THE FERTILITY DECLINE IN THE UNITED STATES: SCHOOLING AND INCOME

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Hansen, Casper Worm; Jensen, Peter Sandholt; Lønstrup, Lars

2017-01-01

This study investigates the determinants of the fertility transition in the United States from 1850 to the end of the 20th century. We find a robust negative relation between years of schooling and fertility. The magnitude of our baseline estimate suggests that the rise in schooling accounts...... for about 60% of the US fertility decline. In contrast, we find no evidence of a robust relation between income per capita and fertility. This pattern corroborates theories stressing the importance of human capital investments in generating a transition from high to low fertility....

Like daughter, like son? Fertility decline and the transformation of gender systems in the family

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Keera Allendorf

2012-10-01

Full Text Available BACKGROUND An important question for population research is whether fertility decline transforms gender systems. OBJECTIVE This paper contributes to answering this broad question by examining how fertility decline may change the relative value and roles of daughters versus sons in families. First, I outline theoretical pathways, suggesting that a key factor is the gender composition of families. As fertility declines, the proportion of families with children of only one gender increases, which may facilitate greater gender symmetry between daughters and sons. Second, I explore how fertility decline may be transforming the relative value and roles of sons and daughters in practice in one place. METHODS The analysis draws primarily on semi-structured interviews with 30 respondents living in one Indian village. RESULTS In recent decades, fertility has declined to at least replacement levels. Respondents also perceive changes in the gender system, including less son preference, more equal schooling for sons and daughters, more freedom in marriage and pre-marital relationships, and perhaps greater daughter support of parents in old age. CONCLUSIONS The results describe changes in the relative value, treatment, and behavior of sons and daughters that are consistent with the theorized effects of fertility decline. Future research is needed, however, to determine whether fertility decline makes a unique causal contribution to changes in the gender system.

Perceptions of oocyte banking from women intending to circumvent age-related fertility decline

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de Groot, Marije; Dancet, Eline; Repping, Sjoerd; Goddijn, Mariette; Stoop, Dominic; van der Veen, Fulco; Gerrits, Trudie

2016-01-01

Women can now opt to bank their oocytes with the intention of increasing their chances of achieving a pregnancy after their fertility has declined. This exploratory study aimed to gain insight into how women, considering oocyte banking to circumvent age-related fertility decline, perceive this

What if fertility decline is not permanent? The need for an evolutionarily informed approach to understanding low fertility.

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Burger, Oskar; DeLong, John P

2016-04-19

'Demographic transition theory' assumes that fertility decline is irreversible. This commonly held assumption is based on observations of recent and historical reductions in fertility that accompany modernization and declining mortality. The irreversibility assumption, however, is highly suspect from an evolutionary point of view, because demographic traits are at least partially influenced by genetics and are responsive to social and ecological conditions. Nonetheless, an inevitable shift from high mortality and fertility to low mortality and fertility is used as a guiding framework for projecting human population sizes into the future. This paper reviews some theoretical and empirical evidence suggesting that the assumption of irreversibility is ill-founded, at least without considerable development in theory that incorporates evolutionary and ecological processes. We offer general propositions for how fertility could increase in the future, including natural selection on high fertility variants, the difficulty of maintaining universal norms and preferences in a large, diverse and economically differentiated population, and the escalating resource demands of modernization. © 2016 The Author(s).

The impact of freedom on fertility decline.

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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.

Educational differentials in cohort fertility during the fertility transition in South Korea

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Sam Hyun Yoo

2014-05-01

Full Text Available Background: While there has been a considerable amount of research on the association between women's education and fertility rates, few of these studies have examined the pattern of fertility differentials over the course of the fertility transition. As a country that has experienced a rapid decline in fertility and marked improvements in women's educational attainment over the last several decades, South Korea represents an ideal case for studying this dynamic association. Objective: The aim of the article is to explain the pattern of fertility differentials by level of education and the contribution of the changes in women's educational attainment to the fertility decline during the fertility transition in South Korea. Methods: Drawing upon data from the Korean censuses conducted between 1970 and 2010, I analyze completed cohort fertility for women born between 1926 and 1970 using demographic-decomposition techniques and cohort parity progression ratios by level of education. Results: The differences in fertility by educational attainment have gradually declined over the transition, with fertility almost converging at a low level among recent birth cohorts. Fertility in South Korea had been declining in all of the social groups until the sub-replacement fertility was reached. The change in women's educational attainment then became an important factor in the further decline in fertility. The trend toward fewer children quickly spread from the most educated to the least educated women throughout the fertility transition. Conclusions: The transformation of fertility behaviors across social strata has been a key element in the Korean fertility transition. Although educational expansion, particularly the introduction of mass education, has contributed to falling fertility in South Korea, the role of education in fertility decline is more pronounced in the diffusion of innovative ideas and behaviors, which reduced fertility differentials across

Poor semen quality may contribute to recent decline in fertility rates.

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Jensen, Tina Kold; Carlsen, Elisabeth; Jørgensen, Niels; Berthelsen, Jørgen G; Keiding, Niels; Christensen, Kaare; Petersen, Jørgen Holm; Knudsen, Lisbeth B; Skakkebaek, Niels E

2002-06-01

During past decades, we have witnessed a remarkable decline in fertility rates (number of births per 1000 women of reproductive age) in the industrialized world. It seems beyond doubt that the enormous social changes of our societies play the major role in this decline, but can it be attributed to changing social structures alone or is a reduced fecundity in the population also a factor? To address this we have focused on trends in teenage pregnancies (which to a large extent are unplanned). During the period in question fertility rates among 15-19 year old Danish women have been falling and the decline in fertility rate is not counterbalanced by an increase in the rate of induced abortion. When seen together with recent results from Denmark, which have shown that more than 30% of 19 year old men from the general population now have sperm counts in the subfertile range, we argue that this fall may not be attributable to social factors, changes in conception practices or diminished sexual activity alone. It seems reasonable also to consider widespread poor semen quality among men as a potential contributing factor to low fertility rates among teenagers. Due to the concern caused by the low sperm count among younger Danish men, the Danish Ministries of Health and Environment have launched a surveillance programme which includes an annual examination of the semen quality in 600 young Danes from the general population. We propose that researchers in other countries with low and falling fertility rates among young women should consider the possibility that semen quality of their younger male cohorts may also have deteriorated.

Ready, Willing, and Able? Impediments to the Onset of Marital Fertility Decline in the United States

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Hacker, J. David

2016-01-01

This study relies on IPUMS samples of the 1850, 1860, 1870, and 1880 censuses, aggregate census data, and the timing of state laws criminalizing abortion to construct regional estimates of marital fertility in the United States and estimate correlates of marital fertility. The results show a significant lag between the onset of marital fertility decline in the nation’s northeastern census divisions and its onset in western and southern census divisions. Empirical models indicate the presence of cultural, economic, and legal impediments to the diffusion of marital fertility control and illustrate the need for more inclusive models of fertility decline. PMID:27757800

The demography of words: The global decline in non-numeric fertility preferences, 1993-2011.

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Frye, Margaret; Bachan, Lauren

2017-07-01

This paper examines the decline in non-numeric responses to questions about fertility preferences among women in the developing world. These types of response-such as 'don't know' or 'it's up to God'-have often been interpreted through the lens of fertility transition theory as an indication that reproduction has not yet entered women's 'calculus of conscious choice'. However, this has yet to be investigated cross-nationally and over time. Using 19 years of data from 32 countries, we find that non-numeric fertility preferences decline most substantially in the early stages of a country's fertility transition. Using country-specific and multilevel models, we explore the individual- and contextual-level characteristics associated with women's likelihood of providing a non-numeric response to questions about their fertility preferences. Non-numeric fertility preferences are influenced by a host of social factors, with educational attainment and knowledge of contraception being the most robust and consistent predictors.

Has Culture Fulled the Great Fertility Decline in Developing Countries since 1960?

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Wang, Cong; Madsen, Jakob; Moslehi, Solmaz

This paper suggests that secularization is one of the driving forces behind the great fertility decline that developing countries are currently undergoing. While large families are valued in gender-stratified and collectivist societies, individualistic and secular societies emphasize gender...... equality and low fertility. Standard fertility models extended with culture are estimated using data for 92 developing countries over the period 1960-2010. External instruments are used to deal with endogeneity. It is found that secularization and reduced infant mortality can explain the bulk...

Economic crisis promotes fertility decline in poor areas: Evidence from Colombia

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Eleonora Davalos

2017-09-01

Full Text Available Background: The effects of an economic recession extend beyond financial spheres and spill over into present and future family decisions via income restrictions and expectations. Hardly any research on the effects of economic recession on fertility outcomes has taken place in developing countries. Objective: This study seeks to explain the effects of economic cycles on fertility outcomes in poor areas. Methods: This paper analyzes fertility trends from the third largest economy in Latin America - Colombia - from 1998 to 2013. We estimate a panel data regression model with state and year fixed effects. Results: On average, periods of recession are associated with fertility decline in poor areas and fertility growth in well-off areas. During an economic crisis, fertility in poor states decreases by 0.002 children per woman, while in well-off states fertility increases by 0.007 children per woman. Conclusions: The impact of an economic crisis on fertility varies depending on poverty. Poor states have procyclical responses while well-off states tend to have countercyclical reactions to economic downturns. Contribution: This study illuminates the procyclical and countercyclical debate, showing that within a country there can be two different responses to an economic downturn.

Impact of migration on fertility in sub-Saharan Africa.

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Brockerhoff, M; Yang, X

1994-01-01

Much lower levels of fertility in urban than rural areas throughout sub-Saharan Africa imply that fertility decline in the region may be facilitated by rapid urbanization and rural-to-urban migration. The present study uses data from Demographic and Health Surveys in six countries--Ghana, Kenya, Mali, Senegal, Togo and Uganda--to assess the impact of long-term rural-urban female migration on fertility. Results of logit analyses indicate that in most countries women who leave the countryside represent the higher fertility segment of the rural population in the years before migration. Migrants' risk of conception declines dramatically in all countries around the time of migration and remains lower in the long run among most migrant groups than among rural and urban nonmigrants. Descriptive analyses suggest that the decline in migrant fertility is related to the rapid and pronounced improvement in standard of living experienced by migrants after settling in the urban area and may be due in part to temporary spousal separation.

Soil fertility decline and economic policy reform in Sub-Saharan Africa

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Heerink, N.B.M.

2005-01-01

Two decades of economic reforms in Africa have not resulted in the anticipated growth in per capita agricultural production. Declining output-fertiliser price ratios, particularly for food crops, contributed to soil fertility depletion and agricultural stagnation. Current prices of agricultural

Assessing soil fertility decline in the tropics using soil chemical data

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Hartemink, A.E.

2006-01-01

Soil fertility decline is perceived to be widespread in the upland soils of the tropics, particularly in sub-Saharan Africa. Most studies have used nutrient balances to assess the degree and extent of nutrient depletion; these have created awareness but suffer methodological problems as several of

Anti-Mullerian hormone levels decline under hormonal suppression: a prospective analysis in fertile women after delivery

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Ortner Iris

2011-07-01

Full Text Available Abstract Background AMH's reported stability during periods of hormonal change makes it a practical tool in assessing ovarian reserve. However, AMH declines with age and age-specific cut-offs remain to be established in women with proven fertility. This study aims to determine age-specific ranges of AMH in women with proven fertility. Methods Two hundred-ten fertile women, aged 18-40 years, were prospectively recruited for AMH measurements within 14 days after delivery and age stratified into 3 groups (18-30, 31-36 and 37-40 years. Eligibility required spontaneous conception within a maximal period of six months. Autoimmune diseases, chemotherapy, radiation, ovarian surgery and polycystic ovary syndrome precluded inclusion. Results 95% confidence intervals of AMH declined with advancing female age from 0.9-1.1 to 0.6-0.9 and 0.2-0.4 ng/mL (P Conclusions Like infertile populations, fertile women demonstrate declining AMH with advancing age. Uniformly lower levels than in infertile women suggest that AMH levels do not appear as stable under all hormonal influences as previously reported.

Family planning and fertility decline in rural Iran: the impact of rural health clinics.

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Salehi-Isfahani, Djavad; Abbasi-Shavazi, M Jalal; Hosseini-Chavoshi, Meimanat

2010-09-01

During the first few years of the Islamic Revolution of 1979, and aided by pro-natal government policies, Iranian fertility was on the rise. In a reversal of its population policy, in 1989, the government launched an ambitious and innovative family planning program aimed at rural families. By 2005, the program had covered more than 90% of the rural population and the average number of births per rural woman had declined to replacement level from about 8 births in the mid 1980s. In this paper, we evaluate the impact of a particular feature of the program - health houses - on rural fertility, taking advantage of the variation in the timing of their construction across the country. We use three different methods to obtain a range of estimates for the impact of health houses on village-level fertility: difference-in-differences (DID), matching DID, and length of exposure. We find estimates of impact ranging from 4 to 20% of the decline in fertility during 1986-1996. (c) 2010 John Wiley & Sons, Ltd.

The Power of the Government: China's Family Planning Leading. Group and the Fertility Decline since 1970

OpenAIRE

Chen, Yi; Huang, Yingfei

2018-01-01

China introduced its world-famous One-Child Policy in 1979. However, its fertility appears to have declined even faster in the early 1970s than it did after 1979. In this study, we highlight the importance of the Family Planning Leading Group in understanding the fertility decline since the early 1970s. In 1970, provinces gradually established an institution named the Family Planning Leading Group to facilitate the restoration of family planning, which had previously been interrupted by the o...

Family planning and fertility decline: a global overview.

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Tabah, L

1977-01-01

Family planning and development policy concerns are not incompatible. The emphasis on development policies at the 1974 World Population Conference at Bucharest did not mean that world governments had lost interest in the population and family planning issue. Although worldwide attitudes toward family planning have become more and more favorable, this has not yet meant great impact on world demographic trends. The "inertia factor," i.e., the effects of high birthrates in the previous generation, will camouflage declining birthrates for some time to come. The trend of fertility reduction which was perceptible only among small populations a few years ago is also becoming manifest in larger Third World countries. Mortality rate declines have slowed down but there is no rising mortality due to starvation in any country. At present, food demand exceeds availability for 80% of the Third World population. It is predicted that the food deficit will increase 70% by the year 2000.

Fertility Decline, Gender Composition of Families, and Expectations of Old Age Support.

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Allendorf, Keera

2015-08-01

Recent fertility declines in non-Western countries may have the potential to transform gender systems. One pathway for such transformations is the creation of substantial proportions of families with children of only one gender. Such families, particularly those with only daughters, may facilitate greater symmetry between sons and daughters. This article explores whether such shifts may influence gendered expectations of old age support. In keeping with patriarchal family systems, old age support is customarily provided by sons, but not daughters, in India. Using data from the 2005 Indian Human Development Survey, I find that women with sons overwhelmingly expect old age support from a son. By contrast, women with only daughters largely expect support from a daughter or a source besides a child. These findings suggest that fertility decline may place demographic pressure on gendered patterns of old age support and the gender system more broadly.

Socioeconomic status and fertility decline

DEFF Research Database (Denmark)

Dribe, Martin; Breschi, Marco; Gagnon, Alain

2017-01-01

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...

[Fertility change in Mexico and the politics of population].

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Zavala De Cosio, M E

1993-01-01

This introduction to a detailed study of fertility change in Mexico assesses the available fertility data and describes the sources used, traces the beginning and course of the demographic transition in Mexico, and describes the work. Mexico's demographic transition began around 1930 with the acceleration of mortality decline. The considerable time lag between the mortality decline and the beginning of the fertility decline resulted in a period of very rapid growth. Between 1955 and 1975, the growth rate exceeded 3% annually. The start of the fertility decline dated to about 1970, the time of a major reform of population policy and creation of institutions to reduce growth. But the fertility decline was not solely the result of population programs. An incipient fertility decline could be observed in the metropolitan and more educated population sectors beginning in the early 1960s. The onset of the mortality decline in the 1930s resulted from the sustained social and economic progress made possible after the conclusion of the Mexican Revolution. Between 1930 and 1980, the adult illiteracy rate declined from 61.2% to 17%, while life expectancy increased from 33 years to 63.2 years. In Mexico as in other Latin American countries, the mortality decline, which disturbed the traditional balance between high mortality and high fertility, was the force setting off the demographic transition and the necessary precursor to fertility decline. The first of two main sections of the book focuses on examination of fertility variations in Mexico since around 1900 using cross-sectional and longitudinal methods of analysis. The second part describes the origins, history, and institutions involved in Mexico's population policies and the demographic programs and their principal results. The influence of population policies in demographic change is assessed, especially in the case of fertility changes induced by family planning programs. Both the first and second parts sought to place

Fertility desires and fertility outcomes.

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Bracher, M; Santow, G

1991-05-01

An Australian 1-in-1000 national probability sample conducted in 1986 yielded 2547 women aged 20-59 who provided detailed life histories on marital unions, childbearing, and contraception. Age specific fertility rates, desired family size, differentials in desired family size, desired fertility and achieved fertility, and sequential family building are examined. The results indicate that the desired family size at 1st marriage has declined only slightly over the past 30 years. 3 children are generally desired, and ver few desire 2. The constance of fertility desires in contrasted with the fertilitydecline to below replacement levels. Several reasons are suggested for the desired family size: the desire is for a family size within the family tradition and modified by the desire to have 1 of each sex, the desire reflects less on intentions but more on normative pressure to become a parent. Marrying is self selecting on the desire for a traditional family of at least 2 children. There is a rising age at marriage as well as a decline in marriages. Desired family size exceeds completed fertility. Period factors and personal circumstances affect fertility intentions. Future inquires should explore the multiple factors relating to fertility, rather than in comparing fertility desires and actual fertility. The data collected on age specific fertility were comparable to official estimates. The fertility decline was evidenced in all groups except teenagers. The decline was nearly 50% for those 20-24 years between the 1050's-80's, 33% for ages 25-29. Marriage patterns explain this decline in part. Between 1971-76, women aged 20-25 were married 37 months out of 60 months in 1971-76 versus 25 out of 60 months in 1981-86. Within the 25 year age group, marital fertility has declined and unmarried fertility, which is low, has risen, Women in a marital union of any kind has remained stable. Fertility within de facto unions, which is lower than within marriage, is higher than

Perceptions of oocyte banking from women intending to circumvent age-related fertility decline.

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de Groot, Marije; Dancet, Eline; Repping, Sjoerd; Goddijn, Mariette; Stoop, Dominic; van der Veen, Fulco; Gerrits, Trudie

2016-12-01

Women can now opt to bank their oocytes with the intention of increasing their chances of achieving a pregnancy after their fertility has declined. This exploratory study aimed to gain insight into how women, considering oocyte banking to circumvent age-related fertility decline, perceive this intervention. We conducted a qualitative study in a Dutch university medical center and held in-depth interviews with women on the waiting list for oocyte banking. We recorded the interviews, transcribed them verbatim and used thematic analysis. All women were financially independent and lived in single-person urban households. They opted for oocyte banking because they wished to share parenthood with a future partner rather than becoming a single parent. This strong desire was key in their interpretation of all aspects of the intervention. Women set aside information about the limited success rates and potential risks, as they were optimistic about their own prognosis, thought that the chances for success were equally likely as the chances it would fail, and because of "anticipatory regret". They perceived oocyte banking as a "helping hand" to achieve shared parenthood. Although women found the costs of the intervention high, they were willing to invest their money to increase their chances for shared parenthood. Oocyte banking allows women to circumvent age-related fertility decline. The prospect of potential shared parenthood overrules the perceived health risks and burden. Health professionals should take this into account when informing potential users of oocyte banking. © 2016 Nordic Federation of Societies of Obstetrics and Gynecology.

Europe-wide fertility trends since the 1990s: Turning the corner from declining first birth rates

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Marion Burkimsher

2015-03-01

Full Text Available Background: In the period 1995-2002 there was a change in trajectory from decline to rise in first birth fertility rates across Europe. Objective: A number of previous studies have looked at the demographic causes of the transition. This study evaluates their conclusions by analysing a comprehensive set of indicators for fifteen countries with data in the Human Fertility Database. Methods: Comparisons are made between the four years before and after the fertility trough, to discover what changed between these two periods. Results: In the period before the trough, peak age-specific fertility rates were falling; these tended to stabilise after the year of minimum fertility. The width of the fertility curve, however, was already widening in the 1990s, and this trend continued. The transition from fall to rise in TFR1 occurred when the increase in the width of the curve more than compensated for any further falls in peak rates; this explanation is valid for countries in both Eastern and Western Europe. The increasing width of the fertility curve was caused by two factors: the decline in young (pre-modal fertility slowed, whilst the rise in older (post-modal fertility accelerated. For some countries, a rise in underlying cohort rates also contributed to the rise in period rates. The likelihood of childless women entering motherhood also rose in some but not all countries. Conclusions: During the 1990s, women were postponing first births across Europe. A rebound took place for several reasons, with the overarching driver being the strong rise in late fertility. Comments: In some countries the steep rise in late fertility had an unexpected and paradoxical effect on postponement rates (defined as the year-on-year increase in mean age at first birth. Recuperation at post-modal ages of postponed first births caused an acceleration in 'postponement' rates, as defined by this metric.

The link between rapid enigmatic amphibian decline and the globally emerging chytrid fungus.

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Lötters, Stefan; Kielgast, Jos; Bielby, Jon; Schmidtlein, Sebastian; Bosch, Jaime; Veith, Michael; Walker, Susan F; Fisher, Matthew C; Rödder, Dennis

2009-09-01

Amphibians are globally declining and approximately one-third of all species are threatened with extinction. Some of the most severe declines have occurred suddenly and for unknown reasons in apparently pristine habitats. It has been hypothesized that these "rapid enigmatic declines" are the result of a panzootic of the disease chytridiomycosis caused by globally emerging amphibian chytrid fungus. In a Species Distribution Model, we identified the potential distribution of this pathogen. Areas and species from which rapid enigmatic decline are known significantly overlap with those of highest environmental suitability to the chytrid fungus. We confirm the plausibility of a link between rapid enigmatic decline in worldwide amphibian species and epizootic chytridiomycosis.

Explaining the role of proximate determinants on fertility decline among poor and non-poor in Asian countries.

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Nabanita Majumder

Full Text Available We examined the overall contributions of the poor and non-poor in fertility decline across the Asian countries. Further, we analyzed the direct and indirect factors that determine the reproductive behaviour of two distinct population sub-groups.Data from several new rounds of DHS surveys are available over the past few years. The DHS provides cross-nationally comparable and useful data on fertility, family planning, maternal and child health along with the other information. Six selected Asian countries namely: Bangladesh, India, Indonesia, Nepal, Philippines, and Vietnam are considered for the purpose of the study. Three rounds of DHS surveys for each country (except Vietnam are considered in the present study.Economic status is measured by computing a "wealth index", i.e. a composite indicator constructed by aggregating data on asset ownership and housing characteristics using principal components analysis (PCA. Computed household wealth index has been broken into three equal parts (33.3 percent each and the lowest and the highest 33.3 percent is considered as poor and non-poor respectively. The Bongaarts model was employed to quantify the contribution of each of the proximate determinants of fertility among poor and non-poor women.Fertility reduction across all population subgroups is now an established fact despite the diversity in the level of socio-economic development in Asian countries. It is clear from the analysis that fertility has declined irrespective of economic status at varying degrees within and across the countries which can be attributed to the increasing level of contraceptive use especially among poor women. Over the period of time changing marriage pattern and induced abortion are playing an important role in reducing fertility among poor women.Fertility decline among majority of the poor women across the Asian countries is accompanied by high prevalence of contraceptive use followed by changing marriage pattern and induced

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

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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 population.  Fertility 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

Role of Conflict in shaping fertility preferences in Rwanda

NARCIS (Netherlands)

Rutayisire, P.-C.; Broekhuis, A.; Hooimeijer, P.

2013-01-01

Conflicts affect the social and economic conditions that could account for the stall in fertility decline in Sub-Saharan Africa. For Rwanda, the total fertility rate decreased very rapidly to 6.1 in the eighties but stalled at that level in the nineties. Part of the stall can be attributed to a lack

Risks of rapid decline renal function in patients with type 2 diabetes

Institute of Scientific and Technical Information of China (English)

Yi-Jing; Sheen; Wayne; HH; Sheu

2014-01-01

Progressive rising population of diabetes and related nephropathy, namely, diabetic kidney disease and associated end stage renal disease has become a major global public health issue. Results of observational studies indicate that most diabetic kidney disease progresses over decades; however, certain diabetes patients display a rapid decline in renal function, which may lead to renal failure within months. Although the definition of rapid renal function decline remained speculative, in general,it is defined by the decrease of estimated glomerular filtration rate(e GFR) in absolute rate of loss or percent change. Based on the Kidney Disease: Improving Global Outcomes 2012 clinical practice guidelines, a rapid decline in renal function is defined as a sustained declinein e GFR of > 5 m L/min per 1.73 m2 per year. It has been reported that potential factors contributing to a rapid decline in renal function include ethnic/genetic and demographic causes, smoking habits, increased glycated hemoglobin levels, obesity, albuminuria, anemia, low serum magnesium levels, high serum phosphate levels, vitamin D deficiency, elevated systolic blood pressure, pulse pressure, brachial-ankle pulse wave velocity values, retinopathy, and cardiac autonomic neuropathy. This article reviews current literatures in this area and provides insight on the early detection of diabetic subjects who are at risk of a rapid decline in renal function in order to develop a more aggressive approach to renal and cardiovascular protection.

The fertility transition in Cuba and the Federal Republic of Korea: the impact of organised family planning.

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Noble, J; Potts, M

1996-04-01

South Korea and Cuba are dissimilar in religion, economy, culture and attitudes toward premarital sexual relations. In 1960, Korea instituted a national family planning programme to combat rapid population growth. Cuba explicitly rejected Malthusian policies, but made family planning universally available in 1974 in response to health needs. Both countries have undergone rapid fertility declines and today have less than replacement level fertility. Both countries have also used a similar mixture of methods, including a high prevalence of female sterilisation. Abortion has played a major role in the fertility decline of both countries, rising in the first half of the fertility transition and then falling, although remaining a significant variable in the second half. It is concluded that access to contraception, voluntary sterilisation, and safe abortion has a direct impact on fertility and has been associated with a rapid fall in family size in two very different countries.

Global fertility and population trends.

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Bongaarts, John

2015-01-01

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

Fertility Decline, Gender Composition of Families, and Expectations of Old Age Support

OpenAIRE

Allendorf, Keera

2014-01-01

Recent fertility declines in non-Western countries may have the potential to transform gender systems. One pathway for such transformations is the creation of substantial proportions of families with children of only one gender. Such families, particularly those with only daughters, may facilitate greater symmetry between sons and daughters. This article explores whether such shifts may influence gendered expectations of old age support. In keeping with patriarchal family systems, old age sup...

[Fertility transition in Peru].

Science.gov (United States)

Ferrando, D; Aramburu, C E

1992-12-01

Data from national censuses and sample surveys are the basis for this examintion of differential fertility and the fertility transition in Peru. Changes in the level and structure of fertility in the 3 major geographic regions are compared, and the role of contraceptive usage and nuptiality changes in the fertility decline are analyzed. Peru's total fertility rate was estimated at 6.85 in 1965 and has since declined to 6.56 in 1965-70, 6.00 in 1970-75, 5.30 in 1975-80, 4.65 in 1980-85, and 4.00 in 1985-90. The fertility decline varied in intensity and timing in the geographic regions. A clear fertility decline began among upper and middle income groups in the principal cities in the 1960s, spreading gradually to the urban low income sectors. Not until the late 1970s did the fertility decline spread to the rest of the population, coinciding with the years of severe economic crisis. The urban total fertility rate declined from 6 to 3.77 during 1961-86, but rural fertility increased through 1972 to 8.12, before declining slightly to 7.62 in 1981 and more markedly to 6.65 in 1986. Sociocultural and economic differences between Peru's natural regions are appreciable, and account for the contrasts in fertility trends. The greatest changes occurred in metropolitan Lima, which already had relatively low fertility in 1961. Its total fertility rate declined 44% from 5.6 in 1961 to 3.13 in 1986. Fertility declined by slightly under 40% in the rest of the coast, by almost 25% in the jungle, and by scarcely 14% in the sierra. The total fertility rates in 1961 and 1986, respectively, were 6.38 and 4.13 on the coast, 6.64 and 6.45 in the highlands, and 7.92 and 5.97 in the lowlands. The fertility decline, especially in the lower classes, was a response initially to the process of cultural modernization which in slightly over 2 decades saw a profound transformation of Peru from a rural, Andean, illiterate, and agrarian society to an urban, coastal, literate, and commercial society

[Fertility transition in Brazil. Causes and consequences].

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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

Rapid and accurate evaluation of the quality of commercial organic fertilizers using near infrared spectroscopy.

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Chang Wang

Full Text Available The composting industry has been growing rapidly in China because of a boom in the animal industry. Therefore, a rapid and accurate assessment of the quality of commercial organic fertilizers is of the utmost importance. In this study, a novel technique that combines near infrared (NIR spectroscopy with partial least squares (PLS analysis is developed for rapidly and accurately assessing commercial organic fertilizers quality. A total of 104 commercial organic fertilizers were collected from full-scale compost factories in Jiangsu Province, east China. In general, the NIR-PLS technique showed accurate predictions of the total organic matter, water soluble organic nitrogen, pH, and germination index; less accurate results of the moisture, total nitrogen, and electrical conductivity; and the least accurate results for water soluble organic carbon. Our results suggested the combined NIR-PLS technique could be applied as a valuable tool to rapidly and accurately assess the quality of commercial organic fertilizers.

Rapid and accurate evaluation of the quality of commercial organic fertilizers using near infrared spectroscopy.

Science.gov (United States)

Wang, Chang; Huang, Chichao; Qian, Jian; Xiao, Jian; Li, Huan; Wen, Yongli; He, Xinhua; Ran, Wei; Shen, Qirong; Yu, Guanghui

2014-01-01

The composting industry has been growing rapidly in China because of a boom in the animal industry. Therefore, a rapid and accurate assessment of the quality of commercial organic fertilizers is of the utmost importance. In this study, a novel technique that combines near infrared (NIR) spectroscopy with partial least squares (PLS) analysis is developed for rapidly and accurately assessing commercial organic fertilizers quality. A total of 104 commercial organic fertilizers were collected from full-scale compost factories in Jiangsu Province, east China. In general, the NIR-PLS technique showed accurate predictions of the total organic matter, water soluble organic nitrogen, pH, and germination index; less accurate results of the moisture, total nitrogen, and electrical conductivity; and the least accurate results for water soluble organic carbon. Our results suggested the combined NIR-PLS technique could be applied as a valuable tool to rapidly and accurately assess the quality of commercial organic fertilizers.

Rapid cognitive decline: not always Creutzfeldt-Jakob disease.

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Randall, A; Ellis, R; Hywel, B; Davies, R R; Alusi, S H; Larner, A J

2015-01-01

A patient with rapidly progressive cognitive decline over an approximately four month period was suspected to have sporadic Creutzfeldt-Jakob disease. Features thought to support this diagnosis included psychiatric symptoms (anxiety and depression), visual hallucinations and a visual field defect. However, the finding of papilloedema broadened the differential diagnosis. Although standard brain imaging and electroencephalography had shown only non-specific abnormalities, subsequent cerebral angiography disclosed an intracranial dural arteriovenous fistula. Following embolisation, the patient made a good functional recovery. Intracranial dural arteriovenous fistula merits consideration in any patient with subacute cognitive decline, and should be included in the differential diagnosis of sporadic Creutzfeldt-Jakob disease.

Soil fertility decline: definitions and assessment

NARCIS (Netherlands)

Hartemink, A.E.

2006-01-01

In permanent agricultural systems, soil fertility is maintained through applications of manure, other organic materials, inorganic fertilizers, lime, the inclusion of legumes in the cropping systems, or a combination of these. In many parts of the world the availability, use, and profitability of

The German social democratic party (SPD) and the debate on the fertility decline in the German Empire (1870~1918).

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Mun, Soo-Hyun

2011-12-31

This paper aimed to examine the debate over the fertility decline in the German Empire, focusing on the role of the SPD. During the German Empire, the fertility rate dramatically declined and the growing awareness of a continuous decline in the birth rate prompted a massive debate among politicians, doctors, sociologists, and feminist activists. The fertility decline was negatively evaluated and generated consciousness of crisis. However, it was not the only way to face this new phenomenon. Indeed, the use of birth control among the upper class was interpreted as a part of a modernizing process. As the same phenomenon reached the working class, it suddenly became a social problem and was attributed to the SPD. The debate over the fertility decline in imperial German society ridden with a fierce class conflict was developed into a weapon against the SPD. Contrary to the assumption of conservative politicians, the SPD had no clear-cut position on this issue. Except for a few politicians like Kautsky and the doctors who came into frequent contact with the workers, the "birth strike" was not listed as the main interest of the SPD. Even Clara Zetkin, the leader of the Social Democratic women's organization viewed it as a concern of the individual person which could not be incorporated in the party program. The women's organization of the SPD put priority on class conflict rather than issues specific to women. As a result, the debate over the birth rate decline within the SPD was not led by the women themselves. There could have been various means to stimulate the birth rate. Improvement in the welfare system, such as tax relief for large families, better housing conditions, and substantial maternity protection, could have been feasible solutions to the demographic crisis. However, Germany chose to respond to this crisis by imposing legal sanctions against birth control. In addition to paragraphs 218-220 of the German criminal law enacted in 1872 which prescribed penal

Fertility decline: transition or transformation?

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Freedman, J

1981-01-01

This essay argues on the basis of evidence from Northern Rwanda that economic theories of fertility which fail to take into account the value of children for reproducing a community's social relations are of limited value in traditional noncapitalist or peasant societies. Regarding the transition to low fertility as an adjustment of the population to available resources ignores the fact that many families in the developing world regard their children as absolute values, not values relative to other resources, and therefore the transition to lower fertility is a dramatic change rather than an adjustment. The Kiga of Rwanda have in the last 20 years or so become differentiated into a group of richer households with excess land and a labor shortage and poorer households with excess labor and a land shortage. In the face of severe material shortages, the poorer families continue to desire and have almost as many children as the richer. Among women aged 25-35, the poorer group had on average 5.5 children while the wealthier had 3.9 on average. Kiga families are embedded in larger social units which provide social insurance against misfortune, and having many children thus reconstitutes a social value which minimizes the impact of misfortune. High fertility appears to occur in social economies where there is no reasonable motivation for reducing family size; where high value is placed on the survival of the collectivity and on the reproduction of concrete social relations, the only rational behavior is to have many children.

Certainty of meeting fertility intentions declines in Europe during the 'Great Recession'

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Maria Rita Testa

2014-09-01

Full Text Available Background: Relatively little research has been conducted on how economic recessions impact fertility intentions. In particular, uncertainty in reproductive intentions has not been examined in relation to economic shocks. Objective: The purpose of this paper is to estimate the impact of individuals' perception of negative changes in both their own and their country's economic performance on reproductive intentions in Europe during the time of the 'Great Recession' (2006-2011. Crucially, we examine both intentions and stated certainty of meeting these intentions. Methods: Using the 2011 Eurobarometer survey for 27 European countries, fertility intentions and reproductive uncertainty are regressed on individuals' perceptions of past trends in country's economic situation, household's financial situation, and personal job situation. Multilevel ordinal regressions models are run separately for people at parities zero and one as well as controlling for a set of socio-demographic variables. Results: A worsening in the households' financial situation, as perceived in the years of the economic crisis, does not affect people's fertility intentions but rather the certainty of meeting these intentions. This relationship holds true at the individual-level for childless people. The more negative the individual's assessment of the household's financial situation, the higher the reproductive uncertainty. While this works exclusively at the country-level for people at parity one, the higher the share of people‟s pessimism on households' financial situation in the country the more insecure individuals of such a country are about having additional children. Conclusions: The empirical evidence suggests that individuals' uncertainty about realising their fertility intentions has risen in Europe and is positively linked to people's perceived household financial difficulties. If European economies continue to fare poorly, fertility intentions could eventually start

The rapid decline of the prompt emission in Gamma-Ray Bursts

CERN Document Server

Dado, Shlomo; De Rújula, Alvaro

2008-01-01

Many gamma ray bursts (GRBs) have been observed with the Burst-Alert and X-Ray telescopes of the SWIFT satellite. The successive `pulses' of these GRBs end with a fast decline and a fast spectral softening, until they are overtaken by another pulse, or the last pulse's decline is overtaken by a less rapidly-varying `afterglow'. The fast decline-phase has been attributed, in the standard fireball model of GRBs, to `high-latitude' synchrotron emission from a collision of two conical shells. This interpretation does not agree with the observed spectral softening. The temporal behaviour and the spectral evolution during the fast-decline phase agree with the predictions of the cannonball model of GRBs.

Determinants of fertility in Rwanda in the context of a fertility transition: a secondary analysis of the 2010 Demographic and Health Survey.

Science.gov (United States)

Ndahindwa, Vedaste; Kamanzi, Collins; Semakula, Muhammed; Abalikumwe, François; Hedt-Gauthier, Bethany; Thomson, Dana R

2014-12-13

Major improvements to Rwanda's health system, infrastructure, and social programs over the last decade have led to a rapid fertility transition unique from other African countries. The total fertility rate fell from 6.1 in 2005 to 4.6 in 2010, with a 3-fold increase in contraceptive usage. Despite this rapid national decline, many women still have large numbers of children. This study investigates predictors of fertility during this fertility transition to inform policies that improve individuals' reproductive health and guide national development. We used Poisson regression to separately model number of children born to ever married/cohabitated women (n = 8,309) and never married women (n = 1,220) age 15 to 49 based on 2010 Rwanda Demographic and Health Survey data. We used backward stepwise regression with a time offset to identify individual and household factors associated with woman's fertility level, accounting for sampling weights, clustering, and stratification. In ever married/cohabitating women, high fertility was significantly associated (p Rwanda's national fertility rate and support families to achieve their desired fertility. Strategies include policies and programs that promote delayed sexual debut via educational and economic opportunities for women, improved access to reproductive health information and services at schools and via health campaigns, and involvement of men in family planning decision making.

[Fertility in rural and urban areas of Mexico].

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Garcia Y Garma, I O

1989-01-01

Data from 6 fertility surveys conducted in Mexico between 1969-87 were used to compare rural and urban fertility and to determine whether a significant level of contraceptive usage could be achieved in rural areas despite their lack of socioeconomic development. Age-specific marital fertility rates were calculated for the 4 national-level and 2 rural fertility surveys. The index of fertility control developed by Coale and Trussel was calculated for rural, urban, and all areas. The marital total fertility rate in rural areas declined from 10.6 in 1970 to 7.4 in 1982, a decline of 2.5% annually. From 1982-87 the annual rate of decline in rural fertility slowed to 1.6%, reaching 6.8 children in 1987. The urban marital total fertility rate declined from 7.72 in 1976 to 5.03 in 1987, while the marital total fertility rate for Mexico as a whole declined from 9.04 in 1976 to 5.85 in 1987. The indices of fertility control showed slowly increasing use of contraception in rural areas starting from the very low level of 1969. The urban index of fertility control showed some contraceptive use for all age groups in all surveys. The increases in contraceptive usage were considerable in rural areas from 1976-82 and much less marked in urban areas. From 1982-87 the inverse was observed and the fertility decline in urban areas was more marked. The condition of natural fertility found in rural areas in 1969 subsequently disappeared. Over time, fertility decline and use of contraception have intensified. Contraception is widely practiced in urban areas and is continuing to become more prevalent. The rural fertility decline in 1976-82 suggests that at least sometimes increases in fertility control are more important in rural areas than in urban areas. The theory of modernization, which holds that fertility decline in developed countries is attributable to factors associated with the process of modernization, thus comes into question. However, it is probable that a sustained fertility

On the fertility transition in Africa

DEFF Research Database (Denmark)

Mveyange, Anthony Francis

A consensus among social scientists is that fertility rates in Africa are declining. What determines these declines? I present fresh evidence that shows education, especially for women, is an important determinant of the fertility transition in Africa. This finding is consistent with the predicti......A consensus among social scientists is that fertility rates in Africa are declining. What determines these declines? I present fresh evidence that shows education, especially for women, is an important determinant of the fertility transition in Africa. This finding is consistent...... with the predictions of the unified growth theory and sheds important insights in explaining the sustained income growth Africa has experienced since 1995. The paper also shows that the effects of income per capita and child mortality on fertility rates are non-robust and inconsistent with the predictions...

An empirical investigation of female labor-force participation, fertility, age at marriage, and wages in Korea.

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Lee, B S; Mcelwain, A M

1985-07-01

The Korean experience raises questions about the assumption that successful economic development and equitable income distribution are preconditions for rapid fertility declines. During the 1960-70 decade, the total fertility rate in Korea declined by 36% and the crude birth rate fell by 33%, in the absence of significant economic development. This paper uses data from the 1974 Korean Fertility Survey to explore the relationships between the factors responsible for this rapid fertility decline. A simultaneous equation model of fertility, age at marriage, extent of labor force participation during marriage, quality of children, and wages is developed and tested. Rather than to provide definitive measures of these interrelationships, the aim was to investigate the utility of treating several variables as being jointly determined. The results suggest that parental education affects fertility by influencing age at marriage, implying that adult education programs will have little effect on marital fertility. There was some evidence that working women whose jobs are compatible with child care have more children than nonworking women, a finding that should be considered in planning increased job opportunities for women. Urbanized women and those who work before marriage tend to marry later than their less urbanized counterparts or women who do not work prior to marriage. Finally, women who used modern methods of birth control had significantly lower fertility than nonusers of modern methods. There is concern that the Government has reduced budgetary appropriations to family planning since the goal of reducing the annual population growth rate from 3% in 1960 to 2% in 1970 was achieved. It is suggested that family planning expenditures should be deployed to areas such as urban slums that have not yet been reached by family planning programs.

Is fertility falling in Zimbabwe?

Science.gov (United States)

Udjo, E O

1996-01-01

With an unequalled contraceptive prevalence rate in sub-Saharan Africa, of 43% among currently married women in Zimbabwe, the Central Statistical Office (1989) observed that fertility has declined sharply in recent years. Using data from several surveys on Zimbabwe, especially the birth histories of the Zimbabwe Demographic and Health Survey, this study examines fertility trends in Zimbabwe. The results show that the fertility decline in Zimbabwe is modest and that the decline is concentrated among high order births. Multivariate analysis did not show a statistically significant effect of contraception on fertility, partly because a high proportion of Zimbabwean women in the reproductive age group never use contraception due to prevailing pronatalist attitudes in the country.

The Trade-Off between Female Fertility and Longevity during the Epidemiological Transition in the Netherlands

DEFF Research Database (Denmark)

Kaptijn, Ralf; Thomese, Fleur; Liefbroer, Aart C

2015-01-01

as an evolutionary trade-off between reproduction and survival. We examine the relationship between fertility and longevity during the epidemiological transition in the Netherlands. This period of rapid decline in mortality from infectious diseases offers a good opportunity to study the relationship between...... fertility and longevity, using registry data from 6,359 women born in The Netherlands between 1850 and 1910. We hypothesize that an initially negative relationship between women's fertility and their longevity gradually turns less negative during the epidemiological transition, because of decreasing costs...

Do cycle disturbances explain the age-related decline of female fertility? Cycle characteristics of women aged over 40 years compared with a reference population of young women.

NARCIS (Netherlands)

Zonneveld, P. van; Scheffer, G.J.; Broekmans, F.J.; Blankenstein, M.A.; Jong, F.H. de; Looman, C.W.; Habbema, J.D.F.; Velde, E.R. te

2003-01-01

BACKGROUND: The cause of declining fertility with age, in women who still have regular menstrual cycles, is not clear. METHODS: Follicle development, endometrial growth and hormonal patterns were evaluated in cycles of older women (aged 41-46 years; n = 26) who previously were normally fertile, and

Economic recession and fertility in the developed world.

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Sobotka, Tomáš; Skirbekk, Vegard; Philipov, Dimiter

2011-01-01

This article reviews research on the effects of economic recessions on fertility in the developed world. We study how economic downturns, as measured by various indicators, especially by declining GDP levels, falling consumer confidence, and rising unemployment, were found to affect fertility. We also discuss particular mechanisms through which the recession may have influenced fertility behavior, including the effects of economic uncertainty, falling income, changes in the housing market, and rising enrollment in higher education, and also factors that influence fertility indirectly such as declining marriage rates. Most studies find that fertility tends to be pro-cyclical and often rises and declines with the ups and downs of the business cycle. Usually, these aggregate effects are relatively small (typically, a few percentage points) and of short durations; in addition they often influence especially the timing of childbearing and in most cases do not leave an imprint on cohort fertility levels. Therefore, major long-term fertility shifts often continue seemingly uninterrupted during the recession—including the fertility declines before and during the Great Depression of the 1930s and before and during the oil shock crises of the 1970s. Changes in the opportunity costs of childbearing and fertility behavior during economic downturn vary by sex, age, social status, and number of children; childless young adults are usually most affected. Furthermore, various policies and institutions may modify or even reverse the relationship between recessions and fertility. The first evidence pertaining to the recent recession falls in line with these findings. In most countries, the recession has brought a decline in the number of births and fertility rates, often marking a sharp halt to the previous decade of rising fertility rates.

The fertility myth: Israeli students' knowledge regarding age-related fertility decline and late pregnancies in an era of assisted reproduction technology.

Science.gov (United States)

Hashiloni-Dolev, Yael; Kaplan, Amit; Shkedi-Rafid, Shiri

2011-11-01

As in many advanced societies, the age at first birth and the rate of post-menopausal pregnancies in Israel are constantly increasing. Since Israeli university students are the most likely population to postpone parenthood, this study aims at evaluating their awareness of: (i) women's age-related fertility decline; (ii) age-dependent success rates of IVF technology and (iii) medical procedures allowing late and post-menopausal pregnancies. Israeli undergraduate students (n= 410), attending four academic institutions and studying in different fields, completed a structured questionnaire in the 2009/2010 academic year. Students overestimated women's chances of spontaneous pregnancy in all age groups, whereas women's chances of achieving a live birth following IVF treatment were overestimated only for ages 40 years and above. Regarding both spontaneous and IVF pregnancies, success rates of very late pregnancies (beyond 45 years and after menopause) were greatly overestimated. Only 11% of the students knew that genetic motherhood is unlikely to be achieved from the mid-40s onward, unless using oocytes frozen in advance. The findings demonstrate entrenched fertility myths among Israeli students, particularly the false belief in the possibility of late (beyond 35 years) and very late genetic motherhood. This can be explained by technological 'hype' and favorable media coverage of very late pregnancies. Since this may culminate in involuntary childlessness, it is highly important to increase the awareness of the Israeli public on the subject of fertility. However, as our sample is not representative of the Israeli student population, our findings should be tested in future studies.

Fertility reduction programmes should accompany land reforms.

Science.gov (United States)

Atiku, J

1994-01-01

Changes in population size both affect and are affected by the rate of development. With the total world population estimated to be 5.7 billion in mid-1994 and annual growth at 1.7%, declines in total fertility rates and overall growth rates in developing countries have not been sufficient to precipitate a decline in actual numbers. The population of developing countries has doubled from 1962 to 1994. The highest growth rates are expected to be in sub-Saharan Africa, but the largest absolute increase in population is expected to occur in Asia. Uganda's population has increased from 4.9 to 16.7 million from 1948 to 1991. At the current rate of increase (2.5%) and taking AIDS into account, Uganda's population is expected to double in 28 years. Rapid population growth in developing countries can be explained by the following factors: 1) high levels of morbidity and mortality which threaten child survival and encourage large families; 2) early marriage which extends reproductive activity; 3) a high value placed on children, especially sons; 4) unmet needs for family planning; 5) widespread poverty which causes children to be viewed as old age security; and 6) population momentum which would contribute to growth even if replacement fertility were achieved because of the current age-sex structure of the population. The impact of rapid population growth on development requires further study, but some things are clear. Economic development is hindered when the number of dependent and poor individuals in a population increases. High rates of fertility result in poor infant and maternal health. The provision of social welfare services and the capacity for providing basic services such as health care, education, safe water, and sanitation is strained by rapid population growth. Also, the quality of the environment is adversely affected by rapid population growth. Population policies should be developed for each country and should emphasize activities to improve individual

Rapid analysis of fertilizers by the direct-reading thermometric method.

Science.gov (United States)

Sajó, I; Sipos, B

1972-05-01

The authors have developed rapid methods for the determination of the main components of fertilizers, namely phosphate, potassium and nitrogen fixed in various forms. In the absence of magnesium ions phosphate is precipitated with magnesia mixture; in the presence of magnesium ions ammonium phosphomolybdate is precipitated and the excess of molybdate is reacted with hydrogen peroxide. Potassium is determined by precipitation with silico-fluoride. For nitrogen fixed as ammonium salts the ammonium ions are condensed in a basic solution with formalin to hexamethylenetetramine; for nitrogen fixed as carbamide the latter is decomposed with sodium nitrite; for nitrogen fixed as nitrate the latter is reduced with titanium(III). In each case the temperature change of the test solution is measured. Practically all essential components of fertilizers may be determined by direct-reading thermometry; with this method and special apparatus the time of analysis is reduced to at most about 15 min for any determination.

Fertility trends and prospects in East and South-East Asian countries and implications for policies and programmes.

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Leete, R

1991-01-01

Fertility trends and prospects for east and southeast Asian countries including cities in China, Taiwan, the Republic of Korea, Thailand, Indonesia, Malaysia, the Philippines, Myanmar, and Viet Nam are described. Additional discussion focuses on family planning methods, marriage patterns, fertility prospects, theories of fertility change, and policy implications for the labor supply, labor migrants, increased female participation in the labor force (LFP), human resource development, and social policy measures. Figures provide graphic descriptions of total fertility rates (TFRS) for 12 countries/areas for selected years between 1960-90, TFR for selected Chinese cities between 1955-90, the % of currently married women 15-44 years using contraception by main method for selected years and for 10 countries, actual and projected TFR and annual growth rates between 1990-2020 for Korea and Indonesia. It is noted that the 1st southeast Asian country to experience a revolution in reproductive behavior was Japan with below replacement level fertility by 1960. This was accomplished by massive postponement in age at marriage and rapid reduction in marital fertility. Fertility was controlled primarily through abortion. Thereafter every southeast Asian country experienced fertility declines. Hong Kong, Penang, Shanghai, Singapore, and Taipei and declining fertility before the major thrust of family planning (FP). Chinese fertility declines were reflected in the 1970s to the early 1980s and paralleled the longer, later, fewer campaign and policy which set ambitious targets which were strictly enforced at all levels of administration. Korea and Taiwan's declines were a result of individual decision making to restrict fertility which was encouraged by private and government programs to provide FP information and subsidized services. The context was social and economic change. Indonesia's almost replacement level fertility was achieved dramatically through the 1970s and 1980s by

Age-Related Declines in Early Sensory Memory: Identification of Rapid Auditory and Visual Stimulus Sequences.

Science.gov (United States)

Fogerty, Daniel; Humes, Larry E; Busey, Thomas A

2016-01-01

Age-related temporal-processing declines of rapidly presented sequences may involve contributions of sensory memory. This study investigated recall for rapidly presented auditory (vowel) and visual (letter) sequences presented at six different stimulus onset asynchronies (SOA) that spanned threshold SOAs for sequence identification. Younger, middle-aged, and older adults participated in all tasks. Results were investigated at both equivalent performance levels (i.e., SOA threshold) and at identical physical stimulus values (i.e., SOAs). For four-item sequences, results demonstrated best performance for the first and last items in the auditory sequences, but only the first item for visual sequences. For two-item sequences, adults identified the second vowel or letter significantly better than the first. Overall, when temporal-order performance was equated for each individual by testing at SOA thresholds, recall accuracy for each position across the age groups was highly similar. These results suggest that modality-specific processing declines of older adults primarily determine temporal-order performance for rapid sequences. However, there is some evidence for a second amodal processing decline in older adults related to early sensory memory for final items in a sequence. This selective deficit was observed particularly for longer sequence lengths and was not accounted for by temporal masking.

Ultra-low fertility in South Korea: The role of the tempo effect

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Sam Hyun Yoo

2018-02-01

Full Text Available Background: The total fertility rate (TFR in South Korea has fallen below 1.3 since 2001. The role of the rapid shift toward a late-childbearing pattern in driving Korean fertility decline to this ultra-low level has been little explored until now. Objective: We provide an in-depth analysis of period fertility trends by birth order in South Korea from 1981 to 2015, when the period TFR fell from 2.57 to extremely low levels. Methods: We combine census and birth registration data to estimate period and cohort fertility indicators by birth order. We compare changes in conventional TFR with tempo- and parity-adjusted total fertility rate (TFRp* and their birth-order-specific components. Results: The tempo effect linked to the shift toward delayed childbearing has had a strong and persistent negative influence on period TFRs in South Korea since the early 1980s. Without the shift to later childbearing, period fertility rates in South Korea would consistently stay higher and decline more gradually, reaching a threshold of very low fertility, 1.5, only in 2014. The postponement of childbearing and the resulting tempo effect were strongest in the early 2000s, when Korean TFR reached the lowest levels. More recently, Korean fertility has been characterized by a diminishing tempo effect and falling first and second birth rates. This trend marks a break with the previous pattern of almost universal fertility and a strong two-child family model. Contribution: Our study demonstrates the importance of the tempo effect in explaining the shift to ultra-low fertility in South Korea and in East Asia

The changing timing of births in Iran: an explanation of the rise and fall in fertility after the 1979 Islamic Revolution.

Science.gov (United States)

Erfani, Amir; McQuillan, Kevin

2014-01-01

Studies exploring the course of period fertility in Iran after the 1979 Islamic Revolution have not examined systematically the role played by changes in the timing of births. Using retrospective data from the 2000 Iran Demographic and Health Survey and frailty hazard models, this study finds that the rise in fertility in the early 1980s was due to faster transitions to the first birth among all social groups of women and to the fourth birth largely among illiterate and less educated women. In contrast, the rapid fertility decline after 1985 is attributed to slower transition to successive births, especially to the second, third, and fourth births. These findings point to the importance of education and contraceptive use (measured by length of previous birth interval) as key determinants of birth timing in Iran. Interaction between age at marriage and education positively influenced the timing of births, with stronger effects among highly educated women, suggesting that the onset of rapid fertility decline was likely driven by these highly educated women. Another interaction between the gender of prior children and education shows that birth timing, even among highly educated women, appears to have been influenced by son preference in Iran.

Rudiments of recent fertility decline in Hungary: Postponement, educational differences, and outcomes of changing partnership forms

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Zsolt Spéder

2006-10-01

Full Text Available Our study describes fundamental changes in childbearing behavior in Hungary. It documents current postponement of entry into motherhood (first birth and uncovers signs of delay in second birth. We place the behavioral modifications into historical time and reveal the basic role of the political, economic, and societal transformation of Hungary that started in 1989-1990 in these modifications. We document postponement as well as differentiation, and mothers' highest level of education will represent the structural position of individuals. We shed light on the different speed of postponement and support the assumption of behavioral differences according to the highest level of education. Particular attention will be paid to changing partnership relations: Fertility outcomes remain to be strongly associated with the type of partnership and its development; profound changes in partnership formation, namely the proliferation of cohabitation and the increasing separation rate of first partnerships, may therefore facilitate fertility decline in Hungary. The analysis is based on the first wave of the Hungarian panel survey "Turning points of the life course" carried out in 2001/2002.

Implementation strategy for achieving replacement level fertility.

Science.gov (United States)

1993-01-01

The recommendation of the Bali Declaration on Population and Sustainable Development at the ESCAP regional conference was to adopt strategies for attaining replacement-level fertility of 2.1 or 2.2 children by 2010. East Asian countries, except Mongolia and the Democratic People's Republic of Korea, and the Southeast Asian countries Singapore and Thailand have already reached replacement-level fertility. Most larger Oceanic countries have also done so. Only South Asian Sri Lanka and southern India have attained replacement level. The following conditions slow or hinder the goal, but they do not provide an "absolute" barrier to fertility decline: social welfare schemes and old age security, son preference, lack of government family planning, poverty, relatively high mortality, low status of women, and education status. Theories of demographic transition have postulated that economic and social development initially brings a decline in mortality, and later brings a decline in fertility; and high fertility was an adaptation to high mortality. Policy gets caught in the lag between mortality and fertility decline. Eventually the cultural motives for high fertility are undercut by social and economic development. Although the generalization that economic growth slows fertility is true for South Asia, the correlation is uneven. Forceful government-sponsored family planning programs in Bangladesh and China may lead the way to strategies for decline in ESCAP region. A Thailand study suggested important factors were fundamental social change, the increased cost of children, cultural acceptance of birth control, a latent demand for fertility control, and government efforts in family planning. ESCAP countries have in common relatively high morality and inadequate public health programs, patriarchal structures, and limited female autonomy, poverty and landlessness, lack of community cohesiveness, and inadequate family planning programs. Weaknesses in programs are attributed to

Does low fertility call for new policies in some Asian countries?

Science.gov (United States)

Greenspan, A

1994-06-01

Over the past 2 decades, Japan, China, Singapore, Hong Kong, and South Korea have completed a demographic transition from high birth and death rates and runaway population growth to reduced fertility and mortality and population growth approaching replacement levels. Among the outcomes of fertility decline, 3 have particularly far reaching effects: 1) Changes in family types and structures. Marriage and family formation are postponed, childbearing is compressed into a narrow reproductive span that begins later and ends earlier, and higher-order births become rare. Large families are replaced by small ones, and joint and extended families tend to be replaced by nuclear families. 2) Shifts in the proportions of young and old. Declining fertility means that the population as a whole becomes older. Decreases in the proportion of children provides an opportunity to increase the coverage of education. Increases in the proportion of the elderly means higher medical costs and social and economic problems about care of the aged. 3) Changes in the work force. There is concern that low fertility and shortages of workers will cause investment labor-intensive industries to shift to countries with labor surpluses. Another outcome may be an increase in female participation in the work force. The potential consequences of rapid fertility decline have sparked debate among population experts and policy makers throughout Asia. Current family planning programs will emphasize: 1) offering a choice of methods to fit individual preferences; 2) strengthening programs for sexually active unmarried people; 3) encouraging child spacing and reproductive choice rather than simply limiting the number of births; 4) making information available on the side effects of various family planning methods; 5) providing special information and services to introduce new methods; and 6) promoting the maternal and child health benefits of breast feeding and birth spacing.

Hungary: Secular fertility decline with distinct period fluctuations

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Ferenc Kamarás

2008-07-01

Full Text Available In this study, we demonstrate from different angles that Hungarian fertility basically decreased between 1965 and 2005, but also clearly fluctuated, and showed different patterns in the different periods within this epoch. As a result, the clear communist-era family pattern of "early marriage and childbearing with two children" was replaced, but new family model(s have not yet fully emerged. We could show that profound changes in partnership behaviour -divorce and cohabitation- started before the change of the political regime, but also that changes in partnership relations accelerated after 1990, and that partnerships have become more fragile. In addition, Western-style values of "empty individualism" and consumerism were clearly present under socialism, but their motivating force was tamed by the communist system, in which population policy played a significant role. Of these institutional changes, we ascribe the greatest importance to the expansion in the educational system and the changes in the labour market. We show that, following the changes in the economic system, the conflict between family and work intensified. The synchronic consideration of values, labour market relations, economic development, and population policy; and the relationship of these factors to fertility and nuptiality trends, enabled us to formulate a developmental scheme of four phases concerning the evolution of fertility since 1965.

The impact of development and population policies on fertility in India.

Science.gov (United States)

Jain, A K

1985-01-01

This article examines the impact of development and population policies on fertility decline and regional variations in India during the 1970s. Indicators of development at the household level include female literacy and education, infant mortality, and poverty; at the village level they include availability of such social services as schools, medical facilities, and transportation and communication facilities. Multiple regression analysis of data aggregated at the state level demonstrates that conditions conducive to fertility decline include high adult female literacy and low infant mortality as indicators of social development, and high contraceptive use and, to a lesser extent, high female age at marriage as proximate determinants of fertility. There are reasons to believe that India's national family planning program contributed to the decline in fertility observed since the 1960s. The pace of fertility decline in the future will depend upon the pace of infant mortality decline, enhancement in female education, and improvements in family planning programs.

PTF 12gzk—A rapidly declining, high-velocity type Ic radio supernova

Energy Technology Data Exchange (ETDEWEB)

Horesh, Assaf; Kulkarni, Shrinivas R. [Cahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Corsi, Alessandra [Department of Physics, The George Washington University, 725 21st Street, NW, Washington, DC 20052 (United States); Frail, Dale A. [National Radio Astronomy Observatory, P.O. Box 0, Socorro, NM 87801 (United States); Cenko, S. Bradley [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Ben-Ami, Sagi; Gal-Yam, Avishay; Yaron, Ofer; Arcavi, Iair; Ofek, Eran O. [Department of Particle Physics and Astrophysics, The Weizmann Institute of Science, Rehovot 76100 (Israel); Kasliwal, Mansi M. [Carnegie Institution for Science, Department of Terrestrial Magnetism, 5241 Broad Branch Road, Washington, DC 20008 (United States)

2013-11-20

Only a few cases of Type Ic supernovae (SNe) with high-velocity ejecta (≥0.2 c) have been discovered and studied. Here, we present our analysis of radio and X-ray observations of the Type Ic SN PTF 12gzk. The radio emission declined less than 10 days after explosion, suggesting SN ejecta expanding at high velocity (∼0.3 c). The radio data also indicate that the density of the circumstellar material (CSM) around the supernova is lower by a factor of ∼10 than the CSM around normal Type Ic SNe. PTF 12gzk may therefore be an intermediate event between a 'normal' SN Ic and a gamma-ray-burst-SN-like event. Our observations of this rapidly declining radio SN at a distance of 58 Mpc demonstrates the potential to detect many additional radio SNe, given the new capabilities of the Very Large Array (improved sensitivity and dynamic scheduling), which are currently missed, leading to a biased view of radio SNe Ic. Early optical discovery followed by rapid radio observations would provide a full description of the ejecta velocity distribution and CSM densities around stripped massive star explosions as well as strong clues about the nature of their progenitor stars.

PTF 12gzk—A rapidly declining, high-velocity type Ic radio supernova

International Nuclear Information System (INIS)

Horesh, Assaf; Kulkarni, Shrinivas R.; Corsi, Alessandra; Frail, Dale A.; Cenko, S. Bradley; Ben-Ami, Sagi; Gal-Yam, Avishay; Yaron, Ofer; Arcavi, Iair; Ofek, Eran O.; Kasliwal, Mansi M.

2013-01-01

Only a few cases of Type Ic supernovae (SNe) with high-velocity ejecta (≥0.2 c) have been discovered and studied. Here, we present our analysis of radio and X-ray observations of the Type Ic SN PTF 12gzk. The radio emission declined less than 10 days after explosion, suggesting SN ejecta expanding at high velocity (∼0.3 c). The radio data also indicate that the density of the circumstellar material (CSM) around the supernova is lower by a factor of ∼10 than the CSM around normal Type Ic SNe. PTF 12gzk may therefore be an intermediate event between a 'normal' SN Ic and a gamma-ray-burst-SN-like event. Our observations of this rapidly declining radio SN at a distance of 58 Mpc demonstrates the potential to detect many additional radio SNe, given the new capabilities of the Very Large Array (improved sensitivity and dynamic scheduling), which are currently missed, leading to a biased view of radio SNe Ic. Early optical discovery followed by rapid radio observations would provide a full description of the ejecta velocity distribution and CSM densities around stripped massive star explosions as well as strong clues about the nature of their progenitor stars.

Czech Republic: A rapid transformation of fertility and family behaviour after the collapse of state socialism

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Vladimíra Kantorová

2008-07-01

Full Text Available Following the swift demise of the state-socialist regime in 1989, a profound transformation of family and fertility patterns has taken place in the Czech Republic. Family formation has been postponed and period fertility rates have fallen to very low levels, especially among young adults. Unmarried cohabitation has become relatively widespread and marriages have been progressively delayed or even foregone. These rapid shifts in family-related behaviour were primarily driven by a period change and resulted in a sharp discontinuity in cohort patterns of union formation and childbearing. We argue that the rapid change in family-related behaviour after 1990 was driven by a fundamental shift in the constraints and incentives for childbearing, which was conducive to later and more carefully planned family formation. The rapidity of observed changes can be explained as the outcome of a simultaneous occurrence of several factors, especially the expansion of higher education, the emergence of new opportunities competing with family life, increasing job competition, rising economic uncertainty in young adulthood, and changing partnership behaviour.

Game change in Colorado: widespread use of long-acting reversible contraceptives and rapid decline in births among young, low-income women.

Science.gov (United States)

Ricketts, Sue; Klingler, Greta; Schwalberg, Renee

2014-09-01

Long-acting reversible contraceptive (LARC) methods are recommended for young women, but access is limited by cost and lack of knowledge among providers and consumers. The Colorado Family Planning Initiative (CFPI) sought to address these barriers by training providers, financing LARC method provision at Title X-funded clinics and increasing patient caseload. Beginning in 2009, 28 Title X-funded agencies in Colorado received private funding to support CFPI. Caseloads and clients' LARC use were assessed over the following two years. Fertility rates among low-income women aged 15-24 were compared with expected trends. Abortion rates and births among high-risk women were tracked, and the numbers of infants receiving services through the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) were examined. By 2011, caseloads had increased by 23%, and LARC use among 15-24-year-olds had grown from 5% to 19%. Cumulatively, one in 15 young, low-income women had received a LARC method, up from one in 170 in 2008. Compared with expected fertility rates in 2011, observed rates were 29% lower among low-income 15-19-year-olds and 14% lower among similar 20-24-year-olds. In CFPI counties, the proportion of births that were high-risk declined by 24% between 2009 and 2011; abortion rates fell 34% and 18%, respectively, among women aged 15-19 and 20-24. Statewide, infant enrollment in WIC declined 23% between 2010 and 2013. Programs that increase LARC use among young, low-income women may contribute to declines in fertility rates, abortion rates and births among high-risk women. Copyright © 2014 by the Guttmacher Institute.

Albania: Trends and patterns, proximate determinants and policies of fertility change

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Letizia Mencarini

2008-07-01

Full Text Available For a very long time, Albania has had one of the highest levels of fertility in Europe: in 2002 the total fertility rate of 2.2 children per woman was the highest in Europe. Although this current level is high, the country has experienced a rapid fertility reduction during the last 50 years: a TFR decline from 7 to 2.2. This reduction has occurred in the absence of modern contraception and abortion, which indicates the significance of investments in the social agenda during the communist regime that produced policies with indirect effects on fertility. Most significant of these were policies focused on education, in particular on female education. Social and demographic settings for a further fertility reduction in Albania have been present since 1990. Contraception and abortion have been legalized and available since the early 1990s, but knowledge of their use is still not widespread in the country, largely due to the interplay between traditional and modern norms of Albanian society. This chapter points out that future fertility levels will be determined not only by new policies that might be introduced, but predominantly by the balance of this interplay.

Economic crisis promotes fertility decline in poor areas: Evidence from Colombia

OpenAIRE

Eleonora Davalos; Leonardo Fabio Morales

2017-01-01

Background: The effects of an economic recession extend beyond financial spheres and spill over into present and future family decisions via income restrictions and expectations. Hardly any research on the effects of economic recession on fertility outcomes has taken place in developing countries. Objective: This study seeks to explain the effects of economic cycles on fertility outcomes in poor areas. Methods: This paper analyzes fertility trends from the third largest economy in Latin...

A Multinomial Model of Fertility Choice and Offspring Sex-Ratios in India

OpenAIRE

Rubiana Chamarbagwala; Martin Ranger

2007-01-01

Fertility decline in developing countries may have unexpected demographic consequences. Although lower fertility improves nutrition, health, and human capital investments for surviving children, little is known about the relationship between fertility outcomes and female-male offspring sex-ratios. Particularly in countries with a cultural preference for sons, like India and China, fertility decline may deteriorate the already imbalanced sex-ratios. We use the fertility histories of over 90,00...

Bioremediation: Application of slow-release fertilizers on low-energy shorelines

International Nuclear Information System (INIS)

Lee, K.; Tremblay, G.H.; Levy, E.M.

1993-01-01

In situ biodegradation, the activation of microbial processes capable of destroying contaminants where they are found in the environment, is a biological process that responds rapidly to changing environmental factors. Accordingly, in situ sediment enclosures were used to test the efficacy of selected nutrient formulations to enhance the biodegradation of a waxy crude oil in a low-energy shoreline environment. The addition of soluble inorganic fertilizers (ammonium nitrate and triple superphosphate) and slow-release nutrient formulations (sulfur-coated urea) stimulated microbial activity and prolonged the period of oil degradation, despite a decline in seasonal temperatures. Low temperatures reduced the permeability of the coating on the slow-release fertilizers, effectively suppressing nutrient release. Of the nutrient formulations evaluated, the authors recommend the application of granular slow-release fertilizers (such as sulfur-coated urea) when the overlying water temperatures are above 15 degrees C, and the application of soluble inorganic fertilizers (such as ammonium nitrate) at lower temperatures. Comprehensive analysis of the experimental results indicate that application protocols for bioremediation (form and type of fertilizer or type and frequency of application), be specifically tailored to account for differences in environmental parameters (including oil characteristics) at each contaminated site

Cycling of fertilizer and cotton crop residue nitrogen

International Nuclear Information System (INIS)

Rochester, I.J.; Constable, G.A.; MacLeod, D.A.

1993-01-01

Mineral nitrogen (N), nitrate and ammonium contents were monitored in N-fertilized soils supporting cotton crops to provide information on the nitrification, mineralization and immobilization processes operating in the soil. The relative contributions of fertilizer N, previous cotton crop residue N and indigenous soil N to the mineral N pools and to the current crop's N uptake were calculated. After N fertilizer (urea) application, the soil's mineral N content rose rapidly and subsequently declined at a slower rate. The recovery of 15 N-labelled urea as mineral N declined exponentially with time. Biological immobilization (and possibly denitrification to some extent) were believed to be the major processes reducing post-application soil mineral N content. Progressively less N was mineralized upon incubation of soil sampled through the growing season. Little soil N (either from urea or crop residue) was mineralized at crop maturity. Cycling of N was evident between the soil mineral and organic N pools throughout the cotton growing season. Considerable quantities of fertilizer N were immobilized by the soil micro biomass; immobilized N was remineralized and subsequently taken up by the cotton crop. A large proportion of the crop N was taken up in the latter part of the season when the soil mineral N content was low. It is suggested that much of the N taken up by cotton was derived from microbial sources, rather than crop residues. The application of cotton crop residue (stubble) slightly reduced the mineral N content in the soil by encouraging biological immobilization. 15 N was mineralized very slowly from the labelled crop residue and did not contribute significantly to the supply of N to the current crop. Recovery of labelled fertilizer N and labelled crop residue N by the cotton crop was 28% and 1%, respectively. In comparison, the apparent recovery of fertilizer N was 48%. Indigenous soil N contributed 68% of the N taken up by the cotton crop. 33 refs., 1 tab

Abortion Legalization and Life-Cycle Fertility

Science.gov (United States)

Ananat, Elizabeth Oltmans; Gruber, Jonathan; Levine, Phillip

2007-01-01

The early-1970s abortion legalization led to a significant drop in fertility. We investigate whether this decline represented a delay in births or a permanent reduction in fertility. We combine Census and Vital Statistics data to compare the lifetime fertility of women born in early-legalizing states, whose peak childbearing years occurred in the…

Analysis of Fertility in Ten Central And Eastern European Countries After 1989

Directory of Open Access Journals (Sweden)

Dănuţ-Vasile JEMNA

2014-06-01

Full Text Available The establishment of democracy in the communist countries, which generated profound social and economic transformation, was accompanied by a decline in fertility. We attempt to provide an overall survey on fertility since 1989 in ten Central and Eastern European Countries, members of the European Union, and to identify the variables which explain the fertility decline. We will use univariate and multivariate statistical analysis to identify disparities between the ten countries, and the variables which explain these differences. Also, we developed a panel econometric model to confirm the hypothesis of a similar pattern of evolution for fertility in these countries and that the decline in fertility can be explained both through demographic and economic variables. The decline in fertility can be explained by economic growth, marriage, divorce, abortion, and migration. The empirical evidence presented in this paper supports the view that the decline in fertility over the 1989s represents the continuation of a longstanding trend of the previous period, according to the demographic transition theory, but its speed and magnitude has been influenced by the new social and economic landscape. These results can be useful for public authorities of the CEE countries to rethinking demographic policies and to ensure the sustainability of demographic growth.

Fertility targets and policy options in Asia.

Science.gov (United States)

Bulatao, R A

1984-11-01

The 3rd Asian and Pacific Population Conference in Colombo in 1982 recommended that countries review and modify existing demographic targets and goals for reducing birth and death rates in order to attain low levels as early as possible and to attain replacement level by the year 2000. The demographic goals of selected Asian countries (Bangladesh, Indonesia, Korea, Thailand, India, Pakistan, and the Philippines are assessed and compared to World Bank population projections. It also discusses the underlying rationale for setting fertility targets, and considers what government actions could make them more achievable. 6 stages for controlling population are distinguished: 1) collection and publication of reliable demographic data; 2) enunciation of an official policy to reduce population growth; 3) development of appropriate institutions to integrate demographic projections into economic plans; 4) promotion of family planning; 5) provision of incentives and disincentives, including elimination of all implicit and explicit subsidies for child bearing; and 6) restitution of birth quotas requiring permission for each child born. Principles to maintain and accelerate fertility declines to meet demographic targets include creating appropriate and equitable development policies, increasing the standard of family planning programs, confronting organizational problems, providing easier and more equal access to contraceptive methods, exploring innovative approaches to encourage smaller families and making a firm political commitment to population control. Rapid fertility decline will also require financial commitment. Willingness to spend the necessary amounts, and the capacity to spend them as well, will determine whether the countries of Asia enter the next century in control of their population.

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.

A parsimonious characterization of change in global age-specific and total fertility rates

Science.gov (United States)

2018-01-01

This study aims to understand trends in global fertility from 1950-2010 though the analysis of age-specific fertility rates. This approach incorporates both the overall level, as when the total fertility rate is modeled, and different patterns of age-specific fertility to examine the relationship between changes in age-specific fertility and fertility decline. Singular value decomposition is used to capture the variation in age-specific fertility curves while reducing the number of dimensions, allowing curves to be described nearly fully with three parameters. Regional patterns and trends over time are evident in parameter values, suggesting this method provides a useful tool for considering fertility decline globally. The second and third parameters were analyzed using model-based clustering to examine patterns of age-specific fertility over time and place; four clusters were obtained. A country’s demographic transition can be traced through time by membership in the different clusters, and regional patterns in the trajectories through time and with fertility decline are identified. PMID:29377899

Does fertility decrease household consumption?

OpenAIRE

Jungho Kim; Henriette Engelhardt; Alexia Fürnkranz-Prskawetz; Arnstein Aassve

2009-01-01

This paper presents an empirical analysis of the relationship between fertility and a direct measure of poverty for Indonesia, a country, which has experienced unprecedented economic growth and sharp fertility declines over recent decades. It focuses on illustrating the sensitivity of the effect of fertility on household consumption with respect to the equivalence scale by applying the propensity score matching method. The analysis suggests that a newborn child decreases household consumption...

Impacts of land use and Ugandan farmer's cultural and economic status on soil organic matter and soil fertility

Science.gov (United States)

Tiemann, Lisa; Grandy, Stuart; Hartter, Joel

2014-05-01

Soil is the keystone in building sustainable agricultural systems, but increased demand for these soil services has led to soil degradation, particularly in sub-Saharan Africa. In Uganda, where population growth rates are 9th highest in the world, increasing pressure on soil resources and potential losses of SOM are particularly concerning because there is virtually no use of fertilizers or other inputs on farms. In addition, smallholder farmers in Uganda are placing greater emphasis on resource-intensive cash crops like maize, and thereby straining soil resources. In this study we investigate the relationships between land use decisions and soil fertility to better understand declines in soil fertility and how they might be slowed near Kibale National Park (KNP), Uganda, a global biodiversity hotspot. Within 2.5 km of the KNP border, we conducted household surveys and collected soil samples in 160 farms along a 20 km north-south transect. We also collected soils from inside KNP, adjacent to farms we visited, to serve as controls. Cultural differences in land use, such as greater residue removal and a lower likelihood of legumes in rotation with the Bakiga, likely led to the greater declines in SOM and soil fertility we observed in Bakiga compared to Batooro maize fields. We also found that households in areas of high soil fertility are more reliant on maize sales. Surprisingly, these same areas have also seen relatively smaller declines in total SOM, but do show larger relative declines in nutrients (e.g. N, P and K) when compared to the adjacent KNP soils. We found lower depletion of nutrients and overall higher soil fertility measures and more stability of SOM in banana fields compared to maize fields, which is due to transferring maize crop residues to banana plantations as well as no-till practices in banana fields. Our work reveals that complex interactions between edaphic soil properties, land use management, cultural background, perceptions of soil

Correlations in fertility across generations: can low fertility persist?

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Kolk, Martin; Cownden, Daniel; Enquist, Magnus

2014-01-01

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. PMID:24478294

Rapid Evolution of Assortative Fertilization between Recently Allopatric Species of Drosophila.

Science.gov (United States)

Ahmed-Braimah, Yasir H; McAllister, Bryant F

2012-01-01

The virilis group of Drosophila represents a relatively unexplored but potentially useful model to investigate the genetics of speciation. Good resolution of phylogenetic relationships and the ability to obtain fertile hybrid offspring make the group especially promising for analysis of genetic changes underlying reproductive isolation separate from hybrid sterility and inviability. Phylogenetic analyses reveal a close relationship between the sister species, Drosophila americana and D. novamexicana, yet excepting their contemporary allopatric distributions, factors that contribute to reproductive isolation between this species pair remain uncharacterized. A previous report has shown reduced progeny numbers in laboratory crosses between the two species, especially when female D. novamexicana are crossed with male D. americana. We show that the hatch rate of eggs produced from heterospecific matings is reduced relative to conspecific matings. Failure of eggs to hatch, and consequent reduction in hybrid progeny number, is caused by low fertilization success of heterospecific sperm, thus representing a postmating, prezygotic incompatibility. Following insemination, storage and motility of heterospecific sperm is visibly compromised in female D. novamexicana. Our results provide evidence for a mechanism of reproductive isolation that is seldom reported for Drosophila species, and indicate the rapid evolution of postmating, prezygotic reproductive barriers in allopatry.

Fertility change in the American Indian and Alaska Native population, 1980-2010

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Sarah Cannon

2017-07-01

Full Text Available Background: Since 1990, Vital Statistics reports show a dramatic decline in the total fertility rates (TFRs of American Indian and Alaska Native (AI/AN women in the United States. Objective: We study whether the decrease in TFRs is due to a real change in fertility for a stable population; a compositional change in who identifies as AI/AN; or a methodological issue stemming from differences in identifying race across the data systems used to calculate fertility rates. Methods: We use data from the decennial US Census to study change in AI/AN fertility from 1980-2010. Results: We find declining TFRs when fertility is calculated within a single data system. Additionally, although TFRs are relatively stable within the subgroups of married and unmarried AI/AN women, the proportion of AI/AN women who are married has declined across birth cohorts. Conclusions: The decrease in TFRs for AI/AN women is a real change in fertility patterns and is not due to differences in racial identification across data systems. Contribution: We update knowledge of AI/AN fertility to include the decline in TFRs between 1980 and 2010.

Changing fertility patterns and policies in the third world.

Science.gov (United States)

Mcnicoll, G

1992-01-01

Different patterns of fertilty transition are apparent in developing countries. Theories of fertility decline are appropriate because demographic analysis has become situation specific rather than general. Pretransition fertility patterns and the onset of decline are provided. Fertility transition patterns are also supplied, including a regional overview for Latin America, east and Southeast Asia, South Asia, West Asia and North Africa, and sub-Saharan Africa. The specialized cases of China, India, Bangladesh, Thailand and Indonesia, and Brazil are also presented. The fertility determinant models of Bongaarts, Davis and Blake, Hobcraft and Little, Ryder, and Henry are used as examples of proximate determinant models. Data collection was possible on a grand scale with contraceptive knowledge, attitudes, and practice (KAP) surveys and the World Fertility Surveys and Demographic and Health Surveys. Criticism has focused on the scope of these surveys which provide at best proximate determinants and differentiate fertility by standard socioeconomic factors. Data are also obtained on small populations from piecing together records and from quasi-anthropological fieldwork. Historical demography relies on family reconstitution. Longitudinal studies are few in number. The largest and most effective fieldwork station is at Matlab in Bangladesh. Caldwell has provided anthropological methods applicable to fertility study and makes use of teamwork. In Latin America, fertility has fallen by 40% since the 1960s. Bolivia, Guatemala, Honduras, Nicaragua, El Salvador, and Haiti have changed very little. Taiwan and South Korea provide examples of economic growth with equity in East and Southeast Asia. In heterogenous South Asia, decline has been slow and uneven. West Asia and North Africa have high fertility with the exception of Egypt which is in the early stages of transition. The smallest declines are found in sub-Saharan Africa, and are complicated by the AIDS epidemic.

Marriage and fertility in the developed countries.

Science.gov (United States)

Westoff, C F

1978-12-01

Most developed countries have reached zero population growth or less and, while population projections have often proved badly off-target, it seems that currently low fertility levels are the result of a long-term trend, which was interrupted in the last 100 years only by the still-unexplained postwar baby boom, and which will probably continue. The declining trend has accompanied economic development and modernization, which have transformed the economic value of children, making them a drain on resources rather than a source of income. The concomitant social changes seem largely irreversible: urban economy, the decline in traditional authority, universal, prolonged education, equality of women, low infant mortality, high consumer demands and sophisticated birth control technology are all here to stay. The theory that fertility exhibits a cyclical pattern based on people's perception of their degree of economic and social opportunity ignores the other elements affecting fertility behavior, especially the radical change in the status and expectations of women. Several trends in marriage and reproductive behavior in the U.S., Denmark and Sweden reinforce the presumption that fertility will remain low: declining number of marriages; postponement of marriage; increased tendency for unmarried couples to live together; instability of marriage shown by high divorce rates and declining remarriage rates; and increasing economic activity by women. The traditional institution of marriage is losing its economic, sexual, sociological and parenting rationales. Thus, declining fertility is both cause and consequence of changes in marriage. In Europe, where the decline is more advanced than in the U.S., governments are concerned that population growth will be too low and have instituted social welfare measures to induce and facilitate childbearing and childrearing. As women become more career-oriented, greater incentives will have to be provided. Manipulating immigration quotas

Structural modeling of age specific fertility curves in Peninsular Malaysia: An approach of Lee Carter method

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Hanafiah, Hazlenah; Jemain, Abdul Aziz

2013-11-01

In recent years, the study of fertility has been getting a lot of attention among research abroad following fear of deterioration of fertility led by the rapid economy development. Hence, this study examines the feasibility of developing fertility forecasts based on age structure. Lee Carter model (1992) is applied in this study as it is an established and widely used model in analysing demographic aspects. A singular value decomposition approach is incorporated with an ARIMA model to estimate age specific fertility rates in Peninsular Malaysia over the period 1958-2007. Residual plots is used to measure the goodness of fit of the model. Fertility index forecast using random walk drift is then utilised to predict the future age specific fertility. Results indicate that the proposed model provides a relatively good and reasonable data fitting. In addition, there is an apparent and continuous decline in age specific fertility curves in the next 10 years, particularly among mothers' in their early 20's and 40's. The study on the fertility is vital in order to maintain a balance between the population growth and the provision of facilities related resources.

Social structure, contraceptive availability, and Black fertility decline in Mmabatho / Mafikeng in the Northwest region.

Science.gov (United States)

Amoateng, A Y

1994-10-01

Data were obtained from a survey of clients of family planning clinics in the city of Mmabatho/Mafikeng, Bophuthatswana, which was undertaken in 1992-93. 500 Black female clients were interviewed at four government and two family planning clinics between June 1992 and February 1993 regarding the practice of family planning and the formation and dissolution of families. There was a clear tendency for women to have small families, especially urban residents. They averaged 1.5 children. In addition, there was a drastic intergenerational fertility decline of 72.85% compared with their mothers. There was a positive association between age and fertility: women aged 34-52 had a mean of 3.85 children ever born, while the mean number of children was 0.50 for women aged 14-23. Education was negatively associated with fertility even when socioeconomic factors were controlled for, as women with more than middle school education had fewer children than their counterparts with education up to middle school. Women earning over R1000/month had an average of 0.75 fewer children than women who earned below R1000/month. Single, never married women had the fewest number of children ever born, followed by those who were cohabiting. Women who were widowed had the highest mean number of children ever born (3.50), followed by women currently in their first marriages (2.83) and those who were remarried (2.75). Women adhering to traditional African religions had the highest number of children ever born (2.20), followed by believers of the Zionist, Apostolic, and other Pentecostal churches. The knowledge of contraception was negatively associated with the number of children ever born. The injection (99.6%), the pill (95.4%), and the condom (90.1%) were the three most commonly known methods, while vaginal methods (20.6%) and the rhythm method (24.4%) were the least known. There is clear evidence that in African societies transformations are taking place in the family.

Computational identification of fertility functions of bovine Reprimo ...

African Journals Online (AJOL)

Improvement in fertility is possible through gene assisted selection. Cattle fertility and genes underlying it should be thoroughly studied and exploited to find solution to declining cattle fertility. Reprimo (RPRM) gene is a pleiotropic gene involved in suppression of cancer, regulation of mitotic cell cycle, cell cycle arrest and ...

The need to improve fertility awareness

Directory of Open Access Journals (Sweden)

Joyce Harper

2017-06-01

Full Text Available Women and men globally are delaying the birth of their first child. In the UK, the average age of first conception in women is 29 years. Women experience age-related fertility decline so it is important that men and women are well-informed about this, and other aspects of fertility. A group of UK stakeholders have established the Fertility Education Initiative to develop tools and information for children, adults, teachers, parents and healthcare professionals dedicated to improving knowledge of fertility and reproductive health.

Socioeconomic 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

2016-01-01

We have good knowledge of the timing of the historical fertility transitions in different regions, but we know much less regarding specific features and causes. In this study, we used longitudinal micro-level data for five local populations in Europe and North America to study the relationship between socioeconomic status and fertility during the transition. Using the same analytical model and identical class scheme, we examined the development of socioeconomic differences in marital fertility and related it 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 support the idea that they acted as forerunners in the transition by reducing their fertility before other groups. Farmers and unskilled workers were latest to start to limit their fertility. Apart from this regularity, the patterns of class differences in fertility varied significantly among populations. PMID:27884093

Polar bear and walrus response to the rapid decline in Arctic sea ice

Science.gov (United States)

Oakley, K.; Whalen, M.; Douglas, David C.; Udevitz, Mark S.; Atwood, Todd C.; Jay, C.

2012-01-01

The Arctic is warming faster than other regions of the world due to positive climate feedbacks associated with loss of snow and ice. One highly visible consequence has been a rapid decline in Arctic sea ice over the past 3 decades - a decline projected to continue and result in ice-free summers likely as soon as 2030. The polar bear (Ursus maritimus) and the Pacific walrus (Odobenus rosmarus divergens) are dependent on sea ice over the continental shelves of the Arctic Ocean's marginal seas. The continental shelves are shallow regions with high biological productivity, supporting abundant marine life within the water column and on the sea floor. Polar bears use sea ice as a platform for hunting ice seals; walruses use sea ice as a resting platform between dives to forage for clams and other bottom-dwelling invertebrates. How have sea ice changes affected polar bears and walruses? How will anticipated changes affect them in the future?

Age shock: misperceptions of the impact of age on fertility before and after IVF in women who conceived after age 40.

Science.gov (United States)

Mac Dougall, K; Beyene, Y; Nachtigall, R D

2013-02-01

What do older women understand of the relationship between age and fertility prior and subsequent to delivering their first child? Women who were first-time parents over the age of 40 did not accurately perceive the relationship between age and fertility prior to conceiving with IVF. While increases in women's age at their first birth have been most pronounced in relatively older women, the rapidity of fertility decline is not appreciated by most non-infertility specialist physicians, the general public or men and women who are delaying childbearing. Qualitative retrospective interviews were conducted from 2009 to 2011 with 61 self-selected women who were patients in one of two fertility clinics in the USA. All participants had delivered their first child following IVF when the woman was 40 years or older. The data include women's responses to the semi-structured and open-ended interview questions 'What information did you have about fertility and age before you started trying to get pregnant?' and 'What did you learn once you proceeded with fertility treatment?' Of the women, 30% expected their fertility to decline gradually until menopause at around 50 years and 31% reported that they expected to get pregnant without difficulty at the age of 40. Reasons for a mistaken belief in robust fertility included recollections of persistent and ongoing messaging about pregnancy prevention starting in adolescence (23%), healthy lifestyle and family history of fertility (26%), and incorrect information from friends, physicians or misleading media reports of pregnancies in older celebrity women (28%). Participants had not anticipated the possibility that they would need IVF to conceive with 44% reporting being 'shocked' and 'alarmed' to discover that their understanding of the rapidity of age-related reproductive decline was inaccurate'. In retrospect, their belated recognition of the effect of age on fertility led 72% of the women to state that they felt 'lucky' or had

Development policy and the projects for fertility decline in Bangladesh.

Science.gov (United States)

Cain, M; Lieberman, S S

1983-09-01

This paper reviews Bangladesh's government policy and suggests which development measures other than family planning services would increase contraceptive usage. It develops a framework for policy analysis by reviewing the fertility determinants literature in general, and that on Bangladesh. Conventional approaches, based on demographic transition theory (which presupposes economic development in the Third World will follow the historical path of the West, with attendant rates of urbanization and industrialization) and the microeconomic theory of consumer choice (whereby costs of children are measured only in the context of the internal workings of the household without regard to outside influences) are rejected in favor of an institutional framework, which emphasizes the productive value of children in the context of the institutional underpinnings of the costs and benefits of children. The analysis identifies the extremely harsh environment of risk, and the absence of effective forms of risk insurance, as crucial to understanding the persistence of Bangladesh's high fertility. It concludes that to ensure the country's fertility transition, the positive reproductive incentive associated with children as insurance against risk must be eliminated or reduced. Therefore policies with the greatest impact on reproductive behavior would either alter the environment of risk or introduce other effective means of adjusting to risk. Among the components of the development program in the Second Five Year Plan, rural public employment measures hold the greatest promise for reducing fertility. Such current initiatives have had program limitations, such as relief rather than long-term orientation and bottlenecks in communication and transportation. However, these efforts form a basis for developing a policy of guaranteed public works employment. This policy's potential flexibility, broad base, and success in other parts of South Asia (particularly Maharashtra State, India) make

Improving family planning services delivery and uptake: experiences from the "Reversing the Stall in Fertility Decline in Western Kenya Project".

Science.gov (United States)

Amo-Adjei, Joshua; Mutua, Michael; Athero, Sherine; Izugbara, Chimaraoke; Ezeh, Alex

2017-10-10

In this paper, we reflect on our experiences of implementing a multipronged intervention to improve sexual and reproductive health outcomes. The project used family planning as its entry point and was implemented in two high fertility counties-Busia and Siaya in Kenya. The intervention, implemented by a seven-member consortium, involved: family planning services delivery; regular training of service providers to deliver high quality services; monitoring and evaluation; strengthening of commodity chain delivery and forecasting; school-based and out-of-school based sexuality education; and advocacy and stakeholder engagements at the community, county and national levels. Over a 5-year period, the project contributed to raising demand for family planning considerably, evidenced in fertility decline. It also improved the capacity of family planning services providers, increased commitment and awareness of county government and other community stakeholders on the importance of investments in family planning. Our collaborations with organisations interested in sexual and reproductive health issues substantially enhanced the consortium's ability to increase demand for, and supply of family planning commodities. These collaborations are proving useful in the continuity and sustainability of project achievements.

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).

Additional pest surveyed: hickory decline

Science.gov (United States)

Jennifer Juzwik; Ji-Hyun. Park

2011-01-01

A five year investigation of the cause of rapid crown decline and mortality of bitternut hickory was concluded in September 2011. Results of a series of related studies found that multiple cankers and xylem (the water conducting tissue) dysfunction caused by Ceratocystis smalleyi are correlated with rapid crown decline typical of a limited vascular...

Unrealized fertility: Fertility desires at the end of the reproductive career

Directory of Open Access Journals (Sweden)

John Casterline

2017-01-01

Full Text Available Background: 'Unrealized fertility' is a failure to achieve desired fertility. Unrealized fertility has been examined in low-fertility societies but, with the exception of research on infertility, has been neglected in research on non-Western societies. Objective: We conduct a multicountry investigation of one form of unrealized fertility, namely a reproductive career which ends with the woman desiring further children. Methods: We analyze 295,854 women aged 44‒48 in 252 surveys (DHS, RHS, PAP conducted in the period 1986-2015 in 78 countries. Two indicators of unrealized fertility are constructed: (i a comparison of ideal versus actual number of children; (ii the desire for another child. We estimate multilevel regressions with covariates at individual and aggregate levels. Results: Unrealized fertility is far more prevalent according to the first indicator than the second. It is more common among women with fewer living children and women whose first birth occurs after age 20, and it is distinctly higher in sub-Saharan Africa and lower in South Asia. The evidence on trend over the course of fertility transition is mixed: for the second indicator but not the first, the net effect is a reduction in the prevalence of unrealized fertility as fertility declines. Conclusions: Unrealized fertility occurs frequently in most societies and therefore deserves more rigorous research, especially on its consequences for emotional, social, economic, and demographic outcomes. Contribution: We provide the first comprehensive documentation of the prevalence of unrealized fertility across a broad set of contemporary non-Western societies.

Increasing awareness of age-related fertility and elective fertility preservation among medical students and house staff: a pre- and post-intervention analysis.

Science.gov (United States)

Anspach Will, Erica; Maslow, Bat-Sheva; Kaye, Leah; Nulsen, John

2017-05-01

To assess medical students' and house staff's knowledge and personal and professional perceptions of age-related fertility and fertility preservation before and after an educational intervention. Pre-/post intervention survey. University-based medical center. Medical students and house staff. An educational session on age-related fertility decline and elective fertility preservation. Knowledge scores and perceptions assessed immediately before and after the intervention. Sixty-five surveys were administered. Of the 53 respondents, 71.7% were married or in a committed relationship; 89.4% reported that they were delaying childbearing, with career and/or education being the most frequently listed reason (85.7%); 39.5% indicated that they had both personal and professional interest in fertility preservation but identified finances (62.5%) and time (59.4%) as barriers; 86.9% indicated previous exposure, with formal education (80.0%) and social media (40.0%) being the most common sources. Mean scores on a six-question knowledge-based assessment improved significantly following the presentation (54.6 ± 19.0% vs. 78.1 ± 16.0%), as did the number of participants who indicated that they might now recommend elective oocyte cryopreservation to others (71.1% vs. 54.3%). After the intervention, 97.8% thought that it was important for medical professionals to be informed about age-related fertility decline and elective oocyte cryopreservation. Despite professional and personal interest, knowledge of age-related fertility decline and elective fertility preservation is limited among medical students and house staff. This study highlights the need for formal education across all levels of training and specialties, with even brief interventions being of potential benefit. Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Conference considers low fertility.

Science.gov (United States)

1997-01-01

At present, at least 51 countries--representing 44% of the world's population--are showing below-replacement fertility rates. In some of these countries, where the number of new births is not adequate to replace aging populations, this trend is problematic. In other countries, most notably China, declining fertility has conferred significant benefits. At an Economic and Social Commission for Asia and the Pacific (ESCAP) Population Commission meeting held in New York in 1997, staff from China's State Statistical Bureau reported the country has a current total fertility rate of 1.8. The birth rate remains high, however, because of the large numbers of Chinese women in the 15-49 year reproductive age group (336 million in 1997). Also buffering the impact of a low fertility rate is a large labor surplus (130 million excess workers in rural China). To keep fertility below the replacement level, China plans to improve the quality of its family planning service, enhance poverty alleviation programs, and increase incentives for small families in rural areas. China's low fertility rate has provided an important impetus for economic development.

Disruptive Events and Demographic Behaviour : Explaining the Shifts in Fertility in Rwanda

NARCIS (Netherlands)

Rutayisire, P.C.

2015-01-01

The fertility transition of Rwanda stagnated between 1992 and 2005 at a total fertility rate (TFR) of 6 children per woman. After 2005 the fertility decline resumed its course and the TFR dropped remarkably fast till 4.6. The period of the fertility stall coincided with a very disruptive period in

Globalization and Contemporary Fertility Convergence.

Science.gov (United States)

Hendi, Arun S

2017-09-01

The rise of the global network of nation-states has precipitated social transformations throughout the world. This article examines the role of political and economic globalization in driving fertility convergence across countries between 1965 and 2009. While past research has typically conceptualized fertility change as a country-level process, this study instead employs a theoretical and methodological framework that examines differences in fertility between pairs of countries over time. Convergence in fertility between pairs of countries is hypothesized to result from increased cross-country connectedness and cross-national transmission of fertility-related schemas. I investigate the impact of various cross-country ties, including ties through bilateral trade, intergovernmental organizations, and regional trade blocs, on fertility convergence. I find that globalization acts as a form of social interaction to produce fertility convergence. There is significant heterogeneity in the effects of different cross-country ties. In particular, trade with rich model countries, joint participation in the UN and UNESCO, and joining a free trade agreement all contribute to fertility convergence between countries. Whereas the prevailing focus in fertility research has been on factors producing fertility declines, this analysis highlights specific mechanisms-trade and connectedness through organizations-leading to greater similarity in fertility across countries. Globalization is a process that propels the spread of culturally laden goods and schemas impinging on fertility, which in turn produces fertility convergence.

Own-Choice Marriage and Fertility in Turkey.

Science.gov (United States)

Manglos-Weber, Nicolette D; Weinreb, Alexander A

2017-04-01

Goode's foundational work on the fertility transition identified own-choice marriage as a factor driving fertility decline, part of a widening repertoire of choice pertaining to marriage and childbearing. Yet research supporting this connection in today's transitional societies is scarce and somewhat contradictory, and it is unclear how other marital traditions, such as consanguineous marriage, shape this relationship. This study evaluates Goode's theorized connection using pooled Demographic and Health Survey data from Turkey, comparing children ever born, use of contraception, and parity progression across four types of marriage: own-choice and arranged marriage; and marriage to a cousin versus an unrelated spouse. Results are largely consistent with the idea that a move towards own-choice marriage reflects a widening repertoire of choice that also leads to fertility decline. However, they also show that hybrid models like own-choice marriage to a cousin tempers these effects.

Own-Choice Marriage and Fertility in Turkey

Science.gov (United States)

Weinreb, Alexander A.

2016-01-01

Goode’s foundational work on the fertility transition identified own-choice marriage as a factor driving fertility decline, part of a widening repertoire of choice pertaining to marriage and childbearing. Yet research supporting this connection in today’s transitional societies is scarce and somewhat contradictory, and it is unclear how other marital traditions, such as consanguineous marriage, shape this relationship. This study evaluates Goode’s theorized connection using pooled Demographic and Health Survey data from Turkey, comparing children ever born, use of contraception, and parity progression across four types of marriage: own-choice and arranged marriage; and marriage to a cousin versus an unrelated spouse. Results are largely consistent with the idea that a move towards own-choice marriage reflects a widening repertoire of choice that also leads to fertility decline. However, they also show that hybrid models like own-choice marriage to a cousin tempers these effects. PMID:28316343

Understanding variation in human fertility: what can we learn from evolutionary demography?

Science.gov (United States)

Sear, Rebecca; Lawson, David W; Kaplan, Hillard; Shenk, Mary K

2016-04-19

Decades of research on human fertility has presented a clear picture of how fertility varies, including its dramatic decline over the last two centuries in most parts of the world. Why fertility varies, both between and within populations, is not nearly so well understood. Fertility is a complex phenomenon, partly physiologically and partly behaviourally determined, thus an interdisciplinary approach is required to understand it. Evolutionary demographers have focused on human fertility since the 1980s. The first wave of evolutionary demographic research made major theoretical and empirical advances, investigating variation in fertility primarily in terms of fitness maximization. Research focused particularly on variation within high-fertility populations and small-scale subsistence societies and also yielded a number of hypotheses for why fitness maximization seems to break down as fertility declines during the demographic transition. A second wave of evolutionary demography research on fertility is now underway, paying much more attention to the cultural and psychological mechanisms underpinning fertility. It is also engaging with the complex, multi-causal nature of fertility variation, and with understanding fertility in complex modern and transitioning societies. Here, we summarize the history of evolutionary demographic work on human fertility, describe the current state of the field, and suggest future directions. © 2016 The Author(s).

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.

Influence of fertilizer draw solution properties on the process performance and microbial community structure in a side-stream anaerobic fertilizer-drawn forward osmosis - ultrafiltration bioreactor.

Science.gov (United States)

Kim, Youngjin; Li, Sheng; Chekli, Laura; Phuntsho, Sherub; Ghaffour, Noreddine; Leiknes, TorOve; Shon, Ho Kyong

2017-09-01

In this study, a side-stream anaerobic fertilizer-drawn forward osmosis (FDFO) and ultrafiltration (UF) membrane bioreactor (MBR) hybrid system was proposed and operated for 55days. The FDFO performance was first investigated in terms of flux decline with various fertilizers draw solution. Flux decline was very severe with all fertilizers due to the absence of aeration and the sticky property of sludge. Flux recovery by physical cleaning varied significantly amongst tested fertilizers which seriously affected biofouling in FDFO via reverse salt flux (RSF). Besides, RSF had a significant impact on nutrient accumulation in the bioreactor. These results indicated that nutrient accumulation negatively influenced the anaerobic activity. To elucidate these phenomena, bacterial and archaeal community structures were analyzed by pyrosequencing. Results showed that bacterial community structure was affected by fertilizer properties with less impact on archaeal community structure, which resulted in a reduction in biogas production and an increase in nitrogen content. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

Knowledge about factors that influence fertility among Australians of reproductive age: a population-based survey.

Science.gov (United States)

Hammarberg, Karin; Setter, Tracey; Norman, Robert J; Holden, Carol A; Michelmore, Janet; Johnson, Louise

2013-02-01

To explore knowledge about the effects on fertility of age, obesity, smoking, and timing of intercourse among Australians of reproductive age. Telephone survey of a representative sample of Australians. Not applicable. Australians aged 18 to 45 years who wish to have a child or another child now or in the future. None. Knowledge about the effect on fertility of age, obesity, smoking, and timing of intercourse. A total of 462 interviews were conducted. The majority of respondents underestimated, by about 10 years, the age at which male and female fertility starts to decline. Only one in four correctly identified that female fertility starts to decline before age 35, and one in three identified that male fertility starts to decline before age 45. Most (59%) were aware that female obesity and smoking affect fertility, but fewer recognized that male obesity (30%) and smoking (36%) also influence fertility. Almost 40% of respondents had inadequate knowledge of when in the menstrual cycle a woman is most likely to conceive. Considerable knowledge gaps about modifiable factors that affect fertility were identified. These are targeted in a national education campaign to promote awareness of factors that influence fertility. Copyright © 2013 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Poor semen quality may contribute to recent decline in fertility rates

DEFF Research Database (Denmark)

Jensen, Tina Kold; Carlsen, Elisabeth; Jørgensen, Niels

2002-01-01

may not be attributable to social factors, changes in conception practices or diminished sexual activity alone. It seems reasonable also to consider widespread poor semen quality among men as a potential contributing factor to low fertility rates among teenagers. Due to the concern caused by the low...... sperm count among younger Danish men, the Danish Ministries of Health and Environment have launched a surveillance programme which includes an annual examination of the semen quality in 600 young Danes from the general population. We propose that researchers in other countries with low and falling...... fertility rates among young women should consider the possibility that semen quality of their younger male cohorts may also have deteriorated....

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.

Constant mortality and fertility over age in Hydra

DEFF Research Database (Denmark)

Schaible, R.; Scheuerlein, A.; Danko, M. J.

2015-01-01

that 2,256 Hydra from two closely related species in two laboratories in 12 cohorts, with cohort age ranging from 0 to more than 41 y, have extremely low, constant rates of mortality. Fertility rates for Hydra did not systematically decline with advancing age. This falsifies the universality......Senescence, the increase in mortality and decline in fertility with age after maturity, was thought to be inevitable for all multicellular species capable of repeated breeding. Recent theoretical advances and compilations of data suggest that mortality and fertility trajectories can go up or down......, or remain constant with age, but the data are scanty and problematic. Here, we present compelling evidence for constant age-specific death and reproduction rates in Hydra, a basal metazoan, in a set of experiments comprising more than 3.9 million days of observations of individual Hydra. Our data show...

Fertility trends in Singapore.

Science.gov (United States)

Singh, K; Viegas, O; Ratnam, S S

1988-10-01

In 1966, the Singapore National Family Planning and Population Program established the goal of reaching replacement fertility by 1990 and zero population growth by the year 2030. To achieve this goal, the government relied on a series of incentives and disincentives to discourage births above the 3rd birth order, including tax relief for the 1st 3 children only, paid medical leave for women undergoing sterilization after the 3rd or subsequent birth, monetary stipends in some cases where the mother is sterilized after the 1st or 2nd birth, and increasing accouchement charges for increasing birth orders. Also important to demographic planning were liberalization of Singapore's abortion legislation and more aggressive promotion of contraception. As a result of these efforts, Singapore's crude birth rate has declined from 29.5/1000 population in 1965 to 16.6/1000 in 1985. Also observed have been dramatic declines in infant mortality in this same period, from 26.2/1000 live births to 9.3/1000, and in maternal mortality, from 52/100,000 live births to 10/100,000. In 1985, 42% of total births were to women in the 25-29-year age group. The numbers of 4th and later births fell by 90% between 1966 and 1985. The total fertility rate has declined from 4.6/woman in 1965 to 3.1 in 1970 to 1.6 in 1986. Below replacement level fertility was achieved in 1975, in part because of government policy but also as a result of cultural and socioeconomic factors such as increasing female labor force participation rates, a break-up of the extended family system, a rise in the age at 1st marriage, and rises in educational attainment. The drop in fertility was contributed mainly by the higher socioeconomic class, more affluent, and educated Singaporeans. Thus, in 1981, the government introduced certain pronatalist policies and incentives to encourage better educated women to produce more children, e.g., tax relief and the elimination of monetary incentives to sterilization acceptors above a

Knowledge, attitudes, and intentions toward fertility awareness and oocyte cryopreservation among obstetrics and gynecology resident physicians.

Science.gov (United States)

Yu, L; Peterson, B; Inhorn, M C; Boehm, J K; Patrizio, P

2016-02-01

What knowledge, attitudes and intentions do US obstetrics and gynecology (OB/GYN) residents have toward discussing age-related fertility decline and oocyte cryopreservation with their patients? Most OB/GYN residents believe that age-related fertility decline, but not oocyte cryopreservation, should be discussed during well-woman annual exams; furthermore, nearly half of residents overestimated the age at which female fertility markedly declines. Oocyte cryopreservation can be utilized to preserve fertility potential. Currently, no studies of US OB/GYN residents exist that question their knowledge, attitudes, and intentions toward discussing age-related fertility decline and oocyte cryopreservation with patients. A cross-sectional online survey was conducted during the fall of 2014 among residents in American Council for Graduate (ACOG) Medical Education-approved OB/GYN residency programs. Program directors were emailed via the ACOG Council on Resident Education in Obstetrics and Gynecology server listing and asked to solicit resident participation. Participants included 238 residents evenly distributed between post-graduate years 1-4 with varied post-residency plans; 90% of residents were women and 75% were 26-30 years old. The survey was divided into three sections: demographics, fertility awareness, and attitudes toward discussing fertility preservation options with patients. Descriptive and inferential statistics were conducted. A strong majority of residents (83%) believed an OB/GYN should initiate discussions about age-related fertility decline with patients (mean patient age 31.8), and 73% percent believed these discussions should be part of an annual exam. One third of residents overestimated the age at which there is a slight decline in female fertility, while nearly half of residents overestimated the age at which female fertility markedly declines. Over three-quarters of residents (78.4%) also overestimated the likelihood of success using assisted

Influence of fertilizer draw solution properties on the process performance and microbial community structure in a side-stream anaerobic fertilizer-drawn forward osmosis – ultrafiltration bioreactor

KAUST Repository

Kim, Youngjin

2017-02-27

In this study, a side-stream anaerobic fertilizer-drawn forward osmosis (FDFO) and ultrafiltration (UF) membrane bioreactor (MBR) hybrid system was proposed and operated for 55 days. The FDFO performance was first investigated in terms of flux decline with various fertilizers draw solution. Flux decline was very severe with all fertilizers due to the absence of aeration and the sticky property of sludge. Flux recovery by physical cleaning varied significantly amongst tested fertilizers which seriously affected biofouling in FDFO via reverse salt flux (RSF). Besides, RSF had a significant impact on nutrient accumulation in the bioreactor. These results indicated that nutrient accumulation negatively influenced the anaerobic activity. To elucidate these phenomena, bacterial and archaeal community structures were analyzed by pyrosequencing. Results showed that bacterial community structure was affected by fertilizer properties with less impact on archaeal community structure, which resulted in a reduction in biogas production and an increase in nitrogen content.

soil fertility management practices by smallholder farmers in vhembe ...

African Journals Online (AJOL)

p2333147

constraints associated with soil fertility management practices used by the farmers. ... nutrients. In addition, these drier areas often have highly degradable soils that are susceptible to soil erosion and eventual decline in soil fertility, especially under ... cases where the selected farm was a “community garden” (a group of.

Agricultural growth, the status of women, and fertility.

Science.gov (United States)

Whittington, L A; Stapleton, D C

1995-08-01

This study tests the hypothesis that fertility is affected differently by economic growth depending upon the specific sector (agriculture, manufacturing, heavy industry, and services) where growth occurred. The hypothesis is that fertility responses are not identical across sectors. The sample includes 51 World Bank member countries in varying stages of development. The econometric model pertains to 1965-88 and the percentage change in the total fertility rate (TFR). During the study period the average TFR declined by over 22%, but the extent of change varied by country and included, for instance, countries such as Ethiopia that experienced fertility increases from 5.8 to 6.5. Hong Kong's TFR declined by 66% from 4.7 to 1.6. Analysis included measures of changes in gross domestic product (GDP) for each of the four sectors and change in real per capita exports in agricultural commodities, resources, and manufactured products. Changes in educational status and changes in infant mortality were also included in some models. There were mixed results for the impact of total GDP. Sectoral analysis shows a positive, small significant impact on TFR from changes in the GDP per capita in agriculture (domestic and export products), and a negative, small significant impact from manufacturing growth. Heavy industry and services produced insignificant impact. In the model with only domestic consumption, results show a stronger coefficient and continued significance for agricultural productivity, agricultural exports, and manufacturing changes per capita. Manufacturing exports produced a negative, insignificant impact. The null hypothesis is rejected only in models comparing aggregate GDP in agriculture and manufacturing industries plus control variables (excluding heavy industry and services). Only secondary education was a negative, significant determinant of fertility. Infant mortality was insignificant when sectoral growth and education were included in the model. The evidence

Fertility trends and net reproduction in Agincourt, rural South Africa, 1992-2004.

Science.gov (United States)

Garenne, Michel L; Tollman, Stephen M; Collinson, Mark A; Kahn, Kathleen

2007-08-01

To analyse trends in fertility rates and net reproduction rates in Agincourt, a rural area of South Africa located in the former homeland of Gazankulu near the Mozambican border. Trends are analysed in the context of widely available modern contraceptive methods and increasing HIV/AIDS. A health and demographic surveillance system has been in place since 1992, covering a population of approximately 70,000 persons, with an annual census update and comprehensive recording of births and deaths. It was complemented by a retrospective study of fertility at baseline. Retrospective and prospective data were used to calculate trends in fertility, survival, and net reproduction. When possible, they were compared with data from other censuses and surveys in the same ethnic group. The fertility transition has almost ended over a course of 25 years in Agincourt. The total fertility rate (TFR) averaged 6.0 in 1979 and 2.3 in 2004. Fertility declined in proportionate fashion in all age groups including adolescents in the recent period. The net reproduction rate (NRR) declined from 1.8 to 1.0 during the prospective period (1992-2004). At current rates of change in fertility and mortality, the NRR can be expected to reach 0.63 by the year 2010. The situation of a below-replacement fertility level is new for rural Africa, and is likely to have many demographic, economic and social implications. The population could decline in the country as a whole, and is nearly static in Agincourt because of negative migration flows balancing the small excess from natural increase.

Response of Raphia (Raphia Hookeri) Palm Seedlings to Fertilizer ...

African Journals Online (AJOL)

2012r

2014-11-17

Nov 17, 2014 ... UNIVERSITY OF MAURITIUS RESEARCH JOURNAL – Volume 20 – 2014 ... work that no matter how effectively other conditions are met per capita food production in Nigeria will continue to decline unless soil fertility is ... industry is a business venture and therefore the economic value of fertilizer input.

India's Fertilizer Industry: Productivity and Energy Efficiency

Energy Technology Data Exchange (ETDEWEB)

Schumacher, K.; Sathaye, J.

1999-07-01

Historical estimates of productivity growth in India's fertilizer sector vary from indicating an improvement to a decline in the sector's productivity. The variance may be traced to the time period of study, source of data for analysis, and type of indices and econometric specifications used for reporting productivity growth. Our analysis shows that in the twenty year period, 1973 to 1993, productivity in the fertilizer sector increased by 2.3% per annum. An econometric analysis reveals that technical progress in India's fertilizer sector has been biased towards the use of energy, while it has been capital and labor saving. The increase in productivity took place during the era of total control when a retention price system and distribution control was in effect. With liberalization of the fertilizer sector and reduction of subsidies productivity declined substantially since the early 1990s. Industrial policies and fiscal incentives still play a major role in the Indian fertilizer sect or. As substantial energy savings and carbon reduction potential exists, energy policies can help overcome barriers to the adoption of these measures in giving proper incentives and correcting distorted prices.

Three Cell Fusions during Double Fertilization.

Science.gov (United States)

Sprunck, Stefanie; Dresselhaus, Thomas

2015-05-07

Fertilization of both egg and central cell is a major distinguishing feature of flowering plants. Now, Maruyama et al. report a third cell fusion event between the persistent synergid and the fertilized central cell shortly after double fertilization in Arabidopsis. This causes rapid dilution of pollen tube attractant(s), preventing polytubey. Copyright © 2015 Elsevier Inc. All rights reserved.

The effects of migrant remittances on population–environment dynamics in migrant origin areas: international migration, fertility, and consumption in highland Guatemala

Science.gov (United States)

Lopez-Carr, David

2010-01-01

International migration impacts origin regions in many ways. As examples, remittances from distant migrants may alter consumption patterns within sending communities, while exposure to different cultural norms may alter other behaviors. This paper combines these insights to offer a unique lens on migration’s environmental impact. From an environmental perspective, we ask the following question: is the likely rise in consumption brought about by remittances counterbalanced by a reduction in fertility in migrant households following exposure to lower fertility cultures? Based on ethnographic case studies in two western highland Guatemalan communities, we argue that the near-term rise in consumption due to remittances is not counterbalanced by rapid decline in migrant household fertility. However, over time, the environmental cost of consumption may be mitigated at the community level through diffusion of contraception and family planning norms yielding lower family size. PMID:21258636

Status and trends of amphibian declines and extinctions worldwide.

Science.gov (United States)

Stuart, Simon N; Chanson, Janice S; Cox, Neil A; Young, Bruce E; Rodrigues, Ana S L; Fischman, Debra L; Waller, Robert W

2004-12-03

The first global assessment of amphibians provides new context for the well-publicized phenomenon of amphibian declines. Amphibians are more threatened and are declining more rapidly than either birds or mammals. Although many declines are due to habitat loss and overutilization, other, unidentified processes threaten 48% of rapidly declining species and are driving species most quickly to extinction. Declines are nonrandom in terms of species' ecological preferences, geographic ranges, and taxonomic associations and are most prevalent among Neotropical montane, stream-associated species. The lack of conservation remedies for these poorly understood declines means that hundreds of amphibian species now face extinction.

Soil water and xylem chemistry in declining sugar maple stands in Pennsylvania

Science.gov (United States)

David R. DeWalle; Bryan R. Swistock; William E. Sharpe

1999-01-01

Evidence is accumulating that decline of sugar maple, Acer saccharum Marsh., in northern Pennsylvania may be related to overall site fertility as reflected in the chemistry of soil water and bolewood xylem. In this paper we discuss factors related to varying site fertility, including effects of soil liming, past glacialion, topographic position and...

Decomposing trends in nonmarital fertility among Latinas.

Science.gov (United States)

DeLeone, Felicia Yang; Lichter, Daniel T; Strawderman, Robert L

2009-09-01

For Latinos, high rates of nonmarital fertility reinforce economic inequality and slow the pace of social and economic incorporation into American society. Changes in the nonmarital fertility ratio--nonmarital births as a percentage of all births (NMFR)--among women aged 15-44 over the period 1994-2005 were partitioned into three components: changes in marital and in nonmarital fertility, and in the proportion of women who were married. Annual birth data were drawn from the national Natality Detail File, and population estimates were drawn from the Current Population Surveys. Analyses were conducted for blacks, whites and Latinas, as well as for selected subgroups of Latinas; differences in NMFRs between racial and ethnic groups were also calculated. NMFRs were largely unchanged between 1994 and 2002, and then began to rise; they averaged 43% for Latinas, 69% for blacks and 23% for whites over the study period. In 2005, 48% of births to Latinas were nonmarital. Most of the rise in Latinas' NMFR was linked to a decline in marriage. Among foreign-born Latinas, a six-percentage-point increase in the NMFR was due mostly to a rise in nonmarital fertility and a decline in marital fertility, which offset the beneficial effects of a rising marriage rate. The difference between Latinas' and whites' NMFRs was largely attributed to Latinas' higher nonmarital fertility, whereas the difference between blacks' and whites' NMFRs was driven mostly by lower marriage rates among blacks. Efforts to reduce out-of-wedlock childbearing among Latinas are needed, and programs should promote healthy marriages, especially among foreign-born Latinas.

Urban fertility responses to local government programs: Evidence from the 1923-1932 U.S.

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Jonathan Fox

2015-02-01

Full Text Available Background: During the 1920s and early 1930s, U.S. fertility declined overall but with large regional variations. Changes in foreign born populations explain only part of this. Differences in public health and poverty relief programs may further help explain these declines because of their potential impact on fertility determinants, in particular on breastfeeding and child mortality. Objective: We investigate whether public health investments in child health (conservation of child life programs and poverty relief (outdoor care of poor or charity for children and mothers affected fertility for U.S. cities over 100,000 persons between 1923 and 1932. Methods: We analyze data covering 64 cities between 1923-1932 that include birth information from the U.S. Birth, Stillbirth and Infant Mortality Statistics volumes and city financial information from the Financial Statistics of Cities volumes. Time and city fixed-effects models are used to identify the impact of public investments on fertility. Results: Fixed effects estimates indicating the conservation of child life programs explain about 10 percent of the fertility change between 1923 and 1932. Outdoor care of poor did not seem to be related to fertility. Investments in charity for children and mothers were associated with fertility increases, possibly because poorer areas experienced relative increases in both higher fertility and charitable spending. Conclusions: Public spending on child health was strongly related to decreasing fertility in the U.S. during the 1920s, possibly because of increased breastfeeding and decreased child mortality. This leads to a better understanding of the 1920s fertility decline and highlights how public policy may affect fertility.

The relationship of long term global temperature change and human fertility.

Science.gov (United States)

Fisch, Harry; Andrews, Howard F; Fisch, Karen S; Golden, Robert; Liberson, Gary; Olsson, Carl A

2003-07-01

According to the United Nations, global fertility has declined in the last century as reflected by a decline in birth rates. The earth's surface air temperature has increased considerably and is referred to as global warming. Since changes in temperature are well known to influence fertility we sought to determine if a statistical relationship exists between long-term changes in global air temperatures and birth rates. The most complete and reliable birth rate data in the 20th century was available in 19 industrialized countries. Using bivariate and multiple regression analysis, we compared yearly birth rates from these countries to global air temperatures from 1900 to 1994.A common pattern of change in birth rates was noted for the 19 industrialized countries studied. In general, birth rates declined markedly throughout the century except during the baby boom period of approximately 1940 to 1964. An inverse relationship was found between changes in global temperatures and birth rates in all 19 countries. Controlling for the linear yearly decline in birth rates over time, this relationship remained statistically significant for all the 19 countries in aggregate and in seven countries individually (phuman fertility may have been influenced by change in environmental temperatures.

Does fertility decrease household consumption?: An analysis of poverty dynamics and fertility in Indonesia

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Jungho Kim

2009-06-01

Full Text Available This paper presents an empirical analysis of the relationship between fertility and a direct measure of poverty for Indonesia, a country, which has experienced unprecedented economic growth and sharp fertility declines over recent decades. It focuses on illustrating the sensitivity of the effect of fertility on household consumption with respect to the equivalence scale by applying the propensity score matching method. The analysis suggests that a newborn child decreases household consumption per person by 20 percent within four years. When the estimates of equivalence scales implied by the Indonesian sample are applied, the effect of a child on household consumption is still negative, but the magnitudes are in the range from 20 to 65 percent of that found with the per-capita expenditure as a measure of consumption. Therefore, it is suggested that the analysis based on the conventional measure of poverty is likely to exaggerate the effect of fertility on poverty at least because of the neglect of the proper equivalence scale.

Inverse J-Shaped Relationship between Fertility and Gender Equality: Different Relationships of the Two Variables According to Income Levels

OpenAIRE

2018-01-01

The fertility decline, which started first in developed countries, has been observed among most developing countries since the latter half of the 20th century. On the other hand, among developed countries, the long-lasting decline of fertility seems to have stopped in recent decades, and a modest recovery of fertility has been observed in most countries.A large number of studies focusing on the relationship between fertility and gender equality have been conducted. However, gender equality is...

Some relations among cultural traditions, nuptiality and fertility.

Science.gov (United States)

Coale, A J

1991-01-01

Demographic transition is a period characterized by changes in mortality and fertility that accompany modernization and economic development. Typical features of age at first marriage among populations in different stages of demographic transition are described including the changes in age at marriage, the association between marriage age changes and fertility control, and the role of cultural and traditional behavior in influencing age at marriage and initiation of fertility control. In the Western model, there was a late age of marriage for women between 23 and 28 years old, and a high proportion of women who remain single until 50 years old (10-25%). The Eastern European model was one of moderately early marriage (mean age 19-22) and a small proportion remaining single (2-5%). The third model was Asian and African with early (mean age of 18 years) and universal marriage (1% unmarried). The reduction in number married was associated with reduced fertility. The differences between the Eastern and Western models were in household composition. In premodern societies, any fertility control present was governed by custom and limited biomedical influences such as duration of breast feeding and sexual abstention following a birth. These practices were not considered deliberate fertility control. The mean age of marriage in India was 14 years until 1941 and slowly reached 18.4 years in 1981. Fertility did not begin to decline until after 1960. Examples are given of the close association between marital fertility that is voluntary controlled and mean age at marriage. The influences of culture and traditions on the association between mean age of marriage and voluntary fertility control are shown by examples from the Soviet Union. The eastern part of the Soviet Union experienced a rise in mean age of marriage and an unsustained decline in marital fertility similar to that in China. There were also similarities in nuptiality and fertility between other areas in the Soviet

South Korea's low fertility raises European-style issues.

Science.gov (United States)

Haub, C

1991-10-01

A demographic revolution has taken place in South Korea as evidenced by the marked decline in total fertility rate (TFR) from 6 in 1960 to the 1987 level of 1.6. South Korea holds the record for low fertility among developing countries, with women in South Korea averaging fewer children in their lifetimes than do women in Europe. The 1987 TFR for South Korea was even less than that of Sweden, Norway, and France. Emphasizing high initial rates of contraceptive use, family planning (FP) has been a strong component of South Korea's 5-year plans since 1962. Strong governmental support backed the efforts of a large group of FP workers who provided free contraceptives from private physicians. High discontinuation rates resulted, however, and the abortion rate has soared to equal the number of live births. Albeit a developing nation, South Korea now faces the challenges of below replacement fertility more typical of more developed countries. Current fertility levels indicate population increase to approximately 50 million by 2020, followed by a slow decline. While reducing pressure on limited resources, population decline and demographic aging will also demand allocation of a higher proportion of government funds to medical care, and potentially threaten South Korea's competitiveness in the world labor market. Having effected decreases in population growth and fertility, the government reduced the annual sterilization target in 1986 from 300,000 to 60,000 by 1991, and will increasingly turn to the private sector and national health insurance for service provision to all but the poor. A 2-child family norm may be promoted, FP programs expanded to the unmarried and legislation developed to eliminate the preference for sons. Delivery systems may also be reorganized to encourage continued use of contraceptive methods.

Effect of plant biomass, manure and inorganic fertilizer on maize ...

African Journals Online (AJOL)

Soil fertility degradation remains the major biophysical cause of declining per capita crop production on smallholder farms in sub-Saharan Africa. Appropriate soil fertility regimes, are therefore, critical for ... These treatments maintained maize yields at 4 to 6 t ha-1. Farmers had their own innovations where they combined ...

Rural people's response to soil fertility decline : the Adja case (Benin)

NARCIS (Netherlands)

Brouwers, J.H.A.M.

1993-01-01

This study examines rural people's knowledge in changing conditions such as decreasing soil fertility and increasing population. It explores how farmers, who depend on rainfed agriculture and are confronted with an ever increasing population, react. The study presents the case of an ethnic

Genetics and genomics to improve fertility in high producing dairy cows

NARCIS (Netherlands)

Veerkamp, R.F.; Beerda, B.

2007-01-01

Improving dairy cow fertility by means of genetic selection is likely to become increasingly important, since it is now well established that declining fertility cannot only be arrested by improved management. Profit margins per kg milk produced are decreasing, therefore farmers need to reduce cost

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

Effect of famine on fertility in a rural area of Bangladesh.

Science.gov (United States)

Razzaque, A

1988-07-01

Data on household socioeconomic status collected in the 1974 census and registration data on births, deaths, and migrations for the 1974-77 period from the Demographic Surveillance System of the International Centre for Diarrheal Disease Research, Bangladesh, were used to investigate the effects of the 1974-75 famine on differential fertility in a rural population of Bangladesh. Occupation of household head was used as a measure of socioeconomic status. Overall, fertility declined by 34% over the 1975-76 period and increased by 17% in 1976-77 from the 1974-75 figure. Significantly lower fertility was observed in 1975-76, irrespective of socioeconomic status, but the lower socioeconomic groups were affected more than the higher groups. Post-famine fertility was significantly higher only in the 2 middle occupation categories. The age-specific fertility rates suggest that the famine affected all age groups. The post-famine fertility was higher than that of 1974-75 in all but those aged below 20. At age 40 and over the recovery was slight. Husband-wife separation showed an increase during the famine and particularly among the lower socioeconomic groups. The males of the lower socioeconomic households migrated to other regions to obtain food for the family, thus affecting frequency of coitus. The decline in fertility may be due to several factors: deferred marriage; increase in divorces and husband-wife separations; high fetal wastage; voluntary fertility control through contraception, abstention, or induced abortion; and infecundability. An indirect measure of marriage rate indicated that fewer couples entered into marriage in 1974-75, particularly in the lower socioeconomic groups. Both the higher and lower socioeconomic groups were affected by the famine but the precise mechanisms were not the same. At this stage, it is not feasible to estimate the contribution of each factor to the fertility decline. The lower socioeconomic groups were more affected by husband

The effect of neighbourhood mortality shocks on fertility preferences: a spatial econometric approach.

Science.gov (United States)

Owoo, Nkechi S; Agyei-Mensah, Samuel; Onuoha, Emily

2015-07-01

According to the demographic transition theory, fertility rates fall in response to declines in child mortality rates. Although national statistics indicate that child mortality rates have been declining over time, Ghana's fertility rates appear to have stalled. This paper hypothesises that women's fertility behaviours may be more responsive to child mortality experiences at more localised levels. Using all rounds of the Ghana Demographic and Health Surveys (1988-2008) and employing a variety of spatial and empirical estimation techniques, results indicate that in addition to own-child mortality, neighbourhood child mortality shocks are also a determinant of women's fertility in Ghana. Women in neighbourhoods with large child mortality shocks may desire more children as an "insurance" against future losses, as a result of their increased perceptions of own-child mortality risks.

Fertility in Alberta in a Context of Rapid Economic Growth, 1997-2007

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Frank Trovato

2010-01-01

Full Text Available Historically, birth rates in Alberta have followed closely the trajectory of change experienced by the other Canadian provinces. Its total fertility rate fell during the low point of the 1930s; it increased during the post-War baby boom in the 1950s and sixties, and thereafter fell to sub-replacement levels beginning in the mid 1970s. In recent years, especially since the early 2000s, the birth rate in Alberta has unexpectedly increased, such that by 2007, it had reached 1.90 children per woman---not far from the 2.1 level needed for generational replacement in the long term. During this same period both national and provincial fertility rates fluctuated at levels below those of Alberta (except Saskatchewan and Manitoba, whose rates have been higher. In this study, I examine the historical pattern of fertility change in Alberta, noting similarities and differences with the other provinces. I then look at the association of selected macro level factors (marriage, unemployment, wages, female labour force participation with change in total and parity-specific birth rates between 1997 and 2007, a period of unprecedented economic growth in Alberta. The statistical results show that although marriage is not significantly correlated with change in fertility rates, male and female wages and female labour force participation all show associations consistent with a procyclical interpretation of fertility change --- that is, periods of economic growth are conducive to fertility increase whereas bad economic times lead to reduced fertility.

Fertility in Alberta in a Context of Rapid Economic Growth, 1997-2007

Directory of Open Access Journals (Sweden)

Frank Trovato

2010-12-01

Full Text Available Historically, birth rates in Alberta have followed closely the trajectory of change experienced by the other Canadian provinces. Its total fertility rate fell during the low point of the 1930s; it increased during the post-War baby boom in the 1950s and sixties, and thereafter fell to subreplacement levels beginning in the mid 1970s. In recent years, especially since the early 2000s, the birth rate in Alberta has unexpectedly increased, such that by 2007, it had reached 1.90 children per woman - not far from the 2.1 level needed for generational replacement in the long term. During this same period both national and provincial fertility rates fluctuated at levels below those of Alberta (except Saskatchewan and Manitoba, whose rates have been higher. In this study, I examine the historical pattern of fertility change in Alberta, noting similarities and differences with the other provinces. I then look at the association of selected macro level factors (marriage, unemployment, wages, female labour force participation with change in total and parity-specific birth rates between 1997 and 2007, a period of unprecedented economic growth in Alberta. The statistical results show that although marriage is not significantly correlated with change in fertility rates, male and female wages and female labour force participation all show associations consistent with a procyclical interpretation of fertility change - that is, periods of economic growth are conducive to fertility increase whereas bad economic times are associated with reduced fertility.

Fertility and Family Policies in Central and Eastern Europe after 1990

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Tomas Frejka

2016-06-01

For the first time ever an overview and analysis of CEE family policies is conceptualized in this paper. It demonstrates that fertility trends and family policies are a matter of serious concern throughout the region. The following family policy types have been identified: comprehensive family policy model; pro-natalist policies model; temporary male bread-winner model; and conventional family policies model. The majority of family policies in CEE countries suffer from a variety of shortcomings that impede them from generating enhanced family welfare and from providing conditions for cohort fertility to increase. The likely further decline of cohort fertility, or its stagnation, may entail long-term demographic as well as other societal consequences, such as continuous declines in total population numbers, changes in age structures, as well as implications for health and social security costs.

Soil fertilization leads to a decline in between-samples variability of microbial community δ13C profiles in a grassland fertilization experiment.

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Stavros D Veresoglou

Full Text Available Gas chromatography combustion isotope ratio mass spectrometry (GC-C-IRMS was used to measure the (13C/(12C ratios of PLFAs at natural abundance levels from a temperate grassland nitrogen (N and phosphorus (P factorial fertilization experiment in northern Greece. In each plot two rhizosphere samples were derived centred around individual Agrostis capillaris and Prunella vulgaris plants. It was hypothesized that the isotopic signal of microbes that preferentially feed on recalcitrant litter such as fungi would be modified by fertilization more strongly than that of opportunistic microbes using labile C. Microbial community δ(13C was affected by both P and N fertilization regime and plant species identity. However, we have been unable to detect significant nutrient effects on individual groups of microbes when analyzed separately in contrast to our original hypothesis. Intra-treatment variability, as evaluated from Hartley's F(max tests in the five first PCA components axes as well as the size of the convex hulls in PCA scoreplots and Mahalanobis distances, was considerably higher in the non-fertilized controls. Moreover, a significant relationship was established between the change in PLFA abundances and their respective changes in δ(13C for the aggregate of samples and those simultaneously fertilized with N and P. We conclude that use of compound specific isotope analysis in the absence of labelling represents a valuable and overlooked tool in obtaining an insight of microbial community functioning.

Female relative wages, household specialization and fertility

OpenAIRE

Siegel, Christian

2017-01-01

Falling fertility rates have often been linked to rising female wages. However, over the last 40 years the US total fertility rate has been rather stable while female wages have continued to grow. Over the same period, women's hours spent on housework have declined, but men's have increased. I propose a model in which households are not perfectly specialized, but both men and women contribute to home production. As the gender wage gap narrows, the time allocations of men and women converge, a...

Fertility in Islamic Republic of Iran: Levels, Trends and Differentials during Three Decades (1967-1996

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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.

Reproductive behaviour in the 1980s: Europe revisited. Council of Europe: an account of the work of a committee of experts on fertility trends.

Science.gov (United States)

Deven, F

1985-01-01

This article highlights the findings of a 3-stage analysis conducted in 1982-85 by the Council of Europe Committee of Experts on Fertility Trends: The 1st phase involved a demographic analysis of reproductive behavior in the past decade, the 2nd focused on the background of recent fertility trends, and the 3rd examined possible consequences of these trends. Participating countries included Belgium, France, Federal Republic of Germany, Luxembourg, the Netherlands, Norway, Portugal, Spain, and Switzerland. During the 1970s; most of these countries experienced a continuation of the fertility decline begun in the mid-60s, resulting in the large majority of countries in below-replacement reproduction. In general, the effect of the fertility decline on the birth rate has been partially compensated by the favorable age structure of the reproductive age population. In the 1st half of the 1970s, both nuptiality and reproductive behavior in marriage contributed to the fertility decline; in the 2nd half, marital fertility showed increases. The fertility decline in the 1st half of the 1970s largely reflected the steep decline in fertility among younger age groups, whereas a rise in the fertility in the older age groups was a characteristic of the late 1970s. However, the stabilization or even slight increase in fertility noted in the late 1970s in several European countries reverted to a decline in the early 1980s. In general, small family size appears to be viewed as a good compromise between pyschological and economic costs and benefits. These low fertility trends have had a dramatic effect on household composition and have also facilitated women's personal growth and economic independence. These trends are expected to lead to demographic aging of the population and alleviation of pressures on the labor market. All such changes will require adaptive population policy measures. It is important that such policies do not endanger achievements of modernization such as human

Too old to have children? Lessons from natural fertility populations.

Science.gov (United States)

Eijkemans, Marinus J C; van Poppel, Frans; Habbema, Dik F; Smith, Ken R; Leridon, Henri; te Velde, Egbert R

2014-06-01

fertility. We selected six natural fertility populations comprising 58 051 eligible women. While these populations represent different historical time periods, the distribution of the ages at last birth is remarkably similar. The curve denoting the end of fertility indicates that years meaning that almost 98% were able to have at least one child thereafter. The cumulative curve for the end of fertility slowly increases from 4.5% at age 25 years, 7% at age 30 years, 12% at age 35 years and 20% at age 38 years. Thereafter, it rises rapidly to about 50% at age 41, almost 90% at age 45 years and approaching 100% at age 50 years. It may be argued that these historical fertility data do not apply to the present time; however, the age-dependent decline in fertility is similar to current populations and is consistent with the pattern seen in women treated by donor insemination. Furthermore, for reproductive ageing, we note that it is unlikely that such a conserved biological process with a high degree of heritability would have changed significantly within a century or two. We argue that the age-specific ALB curve can be used to counsel couples who envisage having children in the future. Our findings challenge the unsubstantiated pessimism regarding the possibility of natural conception after age 35 years. No external funding was either sought or obtained for this study. There are no conflicts of interest to be declared.

Male fertility in Greece: Trends and differentials by education level and employment status

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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 dynamics. Objective: This paper intends to study fertility variations over time, relying solely on data referring to father's socio-demographic characteristics; in particular, their age, education level, and employment status. Methods: We use a combination of Labor Force Survey and Demographic Statistics data on population and Vital Statistics on births to estimate male fertility indicators and fertility differentials by education level and employment status, for the period 1992-2011 in Greece. In addition, over-time developments in male TFR are separated into structural (education-specific and employment-specific distributions and behavioral (fertility, per se changes. Results: We find that the male fertility level is declining, the fertility pattern is moving into higher ages, and the reproduction period for men is getting shorter. From 1992 up to 2008, changes in male fertility were mostly driven by behavioral rather than compositional factors. However, the decline of male fertility over the period of economic recession (2008-2011 is largely attributed to the continuous decrease in the proportions of employed men. Conclusions: The study suggests that male fertility merits further exploration. In particular, years of economic downturn and countries where household living standards are mostly associated with male employment, a father's employability is likely to emerge as an increasingly important factor of fertility outcomes.

Fertility in female childhood cancer survivors

DEFF Research Database (Denmark)

De Bruin, Marie L; Van Dulmen-den Broeder, Eline; Van den Berg, Marleen H

2009-01-01

chemotherapy and radiotherapy may have an adverse effect on ovarian function, ovarian reserve and uterine function, clinically leading to sub-fertility, infertility, premature menopause and/or adverse pregnancy outcomes. Here we will first address normal female fertility and methods to detect decreased...... fertility. Hence we will focus on direct effects as well as late fertility-related adverse effects caused by chemotherapy and radiotherapy, and we will conclude with a summary of current options for fertility preservation in female childhood cancer survivors.......Advances in childhood cancer treatment over the past decades have significantly improved survival, resulting in a rapidly enlarging group of childhood cancer survivors. There is much concern, however, about the effects of treatment on reproductive potential. In women there is evidence that both...

Division S-4-soil fertility and plant nutrition

International Nuclear Information System (INIS)

Norman, R.J.; Gilmour, J.T.

1987-01-01

A portion of anhydrous NH 3 fertilizer applied to soil can be rendered nonexchangeable through fixation by clay minerals and soil organic matter. The plant availability of anhydrous NH 3 fixed by these two soil fractions can be important agronomically if such fixation limits plant uptake of the fertilizer N. In this study, three soils with clay and organic C contents ranging from 120 to 310 and 7.8 to 30.1 g kg -1 , respectively, were injected with 15 N-labeled (2 atom % 15 N) liquid anhydrous NH 3 at a rate equivalent to 245 kg N ha -1 . Soluble and exchangeable N were removed by leaching and the soil was cropped to rye grass (Lolium multiflorum Lam.) in pots. Soils were analyzed before and after cropping for clay fixed N and organic matter fixed N. Four cuttings (harvests) were made at 3- to 4-week intervals and roots were collected at the termination of the experiment. Above ground dry matter, total N uptake, and fertilizer-derived fixed N uptake (mg N pot -1 ) increased from the first to the second harvest and declined thereafter. Nitrogen recovered in the roots accounted for <11% of the total N and <7% of the fixed N utilized, and root dry matter accounted for 13 to 14% of the total dry matter produced. The ratio of fertilizer-derived fixed N uptake to total N uptake declined with harvest suggesting that the fixed N became less available to the rye grass with time. Fertilizer-derived fixed N recovered in the rye grass ranged from 19 to 26% of that originally fixed by the soil. The percentages of fertilizer-derived clay fixed N removed from the soils during cropping (35-72%) were much larger than those of the fertilizer-derived organic matter fixed N (<12%) suggesting that a majority of the plant uptake of fixed N originated in the clay fraction. Overall, fertilizer-derived fixed N removal from the soils (21-30%) agreed well with plant uptake data

Structural and diffusion effects in the Dutch fertility transition, 1870-1940

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Hilde Bras

2014-01-01

Full Text Available Background: Ever since the Princeton European Fertility Project, structural and diffusion effects on fertility behavior have been juxtaposed. However, we still hardly know what the relative effects were of shifting socio-economic conditions and shifts in sociability in explaining the historical fertility decline. Objective: To what extent and how did structural and diffusion effects play a role in the adoption of fertility control in the Dutch historical fertility transition? Methods: A national data set was used with more than 3,000 maternity histories of married Dutch women aged 15-50, whose reproductive careers took place between 1870 and 1940. Apart from husbands' occupations, characteristics of the set of couples' marriage witnesses were included to measure their social networks. Cox regression analyses of age at last birth and negative binomial regressions of net family size were conducted. Results: Results indicate that unskilled laborers and farm laborers were laggards in the practice of fertility control during the Dutch fertility transition. Besides SES differentials, differences in couples' social networks were important in explaining fertility behavior. Those who had networks consisting of lateral kin, age peers, and people of urban background stopped childbearing earlier and had smaller families than other couples did. Particularly the presence of lateral kin of the bride and of female witnesses was strongly associated with smaller family size. Conclusions: The evidence lends support for so-called "blended diffusion models" and suggests that the fertility transition must be understood as much from the viewpoint of changed cost-benefit calculations related to structural changes, as from shifting patterns of sociability associated with the decline of patriarchy and the increasing lateralization and age homophily of people's social networks.

Smoke, alcohol and drug addiction and male fertility.

Science.gov (United States)

Sansone, Andrea; Di Dato, Carla; de Angelis, Cristina; Menafra, Davide; Pozza, Carlotta; Pivonello, Rosario; Isidori, Andrea; Gianfrilli, Daniele

2018-01-15

In recent decades, the decline in human fertility has become increasingly more worrying: while therapeutic interventions might help, they are vexing for the couple and often burdened with high failure rates and costs. Prevention is the most successful approach to fertility disorders in males and females alike. We performed a literature review on three of the most common unhealthy habits - tobacco, alcohol and drug addiction - and their reported effects on male fertility. Tobacco smoking is remarkably common in most first-world countries; despite a progressive decline in the US, recent reports suggest a prevalence of more than 30% in subjects of reproductive age - a disturbing perspective, given the well-known ill-effects on reproductive and sexual function as well as general health. Alcohol consumption is often considered socially acceptable, but its negative effects on gonadal function have been consistently reported in the last 30 years. Several studies have reported a variety of negative effects on male fertility following drug abuse - a worrying phenomenon, as illicit drug consumption is on the rise, most notably in younger subjects. While evidence in these regards is still far from solid, mostly as a result of several confounding factors, it is safe to assume that cessation of tobacco smoking, alcohol consumption and recreational drug addiction might represent the best course of action for any couple trying to achieve pregnancy.

Poor knowledge of age-related fertility decline and assisted reproduction among healthcare professionals.

Science.gov (United States)

García, Désirée; Vassena, Rita; Prat, Andrés; Vernaeve, Valérie

2017-01-01

Reproduction is a matter of concern for individuals and society due to the postponement of childbearing, and healthcare professionals are the main source of information and counselling. This study aims to evaluate how knowledgeable healthcare professionals are about fertility and assisted reproduction, and to explore attitudes towards social oocyte freezing. A cross-sectional study was performed with 201 professionals (gynaecologists, physicians and nurses) from four public centres in Spain. Participants completed a survey about fertility, IVF, oocyte donation (OD) and social oocyte freezing, between May 2013 and March 2014. Reported mean age limits for pregnancy were 39.5 ± 4.5 (spontaneously), 43.7 ± 5.2 (IVF) and 49.0 ± 6.5 (OD). Gynaecologists reported a younger limit for spontaneous and IVF pregnancies (P 39, compared with 77.3% of other physicians and 72.9% of nurses. Regarding social oocyte freezing, 41.8% of gynaecologists thought it should be offered to every young woman, versus 62.7% of other physicians and 48.9% of nurses (P = 0.041). In conclusion, gynaecologists are more knowledgeable about fertility and assisted reproduction, while more restrictive towards social oocyte freezing. Knowledge and attitudes could influence the quality of information and counselling given to patients. Copyright © 2016 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

Fertility behaviour of recent immigrants to Israel

Directory of Open Access Journals (Sweden)

2004-03-01

Full Text Available The fertility practices of immigrants are a particularly interesting field of study for demographers, providing an insight into the fertility behaviour of individuals when both the society and the individual undergo a period of rapid change. This paper describes and compares the fertility behaviour of two large groups of immigrants, from the former Soviet Union (FSU and from Ethiopia to Israel in the last 20 years. The changes in fertility behaviour undergone in the same society and at the same time by two very different groups are examined. The findings reveal that the fertility behaviour of immigrants is indeed changing. The fertility of FSU immigrants is increasing and that of the Ethiopian immigrants decreasing, with accompanying changes in the proximate determinants of fertility. Although the fertility of immigrants is becoming more similar to that of the receiving society, the methods employed to achieve the fertility change are not necessarily similar, and, in some cases, diverge from the norms of the receiving society.

The birth rate decline in developing countries.

Science.gov (United States)

Robey, B

1993-01-01

Family planning programs historically have played an important role in providing information and counseling and supplying modern methods. Most programs are effective due to socioeconomic development and strong political support. Potential demand for services will be growing. This means that donor agencies must commit additional funding, and users must begin paying or paying more for contraceptives. Services and method choices need to be expanded, and quality of care needs to be improved. Three primary factors will impact on fertility decline: 1) the rate of social development, 2) the speed with which small family norms spread and contraception is adopted, and 3) the facility of private and public suppliers to meet contraceptive demand. Other factors influence reproductive decisions (women's roles and status, economic hardships or opportunities, religion, ethnicity, culture, and tradition). Contraceptive prevalence has increased from under 10% in the 1960s to 38% of all married, reproductive age women in the developing world, excluding China, which has contraceptive prevalence of 72%. Regional differences are wide. In Latin America, contraceptive use averages nearly 60% and ranges from over 50% in 10 countries and below 38% in Bolivia, Guatemala, and Haiti. Contraceptive prevalence is above average in Indonesia (50%), Sri Lanka (62%), and Thailand (68%) and just below average in Bangladesh (40%), India (45%), Philippines (34%), and Vietnam (53%). Sub-Saharan Africa has the lowest prevalence, except for Zimbabwe (45%), Botswana (35%), and Kenya (27%). 80% of current users rely on modern methods. In most surveyed countries, 20-30% of married women have unmet demand. Fertility decline, unmet demand, and contraceptive use have all been affected by the diffusion of ideas about the use of family planning and the small family norm. Innovators are usually high status, educated women, who spread their views to other social groups or geographic areas. The spread can be rapid

Recent fertility trends in industrialized countries: toward a fluctuating or a stable pattern?

Science.gov (United States)

Day, L H

1995-09-01

The conclusion of this analysis of fertility trends in industrialized countries is that future trends will be evident from accurate data and the inclusion of causal factors such as religion, ethnicity, migration status, marital status, employment status, neighborhood residence, or housing type. Period fertility measures are considered to be unreliable but useful as indicators of potential future changes in fertility. The expectation is that developed countries with low birth rates will have greater fluctuations than trends. Current patterns of fertility in developed countries are thought to have occurred due to substantial control over both the number and the timing of fertility. Patterns in the recent past have reflected further decline, an end to decline and a continued increase, or fluctuation. The most widespread pattern is continued increase following a period of low fertility. This pattern is in evidence in almost every country of northern and western Europe, Canada, the United States, and New Zealand. Countries with continued declines include Japan and eastern and southern European countries, which were the last to experience declines to replacement levels. Countries with fluctuating patterns include Norway, Sweden, and Switzerland. Countries with greater fluctuations include Belgium, Iceland, the former West Germany, the Netherlands, and Poland. The argument is made to not count these patterns as fluctuations due to 1) the similarity in magnitude, timing, and direction; 2) the small changes after the low was reached; and 3) their appearance everywhere at the same time. Stability of rates in the future appears to be a reasonable prospect due to the greater openness about human sexuality and the wider roles for women. Changes have occurred in attitudes about family size in the direction of smaller families, and the range in family size has narrowed considerably. Potential increases may occur due to a new emphasis on family and parenthood, the diminished

Fertility preservation during cancer treatment: clinical guidelines

Science.gov (United States)

Rodriguez-Wallberg, Kenny A; Oktay, Kutluk

2014-01-01

The majority of children, adolescents, and young adults diagnosed with cancer today will become long-term survivors. The threat to fertility that cancer treatments pose to young patients cannot be prevented in many cases, and thus research into methods for fertility preservation is developing, aiming at offering cancer patients the ability to have biologically related children in the future. This paper discusses the current status of fertility preservation methods when infertility risks are related to surgical oncologic treatments, radiation therapy, or chemotherapy. Several scientific groups and societies have developed consensus documents and guidelines for fertility preservation. Decisions about fertility and imminent potentially gonadotoxic therapies must be made rapidly. Timely and complete information on the impact of cancer treatment on fertility and fertility preservation options should be presented to all patients when a cancer treatment is planned. PMID:24623991

Predicting cognitive decline in Alzheimer's disease: an integrated analysis

DEFF Research Database (Denmark)

Lopez, Oscar L; Schwam, Elias; Cummings, Jeffrey

2010-01-01

Numerous patient- and disease-related factors increase the risk of rapid cognitive decline in patients with Alzheimer's disease (AD). The ability of pharmacological treatment to attenuate this risk remains undefined.......Numerous patient- and disease-related factors increase the risk of rapid cognitive decline in patients with Alzheimer's disease (AD). The ability of pharmacological treatment to attenuate this risk remains undefined....

Olive and citrus tree crops and their fertilization in Greece: Field studies with 15N labelled fertilizers

International Nuclear Information System (INIS)

Papanicolaou, E.P.

1982-01-01

Fertilizer use for tree crops in Greece is increasing rapidly, however, fertilizer experiments with olive and citrus tree crops have given results which were often inconclusive. The value of using isotopically labelled fertilizers to directly measure fertilizer uptake is thus obvious. A preliminary experiment determined that relatively low enriched 15 N fertilizers (1.0-1.5% atom excess) could be accurately detected in citrus trees. The concentration of added N was higher in the leaves than in the wood and fruit. In a second study foliarly applied 15 N urea was found to be taken up more efficiently than broadcast urea or ammonium sulphate. In an initial sampling distribution of N among the plant parts was similar to that of the initial study, although a final harvest and analysis must still be conducted. (author)

Time trends in biological fertility in Western Europe

DEFF Research Database (Denmark)

Joffe, Michael; Holmes, Jane; Jensen, Tina Kold

2013-01-01

analyses demonstrated that this rise was visible as a male cohort effect for both TTP and contraceptive failure. On the other hand, the female birth cohort effect showed a slight fall in the first half of the study period for both TTP and contraceptive failure. As a period effect, fertility remained...... of which are calculated to be small. The declining female fertility accords with a falling dizygotic twinning rate during the same period.......We investigated trends in biological fertility in a comprehensive analysis of 5 major European data sets with data on time to pregnancy (TTP) and proportion of contraceptive failures. In particular, we distinguished a period effect from a birth cohort effect (lifelong tendency) in both sexes...

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.

Rapid decline of the volcanically threatened Montserrat oriole.

Science.gov (United States)

Geoff M. Hilton; Phil W. Atkinson; Gerard A.L. Gray; Wayne J. Arendt; David W. Gibbons

2003-01-01

Prior to 1995, the Montserrat oriole (Icterus oberi) was confined to ca. 30 km2 of hill forest on the Lesser Antillean island of Montserrat, but was not listed as globally threatened. Since then, the eruption of the Soufriere Hills volcano has destroyed more than half of the species’ range. Recent intensive monitoring has indicated that the species has also declined...

Building a better hormone therapy?: How understanding the rapid effects of sex steroid hormones could lead to new therapeutics for age-related memory decline

Science.gov (United States)

Frick, Karyn M.

2012-01-01

A wealth of data collected in recent decades has demonstrated that ovarian sex-steroid hormones, particularly 17β-estradiol (E2), are important trophic factors that regulate the function of cognitive regions of the brain such as the hippocampus. The loss of hormone cycling at menopause is associated with cognitive decline and dementia in women, and the onset of memory decline in animal models. However, hormone therapy is not currently recommended to prevent or treat cognitive decline, in part because of its detrimental side effects. In this article, it is proposed that investigations of the rapid effects of E2 on hippocampal function be used to further the design of new drugs that mimic the beneficial effects of E2 on memory without the side effects of current therapies. A conceptual model is presented for elucidating the molecular and biochemical mechanisms through which sex-steroid hormones modulate memory, and a specific hypothesis is proposed to account for the rapid memory-enhancing effects of E2. Empirical support for this hypothesis is discussed as a means of stimulating the consideration of new directions for the development of hormone-based therapies to preserve memory function in menopausal women. PMID:22289043

Gender, Time-Use, and Fertility Recovery in Industrialized Countries

OpenAIRE

García-Manglano, Javier; Nollenberger, Natalia; Sevilla, Almudena

2014-01-01

This paper explores gendered patterns of time use as an explanatory factor behind fertility trends in the developed world. We review the theoretical foundations for this link, and assess the existing evidence suggesting that a more equal division of labor within the home leads to more children, both at the household (micro) and country (macro) levels. After decades of unprecedented fertility decline in the industrialized world, only a handful of countries in the West exhibit replacement ferti...

Investigating the association between HIV/AIDS and recent fertility patterns in Kenya.

Science.gov (United States)

Magadi, Monica Akinyi; Agwanda, Alfred O

2010-07-01

Findings from previous studies linking the HIV/AIDS epidemic and fertility of populations have remained inconclusive. In sub-Saharan Africa, demographic patterns point to the epidemic resulting in fertility reduction. However, evidence from the 2003 Kenya Demographic and Health Survey (KDHS) has revealed interesting patterns, with regions most adversely affected with HIV/AIDS showing the clearest reversal trend in fertility decline. While there is suggestive evidence that fertility behaviour in some parts of sub-Saharan Africa has changed in relation to the HIV/AIDS epidemic, more rigorous empirical analysis is necessary to better understand this relationship. In this paper, we examine individual and contextual community HIV/AIDS factors associated with fertility patterns in Kenya, paying particular attention to possible mechanisms of the association. Multilevel models are applied to the 2003 KDHS, introducing various proximate fertility determinants in successive stages, to explore possible mechanisms through which HIV/AIDS may be associated with fertility. The results corroborate findings from earlier studies of the fertility inhibiting effect of HIV among infected women. HIV-infected women have 40 percent lower odds of having had a recent birth than their uninfected counterparts of similar background characteristics. Further analysis suggests an association between HIV/AIDS and fertility that exists through proximate fertility determinants relating to sexual exposure, breastfeeding duration, and foetal loss. While HIV/AIDS may have contributed to reduced fertility, mainly through reduced sexual exposure, there is evidence that it has contributed to increased fertility, through reduced breastfeeding and increased desire for more children resulting from increased infant/child mortality (i.e. a replacement phenomenon). In communities at advanced stages of the HIV/AIDS epidemic, it is possible that infant/child mortality has reached appreciably high levels where the

Child survival and changing fertility patterns in Pakistan.

Science.gov (United States)

Sathar, Z A

1992-01-01

Pakistan is a country with high fertility and high infant and child mortality, and declines in total mortality and substantial development initiatives. The discussion considers whether fertility patterns in Pakistan can be related to changes in child mortality, and whether current and future changes in fertility influence child survival favorably. Omran's study linked large family size to child survival. Resources, which are divided, become more important deficits in households below the poverty line: a situation common in Pakistan. High fertility is associated with short birth intervals, which are related to higher infant and child mortality. In Pakistan, the spacing and mortality link was found among both poverty and higher socioeconomic households. There is some support for the notion that it is birth weight and general health that are linked to survival rather than competition for resources. Other studies link the maternal age at birth and birth order with child mortality (Alam and Cleland). Trussel argues for limiting births in high risk ages of under 20 years and over 35 years. The exact casual link is not well documented. Institutional and community factors are also considered important in influencing child survival: sanitation, potable water, access to roads, electricity, health and family planning services, and sewage. Young infants are more vulnerable to these factors. Bangladesh and some Indian states have shown that population programs and raising per captia incomes are necessary to fertility decline. In India, female autonomy, access to education, and more equal income distribution were considered more important than economic development to child survival. In Pakistan, Sathar and Kazi have linked at least 2 years of elementary, maternal education with reductions in child mortality. The pervasiveness of female illiteracy hinders the chances of child survival. Sex preferences also impact on female children. The probably impacts of declines in breast

Chinese women's participation in fertility discussions.

Science.gov (United States)

Li, L

1993-01-01

In an attempt to better understand the process through which the family planning (FP) programs and socioeconomic developments in China affect fertility, women's participation in fertility discussions with their husbands are examined as an intermediate factor in a study based on results of a random survey of 6654 ever-married women of reproductive age from 7 cities and 30 counties of Guangdong. First, it must be noted that Chinese couples do have individual choices (albeit quite limited ones) about their fertility; they can choose to follow or ignore government policy or they can choose to remain childless. The present study has 3 major hypotheses: 1) the more a woman is involved in fertility discussions with her husband, the fewer children she will have; 2) urban women with a higher educational status will be more likely to have such discussions; and 3) women who are contacted individually by FP personnel are more likely to be involved in fertility discussions. After a discussion of data collection and variables (number of living children, education of wife and husband, age at marriage, residence, living with parents, contacted by FP personnel, and discussion with husband), the results are presented in terms of zero-order correlation coefficients indicating their relationships. The bivariate analysis supported the hypotheses. Multiple regression analysis showed that age at marriage, education of wives and husbands, FP contacts, and participation in discussions remain significant fertility determinants (but the correlation between fertility and residence becomes trivial). A further regression model indicated that a woman's educational attainment is the most significant positive indication of their participation in fertility discussions. These results imply that as women's status continues to improve in China and the deeply-rooted patriarchal tradition loses hold, increased gender equity and education will influence a fertility decline. FP personnel could also

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.

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.

FERTILIZING INFLUENCE TOWARDS GROWTH AND FRUIT CROPS OF COCOA

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Azri

2015-07-01

Full Text Available TRACT Fertilizers is one activities of maintenance plants that an important role to productivity plants. Without right fertilizing, cacao farms are many setbacks especially in quality of land. Land quality decline because reduction of nutrient in land, damage characteristics of biological or physical and more deplete substantially thickness of land. Nutrient reduction has occur caused by activities of harvest, washing, denitrification, and erosion that occurred in area of cacao plants roots. Damage of biological and physical of land include land aggregate damage, decreased stability of structure, decreased organic matter, and reducing amount of and activities of organisms that live in land. Efforts to increase land fertility can be with gift fertilizer. Study using a Random Group Design with 3 replication, with fertilizer treatment: P1 = Control (farmers; P2 = natural fertilizer 5 kg; P3 = natural fertilizer 5 kg+ 5 g urea + 5 g SP-36, and P4 = natural fertilizer 5 kg+ 5 g SP-36+ 5 g (KC1. Results of study showed that giving of manure and organic matter are significantly different with farmers (control, but best treatment is found on gift manure combined fertilizer anorganic (P3 provides growth and number of best fruit.

Patriarchy and fertility in Albania

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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.

Efficiency of haplotype-based methods to fine-map QTLs and embryonic lethals variants affecting fertility: illustration with a deletion segregating in Nordic Red cattle Corresponding

DEFF Research Database (Denmark)

Kadri, Naveen Kumar; Sahana, Goutam; Guldbrandtsen, Bernt

2014-01-01

Despite its importance, fertility has been declining in many cattle populations. In dairy cattle, this decline is often attributed to the negative correlation between fertility and productions traits. Recent studies showed that embryonic lethal variants might also account for a non-negligible fra...

Ammonia Emissions from agricultural fertilizer in China: From 1978 to 2008

Science.gov (United States)

Xu, P.

2015-12-01

The quantification of ammonia (NH3) emissions is essential to the more accurate quantification of atmospheric nitrogen deposition, improved air quality and the assessment of ammonia-related agricultural policy and climate mitigation strategies. Chinese agricultural fertilizer (CAF), which is widely used in China, is the nation's largest source of NH3 emissions. The quantity, geographic distribution and historical trends of these emissions remain largely uncertain. In this paper, a new CAF NH3 (CAF_NH3) emissions inventory has been compiled that exhibits the following improvements: (1) a 1 ´1 km gridded map on the county level was developed for 2008; (2) a combined bottom-up and top-down method was used for the local correction of emission factors (EFs) and parameters; (3) time trends were derived for 1978-2008 in which the spatial and temporal patterns and the uncertainties associated with the inventory were quantified; and (4) a sensitivity test was performed in which a province-level disaggregated map was compared with CAF_NH3 emissions for 2008. The total CAF_NH3 emissions for 2008 were 8.4 TgNH3·yr-1 (a 6.6-9.8 Tg interquartile range). From 1978 to 2008, annual NH3 emissions fluctuated with three peaks (1987, 1996 and 2005), and total emissions increased from 3.2 to 8.4 Tg at an annual rate of 3.0%. During the study period, the contribution of livestock manure spreading increased from 37.0% to 45.5% because of changing fertilization practices and the rapid increase in egg, milk and meat consumption. The average contribution of synthetic fertilizer, which has a positive effect on crop yields, was approximately 38.3% (minimum: 33.4%; maximum: 42.7%). With rapid urbanization causing a decline in the rural population, the contribution of the rural excrement sector varied widely between 20.3% and 8.5%. The average contributions of cake fertilizer and straw returning were approximately 3.8% and 4.5%, respectively, thus small and stable. Collectively, the CAF NH3

Understanding cropping systems in the semi-arid environments of Zimbabwe: options for soil fertility management

NARCIS (Netherlands)

Ncube, B.

2007-01-01

African smallholder farmers face perennial food shortages due to low crop yields. The major cause of poor crop yields is soil fertility decline. The diversity of sites and soils between African farming systems isgreat,therefore strategies to solve soil fertility problems

Losing a jewel—Rapid declines in Myanmar’s intact forests from 2002-2014

Science.gov (United States)

Horning, Ned; Khaing, Thiri; Thein, Zaw Min; Aung, Kyaw Moe; Aung, Kyaw Htet; Phyo, Paing; Tun, Ye Lin; Oo, Aung Htat; Neil, Anthony; Thu, Win Myo; Songer, Melissa; Huang, Qiongyu; Connette, Grant; Leimgruber, Peter

2017-01-01

New and rapid political and economic changes in Myanmar are increasing the pressures on the country’s forests. Yet, little is known about the past and current condition of these forests and how fast they are declining. We mapped forest cover in Myanmar through a consortium of international organizations and environmental non-governmental groups, using freely-available public domain data and open source software tools. We used Landsat satellite imagery to assess the condition and spatial distribution of Myanmar’s intact and degraded forests with special focus on changes in intact forest between 2002 and 2014. We found that forests cover 42,365,729 ha or 63% of Myanmar, making it one of the most forested countries in the region. However, severe logging, expanding plantations, and degradation pose increasing threats. Only 38% of the country’s forests can be considered intact with canopy cover >80%. Between 2002 and 2014, intact forests declined at a rate of 0.94% annually, totaling more than 2 million ha forest loss. Losses can be extremely high locally and we identified 9 townships as forest conversion hotspots. We also delineated 13 large (>100,000 ha) and contiguous intact forest landscapes, which are dispersed across Myanmar. The Northern Forest Complex supports four of these landscapes, totaling over 6.1 million ha of intact forest, followed by the Southern Forest Complex with three landscapes, comprising 1.5 million ha. These remaining contiguous forest landscape should have high priority for protection. Our project demonstrates how open source data and software can be used to develop and share critical information on forests when such data are not readily available elsewhere. We provide all data, code, and outputs freely via the internet at (for scripts: https://bitbucket.org/rsbiodiv/; for the data: http://geonode.themimu.info/layers/geonode%3Amyan_lvl2_smoothed_dec2015_resamp) PMID:28520726

INFLUENCE OF LEGUME RESIDUE AND NITROGEN FERTILIZER ...

African Journals Online (AJOL)

USER

to search for more arable land with reduction in fallow period and decline in fertility ... The stalks are used as feed, fuel, thatch making and in roofing houses. ... soil nitrogen content can be a practicable alternative to reduce the use of chemical .... significance of legume in nitrogen fixation and its inclusion to cropping system.

Genocide, Nuptiality, and Fertility in Rwanda and Bosnia-Herzegovina

OpenAIRE

Staveteig, Sarah Elizabeth

2011-01-01

How does exposure to genocide affect nuptiality and fertility among the surviving population? Genocides in Rwanda and in Bosnia-Herzegovina in the early 1990s caused high levels of population displacement, trauma, and death, along with a dramatic decline in the standard of living. In Rwanda, genocide also reduced the sex ratio of the marriage-aged population, while in Bosnia, despite the high proportion of male casualties, the overall sex ratio of the marriage-age population did not decline s...

Fertilization of sea urchin eggs and sperm motility are negatively impacted under low hypergravitational forces significant to space flight

Science.gov (United States)

Tash, J. S.; Kim, S.; Schuber, M.; Seibt, D.; Kinsey, W. H.

2001-01-01

Sperm and other flagellates swim faster in microgravity (microG) than in 1 G, raising the question of whether fertilization is altered under conditions of space travel. Such alterations have implications for reproduction of plant and animal food and for long-term space habitation by man. We previously demonstrated that microG accelerates protein phosphorylation during initiation of sperm motility but delays the sperm response to the egg chemotactic factor, speract. Thus sperm are sensitive to changes in gravitational force. New experiments using the NiZeMi centrifugal microscope examined whether low hypergravity (hyperG) causes effects opposite to microG on sperm motility, signal transduction, and fertilization. Sperm % motility and straight-line velocity were significantly inhibited by as little as 1.3 G. The phosphorylation states of FP130, an axonemal phosphoprotein, and FP160, a cAMP-dependent salt-extractable flagellar protein, both coupled to motility activation, showed a more rapid decline in hyperG. Most critically, hyperG caused an approximately 50% reduction in both the rate of sperm-egg binding and fertilization. The similar extent of inhibition of both fertilization parameters in hyperG suggests that the primary effect is on sperm rather than eggs. These results not only support our earlier microG data demonstrating that sperm are sensitive to small changes in gravitational forces but more importantly now show that this sensitivity affects the ability of sperm to fertilize eggs. Thus, more detailed studies on the impact of space flight on development should include studies of sperm function and fertilization.

Advanced reproductive age and fertility.

Science.gov (United States)

Liu, Kimberly; Case, Allison

2011-11-01

To improve awareness of the natural age-related decline in female and male fertility with respect to natural fertility and assisted reproductive technologies (ART) and provide recommendations for their management, and to review investigations in the assessment of ovarian aging. This guideline reviews options for the assessment of ovarian reserve and fertility treatments using ART with women of advanced reproductive age presenting with infertility. The outcomes measured are the predictive value of ovarian reserve testing and pregnancy rates with natural and assisted fertility. Published literature was retrieved through searches of PubMed or Medline, CINAHL, and The Cochrane Library in June 2010, using appropriate key words (ovarian aging, ovarian reserve, advanced maternal age, advanced paternal age, ART). Results were restricted to systematic reviews, randomized controlled trials/controlled clinical trials, and observational studies. There were no date or language restrictions. Searches were updated on a regular basis and incorporated into the guideline to December 2010. The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care. Recommendations for practice were ranked according to the method described in that report (Table). Primary and specialist health care providers and women will be better informed about ovarian aging and the age-related decline in natural fertility and about options for assisted reproductive technology. 1. Women in their 20s and 30s should be counselled about the age-related risk of infertility when other reproductive health issues, such as sexual health or contraception, are addressed as part of their primary well-woman care. Reproductive-age women should be aware that natural fertility and assisted reproductive technology success (except with egg donation) is significantly lower for women in their late 30s and 40s. (II-2A) 2. Because of the decline in fertility and the

Rising up: Fertility trends in Egypt before and after the revolution.

Science.gov (United States)

Radovich, Emma; El-Shitany, Atef; Sholkamy, Hania; Benova, Lenka

2018-01-01

In 2014, Egypt's Demographic and Health Survey (EDHS) documented an increase in the total fertility rate (TFR) to 3.5, up from a low of 3.0 recorded by the 2008 EDHS. The increase has been anecdotally attributed to the social upheaval following Egypt's January 2011 revolution, but little is known about when fertility first began to increase and among which sub-groups of women. Using birth histories from seven rounds of EDHS (1992-2014), this study reconstructed fertility rates for single years from 1990-2013 and examined patterns of childbearing in five-year birth cohorts of women. We found that the decline in fertility reversed in 2007, earlier than postulated, plateaued and then increased again in 2013. The increase in TFR coincided with a convergence of fertility rates across education levels, and there is evidence of a shift toward childbearing at younger ages among more educated women, which may be inflating period measures of fertility.

Rising up: Fertility trends in Egypt before and after the revolution.

Directory of Open Access Journals (Sweden)

Emma Radovich

Full Text Available In 2014, Egypt's Demographic and Health Survey (EDHS documented an increase in the total fertility rate (TFR to 3.5, up from a low of 3.0 recorded by the 2008 EDHS. The increase has been anecdotally attributed to the social upheaval following Egypt's January 2011 revolution, but little is known about when fertility first began to increase and among which sub-groups of women. Using birth histories from seven rounds of EDHS (1992-2014, this study reconstructed fertility rates for single years from 1990-2013 and examined patterns of childbearing in five-year birth cohorts of women. We found that the decline in fertility reversed in 2007, earlier than postulated, plateaued and then increased again in 2013. The increase in TFR coincided with a convergence of fertility rates across education levels, and there is evidence of a shift toward childbearing at younger ages among more educated women, which may be inflating period measures of fertility.

Fertility transition: forecast for demography.

Science.gov (United States)

Caputo, M; Nicotra, M; Gloria-Bottini, E

2008-08-01

By the end of the 20th century most industrialized nations had undergone the so-called fertility transition, characterized by a reduction in fertility to below replacement level and a delay in age at initiation of child-bearing. An emerging concern is the severe economic and social consequences of this demographic decline. We present an overview of fertility changes in Italy in the second half of the 20th century and a mathematical model that may provide projections for the future of the demographic situation. Starting in 1950 the increment of the number of children born in Italy is initially positive; however, beginning in 1965 the trend suddenly becomes negative, and this negative trend further increased in 1975. A slight improvement is observed in 1980, followed by a stable situation beginning in 1987. Relevant socioeconomic and cultural events in Italy coincide with these variations in the fertility trend. Malnutrition, which had been endemic for centuries in some areas of central and southern Italy, disappeared rather abruptly in early 1960. The improvement in the economic situation was also associated with a decrease in illiteracy and with many sociocultural changes, with the emergence of new demands that decreased propensity for childbearing. The additional deceleration observed in 1975 corresponds to the diffusion of contraceptive procedures. The progression of sociocultural changes has led to a progressive liberation of women from the biological burden of childbearing. Two phenomena seem relevant in this context: women's emerging interest in entering the workforce and the possibility to disconnect sex from childbearing. The social function of feminism has overwhelmed the primary function of survival and diffusion of the species, giving rise to relevant and worrying demographic effects. However, the modern woman has an unconscious memory of her primary biological role, depending on both her genetic structure and cultural heritage, that should bring about a

Rapid production of organic fertilizer by dynamic high-temperature aerobic fermentation (DHAF) of food waste.

Science.gov (United States)

Jiang, Yang; Ju, Meiting; Li, Weizun; Ren, Qingbin; Liu, Le; Chen, Yu; Yang, Qian; Hou, Qidong; Liu, Yiliang

2015-12-01

Keep composting matrix in continuous collision and friction under a relatively high-temperature can significantly accelerate the progress of composting. A bioreactor was designed according to the novel process. Using this technology, organic fertilizer could be produced within 96h. The electric conductivity (EC) and pH value reached to a stable value of 2.35mS/cm and 7.7 after 96h of fermentation. The total carbon/total nitrogen (TC/TN) and dissolved carbon/dissolved nitrogen (DC/DN) ratio was decrease from 27.3 and 36.2 to 17.4 and 7.6 respectively. In contrast, it needed 24days to achieve the similar result in traditional static composting (TSC). Compost particles with different size were analyzed to explore the rapid degradation mechanism of food waste. The evidence of anaerobic fermentation was firstly discovered in aerobic composting. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

Solophos fertilizer improved rice plant growth in aerobic soil

OpenAIRE

NIE, Lixiao; PENG, Shaobing; BOUMAN, Bas A.M.; HUANG, Jianliang; CUI, Kehui; VISPERAS, Romeo M.; PARK, Hong-Kyu

2007-01-01

Yield decline of continuous monocropping of aerobic rice is the major constraint to the wide adoption of aerobic rice technology. This study was conducted to determine if solophos fertilizer could be used to reverse the yield decline of this cropping system using pot and micro-plot experiments. The soil for the pot experiment was collected from a field where aerobic rice has been grown continuously for 11 seasons at the IRRI farm. Four rates (4, 6, 8, and 10gpot^) of solophos application were...

Excess Fertility and Family Planning in Rwanda : Understanding the shift to a high contraceptive prevalence country

NARCIS (Netherlands)

Muhoza Ndaruhuye, Dieudonne

2014-01-01

Rwanda has experienced an impressive increase in contraceptive use and fertility decline during the last decade. Between 2005 and 2010, the contraceptive prevalence rate (CPR) has risen from 17 % to 52%, reducing unmet need and the total fertility substantially (from 6.1 to 4.6 children per women).

Developing a Coffee Yield Prediction and Integrated Soil Fertility Management Recommendation Model for Northern Tanzania

NARCIS (Netherlands)

Maro, G.P.; Mrema, J.P.; Msanya, B.M.; Janssen, B.H.; Teri, J.M.

2014-01-01

The aim of this study was to develop a simple and quantitative system for coffee yield estimation and nutrient input advice, so as to address the problem of declining annual coffee production in Tanzania (particularly in its Northern coffee zone), which is related to declining soil fertility. The

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...... starts to decline around 25-30 years. Men had significantly lower fertility awareness. Women who underestimated the impact of age on female fertility were significantly more likely to have a desire or attempted their first child at a higher age. CONCLUSION: Even though the majority were aware of the age......-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...

Fertility and social interaction at the workplace: Does childbearing spread among colleagues?

Science.gov (United States)

Pink, Sebastian; Leopold, Thomas; Engelhardt, Henriette

2014-09-01

This research investigates whether colleagues' fertility influences women's transitions to parenthood. We draw on Linked-Employer-Employee data (1993-2007) from the German Institute for Employment Research comprising 33,119 female co-workers in 6579 firms. Results from discrete-time hazard models reveal social interaction effects on fertility among women employed in the same firm. In the year after a colleague gave birth, transition rates to first pregnancy double. This effect declines over time and vanishes after two years. Further analyses suggest that the influence of colleagues' fertility is mediated by social learning. Copyright © 2013 Elsevier Ltd. All rights reserved.

Long-term agricultural fertilization alters arbuscular mycorrhizal fungal community composition and barley (Hordeum vulgare) mycorrhizal carbon and phosphorus exchange.

Science.gov (United States)

Williams, Alwyn; Manoharan, Lokeshwaran; Rosenstock, Nicholas P; Olsson, Pål Axel; Hedlund, Katarina

2017-01-01

Agricultural fertilization significantly affects arbuscular mycorrhizal fungal (AMF) community composition. However, the functional implications of community shifts are unknown, limiting understanding of the role of AMF in agriculture. We assessed AMF community composition at four sites managed under the same nitrogen (N) and phosphorus (P) fertilizer regimes for 55 yr. We also established a glasshouse experiment with the same soils to investigate AMF-barley (Hordeum vulgare) nutrient exchange, using carbon ( 13 C) and 33 P isotopic labelling. N fertilization affected AMF community composition, reducing diversity; P had no effect. In the glasshouse, AMF contribution to plant P declined with P fertilization, but was unaffected by N. Barley C allocation to AMF also declined with P fertilization. As N fertilization increased, C allocation to AMF per unit of P exchanged increased. This occurred with and without P fertilization, and was concomitant with reduced barley biomass. AMF community composition showed no relationship with glasshouse experiment results. The results indicate that plants can reduce C allocation to AMF in response to P fertilization. Under N fertilization, plants allocate an increasing amount of C to AMF and receive relatively less P. This suggests an alteration in the terms of P-C exchange under N fertilization regardless of soil P status. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

[Association between the decline in global fertility rate and the incorporation of women to the workforce].

Science.gov (United States)

Stefanelli, María de Los Ángeles; Valenzuela, María Teresa; Cárcamo, Marcela; Urquidi, Cinthya; Cavada, Gabriel; San Martín P, Pamela

2016-05-01

The global fertility rate (GFR) is defined as the mean number of children that a woman could have in a hypothetical cohort, not exposed to death during the fertile period. GFR has fallen from 3.4 to 1.9 children per women in the period 1970-2010. To explore the relationship between the fall in GFR and the incorporation of women to work in the period 1960-2011. Data from the National Statistics Institute was used. GRF was calculated using specific fertility rates for each year considering women aged 15 to 49 years. Work rates were obtained from yearly vital statistics reports. Between 1960 and 2011, GRF decreased from 5.5 to 1.9 in Chile. The first inflection occurred in 1970. In the same period, female workforce increased from 22.4 to 40.2%. To motivate the participation of female work-force without decrease the GRF allowing population replacement, it is suggested the need to create new public policies with benefits and support from the state.

Localization of determinants of fertility through measurement adaptations in developing-country settings: The case of Iran: Comment on "Analysis of economic determinants of fertility in Iran: a multilevel approach".

Science.gov (United States)

Erfani, Amir

2014-12-01

Studies investigating fertility decline in developing countries often adopt measures of determinants of fertility behavior developed based on observations from developed countries, without adapting them to the realities of the study setting. As a result, their findings are usually invalid, anomalous or statistically non-significant. This commentary draws on the research article by Moeeni and colleagues, as an exemplary work which has not adapted measures of two key economic determinants of fertility behavior, namely gender inequality and opportunity costs of childbearing, to the realities of Iran's economy. Measurement adaptations that can improve the study are discussed.

Invasive alien predator causes rapid declines of native European ladybirds

DEFF Research Database (Denmark)

Roy, Helen E.; Adriaens, Tim; Isaac, Nick J.B.

2012-01-01

Aim Invasive alien species (IAS) are recognized as major drivers of biodiversity loss, but few causal relationships between IAS and species declines have been documented. In this study, we compare the distribution (Belgium and Britain) and abundance (Belgium, Britain and Switzerland) of formerly...

Tunisia: high fertility stalls development.

Science.gov (United States)

Barberis, M

1985-01-01

Despite government policy enacted in 1964 to reduce fertility in order to hasten socioeconomic progress, population pressures continue to impair development in Tunisia. The birth rate fell 20% over the last 2 decades, but this accomplishment has been outweighed by a 50% decline in mortality rates. As a result, the rate of natural population increase has remained relatively constant at 2.5%/year. The initial decline in fertility that followed introduction of the national family planning program appears to have reached a plateau, explained in part by the resurgence of conservatism and religious fundamentalism and the consequent emphasis on women's childbearing roles. Unemployment in rural areas has led to widespread migration and unemployment is as high as 20% in the nonagricultural sector. Many young Tunisians lack adequate educational preparation to enter the labor force; in 1982, 27% of new job entrants could not read or write. The government's plan to decentralize development to stabilize population and achieve equilibrium between regions has been thwarted by the pace of population growth and limited resources. The rural regions where population is increasing the fastest are also the most difficult to reach with family planning programs. On the other hand, there have been some successes in this area when services have been adapted to the lifestyle and traditions of those in these isolated rural villages.

Comparison of fertility ratios, attitudes and beliefs of Polish and Czech women

Directory of Open Access Journals (Sweden)

Andrzej Brodziak

2013-06-01

Full Text Available Aim of the study: The aim of this study was to estimate some basic data related to the fertility in the chosen groups of Polish and Czech women. We have tried to acquire and analyze the attitudes and beliefs of these women in motherhood and the desire to have children. These data enable to verify the interdisciplinary hypothesis explaining the decline of birth rate and low fertility in European countries. Materials and methods: The authors performed the survey by means of a questionnaire formulated after a comprehensive discussion of possible reasons of birth rate decline. They have tried through the questions of the survey to verify the hypothesis that the decline is the result of the cumulative mental changes occurring in contemporary societies. The questionnaire completed 90 Polish women students pursuing complementary studies of nursing in Higher School of Applied Sciences in Nysa, during the academic year 2012/2013. The questionnaire also completed 53 Czech women students pursuing part-time studies and training at the Tomas Bata University in Zlin (the Czech Republic. Results: The above surveyed 90 Polish women gave birth to 132 children, so fertility rates is 1.46. The average age at the birth of the first child was 24.7 years, of the second child 27.5 and of the third child 31.7 years. The surveyed 53 Czech women gave birth to 86 children, so fertility rates is 1.62. The average age at birth of the first child was 24.7 years, of the second child 27.2 and of the third child 27,5 years. The authors present also convictions, beliefs and attitudes of the women under study. Conclusions: The multifaceted and interdisciplinary hypothesis (theoretical model formulated at the outset of our work, can be useful for attempts to estimate the pro-family attitudes in different populations of women. The results in the light of compliance with the proposed theoretical model allow for the formulation of proposals for action, which would counteract the

Veterinary dairy herd fertility service provision in seasonal and non-seasonal dairy industries - a comparison

Directory of Open Access Journals (Sweden)

Mee JF

2010-04-01

Full Text Available Abstract The decline in dairy herd fertility internationally has highlighted the limited impact of traditional veterinary approaches to bovine fertility management. Three questionnaire surveys were conducted at buiatrics conferences attended by veterinary practitioners on veterinary dairy herd fertility services (HFS in countries with a seasonal (Ireland, 47 respondents and non-seasonal breeding model (The Netherlands, 44 respondents and Portugal, 31 respondents. Of the 122 respondents, 73 (60% provided a HFS and 49 (40% did not. The majority (76% of all practitioners who responded stated that bovine fertility had declined in their practice clients' herds with inadequate cow management, inadequate nutrition and increased milk yield as the most important putative causes. The type of clients who adopted a herd fertility service were deemed more educated than average (70% of respondents, and/or had fertility problems (58% and/or large herds (53%. The main components of this service were routine postpartum examinations (95% of respondents, fertility records analysis (75% and ultrasound pregnancy examinations (69%. The number of planned visits per annum varied between an average of four in Ireland, where breeding is seasonal, and 23 in Portugal, where breeding is year-round. The benefits to both the practitioner and their clients from running a HFS were cited as better fertility, financial rewards and job satisfaction. For practitioners who did not run a HFS the main reasons given were no client demand (55% and lack of fertility records (33%. Better economic evidence to convince clients of the cost-benefit of such a service was seen as a major constraint to adoption of this service by 67% of practitioners.

Using organic fertilizers in forest and native plant nurseries

Science.gov (United States)

Thomas D. Landis; R. Kasten Dumroese

2012-01-01

Since World War II, synthetic fertilizers have been used almost exclusively to grow forest and native plant nursery crops because they are quickly soluble and readily taken up by crops, producing the rapid growth rates that are necessary in nursery culture. In recent years, however, a wide variety of new organic fertilizers have become available. We divided these...

Does Child Labor Decline with Improving Economic Status?

Science.gov (United States)

Edmonds, Eric V.

2005-01-01

The rapid economic growth of Vietnam provides an interesting insight into the sharp decline in child labor. A study of the rising economic status of the population across Vietnam shows that children returned to school or stopped working as their family incomes grew. The decline in child labor is steep in poor households as they emerged from…

Localization of Determinants of Fertility through Measurement Adaptations in Developing-Country Settings: The Case of Iran Comment on “Analysis of Economic Determinants of Fertility in Iran: A Multilevel Approach”

Directory of Open Access Journals (Sweden)

Amir Erfani

2014-12-01

Full Text Available Studies investigating fertility decline in developing countries often adopt measures of determinants of fertility behavior developed based on observations from developed countries, without adapting them to the realities of the study setting. As a result, their findings are usually invalid, anomalous or statistically non-significant. This commentary draws on the research article by Moeeni and colleagues, as an exemplary work which has not adapted measures of two key economic determinants of fertility behavior, namely gender inequality and opportunity costs of childbearing, to the realities of Iran’s economy. Measurement adaptations that can improve the study are discussed.

A Century of Synthetic Fertilizer: 1909-2009

OpenAIRE

Paull, John

2009-01-01

This year marks a centenary of the synthetic fertilizer industry. German chemists, Fritz Haber and Carl Bosch, in 1909 demonstrated their industrial process for the manufacture of ammonia. The achievement won them accolades including Nobel Prizes. The output of their Haber-Bosch process can be used for either peace or war, agriculture or munitions, and the rapid adoption by Germany of this industrial process is credited with prolonging WW1. Most of the synthetic nitrogenous fertilizer of the...

The decline of infant and child mortality among Spanish Gitanos or Calé (1871−2005: A microdemographic study in Andalusia

Directory of Open Access Journals (Sweden)

Juan F. Gamella

2017-03-01

Full Text Available Background: Most Romani groups in Europe have experienced a decline in childhood mortality during recent decades. These crucial transformations are rarely addressed in research or public policy. Objective: This paper analyzes the timing and structure of the decline of childhood mortality among the Gitano people of Spain. Methods: The paper is based on the family and genealogy reconstitution of the Gitano population of 22 contiguous localities in Southern Spain. Registry data from over 19,100 people and 3,501 reconstituted families was included in a dense genealogical grid ranging over 150 years. From this database we produced annual time series of infant and child mortality and of the registered causes of death from 1871 to 2005. Results: The analyzed data shows a rapid decline in infant and child mortality from about 1949 to 1970. The onset of the definitive decline occurred in the late 1940s and early 1950s. Child mortality was higher in the pre-transitional period and started to decline earlier, although it took longer to converge with majority rates. The mortality transition in the Gitano minority paralleled that of the dominant majority, but with important delays and higher mortality rates. The causes of death show the deprivation suffered by Gitano people. Conclusions: The childhood mortality decline facilitated the most important changes experienced recently by the Gitano minority, including its fertility transition and the transformation of Gitanos' gender and family systems. Contribution: This is one of the first historical reconstructions of the mortality transition of a Romani population.

Fertility trends in Serbia during the 1990s

Directory of Open Access Journals (Sweden)

Rašević Mirjana M.

2004-01-01

Full Text Available The 1990s represent an exceptionally complex period for the population of Serbia. In addition to the impact of long-term factors, various tumultuous events affected its demographic development, such as breaking apart of former Yugoslavia, armed conflicts in the neighboring countries, sanctions imposed by the international community, social changes (transition transformation or regression, deep economic crisis, collapse of social stratification political problems, institutional crisis, and NATO military intervention. Maladjustment to the changed system of values and norms, lower level of personal attainment, feeling of insecurity, and living under permanent stress are the main features of life at an individual psychological level. Deprivation or living at the subsistence level are the main elements of the economic cost sustained by the majority of the population. How have these changes affected an individual's decision to have children? The analysis of futility indicators points to an obvious decline in the number of births across low fertility regions of Serbia. Also, the analysis has raised the question why the decline in population fertility in the low fertility regions was not even higher, bearing in mind the experiences undergone by the countries with economy in transition as well as the depth of the crisis in society. In that sense several factors come to mind. The most important are the universality of marriage socio-psychological investigations confirmed domination of the traditional character or mentality in Serbia during the 1990s, and the government’s approach to the issue of fertility improved during this time. Besides demographic needs were carefully taken into account in all amendments to the old and formulation of the new measures in the area of social policy. Mention should be made of measures ensuring employment rights of women and their entitlement to maternity leave, maternity pay, and provision of institutionalized care for

Prevalence of Child Marriage and its Impact on the Fertility and Fertility Control Behaviors of Young Women in India

Science.gov (United States)

Raj, Anita; Saggurti, Niranjan; Balaiah, Donta; Silverman, Jay G.

2009-01-01

Objectives Child marriage in India is considered a major barrier to the nation's social and economic development, as well as a major women's health concern. The current study assesses prevalence of child marriage (i.e., marriage prior to the national legal age of 18 years) among young adult women in India, and associations between child marriage and women's fertility and fertility control behaviors. Study Design Cross-sectional analyses of a nationally representative household sample of Indian women ages 16-49 years (N=124,385) collected in 2005-2006 via the National Family Health Survey-3. Participants Analyses were restricted to women age 20-24 years (n=22,807) and the subsample of ever married women aged 20-24 years (n=14,628). Data Analysis Prevalence estimates of child marriage were produced for all women 20-24 years. Using the ever married subsample, simple regression models, models adjusted for demographics, and models adjusted for demographics and duration of marriage were constructed to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between child marriage and both fertility and fertility control outcomes. Fertility and Fertility Control Outcomes No contraception prior to childbirth, childbirth within first year of marriage, high fertility (3 or more births), history of recent rapid repeat childbirth, unwanted pregnancy, and female sterilization. Results Child marriage was reported by 44.5% of Indian women ages 20-24 years; 22.6% reported marriage prior to age 16 years, and 2.6% were married prior to age 13 years. Child marriage was significantly associated with women's increased risk for no contraceptive use prior to first childbirth (AOR=1.37, 95% CI=1.22, 1.54), high fertility (AOR=7.40, 95% CI=6.45, 8.50), history of rapid repeat childbirth (AOR=3.00, 95% CI=2.74, 3.29), multiple unwanted pregnancies (AOR=2.36, 95% CI=1.90, 2.94), pregnancy termination (AOR=1.22; 95% CI=1.06, 1.41) and female sterilization (AOR=5

Use of isotopically labeled fertilizer to trace nitrogen fertilizer contributions to surface, soil, and ground water

Science.gov (United States)

Wilkison, D.H.; Blevins, D.W.; Silva, S.R.

2000-01-01

The fate and transport of a single N fertilizer application through plants, soil, runoff, and the unsaturated and saturated zones was determined for four years at a field site under continuous corn (Zea mays L.) management. Claypan soils, which underlie the site, were hypothesized to restrict the movement of agrichemicals from the soil surface to ground water. However, N fertilizer moved rapidly through preferential flow paths in the soil and into the underlying glacial till aquifer. Most N transport occurred during the fall and winter when crops were not available to use excess N. Forty months after application, 33 percent of the fertilizer had been removed by grain harvests, 30 percent had been transpired to the atmosphere, and 33 percent had migrated to ground water. Although runoff volumes were 50 percent greater than infiltration, less than 2 percent of the fertilizer was lost to runoff. Small measured denitrification rates and large measured dissolved oxygen concentrations in ground water favor the long-term stability of NO3-1 in ground water. Successive fertilizer applications, in areas that lack the ability to moderate N concentrations through consumptive N reactions, risk the potential of N-saturated ecosystems.

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.

Nitrogen fertilization and yield formation of potato during a short growing period

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L. MUSTONEN

2008-12-01

Full Text Available The effects various rates of nitrogen application on accumulation of dry matter and nitrogen in potato (Solanum tuberosum L. were studied during a short growing period of 140–180 days, at MTT Agrifood Research Finland in 2000–2001. The treatments were 0, 60 and 120 kg N ha-1 and the potato cultivars tested were Van Gogh and Nicola. Four successive harvests were made during the course of the experiment to monitor changes in the accumulation of dry matter and nitrogen over the season. Applications of nitrogen substantially increased haulm dry matter accumulation and to an even greater extent their nitrogen contents. The highest dry matter values were generally registered at 120 kg N ha-1. Dry matter and nitrogen content of haulms started to decline during the later part of season and most nitrogen was relocated to tubers. The results suggest that an application of only 60 kg N ha-1 was sufficient to promote rapid canopy development and there were only small reductions in dry matter and nitrogen accumulation until late in the season when the canopy started to senesce as nitrogen supply diminished. Tuber yield, plant dry matter and nitrogen accumulation at maturity were related to crop nitrogen supply. Although application of the high rate, 120 N kg ha-1, resulted in a significant increase in dry matter accumulation, this was not reflected in the profit because the higher nitrogen application reduced dry matter content of tubers by 2.6% in 2000 and by 1.1% in 2001 relative to the use of 60 kg N ha-1. Apparent fertilizer nitrogen recovery values on a whole plant basis ranged from 53 to 75%. The proportion of fertilizer recovered in tubers clearly declined with increase in nitrogen supply.;

A 660-Kb deletion with antagonistic effects on fertility and milk production segregates at high frequency in Nordic Red cattle

DEFF Research Database (Denmark)

Kadri, Naveen Kumar; Sahana, Goutam; Charlier, Carole

2014-01-01

In dairy cattle, the widespread use of artificial insemination has resulted in increased selection intensity, which has led to spectacular increase in productivity. However, cow fertility has concomitantly severely declined. It is generally assumed that this reduction is primarily due to the nega......In dairy cattle, the widespread use of artificial insemination has resulted in increased selection intensity, which has led to spectacular increase in productivity. However, cow fertility has concomitantly severely declined. It is generally assumed that this reduction is primarily due...

Desired Fertility and Number of Children Born Across Time and Space.

Science.gov (United States)

Günther, Isabel; Harttgen, Kenneth

2016-02-01

Economists have often argued that high fertility rates are mainly driven by women's demand for children (and not by family planning efforts) with low levels of unwanted fertility across countries (and hence with little room for family planning efforts to reduce population growth). We study the relationship between wanted fertility and number of children born in a panel of 200 country-years controlling for country fixed effects and global time trends. In general, we find a close relationship between wanted and actual fertility, with one desired child leading to one additional birth. However, our results also indicate that in the last 20 years, the level of unwanted births has stayed at 2 across African countries but has, on average, decreased from 1 to close to 0 in other developing countries. Hence, women in African countries are less able to translate child preferences into birth outcomes than women in other developing countries, and forces other than fertility demand have been important for previous fertility declines in many developing countries. Family planning efforts only partially explain the observed temporal and spatial differences in achieving desired fertility levels.

Eye disease, the fertility decline, and the emergence of global income differences

DEFF Research Database (Denmark)

Andersen, Thomas B.; Dalgaard, Carl-Johan Lars; Selaya, Pablo

2014-01-01

This research advances and empirically establishes the hypothesis that regional variation in the historical incidence of eye disease has influenced the current global distribution of per capita income. By reducing work life expectancy, high historical eye disease incidence has served to diminish...... the incentive to accumulate skills, thereby delaying the fertility transition and the take-off to sustained economic growth. As a consequence of a differential timing of the take-off to growth, prompted by differences in the inherent return to skill formation, global income disparities have emerged....

Genetic variants determining survival and fertility in an adverse African environment

DEFF Research Database (Denmark)

Koopman, Jacob J E; Pijpe, Jeroen; Böhringer, Stefan

2016-01-01

Human survival probability and fertility decline strongly with age. These life history traits have been shaped by evolution. However, research has failed to uncover a consistent genetic determination of variation in survival and fertility. As an explanation, such genetic determinants have been...... selected in adverse environments, in which humans have lived during most of their history, but are almost exclusively studied in populations in modern affluent environments. Here, we present a large-scale candidate gene association study in a rural African population living in an adverse environment...

Association of pulse wave velocity and pulse pressure with decline in kidney function.

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Kim, Chang Seong; Kim, Ha Yeon; Kang, Yong Un; Choi, Joon Seok; Bae, Eun Hui; Ma, Seong Kwon; Kim, Soo Wan

2014-05-01

The association between arterial stiffness and decline in kidney function in patients with mild to moderate chronic kidney disease (CKD) is not well established. This study investigated whether pulse wave velocity (PWV) and pulse pressure (PP) are independently associated with glomerular filtration rate (GFR) and rapid decline in kidney function in early CKD. Carotid femoral PWV (cfPWV), brachial-ankle PWV (baPWV), and PP were measured in a cohort of 913 patients (mean age, 63±10 years; baseline estimated GFR, 84±18 mL/min/1.73 m(2) ). Estimated GFR was measured at baseline and at follow-up. The renal outcome examined was rapid decline in kidney function (estimated GFR loss, >3 mL/min/1.73 m(2) per year). The median follow-up duration was 3.2 years. Multivariable adjusted linear regression model indicated that arterial PWV (both cfPWV and baPWV) and PP increased as estimated GFR declined, but neither was associated with kidney function after adjustment for various covariates. Multivariable logistic regression analysis found that cfPWV and baPWV were not associated with rapid decline in kidney function (odds ratio [OR], 1.39, 95% confidence interval [CI], 0.41-4.65; OR, 2.51, 95% CI, 0.66-9.46, respectively), but PP was (OR, 1.22, 95% CI, 1.01-1.48; P=.045). Arterial stiffness assessed using cfPWV and baPWV was not correlated with lower estimated GFR and rapid decline in kidney function after adjustment for various confounders. Thus, PP is an independent risk factor for rapid decline in kidney function in populations with relatively preserved kidney function (estimated GFR ≥30 mL/min/1.73 m(2) ). ©2014 Wiley Periodicals, Inc.

Below Replacement-Level Fertility in Conditions of slow Social and Economic Development: A Review of the Evidence from South-India

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Minna Säävälä

2010-01-01

Full Text Available Demographic interest in the explanations of the first fertility transition has receded considerably during the last decade. Despite the empirical evidence of global convergence in fertility, there is still no consensus on the factors which explain the swiftness of the change in some contexts and its deceleration in some others. From the policy perspective, it remains pivotal to locate the factors that affect the momentum of fertility transition. In this essay the fast decline to below replacement-level period Total Fertility Rate in South India will be examined as an example of fertility transition despite slow social and/or economic development. The analysis is based on a literature review of empirical studies on the determinants of regional fertility differentials in India. Some southern states, most particularly Andhra Pradesh, manifest below replacement-level fertility (TFR 1.79 despite low average age at marriage even in Indian terms, the resilience of womens universal marriage, and heavy reliance on a terminal family planning method, female sterilization. The case of Andhra Pradesh shows that below-replacement level fertility can occur despite slow social development, widespread poverty and gender asymmetries. Geographical and social diffusion effects are partly responsible of the speed of the decline, although they are difficult to measure or test in the level of fertility decision-making.

Opting For Families: Recent Trends in the Fertility of Highly Educated Women. NBER Working Paper No. 15074

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Shang, Qingyan; Weinberg, Bruce A.

2009-01-01

Observers have argued about whether highly-educated women are opting out of their careers and for families. If so, it is natural to expect fertility to increase and, insofar as children are associated with lower employment, further declines in employment. This paper provides a comprehensive study of recent trends in the fertility of…

The historical fertility transition at the micro level: Southern Sweden 1815-1939

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Tommy Bengtsson

2014-02-01

Full Text Available Background: We know a great deal about the historical fertility transition at the macro level. The dominating focus on the macro level in previous research on the fertility transition means, however, that to a large extent we lack knowledge about details of the decline and empirical tests of the leading explanatory frameworks. Objective: Our aim is to explore socioeconomic fertility differentials in an industrializing community, to gain insight about the details and discuss possible mechanisms. The study starts well before industrialization and finishes at the end of the transition. Methods: We use longitudinal individual-level data from the Scanian Economic-Demographic Database, which contains demographic as well as socioeconomic information, including occupation, landholding, and income. In the analysis we use hazard regressions with shared frailty at the family level. Results: The transition involved not only parity-specific stopping but also spacing. While the upper social strata had higher fertility prior to the transition, they started to control their fertility earlier, by the 1880s, and also more consistently. Farmers, the middle class, and skilled workers followed in the decades after, and unskilled workers with some additional delay. Conclusions: These findings are partly inconsistent with several of the major explanations in the literature, such as mortality decline, increased female labor force participation, and a quantity-quality trade-off, but consistent with an innovation process where new ideas and attitudes about family limitation spread from the elite to other social groups. Comments: Further studies are required to empirically test the innovation-diffusion theory.

Family intentions and personal considerations on postponing childbearing in childless cohabiting and single women aged 35-43 seeking fertility assessment and counselling

DEFF Research Database (Denmark)

Birch Petersen, K; Hvidman, H W; Sylvest, R

2015-01-01

STUDY QUESTION: What characterizes childless women aged 35 years and above seeking fertility assessment and counselling in relation to their reproduction and are there significant differences between single and cohabiting women? SUMMARY ANSWER: Despite the women's advanced age and knowledge...... of the age-related decline in fecundity, 70% of the single women sought fertility assessment and counselling to gain knowledge regarding the possibility of postponing pregnancy. WHAT IS KNOWN ALREADY: Recent studies have indicated an increasing demand for ovarian reserve testing in women without any known......, smaller families than desired and declining fertility rates. STUDY DESIGN, SIZE, AND DURATION: Baseline data from a cross-sectional cohort study of 340 women aged 35-43 years examined at the Fertility Assessment and Counselling (FAC) Clinic at Copenhagen University Hospital from 2011 to 2014. The FAC...

Studies in utilization of fertilizer and soil nitrogen by carrots

International Nuclear Information System (INIS)

Moussa, A.G.; Markgraf, G.; Geissler, T.

1985-01-01

Pot experiments were conducted to determine the extent of fertilizer N utilization by carrots, using double-labelled 15 N-ammonium nitrate. The degree of soil N utilization was also studied. The residual effect of nitrogen in the individual variants was determined in spinach grown as succeeding crop. Under the experimental conditions, N utilization was highest at high water supply (100 % of water capacity). Due to the daily rhythm of pot watering to approximately 100 % of water capacity, gas exchange (air and oxygen) was ensured as well, providing optimum growth conditions. At medium nitrogen rates (12.5 g N/m 2 ), carrots took up 44.5 % of the fertilizer N on sand and 54.5 % on loess soil. When water supply decreased to 70 % of the water capacity, utilization of fertilizer N declined to 26 % on sand and 43.8 % on loess soil. Spinach grown as succeeding crop took up more soil N than fertilizer N. (author)

Intentions and attitudes towards parenthood and fertility awareness among Chinese university students in Hong Kong: a comparison with Western samples.

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Chan, C H Y; Chan, T H Y; Peterson, B D; Lampic, C; Tam, M Y J

2015-02-01

What are the levels of awareness regarding female fertility and the intentions and attitudes towards parenthood among Chinese university students in Hong Kong compared with their counterparts in the West? Chinese university students in Hong Kong were similarly over-optimistic about the age-related fertility decline, although they were less inclined to have children and undergo fertility treatment compared with their Western counterparts. Past studies of highly educated young adults in Europe and the USA have found that they are not sufficiently aware of the age-related decline in female fertility, and falsely believe that advanced reproductive treatments such as IVF will overcome fertility problems associated with age. Little is known about the perceptions of Chinese students in Hong Kong, a modernized Chinese city where the fertility rate is among the lowest in the world. An online cross-sectional survey of Chinese university students in Hong Kong was conducted in 2013. Results were compared with two similar studies in Sweden and the USA. A total of 367 university students in Hong Kong (275 female, 92 male; mean age 23) responded to an e-mail invitation to participate in an online survey. Intentions and attitudes towards parenthood and awareness regarding female fertility were assessed using the Swedish Fertility Awareness Questionnaire. Like their Western counterparts, a large proportion of Chinese university students underestimated the age-related fertility decline (92%) and overestimated the fertility treatment success rate (66%). However, they were less inclined to have children, were more aware of and less concerned with infertility and were less motivated to seek solutions in the event of a fertility problem. These comparisons were significant at P International comparisons warrant caution because the Hong Kong sample was older than the US sample (mean age 20), but not older than the Sweden sample (mean age 24). While this study was consistent with past

Can arbuscular mycorrhiza and fertilizer management reduce phosphorus runoff from paddy fields?

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Zhang, Shujuan; Wang, Li; Ma, Fang; Zhang, Xue; Li, Zhe; Li, Shiyang; Jiang, Xiaofeng

2015-07-01

Our study sought to assess how much phosphorus (P) runoff from paddy fields could be cut down by fertilizer management and inoculation with arbuscular mycorrhizal fungi. A field experiment was conducted in Lalin River basin, in the northeast China: six nitrogen-phosphorus-potassium fertilizer levels were provided (0, 20%, 40%, 60%, 80%, and 100% of the recommended fertilizer supply), with or without inoculation with Glomus mosseae. The volume and concentrations of particle P (PP) and dissolved P (DP) were measured for each runoff during the rice growing season. It was found that the seasonal P runoff, including DP and PP, under the local fertilization was 3.7 kg/ha, with PP, rather than DP, being the main form of P in runoff water. Additionally, the seasonal P runoff dropped only by 8.9% when fertilization decreased by 20%; rice yields decreased with declining fertilization. We also found that inoculation increased rice yields and decreased P runoff at each fertilizer level and these effects were lower under higher fertilization. Conclusively, while rice yields were guaranteed arbuscular mycorrhizal inoculation and fertilizer management would play a key role in reducing P runoff from paddy fields. Copyright © 2015. Published by Elsevier B.V.

Insights into the Regulation of Rhizosphere Bacterial Communities by Application of Bio-organic Fertilizer in Pseudostellaria heterophylla Monoculture Regime

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Linkun Wu

2016-11-01

Full Text Available The biomass and quality of Pseudostellariae heterophylla suffers a significant decline under monoculture. Since rhizosphere microbiome plays crucial roles in soil health, deep pyrosequencing combined with qPCR was applied to characterize the composition and structure of soil bacterial community under monoculture and different amendments. The results showed compared with the first-year planted (FP, second-year monoculture of P. heterophylla (SP led to a significant decline in yield and resulted in a significant increase in Fusarium oxysporum but a decline in Burkholderia spp. Bio-organic fertilizer (MT formulated by combining antagonistic bacteria with organic matter could significantly promote the yield by regulating rhizosphere bacterial community. However, organic fertilizer (MO without antagonistic bacteria could not suppress Fusarium wilt. Multivariate statistics analysis showed a distinct separation between the healthy samples (FP and MT and the unhealthy samples (SP and MO, suggesting a strong relationship between soil microbial community and plant performance. Furthermore, we found the application of bio-organic fertilizer MT could significantly increase the bacterial community diversity and restructure microbial community with relatively fewer pathogenic F. oxysporum and more beneficial Burkholderia spp. In conclusion, the application of novel bio-organic fertilizer could effectively suppress Fusarium wilt by enriching the antagonistic bacteria and enhancing the bacterial diversity.

Fertility behavior in developing economies: an investment approach.

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Chernichovsky, D

1982-01-01

By studying intergenerational benefits from children, this paper shows that the economic analysis of fertility behavior in developing economics can provide a systematic discussion of this behavior. The major hypotheses set forth are: 1) the effect of income on fertility depends on the source and timing of income; 2) in a lifetime context, parents, or would-be parents, who have higher incomes at young ages compared with the income they anticipate at old age, are expected to have a higher demand for children; and 3) the reverse of the latter is predicted for parents who anticipate relatively higher incomes at old age. These hypotheses follow the idea that, in the absence of other appropriate means for intertemporal transfers of wealth, parents even out the lifetime welfare through fertility behavior. Under these circumstances, fertility rates are expected to increase in communities where children abandon their traditional commitments to their aging parents, as may happen during periods of economic and cultural transition. A decline in mortality rates will induce lower fertility. This model suggests that a tax-financed social security scheme along with family planning will be conducive to a reduction in fertility. A test on data from an Indian village in 1968-69 suggests that in a traditional setting there is a correlation between household welfare, measured by income or assets, and the presence of grown children. Income has a positive effect on fertility when the parents' incomes comes from labor rather than human and nonhuman capital which provides income at later stages of life. Longitudinal data depicting income, savings, and fertility patterns over time should prove more promising in exploring the issues discussed.

Non-genetic factors affecting fertility traits in South African Holstein ...

African Journals Online (AJOL)

Profitable milk production and genetic improvement in dairy herds depend largely on fertile cows calving annually to initiate a new lactation period. Over the last 30 years, several studies have indicated a decline in the reproductive performance of dairy cows. From the perspectives of many farmers and veterinarians, the ...

Syndromes of rapidly progressive cognitive decline-our experience

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Sadanandavalli Retnaswami Chandra

2017-01-01

Full Text Available Background: Dementias are fairly slowly progressive degenerative diseases of brain for which treatment options are very less and carry a lot of burden on family and society. A small percentage of them are rapidly progressive and mostly carry a different course outcome. However, there are no definite criteria other than the time line for these patients. Aims: The aim of this was to identify and categorize the causes and course of rapidly progressive dementias seen in our center. Settings and Design: Patients who presented with rapid deterioration of cognitive functions within weeks to 1 year between 2011 and December 2016 were evaluated. Patients and Methods: All patients underwent all mandatory tests for dementia including brain imaging. Complete vasculitis workup, autoimmune encephalitis profile including Voltage Gated Potassium Channel, N-methyl-D-aspartic acid receptor, glutamic acid-decarboxylase, thyroid-peroxidase antibody, cerebrospinal fluid, and other special tests such as duodenal biopsy and paraneoplastic workup were done based on clinical indications. Results and Conclusions: Out of 144 patients 42 had immune-mediated encephalopathy, 18 had Creutzfeldt-Jakob disease, 3 had Vitamin B12 deficiency, 63 had infection with neurocysticercosis, 7 had tuberculosis, 2 had HIV, 1 had herpes simplex encephalitis, 1 had neurosyphilis, 1 Whipples disease, 1 had Subacute Sclerosing Panencephalitis, 1 had Mass lesion, 3 had Frontotemporal dementia, and 3 had small vessel disease. Good majority of these patients have infective and immune-mediated causes and less number belong to degenerative group. Therefore, caution is needed to look for treatable cause as it carries a different treatment options and outcome.

The Role of socioeconomic factors in fertility of Umuahia women in ...

African Journals Online (AJOL)

Rapid population growth arising from high fertility has been argued as being disadvantageous to the economic growth of countries especially the developing country like Nigeria. This paper examines the role of socioeconomic factors in fertility. The study elicited information from 500 women of the reproductive age of 15-49 ...

Decline of Ohia (Metrosideros polymorpha) in Hawaii: a review

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Charles S. Hodges; Ken T. Adee; John D. Stein; Hulton B. Wood; Robert D. Doty

1986-01-01

Portions of the ohia (Metrosideros polymorpha) forests on the windward slopes of Mauna Loa and Mauna Kea on the island of Hawaii began dying in 1952. Little mortality has occurred since 1972. About 50,000 ha are affected by the decline. Individual trees exhibit several symptoms, from slow progressive dieback to rapid death. Seven types of decline...

Development of Malaysian women fertility index: Evidence from Shannon's entropy

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Jalil, Wan Aznie Fatihah Wan Abd; Sharif, Shamshuritawati

2017-11-01

A fertility rate is a measure of the average number of children a woman will have during her childbearing years. Malaysia is now facing a population crisis and the fertility rate continues to decline. This situation will have implications for the age structure of the population where percentages of senior citizens are higher than percentages of people aged below 5 years old. Malaysia is expected to reach aging population status by the year 2035. As the aging population has a very long average life expectancy, the government needs to spend a lot on medical costs for senior citizens and need to increase budgets for pensions. The government may be required to increase tax revenues to support the growing older population. The falling fertility rate requires proper control by relevant authorities, especially through planning and implementation of strategic and effective measures. Hence, this paper aims to develop a fertility index using Shannon's entropy method. The results show that Selangor, Johor, and Sarawak are among the states with the highest values of the fertility index. On the other end of the spectrum, Terengganu, W.P. Labuan, and Perlis are ranked in the last positions according to the fertility index. The information generated from the results in this study can be used as a primary source for the government to design appropriate policies to mitigate dwindling fertility rates among Malaysian women.

Ovarian fluid mediates the temporal decline in sperm viability in a fish with sperm storage.

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Clelia Gasparini

Full Text Available A loss of sperm viability and functionality during sperm transfer and storage within the female reproductive tract can have important fitness implications by disrupting fertilization and impairing offspring development and survival. Consequently, mechanisms that mitigate the temporal decline in sperm function are likely to be important targets of selection. In many species, ovarian fluid is known to regulate and maintain sperm quality. In this paper, we use the guppy Poecilia reticulata, a highly polyandrous freshwater fish exhibiting internal fertilization and sperm storage, to determine whether ovarian fluid (OF influences the decline in sperm viability (the proportion of live sperm in the ejaculate over time and whether any observed effects depend on male sexual ornamentation. To address these questions we used a paired experimental design in which ejaculates from individual males were tested in vitro both in presence and absence of OF. Our results revealed that the temporal decline in sperm viability was significantly reduced in the presence of OF compared to a saline control. This finding raises the intriguing possibility that OF may play a role in mediating the decline in sperm quality due to the deleterious effects of sperm ageing, although other possible explanations for this observation are discussed. Interestingly, we also show that the age-related decline in sperm viability was contingent on male sexual ornamentation; males with relatively high levels of iridescence (indicating higher sexual attractiveness exhibited a more pronounced decline in sperm viability over time than their less ornamented counterparts. This latter finding offers possible insights into the functional basis for the previously observed trade-off between these key components of pre- and postcopulatory sexual selection.

Plot-size for 15N-fertilizer recovery studies by tanzania-grass

International Nuclear Information System (INIS)

Martha Junior, Geraldo Bueno; Trivelin, Paulo Cesar Ocheuze; Corsi, Moacyr

2009-01-01

The understanding of the N dynamics in pasture ecosystems can be improved by studies using the 15 N tracer technique. However, in these experiments it must be ensured that the lateral movement of the labeled fertilizer does not interfere with the results. In this study the plot-size requirements for 15 N-fertilizer recovery experiments with irrigated Panicum maximum cv. Tanzania was determined. Three grazing intensities (light, moderate and intensive grazing) in the winter, spring and summer seasons were considered. A 1 m 2 plot-size, with a grass tussock in the center, was adequate, irrespective of the grazing intensity or season of the year. Increasing the distance from the area fertilized with 15 N negatively affected the N derived from fertilizer (Npfm) recovered in herbage.The lowest decline in Npfm values were observed for moderate and light grazing intensities. This fact might be explained by the vigorous growth characteristics of these plants. Increasing the grazing intensity decreased the tussock mass and, the smaller the tussock mass, the greater was the dependence on fertilizer nitrogen. (author)

High-resolution inventory of ammonia emissions from agricultural fertilizer in China from 1978 to 2008

Science.gov (United States)

Xu, P.; Liao, Y. J.; Lin, Y. H.; Zhao, C. X.; Yan, C. H.; Cao, M. N.; Wang, G. S.; Luan, S. J.

2016-02-01

The quantification of ammonia (NH3) emissions is essential to the more accurate quantification of atmospheric nitrogen deposition, improved air quality and the assessment of ammonia-related agricultural policy and climate mitigation strategies. The quantity, geographic distribution and historical trends of these emissions remain largely uncertain. In this paper, a new Chinese agricultural fertilizer NH3 (CAF_NH3) emissions inventory has been compiled that exhibits the following improvements: (1) a 1 × 1 km gridded map on the county level was developed for 2008; (2) a combined bottom-up and top-down method was used for the local correction of emission factors (EFs) and parameters; (3) the temporal patterns of historical time trends for 1978-2008 were estimated and the uncertainties were quantified for the inventories; and (4) a sensitivity test was performed in which a province-level disaggregated map was compared with CAF_NH3 emissions for 2008. The total CAF_NH3 emissions for 2008 were 8.4 TgNH3 yr-1 (a 6.6-9.8 Tg interquartile range). From 1978 to 2008, annual NH3 emissions fluctuated with three peaks (1987, 1996 and 2005), and total emissions increased from 3.2 to 8.4 Tg at an annual rate of 3.0 %. During the study period, the contribution of livestock manure spreading increased from 37.0 to 45.5 % because of changing fertilization practices and the rapid increase in egg, milk, and meat consumption. The average contribution of synthetic fertilizer, which has a positive effect on crop yields, was approximately 38.3 % (minimum: 33.4 %; maximum: 42.7 %). With rapid urbanization causing a decline in the rural population, the contribution of the rural excrement sector varied widely between 20.3 % and 8.5 %. The average contributions of cake fertilizer and straw returning were approximately 3.8 and 4.5 %, respectively, thus small and stable. Collectively, the CAF_NH3 emissions reflect the nation's agricultural policy to a certain extent. An effective approach to

Effects of combined application of organic and inorganic fertilizers plus nitrification inhibitor DMPP on nitrogen runoff loss in vegetable soils.

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Yu, Qiaogang; Ma, Junwei; Zou, Ping; Lin, Hui; Sun, Wanchun; Yin, Jianzhen; Fu, Jianrong

2015-01-01

The application of nitrogen fertilizers leads to various ecological problems such as large amounts of nitrogen runoff loss causing water body eutrophication. The proposal that nitrification inhibitors could be used as nitrogen runoff loss retardants has been suggested in many countries. In this study, simulated artificial rainfall was used to illustrate the effect of the nitrification inhibitor DMPP (3,4-dimethyl pyrazole phosphate) on nitrogen loss from vegetable fields under combined organic and inorganic nitrogen fertilizer application. The results showed that during the three-time simulated artificial rainfall period, the ammonium nitrogen content in the surface runoff water collected from the DMPP application treatment increased by 1.05, 1.13, and 1.10 times compared to regular organic and inorganic combined fertilization treatment, respectively. In the organic and inorganic combined fertilization with DMPP addition treatment, the nitrate nitrogen content decreased by 38.8, 43.0, and 30.1% in the three simulated artificial rainfall runoff water, respectively. Besides, the nitrite nitrogen content decreased by 95.4, 96.7, and 94.1% in the three-time simulated artificial rainfall runoff water, respectively. A robust decline in the nitrate and nitrite nitrogen surface runoff loss could be observed in the treatments after the DMPP addition. The nitrite nitrogen in DMPP addition treatment exhibited a significant low level, which is near to the no fertilizer application treatment. Compared to only organic and inorganic combined fertilizer treatment, the total inorganic nitrogen runoff loss declined by 22.0 to 45.3% in the organic and inorganic combined fertilizers with DMPP addition treatment. Therefore, DMPP could be used as an effective nitrification inhibitor to control the soil ammonium oxidation in agriculture and decline the nitrogen runoff loss, minimizing the nitrogen transformation risk to the water body and being beneficial for the ecological environment.

General aspects of fertility and infertility.

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Damario, Mark A

2014-01-01

Fertility rates have been declining in most Western nations over the past several decades, although it is not entirely clear if an increased rate of infertility substantially contributes to this. As compared to other species, the reproductive efficiency of humans is relatively low. Factors related to fertility include age, exposure to sexually transmitted diseases, frequency of intercourse, coital timing, as well as diet and lifestyle habits. Infertility is considered a disease due to its major disruption of major organ systems and life functions. An infertility evaluation is recommended after 12 months or more of regular, unprotected intercourse and may be considered after 6 months for those female patients over the age of 35 or with other known abnormalities. A proper infertility evaluation is a comprehensive examination of possibly identifiable infertility factors of both female and male partners, lending itself to the most appropriate and potentially effective treatment.

Consequences of Enduring Low Fertility – A German Case StudyDemographic Projections and Implications for Different Policy Fields

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Martin Bujard

2015-06-01

Full Text Available Der Originalbeitrag in deutscher Sprache ist verfügbar unter: Bd. 40 (2015: Ausgewählte deutsche Beiträge.Compared to all other countries in the world, Germany has been a “low-fertility country” for a longer period: the total fertility rate has been below 1.5 for four decades. Being the first to experience this development, a case study of Germany allows analysing the consequences of an enduring birth decline. In Germany, low fertility is also an increasingly big issue in politics as well as science, especially due to its extensive consequences on several policy fields that already become visible. However, the assessment of the consequences differs tremendously when it comes either to its intensity or to the question whether ageing or rather population decline is the more severe problem. Differentiated by these two processes, this article combines demographic analysis with the assessment of the consequences for different policy fields such as pensions, health, the economy, the labour market, culture, the EU, international relations and the party system.For all these policy fields, the consequences are serious, and partly ambivalent but overall negative. The occurrence of the consequences and the different policy options how to deal with these consequences differ considerably between the policy fields. Ageing is a more severe problem than shrinking, because the severe changes in the age structure in the social security system that will take place until 2040 apply to most Germans and are inevitable. On the other hand, the population decline can still be avoided demographically and does not affect all inhabitants negatively. Regarding the consequences of a declining population, one has to differentiate between an individual and a national perspective. National consequences are rather negative due to a decline of international influence and power, especially within the European Union. The study also demonstrates that the long

Impacts of enhanced fertilizer applications on tropospheric ozone and crop damage over sub-Saharan Africa

Science.gov (United States)

Huang, Yaoxian; Hickman, Jonathan E.; Wu, Shiliang

2018-05-01

Fertilizer-induced nitrogen oxides (NOx) emissions in sub-Saharan Africa are expected to increase substantially in the coming decades, driven by increasing application of fertilizers to increase crop yields in an effort to attain food security across the continent. In many parts of sub-Saharan Africa, surface ozone (O3) is sensitive to increasing atmospheric concentrations of NOx. In this study, we employ the GEOS-Chem chemical transport model to conduct a preliminary investigation of the impacts on O3 air quality and the consequential crop damage associated with increasing fertilizer-induced NOx emissions in sub-Saharan Africa. Our simulation results, constrained by field NO flux measurements for the years 2011 and 2012 in response to a variety of fertilizer application rates in western Kenya, show that the enhancements in NO flux with fertilizer application rate of 150 kg N ha-1 can increase surface NOx and O3 concentrations by up to 0.36 and 2.8 ppbv respectively during the growing season. At the same time, accumulated O3 exposure during the crop growing season (expressed as AOT40 values) could increase by up to 496 ppb h, leading to crop yield decline of about 0.8% for O3-sensitive crops. Our results suggest that, when accounting for the consequential impacts on surface O3 air quality and crop damage over sub-Saharan Africa, agricultural intensification is possible without substantial impacts on crop productivity because the relatively small decline of crop yield resulting from O3 damage appears unlikely to outweigh the gain in crop yield from fertilization.

Interactions of socioeconomic determinants, offspring sex preference, and fertility behaviour

Directory of Open Access Journals (Sweden)

Zongli Tang

2011-12-01

society. However, these two factors do not work on husbands in the same way, demonstrating men’s inflexible attitudes toward gender roles in the family and in society. Son preference exerts a positive impact on American-Chinese fertility and prevents further decline; still, this influence has been diminishing since 1990, as observed in this study.

Effect of different split applications of npk fertilizer on growthand ...

African Journals Online (AJOL)

Declining inherent soil nutrient, poor grain yield of maize, delayed supply and high cost of inorganic fertilizer, call for proper timing of application, to optimize the use of this scarce resource in maize production in Nigeria. A field experiment was carried out in the 2007 and 2008 cropping seasons in the University of ...

Fertility and migration in the heart of the industrial revolution.

Science.gov (United States)

Oris, M

1996-01-01

This study examines demographic growth and change in Tilleur in the valley of Meuse in Belgium during 1807-80 during the process of industrialization and urbanization. The proportion of immigrants (foreigners and Flemings) increased from 15% in 1807 to 65% in 1856. After 1856, population and industrial growth stabilized. During 1856-66 the proportion of natives stabilized, and the proportion of Flemings increased. It is argued that in Tilleur there were two phases: a foundation phase of industrial and population growth and a phase of maturation with decreased non-native population and greater similarity between groups. Immigrants contributed to the birth rate in greater proportions than their proportion in the population of Tilleur. During 1847-66 native population increased annually from 2.4% to 3.8%. Migrants' annual increases were diminished by the effects of mortality but expanded by the influence of in-migration. During 1857-66 the proportion of foreigners declined and marked the transition to a new phase. During 1830-66 the sex ratio grew from 93 to 119. During the Industrial Revolution in Tilleur, women shifted from outnumbering to undernumbering men. The iron and coal in the region attracted men. The sex ratio among the Flemish was 214 in 1866. In 1830 the proportion of fertile women was higher among immigrants and declined thereafter. Age at marriage rose for natives and declined for immigrants. The native population structure by sex, age, and marriage did not favor the birth rate. During 1866-80 the birth rate of foreign immigrants and rural natives declined, the birth rate of natives doubled, and the gap between these two groups narrowed. The changes among immigrants during the foundation phase led to fertility decline in the maturation phase. Marriage and migration interactions linked the industrial revolution with the demographic transition.

Global change and the decline of coral reefs

OpenAIRE

Strasser, A.

1999-01-01

Ever since coral reefs exist, changing environmental conditions have periodically led to their decline. However, within the perspective of geological time-spans, corals have always managed to re-install themselves. Today, human activity has enhanced stress factors and added new ones that cause a rapid and (on the human time-scale) irreversible decline of many reef ecosystems. The reasons for the disturbance of these complex communities are multiple, but global warming is a k...

Clinical outcomes of fertility-sparing treatments in young patients with epithelial ovarian carcinoma.

Science.gov (United States)

Hu, Jun; Zhu, Li-rong; Liang, Zhi-qing; Meng, Yuan-guang; Guo, Hong-yan; Qu, Peng-peng; Ma, Cai-ling; Xu, Cong-jian; Yuan, Bi-bo

2011-10-01

To assess the clinical outcomes of fertility-sparing treatments in young patients with epithelial ovarian carcinoma (EOC). A retrospective study of young EOC inpatients (≤40 years old) was performed during January 1994 and December 2010 in eight institutions. Data were analyzed from 94 patients treated with fertility-sparing surgery with a median follow-up time of 58.7 months. As histologic grade increased, overall survival (OS) and disease-free survival (DFS) of patients receiving fertility-sparing surgery declined. Neither staging surgery nor laparoscopy of early stage EOC with conservative surgery had a significant effect on OS or DFS. Normal menstruation recommenced after chemotherapy in 89% of the fertility-sparing group. Seventeen pregnancies among twelve patients were achieved by the end of the follow-ups. Fertility-sparing treatment for patients with EOC Stage I Grade 1 could be cautiously considered for young patients. The surgical procedure and surgical route might not significantly influence the prognosis. Standard chemotherapy is not likely to have an evident impact on ovarian function or fertility in young patients.

Effects of Fertilization on Tomato Growth and Soil Enzyme Activity

Science.gov (United States)

Mu, Zhen; Hu, Xue-Feng; Cheng, Chang; Luo, Zhi-qing

2015-04-01

To study the effects of different fertilizer applications on soil enzyme activity, tomato plant growth and tomato yield and quality, a field experiment on tomato cultivation was carried out in the suburb of Shanghai. Three fertilizer treatments, chemical fertilizer (CF) (N, 260 g/kg; P, 25.71g/kg; K, 83.00g/kg), rapeseed cake manure (CM) (N, 37.4 g/kg; P, 9.0 g/kg; K, 8.46 g/kg), crop-leaf fermenting manure (FM) (N, 23.67 g/kg; P, 6.39 g/kg; K 44.32 g/kg), and a control without using any fertilizers (CK), were designed. The total amounts of fertilizer application to each plot for the CF, CM, FM and CK were 0.6 kg, 1.35 kg, 3.75 kg and 0 kg, respectively, 50% of which were applied as base fertilizer, and another 50% were applied after the first fruit picking as top dressing. Each experimental plot was 9 m2 (1 m × 9 m) in area. Each treatment was replicated for three times. No any pesticides and herbicides were applied during the entire period of tomato growth to prevent their disturbance to soil microbial activities. Soil enzyme activities at each plot were constantly tested during the growing period; the tomato fruit quality was also constantly analyzed and the tomato yield was calculated after the final harvesting. The results were as follows: (1) Urease activity in the soils treated with the CF, CM and FM increased quickly after applying base fertilizer. That with the CF reached the highest level. Sucrase activity was inhibited by the CF and CM to some extent, which was 32.4% and 11.2% lower than that with the CK, respectively; while that with the FM was 15.7% higher than that with the CK. Likewise, catalase activity with the CF increased by 12.3% - 28.6%; that with the CM increased by 87.8% - 95.1%; that with the FM increased by 86.4% - 93.0%. Phosphatase activity with the CF increased rapidly and reached a maximum 44 days after base fertilizer application, and then declined quickly. In comparison, that with the CM and FM increased slowly and reached a maximum

A Long-term Forest Fertilization Experiment to Understand Ecosystem Responses to Atmospheric Nitrogen Deposition

Science.gov (United States)

Baron, J.; Advani, S. M.; Allen, J.; Boot, C.; Denef, K.; Denning, S.; Hall, E.; Moore, J. C.; Reuth, H.; Ryan, M. G.; Shaw, E.

2016-12-01

Long-term field experiments can reveal changes in ecosystem processes that may not be evident in short-term studies. Short-term measurements or experiments may have narrower objectives or unrealistic treatments in order to see a change, whereas long-term studies can reveal complex interactions that take longer to manifest. We report results from a long-term experiment (1996 to present) in subalpine forests to simulate the consequences of sustained atmospheric nitrogen (N) deposition. Loch Vale watershed in Rocky Mountain National Park, the location of the experiment, has received an order of magnitude greater atmospheric N deposition than estimated background since mid-20th Century. Augmenting that, in 1996 we began adding 25 kg NH4NO3 ha-1 yr-1 to three 30m x 30m old-growth Engelmann spruce and subalpine fir plots. Treated stands were matched by nearby controls. N addition caused rapid leaching of nitrate and cations from soils, and increased N mineralization and nitrification rates. These observations in the fertilized plots have been sustained over time. Soluble aluminum concentrations do not differ significantly between fertilized and control plots, but treated soils are now markedly more acidic (pH of 4.7) than original soil and controls (pH of 5.1); further acidification might increase aluminum leaching. Effects on soil carbon were complex, mediated by reductions in total microbial biomass, decreases in arbuscular mychorrizal and saprotropic fungi, and increased potential rates of N enzyme degrading activities. Initial soil C:N of 24 was lower than similar soils in low N deposition stands (C:N of 36). The C:N declined to 22 with treatment. Fertilized plots lost 11% soil C, but the mechanism is unclear. We did not measure changes in C inputs from litter, microbial biomass, or plant uptake, but there was no change in summer CO2 flux, measured in 2003, 2004, and 2014. Leaching of DOC from fertilized plots was elevated throughout the experiment, providing one

A 660-Kb Deletion with Antagonistic Effects on Fertility and Milk Production Segregates at High Frequency in Nordic Red Cattle

DEFF Research Database (Denmark)

Kadri, Naveen Kumar; Sahana, Goutam; Charlier, Carole

The spectacular increase in productivity of dairy cattle has been accompanied by a decline in fertility. It is assumed that this reduction is due to the negative energy balance of high producing cows. We herein describe the dissection of a fertility QTL in Nordic Red cattle to a 660-Kb deletion...

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

Science.gov (United States)

Vassard, Ditte; Lallemant, Camille; Nyboe Andersen, Anders; Macklon, Nick; Schmidt, Lone

2016-06-27

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. 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. 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 starts to decline around 25-30 years. Men had significantly lower fertility awareness. Women who underestimated the impact of age on female fertility were significantly more likely to have a desire or attempted their first child at a higher age. Even though the majority were aware of the age-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 for women and men in order to increase the population's knowledge of fertility and risk factors for infertility.

Effects of fertilizers used in agricultural fields on algal blooms

DEFF Research Database (Denmark)

Chakraborty, Subhendu; Tiwari, P. K.; Sasmal, S. K.

2017-01-01

of factors and from observation it is difficult to identify the most important one. In the present paper, using a mathematical model we compare the effects of three human induced factors (fertilizer input in agricultural field, eutrophication due to other sources than fertilizers, and overfishing......) on the bloom dynamics and DO level. By applying a sophisticated sensitivity analysis technique, we found that the increasing use of fertilizers in agricultural field causes more rapid algal growth and decreases DO level much faster than eutrophication from other sources and overfishing. We also look...... at the mechanisms how fertilizer input rate affects the algal bloom dynamics and DO level. The model can be helpful for the policy makers in determining the influential factors responsible for the bloom formation....

Interactions of Socioeconomic Determinants, Offspring Sex Preference and Fertility Behavior

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Paul M. Sharp

2011-01-01

Full Text Available Using path anaysis and the 5% PUMS data of the 1990 and 2000 censuses, this study examines 1 the correlation between Chinese-American sex preference for children and their fertility behavior, and 2 the interaction between the sex preference and its socioeconomic determinants. Of normative and non-normative factors investegated in this study, offspring sex preference is the greatest stimulus to Chinese fertility. Of socioeconomic variables, women’s educational attainment plays a primary role in depressing the impact of son preference in addition to their increasing stay in the host society. However, these two factors do not work on their husbands in the same way, demonstrating men’s inflexible attitudes toward gender roles in the family and in society. Son preference exerts positive impact on American-Chinese fertility and prevent from further decline. Yet, the influence has been diminishing since 1990 as observed in this study.

Were the Victorians cleverer than us? The decline in general intelligence estimated from a meta-analysis of the slowing of simple reaction time

NARCIS (Netherlands)

Woodley, M.A.; te Nijenhuis, J.; Murphy, R.

2013-01-01

The Victorian era was marked by an explosion of innovation and genius, per capita rates of which appear to have declined subsequently. The presence of dysgenic fertility for IQ amongst Western nations, starting in the 19th century, suggests that these trends might be related to declining IQ. This is

Swedish high school students' knowledge and attitudes regarding fertility and family building

Directory of Open Access Journals (Sweden)

Ekelin Maria

2012-03-01

Full Text Available Abstract Background Infertility is a serious problem for those who suffer. Some of the risks for infertility are preventable and the individual should therefore have knowledge of them. The purposes of this study were to investigate high-school students' knowledge about fertility, plans for family building and to compare views and knowledge between female and male students. Methods A questionnaire containing 34 items was answered by 274 students. Answers from male and female students were compared using student's t-test for normally distributed variables and Mann-Whitney U-test for non-normal distributions. The chi-square test was used to compare proportions of male and female students who answered questions on nominal and ordinal scales. Differences were considered as statistically significant at a p-value of 0.05. Results Analyses showed that 234 (85% intended to have children. Female students felt parenthood to be significantly more important than male students: p = 0.01. The mean age at which the respondents thought they would like to start to build their family was 26 (± 2.9 years. Men believed that women's fertility declined significantly later than women did: p = 0.01. Women answered that 30.7% couples were involuntarily infertile and men answered 22.5%: p = 0.01. Females thought it significantly more likely that they would consider IVF or adoption than men, p = 0.01. Men felt they were more likely to abstain from having children than women: p = 0.01. Women believed that body weight influenced fertility significantly more often than men: p = 0.01 and men believed significantly more often that smoking influenced fertility: p = 0.03. Both female and male students answered that they would like to have more knowledge about the area of fertility. Conclusions Young people plan to start their families when the woman's fertility is already in decline. Improving young people's knowledge about these issues would give them more opportunity to take

Economic development and family size.

Science.gov (United States)

Rios, R J

1991-01-01

The demographic transition in Latin America has resulted in increased family size rather than the Western European model of reduced family size. In 1905, both fertility and mortality were high in Latin America, but mortality declined more rapidly in Latin America than in Europe. In 1905, the crude birth rate for 15 selected countries averaged 44/1000 population. Western fertility at a comparable transition point was much lower at 30/1000. Between 1905 and 1960, fertility declines were evident in Uruguay, Argentina, Cuba, and Chile. Between 1960 and 1985, fertility declines appeared in Costa Rica, Panama, Brazil, and Colombia. Fertility declines were smaller in the other Latin American countries. Crude birth rates declined markedly by 1985 but may overestimate fertility decline, which is more accurately measured by standardized birth rates. Fertility decline was evident in Argentina, Chile, and Costa Rica for standardized birth rates, survivorship ratio, and births surviving past the age of 15 years. Theoretically, families are expected to reduce family size when survivorship is assured; when mortality is 25%, only four children need be planned instead of six when mortality is 50%. A result of falling mortality is a cheaper cost of producing children, which may stimulate parents to raise bigger families. Western fertility decline has been attributed to mortality decline, urbanization, increased female labor force participation, rising wages, and more efficient contraception. Comparable economic development in Latin America has not resulted in large enough changes to encourage family size limitation. A table of fertility and economic indicators for selected countries in Latin America and Europe reflects the inverse relationship between income growth, urban growth, and growth in female educational status and fertility. The regression equation explains 60% of the variation in fertility rates among Latin American countries. Explanatory power increases to 75% when female

Urbanization and the Change of Fertilizer Use Intensity for Agricultural Production in Henan Province

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Li Jiang

2016-02-01

Full Text Available China’s urbanization has resulted in significant changes in agricultural land use. However, understanding of the linkages between urbanization and fertilizer use intensity is limited. Using county-level panel data for Henan Province, 1995–2008 and panel econometric models, we investigate the impact of urbanization and other socioeconomic factors on fertilizer use intensity, with a focus on the two key processes related to urbanization—shrinking agricultural land area and increasing urban wages. Our results show that declining agricultural land per capita is associated with greater fertilizer use intensity. Urban wages is positively correlated with fertilizer use intensity. We also find that GDP per capita and per capita expenditure of government for agriculture both positively contribute to the increase of fertilizer use intensity, which is consistent with expectations. Our results imply that other than land conversion, urbanization contains some positive influences on land use sustainability. However, on the other hand, urbanization contributes to agriculture-based environmental pollution by increasing the level of fertilizer use in agricultural production.

Some economic consequences of an ageing and declining population in Denmark.

Science.gov (United States)

Leeson, G W

1983-01-01

Figures for 1981 indicate that Denmark has a fertility level of 1.45 which has been below replacement level since 1968. In that same time period, natural increase has decreased from over 27,000 in 1968 to only 1354 in 1980 and a negative natural increase in 1981 with deaths outnumbering births by 3001. Even during the depression in the 1930's, net population increase was between 6-9/1000 with a fertility level which hovered around replacement level. At that time, the number of females in the childbearing ages was enough to provide population growth, whereas the number is much less today. Population increase is only 0.3/1000. The national population projections for Denmark for 1981-2010 assume an increase in the fertility level from 1.45-1.70 by 1991 after which it remains constant. The number of 20-39 year olds increased steadily until 1945 after which there was a decline as the cohorts from periods with low fertility levels entered this age group, but this was again followed by a steady increase to the present day. The number of females aged 0-39 years is expected to decrease in all age groups to the year 2000. Those aged 40-59 increased in numbers from 1920 to the mid 1960s, since then they have decreased in number, but an increase is forcast for the remainder of the century. The number of elderly females also increased steadily from 1930-80, from about 200,000 to over 550,000; this is expected to continue until 1990 when a short-term decline will set in. Regarding the economic and social consequences of these trends, it is shown that the present decline in fertility has its origins in a period of low unemployment and its negative growth while there was still relatively low unemployment and economic growth. In 1973 the unemployed rate was 0.9% of the work force and this rose to 9.2% in 1981. The Danish population has aged from one with 1/4 million people aged 60 and over at the turn of the century to about 1 million of that age today. Also, the aged themselves

Pregnancy outcomes decline in recipients over age 44: an analysis of 27,959 fresh donor oocyte in vitro fertilization cycles from the Society for Assisted Reproductive Technology.

Science.gov (United States)

Yeh, Jason S; Steward, Ryan G; Dude, Annie M; Shah, Anish A; Goldfarb, James M; Muasher, Suheil J

2014-05-01

To use a large and recent national registry to provide an updated report on the effect of recipient age on the outcome of donor oocyte in vitro fertilization (IVF) cycles. Retrospective cohort study. United States national registry for assisted reproductive technology. Recipients of donor oocyte treatment cycles between 2008 and 2010, with cycles segregated into five age cohorts: ≤34, 35 to 39, 40 to 44, 45 to 49, and ≥50 years. None. Implantation, clinical pregnancy, live-birth, and miscarriage rates. In donor oocyte IVF cycles, all age cohorts ≤39 years had similar rates of implantation, clinical pregnancy, and live birth when compared with the 40- to 44-year-old reference group. Patients in the two oldest age groups (45 to 49, ≥50 years) experienced statistically significantly lower rates of implantation, clinical pregnancy, and live birth compared with the reference group. Additionally, all outcomes in the ≥50-year-old group were statistically significantly worse than the 45- to 49-year-old group, demonstrating progressive decline with advancing age. Recent national registry data suggest that donor oocyte recipients have stable rates of pregnancy outcomes before age 45, after which there is a small but steady and significant decline. Copyright © 2014 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Mind the information gap: fertility rate and use of cesarean delivery and tocolytic hospitalizations in Taiwan.

Science.gov (United States)

Ma, Ke-Zong M; Norton, Edward C; Lee, Shoou-Yih D

2011-12-12

Physician-induced demand (PID) is an important theory to test given the longstanding controversy surrounding it. Empirical health economists have been challenged to find natural experiments to test the theory because PID is tantamount to strong income effects. The data requirements are both a strong exogenous change in income and two types of treatment that are substitutes but have different net revenues. The theory implies that an exogenous fall in income would lead physicians to recoup their income by substituting a more expensive treatment for a less expensive treatment. This study takes advantages of the dramatic decline in the Taiwanese fertility rate to examine whether an exogenous and negative income shock to obstetricians and gynecologists (ob/gyns) affected the use of c-sections, which has a higher reimbursement rate than vaginal delivery under Taiwan's National Health Insurance system during the study period, and tocolytic hospitalizations. The primary data were obtained from the 1996 to 2004 National Health Insurance Research Database in Taiwan. We hypothesized that a negative income shock to ob/gyns would cause them to provide more c-sections and tocolytic hospitalizations to less medically-informed pregnant women. Multinomial probit and probit models were estimated and the marginal effects of the interaction term were conducted to estimate the impacts of ob/gyn to birth ratio and the information gap. Our results showed that a decline in fertility did not lead ob/gyns to supply more c-sections to less medically-informed pregnant women, and that during fertility decline ob/gyns may supply more tocolytic hospitalizations to compensate their income loss, regardless of pregnant women's access to health information. The exogenous decline in the Taiwanese fertility rate and the use of detailed medical information and demographic attributes of pregnant women allowed us to avoid the endogeneity problem that threatened the validity of prior research. They also

Demographic upheavals in the former USSR.

Science.gov (United States)

Haub, C

1995-01-01

Fertility and life expectancy have changed since the breakup of the Soviet republics in 1991 and continue to change very rapidly. Before 1991, the USSR was the fastest growing developed country in the world. Annual growth rates in the mid-1980s were 0.9% compared to only 0.1% in Europe or 1.1% in the US. Immigration did not greatly affect the USSR's growth rate. By 1993, the population had declined in 8 of the 15 former republics. Deaths exceeded births in Russia, Belarus, Ukraine, Estonia, and Latvia, followed by Lithuania in 1994. The last census was conducted in 1989. Fertility declined in Russia from 1.9 in 1990 to 1.4 in 1993. Fertility has been low in Lithuania at 1.7, in the Ukraine at 1.6, in Latvia at 1.5, and in Estonia at 1.4. Kazakhstan, Georgia, and Kyrgyzstan have experienced fertility decline, which was affected by emigration to Russia and other countries after 1990. 25 million Russians have resided in the former republics in 1990. In Kazakhstan, the 160,000 more births than deaths were offset by 200,000 emigrants. Central republics with higher fertility experienced declines after 1990; for example, Kyrgyzstan declined from 3.7 in 1990 to 3.3 in 1993. Life expectancy for males in Russia in 1993 was 58.9 years, which was a decline from 63.8 years in 1990. About 50% of the decline in life expectancy was due to circulatory diseases, and about 25% was due to external causes such as accidents, suicide, and alcoholism. Infant mortality has been increasing since 1990; for example, it increased in the Ukraine from 12.9 in 1990 to 14.1 in 1992. Russia's population in 1993 experienced 700,000 more deaths than births. The demographic impact will be declining school enrollments and smaller employment among the working population to support the aged. The change to a market economy has been uneven in Russia, where it has advanced more rapidly than in the republics. It is unclear whether the declining birth rate and increasing mortality rates will continue, but

Adolescent contraceptive use and its effects on fertility

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David Antonio Sánchez-Páez

2018-04-01

Full Text Available Background: Adolescent reproductive health is part of internationally agreed development goals. Unmarried adolescents are not commonly included in global monitoring of contraceptive usedespite the more severe consequences of unintended childbearing for them. Objective: We document levels and trends of contraceptive prevalence and demand for married and sexually active unmarried adolescent women aged 15-19 in Latin America and sub-Saharan Africa. We estimate the effect of adolescent contraceptive use and marital status on fertility and the impact of meeting current demand. Methods: We propose a fertility model informed by the proximate determinants framework separating adolescents by marital status. Linear Mixed Model estimates are based on aggregate data from 120 DHS surveys for 34 developing countries. Results: Increasing contraceptive prevalence has already reduced adolescent fertility by 6.8Š in Latin America and 4.1Š in sub-Saharan Africa. Meeting the total demand for contraceptives of unmarried adolescents would lead to an additional decrease in fertility of 8.9Š and 17.4Š respectively. Conclusions: Contraceptive demand and prevalence are generally higher for sexually active unmarried adolescent women than for those married. Increasing prevalence has already had an impact in declining fertility, but there is a potentially larger effect if high levels of unmet need are eliminated, particularly in sub-Saharan Africa. Such reduction would have a significant impact on adolescent health. Contribution: We provide evidence of the importance of contraceptive use of unmarried sexually active adolescent women in explaining trends in adolescent fertility. We estimate the potential effect of meeting the contraceptive needs of married and unmarried adolescents on unintended childbearing.

The long-term determinants of marital fertility in the developed world (19th and 20th centuries: The role of welfare policies

Directory of Open Access Journals (Sweden)

Jesús Sánchez-Barricarte

2017-04-01

Full Text Available Background: Demographic transition theory was shattered dramatically as a result of the research carried out in the course of the Princeton European Fertility Project. There is still no consensus among demographers as to the causes underlying the fertility transition. Objective: We set out to test the explanatory capacity of certain variables which have traditionally been used to interpret the historical decline in fertility (mortality, level of education, economic development, urbanization as well as the role played by the rise of the welfare state. Methods: We collected information on different kinds of socioeconomic variables in 25 developed countries over a very long period of time. We carried out panel cointegrating regressions and country panel fixed and time effects generalized least squares. Results: We show that the decline in mortality, the increase in educational level, and economic factors all played a leading role in the historical decline in fertility. We found that the present welfare system places a remarkable burden on those who decide to have a family. Conclusions: A new kind of public social transfer model needs to be designed which will minimize the damaging consequences that our current welfare states have had with regard to fertility. Contribution: 1 The emphasis on the causal impact of the emergence and maturation of the social welfare system using Lindert's data on social transfers since the late 19th century to 1990. 2 The enormous amount of historical data compiled, as documented in the Appendix. 3 The modern panel cointegration techniques used to analyze the long- and short-term impacts of the different determinants of fertility.

No evident spatial genetic structuring in the rapidly declining Black-tailed Godwit

NARCIS (Netherlands)

Trimbos, K.B.; Musters, C.J.M.; Verkuil, Y.I.; Kentie, R.; Piersma, T.; De Snoo, G.; Verkuil, Y.I.

2011-01-01

With 40% of the European Black-tailed Godwit population breeding in The Netherlands, this country harbours internationally significant numbers of this species. However, ongoing agricultural intensification has resulted in the fragmentation of the population and drastic population declines since

Isotope technology as applied to studies of soil fertility, nutrient availability and fertilizer use on flooded rice soils

International Nuclear Information System (INIS)

Patnaik, S.; Mohanty, S.K.; Dash, R.N.

1979-01-01

Research is reviewed on soil fertility and nutrient availability in relation to fertilizer efficiency, especially o stimulated the mineralization of soil N. Losses of added N from oxidation, leaching, denitrification and volatilization could be minimized through placement of N fertilizer in the reduced zone or by the addition of rice straw for rapid immobilization of added N. Fe-P and, to some extent, Al-P provided P to the rice plants, particularly in P-deficient soils. Added phosphates were converted to these forms which, under waterlogged soil conditions, released more P into the soil solution through reductive solubilization of Fe-P and hydrolytic dissolution of Al-P. The rice plants generally absorbed fertilizer N during the vegetative growth period and N mineralized from soil organic matter during the reproductive growth period. 15 N studies indicated higher grain yield and utilization of applied N through fractional application of 70-80% during the vegetative growth period, and the remaining 20-30% top-dressed at the panicle initiation stage. Ammonia-containing and -forming (urea) fertilizers were superior to the nitrate form of N. In field tests, however, the crop recovery of applied N was relatively low. Phosphatic fertilizers were best applied at puddling. In general, water-soluble phosphates were superior to citrate-soluble or insoluble phosphates. The latter could be made as efficient as the water-soluble phosphate, at comparable low rates, by applying to the moist aerobic acid soil 2-3 weeks before flooding and transplanting rice. Tracer studies have been used to evaluate the nutrient-supplying capacity of the soil from the 'A' value concept. 'A' values varied with varying conditions of soil, rate, time and form of fertilizer application. Zn nutrition of the rice plant and fertilizer use with 65 Zn have been studied relatively little. Some lines of future work are suggested

Education stalls and subsequent stalls in African fertility: A descriptive overview

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Anne Goujon

2015-12-01

Full Text Available Background: Recent stalls in fertility decline have been observed in a few countries in sub-Saharan Africa, and so far no plausible common reason has been identified in the literature. This paper develops the hypothesis that these fertility stalls could be associated with stalls in the progress of education among the women of the relevant cohorts, possibly resulting partly from the Structural Adjustment Programs (SAPs of the 1980s. Methods: We descriptively link the change in the education composition of successive cohorts of young women in sub-Saharan Africa and the recent fertility stalls. We use reconstructed data on population by age, gender, and level of education from www.wittgenstein centre.org/dataexplorer, and fertility rates from the United Nations. Results: In most sub-Saharan African countries, we observe that the same countries that had fertility stalls had a stall in the progress of education, particularly for young women who were of primary school age during the 1980s, when most of the countries were under structural adjustment. Conversely, stalls in fertility are less common in countries that did not have an education stall, possibly in relation to SAPs. Conclusions: The results point to the possibility of a link between the recent fertility stalls and discontinuities in the improvement of the education of the relevant cohorts, which in turn could be related to the SAPs in the 1980s. This descriptive finding now needs to be corroborated through more detailed cohort-specific fertility analysis. If the education-fertility link can be further established, it will have important implications for the projections of population growth in affected countries.

Causes of maternal mortality decline in Matlab, Bangladesh.

Science.gov (United States)

Chowdhury, Mahbub Elahi; Ahmed, Anisuddin; Kalim, Nahid; Koblinsky, Marge

2009-04-01

Bangladesh is distinct among developing countries in achieving a low maternal mortality ratio (MMR) of 322 per 100,000 livebirths despite the very low use of skilled care at delivery (13% nationally). This variation has also been observed in Matlab, a rural area in Bangladesh, where longitudinal data on maternal mortality are available since the mid-1970s. The current study investigated the possible causes of the maternal mortality decline in Matlab. The study analyzed 769 maternal deaths and 215,779 pregnancy records from the Health and Demographic Surveillance System (HDSS) and other sources of safe motherhood data in the ICDDR,B and government service areas in Matlab during 1976-2005. The major interventions that took place in both the areas since the early 1980s were the family-planning programme plus safe menstrual regulation services and safe motherhood interventions (midwives for normal delivery in the ICDDR,B service area from the late 1980s and equal access to comprehensive emergency obstetric care [EmOC] in public facilities for women from both the areas). National programmes for social development and empowerment of women through education and microcredit programmes were implemented in both the areas. The quantitative findings were supplemented by a qualitative study by interviewing local community care providers for their change in practices for maternal healthcare over time. After the introduction of the safe motherhood programme, reduction in maternal mortality was higher in the ICDDR,B service area (68.6%) than in the government service area (50.4%) during 1986-1989 and 2001-2005. Reduction in the number of maternal deaths due to the fertility decline was higher in the government service area (30%) than in the ICDDR,B service area (23%) during 1979-2005. In each area, there has been substantial reduction in abortion-related mortality--86.7% and 78.3%--in the ICDDR,B and government service areas respectively. Education of women was a strong predictor

Mortality-fertility synergies during the demographic transition in the developed world.

Science.gov (United States)

Sánchez-Barricarte, Jesús J

2017-07-01

The classic theory used to explain the demographic transition assumes that mortality is the key explanatory variable influencing the decline in fertility. However, the empirical results obtained in what is known as the Princeton European Fertility Project have led many specialists to question this assumption. Using both national and provincial aggregated data for 25 countries over a long time span, the analysis reported in this paper found that mortality does indeed play a fundamental role in accounting for the main demographic changes that occurred both before and during the transitional period. Others' research based on individual data has shown clearly that the number of surviving children was indeed an important factor for reproductive decisions. My analysis, using aggregated data, reached largely similar conclusions regarding the role of mortality in changing reproductive trends, via its impact on nuptiality and marital fertility at different stages of the demographic transition.

Evaluation of soil and foliar fertilization on wheat yield and quality

International Nuclear Information System (INIS)

Ndiema, A.C.; Maina, M.P.D.; Kamundia, W.J.

2001-01-01

Traditionally wheat farmers in Kenya apply basal compound fertilizer like diammonium phosphate (DAP), Triple super phosphate (TSP). Plants require a considerable number of different elements for optimal growth. One way of supplying these micronutrients is through foliar fertilization. However there was an increase of 71.7% for 40kg N/ha plus bayfolan in Njoro over the control, 61.8% for bayfolan alone a foliar fertilizer, which contain a wide range of plant nutrients. In Molo the control out-yielded all the treatments indicating that planting the crop with DAP is sufficient. Foliar fertilizer was applied directly to the plant leaves to enhance crop yield due to their rapid absorption. The potential of improving yields comes as a result of increase in number of seeds. The objective of this study was to evaluate the effects of foliar fertilizer on wheat yield when used alone or in combination with soil-applied fertilizers. Byfolan is a fast acting fertilizer with nutrients rapidly becoming available to the plant. The composition of Bayfolan includes N (11%), P (8%), K (6%), Fe (0.019%), Mn (0.016%). Zn (0.0061% ), Co (0.00035%), Mo (0.00009%), sodium, sulphur, vitamin B 1 and growth hormones. The design was RCBD with nine (9) treatments and three (3) replications. The treatments included control, 20kg N/ha, 40kg N/ha, 80kg N/ha, Bayfolan foliar, 20kg N/ha + Baylon a foliar, 40kg N/ha + Bayfolan foliar, 20kg N/ha urea in solution form, 20kg N/ha urea in solution form + Bayfolan foliar. DAP was applied at the rate of 130kg/ha, as a blanket treatment at planting timeto provide N and P for initial growth. Significant difference in spike density and kernel weight at 5% level was observed at farms in Njoro but not at farms in Molo. (author)

Severe exacerbations and decline in lung function in asthma

DEFF Research Database (Denmark)

O'Byrne, Paul M; Pedersen, Søren; Lamm, Carl Johan

2009-01-01

RATIONALE: To evaluate the association between asthma exacerbations and the decline in lung function, as well as the potential effects of an inhaled corticosteroid, budesonide, on exacerbation-related decline in patients with asthma. OBJECTIVES: To determine whether severe asthma exacerbations...... with low-dose inhaled budesonide prevents severe asthma-related events (exacerbations requiring hospitalization or emergency treatment) and decline in lung function. MEASUREMENTS AND MAIN RESULTS: There were 315 patients who experienced at least one severe asthma exacerbation, of which 305 were analyzable...... of reduction afforded by budesonide, in patients who experienced at least one severe asthma-related event compared with those who did not, was statistically significant (P = 0.042). CONCLUSIONS: Severe asthma exacerbations are associated with a more rapid decline in lung function. Treatment with low doses...

The decline and fall of Type II error rates

Science.gov (United States)

Steve Verrill; Mark Durst

2005-01-01

For general linear models with normally distributed random errors, the probability of a Type II error decreases exponentially as a function of sample size. This potentially rapid decline reemphasizes the importance of performing power calculations.

The Expression of TALEN before Fertilization Provides a Rapid Knock-Out Phenotype in Xenopus laevis Founder Embryos.

Science.gov (United States)

Miyamoto, Kei; Suzuki, Ken-Ichi T; Suzuki, Miyuki; Sakane, Yuto; Sakuma, Tetsushi; Herberg, Sarah; Simeone, Angela; Simpson, David; Jullien, Jerome; Yamamoto, Takashi; Gurdon, J B

2015-01-01

Recent advances in genome editing using programmable nucleases have revolutionized gene targeting in various organisms. Successful gene knock-out has been shown in Xenopus, a widely used model organism, although a system enabling less mosaic knock-out in founder embryos (F0) needs to be explored in order to judge phenotypes in the F0 generation. Here, we injected modified highly active transcription activator-like effector nuclease (TALEN) mRNA to oocytes at the germinal vesicle (GV) stage, followed by in vitro maturation and intracytoplasmic sperm injection, to achieve a full knock-out in F0 embryos. Unlike conventional injection methods to fertilized embryos, the injection of TALEN mRNA into GV oocytes allows expression of nucleases before fertilization, enabling them to work from an earlier stage. Using this procedure, most of developed embryos showed full knock-out phenotypes of the pigmentation gene tyrosinase and/or embryonic lethal gene pax6 in the founder generation. In addition, our method permitted a large 1 kb deletion. Thus, we describe nearly complete gene knock-out phenotypes in Xenopus laevis F0 embryos. The presented method will help to accelerate the production of knock-out frogs since we can bypass an extra generation of about 1 year in Xenopus laevis. Meantime, our method provides a unique opportunity to rapidly test the developmental effects of disrupting those genes that do not permit growth to an adult able to reproduce. In addition, the protocol shown here is considerably less invasive than the previously used host transfer since our protocol does not require surgery. The experimental scheme presented is potentially applicable to other organisms such as mammals and fish to resolve common issues of mosaicism in founders.

Fertility decline and gender preference--an experience of Kerala.

Science.gov (United States)

Ramakumar, R; Devi, K S

1989-12-01

Using data from 1980 Fertility Survey from Kerala, India, researchers analyzed responses from 2242 women to ascertain if gender preference existed. Acceptance of contraception differed among the 3 districts from 70.33% in Ernakulam, 68.05% in Alleppey, and 24.45% in Palghat. The acceptance rate was higher among women who had only 1 son than among those who had only 1 daughter. Further, the rate for women in Palghat with only 1 son (13.12) was almost 2 times higher than that of those with only 1 daughter (6.9). The extent of son preference was lowest in Alleppey. Generally, couples who had the preferred number of sons were more likely to choose sterilization as their method of birth control while those who continued to have daughters without the desired number of sons chose nonterminal methods. The differences between the averages of sons and daughters in terms of total family size are not very wide, however, therefore the degree of son preference has not greatly changed either family size or its composition, especially in Alleppey and Ernakulam. Even though son preference is generally strong among Hindus, the Hindus in both Alleppey and Ernakulam do not demonstrate a strong preference for sons index. On the other hand, the Hindus in Palghat are quite conservative and do demonstrate a high son preference index. Mothers who have attended a formal school for at least 5 years show little discrimination against a daughter. Ernakulam has reached the stage in the transition from a noncontracepting society to a contracepting society when the number of children of the same sex outnumber the other, couples decide to have no more children to maintain small size norms. In Alleppey, the deisre for small size families was the primary consideration for contraceptive use and son preference was secondary.

Rapid warming accelerates tree growth decline in semi-arid forests of Inner Asia.

Science.gov (United States)

Liu, Hongyan; Park Williams, A; Allen, Craig D; Guo, Dali; Wu, Xiuchen; Anenkhonov, Oleg A; Liang, Eryuan; Sandanov, Denis V; Yin, Yi; Qi, Zhaohuan; Badmaeva, Natalya K

2013-08-01

Forests around the world are subject to risk of high rates of tree growth decline and increased tree mortality from combinations of climate warming and drought, notably in semi-arid settings. Here, we assess how climate warming has affected tree growth in one of the world's most extensive zones of semi-arid forests, in Inner Asia, a region where lack of data limits our understanding of how climate change may impact forests. We show that pervasive tree growth declines since 1994 in Inner Asia have been confined to semi-arid forests, where growing season water stress has been rising due to warming-induced increases in atmospheric moisture demand. A causal link between increasing drought and declining growth at semi-arid sites is corroborated by correlation analyses comparing annual climate data to records of tree-ring widths. These ring-width records tend to be substantially more sensitive to drought variability at semi-arid sites than at semi-humid sites. Fire occurrence and insect/pathogen attacks have increased in tandem with the most recent (2007-2009) documented episode of tree mortality. If warming in Inner Asia continues, further increases in forest stress and tree mortality could be expected, potentially driving the eventual regional loss of current semi-arid forests. © 2013 John Wiley & Sons Ltd.

Regional differences in decline of mortality from selected conditions: The Netherlands, 1969-1984

NARCIS (Netherlands)

Mackenbach, J. P.; Looman, C. W.; Kunst, A. E.; Habbema, J. D.; van der Maas, P. J.

1988-01-01

In The Netherlands, as in many other industrialized countries, recent mortality developments have been characterized by rapid declines for a number of important causes of death. The results of an analysis of regional variation in mortality decline within The Netherlands are reported, covering the

Diversity and Enzyme Activity of Ectomycorrhizal Fungal Communities Following Nitrogen Fertilization in an Urban-Adjacent Pine Plantation

Directory of Open Access Journals (Sweden)

Chen Ning

2018-02-01

Full Text Available Rapid economic development and accelerated urbanization in China has resulted in widespread atmospheric nitrogen (N deposition. One consequence of N deposition is the alteration of mycorrhizal symbioses that are critical for plant resource acquisition (nitrogen, N, phosphorus, P, water. In this study, we characterized the diversity, composition, and functioning of ectomycorrhizal (ECM fungal communities in an urban-adjacent Pinus elliottii plantation under ambient N deposition (~24 kg N ha−1 year−1, and following N fertilization (low N, 50 kg N ha−1 year−1; high N, 300 kg N ha−1 year−1. ECM functioning was expressed as the potential activities of extracellular enzymes required for organic N (protease, P (phosphomonoesterase, and recalcitrant polymers (phenol oxidase. Despite high ambient N deposition, ECM community composition shifted under experimental N fertilization, and those changes were linked to disparate levels of soil minerals (P, K and organic matter (but not N, a decline in acid phosphatase (AP, and an increase in phenol oxidase (PO potential activities. Based on enzyme stoichiometry, medium-smooth exploration type ECM species invested more in C acquisition (PO relative to P (AP following high N fertilization than other exploration types. ECM species with hydrophilic mantles also showed higher enzymatic PO:AP ratios than taxa with hydrophobic mantles. Our findings add to the accumulating evidence that shifts in ECM community composition and taxa specialized in organic C, N, and P degradation could modulate the soil nutrient cycling in forests exposed to chronic elevated N input.

Fertility in women of late reproductive age: the role of serum anti-Müllerian hormone (AMH) levels in its assessment.

Science.gov (United States)

Meczekalski, B; Czyzyk, A; Kunicki, M; Podfigurna-Stopa, A; Plociennik, L; Jakiel, G; Maciejewska-Jeske, M; Lukaszuk, K

2016-11-01

Fertility is referred to the capability for having offspring and can be evaluated by fertility rate. Women's fertility is strictly dependent on individual's age. The fertility peak occurs in the early 20s, and it starts to decline in the third and fourth decades of life (falling sharply after age 35). The aim of this work is to review the available data concerning fertility in women of late reproductive age, especially the role of serum anti-Müllerian hormone (AMH) levels. There are a lot of factors responsible for decrease of fertility in women of late reproductive age. These factors can be classified as oocyte-dependent (decrease in oocyte quantity and quality) and oocyte-independent (reproductive organs [uterus, oviducts] status and general health). Anti-Müllerian hormone (AMH) is a dimeric glycoprotein of the transforming growth factor-β (TGF-β) superfamily produced directly by the ovarian granulosa cells of secondary, preantral, and early antral follicles. It has been used as an ovarian reserve marker since 2002. Anti-Müllerian hormone seems to be the best endocrine marker for assessing the age-related decline of the ovarian pool in healthy women. Evaluation of AMH's predictive value in the naturally aging population is important for counseling women about reproductive planning as well as for treatment planning for women experiencing hormone-sensitive gynecological conditions such as endometriosis and fibroids. AMH can be considered as an indicator of fertility in late reproductive age women and pregnancy outcome in assisted reproductive technology cycles. AMH can strongly predict poor response in the controlled ovarian stimulation.

Conception intervals and the substitution of fertility over time.

Science.gov (United States)

Olsen, R J; Farkas, G

1985-04-01

This paper applies the waiting-time regression methods of Olsen and Wolpin (1983) to an analysis of fertility. A utility maximizing model is set up and used to provide some guidance for an empirical analysis. The data are from an experimental guaranteed job program, the Youth Incentive Entitlement Pilot Project, aimed at young women 16 to 20 years old, from poverty-level families, and not yet high school graduates. The waiting-time regression method of estimation permits the youth in question to be used as her own control revealing how eligibility for the jobs program changes the durations of periods between live-birth conceptions. 3890 women surveyed had 1 birth, 429 had 2, 112 had 3, 26 had 4, and 7 had 5. Without this person specific control described here, the most important factors affecting fertility are number of siblings (negative effect), labor market attachment by parents, especially the father, and the presence of the natural father. With the person specific control, the results predicted from economic theory do emerge: even adolescent and young women consider the economic consequences of fertility reflected in effects of fertility when wages are high in favor of fertility with lower wages. Post program effects (taking place after youths lose eligibility for the program) are a rather rapid making up for foregone fertility, reducing likelihood of net reductions of total fertility.

Lion (Panthera leo) populations are declining rapidly across Africa, except in intensively managed areas.

Science.gov (United States)

Bauer, Hans; Chapron, Guillaume; Nowell, Kristin; Henschel, Philipp; Funston, Paul; Hunter, Luke T B; Macdonald, David W; Packer, Craig

2015-12-01

We compiled all credible repeated lion surveys and present time series data for 47 lion (Panthera leo) populations. We used a Bayesian state space model to estimate growth rate-λ for each population and summed these into three regional sets to provide conservation-relevant estimates of trends since 1990. We found a striking geographical pattern: African lion populations are declining everywhere, except in four southern countries (Botswana, Namibia, South Africa, and Zimbabwe). Population models indicate a 67% chance that lions in West and Central Africa decline by one-half, while estimating a 37% chance that lions in East Africa also decline by one-half over two decades. We recommend separate regional assessments of the lion in the World Conservation Union (IUCN) Red List of Threatened Species: already recognized as critically endangered in West Africa, our analysis supports listing as regionally endangered in Central and East Africa and least concern in southern Africa. Almost all lion populations that historically exceeded ∼ 500 individuals are declining, but lion conservation is successful in southern Africa, in part because of the proliferation of reintroduced lions in small, fenced, intensively managed, and funded reserves. If management budgets for wild lands cannot keep pace with mounting levels of threat, the species may rely increasingly on these southern African areas and may no longer be a flagship species of the once vast natural ecosystems across the rest of the continent.

Assessing the removal of organic micro-pollutants from anaerobic membrane bioreactor effluent by fertilizer-drawn forward osmosis

KAUST Repository

Kim, Youngjin; Li, Sheng; Chekli, Laura; Woo, Yun Chul; Wei, Chunhai; Phuntsho, Sherub; Ghaffour, NorEddine; Leiknes, TorOve; Shon, Ho Kyong

2017-01-01

In this study, the behavior of organic micro-pollutants (OMPs) transport including membrane fouling was assessed in fertilizer-drawn forward osmosis (FDFO) during treatment of the anaerobic membrane bioreactor (AnMBR) effluent. The flux decline

The influence of rural-urban migration on migrant's fertility behavior in Cameroon.

Science.gov (United States)

Lee, B S

1992-01-01

eventually fertility will decline as economic development continues and women's educational levels increase. Stability in marriages will increase women's confidence needed to control fertility and contribute to the increased use of contraceptives.

Rapid decline in 51Cr-EDTA measured renal function during the first weeks following lung transplantation

DEFF Research Database (Denmark)

Hornum, M.; Iversen, M.; Steffensen, I.

2009-01-01

We previously described a 54% decline in renal function at 6 months after lung transplantation (LTx). We hypothesized that this decline is a very early event following LTx. Thirty-one consecutive patients (16 females/15 males), mean age 49 (+/-13) years, with emphysema, cystic fibrosis/bronchiect......We previously described a 54% decline in renal function at 6 months after lung transplantation (LTx). We hypothesized that this decline is a very early event following LTx. Thirty-one consecutive patients (16 females/15 males), mean age 49 (+/-13) years, with emphysema, cystic fibrosis....../bronchiectasis or idiopathic pulmonary fibrosis were included in an analysis of renal function before and after LTx. The glomerular filtration rate (GFR) was measured using the (51)Cr-ethylenediaminetetra acetic acid plasma clearance single injection technique (mGFR) at baseline before transplantation and at 1, 2, 3 and 12...

Lower leptin/adiponectin ratio and risk of rapid lung function decline in chronic obstructive pulmonary disease

DEFF Research Database (Denmark)

Suzuki, Masaru; Makita, Hironi; Östling, Jörgen

2014-01-01

, and single ELISAs were used to confirm the results. MEASUREMENTS AND MAIN RESULTS: Higher plasma adiponectin levels and a lower leptin/adiponectin ratio at enrollment were significantly associated with an annual decline in FEV1 even after controlling for age, sex, height, and body mass index in the Hokkaido...... COPD cohort study (P = 0.003, P = 0.004, respectively). A lower plasma leptin/adiponectin ratio was also significantly associated with an annual decline in FEV1 in subjects with airflow limitation in the CBQ study (P = 0.014), the patients of which had largely different clinical characteristics...... compared with the Hokkaido COPD cohort study. There were no significant associations between lung function decline and adipokine levels in subjects without airflow limitation. CONCLUSIONS: A lower leptin/adiponectin ratio was associated with lung function decline in patients with COPD in two independent...

Current status of fertility control methods in India

Indian Academy of Sciences (India)

Use of the condom increased to 3.1% from 2.4%. ... Current efforts in India to develop a male contraceptive are mainly directed towards ... the existing range of contraceptive methods available in the National Family Planning Programme. ... long acting, relatively easily removed and fertility returns rapidly after their removal.

Development of a rapid and efficient microinjection technique for gene insertion into fertilized salmonid eggs

Energy Technology Data Exchange (ETDEWEB)

Chandler, D.P.; Welt, M.; Leung, F.C.

1990-10-01

An efficient one-step injection technique for gene insertion into fertilized rainbow trout (Oncorhynchus mykiss) eggs is described, and basic parameters affecting egg survival are reported. Freshly fertilized rainbow trout eggs were injected in the perivitelline space with a recombinant mouse metallothionein-genomic bovine growth hormone (bGH) DNA construct using a 30-gauge hypodermic needle and a standard microinjection system. Relative to control, site of injection and DNA concentration did not affect the egg survival, but injections later than 3--4 hours post fertilization were detrimental. The injection technique permitted treatment of 100 eggs/hr with survivals up to 100%, resulting in a 4% DNA uptake rate as indicated by DNA dot blot analysis. Positive dot blot results also indicated that the injected DNA is able to cross the vitelline membrane and persist for 50--60 days post hatching, obviating the need for direct injection into the germinal disk. Results are consistent with previous transgenic fish work, underscoring the usefulness of the technique for generating transgenic trout and salmonids. 24 refs., 6 figs., 3 tabs.

70-79 Effects of Crop Rotation and NP Fertilizer Rate on Grain Yield a

African Journals Online (AJOL)

Primary nutrient (N, P and K) composition of the ... Crop rotation with fertilizer amendment improved the pH of the soil. Crop rotation and ..... Soil organic carbon contents declined regardless of inputs application for continuously cultivated land (Kapkiyai, 1996). Higher. Organic carbon content next to before planting (1.98 %).

Large cross-sectional study of presbycusis reveals rapid progressive decline in auditory temporal acuity.

Science.gov (United States)

Ozmeral, Erol J; Eddins, Ann C; Frisina, D Robert; Eddins, David A

2016-07-01

The auditory system relies on extraordinarily precise timing cues for the accurate perception of speech, music, and object identification. Epidemiological research has documented the age-related progressive decline in hearing sensitivity that is known to be a major health concern for the elderly. Although smaller investigations indicate that auditory temporal processing also declines with age, such measures have not been included in larger studies. Temporal gap detection thresholds (TGDTs; an index of auditory temporal resolution) measured in 1071 listeners (aged 18-98 years) were shown to decline at a minimum rate of 1.05 ms (15%) per decade. Age was a significant predictor of TGDT when controlling for audibility (partial correlation) and when restricting analyses to persons with normal-hearing sensitivity (n = 434). The TGDTs were significantly better for males (3.5 ms; 51%) than females when averaged across the life span. These results highlight the need for indices of temporal processing in diagnostics, as treatment targets, and as factors in models of aging. Copyright © 2016 Elsevier Inc. All rights reserved.

Time costs, aspirations and the effect of economic growth on German fertility.

Science.gov (United States)

Ermisch, J F

1980-01-01

Recent research has shown strong support for the model of reproductive behavior derived from the new home economics, and it is shown in this discussion that the evidence from the Federal Republic of Germany is consistent with the new home economics model. There is little support for Easterlin's relative economic hypothesis, but there is limited endorsement for model which adds the influence of experience based material aspirations to the new home economics model. Easterlin's relative income model is reviewed before directing attention to the new home economics model and an explanation of fertility movements in West Germany. The new home economics model focuses on the family division of labor between home activities and work outside the home. The marked decline in German fertility during the 1970s is mostly attributable to factors such as expanding women's earning capacities which increased the importance of 2 earner families, who have a different family division of labor and possibly preferences biased towards "quality" of children rather than numbers. Also, real wage growth lagged behind the growth in experience based aspirations, and this drop in relative income is more dramatic if it is presumed that material aspirations are based upon the family's income experienced by a young adult during his/her adolescence, rather than just the father's earnings. The mother's contribution to family income will contribute to her family's actual standard of living and the desired standard of living of her children. The labor force participation rates of married, middle-aged German women increased markedly during the 1st half of the 1950s, thus tending to enhance the increase in the standard of living desired by the young adults reaching marrying and childbearing ages in the mid-1960s. The analysis indicates that if there is not a substantial reduction in the proportion of young married women in the labor force, fertility will move countercyclically. In that there must be some

Fertility awareness and attitudes towards parenthood among Danish university college students.

Science.gov (United States)

Sørensen, Nina Olsén; Marcussen, Signe; Backhausen, Mette Grønbæk; Juhl, Mette; Schmidt, Lone; Tydén, Tanja; Hegaard, Hanne Kristine

2016-12-13

Postponing parenthood has steadily increased during the past decades in Western countries. This trend has affected the size of families in the direction of fewer children born per couple. In addition, higher maternal age is associated with an increased risk of pregnancy-related complications such as prematurity and foetal death, while higher paternal age increases the risk of miscarriage and affects time-to-pregnancy. Hence, understanding the circumstances and reflections that influence the decision is greatly needed and little is known about potential gender difference influencing the choice. The aim was to investigate attitudes towards parenthood, intentions for childbirth and knowledge about fertility issues among men and women. We conducted a cross-sectional study based on a validated 49-item questionnaire among students, who attended selected mandatory lectures at a Danish university college in February to April 2016. The participation rate was 99%, and 517 completed the questionnaire. Though the majority of all participants wished to have children in the future (>86%), there was significant difference between the genders (p = 0.002). Women rated having children to be more important than men did (p fertility issues was similar between genders including poor knowledge about the age-related decline in female fertility. While women found it more important to have children before being 'too old' (p = 0.04), still more than 40% of all respondents intended to have their last child after the age of 35 years. For both genders the most important prerequisite for parenthood was having a partner to share responsibility with. Perceived or experienced life changes related to parenthood were generally positive such as personal development. The majority of respondents wished to have children, but many desired to have these after the biological decline in female fertility. The moderate knowledge level among both genders uncovered in this study is of concern. Future

The long-term effects of acute exposure to ionising radiation on survival and fertility in Daphnia magna

International Nuclear Information System (INIS)

Sarapultseva, Elena I.; Dubrova, Yuri E.

2016-01-01

The results of recent studies have provided strong evidence for the transgenerational effects of parental exposure to ionising radiation and chemical mutagens. However, the transgenerational effects of parental exposure on survival and fertility remain poorly understood. To establish whether parental irradiation can affect the survival and fertility of directly exposed organisms and their offspring, crustacean Daphnia magna were given 10, 100, 1000 and 10,000 mGy of acute γ-rays. Exposure to 1000 and 10,000 mGy significantly compromised the viability of irradiated Daphnia and their first-generation progeny, but did not affect the second-generation progeny. The fertility of F 0 and F 1 Daphnia gradually declined with the dose of parental exposure and significantly decreased at dose of 100 mGy and at higher doses. The effects of parental irradiation on the number of broods were only observed among the F 0 Daphnia exposed to 1000 and 10,000 mGy, whereas the brood size was equally affected in the two consecutive generations. In contrast, the F 2 total fertility was compromised only among progeny of parents that received the highest dose of 10,000 mGy. We propose that the decreased fertility observed among the F 2 progeny of parents exposed to 10,000 mGy is attributed to transgenerational effects of parental irradiation. Our results also indicate a substantial recovery of the F 2 progeny of irradiated F 0 Daphnia exposed to the lower doses of acute γ-rays. - Highlights: • Viability of irradiated daphnids and their F 1 progeny is compromised. • Viability of the F 2 progeny of irradiated parents is not affected. • Total fertility of irradiated daphnids and their F 1 progeny declines with the dose. • Total fertility of the F 2 progeny of parents exposed to 10,000 mGy is compromised. • The decreased fertility among the F 2 progeny is transgenerational phenomenon.

The long-term effects of acute exposure to ionising radiation on survival and fertility in Daphnia magna

Energy Technology Data Exchange (ETDEWEB)

Sarapultseva, Elena I. [Department of Biology, Institute of Nuclear Power Engineering NRNU MEPhI, Studgorodok,1, Obninsk, Kaluga Region 249040 (Russian Federation); National Research Nuclear University “MEPhI”, Kashirskoe Highway, 31, Moscow 115409 (Russian Federation); Dubrova, Yuri E., E-mail: yed2@le.ac.uk [Department of Genetics, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Vavilov Institute of General Genetics, Russian Academy of Sciences, Gubkina Str. 3, 11933 Moscow (Russian Federation)

2016-10-15

The results of recent studies have provided strong evidence for the transgenerational effects of parental exposure to ionising radiation and chemical mutagens. However, the transgenerational effects of parental exposure on survival and fertility remain poorly understood. To establish whether parental irradiation can affect the survival and fertility of directly exposed organisms and their offspring, crustacean Daphnia magna were given 10, 100, 1000 and 10,000 mGy of acute γ-rays. Exposure to 1000 and 10,000 mGy significantly compromised the viability of irradiated Daphnia and their first-generation progeny, but did not affect the second-generation progeny. The fertility of F{sub 0} and F{sub 1}Daphnia gradually declined with the dose of parental exposure and significantly decreased at dose of 100 mGy and at higher doses. The effects of parental irradiation on the number of broods were only observed among the F{sub 0}Daphnia exposed to 1000 and 10,000 mGy, whereas the brood size was equally affected in the two consecutive generations. In contrast, the F{sub 2} total fertility was compromised only among progeny of parents that received the highest dose of 10,000 mGy. We propose that the decreased fertility observed among the F{sub 2} progeny of parents exposed to 10,000 mGy is attributed to transgenerational effects of parental irradiation. Our results also indicate a substantial recovery of the F{sub 2} progeny of irradiated F{sub 0}Daphnia exposed to the lower doses of acute γ-rays. - Highlights: • Viability of irradiated daphnids and their F{sub 1} progeny is compromised. • Viability of the F{sub 2} progeny of irradiated parents is not affected. • Total fertility of irradiated daphnids and their F{sub 1} progeny declines with the dose. • Total fertility of the F{sub 2} progeny of parents exposed to 10,000 mGy is compromised. • The decreased fertility among the F{sub 2} progeny is transgenerational phenomenon.

Feasibility of surveillance of changes in human fertility and semen quality.

Science.gov (United States)

Stewart, T M; Brown, E H; Venn, A; Mbizvo, M T; Farley, T M; Garrett, C; Baker, H W

2001-01-01

There is concern that male fertility is declining, but this is difficult to study because few men volunteer for studies of semen quality, and recruitment bias may over-represent the subfertile. The Human Reproduction Programme of the World Health Organization developed a protocol for multicentre studies of fertility involving a questionnaire for pregnant women to obtain time to pregnancy (TTP): the number of menstrual cycles taken to conceive. Male characteristics and semen quality will be determined in a subset of the partners. Our aim was to validate the TTP questionnaire, and to examine potential recruitment bias and feasibility of conducting large-scale surveillance of fertility. The questionnaire was administered to 120 pregnant women (16-32 weeks). Validation included internal reliability by consistency of responses, test-re-test reliability by repeat administration (20 women) and accuracy by comparison of gestational age from first antenatal ultrasound and menstrual dates. Internal reliability was high. Agreement between categorical responses on re-testing was very good (k > 0.8). In both the re-test and gestational age analysis, differences in TTP of 1 cycle were found (standard deviation recruitment bias. Response rates indicate the feasibility of surveillance of fertility in large maternity centres.

No detectable fertility benefit from a single additional mating in wild stalk-eyed flies.

Directory of Open Access Journals (Sweden)

Elisabeth Harley

2010-12-01

Full Text Available Multiple mating by female insects is widespread, and the explanation(s for repeated mating by females has been the subject of much discussion. Females may profit from mating multiply through direct material benefits that increase their own reproductive output, or indirect genetic benefits that increase offspring fitness. One particular direct benefit that has attracted significant attention is that of fertility assurance, as females often need to mate multiply to achieve high fertility. This hypothesis has never been tested in a wild insect population.Female Malaysian stalk-eyed flies (Teleopsis dalmanni mate repeatedly during their lifetime, and have been shown to be sperm limited under both laboratory and field conditions. Here we ask whether receiving an additional mating alleviates sperm limitation in wild females. In our experiment one group of females received a single additional mating, while a control group received an interrupted, and therefore unsuccessful, mating. Females that received an additional mating did not lay more fertilised eggs in total, nor did they lay proportionately more fertilised eggs. Female fertility declined significantly through time, demonstrating that females were sperm limited. However, receipt of an additional mating did not significantly alter the rate of this decline.Our data suggest that the fertility consequences of a single additional mating were small. We discuss this effect (or lack thereof, and suggest that it is likely to be attributed to small ejaculate size, a high proportion of failed copulations, and the presence of X-linked meiotic drive in this species.

Rapid response of arbuscular mycorrhizal fungal communities to short-term fertilization in an alpine grassland on the Qinghai-Tibet Plateau

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Xingjia Xiang

2016-07-01

Full Text Available Background: The Qinghai-Tibet Plateau (QTP is home to the vast grassland in China. The QTP grassland ecosystem has been seriously degraded by human land use practices and climate change. Fertilization is used in this region to increase vegetation yields for grazers. The impact of long-term fertilization on plant and microbial communities has been studied extensively. However, the influence of short-term fertilization on arbuscular mycorrhizal fungal (AMF communities in the QTP is largely unknown, despite their important functional role in grassland ecosystems. Methods: We investigated AMF community responses to three years of N and/or P addition at an experimental field site on the QTP, using the Illumina MiSeq platform (PE 300. Results: Fertilization resulted in a dramatic shift in AMF community composition and NP addition significantly increased AMF species richness and phylogenetic diversity. Aboveground biomass, available phosphorus, and NO3− were significantly correlated with changes in AMF community structure. Changes in these factors were driven by fertilization treatments. Thus, fertilization had a large impact on AMF communities, mediated by changes in aboveground productivity and soil chemistry. Discussion: Prior work has shown how plants often lower their reliance on AMF symbioses following fertilization, leading to decrease AMF abundance and diversity. However, our study reports a rise in AMF diversity with fertilization treatment. Because AMF can provide stress tolerance to their hosts, we suggest that extreme weather on the QTP may help drive a positive relationship between fertilizer amendment and AMF diversity.

Fertility counseling and preservation practices in youth with lupus and vasculitis undergoing gonadotoxic therapy.

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Nahata, Leena; Sivaraman, Vidya; Quinn, Gwendolyn P

2016-11-01

To assess fertility counseling and preservation practices among children, adolescents, and young adults with rheumatic diseases undergoing cyclophosphamide (CTX) treatment. Retrospective chart review (2006-2016). Academic pediatric center. Male and female patients with systemic lupus erythematosus, Wegener's granulomatosis/granulomatosis with polyangiitis, or other vaculitides, receiving CTX treatment. None. Documentation of fertility counseling and fertility preservation. A total of 58 subjects met the inclusion criteria; 5 were excluded due to incomplete records, thus N = 53. Of these 75% were female (N = 40). Median age was 14 years at diagnosis and 15 years at first CTX treatment. A total of 51% of subjects (69% of males and 45% of females) had no documentation about potential fertility loss before CTX treatment. Among females where fertility counseling was documented, the only fertility preservation option discussed was leuprolide acetate (LA), which was pursued in all of these cases. Of 13 males (77% postpubertal), 3 were offered sperm banking, of whom 2 declined and the other attempted after treatment began and was azoospermic. Of 53 patients, 1 was referred to a fertility specialist. Mean cumulative CTX dose was 9.2 g in males and 8 g in females. Based on these findings, increasing awareness about infertility risk, fertility preservation options, and referral to fertility specialists is needed among pediatric rheumatologists. Prospective studies are needed to assess fertility outcomes in this patient population (including effectiveness of LA with regard to pregnancy rates [PRs]), as well as barriers/facilitators to fertility counseling and fertility preservation. Copyright © 2016 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Demographic Disequilibrium in Early Twentieth Century Thailand: Falling Mortality, Rising Fertility, or Both?

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Carmichael, Gordon A

2008-07-17

Estimates of Thai crude birth and death rates date from 1920 when the former was around 20 per thousand higher than the latter, implying natural increase of 2 percent per annum. Such disequilibrium cannot have been the norm over the long term historical past, when population growth must have been comparatively slow. This paper explores the bases for likely past relative equilibrium between Siamese birth and death rates, then seeks to explain the disequilibrium apparent by 1920. Classic demographic transition theory postulates initially high birth and death rates, this equilibrium eventually being broken by falling mortality. In Thailand, however, there is likely to have been both significant mortality decline and appreciable fertility increase after 1850, as the virtual elimination of indigenous warfare, rapid growth of the export rice economy and the demise of slavery and corvée labour created a new domestic environment. Characterized by more dispersed, often frontier, settlement, this environment was unprecedentedly sedate and settled, afforded ordinary households a previously unknown level of control over their resources of labour, and generated optimism about prospects for the next generation.

Maternal risk of breeding failure remained low throughout the demographic transitions in fertility and age at first reproduction in Finland.

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Jianghua Liu

Full Text Available Radical declines in fertility and postponement of first reproduction during the recent human demographic transitions have posed a challenge to interpreting human behaviour in evolutionary terms. This challenge has stemmed from insufficient evolutionary insight into individual reproductive decision-making and the rarity of datasets recording individual long-term reproductive success throughout the transitions. We use such data from about 2,000 Finnish mothers (first births: 1880s to 1970s to show that changes in the maternal risk of breeding failure (no offspring raised to adulthood underlay shifts in both fertility and first reproduction. With steady improvements in offspring survival, the expected fertility required to satisfy a low risk of breeding failure became lower and observed maternal fertility subsequently declined through an earlier age at last reproduction. Postponement of the age at first reproduction began when this risk approximated zero-even for mothers starting reproduction late. Interestingly, despite vastly differing fertility rates at different stages of the transitions, the number of offspring successfully raised to breeding per mother remained relatively constant over the period. Our results stress the importance of assessing the long-term success of reproductive strategies by including measures of offspring quality and suggest that avoidance of breeding failure may explain several key features of recent life-history shifts in industrialized societies.

Maternal Risk of Breeding Failure Remained Low throughout the Demographic Transitions in Fertility and Age at First Reproduction in Finland

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Liu, Jianghua; Rotkirch, Anna; Lummaa, Virpi

2012-01-01

Radical declines in fertility and postponement of first reproduction during the recent human demographic transitions have posed a challenge to interpreting human behaviour in evolutionary terms. This challenge has stemmed from insufficient evolutionary insight into individual reproductive decision-making and the rarity of datasets recording individual long-term reproductive success throughout the transitions. We use such data from about 2,000 Finnish mothers (first births: 1880s to 1970s) to show that changes in the maternal risk of breeding failure (no offspring raised to adulthood) underlay shifts in both fertility and first reproduction. With steady improvements in offspring survival, the expected fertility required to satisfy a low risk of breeding failure became lower and observed maternal fertility subsequently declined through an earlier age at last reproduction. Postponement of the age at first reproduction began when this risk approximated zero–even for mothers starting reproduction late. Interestingly, despite vastly differing fertility rates at different stages of the transitions, the number of offspring successfully raised to breeding per mother remained relatively constant over the period. Our results stress the importance of assessing the long-term success of reproductive strategies by including measures of offspring quality and suggest that avoidance of breeding failure may explain several key features of recent life-history shifts in industrialized societies. PMID:22529952

Assessing the removal of organic micro-pollutants from anaerobic membrane bioreactor effluent by fertilizer-drawn forward osmosis

KAUST Repository

Kim, Youngjin

2017-03-23

In this study, the behavior of organic micro-pollutants (OMPs) transport including membrane fouling was assessed in fertilizer-drawn forward osmosis (FDFO) during treatment of the anaerobic membrane bioreactor (AnMBR) effluent. The flux decline was negligible when the FO membrane was oriented with active layer facing feed solution (AL-FS) while severe flux decline was observed with active layer facing draw solution (AL-DS) with di-ammonium phosphate (DAP) fertilizer as DS due to struvite scaling inside the membrane support layer. DAP DS however exhibited the lowest OMPs forward flux or higher OMPs rejection rate compared to other two fertilizers (i.e., mono-ammonium phosphate (MAP) and KCl). MAP and KCl fertilizer DS had higher water fluxes that induced higher external concentration polarization (ECP) and enhanced OMPs flux through the FO membrane. Under the AL-DS mode of membrane orientation, OMPs transport was further increased with MAP and KCl as DS due to enhanced concentrative internal concentration polarization while with DAP the internal scaling enhanced mass transfer resistance thereby lowering OMPs flux. Physical or hydraulic cleaning could successfully recover water flux for FO membranes operated under the AL-FS mode but only partial flux recovery was observed for membranes operated under AL-DS mode because of internal scaling and fouling in the support layer. Osmotic backwashing could however significantly improve the cleaning efficiency.

Comments on "Some Relations Among Cultural Traditions, Nuptiality and Fertility".

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Krotki, K J

1991-01-01

Facts employed in formulating Ansley Coale's interpretation of European historical demographic transition have largely been in the public domain for a long time. Coale's achievement, however, in bringing pertinent information together to form a theoretical framework is applauded, and is acknowledged as being an important contribution to the traditional use of demographic transition. Beyond this general interest and broad approval, the author critiques various points of Coale's thesis. First, he notes the need to be suspicious of high correlations found between mean age at 1st marriage and total fertility rate. Second, he is unsure of the role played by servants in explaining the comparatively later marriage age of western Europeans. Finally, the author considers marked fertility declines in China, Taiwan, and Korea. These declines run strongly counter to the traditional cultures of these countries. Moreover, the high life expectations at birth, strong episodic economic development in Taiwan and Korea, and serious autocratic government interference in China are atypical of experiences in most developing countries. Traditional family planning in these 3 countries was simply a facilitator of demographic transition. The experiences of China, Taiwan, Korea, and Bangladesh support the ineffectiveness of imposing programs from either within or outside of a country.

Nutrient losses from manure and fertilizer applications as impacted by time to first runoff event

International Nuclear Information System (INIS)

Smith, D.R.; Owens, P.R.; Leytem, A.B.; Warnemuende, E.A.

2007-01-01

Nutrient losses to surface waters following fertilization contribute to eutrophication. This study was conducted to compare the impacts of fertilization with inorganic fertilizer, swine (Sus scrofa domesticus) manure or poultry (Gallus domesticus) litter on runoff water quality, and how the duration between application and the first runoff event affects resulting water quality. Fertilizers were applied at 35 kg P ha -1 , and the duration between application and the first runoff event varied between 1 and 29 days. Swine manure was the greatest risk to water quality 1 day after fertilization due to elevated phosphorus (8.4 mg P L -1 ) and ammonium (10.3 mg NH 4 -N L -1 ) concentrations; however, this risk decreased rapidly. Phosphorus concentrations were 2.6 mg L -1 29 days after fertilization with inorganic fertilizer. This research demonstrates that manures might be more environmentally sustainable than inorganic fertilizers, provided runoff events do not occur soon after application. - Fertilization with manures results in lower nutrient runoff than inorganic fertilizers, especially if at least one week passes between fertilization and runoff

Study of the role of epididymal alpha-glucosidase in the fertility of male rats by the administration of the enzyme inhibitor castanospermine.

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Yeung, C H; Cooper, T G

1994-11-01

The activity of epididymal alpha-glucosidase in adult rats was rapidly suppressed to histochemically undetectable levels within 2 days by the continuous release of the enzyme inhibitor castanospermine via a peritoneal osmotic pump at a rate of 100-200 nmol h-1. It was established that mating activities overnight depleted 72% of the spermatozoa in the distal cauda, which was replenished in 2 days, and that fertility began to decline 3 weeks after efferent duct ligation. Male rats of proven mating proficiency and fertility were treated with castanospermine, or buffered saline as control, for up to 30 days and enzyme inhibition was confirmed at the end of treatment by histochemistry. Fertility was normal at the first mating test on day 7, significantly decreased at the second mating on day 9, but recovered in a stepwise manner at subsequent matings on days 12 and 14. Delaying the third mating until day 25 did not sustain the transient subfertility. However, prolonging sperm storage in the distal cauda epididymides and preventing replenishment with freshly matured spermatozoa, by efferent duct ligation for 14 days performed on day 15 during castanospermine administration, caused a decrease in fertility and a change in the kinematics of epididymal spermatozoa of the castanospermine-treated group. In control rats, binding of epididymal spermatozoa to Vicia faba, a lectin specific for glucose and glucosamine, and mannose and mannosamine residues, decreased from the proximal caput to the distal corpus coincident with the increase in alpha-glucosidase activity on the epithelial brush border. Lectin binding then increased in the cauda where enzyme activity was absent. However, castanospermine treatment did not significantly alter this binding profile. The findings suggest that epididymal alpha-glucosidase does not play a crucial role in the development of sperm fertilizing capacity, but may be involved in the preparation of spermatozoa for storage.

The changing contexts of fertility outcomes: case studies from a remote village in Bali, Indonesia.

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Withers, Mellissa; Browner, Carole H

2012-01-01

In the context of ready access to contraceptives, we sought to determine which individual and socio-cultural factors were most important in the dramatic fertility decline seen in an impoverished rural Balinese community. The study built on a 2002 longitudinal survey of 1528 Balinese reproductive-age married women that four years later found a significant proportion did not meet their expressed fertility aspirations. Four case studies of women whose expressed fertility intentions evolved over the study period are described. Culturally specific contextual factors (notably son preference), in interaction with increasing poverty, helped explained when and why their expressed fertility intentions changed. Moreover, many categorized in the second survey as not having meet their previously reported fertility aspirations were, in fact, intentionally spacing births. Although many women opted for smaller families than they actually wanted, and a decades-long, aggressive, two-child government campaign helped make them socially acceptable, contraception enabled the women to engage in strategic birth planning. We conclude that it is unrealistic to expect women in such settings, or indeed any setting, to give meaningful answers to questions in demographic surveys regarding future fertility aspirations.

Education Gains Attributable to Fertility Decline: Patterns by Gender, Period, and Country in Latin America and Asia.

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Li, Jing; Dow, William H; Rosero-Bixby, Luis

2017-08-01

We investigate the heterogeneity across countries and time in the relationship between mother's fertility and children's educational attainment-the quantity-quality (Q-Q) trade-off-by using census data from 17 countries in Asia and Latin America, with data from each country spanning multiple census years. For each country-year, we estimate micro-level instrumental variables models predicting secondary school attainment using number of siblings of the child, instrumented by the sex composition of the first two births in the family. We then analyze correlates of Q-Q trade-off patterns across countries. On average, one additional sibling in the family reduces the probability of secondary education by 6 percentage points for girls and 4 percentage points for boys. This Q-Q trade-off is significantly associated with the level of son preference, slightly decreasing over time and with fertility, but it does not significantly differ by educational level of the country.

Decline of semen quality and increase of leukocytes with cigarette smoking in infertile men

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Zhi Hong Zhang

2013-01-01

Full Text Available Background: Previous researches about the effect of smoking on semen quality are contradictory, and the mechanism behind the harmful effect of smoking on semen quality still remains unclear until today. Objective: The objectives of this study are evaluation of the relationship between smoking and fertility, investigation of the effects of cigarette smoking on sperm parameters and detection of presence of leukocytes within the semen of idiopathic infertile men from Northeastern China. Materials and Methods: A retrospective study of 1512 infertile patients who visited affiliated hospitals of Jilin University from 2007-2010 were enrolled in this study. Patients were assigned into one non-smoking and one smoking group which was divided into mild, moderate and heavy subgroups. Sperm parameters (including leukocytes and sperm morphology analysis were performed using standard techniques. Results: Compared with non-smokers, smokers had a significant decrease in semen volumes (p=0.006, rapid progressive motility (p=0.002 and sperm viability (p=0.019; moreover, smokers had a significant increase in the levels of immotile sperms (p=0.005 and semen leukocytes (p=0.002; pH and sperm concentration were not statistically significant (p=0.789 and p=0.297 respectively. Sperm motion parameters were all lower in the smokers except for beat-cross frequency (Hz (BCF. Further, the percentage of normal morphology sperm was decreased significantly in smokers (p=0.003, the sperm morphology was worse with increasing degree of smoking. Conclusion: These findings suggest that smoking leads to a significant decline in semen quality and higher levels of leukocytes, thus smoking may affects the fertilization efficiency.

Effects of fertilizers used in agricultural fields on algal blooms

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Chakraborty, Subhendu; Tiwari, P. K.; Sasmal, S. K.; Misra, A. K.; Chattopadhyay, Joydev

2017-06-01

The increasing occurrence of algal blooms and their negative ecological impacts have led to intensified monitoring activities. This needs the proper identification of the most responsible factor/factors for the bloom formation. However, in natural systems, algal blooms result from a combination of factors and from observation it is difficult to identify the most important one. In the present paper, using a mathematical model we compare the effects of three human induced factors (fertilizer input in agricultural field, eutrophication due to other sources than fertilizers, and overfishing) on the bloom dynamics and DO level. By applying a sophisticated sensitivity analysis technique, we found that the increasing use of fertilizers in agricultural field causes more rapid algal growth and decreases DO level much faster than eutrophication from other sources and overfishing. We also look at the mechanisms how fertilizer input rate affects the algal bloom dynamics and DO level. The model can be helpful for the policy makers in determining the influential factors responsible for the bloom formation.

Nano Fertilizers

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Hatice DAĞHAN

2017-06-01

Full Text Available Agricultural land is decreasing day by day due to erosion, environmental pollution, unconscious irrigation and fertilization. On the other hand, it is necessary to increase agricultural production in order to meet the needs of the developing industry as well as the nutritional needs of the growing population. In the recent years, nano fertilizers have begun to be produced to obtain the highest amount and quality of production from the unit area. Previous research shows that nano fertilizers cause an increase in the use efficiency of plant nutrients, reduce soil toxicity, minimize the potential adverse effects of excessive chemical fertilizer use, and reduce fertilizer application frequency. Nano fertilizers are important in agriculture to increase crop yield and nutrient use efficiency, and to reduce excessive use ofchemical fertilizers. The most important properties of these fertilizers are that they contain one or more of macro and micronutrients, they can be applied frequently in small amounts and are environmentally friendly. However, when applied at high doses, they exhibit decreasing effects on plant growth and crop yields, similar to chemical fertilizers. In this review, the definition, importan ce, and classification of nano fertilizers, their application in plant production, advantages and disadvantages and the results obtained in this field were discussed.

P wave dispersion and maximum P wave duration are independently associated with rapid renal function decline.

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Su, Ho-Ming; Tsai, Wei-Chung; Lin, Tsung-Hsien; Hsu, Po-Chao; Lee, Wen-Hsien; Lin, Ming-Yen; Chen, Szu-Chia; Lee, Chee-Siong; Voon, Wen-Chol; Lai, Wen-Ter; Sheu, Sheng-Hsiung

2012-01-01

The P wave parameters measured by 12-lead electrocardiogram (ECG) are commonly used as noninvasive tools to assess for left atrial enlargement. There are limited studies to evaluate whether P wave parameters are independently associated with decline in renal function. Accordingly, the aim of this study is to assess whether P wave parameters are independently associated with progression to renal end point of ≥25% decline in estimated glomerular filtration rate (eGFR). This longitudinal study included 166 patients. The renal end point was defined as ≥25% decline in eGFR. We measured two ECG P wave parameters corrected by heart rate, i.e. corrected P wave dispersion (PWdisperC) and corrected P wave maximum duration (PWdurMaxC). Heart function and structure were measured from echocardiography. Clinical data, P wave parameters, and echocardiographic measurements were compared and analyzed. Forty-three patients (25.9%) reached renal end point. Kaplan-Meier curves for renal end point-free survival showed PWdisperC > median (63.0 ms) (log-rank P = 0.004) and PWdurMaxC > median (117.9 ms) (log-rank Pfunction decline.

Economic analyses of rapid population growth.

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Birdsall, N

1989-01-01

"Discussion of the macroeconomic consequences of rapid population growth is organized into three schools: pessimists, optimists, and the recent revisionists. For the revisionists, differing views are presented about the pervasiveness and relevance of market failures, such as the negative externalities of childbearing, and about the ability of families and institutions to adjust rapidly to changes brought on by rapid population growth. A welfare economics approach is used to review the merits of various public policies to reduce fertility, including public financing of family planning services and taxes and incentives associated with childbearing." The focus is on developing countries. excerpt

Labor force participation and fertility: a study of married women in Bangladesh.

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Miah, M M; Mizan, A N

1992-01-01

Most researchers support the notion that a direct negative relationship exists between married women's labor force participation and fertility behavior, yet female employment shows no consistent, general relationship with declining fertility at individual and societal levels. Specific conditions under which employment lowers fertility are therefore explored for the case of Bangladesh. The economic, sociological, and world-system theoretical approaches to the relationship and empirical studies in developing countries including Bangladesh are reviewed. 1975-76 Bangladesh Fertility Survey data on births, deaths, nuptiality, and family planning knowledge and practice for 5772 currently married women of 6513 ever married women under 50 sampled are subjected to multivariate analysis for the study. Analysis revealed that women's modern and traditional occupation as well as higher and secondary education significantly lower their fertility, and that higher age, Islamic religion, use of modern contraceptives, and husband's occupation in transitional and modern sectors have significant positive effects on fertility. The correlation between higher fertility and contraceptive use may be due to women's delay in practicing family planning until reaching desired parity and/or high infant mortality driving women to cease practice in order to replace lost offspring. Future research should be conducted with larger samples and also consider occupations of both husbands and wives. Societal attitudes about women's education should be reformed in support of opening rural schools for women. With 90% of women residing in rural areas and women with traditional occupations having lower fertility, more traditional sector opportunities for women in cottage industry and agriculture production are also recommended, and would help balance skewed urban growth and hypertrophication of the tertiary sector. Finally, motivational efforts should be focused upon encouraging younger instead of older

Clonal structure and variable fertilization success in Florida Keys broadcast-spawning corals

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Miller, M. W.; Baums, I. B.; Pausch, R. E.; Bright, A. J.; Cameron, C. M.; Williams, D. E.; Moffitt, Z. J.; Woodley, C. M.

2018-03-01

Keystone reef-building corals in the Caribbean are predominantly self-incompatible broadcast spawners and a majority are threatened due to both acute adult mortality and poor recruitment. As population densities decline, concerns about fertilization limitation and effective population size in these species increase and would be further exacerbated by either high clonality or gametic incompatibility of parental genotypes. This study begins to address these concerns for two Caribbean broadcasting species by characterizing clonal structure and quantifying experimental pairwise fertilization success. Orbicella faveolata showed surprisingly high and contrasting levels of clonality between two sampled sites; Acropora palmata was previously known to be highly clonal. Individual pairwise crosses of synchronously spawning genotypes of each species were conducted by combining aliquots of gamete bundles immediately after spawning, and showed high and significant variability in fertilization success. Over half of the individual crosses of O. faveolata and about one-third of A. palmata crosses yielded ≤ 40% fertilization. Total sperm concentration was quantified in only a subset of O. faveolata crosses (range of 1-6 × 107 mL-1), but showed no correlation with fertilization success. We interpret that both parental incompatibility and individual genotypes with low-quality gametes are likely to have contributed to the variable fertilization observed with important implications for conservation. Differential fertilization success implies effective population size may be considerably smaller than hoped and population enhancement efforts need to incorporate many more parental genotypes at the patch scale to ensure successful larval production than indicated by estimates based simply on preserving levels of standing genetic diversity.

The role of oxidative stress in female infertility and in vitro fertilization

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Joanna Wojsiat

2017-05-01

Full Text Available Infertility problem involves many couples of reproductive age. It has been estimated that in Poland 0.7-1.0 million pairs require treatment, while for more than half of them assisted reproduction is the only recommended and effective method. Infertility affects 13 to 15% of the world’s population. A major concern is the age-related decline in female fertility even more that often a decision about pregnancy is taken at later age. Recent studies show that increased production of reactive oxygen species is an important factor in etiopathogenesis of pregnancy and affects female reproduction. It was found that oxidative stress may damage the oocytes and may impair their fertilization capacity. Oxidative stress may also lead to embryo fragmentation and formation of numerous developmental abnormalities, and is regarded to be one of the important reasons of spontaneous and recurrent miscarriage. Moreover, overproduction of reactive oxygen species has a significant impact on the success of in vitro fertilization (IVF.

Decrease in male mouse fertility by hydrogen sulfide and/or ammonia can Be inheritable.

Science.gov (United States)

Zhang, Weidong; Zhao, Yong; Zhang, Pengfei; Hao, Yanan; Yu, Shuai; Min, Lingjiang; Li, Lan; Ma, Dongxue; Chen, Liang; Yi, Bao; Tang, Xiangfang; Meng, Qingshi; Liu, Lei; Wang, Shukun; Shen, Wei; Zhang, Hongfu

2018-03-01

Numerous epidemiological studies suggest that air pollutants cause a decline in the quality of human spermatozoa and thus a reduction in fertility. However, the exact cause of infertility remains unknown. Air pollution gases, such as NH 3 and H 2 S are either free or bound to airborne particular materials (PM) and are abundant and reactive. The aim of this current investigation was to explore the impacts of NH 3 and/or H 2 S on male fertility and the underlying mechanisms. Male mouse exposed to H 2 S and/or NH 3 and after two generations were used to evaluate the impacts on fertility. The fertility, and spermatozoa quality parameters and proteins involved in spermatogenesis were investigated. Our current investigation demonstrates: i) H 2 S and/or NH 3 decrease male fertility by 20-30%, reduce the spermatozoa concentration about 20-40%, decrease 10-20%, increase around 30%; ii) the reduction in male fertility by H 2 S and/or NH 3 can be inheritable; iii) H 2 S and/or NH 3 can diminish male fertility through the disruption of spermatogenesis without affecting other body parameters such as body weight and organ index. One component of air pollutants, for example NH 3 , does not have a severe impact; however, two or more pollutants such as H 2 S and NH 3 combined can cause serious health problems, especially with regard to male fertility. We suggest that greater attention should be paid to these air pollutants to improve human health and fertility. Copyright © 2017 Elsevier Ltd. All rights reserved.

Role of Pigeonpea Cultivation on Soil Fertility and Farming System Sustainability in Ghana

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S. Adjei-Nsiah

2012-01-01

Full Text Available The productivity of the smallholder farming system in Ghana is under threat due to soil fertility decline. Mineral fertilizer is sparingly being used by smallholder farmers because of prohibitive cost. Grain legumes such as pigeonpea can play a complementary or alternative role as a source of organic fertilizer due to its ability to enhance soil fertility. Despite its importance, the potential of pigeonpea as a soil fertility improvement crop has not been exploited to any appreciable extent and the amount of land cultivated to pigeonpea in Ghana is vey negligible. This paper synthesizes recent studies that have been carried out on pigeonpea in Ghana and discusses the role of pigeonpea cultivation in soil fertility management and its implication for farming system sustainability. The paper shows that recent field studies conducted in both the semi-deciduous forest and the forest/savanna transitional agro-ecological zones of Ghana indicate that pigeonpea/maize rotations can increase maize yield by 75–200%. Barrier to widespread adoption of pigeonpea include land tenure, market, and accessibility to early maturing and high yielding varieties. The paper concludes among other things that in order to promote the cultivation of pigeonpea in Ghana, there is the need to introduce varieties that combine early maturity with high yields and other desirable traits based on farmers preferences.

Fertility and contraception in the Marshall Islands.

Science.gov (United States)

Levy, S J; Taylor, R; Higgins, I L; Grafton-Wasserman, D A

1988-01-01

Data on fertility and contraception in Micronesian women in the Marshall Islands were collected during a women's health survey in 1985. High total fertility rates were found. The reproductive pattern of many Marshallese women is one that has been associated with adverse health consequences: pregnancies in teenagers and in women over 39 years, high parities of four or more births, and short birth intervals. The practice of breastfeeding is declining in younger women. The prevalence of contraceptive use is low, and the availability of reversible methods is limited. Most contraceptive nonusers would like to practice contraception, but are inhibited by the lack of information about family planning. It is suggested that more attention needs to be given to family planning services in the Marshall Islands, in particular to improving the availability of reversible methods of contraception and of information about family planning. Further research is also needed on how family planning services might best be organized to maximize participation by women and their partners who wish to use such services.

The role of biological fertility in predicting family size

DEFF Research Database (Denmark)

Joffe, M; Key, J; Best, N

2009-01-01

for the first child. CONCLUSIONS: Within the limits of the available data quality, family size appears to be predicted by biological fertility, even after adjustment for maternal age, if the woman was at least 20 years old when the couple's first attempt at conception started. The contribution of behavioural......BACKGROUND: It is plausible that a couple's ability to achieve the desired number of children is limited by biological fertility, especially if childbearing is postponed. Family size has declined and semen quality may have deteriorated in much of Europe, although studies have found an increase....... Potential confounders were maternal age when unprotected sex began prior to the first birth, and maternal smoking. Desired family size was available in only one of the datasets. RESULTS: Couples with a TTP of at least 12 months tended to have smaller families, with odds ratios for the risk of not having...

Plugging the Baby Gap? The Struggle to Reverse Demographic Decline in Russia

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Alexandra Orlova

2015-01-01

Full Text Available Recently, Russia has been struggling to reverse plunging birthrates by adopting anumber of radical policies designed to encourage women to have more babies. The breakup of the Soviet Union and the ensuing economic and political instability prompted a decadelong decline in fertility rates, which dropped from 1.72 children per woman in 1991 to 1.2 children per woman in 2000. As a result, Russia lost nearly 6 million inhabitants. Relative stability and high oil prices in the decade that followed saw fertility rates settle at around 1.6 children per woman in 2012 and 1.71 children per woman in 2013, which is still below the needed replacement rate of 2.1 children per woman. This article focuses on the maternal capital subsidy for the birth of two or more children that took effect in 2007 and will run until 2016. It deals with two questions. The first question is, why has maternal capital fraud been so prevalent? The second question is, does maternal capital make a difference when it comes to increasing Russia’s birthrate? In exploring these questions, the article considers the future of maternal capital subsidy, specifically focusing on the social, economic, and political outcomes of the current Ukraine crisis and Russia’s annexation of the Crimean peninsula. The article concludes that the overly restrictive design of the maternal capital program provides afertile ground for fraud and that this subsidy fails to address the many complex causes underlying Russia’s declining fertility rates, thus limiting its effectiveness. Mothers and their families want the maternal capital money here and now because they do not believe that the money will be available in the future (in part, such belief is justified by the turbulent history of the 1990s and several bank collapses. The other side of the coin is that the state does not trust its citizens to use maternal capital money in a responsible fashion and has thus prescribed very limited usages for these

Low-fertility rate, market economy, and population control in China.

Science.gov (United States)

Wu, C; Mu, G

1996-01-01

This article discusses the increasingly market-oriented economy in China and the implications for family planning and population control. Modern China has experienced in a few decades a dramatic decline in fertility. Some new issues include whether faster population increase is harmless with a rapidly growing economy, and about whether a large population size offers greater opportunity to attract investment. China adopted its population policies against a specific historical context, and future policies will pertain to new issues. The baby boom of the mid-1970s led to population increase and the impossibility of limiting total population by 2000 to under 1.6 billion. China's huge population size has a significant adverse effect on the survival and development of the nation. Land and natural resources limit the nation's ability to accommodate greater numbers of people. 22% of land is hilly and habitable, but 78.9% is largely uninhabitable basins, mountains, and plateaus. 53% of lands are arid or semi-arid. 20.3% of China's population live under harsh natural conditions, and many are impoverished. 95% of China's population live in the eastern part of the country. Population pressure depletes resources and creates environmental problems. There is pressure on consumption of grain, and labor surpluses threaten modernization and create conflicts between egalitarianism and efficiency. Unemployment insurance and social security are not yet in place to cushion a shift to a competitive market system. Success in rural economic reform is tied to absorbing surplus rural labor. Family planning is critical to improving individual lives, a planned economy, and world responsibility. A market economy in China is likely to modernize attitudes toward reproduction and smooth the transition to a low, stable fertility, but government population control will still be needed. The unanswered question is through what means population will be controlled.

The declining effect of sibling size on children's education in Costa Rica

Directory of Open Access Journals (Sweden)

Jing Li

2014-12-01

Full Text Available Background: Costa Rica experienced a dramatic fertility decline in the 1960s and 1970s. The same period saw substantial improvement in children's educational attainment in Costa Rica. This correlation is consistent with household-level quantity-quality tradeoffs, but prior research on quantity-quality tradeoff magnitudes is mixed, and little research has estimated quantity-quality tradeoff behaviors in Latin America. Objective: This study explores one dimension of the potential demographic dividend from the fertility decline: the extent to which it was accompanied by quantity-quality tradeoffs leading to higher educational attainment. Specifically, we provide the first estimate of quantity-quality tradeoffs in Costa Rica, analyzing the increase in secondary school attendance among Costa Rican children as the number of siblings decreases. Furthermore, we advance the literature by exploring how that tradeoff has changed over time. Methods: We use 1984 and 2000 Costa Rican census data as well as survey data from the Costa Rican Longevity and Healthy Aging Study (CRELES. To address endogenous family size, the analysis uses an instrumental variable strategy based on the gender of the first two children to identify the causal relationship between number of siblings and children's education. Results: We find that, among our earlier cohorts, having fewer siblings is associated with a significantly higher probability of having attended at least one year of secondary school, particularly among girls. The effect is stronger after we account for the endogeneity of number of children born by the mother. For birth cohorts after 1980 this relationship largely disappears. Conclusions: This study provides strong evidence for a declining quantity-quality (Q-Q tradeoff in Costa Rica. This result suggests one potential explanation for the heterogeneous findings in prior studies elsewhere, but more work will be required to understand why such tradeoffs might vary

Poor people and poor fields? : integrating legumes for smallholder soil fertility management in Chisepo, central Malawi

NARCIS (Netherlands)

Kamanga, B.

2011-01-01

Soil infertility undermines the agriculture-based livelihoods in Malawi, where it is blamed for poor crop yields and the creation of cycles of poverty. Although technologies and management strategies have been developed to reverse the decline in soil fertility, they are under-used by smallholder

Effects of different fertilizers on methane emission from paddy field of ...

African Journals Online (AJOL)

deltafuture

Methane (CH4) emissions from Chinese paddy soil (Zhejiang province) were ... 52, 20 and 19 times, respectively of that given by control, and among chemical fertilizers it was ... The rapid increase of the world population over the past.

Declining trends in conception rates in recent birth cohorts of native Danish women: a possible role of deteriorating male reproductive health

DEFF Research Database (Denmark)

Jensen, Tina Kold; Sobotka, Thomás; Hansen, Martin A.

2008-01-01

lower TNCR and that in terms of their total fertility rate, the declining TNCR is compensated by an increasing use of ART. Our hypothesis of an ongoing birth cohort-related decline in fecundity was also supported by our finding of increasing and substantial use of ART in the management of infertility......Recent findings of poor semen quality among at least 20% of normal young men in Denmark prompted us to use unique Danish registers on births and induced abortions to evaluate a possible effect of the poor male fecundity on pregnancy rates among their presumed partners - the younger cohorts of women....... We have analysed data from the Danish birth and abortion registries as well as the Danish registry for assisted reproduction (ART) and defined a total natural conception rate (TNCR), which is equal to fertility rate plus induced abortion rate minus ART conception rate. A unique personal...

Declining trends in conception rates in recent birth cohorts of native Danish women: a possible role of deteriorating male reproductive health

DEFF Research Database (Denmark)

Jensen, T.K.; Sobotka, T.; Hansen, Marc Allan

2008-01-01

lower TNCR and that in terms of their total fertility rate, the declining TNCR is compensated by an increasing use of ART. Our hypothesis of an ongoing birth cohort-related decline in fecundity was also supported by our finding of increasing and substantial use of ART in the management of infertility......Recent findings of poor semen quality among at least 20% of normal young men in Denmark prompted us to use unique Danish registers on births and induced abortions to evaluate a possible effect of the poor male fecundity on pregnancy rates among their presumed partners--the younger cohorts of women....... We have analysed data from the Danish birth and abortion registries as well as the Danish registry for assisted reproduction (ART) and defined a total natural conception rate (TNCR), which is equal to fertility rate plus induced abortion rate minus ART conception rate. A unique personal...

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. Copyright © 2010 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

PTK2b function during fertilization of the mouse oocyte

International Nuclear Information System (INIS)

Luo, Jinping; McGinnis, Lynda K.; Carlton, Carol; Beggs, Hilary E.; Kinsey, William H.

2014-01-01

Highlights: • PTK2b is expressed in oocytes and is activated following fertilization. • PTK2b suppression in oocytes prevents fertilization, but not parthenogenetic activation. • PTK2b suppression prevents the oocyte from fusing with or incorporating bound sperm. • PTK2b suppressed oocytes that fail to fertilize do not exhibit calcium oscillations. - Abstract: Fertilization triggers rapid changes in intracellular free calcium that serve to activate multiple signaling events critical to the initiation of successful development. Among the pathways downstream of the fertilization-induced calcium transient is the calcium-calmodulin dependent protein tyrosine kinase PTK2b or PYK2 kinase. PTK2b plays an important role in fertilization of the zebrafish oocyte and the objective of the present study was to establish whether PTK2b also functions in mammalian fertilization. PTK2b was activated during the first few hours after fertilization of the mouse oocyte during the period when anaphase resumption was underway and prior to the pronuclear stage. Suppression of PTK2b kinase activity in oocytes blocked sperm incorporation and egg activation although sperm-oocyte binding was not affected. Oocytes that failed to incorporate sperm after inhibitor treatment showed no evidence of a calcium transient and no evidence of anaphase resumption suggesting that egg activation did not occur. The results indicate that PTK2b functions during the sperm-egg fusion process or during the physical incorporation of sperm into the egg cytoplasm and is therefore critical for successful development

PTK2b function during fertilization of the mouse oocyte

Energy Technology Data Exchange (ETDEWEB)

Luo, Jinping [Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160 (United States); McGinnis, Lynda K. [Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160 (United States); Carlton, Carol [Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160 (United States); Beggs, Hilary E. [Department of Ophthalmology, University of California, San Francisco, CA (United States); Kinsey, William H., E-mail: wkinsey@kumc.edu [Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160 (United States)

2014-08-01

Highlights: • PTK2b is expressed in oocytes and is activated following fertilization. • PTK2b suppression in oocytes prevents fertilization, but not parthenogenetic activation. • PTK2b suppression prevents the oocyte from fusing with or incorporating bound sperm. • PTK2b suppressed oocytes that fail to fertilize do not exhibit calcium oscillations. - Abstract: Fertilization triggers rapid changes in intracellular free calcium that serve to activate multiple signaling events critical to the initiation of successful development. Among the pathways downstream of the fertilization-induced calcium transient is the calcium-calmodulin dependent protein tyrosine kinase PTK2b or PYK2 kinase. PTK2b plays an important role in fertilization of the zebrafish oocyte and the objective of the present study was to establish whether PTK2b also functions in mammalian fertilization. PTK2b was activated during the first few hours after fertilization of the mouse oocyte during the period when anaphase resumption was underway and prior to the pronuclear stage. Suppression of PTK2b kinase activity in oocytes blocked sperm incorporation and egg activation although sperm-oocyte binding was not affected. Oocytes that failed to incorporate sperm after inhibitor treatment showed no evidence of a calcium transient and no evidence of anaphase resumption suggesting that egg activation did not occur. The results indicate that PTK2b functions during the sperm-egg fusion process or during the physical incorporation of sperm into the egg cytoplasm and is therefore critical for successful development.

The association between belief in God and fertility desires in Slovenia and the Czech Republic.

Science.gov (United States)

Cranney, Stephen

2015-06-01

Research on the association between religiosity and fertility-and, particularly, on the effects of secularization on fertility desires and outcomes-has been concerned primarily with mechanisms that are fundamentally institutional and are embedded in formal religious structures. Supplementary explanations focused on noninstitutional dimensions of religiosity have never been tested. Conventional ordinary least-squares regression was used to test the association between belief in God (i.e., a personal God or some sort of life force) and fertility desires among 2,251 women aged 18-45 in Slovenia and 951 women aged 15-44 in the Czech Republic who participated in the European Family and Fertility Survey in the mid-1990s. In both samples, substantial proportions of women either were nonbelievers or believed in God but were not institutionally religious. Belief in God was independently associated with fertility desires even in analyses controlling for self-reported religiosity. Women who believed in a personal God wanted approximately 0.2 more children, and those who believed in a life force wanted approximately 0.1 more children, than nonbelievers. Results were similar across several alternative measures of religiosity. At least some of the connection between religiosity and fertility apparently is attributable to metaphysical beliefs. Future research on the effect of secularization on fertility decline should investigate the potentially distinct effects of different dimensions of religiosity. Copyright © 2015 by the Guttmacher Institute.

Kootenay Lake Fertilization Experiment; Years 11 and 12, Technical Report 2002-2003.

Energy Technology Data Exchange (ETDEWEB)

Schindler, E.

2007-02-01

This report examines the results from the eleventh and twelfth years (2002 and 2003) of the Kootenay Lake fertilization experiment. Experimental fertilization has occurred with an adaptive management approach since 1992 in order to restore productivity lost as a result of upstream dams. One of the main objectives of the experiment is to restore kokanee (Oncorhynchus nerka) populations, which are a main food source for Gerrard rainbow trout (Oncorhynchus mykiss). Kootenay Lake is located between the Selkirk and Purcell mountains in southeastern British Columbia. It has an area of 395 km2, a maximum depth of 150 m, a mean depth of 94 m, and a water renewal time of approximately two years. The quantity of agricultural grade liquid fertilizer (10-34-0, ammonium polyphosphate and 28-0-0, urea ammonium nitrate) added to Kootenay Lake in 2002 and 2003 was similar to that added from 1992 to 1996. After four years of decreased fertilizer loading (1997 to 2000), results indicated that kokanee populations had declined, and the decision was made to increase the loads again in 2001. The total load of fertilizer in 2002 was 47.1 tonnes of phosphorus and 206.7 tonnes of nitrogen. The total fertilizer load in 2003 was 47.1 tonnes of phosphorus and 240.8 tonnes of nitrogen. Additional nitrogen was added in 2003 to compensate for nitrogen depletion in the epilimnion. The fertilizer was applied to a 10 km stretch in the North Arm from 3 km south of Lardeau to 3 km south of Schroeder Creek. The maximum surface water temperature in 2002, measured on July 22, was 22 C in the North Arm and 21.3 C in the South Arm. In 2003, the maxima were recorded on August 5 at 20.6 C in the North Arm and on September 2 at 19.7 C in the South Arm. The maximum water temperature in the West Arm was 18.7 C on September 2, 2003. Kootenay Lake had oxygen-saturated water throughout the sampling season with values ranging from about 11-16 mg/L in 2002 and 2003. In both years, Secchi depth followed the expected

Global Fertilizer and Manure, Version 1: Nitrogen Fertilizer Application

Data.gov (United States)

National Aeronautics and Space Administration — The Nitrogen Fertilizer Application dataset of the Global Fertilizer and Manure, Version 1 Data Collection represents the amount of nitrogen fertilizer nutrients...

Global Fertilizer and Manure, Version 1: Phosphorus Fertilizer Application

Data.gov (United States)

National Aeronautics and Space Administration — The Phosphorus Fertilizer Application dataset of the Global Fertilizer and Manure, Version 1 Data Collection represents the amount of phosphorus fertilizer nutrients...

Decline in the risk of hepatitis A virus infection in China, a country with booming economy and changing lifestyles.

Science.gov (United States)

Xu, Zhi-Yu; Wang, Xuan-Yi; Liu, Chang-Qing; Li, Yang-Ting; Zhuang, Fang-Chen

2008-10-01

The objective of the study was to identify the protective factors for the rapid decline in the risk of hepatitis A virus (HAV) infection in China between 1990 and 2006. Results of serological follow-up and data on annual hepatitis A incidence were analysed and correlated with economic growth and HAV vaccine output during the same period. In conclusion, both HAV vaccination and changing lifestyles associated with the booming economy contributed to the rapid risk decline. Changing lifestyles played a major role in the decline especially in the areas with booming economy.

[Speech by Oscar Julian Bardeci, director of the Centro Latinoamericano de Demografia (CELADE), at the Latinamerican Regional Meeting prior to the International Conference on Population in recognition of the Second Meeting on Population by the Committee of Upper-Level Government Experts (CEGAN), Havana, Cuba, November 16-19, 1983].

Science.gov (United States)

Bardeci, O J

1983-12-01

This work examines the relationship between population growth and economic development in Latin America and assesses progress in the 10 years since the Bucharest World Population Conference. The Latin American population increased from about 159 million in 1950 to 275 million in 1970 and around 325 million in 1980. The rate of growth reached a maximum of 2.8%/year in the early 1970s and has now declined to about 2.3%/year. The regional growth rate is a product of population dynamics that differ greatly in individual countries. Crude birth rates declined in every country of Latin America between 1975-80, but still exceeded 40/1000 in 1980-85 in Bolivia, Ecuador, El Salvador, Haiti, Honduras, and Nicaragua. Current fertility is the result of the different trajectories of the demographic transition in different countries. While fertility in Argentina, Cuba, and Uruguay underwent a slow but sustained decline that began prior to 1960, other countries including Colombia, Costa Rica, Chile, and Venezuela began an accelerated fertility decline in the 1960s that diffused rapidly through all age and social groups. Other countries have still not entered a definite phase of fertility decline. Mortality rates have declined appreciably in Latin America in the past few decades although they remain high in some countries. After the end of World War II and until the mid-1970s, most countries of the region experienced rapid economic growth coupled with profound changes in the productive structure. The industrial labor force grew in almost all countries along with urbanization, the decline of agricultural employment, and the increase of the tertiary sector. These and other important economic advances through the mid-1970s occurred despite rapid population growth, and the beginning of the fertility decline coincided with slowing economic growth that saw negative rates in 1981-82. Various studies have shown that not all population sectors were incorporated in the process of economic

Cohort fertility and educational expansion in the Czech Republic during the 20th century

Directory of Open Access Journals (Sweden)

Krystof Zeman

2018-05-01

Full Text Available Background: During the 20th century the Czech Republic went through profound changes in female employment, gender roles, population and family policies, and public childcare. The educational structure of the female population changed tremendously. At the same time, completed cohort fertility fluctuated between 1.8 and 2.2 children per woman. Objective: This article analyses the changes in the level of completed cohort fertility by education, during educational expansion in the Czech population under the economic, cultural, and institutional background of the state socialist regime, and after its breakdown. Methods: The changes in the level of completed cohort fertility by education are analysed by means of decomposition, complemented by the analysis of parity composition. Results: During the 20th century, education-specific completed cohort fertility increased, rather than declined. Fertility levels converged upwards, contributing to high uniformity within educational categories. The overall changes in fertility levels were driven by changes in the educational structure. These trends resulted in the dominance of the two-child family, while large families were disappearing and childlessness dropped to the biological minimum. Conclusions: An egalitarian economic system with traditional family-friendly policies, in combination with a family-unfriendly labour market, developed into a male breadwinner model of low gender equity. Future family policies should focus on the reconciliation of work and family. Contribution: The study contributes to the discussion on links between education and fertility, adding a new picture to the mosaic of country-level analyses. The Czech Republic is an example of a country with high educational homogeneity of fertility behaviour where the education-specific levels of fertility converged upwards.

Rapid bacterial mineralization of organic carbon produced during a phytoplankton bloom induced by natural iron fertilization in the Southern Ocean

Science.gov (United States)

Obernosterer, Ingrid; Christaki, Urania; Lefèvre, Dominique; Catala, Philippe; Van Wambeke, France; Lebaron, Philippe

2008-03-01

The response of heterotrophic bacteria ( Bacteria and Archaea) to the spring phytoplankton bloom that occurs annually above the Kerguelen Plateau (Southern Ocean) due to natural iron fertilization was investigated during the KErguelen Ocean and Plateau compared Study (KEOPS) cruise in January-February 2005. In surface waters (upper 100 m) in the core of the phytoplankton bloom, heterotrophic bacteria were, on an average, 3-fold more abundant and revealed rates of production ([ 3H] leucine incorporation) and respiration (bacterial metabolic activities were attributable to high-nucleic-acid-containing cells that dominated (≈80% of total cell abundance) the heterotrophic bacterial community associated with the phytoplankton bloom. Bacterial growth efficiencies varied between 14% and 20% inside the bloom and were bacterial activity, due to the stimulation by phytoplankton-derived dissolved organic matter. Within the Kerguelen bloom, bacterial carbon demand accounted for roughly 45% of gross community production. These results indicate that heterotrophic bacteria processed a significant portion of primary production, with most of it being rapidly respired.

[Women, fertility, development: the case of Rwanda].

Science.gov (United States)

Kabagwira, A

1992-08-01

Rwanda's high fertility rate and very rapid population growth have a negative impact on the welfare of women. Traditionally, women in Rwanda won the respect of their in-laws by having many children, on whom they depended for social status, help in agricultural work, and support in old age. Women also played a very important role in agricultural production in addition to their daily household activities. Migration of men and young people to urban areas has left many women totally in charge of agricultural production and has further deprived them of their limited leisure time. Low income, legal obstacles, literacy, custom and other factors limit women's resulting from their inferior social and juridical status conditions their reproductive behavior despite the development of a family planning program dating to 1981. The low level of female education is an important factor; 33% of women vs. 61% of men are literate. 25% of Rwanda's budget is devoted to education, but population growth has impeded progress Illiteracy implies a lack of receptivity to new ideas, including family planning. A 1983 fertility study in Rwanda showed that marriage age increased with education, from 18.8 years for illiterate women to 19.5 for those within 3-5 years. The number of children declined with the educational attainment of the mother, as did infant mortality rates. Considering the physical labor that women carry out, their repeated pregnancies are a handicap to the promotion of their own and their family's health. The prevailing high fertility exacerbates nutritional problems; some 20% of infants weigh less that 2.5 kg at birth. Efforts have recently been made to recognize the contribution of women and to elevate their status, such as improving their access to education, raising the legal marriage to 21, and prohibiting polygamy. The National Office of Population was created in 1981 to study population problems and take action to resolve them. The national population policy adopted in

Marital Processes, Arranged Marriage, and Contraception to Limit Fertility

Science.gov (United States)

Ghimire, Dirgha J.; Axinn, William G.

2013-01-01

An international transition away from familially-arranged marriages toward participation in spouse choice has endured for decades and continues to spread through rural Asia today. Though we know this transformation has important consequences for childbearing early in marriage, we know much less about longer-term consequences of this marital revolution. This study draws upon theories of family and fertility change and a rural Asian panel study designed to investigate changes in both marital and childbearing behaviors to investigate these long-term consequences. Controlling for social changes that shape both marital practices and childbearing behaviors, and explicitly considering multiple dimensions of marital processes, we find evidence consistent with an independent, long-standing association of participation in spouse choice with higher rates of contraception to terminate childbearing. These results add a new dimension to the evidence linking revolutions in marital behavior to long-term declines in fertility, but also motivate new research to consider a broader range of long-term consequences of changing marital processes. PMID:23709184

Mass-dependent predation risk as a mechanism for house sparrow declines?

OpenAIRE

MacLeod, Ross; Barnett, Phil; Clark, Jacquie; Cresswell, Will

2005-01-01

House sparrow (Passer domesticus) numbers have declined rapidly in both rural and urban habitats across Western Europe over the last 30 years, leading to their inclusion on the UK conservation red list. The decline in farmland has been linked to a reduction in winter survival caused by reduced food supply. This reduction in food supply is associated with agricultural intensification that has led to the loss of seed-rich winter stubble and access to spilt grain. However, urban house sparrows h...

COMPLETED FERTILITY DURING THE TWENTIETH CENTURY: AN EXAMPLE FROM SIX SETTLEMENTS IN NORTHERN GREECE.

Science.gov (United States)

Zafeiris, Konstantinos N; Kaklamani, Stamatina

2018-02-06

This study aimed to delineate temporal trends and differentials of completed fertility and their relationship with some characteristics of the marriage system in specific anthropological populations of northern Greece. The analysis was based on the life history of quinquennial and decennial birth cohorts of married women born in the 20th century who reproduced solely within the settlements studied. The variables studied were: children ever born, mean age of mother at first marriage, mean age of mother at first child (live birth), mean age of mother at last child and reproductive span. The results indicated that there were significant differences in the demographic characteristics of marriage and that there was an ongoing fertility transition in the 20th century in the populations studied. The mechanism of fertility decline was connected with the gradual reduction of the mean age of the mother at last child, the parallel decrease in the mean age at childbearing and a shortening of the reproductive span. Fertility levels at all times maintained a dynamic character imposed by local cultural, economic and social structures, which, in turn, were part of broader national and international structures, in all the populations studied. A strong trend of convergence of fertility levels was observed among the populations studied.

Diet-induced obesity in male C57BL/6 mice decreases fertility as a consequence of disrupted blood-testis barrier.

Directory of Open Access Journals (Sweden)

Yong Fan

Full Text Available Obesity is a complex metabolic disease that is a serious detriment to both children and adult health, which induces a variety of diseases, such as cardiovascular disease, type II diabetes, hypertension and cancer. Although adverse effects of obesity on female reproduction or oocyte development have been well recognized, its harmfulness to male fertility is still unclear because of reported conflicting results. The aim of this study was to determine whether diet-induced obesity impairs male fertility and furthermore to uncover its underlying mechanisms. Thus, male C57BL/6 mice fed a high-fat diet (HFD for 10 weeks served as a model of diet-induced obesity. The results clearly show that the percentage of sperm motility and progressive motility significantly decreased, whereas the proportion of teratozoospermia dramatically increased in HFD mice compared to those in normal diet fed controls. Besides, the sperm acrosome reaction fell accompanied by a decline in testosterone level and an increase in estradiol level in the HFD group. This alteration of sperm function parameters strongly indicated that the fertility of HFD mice was indeed impaired, which was also validated by a low pregnancy rate in their mated normal female. Moreover, testicular morphological analyses revealed that seminiferous epithelia were severely atrophic, and cell adhesions between spermatogenic cells and Sertoli cells were loosely arranged in HFD mice. Meanwhile, the integrity of the blood-testis barrier was severely interrupted consistent with declines in the tight junction related proteins, occludin, ZO-1 and androgen receptor, but instead endocytic vesicle-associated protein, clathrin rose. Taken together, obesity can impair male fertility through declines in the sperm function parameters, sex hormone level, whereas during spermatogenesis damage to the blood-testis barrier (BTB integrity may be one of the crucial underlying factors accounting for this change.

Nephrotic range proteinuria as a strong risk factor for rapid renal function decline during pre-dialysis phase in type 2 diabetic patients with severely impaired renal function.

Science.gov (United States)

Kitai, Yuichiro; Doi, Yohei; Osaki, Keisuke; Sugioka, Sayaka; Koshikawa, Masao; Sugawara, Akira

2015-12-01

Proteinuria is an established risk factor for progression of renal disease, including diabetic nephropathy. The predictive power of proteinuria, especially nephrotic range proteinuria, for progressive renal deterioration has been well demonstrated in diabetic patients with normal to relatively preserved renal function. However, little is known about the relationship between severity of proteinuria and renal outcome in pre-dialysis diabetic patients with severely impaired renal function. 125 incident dialysis patients with type 2 diabetes were identified. This study was aimed at retrospectively evaluating the impact of nephrotic range proteinuria (urinary protein-creatinine ratio above 3.5 g/gCr) on renal function decline during the 3 months just prior to dialysis initiation. In total, 103 patients (82.4 %) had nephrotic range proteinuria. The median rate of decline in estimated glomerular filtration rate (eGFR) in this study population was 0.98 (interquartile range 0.51-1.46) ml/min/1.73 m(2) per month. Compared to patients without nephrotic range proteinuria, patients with nephrotic range proteinuria showed significantly faster renal function decline (0.46 [0.24-1.25] versus 1.07 [0.64-1.54] ml/min/1.73 m(2) per month; p = 0.007). After adjusting for gender, age, systolic blood pressure, serum albumin, calcium-phosphorus product, hemoglobin A1c, and use of an angiotensin-converting enzyme inhibitor or an angiotensin II receptor blocker, patients with nephrotic range proteinuria showed a 3.89-fold (95 % CI 1.08-14.5) increased risk for rapid renal function decline defined as a decline in eGFR ≥0.5 ml/min/1.73 m(2) per month. Nephrotic range proteinuria is the predominant renal risk factor in type 2 diabetic patients with severely impaired renal function receiving pre-dialysis care.

The global decline of cheetah Acinonyx jubatus and what it means for conservation.

Science.gov (United States)

Durant, Sarah M; Mitchell, Nicholas; Groom, Rosemary; Pettorelli, Nathalie; Ipavec, Audrey; Jacobson, Andrew P; Woodroffe, Rosie; Böhm, Monika; Hunter, Luke T B; Becker, Matthew S; Broekhuis, Femke; Bashir, Sultana; Andresen, Leah; Aschenborn, Ortwin; Beddiaf, Mohammed; Belbachir, Farid; Belbachir-Bazi, Amel; Berbash, Ali; Brandao de Matos Machado, Iracelma; Breitenmoser, Christine; Chege, Monica; Cilliers, Deon; Davies-Mostert, Harriet; Dickman, Amy J; Ezekiel, Fabiano; Farhadinia, Mohammad S; Funston, Paul; Henschel, Philipp; Horgan, Jane; de Iongh, Hans H; Jowkar, Houman; Klein, Rebecca; Lindsey, Peter Andrew; Marker, Laurie; Marnewick, Kelly; Melzheimer, Joerg; Merkle, Johnathan; M'soka, Jassiel; Msuha, Maurus; O'Neill, Helen; Parker, Megan; Purchase, Gianetta; Sahailou, Samaila; Saidu, Yohanna; Samna, Abdoulkarim; Schmidt-Küntzel, Anne; Selebatso, Eda; Sogbohossou, Etotépé A; Soultan, Alaaeldin; Stone, Emma; van der Meer, Esther; van Vuuren, Rudie; Wykstra, Mary; Young-Overton, Kim

2017-01-17

Establishing and maintaining protected areas (PAs) are key tools for biodiversity conservation. However, this approach is insufficient for many species, particularly those that are wide-ranging and sparse. The cheetah Acinonyx jubatus exemplifies such a species and faces extreme challenges to its survival. Here, we show that the global population is estimated at ∼7,100 individuals and confined to 9% of its historical distributional range. However, the majority of current range (77%) occurs outside of PAs, where the species faces multiple threats. Scenario modeling shows that, where growth rates are suppressed outside PAs, extinction rates increase rapidly as the proportion of population protected declines. Sensitivity analysis shows that growth rates within PAs have to be high if they are to compensate for declines outside. Susceptibility of cheetah to rapid decline is evidenced by recent rapid contraction in range, supporting an uplisting of the International Union for the Conservation of Nature (IUCN) Red List threat assessment to endangered. Our results are applicable to other protection-reliant species, which may be subject to systematic underestimation of threat when there is insufficient information outside PAs. Ultimately, conserving many of these species necessitates a paradigm shift in conservation toward a holistic approach that incentivizes protection and promotes sustainable human-wildlife coexistence across large multiple-use landscapes.

Nitrogen uptake dynamics, yield and quality as influenced by nitrogen fertilization in Piel de sapo melon

Energy Technology Data Exchange (ETDEWEB)

Castellanos, M. T.; Cabello, M. J.; Cartagena, M. C.; Tarquis, A. M.; Arce, A.; Ribas, F.

2012-11-01

The need to reduce nitrogen (N) fertilizer pollution strengthens the importance of improving the utilization efficiency of applied N to crops. This requires knowledge of crop N uptake characteristics and how fertilization management affects it. A three-year field experiment was conducted from May to September in central Spain to investigate the influence of different N rates, which ranged from 11 to 393 kg ha{sup -}1, applied through drip irrigation, on the dynamics of N uptake, nitrogen use efficiency (NUE), fruit yield and quality of a Piel de sapo melon crop (Cucumis melo L. cv. Sancho). Both N concentration and N content increased in different plant parts with the N rate. Leaves had the highest N concentration, which declined by 40-50% from 34-41 days after transplanting (DAT), while the highest N uptake rate was observed from 30-35 to 70-80 DAT, coinciding with fruit development. In each year, NUE declined with increasing N rate. With N fertilizer applications close to the optimum N rate of 90-100 kg ha -1, the fruits removed approximately 60 kg N ha -1, and the amount of N in the crop residue was about 80 kg N ha -1; this serves to replenish the organic nutrient pool in the soil and may be used by subsequent crops following mineralization. (Author) 36 refs.

Effect of Various Organic Fertilizers Substitute Chemical Fertilizer on Cucumber Productions

International Nuclear Information System (INIS)

Piadang, Nattayana; Ratanapanit, Sittisuk; Chaowanklang, Pratuang; Ratanapanit; Nadtinee; Jaipakdee, Putinee; Ongsakitboriboon

2006-09-01

The effect of using the various organic fertilizer to substitute on the chemical fertilizer on cucumber, was carried out at Tambol Pattananikom, Amphur Pattananikom, Lopburi, Thailand, from December 1, 2005 to February 1, 2006 By using Randomized Comp let Block Design (RCBD), Contain with 4 treatments, chemical fertilizer: 16-16-16: 40 Kg/rai (Control), Pillet organic fertilizer: 50 Kg/rai, Bio extract from cow milk: 300 cc./ water 20 Ltr,.+ compost mixed in soil and bio fertilizer from the office of Atomic Energy Peace : 300 cc./water 20 Ltr. + campost mixed in soil (15 m. 2 /plot) were compared. Experiment result indicate that there were no significant differences on the yield. The highest yield of 25.91 kg/plot (27663.73 kg/rai) was obtained from chemical fertilizer, Fertilizer, followed by pillet organic fertilizer 22.88 kg/plot (2440.53 kg/rai), bio fertilizer 22.34 kg/pot (2382.93 kg/rai) and bio extract 19.03 kg/plot) (2029.87 kg/rai.

Standardization of fertilization protocols for the European eel, Anguilla anguilla

DEFF Research Database (Denmark)

Butts, Ian; Sørensen, Sune Riis; Politis, Sebastian Nikitas

2014-01-01

of this research were to provide a rapid, accurate and precise method to quantify sperm density by examining the relationship between sperm density and absorbance by use of a spectrophotometer, determine the optimal number of sperm required to fertilize eggs in a controlled setting, and explore how long eggs...... are receptive to fertilization post-stripping. Mean sperm density and absorbance at 350nm were 1.54e+10±4.95e+9sperm/mL and 1.91±0.22nm, respectively. Regression analysis demonstrated a highly significant positive relationship between sperm density and absorbance using a spectrophotometer at 350nm (R2=0.94, p

Periodontitis and Cognitive Decline in Alzheimer's Disease.

Directory of Open Access Journals (Sweden)

Mark Ide

Full Text Available Periodontitis is common in the elderly and may become more common in Alzheimer's disease because of a reduced ability to take care of oral hygiene as the disease progresses. Elevated antibodies to periodontal bacteria are associated with an increased systemic pro-inflammatory state. Elsewhere raised serum pro-inflammatory cytokines have been associated with an increased rate of cognitive decline in Alzheimer's disease. We hypothesized that periodontitis would be associated with increased dementia severity and a more rapid cognitive decline in Alzheimer's disease. We aimed to determine if periodontitis in Alzheimer's disease is associated with both increased dementia severity and cognitive decline, and an increased systemic pro inflammatory state. In a six month observational cohort study 60 community dwelling participants with mild to moderate Alzheimer's Disease were cognitively assessed and a blood sample taken for systemic inflammatory markers. Dental health was assessed by a dental hygienist, blind to cognitive outcomes. All assessments were repeated at six months. The presence of periodontitis at baseline was not related to baseline cognitive state but was associated with a six fold increase in the rate of cognitive decline as assessed by the ADAS-cog over a six month follow up period. Periodontitis at baseline was associated with a relative increase in the pro-inflammatory state over the six month follow up period. Our data showed that periodontitis is associated with an increase in cognitive decline in Alzheimer's Disease, independent to baseline cognitive state, which may be mediated through effects on systemic inflammation.

The Association Between Belief in God and Fertility Desires in Slovenia and the Czech Republic

Science.gov (United States)

Cranney, Stephen

2016-01-01

Context Research on the association between religiosity and fertility—and, particularly, on the effects of secularization on fertility desires and outcomes—has been concerned primarily with mechanisms that are fundamentally institutional and are embedded in formal religious structures. Supplementary explanations focused on noninstitutional dimensions of religiosity have never been tested. Methods Conventional ordinary least-squares regression was used to test the association between belief in God (i.e., a personal God or some sort of life force) and fertility desires among 2,251 women aged 18–45 in Slovenia and 951 women aged 15–44 in the Czech Republic who participated in the European Family and Fertility Survey in the mid-1990s. Results In both samples, substantial proportions of women either were nonbelievers or believed in God but were not institutionally religious. Belief in God was independently associated with fertility desires even in analyses controlling for self-reported religiosity. Women who believed in a personal God wanted approximately 0.2 more children, and those who believed in a life force wanted approximately 0.1 more children, than nonbelievers. Results were similar across several alternative measures of religiosity. Conclusions At least some of the connection between religiosity and fertility apparently is attributable to metaphysical beliefs. Future research on the effect of secularization on fertility decline should investigate the potentially distinct effects of different dimensions of religiosity. PMID:25682844

The demographic transition: an attempt to reformulate a population theory.

Science.gov (United States)

Hofsten, E

1981-01-01

In this effort to reformulate the demographic transition theory, attention is directed to the following: Malthus and Karl Marx's criticism of his principle of population; the 1st stage of transition, i.e., high mortality, high fertility, and slow population growth; the 2nd stage of declining mortality; the 3rd stage of declining fertility; the 4th stage when mortality and fertility are both low; the growth potential; and the demographic transition in the 3rd world countries. The demographic transition theory has become popular among demographers, economists, historians, and others interested in studying the development of population over time since the end of World War 2. This interest has most likely been created by the anxiety over the population explosion in the 3rd world countries. Transition has made demographers believe that the period of rapid population growth will be automatically succeeded by a period of more or less constant population size. The question that arises is whether it is as simple as that. Demographic transition has to a great extent taken the place of Malthus' principle of population as a general theory of population. Demographic transition appears to describe in a satisfactory way the development of population which all currently industrialized countires have passed through, when going from the preindustrial to the present industrialized stage. The objectives to demographic transition as a general theory are considered. Some of the factors which have accounted for the decline in fertility in Europe may also apply to the 3rd world countries. 1 such factor is the effect of reduced infant and child mortality on the individual level. The fertility decline, caused by reduced infant and child mortality may, however, be of limited size. The great amount of unemployment in the 3rd world may affect fertility in a downward direction. The fertility decline in Europe occurred simultaneously with an industrialization process, which gradually covered the

Perspectives of displaced Syrian women and service providers on fertility behaviour and available services in West Bekaa, Lebanon.

Science.gov (United States)

Kabakian-Khasholian, Tamar; Mourtada, Rima; Bashour, Hyam; Kak, Faysal El; Zurayk, Huda

2017-10-01

Prior to the conflict, Syria had relatively high fertility rates. In 2010, it had the sixth highest total fertility rate in the Arab World, but it witnessed a fertility decline before the conflict in 2011. Displacement during conflict influences fertility behaviour, and meeting the contraceptive needs of displaced populations is complex. This study explored the perspectives of women and service providers about fertility behaviour of and service provision to Syrian refugee women in Bekaa, Lebanon. We used qualitative methodology to conduct 12 focus group discussions with Syrian refugee women grouped in different age categories and 13 in-depth interviews with care providers from the same region. Our findings indicate that the displacement of Syrians to Lebanon had implications on the fertility behaviour of the participants. Women brought their beliefs about preferred family size and norms about decision-making into an environment where they were exposed to both aid and hardship. The unaffordability of contraceptives in the Lebanese privatised health system compared to their free provision in Syria limited access to family planning services. Efforts are needed to maintain health resources and monitor health needs of the refugee population in order to improve access and use of services.

Analysis of the relation between low fertility and living conditions among never-married women : Empirical evidence from survey data

OpenAIRE

MATSUDA Shigeki; SASAKI Takayuki; TAKAMURA Shizuka; OOSAWA Akiko; ONODA Hiromu; FUJISAWA Miho; UEMURA Hideki; ISHIDA Ayako

2015-01-01

The decline of birthrate since the mid-1970s is mainly due to the growing percentage of people not getting married. It is therefore essential to understand the factors underlying the trend of not marrying and enhance countermeasures against the falling fertility rate to stop the trend in order to recover the birthrate. With the purpose of figuring out the current trend of the declining birthrate and the situation of unmarried people, the Economic and Social Research Institute conducted the se...

Young female cancer patients' experiences with fertility counselling and fertility preservation

DEFF Research Database (Denmark)

Hoeg, Didde; Schmidt, Lone; Tryde Macklon, Kirsten

2016-01-01

were aware that chemotherapy could destroy their eggs. The participants described how specialized fertility counselling and fertility preservation contributed to a belief in life after cancer, which gave them hope that they would survive their cancer disease. Further, the women described how......Introduction: Fertility counselling for young women newly diagnosed with cancer is an important field of preconceptional counselling. This qualitative, small-scale study explored how young women newly diagnosed with cancer experienced specialized fertility preservation counselling and treatment...... in the public Danish health care system. Methods: Semi-structured, in-depth interviews were conducted with five women below 40 years recently diagnosed with cancer. All women received fertility counselling by a fertility specialist at the Fertility Clinic, University Hospital of Copenhagen, Denmark before...

On the spatial diffusion of fertility decline: the distance-to-clinic variable in a Chilean community.

Science.gov (United States)

Fuller, G

1974-10-01

Survey data collected in San Gregorio, Chile during 1967 were selected for an investigation of the importance of residence distance-from-clinic in the pattern of contraceptive acceptance. Data were obtained through interviews conducted with women of fertile age who resided in every 4th house in the community. 1163 household reports could be employed. This number included a total of 1612 women in their fertile years. The 1612 women could be divided into users of some means of contraception and non-users. Once the basic binary classification procedure has been applied, each available socioeconomic variable for users and non-users may then be compared to determine if a significant difference exists among the distribution of the variables for each group. The variables of abortions, recent births, and aspiration level were the most potent discriminators between users and non-users of birth control. The more conventional socioeconomic variables showed little discriminatory power. Distance was found to be a fairly powerful discriminator between the group of users and non-users. Several variables other than distance are correlated with birth control practice, but once the influence of the spatial variation of these correlates has been extracted, distance emerges as the single most powerful discriminator between users and non-users of contraceptive techniques. There thus appears to be a need to emphasize the distribution of contraceptive supply in order to reduce the distance which women must travel to obtain birth control information or devices.

Fertility decline; no mystery

Directory of Open Access Journals (Sweden)

Virginia Deane Abernethy

2002-05-01

Full Text Available ABSTRACT: The economic opportunity hypothesis states that perceived shrinkage of opportunity discourages women or couples from embarking on marriage or reproduction. On the contrary, the sense that opportunity is expanding encourages couples to raise their family-size target. The hypothesis assumes that humans are genetically programmed to maximize successful reproduction by having more offspring when environmental/economic conditions appear favorable, but exercise restraint --- waiting or limiting the total number of offspring --- if the latter strategy promises greater longrun success.

The impact of controlled nutrition during the dry period on dairy cow health, fertility and performance.

Science.gov (United States)

Beever, David E

2006-12-01

Average dairy herd fertility is declining, with more serves per successful conception, extended calving intervals and increased culling due to failure to rebreed, all adding significant costs to milk production. Genetics, management and nutrition have all contributed to this decline in fertility; the paper focuses primarily on nutritional issues. The extent of body condition loss after calving and its possible impact on fertility is considered, with evidence that this phenomenon is common in many herds irrespective of average milk yields. Body tissue mobilisation after calving increases the flux of non-esterified fatty acids to the liver and pathways of fatty acid metabolism are considered. Particular attention is given to the effects of high plasma non-esterified fatty acid levels on fat accumulation in liver cells and possible impacts on nitrogen and glucose metabolism. Current nutritional practices with early lactation cows which aim to stimulate milk yield and peak milk production but have been shown to exacerbate body condition loss, are reviewed. The paper also considers cow health issues during the peri-parturient period and how these may affect milk yield and fertility. It is concluded that current feeding practices for dry cows, with the provision of increasing amounts of the lactation ration during the Close-up period to accustom the rumen microbes and offset the expected reduction in feed intake as pregnancy reaches term, have largely failed to overcome peri-parturient health problems, excessive body condition loss after calving or declining fertility. From an examination of the energy and protein requirements of dry cows, it is suggested that current Close-up feeding practices can lead to luxury intakes of nutrients that can increase fat deposition in the viscera and the liver. Under such conditions, metabolism of nutrients by the cow may be compromised. In contrast, limited feeding throughout the whole dry period has been shown to prevent many of the

Education amplifies brain atrophy effect on cognitive decline: implications for cognitive reserve.

Science.gov (United States)

Mungas, Dan; Gavett, Brandon; Fletcher, Evan; Farias, Sarah Tomaszewski; DeCarli, Charles; Reed, Bruce

2018-08-01

Level of education is often regarded as a proxy for cognitive reserve in older adults. This implies that brain degeneration has a smaller effect on cognitive decline in those with more education, but this has not been directly tested in previous research. We examined how education, quantitative magnetic resonance imaging-based measurement of brain degeneration, and their interaction affect cognitive decline in diverse older adults spanning the spectrum from normal cognition to dementia. Gray matter atrophy was strongly related to cognitive decline. While education was not related to cognitive decline, brain atrophy had a stronger effect on cognitive decline in those with more education. Importantly, high education was associated with slower decline in individuals with lesser atrophy but with faster decline in those with greater atrophy. This moderation effect was observed in Hispanics (who had high heterogeneity of education) but not in African-Americans or Caucasians. These results suggest that education is an indicator of cognitive reserve in individuals with low levels of brain degeneration, but the protective effect of higher education is rapidly depleted as brain degeneration progresses. Copyright © 2018 Elsevier Inc. All rights reserved.

Uptake of crude petroleum hydrocarbons by mudflat bacteria ...

African Journals Online (AJOL)

SERVER

2007-08-06

Aug 6, 2007 ... bacteria exposed to nitrogenous fertilizer plant ... accompanied by a rapid decline in the level of crude petroleum in the amended .... conductivity, turbidity, salinity, dissolved oxygen (fresh sample only) ... Nutrient uptake was.

Recent fertility patterns of Finnish women by union status: A descriptive account

Directory of Open Access Journals (Sweden)

Marika Jalovaara

2013-02-01

Full Text Available BACKGROUND Remarkably little is known about the significance of consensual unions for fertility. This is true everywhere, but the lacuna is more important in the Nordic countries where there is so much childbearing outside of marriage, mostly in consensual unions. The purpose of this paper is to help fill this hole in our knowledge for Finland. OBJECTIVE Unusually good register data enable us to study recent fertility trends by union status (married, cohabiting, neither using records for some 112,000 Finnish women, or 11Š of all women at fertile ages. METHODS Our description of fertility is based on group-specific duration-based TFRs, which is the number of children borne by a woman who remains in the group throughout her reproductive life, as computed from the fertility rates for a synthetic cohort. This is an intuitively appealing metric that has been taken into systematic use only recently. RESULTS We find substantial fertility differences between women who cohabit, women who marry directly (i.e., without pre-marital cohabitation, and women who marry their cohabitational partner. As one would also expect in Finland, cohabiting women have much lower fertility than married women. The marital TFR is highest among the directly-married and declines monotonically as the length of pre-marital cohabitation increases, even when premarital childbearing is included in the count. As far as we know the latter relationship has not been shown before, because extensive data for complete cohabitational unions have not been available for other populations. CONCLUSIONS The Finnish data are unique, even among the Nordic countries, in that they contain individual-level life histories of family dynamics that cover consensual unions from their very start. Fertility analysis would benefit if data similar to the Finnish were to become available, because analyses that rely on civil status as an indicator of union status barely add anything to what we already know

Mangrove forest decline

DEFF Research Database (Denmark)

Malik, Abdul; Mertz, Ole; Fensholt, Rasmus

2017-01-01

Mangrove forests in the tropics and subtropics grow in saline sediments in coastal and estuarine environments. Preservation of mangrove forests is important for many reasons, including the prevention of coastal erosion and seawater intrusion; the provision of spawning, nursery, and feeding grounds...... of diverse marine biota; and for direct use (such as firewood, charcoal, and construction material)—all of which benefit the sustainability of local communities. However, for many mangrove areas of the world, unsustainable resource utilization and the profit orientation of communities have often led to rapid...... and severe mangrove loss with serious consequences. The mangrove forests of the Takalar District, South Sulawesi, are studied here as a case area that has suffered from degradation and declining spatial extent during recent decades. On the basis of a post-classification comparison of change detection from...

Adverse trends in male reproductive health and decreasing fertility rates

DEFF Research Database (Denmark)

Priskorn, Lærke; Holmboe, Stine; Jørgensen, Niels

2012-01-01

Healthy men produce an enormous number of sperms, far more than necessary for conception. However, several studies suggest that semen samples where the concentration of sperms is below 40 mill/mL may be associated with longer time to pregnancy or even subfertility, and specimens where the concent...... are now so low that we may be close to the crucial tipping point of 40 mill/mL spermatozoa. Consequently, we must face the possibility of more infertile couples and lower fertility rates in the future....... that the first decline in average sperm number of 20-40 mill/mL might not have had much effect on pregnancy rates, as the majority of men would still have had counts far above the threshold value. However, due to the assumed decline in semen quality, the sperm counts of the majority of 20 year old European men...

Fertility changes in Latin America in the context of economic uncertainty

Science.gov (United States)

Adsera, Alicia; Menendez, Alicia

2013-01-01

We explored the relation between fertility and the business cycle in Latin America during the last three decades. First, we used aggregate data on fertility rates and economic performance from a panel of 18 nations. Second, we studied these same associations in the transitions to 1st, 2nd, and 3rd births with DHS individual data from ten countries. In general, childbearing declines during downturns. This behaviour is mainly associated to increasing unemployment rather than slowdowns in GPD growth, although we find a positive relationship between first births rates and growth. While periods of unemployment may be a good time to have children because opportunity costs are lower, we find that maternity is reduced or postponed in particular among the most recent cohorts and among urban and more educated women. This is consistent with the idea that, in this context, income effects are dominant. PMID:21213181

Plasma leptin and growth hormone levels in the fine flounder (Paralichthys adspersus) increase gradually during fasting and decline rapidly after refeeding.

Science.gov (United States)

Fuentes, Eduardo N; Kling, Peter; Einarsdottir, Ingibjörg Eir; Alvarez, Marco; Valdés, Juan Antonio; Molina, Alfredo; Björnsson, Björn Thrandur

2012-05-15

In fish, recent studies have indicated an anorexigenic role of leptin and thus its possible involvement in regulation of energy balance and growth. In the present study, the effects of fasting and refeeding periods on plasma leptin levels were studied in the fine flounder, a flatfish with remarkably slow growth. To further assess the endocrine status of the fish during periods of catabolism and anabolism, plasma growth hormone (GH) levels were also analyzed. Under normal feeding condition, plasma leptin and GH levels remained stable and relatively high in comparison with other teleost species. For the three separate groups of fish, fasted for 2, 3, and 4 weeks, respectively, plasma leptin levels increase gradually, becoming significantly elevated after 3 weeks, and reaching highest levels after 4-week fasting. Plasma GH levels were significantly elevated after 2-week fasting. At the onset of refeeding, following a single meal, leptin levels decline rapidly to lower than initial levels within 2 h, irrespective of the length of fasting. Plasma GH also decline, the decrease being significant after 4, 24 and 2 h for the 2, 3 and 4-week fasted groups, respectively. This study shows that plasma leptin levels in the fine flounder are strongly linked to nutritional status and suggests that leptin secretion is regulated by fast-acting mechanisms. Elevated leptin levels in fasted fish may contribute to a passive survival strategy of species which experience natural food shortage periods by lowering appetite and limiting physical foraging activity. Copyright © 2012 Elsevier Inc. All rights reserved.

Impacts of long-term nitrogen fertilization on acid buffering rates and mechanisms of a slightly calcareous clay soil

NARCIS (Netherlands)

Zhang, Yuting; Vries, de Wim; Thomas, Ben W.; Hao, Xiying; Shi, Xiaojun

2017-01-01

Acidification of cropland soils is a serious problem in China that may cause long term pH decline, which threatens the sustainability of soil fertility and crop yields. The objective of this research was to investigate those rates and mechanisms for a slightly calcareous soil. The field data were

Impact of reverse nutrient diffusion on membrane biofouling in fertilizer-drawn forward osmosis

KAUST Repository

Li, Sheng

2017-05-31

Biofouling in fertilizer-drawn forward osmosis (FDFO) for water reuse was investigated by spiking pure bacteria species Pseudomonas aeruginosa PAO1+GFP and using three different fertilizers KNO3, KCl and KH2PO4 as draw solutions. The performance of FO process for treating synthetic wastewater was assessed and their influence on the membrane fouling and in particular biofouling was evaluated relative to the type of different fertilizers used and their rates of reverse diffusion. FO performances using KNO3 as draw solute exhibited severer flux decline (63%) than when using KCl (45%) and KH2PO4 (30%). Membrane autopsy indicated that the mass of organic foulants and biomass on fouled membrane surface using KNO3 as draw solute (947.5mg/m2 biopolymers, 72µm biofilm thickness and 53.3mg/m2 adenosine triphosphate) were significantly higher than that using KCl (450mg/m2 biopolymers, 33µm biofilm thickness and 28.2mg/m2 ATP) and KH2PO4 (440mg/m2 biopolymers, 35µm biofilm thickness and 33.5mg/m2 ATP). This higher flux decline is likely related to the higher reverse diffusion of KNO3 (19.8g/m2/h) than KCl (5.1g/m2/h) and KH2PO4 (3.7g/m2/h). The reverse diffused potassium could promote the organics and bacterial adhesion on FO membrane via charge screening effect and compression of electrical double layer. Moreover, reverse diffused nitrate provided increased N:P nutrient ratio was favorable for the bacteria to grow on the feed side of the FO membrane.

Effects of various organic and chemical fertilizers on growth indices of basil (Ocimum basilicum L.

Directory of Open Access Journals (Sweden)

S.M.K. Tahami

2016-05-01

Full Text Available In order to develop the high intensive agriculture, more chemical fertilizers are applied to the soil that resulting in soil degradation and environment deterioration. Application of organic manure is an important approach for maintaining and improving the soil fertility and increasing fertilizer use efficiency. Therefore, in order to evaluate the effect of organic manures and chemical fertilizer on growth indices and biological yield of basil (Ocimum basilicum L., an experiment was conducted at Research Station, Faculty of Agriculture, Ferdowsi University of Mashhad, Iran, during growing season of 2008-2009. A complete randomized block design with six treatments and three replications was used. The treatments were: cow manure, sheep manure, chicken manure, vermicompost, chemical NPK fertilizers and control (no fertilizer. The results showed that the use of organic fertilizers significantly increased seed and biological yield of basil compared with chemical fertilizer and control. The maximum and the minimum dry weights were observed at 105 days after planting, in sheep and cow manures, respectively. Gradually during the period of plant growth and development to reproduction phase percent of stem decreased and dry weight of inflorescence increased. The highest and the lowest leaf area index were observed at 90 days after planting, in cow manure and control, respectively, and then decreased in all treatments. The maximum crop growth rate in most of treatments at 90 days after planting was obtained, except the control which plant growth rate was lowest. Net assimilation rate (NAR in most treatments increased until 75 days after planting and then declined. While the highest and the lowest NAR were observed at 75 days after planting in chicken manure and chemical treatment, respectively.

Decline in Cardiovascular Mortality: Possible Causes and Implications.

Science.gov (United States)

Mensah, George A; Wei, Gina S; Sorlie, Paul D; Fine, Lawrence J; Rosenberg, Yves; Kaufmann, Peter G; Mussolino, Michael E; Hsu, Lucy L; Addou, Ebyan; Engelgau, Michael M; Gordon, David

2017-01-20

If the control of infectious diseases was the public health success story of the first half of the 20th century, then the decline in mortality from coronary heart disease and stroke has been the success story of the century's past 4 decades. The early phase of this decline in coronary heart disease and stroke was unexpected and controversial when first reported in the mid-1970s, having followed 60 years of gradual increase as the US population aged. However, in 1978, the participants in a conference convened by the National Heart, Lung, and Blood Institute concluded that a significant recent downtick in coronary heart disease and stroke mortality rates had definitely occurred, at least in the US Since 1978, a sharp decline in mortality rates from coronary heart disease and stroke has become unmistakable throughout the industrialized world, with age-adjusted mortality rates having declined to about one third of their 1960s baseline by 2000. Models have shown that this remarkable decline has been fueled by rapid progress in both prevention and treatment, including precipitous declines in cigarette smoking, improvements in hypertension treatment and control, widespread use of statins to lower circulating cholesterol levels, and the development and timely use of thrombolysis and stents in acute coronary syndrome to limit or prevent infarction. However, despite the huge growth in knowledge and advances in prevention and treatment, there remain many questions about this decline. In fact, there is evidence that the rate of decline may have abated and may even be showing early signs of reversal in some population groups. The National Heart, Lung, and Blood Institute, through a request for information, is soliciting input that could inform a follow-up conference on or near the 40th anniversary of the original landmark conference to further explore these trends in cardiovascular mortality in the context of what has come before and what may lie ahead. © 2017 American Heart

Effect of different nitrogen application types on nitrogen utilization efficiency and fate of fertilizer for sugacane

International Nuclear Information System (INIS)

Wei Jianfeng; Wei Dongping; Liu Huanyu; Chen Chaojun; Lan Libin; Liang He

2013-01-01

A pot experiment in greenhouse was conducted with "1"5N-labeled urea 5 g/pot (equal to 450 kg · hm"-"2) total nitrogen by three kinds of treatments of disposable bottom application nitrogen before sowing (T1), 50% nitrogen before sowing and 50% nitrogrn during tillering stage (T2), and 30% nitrogen before sowing, 30% nitrogen during tillering stage and 40% nitrogen applied during elongation stage (T3) to investigate the use efficiency and fate of fertilizer nitrogen using the sugarcane cultivar ROC22. Results showed that almost 18% ∼ 29% of total N uptake by sugarcane was supplied by fertilizer, and 71% ∼ 82% N derived from soil and seed-stem. Nitrogen use efficiency ranged from 21.0% to 34.52%, with "1"5N-fertilizer residue of 37.61% ∼ 44.13%, and "1"5N-fertilizer loss of 21.35% ∼ 41.39% among three treatments. Under the three levels of nitrogen application, residual was "1"5N-fertilizer was mainly distributed in 0 ∼ 20 cm top soil. The uptake of nitrogen and the proportion of total N from fertilizer in sugarcane plant, the yield of stalk and sugar after the nitrogen applied, and the use efficiency and residue ratio of "1"5N-fertilizer increased significantly over time, while loss rate of "1"5N-fertilizer decreased significantly with a slight decline trend of nitrogen distribution and sucrose accumulation in stalk. The results also indicated that after the nitrogen applied the amounts "1"5N-fertilizer residue in 0 ∼ 20 cm top soil showed a rising trend, but dropped in 20 ∼ 40 cm soil profile. From the viewpoints of economic benefit and ecological benefit, the nitrogen fertilizer applied of T3 could be optimal treatment. (authors)

Profiles of fertility, labour supply and wages of married women: a complete life-cycle model.

Science.gov (United States)

Moffitt, R

1984-01-01

Trends in fertility and female labor supply have changed dramatically since World War II. Fertility rates rose steadily from the 1940's until the early 1960's and thereafter declined, while female laborforce participation rates have continually grown since the 1950's. These 2 rates are closely linked. Labor supply and fertility decisions are also life-cycle decisions. In addition, wage and job prospects are related to job choice and in turn to fertility decisions. Labor supply, fertility, and wages are linked in an econometric model which takes into account the problems of heterogeneity of tastes, the problem of missing wage rates through nonworking, and the problem of simultaneous-equations bias. Past works are critiqued, mainly on the basis that few analyses recognize the interrelatedness of fertility and labor supply in any sense--static or dynamic. Nor do most researchers consider age-specific fertility equations in analyzing female labor supply. Moffitt's model is a beginning analysis of fertility and labor supply as a joint consumer-demand choice. Patterns of a couple's future consumption, wife's labor supply, and births are assumed to be planned at the beginning of marriage. These patterns depend on the constraints of budget, fertility, and of inverse production (the differing amounts of time it takes to care for a child as the child matures) as well as wage accumulation. Exogenous wealth and beginning wages are considered as well. This model does not account for a woman's work experience prior to marriage. According to the model, fertility rates rise in the 1st year of marriage and subsequently fall off. Employment rates drop off at an accelerating rate until the 6th year of marriage and then increase. A rise in wage level decreases the probability of birth and increases the probability ow working. Also, changes in fertility rates have more to do with wage changes than with a woman's cohort.

Fertility awareness online: the efficacy of a fertility education website in increasing knowledge and changing fertility beliefs.

Science.gov (United States)

Daniluk, J C; Koert, E

2015-02-01

How effective is online education in increasing knowledge of fertility and assisted reproductive technologies (ART), and changing beliefs about the timing of parenthood? Exposure to an online educational intervention resulted in immediate changes in participants' beliefs about the ideal timing of parenthood, and a significant increase in their knowledge of fertility and ART treatments and options; most of these changes were not sustained over time, particularly for men. Research has identified significant gaps in men's and women's knowledge of fertility and ART, contributing to the trend to delay childbearing. Effective educational programs need to be developed, to support informed fertility and child-timing decisions. Pre-post intervention study of 199 currently childless men and women, and a 6-month follow-up of 110 of these participants. One hundred and ninety-nine childless participants between the ages of 18 and 35 were asked to complete 4 beliefs and 22 knowledge questions prior to, and immediately after, reading 10 online posts related to: fertility testing and preservation, fertility history and lifespan, the effects of health and fitness on fertility, and assisted reproduction. Six months later, 110 of the original sample repeated the 26-item survey. Participants' fertility and ART knowledge scores increased significantly immediately after the intervention, as did their confidence in their fertility and ART knowledge. Participants' beliefs about the ideal and latest age a woman or man should consider producing a child decreased. However, 6 months later, participants' beliefs and knowledge levels largely returned to their pre-intervention levels, particularly for the men in the study. The sample size and the recruitment methods may limit the generalizability of these findings. Previous studies have demonstrated the short-term efficacy of online educational approaches to increase fertility knowledge and support informed family planning decisions. Web

Understory Vegetative Diversity of Post-Thinned Pine Plantations Treated with Fertilizer, Fire and Herbicide in East Texas

International Nuclear Information System (INIS)

Oswald, B.P.; Williams, H.M.; Farrish, K.W.; Ott, B.; Van Kley, J.E.

2009-01-01

This study assessed biodiversity in the understory of two pine plantations where different management tools (fertilizer, prescribed burning, and herbicide application) were utilized. During three growing seasons, species, percent cover, and number of individuals, and physical characteristics were recorded. Responses to treatment were examined based on comparison of species richness, evenness, diversity, and importance. Two years after treatment, fertilized plots showed a decline in species richness, evenness, and diversity. Prescribed burning and herbicide treatments increased species richness but decreased species evenness, resulting in no change in diversity index. Herbicide treatment reduced the importance of dominant shrubs and increased the importance of disturbance-adapted species.

Understory Vegetative Diversity of Post-Thinned Pine Plantations Treated with Fertilizer, Fire and Herbicide in East Texas

Directory of Open Access Journals (Sweden)

Brian P. Oswald

2009-01-01

Full Text Available This study assessed biodiversity in the understory of two pine plantations where different management tools (fertilizer, prescribed burning, and herbicide application were utilized. During three growing seasons, species, percent cover, and number of individuals, and physical characteristics were recorded. Responses to treatment were examined based on comparison of species richness, evenness, diversity, and importance. Two years after treatment, fertilized plots showed a decline in species richness, evenness, and diversity. Prescribed burning and herbicide treatments increased species richness but decreased species evenness, resulting in no change in diversity index. Herbicide treatment reduced the importance of dominant shrubs and increased the importance of disturbance-adapted species.

Shifting terrestrial feedbacks from CO2 fertilization to global warming

Science.gov (United States)

Peñuelas, Josep; Ciais, Philippe; Janssens, Ivan; Canadell, Josep; Obersteiner, Michael; Piao, Shilong; Vautard, Robert; Sardans Jordi Sardans, Jordi

2016-04-01

Humans are increasingly fertilizing the planet. Our activities are increasing atmospheric concentrations of carbon dioxide, nitrogen inputs to ecosystems and global temperatures. Individually and combined, they lead to biospheric availability of carbon and nitrogen, enhanced metabolic activity, and longer growing seasons. Plants can consequently grow more and take up more carbon that can be stored in ecosystem carbon pools, thus enhancing carbon sinks for atmospheric CO2. Data on the increased strength of carbon sinks are, however, inconclusive: Some data (eddy covariance, short-term experiments on elevated CO2 and nutrient fertilization) suggest that biospheric carbon uptake is already effectively increasing but some other data suggest it is not, or are not general and conclusive (tree-ring, forest inventory). The combined land-ocean CO2 sink flux per unit of excess atmospheric CO2 above preindustrial levels declined over 1959-2012 by a factor of about 1/3, implying that CO2 sinks increased more slowly than excess CO2. We will discuss the available data, and the discussion will drive us to revisit our projections for enhanced carbon sinks. We will reconsider the performance of the modulators of increased carbon uptake in a CO2 fertilized and warmed world: nutrients, climate, land use and pollution. Nutrient availability in particular plays a crucial role. A simple mass-balance approach indicates that limited phosphorus availability and the corresponding N:P imbalances can jointly reduce the projected future carbon storage by natural ecosystems during this century. We then present a new paradigm: we are shifting from a fertilization to a warming era. Compared to the historical period, future impacts of warming will be larger than the benefits of CO2 fertilization given nutrient limitations, management and disturbance (which reduces C stocks and thus sequestration potential) and because CO2 will decrease by 2050 in RCP2.6, meaning loss of CO2 fertilization, and CO2

Fertility and Population Policy

OpenAIRE

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

2018-01-01

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

Loneliness and the rate of motor decline in old age: the rush memory and aging project, a community-based cohort study

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Arnold Steven E

2010-10-01

Full Text Available Abstract Background Being alone, as measured by less frequent social interactions, has been reported to be associated with a more rapid rate of motor decline in older persons. We tested the hypothesis that feeling alone is associated with the rate of motor decline in community-dwelling older persons. Methods At baseline, loneliness was assessed with a 5-item scale in 985 persons without dementia participating in the Rush Memory and Aging Project, a longitudinal community-based cohort study. Annual detailed assessment of 9 measures of muscle strength and 9 motor performances were summarized in a composite measure of global motor function. Results Linear mixed-effects models which controlled for age, sex and education, showed that the level of loneliness at baseline was associated with the rate of motor decline (Estimate, -0.016; S.E. 0.006, p = 0.005. For each 1-point higher level of loneliness at baseline, motor decline was 40% more rapid; this effect was similar to the rate of motor decline observed in an average participant 4 years older at baseline. Furthermore, this amount of motor decline per year was associated with about a 50% increased risk of death. When terms for both feeling alone (loneliness and being alone were considered together in a single model, both were relatively independent predictors of motor decline. The association between loneliness and motor decline persisted even after controlling for depressive symptoms, cognition, physical and cognitive activities, chronic conditions, as well as baseline disability or a history of stroke or Parkinson's disease. Conclusions Among community-dwelling older persons, both feeling alone and being alone are associated with more rapid motor decline, underscoring the importance of psychosocial factors and motor decline in old age.

Evaluating Infertility

Science.gov (United States)

... decreases rapidly after age 37 years. By age 40 years, a woman’s chance of getting pregnant drops to less than 10% per menstrual cycle. A man’s fertility also declines with age, but not as predictably. ...

A look at Asia's changing youth population.

Science.gov (United States)

Xenos, P; Kabamalan, M; Westley, S B

1999-01-01

This report summarizes findings from a recent East-West Center study on demographic and social changes among young people aged 15-24 years in 17 countries in East, Southeast, and South Asia. Nearly every country in Asia has experienced fertility decline. Decline began in Japan and Singapore during the 1950s, followed by declines in Hong Kong, South Korea, Sri Lanka, the Philippines, Brunei, Taiwan, Malaysia, Thailand, and China during the 1960s. Declines occurred during the 1970s in Indonesia, India, and Myanmar. A "youth bulge" occurred about 20 years later due to declines in infant and child mortality. This bulge varies by country with the timing and magnitude of population growth and subsequent fertility decline. The proportion of youth population rises from 16% to 18% about 20 years after the beginning of fertility decline and declines to a much lower stable level after several decades. The bulge is large in countries with rapid fertility decline, such as China. Governments can minimize the effects of bulge on population growth by raising the legal age at marriage, lengthening the interval between first marriage and first birth, and increasing birth intervals. School enrollments among adolescents are rising. In South Korea, the population aged 15-24 years increased from 3.8 to 8.8 million during 1950-90, a rise of 132% compared to a rise of 653% among school enrollments. It is expected that the number of out-of-school youths will decline from 5.1 to 3.6 million during 1990-2025. Youth employment varies by gender. Policies/programs in family planning and reproductive health will need to address the changing needs of youth population.

Integrated nutrient management, soil fertility, and sustainable agriculture: Current issues and future challenges

OpenAIRE

Goletti, F.; Gruhn, P.; Yudelman, M.

2000-01-01

Metadata only record The challenge for agriculture over the coming decades will be to meet the world's increasing demand for food in a sustainable way. Declining soil fertility and mismanagement of plant nutrients have made this task more difficult. In their 2020 Vision discussion paper, Peter Gruhn, Francesco Goletti, and Montague Yudelman point out that as long as agriculture remains a soil-based industry, major increases in productivity are unlikely to be attained without ensuring that ...

Women, Demography, and Politics: How Lower Fertility Rates Lead to Democracy.

Science.gov (United States)

Sommer, Udi

2018-04-01

Where connections between demography and politics are examined in the literature, it is largely in the context of the effects of male aspects of demography on phenomena such as political violence. This project aims to place the study of demographic variables' influence on politics, particularly on democracy, squarely within the scope of political and social sciences, and to focus on the effects of woman-related demographics-namely, fertility rate. I test the hypothesis that demographic variables-female-related predictors, in particular-have an independent effect on political structure. Comparing countries over time, this study finds a growth in democracy when fertility rates decline. In the theoretical framework developed, it is family structure as well as the economic and political status of women that account for this change at the macro and micro levels. Findings based on data for more than 140 countries over three decades are robust when controlling not only for alternative effects but also for reverse causality and data limitations.

Ginkgo biloba extract and long-term cognitive decline: a 20-year follow-up population-based study.

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Hélène Amieva

Full Text Available Numerous studies have looked at the potential benefits of various nootropic drugs such as Ginkgo biloba extract (EGb761®; Tanakan® and piracetam (Nootropyl® on age-related cognitive decline often leading to inconclusive results due to small sample sizes or insufficient follow-up duration. The present study assesses the association between intake of EGb761® and cognitive function of elderly adults over a 20-year period.The data were gathered from the prospective community-based cohort study 'Paquid'. Within the study sample of 3612 non-demented participants aged 65 and over at baseline, three groups were compared: 589 subjects reporting use of EGb761® at at least one of the ten assessment visits, 149 subjects reporting use of piracetam at one of the assessment visits and 2874 subjects not reporting use of either EGb761® or piracetam. Decline on MMSE, verbal fluency and visual memory over the 20-year follow-up was analysed with a multivariate mixed linear effects model. A significant difference in MMSE decline over the 20-year follow-up was observed in the EGb761® and piracetam treatment groups compared to the 'neither treatment' group. These effects were in opposite directions: the EGb761® group declined less rapidly than the 'neither treatment' group, whereas the piracetam group declined more rapidly (β = -0.6. Regarding verbal fluency and visual memory, no difference was observed between the EGb761® group and the 'neither treatment' group (respectively, β = 0.21 and β = -0.03, whereas the piracetam group declined more rapidly (respectively, β = -1.40 and β = -0.44. When comparing the EGb761® and piracetam groups directly, a different decline was observed for the three tests (respectively β = -1.07, β = -1.61 and β = -0.41.Cognitive decline in a non-demented elderly population was lower in subjects who reported using EGb761® than in those who did not. This effect may be a specific medication

Semen collection and fertility in naturally fertile sandhill cranes

Science.gov (United States)

Chen, G.; Gee, G.F.; Nicolich, Jane M.; Taylor, J.A.; Urbanek, R.P.; Stahlecker, D.W.

1997-01-01

Aviculturists often ask if semen collection will interfere with fertility in naturally fertile pairs of cranes. We used 12 naturally fertile Florida sandhill crane (Grus canadensis pratensis) pairs for this study, 6 control and 6 experimental. All pairs had produced fertile eggs in previous years and were in out-of-doors pens scattered throughout different pen complexes, within auditory range but physically isolated. Semen was collected on Tuesday mornings and Friday afternoons from 26 February 1993 to 4 June 1993. We used standard artificial insemination methods to collect and to evaluate the semen and spermatozoa. Semen collection did not affect semen quality or quantity. Semen volume, sperm density, sperm motility, sperm morphology, sperm live, sperm number per collection, and male response to semen collection exhibited significant daily variation (P semen collection began 13 days before the first egg in the experimental group, we observed no differences in the date of first egg laid or in fertility between experimental and control groups. Also, we observed no differences in the interval between clutches or in the percentage of broken eggs between experimental and control groups. Sires consistently producing better semen samples produced fewer fertile eggs than sires producing poorer semen samples (r = 0.60).

Fertilizers in cereals crops. Effect of fertilization in grain quality

International Nuclear Information System (INIS)

Melaj, Mariana

1997-01-01

In the last years the yields of the maize cultivation in the Pampeana production region have constantly increased, foreseeing higher increases of yield in the next years. Such increase is due, between other motives, to the use of hybrids of higher potential yield. There is a direct relation between the yield potential of a genotype and the nutrients demand, fact that constitutes one of the geneticists concerns. Maize hybrids reach its maximum expression when the plant is cultivated in good supplied soils with balanced quantities of nutrients that in several cases are reached with the practice of fertilization. The quantitative and qualitative vegetal response to the use of phosphate fertilizers depend of soils, of the environmental conditions, of fertilizer and the way of its application as well as of the maize hybrid that was used. To direct the practice of fertilization towards the reposition of the soil nutrients extracted by genotypes of high yield without producing excesses that increase costs and put in danger the environment, it is necessary to know the real coefficient used by the plants of the phosphorus available in the soils. The isotopic methodology allows to distinguish the phosphorus coming from two nutrient sources: soil and fertilizer, even in the juvenile phase of vegetal development and to evaluate the efficiency of fertilizers in plant nutrition. The objective of the present work was to evaluate the use of phosphorus coming from one of the phosphorus source available (soil, fertilizer), that should allow to increase and make more specific the knowledge's level of the different maize hybrids. This is obtained by determination of the grade of use of nutrient (of the soil) and of the nutrient of fertilizers, evaluating the qualitative and quantitative responses to fertilization

Utilization of 15N in the sequence of mineral fertilizer - forage - animal - slurry - forage

International Nuclear Information System (INIS)

Peschke, H.

1981-01-01

After systematic application of 15 N-ammonium nitrate, the change of the dinuclidic composition and 15 N quantity was studied by isotope analysis of several open systems in the sequence mineral fertilizer - (soil) - forage - (animal) - slurry - (soil) - forage. The relative 15 N isotope frequency of 50 atom% in the mineral fertilizer declined to 12.2 to 21.4 atom% in the forage (beet, oats, hay) and went down to 3.15 atom% in the slurry of a dairy cow fed on this forage. Silage maize manured with the slurry of the dairy cow only showed 1.98 atom %, green oats grown after the silage maize on the same area was found to have 0.45 atom%. The 15 N quantity of 104.5 g N in the fertilizer gradually decreased to 41.6 g N in the forage, 30.5 g N in the slurry and 22.6 g N in the silage maize. The causes discussed are 15 N isotope dilution as qualitative factor and productive and unproductive N losses as quantitative factors. (author)

Fate of 15N-labelled urea fertilizer under conditions of tropical flooded-rice culture

International Nuclear Information System (INIS)

Krishnappa, A.M.; Shinde, J.E.

1980-01-01

The fate of an initial pulse of 15 N urea (at the rate of 100 kg N.ha -1 ) was followed under conditions of tropical flooded-rice culture over a sequence of three crops and two intercrop fallows. The total crop recovery accounted for 24.3% of the added fertilizer nitrogen. Ammonia volatilization and leaching losses amounted to 9.7% and 7.5%, respectively. The major losses of the fertilizer nitrogen occurred during the crop season immediately following its application. At the end of the experiment, 26.5% of the fertilizer nitrogen was recovered in the root zone in the Kjeldahl fraction and 0.9% as clay-fixed, non-exchangeable ammonium-N. Total recovery thus amounted to about 69%. The maximum contribution of the 15 N pulse to the NO 3 -N content of the groundwater (about 2%) occurred in the first crop season. It had declined below 0.2% by the third crop season. Throughout the experimental period the total NO 3 -N concentration of the groundwater never exceeded 3.2 ppm. (author)

Amphibian and reptile declines over 35 years at La Selva, Costa Rica.

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Whitfield, Steven M; Bell, Kristen E; Philippi, Thomas; Sasa, Mahmood; Bolaños, Federico; Chaves, Gerardo; Savage, Jay M; Donnelly, Maureen A

2007-05-15

Amphibians stand at the forefront of a global biodiversity crisis. More than one-third of amphibian species are globally threatened, and over 120 species have likely suffered global extinction since 1980. Most alarmingly, many rapid declines and extinctions are occurring in pristine sites lacking obvious adverse effects of human activities. The causes of these "enigmatic" declines remain highly contested. Still, lack of long-term data on amphibian populations severely limits our understanding of the distribution of amphibian declines, and therefore the ultimate causes of these declines. Here, we identify a systematic community-wide decline in populations of terrestrial amphibians at La Selva Biological Station, a protected old-growth lowland rainforest in lower Central America. We use data collected over 35 years to show that population density of all species of terrestrial amphibians has declined by approximately 75% since 1970, and we show identical trends for all species of common reptiles. The trends we identify are neither consistent with recent emergence of chytridiomycosis nor the climate-linked epidemic hypothesis, two leading putative causes of enigmatic amphibian declines. Instead, our data suggest that declines are due to climate-driven reductions in the quantity of standing leaf litter, a critical microhabitat for amphibians and reptiles in this assemblage. Our results raise further concerns about the global persistence of amphibian populations by identifying widespread declines in species and habitats that are not currently recognized as susceptible to such risks.

Education as policy: the impact of education on marriage, contraception, and fertility in Colombia, Peru, and Bolivia.

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Heaton, T B; Forste, R

1998-01-01

Using data from the World Fertility and Demographic and Health Surveys of Colombia, Peru, and Bolivia, we model the effects of education on three demographic outcomes: the timing of first sexual union, contraceptive use, and fertility. These effects are examined over time and across geographic areas using a multivariate framework. We find substantial improvements in female educational attainment over the last fifty years and a strong relationship between education and the demographic outcomes. Each successive increment in education is associated with declines in the marriage rate, increased contraceptive use, and lower fertility. Education accounts for some of the changes over time in the demographic outcomes, but the pattern varies by outcome, time period, and geographic area. In support of the social diffusion hypothesis, our results indicate that educational differences in reproductive behavior are reduced as the level of development increases and societies pass through their demographic transition.

Changes in Fertility at the Population Level in the Era of ART in Rural Malawi.

Science.gov (United States)

McLean, Estelle; Price, Alison; Chihana, Menard; Kayuni, Ndoliwe; Marston, Milly; Koole, Olivier; Zaba, Basia; Crampin, Amelia

2017-08-01

HIV reduces fertility through biological and social pathways, and antiretroviral treatment (ART) can ameliorate these effects. In northern Malawi, ART has been available since 2007 and lifelong ART is offered to all pregnant or breastfeeding HIV-positive women. Using data from the Karonga Health and Demographic Surveillance Site in Malawi from 2005 to 2014, we used total and age-specific fertility rates and Cox regression to assess associations between HIV and ART use and fertility. We also assessed temporal trends in in utero and breastfeeding HIV and ART exposure among live births. From 2005 to 2014, there were 13,583 live births during approximately 78,000 person years of follow-up of women aged 15-49 years. The total fertility rate in HIV-negative women decreased from 6.1 [95% confidence interval (CI): 5.5 to 6.8] in 2005-2006 to 5.1 (4.8-5.5) in 2011-2014. In HIV-positive women, the total fertility rate was more stable, although lower, at 4.4 (3.2-6.1) in 2011-2014. In 2011-2014, compared with HIV-negative women, the adjusted (age, marital status, and education) hazard ratio was 0.7 (95% CI: 0.6 to 0.9) and 0.8 (95% CI: 0.6 to 1.0) for women on ART for at least 9 months and not (yet) on ART, respectively. The crude fertility rate increased with duration on ART up to 3 years before declining. The proportion of HIV-exposed infants decreased, but the proportion of ART-exposed infants increased from 2.4% in 2007-2010 to 3.5% in 2011-2014. Fertility rates in HIV-positive women are stable in the context of generally decreasing fertility. Despite a decrease in HIV-exposed infants, there has been an increase in ART-exposed infants.

Comparison of unenriched versus 15N-enriched fertilizer as a tracer for N fertilizer uptake

International Nuclear Information System (INIS)

Meints, V.W.; Shearer, G.; Kohl, D.H.; Kurtz, L.T.

1975-01-01

A greenhouse experiment was conducted on three soils with differing cropping and fertilization histories to determine whether unenriched fertilizer N can be used in the same manner as 15 N-enriched fertilizer to estimate the amount of plant N derived from fertilizer. Estimates using unenriched fertilizer N were compared with estimates using two 15 N enrichment levels. Use of unenriched fertilizer N led to underestimation of the amount of fertilizer N in the plant material in four of six cases when compared to 15 N-enriched fertilizer. Standard deviations of the estimates of fertilizer-derived N in plant material were considerably greater when unenriched fertilizer was used. (U.S.)

Reconstruction of spatially detailed global map of NH4+ and NO3- application in synthetic nitrogen fertilizer

Science.gov (United States)

Nishina, Kazuya; Ito, Akihiko; Hanasaki, Naota; Hayashi, Seiji

2017-02-01

Currently, available historical global N fertilizer map as an input data to global biogeochemical model is still limited and existing maps were not considered NH4+ and NO3- in the fertilizer application rates. This paper provides a method for constructing a new historical global nitrogen fertilizer application map (0.5° × 0.5° resolution) for the period 1961-2010 based on country-specific information from Food and Agriculture Organization statistics (FAOSTAT) and various global datasets. This new map incorporates the fraction of NH4+ (and NO3-) in N fertilizer inputs by utilizing fertilizer species information in FAOSTAT, in which species can be categorized as NH4+- and/or NO3--forming N fertilizers. During data processing, we applied a statistical data imputation method for the missing data (19 % of national N fertilizer consumption) in FAOSTAT. The multiple imputation method enabled us to fill gaps in the time-series data using plausible values using covariates information (year, population, GDP, and crop area). After the imputation, we downscaled the national consumption data to a gridded cropland map. Also, we applied the multiple imputation method to the available chemical fertilizer species consumption, allowing for the estimation of the NH4+ / NO3- ratio in national fertilizer consumption. In this study, the synthetic N fertilizer inputs in 2000 showed a general consistency with the existing N fertilizer map (Potter et al., 2010) in relation to the ranges of N fertilizer inputs. Globally, the estimated N fertilizer inputs based on the sum of filled data increased from 15 to 110 Tg-N during 1961-2010. On the other hand, the global NO3- input started to decline after the late 1980s and the fraction of NO3- in global N fertilizer decreased consistently from 35 to 13 % over a 50-year period. NH4+-forming fertilizers are dominant in most countries; however, the NH4+ / NO3- ratio in N fertilizer inputs shows clear differences temporally and geographically. This

Projected near-future levels of temperature and pCO2 reduce coral fertilization success.

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Rebecca Albright

Full Text Available Increases in atmospheric carbon dioxide (pCO2 are projected to contribute to a 1.1-6.4°C rise in global average surface temperatures and a 0.14-0.35 reduction in the average pH of the global surface ocean by 2100. If realized, these changes are expected to have negative consequences for reef-building corals including increased frequency and severity of coral bleaching and reduced rates of calcification and reef accretion. Much less is known regarding the independent and combined effects of temperature and pCO2 on critical early life history processes such as fertilization. Here we show that increases in temperature (+3°C and pCO2 (+400 µatm projected for this century negatively impact fertilization success of a common Indo-Pacific coral species, Acropora tenuis. While maximum fertilization did not differ among treatments, the sperm concentration required to obtain 50% of maximum fertilization increased 6- to 8- fold with the addition of a single factor (temperature or CO2 and nearly 50- fold when both factors interact. Our results indicate that near-future changes in temperature and pCO2 narrow the range of sperm concentrations that are capable of yielding high fertilization success in A. tenuis. Increased sperm limitation, in conjunction with adult population decline, may have severe consequences for coral reproductive success. Impaired sexual reproduction will further challenge corals by inhibiting population recovery and adaptation potential.

Getting a piece of the pie? The economic boom of the 1990s and declining teen birth rates in the United States.

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Colen, Cynthia G; Geronimus, Arline T; Phipps, Maureen G

2006-09-01

In the United States, the 1990s was a decade of dramatic economic growth as well as a period characterized by substantial declines in teenage childbearing. This study examines whether falling teen fertility rates during the 1990s were responsive to expanding employment opportunities and whether the implementation of the Personal Responsibility and Work Opportunities Act (PRWORA), increasing rates of incarceration, or restrictive abortion policies may have affected this association. Fixed-effects Poisson regression models were estimated to assess the relationship between age-specific birth rates and state-specific unemployment rates from 1990 to 1999 for Black and White females aged 10-29. Falling unemployment rates in the 1990s were associated with decreased childbearing among African-American women aged 15-24, but were largely unrelated to declines in fertility for Whites. For 18-19 year-old African-Americans, the group for whom teen childbearing is most normative, our model accounted for 85% of the decrease in rates of first births. Young Black women, especially older teens, may have adjusted their reproductive behavior to take advantage of expanded labor market opportunities.

[Economic activity of Third World women and perspectives on the decline of their fertility].

Science.gov (United States)

Samman, M L

1983-01-01

addressed only to men. Although migration for many women had a fertility dampening effect, for many others it reinforced their attachment to reproductive traditions. The maintenance of high levels of fertility among Third World women, despite their participation in paid labor, can be explained in part by tradition and religious values and productive roles of children, but also by dissatisfaction with the low level employment conditions available to them.

Fertility behaviour of working women in Saudi Arabia: a special case of King Saud University, Riyadh.

Science.gov (United States)

Khraif, Rshood; Abdul Salam, Asharaf; Al-Mutairi, Abdullah; Elsegaey, Ibrahim

2018-03-15

Fertility levels and their determinants in Saudi Arabia have not been studied sufficiently for formulating family policy, although some attention has been paid to rapid fertility transitions in the context of socioeconomic and cultural change. This study focused on the fertility of a particular occupational category in the Kingdom of Saudi Arabia to assess determinants of fertility, measured as the number of children. The sample was drawn from the King Saud University staff - ever-married Saudi Arabian women. Results found that proximate factors (age, age at first marriage, intended number of children, length of marriage and contraceptive use) were significant in predicting fertility behaviour, whereas geographic, social and economic factors were insignificant. Thus, the fertility behaviour of this occupational group seems unique. This might be due to the special characteristics and lifestyle of this particular occupational group. The effect of the intended number of children on the actual number signified the fertility behaviour of this group of women. This, expectedly, should improve the influence of social and economic factors on fertility behaviour, in the future. Thus, advocates, policies and programmes (population and public health) at the societal and familial levels, should consider the demographic change in the social and economic context.

African land degradation in a world of global atmospheric change: fertilization conceals degradation?

Science.gov (United States)

Le, Lulseged Tamene, Paul L. G. Vlek, Quang Bao

2009-04-01

Land degradation is one of the most widespread environmental problems worldwide. The sub-Saharan Africa (SSA) is one of the most seriously affected regions with huge implications on food security and economic development. To plan plausible management measures, understanding the magnitude of the problem and identification of hotspot areas are necessary. Analysis of remote sensing and climate data observed from space for the period 1982 - 2003 showed significant improvement in vegetation productivity across 30% of SSA with decline on 5% of the subcontinent. Global change in atmospheric chemistry is likely responsible for the observed increasing trend in vegetation productivity. Such widespread greening observed from space could mask anthropogenic land degradation processes such as land conversion, selective logging, and soil nutrient mining. To assess this possible masking effect, a re-analysis of the vegetation productivity dynamics, taking into account atmospheric fertilization, was conducted. This was performed by analyzing the long-term trend in vegetation productivity of pristine lands (areas with minimum human- and climate- related impacts) identified across different biomes in SSA. The baseline slope values of biomass accrual calculated for those pristine lands were estimated and used to re-calculate the long-term trend of green biomass with and without the impact of atmospheric fertilization. This ultimately enabled to delineate the areas that would have experienced significant loss in vegetation productivity had the atmospheric chemistry not changed. The result suggests that seven times more than the area of actual productivity decline in SSA is affected by land degradation processes that are concealed by atmospheric fertilization. With this rate of surreptitious loss of vital land attributes and with the current rate of population growth (3%), the SSA subcontinent may soon lack the land resources necessary to foster economic development. Spatially

Fertility transition and social stratification in the town of Alghero, Sardinia (1866-1935

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Marco Breschi

2014-03-01

Full Text Available Background: Despite the large amount of research on European fertility transition, the mechanisms of this demographic process are still poorly understood. This is particularly true in the Italian demographic experience, especially for some regions. Objective: We wish to improve the knowledge of the determinants of fertility transition in Sardinia, a region situated in the heart of the Mediterranean but paradoxically one which is the least "Mediterranean‟ region of the country. The analysis of SES differentials and their evolution over the transition process is the core purpose of this paper Methods: We use a complex individual database deriving from the combination of civil and religious sources of Alghero, a large costal town in north-western Sardinia. Our analysis is focussed on the reproductive history of Alghero marriage cohorts (1866-1905, followed through the mid-1930s. A micro-level statistical analysis is performed on legitimate births of parity 2+. Results: We find that, in the period under examination, the process of fertility decline already underway in the northern and central regions, was almost absent in Alghero. However we did prove significant socio-economic differentials in marital fertility. The "elite" group shows the first clear signs of deliberate marital fertility control. Conclusions: The results testify to a new and more conscious attitude towards birth control adopted by the elite minority, while no significant change is detectable for the rest of the population until the 1930s. This is the first research carried out at the individual level related to an urban population in Southern Italy.

Effects of Multiple Stressors on Red Abalone (Haliotis rufescens) Fertilization Success

Science.gov (United States)

Boch, C. A.; Aalto, E.; De Leo, G.; Litvin, S.; Lovera, C.; Micheli, F.; Woodson, C. B.; Monismith, S. G.; Barry, J. P.

2016-02-01

Acidification, hypoxia, and ocean warming are escalating threats in the world's coastal waters, with potentially severe consequences for marine life and ocean-based economies. In particular, eastern boundary current ecosystems, including the California Current Large Marine Ecosystem (CCLME), are experiencing large-scale declines in pH and dissolved oxygen (DO)—with the latter linked to changes in thermal stratification and shoaling of the oxygen minimum zone. To examine the consequences of ocean acidification and other climate-related changes in oceanographic conditions on nearshore marine populations within the CCLME, we are assessing the potential effects of current and future upwelling-type conditions on the population dynamics of the red abalone (Haliotis rufescens), with a focus on sensitive early life history phases (e.g., fertilization, larval development, and juvenile growth and survival) expected to be important determinants of population dynamics. Here, we present the first experimental results on the impacts of combined exposures of low pH and low DO on abalone fertilization success. Our results show that abalone fertilization success is significantly reduced when the gametes are exposed to a decrease in seawater pH from 8.0 to 7.2. Furthermore, low pH in combination with hypoxic exposure—e.g., a decrease in dissolved oxygen from 6 mg/L DO to 1 mg/L DO—does not further decrease fertilization rates, suggesting a lack of synergistic or additive effects of these multiple stressors on the reduction of fertilization success. Although the focus of this study is to characterize the effects of multiple stressors on the early life history of abalone, the implications of these results are expected to be relevant for a variety of marine taxa with similar reproductive modes.

Reexamining the Impact of Family Planning Programs on US Fertility: Evidence from the War on Poverty and the Early Years of Title X†

Science.gov (United States)

Bailey, Martha J.

2012-01-01

Almost 50 years after domestic US family planning programs began, their effects on childbearing remain controversial. Using the county-level roll-out of these programs from 1964 to 1973, this paper reevaluates their shorter and longer term effects on US fertility rates. I find that the introduction of family planning is associated with significant and persistent reductions in fertility driven both by falling completed childbearing and childbearing delay. Although federally funded family planning accounted for a small portion of the post-baby boom US fertility decline, my estimates imply that they reduced childbearing among poor women by 19 to 30 percent. (JEL I38, J12, J13, J18) PMID:22582135

Nutrient use efficiencies and crop responses to N, P and manure applications in Zimbabwean soils: Exploring management strategies across soil fertility gradients

NARCIS (Netherlands)

Tittonell, P.A.; Zingore, S.; Wijk, van M.T.; Corbeels, M.; Giller, K.E.

2007-01-01

The spatial variability in crop yields commonly observed in smallholder farms of sub-Saharan Africa is often caused by gradients of declining soil fertility with increasing distance from the homestead. This heterogeneity means that recommendations based on regional soil surveys are of limited value.

Girl child marriage and its effect on fertility in Pakistan: findings from Pakistan Demographic and Health Survey, 2006-2007.

Science.gov (United States)

Nasrullah, Muazzam; Muazzam, Sana; Bhutta, Zulfiqar A; Raj, Anita

2014-04-01

Child marriage (before 18 years) is prevalent in Pakistan, which disproportionately affects young girls in rural, low income and low education households. Our study aims to determine the association between early marriage and high fertility and poor fertility health indicators among young women in Pakistan beyond those attributed to social vulnerabilities. Nationally representative data from Pakistan Demographic and Health Survey, 2006-2007, a cross-sectional observational survey, were limited to ever-married women aged 20-24 years (n = 1,560; 15% of 10,023) to identify differences in poor fertility outcomes [high fertility (three or more childbirths); rapid repeat childbirth (marriage. Associations between child marriage and fertility outcomes were assessed by calculating adjusted odds ratios (AORs) using logistic regression models after controlling for demographics, social equity indicators (education, wealth index, rural residence), contraception use, marriage duration and culture-specific factors (husband's desire for more children, son preference). Overall, 50% of ever-married women aged 20-24 years in Pakistan were married before the age of 18 years. Girl child marriage was significantly (p marriage was significantly associated with high fertility (AOR 6.62; 95% CI 3.53-12.43), rapid repeat childbirth (AOR 2.88; 95% CI 1.83-4.54), unwanted pregnancy (AOR 2.90; 95% CI 1.75-4.79), and pregnancy termination (AOR 1.75; 95% CI 1.10-2.78). Girl child marriage affects half of all ever-married women aged 20-24 years in Pakistan, and increases their risk for high fertility and poor fertility health indicators, highlighting the need of increasing the age of marriage among women in Pakistan. Efforts to eliminate girl child marriage by strict law enforcement, promoting civil, sexual and reproductive health rights for women can help eliminate girl child marriage in Pakistan.

Soil Fertility Gradient in the Restinga Ecosystem

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América Castelar da Cunha, Joana; Casagrande, José Carlos; Soares, Marcio Roberto; Martins Bonilha, Rodolfo

2013-04-01

The restinga ecosystem (coastal plain vegetation) can be termed as a set of plant communities that suffer strong influenced by fluvial and marine factors and is characterized as an ecosystem of great biological diversity, therefore, represents areas of great importance in the context of ecological preservation. The degradation processes from many forms of anthropogenic disturbances that has taken place since the colonization of the country, made studies on the characterization and dynamics of soil fertility of these areas even more important in relation to the maintenance of its biodiversity and conservation. The sites studied were the Cardoso Island and Comprida Island, and in these, we analyzed four physiognomies, restinga, low restinga, dune and antedune (from continent to ocean). Chemical analyses were performed and soil salinity in these areas in depths 0-5; 0-10; 0-20; 20-40; 40-60 cm. In all soils the cationic exchange capacity was intimately associated with the concentration of soil organic matter, which makes this parameter essential to the maintenance of soil fertility of these areas; in more superficial layers (0-20 cm) there was an increase of pH and base saturation and decline of organic matter, aluminum saturation and cationic exchange capacity in the nearby sea, physiognomies what determines the existence of fertility gradient towards the continent-coast; restinga forests showed a chemical standard that is heavily marked by sandy texture, high degree of leaching, nutrient poverty, low base saturation, high saturation by aluminum and acidity, opposite conditions to soils of the dunes and antedunes, with the exception of sandy texture; despite the existence of a chemical gradient of fertility among the physiognomies studied it is possible to determine the soil acts more strongly as a physical support than as provider of fertility; as for salinity, soil collected in Cardoso Island did not present salinity in any depth, a fact which can be explained due

Declination Calculator

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Declination is calculated using the current International Geomagnetic Reference Field (IGRF) model. Declination is calculated using the current World Magnetic Model...

Functional network integrity presages cognitive decline in preclinical Alzheimer disease.

Science.gov (United States)

Buckley, Rachel F; Schultz, Aaron P; Hedden, Trey; Papp, Kathryn V; Hanseeuw, Bernard J; Marshall, Gad; Sepulcre, Jorge; Smith, Emily E; Rentz, Dorene M; Johnson, Keith A; Sperling, Reisa A; Chhatwal, Jasmeer P

2017-07-04

To examine the utility of resting-state functional connectivity MRI (rs-fcMRI) measurements of network integrity as a predictor of future cognitive decline in preclinical Alzheimer disease (AD). A total of 237 clinically normal older adults (aged 63-90 years, Clinical Dementia Rating 0) underwent baseline β-amyloid (Aβ) imaging with Pittsburgh compound B PET and structural and rs-fcMRI. We identified 7 networks for analysis, including 4 cognitive networks (default, salience, dorsal attention, and frontoparietal control) and 3 noncognitive networks (primary visual, extrastriate visual, motor). Using linear and curvilinear mixed models, we used baseline connectivity in these networks to predict longitudinal changes in preclinical Alzheimer cognitive composite (PACC) performance, both alone and interacting with Aβ burden. Median neuropsychological follow-up was 3 years. Baseline connectivity in the default, salience, and control networks predicted longitudinal PACC decline, unlike connectivity in the dorsal attention and all noncognitive networks. Default, salience, and control network connectivity was also synergistic with Aβ burden in predicting decline, with combined higher Aβ and lower connectivity predicting the steepest curvilinear decline in PACC performance. In clinically normal older adults, lower functional connectivity predicted more rapid decline in PACC scores over time, particularly when coupled with increased Aβ burden. Among examined networks, default, salience, and control networks were the strongest predictors of rate of change in PACC scores, with the inflection point of greatest decline beyond the fourth year of follow-up. These results suggest that rs-fcMRI may be a useful predictor of early, AD-related cognitive decline in clinical research settings. © 2017 American Academy of Neurology.

The increase of the fertility of soils using the liquid organic fertilizers and fertilizers based on sugar-beet wastes.

Science.gov (United States)

Vyborova, Oxana

2010-05-01

The fertility of soil is a capacity for ensuring plants by water, nutrients, air and capacity for making optimal conditions for growth and development of plants. The result of it is a yield. The main characteristic of fertility of soil is maintenance of humus. The humus is important part of organic matter. The supporting of soil fertility is impossible by traditional methods. The amount of receiving mineral fertilizers in agriculture will not increase in future, because mineral fertilizers are very expensive. The mineral fertilizers don't influence on maintenance of total amount of humus in soil and improve the circulation of nutrients. Every hectare of fields have to receive no less than 8-10 tons of organic fertilizers, therefore we will have self-supporting balance of humus and the fertility of soils will be increasing. Consequently we are looking for new types of organic materials and we include them in modern agro technologies. One of them is an organomineral fertilizer (lignitic materials). The humic chemicals in the form of lignitic materials of natrium, potassium and ammonium are permitted for using them in agriculture at the beginning of 1984. The Department of agriculture in Russian Federation considered the problem of using humic chemicals and made a decision to use them on the fields of our country, because the lignitic materials can restore the fertility of our fields. The lignitic materials increase the amount of spore-forming bacteria, mold fungi and actinomycete. Therefore the organic decomposition occurs more strongly, the processes of humification increase the speed and the amount of humus rises in the soil. The new forming humus has a high biological activity and it improves chemical and physical soil properties. The addition of lignitic materials in soil activates different groups of microorganisms, which influence on mobilization of nutrients and transformation from potential to effective fertility. The inclusion of humic fertilizers improves

Household Fertilizers Use and Soil Fertility Management Practices ...

African Journals Online (AJOL)

Household Fertilizers Use and Soil Fertility Management Practices in Vegetable Crops Production: The Case of Central Rift Valley of Ethiopia. ... rate, which could leads to pollution of the environment from over dose application and from runoff in to the water bodies and leaching in to the ground water with economic loss.

Assessment of expected breeding values for fertility traits of Murrah buffaloes under subtropical climate

Directory of Open Access Journals (Sweden)

Soumya Dash

2015-03-01

Full Text Available Aim: The aim of the present study was to assess the influence of temperature and humidity prevalent under subtropical climate on the breeding values for fertility traits viz. service period (SP, pregnancy rate (PR and conception rate (CR of Murrah buffaloes in National Dairy Research Institute (NDRI herd. Materials and Methods: Fertility data on 1379 records of 581 Murrah buffaloes spread over four lactations and climatic parameters viz. dry bulb temperature and relative humidity (RH spanned over 20 years (1993-2012 were collected from NDRI and Central Soil and Salinity Research Institute, Karnal, India. Monthly average temperature humidity index (THI values were estimated. Threshold THI value affecting fertility traits was identified by fixed least-squares model analysis. Three zones of non-heat stress, heat stress and critical heat stress zones were developed in a year. The genetic parameters heritablility (h2 and repeatability (r of each fertility trait were estimated. Genetic evaluation of Murrah buffaloes was performed in each zone with respect to their expected breeding values (EBV for fertility traits. Results: Effect of THI was found significant (p<0.001 on all fertility traits with threshold THI value identified as 75. Based on THI values, a year was classified into three zones: Non heat stress zone(THI 56.71-73.21, HSZ (THI 75.39-81.60 and critical HSZ (THI 80.27-81.60. The EBVfor SP, PR, CR were estimated as 138.57 days, 0.362 and 69.02% in non-HSZ while in HSZ EBV were found as 139.62 days, 0.358 and 68.81%, respectively. EBV for SP was increased to 140.92 days and for PR and CR, it was declined to 0.357 and 68.71% in critical HSZ. Conclusion: The negative effect of THI was observed on EBV of fertility traits under the non-HSZ and critical HSZ Thus, the influence of THI should be adjusted before estimating the breeding values for fertility traits in Murrah buffaloes.

Increasing land sustainability and productivity through soil-fertility management in the West African Sudano-Sahelian zone

International Nuclear Information System (INIS)

Bationo, A.; Vanlauwe, B.; Kimetu, J.; Kihara, J.; Abdoulaye, M.S.; Adamou, A.; Tabo, R.; Koala, S.

2005-01-01

Food production has lagged behind population growth in most parts of the West African semi-arid tropics (WASAT). One of the reasons for low food production is decline in soil fertility as a consequence of continuous cropping without fertilization. As a result, there is a negative nutrient balance in most land-use systems in WASAT. The amount of nutrients leaving the soil, through crop uptake, leaching and erosion exceeds that returned through natural processes such as atmospheric deposition and biological nitrogen fixation or through additions of inorganic and organic fertilizers. Use of mineral fertilizers by many smallholder farmers remains low because of socio-economic constraints. Lack of adequate foreign exchange to import fertilizers, poor infrastructure and poor distribution mechanisms have hampered the use of inorganic fertilizers. Organic inputs such as manure, compost and crop residues are often proposed as alternatives to mineral fertilizers, however, it is important to recognize that in most cases the use of organic inputs is part of an internal flow of nutrients within the farm and does not add nutrient from outside the farm; also, quantities available are inadequate to meet nutrient needs over large areas because of limited availability, low nutrient content of the material, and high labour demands for processing and application. The beneficial effects of combined manure and inorganic nutrients on soil fertility have been repeatedly shown, yet there is need for more research on the establishment of the fertilizer equivalency of manures, in determining the optimum combination of these two plant nutrients and in taking into account the high variability in their quality. Such information is useful in formulating decision-support systems and in establishing simple guidelines for management and utilization of the resources. This paper highlights current research results on the management of nitrogen, phosphorus and organic matter and summarizes our

Utilization of /sup 15/N in the sequence of mineral fertilizer - forage - animal - slurry - forage

Energy Technology Data Exchange (ETDEWEB)

Peschke, H [Humboldt-Universitaet, Berlin (German Democratic Republic). Sektion Pflanzenproduktion

1981-12-01

After systematic application of /sup 15/N-ammonium nitrate, the change of the dinuclidic composition and /sup 15/N quantity was studied by isotope analysis of several open systems in the sequence mineral fertilizer - (soil) - forage - (animal) - slurry - (soil) - forage. The relative /sup 15/N isotope frequency of 50 atom% in the mineral fertilizer declined to 12.2 to 21.4 atom% in the forage (beet, oats, hay) and went down to 3.15 atom% in the slurry of a dairy cow fed on this forage. Silage maize manured with the slurry of the dairy cow only showed 1.98 atom %, green oats grown after the silage maize on the same area was found to have 0.45 atom%. The /sup 15/N quantity of 104.5 g N in the fertilizer gradually decreased to 41.6 g N in the forage, 30.5 g N in the slurry and 22.6 g N in the silage maize. The causes discussed are /sup 15/N isotope dilution as qualitative factor and productive and unproductive N losses as quantitative factors.

THE FAST DECLINING TYPE Ia SUPERNOVA 2003gs, AND EVIDENCE FOR A SIGNIFICANT DISPERSION IN NEAR-INFRARED ABSOLUTE MAGNITUDES OF FAST DECLINERS AT MAXIMUM LIGHT

International Nuclear Information System (INIS)

Krisciunas, Kevin; Marion, G. H.; Suntzeff, Nicholas B.

2009-01-01

We obtained optical photometry of SN 2003gs on 49 nights, from 2 to 494 days after T(B max ). We also obtained near-IR photometry on 21 nights. SN 2003gs was the first fast declining Type Ia SN that has been well observed since SN 1999by. While it was subluminous in optical bands compared to more slowly declining Type Ia SNe, it was not subluminous at maximum light in the near-IR bands. There appears to be a bimodal distribution in the near-IR absolute magnitudes of Type Ia SNe at maximum light. Those that peak in the near-IR after T(B max ) are subluminous in the all bands. Those that peak in the near-IR prior to T(B max ), such as SN 2003gs, have effectively the same near-IR absolute magnitudes at maximum light regardless of the decline rate Δm 15 (B). Near-IR spectral evidence suggests that opacities in the outer layers of SN 2003gs are reduced much earlier than for normal Type Ia SNe. That may allow γ rays that power the luminosity to escape more rapidly and accelerate the decline rate. This conclusion is consistent with the photometric behavior of SN 2003gs in the IR, which indicates a faster than normal decline from approximately normal peak brightness.

Declining resilience of ecosystem functions under biodiversity loss.

Science.gov (United States)

Oliver, Tom H; Isaac, Nick J B; August, Tom A; Woodcock, Ben A; Roy, David B; Bullock, James M

2015-12-08

The composition of species communities is changing rapidly through drivers such as habitat loss and climate change, with potentially serious consequences for the resilience of ecosystem functions on which humans depend. To assess such changes in resilience, we analyse trends in the frequency of species in Great Britain that provide key ecosystem functions--specifically decomposition, carbon sequestration, pollination, pest control and cultural values. For 4,424 species over four decades, there have been significant net declines among animal species that provide pollination, pest control and cultural values. Groups providing decomposition and carbon sequestration remain relatively stable, as fewer species are in decline and these are offset by large numbers of new arrivals into Great Britain. While there is general concern about degradation of a wide range of ecosystem functions, our results suggest actions should focus on particular functions for which there is evidence of substantial erosion of their resilience.

Low vitamin B-12 status and risk of cognitive decline in older adults

DEFF Research Database (Denmark)

Clarke, Robert; Birks, Jacqueline; Nexo, Ebba

2007-01-01

remained significant. CONCLUSIONS: Low vitamin B-12 status was associated with more rapid cognitive decline. Randomized trials are required to determine the relevance of vitamin B-12 supplementation for prevention of dementia. Udgivelsesdato: 2007-Nov......BACKGROUND: Elevated total homocysteine (tHcy) concentrations have been associated with cognitive impairment, but it is unclear whether low vitamin B-12 or folate status is responsible for cognitive decline. OBJECTIVE: We examined the associations of cognitive decline with vitamin B-12 and folate...... status in a longitudinal cohort study performed from 1993 to 2003 in Oxford, United Kingdom. DESIGN: Cognitive function was assessed with the Mini-Mental State Examination on >/=3 occasions during 10 y and related to serum concentrations of vitamin B-12, holotranscobalamin (holoTC), tHcy, methylmalonic...

PROTOPLANETARY DISK MASSES IN IC348: A RAPID DECLINE IN THE POPULATION OF SMALL DUST GRAINS AFTER 1 Myr

International Nuclear Information System (INIS)

Lee, Nicholas; Williams, Jonathan P.; Cieza, Lucas A.

2011-01-01

We present a 1.3 mm continuum survey of protoplanetary disks in the 2-3 Myr old cluster, IC348, with the Submillimeter Array. We observed 85 young stellar objects and detected 10 with 1.3 mm fluxes greater than 2 mJy. The brightest source is a young embedded protostar driving a molecular outflow. The other nine detections are dusty disks around optically visible stars. Our millimeter flux measurements translate into total disk masses ranging from 2 to 6 Jupiter masses. Each detected disk has strong mid-infrared emission in excess of the stellar photosphere and has Hα equivalent widths larger than the average in the cluster and indicative of ongoing gas accretion. The disk mass distribution, however, is shifted by about a factor of 20 to lower masses, compared to that in the ∼1 Myr old Taurus and Ophiuchus regions. These observations reveal the rapid decline in the number of small dust grains in disks with time and probably their concomitant growth beyond millimeter sizes. Moreover, if IC348 is to form planets in the same proportion as detected in the field, these faint millimeter detections may represent the best candidates in the cluster to study the progression from planetesimals to planets.

The impact of kin availability, parental religiosity, and nativity on fertility differentials in the late 19th-century United States.

Science.gov (United States)

Hacker, J David; Roberts, Evan

2017-12-01

Most quantitative research on fertility decline in the United States ignores the potential impact of cultural and familial factors. We rely on new complete-count data from the 1880 U.S. census to construct couple-level measures of nativity/ethnicity, religiosity, and kin availability. We include these measures with a comprehensive set of demographic, economic, and contextual variables in Poisson regression models of net marital fertility to assess their relative importance. We construct models with and without area fixed effects to control for unobserved heterogeneity. All else being equal, we find a strong impact of nativity on recent net marital fertility. Fertility differentials among second generation couples relative to the native-born white population of native parentage were in most cases less than half of the differential observed among first generation immigrants, suggesting greater assimilation to native-born American childbearing norms. Our measures of parental religiosity and familial propinquity indicated a more modest impact on marital fertility. Couples who chose biblical names for their children had approximately 3% more children than couples relying on secular names while the presence of a potential mother-in-law in a nearby households was associated with 2% more children. Overall, our results demonstrate the need for more inclusive models of fertility behavior that include cultural and familial covariates.

Fertility awareness and attitudes towards parenthood among Danish university college students

DEFF Research Database (Denmark)