Recent trends and components of change in fertility in Nepal

The objectives of this article are, first, to provide improved estimates of recent fertility levels and trends in Nepal and, second, to analyse the components of fertility change. The analysis is based on data from Nepal's 1996 and 2001 Demographic and Health Surveys. Total fertility rates (TFR) are derived by the own-children method. They incorporate additional adjustments to compensate for displacement of births, and they are compared with estimates derived by the birth-history method. Fertility is estimated not only for the whole country but also by urban/rural residence and by woman's education. The own-children estimates for the whole country indicate that the TFR declined from 4.96 to 4.69 births per woman between the 3-year period preceding the 1996 survey and the 3-year period preceding the 2001 survey. About three-quarters of the decline stems from reductions in age-specific marital fertility rates and about one-quarter from changes in age-specific proportions currently married. Further decomposition of the decline in marital fertility, as measured by births per currently married woman during the 5-year period before each survey, indicates that almost half of the decline in marital fertility is accounted for by changes in population composition by ecological region, development region, urban/rural residence, education, age at first cohabitation with husband, time elapsed since first cohabitation, number of living children at the start of the 5-year period and media exposure. With these variables controlled, another one-third of the decline is accounted for by increase in the proportion sterilized at the start of the 5-year period before each survey.     

A good man is hard to find: overseas migration and the decentered family in the Tongan Islands

The impact of widespread international labor migration on the family in Tonga is examined. The author describes how migration has affected gender and kinship relations. She also examines the ways in which church and state ideologies encourage the development of the nuclear family, while overseas labor migration creates a need to maintain extended support systems among family networks.     

Reproductive pattern in agrarian and immigrant receptor populations: a survey of El Ejido (SE Spain)

This paper deals with the fertility pattern of the El Ejido population, an agricultural Spanish community characterised by the rapid development of its modern agrarian economy. Consequently, the arrival of immigrants has sharply increased throughout the second half of the twentieth century, with important demographic consequences as well as reproductive changes. The analyses of the age-specific fertility rate (fx) and the total fertility rate (TFR) were used in order to describe the reproductive pattern of this population in 2000. The main characteristics were the following: a) Regarding the temporal change, an important decrease of fx has been observed in all age groups for the last twenty years, as a consequence of progressive birth control. However, the reproductive pattern has kept almost invariable and has been characterised by a maximum fertility at age group of 25-29 years old. b) Regarding the general Spanish fertility, the comparison of fx in both populations suggests a younger maternity in the agricultural population than in the national, the maximum fertility delayed to the 30-34 age group. c) Moreover, the El Ejido population showed a clear higher offspring per woman (TFR = 1.42) than the national (TFR = 1.24), according to the agrarian character of the El Ejido population. d) Finally, this greater reproductive level of El Ejido is also due to the arrival of women at fertile age, who come mainly from Africa, and above all from Morocco.     

Effect of nuptiality, contraception and breast-feeding on fertility in Bangladesh

The effects of marriage, contraception, and post-partum lactational infecundability on fertility in Bangladesh are assessed by applying Bongaarts' formula to survey data for the period 1975-1985. Marriage is universal and age at marriage is low. Breastfeeding is prolonged and has a pronounced effect on fertility. The fertility-reducing effect of contraception increased over the period through increased use of modern methods. The total fertility rate (TFR) declined by 24% from 1975 to 1985. This study shows that the 3 major proximate determinants cannot account completely for variation in national fertility levels.     

Trap catches of the small brown planthopper, <Emphasis Type="Italic">Laodelphax striatellus</Emphasis> (Fallén) (Hemiptera: Delphacidae), in northern Kyushu district,Japan in relation to weather conditions

Abstract  

The pattern of overseas immigration of Laodelphax striatellus (Fallén) into northern Kyushu district in relation to weather conditions was analyzed using trap catch data, weather data, and backward trajectory analysis. The investigation covered the period May 21 to June 10 of each year between 2000 and 2009. One peak trap catch was recorded on May 27–28, 2006 and was associated with strong westerly winds at 850 and 925 hPa levels to the south of a cold vortex that passed over the southern part of the Korean peninsula. The backward trajectory analysis suggested Jiangsu Province, China, as possible migration source. Another peak catch on June 5, 2008 has already been reported as an overseas migration from Jiangsu Province, China. This study revealed that a cold vortex passing the southern Korean peninsula was also associated with insect migration in 2008. Thus, there is evidence of at least 2 overseas migrations from Jiangsu Province, China, over a 10-year period that coincided with strong westerly winds in the lower atmosphere that were associated with cold vortices.     

Canadian fertility trends in perspective

This paper examines the broad movements of Canadian period and cohort fertility over the past 100 years, and compares them with corresponding trends in the US and other industrialized countries. The main movement in Canada was a decline in fertility extending from the 19th century to the present, interrupted in the 1940s and 1950s by a baby boom. Between 1871 and 1937 the total fertility rate (TFR) fell at about an average of 1.4% annually. The rate of fall in the US was similar, with the result that in the late 1930s the Canadian TFR was about 20% that of the US. The fertility boom that followed was steeper in the US than in Canada, and in the downswing that later followed, the rate of decline was similar in the 2 countries (3.4-4% annual average). But, the decline continued longer-- indeed still continues--in Canada, whereas the TFR in the US reached its lowest point in 1976. Moreover, the recent decline in fertility has been more severe in Canada than in almost any other industrialized country. The TFR relates to fertility in a single year and is highly sensitive to short-term changes in the timing of births. For the purposes of understanding and explaining long-term trends in fertility, the completed fertility rate (CFR) is a better index because it measures the ultimate family size of cohorts. Cohort fertility can be seen to fluctuate much less than does period fertility. In both the US and Canada, the peak cohorts, born in the early 1930s, had roughly the same completed fertility, and later cohorts continued to remain closely in step as the CFR fell sharply. In Canada the fall continues, though at a reduced rate, in the latest cohorts for which there is information. Apart from differences in amplitude, the dates of turning points and the shapes of the TFR and CFR curves of Canadian fertility are fairly similar. The long decline in cohort fertility is largely explained by the decrease in the proportions of families of 6 or more children. During the baby boom, for Catholics and non-Catholics alike, the proportion of ever-married women remaining childless fell by about 40%, the proportion having 2 children changed little, and the proportions having 3,4 and 5 children tended to increase substantially. The crucial difference between the 2 groups was in the proportions of women having 6 or more children. For non-Catholics, the proportion fell by over 4% from a high level. For non-Catholics, on the other hand, the proportion rose somewhat, though even after the rise, it was barely more than 1/2 the level to which the Catholic proportion had declined. Among Catholics, the effect of the massive decline in the proportion of women having 6 or more children was to swamp the effects of the increase in the proportions of women having 3, 4 and 5 children. The net effect was that fertility declined. Among non-Catholics, however, the comparable increases in the proportions of families of 3, 4 and 5 children, were not offset by any fall in the proportion of larger families, with the result that a baby boom occurred.     

Fertility and social class in a French village, 1901-75

Explanations of rural-urban fertility differentials have normally lain in assumptions about the traditionalist nature of rural, and especially agricultural, societies in contrast to the more rationalist and modern attitudes towards the family that exist in urban societies. This paper raises 2 objections to such an oversimplified view of rural-urban fertility differentials. The 1st is that rural fertility is assumed to have been relatively uncontrolled until the final stages of the demographic transition: the possibility of significant early control on fertility in rural areas is discounted. The 2nd is that this simplistic view of fertility differentials ignores the existence of social sub-groups within the rural population and assumes that all country-dwellers are members of an idealized rural society and behave, demographically, in a uniform fashion. The extent to which it is possible to recognize distinctive patterns of marriage and fertility within sub-groups of the rural population is examined by an analysis of the fertility experience of 294 females who lived in a single village in southern Normandy at some period between 1901 and 1975. Biographical details were obtained from an exhaustive analysis of census lists and the civil registration documents to attempt a family and household reconstitution. Other sources used include electoral registers and land-ownership records. The pattern of evolution of fertility in the village for the period considered is derived using Coale's demographic indices: indices of female proportions married, marital fertility, illegitmate fertility and overall fertility are derived by standardizing the population under study against the age-specific fertility schedules of a population believed to have natural fertiltity (the American Hutterites). Overall fertility has increased slightly through the 75-year period, being notably low at the star of the century, chiefly as a result of the high average age at 1st marrige of girls from owner-oc pying farm families. Changes in overall fertility through the century have partly resulted from changes in the proportionate contribution of the different sub-classes of the village as a whole, but the increased importance of owner-occupying farm households has been compensated by a similar increase in the importance of employees in nonagricultural activities who have the highest fertility levels of all. The explanations of these differentials in fertility between sub-classes of the local population appear to lie in the relationships of those classes to the labor market, and in the degree to which capital accumulation and inheritance act as a brake on early marriage and fertility within marriage.     

How big are educational and racial fertility differentials in the U.S.?

Using pooled data from the 1980, 1985, 1990 and 1995 CPS and 1988 and 1995 NSFG surveys, we show that shifts in fertility timing have occurred disproportionately for the more educated and for whites (compared to the less educated and to African Americans). Such timing shifts imply that the underlying period quantum of fertility is considerably higher for college-educated women and for whites than suggested by the standard total fertility rate. Applying the Bongaarts-Feeney model (1998), we decompose observed racial and educational differences in age-order-specific fertility rates and TFR into tempo and quantum components. We find that a modest part of educational differences and a substantial part of racial difference in period fertility can be attributed to differential changes in tempo. Analysis by race and education shows a clear interaction: higher fertility among African Americans is confined to the less educated.     

Mesenchymal Stromal Cells Support the Viability and Differentiation of Follicular Lymphoma-Infiltrating Follicular Helper T-Cells

The biology of follicular lymphoma (FL) is largely dictated by the immune-effector and stromal cells that comprise its tumor microenvironment. FL-infiltrating T-cell populations that are thought to be fundamental to FL biology are follicular helper T-cells (TFH), follicular regulatory T-cells (TFR), a recently described population that regulates TFH activity, and regulatory T-cells (Treg). These T-cell populations have dynamic interactions with mesenchymal stromal cells (MSCs) in the tumor microenvironment. Whereas MSCs have been shown to support FL B-cell and Treg viability, their effects on FL-infiltrating TFH and TFR cells have not been described. Herein we show that MSCs support the viability of FL-infiltrating TFH and TFR, as well as Tregs, in part through an IL-6-dependent mechanism. We further demonstrate that MSCs mediate TFH to TFR conversion by inducing the expression of FoxP3 in TFH cells, demonstrating for the first time that human TFR can be derived from TFH cells. Given that the balance of TFH and TFR populations likely dictate, in part, the biology of this disease, our data support the potential for targeting MSCs as a therapeutic strategy.     

Dynamic of marriage structure in three cities of Ukraine from 1960 to 1992

Marriage structure was studied in the city of Kiev and in two cities of the Sumy oblast, Shostka and Trostyanets. Ethnic affiliations and birthplaces of persons contracting marriage were analyzed as the main characteristics of population genetic diversity. The ethnic composition of persons contracting marriage and the proportions of mono- and interethnic marriages remained almost unchanged during one generation. The majority of the persons contracting marriage were Ukrainians (66-91%); among other ethnic groups, only Russians considerably contributed to ethnic diversity (up to 26%). During the period studied, coefficients of marital migration substantially decreased in Kiev (from 0.66-0.82 to 0.34) and Shostka (from 0.72 to 0.52) and changed only insignificantly in Trostyanets. Outbreeding was estimated based on the migration parameters, exogamy level, and marital migration distances. The outbreeding level in the Shostka population (100,000 people) was comparable with that for the considerably larger Kiev population (two million people); however, it was significantly higher than that for the Trostyanets population, the size of which was close to the size of the Shostka population. It is supposed that "migration stress" may unfavorably affect the adaptive genetic structure of the Shostka population.     

Climate change,demographic pressures and global sustainability

This article emphasizes the need for broader approaches for formulating policies for mitigating the effects of climate change especially in the contexts of agricultural decisions, and population health and migration. Constraints imposed by rapid population growth in developing countries for achievement of Sustainable Development Goals are discussed and evidence is presented on “unwanted” fertility from India. Second, comparisons are made for India during 2002–2016 for average well depths in 495 districts and terrestrial water storage anomalies assessed via GRACE satellites for 274 1° × 1° grids using estimated parameters from dynamic random effects models. Lastly, migration patterns especially of the highly educated from 39 sending countries to OECD countries during 2000–2010 are analyzed using dynamic random effects models and total fertility rates were significantly associated with higher migration rates for the highly educated. Implications of the empirical evidence for enhancing global sustainability are discussed.     

Fitness and extra-group reproduction in male Verreaux's sifaka: An analysis of reproductive success from 1989-1999

Adult males in social groups often compete with other male group members for access to adult females. In some primate species, males also seek mating opportunities in neighboring social groups. Such extra-group fertilizations (EGFs) provide an additional source of variation in male fitness. This additional component of fitness provided by EGFs must be incorporated into analyses that investigate sources of variation in male lifetime reproductive success. In this study, a model is analyzed in which male fitness over a 10-year sample period is decomposed into additive and multiplicative variance and covariance components. The data come from an ongoing study of a wild population of Verreaux's sifaka (Propithecus verreauxi verreauxi) located at Beza Mahafaly Special Reserve, Southwest Madagascar. Paternity and demographic data for 134 males are used to decompose male fitness into the following three multiplicative components: reproductive lifespan during sample period, fertility, and offspring survival. These multiplicative components are estimated for males reproducing within their resident groups plus (i.e., the additive portion) for males reproducing in neighboring social groups. The analysis shows that variation in fertility makes the largest contribution to variation in total fitness, followed by variation in amount of time spent in sample period (which is a proxy of total reproductive lifespan) and variation in offspring survival. EGFs contribute an important source of variation to male fitness, and numerous factors enhance the opportunities for EGFs in male sifaka. These include female choice, a high degree of home range overlap, and a limited mating season.     

Severe inbreeding depression in a wild wolf (Canis lupus) population

The difficulty of obtaining pedigrees for wild populations has hampered the possibility of demonstrating inbreeding depression in nature. In a small, naturally restored, wild population of grey wolves in Scandinavia, founded in 1983, we constructed a pedigree for 24 of the 28 breeding pairs established in the period 1983-2002. Ancestry for the breeding animals was determined through a combination of field data (snow tracking and radio telemetry) and DNA microsatellite analysis. The population was founded by only three individuals. The inbreeding coefficient F varied between 0.00 and 0.41 for wolves born during the study period. The number of surviving pups per litter during their first winter after birth was strongly correlated with inbreeding coefficients of pups (R2=0.39, p<0.001). This inbreeding depression was recalculated to match standard estimates of lethal equivalents (2B), corresponding to 6.04 (2.58-9.48, 95% CI) litter-size-reducing equivalents in this wolf population.     

Components and Public Health Impact of Population Growth in the Arab World

The Arab world, which consists of the 22 member states of the Arab League, is undergoing a rapid transition in demographics, including fertility, mortality, and migration. Comprising a distinctive geographic region spread across West Asia and North East Africa and unified by the Arabic language, these states share common values and characteristics despite having diverse economic and political conditions. The demographic lag (high fertility and low mortality) that characterizes the Arab world is unique, but the present trend of declining fertility, combined with the relatively low mortality, brings about significant changes in its population size. This research aimed to: (i) assess the population growth in the Arab world over 3 time periods, (ii) explore its components, and (iii) understand its public health impact. Data from the International Data Base (IDB) of the U.S. Census Bureau for 3 time periods (1992, 2002, and 2012) in 21 countries of the Arab world were analyzed by dividing them into four geographic sectors, namely, the Gulf Cooperation Council (GCC), West Asia, Maghreb, and the Nile Valley African Horn. The population of the Arab world has grown considerably due to both natural growth and migration. The immigration is pronounced, especially into resource-intensive GCC nations, not only from East Asian and Central African countries but also from resource-thrifty (limited-resource) Arab nations. The migrations within, as well as outside, the Arab world reveal an interesting demographic phenomenon that requires further research: migration flows and trends. However, the transformations in public health statistics related to mortality—the impact of demographic changes—depict a new era in the Arab world.     

Fitness effects of X chromosome drive in the stalk-eyed fly, Cyrtodiopsis dalmanni

Sex-ratio (SR) males produce predominantly female progeny because most Y chromosome sperm are rendered nonfunctional. The resulting transmission advantage of XSR chromosomes should eventually cause population extinction unless segregation distortion is masked by suppressors or balanced by selection. By screening male stalk-eyed flies, Cyrtodiopsis dalmanni, for brood sex ratio we found unique SR alleles at three X-linked microsatellite loci and used them to determine if SR persists as a balanced polymorphism. We found that XSR/XST females produced more offspring than other genotypes and that SR males had lower sperm precedence and exhibited lower fertility when mating eight females in 24 h. Adult survival was independent of SR genotype but positively correlated with eye span. We infer that the SR polymorphism is likely maintained by a combination of weak overdominance for female fecundity and frequency dependent selection acting on male fertility. Our discovery of two SR haplotypes in the same population in a 10-year period further suggests that this SR polymorphism may be evolving rapidly.     

渭北塬区不同龄苹果园土壤微生物空间分布特征

以渭北塬区塬面5、10、15和20龄苹果园为对象,距树干1.0、1.5、2.0 m处用土钻法分层采集0—30 cm土样,稀释平板法测定土壤微生物数量,平行测定土壤有机碳、总氮和总磷,分析不同龄果园土壤微生物的空间分布状况及其与土壤碳、氮、磷的关系。结果表明:土壤真菌数量随树龄增大而增加,龄间差异显著(P0.05);与对照农田相比,各龄果园放线菌数量及5龄和20龄果园细菌数量偏低,10龄和15龄果园细菌数量偏高;各龄果园土壤真菌、细菌和放线菌数量均随深度增加而减小。就相同深度土层而言,真菌数量随果园年限增大而增加,细菌则以10龄和15龄果园较多,同深度土层的放线菌龄间差异随深度增加而减小。在沿树干向外的径向水平方向上,真菌数量随果园年限的增加相应增多;10龄和15龄果园土壤细菌和放线菌高于5龄果园和20龄果园。5龄果园土壤总氮有沿树干向外、沿表层向下逐步降低的趋势,果园从5龄经10龄到15龄,其"高氮点"则逐步向外、向下移动。塬区果园土壤C∶N比偏低。     

Indirect Estimates of Total Fertility Rate Using Child Woman/Ratio: A Comparison with the Bogue-Palmore Method

Indirect estimation methodologies of the total fertility rate (TFR) have a long history within demography and have provided important techniques applied demographers can use when data is sparse or lacking. However new methodologies for approximating the total fertility rate have not been proposed in nearly 30 years. This study presents a novel method for indirectly approximating the total fertility rate using an algebraic rearrangement of the general fertility rate (GFR) through the known relationship between GFR and TFR. It then compares the proposed method to the well-known Bogue-Palmore method. These methods are compared in 196 countries and include overall errors as well as characteristics of the countries that contribute to fertility behavior. Additionally, these methods were compared geographically to find any geographical patterns. We find this novel method is not only simpler than the Bogue-Palmore method, requiring fewer data inputs, but also has reduced algebraic and absolute errors when compared with the Bogue-Palmore method and specifically outperforms the Bogue-Palmore method in developing countries. We find that our novel method may be useful estimation procedure for demographers.     

A Population Estimate for Golden Eagles in the Western United States

ABSTRACT Researchers have suggested golden eagle (Aquila chrysaetos) populations may be declining in portions of their range. However, there are few baseline data describing golden eagle populations across their range in the western United States. We used aerial line transect distance methodology with a double-observer modification to estimate golden eagle population numbers in 4 bird conservation regions of the western United States. We conducted surveys from 16 August to 8 September 2003, after most golden eagles had fledged and before fall migration. The goal of our sampling strategy was to provide >80% power (α = 0.1) to detect an annual rate of total population change >3% per year over a 20-year period. We observed 172 golden eagles across 148 transects and estimated 27,392 golden eagles (90% CI: 21,352-35,140) occurred in the study area during the late summer and early fall of 2003. Following the surveys, we used Monte Carlo simulation to determine the statistical power to detect trends in the golden eagle populations if yearly surveys were continued over a 20-year monitoring period. The simulation indicated the desired power could be achieved under the current methodology and sample size. The methods utilized in this study can be implemented for other raptor species when population estimates that include nonbreeding members of a population are needed. The results of this study can be utilized by professionals to help manage golden eagle populations and to develop conservation strategies.     

A relative cohort size forecasting model of Canadian total live births

Easterlin and Condran suggest that Canadian fertility is dictated by a relative cohort size (or relative income) model of fertility which points to a resurgence of fertility rather than a decline in the next 2 decades. Samuelson (1976) formalized Easterlin's model and shows that if the Easterlin effect is sufficiently strong, cycles in fertility will result. Ahlburg (1983) demonstrates that this model fits the US postwar fertility data very well and predicts the revival of fertility in the 1980s and 1990s. This model is applied to Canadian data as a check on Easterlin and Condran's earlier analysis and to determine whether the model also predicts a revival of Canadian fertility. According to the model, increases in the size of a birth cohort relative to preceding cohorts reduce that cohort's income relative to that of smaller cohorts and consequently reduce the fertility of the large cohort. In this manner, the size of a particular cohort is a function of the size of previous birth cohorts. The model assumes that immigration is zero, or, at least, relatively small. From the statistics, it does not appear that emigration or immigration was sufficiently large to alter significantly the age-structure of the Canadian population. Additionally, foreign-born women have much lower fertility than native-born women, particularly among postwar immigrants. Thus, the model outlined may be a useful approximation to the Canadian experience. Table 1 reports the results of estimating the model for Canadian data for the 1941-79 period. The results are consistent with the relative cohort size model that is outlined. The variables were correctly signed and significant at the 0.05 level in 1-tailed tests. The overall equation was significant at the 0.91 level. The forecasts with 20-year lags from the relative cohort model lie between the low and medium forecasts of Denton et al. until the end of this decade and between the medium and high forecast for the remainder of the 20th century. The model based on 25-year generational lags predicts 20% fewer births in the year 2000 than does the basic model, although it predicts births to increase significantly relative to the levels of the early 1960s. Policy decisions based on the unchallenged assumption of a continuance of low fertility may be ill-advised.     

Assessing moth migration and population structuring in Helicoverpa armigera (Lepidoptera: Noctuidae) at the regional scale: example from the Darling Downs, Australia

Analysis of gene flow and migration of Helicoverpa armigera (Hübner) in a major cropping region of Australia identified substantial genetic structuring, migration events, and significant population genotype changes over the 38-mo sample period from November 1999 to January 2003. Five highly variable microsatellite markers were used to analyze 916 individuals from 77 collections across 10 localities in the Darling Downs. The molecular data indicate that in some years (e.g., April 2002-March 2003), low levels of H. armigera migration and high differentiation between populations occurred, whereas in other years (e.g., April 2001-March 2002), there were higher levels of adult moth movement resulting in little local structuring of populations. Analysis of populations in other Australian cropping regions provided insight into the quantity and direction of immigration of H. armigera adults into the Darling Downs growing region of Australia. These data provide evidence adult moth movement differs from season to season, highlighting the importance of studies in groups such as the Lepidoptera extending over consecutive years, because short-term sampling may be misleading when population dynamics and migration change so significantly. This research demonstrates the importance of maintaining a coordinated insecticide resistance management strategy, because in some years H. armigera populations may be independent within a region and thus significantly influenced by local management practices; however, periods with high migration will occur and resistance may rapidly spread.