The distribution of physiotherapists in ontario: understanding the market drivers

PURPOSE

To understand the factors that affect the distribution of physiotherapists in Ontario by examining three potential influences in the multi-payer physiotherapy (PT) market: population need, critical mass (related to academic health science centres [AHSCs]), and market forces.

METHODS

Physiotherapist density and distribution were calculated from 2003 and 2005 College of Physiotherapists of Ontario registration data. Physiotherapists' workplaces were classified as not-for-profit (NFP) hospitals, other NFP, or for-profit (FP), and their locations were classified by census division (CD) types (cities and counties).

RESULTS

Physiotherapist density varied significantly and distribution was neither uniformly responsive to population need, nor driven primarily by market forces. The largest factor was an AHSC in a CD; physiotherapists locate disproportionately in NFP hospitals in AHSCs rather than in the growing FP sector.

CONCLUSIONS

While some patterns can be discerned in the distribution and densities of physiotherapists across Ontario, further work needs to be done to identify why population need and market forces appear to be less influential, and why CDs with AHSCs are so attractive to physiotherapists. With this additional information, it may be possible to identify ways to influence uneven distribution in the future.

Climate warming alters effects of management on population viability of threatened species: results from a 30-year experimental study on a rare orchid

Climate change is expected to influence the viability of populations both directly and indirectly, via species interactions. The effects of large-scale climate change are also likely to interact with local habitat conditions. Management actions designed to preserve threatened species therefore need to adapt both to the prevailing climate and local conditions. Yet, few studies have separated the direct and indirect effects of climatic variables on the viability of local populations and discussed the implications for optimal management. We used 30 years of demographic data to estimate the simultaneous effects of management practice and among-year variation in four climatic variables on individual survival, growth and fecundity in one coastal and one inland population of the perennial orchid Dactylorhiza lapponica in Norway. Current management, mowing, is expected to reduce competitive interactions. Statistical models of how climate and management practice influenced vital rates were incorporated into matrix population models to quantify effects on population growth rate. Effects of climate differed between mown and control plots in both populations. In particular, population growth rate increased more strongly with summer temperature in mown plots than in control plots. Population growth rate declined with spring temperature in the inland population, and with precipitation in the coastal population, and the decline was stronger in control plots in both populations. These results illustrate that both direct and indirect effects of climate change are important for population viability and that net effects depend both on local abiotic conditions and on biotic conditions in terms of management practice and intensity of competition. The results also show that effects of management practices influencing competitive interactions can strongly depend on climatic factors. We conclude that interactions between climate and management should be considered to reliably predict future population viability and optimize conservation actions.

Distributions and habitat associations of the bridled monocle bream Scolopsis bilineatus (Nemipteridae): a demographic approach

This study focussed on the demography and ecology of Scolopsis bilineatus at three locations on the Great Barrier Reef: the Lizard Island Group, Orpheus Island and One Tree Island. Scolopsis bilineatus lived for up to 16 years and had four distinct life-history stages, which varied in their distribution patterns, habitat use and reproductive behaviour. Pre-maturational sex change occurred whereby all males were derived from immature females, and males grew faster and larger than females. Small females and larger males generally formed pairs, which influenced their spatial distributions at small scales. Distributions of S. bilineatus were influenced by depth and exposure within reefs, particularly for juveniles, and most fish were found in shallow, sheltered habitats. Abundance was influenced by benthic cover, and was higher in areas of high coral cover and low where algae were abundant. Habitat associations were stronger at the microhabitat scale, and shelter sites were important for adults. Ontogenetic changes in microhabitat associations were found: juveniles occupied sand and rubble, and adults occupied shelters such as caves and overhangs. Adults showed site fidelity for shelter sites over a period of 4 days and returned to specific shelter sites repeatedly. These findings illustrate the importance of understanding the spatial ecology and habitat use of coral reef fishes, particularly with reference to size-based changes within species.

Factors influencing ascertainment bias of microsatellite allele sizes: impact on estimates of mutation rates

Microsatellite loci play an important role as markers for identification, disease gene mapping, and evolutionary studies. Mutation rate, which is of fundamental importance, can be obtained from interspecies comparisons, which, however, are subject to ascertainment bias. This bias arises, for example, when a locus is selected on the basis of its large allele size in one species (cognate species 1), in which it is first discovered. This bias is reflected in average allele length in any noncognate species 2 being smaller than that in species 1. This phenomenon was observed in various pairs of species, including comparisons of allele sizes in human and chimpanzee. Various mechanisms were proposed to explain observed differences in mean allele lengths between two species. Here, we examine the framework of a single-step asymmetric and unrestricted stepwise mutation model with genetic drift. Analysis is based on coalescent theory. Analytical results are confirmed by simulations using the simuPOP software. The mechanism of ascertainment bias in this model is a tighter correlation of allele sizes within a cognate species 1 than of allele sizes in two different species 1 and 2. We present computations of the expected average allele size difference, given the mutation rate, population sizes of species 1 and 2, time of separation of species 1 and 2, and the age of the allele. We show that when the past demographic histories of the cognate and noncognate taxa are different, the rate and directionality of mutations affect the allele sizes in the two taxa differently from the simple effect of ascertainment bias. This effect may exaggerate or reverse the effect of difference in mutation rates. We reanalyze literature data, which indicate that despite the bias, the microsatellite mutation rate estimate in the ancestral population is consistently greater than that in either human or chimpanzee and the mutation rate estimate in human exceeds or equals that in chimpanzee with the rate of allele length expansion in human being greater than that in chimpanzee. We also demonstrate that population bottlenecks and expansions in the recent human history have little impact on our conclusions.

Birth cohort effects on abdominal obesity in the United States: the Silent Generation, Baby Boomers and Generation X

BACKGROUND

Abdominal obesity predicts a wide range of adverse health outcomes. Over the past several decades, prevalence of abdominal obesity has increased markedly in industrialized countries like the United States No previous analyses, however, have evaluated whether there are birth cohort effects for abdominal obesity. Estimating cohort effects is necessary to forecast future health trends and understand the past population-level trends.

METHODS

This analysis evaluated whether there were birth cohort effects for abdominal obesity for the Silent Generation (born 1925-1945), children of the Great Depression; Baby Boomers (born 1946-1964); or Generation X (born 1965-1980). Cohort effects for prevalence of abdominal obesity were estimated using the median polish method with data collected from the National Health and Nutrition Examination Survey (NHANES) between 1988 and 2008. Respondents were aged 20-74 years.

RESULTS

After taking into account age effects and ubiquitous secular changes, the Silent Generation and Generation X had higher cohort-specific prevalence of abdominal obesity than the Baby Boomers. Effects were more pronounced in women than men.

CONCLUSIONS

This work presents a novel finding: evidence that the birth cohorts of the post-World War II Baby Boom appeared to have uniquely low cohort effects on abdominal obesity. The growing prosperity of the post-World War II US may have exposed the baby-boom generation to lower levels of psychosocial and socioeconomic stress than the previous or subsequent generations. By identifying factors associated with the Baby Boomers' low cohort-specific sensitivity to the obesogenic environment, the obesity prevention community can identify early-life factors that can protect future generations from excess weight gain.

Phenological overlap of interacting species in a changing climate: an assessment of available approaches

Concern regarding the biological effects of climate change has led to a recent surge in research to understand the consequences of phenological change for species interactions. This rapidly expanding research program is centered on three lines of inquiry: (1) how the phenological overlap of interacting species is changing, (2) why the phenological overlap of interacting species is changing, and (3) how the phenological overlap of interacting species will change under future climate scenarios. We synthesize the widely disparate approaches currently being used to investigate these questions: (1) interpretation of long-term phenological data, (2) field observations, (3) experimental manipulations, (4) simulations and nonmechanistic models, and (5) mechanistic models. We present a conceptual framework for selecting approaches that are best matched to the question of interest. We weigh the merits and limitations of each approach, survey the recent literature from diverse systems to quantify their use, and characterize the types of interactions being studied by each of them. We highlight the value of combining approaches and the importance of long-term data for establishing a baseline of phenological synchrony. Future work that scales up from pairwise species interactions to communities and ecosystems, emphasizing the use of predictive approaches, will be particularly valuable for reaching a broader understanding of the complex effects of climate change on the phenological overlap of interacting species. It will also be important to study a broader range of interactions: to date, most of the research on climate-induced phenological shifts has focused on terrestrial pairwise resource–consumer interactions, especially those between plants and insects.

Rural women veterans demographic report: defining VA users' health and health care access in rural areas

PURPOSE

While many women choose to live in rural areas after retiring from active military duty, a paucity of studies examine rural women veterans' health care needs. This report is the first of its kind to describe the population demographics and health care utilization of rural female veteran patients enrolled in the Department of Veterans Affairs (VA).

METHODS

Using the National Patient Care Datasets (n = 327,785), we ran adjusted regression analyses to examine service utilization between (1) urban and rural and (2) urban and highly rural women veterans.

FINDINGS

Rural and highly rural women veterans were older and more likely to be married than their urban counterparts. Diagnostic rates were generally similar between groups for several mental health disorders, hypertension, and diabetes, with the exception of nonposttraumatic stress anxiety that was significantly lower for highly rural women veterans. Rural and highly rural women veterans were less likely to present to the VA for women's specific care than urban women veterans; highly rural women veterans were less likely to present for mental health care compared to urban women veterans. Among the users of primary care, mental health, women's specific, and all outpatient services, patients' annual utilization rates were similar.

CONCLUSIONS

Improved service options for women's specific care and mental health visits may help rural women veterans access care. Telehealth technologies and increased outreach, perhaps peer-based, should be considered. Other recommendations for VA policy and planning include increasing caregiver support options, providing consistency for mental health services, and revising medical encounter coding procedures.

Demographic patterns of a widespread long-lived tree are associated with rainfall and disturbances along rainfall gradients in SE Australia

Predicting species distributions with changing climate has often relied on climatic variables, but increasingly there is recognition that disturbance regimes should also be included in distribution models. We examined how changes in rainfall and disturbances along climatic gradients determined demographic patterns in a widespread and long-lived tree species, Callitris glaucophylla in SE Australia. We examined recruitment since 1950 in relation to annual (200-600 mm) and seasonal (summer, uniform, winter) rainfall gradients, edaphic factors (topography), and disturbance regimes (vertebrate grazing [tenure and species], fire). A switch from recruitment success to failure occurred at 405 mm mean annual rainfall, coincident with a change in grazing regime. Recruitment was lowest on farms with rabbits below 405 mm rainfall (mean = 0-0.89 cohorts) and highest on less-disturbed tenures with no rabbits above 405 mm rainfall (mean = 3.25 cohorts). Moderate levels of recruitment occurred where farms had no rabbits or less disturbed tenures had rabbits above and below 405 mm rainfall (mean = 1.71-1.77 cohorts). These results show that low annual rainfall and high levels of introduced grazing has led to aging, contracting populations, while higher annual rainfall with low levels of grazing has led to younger, expanding populations. This study demonstrates how demographic patterns vary with rainfall and spatial variations in disturbances, which are linked in complex ways to climatic gradients. Predicting changes in tree distribution with climate change requires knowledge of how rainfall and key disturbances (tenure, vertebrate grazing) will shift along climatic gradients.

Clinical, sociodemographic, and service provider determinants of guideline concordant colorectal cancer care for Appalachian residents

BACKGROUND

Colorectal cancer represents a significant cause of morbidity and mortality, particularly in Appalachia where high mortality from colorectal cancer is more prevalent. Adherence to treatment guidelines leads to improved survival. This paper examines determinants of guideline concordance for colorectal cancer.

METHODS

Colorectal cancer patients diagnosed in 2006-2008 from 4 cancer registries (Kentucky, Ohio, Pennsylvania, and North Carolina) were linked to Medicare claims (2005-2009). Final sample size after exclusions was 2,932 stage I-III colon, and 184 stage III rectal cancer patients. The 3 measures of guideline concordance include adjuvant chemotherapy (stage III colon cancer, <80 years), ≥12 lymph nodes assessed (resected stage I-III colon cancer), and radiation therapy (stage III rectal cancer, <80 years). Bivariate and multivariate analyses with clinical, sociodemographic, and service provider covariates were estimated for each of the measures.

RESULTS

Rates of chemotherapy, lymph node assessment, and radiation were 62.9%, 66.3%, and 56.0%, respectively. Older patients had lower rates of chemotherapy and radiation. Five comorbidities were significantly associated with lower concordance in the bivariate analyses: myocardial infarction, congestive heart failure, respiratory diseases, dementia with chemotherapy, and diabetes with adequate lymph node assessment. Patients treated by hospitals with no Commission on Cancer (COC) designation or lower surgical volumes had lower odds of adequate lymph node assessment.

CONCLUSIONS

Clinical, sociodemographic, and service provider characteristics are significant determinants of the variation in guideline concordance rates of 3 colorectal cancer measures.

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

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

Health and society in Chukotka: an overview

This study provides a historical overview of the changes in the socio-economic and health status of the population of Chukotka, from the Soviet to the post-Soviet period, with special attention paid to the circumstances of indigenous people. Past health studies in Chukotka are reviewed and key demographic and health indicator data presented.

Since the 1990s, Chukotka's population has shrunk to a third of its former size due to emigration of non-indigenous and mostly younger people, with a corresponding increase in the mortality rate due to aging of the population. However, the indigenous population has remained stable. Among the most important causes of mortality are injuries. The living conditions of indigenous people continue to be a cause of concern, beset by high rates of poverty, unemployment, alcoholism, suicide and a variety of infectious diseases, such as tuberculosis and sexually transmitted infections. The economy, general infrastructure and health care system of Chukotka have been considerably improved by the Abramovich administration in the 2000s.

Demographic factors shaped diversity in the two gene pools of wild common bean Phaseolus vulgaris L

Wild common bean (Phaseolus vulgaris L.) is distributed throughout the Americas from Mexico to northern Argentina. Within this range, the species is divided into two gene pools (Andean and Middle American) along a latitudinal gradient. The diversity of 24 wild common bean genotypes from throughout the geographic range of the species was described by using sequence data from 13 loci. An isolation-migration model was evaluated using a coalescent analysis to estimate multiple demographic parameters. Using a Bayesian approach, Andean and Middle American subpopulations with high percentage of parentages were observed. Over all loci, the Middle American gene pool was more diverse than the Andean gene pool (π(sil)=0.0089 vs 0.0068). The two subpopulations were strongly genetically differentiated over all loci (F(st)=0.29). It is estimated that the two current wild gene pools diverged from a common ancestor ∼111 000 years ago. Subsequently, each gene pool underwent a bottleneck immediately after divergence and lasted ∼40 000 years. The Middle American bottleneck population size was ∼46% of the ancestral population size, whereas the Andean was 26%. Continuous asymmetric gene flow was detected between the two gene pools with a larger number of migrants entering Middle American gene pool from the Andean gene pool. These results suggest that because of the complex population structure associated with the ancestral divergence, subsequent bottlenecks in each gene pool, gene pool-specific domestication and intense selection within each gene pool by breeders; association mapping would best be practised within each common bean gene pool.

Resource transfers and evolution: helpful offspring and sex allocation

In some vertebrates, offspring help their parents produce additional offspring. Often individuals of one sex are more likely to become "helpers at the nest". We analyze how such sex-biased offspring helping can influence sex-ratio evolution. It is essential to account for age-structure because the sex ratios of early broods influence how much help is available for later broods; previous authors have not correctly accounted for this fact. When each female produces the same sex ratio in all broods (as assumed in all previous analyses of sex-biased helping), the optimal investment strategy is biased towards the more-helpful sex. When a female has facultative control over the sex ratio in each brood and each helper of a given sex increases the resource available for offspring production by a fixed amount, the optimal strategy is to produce only the more-helpful sex in early broods and only the less-helpful sex in later broods. When there are nonlinear returns from helping, i.e., each helper increases the amount of resource available for reproduction by an amount dependent upon the number of helpers, the optimal strategy is to maximize resource accrual from helping in early broods (which may involve the production of both sexes) and then switch to the exclusive production of the less-helpful sex in later broods. The population sex ratio is biased towards the more-helpful sex regardless of whether the sex ratio is fixed or age-dependent. When fitness returns from helping exhibit environmental patchiness, females are selected to produce only males on some patches and only females on others, and the population sex ratio may be biased in either direction. We discuss our results in light of empirical information on offspring helping, and we show via meta-analysis that there is no support for the claim of Griffin et al. [Griffin, A.S., Sheldon, B.C., West, S.A., 2005. Cooperative breeders adjust offspring sex ratios to produce helpful helpers. Amer. Nat. 166, 628-632] that parents produce more of the helpful sex when that sex is rare or absent.

Ecological and demographic correlates of helping behaviour in a cooperatively breeding bird

The evolution of cooperation is a persistent problem for evolutionary biologists. In particular, understanding of the factors that promote the expression of helping behaviour in cooperatively breeding species remains weak, presumably because of the diverse nature of ecological and demographic drivers that promote sociality. In this study, we use data from a long-term study of a facultative cooperative breeder, the long-tailed tit Aegithalos caudatus, to investigate the factors influencing annual variation in helping behaviour. Long-tailed tits exhibit redirected helping in which failed breeders may become helpers, usually at a relative's nest; thus, helping is hypothesised to be associated with causes of nest failure and opportunities to renest or help. We tested predictions regarding the relationship between annual measures of cooperative behaviour and four explanatory variables: nest predation rate, length of the breeding season, population-level relatedness and population density. We found that the degree of helping was determined principally by two factors that constrain successful independent reproduction. First, as predicted, cooperative behaviour peaked at intermediate levels of nest predation, when there are both failed breeders (i.e. potential helpers) and active nests (i.e. potential recipients) available. Second, there were more helpers in shorter breeding seasons when opportunities for renesting by failed breeders are more limited. These are novel drivers of helping behaviour in avian cooperative breeding systems, and this study illustrates the difficulty of identifying common ecological or demographic factors underlying the evolution of such systems.

Estimating the extent of household contact misclassification with index cases of disease in longitudinal studies using a stochastic simulation model

Background

Household contact with an index case of an infectious disease is a known risk factor for infection transmission. However, such contact may be underestimated due to the dynamic nature of households, particularly in longitudinal studies. Such studies generally begin with contact defined at a single point in time (‘snap-shot’), leading to contact misclassification for some individuals who actually experienced contact before and after the snapshot.

Objective

To quantify contact misclassification with index cases of disease in households.

Methods

Historical data of 112,026 individuals from 17,889 households from an epidemiological study on leprosy in northern Malawi were used. Individuals were interviewed in the early 1980s and followed up over 5 years. It was possible to trace whether individuals died, changed household within the area, or moved out of the area between the two surveys.

Using a 10% sample of households as the starting population and parameters for demographic and household changes over 5 years, the extent of contact misclassification was estimated through a simulation model of household dynamics, which traced contact with index cases in households over time. The model thereafter compared initial contact status and ‘true’ contact status generated from simulations.

Results

The starting population had 11,401 individuals, 52% female, and 224 (2%) leprosy index cases. Eleven percent of the households had at least one index case resident and 10% (1, 177) of non-case individuals were initial contacts. Sensitivity of initial contact status ranged from 0.52 to 0.74 and varied by age and sex. Sensitivity was low in those aged 20–29 and under 5 years but high in 5- to 14-year-olds. By gender, there were no differences among those aged under 5; females had lower sensitivity among those aged under 20 and higher for those above 30, respectively. Sensitivity was also low in simulations of long incubation periods.

Conclusion

This work demonstrates the implications of changes in households on household contact-associated disease spread, particularly for long durations of follow-up and infections with long incubation periods where earlier unobserved contact is critical.

Integrating oxidative ecology into conservation physiology

Ecologists have recently shown great interest in using physiological markers as indicators of the health of animal populations. In this context, the measurement of markers of oxidative balance, such as antioxidant defences and oxidative damage, may be a valuable tool. Indeed, at the individual level, antioxidant defences are positively associated with fertility and survival probability, while elevated oxidative damage during reproduction or growth may negatively affect recruitment and survival. Therefore, variation in oxidative balance is likely to influence demographic processes. This suggests that conservationists may be able to use oxidative markers to monitor population health. Yet, the connection between these markers and demographic parameters first needs to be established. We present here preliminary results obtained in colonies of breeding Gentoo (Pygoscelis papua) and Adélie penguins (Pygoscelis adeliae), showing that antioxidant defences strongly reflect population trends. However, population trend was not related to oxidative damage. This suggests that in the context of the emerging field of conservation physiology, antioxidant defences may represent a key parameter to monitor population health. We therefore exhort other research teams to assess the generality of this finding in other biological models, especially in species of conservation concern.

Determinants of the demand for using preventive medical care among adults in penang, malaysia

BACKGROUND

In light of the fact that chronic diseases were becoming more prevalent recently, the primary objective of the study was to examine the socio-demographic, health, and lifestyle determinants of the use of preventive medical care in Penang, Malaysia.

METHODS

The study used the primary survey data in Penang which had a total of 398 respondents. Respondents were chosen based on convenient sampling, and the survey was carried out in various locations in Penang. During the survey, the designed questionnaires were distributed for self-administration by the respondents between August and October, 2010. The binary logistic regression model was employed for statistical analysis.

RESULTS

Socio-demographic and health factors like income, marital status, education, history of serious family illnesses and self-perceived health status were statistically significant in affecting the likelihood of using preventive medical care. Specifically, being married (OR: 1.94; 95% CI: 1.13, 3.32), the presence of a history of serious family illnesses (OR: 2.14; 95% CI: 1.37, 3.36), having high income (OR: 8.71; 95% CI: 1.03, 73.59) and self-perceived poor health status (OR: 4.78; 95% CI: 1.09, 21.00) were positively related with using preventive medical care. However, having low educational background (OR: 0.23; 95% CI: 0.06, 0.95) were inversely related to the probability of using such medical care.

CONCLUSION

In view of the findings, the individuals' socio-demographic and health profiles were suggested to be given attention by the public health authorities if the goals of increasing the use of preventive medical care in the community were to be achieved.

Demographic inference reveals African and European admixture in the North American Drosophila melanogaster population

Drosophila melanogaster spread from sub-Saharan Africa to the rest of the world colonizing new environments. Here, we modeled the joint demography of African (Zimbabwe), European (The Netherlands), and North American (North Carolina) populations using an approximate Bayesian computation (ABC) approach. By testing different models (including scenarios with continuous migration), we found that admixture between Africa and Europe most likely generated the North American population, with an estimated proportion of African ancestry of 15%. We also revisited the demography of the ancestral population (Africa) and found-in contrast to previous work-that a bottleneck fits the history of the population of Zimbabwe better than expansion. Finally, we compared the site-frequency spectrum of the ancestral population to analytical predictions under the estimated bottleneck model.

Investigation the quality of life and its relation with clinical and demographic characteristics in women with breast cancer under chemotherapy

Background:

This study was performed to examine quality of life's dimensions and its relationship with some clinical and demographic characteristics on women with breast cancer under chemotherapy referred to the oncology hospital, Isfahan University of medical sciences, Iran.

Methods:

This Cross sectional study was conducted among 330 breast cancer patients with simple sampling methodology. Data collection instrument included a questionnaire contains 2 parts (clinical and demographic characteristics information and version 2.0 of the SF-36 questionnaire (the international version). The data were analyzed with 99% confidence by carried out using SPSS₁₈ with using descriptive and analytic statistics.

Results:

The majority of subjects’ quality of life was moderate (53.93%). there was a statistically significant relationship between quality of life among breast cancer patients with chemotherapy sessions (P < 0.05, df =4, χ² = 16.37). One way Analysis Of Variance (ANOVA) suggested the absence of any significant relationship between quality of life with marital status (f = 0.21; P = 0.92) and employment status (f = 0.26; P = 0.77). Also, Spearman test showed the absence of any significant relationship between quality of life with age (P = 0.60), and the elapsed duration from diagnosis (P = 0.68), however Spearman test showed significant relationship between quality of life and education status (P = 0.002, r = -0.84).

Conclusion:

With regard to results of this study, there was a direct correlation between the number of chemotherapy sessions and patients quality of life. The attitude of the population toward chemotherapy is usually inhibiting and negative, so patients, students and nurses should be trained about chemotherapy efficacy to improve their attitude about chemotherapy, which in turn would lead to improvement of the patients’ quality of life.

Environmental extremes versus ecological extremes: impact of a massive iceberg on the population dynamics of a high-level Antarctic marine predator

Extreme events have been suggested to play a disproportionate role in shaping ecological processes, but our understanding of the types of environmental conditions that elicit extreme consequences in natural ecosystems is limited. Here, we investigated the impact of a massive iceberg on the dynamics of a population of Weddell seals. Reproductive rates of females were reduced, but survival appeared unaffected. We also found suggestive evidence for a prolonged shift towards higher variability in reproductive rates. The annual number of females attending colonies showed unusual swings during the iceberg period, a pattern that was apparently the consequence of changes in sea-ice conditions. In contrast to the dramatic effects that were recorded in nearby populations of emperor penguins, our results suggest that this unusual environmental event did not have an extreme impact on the population of seals in the short-term, as they managed to avoid survival costs and were able to rapidly re-achieve high levels of reproduction by the end of the perturbation. Nevertheless, population projections suggest that even this modest impact on reproductive rates could negatively affect the population in the long run if such events were to occur more frequently, as is predicted by models of climate change.

Extended household transitions, race/ethnicity, and early childhood cognitive outcomes

Beyond mothers' union status transitions, other adults' transitions into and out of the household contribute to family instability, particularly in early childhood. Using the Early Childhood Longitudinal Study-Birth Cohort (N≅8550), this study examines associations between extended household transitions and age 2 cognitive development. A substantial minority of toddlers experiences these transitions, and their consequences vary by household member type, entry versus exit, and race/ethnicity. Extended household transitions predict lower cognitive scores for white children, but the selection of low-socioeconomic status families into extended households explains these disparities. Grandparent transitions predict significantly higher cognitive scores for African American and Latino children than whites, and some "other adult" transitions predict higher scores for Latinos than African Americans and whites. Extended household transitions' consequences are independent of co-occurring residential moves and partner transitions. Findings suggest that studying extended household transitions is useful for understanding children's early development, and their consequences vary by race/ethnicity.

REGULATION OF GEOGRAPHIC VARIABILITY IN HAPLOID:DIPLOD RATIOS OF BIPHASIC SEAWEED LIFE CYCLES(1)

The relative abundance of haploid and diploid individuals (H:D) in isomorphic marine algal biphasic cycles varies spatially, but only if vital rates of haploid and diploid phases vary differently with environmental conditions (i.e. conditional differentiation between phases). Vital rates of isomorphic phases in particular environments may be determined by subtle morphological or physiological differences. Herein, we test numerically how geographic variability in H:D is regulated by conditional differentiation between isomorphic life phases and the type of life strategy of populations (i.e. life cycles dominated by reproduction, survival or growth). Simulation conditions were selected using available data on H:D spatial variability in seaweeds. Conditional differentiation between ploidy phases had a small effect on the H:D variability for species with life strategies that invest either in fertility or in growth. Conversely, species with life strategies that invest mainly in survival, exhibited high variability in H:D through a conditional differentiation in stasis (the probability of staying in the same size class), breakage (the probability of changing to a smaller size class) or growth (the probability of changing to a bigger size class). These results were consistent with observed geographic variability in H:D of natural marine algae populations.

Sexual touching and difficulties with sexual arousal and orgasm among U.S. older adults

Little is known about the non-genitally-focused sexual behavior of those experiencing sexual difficulties. The objective of this study was to review the theory supporting a link between sexual touching and difficulties with sexual arousal and orgasm, and to examine associations between these constructs among older adults in the United States. The data were from the 2005-2006 National Social Life Health and Aging Project, which surveyed 3,005 community-dwelling men and women ages 57-85 years. The 1,352 participants who had had sex in the past year reported on their frequency of sexual touching and whether there had been a period of several months or more in the past year when they were unable to climax, had trouble getting or maintaining an erection (men) or had trouble lubricating (women). Women also reported how often they felt sexually aroused during partner sex in the last 12 months. The odds of being unable to climax were greater by 2.4 times (95% CI 1.2-4.8) among men and 2.8 times (95% CI 1.4-5.5) among women who sometimes, rarely or never engaged in sexual touching, compared to those who always engaged in sexual touching, controlling for demographic factors and physical health. These results were attenuated but persisted after controlling for emotional relationship satisfaction and psychological factors. Similar results were obtained for erectile difficulties among men and subjective arousal difficulties among women, but not lubrication difficulties among women. Infrequent sexual touching is associated with arousal and orgasm difficulties among older adults in the United States.

Evolutionary demography of iteroparous plants: incorporating non-lethal costs of reproduction into integral projection models

Understanding the selective forces that shape reproductive strategies is a central goal of evolutionary ecology. Selection on the timing of reproduction is well studied in semelparous organisms because the cost of reproduction (death) can be easily incorporated into demographic models. Iteroparous organisms also exhibit delayed reproduction and experience reproductive costs, although these are not necessarily lethal. How non-lethal costs shape iteroparous life histories remains unresolved. We analysed long-term demographic data for the iteroparous orchid Orchis purpurea from two habitat types (light and shade). In both the habitats, flowering plants had lower growth rates and this cost was greater for smaller plants. We detected an additional growth cost of fruit production in the light habitat. We incorporated these non-lethal costs into integral projection models to identify the flowering size that maximizes fitness. In both habitats, observed flowering sizes were well predicted by the models. We also estimated optimal parameters for size-dependent flowering effort, but found a strong mismatch with the observed flower production. Our study highlights the role of context-dependent non-lethal reproductive costs as selective forces in the evolution of iteroparous life histories, and provides a novel and broadly applicable approach to studying the evolutionary demography of iteroparous organisms.

Assessing the accuracy and power of population genetic inference from low-pass next-generation sequencing data

Next-generation sequencing (NGS) technologies have made it possible to address population genetic questions in almost any system, but high error rates associated with such data can introduce significant biases into downstream analyses, necessitating careful experimental design and interpretation in studies based on short-read sequencing. Exploration of population genetic analyses based on NGS has revealed some of the potential biases, but previous work has emphasized parameters relevant to human population genetics and further examination of parameters relevant to other systems is necessary, including situations where sample sizes are small and genetic variation is high. To assess experimental power to address several principal objectives of population genetic studies under these conditions, we simulated population samples under selective sweep, population growth, and population subdivision models and tested the power to accurately infer population genetic parameters from sequence polymorphism data obtained through simulated 4×, 8×, and 15× read depth sequence data. We found that estimates of population genetic differentiation and population growth parameters were systematically biased when inference was based on 4× sequencing, but biases were markedly reduced at even 8× read depth. We also found that the power to identify footprints of positive selection depends on an interaction between read depth and the strength of selection, with strong selection being recovered consistently at all read depths, but weak selection requiring deeper read depths for reliable detection. Although we have explored only a small subset of the many possible experimental designs and population genetic models, using only one SNP-calling approach, our results reveal some general patterns and provide some assessment of what biases could be expected under similar experimental structures.

Neutral theory for life histories and individual variability in fitness components

Individuals within populations can differ substantially in their life span and their lifetime reproductive success but such realized individual variation in fitness components need not reflect underlying heritable fitness differences visible to natural selection. Even so, biologists commonly argue that large differences in fitness components are likely adaptive, resulting from and driving evolution by natural selection. To examine this argument we use unique formulas to compute exactly the variance in life span and in lifetime reproductive success among individuals with identical (genotypic) vital rates (assuming a common genotype for all individuals). Such individuals have identical fitness but vary substantially in their realized individual fitness components. We show by example that our computed variances and corresponding simulated distribution of fitness components match those observed in real populations. Of course, (genotypic) vital rates in real populations are expected to differ by small but evolutionarily important amounts among genotypes, but we show that such differences only modestly increase variances in fitness components. We conclude that observed differences in fitness components may likely be evolutionarily neutral, at least to the extent that they are indistinguishable from distributions generated by neutral processes. Important consequences of large neutral variation are the following: Heritabilities for fitness components are likely to be small (which is in fact the case), small selective differences in life histories will be hard to measure, and the effects of random drift will be amplified in natural populations by the large variances among individuals.

Predictions of cancer incidence in Wielkopolska in 2018

Aim of the study

The cancer incidence in Wielkopolska in 2008 was one of the highest in the country and was higher than in Poland by 21% in men and by 14% in women. We can quantify the future burden of cancer from two different perspectives: the number of new cancer cases due to population change and new cases due to risk change. Making predictions of number of new cancer cases in Wielkopolska in 2018.

Material and methods

These projections of number of cancer cases, age specific rates and age-standardized rates for 2018 (all cancers and the most frequent cancers for men and women) has been based on the historical trends of cancer incidence in Wielkopolska in 1999-2008 and demographical prognosis of Central Statistical Office using the method of Hakulinen and Dyba.

Results

There will be over 8000 new cancer cases in men in Wielkopolska in 2018 and over 7000 in women. Compare to the period 2004-2008 the number of cancer cases will increase by 45% for men and by nearly 30% for women. About 2/3 of the increase in Wielkopolska is predicted to be connected with demography change, 1/3 with risk change.

Conclusions

The predicted increase of number of cancer cases in Wielkopolska in 2018 will be the result of: changes in the population (bigger impact of the older age groups), an influence of the risk factors (mainly smoking) and a participation in the screening programs.

The relative importance of reproductive assurance and automatic selection as hypotheses for the evolution of self-fertilization

BACKGROUND

The field of plant mating-system evolution has long been interested in understanding why selfing evolves from outcrossing. Many possible mechanisms drive this evolutionary trend, but most research has focused upon the transmission advantage of selfing and its ability to provide reproductive assurance when cross-pollination is uncertain. We discuss the shared conceptual framework of these ideas and their empirical support that is emerging from tests of their predictions over the last 25 years.

SCOPE

These two hypotheses are derived from the same strategic framework. The transmission advantage hypothesis involves purely gene-level selection, with reproductive assurance involving an added component of individual-level selection. Support for both of these ideas has been garnered from population-genetic tests of their predictions. Studies in natural populations often show that selfing increases seed production, but it is not clear if this benefit is sufficient to favour the evolution of selfing, and the ecological agents limiting outcross pollen are often not identified. Pollen discounting appears to be highly variable and important in systems where selfing involves multiple floral adaptations, yet seed discounting has rarely been investigated. Although reproductive assurance appears likely as a leading factor facilitating the evolution of selfing, studies must account for both seed and pollen discounting to adequately test this hypothesis.

CONCLUSIONS

The transmission advantage and reproductive assurance ideas describe components of gene transmission that favour selfing. Future work should move beyond their dichotomous presentation and focus upon understanding whether selection through pollen, seed or both explains the spread of selfing-rate modifiers in plant populations.

Variation in the Relationship Between Education and Marriage: Marriage Market Mismatch?

Educational expansion has led to greater diversity in the social backgrounds of college students. We ask how schooling interacts with this diversity to influence marriage formation among men and women. Relying on data from the 1979 National Longitudinal Survey of Youth (N = 3208), we use a propensity score approach to group men and women into social strata and multilevel event history models to test differences in the effects of college attendance across strata. We find a statistically significant, positive trend in the effects of college attendance across strata, with the largest effects of college on first marriage among the more advantaged and the smallest-indeed, negative-effects among the least advantaged men and women. These findings appear consistent with a mismatch in the marriage market between individuals' education and their social backgrounds.

Mate Availability and Women's Sexual Experiences in China

Data from the 1999-2000 Chinese Health and Family Life Survey were merged with community-level data from the 1982, 1990, and 2000 Chinese censuses to examine the relationship between the local sex ratio (number of men per 100 women) and sexual outcomes among women (N = 1,369). Consistent with hypotheses derived from demographic-opportunity theory, multilevel logistic regression analyses showed that women are more likely to be sexually active, to have had premarital sexual intercourse, to have been forced to have sex, and to test positive for a sexually transmitted infection when there is a relative abundance of age-matched men in their local community. Education, birth cohort, and geographic location also emerged as significant predictors of women's sexual experiences.

The 1918 influenza pandemic hastened the decline of tuberculosis in the United States: an age, period, cohort analysis

The effect of the 1918 influenza pandemic on other diseases is a neglected topic in historical epidemiology. This paper takes up the hypothesis that the influenza pandemic affected the long-term decline of tuberculosis through selective mortality, such that many people with tuberculosis were killed in 1918, depressing subsequent tuberculosis mortality and transmission. Regularly collected vital statistics data on mortality of influenza and tuberculosis in the US are presented and analyzed demographically. The available population-level data fail to contradict the selection hypothesis. More work is needed to understand fully the role of multiple morbidities in the 1918 influenza pandemic.

Reconstructing the dynamics of ancient human populations from radiocarbon dates: 10 000 years of population growth in Australia

Measuring trends in the size of prehistoric populations is fundamental to our understanding of the demography of ancient people and their responses to environmental change. Archaeologists commonly use the temporal distribution of radiocarbon dates to reconstruct population trends, but this can give a false picture of population growth because of the loss of evidence from older sites. We demonstrate a method for quantifying this bias, and we use it to test for population growth through the Holocene of Australia. We used model simulations to show how turnover of site occupation across an archaeological landscape, interacting with erasure of evidence at abandoned sites, can create an increase in apparent site occupation towards the present when occupation density is actually constant. By estimating the probabilities of abandonment and erasure from archaeological data, we then used the model to show that this effect does not account for the observed increase in occupation through the Holocene in Australia. This is best explained by population growth, which was low for the first part of the Holocene but accelerated about 5000 years ago. Our results provide new evidence for the dynamism of non-agricultural populations through the Holocene.

On detecting selective sweeps using single genomes

Identifying the genetic basis of human adaptation has remained a central focal point of modern population genetics. One major area of interest has been the use of polymorphism data to detect so-called “footprints” of selective sweeps – patterns produced as a beneficial mutation arises and rapidly fixes in the population. Based on numerous simulation studies and power analyses, the necessary sample size for achieving appreciable power has been shown to vary from a few individuals to a few dozen, depending on the test statistic. And yet, the sequencing of multiple copies of a single region, or of multiple genomes as is now often the case, incurs considerable cost. Enard et al. (2010) have recently proposed a method to identify patterns of selective sweeps using a single genome – and apply this approach to human and non-human primates (chimpanzee, orangutan, and macaque). They employ essentially a modification of the Hudson, Kreitman, and Aguade test – using heterozygous single nucleotide polymorphisms from single individuals, and divergence data from two closely related species (human–chimpanzee, human–orangutan, and human–macaque). Given the potential importance of this finding, we here investigate the properties of this statistic. We demonstrate through simulation that this approach is neither robust to demography nor background selection; nor is it robust to variable recombination rates.

Study methods, recruitment, sociodemographic findings, and demographic representativeness in the OPPERA study

This paper describes methods used in the project "Orofacial Pain Prospective Evaluation and Risk Assessment" (OPPERA) and evaluates sociodemographic characteristics associated with temporomandibular disorders (TMD) in the OPPERA case-control study. Representativeness was investigated by comparing sociodemographic profiles of OPPERA participants with population census profiles of counties near study sites and by comparing age and gender associations with TMD in OPPERA and the 2007 to 2009 US National Health Interview Survey. Volunteers aged 18 to 44 years were recruited at 4 US study sites: 3,263 people without TMD were enrolled into the prospective cohort study; 1,633 of them were selected as controls for the baseline case-control study. Cases were 185 volunteers with examiner-classified TMD. Distributions of some demographic characteristics among OPPERA participants differed from census profiles, although there was less difference in socioeconomic profiles. Odds of TMD was associated with greater age in this 18 to 44 year range; females had 3 times the odds of TMD as males; and relative to non-Hispanic-Whites, other racial groups had one-fifth the odds of TMD. Age and gender associations with chronic TMD were strikingly similar to associations observed in the US population. Assessments of representativeness in this demographically diverse group of community volunteers suggest that OPPERA case-control findings have good internal validity.

PERSPECTIVE

Demographic associations with TMD were consistent with population benchmarks and with other studies, suggesting broad applicability of these OPPERA findings. Greater occurrence of TMD in non-Hispanic-Whites than in other racial/ethnic groups and the lack of a socioeconomic gradient contradicts the disparities seen in many other health conditions.

The effectiveness of interventions in workplace health promotion as to maintain the working capacity of health care personal

Background

The increasing proportion of elderly people with respective care requirements and within the total population stands against aging personnel and staff reduction in the field of health care where employees are exposed to high load factors. Health promotion interventions may be a possibility to improve work situations and behavior.

Methods

A systematic literature search is conducted in 32 databases limited to English and German publications since 1990. Moreover, internet-searches are performed and the reference lists of identified articles are scanned. The selection of literature was done by two reviewers independently according to inclusion and exclusion criteria. Data extraction and tables of evidence are verified by a second expert just like the assessment of risk of bias by means of the Cochrane Collaboration’s tool.

Results

We identified eleven intervention studies and two systematic reviews. There were three randomized controlled trials (RCT) and one controlled trial without randomization (CCT) on the improvement of physical health, four RCT and two CCT on the improvement of psychological health and one RCT on both. Study duration ranged from four weeks to two years and the number of participants included from 20 to 345, with a median of 56. Interventions and populations were predominantly heterogeneous. In three studies intervention for the improvement of physical health resulted in less complaints and increased strength and flexibility with statistically significant differences between groups. Regarding psychological health interventions lead to significantly decreased intake of analgesics, better stress management, coping with workload, communication skills and advanced training.

Discussion

Taking into consideration the small to very small sample sizes, other methodological flaws like a high potential of bias and poor quality of reporting the validity of the results has to be considered as limited. Due to the heterogeneity of health interventions, study populations with differing job specializations and different lengths of study durations and follow-up periods, the comparison of results would not make sense.

Conclusions

Further research is necessary with larger sample sizes, with a sufficient study duration and follow-up, with a lower risk of bias, by considering of relevant quality criteria and with better reporting in publications.

Demographic Imperatives and Religious Markets: Considering the Individual and Interactive Roles of Fertility and Switching in Group Growth

Two models seeking to explain the growth and decline of religious groups are prevalent in the literature. The religious market approach emphasizes the role of intergroup competition and in doing so focuses on religious switching. Another perspective emphasizes demographic mechanisms, particularly fertility. Research to date has not considered how switching and fertility interact as mechanisms of growth. Switching and fertility share a significant role in the growth trajectory of a religious group. Early success in gaining members through switching has an important long-term impact which fertility alone cannot produce. The age of those switching into a group can also have significant consequences for the effects of fertility.

Social exposure to an antiretroviral treatment programme in rural KwaZulu-Natal

OBJECTIVE

To investigate the prevalence of social exposure to a large, government-run ART programme in rural South Africa.

METHOD

Clinical data on 6681 patients were matched with demographic data on a nearly complete cohort of 102,359 people residing in the programme catchment area. We calculated the proportion of residents in the demographic surveillance area that were members of a household, or resided in a compound where someone had initiated ART or received pre-ART care.

RESULTS

By January 2010, 3% of the population had initiated ART. However, 25% of the population shared household membership or resided in a compound with someone who had initiated ART; 40% shared household or living arrangements with people who had either initiated ART or were enrolled in pre-ART care.

CONCLUSION

Such high rates of social exposure suggest that ART programmes in HIV endemic areas are likely to have significant population-level effects on social norms and economic welfare. These results also point to the opportunity to reach large numbers of people with health and social services through existing ART programmes.

Frozen Film and FOSDIC Forms: Restoring the 1960 U.S. Census of Population and Housing

In this article, the authors describe a collaboration of the Minnesota Population Center (MPC), the U.S. Census Bureau, and the National Archives and Records Administration to restore the lost data from the 1960 Census. The data survived on refrigerated microfilm in a cave in Lenexa, Kansas. The MPC is now converting the data to usable form. Once the restored data are processed, the authors intend to develop three new data sources based on the 1960 census. These data will replace the most inadequate sample in the series of public-use census microdata spanning the years from 1850 to 2000, extend the chronological scope of the public census summary files, and provide a powerful new resource for the Census Bureau and its Research Data Centers.

A Half Century of Health Data for the U.S. Population: The Integrated Health Interview Series

The U.S. National Health Interview Survey (NHIS) is the world's longest survey time series of health data and a rich source of information on health conditions, behaviors, and care from the 1960s to the present. NHIS public-use files are difficult to use for long-term analysis, due to complex file structure, changes in questionnaire content, and evolving variable names and coding schemes. Researchers at the Minnesota Population Center have created the Integrated Health Interview Series (IHIS) to overcome these problems. IHIS provides access to thousands of consistently coded and well-documented NHIS variables on the Internet and makes it easy to analyze health trends and differentials. IHIS multiplies the value of NHIS data by allowing researchers to make consistent comparisons over half a century and thus to study U.S. health status as a dynamic process. This article describes the main features of IHIS and suggests fruitful avenues for historical research using these invaluable health data.

Genetic evidence for patrilocal mating behavior among Neandertal groups

The remains of 12 Neandertal individuals have been found at the El Sidrón site (Asturias, Spain), consisting of six adults, three adolescents, two juveniles, and one infant. Archaeological, paleontological, and geological evidence indicates that these individuals represent all or part of a contemporaneous social group of Neandertals, who died at around the same time and later were buried together as a result of a collapse of an underground karst. We sequenced phylogenetically informative positions of mtDNA hypervariable regions 1 and 2 from each of the remains. Our results show that the 12 individuals stem from three different maternal lineages, accounting for seven, four, and one individual(s), respectively. Using a Y-chromosome assay to confirm the morphological determination of sex for each individual, we found that, although the three adult males carried the same mtDNA lineage, each of the three adult females carried different mtDNA lineages. These findings provide evidence to indicate that Neandertal groups not only were small and characterized by low genetic diversity but also were likely to have practiced patrilocal mating behavior.

Why HIV/AIDS should be treated as exceptional: arguments from sub-Saharan Africa and Eastern Europe

The idea that HIV and AIDS gets too much attention and funding emerged in 2008 with a call to end 'AIDS exceptionalism.' This article outlines a short history of AIDS exceptionalism - the idea that HIV and AIDS require a response above and beyond 'normal' health interventions and is privileged in terms of attention and resources when compared with other diseases - and the reasons for the backlash to this idea. We argue that in some settings HIV and AIDS must be treated as exceptional. These are the hyperendemic countries of southern Africa, where HIV epidemics have shown substantial and lasting demographic and social impact, and parts of Eastern Europe where the epidemic is augmenting troubling demographic changes, such as declines in fertility rates and population growth, and impacting society in nuanced ways. Also included are resource-poor settings, mostly in Africa, where the combination of the high number of HIV infections and the cost of treatment have created issues concerning donor dependency and sustainable responses. An HIV epidemic must be seen as a long-wave event, with complex challenges to both HIV prevention and treatment responses. The article reviews the available data and literature to provide evidence for our arguments. We conclude that the perception that AIDS exceptionalism is outdated ignores the complexity of different HIV epidemics and obfuscates the challenges to effective responses.

The North Atlantic Population Project: Progress and Prospects

The North Atlantic Population Project (NAPP) is a massive database of historical census microdata from European and North American countries. The backbone of the project is the unique collection of completely digitized censuses providing information on the entire enumerated populations of each country. In addition, for some countries, the NAPP includes sample data from surrounding census years. In this article, the authors provide a brief history of the project, describe their progress to data and plans for the future, and discuss some potential implications of this unique data resource for social and economic research.

Evaluating regional differences in breast-feeding in French maternity units: a multi-level approach

OBJECTIVES

To study how individual and regional characteristics might explain regional variations in breast-feeding rates in maternity units and to identify outlier regions with very low or high breast-feeding rates.

DESIGN

Individual characteristics (mother and infant) were collected during hospital stay. All newborns fed entirely or partly on breast milk were considered breast-fed. Regional characteristics were extracted from census data. Statistical analysis included multi-level models and estimation of empirical Bayes residuals to identify outlier regions.

SETTING

All births in all administrative regions in France in 2003.

SUBJECTS

A national representative sample of 13 186 live births.

RESULTS

Breast-feeding rates in maternity units varied from 43 % to 80 % across regions. Differences in the distribution of individual characteristics accounted for 55 % of these variations. We identified two groups of regions with the lowest and highest breast-feeding rates, after adjusting for individual-level characteristics. In addition to maternal occupation and nationality, the social characteristics of regions, particularly the population's educational level and the percentage of non-French residents, were significantly associated with breast-feeding rates.

CONCLUSIONS

Social characteristics at both the individual and regional levels influence breast-feeding rates in maternity units. Promotion policies should be directed at specific regions, groups within the community and categories of mothers to reduce the gaps and increase the overall breast-feeding rate.

Fertility control in historical China revisited: New Methods for an Old Debate

We revisit the debate over deliberate control of reproduction in historical China through a reanalysis of data from the Qing (1644-911) Imperial Lineage that accounts for physiological or other differences between couples that affected their chances of having children. Even though studies of contemporary and historical European fertility suggest that failing to control for such differences may obscure evidence of parity-specific control, previous studies of historical Chinese fertility have not accounted for them. We show that in the Lineage, failure to account for such differences leads the association between number of children already born and the chances of having another birth to appear to be positive, but that once they are accounted for properly, the relationship is inverted. Based on this, we conclude that lineage members adjusted their reproductive behavior based on the number of children. We also show that the sex composition and survival of previous births affected reproductive behavior. We conclude by suggesting that one way forward in the ongoing debate over fertility control in historical China is through application of such methods to other datasets and comparison of results. We also suggest that progress in the debate over fertility in historical China has been impeded by confusion over the definition of fertility control, so that some behaviors are recognized as fertility control by some parties in the debate but not others.

The effects of phenological mismatches on demography

Climate change is altering the phenology of species across the world, but what are the consequences of these phenological changes for the demography and population dynamics of species? Time-sensitive relationships, such as migration, breeding and predation, may be disrupted or altered, which may in turn alter the rates of reproduction and survival, leading some populations to decline and others to increase in abundance. However, finding evidence for disrupted relationships, or lack thereof, and their demographic effects, is difficult because the necessary detailed observational data are rare. Moreover, we do not know how sensitive species will generally be to phenological mismatches when they occur. Existing long-term studies provide preliminary data for analysing the phenology and demography of species in several locations. In many instances, though, observational protocols may need to be optimized to characterize timing-based multi-trophic interactions. As a basis for future research, we outline some of the key questions and approaches to improving our understanding of the relationships among phenology, demography and climate in a multi-trophic context. There are many challenges associated with this line of research, not the least of which is the need for detailed, long-term data on many organisms in a single system. However, we identify key questions that can be addressed with data that already exist and propose approaches that could guide future research.

Building the bridge between animal movement and population dynamics

While the mechanistic links between animal movement and population dynamics are ecologically obvious, it is much less clear when knowledge of animal movement is a prerequisite for understanding and predicting population dynamics. GPS and other technologies enable detailed tracking of animal location concurrently with acquisition of landscape data and information on individual physiology. These tools can be used to refine our understanding of the mechanistic links between behaviour and individual condition through 'spatially informed' movement models where time allocation to different behaviours affects individual survival and reproduction. For some species, socially informed models that address the movements and average fitness of differently sized groups and how they are affected by fission-fusion processes at relevant temporal scales are required. Furthermore, as most animals revisit some places and avoid others based on their previous experiences, we foresee the incorporation of long-term memory and intention in movement models. The way animals move has important consequences for the degree of mixing that we expect to find both within a population and between individuals of different species. The mixing rate dictates the level of detail required by models to capture the influence of heterogeneity and the dynamics of intra- and interspecific interaction.

Decennial Life Tables for the White Population of the United States, 1790-1900

This article constructs new life tables for the white population of the United States in each decade between 1790 and 1900. Drawing from several recent studies, it suggests best estimates of life expectancy at age 20 for each decade. These estimates are fitted to new standards derived from the 1900-02 rural and 1900-02 overall DRA life tables using a two-parameter logit model with fixed slope. The resulting decennial life tables more accurately represent sex-and age-specific mortality rates while capturing known mortality trends.

Dietary supplement use by South Korean adults: Data from the national complementary and alternative medicine use survey (NCAMUS) in 2006

There has been little data on the prevalence of supplement use and the characteristics of the dietary supplement users in the Republic of Korea. This study presents the prevalence and the details of any dietary supplement use and the characteristics of the adults who use dietary supplements in the Republic of Korea. Between May 18 and June 16, 2006, nationwide and population-weighted personal interviews with 6,201 adult aged from 30 to 69 years were conducted and the final sample consisted of 3,000 people with a 49.8% response rate. We examined the prevalence and details of the use of dietary supplements and the characteristics of those who use the dietary supplement among adults. About sixty two percent of adults had taken any dietary supplement during the previous 12-month period in 2006. The most commonly reported dietary supplement was ginseng, followed by multivitamins, glucosamine, probiotics, and vitamin C. Female (versus male), an older age group, a higher family income, those living in metropolitan cities, those with marital experience, those with a higher level of education, and those having medical problems had a greater likelihood of reporting the use of any dietary supplements. The particular relationships differed depending on the type of supplement. The most Korean adults took one more dietary supplement and the dietary supplement users had different demographic and health characteristics compared to those of the nonusers. Research on diet supplements by the medical community is needed in the future.

The biology and some population parameters of the grasshopper, Ronderosia bergi, under laboratory conditions

Some biological and population parameters of Ronderosia bergi (Stål) (Orthoptera: Acrididae: Melanoplinae) were estimated by monitoring five cohorts of the first generation (F1) of individuals born in captivity from grasshoppers collected in the South of Misiones province, northeastern Argentina, and held under controlled conditions (30 degrees C, 14:10 L:D, 40% RH). The mean embryonic development time was 40.6 +/- 1.7 days. Five nymphal instars were recorded. Total duration of nymphal development was 30.8 +/- 0.54 days. The mean lifespan of cohorts was 22.6 +/- 0.7 weeks. The number of egg-pods per female was 7.6 +/- 1.44, and the amount of eggs per egg-pod was 16.45 +/- 0.85. Mean fecundity was 125 +/- 5.83 eggs per female with an oviposition rate of 1.55 +/- 0.57 eggs/female/day. Survivorship curves showed that mortality was concentrated in the final weeks of adulthood, and the life expectancy curve decreased accordingly. The population parameters estimated gave the following values: the net rate of reproduction (R(0)) was 46.75 +/- 11.2, generation time (T) was 18.87 +/- 1.67 weeks, duplication time (D) was 3.31 +/- 0.34, the intrinsic rate of population growth (r(m)) was 0.21 +/- 0.021 and the finite rate of population increase (lambda) was 1.24 +/- 0.026. The reproductive values (V(x)) indicated that the largest contribution of females to the subsequent generation was between weeks 15 and 25.

Using administrative data to estimate population displacement and resettlement following a catastrophic U.S. disaster

After a large scale evacuation, authorities need to know the new and frequently changing population distributions in order to meet needs for housing, schools, health care, and other services. This paper reviews literature from the fields of demography and other disciplines to identify available administrative data sets that can form the basis of sound, relevant, and timely county-level population estimates following a catastrophic U.S. event. The most appropriate data to estimate population in damaged counties will be disaster-specific data such as housing damage estimates and FEMA applicant counts initially, and later electric accounts and USPS active residences. In heavily damaged counties, data on electric accounts and USPS active residences may not be consistently collected for many months, during which time sample surveys may be needed. For counties that receive an influx of population, school enrollment data provide the most appropriate basis for population estimates. Population estimates for large, heavily damaged counties are highly uncertain. Sensitivity analysis when using estimates for planning in these areas is recommended. The Census Bureau can build on this research by codifying recommendations to local authorities for developing frequent post-disaster population estimates.