Effective population size is a fundamental parameter in population genetics, evolutionary biology, and conservation biology, yet its estimation can be fraught with difficulties. Several methods to ...estimate Ne from genetic data have been developed that take advantage of various approaches for inferring Ne. The ability of these methods to accurately estimate Ne, however, has not been comprehensively examined. In this study, we employ seven of the most cited methods for estimating Ne from genetic data (Colony2, CoNe, Estim, MLNe, ONeSAMP, TMVP, and NeEstimator including LDNe) across simulated datasets with populations experiencing migration or no migration. The simulated population demographies are an isolated population with no immigration, an island model metapopulation with a sink population receiving immigrants, and an isolation by distance stepping stone model of populations. We find considerable variance in performance of these methods, both within and across demographic scenarios, with some methods performing very poorly. The most accurate estimates of Ne can be obtained by using LDNe, MLNe, or TMVP; however each of these approaches is outperformed by another in differing demographic scenario. Knowledge of the approximate demography of population as well as the availability of temporal data largely improves Ne estimates.
Background: Emergency general surgery (EGS) conditions cause a disproportionately high degree of morbidity and mortality among surgical patients. The objective of our study was to generate estimates ...of the potential access to EGS care within various driving distances for Ontario residents in each geographic region. Methods: Institutional details were collected using a survey of all hospitals offering urgent and emergent general surgical care in Ontario (n = 114). The locations of these hospitals were mapped using geographic information systems (GIS), and land catchment areas were modelled for 30-, 45-, 60- and 90-minute travel times using the 2019 Ontario road network. Population data were reported on the basis of the 2016 census blocks, which are the smallest geographic units by which to report population. Travel distances were determined between the geographic centroid of the census block and the closest hospital. Results were stratified for certain characteristics offered by the institution, such as EGS care available (n = 114), dedicated EGS service model (n = 36), 24/7 emergency department (ED) (n = 97) and 24/7 operating room (OR) capabilities (n = 76). Results: Nearly all (96%, n = 12 933 892) of the Ontario population lives within 30 minutes' driving time to a hospital that provides care to EGS patients, and 93% (n = 12 471 908) can access a hospital with 24/7 OR capabilities in this same time frame. Around-the-clock ED availability within 30 minutes is potentially accessible for 93% (n = 12 471 908) of the population. However, only 76% (n = 10 220 018) live within 30 minutes of a facility with an EGS model of care. Substantial regional disparities are present and appear to particularly affect remote communities. Conclusion: Most Ontario residents live within a 30-minute driving distance of a hospital able to provide emergent or urgent general surgical care, with slightly fewer able to access 24/7 operative facilities. Despite this, striking differences persist in access for remote and rural areas of the province.
The household registration (hukou) system in China, classifying each person as a rural or an urban resident, is a major means of controlling populatin mobility and determining eligibility for ...state-provided services and welfare. Established in the late 1950s, it was initially used to bar rural-to-urban migration. After the late 1970s reforms, an inflow of rural migrant workers was allowed into the cities to meet labor demands in the burgeoning export industries and urban services without, however, changing the migrants' registered status, thus precluding their access to subsidized housing and other benefits available to those with urban registration. While there have been many calls for reforming this system, progress has been limited. Proposed reforms have attracted increasing academic and media attention.
How can we all work together to eliminate the avoidable injustices that plague our health care system and society?Health is determined by far more than a person's choices and behaviors. Social and ...political conditions, economic forces, physical environments, institutional policies, health care system features, social relationships, risk behaviors, and genetic predispositions all contribute to physical and mental well-being. In America and around the world, many of these factors are derived from a lingering history of unequal opportunities and unjust treatment for people of color and other vulnerable communities. But they aren't the only ones who suffer because of these disparities—everyone is impacted by the factors that degrade health for the least advantaged among us.In Why Are Health Disparities Everyone's Problem? Dr. Lisa Cooper shows how we can work together to eliminate the injustices that plague our health care system and society. The book follows Cooper's journey from her childhood in Liberia, West Africa, to her thirty-year career working first as a clinician and then as a health equity researcher at Johns Hopkins University. Drawing on her experiences, it explores how differences in communication and the quality of relationships affect health outcomes. Through her work as the founder and director of the Johns Hopkins Center for Health Equity, it details the actions and policies needed to reduce and eliminate the conditions that are harming us all. Cooper reveals with compelling detail how health disparities are crippling our health care system and society, driving up health care costs, leading to adverse health outcomes and ultimately an enormous burden of human suffering. Why Are Health Disparities Everyone's Problem? demonstrates the ways in which everyone's health is interconnected, both within communities and across the globe. Cooper calls for a new kind of herd immunity, when a sufficiently high proportion of people, across race and social class, become immune to harmful social conditions through "vaccination" with solidarity among groups and opportunities created by institutional and societal practices and policies. By acknowledging and acting upon that interconnectedness, she believes everyone can help to create a healthier world.Features• Raises readers' health care inequities literacy through an approachable narrative with specific examples• Introduces the concept of "herd immunity" as it applies to building communal awareness of systemic injustices• Features sections that underscore key takeaways• Includes contributions from the world's leading minds through their research findings and quotations• Guides readers on what can be done at an individual level as a patient, public health professional, and community member • Includes inspiring stories of effective health equity studies and practices around the world, from Ghana's ADHINCRA Project addressing hypertension control to Baltimore's BRIDGE Study for depression in African Americans and the Maryland and Pennsylvania–based RICH LIFE Project for hypertension, diabetes, and other medical conditionsJohns Hopkins WavelengthsIn classrooms, field stations, and laboratories in Baltimore and around the world, the Bloomberg Distinguished Professors of Johns Hopkins University are opening the boundaries of our understanding of many of the world's most complex challenges. The Johns Hopkins Wavelengths book series brings readers inside their stories, illustrating how their pioneering discoveries benefit people in their neighborhoods and across the globe in artificial intelligence, cancer research, food systems' environmental impacts, health equity, science diplomacy, and other critical arenas of study. Through these compelling narratives, their insights will spark conversations from dorm rooms to dining rooms to boardrooms.
Human land transformation is one of the leading causes of vertebrate population declines. These declines are thought to be partly due to decreased connectivity and habitat loss reducing animal ...population sizes in disturbed habitats. With time, this can lead to declines in effective population size and genetic diversity which restrict the ability of wildlife to efficiently cope with environmental change through genetic adaptation. However, it is not well understood whether these effects generally hold across taxa. We address this question by repurposing and synthesizing raw microsatellite data from online repositories for 19 amphibian species sampled at 554 georeferenced sites in North America. For each site, we estimated gene diversity, allelic richness, effective population size, and population differentiation. Using binary urban‐rural census designations, and continuous measures of human population density, the Human Footprint Index, and impervious surface cover, we tested for generalizable effects of human land use on amphibian genetic diversity. We found minimal evidence, either positive or negative, for relationships between genetic metrics and urbanization. Together with previous work on focal species that also found varying effects of urbanization on genetic composition, it seems likely that the consequences of urbanization are not easily generalizable within or across amphibian species. Questions about the genetic consequences of urbanization for amphibians should be addressed on a case‐by‐case basis. This contrasts with general negative effects of urbanization in mammals and consistent, but species‐specific, positive and negative effects in birds.
Just six decades ago, the world was experiencing remarkably high population growth rates, which led to the coining of the term ‘demographic bomb’ to describe concerns associated with population size. ...At the time, the global population was three billion. Since then, an extra billion people have been added every 12 years. However, the pre-eminent demographic challenge of the twenty-first century is population ageing, a global, irreversible and unprecedented trend. The number of people aged 65 and over has almost doubled since the turn of the century and currently accounts for 10% of the global population. An extra billion people are expected to age into the older category within the next 35 years. In Europe, half of the population is above 45 years of age, and the number of those above 65 years old is greater than the number of children under 15. Commonly referred to as the ‘silver tsunami’, it is feared that the increasing number of older people will have a destructive impact on economies and social systems. Never before have our lives been longer, our families smaller and our societies more multigenerational. The new reality of longevity requires a shift in how we approach ageing. This article explores ways to cope with the challenges of the silver era we are heading towards.
This book traces the history of population dynamics. It details the problems that scientists face when governments ask them for reliable predictions to help control epidemic, manage renewable ...resources, or anticipate demographic evolutions such as aging.
Pulsatilla patens s.s. is a one of the most endangered plant species in Europe. The present range of this species in Europe is highly fragmented and the size of the populations has been dramatically ...reduced in the past 50 years. The rapid disappearance of P. patens localities in Europe has prompted the European Commission to initiate active protection of this critically endangered species. The aim of this study was to estimate the degree and distribution of genetic diversity within European populations of this endangered species. We screened 29 populations of P. patens using a set of six microsatellite primers. The results of our study indicate that the analyzed populations are characterized by low levels of genetic diversity (Ho = 0.005) and very high levels of inbreeding (FIS = 0.90). These results suggest that genetic erosion could be partially responsible for the lower fitness in smaller populations of this species. Private allelic richness was very low, being as low as 0.00 for most populations. Average genetic diversity over loci and mean number of alleles in P. patens populations were significantly correlated with population size, suggesting severe genetic drift. The results of AMOVA point to higher levels of variation within populations than between populations.The results of Structure and PCoA analyses suggest that the genetic structure of the studied P. patens populations fall into three clusters corresponding to geographical regions. The most isolated populations (mostly from Romania) formed a separate group with a homogeneous gene pool located at the southern, steppic part of the distribution range. Baltic, mostly Polish, populations fall into two genetic groups which were not fully compatible with their geographic distribution.Our results indicate the serious genetic depauperation of P. patens in the western part of its range, even hinting at an ongoing extinction vortex. Therefore, special conservation attention is required to maintain the populations of this highly endangered species of European Community interest.
Concern about the size of the world's population did not begin with the "population bomb" in 1968. It arose in the aftermath of World War I and was understood as an issue with far-reaching ...ecological, agricultural, economic, and geopolitical consequences. The world population problem concerned the fertility of soil as much as the fertility of women, always involving both "earth" and "life."
Global Populationtraces the idea of a world population problem as it evolved from the 1920s through the 1960s. The growth and distribution of the human population over the planet's surface came deeply to shape the characterization of "civilizations" with different standards of living. It forged the very ideas of development, demographically defined three worlds, and, for some, an aspirational "one world."
Drawing on international conference transcripts and personal and organizational archives, this book reconstructs the twentieth-century population problem in terms of migration, colonial expansion, globalization, and world food plans. Population was a problem in which international relations and intimate relations were one. Global Population ultimately shows how a geopolitical problem about sovereignty over land morphed into a biopolitical solution, entailing sovereignty over one's person.
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