The relationship between the effective number of breeders (Nb) and the generational effective size (Ne) has rarely been examined empirically in species with overlapping generations and iteroparity. Based on a suite of 11 microsatellite markers, we examine the relationship between Nb, Ne and census population size (Nc) in 14 brook trout (Salvelinus fontinalis) populations inhabiting 12 small streams in Nova Scotia and sampled at least twice between 2009 and 2015. Unbiased estimates of Nb obtained with individuals of a single cohort, adjusted on the basis of age at first maturation (α) and adult lifespan (AL), were from 1.66 to 0.24 times the average estimates of Ne obtained with random samples of individuals of mixed ages (i.e. [Formula: see text]). In turn, these differences led to adjusted Ne estimates that were from nearly five to 0.7 times the estimates derived from mixed-aged individuals. These differences translate into the same range of variation in the ratio of effective to census population size [Formula: see text] within populations. Adopting [Formula: see text] as the more precise and unbiased estimates, we found that these brook trout populations differ markedly in their effective to census population sizes (range approx. 0.3 to approx. 0.01). Using AgeNe, we then showed that the variance in reproductive success or reproductive skew varied among populations by a factor of 40, from Vk/k ≈ 5 to 200. These results suggest wide differences in population dynamics, probably resulting from differences in productivity affecting the intensity of competition for access to mates or redds, and thus reproductive skew. Understanding the relationship between Ne, Nb and Nc, and how these relate to population dynamics and fluctuations in population size, are important for the design of robust conservation strategies in small populations with overlapping generations and iteroparity.
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http://dx.doi.org/10.1098/rspb.2015.2601 | DOI Listing |
Sci Rep
January 2025
Emergency Department, The State Key Laboratory for Complex, Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China.
Variation in the incidence, survival rate and factors associated with survival after cardiac arrest in China is reported. Some studies have tried to fill the knowledge gap regarding the epidemiology of cardiac arrest in China but were unable to identify reasons for the reported differences. Therefore, the purpose of this study was to describe Chinese management of cardiac arrest, particularly from the perspective of compression, ventilation, monitoring, treatment, and extracorporeal cardiopulmonary resuscitation.
View Article and Find Full Text PDFNat Commun
January 2025
Florida Museum of Natural History, Dickinson Hall, 1659 Museum Road, Gainesville, FL, 32611, USA.
The Thorny Skate (Amblyraja radiata) is a vulnerable species displaying a discrete size-polymorphism in the northwest Atlantic Ocean (NWA). We conducted whole genome sequencing of samples collected across its range. Genetic diversity was similar at all sampled sites, but we discovered a ~ 31 megabase bi-allelic supergene associated with the size polymorphism, with the larger size allele having introgressed in the last ~160,000 years B.
View Article and Find Full Text PDFAnn Fam Med
January 2025
Department of Family and Preventive Medicine, Emory University, Atlanta, Georgia.
Purpose: Family medicine research is essential to improving population health. It has the unique ability to answer questions about health care outcomes and use those insights to impact communities. Increasing research capacity continues to be a challenge; however, recent literature has touted the success of incentivization in several academic medicine specialties.
View Article and Find Full Text PDFBMJ Open
January 2025
Department of Community Medicine and Family Medicine, All India Institute of Medical Sciences, Bhubaneswar, Odisha, India.
Background: The avoidable causes of infant mortality should be identified, and interventions should be made to improve the infant mortality rate. The cause of infant deaths should be assessed in both medical and social contexts.
Objectives: We aimed to determine the medical causes of infant mortality by verbal autopsy and its determinants in two rural blocks of the Khordha district of Odisha and assess the pathway of care and delay in seeking care for the illness preceding infant death using the three-delay model.
Infect Dis Now
January 2025
Department of Global Health and Development, London School of Hygiene and Tropical Medicine, UK.
Antimicrobial resistance (AMR) poses a global health challenge, particularly in maritime environments where unique conditions foster its emergence and spread. Characterized by confined spaces, high population density, and extensive global mobility, ships create a setting ripe for the development and dissemination of resistant pathogens. This review aims to analyse the contributing factors, epidemiological challenges, mitigation strategies specific to AMR on ships and to propose future research directions, bridging a significant gap in the literature.
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