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Trends in Ecology & Evolution Oct 2023Our ability to assess the threat posed by the genetic load to small and declining populations has been greatly improved by advances in genome sequencing and... (Review)
Review
Our ability to assess the threat posed by the genetic load to small and declining populations has been greatly improved by advances in genome sequencing and computational approaches. Yet, considerable confusion remains around the definitions of the genetic load and its dynamics, and how they impact individual fitness and population viability. We illustrate how both selective purging and drift affect the distribution of deleterious mutations during population size decline and recovery. We show how this impacts the composition of the genetic load, and how this affects the extinction risk and recovery potential of populations. We propose a framework to examine load dynamics and advocate for the introduction of load estimates in the management of endangered populations.
Topics: Genetics, Population; Genetic Load; Population Density; Inbreeding; Genetic Variation
PubMed: 37344276
DOI: 10.1016/j.tree.2023.05.008 -
Ecology and Evolution May 2024Canid species are highly adaptable, including to urban and peri-urban areas, where they can come into close contact with people. Understanding the mechanisms of wild...
Canid species are highly adaptable, including to urban and peri-urban areas, where they can come into close contact with people. Understanding the mechanisms of wild canid population persistence in these areas is key to managing any negative impacts. The resource dispersion hypothesis predicts that animal density increases and home range size decreases as resource concentration increases, and may help to explain how canids are distributed in environments with an urban-natural gradient. In Australia, dingoes have adapted to human presence, sometimes living in close proximity to towns. Using a targeted camera trap survey and spatial capture-recapture models, we estimated spatial variation in the population density and detection rates of dingoes on Worimi Country in the Great Lakes region of the NSW coast. We tested whether dingo home range and population densities varied across a gradient of human population density, in a mixed-use landscape including, urban, peri-urban, and National Park environs. We found human population density to be a strong driver of dingo density (ranging from 0.025 to 0.433 dingoes/km across the natural-urban gradient), and to have a negative effect on dingo home range size. The spatial scale parameter changed depending on survey period, being smaller in the peak tourism period, when human population increases in the area, than in adjacent survey periods, potentially indicating reduced home range size when additional resources are available. Our study highlights the potential value of managing anthropogenic resource availability to manage carnivore densities and potential risk of human-carnivore interactions.
PubMed: 38779530
DOI: 10.1002/ece3.11404 -
Nature Sep 2023The wildland-urban interface (WUI) is where buildings and wildland vegetation meet or intermingle. It is where human-environmental conflicts and risks can be...
The wildland-urban interface (WUI) is where buildings and wildland vegetation meet or intermingle. It is where human-environmental conflicts and risks can be concentrated, including the loss of houses and lives to wildfire, habitat loss and fragmentation and the spread of zoonotic diseases. However, a global analysis of the WUI has been lacking. Here, we present a global map of the 2020 WUI at 10 m resolution using a globally consistent and validated approach based on remote sensing-derived datasets of building area and wildland vegetation. We show that the WUI is a global phenomenon, identify many previously undocumented WUI hotspots and highlight the wide range of population density, land cover types and biomass levels in different parts of the global WUI. The WUI covers only 4.7% of the land surface but is home to nearly half its population (3.5 billion). The WUI is especially widespread in Europe (15% of the land area) and the temperate broadleaf and mixed forests biome (18%). Of all people living near 2003-2020 wildfires (0.4 billion), two thirds have their home in the WUI, most of them in Africa (150 million). Given that wildfire activity is predicted to increase because of climate change in many regions, there is a need to understand housing growth and vegetation patterns as drivers of WUI change.
Topics: Humans; Forests; Wildfires; Wilderness; Urbanization; Geographic Mapping; Cities; Africa; Europe; Housing; Population Density; Biomass; Climate Change
PubMed: 37468636
DOI: 10.1038/s41586-023-06320-0 -
Microbiology (Reading, England) Sep 2023Quorum sensing is a term describing bacterial cell-to-cell communication systems for monitoring and responding to changes in population density. This primer serves as an...
Quorum sensing is a term describing bacterial cell-to-cell communication systems for monitoring and responding to changes in population density. This primer serves as an introduction to the canonical LuxR-LuxI-type quorum sensing circuits common to many species of Gram-negative bacteria. Quorum sensing can synchronize behaviours across a community. Different species employ quorum sensing strategies to control specific behaviours such as bioluminescence, virulence factor production, secondary metabolite production, and biofilm formation.
Topics: Quorum Sensing; Virulence Factors; Trans-Activators
PubMed: 37655474
DOI: 10.1099/mic.0.001343 -
Injury Prevention : Journal of the... Oct 2023To characterise risk factors for fatal drowning in California, USA to inform priorities for prevention, policy and research.
OBJECTIVE
To characterise risk factors for fatal drowning in California, USA to inform priorities for prevention, policy and research.
METHODS
This retrospective population-based epidemiological review of death certificate data evaluated fatal drowning events in California from 2005 to 2019. Unintentional, intentional, and undetermined drowning deaths and rates were described by person (age, sex, race) and context-based variables (region and body of water).
RESULTS
California's fatal drowning rate was 1.48 per 100 000 population (n=9237). Highest total fatal drowning rates occurred in the lower population density northern regions, among older adults (75-84 years: 2.54 per 100 000 population; 85+: 3.47 per 100 000 population) and non-Hispanic American Indian or Alaska Native persons (2.84 per 100 000 population). Male drowning deaths occurred at 2.7 times the rate of females; drowning deaths occurred mainly in swimming pools (27%), rivers/canals (22.4%) and coastal waters (20.2%). The intentional fatal drowning rate increased 89% during the study period.
CONCLUSIONS
California's overall fatal drowning rate was similar to the rest of the USA but differed among subpopulations. These divergences from national data, along with regional differences in drowning population and context-related characteristics, underscore the need for state and regional level analyses to inform drowning prevention policy, programmes and research.
Topics: Female; Humans; Male; Infant; Aged; Drowning; Retrospective Studies; Risk Factors; California; Rivers
PubMed: 37208006
DOI: 10.1136/ip-2023-044862 -
Communications Biology Sep 2023Our brains continuously acquire and store memories through synaptic plasticity. However, spontaneous synaptic changes can also occur and pose a challenge for maintaining...
Our brains continuously acquire and store memories through synaptic plasticity. However, spontaneous synaptic changes can also occur and pose a challenge for maintaining stable memories. Despite fluctuations in synapse size, recent studies have shown that key population-level synaptic properties remain stable over time. This raises the question of how local synaptic plasticity affects the global population-level synaptic size distribution and whether individual synapses undergoing plasticity escape the stable distribution to encode specific memories. To address this question, we (i) studied spontaneously evolving spines and (ii) induced synaptic potentiation at selected sites while observing the spine distribution pre- and post-stimulation. We designed a stochastic model to describe how the current size of a synapse affects its future size under baseline and stimulation conditions and how these local effects give rise to population-level synaptic shifts. Our study offers insights into how seemingly spontaneous synaptic fluctuations and local plasticity both contribute to population-level synaptic dynamics.
Topics: Brain; Neuronal Plasticity; Population Density; Population Dynamics
PubMed: 37696988
DOI: 10.1038/s42003-023-05303-1 -
Nature Jan 2024Multiple sclerosis (MS) is a neuro-inflammatory and neurodegenerative disease that is most prevalent in Northern Europe. Although it is known that inherited risk for MS...
Multiple sclerosis (MS) is a neuro-inflammatory and neurodegenerative disease that is most prevalent in Northern Europe. Although it is known that inherited risk for MS is located within or in close proximity to immune-related genes, it is unknown when, where and how this genetic risk originated. Here, by using a large ancient genome dataset from the Mesolithic period to the Bronze Age, along with new Medieval and post-Medieval genomes, we show that the genetic risk for MS rose among pastoralists from the Pontic steppe and was brought into Europe by the Yamnaya-related migration approximately 5,000 years ago. We further show that these MS-associated immunogenetic variants underwent positive selection both within the steppe population and later in Europe, probably driven by pathogenic challenges coinciding with changes in diet, lifestyle and population density. This study highlights the critical importance of the Neolithic period and Bronze Age as determinants of modern immune responses and their subsequent effect on the risk of developing MS in a changing environment.
Topics: Humans; Datasets as Topic; Diet; Europe; Genetic Predisposition to Disease; Genetics, Medical; Genome, Human; Grassland; History, 15th Century; History, Ancient; History, Medieval; Human Migration; Life Style; Multiple Sclerosis; Neurodegenerative Diseases; Population Density
PubMed: 38200296
DOI: 10.1038/s41586-023-06618-z -
Microbiology Spectrum Aug 2023The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was introduced in Algeria in March 2020. This...
The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was introduced in Algeria in March 2020. This study aimed to estimate the seroprevalence of SARS-CoV-2 infection in Oran, Algeria, and to identify factors associated with seropositivity. This was a cross-sectional seroprevalence study conducted between 7 and 20 January 2021 across all 26 municipalities in the province of Oran. The study employed a random cluster sampling technique stratified by age and sex to select participants from households, who were then administered a rapid serological test. The overall seroprevalence and specific seroprevalences by municipality were calculated, and the number of COVID-19 cases in Oran was estimated. The correlation between population density and seroprevalence was also examined. Among the participants, 422 (35.6%; 95% confidence interval [CI], 32.9 to 38.4) had a positive serological test for SARS-CoV-2, and eight municipalities had seroprevalence rates above 73%. We found a strong positive correlation between population density and seroprevalence ( = 0.795, < 0.001), indicating that areas with higher population density had higher numbers of positive COVID-19 cases. Our study provides evidence of a high seroprevalence of SARS-CoV-2 infection in Oran, Algeria. The estimated number of cases based on seroprevalence is much higher than the number of cases confirmed by PCR. Our findings suggest that a large proportion of the population has been infected with SARS-CoV-2, highlighting the need for continued surveillance and control measures to prevent further spread of the virus. This is the first and only seroprevalence study of COVID-19 conducted in the general population in Algeria prior to the national vaccination campaign against COVID-19. The significance of this study lies in its contribution to our understanding of the spread of the virus in the population before the implementation of the vaccination program.
Topics: Humans; COVID-19; SARS-CoV-2; Cross-Sectional Studies; Seroepidemiologic Studies; Pandemics; Antibodies, Viral
PubMed: 37284756
DOI: 10.1128/spectrum.00876-23 -
Cancer Aug 2023Breast cancer survivors are at a higher risk of cardiovascular disease (CVD) morbidity and mortality compared with the general population. The impact of objective social...
BACKGROUND
Breast cancer survivors are at a higher risk of cardiovascular disease (CVD) morbidity and mortality compared with the general population. The impact of objective social and built neighborhood attributes on CVD risk in a cohort of female breast cancer survivors was examined.
METHODS
The 3975 participants came from the Pathways Study, a prospective cohort of women with invasive breast cancer from an integrated health care system in northern California. Women diagnosed with breast cancer from 2006 through 2013 were enrolled on average approximately 2 months after diagnosis. Their baseline addresses were geocoded and appended to neighborhood attributes for racial/ethnic composition, socioeconomic status (SES), population density, urbanization, crime, traffic density, street connectivity, parks, recreational facilities, and retail food environment. Incident CVD events included ischemic heart disease, heart failure, cardiomyopathy, or stroke. Cox proportional hazards models estimated associations of neighborhood attributes with CVD risk, which accounted for clustering by block groups. Fully adjusted models included sociodemographic, clinical, and behavioral factors.
RESULTS
During follow-up through December 31, 2018, 340 participants (8.6%) had CVD events. A neighborhood racial/ethnic composition measure, percent of Asian American/Pacific Islander residents (lowest quintile hazard ratio [HR], 1.85; 95% CI, 1.03-3.33), and crime index (highest quartile HR, 1.48; 95% CI, 1.08-2.03) were associated with the risk of CVD events independent of individual SES, hormone receptor status, treatment, cardiometabolic comorbidities, body mass index, and physical activity.
CONCLUSIONS
With the application of a socio-ecological framework, how residential environments shape health outcomes in women with breast cancer and affect CVD risk in this growing population can be understood.
Topics: Humans; Female; Breast Neoplasms; Cancer Survivors; Prospective Studies; Cardiovascular Diseases; Residence Characteristics
PubMed: 37096827
DOI: 10.1002/cncr.34794 -
Journal of Public Health (Oxford,... Aug 2023Loneliness is a growing public health concern, but little is known about how place affects loneliness, especially during adolescence. This is the first study to examine...
BACKGROUND
Loneliness is a growing public health concern, but little is known about how place affects loneliness, especially during adolescence. This is the first study to examine the influence of neighbourhoods on loneliness in early-to-mid adolescence.
METHODS
Baseline data from the #BeeWell cohort study in Greater Manchester (England), including 36 141 adolescents (aged 12-15 years) across 1590 neighbourhoods, were linked to neighbourhood characteristics using administrative data at the level of lower super output areas and analysed using multilevel regression.
RESULTS
Neighbourhood differences explained 1.18% of the variation in loneliness. Ethnic, gender and sexual orientation inequalities in loneliness varied across neighbourhoods. Several neighbourhood characteristics predicted loneliness at the individual level, including skills deprivation among children and young people, lower population density and perceptions of the local area (feeling safe; trust in local people; feeling supported by local people; seeing neighbours as helpful; the availability of good places to spend free time). Finally, a longer distance from home to school was associated with significantly higher loneliness.
CONCLUSIONS
Neighbourhoods account for a small but significant proportion of the variation in adolescent loneliness, with some neighbourhood characteristics predicting loneliness at the individual level, and loneliness disparities for some groups differing across neighbourhoods.
Topics: Child; Humans; Male; Adolescent; Female; Cohort Studies; Loneliness; Schools; England; Residence Characteristics; Neighborhood Characteristics; Socioeconomic Factors
PubMed: 37170940
DOI: 10.1093/pubmed/fdad053