Why We Can't Wait.
Ontology highlight
ABSTRACT:
SUBMITTER: Solola J
PROVIDER: S-EPMC7901623 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Two-sex populations are usually studied through frequency-dependent models that describe how sex ratio affects mating, recruitment and population growth. However, in two-sex populations, mating and recruitment should also be affected by density and by its interactions with the sex ratio. Density may have positive effects on mating (Allee effects) but negative effects on other demographic processes. In this study, we quantified how positive and negative inter-sexual interactions balance in two-sex populations. Using a dioecious grass (Poa arachnifera), we established experimental field populations that varied in density and sex ratio. We then quantified mating success (seed fertilization) and non-mating demographic performance, and integrated these responses to project population-level recruitment. Female mating success was positively density-dependent, especially at female-biased sex ratios. Other demographic processes were negatively density-dependent and, in some cases, frequency-dependent. Integrating our experimental results showed that mate-finding Allee effects dominated other types of density-dependence, giving rise to recruitment that increased with increasing density and peaked at intermediate sex ratios, reflecting tension between seed initiation (greater with more females) and seed viability (greater with more males). Our results reveal, for the first time, the balance of positive and negative inter-sexual interactions in sex-structured populations. Models that account for both density- and sex ratio dependence, particularly in mating, may be necessary for understanding and predicting two-sex population dynamics.
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Project description:The COVID-19 outbreak and related public health guidelines have changed the daily lives of Canadians and restricted opportunities for healthy movement behaviours for children. The purpose of this study was to explore how parents experienced the pandemic-related restrictions and how they impacted their children's movement behaviours. Methods: Twenty-nine semi-structured one-on-one interviews were conducted (June-July 2020) with parents of children (5-11 years old) in Ontario and British Columbia. Interviews lasted between 24-104 min, were audio-recorded, transcribed verbatim, and thematically analyzed. Results: Findings emphasized various individual (e.g., motivation), interpersonal (e.g., parent work schedule), built (e.g., closure of parks) and natural environment (e.g., weather) factors related to children's movement behaviours. The findings highlighted the loss of structured activities and destinations for children's physical activity, and restricted opportunities for outdoor play exacerbated by shrinking childhood independent mobility. Conclusion: Families are adapting to many pandemic-related challenges including adhering to public health restrictions, parents juggling multiple roles, conducting work and school from home, as well as exacerbating factors like weather. It will be important to continue to encourage outdoor time, support policies and practice that facilitate independent mobility, and develop centralized resources that help families in the maintenance of healthy movement behaviours.
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Project description:eLife editors and reviewers consult with one another before sending out a decision after peer review. This means that authors do not have to spend time responding to confusing or conflicting requests for revisions.
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Project description:Objective: We analyzed changes in A. fumigatus gene expression profile at various stages of an in vitro model of aspergillosis to study the adaptation of A. fumigatus to the blood environment. Results: Most of virulence factors described to be involved in aspergillosis were not activated during the blood phase. We found three active processes to be activated in the later phase that may help to the adaptation: Iron homeostasis, a partial secondary metabolite cluster and the formation of detoxification enzymes. Conclusions: We propose that A. fumigatus is unable to grow in blood and it requires a metabolic change that allows the organism to shut down all uptake and energy-consume mechanisms, resulting in a resting mycelial stage.
2015-11-24 | GSE70227 | GEO
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Project description:We lack a comprehensive understanding of evolutionary pattern and process because short-term and long-term data have rarely been combined into a single analytical framework. Here we test alternative models of phenotypic evolution using a dataset of unprecedented size and temporal span (over 8,000 data points). The data are body-size measurements taken from historical studies, the fossil record, and among-species comparative data representing mammals, squamates, and birds. By analyzing this large dataset, we identify stochastic models that can explain evolutionary patterns on both short and long timescales and reveal a remarkably consistent pattern in the timing of divergence across taxonomic groups. Even though rapid, short-term evolution often occurs in intervals shorter than 1 Myr, the changes are constrained and do not accumulate over time. Over longer intervals (1-360 Myr), this pattern of bounded evolution yields to a pattern of increasing divergence with time. The best-fitting model to explain this pattern is a model that combines rare but substantial bursts of phenotypic change with bounded fluctuations on shorter timescales. We suggest that these rare bursts reflect permanent changes in adaptive zones, whereas the short-term fluctuations represent local variations in niche optima due to restricted environmental variation within a stable adaptive zone.
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Project description:Many scientists agree that expertise requires both innate talent and proper training. Nevertheless, the highly influential deliberate practice model (DPM) of expertise holds that talent does not exist or makes a negligible contribution to performance. It predicts that initial performance will be unrelated to achieving expertise and that 10 years of deliberate practice is necessary. We tested these predictions in the domain of sprinting. In Studies 1 and 2 we reviewed biographies of 15 Olympic champions and the 20 fastest American men in U.S. history. In all documented cases, sprinters were exceptional prior to initiating training, and most reached world class status rapidly (Study 1 median = 3 years; Study 2 = 7.5). In Study 3 we surveyed U.S. national collegiate championships qualifiers in sprinters (n = 20) and throwers (n = 44). Sprinters recalled being faster as youths than did throwers, whereas throwers recalled greater strength and throwing ability. Sprinters' best performances in their first season of high school, generally the onset of formal training, were consistently faster than 95-99% of their peers. Collectively, these results falsify the DPM for sprinting. Because speed is foundational for many sports, they challenge the DPM generally.
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