65 research outputs found

    Fast life history traits promote invasion success in amphibians and reptiles

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    Competing theoretical models make different predictions on which life history strategies facilitate growth of small populations. While ā€˜fastā€™ strategies allow for rapid increase in population size and limit vulnerability to stochastic events, ā€˜slowā€™ strategies and bet-hedging may reduce variance in vital rates in response to stochasticity. We test these predictions using biological invasions since founder alien populations start small, compiling the largest dataset yet of global herpetological introductions and life history traits. Using state-of-the-art phylogenetic comparative methods, we show that successful invaders have fast traits, such as large and frequent clutches, at both establishment and spread stages. These results, together with recent findings in mammals and plants, support ā€˜fast advantageā€™ models and the importance of high potential population growth rate. Conversely, successful alien birds are bet-hedgers. We propose that transient population dynamics and differences in longevity and behavioural flexibility can help reconcile apparently contrasting results across terrestrial vertebrate classes

    Hydrology and climatology at Laguna La Gaiba, lowland Bolivia: complex responses to climatic forcings over the last 25,000 years

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    Diatom, geochemical and isotopic data provide a record of environmental change in Laguna La Gaiba, lowland Bolivia, over the last ca. 25 000 years. High-resolution diatom analysis around the last glacialā€“interglacial transition provides new insights into this period of change. The full and late glacial lake was generally quite shallow, but with evidence of periodic flooding. At about 13,100 cal a BP, just before the start of the Younger Dryas chronozone, the diatoms indicate shallower water conditions, but there is a marked change at about 12,200 cal a BP indicating the onset of a period of high variability, with rising water levels punctuated by periodic drying. From ca. 11,800 to 10,000 cal a BP stable, deeper water conditions persisted. There is evidence for drying in the early to middle Holocene, but not as pronounced as that reported from elsewhere in the southern hemisphere tropics of South America. This was followed by the onset of wetter conditions in the late Holocene consistent with insolation forcing. Conditions very similar to present were established about 2,100 cal a BP. A complex response to both insolation forcing and millennial scale events originating in the North Atlantic is noted

    The Capaciousness of No: Affective Refusals as Literacy Practices

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    Ā© 2020 The Authors. Reading Research Quarterly published by Wiley Periodicals, Inc. on behalf of International Literacy Association The authors considered the capacious feeling that emerges from saying no to literacy practices, and the affective potential of saying no as a literacy practice. The authors highlight the affective possibilities of saying no to normative understandings of literacy, thinking with a series of vignettes in which children, young people, and teachers refused literacy practices in different ways. The authors use the term capacious to signal possibilities that are as yet unthought: a sense of broadening and opening out through enacting no. The authors examined how attention to affect ruptures humanist logics that inform normative approaches to literacy. Through attention to nonconscious, noncognitive, and transindividual bodily forces and capacities, affect deprivileges the human as the sole agent in an interaction, thus disrupting measurements of who counts as a literate subject and what counts as a literacy event. No is an affective moment. It can signal a pushback, an absence, or a silence. As a theoretical and methodological way of thinking/feeling with literacy, affect proposes problems rather than solutions, countering solution-focused research in which the resistance is to be overcome, co-opted, or solved. Affect operates as a crack or a chink, a tiny ripple, a barely perceivable gesture, that can persist and, in doing so, hold open the possibility for alternative futures

    The H4K20 demethylase DPY-21 regulates the dynamics of condensin DC binding

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    Condensin is a multi-subunit SMC complex that binds to and compacts chromosomes. Unlike cohesin, in vivo regulators of condensin binding dynamics remain unclear. Here we addressed this question using C. elegans condensin DC, which specifically binds to and represses transcription of both X chromosomes in hermaphrodites for dosage compensation. Mutants of several chromatin modifiers that regulate H4K20me and H4K16ac cause varying degrees of X chromosome derepression. We used fluorescence recovery after photobleaching (FRAP) to analyze how these modifiers regulate condensin DC binding dynamics in vivo. We established FRAP using the SMC4 homolog DPY-27 and showed that a well-characterized ATPase mutation abolishes its binding. The greatest effect on condensin DC dynamics was in a null mutant of the H4K20me2 demethylase DPY-21, where the mobile fraction of the complex reduced from āˆ¼30% to 10%. In contrast, a catalytic mutant of dpy-21 did not regulate condensin DC mobility. Separation of catalytic and non-catalytic activity is also supported by Hi-C data in the dpy-21 null mutant. Together, our results indicate that DPY-21 has a non-catalytic role in regulating the dynamics of condensin DC binding, which is important for transcription repression

    The H4K20 demethylase DPY-21 regulates the dynamics of condensin DC binding

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    Condensin is a multi-subunit SMC complex that binds to and compacts chromosomes. Here we addressed the regulation of condensin binding dynamics using C. elegans condensin DC, which represses X chromosomes in hermaphrodites for dosage compensation. We established fluorescence recovery after photobleaching (FRAP) using the SMC4 homolog DPY-27 and showed that a well-characterized ATPase mutation abolishes its binding. Next, we performed FRAP in the background of several chromatin modifier mutants that cause varying degrees of X-chromosome derepression. The greatest effect was in a null mutant of the H4K20me2 demethylase DPY-21, where the mobile fraction of condensin DC reduced from āˆ¼30% to 10%. In contrast, a catalytic mutant of dpy-21 did not regulate condensin DC mobility. Hi-C data in the dpy-21 null mutant showed little change compared to wild type, uncoupling Hi-C measured long-range DNA contacts from transcriptional repression of the X chromosomes. Together, our results indicate that DPY-21 has a non-catalytic role in regulating the dynamics of condensin DC binding, which is important for transcription repression

    Training of adult psychiatrists and child and adolescent psychiatrists in europe

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    Background: Profound clinical, conceptual and ideological differences between child and adult mental health service models contribute to transition-related discontinuity of care. Many of these may be related to psychiatry training. Methods: A systematic review on General Adult Psychiatry (GAP) and Child and Adult Psychiatry (CAP) training in Europe, with a particular focus on transition as a theme in GAP and CAP training. Results: Thirty-four full-papers, six abstracts and seven additional full text documents were identified. Important variations between countries were found across several domains including assessment of trainees, clinical and educational supervision, psychotherapy training and continuing medical education. Three models of training were identified: i) a generalist common training programme; ii) totally separate training programmes; iii) mixed types. Only two national training programs (UK and Ireland) were identified to have addressed transition as a topic, both involving CAP exclusively. Conclusion: Three models of training in GAP and CAP across Europe are identified, suggesting that the harmonization is not yet realised and a possible barrier to improving transitional care. Training in transition has only recently been considered. It is timely, topical and important to develop evidence-based training approaches on transitional care across Europe into both CAP and GAP training

    Exaggerated sexual swellings in female nonhuman primates are reliable signals of female fertility and body condition

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    In some species of Old World monkeys and apes, females exhibit exaggerated swellings of the anogenital region that vary in size across the ovarian cycle. Exaggerated swellings are typically largest around the time of ovulation, and swelling size has been reported to correlate positively with female quality, supporting the hypothesis that exaggerated swellings are honest signals of both female fecundity and quality. However, the relationship between swelling size and timing of ovulation is weak in some studies, and the relationship between swelling size and female quality has also not been consistently reported. Here, we collated empirical studies that have reported either swelling size and estimated timing of ovulation (N = 26) or swelling size and measures of individual quality (N = 7), to assess the strength of these relationships using meta-analytical methods. Our analyses confirmed that the period of maximal swelling size is closely associated with the most fertile period of the ovarian cycle and that a large proportion of ovulations occur during the maximal swelling period. A small, positive effect size was also found for the relationship between swelling size and body condition. In contrast, the relationships with age and social rank were not significant. Swelling size, therefore, potentially signals both female condition and timing of the fertile phase. Males are likely to benefit from allocating mating effort according to swelling size, while females with large swellings potentially benefit from exerting control over matings in species in which female control is compromised by male mating strategies

    The evolution of cerebellum structure correlates with nest complexity

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    Across the brains of different bird species, the cerebellum varies greatly in the amount of surface folding (foliation). The degree of cerebellar foliation is thought to correlate positively with the processing capacity of the cerebellum, supporting complex motor abilities, particularly manipulative skills. Here, we tested this hypothesis by investigating the relationship between cerebellar foliation and species-typical nest structure in birds. Increasing complexity of nest structure is a measure of a bird's ability to manipulate nesting material into the required shape. Consistent with our hypothesis, avian cerebellar foliation increases as the complexity of the nest built increases, setting the scene for the exploration of nest building at the neural level

    The role of population size in folk tune complexity (preprint)

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    A positive correlation between population size and cultural complexity is perhaps one of the most consistent findings in the field of cultural evolution. However, previous findings are largely based on studies of technology and are not necessarily generalisable across diverse cultural domains. We investigate the relationship between population size and complexity in music using Irish folk session tunes as a case study. Using analyses of a large online folk tune dataset, we show that tunes played by larger communities of musicians have diversified into a greater number of different versions but are intermediate in melodic complexity. These results suggest that while larger populations create more frequent opportunities for musical innovation, they encourage convergence upon intermediate levels of melodic complexity due to a widespread inverse U-shaped relationship between complexity and aesthetic preference. Our results show that the relationship between population size and cultural complexity is domain-dependent, rather than universal
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