275 research outputs found

    The Dynamics of Preschoolers' Categorization Choices

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    The role of landscape history in determining allelic richness of European ground squirrels (Spermophilus citellus) in Central Europe

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    Genetic diversity is of paramount importance for individual fitness and evolutionary potential of populations. For conservation planning it is crucial to know how genetically diverse a species is and what factors may explain variation of genetic diversity among populations. Our aim was to evaluate the effects of landscape history, ecological isolation, and local population size on allelic richness of local populations in European ground squirrels (Spermophiluscitellus). We genotyped 144 individuals from nine local populations collected in two neighbouring regions with decades of different landscape history. We assessed allelic richness, ecological isolation and local population size by eleven polymorphic microsatellites, the isolation index of Rodríguez and Delibes,and standardised counts of burrows openings, respectively. Statistical models indicated a strong effect of landscape history on allelic richness of local populations. Ecological isolation of local populations apparently played only a marginal role, and local population size was an unimportant factor. Our modelling results highlight the dominant role of landscape history for the genetic diversity of S. citellus. The strong landscape history effect encountered presently includes a different region-specific socio-economic development due to distinct agricultural systems in the two regions, especially after World War II. Levels of ecological isolation of local populations have diverged in an extent too small to explain variation of local allelic richness. The lack of significant effect of local population size suggests that census sizes of the populations studied are all not critically low. Moreover,census and estimated effective population sizes were not closely related. Establishing corridors or translocating S. citellus in the species’ historical range should be encouraged to promote gene flow between local populations and counteract the loss of genetic diversity by drift, provided that no conflicting factors (ecological, epidemiological, etc.) exist

    Early Domain-Specific Knowledge? Nonlinear Developmental Trajectories Further Erode a House of Sand

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    Rakison and Yermolayeva (this issue) argue that domain specificity is difficult to reconcile with U-, N-, or M-shaped developmental trends. They are justified because: 1) There is no compelling evidence that nonlinear trends require mechanisms beyond general, well-known cognitive processes; and 2) epigenetic neuroscience provides no clear evidence of strong domain-specialized representations. Evidence implies pervasive weak (i.e., experience dependent) neural specialization for different kinds of information. © 2011 Taylor & Francis Group, LLC

    Intensity of Caring About an Action’s Side-Effect Mediates Attributions of Actor’s Intentions

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    The side-effect effect (SEE) is the observation that people’s intuition about whether an action was intentional depends on whether the outcome is good or bad. The asymmetric response, however, does not represent all subjects’ judgments (Nichols and Ulatowski, 2007). It remains unexplored on subjective factors that can mediate the size of SEE. Thus, the current study investigated whether an individual related factor, specifically, whether adults’ intensity of caring about an outcome of someone’s actions influences their judgments about whether that person intended the outcome. We hypothesized that participants’ judgments about fictional agents’ responsibility for their action’s side-effects would depend on how much they care about the domain of the side-effect. In two experiments, the intensity of caring affected participants’ ascription of intention to an agent’s negative unintended side-effect. The stronger ascription of intentionality to negative than positive side-effects (i.e., the SEE; Knobe, 2003) was found only in domains in which participants reported higher levels of caring. Also, the intensity of caring increased intentionality attributions reliably for negative side-effects but not for positive side-effects. These results suggest that caring about a domain mediates an asymmetrical ascription of intentionality to negative more than positive side-effects

    A supersonic crowdion in mica: Ultradiscrete kinks with energy between 40^{40}K recoil and transmission sputtering

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    In this chapter we analyze in detail the behaviour and properties of the kinks found in an one dimensional model for the close packed rows of potassium ions in mica muscovite. The model includes realistic potentials obtained from the physics of the problem, ion bombardment experiments and molecular dynamics fitted to experiments. These kinks are supersonic and have an unique velocity and energy. They are ultradiscrete involving the translation of an interstitial ion, which is the reason they are called 'crowdions'. Their energy is below the most probable source of energy, the decay of the 40^{40}K isotope and above the energy needed to eject an atom from the mineral, a phenomenon that has been observed experimentallyComment: 28 pages, 15 figure

    Young children's flexible use of semantic cues to word meanings: converging evidence of individual and age differences

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    A new test of children’s flexible use of semantic cues for word learning extended previous results. In Experiment 1, three- to five-year-olds (N=51) completed two tests of interpreting several novel words for the same stimulus arrays. Within-sentence phrasal cues implied different stimulus referent properties. Children’s cue-using flexibility in the new Flexible Induction of Meanings [Words for Animates] test (FIM-An) was strongly correlated with an established test (Flexible Induction of Meanings [Words for Objects] ; Deak, 2000). Individual children showed between-test consistency in using cues to flexibly assign words to different referent properties. There were large individual differences, as well as limited age differences, in the distribution of flexible and inflexible response patterns. The comprehensibility of specific cues, and perceptual salience of specific properties, explained much of the variance. Proportions of flexible and inflexible patterns shifted with age. Experiment 2 replicated these results in N=36 three- and four-year-olds, using a modified FIM-An with more distinctive cues

    Evaluation of light microscopy and rapid diagnostic test for the detection of malaria under operational field conditions: a household survey in Ethiopia.

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    BACKGROUND: In most resource-poor settings, malaria is usually diagnosed based on clinical signs and symptoms and not by detection of parasites in the blood using microscopy or rapid diagnostic tests (RDT). In population-based malaria surveys, accurate diagnosis is important: microscopy provides the gold standard, whilst RDTs allow immediate findings and treatment. The concordance between RDTs and microscopy in low or unstable transmission areas has not been evaluated. OBJECTIVES: This study aimed to estimate the prevalence of malaria parasites in randomly selected malarious areas of Amhara, Oromia, and Southern Nations, Nationalities and Peoples' (SNNP) regions of Ethiopia, using microscopy and RDT, and to investigate the agreement between microscopy and RDT under field conditions. METHODS: A population-based survey was conducted in 224 randomly selected clusters of 25 households each in Amhara, Oromia and SNNP regions, between December 2006 and February 2007. Fingerpick blood samples from all persons living in even-numbered households were tested using two methods: light microscopy of Giemsa-stained blood slides; and RDT (ParaScreen device for Pan/Pf). RESULTS: A total of 13,960 people were eligible for malaria parasite testing of whom 11,504 (82%) were included in the analysis. Overall slide positivity rate was 4.1% (95% confidence interval [CI] 3.4-5.0%) while ParaScreen RDT was positive in 3.3% (95% CI 2.6-4.1%) of those tested. Considering microscopy as the gold standard, ParaScreen RDT exhibited high specificity (98.5%; 95% CI 98.3-98.7) and moderate sensitivity (47.5%; 95% CI 42.8-52.2) with a positive predictive value of 56.8% (95% CI 51.7-61.9) and negative predictive value of 97.6% (95% CI 97.6-98.1%) under field conditions. CONCLUSION: Blood slide microscopy remains the preferred option for population-based prevalence surveys of malaria parasitaemia. The level of agreement between microscopy and RDT warrants further investigation in different transmission settings and in the clinical situation
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