274 research outputs found

    Trophic Garnishes: Cat–Rat Interactions in an Urban Environment

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    BACKGROUND:Community interactions can produce complex dynamics with counterintuitive responses. Synanthropic community members are of increasing practical interest for their effects on biodiversity and public health. Most studies incorporating introduced species have been performed on islands where they may pose a risk to the native fauna. Few have examined their interactions in urban environments where they represent the majority of species. We characterized house cat (Felis catus) predation on wild Norway rats (Rattus norvegicus), and its population effects in an urban area as a model system. Three aspects of predation likely to influence population dynamics were examined; the stratum of the prey population killed by predators, the intensity of the predation, and the size of the predator population. METHODOLOGY/PRINCIPAL FINDINGS:Predation pressure was estimated from the sizes of the rat and cat populations, and the characteristics of rats killed in 20 alleys. Short and long term responses of rat population to perturbations were examined by removal trapping. Perturbations removed an average of 56% of the rats/alley but had no negative long-term impact on the size of the rat population (49.6+/-12.5 rats/alley and 123.8+/-42.2 rats/alley over two years). The sizes of the cat population during two years (3.5 animals/alley and 2.7 animals/alley) also were unaffected by rat population perturbations. Predation by cats occurred in 9/20 alleys. Predated rats were predominantly juveniles and significantly smaller (144.6 g+/-17.8 g) than the trapped rats (385.0 g+/-135.6 g). Cats rarely preyed on the larger, older portion of the rat population. CONCLUSIONS/SIGNIFICANCE:The rat population appears resilient to perturbation from even substantial population reduction using targeted removal. In this area there is a relatively low population density of cats and they only occasionally prey on the rat population. This occasional predation primarily removes the juvenile proportion of the rat population. The top predator in this urban ecosystem appears to have little impact on the size of the prey population, and similarly, reduction in rat populations doesn't impact the size of the cat population. However, the selected targeting of small rats may locally influence the size structure of the population which may have consequences for patterns of pathogen transmission

    Dunno if you've any plans for the future: medical student indirect questioning in simulated oncology interviews

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    <p>Abstract</p> <p>Background</p> <p>This exploratory study investigated the motives of medical students (N = 63) for using indirect questions of the type <it>I don't know if </it>[you have already heard about chemotherapies], <it>I don't know how </it>[you are], or <it>I don't know what </it>[you do for a living] in simulated patient interviews during a communication skills course.</p> <p>Methods</p> <p><it>I don't know </it>questions (IDK-Qs) were observed during the initial evaluation of students' communication skills; they were systematically identified through video screening and subjected to a qualitative content and discourse analysis considering their context, their content, their intent and their effect on the simulated patients. To evaluate the specificity of medical students' IDK-Qs, the data were compared with a data set of oncologists (N = 31) conducting simulated patient interviews in the context of a Communication Skills Training (CST).</p> <p>Results</p> <p>During the interviews, 41.3% of the students asked 1-6 IDK-Qs. The IDK-Qs were attributed to three content categories: medical/treatment questions (N = 24); lifestyle/psychosocial questions (N = 18); and "inviting questions" questions (N = 11). Most of the IDK-Qs had an exploratory function (46/53), with simulated patients providing detailed responses or asking for more information (36/53). IDK-Qs were rare in the oncologist sample compared to the student sample (5 vs. 53 occurrences).</p> <p>Conclusions</p> <p>IDK-Qs showed a question design difference between medical students and oncologists in simulated patient interviews. Among other reasons for this difference, the possible function of IDK-Qs as a protective linguistic strategy and marker for psychological discomfort is discussed.</p
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