2,884 research outputs found

    Behavioral Response of Adult and Larval Wood Frogs (Lithobates sylvaticus) to a Common Road De-Icer, NaCl

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    Amphibians are highly vulnerable to aquatic pollutants. Due to the permeability of their skin and their aquatic larval stages, pollutants are easily absorbed into the body, which can have adverse effects on performance, survival, and fitness. This has prompted research on how environmental pollutants affect amphibian populations, especially road deicers such as sodium chloride (NaCl). Elevated NaCl can have a negative physiological impact on both adult and larval stages of amphibians, leading to reduced breeding success, morphological abnormalities, and even mortality. However, less is known about the behavioral responses of adults and especially larval amphibians to increased environmental salinity. Earlier studies suggested that adult wood frogs did not show any behavioral responses to varying salinity with short-term (10 min) exposure, while larvae had not been assessed. In this study, the behavioral responses of both adult and larval wood frogs, Lithobates sylvaticus, to increased salinity were studied via salinity choice trials where a control (aged tap water) and a designated salt solution were placed on opposite sides of a binary arena for 3,600 seconds. Adults spent less time in NaCl solutions with increasing salinity. The threshold for response was approximately 0.17 M (slightly hyperosmotic to internal osmotic concentrations). For tadpoles, time spent in salt solutions did not change as salinity increased (to a maximum of 0.25 M NaCl), but these results were confounded by mixing between the control and the salt solutions. There were no behavioral differences in tadpole activity level (number of moves between chambers) as salinity increased. Since increased salinity has been associated with decreased fitness, behavioral avoidance of high salinity and preference for lower saline systems could be advantageous for wood frogs. Adults could potentially select breeding sites with lower solute levels that would be beneficial to egg masses and offspring. However, this study suggests that tadpoles in a high solute habitat may not change their activity level, potentially leading to inability to select microhabitats within a system. In addition, although adult wood frogs did respond to increasing salinity, they did so slower than previously assessed species, potentially making them more susceptible to habitat degradation. This study furthers the understanding of how amphibian populations respond to salinity influxes in the wild and will help to promote better conservation efforts for species vulnerable to salt pollution

    Perceptual-gestural (mis)mapping in serial short-term memory: The impact of talker variability

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    The mechanisms underlying the poorer serial recall of talker-variable lists (e.g., alternating female–male voices) as compared with single-voice lists were examined. We tested the novel hypothesis that this talker variability effect arises from the tendency for perceptual organization to partition the list into streams based on voice such that the representation of order maps poorly onto the formation of a gestural sequence-output plan assembled in support of the reproduction of the true temporal order of the items. In line with the hypothesis, (a) the presence of a spoken lead-in designed to further promote by-voice perceptual partitioning accentuates the effect (Experiments 1 and 2); (b) the impairment is larger the greater the acoustic coherence is between nonadjacent items: Alternating-voice lists are more poorly recalled than four-voice lists (Experiment 3); and (c) talker variability combines nonadditively with phonological similarity, consistent with the view that both variables disrupt sequence output planning (Experiment 4). The results support the view that serial short-term memory performance reflects the action of sequencing processes embodied within general-purpose perceptual input-processing and gestural output-planning systems

    A Retrospective Analysis of Treatment and Clinical Outsomes among Patients with Methicillin-Susceptible \u3cem\u3eStaphlococcus aureus\u3c/em\u3e Bloodstream Isolates Possessing detecable mecA by a Commercial PCR Assay Compared to Patients with Methicillin-Resistant \u3cem\u3eStaphylococcus aureus\u3c/em\u3e Bloodstream Isolates

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    mecA-positive Staphylococcus aureus isolates phenotypically susceptible to cefoxitin (mecA-methicillin-sensitive S. aureus[MSSA]) have been identified. We describe the treatment and outcomes among patients with mecA-MSSA bloodstream infections (BSI) and MRSA BSI matched 1:1 for age, BSI origin, and BSI type (n = 17 per group). Compared to MRSA BSI patients, mecA-MSSA BSI patients more often experienced clinical failure (58.8% and 11.8%, P = 0.010), driven largely by persistent bacteremia (35.3% and 11.8%). mecA-MSSA BSI patients may be at higher risk for poor clinical outcomes

    Retrieval from memory: Vulnerable or inviolable?

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    We show that retrieval from semantic memory is vulnerable even to the mere presence of speech. Irrelevant speech impairs semantic fluency—namely, lexical retrieval cued by a semantic category name—but only if it is meaningful (forward speech compared to reversed speech or words compared to nonwords). Moreover, speech related semantically to the retrieval category is more disruptive than unrelated speech. That phonemic fluency—in which participants are cued with the first letter of words they are to report—was not disrupted by the mere presence of meaningful speech, only by speech in a related phonemic category, suggests that distraction is not mediated by executive processing load. The pattern of sensitivity to different properties of sound as a function of the type of retrieval cue is in line with an interference-by-process approach to auditory distraction

    My Rosalind:A Novel and Critical Commentary

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    Natural Selection and Its Interactions with Migration and Population Demography: Experiments in Wild Guppy Populations

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    In this dissertation I quantify spatial and temporal variation in the pattern and strength of natural selection in wild populations of Trinidadian guppies (Poecilia reticulata), and assess the demographic costs of ongoing contemporary evolution in the form of selection against migrants. First, I describe the results often mark-recapture experiments to test hypotheses concerning the role of natural selection in geographic patterns of trait variation. Previous work has reported that guppies inhabiting high- and low-predation sites differ in both body shape and color. These patterns of phenotypic variation have been theorized to reflect differences in the balance between functional trade-offs among various aspects of performance. For example, natural selection is hypothesized to disfavor bright male color (owing to predation) and sexual selection is hypothesized to favor bright color (owing to female choice). My results support some of the predictions generated from considering these functional trade-offs. However, for many color and shape traits, my results do not support the prediction that viability selection is weaker in low-predation experiments. Instead, some of the most intense bouts of selection occurred in low-predation experiments. My results illustrate considerable spatiotemporal variation in selection among experiments. It seems more complex selective interactions, possibly including the indirect effects of predators on variation in mating behavior, as well as other environmental factors, might be required to more fully explain patterns of color and shape variation in this system. Second, I quantify the demographic costs of ongoing contemporary evolution. Fine-scale genetic diversity and contemporary evolution can theoretically influence ecological dynamics in the wild. Such eco-evolutionary effects may be particularly relevant to the persistence of species facing acute or chronic environmental change. One way that ongoing evolution may influence the dynamics of threatened populations is through the role that selection plays in mediating the rescue effect , the ability of migrants to contribute to the recovery of populations facing local disturbance and decline. I combined field experiments with natural catastrophic events to show that ongoing evolution is a major determinant of migrant contributions to population recovery in Trinidadian guppies

    Pavlov Patient Database

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    This project is implementing and deploying a functional patient database with customizable treatment plans and progress notes for Choices!, a counseling service center. To build this application and support the various requirements, several frameworks were considered for this project including Django, Flask, and Ruby on Rails. The Ruby on Rails suite was selected for reasons of existing familiarity for the team. Existing libraries within Rails allow for a choice of several database engines; MySQL, Postgresql, MongoDB, and NoSQL were considered. MySQL was adopted as a result of the extensive documentation and for continuity with the previous solution. Front-end requirements were met with a combination of HTML and Javascript, linked to a Bootstrap 5 framework in order to streamline user accessibility. A key quality desired by the customer was ease-of-use, to encourage higher efficiency and easy adoption by the stakeholders. In the process of development, secure data handling also emerged as a further and highly-desired attribute
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