1,993 research outputs found

    Case report : synucleinopathy associated with phalaris neurotoxicity in sheep

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    Chronic intoxication with tryptamine-alkaloid-rich Phalaris species (spp.) pasture plants is known colloquially as Phalaris staggers syndrome, a widely occurring neurological disorder of sheep, cattle, horses, and kangaroos. Of comparative interest, structurally analogous tryptamine-alkaloids cause experimental parkinsonism in primates. This study aimed to investigate the neuropathological changes associated with spontaneous cases of Phalaris staggers in sheep with respect to those encountered in human synucleinopathy. In sheep affected with Phalaris staggers, histological, immunohistochemical, and immunofluorescence analysis revealed significant accumulation of neuromelanin and aggregated α-synuclein in the perikaryon of neurons in the cerebral cortex, thalamus, brainstem, and spinal cord. Neuronal intracytoplasmic Lewy bodies inclusions were not observed in these cases of ovine Phalaris staggers. These important findings established a clear link between synucleinopathy and the neurologic form of Phalaris plant poisoning in sheep, demonstrated in six of six affected sheep. Synucleinopathy is a feature of a number of progressive and fatal neurodegenerative disorders of man and may be a common endpoint of such disorders, which in a variety of ways perturb neuronal function. However, whether primary to the degenerative process or a consequence of it awaits clarification in an appropriate model system

    Stream biasing by different induction sequences: Evaluating stream capture as an account of the segregation-promoting effects of constant-frequency inducers

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    Stream segregation for a test sequence comprising high-frequency (H) and low-frequency (L) pure tones, presented in a galloping rhythm, is much greater when preceded by a constant-frequency induction sequence matching one subset than by an inducer configured like the test sequence; this difference persists for several seconds. It has been proposed that constant-frequency inducers promote stream segregation by capturing the matching subset of test-sequence tones into an on-going, pre-established stream. This explanation was evaluated using 2-s induction sequences followed by longer test sequences (12–20 s). Listeners reported the number of streams heard throughout the test sequence. Experiment 1 used LHL– sequences and one or other subset of inducer tones was attenuated (0–24 dB in 6-dB steps, and 1). Greater attenuation usually caused a progressive increase in segregation, towards that following the constant-frequency inducer. Experiment 2 used HLH– sequences and the L inducer tones were raised or lowered in frequency relative to their test-sequence counterparts (DfI¼ 0, 0.5, 1.0, or 1.5 DfT). Either change greatly increased segregation. These results are concordant with the notion of attention switching to new sounds but contradict the stream-capture hypothesis, unless a “proto-object” corresponding to the continuing subset is assumed to form during the induction sequence

    EcoEvo-MAPS: An Ecology and Evolution Assessment for Introductory through Advanced Undergraduates

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    A new assessment tool, Ecology and Evolution–Measuring Achievement and Progression in Science or EcoEvo-MAPS, measures student thinking in ecology and evolution during an undergraduate course of study. EcoEvo-MAPS targets foundational concepts in ecology and evolution and uses a novel approach that asks students to evaluate a series of predictions, conclusions, or interpretations as likely or unlikely to be true given a specific scenario. We collected evidence of validity and reliability for EcoEvo-MAPS through an iterative process of faculty review, student interviews, and analyses of assessment data from more than 3000 students at 34 associate’s-, bachelor’s-, master’s-, and doctoral-granting institutions. The 63 likely/unlikely statements range in difficulty and target student understanding of key concepts aligned with the Vision and Change report. This assessment provides departments with a tool to measure student thinking at different time points in the curriculum and provides data that can be used to inform curricular and instructional modifications

    Ground reaction forces of Olympic and World Championship race walkers.

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    Abstract Race walking is an Olympic event where no visible loss of contact should occur and the knee must be straightened until midstance. The purpose of this study was to analyse ground reaction forces of world-class race walkers and associate them with key spatiotemporal variables. Nineteen athletes race walked along an indoor track and made contact with two force plates (1000 Hz) while being filmed using high-speed videography (100 Hz). Race walking speed was correlated with flight time (r = .46, p = .049) and flight distance (r = .69, p = .001). The knee's movement from hyperextension to flexion during late stance meant the vertical push-off force that followed midstance was smaller than the earlier loading peak (p < .001), resulting in a flattened profile. Athletes with narrower stride widths experienced reduced peak braking forces (r = .49, p = .046), peak propulsive forces (r = .54, p = .027), peak medial forces (r = .63, p = .007) and peak vertical push-off forces (r = .60, p = .011). Lower fluctuations in speed during stance were associated with higher stride frequencies (r = .69, p = .001), and highlighted the importance of avoiding too much braking in early stance. The flattened trajectory and consequential decrease in vertical propulsion might help the race walker avoid visible loss of contact (although non-visible flight times were useful in increasing stride length), while a narrow stride width was important in reducing peak forces in all three directions and could improve movement efficiency

    Dichotic integration of acoustic-phonetic information: Competition from extraneous formants increases the effect of second-formant attenuation on intelligibility

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    Differences in ear of presentation and level do not prevent effective integration of concurrent speech cues such as formant frequencies. For example, presenting the higher formants of a consonant-vowel syllable in the opposite ear to the first formant protects them from upward spread of masking, allowing them to remain effective speech cues even after substantial attenuation. This study used three-formant (F1+F2+F3) analogues of natural sentences and extended the approach to include competitive conditions. Target formants were presented dichotically (F1+F3; F2), either alone or accompanied by an extraneous competitor for F2 (i.e., F1±F2C+F3; F2) that listeners must reject to optimize recognition. F2C was created by inverting the F2 frequency contour and using the F2 amplitude contour without attenuation. In experiment 1, F2C was always absent and intelligibility was unaffected until F2 attenuation exceeded 30 dB; F2 still provided useful information at 48-dB attenuation. In experiment 2, attenuating F2 by 24 dB caused considerable loss of intelligibility when F2C was present, but had no effect in its absence. Factors likely to contribute to this interaction include informational masking from F2C acting to swamp the acoustic-phonetic information carried by F2, and interaural inhibition from F2C acting to reduce the effective level of F2

    Resources for Teaching and Assessing the Vision and Change Biology Core Concepts

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    The Vision and Change report called for the biology community to mobilize around teaching the core concepts of biology. This essay describes a collection of resources developed by several different groups that can be used to respond to the report’s call to transform undergraduate education at both the individual course and departmental levels. First, we present two frameworks that help articulate the Vision and Change core concepts, the BioCore Guide and the Conceptual Elements (CE) Framework, which can be used in mapping the core concepts onto existing curricula and designing new curricula that teach the biology core concepts. Second, we describe how the BioCore Guide and the CE Framework can be used alongside the Partnership for Undergraduate Life Sciences Education curricular rubric as a way for departments to self-assess their teaching of the core concepts. Finally, we highlight three sets of instruments that can be used to directly assess student learning of the core concepts: the Biology Card Sorting Task, the Biology Core Concept Instruments, and the Biology—Measuring Achievement and Progression in Science instruments. Approaches to using these resources independently and synergistically are discussed

    Reach, Usage, and Effectiveness of a Medicaid Patient Navigator Intervention to Increase Colorectal Cancer Screening, Cape Fear, North Carolina, 2011

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    IntroductionScreening for colorectal cancer can reduce incidence and death, but screening is underused, especially among vulnerable groups such as Medicaid patients. Effective interventions are needed to increase screening frequency. Our study consisted of a controlled trial of an intervention designed to improve colorectal cancer screening among Medicaid patients in North Carolina.MethodsThe intervention included a mailed screening reminder letter and decision aid followed by telephone support from an offsite, Medicaid-based, patient navigator. The study included 12 clinical practices, 6 as intervention practices and 6 as matched controls. Eligible patients were aged 50 years or older, covered by Medicaid, and identified from Medicaid claims data as not current with colorectal cancer screening recommendations. We reviewed Medicaid claims data at 6 months and conducted multivariate logistic regression to compare participant screening in intervention practices with participants in control practices. We controlled for sociodemographic characteristics.ResultsMost of the sample was black (53.1%) and female (57.2%); the average age was 56.5 years. On the basis of Medicaid claims, 9.2% of intervention participants (n = 22/240) had had a colorectal cancer screening at the 6-month review, compared with 7.5% of control patients (n = 13/174). The adjusted odds ratio when controlling for age, comorbidities, race, sex, and continuous Medicaid eligibility was 1.44 (95% confidence interval, 0.68–3.06). The patient navigator reached 44 participants (27.6%).ConclusionThe intervention had limited reach and little effect after 6 months on the number of participants screened. Higher-intensity interventions, such as use of practice-based navigators, may be needed to reach and improve screening rates in vulnerable populations
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