332 research outputs found

    Predicting College Student Gambling Frequency Using the Theory of Planned Behvior: Does the Theory Work Differently for Disordered and Non-Disordered Gamblers?

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    We examined whether disordered gambling moderates the prediction of gambling behavior via the theory of planned behavior (TPB; i.e., intentions, subjective norms, perceived behavioral control, and attitudes) among college students. A convenience sample of undergraduate students (N=377) at a large, Southeastern university who gambled in the past year completed a classroom-based survey. Approximately half of participants were male (n = 205; 54.4%), and the majority were Caucasian (n = 310; 83.8%). Gambling frequency, gambling problems and gambling-specific TPB constructs were assessed via a cross-sectional survey. A series of regression analyses were conducted to test the utility of the TPB model to predict gambling behavior (i.e., frequency) among (1) non-disordered gamblers (N=342) and (2) disordered gamblers (N=35). Moderation analyses indicated that disordered gamblers might not proceed through the thought processes that guide gambling in non-disordered gamblers. However, findings should be interpreted cautiously, as our study was limited by a small number of lifetime disordered gamblers

    Event-Driven Environmental News in the U.S. and Canada

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    This paper presents results from a content analytic study of U.S. and Canadian evening news programs on energy and environmental topics from 1999 to 2009. The analysis reveals the importance of coverage of weather and natural disasters in both countries — importance not just in terms of the volume of coverage, but in the role that coverage plays in driving discussion of broader, more thematic coverage of pollution and climate change. Indeed, causality tests reveal that coverage of climate change, pollution and related issues are strongly affected by — or, rather, dependent on — coverage of disasters and other weather events

    Spatial Heterogeneity in Soil Microbes Alters Outcomes of Plant Competition

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    Plant species vary greatly in their responsiveness to nutritional soil mutualists, such as mycorrhizal fungi and rhizobia, and this responsiveness is associated with a trade-off in allocation to root structures for resource uptake. As a result, the outcome of plant competition can change with the density of mutualists, with microbe-responsive plant species having high competitive ability when mutualists are abundant and non-responsive plants having high competitive ability with low densities of mutualists. When responsive plant species also allow mutualists to grow to greater densities, changes in mutualist density can generate a positive feedback, reinforcing an initial advantage to either plant type. We study a model of mutualist-mediated competition to understand outcomes of plant-plant interactions within a patchy environment. We find that a microbe-responsive plant can exclude a non-responsive plant from some initial conditions, but it must do so across the landscape including in the microbe-free areas where it is a poorer competitor. Otherwise, the non-responsive plant will persist in both mutualist-free and mutualist-rich regions. We apply our general findings to two different biological scenarios: invasion of a non-responsive plant into an established microbe-responsive native population, and successional replacement of non-responders by microbe-responsive species. We find that resistance to invasion is greatest when seed dispersal by the native plant is modest and dispersal by the invader is greater. Nonetheless, a native plant that relies on microbial mutualists for competitive dominance may be particularly vulnerable to invasion because any disturbance that temporarily reduces its density or that of the mutualist creates a window for a non-responsive invader to establish dominance. We further find that the positive feedbacks from associations with beneficial soil microbes create resistance to successional turnover. Our theoretical results constitute an important first step toward developing a general understanding of the interplay between mutualism and competition in patchy landscapes, and generate qualitative predictions that may be tested in future empirical studies

    Pramlintide but Not Liraglutide Suppresses Meal-Stimulated Glucagon Responses in Type 1 Diabetes

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    Postprandial hyperglycemia remains a challenge in type 1 diabetes (T1D) due, in part, to dysregulated increases in plasma glucagon levels after meals

    Suprarenal aortic clamping and reperfusion decreases medullary and cortical blood flow by decreased endogenous renal nitric oxide and PGE2 synthesis

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    ObjectiveThis study examined the hypothesis that clamping the aorta above the superior mesenteric artery (SMA) followed by suprarenal aortic clamping and reperfusion (SRACR) decreases microvascular blood flow by loss of endogenous medullary and cortical nitric oxide (NO) and prostaglandin (PG) E2 synthesis.Study DesignAnesthetized male Sprague-Dawley rats (350 g) had either microdialysis probes or laser Doppler fibers inserted into the renal cortex to a depth of 2 mm and into the renal medulla at 4 mm. Laser Doppler blood flow was continuously monitored (data reported as percentage of change compared to basal), and the microdialysis probes were connected to a syringe pump and perfused in vivo at 3 μL/min with lactated Ringer solution. Dialysate fluid was collected at basal time zero, following 30 minutes of suprarenal aortic clamping (ischemia) followed by 60 minutes of reperfusion and compared to a sham operation. Both groups were treated with saline carrier, indomethacin (INDO) (10 mg/kg, a cyclooxygenase [COX] inhibitor), NG-nitro-l-arginine methyl ester (l-NAME) (20 mg/kg, a NO synthase [NOS] inhibitor), or l-arginine (200 mg/kg, an NO precursor). Dialysate was analyzed for total NO (μM) and PGE2 (pg/mL) synthesis. The renal cortex and medulla were analyzed for inducible NOS (iNOS) and COX-2 content by Western blot. All data are reported as mean ± SEM, N > 5 and analyzed by analysis of variance.ResultsSRACR caused a marked decrease in medullary and cortical blood flow with a concomitant decrease in endogenous medullary and cortical NO synthesis. Treatment with l-NAME further decreased blood flow and NO synthesis in the medulla and cortex. l-Arginine restored medullary and cortical NO synthesis and blood flow in the cortex but not the medulla. SRACR did not alter renal medullary or cortical PGE2; however, addition of INDO, COX inhibitor, caused a concomitant decrease in medullary and cortical PGE2 synthesis and blood flow.ConclusionsNO is an important endogenous renal vasodilator that, when maintained can help preserve cortical blood flow following SRACR. These data also suggest that avoidance of COX-2 inhibitors can help maintain endogenous renal cortical and medullary PGE2 synthesis and thus contribute to maintaining normal blood flow.Clinical RelevanceThis study is the first to combine in vivo physiologic assays to simultaneously identify clinically relevant intrarenal vasodilators (cortical and medullary) that are required to maintain microvascular blood flow. Identification of endogenous renal cortical and medullary vasodilators responsible for maintaining renal microvascular blood flow will allow development of treatment strategies to preserve these vasodilators following SRACR. Successful preservation of endogenous intrarenal vasodilators will help maintain renal microvascular blood flow and renal function in the treatment of complex aortic pathology that requires SRACR

    UNSWIRF: A Tunable Imaging Spectrometer for the Near-Infrared

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    We describe the specifications, characteristics, calibration, and analysis of data from the University of New South Wales Infrared Fabry-Perot (UNSWIRF) etalon. UNSWIRF is a near-infrared tunable imaging spectrometer, used primarily in conjunction with IRIS on the AAT, but suitable for use as a visitor instrument at other telescopes. The etalon delivers a resolving power in excess of 4000 (corresponding to a velocity resolution ~75 km/s), and allows imaging of fields up to 100" in diameter on the AAT at any wavelength between 1.5 and 2.4 microns for which suitable blocking filters are available.Comment: 16 pages, 10 figures, uses psfig.sty and html.sty (included). To appear in Publications of the Astronomical Society of Australi

    Effects of bracing in adolescents with idiopathic scoliosis

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    BACKGROUND: The role of bracing in patients with adolescent idiopathic scoliosis who are at risk for curve progression and eventual surgery is controversial. METHODS: We conducted a multicenter study that included patients with typical indications for bracing due to their age, skeletal immaturity, and degree of scoliosis. Both a randomized cohort and a preference cohort were enrolled. Of 242 patients included in the analysis, 116 were randomly assigned to bracing or observation, and 126 chose between bracing and observation. Patients in the bracing group were instructed to wear the brace at least 18 hours per day. The primary outcomes were curve progression to 50 degrees or more (treatment failure) and skeletal maturity without this degree of curve progression (treatment success). RESULTS: The trial was stopped early owing to the efficacy of bracing. In an analysis that included both the randomized and preference cohorts, the rate of treatment success was 72% after bracing, as compared with 48% after observation (propensity-score–adjusted odds ratio for treatment success, 1.93; 95% confidence interval [CI], 1.08 to 3.46). In the intention-to-treat analysis, the rate of treatment success was 75% among patients randomly assigned to bracing, as compared with 42% among those randomly assigned to observation (odds ratio, 4.11; 95% CI, 1.85 to 9.16). There was a significant positive association between hours of brace wear and rate of treatment success (P CONCLUSIONS: Bracing significantly decreased the progression of high-risk curves to the threshold for surgery in patients with adolescent idiopathic scoliosis. The benefit increased with longer hours of brace wear. (Funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases and others; BRAIST ClinicalTrials.gov number, NCT00448448opens in new tab.)</p

    To brace or not? The answer is “it depends”. Preliminary results from BrAIST

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    Improving the Accuracy of Predicting Maximal Oxygen Consumption (VO2pk)

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    Maximal oxygen (VO2pk) is the maximum amount of oxygen that the body can use during intense exercise and is used for benchmarking endurance exercise capacity. The most accurate method to determineVO2pk requires continuous measurements of ventilation and gas exchange during an exercise test to maximal effort, which necessitates expensive equipment, a trained staff, and time to set-up the equipment. For astronauts, accurate VO2pk measures are important to assess mission critical task performance capabilities and to prescribe exercise intensities to optimize performance. Currently, astronauts perform submaximal exercise tests during flight to predict VO2pk; however, while submaximal VO2pk prediction equations provide reliable estimates of mean VO2pk for populations, they can be unacceptably inaccurate for a given individual. The error in current predictions and logistical limitations of measuring VO2pk, particularly during spaceflight, highlights the need for improved estimation methods
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