1,293 research outputs found

    Examining the psychometric properties of the Behavioral Regulation in Exercise Questionnaire

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    The purpose of this study was to examine select psychometric properties of the Behavioral Regulation in Exercise Questionnaire (BREQ; Mullen, Markland, & Ingledew, 1997). To accomplish this aim, data were gathered in 2 phases to evaluate the BREQ’s factorial composition and structure and the relation between the BREQ, need satisfaction, exercise behavior, and relevant motivational constructs. Participants completed measures assessing psychological need satisfaction, optimism, perceived behavioral control, exercise behavior, and the BREQ. Phase 1 results supported the original 4-factor measurement model and a simplex model of structural relations between latentBREQconstructs suggested within self-determination theory (Deci & Ryan, 1985), and results supported the positive relations between more self-determined motives and greater psychological need satisfaction and frequent exercise behavior. Phase 2 results provided further construct validity evidence for the BREQ by linking subscale scores with greater perceived behavioral control in a manner consistent with theory (Deci & Ryan, 1985). Collectively, these results further support the construct validity of the BREQ and lend credence to the notion of measuring exercise motivation from a multidimensional perspective using self-determination theory as a guiding framework in the exercise domain

    What Makes a Leader: Examining How Search Committees Conceptualize, Measure, and Evaluate Leadership

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    Indiana University-Purdue University Indianapolis (IUPUI)The purpose of this research was to investigate the social and cultural constructions of leadership and how search committee members evaluate candidates for leadership positions. Moreover, how they conceptualize, measure, and evaluate leadership potential of candidates. To explore this issue, the following research questioned were answered: How do members of an executive search committee construct their views of leadership?; In what ways do the individual, social, and cultural constructions of leadership held by search committee members influence behaviors and outcomes of a search committee? In this study, I investigated how members of a search committee constructed their views of leadership and in turn how this influenced the search process for an executive leader. In order to explore this issue, this study is approached through the constructivism paradigm and informed by critical inquiry, using case study methodology. I followed one executive search process from the charge meeting until the committee made its recommendation to the hiring authority. The unit analyzed in this search employed a leadership competency model and tools which mapped to this model, in an effort to mitigate the influence of bias. I used semi-structured interviews with committee members to understand their views on leadership. I supplemented interviews with observations and document analysis as means of collecting data for the study. Three findings emerged through data analysis: the role of background and identity on views of leadership, the influence of personal and societal constructions of leadership on individual behaviors and search outcomes, and the application or utility of using a leadership competency model. Through my findings, I demonstrated how individual’s background and identity shaped their perceptions of what it meant to be a leader. Additionally, how they rated and talked about candidates matched their individual views about leadership rather than the leadership competency model they were asked to use. More specifically, analysis illuminated that minoritized search committee members had drastically different beliefs about leadership and experiences serving on the search committee. I concluded the study by outlining implications for policy, future practice, and future research, including offering a conceptual framework and tools for an equity-minded search process

    Radiation Protection for Lunar Mission Scenarios

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    Preliminary analyses of shielding requirements to protect astronauts from the harmful effects of radiation on both short-term and long-term lunar missions have been performed. Shielding needs for both solar particle events (SPEs) and galactic cosmic ray (GCR) exposure are discussed for transit vehicles and surface habitats. This work was performed under the aegis of two NASA initiatives. The first study was an architecture trade study led by Langley Research Center (LaRC) in which a broad range of vehicle types and mission scenarios were compared. The radiation analysis for this study primarily focused on the additional shielding mass required to protect astronauts from the rare occurrence of a large SPE. The second study, led by Johnson Space Center (JSC), involved the design of lunar habitats. Researchers at LaRC were asked to evaluate the changes to mission architecture that would be needed if the surface stay were lengthened from a shorter mission duration of 30 to 90 days to a longer stay of 500 days. Here, the primary radiation concern was GCR exposure. The methods used for these studies as well as the resulting shielding recommendations are discussed. Recommendations are also made for more detailed analyses to minimize shielding mass, once preliminary vehicle and habitat designs have been completed. Here, methodologies are mapped out and available radiation analysis tools are described. Since, as yet, no dosimetric limits have been adopted for missions beyond low earth orbit (LEO), radiation exposures are compared to LEO limits. Uncertainties associated with the LEO career effective dose limits and the effects of lowering these limits on shielding mass are also discussed

    Canadian national surveys on pandemic influenza preparations: pre-pandemic and peri-pandemic findings

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    BACKGROUND: Prior to the 2009 H1N1 Influenza pandemic, public health authorities in Canada and elsewhere prepared for the future outbreak, partly guided by an ethical framework developed within the Canadian Program of Research on Ethics in a Pandemic (CanPREP). We developed a telephone-based survey based on that framework, which was delivered across Canada in late 2008. In June, 2009, the WHO declared pandemic Phase 6 status and from the subsequent October (2009) until May 2010, the CanPREP team fielded a second (revised) survey, collecting another 1,000 opinions from Canadians during a period of pre-pandemic anticipation and peri-pandemic experience. METHODS: Surveys were administered by telephone with random sampling achieved via random digit dialing. Eligible participants were adults, 18 years or older, with per province stratification approximating provincial percentages of national population. Descriptive results were tabulated and logistic regression analyses used to assess whether demographic factors were significantly associated with outcomes, and to identify divergences (between the pre-pandemic and intra-pandemic surveys). RESULTS: N = 1,029 interviews were completed from 1,986 households, yielding a gross response rate of 52% (AAPOR Standard Definition 3). Over 90% of subjects indicated the most important goal of pandemic influenza preparations was saving lives, with 41% indicating that saving lives solely in Canada was the highest priority and 50% indicating saving lives globally was the highest priority. About 90% of respondents supported the obligation of health care workers to report to work and face influenza pandemic risks excepting those with serious health conditions which that increased risks. Strong majorities favoured stocking adequate protective antiviral dosages for all Canadians (92%) and, if effective, influenza vaccinations (95%). Over 70% agreed Canada should provide international assistance to poorer countries for pandemic preparation, even if resources for Canadians were reduced. CONCLUSIONS: Results suggest Canadians trust public health officials to make difficult decisions, providing emphasis is maintained on reciprocity and respect for individual rights. Canadians also support international obligations to help poorer countries and associated efforts to save lives outside the country, even if intra-national efforts are reduced

    beta-Hydroxy-beta-methylbutyrate free acid reduces markers of exercise-induced muscle damage and improves recovery in resistance-trained men

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    The purpose of the present study was to determine the effects of short-term supplementation with the free acid form of beta-hydroxy-beta-methylbutyrate (HMB-FA) on indices of muscle damage, protein breakdown, recovery and hormone status following a high-volume resistance training session in trained athletes. A total of twenty resistance-trained males were recruited to participate in a high-volume resistance training session centred on full squats, bench presses and dead lifts. Subjects were randomly assigned to receive either 3 g/d of HMB-FA or a placebo. Immediately before the exercise session and 48 h post-exercise, serum creatine kinase (CK), urinary 3-methylhistadine (3-MH), testosterone, cortisol and perceived recovery status (PRS) scale measurements were taken. The results showed that CK increased to a greater extent in the placebo (329%) than in the HMB-FA group (104%) (P=0.004, d=1.6). There was also a significant change for PRS, which decreased to a greater extent in the placebo (9.1 (SEM 0.4) to 4.6 (SEM 0.5)) than in the HMB-FA group (9.1 (SEM 0.3) to 6.3 (SEM 0.3)) (P=0.005, d = -0.48). Muscle protein breakdown, measured by 3-MH analysis, numerically decreased with HMB-FA supplementation and approached significance (P=0.08, d = 0.12). There were no acute changes in plasma total or free testosterone, cortisol or C-reactive protein. In conclusion, these results suggest that an HMB-FA supplement given to trained athletes before exercise can blunt increases in muscle damage and prevent declines in perceived readiness to train following a high-volume, muscle-damaging resistance-training session

    Na V 1.6a is required for normal activation of motor circuits normally excited by tactile stimulation

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    A screen for zebrafish motor mutants identified two noncomplementing alleles of a recessive mutation that were named non-active ( nav mi89 and nav mi130 ). nav embryos displayed diminished spontaneous and touch-evoked escape behaviors during the first 3 days of development. Genetic mapping identified the gene encoding Na V 1.6a ( scn8aa ) as a potential candidate for nav . Subsequent cloning of scn8aa from the two alleles of nav uncovered two missense mutations in Na V 1.6a that eliminated channel activity when assayed heterologously. Furthermore, the injection of RNA encoding wild-type scn8aa rescued the nav mutant phenotype indicating that scn8aa was the causative gene of nav . In-vivo electrophysiological analysis of the touch-evoked escape circuit indicated that voltage-dependent inward current was decreased in mechanosensory neurons in mutants, but they were able to fire action potentials. Furthermore, tactile stimulation of mutants activated some neurons downstream of mechanosensory neurons but failed to activate the swim locomotor circuit in accord with the behavioral response of initial escape contractions but no swimming. Thus, mutant mechanosensory neurons appeared to respond to tactile stimulation but failed to initiate swimming. Interestingly fictive swimming could be initiated pharmacologically suggesting that a swim circuit was present in mutants. These results suggested that Na V 1.6a was required for touch-induced activation of the swim locomotor network. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 70:508–522, 2010Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75774/1/20791_ftp.pd

    Nonuniversal Effects in the Homogeneous Bose Gas

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    Effective field theory predicts that the leading nonuniversal effects in the homogeneous Bose gas arise from the effective range for S-wave scattering and from an effective three-body contact interaction. We calculate the leading nonuniversal contributions to the energy density and condensate fraction and compare the predictions with results from diffusion Monte Carlo calculations by Giorgini, Boronat, and Casulleras. We give a crude determination of the strength of the three-body contact interaction for various model potentials. Accurate determinations could be obtained from diffusion Monte Carlo calculations of the energy density with higher statistics.Comment: 24 pages, RevTex, 5 ps figures, included with epsf.te

    Effect of Exercise Training and +Gz Acceleration Training on Men

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    Countermeasures for reduction in work capacity (maximal oxygen uptake and strength) during spaceflight and enhanced orthostatic intolerance during re-entry, landing and egress from the return vehicle are continuing problems. The purpose for this study was to test the hypothesis that passive-acceleration training; supine, interval, exercise plus acceleration training and exercise combined with acceleration training would improve orthostatic tolerance in ambulatory men; and that addition of the aerobic exercise conditioning would not alter this improved tolerance from that of passive-acceleration training. Seven men (24-38 yr) underwent "Passive" training on the Ames human-powered centrifuge (HPC) for 30 min, "Exercise" training on the cycle ergometer with constant +Gz acceleration; and "Combined" exercise training at 40% to 90% of the HPC +Gz(max) exercise level. Maximal supine exercise loads increased significant (P<0.05) by 8.3% (Passive), 12.6% (Exercise), and by 15.4% (Combined) after training, but their post-training maximal oxygen uptakes and maximal heart rates were unchanged. Maximal time to fatigue (endurance) was unchanged with Passive was increased (P<0.05) with Exercise and Combined training. Thus, the exercise in the Exercise and Combined training Phases resulted in greater maximal loads and endurance without effect on maximal oxygen uptake or heart rate. There was a 4% to 6% increase (P<0.05) in all four quadriceps muscle volumes (right and left) after post-Combined training. Resting pre-tilt heart rate was elevated by 12.9% (P<0.05) only after Passive training suggesting that the exercise training attenuated the HR response. Plasma volume (% Delta) was uniformly decreased by 8% to 14% (P<0.05) at tilt-tolerance pre- vs. post-training indicating essentially no effect of training on the level of hypovolemia. Post-training tilt-tolerance time and heart rate were increased (P<0.05) only with Passive training by 37.8% and by 29.1%, respectively. Thus, addition of exercise training appeared to attenuate the increased Passive tilt-tolerance
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