Enhancing Teacher Credibility: What We Can Learn From the Justice and Leadership Literature

Enhanced perceptions of instructor credibility are related to positive outcomes in the classroom, including participation and learning (Chory, 2007; Frymier & Thompson, 1992; McCroskey & Teven, 1999; Myers, 2004; Teven & McCroskey, 1997). We contend that student perceptions of instructor credibility can be directly impacted by applying management research to classroom practices. In other words, actionable management research is useful in the classroom not just to share with students because it may make them better managers, but also to improve teaching practices and related outcomes. The present article explores this tenet, first discussing why we believe applied research findings can and should be transferred to the classroom and then using Implicit Leadership Theory (ILT) and organizational justice literature to demonstrate how these concepts can be generalized to the classroom environment to ultimately enhance instructor credibility

Bioimpedance-derived membrane capacitance: Clinically relevant sources of variability, precision, and reliability

Membrane capacitance (

Self-Reported Low Vitality, Poor Mental Health, and Low Dietary Restraint Are Associated with Overperception of Physical Exertion

Objective. We investigated whether perceived exertion, in comparison to the physiological response to exercise, was associated with self-reported vitality, mental health, and physical function during daily activities, or weight control behaviors. Design. Weight-reduced, formerly overweight women (n = 126, aged 22–46 years), completed health and dietary control questionnaires, and underwent a treadmill-walking task while heart rate, ventilation, respiratory exchange ratio, and ratings of perceived exertion were recorded. Results. Overperception of exertion (perceived exertion physiological exertion) was inversely associated with vitality (r = −0.190, P < .05), mental health (r = −0.188, P < .05), and dietary control (r values range −0.231 to −0.317, P < .05). In linear regression modeling, vitality or mental health, and cognitive dietary restraint were independently associated with accuracy of perceived exertion, independent of age, ethnicity, and engagement in exercise during weight loss. Each model explained 7%-8% of the variance in accuracy of perceived exertion. Conclusion. Women with low vitality or poor mental health, and poor dietary control may overperceive exertion. Such overperception may be a barrier to engage in physical activity and thus increase susceptibility to weight gain

Associations of Mitochondrial Fatty Acid Oxidation with Body Fat in Premenopausal Women

Higher in vivo fatty acid (FA) oxidation rates have been reported in obese individuals compared to lean counterparts; however whether this reflects a shift in substrate-specific oxidative capacity at the level of the skeletal muscle mitochondria has not been examined. The purpose of this study was to test the hypothesis that in situ measures of skeletal muscle mitochondria FA oxidation would be positively associated with total body fat. Participants were 38 premenopausal women (BMI=26.5±4.3 kg/m2). Total and regional fat were assessed by dual-energy X-ray absorptiometry (DXA). Mitochondrial FA oxidation was assessed in permeabilized myofibers using high-resolution respirometry and a palmitoyl carnitine substrate. We found positive associations of total fat mass with State 3 (ADP-stimulated respiration) (r=0.379, p<0.05) and the respiratory control ratio (RCR, measure of mitochondrial coupling) (r=0.348, p<0.05). When participants were dichotomized by high or low body fat percent, participants with high total body fat displayed a higher RCR compared to those with low body fat (p<0.05). There were no associations between any measure of regional fat and mitochondrial FA oxidation independent of total fat mass. In conclusion, greater FA oxidation in obesity may reflect molecular processes that enhance FA oxidation capacity at the mitochondrial level

Vitamin D intake is associated with insulin sensitivity in African American, but not European American, women

<p>Abstract</p> <p>Background</p> <p>The prevalence of type 2 diabetes is higher among African Americans (AA) vs European Americans (EA), independent of obesity and other known confounders. Although the reason for this disparity is not known, it is possible that relatively low levels of vitamin D among AA may contribute, as vitamin D has been positively associated with insulin sensitivity in some studies. The objective of this study was to test the hypothesis that dietary vitamin D would be associated with a robust measure of insulin sensitivity in AA and EA women.</p> <p>Methods</p> <p>Subjects were 115 African American (AA) and 137 European American (EA) healthy, premenopausal women. Dietary intake was determined with 4-day food records; the insulin sensitivity index (S_I) with a frequently-sampled intravenous glucose tolerance test and minimal modeling; the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) with fasting insulin and glucose; and body composition with dual-energy X-ray absorptiometry.</p> <p>Results</p> <p>Vitamin D intake was positively associated with S_I(standardized β = 0.18, <it>P </it>= 0.05) and inversely associated with HOMA-IR (standardized β = -0.26, <it>P </it>= 0.007) in AA, and the relationships were independent of age, total body fat, energy intake, and % kcal from fat. Vitamin D intake was not significantly associated with indices of insulin sensitivity/resistance in EA (standardized β = 0.03, <it>P </it>= 0.74 and standardized β = 0.02, <it>P </it>= 0.85 for S_Iand HOMA-IR, respectively). Similar to vitamin D, dietary calcium was associated with S_Iand HOMA-IR among AA but not EA.</p> <p>Conclusions</p> <p>This study provides novel findings that dietary vitamin D and calcium were independently associated with insulin sensitivity in AA, but not EA. Promotion of these nutrients in the diet may reduce health disparities in type 2 diabetes risk among AA, although longitudinal and intervention studies are required.</p

Defining healthrelated obesity in prepubertal children

Abstract HIGGINS, PAUL B., BARBARA A. GOWER, GARY R. HUNTER, AND MICHAEL I. GORAN. Defining health-related obesity in prepubertal children. Obes Res. 2001;9:233-240. Objective: The purpose of this study was to develop percentage of fat and waist circumference cut-points in prepubertal children with the intention of defining obesity associated with cardiovascular disease (CVD) risk. Research Methods and Procedures: A cross-sectional analysis of 87 prepubertal children aged 4 to 11 years was used. Percentage of body fat was determined by DXA. Waist circumference was measured to the nearest millimeter. Receiver Operating Characteristic analyses of percentage of fat and waist circumference were used to develop cut-points for individuals with adverse levels of CVD risk factors. Results: The risk factors selected for analyses (i.e., fasting insulin, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, and total cholesterol/ high-density lipoprotein cholesterol) were significantly related to percentage of body fat and waist circumference. Likelihood ratios were used to identify percentage of fat and waist circumference cut-points associated with adverse cardiovascular risk profiles. Two cut-points, an upper cut-point of 33% body fat and a lower cut-point of 20% body fat, were derived. Waist circumference cut-points indicative of adverse and normal risk-factor profiles were 71 cm and 61 cm, respectively. Discussion: The data indicate that children with Ն33% body fat and children with a waist circumference Ն71 cm were more likely to possess an adverse CVD risk-factor profile than a normal risk-factor profile. The likelihood of children with Ͻ20% body fat or a waist circumference Ͻ61 cm possessing an adverse CVD risk-factor profile as opposed to a normal risk-factor profile was small. The cutpoints describe an adequate health-related definition of childhood obesity

African Ancestry Gradient Is Associated with Lower Systemic F 2

Context. Low levels of systemic F2-isoprostanes (F2-IsoP) increase the risk of diabetes and weight gain and were found in African Americans. Low F2-IsoPs could reflect an unfavorable metabolic characteristic, namely, slow mitochondrial metabolism in individuals with African ancestry. Objective. To examine differences in plasma F2-IsoPs in three groups with a priori different proportion of African ancestry: non-Hispanic Whites (NHWs), US-born African Americans (AAs), and West African immigrants (WAI). Design. Cross-sectional study. Setting. Georgia residents recruited from church communities. Participants. 218 males and females 25–74 years of age, who are self-identified as NHW (n=83), AA (n=56), or WAI (n=79). Main Outcome Measure(s). Plasma F2-IsoPs quantified by gas chromatography-mass spectrometry. Results. After adjustment for age, gender, obesity, and other comorbidities, WAI had lower levels of plasma F2-IsoP than AA (beta-coefficient = −9.8, p<0.001) and AA had lower levels than NHW (beta-coefficient = −30.3, p<0.001). Similarly, among healthy nonobese participants, F2-IsoP levels were lowest among WAI, followed by AA, and the highest levels were among NHW. Conclusion. Plasma F2-IsoPs are inversely associated with African ancestry gradient. Additional studies are required to test whether optimization of systemic F2-IsoP levels can serve as means to improve race-specific lifestyle and pharmacological intervention targeted to obesity prevention and treatment

Concentration-Dependent Effects of a Dietary Ketone Ester on Components of Energy Balance in Mice

Objectives: Exogenous ketones may provide therapeutic benefit in treatment of obesity. Administration of the ketone ester (KE) R,S-1,3-butanediol acetoacetate diester (BD-AcAc2) decreases body weight in mice, but effects on energy balance have not been extensively characterized. The purpose of this investigation was to explore concentration-dependent effects of BD-AcAc2 on energy intake and expenditure in mice.Methods: Forty-two male C57BL/6J mice were randomly assigned to one of seven isocaloric diets (n = 6 per group): (1) Control (CON, 0% KE by kcals); (2) KE5 (5% KE); (3) KE10 (10% KE); (4) KE15 (15% KE); (5) KE20 (20% KE); (6) KE25 (25% KE); and (7) KE30 (30% KE) for 3 weeks. Energy intake and body weight were measured daily. Fat mass (FM), lean body mass (LBM), and energy expenditure (EE) were measured at completion of the study. Differences among groups were compared to CON using ANOVA and ANCOVA.Results: Mean energy intake was similar between CON and each concentration of KE, except KE30 which was 12% lower than CON (P &lt; 0.01). KE25 and KE30 had lower body weight and FM compared to CON, while only KE30 had lower LBM (P &lt; 0.03). Adjusted resting and total EE were lower in KE30 compared to CON (P &lt; 0.03), but similar for all other groups.Conclusions: A diet comprised of 30% energy from BD-AcAc2 results in lower energy intake, coincident with lower body weight and whole animal adiposity; while KE20 and KE25 have significantly lower body weight and adiposity effects independent of changes in energy intake or expenditure