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    ABSTRACT: Landing an aircraft is a complex task that requires effective attentional control in order to be successful. The present study examined how anxiety may influence gaze behavior during the performance of simulated landings. Participants undertook simulated landings in low visibility conditions which required the use of cockpit instruments in order to obtain guidance information. Landings were performed in either anxiety or control conditions, with anxiety being manipulated using a combination of ego-threatening instructions and monetary incentives. Results showed an increase in percentage dwell time towards the outside world in the anxiety conditions. Visual scanning entropy, which is the predictability of visual scanning behavior, showed an increase in the randomness of scanning behavior when anxious. Furthermore, change in scanning randomness from the pre-test to anxiety conditions positively correlated with both the change in cognitive anxiety and change in performance error. These results support the viewpoint that anxiety can negatively affect attentional control.
    06/2014; 3:63-71. DOI:10.1016/j.jarmac.2014.04.010
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    ABSTRACT: Kidney transplantation is the preferred modality of renal replacement therapy. Long-term patient and graft survival have only improved marginally over the recent decade, mainly because of the development of cardiovascular disease after transplantation. Obesity is a risk factor for cardiovascular disease and is common before and after transplantation. This article reviews the literature assessing the role of pre- and post-transplant obesity on patient and graft survival, discusses the underlying obesity-related mechanisms leading to inferior kidney transplant outcomes, and explores the role of nutritional intervention on improving long-term outcomes of transplantation. Although the role of pretransplant obesity remains uncertain, post-transplant obesity increases the risk of graft failure and mortality. Nutritional intervention is effective in achieving post-transplant weight loss, but the effect on long-term outcomes has not been established. Future research should focus on conducting nutritional intervention studies aiming to improve long-term outcomes of kidney transplantation.
    Journal of Renal Nutrition 01/2014; 24(1):1-12. DOI:10.1053/j.jrn.2013.09.002
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    ABSTRACT: Acute bouts of high-intensity exercise modulate peripheral appetite regulating hormones to transiently suppress hunger. However, the effects of physical activity on central appetite regulation have yet to be fully investigated. We used functional magnetic resonance imaging (fMRI) to compare neural responses to visual food stimuli after intense exercise and rest. Fifteen lean healthy men (mean ± SD age: 22.5 ± 3.1 y; mean ± SD body mass index: 24.2 ± 2.4 kg/m(2)) completed two 60-min trials-exercise (EX; running at ∼70% maximum aerobic capacity) and a resting control trial (REST)-in a counterbalanced order. After each trial, an fMRI assessment was completed in which images of high- and low-calorie foods were viewed. EX significantly suppressed subjective appetite responses while increasing thirst and core-body temperature. Furthermore, EX significantly suppressed ghrelin concentrations and significantly enhanced peptide YY release. Neural responses to images of high-calorie foods significantly increased dorsolateral prefrontal cortex activation and suppressed orbitofrontal cortex (OFC) and hippocampus activation after EX compared with REST. After EX, low-calorie food images increased insula and putamen activation and reduced OFC activation compared with REST. Furthermore, left pallidum activity was significantly elevated after EX when low-calorie images were viewed and was suppressed when high-calorie images were viewed, and these responses correlated significantly with thirst. Exercise increases neural responses in reward-related regions of the brain in response to images of low-calorie foods and suppresses activation during the viewing of high-calorie foods. These central responses are associated with exercise-induced changes in peripheral signals related to appetite-regulation and hydration status. This trial was registered at www.clinicaltrials.gov as NCT01926431.
    American Journal of Clinical Nutrition 12/2013; 99(2). DOI:10.3945/ajcn.113.071381
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    ABSTRACT: Purpose: A driving simulator was used to examine the relationship between motion perception and driving performance. Although motion perception test scores have been shown to be related to driving safety, it is not clear which combination of tests are the best predictors and whether motion perception training can improve driving performance. Methods: In Experiment 1, 60 younger drivers (22.4 ± 2.5 years) completed three motion perception tests [2D motion-defined letter (MDL) identification, 3D motion in depth sensitivity (MID), and dynamic visual acuity (DVA)] followed by two driving tests [emergency braking (EB) and hazard perception (HP)]. In Experiment 2, 20 drivers (21.6 ± 2.1 years) completed 6 weeks of motion perception training (using the MDL, MID and DVA tests) while 20 control drivers (22.0 ± 2.7 years) completed an online driving safety course. EB performance was measured pre- and post-training. Results: In Experiment 1, both MDL (r = .34) and MID (r=.46) significantly correlated with EB score. The change in DVA score as a function of target speed (i.e., "velocity susceptibility") was most strongly correlated with HP score (r = -.61). In Experiment 2, the motion perception training group had a significant decrease in brake reaction time on the EB test from pre-post while there was no significant change for the control group: t(38) = 2.24, p = 0.03. Conclusions: Tests of 3D motion perception are the best predictor of EB while DVA velocity susceptibility is the best predictor of hazard perception. Motion perception training appears to result in faster braking responses.
    Investigative ophthalmology & visual science 11/2013; 54(13). DOI:10.1167/iovs.13-12774
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    ABSTRACT: The intake of whey, compared with casein and soy protein intakes, stimulates a greater acute response of muscle protein synthesis (MPS) to protein ingestion in rested and exercised muscle. We characterized the dose-response relation of postabsorptive rates of myofibrillar MPS to increasing amounts of whey protein at rest and after exercise in resistance-trained, young men. Volunteers (n = 48) consumed a standardized, high-protein (0.54 g/kg body mass) breakfast. Three hours later, a bout of unilateral exercise (8 × 10 leg presses and leg extensions; 80% one-repetition maximum) was performed. Volunteers ingested 0, 10, 20, or 40 g whey protein isolate immediately (∼10 min) after exercise. Postabsorptive rates of myofibrillar MPS and whole-body rates of phenylalanine oxidation and urea production were measured over a 4-h postdrink period by continuous tracer infusion of labeled [(13)C6] phenylalanine and [(15)N2] urea. Myofibrillar MPS (±SD) increased (P < 0.05) above 0 g whey protein (0.041 ± 0.015%/h) by 49% and 56% with the ingestion of 20 and 40 g whey protein, respectively, whereas no additional stimulation was observed with 10 g whey protein (P > 0.05). Rates of phenylalanine oxidation and urea production increased with the ingestion of 40 g whey protein. A 20-g dose of whey protein is sufficient for the maximal stimulation of postabsorptive rates of myofibrillar MPS in rested and exercised muscle of ∼80-kg resistance-trained, young men. A dose of whey protein >20 g stimulates amino acid oxidation and ureagenesis. This trial was registered at http://www.isrctn.org/ as ISRCTN92528122.
    American Journal of Clinical Nutrition 11/2013; 99(1). DOI:10.3945/ajcn.112.055517
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    ABSTRACT: Perception of hill slant is exaggerated in explicit awareness. Proffitt (Perspectives on Psychological Science 1:110-122, 2006) argued that explicit perception of the slant of a climb allows individuals to plan locomotion in keeping with their available locomotor resources, yet no behavioral evidence supports this contention. Pedestrians in a built environment can often avoid climbing stairs, the man-made equivalent of steep hills, by choosing an adjacent escalator. Stair climbing is avoided more by women, the old, and the overweight than by their comparators. Two studies tested perceived steepness of the stairs as a cue that promotes this avoidance. In the first study, participants estimated the steepness of a staircase in a train station (n = 269). Sex, age, height, and weight were recorded. Women, older individuals, and those who were heavier and shorter reported the staircase as steeper than did their comparison groups. In a follow-up study in a shopping mall, pedestrians were recruited from those who chose the stairs and those who avoided them, with the samples stratified for sex, age, and weight status. Participants (n = 229) estimated the steepness of a life-sized image of the stairs they had just encountered, presented on the wall of a vacant shop in the mall. Pedestrians who avoided stair climbing by choosing the escalator reported the stairs as steeper even when demographic differences were controlled. Perceived steepness may to be a contextual cue that pedestrians use to avoid stair climbing when an alternative is available.
    Psychonomic Bulletin & Review 11/2013; 21(3). DOI:10.3758/s13423-013-0535-8
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    ABSTRACT: The aim of this study was to investigate if duration of decaffeinated green tea extract (dGTE) ingestion plays a role in augmenting fat oxidation rates during moderate-intensity exercise. In a cross-over, placebo controlled design, 19 healthy males [x± SD age: 21 ± 2 y; weight 75.0 ± 7.0 kg; body mass index (BMI) 23.2 ± 2.2 kg[BULLET OPERATOR]m; maximal oxygen consumption (V˙O2max) 55.4 ± 4.6 mL[BULLET OPERATOR] kg[BULLET OPERATOR]min] ingested dGTE and placebo (PLA) for 28 days, separated by a 28 day wash-out period. On the first day (dGTE 1 or PLA 1) and following 7 days (dGTE 7 or PLA 7) and 28 days (dGTE 28 or PLA 28) participants completed a 30-min cycle exercise bout (50% Wmax), 2 hours after ingestion. Indirect calorimetry was used to calculate rates of whole body fat and carbohydrate oxidation during exercise. Blood samples were collected at rest and during exercise for analysis of plasma fatty acids (FA), glycerol and epigallocatechin gallate (EGCG). Ingestion of dGTE did not significantly change whole body fat oxidation rates during exercise on day 1, 7 or 28 compared to PLA. There were also no changes in plasma concentrations of FA and glycerol at rest and during exercise as a result of dGTE ingestion at any time point compared to PLA. Plasma EGCG concentrations, immediately prior to the exercise bout, in the three dGTE trials were elevated compared with PLA but not different between 1, 7 and 28 days. In contrast to previous reports we found that duration of dGTE ingestion had no effect on whole body fat oxidation rates or fat metabolism-related blood metabolites during exercise in physically active healthy males.
    Medicine and science in sports and exercise 10/2013; DOI:10.1249/MSS.0000000000000205
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    ABSTRACT: The concept of bracketed morality has received empirical support in several sport studies (e.g., Bredemeier & Shields, 1986a, 1986b). However, these studies have focused on moral reasoning. In this research, we examined bracketed morality with respect to moral behavior in sport and university contexts, in two studies. Male and female participants (Study 1: N = 331; Study 2: N = 372) completed questionnaires assessing prosocial and antisocial behavior toward teammates and opponents in sport and toward other students at university. Study 2 participants also completed measures of moral disengagement and goal orientation in both contexts. In most cases, behavior in sport was highly correlated with behavior at university. In addition, participants reported higher prosocial behavior toward teammates and higher antisocial behavior toward opponents in sport than toward other students at university. The effects of context on antisocial behavior were partially mediated by moral disengagement and ego orientation. Our findings extend the bracketed morality concept to prosocial and antisocial behavior.
    Journal of Sport and Exercise Psychology 10/2013; 35(5):449-63.
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    ABSTRACT: The present study examined the relationship between habitual physical activity, life events stress, the diurnal rhythms of cortisol and DHEA, and the cortisol: dehydroepiandrosterone (DHEA) ratio in older adults. Thirty six participants aged ≥ 65 reported their habitual physical activity, and indicated if a particular event happened to them in the past year (stress incidence) and how stressful they perceived the event to be (stress severity). Older adults with higher stress severity demonstrated a significantly higher cortisol:DHEA ratio. Individuals with higher stress incidence scores, who did not participate in aerobic exercise had a significantly higher cortisol:DHEA ratio and flatter DHEA diurnal rhythm compared with those who regularly participated in aerobic exercise. In conclusion, life events stress may have a negative impact on the cortisol:DHEA ratio in older adults. Under conditions of high stress exposure, exercise may protect older adults from an increased cortisol:DHEA ratio and flatter DHEA diurnal rhythm.
    Journal of Aging and Physical Activity 10/2013; 22(4). DOI:10.1123/JAPA.2012-0082
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    ABSTRACT: New findings What is the topic of this review? This brief review describes the work of Professor John Coote and colleagues at the University of Birmingham, which has contributed to understanding of the role of muscle afferent involvement in cardiorespiratory control in exercise. What advances does it highlight? The seminal findings of John Coote's early work are highlighted, as well as more recent developments in the field, especially the role of muscle afferents in the control of human ventilation during exercise. Through the work of John Coote, research into the role of muscle afferent involvement in cardiorespiratory control has had strong links with Birmingham since the late 1960s. This brief review gives an historical background to John's early work and how his research and mentorship of colleagues continues to have a profound influence on the field today.
    Experimental physiology 09/2013; 99(2). DOI:10.1113/expphysiol.2013.072645
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