Oculomotor responses and 3D displays

This thesis investigated some of the eye movement factors related to the development and use of eye pointing devices with three dimensional displays (stereoscopic and linear perspective). In order for eye pointing to be used as a successful device for input-control of a 3D display it is necessary to characterise the accuracy and speed with which the binocular point of foveation can locate a particular point in 3D space. Linear perspective was found to be insufficient to elicit a change in the depth of the binocular point of fixation except under optimal conditions (monocular viewing, accommodative loop open and constant display paradigm). Comparison of the oculomotor responses made between a stereoscopic 'virtual' and a 'real' display showed there were no differences with regards to target fixational accuracy. With one exception, subjects showed the same degree of fixational accuracy with respect to target direction and depth. However, close target proximity (in terms of direction) affected the accuracy of fixation with respect to depth (but not direction). No differences were found between fixational accuracy of large and small targets under either display conditions. The visual conditions eliciting fast changes in the location of the binocular point of foveation, i.e. saccade disconjugacy, were investigated. Target-directed saccade disconjugacy was confirmed, in some cases, between targets presented at different depths on a stereoscopic display. However, in general the direction of saccade disconjugacy was best predicted by the horizontal direction of the target. Leftward saccade disconjugacy was more divergent than rightward. This asymmetry was overlaid on a disconjugacy response, which when considered in relative terms, was appropriated for the level of vergence demand. Linear perspective depth cues did not elicit target-directed disconjugate saccades

An Evaluation of Mississippi Barrier Islands as a Spawning and Nesting Habitat for the American Horseshoe Crab, Limulus polyphemus, with Implications for Island Restoration

The American horseshoe crab (HSC), Limulus polyphemus, is an economically and ecologically important species in the coastal ecosystem. Horseshoe crabs inhabit the continental shelf and estuaries from Maine to the central Gulf Coast and the Yucatán Peninsula. Although the presence of horseshoe crabs in southern Mississippi is known locally, there are limited data specific to the area and population, particularly regarding spawning and nesting habitat. Surveys of HSC presence, habitat use, and behavior on Mississippi barrier islands were conducted between March and November 2007 to 2009. These data, combined with habitat surveys of the barrier islands, were used to characterize HSC use of these islands. Horseshoe crabs were present on barrier island beaches from March to November, but active spawning and nesting occurred primarily in April and May. Peak abundance varied by year but not between islands surveyed. Nesting activity was only observed on the north side of both islands and was generally clustered in areas with a mild elevation profile. In comparison to other studied populations both in the Gulf of Mexico (GOM) and along the U.S. Atlantic coast, HSC nesting on Mississippi barrier islands followed generally similar patterns, but did display some important differences. Nesting was highest in low energy, well oxygenated habitat, which included the sub-tidal sand flats that are common along these islands. In addition, HSC are smaller than the range-wide mean reported in the literature, but that may be related to these islands being close to the edge of the reported HSC range in the GOM. The continued existence of HSC in Mississippi appears tied to their preference for barrier island beaches as spawning and nursery habitat. More research is needed, but this study documents that the distribution of HSC nesting habitat includes Mississippi beaches and this should be considered as a part of restoration plans being evaluated for these barrier islands

The Impact of Human Resource Management on Organizational Success: Suggestions for Hospitality Educators

A recent article in the Hospitality and Tourism Educator (Van Hoof, 1991) reported that recruiters for lodging and foodservice organizations consider human resource management (HRM) to be of primary importance when educating hospitality graduate students. The criticality and impact of HRM in the lodging and foodservice industries has been confirmed time and again by recruiters and leaders in the field. And yet, while HRM professionals and corporate leaders publicly acknowledge the importance of HRM, how do operational managers and employees view HRM\u27s role in addressing critical success factors such as increased profitability and enhanced service delivery? Is HRM narrowly confined to the traditional activities of hiring and firing, or is it perceived as having an impact on important strategic issues? This article reports on a study that examined whether HRM is viewed as having an impact on success factors outside of those traditionally associated with it. Data garnered from a restaurant chain is summarized; however the primary purpose is not to discuss the details of the research, but to consider the implications of the study’s findings for hospitality educators. Thus, the primary objective of this paper is to offer suggestions to educators about how to expose future managers to the potential roles HRM can play in operational issues. Before examining what educators can do to enhance student awareness of how to utilize the principles of HRM, we report on what practicing managers believe is the impact of HRM on critical success factors. Curiously, few researchers have explored systematically the question of whether HRM is perceived to have an impact on critical success factors outside the traditional personnel management domains of selection, retention, and payroll administration

Human Resources as a Strategic Partner in Multiunit-Restaurants

Despite the importance of human-resources issues to the success of chain-restaurant business, a close look at one such company indicates that human resources managers are not yet party to firms’ strategic decision making

Music listening and hearing aids: perspectives from audiologists and their patients

Objective: Two studies explored hearing-aid user and audiologist experiences of hearing-aid use and fitting for music in the UK. Design and sample: One-hundred-seventy-six hearing-aid users (age range: 21–93 years; mean: 60.56 years) answered a 4-item questionnaire on music listening difficulties and discussions about music in clinic. 99 audiologists (age range: 22–71 years; mean: 39.18 years) answered a 36-item questionnaire on the frequency and type of discussions, training received, and strategies for optimizing hearing aids for music. Closed and open-ended questions were included. Results: Sixty seven percent of hearing-aid users reported some degree of difficulty listening to music with hearing aids, and 58% had never discussed music in clinic. 50% of audiologists surveyed asked 1 in 5 (or fewer) patients about music and 67% had never received music-specific training. Audiologist training on music was significantly associated with confidence in providing advice, confidence in programming hearing aids for music, and programming hearing aids for music for a greater number of patients. Conclusions: Hearing-aid users’ and audiologists’ experiences of music remain mixed. In the absence of formalised training in optimizing hearing aids for music, there is a need for systematic research relating fitting strategies to clinical outcomes and the development of guidelines for audiologist training

Contralateral fatigue during severe-intensity single-leg exercise: influence of acute acetaminophen ingestion

Exhaustive single-leg exercise has been suggested to reduce time to task failure (Tlim) during subsequent exercise in the contralateral leg by exacerbating central fatigue development. We investigated the influence of acetaminophen (ACT), an analgesic that may blunt central fatigue development, on Tlim during single-leg exercise completed with and without prior fatiguing exercise of the contralateral leg. Fourteen recreationally active men performed single-leg severe-intensity knee-extensor exercise to Tlim on the left (Leg1) and right (Leg2) legs without prior contralateral fatigue and on Leg2 immediately following Leg1 (Leg2-CONTRA). The tests were completed following ingestion of 1-g ACT or maltodextrin [placebo (PL)] capsules. Intramuscular phosphorus-containing metabolites and substrates and muscle activation were assessed using 31P-MRS and electromyography, respectively. Tlim was not different between Leg1ACT and Leg1PL conditions (402 ± 101 vs. 390 ± 106 s, P = 0.11). There was also no difference in Tlim between Leg2ACT-CONTRA and Leg2PL-CONTRA (324 ± 85 vs. 311 ± 92 s, P = 0.10), but Tlim was shorter in Leg2ACT-CONTRA and Leg2PL-CONTRA than in Leg2CON (385 ± 104 s, both P 0.05). These findings suggest that levels of metabolic perturbation and muscle activation at Tlim are not different during single-leg severe-intensity knee-extensor exercise completed with or without prior fatiguing exercise of the contralateral leg. Despite contralateral fatigue, ACT ingestion did not alter neuromuscular responses, muscle metabolites, or exercise performance.This article is freely available via Open Access. Click on the Publisher URL to access it via the publisher's site.This research was not sponsored by any funding body external to the University of Exeter. J. Fulford’s salary was supported via National Institute for Health Research Grant CRF/2016/10027 to the University of Exeter.Accepted version (12 month embargo

The reliability of 31P-MRS and NIRS measurements of spinal muscle function

This is the accepted, peer reviewed version of the article, which has been published in final form at doi: 10.1055/s-0034-1372639Phosphorous magnetic resonance spectroscopy (31P-MRS) and near-infra red spectroscopy (NIRS) provide methods for measuring spinal muscle function non-invasively but their reliability is not established. The aim of this study was assess the reliability (ICC) and error magnitude (CV%) of measurements of muscle phosphocreatine (PCr), tissue oxygenation index (TOI), and muscle deoxyhaemoglobin (HHb) acquired during fatigue and in recovery after 24 s exercise in the lumbar muscles. Ten healthy participants (19-25 years, 5 male, 5 female) performed exercise that involved holding the upper body unsupported in slight extension until fatigue and then, after 30 minutes of rest, for repeated bursts of 24 seconds. ICCs indicated good to excellent reliability of baseline measures (TOI:0.75) and of amplitude changes during fatigue (PCr:0.73, TOI:0.69, HHb:0.80), and recovery (HHb:0.96) and poor to fair reliability for time constants describing rates of change during fatigue (PCr:0.11) and recovery (PCr:0.31, HHb:0.47). CV% indicated varying relative measurement error across baseline measures (TOI:5%), amplitude changes during fatigue (PCr:7%, TOI:38%, HHb:31%) and recovery (HHb:31%), and in time constants for fatigue (PCr:39%) and recovery (PCr:20%, HHb:37%). The results suggested that reliability would be sufficient for future studies on spinal muscle function but that measurement error may be too large to evaluate individuals.NIHREPSR

Dietary nitrate accelerates postexercise muscle metabolic recovery and O2 delivery in hypoxia.

We tested the hypothesis that the time constants (τ) of postexercise T2* MRI signal intensity (an index of O2 delivery) and muscle [PCr] (an index of metabolic perturbation, measured by (31)P-MRS) in hypoxia would be accelerated after dietary nitrate (NO3 (-)) supplementation. In a double-blind crossover design, eight moderately trained subjects underwent 5 days of NO3 (-) (beetroot juice, BR; 8.2 mmol/day NO3 (-)) and placebo (PL; 0.003 mmol/day NO3 (-)) supplementation in four conditions: normoxic PL (N-PL), hypoxic PL (H-PL; 13% O2), normoxic NO3 (-) (N-BR), and hypoxic NO3 (-) (H-BR). The single-leg knee-extension protocol consisted of 10 min of steady-state exercise and 24 s of high-intensity exercise. The [PCr] recovery τ was greater in H-PL (30 ± 4 s) than H-BR (22 ± 4 s), N-PL (24 ± 4 s) and N-BR (22 ± 4 s) (P 0.05). These findings suggest that the NO3 (-)-NO2 (-)-NO pathway is a significant modulator of muscle energetics and O2 delivery during hypoxic exercise and subsequent recovery.J. Fulford's salary was supported via National Institute of Health Research Grant 50112

Influence of hyperoxia on muscle metabolic responses and the power-duration relationship during severe-intensity exercise in humans: a 31P magnetic resonance spectroscopy study

addresses: School of Sport and Health Sciences, St Luke's Campus, University of Exeter, Exeter EX1 2LU, UK.types: Journal Article; Randomized Controlled TrialThis is the author's post-print version of an article published in Experimental Physiology, 2010, Vol. 95, Issue 4, pp. 528 – 540 Copyright © 2010 Wiley-Blackwell /The Physiological Society. The definitive version is available at www3.interscience.wiley.comSevere-intensity constant-work-rate exercise results in the attainment of maximal oxygen uptake, but the muscle metabolic milieu at the limit of tolerance (T(lim)) for such exercise remains to be elucidated. We hypothesized that T(lim) during severe-intensity exercise would be associated with the attainment of consistently low values of intramuscular phosphocreatine ([PCr]) and pH, as determined using (31)P magnetic resonance spectroscopy, irrespective of the work rate and the inspired O(2) fraction. We also hypothesized that hyperoxia would increase the asymptote of the hyperbolic power-duration relationship (the critical power, CP) without altering the curvature constant (W). Seven subjects (mean +/- s.d., age 30 +/- 9 years) completed four constant-work-rate knee-extension exercise bouts to the limit of tolerance (range, 3-10 min) both in normoxia (N) and in hyperoxia (H; 70% O(2)) inside the bore of 1.5 T superconducting magnet. The [PCr] (approximately 5-10% of resting baseline) and pH (approximately 6.65) at the limit of tolerance during each of the four trials was not significantly different either in normoxia or in hyperoxia. At the same fixed work rate, the overall rate at which [PCr] fell with time was attenuated in hyperoxia (mean response time: N, 59 +/- 20 versus H, 116 +/- 46 s; P < 0.05). The CP was higher (N, 16.1 +/- 2.6 versus H, 18.0 +/- 2.3 W; P < 0.05) and the W was lower (N, 1.92 +/- 0.70 versus H, 1.48 +/- 0.31 kJ; P < 0.05) in hyperoxia compared with normoxia. These data indicate that T(lim) during severe-intensity exercise is associated with the attainment of consistently low values of muscle [PCr] and pH. The CP and W parameters of the power-duration relationship were both sensitive to the inspiration of hyperoxic gas