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951.
Frances O’Brien 《Higher Education》2009,58(1):29-39
Engagement between higher education and other societal sectors is a key theme in higher education discourse in South Africa,
as it is in other countries. In South Africa, however, engagement has gained additional status as an appropriate strategy
for pursuing African Scholarship. On the ground, however, inequitable power relationships and erratic participation have posed
serious challenges to the effectiveness and sustainability of engagement initiatives. From the experiences of seven South
African academics and the local community members and service-providers with whom they engaged in service-learning, three
factors emerged as mediating the power/participation dynamic of their engagement. The impact of these factors, namely, structure,
meaning, and place and time, are discussed, leading to the conclusions that scholarly engagement requires ideological and
practical support from higher education institutions and further study in South African contexts.
相似文献
Frances O’BrienEmail: |
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953.
W. Laiwattanapaisal J. Yakovleva M. Bengtsson T. Laurell S. Wiyakrutta V. Meevootisom O. Chailapakul J. Emn��us 《Biomicrofluidics》2009,3(1)
Two microfluidic systems have been developed for specific analysis of L-glutamate in food based on substrate recycling fluorescence detection. L-glutamate dehydrogenase and a novel enzyme, D-phenylglycine aminotransferase, were covalently immobilized on (i) the surface of silicon microchips containing 32 porous flow channels of 235 μm depth and 25 μm width and (ii) polystyrene Poros™ beads with a particle size of 20 μm. The immobilized enzymes recycle L-glutamate by oxidation to 2-oxoglutarate followed by the transfer of an amino group from D-4-hydroxyphenylglycine to 2-oxoglutarate. The reaction was accompanied by reduction of nicotinamide adenine dinucleotide (NAD+) to NADH, which was monitored by fluorescence detection (εex=340 nm, εem=460 nm). First, the microchip-based system, L-glutamate was detected within a range of 3.1–50.0 mM. Second, to be automatically determined, sequential injection analysis (SIA) with the bead-based system was investigated. The bead-based system was evaluated by both flow injection analysis and SIA modes, where good reproducibility for L-glutamate calibrations was obtained (relative standard deviation of 3.3% and 6.6%, respectively). In the case of SIA, the beads were introduced and removed from the microchip automatically. The immobilized beads could be stored in a 20% glycerol and 0.5 mM ethylenediaminetetraacetic acid solution maintained at a pH of 7.0 using a phosphate buffer for at least 15 days with 72% of the activity remaining. The bead-based system demonstrated high selectivity, where L-glutamate recoveries were between 91% and 108% in the presence of six other L-amino acids tested. 相似文献
954.
Gea O. F. Parikesit Jeffrey S. Guasto Salvatore Girardo Elisa Mele Ripalta Stabile Dario Pisignano Ralph Lindken Jerry Westerweel 《Biomicrofluidics》2009,3(4)
Nanoparticle image velocimetry (nano-PIV), based on total internal reflection fluorescent microscopy, is very useful to investigate fluid flows within ∼100 nm from a surface; but so far it has only been applied to flow over smooth surfaces. Here we show that it can also be applied to flow over a topologically structured surface, provided that the surface structures can be carefully configured not to disrupt the evanescent-wave illumination. We apply nano-PIV to quantify the flow velocity distribution over a polydimethylsiloxane surface, with a periodic gratinglike structure (with 215 nm height and 2 μm period) fabricated using our customized multilevel lithography method. The measured tracer displacement data are in good agreement with the computed theoretical values. These results demonstrate new possibilities to study the interactions between fluid flow and topologically structured surfaces. 相似文献
955.
R. Sakthivel R. Sakthivel V. Nithya P. Selvaraj O.M. Kwon 《Journal of The Franklin Institute》2018,355(14):6353-6370
This paper studies the robust stochastic stabilization problem for a class of fuzzy Markovian jump systems with time-varying delay and external disturbances via sliding mode control scheme. Based on the equivalent-input-disturbance (EID) approach, an online disturbance estimator is implemented to reject the unknown disturbance effect on the considered system. Specifically, to obtain exact EID estimation Luenberger fuzzy state observer and a low-pass filter incorporated to the closed-loop system. Moreover, novel fuzzy EID-based sliding mode control law is constructed to ensure the stability of the closed-loop system with satisfactory disturbance rejection performance. By employing Lyapunov stability theory and some integral inequalities, a new set of delay-dependent robust stability conditions is derived in terms of linear matrix inequalities (LMIs). The resulting LMI is used to find the gains of the state-feedback controller and the state observer a for the resulting closed-loop system. At last, numerical simulations based on the single-link arm robot model are provided to illustrate the proposed design technique. 相似文献
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Shannon O’Donnell Steve Bird Gregory Jacobson Matthew Driller 《European Journal of Sport Science》2018,18(5):611-618
Stress hormone and sleep differences in a competition versus training setting are yet to be evaluated in elite female team-sport athletes. The aim of the current study was to evaluate salivary cortisol and perceptual stress markers during competition and training and to determine the subsequent effects on sleep indices in elite female athletes. Ten elite female netball athletes (mean?±?SD; age: 23?±?6 years) had their sleep monitored on three occasions; following one netball competition match (MATCH), one netball match simulation session (TRAIN), and one rest day (CONTROL). Perceived stress values and salivary cortisol were collected immediately pre- (17:15 pm) and post-session (19:30 pm), and at 22:00 pm. Sleep monitoring was performed using wrist actigraphy assessing total time in bed, total sleep time (TST), efficiency (SE%), latency, sleep onset time and wake time. Cortisol levels were significantly higher (p?.01) immediately post MATCH compared with TRAIN and CONTROL (mean?±?SD; 0.700?±?0.165, 0.178?±?0.127 and 0.157?±?0.178?μg/dL, respectively) and at 22:00 pm (0.155?±?0.062, 0.077?±?0.063, and 0.089?±?0.083?μg/dL, respectively). There was a significant reduction in TST (?118?±?112?min, p?.01) and SE (?7.7?±?8.5%, p?.05) following MATCH vs. TRAIN. Salivary cortisol levels were significantly higher, and sleep quantity and quality were significantly reduced, following competition when compared to training and rest days. 相似文献
958.
Lachlan Mitchell Gary Slater Daniel Hackett Nathan Johnson Helen O’connor 《European Journal of Sport Science》2018,18(5):619-629
This study aimed to describe the body composition and physiological changes which take place during the in-season and recovery periods of a group of natural bodybuilders. Natural male bodybuilders (n?=?9) were assessed 16 (PRE16), 8 (PRE8), and 1 (PRE1) week(s) before, and 4 (POST4) weeks after a bodybuilding competition. Assessments included body composition, resting metabolic rate (RMR), serum hormones, and 7-day weighed food and training diaries. Change in parameters was assessed using repeated-measures analysis of variance. Dietary protein intake remained high throughout the study period (2.8–3.1?g?kg?1?d?1). Fat mass (FM) was significantly reduced from PRE16 to PRE1 (8.8?±?3.1 vs. 5.3?±?2.4?kg, P?.01). There was a small decrease in lean mass (LM) from PRE8 to PRE1 (71.8?±?9.1 vs. 70.9?±?9.1?kg, P?.05). No changes in RMR were observed (P?>?.05). Large reductions in total and free testosterone (16.4?±?4.4 vs. 10.1?±?3.6?nmol?L?1, P?.05; 229.3?±?72.4 vs. 116.8?±?76.9?pmol?L?1, P?.05), and insulin-like growth factor-1 (IGF-1) (27.0?±?7.7 vs. 19.9?±?7.6?nmol?L?1, P?.05) occurred between PRE16 and PRE1. LM and IGF-1 increased from PRE1 to POST4 (70.9?±?9.1 vs. 72.5?±?8.5?kg, P?.05; 19.9?±?7.6 vs. 25.4?±?9.3?nmol?L?1, P?.05). Despite substantial reductions in FM, participants maintained almost all of their LM. The reduction in anabolic hormone concentration is likely attributable to the prolonged negative energy balance, despite a high dietary protein intake. 相似文献
959.
The reported incidence of head and neck injuries in hurling is 0.12 per 1000 hours, but no previous research has quantified head impact characteristics in this sport. Here, a wireless accelerometer and gyroscope captured head impacts, in 20 senior club level hurling players. Peak linear and rotational acceleration and impact location were recorded during three hurling training sessions, each player participating once. A mean of 27.9 impacts (linear acceleration >10g) per player, per session were recorded; 1314 impacts during a total exposure time of 247 minutes. Only 2.6% impacts had peak linear acceleration of >70g and 6.2% had peak rotational acceleration >7900 rad/s2. There were significant differences in the number and magnitude of impacts, quantified by the accelerometer, between three training sessions of differing intensity (?2 0.03–0.09, p < 0.001). This study represents a first step in quantifying head impacts during hurling, demonstrating the feasibility of this technology in the field. The sensors were able to discriminate between sessions of varying intensity. These data can be used to develop athlete monitoring protocols and may be useful in developing innovative helmet-testing standards for hurling. The potential for this technology to provide feedback has clinical utility for team medical personnel. 相似文献
960.