2,034 research outputs found

    The differential interaction effect of mastery and performance climate on athletes’ emotional and physical exhaustion:The role of athletes’ gratitude.

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    Motivational climate (i.e., mastery and performance climate) has been found to shape athletes’ emotional and physical exhaustion, the core dimension of burnout. However, the interactional effect between mastery and performance climate on emotional and physical exhaustion has been rarely examined. In this study, we proposed that athletes’ gratitude will determine the interaction effect of mastery climate and performance climate on emotional and physical exhaustion. Specifically, we hypothesized that among athletes high in gratitude, mastery climate can mitigate the association between performance climate and emotional and physical exhaustion; among those low in gratitude, mastery climate can intensify the association between performance climate and emotional and physical exhaustion. Using a time-lagged survey, data from 293 athletes revealed a three-way interaction effect among mastery climate, performance climate, and gratitude. We did not find that mastery climate can mitigate the association between performance climate and emotional and physical exhaustion for those high in gratitude but found that among athletes low in gratitude, the positive association between performance climate and emotional and physical exhaustion was stronger in a higher mastery climate than in a lower mastery climate. Our study offers an interactionist perspective to help further understand the joint effect of mastery and performance climates on emotional and physical exhaustion by taking the role of individual differences into account.</p

    Recent Outbreak of Dengue in Taiwan

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    In 1987 a dengue outbreak occurred in southern Taiwan, and it persisted throughout the year 1988. Although some cases were reported yearly since then it did not constitute an epidemic as severe as that of 1988. During the period from November 1987 to 30 June 1993, a total of 5,168 serologically or virologically confirmed cases was detected. Of all the cases, 5,085 were considered locally infected, and 83 imported. The proportions of indigenous cases to imported cases were 527 to unknown in 1987, 4,389 to unknown in 1988, 16 to 19 in 1989, 0 to 10 in 1990, 149 to 26 in 1991, 4 to 19 in 1992, and 0 to 9 in 1993. The sources of the imported cases were Thailand (54 cases=65.1%), Philippines (11=13.3%), Singapore (8=9.6%), Indonesia (5=6%), Malaysia (2=2.4%), Vietnam (1=1.2%), India (1=1.2%) and Sri Lanka (1=1.2%). The dengue viruses were isolated both from mosquitoes and humans. Nine D-1 virus isolates were obtained from female mosquitoes of Aedes aegypti among the nine species of mosquitoes collected in houses in 1987 and 1988. The virus isolates from humans were 298 D-1 and 5 D-2 in 1987, 3,534 D-1, 3 D-4 and 1 D-3 in 1988, 5 D-1, 2 D-2 and 1 D-4 in 1989, 1 D-1 and 1 D-2 in 1990, 16 D-1 and 4 D-3 in 1991, and 2 D-1 and 2 D-3 in 1992

    Isoflavones prevent bone loss following ovariectomy in young adult rats

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    Soy protein, a rich source of phytoestrogens, exhibit estrogen-type bioactivity. The purpose of this study was to determine if ingestion of isoflavones before ovariectomy can prevent bone loss following ovariectomy. Twenty-four nulliparous Wistar rats were randomly divided into four groups. In the normal diet groups, a sham operation was performed on Group A, while ovariectomy was performed on Group B. For Groups C and D, all rats were fed with an isoflavone-rich (25 mg/day) diet for one month, then bilateral ovariectomy were performed. In the rats in Group C, a normal diet was begun following the ovariectomy. The rats in Groups D continued to receive the isoflavone-rich diet for two additional months postoperatively. All rats were sacrificed 60 days after surgery. The weight of bone ash of the long bones and whole lumbar spine were determined. A histological study of cancellous bone was done and biochemical indices of skeletal metabolism were performed and analyzed. The markers of bone metabolism exhibited no significant changes. When compared with the sham-operated rats fed a normal diet, the bone mass of ovariectomized rats decreased significantly; pre-ovariectomy ingestion of an isoflavone-rich diet did not prevent bone loss. The bone mass of rats treated with an isoflavone-rich diet for three months was higher than controls two months after ovariectomy

    Isokinetic eccentric exercise can induce skeletal muscle injury within the physiologic excursion of muscle-tendon unit: a rabbit model

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    BACKGROUND AND PURPOSE: Intensive eccentric exercise can cause muscle damage. We simulated an animal model of isokinetic eccentric exercise by repetitively stretching stimulated triceps surae muscle-tendon units to determine if such exercise affects the mechanical properties of the unit within its physiologic excursion. METHODS: Biomechanical parameters of the muscle-tendon unit were monitored during isokinetic eccentric loading in 12 rabbits. In each animal, one limb (control group) was stretched until failure. The other limb (study group) was first subjected to isokinetic and eccentric cyclic loading at the rate of 10.0 cm/min to 112% (group I) or 120% (group II) of its initial length for 1 hour and then stretched to failure. Load-deformation curves and biomechanical parameters were compared between the study and control groups. RESULTS: When the muscle-tendon unit received eccentric cyclic loading to 112%, changes in all biomechanical parameters – except for the slope of the load-deformation curve – were not significant. In contrast, most parameters, including the slope of the load-deformation curve, peak load, deformation at peak load, total energy absorption, and energy absorption before peak load, significantly decreased after isokinetic eccentric cyclic loading to 120%. CONCLUSION: We found a threshold for eccentrically induced injury of the rabbit triceps surae muscle at between 12% and 20% strain, which is within the physiologic excursion of the muscle-tendon units. Our study provided evidence that eccentric exercise may induce changes in the biomechanical properties of skeletal muscles, even within the physiologic range of the excursion of the muscle-tendon unit

    Projected Increase of the East Asian Summer Monsoon (Meiyu) in Taiwan by Climate Models With Variable Performance

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    The active phase of the East Asian summer monsoon (EASM) in Taiwan during May and June, known as Meiyu, produces substantial precipitation for water uses in all sectors of society. Following a companion study that analysed the historical increase in the Meiyu precipitation, the present study conducted model evaluation and diagnosis based on the EASM lifecycle over Taiwan. Higher and lower skill groups were identified from 17 Couple Model Intercomparison Project Phase 5 (CMIP5) models, with five models in each group. Despite the difference in model performance, both groups projected a substantial increase in the Meiyu precipitation over Taiwan. In the higher skill group, weak circulation changes and reduced low‐level convergence point to a synoptically unfavourable condition for precipitation. In the lower skill group, intensified low‐level southwesterly winds associated with a deepened upper level trough enhance moisture pooling. Thus, the projected increase in Meiyu precipitation will likely occur through the combined effects of (1) the extension of a strengthened North Pacific anticyclone enhancing southwesterlies; and (2) more systematically, the Clausius–Clapeyron relationship that increases precipitation intensity in a warmer climate. The overall increase in the Meiyu precipitation projected by climate models of variable performance supports the observed tendency toward more intense rainfall in Taiwan and puts its early June 2017 extreme precipitation events into perspective

    Elevation of hilar mossy cell activity suppresses hippocampal excitability and avoidance behavior

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    Modulation of hippocampal dentate gyrus (DG) excitability regulates anxiety. In the DG, glutamatergic mossy cells (MCs) receive the excitatory drive from principal granule cells (GCs) and mediate the feedback excitation and inhibition of GCs. However, the circuit mechanism by which MCs regulate anxiety-related information routing through hippocampal circuits remains unclear. Moreover, the correlation between MC activity and anxiety states is unclear. In this study, we first demonstrate, by means of calcium fiber photometry, that MC activity in the ventral hippocampus (vHPC) of mice increases while they explore anxiogenic environments. Next, juxtacellular recordings reveal that optogenetic activation of MCs preferentially recruits GABAergic neurons, thereby suppressing GCs and ventral CA1 neurons. Finally, chemogenetic excitation of MCs in the vHPC reduces avoidance behaviors in both healthy and anxious mice. These results not only indicate an anxiolytic role of MCs but also suggest that MCs may be a potential therapeutic target for anxiety disorders
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