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61.
Purpose: Marital dissatisfaction and conflict often increase for couples after the birth of a child and are evident in fewer positive family interactions and more negative family interactions. Because exercise is known to increase positive emotions and decrease negative emotions, the current study examined the extent to which higher levels of mothers’ exercise during the postpartum period were related to more positive and fewer negative emotion-expressive behaviors with their infants’ fathers. Method: Mothers’ (N = 46; M = 8 months postpartum) positive and negative expressive behaviors were coded during couples’ discussions of current conflict and positive family experiences. Mothers self-reported their leisure-time exercise behavior. Results: First-time mothers and mothers with higher levels of leisure-time exercise behavior displayed higher levels of positive expressive behaviors during couples’ discussions. Conclusions: Exercise may be associated with increased positive emotion and, in turn, can have great potential to improve family relationships during the postpartum period when marital stress normatively increases, particularly for mothers with more than 1 child. Future longitudinal studies are needed to understand exercise patterns across the postpartum period to identify the most effective timing and optimal level of exercise that lead to more positive expressive behaviors.  相似文献   
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Compared to competitive runners, recreational runners appear to be more prone to injuries, which have been associated with foot strike patterns. Surprisingly, only few studies had examined the foot strike patterns outside laboratories. Therefore, this study compared the foot strike patterns in recreational runners at outdoor tracks with previously reported data. We also investigated the relationship between foot strike pattern, speed, and footwear in this cohort. Among 434 recreational runners analysed, 89.6% of them landed with rearfoot strike (RFS). Only 6.9 and 3.5% landed with midfoot and forefoot, respectively. A significant shift towards non-RFS was observed in our cohort, when compared with previously reported data. When speed increased by 1 m/s, the odds of having forefoot strike and midfoot strike relative to RFS increased by 2.3 times and 2.6 times, respectively. Runners were 9.2 times more likely to run with a forefoot strike in minimalists compared to regular running shoes, although 70% of runners in minimalists continued to use a RFS. These findings suggest that foot strike pattern may differ across running conditions and runners should consider these factors in order to mitigate potential injury.  相似文献   
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The practice of sexting is becoming increasingly common among college students but has the potential to both initiate productive interactions with others and interfere with relationship development. The purpose of this paper is to report on the findings of a study on sexting among college students and to provide a framework through which practitioners working with this population would be able to effectively intervene. Implications for clinical practice include more specific assessment questions for practitioners, focus on better managing riskier behavior, and guidance toward using technology in relationally responsible and supportive ways.  相似文献   
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When designing lossless networks, one is faced with the problem of choosing a zero configuration for the reflection coefficient ?(s). Bode showed that if parasitic capacitances are present as well as for power transfer optimization, the best zero configuration is to locate all of them in the left half-plane. Recently, Bode's result was generalized to include parasitic immitances at both ends (source and load) of the quadripole.This work adds a new result to the theory by looking at the overall transfer function poles. It is shown that (a) if the source resistance varies, one should select left half-plane zeros for ?(s); and (b) if the load impedance varies, one should select right half-plane zeros.The pole sensitivity criterion used is the distance between the actual transfer function poles and the poles of the ideal transfer function.  相似文献   
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