The effects of a plyometric training program on the latency time of the quadriceps femoris and gastrocnemius short-latency responses

Aim: The purpose of this study was to determine if a plyometric training program can affect the latency time of the quadriceps femoris and gastrocnemius short-latency responses (SLRs) of the stretch reflex. Methods: Sixteen healthy subjects (12 female and 4 male) were randomly assigned to either a control or a plyometric training group. Maximum vertical jump height (VJ) and SLRs of both quadriceps femoris and gastrocnemius were measured before and after a four week plyometric training program. Results: Plyometric training significantly increased VJ (mean+/-SEM) by 2.38+/-0.45 cm (P\u3c0.05) and non-significantly decreased the latency time of the quadriceps femoris SLR (mean+/-SEM) 0.363+/-0.404 ms (P\u3e0.05) and gastrocnemius SLR (mean+/-SEM) 0.392+/-0.257 ms (P\u3e0.05). VJ results support the effectiveness of plyometric training for increasing VJ height. Conclusions:The non-significant changes in the latency time of the quadriceps femoris and gastrocnemius SLRs seen in the training group suggest that performance improvements following a four-week plyometric training program are not mediated by changes in the latency time of the short-latency stretch reflex

The unified protocol for transdiagnostic treatment of emotional disorders compared with diagnosis-specific protocols for anxiety disorders a randomized clinical trial

IMPORTANCE: Transdiagnostic interventions have been developed to address barriers to the dissemination of evidence-based psychological treatments, but only a few preliminary studies have compared these approaches with existing evidence-based psychological treatments. OBJECTIVE: To determine whether the Unified Protocol for Transdiagnostic Treatment of Emotional Disorders (UP) is at least as efficacious as single-disorder protocols (SDPs) in the treatment of anxiety disorders. DESIGN, SETTING, AND PARTICIPANTS: From June 23, 2011, to March 5, 2015, a total of 223 patients at an outpatient treatment center with a principal diagnosis of panic disorder with or without agoraphobia, generalized anxiety disorder, obsessive-compulsive disorder, or social anxiety disorder were randomly assigned by principal diagnosis to the UP, an SDP, or a waitlist control condition. Patients received up to 16 sessions of the UP or an SDP for 16 to 21 weeks. Outcomes were assessed at baseline, after treatment, and at 6-month follow-up. Analysis in this equivalence trial was based on intention to treat. INTERVENTIONS: The UP or SDPs. MAIN OUTCOMES AND MEASURES: Blinded evaluations of principal diagnosis clinical severity rating were used to evaluate an a priori hypothesis of equivalence between the UP and SDPs. RESULTS: Among the 223 patients (124 women and 99 men; mean [SD] age, 31.1 [11.0] years), 88 were randomized to receive the UP, 91 to receive an SDP, and 44 to the waitlist control condition. Patients were more likely to complete treatment with the UP than with SDPs (odds ratio, 3.11; 95% CI, 1.44-6.74). Both the UP (Cohen d, −0.93; 95% CI, −1.29 to −0.57) and SDPs (Cohen d, −1.08; 95% CI, −1.43 to −0.73) were superior to the waitlist control condition at acute outcome. Reductions in clinical severity rating from baseline to the end of treatment (β, 0.25; 95% CI, −0.26 to 0.75) and from baseline to the 6-month follow-up (β, 0.16; 95% CI, −0.39 to 0.70) indicated statistical equivalence between the UP and SDPs. CONCLUSIONS AND RELEVANCE: The UP produces symptom reduction equivalent to criterion standard evidence-based psychological treatments for anxiety disorders with less attrition. Thus, it may be possible to use 1 protocol instead of multiple SDPs to more efficiently treat the most commonly occurring anxiety and depressive disorders.This study was funded by grant R01 MH090053 from the National Institute of Mental Health. (R01 MH090053 - National Institute of Mental Health)First author draf

Tradable Pollution Permits and the Regulatory Game

This paper analyzes polluters\u27 incentives to move from a traditional command and control (CAC) environmental regulatory regime to a tradable permits (TPP) regime. Existing work in environmental economics does not model how firms contest and bargain over actual regulatory implementation in CAC regimes, and therefore fail to compare TPP regimes with any CAC regime that is actually observed. This paper models CAC environmental regulation as a bargaining game over pollution entitlements. Using a reduced form model of the regulatory contest, it shows that CAC regulatory bargaining likely generates a regulatory status quo under which firms with the highest compliance costs bargain for the smallest pollution reductions, or even no reduction at all. As for a tradable permits regime, it is shown that all firms are better off under such a regime than they would be under an idealized CAC regime that set and enforced a uniform pollution standard, but permit sellers (low compliance cost firms) may actually be better off under a TPP regime with relaxed aggregate pollution levels. Most importantly, because high cost firms (or facilities) are the most weakly regulated in the equilibrium under negotiated or bargained CAC regimes, they may be net losers in a proposed move to a TPP regime. When equilibrium costs under a TPP regime are compared with equilibrium costs under a status quo CAC regime, several otherwise paradoxical aspects of firm attitudes toward TPP type reforms can be explained. In particular, the otherwise paradoxical pattern of allowances awarded under Phase II of the 1990 Clean Air Act\u27s acid rain program, a pattern tending to favor (in Phase II) cleaner, newer generating units, is explained by the fact that under the status quo regime, a kind of bargained CAC, it was the newer cleaner units that were regulated, and which therefore had higher marginal control costs than did the largely unregulated older, plants. As a normative matter, the analysis here implies that the proper baseline for evaluating TPP regimes such as those contained in the Bush Administration\u27s recent Clear Skies initiative is not idealized, but nonexistent CAC regulatory outcomes, but rather the outcomes that have resulted from the bargaining game set up by CAC laws and regulations

Anarchy's anatomy : two-tiered security systems and Libya’s civil wars

No issue deserves more scrutiny than the mechanisms whereby popular unrest unleashes civil wars. We argue that one institution — two-tiered security systems — is particularly pernicious in terms of the accompanying civil war risk. These systems’ defining characteristic is the juxtaposition of small communally stacked units that protect regimes from internal adversaries with larger regular armed forces that deter external opponents. These systems aggravate civil war risks because stacked security units lack the size to repress widespread dissent, but inhibit rapid regime change through coup d’état. Regular militaries, meanwhile, fracture when ordered to employ force against populations from which they were recruited.PostprintPeer reviewe

The Empirics of China’s Outward Direct Investment

We investigate the empirical determinants of China's outward direct investment (ODI). It is found that China's investments in developed and developing countries are driven by different sets of factors. Subject to the differences between developed and developing countries, there is evidence that a) both market seeking and resources seeking motives drive China's ODI, b) the Chinese exports to developing countries induce China's ODI, c) China's international reserves promote its ODI, and d) the Chinese capital tends to agglomerate among developed economies but diversify among developing economies. Similar results are obtained using alternative ODI data. We do not find substantial evidence that China invests in African and oil-producing countries mainly for their natural resources

Effectiveness and acceptability of progestogens in combined oral contraceptives – a systematic review

BACKGROUND: The progestogen component of oral contraceptives (OCs) has undergone changes since it was recognized that their chemical structure can influence the spectrum of minor adverse and beneficial effects. METHODS: The objective of this review was to evaluate currently available low-dose OCs containing ethinylestradiol and different progestogens in terms of contraceptive effectiveness, cycle control, side effects and continuation rates. The Cochrane Controlled Trials Register, MEDLINE and EMBASE databases were searched. Randomized trials reporting clinical outcomes were considered for inclusion and were assessed for methodological quality and validity. RESULTS: Twenty–two trials were included in the review. Eighteen were sponsored by pharmaceutical companies and in only 5 there was an attempt for blinding. Most comparisons between different interventions included one to three trials, involving usually less than 500 women. Discontinuation was less with second-generation progestogens compared to first–generation (RR 0.79; 95% CI 0.69–0.91). Cycle control appeared to be better with second-compared to first-generation progestogens for both, mono-and triphasic preparations (RR 0.69; 95% CI 0.52–0.91) and (RR 0.61; 95% CI 0.43–0.85), respectively. Intermenstrual bleeding was less with third- compared to second-generation pills (RR 0.71; 95% CI 0.55–0.91). Contraceptive effectiveness of gestodene (GSD) was comparable to that of levonorgestrel (LNG), and had similar pattern of spotting, breakthrough bleeding and absence of withdrawal bleeding). Drospirenone (DRSP) was similar compared to desogestrel (DSG) regarding contraceptive effectiveness, cycle control and side effects. CONCLUSION: The third- and second-generation progestogens are preferred over first generation in all indices of acceptability. Current evidence suggests that GSD is comparable to LNG in terms of contraceptive effectiveness and for most cycle control indices. GSD is also comparable to DSG. DRSP is comparable to DSG. Future research should focus on independently conducted well designed randomized trials comparing particularly the third- with second-generation progestogens