808 resultados para Peer-to-peer markets
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This study explored the links between having older siblings who get drunk, satisfaction with the parent-adolescent relationship, parental monitoring, and adolescents' risky drinking. Regression models were conducted based on a national representative sample of 3725 8th to 10th graders in Switzerland (mean age 15.0, SD = .93) who indicated having older siblings. Results showed that both parental factors and older siblings' drinking behaviour shape younger siblings' frequency of risky drinking. Parental monitoring showed a linear dose-response relationship, and siblings' influence had an additive effect. There was a non-linear interaction effect between parent-adolescent relationship and older sibling's drunkenness. The findings suggest that, apart from avoiding an increasingly unsatisfactory relationship with their children, parental monitoring appears to be important in preventing risky drinking by their younger children, even if the older sibling drinks in such a way. However, a satisfying relationship with parents does not seem to be sufficient to counterbalance older siblings' influence.
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The goal of this paper is to estimate time-varying covariance matrices.Since the covariance matrix of financial returns is known to changethrough time and is an essential ingredient in risk measurement, portfolioselection, and tests of asset pricing models, this is a very importantproblem in practice. Our model of choice is the Diagonal-Vech version ofthe Multivariate GARCH(1,1) model. The problem is that the estimation ofthe general Diagonal-Vech model model is numerically infeasible indimensions higher than 5. The common approach is to estimate more restrictive models which are tractable but may not conform to the data. Our contributionis to propose an alternative estimation method that is numerically feasible,produces positive semi-definite conditional covariance matrices, and doesnot impose unrealistic a priori restrictions. We provide an empiricalapplication in the context of international stock markets, comparing thenew estimator to a number of existing ones.
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In Duchenne muscular dystrophy (DMD), a persistently altered and reorganizing extracellular matrix (ECM) within inflamed muscle promotes damage and dysfunction. However, the molecular determinants of the ECM that mediate inflammatory changes and faulty tissue reorganization remain poorly defined. Here, we show that fibrin deposition is a conspicuous consequence of muscle-vascular damage in dystrophic muscles of DMD patients and mdx mice and that elimination of fibrin(ogen) attenuated dystrophy progression in mdx mice. These benefits appear to be tied to: (i) a decrease in leukocyte integrin α(M)β(2)-mediated proinflammatory programs, thereby attenuating counterproductive inflammation and muscle degeneration; and (ii) a release of satellite cells from persistent inhibitory signals, thereby promoting regeneration. Remarkably, Fib-gamma(390-396A) (Fibγ(390-396A)) mice expressing a mutant form of fibrinogen with normal clotting function, but lacking the α(M)β(2) binding motif, ameliorated dystrophic pathology. Delivery of a fibrinogen/α(M)β(2) blocking peptide was similarly beneficial. Conversely, intramuscular fibrinogen delivery sufficed to induce inflammation and degeneration in fibrinogen-null mice. Thus, local fibrin(ogen) deposition drives dystrophic muscle inflammation and dysfunction, and disruption of fibrin(ogen)-α(M)β(2) interactions may provide a novel strategy for DMD treatment.
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AIM: The study aims to evaluate the effects of assertive community treatment (ACT) on the mental health and overall functioning of adolescents suffering from severe psychiatric disorders and who refuse any traditional child psychiatric care. There are a few studies evaluating the effects of ACT on a population of adolescents with psychiatric disorders. This short report highlights the impact of an ACT programme tailored to the needs of these patients, not only as an alternative to hospitalization, but also as a new form of intervention for patients that are difficult to engage. METHODS: The effect of ACT on 35 adolescents using the Health of the Nation Outcome Scales for Children and Adolescents (HoNOSCA) as a measuring tool in pre- and post-intervention was evaluated. RESULTS: The results show that the intervention was associated with a significant improvement on the HoNOSCA overall score, with the following items showing significant amelioration: hyperactivity/focus problems, non-organic somatic symptoms, emotional symptoms, scholastic/language skills, peer relationships, family relationships and school attendance. CONCLUSION: ACT appears as a feasible intervention for hard-to-engage adolescents suffering from psychiatric disorders. The intervention seems to improve their mental health and functioning. This pilot study may serve as a basis to prepare a controlled study that will also take the costs of the intervention into account.
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Empirical studies indicate that the transition to parenthood is influenced by an individual's peer group. To study the mechanisms creating interdepen- dencies across individuals' transition to parenthood and its timing we apply an agent-based simulation model. We build a one-sex model and provide agents with three different characteristics regarding age, intended education and parity. Agents endogenously form their network based on social closeness. Network members then may influence the agents' transition to higher parity levels. Our numerical simulations indicate that accounting for social inter- actions can explain the shift of first-birth probabilities in Austria over the period 1984 to 2004. Moreover, we apply our model to forecast age-specific fertility rates up to 2016.
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The objective of this research was to determine whether the level of parental monitoring is associated with substance use among adolescents in Switzerland, and to assess whether this effect remains when these adolescents have consuming peers. For this purpose, we used a nationally representative sample from the Swiss participation in the 2007 European School Project on Alcohol and Other Drugs survey, which included 7,611 adolescents in public schools (8th-10th grades). Four levels of parental control were created and four substances (tobacco, alcohol, cannabis, and ecstasy) were analyzed. All significant variables at the bivariate level were included in the multivariate analysis. Most adolescents had a high level of parental monitoring and that was associated with younger age, females, high socioeconomic status, intact family structure, and satisfactory relationships with mother, father, and peers. Overall, substance use decreased as parental monitoring increased and high parental monitoring decreased as having consuming peers increased. Results remained essentially the same when the variable "having consuming peers" was added to the analysis. Conclusion: parental monitoring is associated to positive effects on adolescent substance use with a reduction of consumption and a lower probability of having consuming peers, which seems to protect adolescents against potentially negative peer influence. Encouraging parents to monitor their adolescents' activities and friendships by establishing rules about what is allowed or not is a way to limit the negative influence of consuming peers on adolescent substance use.
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Drinking habits are socially patterned and social networks influence individuals' drinking behaviors. Previous studies have focused primarily upon the influence from family members to drink less. Those studies that have focused upon peer influence have been largely confined to social norms among adolescent and college-age drinkers. By contrast, based in adult populations, this article examines exhortations from friends not only to reduce alcohol consumption but also to increase it. Survey data in 15 countries that participate in the Gender, Alcohol and Culture: An International Study project (GENACIS) were used to test whether there were country and gender differences concerning the influence to drink less or to drink more by friends and examine if this was affected by the drinking behavior. The findings revealed that those influenced to drink less had more heavy episodic drinking (HED) occasions than those who did not report such influence. By contrast, influence to drink more, originating mainly from same-sex friends, may be more the result of social situations that encourage all drinkers, regardless of their frequency of HED occasions. At the country level, influence to drink less for both sexes decreased with the proportion of drinkers in a country. Similarly, influence to drink less for both sexes also decreased in countries where gender roles were more egalitarian. Thus, in countries where alcohol use is more widespread and fewer differences are observed between male and female gender role expectations, fewer people were influenced to drink less. These findings have implications for social and behavioral strategies designed to reduce alcohol-related harm across a wide range of cultures.
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Peer-reviewed
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Peer-reviewed
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This paper describes the port interconnection of two subsystems: a power electronics subsystem (a back-to-back AC/CA converter (B2B), coupled to a phase of the power grid), and an electromechanical subsystem (a doubly-fed induction machine (DFIM). The B2B is a variable structure system (VSS), due to presence of control-actuated switches: however, from a modelling simulation, as well as a control-design, point of view, it is sensible to consider modulated transformers (MTF in the bond graph language) instead of the pairs of complementary switches. The port-Hamiltonian models of both subsystems are presented and, using a power-preserving interconnection, the Hamiltonian description of the whole system is obtained; detailed bond graphs of all subsystems and the complete system are also provided. Using passivity-based controllers computed in the Hamiltonian formalism for both subsystems, the whole model is simulated; simulations are run to rest the correctness and efficiency of the Hamiltonian network modelling approach used in this work.