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21.
We construct a model where incumbents can either acquire basic innovations from entrepreneurs, or wait and acquire developed innovations from entrepreneurial firms supported by venture capitalists. We show that venture‐backed entrepreneurial firms have an incentive to overinvest in development vis à vis incumbents due to strategic product market effects on the sales price of a developed innovation. This will trigger preemptive acquisitions by incumbents, thus increasing the reward for entrepreneurial innovations. We also show that venture capital can emerge in equilibrium if venture capitalists have cost advantages, or if development is associated with double moral hazard problems. (JEL: G24, L1, L2, M13, O3)  相似文献   
22.
Lundberg O, Fritzell J, Åberg Yngwe M, Kölegård ML. The potential power of social policy programmes: income redistribution, economic resources and health Int J Soc Welfare 2010: ??: ??–??© 2010 The Author(s), Journal compilation © 2010 Blackwell Publishing Ltd and International Journal of Social Welfare. This Supplement includes a number of articles dealing with the role of social policy schemes for public health across the life course. As a key social determinant of health, poverty and its consequences have historically been at the forefront of the public health discussion. But also in rich countries today, economic resources are likely to be important for health and survival, both on an individual and an aggregate level. This introductory article serves as a background for the more specific analyses that follow. The focus is on why income and income inequality could have an effect on individual and population health. We discuss relationships between the individual and population levels and between income and health, and some of the possible mechanisms involved. We also present arguments for why welfare state institutions may matter.  相似文献   
23.
Foster children often have behavioural problems. Behavioural problems influence the level of parenting stress and can lead to a breakdown. In this study, parenting behaviour of foster mothers is mapped, and the influence of behavioural problems and parenting stress on the parenting behaviour 2 years later is examined. Data of behavioural problems, family stress and parenting were gathered from 49 foster mothers. Problem behaviour has a direct negative impact on parenting and leads to less support and more negative control. It also results in more parenting stress. Foster parents need to be trained aiming at preventing ineffective parenting. The well‐being of foster parents needs to be guarded. Higher levels of parenting stress lead to less effective parenting.  相似文献   
24.
Family foster care is the option of choice for children in need of out‐of‐home care in Flanders and the Netherlands. Foster care is however a vulnerable intervention, and questions can be raised as to its efficacy. Although the literature on placement breakdown has made significant progress during the last years, empirical knowledge regarding breakdown in Flanders and the Netherlands remains scant. Consequently, this study aimed at investigating prevalence and precursors of breakdowns in long‐term foster care, the duration of placement before breakdown, and the association of child and placement characteristics with breakdown. Case files of 271 Dutch and 309 Flemish foster children were analysed with a coding scheme designed for this study. After 6 years, 398 placements had terminated: 169 placements broke down and 229 placements ended positively. Placements broke down mainly because of behavioural problems of the foster child, foster parents' parenting problems, and conflicts between birth and foster parents. Foster children with behavioural problems, older foster children, foster children denied treatment, and foster children in care because of sexual abuse were more at risk of breakdown. Assessing these factors is important when evaluating the appropriateness of a family foster care placement.  相似文献   
25.
Missing data methods, maximum likelihood estimation (MLE) and multiple imputation (MI), for longitudinal questionnaire data were investigated via simulation. Predictive mean matching (PMM) was applied at both item and scale levels, logistic regression at item level and multivariate normal imputation at scale level. We investigated a hybrid approach which is combination of MLE and MI, i.e. scales from the imputed data are eliminated if all underlying items were originally missing. Bias and mean square error (MSE) for parameter estimates were examined. ML seemed to provide occasionally the best results in terms of bias, but hardly ever on MSE. All imputation methods at the scale level and logistic regression at item level hardly ever showed the best performance. The hybrid approach is similar or better than its original MI. The PMM-hybrid approach at item level demonstrated the best MSE for most settings and in some cases also the smallest bias.  相似文献   
26.
Conditional cash transfers (CCTs) are often being promoted for their simultaneous advantages of short‐term income protection and long‐term human capital investments. Yet, existing evaluations have largely failed to test the underlying programme theory, and few empirical case studies have explored inherent contradictions and ambiguous consequences of this hybrid approach. To further understand the programmes' social policy implications, this study identifies and analyzes such ambiguities and paradoxical consequences in the case of Uruguay's CCT‐programme, Asignaciones Familiares (AFAM). Drawing on qualitative data from interviews with beneficiaries and members of the commission who designed the programme, this study reveals major paradoxes in AFAM's design and implementation caused by various endogenous factors. Relevant to social policy in general, and CCT‐evaluations in particular, findings also indicate that the hybrid social assistance approach may have perverse effects on the programme's twin objectives.  相似文献   
27.
Extreme-value copulas arise in the asymptotic theory for componentwise maxima of independent random samples. An extreme-value copula is determined by its Pickands dependence function, which is a function on the unit simplex subject to certain shape constraints that arise from an integral transform of an underlying measure called spectral measure. Multivariate extensions are provided of certain rank-based nonparametric estimators of the Pickands dependence function. The shape constraint that the estimator should itself be a Pickands dependence function is enforced by replacing an initial estimator by its best least-squares approximation in the set of Pickands dependence functions having a discrete spectral measure supported on a sufficiently fine grid. Weak convergence of the standardized estimators is demonstrated and the finite-sample performance of the estimators is investigated by means of a simulation experiment.  相似文献   
28.
Information and communication technologies hold much promise for use in education in developing countries. This study reports on an evaluation conducted on the introduction of computers in the delivery of the mathematics curriculum in one of the provinces of South Africa. Although the request was for an outcome evaluation very early in the implementation of the program, it was tailored in such a way as to fulfill a more formative role. Despite substantial variability in implementation, and in most cases with very weak exposure of the learners to the intervention, sufficient evidence emerged to indicate that this mode of curriculum delivery may be effective. Improvement in mathematics performance was related to a range of variables: some concerned classroom teaching practices, some referred to social differences between the learners, and some to the specific intervention. The strongest of these predictors in the sample was the strength of the intervention: the more time learners spent on using the software to study mathematics, the more improvement they showed from 1 year to the next in their performance in the subject.  相似文献   
29.
The aim of this article is to provide an overview of the current literature on the impact of the metabolic syndrome on male sexual health and current developments in the management of sexually dysfunctional men with a metabolic syndrome. The increasing prevalence across the world of the metabolic syndrome-a cluster of cardiovascular disease risk factors-causes the metabolic syndrome to be considered the most important threat to male sexual health of the 21st century. It has been shown to have a negative impact on male sexual function through its relationship with cardiovascular disease risk, its association with hypogonadism, and associated psychosocial factors. Besides established pharmacological and hormonal interventions, lifestyle modification programs are considered important therapeutic tools.  相似文献   
30.
Abstract

This paper contributes to the relatively sparse knowledge about relationships between stressful work environments and bullying. Relationships between job stressors and leadership behaviour were analysed as possible predictors of bullying at work on the basis of the work environment hypothesis, which states that stressful and poorly organized work environments may give rise to conditions resulting in bullying. Analyses of a representative sample (n=2539) of the Norwegian workforce showed role conflict, interpersonal conflicts, and tyrannical and laissez-faire leadership behaviour to be strongly related to bullying, and that the strength of associations to a high degree differed for various measures of bullying. Support was found for an interactive relationship between decision authority and role conflict at different levels of laissez-faire leadership. Not only targets and bully/targets but also bystanders assessed their work environment more negatively than did non-involved employees, while perpetrators of bullying did not differ significantly from non-involved employees as regards their perception of the work environment. Hence, bullying is likely to prevail in stressful working environments characterized by high levels of interpersonal friction and destructive leadership styles. In addition, bullying is particularly prevalent in situations where the immediate supervisor avoids intervening in and managing such stressful situations.  相似文献   
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