328 research outputs found
Time-resolved velocity map imaging of methyl elimination from photoexcited anisole
To date, H-atom elimination from heteroaromatic molecules following UV excitation has been extensively studied, with the focus on key biological molecules such as chromophores of DNA bases and amino acids. Extending these studies to look at elimination of other non-hydride photoproducts is essential in creating a more complete picture of the photochemistry of these biomolecules in the gas-phase. To this effect, CH3 elimination in anisole has been studied using time resolved velocity map imaging (TR-VMI) for the first time, providing both time and energy information on the dynamics following photoexcitation at 200 nm. The extra dimension of energy afforded by these measurements has enabled us to address the role of πσ* states in the excited state dynamics of anisole as compared to the hydride counterpart (phenol), providing strong evidence to suggest that only CH3 fragments eliminated with high kinetic energy are due to direct dissociation involving a 1πσ* state. These measurements also suggest that indirect mechanisms such as statistical unimolecular decay could be contributing to the dynamics at much longer times
Youth unemployment, firm size and reservation wages in South Africa
Youth unemployment in South Africa is high. We investigate whether one of the reasons may be that the wages young people want or need are above those that they could reasonably expect to earn given their characteristics. Unlike previous work on the relationship between reservation wages and unemployment we differentiate between wages in different sizes of firms. Larger firms pay more and thus, even if reservation wages are similar to average predicted wages they may be above wages that young people could expect to earn in smaller firms. We find that this is the case.Youth unemployment, firm size, reservation wages, South Africa
The strong weak convergence of the quasi-EA
In this paper, we investigate the convergence of a novel simulation scheme to the target diffusion process. This scheme, the Quasi-EA, is closely related to the Exact Algorithm (EA) for diffusion processes, as it is obtained by neglecting the rejection step in EA. We prove the existence of a myopic coupling between the Quasi-EA and the diffusion. Moreover, an upper bound for the coupling probability is given. Consequently we establish the convergence of the Quasi-EA to the diffusion with respect to the total variation distance
Youth unemployment, firm size and reservation wages in South Africa
Youth unemployment in South Africa is high. We investigate whether one of the reasons may be that the wages young people want or need are above those that they could reasonably expect to earn given their characteristics. Unlike previous work on the relationship between reservation wages and unemployment we differentiate between wages in different sizes of firms. Larger firms pay more and thus, even if reservation wages are similar to average predicted wages they may be above wages that young people could expect to earn in smaller firms. We find that this is the case
Youth unemployment, firm size and reservation wages in South Africa
Youth unemployment in South Africa is high. We investigate whether one of the reasons may be that the wages young people want or need are above those that they could reasonably expect to earn given their characteristics. Unlike previous work on the relationship between reservation wages and unemployment we differentiate between wages in different sizes of firms. Larger firms pay more and thus, even if reservation wages are similar to average predicted wages they may be above wages that young people could expect to earn in smaller firms. We find that this is the case
Predictors of military veterans' engagement in bespoke recovery pathways and health and well-being outcomes
Purpose/Objective: The objective of this cross-sectional study was to assess how psychosocial variables predict U.K. military veterans’ level of engagement in bespoke recovery pathways (Aim 1) and a sportsspecific recovery pathway (Aim 2). A further purpose of this study was to test whether predictor variables indirectly predict outcome variables of physical health (Aim 3), mental health (Aim 4), and subjective vitality (Aim 5), when mediated through level of engagement with all recovery pathways and the sport recovery pathway. Research Method/Design: A cross-sectional battery of questionnaires were completed by 514 military veterans who had been enrolled in Help for Heroes recovery pathways (e.g., sports recovery pathway) from 3 months to 10 years. Data were analyzed by multinomial logistic and multiple linear regressions and mediation analyses using the PROCESS SPSS macro. Results: Engagement in all recovery pathways (i.e., frequency and duration of attendance) was predicted by basic psychological needs frustration and perceived social support (Nagelkerke R 2 =.16). Sport-related social support (p <.05) and competence satisfaction (p <.001) were directly positively associated with mental health, and competence satisfaction with physical health (p <.001) and well-being (p,.001) on the sport recovery pathway. While perceived stress was directly negatively associated with mental health and well-being (p <.001). Mediation analyses revealed no significant, indirect effects of psychosocial variables on health and wellbeing through level of engagement. Conclusions/Implications: In sum, engagement in recovery pathways does not mediate the effects of psychosocial variables on veterans’ health and well-being. Perceived social support, satisfaction of veterans’ needs, and perceived stress were better predictors of health and well-being outcomes and should be an important focus of future research and recovery. </p
Networks and the epidemiology of infectious disease
The science of networks has revolutionised research into the dynamics of interacting elements. It could be argued that epidemiology in particular has embraced the potential of network theory more than any other discipline. Here we review the growing body of research concerning the spread of infectious diseases on networks, focusing on the interplay between network theory and epidemiology. The review is split into four main sections, which examine: the types of network relevant to epidemiology; the multitude of ways these networks can be characterised; the statistical methods that can be applied to infer the epidemiological parameters on a realised network; and finally simulation and analytical methods to determine epidemic dynamics on a given network. Given the breadth of areas covered and the ever-expanding number of publications, a comprehensive review of all work is impossible. Instead, we provide a personalised overview into the areas of network epidemiology that have seen the greatest progress in recent years or have the greatest potential to provide novel insights. As such, considerable importance is placed on analytical approaches and statistical methods which are both rapidly expanding fields. Throughout this review we restrict our attention to epidemiological issues
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