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41.
In this diary study, we examined a theoretical model in which the psychological conditions of meaningfulness, availability, and safety serve as mechanisms through which the work context during discrete situations within the workday influences “state” engagement. We further theorised that a person's “trait” level of engagement would exert cross‐level effects on the state level relationships. Multilevel analyses based on a sample of 124 individuals in six organisations and 1,446 situational observations revealed that meaningfulness and availability (but not safety) mediated the relationships between perceptions of the work context and state engagement. High levels of trait engagement strengthened the within‐person relation between availability and state engagement, yet weakened the within‐person relation between meaningfulness and state engagement, suggesting two different processes may be at play. Overall, the findings advance our understanding of engagement as a multilevel and temporally dynamic psychological phenomenon and promote a contextually based HRM approach to facilitating engagement.  相似文献   
42.
Consider N independent stochastic processes \((X_i(t), t\in [0,T])\), \(i=1,\ldots , N\), defined by a stochastic differential equation with random effects where the drift term depends linearly on a random vector \(\Phi _i\) and the diffusion coefficient depends on another linear random effect \(\Psi _i\). For these effects, we consider a joint parametric distribution. We propose and study two approximate likelihoods for estimating the parameters of this joint distribution based on discrete observations of the processes on a fixed time interval. Consistent and \(\sqrt{N}\)-asymptotically Gaussian estimators are obtained when both the number of individuals and the number of observations per individual tend to infinity. The estimation methods are investigated on simulated data and show good performances.  相似文献   
43.
This paper examines whether there is a relationship between the commodity terms of trade (the price of primary commodities relative to the price of manufactures) and the net barter terms of trade of 42 Sub-Saharan African countries. For most countries, there is little evidence of a stable, long-run relationship between the two terms of trade series. Accordingly, the practice in the literature of proxying for movements in any given country's terms of trade by using an aggregate index of relative commodity prices is inappropriate, and is likely to engender misleading policy conclusions.  相似文献   
44.
Drug abuse treatment has been pervasive in the US in the recent years, and the associated direct treatment costs approached $18 billion in 2001. However, there have been few published studies on scale economies, and none on scope economies, for drug abuse treatment costs. We estimate a restricted cost function for 17 hospitals in Washington State that provided inpatient and/or outpatient drug abuse treatment during the years 1997–2004. We find significant evidence of scale economies for hospitals that provide only outpatient drug abuse treatment services. The marginal costs of outpatient services are even smaller for hospitals that produce both outpatient and inpatient drug abuse treatment services. Further, these joint-production hospitals exhibit diseconomies of scope, or specialization economies. These results all imply that recent trends towards additional outpatient treatment services will enhance cost efficiency.  相似文献   
45.
The development of accurate non-point source pollution assessment technologies allows the implementation of more efficient policies than can be undertaken in their absence. This study estimates the value of accurate measurement technology by estimating the gains from implementing a more efficient policy, one that targets agricultural non-point source emission reductions at the field scale but requires accurate field scale measurement technology, relative to a practice-based policy that can be implemented in the absence of such technology. For the environmental benefit of carbon sequestration, large cost savings are found due to improved targeting of conservation tillage subsidies for the state of Iowa. The ability of the government to cost discriminate is found to have little impact on the value of accurate measurement technology.  相似文献   
46.
Michael Porter, the influential Harvard management guru, has promoted the idea that compliance with stricter environmental regulations can afford secondary benefits to firms through improved product design, innovation, corporate morale and in other ways. Once these secondary benefits are factored, the net cost of compliance is argued to be lower than conventionally thought and may even be negative. Whilst environmental economists have rejected the Porter Hypothesis as being based on excessively optimistic expectations of the likely size of such secondary benefits the underlying ideas do enjoy significant credence in the business community. In the context of a lobbying model of regulatory policy-making we argue that the EPA should change the way it conducts regulatory policy to take account of Porter's views – even if it knows those views to be misguided. The model serves to illustrate the more general point that fashions in management thinking can be expected to impact the optimal conduct of regulatory policy.  相似文献   
47.
Improved crop–fallow systems in the humid tropics can simultaneously sequester atmospheric carbon emissions and contribute to sustainable livelihoods of rural populations. A study with an indigenous community in eastern Panama revealed a considerable biophysical potential for carbon offsets in small-scale slash-and-burn agriculture through longer fallow periods, improved fallow management, secondary forest development, and agricultural intensification. Based on soil and biomass carbon measurements, estimated annual sequestration rates amount to 0.3−3.7 t C ha− 1 yr− 1. Despite such potential, the economic benefits of initiatives aimed at sequestration of carbon in the community are likely to be rather unequally distributed within the community. Heterogeneity in livelihood strategies and uneven asset endowments among households – factors often overlooked in the ongoing carbon and sustainable development debate – are expected to strongly affect household participation. Indeed, only the better-endowed households that have also managed to diversify into more lucrative farm and non-farm activities are likely to be able to participate in and thus benefit from improved crop–fallow systems that capture carbon. Economic, ethical, institutional, and technical concerns need to be taken into account when designing community carbon management and investment plans.  相似文献   
48.
Background: A phase III trial evaluated the efficacy and safety of Daklinza (daclatasvir or DCV) in combination with sofosbuvir (SOF) for treatment of genotype (GT) 3 hepatitis C virus (HCV) patients.

Aim: This study evaluated the cost-effectiveness of DCV?+?SOF vs SOF in combination with ribavirin (RBV) over a 20-year time horizon from the perspective of a United States (US) payer.

Methods: A published Markov model was adapted to reflect US demographic characteristics, treatment patterns, costs of drug acquisition, monitoring, disease and adverse event management, and mortality risks. Clinical inputs came from the ALLY-3 and VALENCE trials. The primary outcome was the incremental cost-utility ratio. Life-years, incidence of complications, number of patients achieving sustained virological response (SVR), and the total cost per SVR were secondary outcomes. Costs (2014 USD) and quality-adjusted life years (QALYs) were discounted at 3% per year. Deterministic, probabilistic, and scenario sensitivity analyses were conducted.

Results: DCV?+?SOF was associated with lower costs and better effectiveness than SOF?+?RBV in the base case and in almost all scenarios (i.e. treatment-experienced, non-cirrhotic, time horizons of 5, 10, and 80 years). DCV?+?SOF was less costly, but also slightly less effective than SOF?+?RBV in the cirrhotic and treatment-naïve population scenarios. Results were sensitive to variations in the probability of achieving SVR for both treatment arms. DCV?+?SOF costs less than $50,000 per QALY gained in 79% of all probabilistic iterations compared with SOF?+?RBV.

Conclusion: DCV?+?SOF is a dominant option compared with SOF?+?RBV in the US for the overall GT 3 HCV patient population.  相似文献   
49.
Abstract

This paper discusses why mathematical economists of the early Cold War period favored formal-axiomatic over behavioral choice theories. One reason was that formal-axiomatic theories allowed mathematical economists to improve the conceptual and theoretical foundations of economics and thereby to increase its scientific status. Furthermore, the separation between mathematical economics and other behavioral sciences was not as clear-cut as often argued. While economists did not modify their behavioral assumptions, some acknowledged the empirical shortcomings of their models. The paper reveals the multifaceted nature of rational choice theories reflected in the changing interpretations and roles of the theories in those early years.  相似文献   
50.
In this paper we estimate the willingness topay for a wolf management plan and a wolfdamage plan in Minnesota using the contingentvaluation method. The theoretical definition ofwillingness to pay for wolf protection iscomposed of use and non-use values. Weincorporate a don't know response option in thedichotomous choice valuation questions. A largenumber of respondents answered don't know. Themultinomial logit model is used todifferentiate between don't know and noresponses. Non-use motives are importantfactors that explain willingness to pay. We usethese benefit estimates in combination with twoalternative cost estimates to consider theefficiency of the wolf management and damageplans. Both plans have estimated benefitsgreater than costs.  相似文献   
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