Approximate maximum likelihood estimation for stochastic differential equations with random effects in the drift and the diffusion

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.     

Scale and scope economies for drug abuse treatment costs: evidence for Washington State

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.     

Indigenous livelihoods, slash-and-burn agriculture, and carbon stocks in Eastern Panama

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.     

Registered nurses' perspectives on health care and the 2008 presidential election

As this historic presidential election draws near, what do RNs think of our nation's priorities? Which candidates do they think will be most effective in shaping our health care system and addressing the most pressing issues of our time? The results of this survey show that RNs do not identify overwhelmingly with one political ideology or party and, in fact, they closely resemble the public on these political dimensions. The data also show that RNs identify health care issues as the most important problem facing the nation. RNs who believe that it is the responsibility of the government to provide health insurance to those without it, have more confidence in the government to achieve this outcome, and are more likely to be Democrats than Republicans. The presidential election is expected to be highly contested and could be determined by a relatively small margin of votes and, thus, nurses should recognize their chances of influencing the outcome of the election. The data from this survey provide baseline information potentially useful to increasing the political influence of the nursing profession, informing other organizations about where they might align with nurses, and helping candidates and the political parties compete more effectively in seeking the support of roughly 3 million RN voters.     

The link between perceived HRM practices,performance and well‐being: the moderating effect of trust in the employer

The present study examines the interaction between perceived HRM practices and trust in the employer on employee performance and well‐being. Specifically, the study tests whether trust in the employer moderates the relationships between perceptions of HRM practices and task performance (as rated by employees’ supervisors), organisational citizenship behaviour, turnover intentions and employee well‐being. Support was found for the majority of the hypotheses using data from 613 employees and their line managers in a service sector organisation in the UK. Trust in the employer moderates the relationships between perceived HRM practices and task performance, turnover intentions and individual well‐being, but not organisational citizenship behaviour. Implications of the findings for organisations and future research are discussed.     

Does Having a Dysfunctional Personality Hurt Your Career? Axis II Personality Disorders and Labor Market Outcomes

Despite recent interest in how psychiatric disorders affect work outcomes, little is known about the role of personality disorders (PDs), which are poorly understood yet prevalent (15%) and impairing. We used nationally representative data for 12,457 men and 16,061 women to examine associations of PDs with any employment, full-time employment, chronic unemployment, being fired or laid off, and having trouble with a boss or co-worker. Antisocial, paranoid, and obsessive-compulsive PDs demonstrated the broadest patterns of associations with adverse outcomes. Findings suggest that PDs may have implications for the productivity of co-workers as well as that of the disordered employees themselves.     

Airport infrastructure spillovers in a network system

Airports in the US air transport network have become increasingly congested, leading to delays for business travelers and freight shipments. Since disruptions in one part of the network exacerbate problems throughout the system, airport infrastructure expansions to enhance air traffic flows confer travel-time savings and reliability benefits, and thus increased worker productivity and shipping efficiency for manufacturing firms. We evaluate such spillovers, and find that higher own-state airport infrastructure implies lower manufacturing costs from both labor- and materials-savings. Airport expansion in connected states has a comparable effect for states with hub airports, and an even greater impact for other states.     

Is More Information Always Better? An Experimental Study of Charitable Giving and Hurricane Katrina

We report results of an experiment designed to assess the impact of Hurricane Katrina on the pattern and level of charitable contributions of donors. The study includes an experimental measure of charitable giving and targets three charities: the American Red Cross, the Salvation Army, and Oxfam International. In the experiment subjects make allocation decisions from three endowments ($10, $20, and $50) and with four different matching subsidies (0%, 25%, 50%, and 100%), with the matching amount provided by the experimenter. Two locations (Texas and Minnesota) and two information conditions are used. Survey measures of sympathy, risk perceptions, and perceptions of Katrina victims are also collected. The probability and amount of giving are responsive to the experimental design parameters—the endowment and match. We find evidence of “Katrina overload” as those closest to the disaster respond negatively to Katrina-related priming information. Perceptions of the psychological attitudes of the victims of the disaster have a significant effect on the amount given.