Objective
Brain–computer interfaces (BCIs) could potentially be used to interact with pathological brain signals to intervene and ameliorate their effects in disease states. Here, we provide ...proof‐of‐principle of this approach by using a BCI to interpret pathological brain activity in patients with advanced Parkinson disease (PD) and to use this feedback to control when therapeutic deep brain stimulation (DBS) is delivered. Our goal was to demonstrate that by personalizing and optimizing stimulation in real time, we could improve on both the efficacy and efficiency of conventional continuous DBS.
Methods
We tested BCI‐controlled adaptive DBS (aDBS) of the subthalamic nucleus in 8 PD patients. Feedback was provided by processing of the local field potentials recorded directly from the stimulation electrodes. The results were compared to no stimulation, conventional continuous stimulation (cDBS), and random intermittent stimulation. Both unblinded and blinded clinical assessments of motor effect were performed using the Unified Parkinson's Disease Rating Scale.
Results
Motor scores improved by 66% (unblinded) and 50% (blinded) during aDBS, which were 29% (p = 0.03) and 27% (p = 0.005) better than cDBS, respectively. These improvements were achieved with a 56% reduction in stimulation time compared to cDBS, and a corresponding reduction in energy requirements (p < 0.001). aDBS was also more effective than no stimulation and random intermittent stimulation.
Interpretation
BCI‐controlled DBS is tractable and can be more efficient and efficacious than conventional continuous neuromodulation for PD. Ann Neurol 2013;74:449–457
Research summary
We examine the correlations between financial resource allocation flow between business segments and two measures of overall firm financial performance using a sample of Compustat ...firms. Our analysis finds a consistent inverted U‐shape (or alternatively, V‐shape) relationship between those measures and firm profitability. Interestingly, nearly all the data lie on the upward sloping part of the curve. Taken together, these results support the notion that flows of financial capital are most often positively correlated with financial performance.
Managerial summary
A key question for any organization is how reallocating capital across business units is related to overall firm performance. We examine the correlations of firm profitability with a measure of change in year‐to‐year allocations across business units in a data set of several thousand firms spanning 18 years. Except in cases of the most extreme reallocations, our measure of firm reallocation is positively correlated with firm performance. Because we cannot prove causality, we cautiously conclude that our findings are consistent with a story that, in most cases, firms would benefit from greater internal reallocation of capital. The managerial question then becomes “what dynamic capabilities are necessary to increase the flow of resources across business segments?” Policies aimed at increasing allocation flow are likely to be beneficial.
Shift work is characterized by employees working outside the standard hours of 7:00 am to 6:00 pm. Because shift work includes night work, the normal sleep-wake cycle (circadian rhythm) is disrupted, ...with potential consequences for shift workers' physical and mental health.
To assess the pooled effects of shift work on mental health and to evaluate whether these differ in men and women.
We searched PubMed, Scopus, and Web of Science databases for peer-reviewed or government reports published up to August 2018
To be included, studies had to be longitudinal or case-control studies of shift work exposure associated with adverse mental health outcomes. For subanalyses, we grouped these outcomes as anxiety symptoms, depressive symptoms, or general poor mental health symptoms.
We followed the Meta-Analysis of Observational Studies in Epidemiology Group guidelines. We extracted adjusted risk estimates for each study to calculate pooled effect sizes (ESs) using random effect models and metaregression analysis to explore sources of heterogeneity.
We included 7 longitudinal studies, with 28 431 unique participants. Shift work was associated with increased overall risk of adverse mental health outcomes combined (ES = 1.28; 95% confidence interval CI = 1.02, 1.62;
= 70.6%) and specifically for depressive symptoms (ES = 1.33; 95% CI = 1.02, 1.74;
= 31.5%). Gender differences explained more than 90% of heterogeneity, with female shift workers more likely to experience depressive symptoms than female non-shift workers (odds ratio = 1.73; 95% CI = 1.39, 2.14).
To our knowledge, this is the first meta-analysis to investigate the pooled effects of shift work on the risk of poor mental health, including subanalyses by type of poor mental health and gender. Shift workers, particularly women, are at increased risk for poor mental health, particularly depressive symptoms.
Depression accounts for 4.3% of the global burden of disease and incidence, with mental disorders worldwide predicted to cost US $16.3 million by 2030. With 1 in 5 people in the United States and Europe doing shift work, and the increased risk of poor mental health among shift workers, shift work industries are a priority context for reducing this burden. Workplace health promotion programs and policies are needed to minimize shift workers' risk of poor mental health.
Why do individuals volunteer their time even when recipients receive far less value than the donor’s opportunity cost? Previous models of altruism that focus on the overall impact of a gift cannot ...rationalize this behavior, despite its prevalence. We develop a model that allows for differential warm glow depending on the form of the donation. In a series of laboratory experiments that control for other aspects of volunteering, such as its signaling value, subjects demonstrate behavior consistent with the theoretical assumption that gifts of time produce greater utility than the same transfers in the form of money. Subjects perform an effort task, accruing earnings at potentially different wage rates for themselves or a charity of their choice, with the ability to transfer any of their personal earnings to charity at the end of the experiment. Subjects exhibit strong preferences for donating time even when differential wage rates make it costly to do so. The results provide new insights on the nature of volunteering and gift giving.
Data, the online appendix, and the experimental instructions are available at
https://doi.org/10.1287/mnsc.2017.2951
.
This paper was accepted by Teck-Hua Ho, behavioral economics.
A Lagrangian/Eulerian simulation technique for an argon/helium plasma spray including 10–100 micron metal particles has been developed and characterized for manufacturing applications including a ...unique equilibrium-based approach to the argon ionization problem. Six metals were studied for behavior under a characteristic flow condition to assess the sensitivity of model predictions for application purposes. Particular attention was paid to the thermal properties of the six candidate metals, and a number of uncertainties of varying significance were found in surveying existing source materials for the properties. Methods for determining injection boundary conditions based on measured nozzle parameters are exhibited. Spray dynamics have been affiliated with model properties, which may help guide the exercise of identifying optimal spray conditions for new applications. Particle-mean velocity and temperatures are compared to experimentally obtained data, suggesting the model provides a reasonable approximation of the nozzle dynamics at a low power setting. A number of uncertainties in the modeling characteristics of the nozzle are evaluated through a parametric evaluation. The exercise highlights the importance of input and boundary conditions to the accuracy of the resultant spray.
The partnership dissolution literature has almost entirely focused on the properties of exit mechanisms in isolation taking other features of the break-up process as given. We consider a simple, ...two-stage model of the dissolution process where both the decision to dissolve and the roles the partners play in the exit mechanism are endogenously determined according to a “triggering rule.” We find certain pairings of triggering rules and exit mechanisms can lead to a war of attrition which inefficiently prolongs the dissolution process. However, since these theoretical predictions require sophisticated reasoning and backward induction, it is unclear whether the theory has any empirical validity. We therefore conduct a laboratory experiment to explore this question. Treatments are selected to test the main predictions of the model using combinations of exit mechanisms and triggering rules commonly seen in practice. The experimental results are largely supportive of the underlying theoretical predictions.
The aims of this study were to (i) examine gender differences in physical inactivity in countries with different levels of Human Development Index (HDI); and (ii) assess whether small changes in the ...prevalence of inactivity in women could achieve the World Health Organization's (WHO) global inactivity target.
Data on inactivity were extracted for 142 countries for the year 2010 from the WHO Data Repository. Data for HDI were obtained for the year 2010 from the United Nations Development Program. Absolute and relative gender differences were calculated for countries according to four HDI categories. The potential effects of increasing women's activity levels on achievement of the WHO physical inactivity target were computed.
Overall inactivity prevalence was higher in women (27%) than in men (20%). Women were more inactive than men in all except eight countries. Absolute gender differences median 7.5% (range -10.1 to 33.2) did not vary by HDI category, but there was a small negative correlation between relative gender difference in inactivity and HDI (rho -0.19; p = 0.02), which was mostly influenced by three outlier countries with low HDI. A decrease in inactivity levels of 4.8% points among women across the world would achieve the WHO target of reducing global levels of inactivity by 10%.
Gender differences in the prevalence of physical inactivity were highly variable, both within and across categories of HDI. Interventions which result in small changes in inactivity prevalence in women would achieve the 2025 WHO global target for inactivity, without any change to the prevalence in men.
Using an existing coordination (traffic) experiment, we investigate information's effect on traffic congestion when subjects already have a history of past play. In contrast to previous studies, our ...interventions neither alter aggregate nor individual payoffs. A second study isolates individual‐subject response to information using a fixed distribution of past subjects. We find information alters subject play: subjects switch roads more often and receive higher payoffs conditional on switching roads. Because switching reduces payoffs unconditionally, information does not generally improve payoffs overall. Only subjects that receive information upon starting the game appear to increase their payoffs due to the information treatment.
PDF
