Gender Differences in Current Received during Transcranial Electrical Stimulation.

Low current transcranial electrical stimulation (tCS) is an effective but somewhat inconsistent tool for augmenting neuromodulation. In this study, we used 3D MRI guided electrical transcranial stimulation modeling to estimate the range of current intensities received at cortical brain tissues. Combined T1, T2, and proton density MRIs from 24 adult subjects (12 male and 12 female) were modeled with virtual electrodes placed at F3, F4, C3, and C4. Two sizes of electrodes 20 mm round and 50 mm × 45 mm were examined at 0.5, 1, and 2 mA input currents. The intensity of current received was sampled in a 1-cm sphere placed at the cortex directly under each scalp electrode. There was a 10-fold difference in the amount of current received by individuals. A large gender difference was observed with female subjects receiving significantly less current at targeted parietal cortex than male subjects when stimulated at identical current levels (P < 0.05). Larger electrodes delivered somewhat larger amounts of current than the smaller ones (P < 0.01). Electrodes in the frontal regions delivered less current than those in the parietal region (P < 0.05). There were large individual differences in current levels that the subjects received. Analysis of the cranial bone showed that the gender difference and the frontal parietal differences are due to differences in cranial bone. Males have more cancelous parietal bone and females more dense parietal bone (P < 0.01). These differences should be considered when planning tCS studies and call into question earlier reports of gender differences due to hormonal influences

Slack And Crash Risk

We examine how a firm’s operational slack is associated with current income and future stock price crash risk. By doing so, we test the validity of a firm’s alternative motivations for holding operational slack. We show that Supply Chain Slack, which is based on excess working capital, is associated with higher current profits and higher future crash risk. This evidence is consistent with the firm hoarding bad news. In contrast, SG&A Slack, which is based on excess selling, general, and administrative expenses, is associated with lower current income and lower future crash risk. This evidence is consistent with the firm insuring against rare and adverse events. Furthermore, a firm’s stock price crash risk is lower when a slack type is more costly, consistent with both motivations. Overall, our findings suggest a stronger profit-crash risk tradeoff when firms hold more operational slack

Which Institutional Investors Trade Based on Private Information About Earnings and Returns?

Recent work suggests that institutional investors execute profitable trades based on private information about earnings and returns. We provide new evidence on the prevalence and sources of such informed trading by (1) testing for the creation and liquidation of positions based on private information, (2) introducing private information proxies that reflect the size and nature of an institution\u27s position in each portfolio firm, and (3) using a methodology that examines multiple investor characteristics simultaneously at the institution-firm level. We find that changes in ownership by institutions with large positions in a firm are consistent with informed trading. However, other previously documented proxies for private information produce results more consistent with risk-based trading (e.g., investment style) or insignificant in the presence of other proxies (e.g., fiduciary type). We also find that informed trading is more prevalent in small firms and when the large positions are taken by investment advisers and large institutions

Analyst Monitoring of Opportunistic Firm Behavior

Prior literature presents mixed evidence about analyst monitoring of opportunistic firm behavior. We find that analysts reduce annual earnings forecasts as well as target prices around earnings announcements of the first three quarters of the fiscal year as if they punish a firm’s accrual-based and real earnings management during the quarters. The forecast reductions are more pronounced when analysts have less conflicts of interest with the firm (i.e., when analysts are employed by smaller brokers and when they are less experienced) and when analysts are less influential and less accurate. We also find that the firm responds to analyst monitoring by reversing its opportunistic behavior during the subsequent quarter. The reversals are more pronounced when the firm relies more on analyst optimism (i.e., when the firm has a lower market capitalization, higher market-to-book ratio and greater use of external financing). Collectively, our findings shed light on the dynamics of analyst monitoring by documenting sequential actions of analysts and the firm after the firm’s opportunistic behavior

Management Forecast Quality and Capital Investment Decisions

Corporate investment decisions require managers to forecast expected future cash flows from potential investments. Although these forecasts are a critical component of successful investing, they are not directly observable by external stakeholders. In this study, we investigate whether the quality of managers' externally reported earnings forecasts can be used to infer the quality of their corporate investment decisions. Relying on the intuition that managers draw on similar skills when generating external earnings forecasts and internal payoff forecasts for their investment decisions, we predict that managers with higher quality external earnings forecasts make better investment decisions. Consistent with our prediction, we find that forecasting quality is positively associated with the quality of both acquisition and capital expenditure decisions. Our evidence suggests that externally observed forecasting quality can be used to infer the quality of capital budgeting decisions within firms

Truthmakers and modality

This paper attempts to locate, within an actualist ontology, truthmakers for modal truths: truths of the form or . In section 1 I motivate the demand for substantial truthmakers for modal truths. In section 2 I criticise Armstrong’s account of truthmakers for modal truths. In section 3 I examine essentialism and defend an account of what makes essentialist attributions true, but I argue that this does not solve the problem of modal truth in general. In section 4 I discuss, and dismiss, a theistic account of the source of modal truth proposed by Alexander Pruss. In section 5 I offer a means of (dis)solving the problem

Do Children\u27s Advocacy Centers improve families’ experiences of child sexual abuse investigations?

Abstract Objective The Children\u27s Advocacy Center (CAC) model of child abuse investigation is designed to be more child and family-friendly than traditional methods, but there have been no rigorous studies of their effect on children\u27s and caregivers’ experience. Data collected as part of the Multi-Site Evaluation of Children\u27s Advocacy Centers were used to examine whether CACs improve caregivers’ and children\u27s satisfaction with investigations. Methods Nonoffending caregiver and child satisfaction were assessed during research interviews, including the administration of a 14-item Investigation Satisfaction Scale (ISS) for caregivers. Two hundred and twenty-nine sexual abuse cases investigated through a CAC were compared to 55 cases investigated in communities with no CAC. Results Hierarchical linear regression results indicated that caregivers in CAC cases were more satisfied with the investigation than those from comparison sites, even after controlling for a number of relevant variables. There were few differences between CAC and comparison samples on children\u27s satisfaction. Children described moderate to high satisfaction with the investigation, while a minority expressed concerns about their experience. Conclusions The CAC model shows promise for improving families’ experiences, but to build upon this promise, agencies will need to systematize procedures for refining and adapting the model as new research becomes available

Analytic Diffraction Corrections to Ultrasonic Scattering Measurements

Ultrasonic theories generally predict a scattering amplitude which relates a spherically spreading, far-field scattered wave to an incident plane wave. In ultrasonic immersion measurements, the frequency and angular dependences of the scattering amplitude are convolved with those of the transmitting and receiving transducers and the propagation through the liquid-solid and solid-liquid interfaces. This paper presents a set of approximate corrections for these effects for the cases of angle beam inspection through planar, spherically curved or cylindrically curved surfaces. The primary parameters in the correction are the function D, which corrects for the diffraction effects occurring during a transducer calibration experiment, and the function C, which describes the on-axis pressure variation of the beam. Values of C and D are available in the literature for the case of a piston transducer radiating into an infinite fluid medium. The major portion of this paper is concerned with the extension of those results to the aforementioned two media problems in which mode conversion, refraction, diffraction, and focussing all play interrelated roles. Results of preliminary experiments to test the corrections are also included

Assessing the role of undetected colonization and isolation precautions in reducing Methicillin-Resistant Staphylococcus aureus transmission in intensive care units

<p>Abstract</p> <p>Background</p> <p>Screening and isolation are central components of hospital methicillin-resistant <it>Staphylococcus aureus </it>(MRSA) control policies. Their prevention of patient-to-patient spread depends on minimizing undetected and unisolated MRSA-positive patient days. Estimating these MRSA-positive patient days and the reduction in transmission due to isolation presents a major methodological challenge, but is essential for assessing both the value of existing control policies and the potential benefit of new rapid MRSA detection technologies. Recent methodological developments have made it possible to estimate these quantities using routine surveillance data.</p> <p>Methods</p> <p>Colonization data from admission and weekly nares cultures were collected from eight single-bed adult intensive care units (ICUs) over 17 months. Detected MRSA-positive patients were isolated using single rooms and barrier precautions. Data were analyzed using stochastic transmission models and model fitting was performed within a Bayesian framework using a Markov chain Monte Carlo algorithm, imputing unobserved MRSA carriage events.</p> <p>Results</p> <p>Models estimated the mean percent of colonized-patient-days attributed to undetected carriers as 14.1% (95% CI (11.7, 16.5)) averaged across ICUs. The percent of colonized-patient-days attributed to patients awaiting results averaged 7.8% (6.2, 9.2). Overall, the ratio of estimated transmission rates from unisolated MRSA-positive patients and those under barrier precautions was 1.34 (0.45, 3.97), but varied widely across ICUs.</p> <p>Conclusions</p> <p>Screening consistently detected >80% of colonized-patient-days. Estimates of the effectiveness of barrier precautions showed considerable uncertainty, but in all units except burns/general surgery and one cardiac surgery ICU, the best estimates were consistent with reductions in transmission associated with barrier precautions.</p