6,174 research outputs found
Empathic Neural Responses Predict Group Allegiance.
Watching another person in pain activates brain areas involved in the sensation of our own pain. Importantly, this neural mirroring is not constant; rather, it is modulated by our beliefs about their intentions, circumstances, and group allegiances. We investigated if the neural empathic response is modulated by minimally-differentiating information (e.g., a simple text label indicating another's religious belief), and if neural activity changes predict ingroups and outgroups across independent paradigms. We found that the empathic response was larger when participants viewed a painful event occurring to a hand labeled with their own religion (ingroup) than to a hand labeled with a different religion (outgroup). Counterintuitively, the magnitude of this bias correlated positively with the magnitude of participants' self-reported empathy. A multivariate classifier, using mean activity in empathy-related brain regions as features, discriminated ingroup from outgroup with 72% accuracy; the classifier's confidence correlated with belief certainty. This classifier generalized successfully to validation experiments in which the ingroup condition was based on an arbitrary group assignment. Empathy networks thus allow for the classification of long-held, newly-modified and arbitrarily-formed ingroups and outgroups. This is the first report of a single machine learning model on neural activation that generalizes to multiple representations of ingroup and outgroup. The current findings may prove useful as an objective diagnostic tool to measure the magnitude of one's group affiliations, and the effectiveness of interventions to reduce ingroup biases
Heat-load simulator for heat sink design
Heat-load simulator is fabricated from 1/4-inch aluminum plate with a contact surface equal in dimensions and configuration to those of the electronic installation. The method controls thermal output to simulate actual electronic component thermal output
Ring cusp/hollow cathode discharge chamber performance studies
An experimental study was performed to determine the effects of hollow cathode position, anode position, and ring cusp magnetic field configuration and strength on discharge chamber performance. The results are presented in terms of comparative plasma ion energy cost, extracted ion fraction, and beam profile data. Such comparisons are used to demonstrate whether changes in performance are caused by changes in the loss rate of primary electrons to the anode or the loss rate of ions to discharge chamber walls or cathode and anode surfaces. Results show: (1) the rate of primary electron loss to the anode decreases as the anode is moved downstream of the ring cusp toward the screen grid; (2) the loss rate of ions to hollow cathode surfaces are excessive if the cathode is located upstream of a point of peak magnetic flux density at the discharge chamber centerline; and (3) the fraction of the ions produced that are lost to discharge chamber walls and ring magnet surfaces is reduced by positioning of the magnet rings so the plasma density is uniform over the grid surface, and adjusting their strength to a level where it is sufficient to prevent excessive ion losses by Bohm diffusion
Increased Metabolic Rate in X-linked Hypophosphatemic Mice
Hyp mice are a model for human X-linked hypophosphatemia, the most common form of vitamin D-resistant rickets. It has previously been observed that Hyp mice have a greater food consumption per gram body weight than do normal mice. This led to the search for some alteration in metabolism in Hyp mice. We found that oxygen consumption was significantly higher in Hyp mice than in normal C57BL/6J mice and this was accompanied by an increased percentage of cardiac output being delivered to organs of heat production (liver and skeletal muscle), to the skin, and to bone and a decreased percentage to the gastrointestinal tract of Hyp mice. The increased oxygen consumption in Hyp mice was not associated with increased plasma free T4 levels and was not affected by alterations in plasma phosphate produced by a low phosphate diet. The cause of the increased oxygen consumption is not known, and the role that this change and reported changes in distribution of cardiac output may play in the development of X-linked hypophosphatemia is also unknown. Study of the cardiovascular and thermoregulatory systems in Hyp mice should help increase understanding of the underlying mechanisms of this disease
Cyclic Ovarian Hormone Modulation of Supraspinal Δ\u3csup\u3e9\u3c/sup\u3e-tetrahydrocannabinol-induced Antinociception and Cannabinoid Receptor Binding in the Female Rat
Estrous cycle-related fluctuations in delta-9-tetrahydrocannabinol (THC)-induced antinociception have been observed in the rat. The aim of this study was to determine which major ovarian hormone modulates the antinociceptive effects of i.c.v. THC, and whether hormone modulation of THC\u27s behavioral effects could be due to changes in brain cannabinoid receptors (CBr). Vehicle (oil) or hormones (estradiol or progesterone, or both) were administered to female rats on days 3 and 7 post-ovariectomy. On the morning or afternoon of day 8 or day 9, vehicle or THC (100 μg) was administered i.c.v. Paw pressure, tail withdrawal, locomotor activity and catalepsy tests were conducted over a 3-h period. Estradiol (with and without progesterone) enhanced THC-induced paw pressure antinociception only. Ovarian hormones time-dependently modulated CBr in brain structures that mediate antinociception and locomotor activity, but the changes observed in CBr did not parallel changes in behavior. However, the time course of CBr changes must be further elucidated to determine the functional relationship between receptor changes and antinociceptive sensitivity to THC
Trends and correlates of marijuana use among late middle-aged and older adults in the United States, 2002–2014
BACKGROUND: Recent trend studies suggest that marijuana use is on the rise among the general population of adults ages 18 and older in the United States. However, little is known about the trends in marijuana use and marijuana-specific risk/protective factors among American adults during the latter part of adulthood.
METHOD: Findings are based on repeated, cross-sectional data collected from late middle-aged (ages 50–64) and older adults (ages 65 and older) surveyed as part of the National Survey on Drug Use and Health between 2002 and 2014.
RESULTS: The prevalence of past-year marijuana use among late middle-aged adults increased significantly from a low of 2.95% in 2003 to a high of 9.08% in 2014. Similarly, the prevalence of marijuana use increased significantly among older adults from a low of 0.15% in 2003 to a high of 2.04% in 2014. Notably, the upward trends in marijuana use remained significant even when accounting for sociodemographic, substance use, behavioral, and health-related factors. We also found that decreases in marijuana-specific protective factors were associated with the observed trend changes in marijuana use among late middle-aged and older adults, and observed a weakening of the association between late-middle aged marijuana use and risk propensity, other illicit drug use, and criminal justice system involvement over the course of the study.
CONCLUSIONS: Findings from the present study provide robust evidence indicating that marijuana use among older Americans has increased markedly in recent years, with the most evident changes observed between 2008 and 2014
Current flow in a plasma caused by dielectric breakdown
Spacecraft with a thin dielectric coating on the outer surface of the structure which are biased (-200 V) negative relative to the atmospheric plasma are susceptible to dielectric breakdown. This paper will present experimental tests designed to measure the electron current flow from the structure through the plasma during the arc. The current path was examined in three parts: the electrons supplied through the structure and the arc to the outer structure, the expansion of the arc into the ambient plasma, and the return current through the ambient plasma. The measured electron current either flowing from the plasma or supplied to the plasma by the arc in each case was compared to the random thermal electron current which could be collected. The results of the tests show a spacecraft is capable of supporting arcs with peak currents greater than thermal electron currents, and these currents will be dependent upon the amount of stored charge in the structure (i.e., the structure's surface area and dielectric thickness). Also, the results of these tests show that it is possible for structures with a self capacitance of 10 microFarads to see peak currents of 90 A and structures with 1000 microFarads (i.e., capacitance of one Space Station Freedom module) to produce peak currents of 1000 A
The Effects of Gender and Race on Physician Treatment of Patient Emotion.
This study established theoretical and empirical foundations for the investigation into how physicians deal with (treat) patient emotion. The questions posed, Do physicians employ specific strategies to treat patient emotion? and What are the effects of physician-patient social characteristics (gender and race) on emotion treatment? Coalescing two seemingly incongruent perspectives (social constructionism and Kemper\u27s social relational theory), I clarified the conceptual basis for the emotion management of other people. From these perspectives, I developed a three stage theory to describe and explain the physician treatment of patient emotion (triaging, diagnosing, and treatment), as well as appreciate the effects of social characteristics on this process. Regarding the first research question, survey data collected from 225 practicing physicians supported the twenty-two proposed strategies to treat patient emotion. Considering the second question, analyses produced some support for the predicted effects of gender and race. For physician gender, female physicians were, in general, more likely to treat patient emotion than their male colleagues. However, physician gender was only significant when the physicians\u27 type of medical practice (general vs. specialized) and practice setting (private vs. institutional) were controlled in the analysis model, suggesting that physician gender differences were more complex than those based exclusively on sex. For patient gender and race, analysis indicated that physicians randomly assigned black patient vignettes had significantly higher scores on measures of emotion evading and lower scores for emotion importance than physicians with white patients. This suggests that a patient\u27s social characteristics do influence physician treatment of patient emotion. Overall, my research demonstrates a growing ideological acceptance and consideration for the role of emotion in medicine, whether this is occurring in actual practice remains unknown
Do Complexity Measures of Frontal EEG Distinguish Loss of Consciousness in Geriatric Patients Under Anesthesia?
While geriatric patients have a high likelihood of requiring anesthesia, they carry an increased risk for adverse cognitive outcomes from its use. Previous work suggests this could be mitigated by better intraoperative monitoring using indexes defined by several processed electroencephalogram (EEG) measures. Unfortunately, inconsistencies between patients and anesthetic agents in current analysis techniques have limited the adoption of EEG as standard of care. In attempts to identify new analyses that discriminate clinically-relevant anesthesia timepoints, we tested 1/f frequency scaling as well as measures of complexity from nonlinear dynamics. Specifically, we tested whether analyses that characterize time-delayed embeddings, correlation dimension (CD), phase-space geometric analysis, and multiscale entropy (MSE) capture loss-of-consciousness changes in EEG activity. We performed these analyses on EEG activity collected from a traditionally hard-to-monitor patient population: geriatric patients on beta-adrenergic blockade who were anesthetized using a combination of fentanyl and propofol. We compared these analyses to traditional frequency-derived measures to test how well they discriminated EEG states before and after loss of response to verbal stimuli. We found spectral changes similar to those reported previously during loss of response. We also found significant changes in 1/f frequency scaling. Additionally, we found that our phase-space geometric characterization of time-delayed embeddings showed significant differences before and after loss of response, as did measures of MSE. Our results suggest that our new spectral and complexity measures are capable of capturing subtle differences in EEG activity with anesthesia administration-differences which future work may reveal to improve geriatric patient monitoring
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