2,856 research outputs found

    The Interaction between Nicotine and Negative Symptoms in Schizophrenia and Bipolar Disorder

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    Individuals with psychiatric conditions, such as schizophrenia (SZ) and bipolar disorders (BD), have a higher rate of smoking and have lower quit rates compared to the general population. As a dopamine agonist, nicotine may help alleviate negative symptoms by increasing abnormally low levels of dopamine in the prefrontal cortex and mesolimbic system consistent with the dopamine deficit hypothesis The purpose of the study is to further explore the interactions of nicotine and negative symptoms in a diverse population of individuals with serious mental illness. Furthermore, research examining interactions of nicotine and negative symptoms for individuals with schizophrenia compared to individuals with bipolar disorder who experience psychotic symptoms has not been conducted to our knowledge Consistent with the continuum of psychosis conceptualizations, the current study will examine rates of smoking in SZ and BP with psychotic features in order to provide additional information about shared symptoms and liabilities that may link schizophrenia and bipolar disorders. Hypothesis Based on the mechanism of nicotine, the current study expected higher rates of nicotine usage in groups experiencing negative symptoms as measured by the the Scale for the Negative Symptoms (SANS). Specifically, we expect SZ and BDP to have similar behavioral patterns on our assessments and nicotine usage due to the similarity of their symptomatic features. In contrast, we expect BDN to have a lower rate of nicotine usage due to its lower level of negative symptoms compared to SZ and BDP

    Differences in Ethnic and Sport Culture Salience Among College Students Participating in NCAA and Recreational Sports

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    This study aims to (1) examine differences between Ethnic Majority (European American) and Ethnic Minority (African American, Latina/o, Asian/Asian American, Pacific Islander, and Other) student athletes’ ratings of importance of their Ethnic Culture, (2) examine differences in the importance of Sport Culture among NCAA and Recreational (i.e., Club and Intramural) student athletes, and (3) determine if Ethnic Identification and Athlete Type interact to predict the importance of Ethnic Culture and Sport Culture. Student athletes were asked to fill out a demographic questionnaire, and then rate the importance of several cultural domains (i.e. Ethnic Culture and Sport Culture) using a novel measure, the Cultural Domain Menu (CDM). After a descriptive analysis was performed, Analysis of Variances (ANOVA) and several t-tests were conducted to test differences among Ethnic Majority and Ethnic Minority student athletes in the importance of their Ethnic and Sport Cultures. Findings demonstrated a significant difference between Ethnic Majority and Ethnic Minority student athletes’ ratings of the importance of their Ethnic Culture: Ethnic Majority ratings were found to be lower compared to Ethnic Minority student athletes. Results also showed a significant difference between NCAA and Recreational student athletes in their ratings of their Sport Culture: NCAA student athletes were found to rank their Sport Culture as more salient. Implications, limitations, and future directions for this study are discussed in regard to the results. These results serve as a great indicator of the mental health issues of importance when aiming to serve student athletes from different backgrounds

    Quantum Spinodal Decomposition

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    We study the process of spinodal decomposition in a scalar quantum field theory that is quenched from an equilibrium disordered initial state at Ti>TfT_i > T_f to a final state at Tf0T_f \approx 0. The process of formation and growth of correlated domains is studied in a Hartree approximation. We find an approximate scaling law for the size of the domains ξD(t)tξ0\xi_D(t) \approx \sqrt{t \xi_0} at long times for weakly coupled theories, with ξ0\xi_0 the zero temperature correlation length.Comment: REVTEX 13 pages(2 figures not included),PITT 93-0

    Repeated stimulation of the HPA axis alters white blood cell count without increasing oxidative stress or inflammatory cytokines in fasting elephant seal pups

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    The hypothalamic-pituitary-adrenal (HPA) axis controls the release of glucocorticoids, which regulate immune and inflammatory function by modulating cytokines, white blood cells and oxidative stress via glucocorticoid receptor (GR) signaling. Although the response to HPA activation is well characterized in many species, little is known about the impacts of HPA activation during extreme physiological conditions. Hence, we challenged 18 simultaneously fasting and developing elephant seal pups with daily intramuscular injections of adrenocorticotropin (ACTH), a GR antagonist (RU486), or a combination of the two (ACTH+RU486) for 4 days. We collected blood at baseline, 2 h and 4 days after the beginning of treatment. ACTH and ACTH+RU486 elevated serum aldosterone and cortisol at 2 h, with effects diminishing at 4 days. RU486 alone induced a compensatory increase in aldosterone, but not cortisol, at 4 days. ACTH decreased neutrophils at 2 h, while decreasing lymphocytes and increasing the neutrophil:lymphocyte ratio at 4 days. These effects were abolished by RU486. Despite alterations in white blood cells, there was no effect of ACTH or RU486 on transforming growth factor-β or interleukin-6 levels; however, both cytokines decreased with the 4 day fasting progression. Similarly, ACTH did not impact protein oxidation, lipid peroxidation or antioxidant enzymes, but plasma isoprostanes and catalase activity decreased while glutathione peroxidase increased with fasting progression. These data demonstrate differential acute (2 h) and chronic (4 days) modulatory effects of HPA activation on white blood cells and that the chronic effect is mediated, at least in part, by GR. These results also underscore elephant seals\u27 extraordinary resistance to oxidative stress derived from repeated HPA activation

    Quantifying structural damage from self-irradiation in a plutonium superconductor

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    The 18.5 K superconductor PuCoGa5 has many unusual properties, including those due to damage induced by self-irradiation. The superconducting transition temperature decreases sharply with time, suggesting a radiation-induced Frenkel defect concentration much larger than predicted by current radiation damage theories. Extended x-ray absorption fine-structure measurements demonstrate that while the local crystal structure in fresh material is well ordered, aged material is disordered much more strongly than expected from simple defects, consistent with strong disorder throughout the damage cascade region. These data highlight the potential impact of local lattice distortions relative to defects on the properties of irradiated materials and underscore the need for more atomic-resolution structural comparisons between radiation damage experiments and theory.Comment: 7 pages, 5 figures, to be published in PR

    High prevalence of <i>Rickettsia africae</i> variants in <i>Amblyomma variegatum</i> ticks from domestic mammals in rural western Kenya: implications for human health

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    Tick-borne spotted fever group (SFG) rickettsioses are emerging human diseases caused by obligate intracellular Gram-negative bacteria of the genus Rickettsia. Despite being important causes of systemic febrile illnesses in travelers returning from sub-Saharan Africa, little is known about the reservoir hosts of these pathogens. We conducted surveys for rickettsiae in domestic animals and ticks in a rural setting in western Kenya. Of the 100 serum specimens tested from each species of domestic ruminant 43% of goats, 23% of sheep, and 1% of cattle had immunoglobulin G (IgG) antibodies to the SFG rickettsiae. None of these sera were positive for IgG against typhus group rickettsiae. We detected Rickettsia africae–genotype DNA in 92.6% of adult Amblyomma variegatum ticks collected from domestic ruminants, but found no evidence of the pathogen in blood specimens from cattle, goats, or sheep. Sequencing of a subset of 21 rickettsia-positive ticks revealed R. africae variants in 95.2% (20/21) of ticks tested. Our findings show a high prevalence of R. africae variants in A. variegatum ticks in western Kenya, which may represent a low disease risk for humans. This may provide a possible explanation for the lack of African tick-bite fever cases among febrile patients in Kenya

    Planar Rotary Piezoelectric Motor Using Ultrasonic Horns

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    A motor involves a simple design that can be embedded into a plate structure by incorporating ultrasonic horn actuators into the plate. The piezoelectric material that is integrated into the horns is pre-stressed with flexures. Piezoelectric actuators are attractive for their ability to generate precision high strokes, torques, and forces while operating under relatively harsh conditions (temperatures at single-digit K to as high as 1,273 K). Electromagnetic motors (EM) typically have high rotational speed and low torque. In order to produce a useful torque, these motors are geared down to reduce the speed and increase the torque. This gearing adds mass and reduces the efficiency of the EM. Piezoelectric motors can be designed with high torques and lower speeds directly without the need for gears. Designs were developed for producing rotary motion based on the Barth concept of an ultrasonic horn driving a rotor. This idea was extended to a linear motor design by having the horns drive a slider. The unique feature of these motors is that they can be designed in a monolithic planar structure. The design is a unidirectional motor, which is driven by eight horn actuators, that rotates in the clockwise direction. There are two sets of flexures. The flexures around the piezoelectric material are pre-stress flexures and they pre-load the piezoelectric disks to maintain their being operated under compression when electric field is applied. The other set of flexures is a mounting flexure that attaches to the horn at the nodal point and can be designed to generate a normal force between the horn tip and the rotor so that to first order it operates independently and compensates for the wear between the horn and the rotor

    A First-Quantized Formalism for Cosmological Particle Production

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    We show that the amount of particle production in an arbitrary cosmological background can be determined using only the late-time positive-frequency modes. We don't refer to modes at early times, so there is no need for a Bogolubov transformation. We also show that particle production can be extracted from the Feynman propagator in an auxiliary spacetime. This provides a first-quantized formalism for computing particle production which, unlike conventional Bogolubov transformations, may be amenable to a string-theoretic generalization.Comment: 18 pages, LaTeX; v2: significantly revised for clarity; conclusions unchange
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