8,007 research outputs found

    A Survey Of Drug Abuse In A Selected Junior High School

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    INTRODUCTION Over the past several years, public concern has greatly increased over mind-altering drug use among students. That concern has been evoked by a flow of reports from individuals, mass media, the police, and other governmental agencies, educators, and the community. The reports are consistent in telling of a remarkable expansion of student interest in and use of drugs which are illicit or exotic. Drug abuse is an issue that concerns all levels of society, from the very low socio-economic groups to the extreme high socio-economic groups. The potential drug abusers range from the submissive poor to the successful affluent groups of individuals. The problem of drug abuse in our nation is rising at such an alarming rate, which warrants the condition that if we are to survive as a society that is not hampered by the frills and thrills of addicts, it is imperative that we find a workable solution. Currently, preventative and rehabilitative efforts are being made to combat the problem of drug abuse. There are controversial views as to the cause of drug abuse, which consequently make drug abuse a difficult problem for rehabilitation. Rehabilitation or the road back (as it is often called) is a puzzling task. A recent review of rehabilitation approaches to drug abuse stated: No one knows whether the goals of treatment as set forth are realistic or even desirable. Since no one knows why people become narcotic addicts, no one knows either how to make them stop or what will happen if they do stop. Not all approaches to rehabilitation are the same; different people require somewhat different treatment. The method of treatment are unlike in nature as the individuals themselves. The task of getting people to stop abusing drugs is as complex as it is confusing. According to DeLong, there is no uniform theory of addiction and no adequate description of the addict population. Also, addiction has spread rapidly in recent years, and we know less about the new population than we do about the old, and we knew very little before

    Spin Structure of Many-Body Systems with Two-Body Random Interactions

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    We investigate the spin structure of many-fermion systems with a spin-conserving two-body random interaction. We find a strong dominance of spin-0 ground states and considerable correlations between energies and wave functions of low-lying states with different spin, but no indication of pairing. The spectral densities exhibit spin-dependent shapes and widths, and depend on the relative strengths of the spin-0 and spin-1 couplings in the two-body random matrix. The spin structure of low-lying states can largely be explained analytically.Comment: 10 pages, including 3 figure

    Perceptions of Clinical Research Participation among African American Women

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    Background: Recruiting minority women into clinical research remains a significant challenge to conducting ethnically representative research. The main objective of this Office on Women's Health, DHHS-funded e-health database evaluation project was to examine African American women 's thoughts and perceptions about the clinical research process and about participation in the University of Michigan Women's Health Registry research database. Methods: Thirty-one African American women were recruited from the community to participate in a total of five 90-minute focus group discussions. All sessions were audiotaped and transcribed verbatim. Thematic content analysis was used to identify relevant themes about participation in clinical research and the Women's Health Registry. Results: Ten common trends were identified. (1) Information about the Women's Health Registry is not reaching the community. (2) Research is perceived as biased to benefit Caucasians. (3) Community involvement by the research team is critical for trust to develop. (4) Research directly relevant to African Americans or their community will encourage participation. (5) Researchers should use existing networks and advertise in appropriate locations. (6) The community needs more information concerning research. (7) Compensation is important. (8) Research that addresses a personal or family medical problem encourages involvement. (9) Minority representation on the research team is a motivator to participation. (10) There is limited time for healthcare-related activities. Conclusions: Successful recruitment strategies for African American women should feature community-based, culturally appropriate approaches. Online research databases for subject recruitment will likely be successful only if implemented within a broader community-oriented program.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63122/1/jwh.2006.0124.pd

    Wave Function Structure in Two-Body Random Matrix Ensembles

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    We study the structure of eigenstates in two-body interaction random matrix ensembles and find significant deviations from random matrix theory expectations. The deviations are most prominent in the tails of the spectral density and indicate localization of the eigenstates in Fock space. Using ideas related to scar theory we derive an analytical formula that relates fluctuations in wave function intensities to fluctuations of the two-body interaction matrix elements. Numerical results for many-body fermion systems agree well with the theoretical predictions.Comment: 4 pages, 2 figure

    How does reviewing the evidence change veterinary surgeons' beliefs regarding the treatment of ovine footrot? A quantitative and qualitative study

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    Footrot is a widespread, infectious cause of lameness in sheep, with major economic and welfare costs. The aims of this research were: (i) to quantify how veterinary surgeons’ beliefs regarding the efficacy of two treatments for footrot changed following a review of the evidence (ii) to obtain a consensus opinion following group discussions (iii) to capture complementary qualitative data to place their beliefs within a broader clinical context. Grounded in a Bayesian statistical framework, probabilistic elicitation (roulette method) was used to quantify the beliefs of eleven veterinary surgeons during two one-day workshops. There was considerable heterogeneity in veterinary surgeons’ beliefs before they listened to a review of the evidence. After hearing the evidence, seven participants quantifiably changed their beliefs. In particular, two participants who initially believed that foot trimming with topical oxytetracycline was the better treatment, changed to entirely favour systemic and topical oxytetracycline instead. The results suggest that a substantial amount of the variation in beliefs related to differences in veterinary surgeons’ knowledge of the evidence. Although considerable differences in opinion still remained after the evidence review, with several participants having non-overlapping 95% credible intervals, both groups did achieve a consensus opinion. Two key findings from the qualitative data were: (i) veterinary surgeons believed that farmers are unlikely to actively seek advice on lameness, suggesting a proactive veterinary approach is required (ii) more attention could be given to improving the way in which veterinary advice is delivered to farmers. In summary this study has: (i) demonstrated a practical method for probabilistically quantifying how veterinary surgeons’ beliefs change (ii) revealed that the evidence that currently exists is capable of changing veterinary opinion (iii) suggested that improved transfer of research knowledge into veterinary practice is needed (iv) identified some potential obstacles to the implementation of veterinary advice by farmers

    Spin Bottlenecks in the Quantum Hall Regim

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    We present a theory of time-dependent tunneling between a metal and a partially spin-polarized two-dimensional electron system (2DES). We find that the leakage current which flows to screen an electric field between the metal and the 2DES is the sum of two exponential contributions whose relative weights depend on spin-dependent tunneling conductances, on quantum corrections to the electrostatic capacitance of the tunnel junction, and on the rate at which the 2DES spin-polarization approaches equilibrium. For high-mobility and homogeneous 2DES's at Landau level filling factor ν=1\nu=1, we predict a ratio of the fast and slow leakage rates equal to (2K+1)2(2K+1)^2 where KK is the number of reversed spins in the skyrmionic elementary charged excitations.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let

    Genetic variation at CHRNA5-CHRNA3-CHRNB4 interacts with smoking status to influence body mass index

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    Cigarette smoking is associated with lower body mass index (BMI), and a commonly cited reason for unwillingness to quit smoking is a concern about weight gain. Common variation in the CHRNA5-CHRNA3-CHRNB4 gene region (chromosome 15q25) is robustly associated with smoking quantity in smokers, but its association with BMI is unknown. We hypothesized that genotype would accurately reflect smoking exposure and that, if smoking were causally related to weight, it would be associated with BMI in smokers, but not in never smokers

    Ground-State Magnetization for Interacting Fermions in a Disordered Potential : Kinetic Energy, Exchange Interaction and Off-Diagonal Fluctuations

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    We study a model of interacting fermions in a disordered potential, which is assumed to generate uniformly fluctuating interaction matrix elements. We show that the ground state magnetization is systematically decreased by off-diagonal fluctuations of the interaction matrix elements. This effect is neglected in the Stoner picture of itinerant ferromagnetism in which the ground-state magnetization is simply determined by the balance between ferromagnetic exchange and kinetic energy, and increasing the interaction strength always favors ferromagnetism. The physical origin of the demagnetizing effect of interaction fluctuations is the larger number of final states available for interaction-induced scattering in the lower spin sectors of the Hilbert space. We analyze the energetic role played by these fluctuations in the limits of small and large interaction UU. In the small UU limit we do second-order perturbation theory and identify explicitly transitions which are allowed for minimal spin and forbidden for higher spin. These transitions then on average lower the energy of the minimal spin ground state with respect to higher spin. For large interactions UU we amplify on our earlier work [Ph. Jacquod and A.D. Stone, Phys. Rev. Lett. 84, 3938 (2000)] which showed that minimal spin is favored due to a larger broadening of the many-body density of states in the low-spin sectors. Numerical results are presented in both limits.Comment: 35 pages, 24 figures - final, shortened version, to appear in Physical Review

    Spin dependent scattering of a domain-wall of controlled size

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    Magnetoresistance measurements in the CPP geometry have been performed on single electrodeposited Co nanowires exchange biased on one side by a sputtered amorphous GdCo layer. This geometry allows the stabilization of a single domain wall in the Co wire, the thickness of which can be controlled by an external magnetic field. Comparing magnetization, resistivity, and magnetoresistance studies of single Co nanowires, of GdCo layers, and of the coupled system, gives evidence for an additional contribution to the magnetoresistance when the domain wall is compressed by a magnetic field. This contribution is interpreted as the spin dependent scattering within the domain wall when the wall thickness becomes smaller than the spin diffusion length.Comment: 9 pages, 13 figure

    Electronic and structural properties of vacancies on and below the GaP(110) surface

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    We have performed total-energy density-functional calculations using first-principles pseudopotentials to determine the atomic and electronic structure of neutral surface and subsurface vacancies at the GaP(110) surface. The cation as well as the anion surface vacancy show a pronounced inward relaxation of the three nearest neighbor atoms towards the vacancy while the surface point-group symmetry is maintained. For both types of vacancies we find a singly occupied level at mid gap. Subsurface vacancies below the second layer display essentially the same properties as bulk defects. Our results for vacancies in the second layer show features not observed for either surface or bulk vacancies: Large relaxations occur and both defects are unstable against the formation of antisite vacancy complexes. Simulating scanning tunneling microscope pictures of the different vacancies we find excellent agreement with experimental data for the surface vacancies and predict the signatures of subsurface vacancies.Comment: 10 pages, 6 figures, Submitted to Phys. Rev. B, Other related publications can be found at http://www.rz-berlin.mpg.de/th/paper.htm
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