291 research outputs found

    Duty to Warn and Intervention with HIV-Positive Clients

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    Complex ethical and legal issues are involved when an HIV-positive client presents a danger to others as a result of engaging in unprotected sex or needle sharing. This article presents a detailed assessment-and-intervention model that is based on the integration of ethical and legal principles with information about the level of risk associated with a client\u27s behavior, the HIV status of the client, and the sexual or needle-sharing partner\u27s awareness of the client\u27s HIV status. Appropriate interventions, including the duty to warn, are identified for each of the risk levels

    Detection, numerical simulation and approximate inversion of optoacoustic signals generated in multi-layered PVA hydrogel based tissue phantoms

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    In this article we characterize optoacoustic signals generated from layered tissue phantoms via short laser pulses by experimental and numerical means. In particular, we consider the case where scattering is effectively negligible and the absorbed energy density follows Beer-Lambert's law, i.e. is characterized by an exponential decay within the layers and discontinuities at interfaces. We complement experiments on samples with multiple layers, where the material properties are known a priori, with numerical calculations for a pointlike detector, tailored to suit our experimental setup. Experimentally, we characterize the acoustic signal observed by a piezoelectric detector in the acoustic far-field in backward mode and we discuss the implication of acoustic diffraction on our measurements. We further attempt an inversion of an OA signal in the far-field approximation.Comment: 10 pages, 6 figures, supplementary code at https://github.com/omelchert/SONOS.gi

    Testing Models of Counselor Development With a Measure of Counseling Self-Efficacy

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    Models of counselor development have become very popular, but empirical research has found differences primarily between beginning graduate students and doctoral interns, in the research described here, a counseling self-efficacy instrument was developed and was used to test hypotheses based on self-efficacy theory and models of counselor development, both of which would make similar predictions about increases in counseling self-efficacy resulting from clinical training and experience. The findings include strong reliability and validity evidence for the instrument and several significantly different groups of participants that correspond roughly to the groups hypothesized in stage models of counselor development

    Single And Double-electron Removal From H− In Energetic Collisions With Multiply-charged Argon Ions

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    Absolute cross-sections have been measured and compared to CTMC-calculations for single and double-electron removal from H− in collisions with Arq+ ions (q ≤ 8) at Ec.m. = 50 keV. The single-electron removal cross-sections are found to scale with q1.3, and for the H− + Ar4+ system, this cross-section is found to have a weak energy dependence from 3 keV to 100 keV. A major implication of our measurements is that plasma neutralizers based on multiply charged ions for high-efficiency conversion of intense H− beams into H0 gain little in expected reduced length due to the inapplicability of q2-scaling in the H− single-electron removal cross-section. © 1989, IOP Publishing Ltd

    Fractal dimension of domain walls in two-dimensional Ising spin glasses

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    We study domain walls in 2d Ising spin glasses in terms of a minimum-weight path problem. Using this approach, large systems can be treated exactly. Our focus is on the fractal dimension dfd_f of domain walls, which describes via \simL^{d_f} the growth of the average domain-wall length with %% systems size L×LL\times L. %% 20.07.07 OM %% Exploring systems up to L=320 we yield df=1.274(2)d_f=1.274(2) for the case of Gaussian disorder, i.e. a much higher accuracy compared to previous studies. For the case of bimodal disorder, where many equivalent domain walls exist due to the degeneracy of this model, we obtain a true lower bound df=1.095(2)d_f=1.095(2) and a (lower) estimate df=1.395(3)d_f=1.395(3) as upper bound. Furthermore, we study the distributions of the domain-wall lengths. Their scaling with system size can be described also only by the exponent dfd_f, i.e. the distributions are monofractal. Finally, we investigate the growth of the domain-wall width with system size (``roughness'') and find a linear behavior.Comment: 8 pages, 8 figures, submitted to Phys. Rev. B; v2: shortened versio

    Gemcitabine and carboplatin in intensively pretreated patients with metastatic breast cancer

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    Background: Patients with metastatic breast cancer (MBC) are increasingly exposed to anthracyclines and taxanes either during treatment of primary breast cancer or during initial therapy of metastatic disease. The combination of gemcitabine and carboplatin was therefore investigated as an anthracycline- and taxane-free treatment option. Patients and Methods: MBC patients previously treated with chemotherapy were enrolled in a multicenter phase II study. Treatment consisted of gemcitabine (1,000 mg/m(2) i.v. on days 1 and 8) and carboplatin (AUC 4 i.v. on day 1) applied every 3 weeks. Results: Thirty-nine patients were recruited, and a total of 207 treatment cycles were applied with a median of 5 cycles per patient. One complete response and 11 partial responses were observed for an overall response rate of 31% (95% CI: 17-48%). Twelve patients (31%) had stable disease. Median time to progression was 5.3 months (95% CI: 2.6-6.7 months) and median overall survival from start of treatment was 13.2 months (95% CI: 8.7-16.7 months). Grade 3/4 hematological toxicity included leukopenia (59%/5%), thrombo-cytopenia (26%/23%) and anemia (10%/0%). Nonhematological toxicity was rarely severe. Conclusion: Combination chemotherapy with gemcitabine and carboplatin is an effective and generally well-tolerated treatment option for intensively pretreated patients with MBC. Due to a considerable incidence of severe thrombocytopenia it would be reasonable to consider starting gemcitabine at the lower dose level of 800 mg/m(2). Copyright (c) 2008 S. Karger AG, Basel
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