1,718 research outputs found

    Considerations in the Development of a Scientific Social Work

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    A key issue in social work\u27s struggle to develop a legitimate and distinct knowledge base is the development of a scientific model suited to the needs and objectives of the profession. Although various approaches have been proposed, they have tended to dichotomize the issues into one of science versus nonscience. In response to this situation, this paper presents an integrative approach to the development of a scientific social work. In addition, it is argued that values can (and should) be an integral part of a scientific approach and that they are legitimate criteria for the evaluation of social theories

    A supressor mutation in Escherichia coli

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    Nutritionally deficient mutant strains of bacteria (auxotrophs) are often capable of undergoing "reversion," giving rise to strains having the wild type nutritional state (prototrophs). It is usually impossible to determine whether the prototrophs are true back-mutants, or whether the wild phenotype is restored by the action of an independent suppressor mutation. An auxotroph requiring histidine was isolated from strain B/r of Escherichia coli (which grows well on minimal medium) after ultraviolet irradiation and layering(1). Some time later, the histidineless strain was irradiated with ultraviolet and subjected to penicillin screening(2,3) Among the mutants isolated was one requiring serine or glycine in addition to histidine. This diauxotroph, strain M2, was thus characterized by two growth factor requirements acquired separately and serially, presumably by two mutational steps

    Rationality in Social Work: A Critical Examination

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    This paper critically examines the definitions and criteria for rationality in social work in light of western philosophic tradition. Rationality in social work is seen as instrumental (means-oriented) and individualistic rather than substantive (ends-oriented) and social. A set of criteria which expand the basis for making rationality claims in social work is suggested. These additional criteria aim to serve the valued social justice ends of social work practice

    Letters to the Editor Regarding NASW Press Censorship Issue

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    LETTERS TO THE EDITOR REGARDING NASW PRESS CENSORSHIP Marcia B. Cohen, Co-editor, Journal of Progressive Human Services Richard Hoefer, Editor, Journal of Policy Practice Tony Tripodi, Former Editor of Social Work Research Former Co-editor of Journal of Social Work Research and Evaluation Stanley L. Witkin, Former Editor-in-Chief, Social Work Elizabeth J. Clark, Executive Director, National Association of Social Workers (NASW

    A medium throughput rodent model of relapse from addiction with behavioral and pharmacological specificity

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    One of most formidable problems in the treatment of addiction is the high rate of relapse. The discovery of medicines to help mitigate relapse are aided by animal models that currently involve weeks of training and require surgical preparations and drug delivery devices. The present set of experiments was initiated to investigate a rapid 8-day screening method that utilizes food instead of intravenous drug administration. Male Sprague-Dawley rats were trained in a reinstatement paradigm in which every lever press produced a 45 mg food pellet concurrently paired with a light and tone. Behavior was subsequently extinguished with lever responses producing neither food nor food-associated stimuli. Reinstatement of responding was evaluated under conditions in which the first three responses of every 5 min time bin produced a food pellet along with food-associated stimuli. The mGlu5 receptor antagonists MPEP and MTEP produced a significant reduction in reinstatement while failing to alter responding where every response produced food. The cannabinoid CB1 receptor antagonist rimonabant and the mGlu2/3 receptor agonist LY379268 also selectively reduced reinstatement. Other compounds including clozapine, d-amphetamine, chlordiazepoxide, ABT-431, naltrexone and citalopram were without effect. The results suggest that relapse-like behavioral effects can be extended to non-pharmacological reinforcers. Drug effects demonstrated both behavioral and pharmacological specificity. The present experimental design thus allows for efficient and rapid assessment of the effects of drugs that might be useful in the treatment of addiction-associated relapse

    A progressive refinement approach for the visualisation of implicit surfaces

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    Visualising implicit surfaces with the ray casting method is a slow procedure. The design cycle of a new implicit surface is, therefore, fraught with long latency times as a user must wait for the surface to be rendered before being able to decide what changes should be introduced in the next iteration. In this paper, we present an attempt at reducing the design cycle of an implicit surface modeler by introducing a progressive refinement rendering approach to the visualisation of implicit surfaces. This progressive refinement renderer provides a quick previewing facility. It first displays a low quality estimate of what the final rendering is going to be and, as the computation progresses, increases the quality of this estimate at a steady rate. The progressive refinement algorithm is based on the adaptive subdivision of the viewing frustrum into smaller cells. An estimate for the variation of the implicit function inside each cell is obtained with an affine arithmetic range estimation technique. Overall, we show that our progressive refinement approach not only provides the user with visual feedback as the rendering advances but is also capable of completing the image faster than a conventional implicit surface rendering algorithm based on ray casting

    Chlamydia trachomatis Infection, Immunity, and Pregnancy Outcome

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    Chlamydia trachomatis can ascend from the cervix to the fallopian tubes and survive for long periods of time without causing symptoms. The immune response to infection clears the extracellular organisms but leads to development of a persistent intracellular infection. Repeated cycles of productive infection and persistence eventually induce tubal occlusion and infertility. Persistently infected cells continue to synthesize the chlamydial 60 kD heat shock protein (hsp60). Immunity to conserved regions of hsp60 may result in autoimmunity to human hsp60. Expression of hsp60 by the embryo and decidua during early pregnancy may reactivate hsp60-sensitized lymphocytes, disturb pregnancy-induced immune regulatory mechanisms, and lead to immune rejection of the embryo. Due to this mechanism women with tubal infertility who are sensitized to the human hsp60 may have a decreased probability of successful outcome after undergoing in vitro fertilization and embryo transfer

    Differential vaginal expression of interleukin-1 system cytokines in the presence of Mycoplasma hominis and Ureaplasma urealyticum in pregnant women.

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    OBJECTIVE: The genital mycoplasmas, Ureaplasma urealyticum and Mycoplasma hominis, are commonly identified in the vagina of healthy pregnant women. However, these microorganisms are the most common isolates from the amniotic fluids of women in preterm labor. The mechanisms responsible for vaginal colonization and ascent to the uterus remain undetermined. We evaluated the association between U. urealyticum and M. hominis vaginal colonization and the presence of pro-inflammatory and anti-inflammatory interleukin-1 system components in asymptomatic pregnant women of different ethnicities. METHODS: Vaginal specimens, obtained from 224 first trimester pregnant women, were assayed for interleukin-1beta (IL-1beta) and IL-1 receptor antagonist (IL-1ra) concentrations by ELISA. U. urealyticum and M. hominis vaginal colonization were identified by polymerase chain reaction (PCR). RESULTS: Vaginal colonization with M. hominis was identified in 37 (16.5%) women, and was more prevalent in black (18.9%) and Hispanic (20.9%) than in white (4.2%) women (p = 0.01). U. urealyticum was present in 84 (37.5%) women and there was no ethnic disparity in its detection. M. hominis colonization was associated with elevated median vaginal IL-1beta concentrations in both black women (p = 0.02) and Hispanic women (p = 0.04), and was unrelated to vaginal IL-1ra concentrations. In marked contrast, U. urealyticum colonization was associated with elevations in vaginal IL-1ra levels, but not with IL-1beta concentrations, in black women (p = 0.02) and Hispanic women (p < 0.0001) and marginally in white women (p = 0.06). CONCLUSION: M. hominis colonization in healthy pregnant women is associated with localized pro-inflammatory immune activation, while U. urealyticum colonization is associated with immune suppression

    Validation of learning style measures: implications for medical education practice

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    It is unclear which learners would most benefit from the more individualised, student-structured, interactive approaches characteristic of problem-based and computer-assisted learning. The validity of learning style measures is uncertain, and there is no unifying learning style construct identified to predict such learners. Objective  This study was conducted to validate learning style constructs and to identify the learners most likely to benefit from problem-based and computer-assisted curricula. Methods  Using a cross-sectional design, 3 established learning style inventories were administered to 97 post-Year 2 medical students. Cognitive personality was measured by the Group Embedded Figures Test, information processing by the Learning Styles Inventory, and instructional preference by the Learning Preference Inventory. The 11 subscales from the 3 inventories were factor-analysed to identify common learning constructs and to verify construct validity. Concurrent validity was determined by intercorrelations of the 11 subscales. Results  A total of 94 pre-clinical medical students completed all 3 inventories. Five meaningful learning style constructs were derived from the 11 subscales: student- versus teacher-structured learning; concrete versus abstract learning; passive versus active learning; individual versus group learning, and field-dependence versus field-independence. The concurrent validity of 10 of 11 subscales was supported by correlation analysis. Medical students most likely to thrive in a problem-based or computer-assisted learning environment would be expected to score highly on abstract, active and individual learning constructs and would be more field-independent. Conclusions  Learning style measures were validated in a medical student population and learning constructs were established for identifying learners who would most likely benefit from a problem-based or computer-assisted curriculum.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72443/1/j.1365-2929.2006.02476.x.pd

    Luteinizing Hormone-Releasing Hormone in the Vomeronasal System and Terminal Nerve of the Hamster a

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74742/1/j.1749-6632.1987.tb36300.x.pd
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