Showing papers by "University of South Florida published in 1990"

Derivation of some modern arc magmas by melting of young subducted lithosphere

Abstract: MOST volcanic rocks in modern island and continental arcs are probably derived from melting of the mantle wedge, induced by hydrous fluids released during dehydration reactions in the subducted lithosphere1. Arc tholeiitic and calc-alkaline basaltic magmas are produced by partial melting of the mantle, and then evolve by crystal fractionation (with or without assimilation and magma mixing) to more silicic magmas2—basalt, andesite, dacite and rhyolite suites. Although most arc magmas are generated by these petrogenetic processes, rocks with the geochemical characteristics of melts derived directly from the subducted lithosphere are present in some modern arcs where relatively young and hot lithosphere is being subducted. These andesites, dacites and sodic rhyolites (dacites seem to be the most common products) or their intrusive equivalents (tonalites and trondhjemites) are usually not associated with parental basaltic magmas3. Here we show that the trace-element geochemistry of these magmas (termed 'adakites') is consistent with a derivation by partial melting of the subducted slab, and in particular that subducting lithosphere younger than 25 Myr seems to be required for slab melting to occur.

A gene in the human major histocompatibility complex class II region controlling the class I antigen presentation pathway

Abstract: MAJOR histocompatibility complex (MHC) class I molecules export peptides to the cell surface for surveillance by cytotoxic T lymphocytes1-3. Intracellular peptide binding is critical for the proper assembly and transport of class I molecules4–6. This mechanism is impaired as a result of a non-functional peptide supply factor gene (PSF) in several human mutant cell lines with genomic lesions in the MHC. We have now identified PSF in the MHC class II region by deletion mapping in mutants and chromosome-walking. PSF is homologous to mammalian and bacterial ATP-dependent transport proteins, suggesting that it operates in the intracellular transport of peptides.

Toward a Technology of “Nonaversive” Behavioral Support:

Abstract: Nonaversive behavior management is an approach to supporting people with undesirable behaviors that integrates technology and values. Although this approach has attracted numerous proponents, more ...

Effects of choice making on the serious problem behaviors of students with severe handicaps.

Abstract: This study assessed the impact of choice making on the serious problem behaviors of 3 students with severe autism and/or mental retardation. In the context of within-subject reversal designs, the results showed consistently reduced levels of problem behaviors (e.g., aggression) when the students were given opportunities to make choices among instructional tasks and reinforcers. Additional data showed no systematic differences in the rate of correct responding between the two conditions. The results are discussed in relation to the continuing search for effective, nonintrusive solutions to the occurrence of serious problem behavior.

The Epidemiology of Childhood Psychiatric Disorders: Prevalence Findings from Recent Studies

Abstract: . While sharing a new emphasis upon identifying discrete psychiatric disorders in children and adolescents, epidemiological field studies conducted during the past decade have used diverse methods of case ascertainment and definition. Half used the multimethod-multistage approach to ascertain cases. Severity rating scales and measures of pervasiveness, parent-child concordance, and global functional impairment were employed to enhance the specificity of case definition. The majority of overall prevalence estimates of moderate to severe disorder range from 14 to 20%. Those investigations that use multiple methods to define caseness show greatest promise in identifying true cases in community samples.

A Conditioning Theory of the Etiology and Maintenance of Deviant Sexual Preference and Behavior

Abstract: Regarding the etiology of sexual deviance, Quinsey and Marshall (1983) have observed, With respect to the concept of inappropriate arousal itself, there are no theories of etiology which have other than laboratory demonstrations of plausibility or anecdotal support. We simply do not know how to account for individual differences in sexual arousal patterns. Clearly, developmental studies of the acquisition of sexual preferences should receive high priority. (p. 30)

Functional activation of human neutrophils by recombinant monocyte-derived neutrophil chemotactic factor/IL-8.

Abstract: Monocyte-derived neutrophil chemotactic factor (MDNCF)/IL-8, a novel cytokine, distinct from IL-1 and TNF was recently purified and cloned. This study was performed to investigate the biologic effect of recombinant MDNCF/IL-8 on human polymorphonuclear neutrophils (PMN) by assessment of their growth inhibitory activity against Candida albicans. The chemoattractant, FMLP was used as a positive control. We demonstrated that MDNCF/IL-8, similar to FMLP, effectively enhanced PMN-mediated anti-Candida activity. MDNCF/IL-8, from 1.0 to 1000 ng/mol, enhanced PMN-mediated anti-Candida activity, whereas FMLP was effective from 10(-10) to 10(-7) M. The optimal dose of MDNCF/IL-8 for PMN stimulation was 10 ng/ml which equalled the optimal chemoattractant dose. MDNCF/IL-8 itself, like FMLP, had no direct effect on Candida growth at any concentration and it stimulated antifungal activity only in PMN but not in monocytes. Interestingly, MDNCF/IL-8 failed to stimulate directly the production of superoxide from PMN or prime the respiratory burst of PMN exposed to FMLP. However, MDNCF/IL-8 was capable of releasing azurophilic enzymes from cytochalasin B-treated PMN into the extracellular space. Enhancement of PMN anti-Candida activity and release of azurophilic enzymes from PMN by MDNCF/IL-8 were inhibited in the presence of colchicine, which is a known inhibitor of degranulation. These results suggest that MDNCF/IL-8 induced antifungal action of PMN via oxygen-independent pathways. Furthermore, MDNCF/IL-8 induction of anti-Candida action by PMN was inhibited by pretreatment with Bordetella pertussis toxin, suggesting that enhancement of PMN antifungal activity by MDNCF/IL-8, as well as by FMLP, may be mediated by a GTP-binding protein.

Oxidation reactions in Parkinson's disease.

Abstract: Free radicals generated from oxidation reactions may contribute to the pathogenesis of Parkinson's disease (PD). Free radicals are capable of reacting almost instantaneously with membrane lipids and causing lipid peroxidation, membrane injury, and cell death. Dopamine is metabolized by oxidation reactions capable of generating free radicals. Recent evidence indicates that the substantia nigra of patients with PD contains increased iron, which enhances oxidation, and decreased glutathione, which protects against the formation of free radicals. Further, the end products of lipid peroxidation are increased in the substantia nigra of patients with PD, supporting the notions that free radicals are being generated and may contribute to dopamine neuronal death. This hypothesis suggests that antioxidant therapies may slow the rate of progression of PD and raises concern that metabolites of levodopa therapy may accelerate the rate of neuronal degeneration.

A generalization of starlike functions

Abstract: For every q. 0

Generating test data with enhanced context-free grammars

Abstract: The use of context-free grammars to improve functional testing of very-large-scale integrated circuits is described. It is shown that enhanced context-free grammars are effective tools for generating test data. The discussion covers preliminary considerations, the first tests, generating systematic tests, and testing subroutines. The author's experience using context-free grammars to generate tests for VLSI circuit simulators indicates that they are remarkably effective tools that virtually anyone can use to debug virtually any program. >

Internal fixation of the distal humerus: a biomechanical comparison of methods.

Abstract: Three commonly used configurations of various implants used for fixation of distal humeral fractures were quantitatively compared. The double plate construct, irrespective of plate type (1/3 tubular and/or 3.5 mm reconstruction plate), was significantly stronger, both in rigidity and fatigue testing, than cross screws or the single "Y" plate. If rigid stabilization of supracondylar or bicondylar distal humeral fractures is desired, then two plate constructs, at right angles (the ulna plate medially, the lateral plate posteriorly), are biomechanically optimal.

Hypothalamic-pituitary-adrenal axis functioning and cerebrospinal fluid corticotropin releasing hormone and corticotropin levels in alcoholics after recent and long-term abstinence

Abstract: • We assessed the plasma corticotropin (adrenocorticotropic hormone) and cortisol responses to ovine corticotropin releasing hormone (oCRH) and the cerebrospinal fluid levels of CRH and corticotropin in alcoholics at various durations of abstinence and compared these variables with age-equivalent controls. Alcoholics who were tested at 1 week of abstinence (n = 11) demonstrated a significantly attenuated corticotropin response to oCRH compared with their response at 3 weeks of abstinence. Nine of these alcoholic patients demonstrated a significantly blunted corticotropin response at both 1 and 3 weeks of abstinence compared with controls (n =15). A markedly exaggerated corticotropin response to oCRH, associated with tachycardia, was exhibited by 2 alcoholics at both 1 and 3 weeks of abstinence. Alcoholics who were abstinent greater than 3 weeks did not differ in their response to oCRH compared with controls. Controls demonstrated a significant inverse correlation between baseline cortisol levels and the cortisol response to oCRH. This correlation was not evident in any of the alcoholic groups, including those patients who were abstinent greater than 6 months. There was a positive correlation between cerebrospinal fluid concentrations of CRH and corticotropin in all patient groups. These findings indicated that alcoholics have significantly altered hypothalamic-pituitary-adrenal axis functioning up to 3 weeks following the cessation of drinking, with a more subtle impairment present for greater than 6 months following abstinence.

Index-based object recognition in pictorial data management

Abstract: We have been involved with formulating query processing strategies for an object-oriented, integrated, textual/iconic database management system. For this task, model-based representations of images by content are being used, as well as a new, efficient object recognition approach which also permits the efficients insertion and deletion of object models, called data-driven indexed hypotheses. This paper emphasizes the data management aspects of this approach: the insertion and deletion of object models, a performance/space trade-off which can be used to improve the recognition capabilities of our approach, and a secondary memory implementation of our approach

Human immunodeficiency virus type 1 envelope glycoprotein gp120 produces immune defects in CD4+ T lymphocytes by inhibiting interleukin 2 mRNA

Abstract: Envelope glycoprotein gp120 of human immunodeficiency virus type 1 (HIV-1) is known to inhibit T-cell function, but little is known about the mechanisms of this immunosuppression. Pretreatment of a CD4+ tetanus toxoid-specific T-cell clone with soluble gp120 was found to exert a dose-dependent inhibition of soluble antigen-driven or anti-CD3 monoclonal antibody-driven proliferative response, interleukin 2 (IL-2) production, and surface IL-2 receptor (IL-2R) alpha-chain expression, all of which were reversed by the addition of exogenous IL-2. mRNA for the gene encoding IL-2 was suppressed by treatment with gp120, but IL-2R gene transcription was not inhibited. Bypass activation of the T-cell clone with phorbol 12-myristate 13-acetate plus ionomycin was unaffected by gp120 pretreatment. Thus, gp120-CD4 interaction interferes with an essential role of the CD4 molecule in signal transduction through the CD3-antigen receptor (Ti) complex. Such a mechanism of gp120-induced immunosuppression, if operative in vivo, could contribute to the depressed specific immune responses associated with HIV infection.

Cloning and sequencing of a new gro transcript from activated human monocytes: expression in leukocytes and wound tissue.

Abstract: Using cDNA cloning, we have identified a new member of the gro/KC inflammatory protein superfamily (gro-beta) produced by activated human monocytes and neutrophils and expressed at sites of inflammation in vivo. The open reading frame encodes a protein with 91% sequence homology to the human gro protein. Interestingly, some of the amino acid substitutions are located at regions where proteolytic cleavage occurs in the gro protein generating biologically active peptides (neutrophil activating peptide III). These changes would likely alter the processing of the gro-beta peptide and suggest that peptides with biological activities different from those produced by gro-alpha are encoded by this transcript.

Aspect graphs: An introduction and survey of recent results

Abstract: The study of the aspect graph of a three-dimensional object has recently become an active area of research in computer vision. The aspect graph provides a complete enumeration of all possible distinct views of an object, given a model for viewpoint space and a definition for “distinct.” This article presents a tutorial introduction to the aspect graph, surveys the current state of the art in algorithms for automatically constructing aspect graphs, and describes some possible applications of aspect graphs in computer vision and computer graphics.

Consumer search behavior and sunk costs

Abstract: This paper presents the results of four economic experiments involving 41 undergraduate students who were assigned the task of searching for the lowest price from a known distribution of prices. Economic theory predicts that individuals should continue to draw until the expected gain of another search is less than the marginal search cost. Additionally, once individuals have made a draw and then continued, they should never return to a price drawn earlier (exercise recall). Both of these predictions are tested in the paper and the results show that behavior is not always consistent with them. It appears that individuals are making decisions based on the total return from searching, rather than simply the marginal return from another draw.

Examining the research base for child mental health services and policy.

Abstract: This article reviews the existing research base for child mental health services and policy. It emphasizes the importance of research that looks at the overall community-based system of care as the unit of analysis, and stresses the need to maintain a systems perspective, even when research is focused on components of the overall system. The review concludes that there is a need for a considerable increase in child mental health services research but also indicates that there has been a recent increase in research that has the potential of building a base to change policy. In particular, a need is identified for well-controlled studies that assess both clinical and cost outcomes and for studies that examine the mega issues of the organization and financing of systems of care.

Serum IgE and human immunodeficiency virus (HIV) infection.

Abstract: Human immunodeficiency virus infection is characterized by a progressive depletion of helper T-lymphocytes and, like allergic diseases, is associated with altered T cell regulation. Total serum IgE was measured in 67 infected male subjects, 27 uninfected heterosexual male subjects, and 18 uninfected homosexual male subjects. The mean IgE level (132 IU/ml) of infected subjects with a helper T-lymphocyte number less than or equal to 200/mm3 was significantly greater than mean IgE levels of the uninfected heterosexual (38 IU/ml) and homosexual (35 IU/ml) groups. IgE levels were inversely related to both helper T cell and suppressor/cytotoxic T cell numbers but not to IgG or IgA levels. The increase in IgE was not a reflection of an increased prevalence of atopic disease (allergic asthma, allergic rhinitis, or atopic dermatitis) in the infected subjects. The elevation of IgE may be related to a difference among the groups in T cell production of IgE regulatory lymphokines.

Degenerate cadmium oxide films for electronic devices

Abstract: Highly conducting and transparent cadmium oxide films have been deposited on Corning 7059 glass substrates by ion-beam sputtering and by spray pyrolysis. The electrical and optical properties of CdO films prepared by the two techniques are similar. Typical films of 0.5 μm thickness have electrical resistivities of (2–5) × 10-3 ohm-cm, carrier concentrations of approximately 1020 cm-3, and an optical transmission of higher than 70% in the wavelength range of 600–900 nm. An optical bandgap of 2.4–2.42 eV was deduced from the optical transmission data.

A Customer‐based Competitive Analysis for Logistics Decisions

Abstract: Evidence suggests that the recent interest in competitive strategy and competitive positioning, while good in itself, has resulted in the management of many firms placing too much emphasis on competitive performance and too little emphasis on customer expectations. This research in the chemical industry provides support for the conclusion that management needs to refocus on the customer if US companies are going to succeed in the increasingly competitive marketplace. A methodology is presented that can be used by management to collect and analyse customer‐based competitive data for use in establishing priorities for customer service expenditures.

Is buspirone effective for panic disorder

Abstract: Buspirone was compared with imipramine and placebo in the treatment of panic disorder in an 8-week, double-blind controlled study of 52 randomly assigned patients. The side effect profile of buspirone was less disruptive than that of imipramine. Buspirone was not significantly superior to placebo in its antipanic or anxiolytic effects in panic disorder patients.

Viruses in Source and Drinking Water

Abstract: All warm blooded animals harbor enteric viruses which are excreted in fecal material and can find their way into the aquatic environment. In addition fish, other lower animals and even plants release viruses which can find their way into water. Fortunately, most viruses are highly host specific and only the enteric viruses of humans appear to offer the greatest health concern for waterborne transmission. Human enteric viruses are able to exist for extended periods in the environment and many may survive conventional water and wastewater treatment. Waterborne transmission has now been well documented for many of the enteric viruses. While a direct association with the presence of virus in a water supply and illness has not been demonstrated for all enteric viruses, the presence of any of these viruses in drinking water should be considered a major health concern.

Low‐dose methotrexate compared with auranofin in adult rheumatoid arthritis

Abstract: Weekly treatment with low-dose oral methotrexate (MTX) was compared with daily auranofin (AUR) treatment in a 36-week double-blind, randomized, multicenter study of 281 patients with active, adult-onset rheumatoid arthritis. Both treatment groups showed significant improvement by the usual measures of clinical efficacy. The response with MTX occurred earlier and was consistently greater than that with AUR. An intent-to-treat analysis showed significantly greater improvement (P < 0.01) with MTX for painful and swollen joint counts and physician and patient global assessments of disease activity. Adverse reactions were reported more frequently in the AUR group, and more AUR-treated patients were withdrawn from the study because of toxicity. MTX was thus more effective and better tolerated than AUR in this study.

Detection of Horizontal Gene Transfer by Natural Transformation in Native and Introduced Species of Bacteria in Marine and Synthetic Sediments

Abstract: Both naturally occurring marine sediments and artificial sediments were used as supports for natural transformation of marine bacteria. While transformation of Pseudomonas stutzeri ZoBell suspended in artificial seawater was not detected when recipient cells and rifampin resistance DNA were loaded onto sterile sediment columns, transformation could be detected at frequencies 4 to 20 times that of spontaneous resistance when recipient cells and rifampin resistance DNA were loaded onto sterile sediment columns. Treatment of these columns with DNase I reduced transformation frequencies to levels comparable to those of spontaneous-resistance frequencies. Sediments with higher organic contents supported higher frequencies of transformation than did those with lower amounts of organic matter. Transformation was also detected when recipient cells and DNA were loaded on columns prepared from nonsterile sediments, although the frequencies of transformation were lower than when sterile sediments were used. Finally, nonsterilized sediments that were not supplemented with laboratory strains did not support detectable levels of transformation in sediment columns, but when these same sediments were transferred to filters and placed on complex media, transformation was detected at a frequency three times that for spontaneous resistance. This transformation frequency was partially reduced to levels near that for spontaneous resistance by the addition of DNase I to sediment filters. These results indicate that marine sediments facilitate the uptake and expression of exogenous DNA by transformable marine bacteria and that sediments are a more likely niche for natural transformation than the water column in the marine environment.