949 resultados para Non-Negative Operators


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Shiftwork is a major source of stress for many worker's. This study highlights the role that organizational and psychosocial variables play in alleviating the negative health effects of 10 and 14-h shifts. It examines the direct and mediated effects of coping strategies, social support and control of shifts on work/non-work conflict and subjective health. Participants are 60 ambulance workers, aged 22 to SS years. A structural equation model with good fit demonstrates complex effects of social support from various sources (supervisors, co-workers and family), coping and control on work/non-work conflict and subjective health., Conceptually, the research contributes to the development of a theoretical framework that can assist in explaining how key psychosocial and organizational variables influence the psychological and physical symptoms experienced by shiftworkers. Copyright (C) 2002 John Wiley Sons, Ltd.

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In this paper we investigate the structure of non-representable preference relations. While there is a vast literature on different kinds of preference relations that can be represented by a real-valued utility function, very little is known or understood about preference relations that cannot be represented by a real-valued utility function. There has been no systematic analysis of the non-representation problem. In this paper we give a complete description of non-representable preference relations which are total preorders or chains. We introduce and study the properties of four classes of non-representable chains: long chains, planar chains, Aronszajn-like chains and Souslin chains. In the main theorem of the paper we prove that a chain is non-representable if and only it is a long chain, a planar chain, an Aronszajn-like chain or a Souslin chain. (C) 2002 Published by Elsevier Science B.V.

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We cloned the complete complementary DNA of an isolate of the hepatitis C virus, HCV-S1, into a tetra cycline-inducible expression vector and stably transfected it into two human hepatoma cell lines, Huh7 and HepG2. Twenty-six Huh7 and two HepG2-positive clones were obtained after preliminary screening. Two Huh7 (SH-7 and -9) and one HepG2 (G-19) clones were chosen for further characterisation. Expression of HCV proteins in these cells accumulated from 6 In to 4 days posttreatment. Full-length viral plus-strand RNA was detected by Northern analyses. Using RT-PCR and ribonuclease protection assay, we also detected the synthesis of minus-strand HCV RNA. Plus- and minus-strand viral RNA was still detected after treatment with actinomycin D. Indirect immunofluorescence staining with anti-E2, NS4B, and NS5A revealed that these proteins were mostly localised to the endoplasmic reticulum (ER). Culture media from tet-induced SH-9 cells was separated on sucrose density gradients and analysed for the presence of HCV RNA. Viral RNA levels peaked at two separate ranges, one with a buoyant density of 1.08 g/ml and another from 1.17 to 1.39 g/ml. Electron microscopy demonstrated the presence of subviral-like particles (approximately 20-25 nm in diameter) in the cytoplasm of SH-9 and G-19 cells, which were positively labelled by anti-HCV core antibodies. Anti-E2 antibodies strongly labelled cytoplasmic vesicular structures and some viral-like particles. Complete viral particles of about 50 nm which reacted with anti-E2 antibodies were observed in the culture media of tet-induced SH-9 cells following negative staining. Supernatant from tet-treated SH-9 cells was found to infect naive Huh7 and stable Huh7-human CD81 cells. (C) 2002 Elsevier Science (USA).

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The neuropathological changes associated with Huntington's disease (HD) are most marked in the head of the caudate nucleus and, to a lesser extent, in the putamen and globus pallidus, suggesting that at least part of the language impairments found in patients with HD may result from non-thalamic subcortical (NTS) pathology. The present study aimed to test the hypothesis that a signature profile of impaired language functions is found in patients who have sustained damage to the non-thalamic subcortex, either focally induced or resulting from neurodegenerative pathology. The language abilities of a group of patients with Huntington's disease (n=13) were compared with those of an age- and education-matched group of patients with chronic NTS lesions following stroke (n=13) and a non-neurologically impaired control group (n=13). The three groups were compared on language tasks that assessed both primary and more complex language abilities. The primary language battery consisted of The Western Aphasia Battery and The Boston Naming Test, whilst the more complex cognitive-linguistic battery employed selected subtests from The Test of Language Competence-Expanded, The Test of Word Knowledge and The Word Test-Revised. On many of the tests of primary language function from the Western Aphasia Battery, both the HD and NTS participants performed in a similar manner to the control participants. The language performances of the HD participants were significantly more impaired (p<0.05 using modified Bonferroni adjustments) than the control group, however, on various lexico-semantic tasks (e. g. the Boston Naming Test and providing definitions), on both single-word and sentence-level generative tasks (e. g. category fluency and formulating sentences), and on tasks which required interpretation of ambiguous, figurative and inferential meaning. The difficulties that patients with HD experienced with tasks assessing complex language abilities were strikingly similar, both qualitatively and quantitatively, to the language profile produced by NTS participants. The results provide evidence to suggest that a signature language profile is associated with damage to the non-thalamic subcortex resulting from either focal neurological insult or a degenerative disease.

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Community has taken on a new significance in Australian social policy discourse. Seemingly sound and morally justifiable, in the context Of neo-liberalism the language of community positions non-profit delivery of services as superior to state-provided services. As a consequence, non-profit community services are being centrally positioned to mediate the relationship between the state and citizen subjects. In the first part of this paper we trace some of the key historical developments in Australia's welfare state and patterns of governance that are propelling the non-profit sector firm the margins to the centre. The second section examines the relationship between Australia's shifting political landscape and the emerging welfare regime. One key feature of this new regime is the attempt to relocate citizenship away from the domain of the state and into that of civil society. The article concludes by sketching out some research themes, focusing, for example, on the impact of devolution of governance in terms of client rights and public accountability.

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Candida is an important nosocomial pathogen. This study was undertaken to provide information on the rate of candidaemia, to define the risks for candidaemia and to describe and account for the epidemiology of candidaemia at our institution between 1992 and 1999. The overall rate was 0.052 per 1000 patient days and 0.27 per 1000 discharges. The major risks for candidaemia were colonization at a non-sterile site (OR 3.85, 95%CI 1.80-9.09), total parenteral nutrition (TPN) in the absence of neutropenia (OR 11.8, 95%CI 4.5-35.4, P

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The first direct voltammetric response from a molybdenum enzyme under non-turnover conditions is reported. Cyclic voltammetry of dimethylsulfoxide reductase from Rhodobacter capsulatus reveals a reversible Mo-VI/V response at + 161 mV followed by a reversible Mo-V/IV response at -102 mV versus NHE at pH 8. The higher potential couple exhibits a pH dependence consistent with protonation upon reduction to the Mo-V state and we have determined the pK(a) for this semi-reduced species to be 9.0. The lower potential couple is pH independent within the range 5 < pH < 10. The optical spectrum of the Mo chromophore has been investigated with spectroelectrochemistry. At high potential, in its resting state, the enzyme exhibits a spectrum characteristic of the Mo-VI form. This changes significantly following bulk electrolysis (-400 mV versus NHE) at an optically transparent, indium-doped tin oxide working electrode, where a single visible electronic maximum at 632 nm is observed, which is comparable with spectra reported previously for the dithionite-reduced enzyme. This two-electron process is chemically reversible by reoxidizing the enzyme at the electrode in the absence of mediators or promoters. The activity of the enzyme has been established by observation of a catalytic current in the presence of DMSO at pH 8, where a sigmoidal (steady state) voltammogram is seen. Electronic supplementary material to this paper (Fig. S 1) can be obtained by using the Springer Link server located at http://dx.doi.org/10.1007/s00775-002-0374-y.

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The outcome effect occurs where an evaluator, who has knowledge of the outcome of a judge's decision , assesses the quality of the judgment of that decision maker. If the evaluator has knowledge of a negative outcome, then that knowledge negatively influences his or her assessment of the ex ante judgment. For instance, jurors in a lawsuit brought against an auditor for alleged negligence are informed of an undetected fraud, even though an unqualified opinion was issued. This paper reports the results of an experiment in an applied audit judgment setting that examined methods of mitigating the outcome effect by means of instructions. The results showed that simply instructing or warning the evaluator about the potential biasing effects of outcome information was only weakly effective. However, instructions that stressed either (1) the cognitive non-normativeness of the outcome effect or (2) the seriousness and gravity of the evaluation ameliorated the effect significantly. From a theoretical perspective, the results suggest that there may both motivational and cognitive components to the outcome effect. In all, the findings suggest awareness of the outcome effect and use of relatively nonintrusive instructions to evaluators may effectively counteract the potential for the outcome bias.

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The conditions under which blink startle facilitation can be found in anticipation of a reaction time task were investigated to resolve inconsistent findings across previous studies. Four groups of participants (n = 64) were presented with two visual stimuli, one predicting a reaction time task (S+) and the second presented alone (S-). Participants were asked to make a speeded response to the offset of the S+ (S1 paradigm) or were asked to respond to a tactile stimulus presented at the offset of the S+ (S1-S2 paradigm). Half of the participants in each paradigm condition received performance feedback. Overall, blink latency shortening and magnitude facilitation were larger during S+ than during S-. More detailed analyses, however, found these differences to be reliable only in the Feedback conditions. Ratings of S+ pleasantness did not change across the experiment. Electrodermal responses to S+ were larger than to S- in all groups with differential electrodermal responding emerging earlier in the S1 paradigm. Taken together, the data support the notion that startle facilitation can occur during non-aversive Pavlovian conditioning. (C) 2002 Elsevier Science B.V. All rights reserved.

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Animal-based theories of Pavlovian conditioning propose that patterning discriminations are solved using unique cues or immediate configuring. Recent studies with humans, however, provided evidence that in positive and negative patterning two different rules are utilized. The present experiment was designed to provide further support for this proposal by tracking the time course of the allocation of cognitive resources. One group was trained in a positive patterning; schedule (A-, B-, AB+) and a second in a negative patterning schedule (A+, B+, AB-). Electrodermal responses and secondary task probe reaction time were measured. In negative patterning, reaction times were slower during reinforced stimuli than during non-reinforced stimuli at both probe positions while there were no differences in positive patterning. These results support the assumption that negative patterning is solved using a rule that is more complex and requires more resources than does the rule employed to solve positive patterning. (C) 2001 Elsevier Science (USA).

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The phototrophic purple non-sulfur bacterium Rhodobacter capsulatus expresses a wide variety of complex redox proteins in response to changing environmental conditions. Here we report the construction and evaluation of an expression system for recombinant proteins in that organism which makes use of the dor promoter from the same organism. A generic expression vector, pDorEX, was constructed and used to express sulphite:cytochrome c oxidoreductase from Starkeya novella, a heterodimeric protein containing both molybdenum and haem c. The recombinant protein was secreted to the periplasm and its biochemical properties were very similar to those of the native enzyme. The pDorEX system therefore seems to be potentially useful for heterologous expression of multi-subunit proteins containing complex redox cofactors. (C) 2002 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.

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Objective To describe the decision-making processes used by men diagnosed with localized prostate cancer who were considering treatment. Patients and methods Men newly diagnosed with localized prostate cancer from outpatient urology clinics and urologist's private practices were approached before treatment. Their decision-making processes and information-seeking behaviour was assessed; demographic information was also obtained. Results Of 119 men approached, 108 (90%) were interviewed; 91% reported non-systematic decision processes, with deferral to the doctor, positive and negative recollections of others' cancer experiences, and the pre-existing belief that surgery is a better cancer treatment being most common. For systematic information processing the mean (SD, range) number of items considered was 4.19 (2.28, 0-11), with 57% of men considering four or fewer treatment/medical aspects of prostate cancer. Men most commonly considered cancer stage (59%), urinary incontinence (55%) and impotence (51%) after surgery, and low overall mortality (45%). Uncertainty about probabilities for cure was reported by 43% of men and fear of cancer spread by 37%. Men also described uncertainty about the probabilities of side-effects (27%), decisional uncertainty (25%) and anticipated decisional regret (18%). Overall, 73% of men sought information about prostate cancer from external sources, most commonly the Internet, followed by family and friends. Conclusions In general, men did not use information about medical treatments comprehensively or systematically when making treatment decisions, and their processing of medical information was biased by their previous beliefs about cancer and health. These findings have implications for the provision of informational and decisional support to men considering prostate cancer treatment.

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To establish a noncontagious control for the Ray thioglycollate test for the detection of Perkinsus in mollusks we evaluated nonviable stages of P. olseni for enlargement of hypnospores and blue/black iodine stain. Trophozoites made nonviable with formalin, irradiation or colchicine failed to swell in thioglycollate. They remained small and did not differentially stain in iodine. Trophozoites that had already developed into hypnospores in thioglycollate were rendered inactive by freezing, ethanol or formalin immersion. They retained their iodinophilic properties and thus could provide a partial control for the Ray Test.

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Background: Thalamotomy has been reported to be successful in ameliorating the motor symptoms of tremor and/or rigidity in people with Parkinson's disease (PD), emphasising the bona fide contribution of this subcortical nucleus to the neural circuitry subserving motor function. Despite evidence of parallel yet segregated associative and motor cortico-subcortical-cortical circuits, comparatively few studies have investigated the effects of this procedure on cognitive functions. In particular, research pertaining to the impact of thalamotomy on linguistic processes is fundamentally lacking. Aims: The purpose of this research was to investigate the effects of thalamotomy in the language dominant and non-dominant hemispheres on linguistic functioning, relative to operative theoretical models of subcortical participation in language. This paper compares the linguistic profiles of two males with PD, aged 75 years (10 years of formal education) and 62 years (22 years of formal education), subsequent to unilateral thalamotomy procedures within the language dominant and non-dominant hemispheres, respectively. Methods & Procedures: Comprehensive linguistic profiles comprising general and high-level linguistic abilities in addition to on-line semantic processing skills were compiled up to 1 month prior to surgery and 3 months post-operatively, within perceived on'' periods (i.e., when optimally medicated). Pre- and post-operative language performances were compared within-subjects to a group of 16 non-surgical Parkinson's controls (NSPD) and a group of 16 non-neurologically impaired adults (NC). Outcomes & Results: The findings of this research suggest a laterality effect with regard to the contribution of the thalamus to high-level linguistic abilities and, potentially, the temporal processing of semantic information. This outcome supports the application of high-level linguistic assessments and measures of semantic processing proficiency to the clinical management of individuals with dominant thalamic lesions. Conclusions: The results reported lend support to contemporary theories of dominant thalamic participation in language, serving to further elucidate our current understanding of the role of subcortical structures in mediating linguistic processes, relevant to cortical hemispheric dominance.