1,317 research outputs found

    Mental health problems: Are they or are they not a risk factor for dropout from drug treatment? A systematic review of the evidence

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    Background: A sizeable number of recent studies investigating whether clients with substance misuse and mental health problems (dual diagnosis clients) are at heightened risk of dropout from drug treatment have been published. It is timely that their findings are brought together in a comprehensive review of the current evidence. Aims: The aim of the review is to examine whether dually diagnosed clients are less likely to be retained in drug treatment than clients without mental health problems, and, if so, whether this varies for clients diagnosed with different types of mental health problems. Methods: The review considers peer-reviewed research published after 1 January 1990, which was located using the literature databases Medline and PsycInfo. Predefined search terms were used. Further papers were identified from the bibliographies of relevant publications. Findings: 58 studies (84% from the USA) met the inclusion criteria for the review. The findings suggest that for most clients, having a past history of mental health problems does not influence the likelihood of being retained in drug treatment. The body of evidence regarding concurrent mental health problems is contradictory. On the whole, the majority of studies suggest that neither presence nor severity of depressive, anxiety, or other Axis-I disorders is related to retention, but these findings are not entirely unequivocal, as a few studies report strong positive or negative associations between depression and anxiety disorders and retention. Few researchers looked separately at psychotic spectrum disorders hence no conclusions could be drawn. The presence of most personality disorders also did not appear to affect treatment tenure, with the exception of antisocial personality disorder, for which the evidence points towards a greater risk of dropout. Conclusions: The balance of evidence suggests that, overall, dual diagnosis clients with Axis-I disorders who seek treatment in drug treatment services are retained as well as clients without dual diagnosis. Subgroups of clients who appear more vulnerable to premature dropout include those with antisocial personality disorder. Methodological shortcomings of the reviewed studies and resulting implications for this review and future research are discussed

    Diel turbidity cycles in a headwater stream: evidence of nocturnal bioturbation?

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    Purpose: A small number of recent studies have linked daily cycles in stream turbidity to nocturnal bioturbation by aquatic fauna, principally crayfish, and demonstrated this process can significantly impact upon water quality under baseflow conditions. Adding to this limited body of research, we use high-resolution water quality monitoring data to investigate evidence of diel turbidity cycles in a lowland, headwater stream with a known signal crayfish (Pacifastacus leniusculus) population and explore a range of potential causal mechanisms. Materials and methods: Automatic bankside monitoring stations measured turbidity and other water quality parameters at 30-min resolution at three locations on the River Blackwater, Norfolk, UK during 2013. Specifically, we focused on two 20-day periods of baseflow conditions during January and April 2013 which displayed turbidity trends typical of winter and spring seasons, respectively. The turbidity time-series, which were smoothed with 6.5 hour Savitzky-Golay filters to highlight diel trends, were correlated against temperature, stage, dissolved oxygen and pH to assess the importance of abiotic influences on turbidity. Turbidity was also calibrated against suspended particulate matter (SPM) over a wide range of values via linear regression. Results and discussion: Pronounced diel turbidity cycles were found at two of the three sites under baseflow conditions during April. Spring night-time turbidity values consistently peaked between 21:00 and 04:00 with values increasing by ~10 nephelometric turbidity units (NTU) compared with the lowest recorded daytime values which occurred between 10:00 and 14:00. This translated into statistically significant increases in median midnight SPM concentration of up to 76% compared with midday, with night-time (18:00 – 05:30) SPM loads also up to 30% higher than that recorded during the daytime (06:00 – 17:30). Relating turbidity to other water quality parameters exhibiting diel cycles revealed there to be neither any correlation that might indicate a causal link, nor any obvious mechanistic connections to explain the temporal turbidity trends. Diel turbidity cycles were less prominent at all sites during the winter. Conclusions: Considering the seasonality and timing of elevated turbidity, visual observations of crayfish activity, and an absence of mechanistic connections with other water quality parameters, the results presented here are consistent with the hypothesis that nocturnal bioturbation is responsible for generating diel turbidity cycles under baseflow conditions in headwater streams. However, further research in a variety of fluvial environments is required to better assess the spatial extent, importance and causal mechanisms of this phenomenon

    The inevitable youthfulness of known high-redshift radio galaxies

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    Radio galaxies can be seen out to very high redshifts, where in principle they can serve as probes of the early evolution of the Universe. Here we show that for any model of radio-galaxy evolution in which the luminosity decreases with time after an initial rapid increase (that is, essentially all reasonable models), all observable high-redshift radio-galaxies must be seen when the lobes are less than 10^7 years old. This means that high-redshift radio galaxies can be used as a high-time-resolution probe of evolution in the early Universe. Moreover, this result helps to explain many observed trends of radio-galaxy properties with redshift [(i) the `alignment effect' of optical emission along radio-jet axes, (ii) the increased distortion in radio structure, (iii) the decrease in physical sizes, (iv) the increase in radio depolarisation, and (v) the increase in dust emission] without needing to invoke explanations based on cosmology or strong evolution of the surrounding intergalactic medium with cosmic time, thereby avoiding conflict with current theories of structure formation.Comment: To appear in Nature. 4 pages, 2 colour figures available on request. Also available at http://www-astro.physics.ox.ac.uk/~km

    Knockout studies reveal an important role of <i>plasmodium</i> lipoic acid protein ligase a1 for asexual blood stage parasite survival

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    Lipoic acid (LA) is a dithiol-containing cofactor that is essential for the function of a-keto acid dehydrogenase complexes. LA acts as a reversible acyl group acceptor and 'swinging arm' during acyl-coenzyme A formation. The cofactor is post-translationally attached to the acyl-transferase subunits of the multienzyme complexes through the action of octanoyl (lipoyl): &lt;i&gt;N&lt;/i&gt;-octanoyl (lipoyl) transferase (LipB) or lipoic acid protein ligases (LplA). Remarkably, apicomplexan parasites possess LA biosynthesis as well as scavenging pathways and the two pathways are distributed between mitochondrion and a vestigial organelle, the apicoplast. The apicoplast-specific LipB is dispensable for parasite growth due to functional redundancy of the parasite's lipoic acid/octanoic acid ligases/transferases. In this study, we show that &lt;i&gt;LplA1&lt;/i&gt; plays a pivotal role during the development of the erythrocytic stages of the malaria parasite. Gene disruptions in the human malaria parasite &lt;i&gt;P.falciparum&lt;/i&gt; consistently were unsuccessful while in the rodent malaria model parasite &lt;i&gt;P. berghei&lt;/i&gt; the &lt;i&gt;LplA1&lt;/i&gt; gene locus was targeted by knock-in and knockout constructs. However, the &lt;i&gt;LplA1&lt;/i&gt; &lt;sup&gt;(-)&lt;/sup&gt; mutant could not be cloned suggesting a critical role of LplA1 for asexual parasite growth &lt;i&gt;in vitro&lt;/i&gt; and &lt;i&gt;in vivo&lt;/i&gt;. These experimental genetics data suggest that lipoylation during expansion in red blood cells largely occurs through salvage from the host erythrocytes and subsequent ligation of LA to the target proteins of the malaria parasite

    Tracking habitus across a transnational professional field

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    The sociology of the professions has shied away from cross-national comparative work. Yet research in different professional jurisdictions emphasizes the transnational nature of professional fields. Further work is therefore needed that explores the extent to which transnational professional fields are characterized by unity or heterogeneity. To that end, this article presents the results of a qualitative interrogation of the habitus of partners in ‘Big 4’ professional service firms across, primarily, five countries (Bangladesh, Canada, France, Spain and the UK). Marked differences are observed between the partner habitus in Bangladesh and the other countries studied in terms of entrepreneurial and public service dispositions. In turn, these findings highlight the methodological relevance of habitus for both the sociology of the professions and comparative capitalism literatures: for the former, habitus aids in mapping the dynamics of transnational professional fields; for the latter, habitus can elucidate the informal norms and conventions of national business systems

    Social factors and obesity: an investigation of the role of health behaviours

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    OBJECTIVES: This study evaluated a behavioural model of the relation between social factors and obesity, in which differences in body mass index (BMI) across sociodemographic groups were hypothesized to be attributable to social group differences in health behaviours affecting energy expenditure (physical activity, diet and alcohol consumption and weight control). METHODS: A total of 8667 adults who participated in the 1995 Australian National Health and Nutrition Surveys provided data on a range of health factors including objectively measured height and weight, health behaviours, and social factors including family status, employment status, housing situation and migration status. RESULTS: Social factors remained significant predictors of BMI after controlling for all health behaviours. Neither social factors alone, nor health behaviours alone, adequately explained the variance in BMI. Gender-specific interactions were found between social factors and individual health behaviours. CONCLUSIONS: These results suggest that social factors moderate the relation between BMI and weight-related behaviours, and that the mechanisms underlying sociodemographic group differences in obesity may vary among men and women. Additional factors are likely to act in conjunction with current health behaviours to explain variation in obesity prevalence across sociodemographic groups.<br /
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