367 research outputs found

    The simulation heuristic, paranoia, and social anxiety in a non-clinical sample

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    Background and objectives: Quality of reasoning within non-clinical paranoia and mental simulation of future paranoia themed events was investigated by use of a simulation task to determine whether paranoid individuals would be restricted or more adept at reasoning about paranoia relevant material in comparison to a social anxiety group and a group with low paranoia and social anxiety. Method: Participants (N = 63) were divided into the three groups based on paranoia and social anxiety scores. They were presented with the beginning and end of an imaginary situation and were asked to describe, step-by-step, what they imagined would happen between those two points. They were also administered a beads task to evaluate the jumping to conclusion decision making bias. Results: The prediction of more adept reasoning was not supported for paranoia. However, the social anxiety comparison group on average better simulated a scenario with congruent (socially anxious) thematic content compared to ones with non-congruent content. Further, in an exploratory analysis, jumping to conclusions bias was found to be positively related to goodness of simulation for paranoia themed scenarios within the paranoia group. Limitations: Study groups were relatively small and so power was an issue. Conclusion: The results are discussed in the context of the sometimes paradoxical findings in the area of cognitive biases and paranoia

    Abnormal negative feedback processing in first episode schizophrenia: evidence from an oculomotor rule switching task

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    Background. Previous studies have shown that patients with schizophrenia are impaired on executive tasks, where positive and negative feedbacks are used to update task rules or switch attention. However, research to date using saccadic tasks has not revealed clear deficits in task switching in these patients. The present study used an oculomotor ‘ rule switching ’ task to investigate the use of negative feedback when switching between task rules in people with schizophrenia. Method. A total of 50 patients with first episode schizophrenia and 25 healthy controls performed a task in which the association between a centrally presented visual cue and the direction of a saccade could change from trial to trial. Rule changes were heralded by an unexpected negative feedback, indicating that the cue-response mapping had reversed. Results. Schizophrenia patients were found to make increased errors following a rule switch, but these were almost entirely the result of executing saccades away from the location at which the negative feedback had been presented on the preceding trial. This impairment in negative feedback processing was independent of IQ. Conclusions. The results not only confirm the existence of a basic deficit in stimulus–response rule switching in schizophrenia, but also suggest that this arises from aberrant processing of response outcomes, resulting in a failure to appropriately update rules. The findings are discussed in the context of neurological and pharmacological abnormalities in the conditions that may disrupt prediction error signalling in schizophrenia

    Socially-Mediated Internet Surveys (SMIS): Recruiting participants for online experiments

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    The Socially Mediated Internet Survey (SMIS) method is a cost-effective technique used to obtain web-based, adult samples for experimental research in political science. SMIS engages central figures in online social networks to help recruit participants among visitors to these websites, yielding sizable samples for experimental research. We present data from six samples collected using the SMIS method and compare them to those gathered by other sampling approaches such as Amazon's Mechanical Turk. While not representative of the general adult population, our SMIS samples are significantly more diverse than undergraduate convenience samples, not only demographically but also politically. We discuss the applicability of the method to experimental research and its usefulness for obtaining samples of special, politically relevant subpopulations such as political sophisticates and activists. We argue that the diversity of SMIS samples, along with the ability to capture highly engaged citizens, can circumvent questions about the artificiality of political behavior experiments entirely based on student samples and help to document sources of heterogeneous experimental treatment effects

    Analysis of the microbial community associated with a bioprocess system for bioremediation of thiocyanate- and cyanide-laden mine water effluents

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    Gold extraction by cyanidation from refractory gold ores results in the formation of thiocyanate- and cyanide-contaminated wastewater effluents that must be treated before recycle or discard. Activated sludge processes, such as ASTER™, can be used for biodegradation of these effluent streams. The destruction of these compounds is catalyzed by a mixed microbial culture, however, very little is known about the community composition and metabolic potential of the thiocyanate- and cyanide-degrading microorganisms within the community. Here we describe our on-going attempts to better understand the key microorganisms, within the ASTER™ bioprocess, that contribute to the destruction of thiocyanate and cyanide, and how this knowledge relates to further process optimisation

    Evaluation of the ASTERTM process in the presence of suspended solids

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    The ability to recycle and reuse process water is a major contributing factor toward increased sustainability in the mining industry. However, the presence of toxic compounds has prevented this in most bioleaching operations. The ASTERTM process has been used for the bioremediation of cyanide (CN) and thiocyanate (SCN−) containing effluents at demonstration and commercial scale, increasing the potential for recycling of the treated effluent. The process relies on a complex consortium of microorganisms and laboratory tests have shown that the biomass retention, in suspended flocs or attached biofilm, significantly improved SCN− degradation rates. The current research evaluated the process performance in the presence of suspended solids (up to 5.5% m/v) ahead of implementation at a site where complete tailings removal is not possible. Experiments were performed in four 1 l CSTRs (with three primary reactors in parallel at an 8 h residence time, feeding one secondary reactor at a 2.7 h residence time). Stable operation at the design specifications (5.5% solids, 100 mg/l SCN− feed, effluent SCN− 57 mg/l/h was achieved, despite no obvious floc formation. Microbial ecology studies (16S rRNA clone library) revealed reduced diversity relative to reactors operated without suspended solids

    Early detection and early intervention in prison : improving outcomes and reducing prison returns

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    Our aim was to investigate whether early detection was feasible in prison and whether it could improve mental health outcomes in young prisoners. A secondary aim was to explore whether it can reduce returns to prison. Between 2011 and 2014, a total of 2115 young prisoners were screened, 94 (4.4%) met criteria for ultra-high risk for psychosis and were offered an intervention, 52 actually received it. Return to prison data were sought on the 52 participants, receiving a formal intervention. Of the 52 prisoners who received an intervention, 30.8% returned to custody compared to national average reconviction rates of between 45.4 and 66.5%. Our results suggest that early detection is a feasible option in a prison setting, improving mental health outcomes and reducing returns to prison. Mental health outcomes were recorded for a sub-sample of those receiving the intervention. The results indicated statistically significant improvements on measures of depression, anxiety and psychological distress

    The influence of procedural volume and proficiency gain on mortality from upper GI endoscopic mucosal resection

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    OBJECTIVE: Endoscopic mucosal resection (EMR) is established for the management of benign and early malignant upper GI disease. The aim of this observational study was to establish the effect of endoscopist procedural volume on mortality. DESIGN: Patients undergoing upper GI EMR between 1997 and 2012 were identified from the Hospital Episode Statistics database. The primary outcome was 30-day mortality and secondary outcomes were 90-day mortality, requirement for emergency intervention and elective cancer re-intervention. Risk-adjusted cumulative sum (RA-CUSUM) analysis was used to assess patient mortality risk during initial stage of endoscopist proficiency gain and the effect of endoscopist and hospital volume. Mortality was compared before and after the change point or threshold in the RA-CUSUM curve. RESULTS: 11 051 patients underwent upper GI EMR. Endoscopist procedure volume was an independent predictor of 30-day mortality. Fifty-eight per cent of EMR procedures were performed by endoscopists with annual volume of 2 cases or less, and had a higher 30-day and 90-day mortality rate for patients with cancer, 6.1% vs 0.4% (p<0.001) and 12% vs 2.1% (p<0.001), respectively. The requirement for emergency intervention after EMR for cancer was also greater with low volume endoscopists (1.8% vs 0.1%, p=0.002). In patients with cancer, the RA-CUSUM curve change points for 30-day mortality and elective re-intervention were 4 cases and 43 cases, respectively. CONCLUSIONS: EMR performed by high volume endoscopists is associated with reduced adverse outcomes. In order to reach proficiency, appropriate training and procedural volume accreditation training programmes are needed nationally

    Self-report and behavioural measures of impulsivity as predictors of impulsive behaviour and psychopathology in male prisoners

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    Impulsivity is an important factor in adverse outcomes such as substance use, problem gambling and psychopathology. Extensive research has shown these negative outcomes are associated with both self-report and behavioural measures of impulsivity but these two measurement domains are not themselves associated. There has been limited research in prison samples. This is surprising given the high variability in impulsive behaviours that should make them ideal for investigating the convergence of impulsivity measures. Using a cross sectional design we investigated the associations of impulsivity – measured by self-report and two behavioural indices - with substance misuse and psychopathology in a sample of 72 male prisoners. We found higher self-reported impulsivity was associated with crack/cocaine use, problem gambling and a positive screen for personality disorder. Behavioural measures of impulsivity showed fewer associations with problematic behaviours; they were also not independent predictors of impulsive behaviour in multivariate analyses. These data suggest that self-reported impulsivity is a more consistent predictor of problematic behaviours than behavioural measures in a sample of people with significant levels of substance use and psychopathology. This difference could reflect relevance of self-reported measures to emotionally charged decision-making in daily life compared to more neutral behavioural measures
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