The Egyptian Cardiothoracic Surgeon (ECTS - E-Journal)
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Impulsivity in abstinent alcohol and polydrug dependence: a multidimensional approach.
No full textRATIONALE: Dependence on drugs and alcohol is associated with impaired impulse control, but deficits are rarely compared across individuals dependent on different substances using several measures within a single study. OBJECTIVES: We investigated impulsivity in abstinent substance-dependent individuals (AbD) using three complementary techniques: self-report, neuropsychological and neuroimaging. We hypothesised that AbDs would show increased impulsivity across modalities, and that this would depend on length of abstinence. METHODS: Data were collected from the ICCAM study: 57 control and 86 AbDs, comprising a group with a history of dependence on alcohol only (n = 27) and a group with history of dependence on multiple substances ("polydrug", n = 59). All participants completed self-report measures of impulsivity: Barratt Impulsiveness Scale, UPPS Impulsive Behaviour Scale, Behaviour Inhibition/Activation System and Obsessive-Compulsive Inventory. They also performed three behavioural tasks: Stop Signal, Intra-Extra Dimensional Set-Shift and Kirby Delay Discounting; and completed a Go/NoGo task during fMRI. RESULTS: AbDs scored significantly higher than controls on self-report measures, but alcohol and polydrug dependent groups did not differ significantly from each other. Polydrug participants had significantly higher discounting scores than both controls and alcohol participants. There were no group differences on the other behavioural measures or on the fMRI measure. CONCLUSIONS: The results suggest that the current set of self-report measures of impulsivity is more sensitive in abstinent individuals than the behavioural or fMRI measures of neuronal activity. This highlights the importance of developing behavioural measures to assess different, more relevant, aspects of impulsivity alongside corresponding cognitive challenges for fMRI
Interrogating Michel Foucault's Counter-Conduct: Theorising the Subjects and Practices of Resistance in Global Politics
No full textResistance, and its study, is on the rise: visible and politically discernible practices of dissent against sovereignty and economic exploitation, such as protesting, agitating and occupying, have received increased analytical attention in the past decade. This special issue provides much needed systematic attention to less visible practices of resistance or those not manifested in expressly political registers. It focuses on attempts to inventively modify, resist or escape the ways in which we are governed by interrogating critically the politics and ethics of resistance to “power that conducts”, expressed through Foucault's notion of “counter-conduct”. The contributions first theoretically interrogate, develop and refine the concept of “counter-conduct(s)”, offering a major statement of its importance for both the study of resistance and also its place in Foucault's work. Second, they provide inter/multi-disciplinary empirical investigations of counter-conduct in numerous thematic areas and spaces of global politics. Third, they explicitly reflect on variable and contingent forms of counter-conduct, examining its close relationship with conducting power. Finally, the special issue concertedly considers issues of methodology and method emerging from the study of counter-conduct and how these also recalibrate the study of governing power itself
Problem drug use prevalence estimation revisited:heterogeneity in capture-recapture and the role of external evidence
No full textBACKGROUND AND AIMS: Capture-recapture (CRC) analysis is recommended for estimating the prevalence of problem drug use or people who inject drugs (PWID). We aim to demonstrate how naive application of CRC can lead to highly misleading results, and to suggest how the problems might be overcome.METHODS: We present a case study of estimating the prevalence of PWID in Bristol, UK, applying CRC to lists in contact with three services. We assess: (i) sensitivity of results to different versions of the dominant (treatment) list: specifically, to inclusion of non-incident cases and of those who were referred directly from one of the other services; (ii) the impact of accounting for a novel covariate, housing instability; and (iii) consistency of CRC estimates with drug-related mortality data. We then incorporate formally the drug-related mortality data and lower bounds for prevalence alongside the CRC into a single coherent model.RESULTS: Five of 11 models fitted the full data equally well but generated widely varying prevalence estimates, from 2740 [95% confidence interval (CI) = 2670, 2840] to 6890 (95% CI = 3740, 17680). Results were highly sensitive to inclusion of non-incident cases, demonstrating the presence of considerable heterogeneity, and were sensitive to a lesser extent to inclusion of direct referrals. A reduced data set including only incident cases and excluding referrals could be fitted by simpler models, and led to much greater consistency in estimates. Accounting for housing stability improved model fit considerably more than did the standard covariates of age and gender. External data provided validation of results and aided model selection, generating a final estimate of the number of PWID in Bristol in 2011 of 2770 [95% credible interval (Cr-I) = 2570, 3110] or 0.9% (95% Cr-I = 0.9, 1.0%) of the population aged 15-64 years.CONCLUSIONS: Steps can be taken to reduce bias in capture-recapture analysis, including: careful consideration of data sources, reduction of lists to less heterogeneous subsamples, use of covariates and formal incorporation of external data.</p
Unlocking the secrets of Lizzie’s and Halsey’s century-old miscellanea
No full textUsing old artefacts to gain insights into past events, figures and places has been all the rage of late – recent salient examples including the City of New York Scotland Yard’s History of Crime and the Battle of Waterloo . Such is its popularity, the technique even featured in an article in last year’s Bulletin on one of Tewkesbury’s most endearing eccentrics, the late Mrs Margot Greaves, whose husband, ‘Gee’, it now appears was once an honorary Ashanti chief ! For this new application, we focus on a collection of miscellanea accumulated around the time of the First World War by my grandparents, Lizzie and Halsey – to often fascinating effect
A sharp-interface Cartesian grid method for viscoelastic fluid flow in complex geometry
No full textComputational method on Cartesian mesh is popular in simulating fluid flow with moving boundaries of complex geometry. In this paper, a sharp-interface Cartesian grid method is proposed for the simulation of viscoelastic fluid flow. We implement a finite volume numerical scheme with an improved Rhie-Chow interpolation on the open-source platform OpenFOAM. The order of accuracy in space is shown to be second-order for Newtonian fluid flow and first-order for Oldroyd-B fluid flow. The correctness of our code is validated with the benchmark case of flow past a cylinder. The new sharp-interface Cartesian grid method is verified to correctly predict the viscoelastic stress on the surface of the cylinder. Simulation results of confined Oldroyd-B fluid flow past a pair of cylinders are also reported. A comparison between the proposed sharp-interface Cartesian grid method and a smoothed-interface immersed boundary method is carried out in terms of accuracy and efficiency at the end of this study
Intraguild predation by a salticid (Hyllus brevitarsus) on a large orb weaver (Nephila senegalensis)
No full textNovel minimal physiologically-based model for the prediction of passive tubular reabsorption and renal excretion clearance
No full textPurposeDevelop a minimal mechanistic model based on in vitro–in vivo extrapolation (IVIVE) principles to predict extent of passive tubular reabsorption. Assess the ability of the model developed to predict extent of passive tubular reabsorption (Freab) and renal excretion clearance (CLR) from in vitro permeability data and tubular physiological parameters.MethodsModel system parameters were informed by physiological data collated following extensive literature analysis. A database of clinical CLR was collated for 157 drugs. A subset of 45 drugs was selected for model validation; for those, Caco-2 permeability (Papp) data were measured under pH 6.5–7.4 gradient conditions and used to predict Freab and subsequently CLR. An empirical calibration approach was proposed to account for the effect of inter-assay/laboratory variation in Papp on the IVIVE of Freab.ResultsThe 5-compartmental model accounted for regional differences in tubular surface area and flow rates and successfully predicted the extent of tubular reabsorption of 45 drugs for which filtration and reabsorption were contributing to renal excretion. Subsequently, predicted CLR was within 3-fold of the observed values for 87% of drugs in this dataset, with an overall gmfe of 1.96. Consideration of the empirical calibration method improved overall prediction of CLR (gmfe = 1.73 for 34 drugs in the internal validation dataset), in particular for basic drugs and drugs with low extent of tubular reabsorption.ConclusionsThe novel 5-compartment model represents an important addition to the IVIVE toolbox for physiologically-based prediction of renal tubular reabsorption and CLR. Physiological basis of the model proposed allows its application in future mechanistic kidney models in preclinical species and human
