A meta-analytic investigation of the role of reward on inhibitory control

Contemporary theories predict that Inhibitory Control (IC) can be improved when rewards are available for successfully inhibiting. In non-clinical samples empirical research has demonstrated some support, however 'null' findings have also been published. The aim of this meta-analysis was to clarify the magnitude of the effect of reward on IC, and identify potential moderators. Seventy-three articles (contributing k = 80 studies) were identified from Pubmed, PsychInfo and Scopus, published between 1997 - 2020, using a systematic search strategy. A random effects meta-analysis was performed on effect sizes generated from IC tasks which included rewarded and non-rewarded inhibition trials. Moderator analyses were conducted on clinical samples (vs 'healthy controls'), task type (Go/No-Go vs Stop Signal vs Flanker vs Simon vs Stroop vs Anti-Saccade), reward type (monetary vs points vs other), and age (adults vs children). The prospect of reward for successful inhibition significantly improved IC (SMD=0.429 (95% CI= 0.288, 0.570), I2=96.7%), compared to no reward conditions/groups. This finding was robust against influential cases and outliers. The significant effect was present across all IC tasks. There was no evidence the effect was moderated by type of reward, age or clinical samples. Moderator analyses did not resolve considerable heterogeneity. Findings suggest that IC is a transient state that fluctuates in response to motivations driven by reward. Future research might examine the potential of improving inhibitory control through rewards as a behavioural intervention

Stress effects of silica particles in a semiconductor package molding compound

The stresses induced on a silicon chip encased in an epoxy compound are considered due to absorption of moisture and the presence of silica particles in the coating. A range of different approaches are considered including a one-dimensional model for the curvature due to the absorption of water in a bi-lateral sheet, numerical simulations for the stress at the molding compound-silicon die interface and a two-dimensional model in the complex plane

Conceptions of agency and constraint for HIV-positive patients and healthcare workers to support long-term engagement with antiretroviral therapy care in Khayelitsha, South Africa.

In the context of the optimism around antiretroviral therapy (ART) as prevention of HIV/AIDS, addressing the barriers to long-term ART adherence is critical. This is particularly important given the tendency to individualise or use a blame discourse when exploring why HIV-infected patients "fail" to adequately adhere to ART, and not sufficiently exploring contextual reasons for poor adherence that may require varying solutions. This study took place at three clinics and one hospital in Khayelitsha, South Africa, to document the contextual factors that challenged ART adherence in this community. Interviews were conducted with 20 HIV-infected patients who had defaulted on their ART and were subsequently admitted to Khayelitsha hospital for clinical complications, and 9 ART service providers including doctors, nurses and HIV counsellors. Interviews assessed the reasons patients defaulted on ART and explored ways this could be prevented. Data from both groups were analysed collectively using thematic analysis. While the interviews revealed a landscape of environmental risks threatening adherence to ART, all patients managed to overcome the identified barriers at some point in their treatment phase, indicating the fluidity of patients' needs and decision making. Patients reported that distrustful relationships with service providers could inhibit their understanding of ART and/or interrupt their follow-up at clinics. Patients described their rationale and agency underlying non-adherence, such as testing their bodies' physical limits without ART medication. The study speaks to the need to appreciate contextual social and structural barriers related to ART adherence, and how these are negotiated differently by specific sub-groups, to support an appropriate response. It is imperative to not solely emphasise loss to follow-up but also assess patients' subjective trajectory of their ART journey, decision making and agency with adhering to ART, their relations with healthcare workers, and how these dynamics are intertwined with broader constraints in health systems

Seasonal range fidelity of a megaherbivore in response to environmental change

For large herbivores living in highly dynamic environments, maintaining range fidelity has the potential to facilitate the exploitation of predictable resources while minimising energy expenditure. We evaluate this expectation by examining how the seasonal range fidelity of African elephants (Loxodonta africana) in the Kruger National Park, South Africa is affected by spatiotemporal variation in environmental conditions (vegetation quality, temperature, rainfall, and fire). Eight-years of GPS collar data were used to analyse the similarity in seasonal utilisation distributions for thirteen family groups. Elephants exhibited remarkable consistency in their seasonal range fidelity across the study with rainfall emerging as a key driver of space-use. Within years, high range fidelity from summer to autumn and from autumn to winter was driven by increased rainfall and the retention of high-quality vegetation. Across years, sequential autumn seasons demonstrated the lowest levels of range fidelity due to inter-annual variability in the wet to dry season transition, resulting in unpredictable resource availability. Understanding seasonal space use is important for determining the effects of future variability in environmental conditions on elephant populations, particularly when it comes to management interventions. Indeed, over the coming decades climate change is predicted to drive greater variability in rainfall and elevated temperatures in African savanna ecosystems. The impacts of climate change also present particular challenges for elephants living in fragmented or human-transformed habitats where the opportunity for seasonal range shifts are greatly constrained

A Pilot Survey for the H2_2O Southern Galactic Plane Survey (HOPS)

We describe observations with the Mopra radiotelescope designed to assess the feasibility of the H$_2$O maser southern Galactic plane survey (HOPS). We mapped two one-square-degree regions along the Galactic plane using the new 12 mm receiver and the UNSW Mopra spectrometer (MOPS). We covered the entire spectrum between 19.5 and 27.5 GHz using this setup with the main aims of finding out which spectral lines can be detected with a quick mapping survey. We report on detected emission from H$_2$O masers, NH$_3$ inversion transitions (1,1), (2,2) and (3,3), HC$_3$N (3-2), as well as several radio recombination lines.Comment: accepted by PAS

Disseminated tuberculosis among hospitalised HIV patients in South Africa: a common condition that can be rapidly diagnosed using urine-based assays.

HIV-associated disseminated TB (tuberculosis) has been under-recognised and poorly characterised. Blood culture is the gold-standard diagnostic test, but is expensive, slow, and may under-diagnose TB dissemination. In a cohort of hospitalised HIV patients, we aimed to report the prevalence of TB-blood-culture positivity, performance of rapid diagnostics as diagnostic surrogates, and better characterise the clinical phenotype of disseminated TB. HIV-inpatients were systematically investigated using sputum, urine and blood testing. Overall, 132/410 (32.2%) patients had confirmed TB; 41/132 (31.1%) had a positive TB blood culture, of these 9/41 (22.0%) died within 90-days. In contrast to sputum diagnostics, urine Xpert and urine-lipoarabinomannan (LAM) combined identified 88% of TB blood-culture-positive patients, including 9/9 who died within 90-days. For confirmed-TB patients, half the variation in major clinical variables was captured on two principle components (PCs). Urine Xpert, urine LAM and TB-blood-culture positive patients clustered similarly on these axes, distinctly from patients with localised disease. Total number of positive tests from urine Xpert, urine LAM and MTB-blood-culture correlated with PCs (p < 0.001 for both). PC1&PC2 independently predicted 90-day mortality (ORs 2.6, 95%CI = 1.3-6.4; and 2.4, 95%CI = 1.3-4.5, respectively). Rather than being a non-specific diagnosis, disseminated TB is a distinct, life-threatening condition, which can be diagnosed using rapid urine-based tests, and warrants specific interventional trials

Diagnostic accuracy, incremental yield and prognostic value of Determine TB-LAM for routine diagnostic testing for tuberculosis in HIV-infected patients requiring acute hospital admission in South Africa: a prospective cohort

Abstract Background We previously reported that one-third of HIV-positive adults requiring medical admission to a South African district hospital had laboratory-confirmed tuberculosis (TB) and that almost two-thirds of cases could be rapidly diagnosed using Xpert MTB/RIF-testing of concentrated urine samples obtained on the first day of admission. Implementation of urine-based, routine, point-of-care TB screening is an attractive intervention that might be facilitated by use of a simple, low-cost diagnostic tool, such as the Determine TB-LAM lateral-flow rapid test for HIV-associated TB. Methods Sputum, urine and blood samples were systematically obtained from unselected HIV-positive adults within 24 hours of admission to a South African township hospital. Additional clinical samples were obtained during hospitalization as clinically indicated. TB was defined by the detection of Mycobacterium tuberculosis in any sample using Xpert MTB/RIF or liquid culture. The diagnostic yield, accuracy and prognostic value of urine-lipoarabinomannan (LAM) testing were determined, but urine-LAM results did not inform treatment decisions. Results Consecutive HIV-positive adult acute medical admissions not already receiving TB treatment (n = 427) were enrolled regardless of clinical presentation or symptoms. TB was diagnosed in 139 patients (TB prevalence 32.6%; median CD4 count 80 cells/μL). In the first 24 hours of admission, sputum (spot and/or induced) samples were obtained from 37.0% of patients and urine samples from 99.5% of patients (P < 0.001). The diagnostic yields from these specimens were 19.4% (n = 27/139) for sputum-microscopy, 26.6% (n = 37/139) for sputum-Xpert, 38.1% (n = 53/139) for urine-LAM and 52.5% (n = 73/139) for sputum-Xpert/urine-LAM combined (P < 0.01). Corresponding yields among patients with CD4 counts <100 cells/μL were 18.9%, 24.3%, 55.4% and 63.5%, respectively (P < 0.01). The diagnostic yield of urine-LAM was unrelated to respiratory symptoms, and LAM assay specificity (using a grade-2 cut-off) was 98.9% (274/277; 95% confidence interval [CI] 96.9–99.8). Among TB cases, positive urine-LAM status was strongly associated with mortality at 90 days (adjusted hazard ratio 4.20; 95% CI 1.50–11.75). Conclusions Routine testing for TB in newly admitted HIV-positive adults using Determine TB-LAM to test urine provides major incremental diagnostic yield with very high specificity when used in combination with sputum testing and has important utility among those without respiratory TB symptoms and/or unable to produce sputum. The assay also rapidly identifies individuals with a poor prognosis