Honey bee foraging distance depends on month and forage type

To investigate the distances at which honey bee foragers collect nectar and pollen, we analysed 5,484 decoded waggle dances made to natural forage sites to determine monthly foraging distance for each forage type. Firstly, we found significantly fewer overall dances made for pollen (16.8 %) than for non-pollen, presumably nectar (83.2 %; P < 2.2 × 10−23). When we analysed distance against month and forage type, there was a significant interaction between the two factors, which demonstrates that in some months, one forage type is collected at farther distances, but this would reverse in other months. Overall, these data suggest that distance, as a proxy for forage availability, is not significantly and consistently driven by need for one type of forage over the other

Bandit Models of Human Behavior: Reward Processing in Mental Disorders

Drawing an inspiration from behavioral studies of human decision making, we propose here a general parametric framework for multi-armed bandit problem, which extends the standard Thompson Sampling approach to incorporate reward processing biases associated with several neurological and psychiatric conditions, including Parkinson's and Alzheimer's diseases, attention-deficit/hyperactivity disorder (ADHD), addiction, and chronic pain. We demonstrate empirically that the proposed parametric approach can often outperform the baseline Thompson Sampling on a variety of datasets. Moreover, from the behavioral modeling perspective, our parametric framework can be viewed as a first step towards a unifying computational model capturing reward processing abnormalities across multiple mental conditions.Comment: Conference on Artificial General Intelligence, AGI-1

Economic, social and demographic impacts of drought on treatment adherence among people living with HIV in rural South Africa: A qualitative analysis

The 2015 El Niño-triggered drought in Southern Africa caused widespread economic and livelihood disruption in South Africa, imposing multiple physical and health challenges for rural populations including people living with HIV (PLHIV). We examined the economic, social and demographic impacts of drought drawing on 27 in-depth interviews in two cohorts of PLHIV in Hlabisa, uMkhanyakude district, KwaZulu-Natal. Thematic analysis revealed how drought-enforced soil water depletion, dried-up rivers, and dams culminated in a continuum of events such as loss of livestock, reduced agricultural production, and insufficient access to water and food which was understood to indirectly have a negative impact on HIV treatment adherence. This was mediated through disruptions in incomes, livelihoods and food systems, increased risk to general health, forced mobility and exacerbation of contextual vulnerabilities linked to poverty and unemployment. The systems approach, drawn from interview themes, hypothesises the complex pathways of plausible networks of impacts from drought through varying socioeconomic factors, exacerbating longstanding contextual precarity, and ultimately challenging HIV care utilisation. Understanding the multidimensional relationships between climate change, especially drought, and poor HIV care outcomes through the prism of contextual vulnerabilities is vital for shaping policy interventions

Modeling the Adaptive Role of Negative Signaling in Honey Bee Intraspecific Competition

Collective decision making in the social insects often proceeds via feedback cycles based on positive signaling. Negative signals have, however, been found in a few contexts in which costs exist for paying attention to no longer useful information. Here we incorporate new research on the specificity and context of the negative stop signal into an agent based model of honey bee foraging to explore the adaptive basis of negative signaling in the dance language. Our work suggests that the stop signal, by acting as a counterbalance to the waggle dance, allows colonies to rapidly shut down attacks on other colonies. This could be a key adaptation, as the costs of attacking a colony strong enough to defend itself are significant

Acceptability of a first-line anti-tuberculosis formulation for children: qualitative data from the SHINE trial.

SETTING: We conducted a qualitative exploration into the palatability and acceptability of a novel fixed-dose combination (FDC) anti-tuberculosis drug. This study was nested in the SHINE (Shorter treatment for minimal TB in children) trial, which compares the safety and efficacy of treating non-severe drug-susceptible tuberculosis (TB) with a 6 vs. 4 months anti-tuberculosis regimen in children aged 0-16 years. Participants were recruited in Cape Town, South Africa.OBJECTIVE: To describe the palatability and acceptability of a FDC of rifampicin, isoniazid and pyrazinamide among South African children and their caregivers in the SHINE trial.METHODS: We conducted 20 clinic observations of treatment administration, during which we conducted 16 semi-structured interviews with children and their caregivers. Data were organised thematically to report on experiences with administering and ingesting the FDC.RESULTS: Children and caregivers' experiences varied from delight to disgust. In general, participants said that the FDC compared favourably to other formulations. Pragmatic challenges such as dissolving the FDC and the time required to administer the FDC impeded caregivers' ability to integrate treatment into their daily routines. Drug manipulation was common among caregivers to improve TB treatment administration.CONCLUSION: This novel FDC appears acceptable for children, albeit with practical challenges to administration. Scale-up of FDC use should include supplementary intervention components to support caregivers

Investigating the clinico-anatomical dissociation in the behavioral variant of Alzheimer disease

BACKGROUND: We previously found temporoparietal-predominant atrophy patterns in the behavioral variant of Alzheimer's disease (bvAD), with relative sparing of frontal regions. Here, we aimed to understand the clinico-anatomical dissociation in bvAD based on alternative neuroimaging markers. METHODS: We retrospectively included 150 participants, including 29 bvAD, 28 "typical" amnestic-predominant AD (tAD), 28 behavioral variant of frontotemporal dementia (bvFTD), and 65 cognitively normal participants. Patients with bvAD were compared with other diagnostic groups on glucose metabolism and metabolic connectivity measured by [18F]FDG-PET, and on subcortical gray matter and white matter hyperintensity (WMH) volumes measured by MRI. A receiver-operating-characteristic-analysis was performed to determine the neuroimaging measures with highest diagnostic accuracy. RESULTS: bvAD and tAD showed predominant temporoparietal hypometabolism compared to controls, and did not differ in direct contrasts. However, overlaying statistical maps from contrasts between patients and controls revealed broader frontoinsular hypometabolism in bvAD than tAD, partially overlapping with bvFTD. bvAD showed greater anterior default mode network (DMN) involvement than tAD, mimicking bvFTD, and reduced connectivity of the posterior cingulate cortex with prefrontal regions. Analyses of WMH and subcortical volume showed closer resemblance of bvAD to tAD than to bvFTD, and larger amygdalar volumes in bvAD than tAD respectively. The top-3 discriminators for bvAD vs. bvFTD were FDG posterior-DMN-ratios (bvADbvFTD, area under the curve [AUC] range 0.85-0.91, all p tAD), MRI anterior-DMN-ratios (bvAD<tAD), FDG anterior-DMN-ratios (bvAD<tAD, AUC range 0.71-0.84, all p < 0.05). CONCLUSIONS: Subtle frontoinsular hypometabolism and anterior DMN involvement may underlie the prominent behavioral phenotype in bvAD

Findings from home-based HIV testing and facilitated linkage after scale-up of test and treat in rural South Africa: young people still missing

Objectives: The aim of the study was to estimate rates of linkage to HIV care and antiretroviral treatment (ART) initiation after the introduction of home‐based HIV counselling and testing (HBHCT) and telephone‐facilitated support for linkage in rural South Africa. / Methods: A population‐based prospective cohort study was carried out in KwaZulu Natal, South Africa. All residents aged ≥ 15 years were eligible for HBHCT. Those who tested positive and were not in care were referred for ART at one of 11 public‐sector clinics. Individuals who did not attend the clinic within 2 weeks were sent a short message service (SMS) reminder; those who had not attended after a further 2 weeks were telephoned by a nurse counsellor, to discuss concerns and encourage linkage. Kaplan–Meier methods were used to estimate the proportion of newly diagnosed individuals linking to care and initiating ART. / Results: Among 38 827 individuals visited, 26% accepted HBHCT. Uptake was higher in women than in men (30% versus 20%, respectively), but similar in people aged < 30 years and ≥ 30 years (28% versus 26%, respectively). A total of 784 (8%) tested HIV positive, of whom 427 (54%) were newly diagnosed. Within 6 months, 31% of women and 18% of men < 30 years old had linked to care, and 29% and 16%, respectively, had started ART. Among those ≥ 30 years, 41% of women and 38% of men had linked to care within 6 months, and 41% and 35%, respectively, had started ART. / Conclusions: Despite facilitated linkage, rates of timely linkage to care and ART initiation after HBHCT were very low, particularly among young men. Innovations are needed to provide effective HIV care and prevention interventions to young people, and thus maximize the benefits of universal test and treat

The need for an integrated approach for chronic disease research and care in Africa.

With the changing distribution of infectious diseases, and an increase in the burden of non-communicable diseases, low- and middle-income countries, including those in Africa, will need to expand their health care capacities to effectively respond to these epidemiological transitions. The interrelated risk factors for chronic infectious and non-communicable diseases and the need for long-term disease management, argue for combined strategies to understand their underlying causes and to design strategies for effective prevention and long-term care. Through multidisciplinary research and implementation partnerships, we advocate an integrated approach for research and healthcare for chronic diseases in Africa

Fungal iron availability during deep seated candidiasis is defined by a complex interplay involving systemic and local events

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