Uniting mathematics and biology for control of visceral leishmaniasis

The neglected tropical disease (NTD) visceral leishmaniasis (VL) has been targeted by the WHO for elimination as a public health problem on the Indian subcontinent by 2017 or earlier. To date there is a surprising scarcity of mathematical models capable of capturing VL disease dynamics, which are widely considered central to planning and assessing the efficacy of interventions. The few models that have been developed are examined, highlighting the necessity for better data to parameterise and fit these and future models. In particular, the characterisation and infectiousness of the different disease stages will be crucial to elimination. Modelling can then assist in establishing whether, when, and how the WHO VL elimination targets can be met

Tackling coolant freezing in generation-IV molten salt reactors

In this study we describe an experimental system designed to simulate the conditions of transient freezing which can occur in abnormal behaviour of molten salt reactors (MSRs). Freezing of coolant is indeed one of the main technical challenges preventing the deployment of MSR. First a novel experimental technique is presented by which it is possible to accurately track the growth of the solidified layer of fluid near a cold surface in an internal flow of liquid. This scenario simulates the possible solidification of a molten salt coolant over a cold wall inside the piping system of the MSR. Specifically, we conducted measurements using water as a simulant for the molten salt, and liquid nitrogen to achieve high heat removal rate at the wall. Particle image velocimetry and planar induced fluorescence were used as diagnostic techniques to track the growth of the solid layer. In addition this study describes a thermo-hydraulic model which has been used to characterise transient freezing in internal flow and compares the said model with the experiments. The numerical simulations were shown to be able to capture qualitatively and quantitatively all the essential processes involved in internal flow transient freezing. Accurate numerical predictive tools such the one presented in this work are essential in simulating the behaviour of MSR under accident conditions

Act Sing Play: A research evaluation of the instrumental and vocal learning by pupils in participant 'Act, Sing, Play' Primary schools across England

The overall aim of the year-long Act, Sing, Play (ASP) programme ‘was to evaluate whether music workshops had a bigger impact than drama workshops in terms of pupils’ mathematics and literacy attainment. The evaluation was based on a hypothesis that ‘participation in high- quality music instruction promotes educational attainment over and above instruction in other artistic pursuits’ (see Schellenberg, 2004) (NatCen, 2015, p3). Pupils in participant classes across 19 Primary schools were divided randomly into three arts intervention groups, two of which were music-focused (strings and voice), with the other group focused on drama (acting as a control). Each group had approximately n=10 pupils within each of the nineteen participant schools, with n=909 Year 2 pupils participating overall. An independent evaluation of the impact of the programme on mathematics and literacy attainment revealed no evidence that the ASP-music workshops had a greater impact than the ASP-drama workshops (NatCen, 2015). Nevertheless, the separate analyses reported here suggest that there was clear evidence of music learning in each of the two music-focused groups

Measurement of overall insecticidal effects in experimental hut trials

BACKGROUND: The 'overall insecticidal effect' is a key measure used to evaluate public health pesticides for indoor use in experimental hut trials. It depends on the proportion of mosquitoes that are killed out of those that enter the treated hut, intrinsic mortality in the control hut, and the ratio of mosquitoes entering the treatment hut to those entering the control hut. This paper critically examines the way the effect is defined, and discusses how it can be used to infer effectiveness of intervention programmes. FINDINGS: The overall insecticidal effect, as defined by the World Health Organization in 2006, can be negative when deterrence from entering the treated hut is high, even if all mosquitoes that enter are killed, wrongly suggesting that the insecticide enhances mosquito survival. Also in the absence of deterrence, even if the insecticide kills all mosquitoes in the treatment hut, the insecticidal effect is less than 100%, unless intrinsic mortality is nil. A proposed alternative definition for the measurement of the overall insecticidal effect has the desirable range of 0 to 1 (100%), provided mortality among non-repelled mosquitoes in the treated hut is less than the corresponding mortality in the control hut. This definition can be built upon to formulate the coverage-dependent insecticidal effectiveness of an intervention programme. Coverage-dependent population protection against feeding can be formulated similarly. CONCLUSIONS: This paper shows that the 2006 recommended quantity for measuring the overall insecticidal effect is problematic, and proposes an alternative quantity with more desirable propertie

The Co-Occurrence of Polypharmacy and Unmet Needs for Social Care in Older People: A Systematic Review

\ua9 2024 Laurie E. Davies et al.Polypharmacy is common in older people who often live with disability and dependency. The number of older people living with unmet needs for social care is also believed to be rising. Polypharmacy is simple to operationalise, whilst unmet needs are not routinely identified but are known to adversely affect health and well-being. Therefore, this systematic review aimed to investigate whether polypharmacy is a marker of unmet needs for social care in older people. Sixteen databases were searched from inception to January 2021. Studies were included if they reported quantitative data for polypharmacy ("multiple medicines") in relation to unmet needs for social care ("relative or absolute") in older people ("study criteria aged ≥55 years or mean age ≥55 in the sample as a whole or stratified data for the ≥55-year age group") and were from a high-income country (defined by the World Bank). Quality was assessed using the National Institute for Health tool for observational studies. Four studies were identified from 2,549 citations, and overall, the quality of evidence was low. Some older people using multiple medications had their social care needs met, whilst others did not. However, there is a clear rationale as to why polypharmacy may be linked to unmet social care needs. Given the limited studies identified in this review, future research should explore this further. The type of unmet need measure may be important to understand the nature of the relationship between the use of multiple medications and unmet social care needs

Characteristics of older unpaid carers in England: A study of social patterning from the English Longitudinal Study of Ageing

\ua9 2024 The Author(s). Published by Oxford University Press on behalf of the British Geriatrics Society.Background: A growing number of older people provide unpaid care, but contemporary research evidence on this group is limited. Aim: This study aims to describe the characteristics of older people who provide unpaid care and how these vary by socioeconomic position. Methods: Using recent information from the English Longitudinal Study of Ageing (ELSA wave 9, 2019), we analysed cross-sectional data on 1,282 unpaid carers aged ≥50. Data on sociodemographics, health, social wellbeing, care intensity and caregiver-recipient relationships were extracted. Total net non-pension wealth quintiles were used as a relative measure of socioeconomic position. Differences between the poorest and richest wealth quintiles were examined through logistic regression. Findings: Most older carers in ELSA were female and looking after another older person. Poor mental and physical health and social isolation were common, and socially patterned. Compared with carers in the middle wealth group, the poorest group were more likely to be living with the person they cared for (odds ratio (OR) 1.56 [95% confidence interval (CI) 1.03-2.36]) and more likely to experience loneliness (OR 2.29 [95% CI 1.42-3.69]), dependency (i.e.The need for help with activities of daily living) (OR 1.62 [95% CI 1.05-2.51]), chronic pain (OR 1.81 [95% CI 1.23-2.67]), a higher number of diseases (OR 1.75 [95% CI 1.15-2.65]) and fair/poor self-rated health (OR 2.59 [95% CI 1.79-3.76]). The poorest carers were also less likely to have a high quality of life (OR 0.51 [95% CI 0.33-0.80]) or be in work (OR 0.33 [95% CI 0.19-0.59]). Conclusion: Our findings suggest that financially disadvantaged unpaid carers (and their households) may have the greatest needs for intervention and support. Focussing resources on this group has potential to address social inequalities

Variations in visceral leishmaniasis burden, mortality and the pathway to care within Bihar, India

BACKGROUND: Visceral leishmaniasis (VL) has been targeted by the WHO for elimination as a public health problem (< 1 case/10,000 people/year) in the Indian sub-continent (ISC) by 2020. Bihar State in India, which accounts for the majority of cases in the ISC, remains a major target for this elimination effort. However, there is considerable spatial, temporal and sub-population variation in occurrence of the disease and the pathway to care, which is largely unexplored and a threat to achieving the target. METHODS: Data from 6081 suspected VL patients who reported being clinically diagnosed during 2012-2013 across eight districts in Bihar were analysed. Graphical comparisons and Chi-square tests were used to determine differences in the burden of identified cases by season, district, age and sex. Log-linear regression models were fitted to onset (of symptoms)-to-diagnosis and onset-to-treatment waiting times to estimate their associations with age, sex, district and various socio-economic factors (SEFs). Logistic regression models were used to identify factors associated with mortality. RESULTS: Comparisons of VL caseloads suggested an annual cycle peaking in January-March. A 17-fold variation in the burden of identified cases across districts and under-representation of young children (0-5 years) relative to age-specific populations in Bihar were observed. Women accounted for a significantly lower proportion of the reported cases than men (41 vs 59%, P < 0.0001). Age, district of residence, house wall materials, caste, treatment cost, travelling for diagnosis and the number of treatments for symptoms before diagnosis were identified as correlates of waiting times. Mortality was associated with age, district of residence, onset-to-treatment waiting time, treatment duration, cattle ownership and cost of diagnosis. CONCLUSIONS: The distribution of VL in Bihar is highly heterogeneous, and reported caseloads and associated mortality vary significantly across different districts, posing different challenges to the elimination campaign. Socio-economic factors are important correlates of these differences, suggesting that elimination will require tailoring to population and sub-population circumstances

The outcome at 12 months of very-Iow-birth-weight infants ventilated at Tygerberg Hospital

Objective. To determine the outcome at 1 year of age of a group of very-Iow-birth-weight (VLBW) infants, from urban and rural communities, ventilated at Tygerberg Hospital, W. Cape. Study design. Prospective descriptive study in which the prevalence of bronchopulmonary dysplasia (BPD), sensorineural deafness, intraventricular haemorrhage (IVH), retinopathy of prematurity (ROP) and abnormal motor developmental outcomes were determined in 153 ventilated VLBW infants from rural and urban areas. Of these, 69% were from lower socio-economic backgrounds. Main outcome measures. Attrition rates for rural and urban babies, BPD, ROP, IVH and abnormal motor development. Study population and setting. All ventilated VLBW infants discharged from the neonatal intensive care unit at Tygerberg Hospital over a 1-year period were followed up at 3-monthly intervals for 12 months. Results. BPD was diagnosed in 19% of the babies, with significantly more babies with birth weights under 1 000 g and gestational ages under 28 weeks having BPD. Of the babies with BPD, 25% had abnormal motor development at 1 year of age. Seven per cent of the babies had grade 3 or 4 ROP and 2,6% had sensorineural hearing loss. One hundred and seventeen (79%) of the infants attended the follow-up clinic until 12 months of age (corrected for prematurity). There were no significant differences in the number of babies followed up from rural or urban areas. Fourteen (11,9%) of the babies had abnormal motor development. A disturbing finding was that so many babies had spastic qiJadriplegia (8; 57%) versus diplegia (6; 43%).S Afr Med J 1995; 8

Thermal production of axino Dark Matter

We reconsider thermal production of axinos in the early universe, adding: a) missed terms in the axino interaction; b) production via gluon decays kinematically allowed by thermal masses; c) a precise modeling of reheating. We find an axino abunance a few times larger than previous computations.Comment: 6 pages, 2 figures. Final version, to appear on JHE

Cluster randomised trial and development of a sandfly sex pheromone lure to reduce Leishmania infantum infection

Introduction: Vector control tools are needed to combat leishmaniasis. A semi-synthetic version of a Lutzomyia longipalpis aggregation/sex pheromone (9-methlygermacrene-B) has been developed, and shown efficacy to attract sandflies in the lab and to chicken sheds in the field. Here, we present results from a cluster-randomised trial performed in Brazil where we test the efficacy of the pheromone deployed with insecticide, a novel lure-and-kill intervention, to reduce leishmaniasis transmission to the canine reservoir. Aim: Investigate the efficacy of sandfly sex pheromone baited + insecticide treated chicken roosts to reduce transmission of Leishmania infantum among the reservoir population (dogs). Methods: We conducted a cluster-randomised trial across 42 communities in Brazil. Pheromone lures plus insecticide were applied in 14 communities, and outcomes compared to that of 28 other communities that received either a placebo (sham lure + insecticide) or deltamethrin-impregnated collars fitted to dogs. We quantify the primary intervention effects by comparison of the number of uninfected dogs that seroconverted in each arm over the course of the 2-year trial. Results: A reduction in canine incidence is attributed to the pheromone + insecticide intervention, which is consistent across the levels of hierarchical analysis, though the errors are broad. The performance of the pheromone followed similar patterns as the collar arm which significantly reduced seroconversion incidence. Conclusion: These data represent the first trial of a synthetic vector pheromone applied in public health control, and the first cluster-randomised trial of dog collars in Brazil. Both methods show potential for the control of zoonotic visceral leishmaniasis in the Americas; developments of the pheromone lure-and-kill strategy are underway