There are few evidence-based interventions to support caregiver mental health developed for low- and middle-income countries. Nae Umeed is a community-based group intervention developed with collaboratively with local community health workers in Uttarakhand, India primarily to promote mental wellbeing for caregivers and others. This pre–post study aimed to evaluate whether Nae Umeed improved mental health and social participation for people with mental distress, including caregivers. The intervention consisted of 14 structured group sessions facilitated by community health workers. Among 115 adult participants, 20% were caregivers and 80% were people with disability and other vulnerable community members; 62% had no formal education and 92% were female. Substantial and statistically significant improvements occurred in validated psychometric measures for mental health (12-Item General Health Questionnaire, Patient Health Questionnaire-9) and social participation (Participation Scale). Improvements occurred regardless of caregiver status. This intervention addressed mental health and social participation for marginalised groups that are typically without access to formal mental health care and findings suggest Nae Umeed improved mental health and social participation; however, a controlled community trial would be required to prove causation. Community-based group interventions are a promising approach to improving the mental health of vulnerable groups in South Asia.

The linear and nonlinear dynamics of an interface separating a thin liquid film and a hydrodynamically passive ambient medium, subject to normal electrostatic forcing, are investigated. A reduced-order model is developed for the case where both fluids are taken to be leaky dielectrics (LD). Cases of time periodic as well as steady forcing are studied. In the former case, an important result is the elucidation of two forms of resonant instability than can occur in LD films. These correspond to an inertial resonance due to mechanical inertia of the fluid and an inertialess resonance due to charge capacitance at the interface that is similar to mechanically forced films with an insoluble surfactant. In the case of steady forcing, the long-time dynamics exhibits spontaneous sliding as the interface approaches the wall, for the two limiting cases of a perfect conductor–perfect dielectric pair as well as a pair of perfect dielectrics. Under these limits, only the normal component of the Maxwell stress at the interface is significant and the interface dynamics resembles that of a Rayleigh–Taylor unstable interface. For a general pair of leaky dielectrics studied in the limit of fast relaxation times, the presence of interfacial charge prevents the onset of sliding. For the special case when the square of the conductivity ratio equals the permittivity ratio, the interface exhibits cascading structures, similar to those reported for the long-wave Marangoni instability.

The dynamics of an interface between a thin liquid–vapour bilayer undergoing evaporation is studied. Both phases are considered to be hydrodynamically and thermally active, with momentum and thermal inertia taken into account. A reduced-order model based on the weighted-residual integral boundary layer method is used to investigate the dynamical behaviour for two cases, viz., phase change in the absence of gravity and then phase change in the presence of gravity. In the first case, it is shown that evaporative instability may cause rupture of either liquid or vapour layer depending on system parameters. Close to interfacial rupture, the disjoining pressure due to intermolecular forces results in the formation of drops (bubbles) separated by a thin film for low liquid (vapour) hold-up. Momentum inertia is shown to have a stabilizing effect, while thermal inertia has a destabilizing effect. In the second case, evaporative suppression of Rayleigh–Taylor (R–T) instability shows emergence of up to two neutral wavenumbers. Weak nonlinear analysis of these neutral wavenumbers suggests that the instability may be either supercritical or subcritical depending on the rate of evaporation. At high rates of evaporation, both neutral wavenumbers are supercritical and computations on the interface evolution lead to nonlinear saturated steady states. Momentum inertia slows down the rate of interface deformation and results in an oscillatory approach to saturation. Thermal inertia results in larger interface deformation and the saturated steady state is shifted closer to the wall. At very low evaporation rates, only one neutral wavenumber of subcritical nature exists. The nonlinear evolution of the interface in this case is then similar to pure R–T instability, exhibiting spontaneous lateral sliding as it approaches the wall.

The nonlinear evolution of an interface between a perfect conducting liquid and a perfect dielectric gas subject to periodic electrostatic forcing is studied under the long-wave approximation. It is shown that inertial thin films become unstable to finite-wavelength Faraday modes at the onset, prior to the long-wave pillaring instability reported in the lubrication limit. It is further shown that the pillaring-mode instability is subcritical in nature, with the interface approaching either the top or the bottom wall, depending on the liquid–gas holdup. On the other hand, the Faraday modes exhibit subharmonic or harmonic oscillations that nonlinearly saturate to standing waves at low forcing amplitudes. Unlike the pillaring mode, wherein the interface approaches the wall, Faraday modes may exhibit saturated standing waves when the instability is subcritical. At higher forcing amplitudes, the interface may approach either wall, again depending on the liquid–gas holdup. It is also shown that a gravitationally unstable configuration of such thin films, under the long-wave approximation, cannot be stabilized by periodic electrostatic forcing, unlike mechanical Faraday forcing. In this case, it is observed that the interface exhibits oscillatory sliding behaviour, approaching the wall in an ‘earthworm-like’ motion.

A heavy-over-light configuration of a fluid bilayer may be stabilized in the presence of a phase change if the system consists of a single component. However, if the fluid is composed of a binary mixture with the more volatile component having the lower surface tension, it is known that a Marangoni instability occurs. This instability owes its origin to concentration gradients created by the phase change, even though the phase change otherwise has a stabilizing effect. In this study, it is shown via a nonlinear model under a long-wavelength approximation, that this Marangoni destabilization is insufficient to cause a rupture of the interface under practical operating conditions. Computations reveal that the stabilizing effect of the phase change dominates as the film becomes thin by reversing the direction of the Marangoni flow, thereby halting the instability and any hope of rupture.

Africa is experiencing a rapid increase in adult obesity and associated cardiometabolic diseases (CMDs). The H3Africa AWI-Gen Collaborative Centre was established to examine genomic and environmental factors that influence body composition, body fat distribution and CMD risk, with the aim to provide insights towards effective treatment and intervention strategies. It provides a research platform of over 10 500 participants, 40–60 years old, from Burkina Faso, Ghana, Kenya and South Africa. Following a process that involved community engagement, training of project staff and participant informed consent, participants were administered detailed questionnaires, anthropometric measurements were taken and biospecimens collected. This generated a wealth of demographic, health history, environmental, behavioural and biomarker data. The H3Africa SNP array will be used for genome-wide association studies. AWI-Gen is building capacity to perform large epidemiological, genomic and epigenomic studies across several African counties and strives to become a valuable resource for research collaborations in Africa.

There is limited evidence and lack of consensus whether second-hand smoke (SHS) increases risk of tuberculosis (TB), which has substantial implications for unrestricted smoking indoors and TB control policies. We aimed to establish the association between SHS and the risk of acquiring and worsening of TB in non-smokers. We identified 428 articles in the initial search and 12 comparative epidemiological studies met our inclusion criteria. Exposure to SHS was found to have a higher risk of TB infection [risk ratio (RR) 1·19, 95% confidence interval (CI) 0·90–1·57] compared to non-exposure; however, this did not reach statistical significance. There was marked variability (I 2 = 74%, P = 0·0008) between studies’ results, which could be explained by the differences in the diagnostic criteria used. Exposure to SHS was found to be statistically significantly associated (RR 1·59, 95% CI 1·11–2·27) with the risk of TB disease. There was significant heterogeneity (I 2 = 77%, P = 0·0006) between studies’ results, which was sourced to the internal characteristics of the studies rather than combining different study designs. We did not find any studies for SHS and TB treatment-related outcomes. Thus, we conclude that SHS exposure may increase the risk of acquiring TB infection and progression to TB disease; however, the evidence remains scanty and weak.

An analysis was undertaken to measure age-specific vaccine effectiveness (VE) of 2010/11 trivalent seasonal influenza vaccine (TIV) and monovalent 2009 pandemic influenza vaccine (PIV) administered in 2009/2010. The test-negative case-control study design was employed based on patients consulting primary care. Overall TIV effectiveness, adjusted for age and month, against confirmed influenza A(H1N1)pdm 2009 infection was 56% (95% CI 42–66); age-specific adjusted VE was 87% (95% CI 45–97) in <5-year-olds and 84% (95% CI 27–97) in 5- to 14-year-olds. Adjusted VE for PIV was only 28% (95% CI −6 to 51) overall and 72% (95% CI 15–91) in <5-year-olds. For confirmed influenza B infection, TIV effectiveness was 57% (95% CI 42–68) and in 5- to 14-year-olds 75% (95% CI 32–91). TIV provided moderate protection against the main circulating strains in 2010/2011, with higher protection in children. PIV administered during the previous season provided residual protection after 1 year, particularly in the <5 years age group.

Linear electrostatic waves in a magnetized four-component, two-temperature electron–positron plasma are investigated, with the hot species having the Boltzmann density distribution and the dynamics of cooler species governed by fluid equations with finite temperatures. A linear dispersion relation for electrostatic waves is derived for the model and analyzed for different wave modes. Analysis of the dispersion relation for perpendicular wave propagation yields a cyclotron mode with contributions from both cooler and hot species, which in the absence of hot species goes over to the upper hybrid mode of cooler species. For parallel propagation, both electron-acoustic and electron plasma modes are obtained, whereas for a single-temperature electron–positron plasma, only electron plasma mode can exist. Dispersion characteristics of these modes at different propagation angles are studied numerically.

The existence of large amplitude solitary waves in a plasma comprised of a cold negative dust fluid, adiabatic positive dust fluid, Boltzmann electrons and non-thermal ions is theoretically investigated. Different regions in parameter space that correspond to different values of the ratio of the charge-to-mass ratios of the positive and negative dust grains have been identified where either negative or positive potential solitary wave structures occur and a region where coexistence of negative and positive potential solitary waves is supported.

Fourteen strains of S. Typhi (n=13) and S. Paratyphi A (n=1) resistant to ciprofloxacin were compared with 30 ciprofloxacin decreased-susceptibility strains on the basis of qnr plasmid analysis, and nucleotide substitutions at gyrA, gyrB, parC and parE. In ciprofloxacin-resistant strains, five S. Typhi and a single S. Paratyphi A showed triple mutations in gyrA (Ser83→Phe, Asp87→Asn, Glu133→Gly) and a novel mutation outside the quinolone resistance determining region (QRDR) (Met52→Leu). Novel mutations were also discovered in an isolate (minimum inhibitory concentration 8 μg/ml) in gyrA gene Asp76→Asn and outside the QRDR Leu44→Ile. Out of 30 isolates with reduced susceptibility, single mutation was found in 12 strains only. Genes encoding qnr plasmid (qnr A, qnr B, AAC1-F) were not detected in ciprofloxacin-resistant or decreased-susceptibility strains. Antimicrobial surveillance coupled with molecular analysis of fluoroquinolone resistance is warranted for reconfirming novel and established molecular patterns of resistance, which is quintessential for reappraisal of enteric fever therapeutics.

The nonlinear propagation of the dust-acoustic wave is investigated in a weakly non-ideal plasma comprising Boltzmann electrons, non-thermal ions characterized by a non-thermal parameter α and a negatively charged dust fluid. The non-ideal dust fluid is represented by the van der Waals equation of state. Arbitrary amplitude soliton solutions are found to occur for both supersonic and subsonic values of the Mach number. Upper and lower limits of the range of values of α for which solitons exist are examined as a function of the non-ideal parameters associated with the effects of volume reduction and the cohesive forces, for both the supersonic and subsonic cases.

The existence of large-amplitude dust-acoustic double layers is investigated in an unmagnetized dusty plasma comprising a negatively charged warm dust fluid, non-thermal ions and Boltzmann electrons. It is found that the non-thermal plasma supports the existence of rarefactive double layers only. The dependence of the double-layer amplitude and Mach number on various parameters such as the non-thermal parameter, dust temperature and electron concentration is numerically examined.

The existence of arbitrary amplitude nonlinear electrostatic waves is investigated for a plasma with positively charged dust in the presence of two-temperature electron species. It is shown that such a plasma supports both soliton and double layer structures.

The influence of non-thermal ions on linear dust-acoustic waves is studied in an unmagnetized plasma consisting of ions which have a non-thermal velocity distribution, Boltzmann-distributed electrons and streaming dust particles. A detailed examination is conducted of the dependence of the real frequency and growth rate of the excited instability on the dust drift speed, temperature, particle densities and the parameter $\alpha$ that determines the non-thermal nature of the energetic ions. Comparisons with approximate analytical solutions are also made.

Non-thermal ion distributions are a characteristic feature of space plasmas, and in the current work the influence of such non-thermal ion distributions on the Jeans instability is examined. Following previous general models, the electrons are taken to be Boltzmann on the timescales involved, whilst the negative dust component is modelled by the continuity and momentum equations. The ion dynamics are described via a non-thermal Cairns distribution. The linear dispersion relation is derived and analysed for varying degrees of deviation from ordinary thermal behaviour, determined by the characteristic parameter of the Cairns distribution.

The four authors present their speculations about the future developments of mathematical logic in the twenty-first century. The areas of recursion theory, proof theory and logic for computer science, model theory, and set theory are discussed independently.