A cross-sectional study on factors associated with health seeking behaviour of Malawians aged 15+ years in 2016

IntroductionHealth seeking behaviour (HSB) refers to actions taken by individuals who are ill in order to find appropriate remedy. Most studies on HSB have only examined one symptom or covered only a specific geographical location within a country. In this study, we used a representative sample of adults to explore the factors associated with HSB in response to 30 symptoms reported by adult Malawians in 2016.MethodsWe used the 2016 Malawi Integrated Household Survey dataset. We fitted a multilevel logistic regression model of likelihood of ‘seeking care at a health facility’ using a forward step-wise selection method, with age, sex and reported symptoms entered as a priori variables. We calculated the odds ratios (ORs) and their associated 95% confidence intervals (95% CI). We set the level of statistical significance at P < 0.05.ResultsOf 6909 adults included in the survey, 1907 (29%) reported symptoms during the 2 weeks preceding the survey. Of these, 937 (57%) sought care at a health facility. Adults in urban areas were more likely to seek health care at a health facility than those in rural areas (AOR = 1.65, 95% CI: 1.19–2.30, P = 0.003). Females had a higher likelihood of seeking care from health facilities than males (AOR = 1.26, 95% CI: 1.03–1.59, P = 0.029). Being of higher wealth status was associated with a higher likelihood of seeking care from a health facility (AOR = 1.58, 95% CI: 1.16–2.16, P = 0.004). Having fever and eye problems were associated with higher likelihood of seeking care at a health facility, while having headache, stomach ache and respiratory tract infections were associated with lower likelihood of seeking care at a health facility.ConclusionThis study has shown that there is a need to understand and address individual, socioeconomic and geographical barriers to health seeking to increase access and appropriate use of health care and fast-track progress towards Universal Health Coverage among the adult population.     

From the Cover: Species interactions and the structure of complex communication networks

A universal challenge faced by animal species is the need to communicate effectively against a backdrop of heterospecific signals. It is often assumed that this need results in signal divergence to minimize interference among community members, yet previous support for this idea is mixed, and few studies have tested the opposing hypothesis that interactions among competing species promote widespread convergence in signaling regimes. Using a null model approach to analyze acoustic signaling in 307 species of Amazonian birds, we show that closely related lineages signal together in time and space and that acoustic signals given in temporal or spatial proximity are more similar in design than expected by chance. These results challenge the view that multispecies choruses are structured by temporal, spatial, or acoustic partitioning and instead suggest that social communication between competing species can fundamentally organize signaling assemblages, leading to the opposite pattern of clustering in signals and signaling behavior.One of the core principles of animal communication is that signals should be detectable and convey an accurate message against a noisy background (1–3). This background can involve direct overlap of sounds, as in the case of masking by simultaneous signals (4, 5), or simply the co-occurrence of different species using confusingly similar signals at the same location (6–8). As most animals communicate within assemblages of related species, the problem of signal interference is widespread and may have far-reaching implications for the evolution of signals and signaling behavior. This concept—variously termed the “noisy neighbors” hypothesis (9) or “cocktail party problem” (10)—has attracted much attention over recent years. However, the extent to which it provides a general explanation for patterns of signaling in animal communities remains contentious (6, 8).The traditional view is that the signaling strategies of animals are shaped by limiting similarity among competitors, much as competition for ecological resources is thought to promote partitioning of niche space (11–13). Partitioning of signal space may occur if species compete for position near overcrowded transmission optima, and, concurrently, if overlap in signal design impairs the detection or discrimination of signals mediating mate choice and resource competition (14). Under these conditions, mechanisms of selection against misdirected aggression (e.g., character displacement) or the production of unfit hybrids (e.g., reinforcement) are predicted to drive phenotypic divergence (9), whereas similar mechanisms may lead to related species signaling at different times or in different locations (13). These pathways theoretically lead to structural, temporal, and spatial partitioning of signals and signalers in animal assemblages, but tests of these patterns have produced mixed results (6, 11, 15).A contrasting possibility is that selection for signal divergence is weak and that co-occurring species instead show the opposite pattern of signal clustering (16). One potential driver of this pattern is that shared habitats can exert convergent selection on signals (17). Another is that signals often have dual function in mate attraction and resource defense (18), potentially mediating competition among closely related species for ecological resources (19). Thus, multispecies choruses may operate to some degree as extended communication networks, not only within species (20) but between species. The effect of such a network would be to increase the likelihood of interspecific communication involving closely related species with similar signals. A pattern of signal clustering caused by communication among similar congeners may be further exaggerated when competitive interactions among species promote signal similarity (16). This process may occur when individuals with convergent agonistic signals have higher fitness because they are better at defending resources against both conspecific and heterospecific competitors, driving convergent evolution (21, 22). Taken together, these alternative views suggest that the most pervasive effect of species interactions on animal communication systems may not be partitioning, as generally proposed, but synchrony and stereotypy among competing species.Progress in resolving these opposing viewpoints has been limited because most studies of signaling assemblages have compiled lists of species co-occurring at particular localities and then compared multiple assemblages across regional scales (6, 15). This approach may be misleading because of spatial biases in phylogenetic relationships and habitat. On the one hand, sympatric species tend to be significantly older than allopatric species, at least within radiations (23, 24), and thus the signals of co-occurring lineages may be more divergent than expected by chance simply because they have had more time to diverge, exaggerating the evidence for partitioning. Conversely, species co-occurring at local scales may be less divergent because they are segregated by habitat across a study site and therefore are unlikely to signal together. Although some studies (7, 11) partially overcome these issues by sampling assemblages from single points in space, none has considered the effects of habitat and the potential role of competitive interactions among related species (16). Moreover, previous studies have generally assessed partitioning in relatively small assemblages (<30 species), reducing both the likelihood of competition over transmission optima and the power of statistical tests.Here, we sample >90 signaling assemblages (Fig. S1) containing a combined total of >300 species (Dataset S1) to assess the role of species interactions in structuring and organizing the dawn chorus of Amazonian rainforest birds. Each assemblage comprised species producing acoustic signals, identified from standardized 120-min sound recordings taken at points distributed across a single study locality. We also restricted analyses to 10-min time blocks and assumed that assemblages of species signaling in these blocks were forced to discriminate among each other (i.e., they were each other’s background noise) and also that they had an increased likelihood of signaling simultaneously (i.e., directly masking each other’s signals). We use the term cosignaling to describe pairs of species signaling during the same 10- or 120-min time block and thus not necessarily signaling simultaneously. We coded all assemblages for habitat and time of day, calculated the acoustic similarity of cosignaling species using spectrographic analyses of voice recordings, and estimated the evolutionary relatedness of cosignaling species using a hierarchical taxonomic framework.Our null hypothesis states that species interactions have no effect on chorus structure and thus that species with similar signals are randomly distributed in space and time (Fig. 1A). The distance between signals in observed choruses should not differ significantly from that expected by chance, accounting for habitat and evolutionary relationships. We envisage two scenarios that may falsify the null. The partitioning hypothesis predicts that signal design is evenly spaced across communities, with a larger distance between co-occurring signals than predicted by chance (Fig. 1B). The network hypothesis predicts that competing species interact using phylogenetically conserved signals and thus that signals are clustered in distribution, with a smaller distance between co-occurring signals than predicted by chance (Fig. 1C). The partitioning and network hypotheses involve different forms of species interaction with opposing effects on chorus structure. Although we do not measure species interactions directly, we follow standard approaches in assuming that such interactions predict patterns in the trait structure of assemblages (25).Open in a separate windowFig. 1.Predictions of three hypotheses proposed to structure multispecies choruses, illustrated using hypothetical seven-species choruses with signal design plotted in multivariate signaling space. The null hypothesis that species interactions have no effect predicts that signal structure is random (A), generating an intermediate mean nearest-neighbor distance d. The partitioning hypothesis predicts an evenly spaced signal structure (B) reflected in larger values for d. The network hypothesis predicts that related species will signal together, causing signals to be clustered around optima (C), and generating small values for d. We test these predictions by assessing whether d, viewed across a sample of communities, is higher or lower than expected by chance. We calculated d in two ways: d₁ (Upper) is the mean nearest neighbor distance [nnd] across all community members; and d₂ (Lower) is the mean nnd across the three pairs of species with most similar signals.Our aims were to (i) quantify acoustic properties of signals transmitted in the dawn chorus; (ii) estimate the degree of signal similarity among cosignaling species; and (iii) compare the observed distribution of signal properties with that expected by chance. We also consider spatial explanations for chorus structure, including the reduced cosignaling of species with similar signals through spatial partitioning. This form of segregation may occur because ecological competition is elevated in tropical bird communities (26), causing parapatric (27) or “checkerboard” distributions (28) among closely related species, thus potentially leading to apparent signal partitioning by competitive exclusion. The network hypothesis predicts the opposite pattern as closely related species should synchronize their signaling activity using shared territorial signals. We test these predictions by comparing 120-min (spatially segregated) and 10-min (nonsegregated) choruses and using taxonomic relatedness to estimate the degree of cosignaling between close relatives.The Amazonian dawn chorus provides one of the world’s most diverse multispecies signaling assemblages and an ideal system for exploring the effects of competition on signaling strategies for three reasons. First, visibility is hampered by dense vegetation, and thus long-distance signaling is forced into one modality (acoustic communication). Second, background noise levels are extremely high as a result of other organisms, including insects, amphibians, and primates, suggesting that selection for partitioning of acoustic signals should be maximized (12). Finally, many tropical species are permanently resident and apparently interspecifically territorial, using acoustic signals to mediate competitive interactions with heterospecifics (18, 26, 29). In combination, these factors imply that large numbers of species compete both for ecological resources and a narrow window of optimal signaling space (7, 30), providing a context in which to test the relative importance of acoustic partitioning and interspecific communication networks.     

Adverse events and deterioration reported by participants in the PACE trial of therapies for chronic fatigue syndrome

Objective

Adverse events (AEs) are health related events, reported by participants in clinical trials. We describe AEs in the PACE trial of treatments for chronic fatigue syndrome (CFS) and baseline characteristics associated with them.

Methods

AEs were recorded on three occasions over one year in 641 participants. We compared the numbers and nature of AEs between treatment arms of specialist medical care (SMC) alone, or SMC supplemented by adaptive pacing therapy (APT), cognitive behaviour therapy (CBT) or graded exercise therapy (GET). We examined associations with baseline measures by binary logistic regression analyses, and compared the proportions of participants who deteriorated by clinically important amounts.

Results

Serious adverse events and reactions were infrequent. Non-serious adverse events were common; the median (quartiles) number was 4 (2, 8) per participant, with no significant differences between treatments (P = .47). A greater number of NSAEs were associated with recruitment centre, and baseline physical symptom count, body mass index, and depressive disorder. Physical function deteriorated in 39 (25%) participants after APT, 15 (9%) after CBT, 18 (11%) after GET, and 28 (18%) after SMC (P < .001), with no significant differences in worsening fatigue.

Conclusions

The numbers of adverse events did not differ significantly between trial treatments, but physical deterioration occurred most often after APT. The reporting of non-serious adverse events may reflect the nature of the illness rather than the effect of treatments. Differences between centres suggest that both standardisation of ascertainment methods and training are important when collecting adverse event data.     

Vanilloid-like agents inhibit aggregation of human platelets

Introduction

Plant-derived and endogenous vanilloid-like agents exert their effects on cells through transient receptor potential vanilloid-1 (TRPV1). Little is known about the effects of these agents on platelet aggregation. We investigated the effect of various vanilloid-like agents on in-vitro platelet aggregation and tested whether this action is mediated through TRPV1. Understanding the mechanism of action of these compounds in platelets is important in that these compounds may be developed as novel anti-platelet agents.

Materials and Methods

The effects of plant-derived (capsaicin; dihydrocapsaicin, DHC) and endogenous vanilloid-like agents (N-oleoyldopamine, OLDA; N-arachidonoyl-dopamine, NADA) on platelet aggregation were investigated using ADP (5, 10 μM), collagen (4, 8 μg/mL) and arachidonic acid (AA, 300, 400 μg/mL) as agonists. The direct effects of these agents on platelet viability were also determined using an LDH release assay.

Results

Capsaicin, OLDA and NADA inhibited ADP-induced platelet aggregation in a concentration-dependent manner. OLDA and NADA, but not capsaicin and DHC, inhibited collagen-induced aggregation, whereas AA-induced aggregation was inhibited by capsaicin, DHC and NADA, but not OLDA. Inhibition of aggregation was not due to direct toxicity of these agents towards platelets. The TRPV1 antagonist, SB-452533, did not affect inhibition of ADP-induced platelet aggregation by capsaicin and OLDA.

Conclusions

These results demonstrate that the endovanilloids, OLDA and NADA, and plant-derived vanilloid, capsaicin, inhibit ADP-induced platelet aggregation. Collagen-induced aggregation was inhibited only by endovanilloids, whereas AA-induced aggregation was inhibited by capsaicin, DHC and NADA. This inhibition was not due to direct toxic effects of these agents, nor was inhibition of ADP-induced aggregation TRPV1 mediated.     

Implementation of the Risk–Need–Responsivity Framework across the Juvenile Justice Agencies in Singapore

The Risk–Need–Responsivity (RNR) framework is regarded as the forefront of offender rehabilitation in guiding youth offender risk assessment and interventions. This article discusses the juvenile justice system in Singapore and the local research that has been conducted in relation to the RNR framework and the associated Youth Level of Service (YLS) measures. It describes a journey that saw the implementation of the RNR framework across the juvenile justice agencies and highlights the challenges that were faced during the implementation process on the ground. Finally, the article concludes by providing future directions for the implementation of the RNR framework in Singapore.