1,584 research outputs found
Parental investment and child health in a Yanomamö village suffering short-term food stress
The 1998 El Niño significantly reduced garden productivity in the
Upper Orinoco region in Venezuela. Consequently, parents were forced to
allocate food carefully to their children. Nutrition data collected from village
children combined with genealogical data allowed the determination of which
children suffered most, and whether the patterns of food distribution
accorded with predictions from parental investment theory. For boys, three
social variables accounted for over 70% of the variance in subcutaneous fat
after controlling for age: number of siblings, age of the mother’s youngest
child, and whether the mother was the senior or junior co-wife, or was
married monogamously. These results accord well with parental investment
theory. Parents experiencing food stress faced a trade-off between quantity
and quality, and between investing in younger versus older offspring. In
addition, boys with access to more paternal investment (i.e. no stepmother)
were better nourished. These variables did not account for any of the
variance in female nutrition. Girls’ nutrition was associated with the size of
their patrilineage and the number of non-relatives in the village, suggesting
that lineage politics may have played a role. An apparent lack of relationship
between orphan status and nutrition is also interesting, given that orphans
suffered high rates of skin flea infections. The large number of orphans being
cared for by only two grandparents suggests that grooming time may have
been the resource in short supply.
Introductio
Community-based control of a neglected tropical disease: the mossy foot treatment and prevention association
Podoconiosis (endemic non-filarial elephantiasis, also known as mossy foot) is a non-communicable disease now found exclusively in the tropics, caused by the conjunction of environmental, genetic, and economic factors. Silicate particles formed by the disintegration of lava in areas of high altitude (over 1,000 m) and seasonal rainfall (over 1,000 mm per annum) penetrate the skin of barefoot subsistence farmers, and in susceptible individuals cause lymphatic blockage and subsequent elephantiasis [1]. Although an estimated one million Ethiopians (of a total population of 77 million) are afflicted with podoconiosis [2], which creates a huge economic burden in endemic areas [3], no national policy has yet been developed to control or prevent the condition, and most affected communities remain unaware of treatment options
Local biases drive, but do not determine, the perception of illusory trajectories
When a dot moves horizontally across a set of tilted lines of alternating orientations, the dot appears to be moving up and down along its trajectory. This perceptual phenomenon, known as the slalom illusion, reveals a mismatch between the veridical motion signals and the subjective percept of the motion trajectory, which has not been comprehensively explained. In the present study, we investigated the empirical boundaries of the slalom illusion using psychophysical methods. The phenomenon was found to occur both under conditions of smooth pursuit eye movements and constant fixation, and to be consistently amplified by intermittently occluding the dot trajectory. When the motion direction of the dot was not constant, however, the stimulus display did not elicit the expected illusory percept. These findings confirm that a local bias towards perpendicularity at the intersection points between the dot trajectory and the tilted lines cause the illusion, but also highlight that higher-level cortical processes are involved in interpreting and amplifying the biased local motion signals into a global illusion of trajectory perception
The influence of semantic and phonological factors on syntactic decisions: An event-related brain potential study
During language production and comprehension, information about a word's syntactic properties is sometimes needed. While the decision about the grammatical gender of a word requires access to syntactic knowledge, it has also been hypothesized that semantic (i.e., biological gender) or phonological information (i.e., sound regularities) may influence this decision. Event-related potentials (ERPs) were measured while native speakers of German processed written words that were or were not semantically and/or phonologically marked for gender. Behavioral and ERP results showed that participants were faster in making a gender decision when words were semantically and/or phonologically gender marked than when this was not the case, although the phonological effects were less clear. In conclusion, our data provide evidence that even though participants performed a grammatical gender decision, this task can be influenced by semantic and phonological factors
Defining severe obstructive lung disease in the biologic era: an endotype-based approach.
Severe obstructive lung disease, which encompasses patients with asthma, chronic obstructive pulmonary disease (COPD) or features of both, remains a considerable global health problem and burden on healthcare resources. However, the clinical definitions of severe asthma and COPD do not reflect the heterogeneity within these diagnoses or the potential for overlap between them, which may lead to inappropriate treatment decisions. Furthermore, most studies exclude patients with diagnoses of both asthma and COPD. Clinical definitions can influence clinical trial design and are both influenced by, and influence, regulatory indications and treatment recommendations. Therefore, to ensure its relevance in the era of targeted biologic therapies, the definition of severe obstructive lung disease must be updated so that it includes all patients who could benefit from novel treatments and for whom associated costs are justified. Here, we review evolving clinical definitions of severe obstructive lung disease and evaluate how these have influenced trial design by summarising eligibility criteria and primary outcomes of phase III randomised controlled trials of biologic therapies. Based on our findings, we discuss the advantages of a phenotype- and endotype-based approach to select appropriate populations for future trials that may influence regulatory approvals and clinical practice, allowing targeted biologic therapies to benefit a greater proportion and range of patients. This calls for co-ordinated efforts between investigators, pharmaceutical developers and regulators to ensure biologic therapies reach their full potential in the management of severe obstructive lung disease
Local biases drive, but do not determine, the perception of illusory trajectories
When a dot moves horizontally across a set of tilted lines of alternating orientations, the dot appears to be moving up and down along its trajectory. This perceptual phenomenon, known as the slalom illusion, reveals a mismatch between the veridical motion signals and the subjective percept of the motion trajectory, which has not been comprehensively explained. In the present study, we investigated the empirical boundaries of the slalom illusion using psychophysical methods. The phenomenon was found to occur both under conditions of smooth pursuit eye movements and constant fixation, and to be consistently amplified by intermittently occluding the dot trajectory. When the motion direction of the dot was not constant, however, the stimulus display did not elicit the expected illusory percept. These findings confirm that a local bias towards perpendicularity at the intersection points between the dot trajectory and the tilted lines cause the illusion, but also highlight that higher-level cortical processes are involved in interpreting and amplifying the biased local motion signals into a global illusion of trajectory perception
Globally prevalent PfMDR1 mutations modulate Plasmodium falciparum susceptibility to artemisinin-based combination therapies
Antimalarial chemotherapy, globally reliant on artemisinin-based combination therapies (ACTs), is threatened by the spread of drug resistance in Plasmodium falciparum parasites. Here we use zinc-finger nucleases to genetically modify the multidrug resistance-1 transporter PfMDR1 at amino acids 86 and 184, and demonstrate that the widely prevalent N86Y mutation augments resistance to the ACT partner drug amodiaquine and the former first-line agent chloroquine. In contrast, N86Y increases parasite susceptibility to the partner drugs lumefantrine and mefloquine, and the active artemisinin metabolite dihydroartemisinin. The PfMDR1 N86 plus Y184F isoform moderately reduces piperaquine potency in strains expressing an Asian/African variant of the chloroquine resistance transporter PfCRT. Mutations in both digestive vacuole-resident transporters are thought to differentially regulate ACT drug interactions with host haem, a product of parasite-mediated haemoglobin degradation. Global mapping of these mutations illustrates where the different ACTs could be selectively deployed to optimize treatment based on regional differences in PfMDR1 haplotypes.This work was funded in part by the National Institutes of Health (R01 AI50234, AI124678 and AI109023) and a Burroughs Wellcome Fund Investigator in Pathogenesis of Infectious Diseases award to D.A.F. This research also received funding from the Portuguese Fundacao para a Ciencia e Tecnologia (FCT), cofunded by Programa Operacional Regional do Norte (ON.2-O Novo Norte); from the Quadro de Referencia Estrategico Nacional (QREN) through the Fundo Europeu de Desenvolvimento Regional (FEDER) and from the Projeto Estrategico - LA 26 - 2013-2014 (PEst-C/SAU/LA0026/2013). M.I.V. is the recipient of a postdoctoral fellowship from FCT/Ministerio da Ciencia e Ensino Superior, Portugal-MCES (SFRH/BPD/76614/2011). A.M.L. was supported by an Australian National Health and Medical Research Council (NHMRC) Overseas Biomedical Fellowship (585519). R.E.M. was supported by an NHMRC RD Wright Biomedical Fellowship (1053082). A.C.U. was supported by an Irving scholarship from Columbia University. We thank Dr Andrea Ecker for her help with plasmid design and Pedro Ferreira for his expert help with Fig. 6.info:eu-repo/semantics/publishedVersio
Height and timing of growth spurt during puberty in young people living with vertically acquired HIV in Europe and Thailand.
OBJECTIVE: The aim of this study was to describe growth during puberty in young people with vertically acquired HIV. DESIGN: Pooled data from 12 paediatric HIV cohorts in Europe and Thailand. METHODS: One thousand and ninety-four children initiating a nonnucleoside reverse transcriptase inhibitor or boosted protease inhibitor based regimen aged 1-10 years were included. Super Imposition by Translation And Rotation (SITAR) models described growth from age 8 years using three parameters (average height, timing and shape of the growth spurt), dependent on age and height-for-age z-score (HAZ) (WHO references) at antiretroviral therapy (ART) initiation. Multivariate regression explored characteristics associated with these three parameters. RESULTS: At ART initiation, median age and HAZ was 6.4 [interquartile range (IQR): 2.8, 9.0] years and -1.2 (IQR: -2.3 to -0.2), respectively. Median follow-up was 9.1 (IQR: 6.9, 11.4) years. In girls, older age and lower HAZ at ART initiation were independently associated with a growth spurt which occurred 0.41 (95% confidence interval 0.20-0.62) years later in children starting ART age 6 to 10 years compared with 1 to 2 years and 1.50 (1.21-1.78) years later in those starting with HAZ less than -3 compared with HAZ at least -1. Later growth spurts in girls resulted in continued height growth into later adolescence. In boys starting ART with HAZ less than -1, growth spurts were later in children starting ART in the oldest age group, but for HAZ at least -1, there was no association with age. Girls and boys who initiated ART with HAZ at least -1 maintained a similar height to the WHO reference mean. CONCLUSION: Stunting at ART initiation was associated with later growth spurts in girls. Children with HAZ at least -1 at ART initiation grew in height at the level expected in HIV negative children of a comparable age
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