694 research outputs found

    Lateralization of face processing in the human brain

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    Are visual face processing mechanisms the same in the left and right cerebral hemispheres? The possibility of such ‘duplicated processing’ seems puzzling in terms of neural resource usage, and we currently lack a precise characterization of the lateral differences in face processing. To address this need, we have undertaken a three-pronged approach. Using functional magnetic resonance imaging, we assessed cortical sensitivity to facial semblance, the modulatory effects of context and temporal response dynamics. Results on all three fronts revealed systematic hemispheric differences. We found that: (i) activation patterns in the left fusiform gyrus correlate with image-level face-semblance, while those in the right correlate with categorical face/non-face judgements. (ii) Context exerts significant excitatory/inhibitory influence in the left, but has limited effect on the right. (iii) Face-selectivity persists in the right even after activity on the left has returned to baseline. These results provide important clues regarding the functional architecture of face processing, suggesting that the left hemisphere is involved in processing ‘low-level’ face semblance, and perhaps is a precursor to categorical ‘deep’ analyses on the right.John Merck FundSimons FoundationJames S. McDonnell FoundationNational Eye Institute (NIH, grant number R21-EY015521

    A Match in Time Saves Nine: Deterministic Online Matching With Delays

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    We consider the problem of online Min-cost Perfect Matching with Delays (MPMD) introduced by Emek et al. (STOC 2016). In this problem, an even number of requests appear in a metric space at different times and the goal of an online algorithm is to match them in pairs. In contrast to traditional online matching problems, in MPMD all requests appear online and an algorithm can match any pair of requests, but such decision may be delayed (e.g., to find a better match). The cost is the sum of matching distances and the introduced delays. We present the first deterministic online algorithm for this problem. Its competitive ratio is O(mlog25.5)O(m^{\log_2 5.5}) =O(m2.46) = O(m^{2.46}), where 2m2 m is the number of requests. This is polynomial in the number of metric space points if all requests are given at different points. In particular, the bound does not depend on other parameters of the metric, such as its aspect ratio. Unlike previous (randomized) solutions for the MPMD problem, our algorithm does not need to know the metric space in advance

    Effects of age, gender and soil-transmitted helminth infection on prevalence of Plasmodium infection among population living in bata district, equatorial Guinea

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    INTRODUCTION: Malaria and soil-transmitted helminth (STH) co-infection is an important parasitic infection affecting populations in co-endemic countries including Equatorial Guinea. To date, the health impact of STH and malaria co-infection is inconclusive. The current study aimed to report the malaria and STH infection epidemiology in the continental region of Equatorial Guinea. METHODS: We performed a cross-sectional study between October 2020 and January 2021 in the Bata district of Equatorial Guinea. Participants aged 1-9 years, 10-17 years and above 18 were recruited. Fresh venous blood was collected for malaria testing via mRDTs and light microscopy. Stool specimens were collected, and the Kato-Katz technique was used to detect the presence of Ascaris lumbricoides, Trichuris trichiura, hookworm spp. and intestinal Schistosoma eggs. RESULTS: A total of 402 participants were included in this study. An amount of 44.3% of them lived in urban areas, and only 51.9% of them reported having bed nets. Malaria infections were detected in 34.8% of the participants, while 50% of malaria infections were reported in children aged 10-17 years. Females had a lower prevalence of malaria (28.8%) compared with males (41.7%). Children of 1-9 years carried more gametocytes compared with other age groups. An amount of 49.3% of the participants infected with T. trichiura had malaria parasites compared with those infected with A. lumbricoides (39.6%) or both (46.8%). CONCLUSIONS: The overlapping problem of STH and malaria is neglected in Bata. The current study forces the government and other stakeholders involved in the fight against malaria and STH to consider a combined control program strategy for both parasitic infections in Equatorial Guinea

    Learned helplessness in chess players: The importance of task similarity and the role of skill

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    The effects of noncontingency between subjects' responses and outcomes were examined with respect to treatment/posttest similarity and skill in the task. The experimental design consisted of three groups. The first group had to solve chess problems with objective solutions and received veridical feedback; each member of the second group faced problems with no objective solutions, and received the same feedback as the member of the first group he was yoked with, but without any control on it; the control group received a waiting task. It was found that the group with unsolvable problems was more depressed than the two other groups at the end of the experiment. The mid-strength players were the most sensitive to the manipulation, and the weakest players showed little effect of learned helplessness. It was also found that the effects were proportional to the degree of similarity between the treatment and the posttest. The results limit the domain of applicability of the learned helplessness model

    Exploring local knowledge and perceptions on zoonoses among pastoralists in northern and eastern Tanzania

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    Background: Zoonoses account for the most commonly reported emerging and re-emerging infectious diseases in Sub-Saharan Africa. However, there is limited knowledge on how pastoral communities perceive zoonoses in relation to their livelihoods, culture and their wider ecology. This study was carried out to explore local knowledge and perceptions on zoonoses among pastoralists in Tanzania. Methodology and principal findings: This study involved pastoralists in Ngorongoro district in northern Tanzania and Kibaha and Bagamoyo districts in eastern Tanzania. Qualitative methods of focus group discussions, participatory epidemiology and interviews were used. A total of 223 people were involved in the study. Among the pastoralists, there was no specific term in their local language that describes zoonosis. Pastoralists from northern Tanzania possessed a higher understanding on the existence of a number of zoonoses than their eastern districts' counterparts. Understanding of zoonoses could be categorized into two broad groups: a local syndromic framework, whereby specific symptoms of a particular illness in humans concurred with symptoms in animals, and the biomedical framework, where a case definition is supported by diagnostic tests. Some pastoralists understand the possibility of some infections that could cross over to humans from animals but harm from these are generally tolerated and are not considered as threats. A number of social and cultural practices aimed at maintaining specific cultural functions including social cohesion and rites of passage involve animal products, which present zoonotic risk. Conclusions: These findings show how zoonoses are locally understood, and how epidemiology and biomedicine are shaping pastoralists perceptions to zoonoses. Evidence is needed to understand better the true burden and impact of zoonoses in these communities. More studies are needed that seek to clarify the common understanding of zoonoses that could be used to guide effective and locally relevant interventions. Such studies should consider in their approaches the pastoralists' wider social, cultural and economic set up

    Cause-of-Death Contributions to Educational Inequalities in Mortality in Austria between 1981/1982 and 1991/1992: Les contributions des causes de décès aux inégalités de mortalité par niveau d’éducation en Autriche entre 1981/1982 et 1991/1992

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    This article uses census records and deaths records to analyze trends in educational inequalities in mortality for Austrian women and men aged 35–64 years between 1981/1982 and 1991/1992. We find an increasing gradient in mortality by education for circulatory diseases and especially ischaemic heart disease. Respiratory diseases and, in addition for women, cancers showed the opposite trend. Using decomposition analysis, we give evidence that in many cases changes in the age-structure within the 10-year interval had a bigger effect than direct improvements in mortality on the analyzed subpopulations

    Doing implementation research on health governance: a frontline researcher’s reflexive account of field-level challenges and their management

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    BACKGROUND: Implementation Research (IR) in and around health systems comes with unique challenges for researchers including implementation, multi-layer governance, and ethical issues. Partnerships between researchers, implementers, policy makers and community members are central to IR and come with additional challenges. In this paper, we elaborate on the challenges faced by frontline field researchers, drawing from experience with an IR study on Village Health Sanitation and Nutrition Committees (VHSNCs). METHODS: The IR on VHSNC took place in one state/province in India over an 18-month research period. The IR study had twin components; intervention and in-depth research. The intervention sought to strengthen the VHSNC functioning, and concurrently the research arm sought to understand the contextual factors, pathways and mechanism affecting VHSNC functions. Frontline researchers were employed for data collection and a research assistant was living in the study sites. The frontline research assistant experienced a range of challenges, while collecting data from the study sites, which were documented as field memos and analysed using inductive content analysis approach. RESULTS: Due to the relational nature of IR, the challenges coalesced around two sets of relationships (a) between the community and frontline researchers and (b) between implementers and frontline researchers. In the community, the frontline researcher was viewed as the supervisor of the intervention and was perceived by the community to have power to bring about beneficial changes with public services and facilities. Implementers expected help from the frontline researcher in problem-solving in VHSNCs, and feedback on community mobilization to improve their approaches. A concerted effort was undertaken by the whole research team to clarify and dispel concerns among the community and implementers through careful and constant communication. The strategies employed were both managerial, relational and reflexive in nature. CONCLUSION: Frontline researchers through their experiences shape the research process and its outcome and they play a central role in the research. It demonstrates that frontline researcher resilience is very crucial when conducting health policy and systems research.Scopu

    A general co-expression network-based approach to gene expression analysis: comparison and applications

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    <p>Abstract</p> <p>Background</p> <p>Co-expression network-based approaches have become popular in analyzing microarray data, such as for detecting functional gene modules. However, co-expression networks are often constructed by ad hoc methods, and network-based analyses have not been shown to outperform the conventional cluster analyses, partially due to the lack of an unbiased evaluation metric.</p> <p>Results</p> <p>Here, we develop a general co-expression network-based approach for analyzing both genes and samples in microarray data. Our approach consists of a simple but robust rank-based network construction method, a parameter-free module discovery algorithm and a novel reference network-based metric for module evaluation. We report some interesting topological properties of rank-based co-expression networks that are very different from that of value-based networks in the literature. Using a large set of synthetic and real microarray data, we demonstrate the superior performance of our approach over several popular existing algorithms. Applications of our approach to yeast, Arabidopsis and human cancer microarray data reveal many interesting modules, including a fatal subtype of lymphoma and a gene module regulating yeast telomere integrity, which were missed by the existing methods.</p> <p>Conclusions</p> <p>We demonstrated that our novel approach is very effective in discovering the modular structures in microarray data, both for genes and for samples. As the method is essentially parameter-free, it may be applied to large data sets where the number of clusters is difficult to estimate. The method is also very general and can be applied to other types of data. A MATLAB implementation of our algorithm can be downloaded from <url>http://cs.utsa.edu/~jruan/Software.html</url>.</p
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