127 research outputs found

    Real-world wayfinding experiments: Individual preferences, decisions and the space syntax approach at street corners

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    This thesis investigates the role of spatial configuration on individual spatial decision-making. Over 100 participants take part in laboratory wayfinding experiments based on real-world images of street corners, using fixed and mobile eye trackers. Participants are asked to perform directed and undirected spatial tasks; stimulus-derived and task-related viewing patterns are accounted for. Responses to the spatial tasks are tested for task-related bias against responses in non-spatial tasks (recall, free viewing, and controlled search).   The evidence reveals that, during wayfinding, participants choose the more connected street, measurable with space syntax variables of relative street connectivity. Four space syntax variables are used: integration and choice at global and local scales. The resulting measure allows decisions made by individuals to be related directly to the space syntax analysis of spatial morphology. The fixation data allows for an investigation of how wayfinding choices and gaze bias may be linked. Viewing behaviour during the spatial tasks reveals areas of particular interest at each path alternative; these correspond to structural information in the built environment. A measure for identifying the location of such areas is proposed: "choice zones'". Choice zones are computed algorithmically, and are based on space-geometric measures visible in the scene. Choice zones offer a greater scope than existing measures because they are based on information visible in the real world; it is therefore possible to compute choice zones for images of different reference classes (eg. those with varying horizon or sky lines). The resulting measure has important implications for optimal routing and urban design, identifying those areas of the visual field that contain the most relevant environmental information pertaining to wayfinding

    In-situ growth of nonstoichiometric CrO0.87 and Co3O4 hybrid system for the enhanced electrocatalytic water splitting in alkaline media

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    The development of electrocatalysts for electrochemical water splitting has received considerable attention in response to the growing demand for renewable energy sources and environmental concerns. In this study, a simple hydrothermal growth approach was developed for the in-situ growth of non-stoichiometric CrO0.87 and Co3O4 hybrid materials. It is apparent that the morphology of the prepared material shows a heterogeneous aggregate of irregularly shaped nanoparticles. Both CrO0.87 and Co3O4 have cubic crystal structures. Its chemical composition was governed by the presence of Co, Cr, and O as its main constituents. For understanding the role CrO0.87 plays in the half-cell oxygen evolution reaction (OER) in alkaline conditions, CrO0.87 was optimized into Co3O4 nanostructures. The hybrid material with the highest concentration of CrO0.87 was found to be highly efficient at driving OER reactions at 255 mV and 20 mA cm−2. The optimized material demonstrated excellent durability for 45 h and a Tafel slope of 56 mV dec−1. Several factors may explain the outstanding performance of CrO0.87 and Co3O4 hybrid materials, including multiple metallic oxidation states, tailored surface properties, fast charge transport, and surface defects. An alternative method is proposed for the preparation of new generations of electrocatalysts for the conversion and storage of energy

    Impact of malaria diagnostic choice on monitoring of Plasmodium falciparum prevalence estimates in the Democratic Republic of the Congo and relevance to control programs in high-burden countries

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    Malaria programs rely upon a variety of diagnostic assays, including rapid diagnostic tests (RDTs), microscopy, polymerase chain reaction (PCR), and bead-based immunoassays (BBA), to monitor malaria prevalence and support control and elimination efforts. Data comparing these assays are limited, especially from high-burden countries like the Democratic Republic of the Congo (DRC). Using cross-sectional and routine data, we compared diagnostic performance and Plasmodium falciparum prevalence estimates across health areas of varying transmission intensity to illustrate the relevance of assay performance to malaria control programs. Data and samples were collected between March–June 2018 during a cross-sectional household survey across three health areas with low, moderate, and high transmission intensities within Kinshasa Province, DRC. Samples from 1,431 participants were evaluated using RDT, microscopy, PCR, and BBA. P. falciparum parasite prevalence varied between diagnostic methods across all health areas, with the highest prevalence estimates observed in Bu (57.4–72.4% across assays), followed by Kimpoko (32.6–53.2%), and Voix du Peuple (3.1–8.4%). Using latent class analysis to compare these diagnostic methods against an “alloyed gold standard,” the most sensitive diagnostic method was BBA in Bu (high prevalence) and Voix du Peuple (low prevalence), while PCR diagnosis was most sensitive in Kimpoko (moderate prevalence). RDTs were consistently the most specific diagnostic method in all health areas. Among 9.0 million people residing in Kinshasa Province in 2018, the estimated P. falciparum prevalence by microscopy, PCR, and BBA were nearly double that of RDT. Comparison of malaria RDT, microscopy, PCR, and BBA results confirmed differences in sensitivity and specificity that varied by endemicity, with PCR and BBA performing best for detecting any P. falciparum infection. Prevalence estimates varied widely depending on assay type for parasite detection. Inherent differences in assay performance should be carefully considered when using community survey and surveillance data to guide policy decisions

    Hippocampal and prefrontal processing of network topology to simulate the future

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    Topological networks lie at the heart of our cities and social milieu. However, it remains unclear how and when the brain processes topological structures to guide future behaviour during everyday life. Using fMRI in humans and a simulation of London (UK), here we show that, specifically when new streets are entered during navigation of the city, right posterior hippocampal activity indexes the change in the number of local topological connections available for future travel and right anterior hippocampal activity reflects global properties of the street entered. When forced detours require re-planning of the route to the goal, bilateral inferior lateral prefrontal activity scales with the planning demands of a breadth-first search of future paths. These results help shape models of how hippocampal and prefrontal regions support navigation, planning and future simulation

    Diagnosis and management of gastroesophageal reflux disease

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    Gastroesophageal reflux disease (GERD) is probably one of the most prevalent diseases in the world that also compromises the quality of life of the affected significantly. Its incidence in Brazil is 12%, corresponding to 20 million individuals. OBJECTIVE: To update the GERD management and the new trends on diagnosis and treatment, reviewing the international and Brazilian experience on it. METHOD: The literature review was based on papers published on Medline/Pubmed, SciELO, Lilacs, Embase and Cochrane crossing the following headings: gastroesophageal reflux disease, diagnosis, clinical treatment, surgery, fundoplication. RESULTS: Various factors are involved on GERD physiopathology, the most important being the transient lower esophageal sphincter relaxation. Clinical manifestations are heartburn, regurgitation (typical symptoms), cough, chest pain, asthma, hoarseness and throat clearing (atypical symptoms), which may be followed or not by typical symptoms. GERD patients may present complications such as peptic stenosis, hemorrhage, and Barrett's esophagus, which is the most important predisposing factor to adenocarcinoma. The GERD diagnosis must be based on the anamnesis and the symptoms must be evaluated in terms of duration, intensity, frequency, triggering and relief factors, pattern of evolution and impact on the patient's quality of life. The diagnosis requires confirmation with different exams. The goal of the clinical treatment is to relieve the symptoms and surgical treatment is indicated for patients who require continued drug use, with intolerance to prolonged clinical treatment and with GERD complications. CONCLUSION: GERD is a major digestive health problem and affect 12% of Brazilian people. The anamnesis is fundamental for the diagnosis of GERD, with special analysis of the typical and atypical symptoms (duration, intensity, frequency, triggering and relief factors, evolution and impact on the life quality). High digestive endoscopy and esophageal pHmetry are the most sensitive diagnosctic methods. The clinical treatment is useful in controlling the symptoms; however, the great problem is keeping the patients asymptomatic over time. Surgical treatment is indicated for patients who required continued drug use, intolerant to the drugs and with complicated forms of GERD.A doença do refluxo gastroesofágico (DRGE) é, provavelmente, uma das doenças mais prevalentes no mundo que compromete significativamente a qualidade de vida. Sua incidência no Brasil é de 12%, o que corresponde a 20 milhões de indivíduos. OBJETIVO: Atualizar o manuseio da DRGE e as novas tendências no diagnóstico e tratamento, revendo as experiências internacional e brasileira sobre o tema. MÉTODO: Foi realizada revisão da literatura baseada em artigos publicados no Medline/Pubmed, SciELO, Lilacs, Embase e Cochrane cruzando os seguintes descritores: doença do refluxo gastroesofágico, diagnóstico, tratamento clínico, cirurgia, fundoplicatura. RESULTADOS: Vários fatores estão envolvidos na fisiopatologia da DRGE, sendo o mais importante o relaxamento transitório do esfíncter inferior do esôfago. As manifestações clínicas são azia, regurgitação (sintomas típicos), tosse, dor torácica, asma, rouquidão e pigarro (sintomas atípicos), que podem ser seguidos ou não de sintomas típicos. Pacientes com DRGE podem apresentar complicações como estenose péptica, hemorragia e esôfago de Barrett, que é o fator predisponente mais importante para adenocarcinoma. O diagnóstico deve ser baseado na anamnese e os sintomas devem ser avaliados em termos de duração, intensidade, frequência, fatores precipitantes e relevância, padrão de evolução e impacto na qualidade de vida do paciente. O diagnóstico exige confirmação com exames diferentes. O objetivo do tratamento clínico é aliviar os sintomas e o tratamento cirúrgico é indicado para os que necessitam de uso contínuo de drogas, com intolerância ao tratamento clínico prolongado e com complicações. CONCLUSÃO: A anamnese é fundamental para o diagnóstico de DRGE, com análise especial dos sintomas típicos e atípicos. Endoscopia digestiva alta e pHmetria esofágica são os métodos diagnósticos mais sensíveis. O tratamento clínico é útil no controle dos sintomas; no entanto, o grande problema é manter os pacientes assintomáticos ao longo do tempo. O tratamento cirúrgico é indicado para pacientes que necessitaram o uso contínuo de drogas, intolerantes às drogas e com formas complicadas da DRGE.Universidade Estadual Paulista Júlio de Mesquita Filho, Departamento de Cirurgia e Ortopedia, Faculdade de Medicina de Botucatu, Botucatu, Anexo Verde, Rubião Junior s/n, CEP 18605-970, SP, BrasilUniversidade Estadual Paulista Júlio de Mesquita Filho, Departamento de Cirurgia e Ortopedia, Faculdade de Medicina de Botucatu, Botucatu, Anexo Verde, Rubião Junior s/n, CEP 18605-970, SP, Brasi
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