450 research outputs found

    O dualismo filosófico e o lugar dos brancos conquistadores no pensamento ameríndio, segundo Claude Lévi-Strauss.

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    No presente artigo, mostro, inicialmente, a partir do desvelamento de certos pressupostos de Claude Lévi-Strauss a respeito do pensamento selvagem e do modo de operar do espírito humano, a maneira como, em A história de Lince (1991), o autor compreende a interpretação dos ameríndios em relação a chegada dos brancos conquistadores na América colonial. Em seguida, aponto de que modo essa chave de leitura ameríndia está relacionada ao princípio filosófico e ético-político do dualismo, o qual, segundo Levis-Strauss, está na base do pensamento dos povos indígenas das américas

    Morphologic analysis of developmental phases and gill ontogenesis in neotropical species Poecilia vivipara (Cyprinodontiformes: Poeciliidae) exposed to different salinities

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    The present study evaluated and characterized the different phases of development and the cell types present in the gill epithelium of embryos, larvae, and fingerlings of guppy (Poecilia vivipara Bloch & Schneider, 1801) specimens exposed to water with salinity ranging from 0 to 20 . The development of P. vivipara was classified into eight phases. The yolk was intensely eosinophilic, with glycidic and lipidic components between phases 1 to 7. After the development of their branchial epithelium, the presence of pavement cells, mitochondria-rich cells, and mucous cells (MCs) was observed. The understanding of ontogenesis indicates the sequence of cellular origin. Only type IV MCs located in the gill rays was detected from phase 3 through phase 7. Other types of MCs were observed only when the fingerlings were exposed to salinity changes and showed to be lectin-reactive, thus indicating that P. vivipara modulates the cellular behavior when submitted to salinity changes. Exposure to variable saline concentrations did not interfere in the initial development of guppies. The presence of a yolk sac until the fingerling phase characterized this species as ovoviviparous.55456

    Predicting the risk of future depression among school-attending adolescents in Nigeria using a model developed in Brazil

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    Depression commonly emerges in adolescence and is a major public health issue in low- and middle-income countries where 90% of the world's adolescents live. Thus efforts to prevent depression onset are crucial in countries like Nigeria, where two-thirds of the population are aged under 24. Therefore, we tested the ability of a prediction model developed in Brazil to predict future depression in a Nigerian adolescent sample. Data were obtained from school students aged 14–16 years in Lagos, who were assessed in 2016 and 2019 for depression using a self-completed version of the Mini International Neuropsychiatric Interview for Children and Adolescents. Only the 1,928 students free of depression at baseline were included. Penalized logistic regression was used to predict individualized risk of developing depression at follow-up for each adolescent based on the 7 matching baseline sociodemographic predictors from the Brazilian model. Discrimination between adolescents who did and did not develop depression was better than chance (area under the curve = 0.62 (bootstrap-corrected 95% CI: 0.58–0.66). However, the model was not well-calibrated even after adjustment of the intercept, indicating poorer overall performance compared to the original Brazilian cohort. Updating the model with context-specific factors may improve prediction of depression in this setting

    Autonomous Navigation System for a Delivery Drone

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    The use of delivery services is an increasing trend worldwide, further enhanced by the COVID pandemic. In this context, drone delivery systems are of great interest as they may allow for faster and cheaper deliveries. This paper presents a navigation system that makes feasible the delivery of parcels with autonomous drones. The system generates a path between a start and a final point and controls the drone to follow this path based on its localization obtained through GPS, 9DoF IMU, and barometer. In the landing phase, information of poses estimated by a marker (ArUco) detection technique using a camera, ultra-wideband (UWB) devices, and the drone's software estimation are merged by utilizing an Extended Kalman Filter algorithm to improve the landing precision. A vector field-based method controls the drone to follow the desired path smoothly, reducing vibrations or harsh movements that could harm the transported parcel. Real experiments validate the delivery strategy and allow to evaluate the performance of the adopted techniques. Preliminary results state the viability of our proposal for autonomous drone delivery.Comment: 12 pages, 15 figures, extended version of an paper published at the XXIII Brazilian Congress of Automatica, entitled "Desenvolvimento de um drone aut\^onomo para tarefas de entrega de carga

    Predicting the risk of depression among adolescents in Nepal using a model developed in Brazil : the IDEA Project

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    The burden of adolescent depression is high in low- and middle-income countries (LMICs), yet research into prevention is lacking. Development and validation of models to predict individualized risk of depression among adolescents in LMICs is rare but crucial to ensure appropriate targeting of preventive interventions. We assessed the ability of a model developed in Brazil, a middle-income country, to predict depression in an existing culturally different adolescent cohort from Nepal, a low-income country with a large youth population with high rates of depression. Data were utilized from the longitudinal study of 258 former child soldiers matched with 258 war-affected civilian adolescents in Nepal. Prediction modelling techniques were employed to predict individualized risk of depression at age 18 or older in the Nepali cohort using a penalized logistic regression model. Following a priori exclusions for prior depression and age, 55 child soldiers and 71 war-affected civilians were included in the final analysis. The model was well calibrated, had good overall performance, and achieved good discrimination between depressed and non-depressed individuals with an area under the curve (AUC) of 0.73 (bootstrap-corrected 95% confidence interval 0.62-0.83). The Brazilian model comprising seven matching sociodemographic predictors, was able to stratify individualized risk of depression in a Nepali adolescent cohort. Further testing of the model's performance in larger socio-culturally diverse samples in other geographical regions should be attempted to test the model's wider generalizability

    Using Grasses Morphogenetic Variables for Natural Grassland Grazing Management

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    In a perspective of ecologically sustainable agriculture, culturally accepted and economically feasible, natural pastures fits as one of the best options for Southern Brazil region. This study assessed the feasibility of rearing beef heifers from 12 to 18 months of age in natural pasture during its growing season (173 days). We evaluated two rest intervals in a natural pasture managed under rotational grazing. Intervals were defined based on the average thermal sum (degree-days) that fits to leaf expansion duration (average of two leaves) of native species of two grasses functional groups, according to Cruz et al. (2010). Only grasses were included in these groups considering their contribution above 65% of forage mass and also their ranking on two functional traits, specific leaf area and leaf dry matter content as reported by the above authors. One group was called resources’ capture functional group, favoring prostrate species with fast biomass accumulation (e.g. Axonopus affinis, Paspalum notatum) and the other resources’ conservation group, favoring tufted species efficient in conserving soil nutrients with higger standing biomass but lower accumulation rate (e.g. Aristida laevis, Saccharum angustifolium). The trial aims to incorporate a functional approach into management schedules for increasing grazing efficiency of natural grasslands production without losses in its biodiversity

    Environmental hazard assessment of a marine mine tailings deposit site and potential implications for deep-sea mining

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    Portmán Bay is a heavily contaminated area resulting from decades of metal mine tailings disposal, and is considered a suitable shallow-water analogue to investigate the potential ecotoxicological impact of deep-sea mining. Resuspension plumes were artificially created by removing the top layer of the mine tailings deposit by bottom trawling. Mussels were deployed at three sites: i) off the mine tailings deposit area; ii) on the mine tailings deposit beyond the influence from the resuspension plumes; iii) under the influence of the artificially generated resuspension plumes. Surface sediment samples were collected at the same sites for metal analysis and ecotoxicity assessment. Metal concentrations and a battery of biomarkers (oxidative stress, metal exposure, biotransformation and oxidative damage) were measured in different mussel tissues. The environmental hazard posed by the resuspension plumes was investigated by a quantitative weight of evidence (WOE) model that integrated all the data. The resuspension of sediments loaded with metal mine tails demonstrated that chemical contaminants were released by trawling subsequently inducing ecotoxicological impact in mussels' health. Considering as sediment quality guidelines (SQGs) those indicated in Spanish action level B for the disposal of dredged material at sea, the WOE model indicates that the hazard is slight off the mine tailings deposit, moderate on the mine tailings deposit without the influence from the resuspension plumes, and major under the influence of the resuspension plumes. Portmán Bay mine tailings deposit is a by-product of sulphide mining, and despite differences in environmental setting, it can reflect the potential ecotoxic effects to marine fauna from the impact of resuspension of plumes created by deep-sea mining of polymetallic sulphides. A similar approach as in this study could be applied in other areas affected by sediment resuspension and for testing future deep-sea mining sites in order to assess the associated environmental hazards.info:eu-repo/semantics/publishedVersio

    Age of Sexual Initiation, Psychiatric Symptoms, and Sexual Risk Behavior among Ecstasy and LSD Users in Porto Alegre, Brazil: A Preliminary Analysis

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    Ecstasy and LSD use is widespread in large Brazilian cities, but there is limited information on their use among young, middle-class, club goers in Brazil. We conducted standardized face-to-face interviews with 200 male and female ecstasy and/or LSD users, focusing on drug use and sexual history, current risk behaviors, and psychiatric symptomatology. Participants with early sexual debut (before 14) were more likely to report lifetime use of marijuana and powder and crack cocaine than those with later sexual initiation. Early sexual debut was associated with past year sexual risk behaviors, including having sex while high (Prevalence Ratio (PR)=1.3), having two or more sex partners (PR=1.3), as well as history of sexual abuse (PR=13.6). Depression and anxiety scores were similar by age of sexual initiation. The implications of these findings are discussed

    Interface Gráfica para o Robix

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    This work presents a graphical environment to simulate a robot arm linked, through an usb port, to a Robix robot arm controlled by an Arduino microcontroller, which is programmed to receive data from the graphical simulation program. The movements to be done by the Robix are programmed and verified by the operator. Then, this information is sent to the microcontroller, which drives the appropriate servomotors of the robot to perform the movements required in the simulation environment
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