6 research outputs found

    Artificial limb representation in amputees

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    The human brain contains multiple hand-selective areas, in both the sensorimotor and visual systems. Could our brain repurpose neural resources, originally developed for supporting hand function, to represent and control artificial limbs? We studied individuals with congenital or acquired hand-loss (hereafter one-handers) using functional MRI. We show that the more one-handers use an artificial limb (prosthesis) in their everyday life, the stronger visual hand-selective areas in the lateral occipitotemporal cortex respond to prosthesis images. This was found even when one-handers were presented with images of active prostheses that share the functionality of the hand but not necessarily its visual features (e.g. a \u27hook\u27 prosthesis). Further, we show that daily prosthesis usage determines large-scale inter-network communication across hand-selective areas. This was demonstrated by increased resting state functional connectivity between visual and sensorimotor hand-selective areas, proportional to the intensiveness of everyday prosthesis usage. Further analysis revealed a 3-fold coupling between prosthesis activity, visuomotor connectivity and usage, suggesting a possible role for the motor system in shaping use-dependent representation in visual hand-selective areas, and/or vice versa. Moreover, able-bodied control participants who routinely observe prosthesis usage (albeit less intensively than the prosthesis users) showed significantly weaker associations between degree of prosthesis observation and visual cortex activity or connectivity. Together, our findings suggest that altered daily motor behaviour facilitates prosthesis-related visual processing and shapes communication across hand-selective areas. This neurophysiological substrate for prosthesis embodiment may inspire rehabilitation approaches to improve usage of existing substitutionary devices and aid implementation of future assistive and augmentative technologies

    Climate variations in greenhouse cultivated with gerbera and relationship with external conditions Variações meteorológicas em ambiente protegido cultivado com gérberas e suas relações com as condições externas

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    Black meshes used in greenhouses provide shade to plants, affecting photosynthesis and presenting certain properties that change the microclimatic conditions in these environments. The objective of this study was to evaluate the variation in climate elements in greenhouse cultivated with gerbera (Gerbera jamesonii, Vr. Rambo) in relation to external conditions and the reference evapotranspiration (ETo) at Teresina, State of Piauí, Brazil. The measurements were obtained from July to October 2007 by an automatic data acquisition system installed inside and outside the greenhouse. The global solar radiation, evapotranspiration, precipitation, temperature, relative humidity, and wind speed were estimated. The results showed that major effect of the shading occurred on the mean air temperature during the 120 days, making it higher than the external environment. Inside the greenhouse, mean values of relative air humidity, reference evapotranspiração, global solar radiation and wind speed were lower compared to those outside the greenhouse.<br>Os ambientes protegidos cobertos com malha negra fornecem sombreamento às plantas, têm forte influência no processo da fotossíntese e possuem propriedades particulares que interferem nas condições micrometeorológicas desses ambientes. Objetivou-se, neste trabalho, avaliar os elementos meteorológicos no interior do ambiente protegido cultivado com gérbera (Gerbera jamesonii, Vr. Rambo) em relação ao ambiente externo e na evapotranspiração de referência (ETo), a qual foi correlacionada às variáveis ambientais em Teresina-PI. No período de julho a outubro de 2007, os elementos meteorológicos foram obtidos por um sistema de aquisição de dados automático instalado no interior do ambiente protegido e externamente. Estimaram-se a radiação solar global, temperatura, umidade relativa do ar, evapotranspiração de referência, precipitação e velocidade do ar. Os resultados mostraram que o maior efeito da cobertura ocorreu sobre a temperatura média do ar durante os 120 dias, tornando-as acima das verificadas no ambiente exterior. Foram observados no ambiente protegido, valores médios de umidade relativa do ar, evapotranspiração de referência, radiação solar global e velocidade do vento, inferiores aos obtidos em condição de campo

    Alterações micrometeorológicas em vinhedos pelo uso de coberturas de plástico Micrometeorological alterations in vineyards by using plastic covering

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    O objetivo deste trabalho foi avaliar os efeitos da cobertura de plástico sobre alguns elementos meteorológicos que formam o microclima de vinhedos de Vitis vinifera L., cultivar Moscato Giallo, em Flores da Cunha, na Serra Gaúcha. O experimento foi conduzido na safra 2005/2006, com os tratamentos: fileiras de plantas descobertas; e fileiras de plantas cobertas com plástico transparente tipo ráfia, com 160 µm de espessura. Medições contínuas de radiação fotossinteticamente ativa, temperatura e umidade do ar, e velocidade do vento foram realizadas: acima da cobertura; entre a cobertura e o dossel; sobre o dossel descoberto; e junto aos cachos de ambos tratamentos. Estimou-se a evapotranspiração de referência nos dois tratamentos. Da radiação fotossinteticamente ativa incidente, 67,5% chegou ao dossel coberto, 16% atingiu os cachos cobertos e 36% chegou aos cachos descobertos. A cobertura aumentou em 3,4ºC as temperaturas máximas do ar junto às plantas. A umidade relativa do ar diurna foi menor, enquanto a pressão de vapor e o deficit de saturação foram superiores debaixo da cobertura. A velocidade do vento foi reduzida pela cobertura em 88%. No ambiente coberto, a evapotranspiração de referência foi 65% daquela do ambiente externo. Embora aumente as temperaturas diurnas, a cobertura de plástico promoveu redução na demanda evaporativa do vinhedo.<br>The objective of this work was to evaluate the effects of plastic covering on the microclimate of vineyards (Vitis vinifera L., cultivar Moscato Giallo), in Serra Gaúcha region in Rio Grande do Sul State, Brazil. The experiment was performed in Flores da Cunha, RS, during the 2005/2006 growing season. It comprised uncovered and covered rows of vines, using a 160 µm thick plastic film. Photossinthetically active radiation (PAR), air temperature and humidity, and wind velocity were monitored: over the plastic covering; between the film and the canopy; over the uncovered canopy; and close to grapes of both treatments. Reference evapotranspiration was estimated for both treatments. From the incoming PAR, 67.5% reached the covered canopy, 16% reached the covered grapes, and 36% reached the uncovered grapes. The plastic covering increased by 3.4ºC the maximum air temperatures close to plants. Diurnal air relative humidity was reduced, while water vapor pressure and vapor pressure deficit were increased because of the plastic covering, which also reduced in 88% the wind velocity in comparison to open air. The reference evapotranspiration on the covered canopy was 35% lower than in open air. Although increasing diurnal air temperatures, the plastic covering may reduce the evaporative demand on vineyards, by reducing the incoming solar radiation and the wind velocity

    sPlot - A new tool for global vegetation analyses

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    Aims: Vegetation-plot records provide information on the presence and cover or abundance of plants co-occurring in the same community. Vegetation-plot data are spread across research groups, environmental agencies and biodiversity research centers and, thus, are rarely accessible at continental or global scales. Here we present the sPlot database, which collates vegetation plots worldwide to allow for the exploration of global patterns in taxonomic, functional and phylogenetic diversity at the plant community level. Results: sPlot version 2.1 contains records from 1,121,244 vegetation plots, which comprise 23,586,216 records of plant species and their relative cover or abundance in plots collected worldwide between 1885 and 2015. We complemented the information for each plot by retrieving climate and soil conditions and the biogeographic context (e.g., biomes) from external sources, and by calculating community-weighted means and variances of traits using gap-filled data from the global plant trait database TRY. Moreover, we created a phylogenetic tree for 50,167 out of the 54,519 species identified in the plots. We present the first maps of global patterns of community richness and community-weighted means of key traits. Conclusions: The availability of vegetation plot data in sPlot offers new avenues for vegetation analysis at the global scale
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