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The present work reports the use of anthocyanins extracted from mulberry (Morus Alba L.), raspberry (Rubus Idaeus L.) and blueberry (Vaccinium myrtillus L.) as sensitizers in dye-sensitized solar cells. The conversion efficiency of these devices is dependent on the extracts employed and can be rationalized in terms of their composition and spectral properties. Solar cells sensitized by the mulberry extract showed the highest efficiency among the fruits investigated. Moreover, a 16 cm2 active area solar cell with the mulberry extract has presented fair good efficiency of conversion for natural dye-based solar cells, besides stability over twenty weeks, showing perspectives for developing these low cost devices with a commercial viability.

Despite the notable progress in physically-based rendering, there is still a long way to go before one can automatically generate predictable images of organic materials such as human skin. In this tutorial, the main physical and biological aspects involved in the processes of propagation and absorption of light by skin tissues are examined. These processes affect not only skin appearance, but also its health. For this reason, they have also been the object of study in biomedical research. The models of light interaction with human skin developed by the biomedical community are mainly aimed at the simulation of skin spectral properties which are used to determine the concentration and distribution of various substances. In computer graphics, the focus has been on the simulation of light scattering properties that affect skin appearance. Computer models used to simulate these spectral and scattering properties are described in this tutorial, and their strengths and limitations discussed. Keywords: natural phenomena, biologically and physically-based rendering.

(3) Resumo†n†As propriedades espectrais da vegetaAao podem ser utilizadas para o monitoramento das condiAies de crescimento da vegetaAao ao longo do ano, assim como a estimativa da produtividade das espOcies, por meio de tOcnicas de sensoriamento remoto. Para tanto, O necessAErio, primeiramente, caracterizar espectralmente as espOcies que compiem a vegetaAao de um ecossistema. O†objetivo deste trabalho foi caracterizar a reflect‚ncia do Paspalum notatum Flgge var. notatum crescendo em diferentes nIveis de adubaAao nitrogenada. Foi realizado um experimento de campo na EstaAao Experimental AgronUmica da Universidade Federal do Rio Grande do Sul (30 o 5'22'' S e 51 o 39'8'' W), utilizando-se um espectrorradiUmetro portAEtil, em parcelas de P.†notatum adubadas com 0, 200 e 400†kg ha -1 de N. A resposta espectral do P.†notatum foi alterada pelas variaAies na quantidade de biomassa do dossel, provocadas por diferenAas nos nIveis de adubaAao nitrogenada. Os†aumentos na quantidade de biomassa provocaram diminuiAao da reflect‚ncia na porAao visIvel do espectro e aumento na porAao infravermelho, o que mostra que a anAElise da reflect‚ncia O um bom indicador das mudanAas que ocorrem em um dossel. Termos para indexaAao: biomassa, cobertura vegetal, reflect‚ncia, espectrometria. Spectral characterization of Paspalum notatum under different nitrogen fertilization Abstract†n†Remote sensing techniques using spectral properties of canopies may be used to monitor vegetation growth conditions throughout the year, as well as to estimate the yield of different species. However, before these techniques can be used, it†is necessary to establish the spectral properties of each of the different species which make up the landscape. The objective of this study was to characterize the spectral reflectance of Paspalum notatum Flgge var.†notatum, growing on different levels of nitrogen fertilization. A†field experiment was carried out at the Agronomic Experimental Station of Universidade Federal do Rio Grande do Sul, Brazil (30"5'22'' S, 51"39''8'' W), using a portable spectroradiometer, on plots with P. †notatum fertilized with 0, 200 and 400†kg†ha -1 of nitrogen. The spectral response of P.†notatum changed in response to increases in biomass caused by the different levels of nitrogen fertilization used. Increases in biomass resulted in a reduction in reflectance on the visible portion of the spectrum and an increase on the infrared portion, indicating, therefore, that the reflectance analysis is a good indicator of plant canopy status.