2,000 research outputs found

    DC modulation noise in clustered particulate media

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    Mallinson’s theory of recording media noise is extended to ensembles where the particles have an easy axis distribution or are clustered. The effect of clusters is that there is a critical value of packing fraction at which noise in the demagnetised state switches to a minimum. Comparison is made with measurements of DC modulation noise in double layer MP tape

    Photo Acoustic Study Of Plants Exposed To Varying Light Intensity Growth Conditions: Spectral And Morphological Changes

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    In this paper we describe results of photo acoustic (PA) measurements carried out on various plants exposed to varying light intensity conditions. Depending on the species and light intensity conditions, the PA absorption spectra show differences in peaks associated with pigments and the cuticle. These differences are related to the spatial distribution of the pigments that differs from plant to plant. We have also performed systematic study of oxygen evolution at different wavelengths. The obtained oxygen spectra are equivalent to the action spectra usually acquired by determining the CO2 uptake and energy storage. The intensities of oxygen spectra exhibit differences depending on distinct morphology of plant. © EDP Sciences.125745748Marquezini, M.V., Cella, N., Mansanares, A.M., Vargas, H., Miranda, L.C.M., (1991) Meas. Sci. Technol., 2, p. 396Barja, P.R., Mansanares, A.M., (1998) Instrum. Sci. Technol., 26, p. 209Barja, P.R., Mansanares, A.M., Da Silva, E.C., Magalhães, A.C.N., Alves, P.L.C.A., (2001) Photosynthetica, 39, p. 489Salisbury, F.B., Ross, C.W., (1992) Plant Physiology, , Wadsworth Publishing Company, CaliforniaClark, J.B., Lister, G.R., (1975) Plant Physiol., 55, p. 401Carpentier, R., Larue, B., Leblanc, R.M., (1983) J. Physique Colloque C6, 44 (10 SUPL), pp. 355-360Veeranjaneyulu, K., Charland, M., Charlebois, D., Leblanc, R.M., (1991) Photosynth. Res., 30, p. 13

    Qualidade de carcaça de novilhos terminados com dietas contendo levedura, monensina e associação de ambos aditivos

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    To evaluate the effects of the supplementation of feed additives on carcass quality in beef cattle, 72 Nellore steers (339.5kg, 20-month old) were feedlot finished and fed for 91 days one of the following diets: 1) control with no additives; or added of 2) live yeast culture; 3) monensin; or 4) the association of both additives. After slaughter, renal, pelvic, and inguinal fat and hot carcass weights were recorded and carcass was split into muscle, bone, and trimmable fat. Carcass Longissimus muscle area and subcutaneous fat thickness at the 12th rib were measured and steaks of Longisimus muscle were taken to determine meat color, shear force, drip, and cooking losses. Yeast increased carcass dressing percentage but there were no effects on hot carcass weight, Longissimus area, subcutaneous fat thickness, percentage and weight of retail cut yield and trimmings. Feed additives had no effect on carcass pH, meat color, fat content, shear force, and drip losses. Supplementation of yeast, monensin or the association of both additives had no important effects on carcass traits and on meat quality of feedlot finished steers.Avaliaram-se os efeitos da suplementação de aditivos alimentares sobre a qualidade de carcaça em bovinos de corte. Usaram-se 72 novilhos Nelore com média de peso de 339,5kg e 20 meses de idade, terminados em confinamento e alimentados por 91 dias com uma das quatro dietas: 1) dieta controle sem aditivos, ou com a adição de 2) leveduras vivas, 3) monensina ou 4) associação entre ambos aditivos. Após o abate, os pesos da gordura renal, pélvica e inguinal e da carcaça foram medidos e a carcaça dividida em músculos, ossos e aparas. Foram mensurados a área de olho de lombo e a espessura de gordura subcutânea sobre o músculo Longissimus na região da 12ª costela e foram obtidos bifes para a determinação da cor, força de cisalhamento e perdas por cocção e cozimento da carne. A levedura aumentou o rendimento de carcaça, mas não houve efeito dos tratamentos sobre o peso de carcaça, porção comestível e aparas. Os aditivos não influenciaram o pH da carcaça, a cor, a gordura intramuscular, a força de cisalhamento e as perdas por exsudação da carne. A suplementação, com levedura e com monensina em associação ou separadamente, não teve efeito importante sobre a qualidade da carcaça em novilhos terminados em confinamento.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

    Characterization Of Human Skin Through Photoacoustic Spectroscopy

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    The photoacoustic technique is based on the absorption of modulated light by a sample and subsequent heat generation. This generates thermal waves that propagate in the surrounding media According to the Rosencwaig-Gersho Model, such waves produce the pressure oscillation detected as the photoacoustic signal. This technique allows the spectroscopic characterization of multilayer systems: as the thermal diffusion length varies with the modulation frequency of the absorbed light, the depth profile of a sample can be studied by the analysis of the photoacoustic signal at different modulation frequencies. In this work, photoacoustic spectroscopy was used to characterize different human skin samples. Measurements were performed at 70Hz and 17Hz, using a 1000W Xe arc lamp as the light source, for wavelengths between 240nm and 700nm. Skin samples were about 0,5cm diameter. It was possible to obtain the photoacoustic absorption spectra of the stratum corneum and of a deeper layer of epidermis; when the lower modulation frequency is utilized, photoacoustic spectroscopy characterizes the absorption of the whole epidermis, because in this case the thermal diffusion length is thicker than that of the stratum corneum. Photoacoustic spectroscopy was also employed to monitor the drying kinetics of the skin. This was done by analyzing the time evolution of the photoacoustic spectra of skin samples. Pre-treatment of the samples included different periods in a drying chamber. Measurements show that the photoacoustic spectra changes according to the humidity of the skin. Future work includes detailed monitoring of skin hydration.5325136142Morganti, P., Ruocco, E., Wolf, R., Ruocco, V., Percutaneous absorption and delivery systems (2001) Clinics in Dermatology, 19, pp. 489-501Junqueira, L.C., Carneiro, J., (1995) Histologia Básica, 8a Ed., pp. 301-303Bernengo, J.C., Gasquez, C., Falson-Rieg, F., Photoacoustics as a tool for cutaneous permeation studies (1998) High Temperatures-High Pressures, 30, pp. 619-624Gutiérrez-Juárez, G., Vargas-Luna, M., Córdova, T., Varela, J.B., Bernal-Alvarado, J.J., Sosa, M., In vivo measurement of the human skin absorption of toppically applied substances by photoacoustic technique (2002) Physiological Measurement, 23, pp. 1-12Puccetti, G., Lahjomri, F., Leblanc, R.M., Pulsed photoacoustic spectroscopy applied to the diffusion of sunscreen chromophores in human skin: The weakly absorbent regime (1997) Journal of Photochemistry and Photobiology B: Biology, 39, pp. 110-120Vinha, C.A., Haas, U., Qualitative and semiquantitative analysis of dried fruits and seasoning products of paprika using photoacoustic spectroscopy (1997) Journal of Agricultural and Food Chemistry, 45 (4), p. 127

    Multi-score Learning for Affect Recognition: the Case of Body Postures

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    An important challenge in building automatic affective state recognition systems is establishing the ground truth. When the groundtruth is not available, observers are often used to label training and testing sets. Unfortunately, inter-rater reliability between observers tends to vary from fair to moderate when dealing with naturalistic expressions. Nevertheless, the most common approach used is to label each expression with the most frequent label assigned by the observers to that expression. In this paper, we propose a general pattern recognition framework that takes into account the variability between observers for automatic affect recognition. This leads to what we term a multi-score learning problem in which a single expression is associated with multiple values representing the scores of each available emotion label. We also propose several performance measurements and pattern recognition methods for this framework, and report the experimental results obtained when testing and comparing these methods on two affective posture datasets

    Quinze anos de monitorização das comunidades biológicas do estuário do Tejo no âmbito da construção e funcionamento das ETARs do Portinho da Costa e da Mutela (Concelho de Almada): Experiência adquirida e ensinamentos para futuros casos semelhantes.

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    Desde 2001 que a Câmara Municipal de Almada tem vindo a promover, em colaboração com o MARE, a monitorização ambiental das regiões estuarinas sob influência das ETARs do Portinho da Costa e da Mutela, que vieram substituir efluentes não tratados emitidos sensivelmente nas mesmas regiões. O objetivo deste programa de monitorização consiste em avaliar as principais alterações ocorridas (na maioria dos casos positivas) nos ecossistemas estuarinos dos vários locais, após a entrada em funcionamento de ambas as infraestruturas. Estes 15 anos de estudos das comunidades bentónicas e de peixes locais têm permitido identificar variações nos padrões espácio-temporais destes compartimentos biológicos e identificar quais dessas evoluções podem ser presumivelmente relacionáveis com o funcionamento das infraestruturas e quais derivam provavelmente de flutuações naturais. Nesta comunicação são enunciados os pressupostos do estudo, descritos os delineamentos experimentais e metodologias de tratamento dos dados adotados, apresentados os principais resultados obtidos e discutidas as grandes dificuldades sentidas para cumprir os objetivos estabelecidos. Este conjunto de elementos será analisado numa perspetiva de como a experiência adquirida pode ser útil, no futuro, para casos semelhantes, sobretudo numa ótica da correta identificação dos verdadeiros efeitos infraestruturais e de despiste da influência de outros fatores concorrentes

    Frugivores At Higher Risk Of Extinction Are The Key Elements Of A Mutualistic Network

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    Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Most tree species rely on vertebrates for seed dispersal, and many vertebrates use fruits as food resources in tropical forests. Therefore, plant-frugivore interactions affect population dynamics and persistence in ecological communities. Plant-frugivore interactions often involve many species, forming networks of interacting plants and animals that play different roles in determining network organization. The network organization is the way interactions are structured in the community, which may have consequences for its ecological and evolutionary dynamics. Some species have greater influences on network organization and may be particularly important to species persistence. We identified the frugivores most important to the organization of networks of plants and frugivorous birds in three contiguous Atlantic forest sites in southeastern Brazil. We found that the species that contributed most to network organization were at higher risk of extinction. Among the main contributors to network organization were two cotingas and a toucan, large-bodied species that disperse seeds from many plants and are particularly vulnerable to habitat loss and hunting. As a consequence, ongoing extinctions may significantly affect the organization of plant-frugivore interactions in the studied system. We hypothesize that the crucial role of some threatened frugivores may occur in other seed dispersal systems in tropical communities, although the association between structural importance and degree of threat may be contingent on peculiarities of local communities and disturbances.951234403447CAPES; São Paulo Research Foundation; #2009/54422-8; FAPESP; São Paulo Research Foundation; #2010/11633-6; FAPESP; São Paulo Research FoundationFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Allesina, S., Tang, S., Stability criteria for complex ecosystems (2012) Nature, 483, pp. 205-208Almeida-Neto, M., Guimarães, P., Guimarães, P.R., Jr., Loyola, R.D., Ulrich, W., A consistent metric for nestedness analysis in ecological systems: Reconciling concept and measurement (2008) Oikos, 117, pp. 1227-1239Banks-Leite, C., Ewers, R.M., Metzger, J.P., Unraveling the drivers of community dissimilarity and species extinction in fragmented landscapes (2012) Ecology, 93, pp. 2560-2569Bascompte, J., Jordano, P., Plant-animal mutualistic networks: The architecture of biodiversity (2007) Annual Review of Ecology, Evolution, and Systematics, 38, pp. 567-593Bascompte, J., Jordano, P., Melián, C.J., Olesen, J.M., The nested assembly of plant-animal mutualistic networks (2003) Proceedings of the National Academy of Sciences USA, 100, pp. 9383-9387Carlo, T.A., Yang, S., Network models of frugivory and seed dispersal: Challenges and opportunities (2011) Acta Oecologica, 37, pp. 619-624Da Silva, J.M.C., Tabarelli, M., Tree species impoverishment and the future flora of the atlantic forest of Northeast Brazil (2000) Nature, 404, pp. 72-74(2008) Plano de Manejo Do Parque Estadual Intervales. 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