513 research outputs found

    Analysing Conjoint Analysis Data by a Random Coefficient Regression Model

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    2000 Mathematics Subject Classification: 62J12, 62K15, 91B42, 62H99.Since late 1960s conjoint analysis has been applied in estimating consumer preferences in marketing research. This article discusses how to model the data coming from a full or a fractional factorial design within a unique regression model, as an alternative to the estimation done by n independent multiple linear regression models, one for each subject. The advantage of the method presented here resides in the possibility of computing correct standard errors for the conjoint analysis utility values based on a particular group of subjects. The model assumes that the utility values within subjects could be correlated

    Curvas de salários dinâmicas: um estudo dos determinantes da histerese do desemprego no Brasil

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    This work estimates elasticity wage/long-term unemployment and checking which individuals groups are more affected by unemployment hysteresis phenomenon, using Household Sample National Survey (PNAD) published by the Brazilian Bureau of Geography and Statistics (IBGE) of six metropolitan regions - São Paulo, Rio de Janeiro, Recife, Salvador, Belo Horizonte e Porto Alegre – between 1997 and 2005. Behind of model of Dynamic Wage Curve, the results show strong wage flexibility in labor market. However, analyzing only formal workers, this result show that hysteresis originates of wage rigidity. In addition, it was observed that men, whites and individuals with higher education levels are less affected by long-term unemployment caused of wage flexibility these groups, among other reasons.Labor Market, Dynamic Wage Curve, Unemployment, Hysteresis

    Microvesicles: Novel Biomarkers for Neurological Disorders

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    Microvesicles (MVs) are released by most cell types in physiological conditions, but their number is often increased upon cellular activation or neoplastic transformation. This suggests that their detection may be helpful in pathological conditions to have information on activated cell types and, possibly, on the nature of the activation. This could be of paramount importance in districts and tissues that are not accessible to direct examination, such as the central nervous system. Increased release of MVs has been described to be associated to the acute or active phase of several neurological disorders. While the subcellular origin of MVs (exosome or ectosomes) is basically never addressed in these studies because of technical limitations, the cell of origin is always identified. Endothelium- or platelet-derived MVs, detected in plasma or serum, are linked to neurological pathologies with a vascular or ischemic pathogenic component, and may represent a very useful marker to support therapeutic choices in stroke. In neuroinflammatory disorders, such as multiple sclerosis, MVs of oligodendroglial, or microglial origin have been described in the cerebrospinal fluid and may carry, in perspective, additional information on the biological alterations in their cell of origin. Little specific evidence is available in neurodegenerative disorders and, specifically, MVs of neural origin have never been investigated in these pathologies. Few data have been reported for neuroinfection and brain trauma. In brain tumors, despite the limited number of studies performed, results are very promising and potentially close to clinical translation. We here review all currently available data on the detection of MVs in neurological diseases, limiting our search to exclusively human studies. Current literature and our own data indicate that MVs detection may represent a very promising strategy to gain pathogenic information, identify therapeutic targets, and select specific biomarkers for neurological disorders

    Variation in the amounts of volatile constituents of Cymbopogon citratus (DC) Staf, Poaceae, collected in different regions of São Paulo State

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    The essential oil extracted from Cymbopogon citratus (DC) Staf, Poaceae, is rich in citral and has many applications in chemical and pharmaceutical industry. The aims of this study were evaluate the amount of citral in populations of C. citratus collected in two different regions (Ibiúna and Pindamonhangaba, São Paulo State). The essential oil extracted of a cultivated population in Pidamonhangaba-SP, showed a high content of citral (approximately 96.0%), while the essential oil from Ibiuna-SP, showed citral and high amounts of another monoterpene, geraniol. Additionally, the essential oils from this population of C. citratus were extracted and analyzed during 24 h (each 3 h), being the major concentration of citral in the night period, indicating that studies which evaluated the chemical differences associated to circadian changes. The components of essential oils were identified through 13C NMR, GC/MS, GC and Kovat's index.O óleo essencial extraído de Cymbopogon citratus (DC) Staf, Poaceae, é rico em citral sendo amplamente empregado na indústria química e farmacêutica. Os objetivos desse estudo foram avaliar o conteúdo de citral entre populações de C. citratus coletados em duas regiões diferentes (Ibiúna e Pindamonhangaba, Estado de São Paulo). O óleo essencial extraído de uma população cultivada em Pindamonhangaba-SP apresentou uma concentração alta de citral (aproximadamente 96,0%), enquanto que o óleo extraído da população de Ibiúna-SP apresentou, além de citral, proporções elevadas de outro monoterpeno, o geraniol. Adicionalmente, os óleos essenciais obtidos desta população de C. citratus foram extraídos e analisados ao longo de 24 h (a cada 3 h), sendo que o teor de citral foi maior no período da noite, o que mostra a importância de estudos que avaliam as diferenças químicas associadas às mudanças circadianas. Os componentes dos óleos essenciais foram identificados por RMN de 13C, CG/EM e CG através do índice de Kovats.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade de Taubaté Departamento de AgronomiaCentro Universitário Fundação Instituto Educacional de OsascoUniversidade Federal de São Paulo (UNIFESP) Departamento de PsicobiologiaUniversidade Federal de São Paulo (UNIFESP) Departamento de Ciências Exatas e da TerraUNIFESP, Depto. de PsicobiologiaUNIFESP, Depto. de Ciências Exatas e da TerraSciEL

    Effect of age and strain on haematological and gasometric parameters in selected and non-selected broiler chickens

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    This investigation was undertaken to evaluate the effect of age and strain on haematological and gasometric parameters in selected and non-selected broiler chickens. Forty selected and 10 nonselected male broiler chickens were used. Blood samples were withdrawn at 21 and 42 days of age, and haematological parameters were determined including (red blood cell (RBC), white blood cell (WBC), hemoglobin (Hb), hematocrit (Ht), mean cell volume (MCV), mean cell hemoglobin (MCH) and mean cell hemoglobin concentration (MCHC)) and gasometric pH, partial pressure of oxgen (p 0 2) and partial pressure of carbon dioxide (pC02) were determined. The results showed that almost all studied parameters are affected by broiler strain and age. Selected broiler shown lower red blood cell (RBC) count and higher mean cell volume (MCV) at 21 days of age, when compared to that of 42 day old animals, and an inverse relation was verified by non-selected broiler. These data suggest that selected broiler chickens could have higher sensitivity to alterations in pulmonary rheological parameters at early age, and triggering the ascite’s syndrome.Objetivou-se investigar o efeito de idade e linhagem sobreparâmetros hematológicos e gasométricos de frangos selecionados e não selecionados. Foram utilizados somente frangos machos, sendo 40 selecionados e 10 não-selecionados. Amostras de sangue foram colhidas aos 21 e 42 dias de idade e determinados os parâmetros hematológicos (eritrócito, leucócito, hemoglobina, hematócrito, volume globular médio, hemoglobina globular média e concentração de hemoglobina no eritrócito), e os parâmetros gasométricos (pH, pressão parcial de oxigênio e pressão parcial de dióxido de carbono). Os resultados mostraram que os parâmetros hematológicos e gasométricos são afetados pela idade e linhagem do frango. As aves selecionadas apresentaram um número de eritrócito menor e um volume globular médio maior aos 21 dias de idade quando comparados aos animais de 42 dias de idade, e uma relação inversa foi verificada nos frangos não selecionados. Estes dados sugerem que quando jovens os frangos selecionados podem ser mais sensíveis às alterações nos parâmetros pulmonares e desenvolver a síndrome da Ascite

    Multiplexing of encrypted data using fractal masks

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    This paper was published in OPTICS LETTERS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OL.37.002895. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under lawIn this Letter, we present to the best of our knowledge a new all-optical technique for multiple-image encryption and multiplexing, based on fractal encrypting masks. The optical architecture is a joint transform correlator. The multiplexed encrypted data are stored in a photorefractive crystal. The fractal parameters of the key can be easily tuned to lead to a multiplexing operation without cross talk effects. Experimental results that support the potential of the method are presented.This research was performed under grants TWAS-UNESCO Associateship Scheme at Centres of Excellence in the South, CONICET No. 0863 (Argentina), ANCYT PICT 1167 (Argentina), and Facultad de Ingenieria, Universidad Nacional de La Plata No. 11/I125 (Argentina), Sostenibilidad 2011-2012, and CODI (Universidad de Antioquia-Colombia). W. D. Furlan and J. A. Monsoriua acknowledge financial support from Ministerio de Economia y Competitividad (grant FIS2011-23175), Generalitat Valenciana (grant PROMETEO2009-077), and Universitat Politecnica de Valencia (grants PAID-05-11 and PAID-02-11), Spain.Barrera, J.; Tebaldi, M.; Amaya, D.; Furlan, W.; Monsoriu Serra, JA.; Bolognini, NA.; Torroba, RD.... (2012). Multiplexing of encrypted data using fractal masks. Optics Letters. 37(14):2895-2897. doi:10.1364/OL.37.002895S289528973714Refregier, P., & Javidi, B. (1995). Optical image encryption based on input plane and Fourier plane random encoding. Optics Letters, 20(7), 767. doi:10.1364/ol.20.000767Matoba, O., & Javidi, B. (1999). Encrypted optical memory system using three-dimensional keys in the Fresnel domain. Optics Letters, 24(11), 762. doi:10.1364/ol.24.000762Unnikrishnan, G., Joseph, J., & Singh, K. (2000). Optical encryption by double-random phase encoding in the fractional Fourier domain. Optics Letters, 25(12), 887. doi:10.1364/ol.25.000887Nomura, T. (2000). Polarization encoding for optical security systems. Optical Engineering, 39(9), 2439. doi:10.1117/1.1288369Tebaldi, M., Furlan, W. D., Torroba, R., & Bolognini, N. (2009). Optical-data storage-readout technique based on fractal encrypting masks. Optics Letters, 34(3), 316. doi:10.1364/ol.34.000316Situ, G., & Zhang, J. (2005). Multiple-image encryption by wavelength multiplexing. Optics Letters, 30(11), 1306. doi:10.1364/ol.30.001306Liu, Z., & Liu, S. (2007). Double image encryption based on iterative fractional Fourier transform. Optics Communications, 275(2), 324-329. doi:10.1016/j.optcom.2007.03.039Hwang, H.-E., Chang, H. T., & Lie, W.-N. (2009). Multiple-image encryption and multiplexing using a modified Gerchberg-Saxton algorithm and phase modulation in Fresnel-transform domain. Optics Letters, 34(24), 3917. doi:10.1364/ol.34.003917Matoba, O., & Javidi, B. (1999). Encrypted optical storage with angular multiplexing. Applied Optics, 38(35), 7288. doi:10.1364/ao.38.007288Fredy Barrera, J., Henao, R., Tebaldi, M., Torroba, R., & Bolognini, N. (2006). Multiplexing encryption–decryption via lateral shifting of a random phase mask. Optics Communications, 259(2), 532-536. doi:10.1016/j.optcom.2005.09.027Henao, R., Rueda, E., Barrera, J. F., & Torroba, R. (2010). Noise-free recovery of optodigital encrypted and multiplexed images. Optics Letters, 35(3), 333. doi:10.1364/ol.35.000333Barrera, J. F., Henao, R., Tebaldi, M., Torroba, R., & Bolognini, N. (2006). Multiple image encryption using an aperture-modulated optical system. Optics Communications, 261(1), 29-33. doi:10.1016/j.optcom.2005.11.055Mosso, F., Barrera, J. F., Tebaldi, M., Bolognini, N., & Torroba, R. (2011). All-optical encrypted movie. Optics Express, 19(6), 5706. doi:10.1364/oe.19.005706Monsoriu, J. A., Saavedra, G., & Furlan, W. D. (2004). Fractal zone plates with variable lacunarity. Optics Express, 12(18), 4227. doi:10.1364/opex.12.00422

    The therapeutic effect of mesenchymal stem cell transplantation in experimental autoimmune encephalomyelitis is mediated by peripheral and central mechanisms

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    Stem cells are currently seen as a treatment for tissue regeneration in neurological diseases such as multiple sclerosis, anticipating that they integrate and differentiate into neural cells. Mesenchymal stem cells (MSCs), a subset of adult progenitor cells, differentiate into cells of the mesodermal lineage but also, under certain experimental circumstances, into cells of the neuronal and glial lineage. Their clinical development, however, has been significantly boosted by the demonstration that MSCs display significant therapeutic plasticity mainly occurring through bystander mechanisms. These features have been exploited in the effective treatment of experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis where the inhibition of the autoimmune response resulted in a significant amelioration of disease and decrease of demyelination, immune infiltrates and axonal loss. Surprisingly, these effects do not require MSCs to engraft in the central nervous system but depend on the cells' ability to inhibit pathogenic immune responses both in the periphery and inside the central nervous system and to release neuroprotective and pro-oligodendrogenic molecules favoring tissue repair. These results paved the road for the utilization of MSCs for the treatment of multiple sclerosis
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