1,283 research outputs found

    Advanced solutions for quality-oriented multimedia broadcasting

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    Multimedia content is increasingly being delivered via different types of networks to viewers in a variety of locations and contexts using a variety of devices. The ubiquitous nature of multimedia services comes at a cost, however. The successful delivery of multimedia services will require overcoming numerous technological challenges many of which have a direct effect on the quality of the multimedia experience. For example, due to dynamically changing requirements and networking conditions, the delivery of multimedia content has traditionally adopted a best effort approach. However, this approach has often led to the end-user perceived quality of multimedia-based services being negatively affected. Yet the quality of multimedia content is a vital issue for the continued acceptance and proliferation of these services. Indeed, end-users are becoming increasingly quality-aware in their expectations of multimedia experience and demand an ever-widening spectrum of rich multimedia-based services. As a consequence, there is a continuous and extensive research effort, by both industry and academia, to find solutions for improving the quality of multimedia content delivered to the users; as well, international standards bodies, such as the International Telecommunication Union (ITU), are renewing their effort on the standardization of multimedia technologies. There are very different directions in which research has attempted to find solutions in order to improve the quality of the rich media content delivered over various network types. It is in this context that this special issue on broadcast multimedia quality of the IEEE Transactions on Broadcasting illustrates some of these avenues and presents some of the most significant research results obtained by various teams of researchers from many countries. This special issue provides an example, albeit inevitably limited, of the richness and breath of the current research on multimedia broadcasting services. The research i- - ssues addressed in this special issue include, among others, factors that influence user perceived quality, encoding-related quality assessment and control, transmission and coverage-based solutions and objective quality measurements

    Enzymatic synthesis of γ-glutamyl derivatives catalyzed by a new mutant γ-glutamyltransferase with improved transpeptidase activity

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    Despite their potential applicative interest as biologically active compounds and as flavor enhancers, \u3b3-glutamyl derivatives are commercially underexploited compounds. This is mainly due to the difficulties connected with their supply at a reasonable cost. As a consequence, enzymatic approaches to their preparation, based on the use of \u3b3-glutamyltransferases (GGTs), have been proposed1 to circumvent both the low-yielding extractive procedures from natural sources and the troublesome chemical synthesis, rendered uneconomical by the need of protection and deprotection steps. GGTs catalyze the transfer of a \u3b3-glutamyl moiety from a donor substrate (e.g. glutathione) to the primary amino group of an acceptor compound in a so-called transpeptidation reaction, through the formation of a \u3b3-glutamyl-enzyme intermediate. However, also the use of GGTs as biocatalysts is not free from drawbacks. In addition to the transpeptidase activity, GGTs show a non-negligible hydrolase activity towards both the donor substrate and the newly formed transpeptidation product, affording irreversibly glutamic acid.2 In our ongoing studies on bacterial GGTs, we found that the presence of the lid loop \u2013 a short amino acids sequence covering the active site in most of the known GGTs \u2013 not only affects substrate selection, but also modulates hydrolase/transpeptidase activities.3 Within the TailGluTran Project,4 aimed at the development of mutant GGTs with improved transpeptidase activity, is currently under investigation a mutant enzyme obtained by inserting the sequence of the lid loop on the structure of a GGT naturally lacking it. The mutant enzyme shows promising high transpeptidase activity with respect to wild type counterparts and represents a starting point for further modifications in the search of a suitable biocatalyst intended for preparative purposes

    Synthesis of γ-glutamyl derivatives of sulfur-containing amino acids in a multigram scale via a two-step, one-pot procedure

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    \u3b3-Glutamyl derivatives of sulfur amino acids have been prepared in multigram scale starting from readily available starting materials. The synthesis comprises two one-pot operations, both consisting of two reactions. In the first operation, N-phtaloyl-l-glutamic acid anhydride is obtained from l-glutamic acid and phtalic anhydride. In the second one, N-phtaloyl-l-glutamic acid anhydride is used to acylate amino acids and the N-phtaloyl protecting group is removed. The described approach offers a viable entry to \u3b3-glutamyl derivatives of sulfur-containing amino acids with flavor-enhancer and nutraceutical properties

    Sistema de informação para o agronegócio da cana-de-açúcar.

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    RESUMO: Este trabalho apresenta esforços de organização de informações e de melhoria de ferramentas de difusão pela Embrapa Informática Agropecuária, com foco no sistema agroindustrial da cana-de-açúcar. Apresenta-se a implementação de uma ferramenta WebGIS e os resultados de espacialização e organização das informações sobre empreendimentos do agronegócio. A iniciativa mostra-se promissora para adoção pela Embrapa como referência para análise do agronegócio e difusão de informações.SBIAgro 2011

    Assessment of water quality and soil salinity in the agricultural coastal plain (Ravenna, North Italy)

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    To improve knowledge on salt leaching suitability on different soils, in Arenosols and Cambisols croplands in the coastal area of Ravenna (Italy), soil samples were collected in the non-irrigation winter period and irrigation summer period. Concurrently, waters of the canal network were also investigated. Soil samples were analyzed for pH, carbonate, total organic carbon (TOC), particle size distribution, electrical conductivity (EC), bulk density (BD) and water content at field capacity (FC). Water samples were investigated for pH, EC, biological and chemical oxygen demand, sodium adsorption ratio, phosphorus, nitrogen, sulfates and chlorides. All soils had low TOC concentrations and Arenosols showed the lowest clay content, BD and FC. Soils had similar EC values in winter, but in summer the lowest ones were observed in Arenosols, suggesting that irrigation mitigated salinization in Arenosols, while the high clay content, BD and FC prevented or limited the salt leaching in Cambisols. In summer, the increase of total nitrogen and biological oxygen demand, especially in drainage channels, might suggest the leaching of soluble nutrients and organic matter from soils due to the high irrigation water volumes. Finally, our findings stress the need to consider soil type and properties to contrast soil salinization without negative effects on soil C leaching caused by salt leaching practice

    The body I live in. Perceptions and meanings of body dissatisfaction in young transgender adults: a qualitative study

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    Body dissatisfaction in individuals with Gender Incongruence (GI) represents a primary source of su↵ering. Several studies have highlighted how this su↵ering has psychological, physical, and biological implications. This work aims to explore experiences related to body dissatisfaction and investigate the issues associated with living in a body perceived as incongruent for individuals with GI. Thirty-six individuals, aged between 18 and 30 years old and at stage T0 of hormone treatment, participated in the study. Body dissatisfaction and experiences related to it were investigated using the Clinical Diagnostic Interview. The Consensual Qualitative Research methodology was applied to the transcripts of the interviews. Several themes emerged: experiences with GI development, experiences with puberty and bodily changes, perception of one’s body, psychological problems and complex behavioral patterns related to body dissatisfaction. Results pointed out the complexity implied in the relationship with one’s body for individuals with GI, highlighting specific aspects of body dissatisfaction among these individuals (e.g., eating disorders, sexual diculties, social withdrawal). This study underlines the need for a deeper understanding of some aspects of GI to better define guidelines for a correct assessment of it. In this way it will be easier to avoid negative outcomes for the psychological and general health of transgender people

    Regional climate models' performance in representing precipitation and temperature over selected Mediterranean areas

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    This paper discusses the relative performance of several climate models in providing reliable forcing for hydrological modeling in six representative catchments in the Mediterranean region. We consider 14 Regional Climate Models (RCMs), from the EU-FP6 ENSEMBLES project, run for the A1B emission scenario on a common 0.22° (about 24 km) rotated grid over Europe and the Mediterranean region. In the validation period (1951 to 2010) we consider daily precipitation and surface temperatures from the observed data fields (E-OBS) data set, available from the ENSEMBLES project and the data providers in the ECA&D project. Our primary objective is to rank the 14 RCMs for each catchment and select the four best-performing ones to use as common forcing for hydrological models in the six Mediterranean basins considered in the EU-FP7 CLIMB project. Using a common suite of four RCMs for all studied catchments reduces the (epistemic) uncertainty when evaluating trends and climate change impacts in the 21st century. We present and discuss the validation setting, as well as the obtained results and, in some detail, the difficulties we experienced when processing the data. In doing so we also provide useful information and advice for researchers not directly involved in climate modeling, but interested in the use of climate model outputs for hydrological modeling and, more generally, climate change impact studies in the Mediterranean region

    Amazonian Buriti Oil: Chemical Characterization And Antioxidant Potential

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    Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Buriti oil is an example of an Amazonian palm oil of economic importance. The local population uses this oil for the prevention and treatment of different diseases; however, there are few studies in the literature that evaluate its properties. In this study, detailed chemical and antioxidant properties of Buriti oil were determined. The predominant fatty acid was oleic acid (65.6%) and the main triacylglycerol classes were tri-unsaturated (50.0%) and di-unsaturated-mono-saturated (39.3%) triacylglycerols. The positional distribution of the classes of fatty acids on the triacylglycerol backbone indicated a saturated and unsaturated fatty acid relationship similar in the three-triacylglycerol positions. All tocopherol isomers were present, with a total content of 2364.1 mg.kg(-1). alpha-tocopherol constitutes 48% of the total tocopherol content, followed by gamma-tocopherol (45%). Total phenolic (107.0 mg gallic acid equivalent.g(-1) oil) and beta-carotene (781.6 mg.kg(-1)) were particularly high in this oil. The highest antioxidant activity against the free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) was obtained at an oil concentration of 50 mg.mL(-1) (73.15%). The antioxidant activity evaluated by the Oxygen Radical Absorbance Capacity (ORAC) was 95.3 mu mol Trolox equivalent.g(-1) oil. These results serve to present Buriti oil as an Amazonian resource for cosmetic, food and pharmaceuticals purposes.672National Council for the Improvement of Higher Education (Capes)Sao Paulo Research Foundation (Fapesp) [2012-22774-5, 2012-22829-4]Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

    Earthquakes in a fault system embedded in an elastic body subject to increasing shear stress

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    We consider the faults of an elastic body subject to an increasing stress and the stress field generated by slip on a fault. The slip along the fault releases the stress component parallel to the slip, but the component normal to the fault is not released and increases in time at the same rate as the shear affecting the body. The effect is an increase of the value of the force necessary to cause the subsequent slip; and, if the shear increases linearly, it causes an increase of the time intervals between the earthquakes on the fault, that is between the stress drop p and the slip s. The density distribution of p in a given time interval is computed; it is found that rigorously it is not a power law although it is a decreasing function of p. It is also seen that, as in the cases in which it was assumed that the component of the stress field locking the fault, after each earthquake, in the time interval to the next earthquake, would be anelastically released, the logarithm of the density distribution of the moments of the earthquakes is a linear function of log (M0 ) and a linear function of M in any time interval; M0 and M being the scalar seismic moment and the magnitude, respectively. Conditions for the existence of these linear relationships are discussed finding that a sufficient condition, when the range of p is not exceptionally large, is that the density distribution of p be of the type log (p), which includes the case when it is independent of the fault linear size l. The Gutenberg-Richter frequency-magnitude relationship and the conditions to obtain aftershocks and seismic swarms generated by this model are presented and discussed. In order to obtain the observed density distribution of earthquakes one or several hypotheses can be done: 1) the stress locking the faults, between successive earthquakes of the same fault, is released anelastically; 2) the density distribution of the sizes of the faults is such as to cause the logarithm of the density distribution of log (M0) and of M to be linear; 3) the density distribution of log M0 (M) is linear and the linearity factor is related to the density distribution of the stress drop and not to that of the linear dimensions of the faults
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