Creando valor a través de las TIC: nuevos intermediarios

Este trabajo analiza cómo se puede crear valor a través del uso de las TIC. Para ello se utiliza el Modelo de creación de valor en e-business desarrollado por Amit y Zott (2001) y se aplica a una tipología de nuevos intermediarios que opera en el sector de los contenidos digitales: gregadores de noticias. Para lograr este objetivo, se ha realizado un estudio exploratorio y un estudio de casos a través de entrevistas personales con informadores estratégicos y un análisis del contenido de las páginas web de 56 empresas relacionadas con el sector y cuestionarios, principalmenteSe han analizado empresas de EEUU, Canadá, España, Francia, Alemania, Reino Unido y Suiza

Sobre a primeira lei da termodinâmica: as diferenciais do calor e do trabalho

We treat some subtleties concerning the First Law of Thermodynamics and discuss the inherent difficulties, namely the interpretation of the heat and the work differentials. By proposing a new differential equation for the First Law, which is written using both system and neighborhood variables, we overcome the mentioned difficulties and establish a criterion for the definition of heat and work.

Determinação da diferença entre o valor real e o teórico do triglicerídeo ECN 42 para a detecção de adulteração em azeites de oliva comercializados no Brasil

The difference between the actual ECN 42 triacylglyceride content in vegetable oils, obtained by HPLC analysis, and the theoretical value calculated from the fatty acid composition was applied to detect the addition of seed oils with high contents of linoleic acid to olive oils commercialized in Brazil. The results indicate that samples analyzed were probably adulterated with low commercial value seed oils, rich in linoleic acid, like soybean, sunflower or corn.

Otimização dos parâmetros de produção de hidrolisados protéicos enzimáticos utilizando pescado de baixo valor comercial

The enzymatic modification of proteins has been widely studied with the aim of add value to low commercial value fish. The objective of this work was to evaluate and optimize the parameters involved in the production process of an enzymatic protein hydrolyzed with high protein content. The results showed that for Alcalase the most significant parameters were temperature, pH and substrate concentration and for Flavourzyme were pH, substrate concentration and enzyme concentration. It was obtained for Alcalase a predictive model for the recovered nitrogen and for Flavourzyme a predictive model for the hydrolysis degree.

A primeira lei da termodinâmica dos processos homogêneos

Thermodynamics of homogeneous processes, which corresponds to the very special situation in thermodynamics of continuous media, is used to discuss the first law. An important part of this work is the exposition of some typical mathematical errors, frequently found in the traditional presentation of thermodynamics. The concepts of state and process functions are discussed, as well as reverse and reversible processes, temporality and its implications on thermodynamics, energy reservoirs and symmetry. Our proposal is to present the first law by using a time dependent viewpoint coherent with mechanics and the foundations of that viewpoint.

Polissacarídeos da biodiversidade brasileira: uma oportunidade de transformar conhecimento em valor econômico

A brief comment about general characteristics of polysaccharide was presented. Brazilian trade of polysaccharides was obtained from the "Ministério de Desenvolvimento, Indústria e Comércio Exterior" - Brazil. A list of these products was prepared and their price and amount analyzed in the period of 1998-2007. Some chemical properties and application of polysaccharides from our biodiversity was described. In this review they were classified by origin, in vegetal (exudate, seed, fruit, seaweed), animal and bacteria source. There is a trade deficit that can be reverted if part of the accumulated scientific knowledge was used to promote the national economic development in the field.

Modificação química de argilas: desafios científicos e tecnológicos para obtenção de novos produtos com maior valor agregado

Chemical modification of clays is possible due to their ion-exchange and adsorption capacities, which allows the adjustment of the physicochemical properties of the surfaces of their layers. This modification makes possible the use of clays to produce a great number of new materials, which range from coarse applications such as oil based drilling fluids to refined applications such as pharmaceutical products. This article intends to expose where there is still space for research and investment aiming at the performance improvement of clay-based materials.

O valor energético dos alimentos: exemplo de uma determinação experimental, usando calorimetria de combustão

The energies involved in the combustion, under atmosphere of oxygen, of breakfast cereals and dehydrate powdered whole milk samples, were determined by combustion calorimetry. This practical work, in the field of human nutrition, involved the characterization of the nutritional composition and the combustion of samples of the two foods that are part of the alimentary diet, namely, at breakfast. The obtained results allowed to assess the energy value printed in the foods labels and discuss the way those values are estimated.

Um método verde, rápido e simples para determinar o valor energético de farinhas e cereais matinais

The Energy Value (EV) corresponds to the sum of the energetic contributions from food macronutrients (proteins, carbohydrates and fats) and is required on the labels of pre-packaged foods. The determinations of these parameters are based on distinct analytical procedures, each one being time-consuming, laborious and producing residues. This work presents multivariate models to determine the EV contents of industrialized foods for human consumption by using X-ray fluorescence spectra of samples with known parameters, determined through conventional methods. The proposed method is an alternative to conventional analytical methods and does not require any reagent, given the demands of the "green chemistry".

Aumento da resposta analítica por meio da otimização do sistema de injeção sem divisão de fluxo em cromatografia gasosa empregando a lei dos gases ideais

This paper reports the development of an easy, fast and effective procedure for the verification of the ideal gas law in splitless injection systems in order to improve the response. Results of a group of pesticides were used to demonstrate the suitability of the approach. The procedure helps establish experimental parameters through theoretical aspects. The improved instrumental response allowed extraction with lower sample volumes, the minimization of time and costs and the simplification of sample preparation.

A segunda lei da termodinâmica

Considering intrinsic characteristics of the system exclusively, both statistical and information theory interpretations of the second law are used to provide more comprehensive meanings for the concepts of entropy, temperature, and Helmholtz and Gibbs energies. The coherence of Clausius inequality to these concepts is emphasized. The aim of this work is to re-discuss the second law of thermodynamics in accordance to homogeneous processes thermodynamics, a temporal science which is the very special oversimplification of continuum mechanics for spatially constant intensive properties.

A importância da lei de Gay-Lussac para a classificação dos compostos orgânicos

This article shows the genesis of the law of volumes of combining gases, formulated by Gay-Lussac in 1808, and how it allowed the expression of the composition of organic compounds in terms of whole numbers of volumes, thus leading to the first classification of organic compounds, formulated by Dumas and Boullay in 1828. It was from this work that Organic Chemistry began to shed its purely taxonomic nature, analogous to what prevailed in Natural History, and to then develop in a vigorous and continuous process, initiating what may be the most significant historical phenomenon in the History of Chemistry of the nineteenth century.

Controle da ferrugem do cafeeiro com base no valor de severidade

O presente trabalho teve por objetivo avaliar o controle da ferrugem do cafeeiro (Coffea arabica) baseando-se no valor de severidade, calculado em função das variáveis meteorológicas, molhamento foliar e temperatura média durante o período de molhamento. Foram escolhidas duas lavouras de café da cultivar Catuaí Vermelho, uma com alta carga pendente de frutos (101,5 sacas beneficiadas/ha), com seis anos de idade, localizada no município de Coimbra, a 680 m de altitude, na região da Zona da Mata de Minas Gerais; e a outra, com carga média de frutos (22,4 sacas beneficiadas/ha), com nove anos de idade, localizada no município de Carmo do Paranaíba, a 850 m de altitude, na região do Alto Paranaíba do Estado de Minas Gerais. Em Coimbra, quando o valor de severidade da ferrugem (VSF) foi igual a 30, foram feitas duas pulverizações com fungicida sistêmico, igualando-se as duas aplicações de fungicida sistêmico do calendário. Em Carmo do Paranaíba, o VSF igual a 49 recomendou apenas uma única pulverização; todos os outros tratamentos demandaram duas aplicações de fungicidas sistêmicos. A incidência final de folhas doentes na colheita (11,0%) para todos os tratamentos, não atingiu o nível de dano econômico ao cafeeiro. Não houve diferença na eficiência de controle dos tratamentos baseados no calendário (duas aplicações de fungicidas sistêmicos e quatro aplicações de fungicida cúprico), duas aplicações de fungicida sistêmico baseadas na incidência da doença (10%) e o sistema baseado no VSF. Portanto, o sistema baseado no VSF foi tão eficiente quanto o calendário, para o controle da ferrugem do cafeeiro, porém com economia de uma pulverização, na lavoura com carga média de frutos (Carmo do Paranaíba).

Sobre o princípio e a lei universal do Direito em Kant

O artigo distingue duas fórmulas do princípio do Direito em Kant; mostra que na primeira delas o Princípio Universal do Direito é formulado como um principium diiudicationis e na segunda a Lei Universal do Direito como um principium executionis das ações conforme ao Direito; examina as dificuldades suscitadas para ambas as formulações, quais sejam, a base para a definição do que é direito e a questão se as leis jurídicas têm e, caso tenham, qual é a sua força prescritiva; e, finalmente, propõe uma solução baseada na consideração de que as leis jurídicas constituem para Kant uma subclasse das leis morais e se baseiam no conceito de uma autorização ou faculdade moral de fazer o que é moralmente lícito ou obrigatório e de não fazer o que é moralmente proibido.