MODELO INTERTEMPORAL DA CONTA CORRENTE: EVIDÊNCIAS PARA O BRASIL

The paper uses the procedure developed first by Campbell (1987) to test, for the Brazilian economy, the proposition that the balance of the current account is negatively related to the present value of the future changes of the GDP net of the investment and consumption of the government. Within the framework of intertemporal choice transitory shocks should affect the current account since the agents use credit or give loans in the international capital market to smooth the consumption pattern. On the contrary, when the shocks are permanent the agents adjust to a new consumption level and the effect on the current account is small. This means that the model should adjusts fairly well in countries with short run fluctuations. The empirical results of this work suggest that the present value of the future GDP path is able to explain the behavior of the quarter and annual Brazilian current account giving support to the model of intertemporal choice optimization.

Tecnologias de informação no suporte a um mercado de recursos para integração de empresas virtuais

Num ambiente de mercado altamente competitivo e global, as empresas procuram novos modelos de negócio e organizacionais com o objectivo de obterem vantagens competitivas e, dessa forma, sobreviverem. À mudança rápida e imprevisível dos requisitos do mercado, as empresas têm que responder com flexibilidade e dinamismo. O mercado, embora cada vez mais exigente, oferece também muitas oportunidades, fruto da diminuição do ciclo de vida dos produtos/serviços, da maior diversidade e da personalização. O modelo de Empresa Virtual e Ágil (E V/A), desenvolvido com base nestes pressupostos de mercado, propõe uma arquitectura flexível das organizações. A E V/A é uma empresa com capacidade de adaptação e reconfiguração em tempo útil, integrada a partir de empresas ou recursos independentes, com o objectivo de responder a uma oportunidade específica de mercado. Os recursos ou empresas estão interligados pelas tecnologias de informação para partilharem as suas aptidões chave, riscos e resultados num projecto comum. A criação, integração e operação da E V/A dependem de uma plataforma de tecnologias de informação e comunicação adequada. O ambiente de criação, integração, operação e dissolução de E V/A pode ser implementado sob a forma de Mercado de Recursos, entidade concebida para suportar a cobertura de todas as fases do ciclo de vida das E V/A. No mercado, diversos modelos de negócio existentes apresentam já muitas das características que descrevem o modelo E V/A e o Mercado de Recursos. Os mercados electrónicos implementam várias das funcionalidades identificadas no Mercado de Recursos; as tecnologias emergentes que tendem a ser consolidadas na implementação dos mercados electrónicos podem ser fundamentais na implementação do modelo de Mercado de Recursos. Com base na organização do Mercado de Recursos, ou seja, nos princípios gerais, processos, procedimentos e regras de funcionamento, e no estado da arte dos mercados electrónicos, foi desenvolvida uma arquitectura das tecnologias de informação de suporte ao Mercado de Recursos. Esta arquitectura define a plataforma tecnológica de integração para o funcionamento do Mercado de Recursos em todas as fases de vida das E V/A.To survive in the global and highly competitive market environment, enterprises search for new business and organisational models to gain competitive advantages. The enterprises have to answer dynamically and flexibly to the rapid and unpredictable change of the market requisites. Even the most demanding market environment hides many business opportunities. Nowadays, the reduction of the products/services life-cycle, the more diversity and the customisation offer new business opportunities. The Agile and Virtual Enterprise (A/V E) model, developed based on these assumptions, define flexible enterprise architecture. An A/V E is an enterprise with adaptation capacity and reconfigurability in useful time, integrated from enterprises or independent resources, with the aim to answer to a specific market opportunity. The resources or enterprises are connected by information technology in order to share their core competencies, risks and results from a common project. The A/V E creation, integration and operation, are supported by an appropriated information and communication technology platform. The Market of Resources is an entity developed to support A/V E from creation, integration, operation and dissolution environment. Many A/V E model and Market of Resources distinctive characteristics are common to existing business models. The electronic markets implemented several of the Market of Resources functionalities; emergent technologies that could be consolidated in the implementation of electronic markets could be the foundation to the Market of Resources implementation. It is proposed the information technologies architecture that supports the Market of Resources operation, which was developed based on the state of art of the electronic markets and on general principles, processes, procedures and operational rules of the Market of Resources. The information technologies architecture defines the technological integration platform for the operation of the Market of Resources in all the A/V E life-cycle phases

Elucidating the chemiexcitation of dioxetanones by replacing the peroxide bond with S-S, N-N and C-C bonds

Dioxetanone is one of the prototypical cyclic peroxide intermediates in several chemiluminescent and bioluminescent systems, in which thermolysis reactions allow efficient singlet chemiexcitation. While the chemiexcitation mechanism of dioxetanone and peroxide intermediates is still far from understood, the presence of a peroxide bond that undergoes bond breaking has been found to be a constant. Here we have addressed the following questions: can other non-peroxide bonds lead to chemiexcitation and, if not, can the differences between dioxetanone and non-peroxide derivatives help to elucidate their chemiexcitation mechanism? To this end, we have used a reliable TD-DFT approach to model the thermolysis and chemiexcitation of a model dioxetanone and its three other non-peroxide derivatives. The results showed that only the dioxetanone molecule could lead to chemiluminescence as it is the only one for which thermolysis is energetically favorable and provides a pathway for singlet chemiexcitation. Finally, the chemiexcitation of the model dioxetanone is explained by its access, during thermolysis, to a biradical region where the ground and excited states are degenerate. This occurs due to an increased interaction between the reaction fragments, which extends the biradical regions and delays the rupture of the peroxide ring

Combined Experimental and Theoretical Investigation into the Photophysical Properties of Halogenated Coelenteramide Analogs

Marine Coelenterazine is one of the most well-known chemi-/bioluminescent systems, and in which reaction the chemi-/bioluminophore (Coelenteramide) is generated and chemiexcited to singlet excited states (leading to light emission). Recent studies have shown that the bromination of compounds associated with the marine Coelenterazine system can provide them with new properties, such as anticancer activity and enhanced emission. Given this, our objective is to characterize the photophysical properties of a previously reported brominated Coelenteramide analog, by employing a combined experimental and theoretical approach. To better analyze the potential halogen effect, we have also synthesized and characterized, for the first time, two new fluorinated and chlorinated Coelenteramide analogs. These compounds show similar emission spectra in aqueous solution, but with different fluorescence quantum yields, in a trend that can be correlated with the heavy-atom effect (F > Cl > Br). A blue shift in emission in other solvents is also verified with the F-Cl-Br trend. More relevantly, the fluorescence quantum yield of the brominated analog is particularly sensitive to changes in solvent, which indicates that this compound has potential use as a microenvironment fluorescence probe. Theoretical calculations indicate that the observed excited state transitions result from local excitations involving the pyrazine ring. The obtained information should be useful for the further exploration of halogenated Coelenteramides and their luminescent properties

Supertubes in reduced holonomy manifolds

We show that the supertube configurations exist in all supersymmetric type IIA backgrounds which are purely geometrical and which have, at least, one flat direction. In other words, they exist in any spacetime of the form R^{1,1} x M_8, with M_8 any of the usual reduced holonomy manifolds. These generalised supertubes preserve 1/4 of the supersymmetries preserved by the choice of the manifold M_8. We also support this picture with the construction of their corresponding family of IIA supergravity backgrounds preserving from 1/4 to 1/32 of the total supercharges.Comment: 20 page

Toxicological Study Employing Repeated Doses of Garcinielliptone FC, a Polyisoprenylated-Benzophenone Isolated from Seed of Platonia Insignis Mart

The major constituent from the hexane extract of the seeds of P. insignis is GFC (garcinielliptone FC). Doses of 25, 50and 75 mg/kg of GFC were aseptically suspended in 0.05% Tween 80 dissolved in 0.9% saline (vehicle) and orally administered for30, 90 and 120 consecutive days to adult Swiss mice. In this work, the repeated oral administration, in animals of both sexes,demonstrates that this compound is not able to induce mortality and/or behavioral changes in adult mice. In addition, body weightgain, feed intake and disposal of excreta were not altered by the administration of this compound with repeated doses. Furthermore,no differences in weight and macroscopic structure of the brain, liver, kidney, lung, heart and spleen between groups of male andfemale adult mice were observed after treatment. During the periods of treatment, GFC produced no significant changes onhaematological and biochemical parameters in male and female mice treated with all doses used. The aim of this study was toinvestigate the toxicological potential of GFC through behavioral, hematological, biochemical and morphological parameters inanimals in order to ensure the safe use of Platonia insignis in folk medicine.Fil: Silva, Ana P.. Federal University of Piauí; BrasilFil: Filho, José Carlos C. L. S.. North Union of Parana; BrasilFil: da Costa Júnior, Joaquim S.. Federal Institute of Piauí; BrasilFil: Peláez, Walter José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Faillace, Martín Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Falcão Ferraz, Alexandre de B.. Lutheran University of Brazil; BrasilFil: David, Jorge M.. Institute Of Chemistry, Federal University Of Bahia; Brasil. Universidade Federal da Bahia; BrasilFil: Freitas, Rivelilson M.. Federal University of Bahia; Brasi

Investigation of the Anticancer and Drug Combination Potential of Brominated Coelenteramines toward Breast and Prostate Cancer

Cancer is a very challenging disease to treat, both in terms of therapeutic efficiency and harmful side effects, which continues to motivate the pursuit for novel molecules with potential anticancer activity. Herein, we have designed, synthesized, and evaluated the cytotoxicity of different brominated coelenteramines, which are metabolic products and synthesis precursors of the chemi-/bioluminescent system of marine coelenterazine. The evaluation of the anticancer potential of these molecules was carried out for both prostate and breast cancer, while also exploring their potential for use in combination therapy. Our results provided further insight into the structure-activity relationship of this type of molecule, such as their high structural specificity, as well highlighting the 4-bromophenyl moiety as essential for the anticancer activity. The obtained data also indicated that, despite their similarity, the anticancer activity displayed by both brominated coelenteramines and coelenterazines should arise from independent mechanisms of action. Finally, one of the studied coelenteramines was able to improve the profile of a known chemotherapeutic agent, even at concentrations in which its anticancer activity was not relevant. Thus, our work showed the potential of different components of marine chemi-/bioluminescent systems as novel anticancer molecules, while providing useful information for future optimizations

Space-time distribution of the ichthyofauna from Saco da Fazenda estuary, Itajaí, Santa Catarina, Brazil

Copyright © 2009 Coastal Education and Research Foundation (CERF).A Ictiofauna do estuário Saco da Fazenda foi estudada mensalmente entre julho de 2003 e junho de 2004 em quatro áreas definidas em função das características fisiográficas e da representatividade do estuário nesta região. Foram capturados 4502 exemplares, distribuídos em 42 espécies, 35 gêneros e 21 famílias. Engraulidae foram os peixes mais abundantes, onde Cetengraulis edentulus dominou nas capturas. As espécies de ocorrência ocasional, representadas, principalmente por indivíduos juvenis, predominaram nas amostragens. As maiores abundâncias ocorreram durante os meses de verão e outono, em contraste com as elevadas biomassas na primavera-outono; sendo que a área IV diferenciou-se das demais, por contribuir com as maiores capturas. Os índices de riqueza, diversidade e equitabilidade, apresentaram padrões semelhantes de flutuação, com valores elevados nos meses de primavera e verão. O índice de Jaccard revelou uma maior similaridade na composição da ictiofauna entre as áreas II e IV, enquanto a menor ocorreu entre I e IV, provavelmente devido às diferentes áreas destes locais.ABSTRACT: From July 2003 to June 2004, the physiographic characteristics of the ichthyofauna of the estuary of Saco da Fazenda were studied in four defined areas representative of the estuary. A total of 4502 individuals were captured, with 42 species, 35 genera, and 21 families. Engraulidae were the most abundant fish, and Cetengraulis edentulus dominated the captures. The species of occasional occurrence prevailed in the samplings and were represented mainly by juvenile individuals. The highest abundances occurred during the months of summer and autumn, in contrast with high biomasses in the spring and autumn; area IV contributed the largest captures. The richness indexes, diversity, and equitability presented similar flotation patterns, with high values in spring and summer. The Jaccard index revealed a greater similarity in the composition of the ichthyofauna in areas II and IV, while the lowest happened between I and IV, which is probably due to the different sizes of these areas. This paper clearly shows the relevance of this estuary, albeit strongly impacted, for recruitment of small fish mainly during summer and autumn months

Novel bilayered Gellan gum/Gellan gum hydroxyapatite scaffolds for osteochondral tissue engineering applications

Osteoarthritis is a major cause of disability during aging. By the age of 60, close to 100% of the population will have histologic changes of degeneration in their knee cartilage (Loeser, 2000). Because of its avascular nature, cartilage has little capacity to self-regenerate. Despite the progress already achieved in osteochondral regeneration, some limitations have to be overcome. The formation of fibrocartilage has to be avoided and the innervation has to be improved. Further, one main feature to be promoted is the induction of vascularization in the bony part but not in the cartilage part and to avoid de-differentiation processes. A promising strategy could pass through the development and optimization of novel culture systems. The ideal approach could integrate scaffolds presenting regions with different physical characteristics, combined with different growth factors to support different stem cells fates, regarding the complex tissue physiology to be regenerate. This work aims to develop novel bilayered gellan gum (GG)/gellan gumhydroxyapatite (HAp) hydrogels based structures for osteochondral tissue engineering applications. Bilayered GG/GG-HAp hydrogels were produced by joining both solutions of GG 2% (w/v) with and without HAp (20% wt.) for bony and cartilage parts, respectively. The solutions were introduced into a silicone mould with 20:10 mm (height and diameter, respectively). Gelation of GG was promoted by immersion in PBS solution for 24 h. The architecture of the bilayered scaffolds was investigated by micro-computed tomography. Results have shown that the freeze-dried bilayered scaffolds composed by low acyl GG(2%(w/ v)/low acyl GG(2%(w/v)-HAp20%(w/w) possess a porosity of 83.4 ± 0.8%, pore size of 279.3 ± 38.6 lm and interconnectivity of 62.2 ± 5.4%. Degradability assays are being performed with the intent to use this system to culture human adipose derived stem cells inducing cell co-differentiation into chondrocytes and osteoblasts. Ultimately, the developed bilayered scaffolds will provide new therapeutic possibilities for the regeneration of osteochondral defects