Imagem por Ressonância Magnética : uma ferramenta poderosa para a Engenharia de Tecidos. Uma revisão atualizada

A Engenharia de Tecidos (ET) é uma área de investigação crescente que se direciona à criação de substitutos biológicos funcionais para vários tecidos do corpo humano. Requer condições específicas favoráveis para a regeneração de tecidos, e o resultado do tecido engenheirado deve ser avaliado objetivamente. A Imagem por Ressonância Magnética (IRM) é uma das técnicas mais promissoras para este efeito. Esta revisão discute as publicações mais recentes acerca das várias técnicas baseadas na IRM disponíveis para a avaliação de tecidos engenheirados e as presentes aplicações da IRM na ET.

Carbon addition alters vegetation composition on ex-arable fields

1. Recent changes in European agricultural policy have led to measures to reverse the loss of species-rich grasslands through the creation of new areas on ex-arable land. Ex-arable soils are often characterized by high inorganic nitrogen (N) levels, which lead to the rapid establishment of annual and fast-growing perennial species during the initial phase of habitat creation. The addition of carbon (C) to the soil has been suggested as a countermeasure to reduce plant-available N and alter competitive interactions among plant species. 2. To test the effect of C addition on habitat creation on ex-arable land, an experiment was set up on two recently abandoned fields in Switzerland and on two 6-year-old restoration sites in the UK. Carbon was added as a mixture of either sugar and sawdust or wood chips and sawdust during a period of 2 years. The effects of C addition on soil parameters and vegetation composition were assessed during the period of C additions and 1 year thereafter. 3. Soil nitrate concentrations were reduced at all sites within weeks of the first C addition, and remained low until cessation of the C additions. The overall effect of C addition on vegetation was a reduction in above-ground biomass and cover. At the Swiss sites, the addition of sugar and sawdust led to a relative increase in legume and forb cover and to a decrease in grass cover. The soil N availability, composition of soil micro-organisms and vegetation characteristics continued to be affected after cessation of C additions. 4. Synthesis and applications. The results suggest that C addition in grassland restoration is a useful management method to reduce N availability on ex-arable land. Carbon addition alters the vegetation composition by creating gaps in the vegetation that facilitates the establishment of late-seral plant species, and is most effective when started immediately after the abandonment of arable fields and applied over several years.

Spatial and temporal effects of free-air CO2 enrichment (POPFACE) on leaf growth, cell expansion and cell production in a closed canopy of poplar

Leaf expansion in the fast-growing tree,Populus × euramericana was stimulated by elevated [CO2] in a closed-canopy forest plantation, exposed using a free air CO2 enrichment technique enabling long-term experimentation in field conditions. The effects of elevated [CO2] over time were characterized and related to the leaf plastochron index (LPI), and showed that leaf expansion was stimulated at very early (LPI, 0–3) and late (LPI, 6–8) stages in development. Early and late effects of elevated [CO2] were largely the result of increased cell expansion and increased cell production, respectively. Spatial effects of elevated [CO2] were also marked and increased final leaf size resulted from an effect on leaf area, but not leaf length, demonstrating changed leaf shape in response to [CO2]. Leaves exhibited a basipetal gradient of leaf development, investigated by defining seven interveinal areas, with growth ceasing first at the leaf tip. Interestingly, and in contrast to other reports, no spatial differences in epidermal cell size were apparent across the lamina, whereas a clear basipetal gradient in cell production rate was found. These data suggest that the rate and timing of cell production was more important in determining leaf shape, given the constant cell size across the leaf lamina. The effect of elevated [CO2] imposed on this developmental gradient suggested that leaf cell production continued longer in elevated [CO2] and that basal increases in cell production rate were also more important than altered cell expansion for increased final leaf size and altered leaf shape in elevated [CO2].

Long-term acclimation of leaf production, development, longevity and quality following 3 yr exposure to free-air CO2 enrichment during canopy closure in Populus

The effects of elevated CO2 on leaf development in three genotypes of Populus were investigated during canopy closure, following exposure to elevated CO2 over 3 yr using free-air enrichment.• Leaf quality was altered such that nitrogen concentration per unit d. wt (Nmass) declined on average by 22 and 13% for sun and shade leaves, respectively, in elevated CO2. There was little evidence that this was the result of ‘dilution’ following accumulation of nonstructural carbohydrates. Most likely, this was the result of increased leaf thickness. Specific leaf area declined in elevated CO2 on average by 29 and 5% for sun and shade leaves, respectively.• Autumnal senescence was delayed in elevated CO2 with a 10% increase in the number of days at which 50% leaf loss occurred in elevated as compared with ambient CO2.• These data suggest that changes in leaf quality may be predicted following long-term acclimation of fast-growing forest trees to elevated CO2, and that canopy longevity may increase, with important implications for forest productivity.

Real options and game theoretical approaches to real estate development projects: multiple equilibria and the implications of different tie-breaking rules

This paper contributes to a fast growing literature which introduces game theory in the analysis of real option investments in a competitive setting. Specifically, in this paper we focus on the issue of multiple equilibria and on the implications that different equilibrium selections may have for the pricing of real options and for subsequent strategic decisions. We present some theoretical results of the necessary conditions to have multiple equilibria and we show under which conditions different tie-breaking rules result in different economic decisions. We then present a numerical exercise using the in formation set obtained on a real estate development in South London. We find that risk aversion reduces option value and this reduction decreases marginally as negative externalities decrease.

The drivers of multinational enterprise subsidiary entrepreneurship in China: a new resource-based view perspective

This paper extends the resource-based view (RBV) of the firm, as applied to multinational enterprises (MNEs), by distinguishing between two critical resource dimensions, namely relative resource superiority (capabilities) and slack. Both dimensions, in concert with specific environmental conditions, are required to increase entrepreneurial activities. We propose distinct configurations (three-way moderation effects) of capabilities, slack, and environmental factors (i.e. dynamism and hostility) to explain entrepreneurship. Using survey data from 66 Canadian subsidiaries operating in China, we find that higher subsidiary entrepreneurship requires both HR slack and strong downstream capabilities in subsidiaries, subject to the industry environment being dynamic and benign. However, high HR slack alone, in a dynamic and benign environment, but without the presence of strong capabilities, actually triggers the fewest initiatives, with HR slack redirected from entrepreneurial experimentation towards complacency and inefficiency. This paper has major implications for MNEs seeking to increase subsidiary entrepreneurship in fast growing emerging markets.

Kundernas behov i butiksmiljöer : Skillnaderna mellan handlares och kunders uppfattning av kundernas behov i klädbutiker

Konkurrensen inom detaljhandeln blir allt hårdare, både från andra butiker men även från e-handeln, vilket sätter press på fysiska butiker att ha nöjda kunder som fortsätter handla i butiken. Ett tillvägagångssätt för att möta den hårdnande konkurrensen är att ha en butiksmiljö s.k. servicescape som är utformad efter kundernas behov, vilket dock förutsätter att handlarna vet vilka behov sina kunder har. Har handlarna en felaktig uppfattning om kundernas behov föreligger det ett gap som minskar chansen att kunderna blir nöjda och därmed butikens konkurrenskraft. En avgränsning gjordes till klädbutiker, då klädbutiker är bland de butikstyper som är mest konkurrensutsatt. Syftet med uppsatsen var att kartlägga hur kundernas behov överensstämmer eller skiljer sig från handlarnas uppfattning om deras behov. För att uppfylla syftet tillämpades en kvalitativ metod men med en statistisk bearbetning dvs. en kvantitativ bearbetning då resultatet redovisades med hjälp av frekvenser och värden på en skala. Datainsamlingsverktyget som användes var enkäter och utformades efter de tio faktorerna som sammanställdes i den teoretiska referensramen. Enkäterna delades ut till både kunder och handlare i Borlänges stadskärna och Faluns stadskärna. Resultatet av uppsatsen visade att det för faktorerna ljus (4,2), trängsel (4.5) (4.6), Ljud (4.7), toaletter (4.9), (4.10) finns en skillnad ett s.k. gap mellan handlarnas uppfattning om kundernas behov och vad kundernas behov egentligen är. Det framkom även att handlarna ansåg att kunderna har större behov av att faktorerna rent & städat (4.3), (4.4) in & utgångar (4.8) är tillfredsställande än vad kunderna egentligen har. Det framkom precis som behandlades i den teoretiska referensramen att kundernas behov tenderar att variera utifrån deras demografiska faktorer ålder och kön. Om handlarna har en låg, medel eller hög prisnivå påverkade även det hur viktigt det är för kunderna att faktorerna är tillfredsställande. Slutsatsen som författarna identifierade var att det föreligger ett gap mellan handlarnas uppfattning om kundernas behov och vad kunderna anser att deras behov är gällande flera av faktorerna. Detta är dock något som kunderna säger vilket inte behöver stämma överrens med hur de verkligen tycker. Det är dock svårt att urskilja något mönster gällande gapen utan det är nästan enbart tendenser man kan urskilja, vilket gör att varje faktor bör analyseras individuellt.

Uso do comércio eletrônico em órgãos do governo

O uso do comércio eletrônico está em expansão e tem fundamental relação com o rápido crescimento do uso da Internet e da Web. Apesar de estar se manifestando basicamente no âmbito das empresas privadas, o comércio eletrônico necessita de apoio governamental para que tenha um desenvolvimento consistente. Uma das formas de ação governamental para ajudar o desenvolvimento do comércio eletrônico é a sua utilização por parte dos próprios órgãos de governo. Este trabalho avalia o uso do comércio eletrônico em governos através de uma análise de Web sites municipais, estaduais e federais e também por uma investigação do Projeto de Governo Eletrônico no Governo do Estado de São Paulo.

Pharmaceutical patent bargains: the Brazilian experience

In the backdrop of the strict patent regime flatly adopted by the World Trade Organization (WTO) for all countries, a few countries constantly challenge this system through aggressive patent bargains. Within the pharmaceutical sector, noticeably, some countries now threaten to issue or otherwise actually issue compulsory licenses that may sway large pharmaceutical companies into selling drugs with large discounts or into granting voluntary licenses domestically. That is conspicuously the negotiation strategy adopted by Brazil in its negotiations with big international pharmaceutical companies.This paper explains Brazil’s aggressive bargaining approach based on an analysis of two aspects of its political economy. The first has to do with the international context of patent bargaining in the post-WTO era. Accordingly, the existence of large and fast growing domestic markets position countries such as Brazil as strategic destinations for Foreign Direct Investment (FDI) and trade. Together with an absence of a propensity to innovate in pharmaceutical products, these conditions boost Brazil’s bargaining power for issuing compulsory licenses over pharmaceutical products. The second aspect is related to political economy dynamics inside Brazil. Accordingly, the political framework in Brazil undermines long-term policies and favors short-sighted ones also vis-a-vis R&D investments in the pharmaceutical industry. This remains true regardless of the strictness of the patent regime in place. The lesson of Brazil is relevant arguably for other more powerful developing countries which presently examine Brazil's approach while further challenging the WTO's strict patent policy for the future.

Macroeconomia estruturalista do desenvolvimento

Structuralist development macroeconomics. This paper presents some basic ideas and models of a structuralist development macroeconomics (the tendencies to the overvaluation of the exchange rate and the tendency of wages to grow below productivity, the critique of growth with foreign savings, and a new model of the Dutch disease) that complement and actualize the thought of the Latin-American structuralist school that developed around ECLAC from the late 1940s to the 1960s. On the other hand, it suggests that a new national development strategy based on the experience of fast growing Asian countries is emerging; and argues that only the countries that adopt such strategy based on growth with domestic savings, fiscal and foreign trade responsibility and a competitive exchange rate will be able to catch up.

Structuralist macroeconomics and new developmentalism

This paper, first, presents some basic ideas and models of a structuralist development macroeconomics that complements and actualizes the thought of structuralist development economics that was dominant between the 1940s and the 1960s including in the World Bank. The new approach focus on the relation between the exchange rate and economic growth, and develops three interrelated models: the tendency to the overvaluation of the exchange, the critique of growth with foreign savings, and a model of the Dutch disease based on the existence of two exchange rate equilibriums: the “current” and the “industrial” equilibrium. Second, it summarizes “new developmentalism” – a sum of growth policies based on these models and on the experience of fast growing Asian countries

Oficiais da Marinha Mercante: um estudo sobre os fatores contribuintes para a evasão nos anos iniciais da carreira embarcada

A indústria de transporte marítimo brasileira passa por um momento de forte expansão decorrente, entre outros fatores, de políticas governamentais que incentivam a construção, nos estaleiros nacionais, de navios para serem utilizados em apoio às atividades da indústria de óleo e gás. Ao mesmo tempo, para complementar a frota brasileira, as empresas petroleiras demandam a contratação de grande quantidade de navios estrangeiros para apoiar as suas operações. Este quadro de crescimento da frota, observado, particularmente, nos últimos 10 anos, contrasta com a escassez de mão de obra qualificada para tripular as embarcações, de modo especial dos Oficiais da Marinha Mercante (OMM). Acentuando o contraste, o Conselho Nacional de Imigração editou a Resolução Normativa n° 72/2006, determinando às empresas de navegação, que operam barcos de bandeira estrangeira, a contratação de proporções mínimas de tripulantes brasileiros, após 90 dias contínuos de operação no país. Além disso, estudos encomendados pelo Sindicato dos Armadores, SYNDARMA, apontam que a taxa de evasão dos OMM, nos anos iniciais da carreira embarcada, é de cerca de trinta por cento. Assim, o presente estudo, a partir de uma revisão bibliográfica acerca da história da Marinha Mercante brasileira, da cultura brasileira, da motivação, dos conflitos família-trabalho, do trabalho em espaço confinado e da rotatividade, se desenvolveu em uma pesquisa exploratória e de campo, por meio de entrevistas pessoais, analisadas à luz da técnica da análise de conteúdo, com profissionais de reconhecida experiência com o tema, além de OMM, com o objetivo de identificar os fatores contribuintes para a evasão dos OMM nos anos iniciais da carreira embarcada. Como resultado, o estudo mostrou que os agentes motivadores intrínsecos e extrínsecos agem continuamente direcionando o comportamento dos OMM para a permanência ou saída da carreira embarcada. Nessa alternância de forças psicológicas e comportamentais, associadas à motivação, influenciam no processo decisório as alternativas existentes representadas pelas oportunidades de emprego oferecidas aos OMM, os conflitos trabalho-família e a dificuldade de adaptação ao trabalho em ambiente confinado. No caso dos OMM, do gênero feminino, a situação é ainda mais sensível, pois enfrentam dificuldades para conciliar a vida embarcada com o papel de mãe e esposa. Portanto, a motivação para a permanência ou saída da carreira embarcada está fortemente relacionada à busca pela realização das expectativas pessoais e ao desejo de equilibrar vida pessoal com a profissional.

Labor supply, risk aversion and economic refrom in China

Economic reform in China has created a small, but fast-growing private sector that has spurred rapid productivity growth. Growth of the private sector is predicated upon continued labor movements away from state-run industries and into private firms. This paper presents a theory of labor market sectoral choice demonstrating that three factors determine private sector labor supply-the difference in wages between the state and private sectors, private sector wage risk and risk aversion. Estimation of the model using survey data provides strong support for the theory. We find that the riskiness of private sector earnings has a greater effect in discouraging workers from taking jobs in private firms than the wage premi um has in attracting workers.

Growth, lipogenesis and body composition of piracanjuba (Brycon orbignyanus) fingerlings fed different dietary protein and lipid concentrations

Piracanjuba (Brycon orbignyanus) is a Brazilian migratory fast-growing omnivore, very appreciated as a sport fish, which is threatened to extinction in Southern Brazil due to stock over exploitation and dam building. Therefore, efforts have been made to raise this fish in captivity for reintroduction and aquaculture purposes. In the present study, the effects of different dietary protein and lipid concentrations on piracanjuba fingerlings growth performance, feed utilization, body composition, hepatosomatic index (HSI) and activity of the lipogenic enzymes fatty acid synthetase (FAS), glucose-6-phosphate dehydrogenase (G6PD) and malic enzyme (ME) were investigated using a 2 x 3 factorial experiment. Six casein-gelatin based diets were prepared combining two protein (30% and 32%) and three lipid concentrations (5.5%, 8.8% and 12.1%). Eleven fish, average weight 11.30 +/- 0.1 g, were held in each of 18 100-1 aquaria, supplied with recirculating freshwater. Each diet was randomly assigned to triplicate groups of fish and fed to apparent satiation, twice a day for 100 d. Piracanjuba fingerlings' daily weight gain (0.36-0.40 g), specific growth rate (1.43-1.51%), feed utilization and HSI were not influenced by dietary protein or lipid concentration. However, body composition was directly affected by dietary treatment. An increase in body fat and dry matter was observed as dietary lipid increased, for both dietary protein concentrations tested. The activity of FAS was depressed by increasing dietary fat levels but the G6PD activity did not differ among dietary treatments, although ME activity showed some regulation by dietary protein. These results indicate that an increase from 5.5% to 12.1% in the dietary lipid, at a dietary protein concentration of 30% or 32%, promotes body fat accumulation in piracanjuba fingerlings with no improvement in growth, suggesting that the lipid requirement for this species should be 5% or less, when raised for commercial purposes. However, the additional energy reserve from body fat accumulation could be desirable for piracanjuba fingerlings produced for stock enhancement. (C) 2003 Editions scientifiques et medicales Elsevier SAS and Ifremer/IRD/Inra/Cemagref. All rights reserved.

Population structure of pond-raised Macrobrachium amazonicum with different stocking and harvesting strategies

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)