V-ATPase Proton Pumping Activity Is Required for Adult Zebrafish Appendage Regeneration

JJM was supported by a fellowship (SFRH/BD/45131/2008) from Fundacao para a Ciencia e Tecnologia (FCT), Portugal. ACC was supported by a postdocoral fellowship (SFRH/BPD/29957/2006) from Fundacao para a Ciencia e Tecnologia (FCT), Portugal. This work was supported by the following grants: european FP6-Cells into Organs, FCT (Grant PTDC/BIA-BCM/100867/2008 and POCTI-ISFL-4-664) and Ministerio de Ciencia e Innovacion, Spain (Subprograma Ramon y Cajal, reference RYC-2008-02753 and grant BFU2009-12279). JRL is supported by the Subprogram Ramon y Cajal from Ministerio de Ciencia e Innovacion, Spain (RYC-2008-02753). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.The activity of ion channels and transporters generates ion-specific fluxes that encode electrical and/or chemical signals with biological significance. Even though it is long known that some of those signals are crucial for regeneration, only in recent years the corresponding molecular sources started to be identified using mainly invertebrate or larval vertebrate models. We used adult zebrafish caudal fin as a model to investigate which and how ion transporters affect regeneration in an adult vertebrate model. Through the combined use of biophysical and molecular approaches, we show that V-ATPase activity contributes to a regeneration-specific H+ ef'flux. The onset and intensity of both V-ATPase expression and H+ efflux correlate with the different regeneration rate along the proximal-distal axis. Moreover, we show that V-ATPase inhibition impairs regeneration in adult vertebrate. Notably, the activity of this H+ pump is necessary for aldh1a2 and mkp3 expression, blastema cell proliferation and fin innervation. To the best of our knowledge, this is the first report on the role of V-ATPase during adult vertebrate regeneration.publishe

Doing Science: How to optimise patient and public involvement in your research

This paper considers how best to achieve patient and public involvement in research and how to get the most out of it http://ow.ly/R0hwV

Doing Science: How to optimise patient and public involvement in your research

This paper considers how best to achieve patient and public involvement in research and how to get the most out of it http://ow.ly/R0hw

Global Biofuel Expansion and the Demand for Brazilian Land: Intensification versus Expansion

We use a spatially disaggregated model of Brazilian agriculture to assess the implications of global biofuel expansion on Brazilian land usage at the regional level. This Brazilian model is part of the FAPRI agricultural modeling system, a multimarket, multi-commodity international agricultural model, used to quantify the emergence of biofuels and to analyze the impact of biofuel expansion and policies on both Brazilian and world agriculture. We evaluate two scenarios in which we introduce a 25% exogenous increase in the global demand for ethanol and one scenario in which we increase global ethanol demand by 50%. We then analyze the impact of these increases in terms of land-use change and commodity price changes particularly in Brazil. In the first scenario, we assume that the enforcement of the land-use reserve in Brazil remains at historically observed levels, and that abundant additional land can be readily incorporated into production. The second scenario involves implementing the same exogenous biofuel demand shock but with a different responsiveness in area expansion to price signals in Brazil, reflecting varying plausible assumptions on land availability for agricultural expansion. The third scenario, which is similar to the first scenario but with a larger increase in global ethanol demand, is run to check whether increasing volume of ethanol requires the incorporation of additional quantities of land per unit of ethanol. We find that, within Brazil, the expansion occurs mostly in the Southeast region. Additionally, total sugarcane area expansion in Brazil is higher than the increase in overall area used for agriculture. This implies that part of the sugarcane expansion displaced other crops and pasture that is not replaced, which suggests some intensification in land use. The lower land expansion elasticities in the second scenario result in a smaller expansion of area used for agricultural activities. A higher proportion of the expansion in sugarcane area occurs at the expense of pasture area, which implied land intensification of beef production. This explains the small change in commodity prices observed between the first and second scenarios. These results suggest that reducing the overall responsiveness of Brazilian agriculture may limit the land-use changes brought about by biofuel expansion, which would in turn reduce its environmental impacts in terms of land expansion. Additionally, the impacts on food prices are limited because of the ability of local producers to increase the intensity of land use in both crop (by double cropping and raising yields) and livestock production (by increasing the number of heads of cattle per hectare of pasture or stocking rate) releases area that can be used for crops. In scenario three, we find that larger ethanol volumes did not require more land per unit of ethanol. Doubling the demand for ethanol does not change the results, which indicates that the limit for intensification is beyond the 50% expansion assumed in Scenario 3. In this range, the same amount of land is incorporated into production per additional unit of ethanol.Biofuels, Brazil, land use, Land Economics/Use,

Influência da raça na qualidade de couros caprinos

O estudo foi conduzido com o objetivo de avaliar a influência da raça na qualidade de couros caprinos. Foram utilizados cinco caprinos de cada uma das raças: Anglo Nubiana, Alpina e Saanen, com seis meses de idade. Os animais foram abatidos e as peles foram curtidas ao cromo e recurtidas com recurtente acrílico. Dos couros foram retiradas três amostras na posição paralela e três na perpendicular à linha dorsal para a avaliação da qualidade intrínseca de resistência à tração, ao rasgamento e ao lastômetro. As médias dos resultados foram comparadas pelo teste de Tukey ao nível de 5% de probabilidade. A raça não influenciou a resistência à distensão da superfície dos couros dos animais estudados no teste de lastômetro. As médias da resistência dos couros à tração foram maiores na posição longitudinal (P&#61500;0,05) para as três raças. Na posição longitudinal os couros dos caprinos Anglo Nubianos foram mais resistentes à tração (P<0,05), comparado com os couros das outras duas raças, que não apresentaram diferença entre si. A resistência dos couros ao rasgamento não sofreu influência da posição, porém na posição transversal os couros dos caprinos Anglo Nubianos foram mais resistentes (P<0,05), comparado com os couros das outras duas raças, que não apresentaram diferença entre si. A raça e a posição de retirada das amostras de couro influenciam a qualidade de couros caprinos

Convenções para Eliminar a Dupla Tributação

Quais as Convenções para Eliminar a Dupla Tributação

Linear and nonlinear models for the analysis of the relationship between stock market prices and macroeconomic and financial factors

The main objective of this paper is to assess how mutual information as a measure of global dependence between stock markets and macroeconomic factors can overcome some of the weaknesses of the traditional linear approaches commonly used in this context. One of the advantages of mutual information is that it does not require any prior assumption regarding the specification of a theoretical probability distribution or the specification of the dependence model. This study focuses on the Portuguese stock market where we evaluate the relevance of the macroeconomic and financial variables as determinants of the stock prices behaviour.nonlinear dependence, stock market, financial and macroeconomic factors