A phorbol ester-binding protein is required downstream of Rab5 in endosome fusion

AbstractPrevious observations indicate that a zinc and phorbol ester binding factor is necessary for endosome fusion. To further characterize the role of this factor in the process, we used an in vitro endosome fusion assay supplemented with recombinant Rab5 proteins. Both zinc depletion and addition of calphostin C, an inhibitor of protein kinase C, inhibited endosome fusion in the presence of active Rab5. Addition of the phorbol ester PMA (phorbol 12-myristate 13-acetate) reversed the inhibition of endosome fusion caused by a Rab5 negative mutant. Moreover, PMA stimulated fusion in the presence of Rab5 immunodepleted cytosol. These results suggest that the phorbol ester binding protein is acting downstream of Rab5 in endosome fusion

The Infrared Counterpart of the X-ray Burster KS 1731--260

We present JK' infrared images of the X-ray transient KS 1731--260, obtained in 1997 and in 1998 with IRAC2b at the ESO/MPI 2.2-m telescope at La Silla. Using as a reference the recent Chandra position, we confirm the identification of the X-ray source with the previously proposed counterpart (Wijnands et al. 2001b), for which we measure J=17.32 +/- 0.2 and K' = 16.36 +/- 0.18. The source was entering a low X-ray state at the epoch of our observations, and the accretion disk was still dominating the infrared flux. Indeed, when compared with the only published magnitudes in the J-band (Orosz et al. 2001), obtained with the source in quiescence, our photometry confirms the fading of the counterpart during the decay of the RXTE/ASM lightcurve.Comment: 4 pages, LaTex, 5 Postscript figures. Astronomy & Astrophysics Letter, accepte

Giant natural optical rotation from chiral electromagnons in a collinear antiferromagnet

In NiTe$_3$O$_6$ with a chiral crystal structure, we report on a giant natural optical rotation of the lowest-energy magnon. This polarization rotation, as large as 140 deg/mm, corresponds to a path difference between right and left circular polarizations that is comparable to the sample thickness. Natural optical rotation, being a measure of structural chirality, is highly unusual for long-wavelength magnons. The collinear antiferromagnetic order of NiTe$_3$O$_6$ makes this giant effect even more peculiar: Chirality of the crystal structure does not affect the magnetic ground state but is strongly manifested in the lowest excited state. We show that the dynamic magnetoelectric effect, turning this magnon to a magnetic- and electric-dipole active hybrid mode, generates the giant natural optical rotation. In finite magnetic fields, it also leads to a strong optical magnetochiral effect.Comment: 9 pages, 4 figure

Produção de biomassa e CO2 equivalente em sistema agrossilvipastoril: uma aplicação da dinâmica de sistema.

Resumo: Os Sistemas Agroflorestais (SAFs) mostram-se como uma alternativa social e econômica às consequências da ação antrópica sobre o meio ambiente. Buscou-se verificar a dinâmica da produção de biomassa e o estoque de CO2 equivalente no SAF, em área de caatinga no estado do Ceará. A área de estudo compreendeu o SAF localizado na Fazenda Crioula, pertencente ao Centro Nacional de Pesquisa de Caprinos da Embrapa, estando situada no município de Sobral, CE. Utilizou-se como ferramenta de elaboração do modelo o software Vensim®. As simulações basearam-se na determinação de cenários para uso da terra (culturas agrícolas) e manejo da caatinga. Os resultados demonstraram que o sistema foi capaz agregar renda por meio da venda dos produtos agrícolas e a comercialização do CO2 equivalente caso existisse um mercado específico para o produtor. O modelo desenvolvido para SAF oriundo desta pesquisa mostrou-se capaz de contribuir com as pesquisas já desenvolvidas atualmente, bem como para a sustentabilidade e viabilidade desse modelo de produção, por meio da diversificação de atividades e produtos, favorecendo uma geração de renda mais harmônica no tempo. [Estimated of biomass and CO2 equivalent by an agrosilvopastoral system: through the system dynamics]. Abstract: Agroforestry Systems (SAF) are shown as an alternative to social and economic consequences of human action on the environment. We sought to determine the dynamics of biomass production and the stock of CO2 equivalent in the SAF, in an area of "caatinga" biome in the state of Ceará. The study area comprised the SAF in Crioula farm, belonging to the National Research Center of Embrapa Goats, being situated in the municipality of Sobral - CE. It was used as a tool for developing the model the software Vensim. The simulations were based on the determination of option settings land uses (agricultural crops) and management of ?caatinga?. The results showed that the system was able to add income by selling agricultural products and the commercialization of CO2 equivalent if there were a specific market for this producer. The model developed for this research come from SAF was able to contribute to the research already carried out today as well as to the sustainability and viability of this model of production through diversification of activities and products, promoting a more harmonious income generation in time.Edição dos Resumos do VII Congresso Brasileiro de Agroecologia, Fortaleza, CE, 12 a 16 dez. 2011

Valoração econômica dos serviços ambientais em um sistema agrossilvipastoril no bioma caatinga.

Resumo: No intuito de minimizar os impactos da ação antrópica sobre o bioma Caatinga, a Embrapa Caprinos e Ovinos desenvolveu um sistema agroflorestal (SAF) para o semiárido que oferece benefícios ao sistema produtivo bem como serviços ambientais. O objetivo deste trabalho foi valorar o serviço ambiental - sequestro de carbono, gerado por um SAF localizado em Sobral/CE. Para isso, foram desenvolvidos os índices de contribuição (IC), o custo de oportunidade das atividades agropecuárias desenvolvidas na agricultura familiar do Ceará (CO) e a construção do índice-ponto (IP) obtido na área. A valoração foi feita pela multiplicação entre o IP e o CO indexado à Unidade Fiscal de Referência do Ceará (UFIRCE). O custo de oportunidade foi de R$878,36. O SAF obteve índice-ponto igual à 5.4, equivalente ao valor de R$ 4.743,82, sendo o valor de R$592,98 quando avaliado por hectare. A metodologia de valoração econômica proposta se mostrou eficiente e eficaz em responder ao objetivo da pesquisa e serve como base para um processo de pagamento pelos serviços ambientais (PSA) [Economic valuation of environmental services on a agrossilvipastoral system of “caatinga” biome]. In order to minimize the impacts of human action on the “Caatinga” biome, Embrapa developed a agroforestry system (SAF) for semi arid areas that provide benefits to the productive system and environmental services. The objective of this study was to find a value for environmental services - carbon sequestration, generated by a SAF located in Sobral, CE. Thus, were developed contribution rates (IC), the opportunity cost of agricultural activities developed in family farming in Ceará (CO) and the construction of the index-point (IP) obtained in the area. The valuation was done by multiplying the IP and CO indexed to the Fiscal Reference Unit of Ceará (UFIRCE). The opportunity cost was U$535.9. This index obtained SAF-point equal to 5.4, equivalent to U$2892.57, and the value of U$361.57 when measured per hectare. The economic valuation methodology proposed is efficient and effective in responding to our research and serves as the basis for a process of payment for environmental services (PES

A major star formation region in the receding tip of the stellar Galactic bar

We present an analysis of the optical spectroscopy of 58 stars in the Galactic plane at $l=27$\arcdeg, where a prominent excess in the flux distribution and star counts have been observed in several spectral regions, in particular in the Two Micron Galactic Survey (TMGS) catalog. The sources were selected from the TMGS, to have a $K$ magnitude brighter than +5 mag and be within 2 degrees of the Galactic plane. More than 60% of the spectra correspond to stars of luminosity class I, and a significant proportion of the remainder are very late giants which would also be fast evolving. This very high concentration of young sources points to the existence of a major star formation region in the Galactic plane, located just inside the assumed origin of the Scutum spiral arm. Such regions can form due to the concentrations of shocked gas where a galactic bar meets a spiral arm, as is observed at the ends of the bars of face-on external galaxies. Thus, the presence of a massive star formation region is very strong supporting evidence for the presence of a bar in our Galaxy.Comment: 13 pages (latex) + 4 figures (eps), accepted in ApJ Let

Design S-N curves for old Portuguese and French riveted bridges connection based on statistical analyses

Maintenance of ancient road and railway metallic bridges has become a major concern for governmental agencies in the past few decades. Indeed, since the construction of these structures, between the end of the 19th century and the beginning of the 20th century, traffic conditions have evolved, both in weight and frequency. In the purpose to assess the remaining life of old metallic bridges, some critical structural details have been identified and associated to S-N curves in order to be used in damage estimation (using Palmgren-Miner’s rule for cumulative damage, for example). These constructional details are described by design rules of several European and North American standards, such as the Eurocode 3, BS 5400 and AASHTO standards. The particularity of ancient bridges is that hot riveted assemblies, commonly used for their construction, are not represented in most construction standards. Further experiences on the matter by numerous research teams have suggested detail category C71 from the Eurocode 3 as appropriate. In this paper, experimental data from double shear assemblies manufactures from three different metallic ancient bridges is used to identify, through a statistical analysis, the S-N curves that best fit this constructional detail. Portuguese and French puddled iron bridges were considered.The authors of this paper thank the National Society of French Railways and the SciTech - Science and Technology for Competitive and Sustainable Industries, R&D project NORTE-01-0145-FEDER-000022 cofinanced by Programa Operacional Regional do Norte ("NORTE2020"), through Fundo Europeu de Desenvolvimento Regional (FEDER) for their collaboration and support during this research works. The authors also acknowledge the Portuguese Science Foundation (FCT) for the financial support through the post-doctoral grant SFRH/BPD/107825/2015