Orbits and masses in the young triple system TWA 5

We aim to improve the orbital elements and determine the individual masses of the components in the triple system TWA 5. Five new relative astrometric positions in the H band were recorded with the adaptive optics system at the Very Large Telescope (VLT). We combine them with data from the literature and a measurement in the Ks band. We derive an improved fit for the orbit of TWA 5Aa-b around each other. Furthermore, we use the third component, TWA 5B, as an astrometric reference to determine the motion of Aa and Ab around their center of mass and compute their mass ratio. We find an orbital period of 6.03+/-0.01 years and a semi-major axis of 63.7+/-0.2 mas (3.2+/-0.1 AU). With the trigonometric distance of 50.1+/-1.8 pc, this yields a system mass of 0.9+/-0.1 Msun, where the error is dominated by the error of the distance. The dynamical mass agrees with the system mass predicted by a number of theoretical models if we assume that TWA5 is at the young end of the age range of the TW Hydrae association. We find a mass ratio of M_Ab / M_Aa = 1.3 +0.6/-0.4, where the less luminous component Ab is more massive. This result is likely to be a consequence of the large uncertainties due to the limited orbital coverage of the observations.Comment: 9 pages, 8 figures, accepted by Astronomy and Astrophysic

Uso de carvão como filtro para manipueira visando produção de fertilizante de liberação lenta.

Os subprodutos resultantes do processamento da mandioca têm sido grandes responsáveis por sérios problemas de contaminação do meio ambiente, poluindo solos e cursos de água doce. A manipueira é o resíduo líquido gerado pela prensagem das raízes nas indústrias de processamento de mandioca. A biomassa carbonizada (biochar) utilizada como filtro para resíduo líquido, a manipueira, possibilita a redução da carga poluente desse resíduo.PDF. 074_11

Construção de projetos sociais multidisciplinares: a disciplina projeto Rondon

Trabalho apresentado no II Congresso Nacional do PROJETO RONDON, realizado em Florianópolis, SC, no período de 23 a 25 de setembro de 2015 - Universidade Federal de Santa Catarina.Na reativação do Projeto Rondon em 2005, o MEC solicitou que as IES o reconhecessem institucionalmente e que promovessem atividades para sua sustentabilidade e aprimoramento. Em concordância e respeitando a autonomia das IES, o MD manifestou apoio na criação de eventos de extensão que pudessem vir a aprimorar e capacitar os participantes das IES. Em 2007 foi criada pelo Núcleo do Projeto Rondon, no âmbito do Decanato de Extensão da Universidade de Brasília, a disciplina “Formação teórica sobre a ação e concepção do Projeto Rondon”. O presente trabalho trata dos resultados da disciplina até o primeiro semestre de 2015. A metodologia para capacitar os futuros rondonistas incluiu a participação de um grupo de docentes de áreas diversas e a criação de uma sala virtual de apoio com o uso da Plataforma Moodle, além da oferta de turmas nos quatro campi. Os resultados mostraram que a discussão teórica sobre os modos de ação do Projeto Rondon proposto pela UnB capacitou tanto os alunos quanto os professores para ações de extensão. Além disso, apresentou a concepção do Projeto Rondon no que diz respeito a como ele é visto pelas Instituições Ministeriais de Ensino e Defesa, como também pelas Instituições de Ensino Superior. Nesse formato a disciplina foi ofertada até o segundo semestre de 2009 quando passou a ser denominada “Construção de Projetos Sociais Multidisciplinares” sendo ofertada como disciplina de graduação de módulo livre, cursada por alunos de qualquer um dos 78 cursos presenciais da UnB. A ementa tem a seguinte proposta: “Construção de projetos sociais com grupos multidisciplinares. Transformação de seus conhecimentos em ações multidisciplinares para o desenvolvimento e a capacitação de organizações da sociedade civil. Construção de projetos interdisciplinares nas áreas de Direitos Humanos e Justiça, Cultura, Comunicação, Educação, Saúde, Meio Ambiente, Tecnologia e Produção e Trabalho. Aplicação dos projetos em comunidades na área de abrangência da UnB.” Dados sobre oferta de vagas e matrículas efetivadas entre os anos de 2009 e 2012 revelam que a disciplina apresenta alta demanda, com 1.691 vagas ofertadas e 1.786 alunos efetivamente matriculados. Apenas no primeiro semestre de 2015 foram 173 alunos participantes das oito turmas nos quatro campi da UnB. A Disciplina atingiu 39 cursos (50% do total de cursos presenciais da UnB). Conclui-se que a condução da Disciplina tem impacto significativo no preparo dos rondonistas e futuros extensionistas

Bioinspired multilayer membranes as potential adhesive patches for skin wound healing

Bioinspired and adhesive multilayer membranes are produced using the layer-by-layer (LbL) assembly of chitosan (CHT), alginate (ALG) and hyaluronic acid modified with dopamine (HA-DN). Freestanding multilayer membranes without DN are also produced as a control. The success of the synthesis of HA-DN was confirmed using UV-visible spectroscopy. Scanning electron microscopy images indicate that the surface of the DN-containing membranes is more porous than the control ones; they also present a higher average thickness value for the same number of CHT/ALG/CHT/HA(-DN) tetralayers (n = 100). Also, water uptake, mechanical strength and adhesion are enhanced with the introduction of DN moieties along the nano-layers. Besides, human dermal fibroblast viability, enhanced adhesion and proliferation were confirmed by immunofluorescence assays and by measuring both the metabolic activity and DNA content. Moreover, in vivo assays with such kinds of DN-containing multilayer membranes were performed; the application of these membranes in the treatment of dermal wounds induced in Wistar rats results in the highest decrease of inflammation of rat skin, compared with the control conditions. Overall, this investigation suggests that these mussel-inspired freestanding multilayer membranes may enhance either their mechanical performance or cellular adhesion and proliferation, leading to an improved wound healing process, being a promising material to restore the structural and functional properties of wounded skin.M. P. S. acknowledges the Portuguese Foundation for Science and Technology (FCT) for financial support through Grant No. SFRH/BD/97606/2013. This work was supported by the European Research Council grant agreement ERC-2014-ADG-669858 for the ATLAS project. The authors acknowledge Paula Marques (Mechanical Engineering Department, University of Aveiro, Aveiro, Portugal) for providing the mechanical equipment to carry out the tensile tests and the lap shear adhesion tests.info:eu-repo/semantics/publishedVersio

Combined remediation technology for the reduction and bioleaching of hexavalent chromium from soils using Acidithiobacillus thiooxidans

Contamination of soils due to the release of effluents or deposition of wastes containing hexavalent chromium has been arising serious environmental problems. Therefore, the development of cost effectiveness but also ecological cleaning techniques is a matter of great concern among the scientific community. Bioremediation is attracting more and more attention due to its efficiency, low impact in the ecosystems and low cost. In particular, this study approaches a bioleaching technique using an Acidithiobacillus thiooxidans DSM504 pure culture to clean a soil contaminated with hexavalent chromium. Eight batch tests were performed in order to evaluate the effect of combined parameters: operational temperature (26ºC and Troom), hexavalent chromium concentration (50 mg kg-1 and 100 mg kg-1) and pH of the contaminant solution (2 and pHfree). The bioleaching technique herein exposed presented removal values between 33.3% and 83.3%, undergoing higher deviations due to changes on the contamination pH. Generally, it was more efficient when applied to soils contaminated with acid solutions. The lowest and highest values were both observed for operational temperatures of 26ºC and hexavalent chromium concentrations of 50 mg kg-1. Moreover, the highest value was observed for the soil contaminated with a hexavalent chromium solution of pH 2

Phytosociological surveys: tools for weed science?

Made available in DSpace on 2014-03-07T23:23:12Z (GMT). No. of bitstreams: 1 germaniplanta.pdf: 1437590 bytes, checksum: 2518af349217cec531443f69ffd935f2 (MD5) Previous issue date: 2013-11-08201

Palynological study of the endemic woody sonchus fron the flora of Madeira: a morphological and molecular approach

info:eu-repo/semantics/publishedVersio

ISO-LWS study of pre-main sequence sources

We present the results obtained with the ISO Long Wavelength Spectrometer on a sample of Pre-MS sources, where several molecular lines of CO, H2O and OH have been detected. The analysis of the CO lines indicates that gas temperatures as low as 200 K are consistent with the data. This would be in agreement with the relatively low abundance of water in the gas phase measured in most of the objects