5,009 research outputs found

    Recuperação de Mata Ciliar em Ouro Preto do Oeste, estado de Rondônia, Brasil.

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    Este trabalho foi realizado na bacia do rio Boa Vista localizada no município de Ouro Preto do Oeste, Rondônia, com o intuito de avaliar o desenvolvimento de um plantio de espécies arbóreas na área de mata ciliar. A recuperação desta bacia se deu mediante acordos firmados entre o poder público Estadual e a sociedade envolvida, a partir daí vários produtores se engajaram no projeto, visto que o rio é muito importante na região e também é fonte de captação da água que abastece a cidade. Foi observado a área de um produtor envolvido neste processo. No caso em estudo foram encontradas 13 espécies, 11 famílias e 92 indivíduos plantados e nativos, com grande chance de sobrevivência nas parcelas.Resumos do VIII Congresso Brasileiro de Agroecologia. Porto Alegre/RS - 25 a 28/11/2013. Trabalho n. 14816

    Temperature dependence of surface stress across an order-disorder transition: p(1x2)O/W(110)

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    Strain relaxations of a p(1x2) ordered oxygen layer on W(110) are measured as a function of temperature across the disordering transition using low-energy electron diffraction. The measured strains approach values of 0.027 in the [1-10] and -0.053 in the [001] direction. On the basis of the measured strain relaxations, we give quantitative information on temperature-dependent surface stress using the results of ab initio calculations. From the surface formation energy for different strains, determined by first-principles calculations, we estimate that surface stress changes from -1.1 for the ordered phase to -0.2N/m for the disordered one along [1-10], and from 5.1 to 3.4 N/m along [001]. Moreover, our observation that the strains scale inversely with domain size confirms that the strain relaxation takes place at the domain boundaries.Comment: 8 pages, 5 figure

    Project Manager and Systems Engineer: a literature rich reflection on roles and responsibilities

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    There are several definitions of Systems Engineering (SE) in the literature, each with different definitions of its relationship with Project Management (PM), causing a great deal of misunderstanding. The paper offers a broad and critical discussion of the relevant literature with a deep reflection concerning the historical evolution and state-of-the-art of both the definition of SE and its relationship with PM. This endeavor provides two main results: (i) a conceptual framework to define SE in a project based environment and (ii) a model to identify the best formal interaction between the Project Manager and System Engineer based on the project characteristics

    Modulation of microRNA editing, expression and processing by ADAR2 deaminase in glioblastoma.

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    Background: ADAR enzymes convert adenosines to inosines within double-stranded RNAs, including microRNA (miRNA) precursors, with important consequences on miRNA retargeting and expression. ADAR2 activity is impaired in glioblastoma and its rescue has anti-tumoral effects. However, how ADAR2 activity may impact the miRNome and the progression of glioblastoma is not known. Results: By integrating deep-sequencing and array approaches with bioinformatics analyses and molecular studies, we show that ADAR2 is essential to edit a small number of mature miRNAs and to significantly modulate the expression of about 90 miRNAs in glioblastoma cells. Specifically, the rescue of ADAR2 activity in cancer cells recovers the edited miRNA population lost in glioblastoma cell lines and tissues, and rebalances expression of onco-miRNAs and tumor suppressor miRNAs to the levels observed in normal human brain. We report that the major effect of ADAR2 is to reduce the expression of a large number of miRNAs, most of which act as onco-miRNAs. ADAR2 can edit miR-222/221 and miR-21 precursors and decrease the expression of the corresponding mature onco-miRNAs in vivo and in vitro, with important effects on cell proliferation and migration. Conclusions: Our findings disclose an additional layer of complexity in miRNome regulation and provide information to better understand the impact of ADAR2 editing enzyme in glioblastoma. We propose that ADAR2 is a key factor for maintaining edited-miRNA population and balancing the expression of several essential miRNAs involved in cancer

    Biomassa e teores de nutrientes da serrapilheira e caracterização do solo em sistema agroflorestal de castanheira-do-brasil e cupuaçuzeiro em Porto Velho, Rondônia.

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    O objetivo deste trabalho foi avaliar a produção de serrapilheira e nutrientes presentes na mesma e no solo em um sistema agroflorestal de castanheira-do-brasil e cupuaçuzeiro, em Porto Velho, Rondônia

    Stress engineering at the nanometer scale: Two-component adlayer stripes

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    Spontaneously formed equilibrium nanopatterns with long-range order are widely observed in a variety of systems, but their pronounced temperature dependence remains an impediment to maintain such patterns away from the temperature of formation. Here, we report on a highly ordered stress-induced stripe pattern in a two-component, Pd-O, adsorbate monolayer on W(110), produced at high temperature and identically preserved at lower temperatures. The pattern shows a tunable period (down to 16 nm) and orientation, as predicted by a continuum model theory along with the surface stress and its anisotropy found in our DFT calculations. The control over thermal fluctuations in the stripe formation process is based on the breaking/restoring of ergodicity in a high-density lattice gas with long-range interactions upon turning off/on particle exchange with a heat bath.Comment: 6 pages, 4 figure

    Efficiency of transient transformation in tobacco protoplasts is independent of plasmid amount

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    An optimized protocol for the transient transformation of tobacco protoplasts mediated by polyethylene\u2013glycol (PEG) is here described. As expected, the quantitative b\u2013glucuronidase (Gus) activity driven by pCaMVGus was dependent on the amount of plasmid used. Nevertheless, we demonstrate by an immunodetection method that transformation efficiency did not depend on the amount of plasmid used but on the limitation imposed by cell competence. In fact, we obtained the same percentage of transformed cells (about 60%) using a wide range of plasmid concentrations (0.1\u201310 mg per test). Finally, we show that, when we used two plasmid types in a mixture at a concentration ranging from 0.1 to 10 mg for each, all transformed cells expressed proteins encoded by both plasmids. Transient expression and co-transformation experiments are routinely used methods and, probably, the major results from this work were assumed by many researchers in this field, but our data experimentally support this assumption

    Analysis of some global optimization algorithms for space trajectory design

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    In this paper, we analyze the performance of some global search algorithms on a number of space trajectory design problems. A rigorous testing procedure is introduced to measure the ability of an algorithm to identify the set of ²-optimal solutions. From the analysis of the test results, a novel algorithm is derived. The development of the novel algorithm starts from the redefinition of some evolutionary heuristics in the form of a discrete dynamical system. The convergence properties of this discrete dynamical system are used to derive a hybrid evolutionary algorithm that displays very good performance on the particular class of problems presented in this paper
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