469 research outputs found

    Functional analysis of the mouse Nodal antagonist, Cerl2, during left-right axis formation

    Get PDF
    Although recently our understanding of how the LR asymmetry is generated in vertebrate embryos has seen rapid progress, many important questions remain to be explained. In mouse embryos, the leftward flow of the extra-embryonic fluid in the node cavity, called nodal flow, seems to be the symmetry-breaking event. However, it is not yet know how this flow functions or how the asymmetric signal(s) generated in the node is/are transferred to the lateral plate mesoderm. The mouse gene cerberus-like2(cerl2) encodes a 20-kDa protein with a predicted signal peptide sequence and a cysteine-rich domain (CRD) containing nine cysteines characteristic of the Cerberus/DAN family. Whole-mount in situ hybridization studies showed that cerl2 transcripts could be first detected in a horseshoe-shaped expression pattern in the perinodal region of the mouse embryo (E7.0), resembling Nodal expression at this stage. At stage E7.5, expression of cerl2 begins to decrease in intensity on the left side, and by early somitogenesis (E8.0), it can be strongly detected in the right side of the node, assuming a complementary expression pattern to that observed in Nodal. Furthermore, it was shown that Cerl2 activity is upstream of the Nodal receptor inhibiting Nodal and its downstream targets. A physical interaction between these two proteins exists, which suggests that Cerl2 is a secreted Nodal antagonist. Here, to elucidate the role of Cerl2 protein in the early events of symmetry breaking the functional activity of this Nodal antagonist will be discussed.info:eu-repo/semantics/publishedVersio

    Herbage Characteristics as Affected by the Canopies of Dominant Trees in a Savanna of Southern Mozambique

    Get PDF
    This study surveyed the species composition, forage yield and forage nitrogen concentration of the herbaceous layer 50, 100 and 200% of the canopy radius from the trunks of many-stemmed false thorn, knob thorn, scented thorn and marula trees in a southern Mozambican savanna. Tree species did not affect herbaceous DM yield or species diversity. Neither direction nor distance from the tree trunk affected DM or specific diversity. Crude protein percentages were 15% higher for legumes and 9% higher for grasses at 50% canopy than at 200% canopy. Grasses under the marulas, the only non-legume tree in the study, had 18% lower CP than the average for the other three tree species. Green panic was the predominant grass species under the canopies while no single grass species predominated outside the canopy where common urochloa, Themeda triandra and Aristida spp. were the most common grasses. Vigna spp. and Stylosanthes fruticosa were evenly distributed whereas Tephrosia spp. was found predominantly outside the canopy

    Saturnus: Um Simulador Discreto Baseado em Eventos para Sistemas de Arquivos Paralelos

    Get PDF
    The focus of this work is to study parallel file systems, their elements and present Saturnus, a simulator under development for systems like these. The proposal is to use it to extract data and generate information, focusing on load balancing through the studied environment, showing experiments and possible uses for the tool. (O foco desse trabalho e ́ estudar sistemas de arquivos paralelos, seus elementos e apresentar o Saturnus, um simulador em desenvolvimento para sistemas como esses. A proposta consiste em utilizar o mesmo para extrair dados e gerar informacoes, com foco no balanceamento de carga atrave ́s do ambiente estudado, mostrando experimentos e poss ́ıveis usos para a ferramenta.

    The isotopic composition (d15N, d13C) of agricultural wastes and derived composts.

    Get PDF
    The aim of this study was to measure variations in the isotopic composition (d13C and d15N) during the composting of different agricultural wastes using bench-scale bioreactors. Four different feedstocks of agricultural wastes (Horse bedding manure + legumes residues; Dairy manure + Jatropha mill cake; Dairy manure + sugarcane residues; Dairy manure) were used for aerobic-thermophilic composting. During composting no significant differences were found between the d13C values of the source material and the compost, except for Dairy manure + sugarcane residues. d15N values increased significantly in composts of Horse bedding manure + legumes residues and Dairy manure + Jatropha mill cake. d15N values of composts may be related to NH3 volatilization during the composting process. Isotopic signatures (d13C, d15N) can be used to differentiate composts from different feedstock sources and d15N values may be a quantitative indicator of NH3 volatilization during composting. Use of bench-scale bioreactors is a promising apparatus to study the dynamics of C and N and stable isotopes signatures during composting, but future adjustments regarding sampling methodology are necessary

    Light Art : light as matter in artistic work

    Get PDF
    Orientador: José Eduardo Ribeiro de PaivaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de ArtesResumo: Esta pesquisa tem como tema a luz como matéria do fazer artístico, e seu objetivo é analisar e entender como objetos luminosos são transformados em obras artísticas. Para tanto, fazemos uma análise sintética do entendimento do que é a luz, pelo viés da filosofia e das ciências. Depois, tratamos da história do uso tridimensional da luz nas artes visuais, até chegarmos ao advento da Art. Fazemos uma análise da construção do espaço pela luz nas obras de Dan Flavin. Discutimos então o conceito de coisa a partir de Hannah Arendt, Martin Heidegger e Bill Brown, e o conceito Formatividade a partir de Luigi Pareyson. No último capítulo, fazemos uma análise de um processo poético do autor desta pesquisa. Após as considerações finais, o trabalho traz ainda um apêndice sobre os tipos de fonte luminosa mais utilizados na construção em Light ArtAbstract: This research has as its theme light as material to artistic making, and its objective is to analyze and understand how luminous objects are transformed into artworks. Therefore, we make a brief explanation about how we can understand what light is, from the perspective of philosophy and the sciences. Then we present the History of three-dimensional use of light in the visual arts, to the advent of Light Art. We do an analysis of the construction of space by light in the works of Dan Flavin. We then discuss the concept of thing from Hannah Arendt, Martin Heidegger and Bill Brown, and the sense of Formativity from Luigi Pareyson. In the last chapter, we do an analysis of a poetic process by the author of this research. After the final considerations, this work also includes an appendix on the types of light source most used in Light Art constructionMestradoArtes VisuaisMestre em Artes Visuai
    corecore