1,005 research outputs found
A comparative study of aging of the elastic fiber system of the diaphragm and the rectus abdominis muscles in rats
MOHID platform automatic calibration employing a stochastic optimization method and real data from an extreme climate event in Nova Friburgo‐RJ: Part1–digital terrain model preparation and processing of rainfall and level experimental data
Este é o primeiro de 2 artigos complementares que versam sobre a implementação de uma rotina de calibração automática acoplada a um modelo de simulação do escoamento superficial e comportamento hidráulico da rede de drenagem de uma bacia hidrográfica durante eventos de cheias, construído no sistema de modelagem de águas MOdelo HIDrodinâmico (MOHID). Como estudos de caso foram analisadas 2 bacias hidrográficas localizadas na cidade de Nova Friburgo, estado do Rio de Janeiro: bacia do rio Cônego e bacia do rio Santo Antônio. Neste primeiro artigo é apresentada a metodologia de construção do modelo dgital do terreno (MDT) e rede de drenagem das bacias de interesse na plataforma MOHID, interface MOHID GIS, bem como o processo de aquisição de dados reais de precipitação e níveis de água através do site do Instituto Estadual do Ambiente (INEA), informações imprescindíveis para a simulação de ondas de cheias na região de interesse. Os resultados foram comparados com o software ArcMap e apresentaram uma boa concordância no que tange à delimitação das bacias hidrográficas e rede de drenagem.This is the first of two complementary articles that deal with the implementation of an automatic calibration routine coupled to a simulation model of runoff and the flow of two urban watersheds, both located in the city of Nova Friburgo, State of Rio de Janeiro, Brazil. The models were built in the MOHID Waters Modelling System. This first part presents the methodology of the construction of the Digital Terrain Model–DTM and the drainage network of the studied watersheds, made in the MOHID platform, as well as the acquisition of actual rainfall data and water levels through the site of the Instituto Estadual do Ambiente–INEA. The results were compared with ArcMap software and showed a good agreement regarding the delimitation of watersheds and the drainage network.Peer Reviewe
Effects of acid-base imbalance on vascular reactivity
Acid-base homeostasis maintains systemic arterial pH within a narrow range. Whereas the normal range of pH for clinical laboratories is 7.35-7.45, in vivo pH is maintained within a much narrower range. In clinical and experimental settings, blood pH can vary in response to respiratory or renal impairment. This altered pH promotes changes in vascular smooth muscle tone with impact on circulation and blood pressure control. Changes in pH can be divided into those occurring in the extracellular space (pHo) and those occurring within the intracellular space (pHi), although, extracellular and intracellular compartments influence each other. Consistent with the multiple events involved in the changes in tone produced by altered pHo, including type of vascular bed, several factors and mechanisms, in addition to hydrogen ion concentration, have been suggested to be involved. The scientific literature has many reports concerning acid-base balance and endothelium function, but these concepts are not clear about acid-base disorders and their relations with the three known mechanisms of endothelium-dependent vascular reactivity: nitric oxide (NO/cGMP-dependent), prostacyclin (PGI2/cAMP-dependent) and hyperpolarization. During the last decades, many studies have been published and have given rise to confronting data on acid-base disorder and endothelial function. Therefore, the main proposal of this review is to provide a critical analysis of the state of art and incentivate researchers to develop more studies about these issues.FAPESPFAEP
CARACTERIZAÇÃO GEOMORFOLÓGICA DA BACIA DO RIO BACANGA, ILHA DO MARANHAO
A pesquisa tem como objetivo caracterizar a geomorfologia da bacia do rio Bacanga localizada na porção Centro-NW da Ilha do Maranhão, na qual foram desenvolvidos poucos estudos sobre essa temática, principalmente no que se refere às formas do terreno e da intensidade dos agentes morfogenéticos. Os procedimentos metodológicos adotados constam de levantamentos bibliográfico e cartográfico, e atividades de campo
Motivic Serre invariants, ramification, and the analytic Milnor fiber
We show how formal and rigid geometry can be used in the theory of complex
singularities, and in particular in the study of the Milnor fibration and the
motivic zeta function. We introduce the so-called analytic Milnor fiber
associated to the germ of a morphism f from a smooth complex algebraic variety
X to the affine line. This analytic Milnor fiber is a smooth rigid variety over
the field of Laurent series C((t)). Its etale cohomology coincides with the
singular cohomology of the classical topological Milnor fiber of f; the
monodromy transformation is given by the Galois action. Moreover, the points on
the analytic Milnor fiber are closely related to the motivic zeta function of
f, and the arc space of X.
We show how the motivic zeta function can be recovered as some kind of Weil
zeta function of the formal completion of X along the special fiber of f, and
we establish a corresponding Grothendieck trace formula, which relates, in
particular, the rational points on the analytic Milnor fiber over finite
extensions of C((t)), to the Galois action on its etale cohomology.
The general observation is that the arithmetic properties of the analytic
Milnor fiber reflect the structure of the singularity of the germ f.Comment: Some minor errors corrected. The original publication is available at
http://www.springerlink.co
Parasite Glycobiology:A Bittersweet Symphony
Human infections caused by parasitic protozoans and helminths are among the world's leading causes of death. More than a million people die each year from diseases like malaria and neglected tropical diseases like leishmaniasis, trypanosomiasis, and schistosomiasis. Patients also endure disabilities that cause lifelong suffering and that affect productivity and development [1]. More insidiously, parasites generate important economic losses, since they often also infect commercially valuable animals. Worldwide, exposure to parasites is increasing due to growing international travel and migrations, as well as climate changes, which affect the geographic distribution of the parasite vectors. The parasitic threat is also aggravated by the rise of the immunocompromised population, which is particularly sensitive to parasite infections (e.g., individuals with AIDS and other immunodeficiencies).
A common feature of protozoan parasites and helminths is the synthesis of glycoconjugates and glycan-binding proteins for protection and to interact and respond to changes in their environment. To address the many challenges associated with the study of the structure, the biosynthesis, and the biology of parasitic glycans, the authors of this article have established GlycoPar, a European Marie Curie training program steered by some of the world's academic leaders in the field of parasite glycobiology, in close association with European industrial enterprises. The main scientific goal of this network is the description of novel paradigms and models by which parasite glycoconjugates play a role in the successful colonization of the different hosts. By means of a training-through-research program, the aim of the network is to contribute to the training of a generation of young scientists capable of tackling the challenges posed by parasite glycobiology
Identification and functional characterization of a highly divergent N-acetylglucosaminyltransferase I (TbGnTI) in <em>Trypanosoma brucei</em>
Trypanosoma brucei expresses a diverse repertoire of N-glycans, ranging from oligomannose and paucimannose structures to exceptionally large complex N-glycans. Despite the presence of the latter, no obvious homologues of known β1–4-galactosyltransferase or β1–2- or β1–6-N-acetylglucosaminyltransferase genes have been found in the parasite genome. However, we previously reported a family of putative UDP-sugar-dependent glycosyltransferases with similarity to the mammalian β1–3-glycosyltransferase family. Here we characterize one of these genes, TbGT11, and show that it encodes a Golgi apparatus resident UDP-GlcNAc:α3-d-mannoside β1–2-N-acetylglucosaminyltransferase I activity (TbGnTI). The bloodstream-form TbGT11 null mutant exhibited significantly modified protein N-glycans but normal growth in vitro and infectivity to rodents. In contrast to multicellular organisms, where the GnTI reaction is essential for biosynthesis of both complex and hybrid N-glycans, T. brucei TbGT11 null mutants expressed atypical “pseudohybrid” glycans, indicating that TbGnTII activity is not dependent on prior TbGnTI action. Using a functional in vitro assay, we showed that TbGnTI transfers UDP-GlcNAc to biantennary Man(3)GlcNAc(2), but not to triantennary Man(5)GlcNAc(2), which is the preferred substrate for metazoan GnTIs. Sequence alignment reveals that the T. brucei enzyme is far removed from the metazoan GnTI family and suggests that the parasite has adapted the β3-glycosyltransferase family to catalyze β1–2 linkages
Transverse spin dynamics in a spin-polarized Fermi liquid
The linear equations for transverse spin dynamics in weakly polarised
degenerate Fermi liquid with arbitrary relationship between temperature and
polarization are derived from Landau-Silin phenomenological kinetic equation
with general form of two-particle collision integral. The temperature and
polarization dependence of the spin current relaxation time is established. It
is found in particular that at finite polarization transverse spin wave damping
has a finite value at T=0. The analogy between temperature dependences of spin
waves attenuation and ultrasound absorption in degenerate Fermi liquid at
arbitrary temperature is presented. We also discuss spin-polarized Fermi liquid
in the general context of the Fermi-liquid theory and compare it with "Fermi
liquid" with spontaneous magnetization.Comment: 10 page
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