Página 9 dos resultados de 3963 itens digitais encontrados em 0.011 segundos

DOES THE CHRONOTYPE CLASSIFICATION NEED TO BE UPDATED? PRELIMINARY FINDINGS

MARTYNHAK, Bruno Jacson; LOUZADA, Fernando Mazzilli; PEDRAZZOLI, Mario; ARAUJO, John Fontenele
Fonte: INFORMA HEALTHCARE Publicador: INFORMA HEALTHCARE
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
26.49%
Traditionally, chronotype classification is based on the Morningness-Eveningness Questionnaire (MEQ). It is implicit in the classification that intermediate individuals get intermediate scores to most of the MEQ questions. However, a small group of individuals has a different pattern of answers. In some questions, they answer as ""morning-types"" and in some others they answer as ""evening-types,"" resulting in an intermediate total score. ""Evening-type"" and ""Morning-type"" answers were set as A(1) and A(4), respectively. Intermediate answers were set as A(2) and A(3). The following algorithm was applied: Bimodality Index = (Sigma A(1) x Sigma A(4))(2) - (Sigma A(2) x Sigma A(3))(2). Neither-types that had positive bimodality scores were classified as bimodal. If our hypothesis is validated by objective data, an update of chronotype classification will be required. (Author correspondence: brunojm@ymail.com)

Sr and Nd isotopic geochemistry of the early ultramafic-mafic rocks of the Mako bimodal volcanic belt of the Kedougou-Kenieba inlier (Senegal)

NGOM, Papa Malick; Cordani, Umberto Giuseppe; Teixeira, Wilson; Janasi, Valdecir de Assis
Fonte: SPRINGER HEIDELBERG Publicador: SPRINGER HEIDELBERG
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
26.49%
The Mako bimodal volcanic belt of the Kedougou-Kenieba inlier is composed of volcanic basalts and peridotites interbedded by quartzites and limestones intruded by different generations of granitoids. The early volcanic episode of the belt is constituted of submarine basalts with peridotite similar to those of the oceanic abyssal plains. It is intruded by the Badon Kakadian TTG-granitic batholite dated around 2200 Ma. The second volcanic phase is constituted of basaltic, andesitic, and felsitic flows exhibit structures of aerial volcanic rocks. It is intruded by granites dated between 2160 and 2070 Ma. The general pattern of trace element variation of submarine volcanic rocks is consistent with those of basalts from oceanic plateaus which are the modern equivalent of the Archean greenstones belts. The Nd and Sr isotopic systematics typical of juvenile material indicates that the source of these igneous rocks is derived from a depleted mantle source. These results are consistent with the idea of a major accretion within the West African Craton occurring at about 2.1 Ga and corresponding to an important process of mantle-oceanic lithosphere differentiation.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); FAPESP

Bimodal extension based on the skew-normal distribution with application to pollen data

GOMEZ, Hector W.; ELAL-OLIVERO, David; SALINAS, Hugo S.; BOLFARINE, Heleno
Fonte: JOHN WILEY & SONS LTD Publicador: JOHN WILEY & SONS LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
26.49%
This paper considers an extension to the skew-normal model through the inclusion of an additional parameter which can lead to both uni- and bi-modal distributions. The paper presents various basic properties of this family of distributions and provides a stochastic representation which is useful for obtaining theoretical properties and to simulate from the distribution. Moreover, the singularity of the Fisher information matrix is investigated and maximum likelihood estimation for a random sample with no covariates is considered. The main motivation is thus to avoid using mixtures in fitting bimodal data as these are well known to be complicated to deal with, particularly because of identifiability problems. Data-based illustrations show that such model can be useful. Copyright (C) 2009 John Wiley & Sons, Ltd.; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); CNPq-Brasil; [FONDECYT 1060727]; [7070074]; [DIUDA-221180]; [DIUDA-221153]

The log-bimodal-skew-normal model. A geochemical application

BOLFARINE, Heleno; GOMEZ, Hector W.; RIVAS, Luisa I.
Fonte: WILEY-BLACKWELL Publicador: WILEY-BLACKWELL
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
26.49%
The main objective of this paper is to study a logarithm extension of the bimodal skew normal model introduced by Elal-Olivero et al. [1]. The model can then be seen as an alternative to the log-normal model typically used for fitting positive data. We study some basic properties such as the distribution function and moments, and discuss maximum likelihood for parameter estimation. We report results of an application to a real data set related to nickel concentration in soil samples. Model fitting comparison with several alternative models indicates that the model proposed presents the best fit and so it can be quite useful in real applications for chemical data on substance concentration. Copyright (C) 2011 John Wiley & Sons, Ltd.; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); CNPq (Brazil); FONDECYT (Chile)[1090411]; FONDECYT (Chile)

Magnetophotoluminescence study of GaAs/AlGaAs coupled double quantum wells with bimodal heterointerface roughness

Lopes, E. M.; Duarte, J. L.; Dias, I. F. L.; Laureto, E.; Guimaraes, P. S. S.; Subtil, A. G. S.; Quivy, Alain Andre
Fonte: ELSEVIER SCIENCE BV; AMSTERDAM Publicador: ELSEVIER SCIENCE BV; AMSTERDAM
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
26.49%
This work reports on the results of magnetophotoluminescence (MPL) measurements carried out in a sample containing two Al0.35Ga0.65As/GaAs, coupled double quantum wells (CDQWs), with inter-well barriers of different thicknesses, which have the heterointerfaces characterized by a distribution of bimodal roughness. The MPL measurements were performed at 4 K, with magnetic fields applied parallel to the growth direction, and varying from 0 to 12 T. The diamagnetic shift of the photoluminescence (PL) peaks is more sensitive to changes in the confinement potential, due to monolayer variations in the mini-well thickness, rather than to the exciton localization at the local potential fluctuations. As the magnetic field increases, the relative intensities of the two peaks in each PL band inverts, what is attributed to the reduction in the radiative lifetime of the delocalized excitons, which results in the radiative recombination, before the excitonic migration between the higher and lower energy regions in each CDQW occurs. The dependence of the full width at half maximum (FWHM) on magnetic field shows different behaviors for each PL peak, which are attributed to the different levels and correlation lengths of the potential fluctuations present in the regions associated with each recombination channel. (C) 2011 Elsevier B.V. All rights reserved.; Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP); Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP); Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES); Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES); Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq); Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq); Fundacao Araucaria de Apoio ao Desenvolvimento Cientifico e Tecnologico do Parana; Fundacao Araucaria de Apoio ao Desenvolvimento Cientifico e Tecnologico do Parana (Fundacao Araucaria); Fundacao Banco do Brasil (FBB); Fundacao Banco do Brasil (FBB)

The Role of Immunity and Seasonality in Cholera Epidemics

Sanches, Rosangela P.; Ferreira, Claudia P.; Kraenkel, Roberto André
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica Formato: 2916-2931
ENG
Relevância na Pesquisa
26.49%
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); This paper presents a mathematical model for cholera epidemics which comprises seasonality, loss of host immunity, and control mechanisms acting to reduce cholera transmission. A collection of data related to cholera disease allows us to show that outbreaks in endemic areas are subject to a resonant behavior, since the intrinsic oscillation period of the disease (similar to 1 year) is synchronized with the annual contact rate variation. Moreover, we argue that the short period of the host immunity may be associated to secondary peaks of incidence observed in some regions (a bimodal pattern). Finally, we explore some possible mechanisms of cholera control, and analyze their efficiency. We conclude that, besides mass vaccination-which may be impracticable-improvements in sanitation system and food/personal hygiene are the most effective ways to prevent an epidemic.

Magnetophotoluminescence study of GaAs/AlGaAs coupled double quantum wells with bimodal heterointerface roughness

Lopes, E. M.; Duarte, J. L.; Dias, I. F. L.; Laureto, E.; Guimaraes, P. S. S.; Subtil, A. G. S.; Quivy, A. A.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 1183-1187
ENG
Relevância na Pesquisa
26.49%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); This work reports on the results of magnetophotoluminescence (MPL) measurements carried out in a sample containing two Al0.35Ga0.65As/GaAs, coupled double quantum wells (CDQWs), with inter-well barriers of different thicknesses, which have the heterointerfaces characterized by a distribution of bimodal roughness. The MPL measurements were performed at 4 K, with magnetic fields applied parallel to the growth direction, and varying from 0 to 12 T. The diamagnetic shift of the photoluminescence (PL) peaks is more sensitive to changes in the confinement potential, due to monolayer variations in the mini-well thickness, rather than to the exciton localization at the local potential fluctuations. As the magnetic field increases, the relative intensities of the two peaks in each PL band inverts, what is attributed to the reduction in the radiative lifetime of the delocalized excitons, which results in the radiative recombination, before the excitonic migration between the higher and lower energy regions in each CDQW occurs. The dependence of the full width at half maximum (FWHM) on magnetic field shows different behaviors for each PL peak...

A new firefly luciferase with bimodal spectrum: Identification of structural determinants of spectral pH-sensitivity in firefly luciferases

Viviani, Vadim R.; Oehlmeyer, T. L.; Arnoldi, F. G C; Brochetto-Braga, M. R.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 843-848
ENG
Relevância na Pesquisa
26.49%
Fireflies emit flashes in the green-yellow region of the spectrum for the purpose of sexual attraction. The bioluminescence color is determined by the luciferases. It is well known that the in vitro bioluminescence color of firefly luciferases can be shifted toward the red by lower pH and higher temperature; for this reason they are classified as pH-sensitive luciferases. However, the mechanism and structural origin of pH sensitivity in fireflies remains unknown. Here we report the cloning of a new luciferase from the Brazilian twilight active firefly Macrolampis sp2, which displays an unusual bimodal spectrum. The recombinant luciferase displays a sensitive spectrum with the peak at 569 nm and a shoulder in the red region. Comparison of the bioluminescence spectra of Macrolampis, Photinus and Cratomorphus firefly luciferases shows that the distinct colors are determined by the ratio between green and red emitters under luciferase influence. Comparison of Macrolampis luciferase with the highly similar North American Photinus pyralis luciferase (91%) showed few substitutions potentially involved with the higher spectral sensitivity in Macrolampis luciferase. Site-directed mutagenesis showed that the natural substitution E354N determines the appearance of the shoulder in the red region of Macrolampis luciferase bioluminescence spectrum...

Liquid foam templates associated with the sol-gel process for production of zirconia ceramic foams

Beozzo, Cristiane Carolina; Alves-Rosa, Marinalva Aparecida; Pulcinelli, Sandra Helena; Santilli, Celso Valentim
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 1967-1979
ENG
Relevância na Pesquisa
26.49%
The unique properties of ceramic foams enable their use in a variety of applications. This work investigated the effects of different parameters on the production of zirconia ceramic foam using the sol-gel process associated with liquid foam templates. Evaluation was made of the influence of the thermal treatment temperature on the porous and crystalline characteristics of foams manufactured using different amounts of sodium dodecylsulfate (SDS) surfactant. A maximum pore volume, with high porosity (94%) and a bimodal pore size distribution, was observed for the ceramic foam produced with 10% SDS. Macropores, with an average size of around 30 μm, were obtained irrespective of the SDS amount, while the average size of the supermesopores increased systematically as the SDS amount was increased up to 10%, after which it decreased. X-ray diffraction analyses showed that the sample treated at 500 °C was amorphous, while crystallization into a tetragonal metastable phase occurred at 600 °C due to the presence of sulfate groups in the zirconia structure. At 800 and 1000 °C the monoclinic phase was observed, which is thermodynamically stable at these temperatures. © 2013 by the authors; licensee MDPI, Basel, Switzerland.

Evidence of a bimodal effect on Saccharomyces cerevisiae UE-ME3 by vanadium (V) stress - a dual response to different V2O5 medium concentration detected in the rate growth, GSH/GSSG, G6PD, CAT T and GR enzymatic activities

Alves-Pereira, I; Rosado, T; Ferreira, R
Fonte: World scientific publishing Co Publicador: World scientific publishing Co
Tipo: Parte de Livro
ENG
Relevância na Pesquisa
26.49%
The aim of this work was to evaluate the effects of five V2O5 medium concentrations ranging from 0.5 to 2.0 mM on cell viability, redox status and antioxidants enzymes of wine yeast S. cerevisiae UE-ME3. A slightly decrease of yeast cells growth rate for 0.5 and 1.0 mM, and a significantly decrease for 1.5 and 2.0 mM were observed. Conversely, a significantly increase of G6PD activity and GSH/GSSG ratio for 0.5 mM V2O5, and a significantly decrease of GR and CAT T activities for 0.5 and 1.0 mM also occurs. Furthermore, for V2O5, ranging between 1.0 and 2.0 mM, we observed a significantly decrease of G6PD and GSH/GSSG ratio, occurring, at the same conditions a reverse effect on GR and CAT T activities, with a significant increase of GR for 1.5 and 2.0 mM. We suppose that bimodal response of S. cerevisiae to vanadium pentoxide, eventually mediated by NADPH and GSH level, rule cell death.

Late sodic metasomatism evidences in bimodal volcanic rocks of the Acampamento Velho Alloformation, Neoproterozoic III, southern Brazil

Almeida,Delia Del Pilar M. de; Pereira,Vitor P.; Machado,Adriane; Zerfass,Henrique; Freitas,Ricardo
Fonte: Academia Brasileira de Ciências Publicador: Academia Brasileira de Ciências
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2007 EN
Relevância na Pesquisa
26.49%
A mineralogical study was carried out in mafic and felsic volcanic rocks of the Acampamento Velho Alloformation at Cerro do Bugio, Perau and Serra de Santa Bárbara areas (Camaquã Basin) in southern Brazil. The Acampamento Velho bimodal event consists of two associations: lower mafic at the base and upper felsic at the top. Plagioclase and alkali-feldspar were studied using an electronic microprobe, and magnetite, ilmenite, rutile, illite and alkali-feldspar were investigated through scanning electron microscopy. The rocks were affected by a process of late sodic autometasomatism. In mafic rocks, Ca-plagioclase was transformed to albite and pyroxenes were altered. In felsic rocks, sanidine was partially pseudomorphosed, generating heterogeneous alkali-feldspar. In this association, unstable Ti-rich magnetite was replaced by rutile and ilmenite. In mafic rocks, the crystallization sequence was: (1) Ti-rich magnetite (?), (2) pyroxene and Ca-plagioclase, (3) albite (alteration to Ca-plagioclase), (4) sericite, chlorite and calcite (alteration to pyroxene), and kaolinite (alteration to plagioclase/albite). In felsic rocks: (1) zircon, (2) Ti-rich magnetite, (3) sanidine, (4) quartz. The introduction of late Na-rich fluids, generated the formation of (5) heterogeneous alkali-feldspar...

Sobreposição no desenvolvimento bilíngue bimodal

Quadros,Ronice Müller de; Lillo-Martin,Diane; Pichler,Deborah Chen
Fonte: Faculdade de Letras - Universidade Federal de Minas Gerais Publicador: Faculdade de Letras - Universidade Federal de Minas Gerais
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2014 PT
Relevância na Pesquisa
26.49%
Crianças bilíngues desenvolvem sensibilidade para escolher as línguas de seus interlocutores de forma muito precoce, o que se reflete nas proporções diferenciadas do uso de cada língua. Os fatores tais como o contexto do discurso e a relativa dominância das línguas na comunidade podem também determinar o grau de diferenciação dos usos das línguas nas crianças em fase préescolar. Crianças bilíngues bimodais, ou seja, as que estão adquirindo uma língua de sinais e uma língua falada, simultaneamente, estão diante de um contexto mais complexo de negociações. Além da alternância de línguas, essas crianças produzem a sobreposição de línguas, que é um fenômeno sociolinguístico análogo àquele, mas sem a supressão de uma das línguas. Este estudo analisa produções espontâneas de crianças bilíngues bimodais, interagindo com seus interlocutores surdos ou ouvintes (duas crianças americanas e duas brasileiras). Nossos resultados mostram que, mesmo nas produções mais iniciais, as crianças produzem mais enunciados sinalizados com seus interlocutores surdos e mais enunciados falados com os seus interlocutores ouvintes. Todas as quatro crianças produziram enunciados bimodais, tanto nas sessões em que a língua alvo era a fala ou os sinais...

Bimodal regulation of Na+–Ca2+ exchanger by β-adrenergic signaling pathway in shark ventricular myocytes

Woo, Sun-Hee; Morad, Martin
Fonte: The National Academy of Sciences Publicador: The National Academy of Sciences
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
26.49%
In shark heart, the Na+–Ca2+ exchanger serves as a major pathway for both Ca2+ influx and efflux, as there is only rudimentary sarcoplasmic reticulum in these hearts. The modulation of the exchanger by a β-adrenergic agonist in whole-cell clamped ventricular myocytes was compared with that of the Na+–Ca2+ exchanger blocker KB-R7943. Application of 5 μM isoproterenol and 10 μM KB-R7943 suppressed both the inward and the outward Na+–Ca2+ exchanger current (INa−Ca). The isoproterenol effect was mimicked by 10 μM forskolin. Isoproterenol and forskolin shifted the reversal potential (Erev) of INa−Ca by approximately −23 mV and −30 mV, respectively. An equivalent suppression of outward INa−Ca by KB-R7943 to that by isoproterenol produced a significantly smaller shift in Erev of about −4 mV. The ratio of inward to outward exchanger currents was also significantly larger in isoproterenol- than in control- and KB-R7943-treated myocytes. Our data suggest that the larger ratio of inward to outward exchanger currents as well as the larger shift in Erev with isoproterenol results from the enhanced efficacy of Ca2+ efflux via the exchanger. The protein kinase A-mediated bimodal regulation of the exchanger in parallel with phosphorylation of the Ca2+ channel and enhancement of its current may have evolved to satisfy the evolutionary needs for accelerated contraction and relaxation in hearts of animals with vestigial sarcoplasmic Ca2+ release stores.

Cyclic AMP Signaling Functions as a Bimodal Switch in Sympathoadrenal Cell Development in Cultured Primary Neural Crest Cells

Bilodeau, Matthew L.; Boulineau, Theresa; Hullinger, Ronald L.; Andrisani, Ourania M.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /05/2000 EN
Relevância na Pesquisa
26.49%
Cells of the vertebrate neural crest (crest cells) are an invaluable model system to address cell fate specification. Crest cells are amenable to tissue culture, and they differentiate to a variety of neuronal and nonneuronal cell types. Earlier studies have determined that bone morphogenetic proteins (BMP-2, -4, and -7) and agents that elevate intracellular cyclic AMP (cAMP) stimulate the development of the sympathoadrenal (SA, adrenergic) lineage in neural crest cultures. To investigate whether interactive mechanisms between signaling pathways influence crest cell differentiation, we characterized the combinatorial effects of BMP-2 and cAMP-elevating agents on the development of quail trunk neural crest cells in primary culture. We report that the cAMP signaling pathway modulates both positive and negative signals influencing the development of SA cells. Specifically, we show that moderate activation of cAMP signaling promotes, in synergy with BMP-2, SA cell development and the expression of the SA lineage-determining gene Phox2a. By contrast, robust activation of cAMP signaling opposes, even in the presence of BMP-2, SA cell development and the expression of the SA lineage-determining ASH-1 and Phox2 genes. We conclude that cAMP signaling acts as a bimodal regulator of SA cell development in neural crest cultures.

Bimodal activation of SMC ATPase by intra- and inter-molecular interactions

Hirano, Michiko; Anderson, David E.; Erickson, Harold P.; Hirano, Tatsuya
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
Publicado em 15/06/2001 EN
Relevância na Pesquisa
26.49%
Structural maintenance of chromosomes (SMC) proteins play fundamental roles in higher-order chromosome dynamics from bacteria to humans. It has been proposed that the Bacillus subtilis SMC (BsSMC) homodimer is composed of two anti-parallel coiled-coil arms, each having an ATP-binding domain at its distal end. It remains totally unknown, however, how the two-armed structure supports ATP-dependent actions of BsSMC. By constructing a number of mutant derivatives including ‘single-armed’ BsSMC, we show here that the central hinge domain provides a structural flexibility that allows opening and closing of the two arms. This unique structure brings about bimodal regulation of the SMC ATPase cycle. Closing the arm can trigger ATP hydrolysis by allowing an end–end interaction within a dimer (intramolecular mode). When bound to DNA, ATP promotes a dimer–dimer interaction, which in turn activates their DNA-dependent ATPase activity (intermolecular mode). Our results reveal a novel mechanism of ATPase regulation and provide mechanistic insights into how eukaryotic SMC protein complexes could mediate diverse chromosomal functions, such as chromosome condensation and sister chromatid cohesion.

Two novel thioesterases are key determinants of the bimodal distribution of acyl chain length of Cuphea palustris seed oil.

Dehesh, K; Edwards, P; Hayes, T; Cranmer, A M; Fillatti, J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1996 EN
Relevância na Pesquisa
26.49%
The seed oil of Cuphea palustris has an unusual fatty-acyl composition, whereby the principal fatty-acyl groups, myristate (64%) and caprylate (20%), differ by more than two methylenes. We have isolated two thioesterase (TE) cDNAs from C. palustris, encoding proteins designated Cp FatB1 and Cp FatB2, which, when expressed in Escherichia coli, have TE activities specific for 8:0/10:0- and 14:0/16:0-acyl carrier protein substrates, respectively. The specific activities of the recombinant affinity-purified enzymes indicate that Cp FatB2 is kinetically superior to Cp FatB1. This result is consistent with the predominance of 14:0 in the seed oil, despite apparently equal mRNA abundance of the two transcripts in the seed. In C. palustris the expression of both sequences is confined to the seed tissues. Based on these findings we propose that these two enzymes are major factors determining the bimodal chain-length composition of C. palustris oil. Analysis of the immature and mature seed oil by reverse-phase high-performance liquid chromatography confirmed that the principal triglycerides contain both 8:0 and 14:0. This result indicates that both fatty acids are synthesized at the same time and in the same cells at all developmental stages during oil deposition...

Bimodal interaction between replication-protein A and Dna2 is critical for Dna2 function both in vivo and in vitro

Bae, Kwang-Hee; Kim, Hee-Sook; Bae, Sung-Ho; Kang, Ho-Young; Brill, Steven; Seo, Yeon-Soo
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
Publicado em 15/06/2003 EN
Relevância na Pesquisa
26.49%
We have previously shown that replication- protein A (RPA), the heterotrimeric single-stranded DNA binding protein of eukaryotes, plays a role in Okazaki fragment processing by acting as a molecular switch between the two endonucleases, Dna2 and Fen1, to ensure the complete removal of primer RNAs in Saccharomyces cerevisiae. The stimulation of Dna2 endonuclease activity by RPA requires direct protein–protein interaction. In this report we have analyzed genetically and biochemically the interaction of Dna2 with RPA. RFA1, the gene encoding the large subunit of RPA, displayed allele-specific interactions with DNA2 that included synthetic lethality and intergenic complementation. In addition, we identified physical and functional interactions between these proteins and found that RPA binds Dna2 predominantly through its large subunit, Rpa1. Consistent with the mapping of synthetic lethal mutations, robust interaction localizes to the C-termini of these proteins. Moreover, the N-terminal domains of Dna2 and Rpa1 appear to be important for a functional interaction because the N-terminal domain of RPA1 was required to maximally stimulate Dna2 endonuclease activity. We propose that a bimodal interaction of Dna2 with Rpa1 is important for Dna2 function both in vivo and in vitro. The relevance of each interaction with respect to the function of the Dna2 endonuclease activity is discussed.

Bimodal waveguide interferometer device based on silicon photonics technology for label-free and high sensitive biosensing

González Guerrero, Ana Belén
Fonte: [Barcelona] : Universitat Autònoma de Barcelona, Publicador: [Barcelona] : Universitat Autònoma de Barcelona,
Tipo: Tesis i dissertacions electròniques; info:eu-repo/semantics/doctoralThesis Formato: application/pdf
Publicado em //2013 ENG; ENG
Relevância na Pesquisa
26.71%
Els dispositius òptics biosensors basats en la detecció d'ona evanescent podrien superar les limitacions dels tests de diagnòstic actuals (que són lents i cars) degut a la possibilitat de realitzar les deteccions a temps reals i fent servir un esquema sense la necessitat de marcatges. Entre els diferents transductors òptics, els interferomètrics són els que posseeixen els millors límits de detecció (LOD) deguts a canvis en el índex de refracció de dissolucions (10-7-10-8 Unitats d'Índex de Refracció, RIU) així com per sensibilitat superficial (en el rang dels pg/ml) i un rang lineal més gran. No obstant, les configuracions interferomètriques (l'interferòmetre Mach-Zehnder o el Young) més usuals fan servir un divisor amb forma de Y, que és essencial per dividir o recombinar la llum, lo qual, degut a les toleràncies de les actuals tècniques de fabricació es una gran desavantatge per la reproduibilitat d'aquests dispositius. Per evitar aquests problemes, hem desenvolupat una configuració interferomètrica més simple basada en un guia de ones recte on dos modes de llum de la mateixa polarització interfereixen entre si. Aquesta configuració elimina la complexitat dels interferòmetres més utilitzats i conseqüentment...

Currículum Bimodal : reduirem el fracàs escolar?

Marquès, Pere
Fonte: Universidade Autônoma de Barcelona Publicador: Universidade Autônoma de Barcelona
Tipo: Artigo de Revista Científica Formato: application/pdf
Publicado em //2012 CAT
Relevância na Pesquisa
26.71%
Una investigació desenvolupada al Departament de Pedagogia Aplicada de la UAB ha estudiat l'aplicació del currículum bimodal, que separa els coneixements que s'han de memoritzar de les competències que s'han d'adquirir, en diversos centres d'ensenyament a Espanya i a Amèrica Llatina. Els resultats mostren una millora en el rendiment dels alumnes, alhora que també un increment en la seva motivació davant de les classes. Així, el currículum bimodal obre una porta a l'esperança en la millora de l'educació i en la reducció del fracàs escolar.

Bimodal Distribution of Sulfuric Acid Aerosols in the Upper Haze of Venus

Gao, Peter; Zhang, Xi; Crisp, David; Bardeen, Charles G.; Yung, Yuk L.
Fonte: Elsevier Publicador: Elsevier
Tipo: Article; PeerReviewed Formato: application/pdf
Publicado em 01/03/2014
Relevância na Pesquisa
26.71%
Observations by the SPICAV/SOIR instruments aboard Venus Express have revealed that the upper haze (UH) of Venus, between 70 and 90 km, is variable on the order of days and that it is populated by two particle modes. We use a one-dimensional microphysics and vertical transport model based on the Community Aerosol and Radiation Model for Atmospheres to evaluate whether interaction of upwelled cloud particles and sulfuric acid particles nucleated in situ on meteoric dust are able to generate the two observed modes, and whether their observed variability are due in part to the action of vertical transient winds at the cloud tops. Nucleation of photochemically produced sulfuric acid onto polysulfur condensation nuclei generates mode 1 cloud droplets, which then diffuse upwards into the UH. Droplets generated in the UH from nucleation of sulfuric acid onto meteoric dust coagulate with the upwelled cloud particles and therefore cannot reproduce the observed bimodal size distribution. By comparison, the mass transport enabled by transient winds at the cloud tops, possibly caused by sustained subsolar cloud top convection, are able to generate a bimodal size distribution in a time scale consistent with Venus Express observations. Below the altitude where the cloud particles are generated...