544 research outputs found
Disk and elliptical galaxies within renormalization group improved gravity
The paper is about possible effects of infrared quantum contributions to
General Relativity on disk and elliptical galaxies. The Renormalization Group
corrected General Relativity (RGGR model) is used to parametrize these quantum
effects. The new RGGR results presented here concern the elliptical galaxy NGC
4374 and the dwarf disk galaxy DDO 47. Using the effective approach to Quantum
Field Theory in curved background, one can argue that the proper RG energy
scale, in the weak field limit, should be related to the Newtonian potential.
In the context of galaxies, this led to a remarkably small variation of the
gravitational coupling G, while also capable of generating galaxy rotation and
dispersion curves of similar quality to the the best dark matter profiles
(i.e., the profiles that have a core).Comment: 5 pages. This paper is based on a talk given by D.C. Rodrigues at the
I CosmoSul meeting (Rio de Janeiro, RJ - Brazil. August, 01-05, 2011). To be
published in AIP conference Proceeding
O ensino de Zoologia evolutiva na educação básica : uma experiência desenvolvida nos primeiros anos do ensino fundamental
A Zoologia ensinada desde as séries iniciais distancia-se das atuais propostas para um ensino evolutivo. As visões utilitaristas e antropocêntricas sobre os animais são prevalentes e dificultam a formação de conceitos e a aprendizagem sobre Evolução em séries escolares posteriores. Com basesnesses pressupostos foi desenvolvida uma pesquisa de intervenção com 16 alunos de 3º ano do Ensino Fundamental, objetivando-se identificar, descrever e analisar os aspectos potenciais e limitantes de um processo educativo de Zoologia Evolutiva nas séries iniciais da escola básica, utilizando-se fundamentos teórico-práticos de Ausubel e Vigotski. As conclusões dessa experiência orientam-se para uma real e consistente possibilidade de aprendizagem significativa de Zoologia Evolutiva nas séries iniciais
Characterization of Acrocarpus fraxinifolius wood submitted to heat treatment
Aiming to provide greater visibility for the wood species Acrocarpus fraxinifolius, the present study sought to analyze the influence of heat treatment on an industrial scale applied to wood species, also popularly known as Indian cedar. The heat treatment was carried out in an autoclave, with temperature and pressure control, and with saturated steam injection, for temperatures 155 ºC, 165 ºC, 175 ºC, and 185 ºC. Physical, chemical, and mechanical tests were carried out for the analyzed wood. The content of holocellulose and total lignin decreased, while the content of extractives showed a substantial increase. The density increased after the heat treatment, however the treated wood showed cracks, and these cracks influenced the significant loss of the values of the mechanical properties of compression, tension, and flexion. The shear showed strength gain for the temperature of 155 ºC, and the wood treated at 165 ºC was equivalent to untreated wood. The woods submitted to temperatures of 175 ºC and 185 ºC presented strength losses. The heat treatment in question contributes to increase the visibility, use and market value of wood
Why not "do simple things in a simple way": Use of the Pap test as the first step in screening genetic stability for human cultured stem cell therapy?
The aim of this study was to analyze adipose tissue-derived mesenchymal stem cells (AT-MSCs) using the Pap test as a first screening step to evaluate genetic stability. Human adipose tissue from six healthy female donors was obtained from elective liposuction procedures. The cells were isolated, cultivated at P2/P3, characterized by flow cytometric analysis, and differentiation induced. The AT-MSCs were stained by Papanicolaou staining and analyzed according to the Bethesda classification, and viability-apoptosis relationships were evaluated. The results of the Pap test for Sample I indicated high-grade alterations consistent with genetic instability; for Samples II-V, atypical cells of undetermined significance; and for Sample VI, normal cells. These results demonstrate the potential of using the Pap test as an initial screening step to evaluate the genetic stability of cultured AT-MSCs and also suggest its use for other adherent cells such as embryonic stem cells or induced pluripotent stem cells
Biological activity of the aqueous extract of Lychnophora pinaster Mart
Lyophilized aqueous extract (LAE) from Lychnophora pinaster Mart (Asteraceae) aerial parts was evaluated in the search of possible biological activities. LAE exhibited trypanocidal activity (113.62 μg/mL), but could not inhibit 5-lipoxygenase in vitro (17% of inhibition). LAE chemical characterization by HPLC with UV-Diode Array Detector showed the presence of caffeic acid, isochlorogenic acid, vitexin, isovitexin and quercetin, in comparison with authentic samples
Traducción, adaptación cultural y validación de la escala Venous International Assessment al portugués europeo
Background: A significant number of adult patients experience difficult peripheral intravenous ac-cess, leading to multiple puncture attempts and venous network depletion. The Venous International Assessment (VIA) Scale is referenced internationally as a reliable instrument that classifies patients’ peripheral intravenous accesses and determines the risk of related complications. Objectives: To translate, culturally adapt and validate the VIA Scale to European Portuguese. Methodology: Study of the translation, cultural adaptation, and evaluation of the psychometric prop-erties of the VIA Scale in a nonprobability sample with 100 patients in need of peripheral intravenous catheterization. Results: The Portuguese version of the VIA Scale (EARV) revealed moderate inter-rater reliability scores (k = 0.490; p < 0.0005). The criterion and construct validity of the EARV were assessed through predictive, convergent, and correlational analysis, with moderate to large magnitudes, and statistical significance. Conclusion: The EARV is a reliable and valid instrument that can assist Portuguese health professionals in determining and categorizing difficult peripheral intravenous access. Further studies are recommended to test the transversal applicability of the scale.Enquadramento: Um número significativo de pessoas adultas tem um acesso venoso periférico difícil, o que leva a múltiplas tentativas de punção e ao esgotamento da rede venosa. A escala Venous International Assessment (VIA) é considerada a nível internacional como um instrumento fiável que classifica as vias de acesso venoso periférico das pessoas e determina o risco de complicações associadas. Objetivos: Traduzir, adaptar culturalmente e validar a Escala VIA para português europeu. Metodologia: Estudo da tradução, adaptação cultural, e avaliação das propriedades psicométricas da escala VIA em amostra não probabilística de 100 pessoas doentes a precisar de cateterização venosa periférica. Resultados: A versão em português europeu da escala VIA (EARV) revelou valores moderados de fiabilidade inter-observadores (k = 0,490; p < 0,0005). As validades do critério e do constructo da EARV foram avaliadas através de análise preditiva, convergente e correlacional, com magnitudes moderadas a grandes e significância estatística. Conclusão: A EARV é um instrumento fiável e válido que pode ajudar os profissionais de saúde portugueses na determinação e categorização de acessos venosos periféricos difíceis. Contudo, recomenda-se a realização de mais estudos para testar a aplicabilidade transversal desta escala.Marco contextual: Un número significativo de adultos experimenta dificultades al ser sometido a un acceso venoso periférico, lo que provoca múltiples intentos de punción y el deterioro de la red venosa. La escala Venous International Assessment (VIA) está considerada internacionalmente como un instrumento fiable que clasifica los accesos venosos periféricos en las personas y determina el riesgo de complicaciones relacionadas. Objetivos: Traducir, adaptar culturalmente y validar la escala VIA al portugués europeo. Metodología: Estudio de traducción, adaptación cultural y evaluación de las propiedades psicométricas de la escala VIA en una muestra no probabilística con 100 personas que necesitan ser sometidos a un cateterismo venoso periférico. Resultados: La versión portuguesa desarrollada de la escala VIA (EARV) mostró puntuaciones de concordancia entre evaluadores moderadas (k = 0,490; p < 0,0005). La validez de criterio y de constructo de la EARV se evaluó mediante un análisis predictivo, convergente y correlacional, con magnitudes de moderadas a amplias y significación estadística. Conclusión: La EARV es un instrumento fiable y válido que puede ayudar a los profesionales sanitarios portugueses a determinar y categorizar la dificultad de un acceso venoso periférico. Se necesita realizar futuros estudios para comprobar la aplicabilidad transversal de la escala.info:eu-repo/semantics/publishedVersio
Quantum corrections to gravity and their implications for cosmology and astrophysics
The quantum contributions to the gravitational action are relatively easy to
calculate in the higher derivative sector of the theory. However, the
applications to the post-inflationary cosmology and astrophysics require the
corrections to the Einstein-Hilbert action and to the cosmological constant,
and those we can not derive yet in a consistent and safe way. At the same time,
if we assume that these quantum terms are covariant and that they have relevant
magnitude, their functional form can be defined up to a single free parameter,
which can be defined on the phenomenological basis. It turns out that the
quantum correction may lead, in principle, to surprisingly strong and
interesting effects in astrophysics and cosmology.Comment: 15 pages, LaTeX, WS style, contribution to the Proceedings of the
QFEXT-2011 conference in the Centro de Ciencias de Benasque Pedro Pasqual,
Spai
Chromosome phylogeny of the subfamily Pitheciinae (Platyrrhini, Primates) by classic cytogenetics and chromosome painting
Background: The New World monkey (Platyrrhini) subfamily Pitheciinae is represented by the genera Pithecia, Chiropotes and Cacajao. In this work we studied the karyotypes of Pithecia irrorata (2n = 48) and Cacajao calvus rubicundus (2n = 45 in males and 2n = 46 in females) by G-and C-banding, NOR staining and chromosome painting using human and Saguinus oedipus whole chromosome probes. The karyotypes of both species were compared with each other and with Chiropotes utahicki (2n = 54) from the literature. Results: Our results show that members of the Pitheciinae have conserved several chromosome forms found in the inferred ancestral Platyrrhini karyotype (associations of human homologous segments 3a/21, 5/7a, 2b/16b, 8a/18, 14/15a and 10a/16a). Further, the monophyly of this subfamily is supported by three chromosomal synapomorphies (2a/10b, an acrocentric 15/14 and an acrocentric human 19 homolog). In addition, each species presents several autapomorphies. From this data set we established a chromosomal phylogeny of Pitheciinae, resulting in a single most parsimonious tree. Conclusions: In our chromosomal phylogeny, the genus Pithecia occurred in a more basal position close to the inferred ancestor of Platyrrhini, while C. c. rubicundus and C. utahicki are closely related and are linked by exclusive synapomorphies
Identification of New Genes Related to Virulence of Xanthomonas axonopodis Pv. Citri during Citrus Host Interactions
A mutant library of the bacterium Xanthomonas citri subsp. citri strain 306 pathotype A (Xac), the causative agent of most aggressive Asiatic type A citrus canker, was screened regarding altered canker symptoms after inoculations into Citrus sinensis and Citrus limonia host leaves. Twenty-six mutants have shown phenotypic virulence changes and have respectively knocked out gene identified by sequencing. In vivo growth curves were obtained for nine mutants to quantify how the mutations could affect pathogen's adaptability to growth inside and attack host plant infected tissue. Among identified genes in mutated strains, we could find those that until now had not been reported as being involved in Xac adaptation and/or virulence, such as predicted to encode for xylose repressor-like protein (XAC Delta xylR), Fe-S oxidoredutase (XAC Delta aslB), helicase IV (XAC Delta helD), ubiquinol cytochrome c oxidoreductase iron-sulfur subunit (XAC Delta petA), chromosome partitioning protein (XAC Delta parB) and cell division protein FtsB (XAC Delta ftsB), in addition to genes predicted to encode for hypothetical proteins. The new genes found in this study as being relevant to adaptation and virulence, improve the understanding of Xac fitness during citrus plant attack and canker symptoms development.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo-FAPESPCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior-CAPESCNPqFundo de Defesa da Citricultura (FUNDECITRUS)CAPESFUNDECITRUSFAPESPSao Paulo State Univ UNESP, Fac Agr Sci & Vet, Dept Technol, Jaboticabal, SP, BrazilCitriculture Res Ctr Sylvio Moreira IAC Campinas, Campinas, SP, BrazilUniv Fed Ouro Preto, Inst Exact & Biol Sci, Dept Biol Sci, Ouro Preto, MG, BrazilUniv Fed Ouro Preto, Res Ctr Biol Sci NUPEB, Inst Exact & Biol Sci, Dept Biol Sci, Ouro Preto, MG, BrazilSao Paulo State Univ UNESP, Fac Agr Sci & Vet, Plant Hlth Dept, Jaboticabal, SP, BrazilFed Univ Sao Paulo UNIFESP, Dept Biol Sci, Diadema, SP, BrazilFed Univ Sao Paulo UNIFESP, Dept Biol Sci, Diadema, SP, BrazilFAPESP: 04/02006-7Web of Scienc
Padrões de variação genética em loci sob selecção na abelha ibérica: comparação da selecção balanceada e direccional
A Península Ibérica tem sido reconhecida como um "hotspot" de diversidade c
endemismo para diversas espécies quer animais quer vegetais. Em parte esta grande
diversidade encontrada na Península Ibérica deve-se ao flicto de este local ter sido
utilizado como refúgio por diferentes espécies durante as glaciaçôes A abelha é um dos
muitos casos onde este processo aconteceu. Na verdade, a Península Ibérica é umas das
regiões da Europa onde esta espécie apresenta uma maior diversidade c complexidade
genética. A abelha ibérica que está distribuída pela Península Ibérica é o fruto de uma
hibridação natural entre a linhagem Africana c a linhagem da Europa ocidental. O
estudo de zonas híbridas tem sido muito importante para compreender os processos
evolutivos que levaram à complexidade genética tão característica dos refúgios
O objectivo deste trabalho é fazer uma abordagem inicial para perceber como é
que os diferentes tipos de selecção (balanceadora e direccional) influenciam a
diversidade genética das abelhas na Península Ibérica e tentar perceber qual o papel da
selecção na divergência adaptativa das populações. Para tal foram calculadas algumas
cstatisticas sumárias e também toram utilizados diversos sothvares que implementam
algoritmos Bayesianos de forma a verificar que estrutura é captada ao utilizar-se as
regiões do genoma sob diferentes tipos de selecção (balanceadora ou direccional). No
total foram detectados 22 loci sob selecção usando o Bayescan, 9 dos quais
apresentavam aparentam estar sob de uma selecção balanceada c 13 sob selecção
direccional. Neste trabalho é representado o padrão obtido utilizado software
"STRUCTURE
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