999 resultados para 28-265


Relevância:

20.00% 20.00%

Publicador:

Resumo:

(I)Lantadene-B: C35H52O5,M r =552.80, MonoclinicC2,a=25.65(1),b=6.819(9),c=18.75(1) Å,beta=100.61(9),V=3223(5) Å3,Z=4,D x =1.14 g cm–3 CuKagr (lambda=1.5418A),mgr=5.5 cm–1,F(000)=1208,R=0.118,wR=0.132 for 1527 observed reflections withF o ge2sgr(F o ). (II)Lantadene-C: C35H54O5·CH3OH,Mr=586.85, Monoclinic,P21,a=9.822(3),b=10.909(3),c=16.120(8)Å,beta=99.82(4),V=1702(1)Å3,Z=2,D x =1.145 g cm–3, MoKagr (lambda=0.7107Å), mgr=0.708 cm–1 F(000)=644,R=0.098, wR=0.094 for 1073 observed reflections. The rings A, B, C, D, and E aretrans, trans, trans, cis fused and are in chair, chair, sofa, half-chair, chair conformations, respectively, in both the structures. In the unit cell the molecules are stabilized by O-HctdotO hydrogen bonds in both the structures, however an additional C-HctdotO interaction is observed in the case of Lantadene-C.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A simple thermodynamic analysis of the well-known Michaelis-Menten equation (MME) of enzyme catalysis is proposed that employs the chemical potential mu to follow the Gibbs free energy changes attending the formation of the enzyme-substrate complex and its turnover to the product. The main conclusion from the above analysis is that low values of the Michaelis constant KM and high values of the turnover number k(cat) are advantageous: this supports a simple algebraic analysis of the MME, although at variance with current thinking. Available data apparently support the above findings. It is argued that transition state stabilisation - rather than substrate distortion or proximity - is the key to enzyme catalysis.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this paper, we explore a novel idea of using high dynamic range (HDR) technology for uncertainty visualization. We focus on scalar volumetric data sets where every data point is associated with scalar uncertainty. We design a transfer function that maps each data point to a color in HDR space. The luminance component of the color is exploited to capture uncertainty. We modify existing tone mapping techniques and suitably integrate them with volume ray casting to obtain a low dynamic range (LDR) image. The resulting image is displayed on a conventional 8-bits-per-channel display device. The usage of HDR mapping reveals fine details in uncertainty distribution and enables the users to interactively study the data in the context of corresponding uncertainty information. We demonstrate the utility of our method and evaluate the results using data sets from ocean modeling.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this paper, we report drain-extended MOS device design guidelines for the RF power amplifier (RF PA) applications. A complete RF PA circuit in a 28-nm CMOS technology node with the matching and biasing network is used as a test vehicle to validate the RF performance improvement by a systematic device design. A complete RF PA with 0.16-W/mm power density is reported experimentally. By simultaneous improvement of device-circuit performance, 45% improvement in the circuit RF power gain, 25% improvement in the power-added efficiency at 1-GHz frequency, and 5x improvement in the electrostatic discharge robustness are reported experimentally.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this letter, we submit our comment on the following recently published papers by Kalidas Das: (1) ``Influence of chemical reaction and viscous dissipation on MHD mixed convection flow,'' Journal of Mechanical Science and Technology 28 (5) (2014) 1881-1885; and (2) ``Cu-water nanofluid flow and heat transfer over a shrinking sheet,'' Journal of Mechanical Science and Technology 28 (12) (2014) 5089-5094. The authors attempt to present the similarity solutions in both papers. We comment that the similarity transformations considered in Refs. 1, 2] are incorrect. Thus, the results presented by Kalidas Das lead to invalid conclusions.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Contenido: Hermenéutica y estructuras históricas / Cesare Segre – Realismo y simbolismo en la geografía del Amadís de Gaula: la Insula Firme y sus dimensiones / Javier R. González – La visión insular y litoral del espacio en el Amadís de Gaula / Silvia Cristina Lastra Paz – El nivel de la historia en un relato de J. L. Borges. Un análisis narratológico / Hugo Eduardo Lombardini – Joseph de Maistre, maestro de razonamiento de Baudelaire (primera parte). La filosofía de Joseph de Maistre, entrevista en el soneto “Correspondances” de Charles Baudelaire (segunda parte) / Perla Montiveros de Mollo – Imágenes del “Hombre nuevo” en la obra de Leopoldo Marechal / Javier de Navascués – Valores cronotópicos y técnicas significantes al servicio de la “ejemplaridad” cervantina en “El celoso extremeño” / María Rosa Petruccelli – Reseñas bibliográficas

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Contenido: Intolerancia de la verdad y tolerancia del amor / La Dirección – Definición de la metafísica : sus dificultades y su posibilidad / Reginaldo Garrigou-Lagrange O. P. – La oposición estética forma-contenido / Manuel B. Trías – Ética de la subjetividad : en torno a la ética de G. Marcel y K. Jarspers /José Ignacio Alcorta -- Notas y comentarios -- Bibliografía

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We report the functional characterization of BipA, a GTPase that undergoes tyrosine phosphorylation in an enteropathogenic Escherichia coli (EPEC) strain. BipA mutants adhere to cultured epithelial cells but fail to trigger the characteristic cytoskeletal rearrangements found in cells infected with wild-type EPEC. In contrast, increased expression of BipA enhances actin remodelling and results in the hyperformation of pseudopods. BipA appears to be the first example of a new class of virulence regulator, as it also controls flagella-mediated cell motility and resistance to the antibacterial effects of a human host defence protein. Its striking sequence similarity to ribosome-binding elongation factors suggests that it uses a novel mechanism to modulate gene expression.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

High repetition rate passively mode-locked sources are of significant interest due to their potential for applications including optical clocking, optical sampling, communications and others. Due to their short excited state lifetimes mode-locked VECSELs are ideally suited to high repetition rate operation, however fundamentally mode-locked quantum well-based VECSELs have not achieved repetition rates above 10 GHz due to the limitations placed on the cavity geometry by the requirement that the saturable absorber saturates more quickly than the gain. This issue has been overcome by the use of quantum dot-based saturable absorbers with lower saturation fluences leading to repetition rates up to 50 GHz, but sub-picosecond pulses have not been achieved at these repetition rates. We present a passively harmonically mode-locked VECSEL emitting pulses of 265 fs duration at a repetition rate of 169 GHz with an output power of 20 mW. The laser is based around an antiresonant 6 quantum well gain sample and is mode-locked using a semiconductor saturable absorber mirror. Harmonic modelocking is achieved by using an intracavity sapphire etalon. The sapphire then acts as a coupled cavity, setting the repetition rate of the laser while still allowing a tight focus on the saturable absorber. RF spectra of the laser output show no peaks at harmonics of the fundamental repetition rate up to 26 GHz, indicating stable harmonic modelocking. Autocorrelations reveal groups of pulses circulating in the cavity as a result of an increased tendency towards Q-switched modelocking due to the low pulse energies.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Resumen: Esta ocasión me brinda la oportunidad de realizar algo más que un mero comentario a la Sentencia del Tribunal Europeo de Derechos Humanos (TEDH), “Costa y Pavan c/ Italia”. Es decir, voy a esbozar una toma de postura prescriptiva contraria a la filosofía individualista de fondo del TEDH respecto al presente caso, en base a un discurso jurídico-filosófico. La frivolidad del TEDH a la hora de tratar algunos temas de bioética y bioderecho se enmarca en el uso de un lenguaje políticamente correcto y de cierto consenso pragmático, recubierto en ocasiones de ropajes jurídico-formales, en lo concerniente al amplio artículo 8º del CEDH. Cuestiones vitales en la configuración de la realidad humana que deben tratarse desde una óptica comprometida con uno mismo y con el tiempo que le ha tocado vivir. Con semejante punto de vista resulta clave otorgar a las palabras un contenido, pero sobre ello siempre subyace el miedo a que las palabras acaben diciendo lo que nosotros queramos que digan. En el ámbito jurídico, en ocasiones, ese nosotros puede ser asumido por algún alto tribunal.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Coletânea sobre os antecedentes da Política Nacional do Petróleo e das atribuições do Conselho Nacional do Petróleo; incluindo legislação, discursos parlamentares, estudos especializados, memoriais, investigações oficiosas e particulares que permitem uma visão da história econômica do petróleo brasileiro. Reúne projetos, requerimentos e outros documentos parlamentares, do período de 1824 a 1957, que precederam ao projeto da Petrobrás, da tramitação na Câmara dos Deputados e no Senado Federal até à reunião do Congresso para decidir sobre o veto. Inclui inquéritos da comissão especializada sobre a Petrobrás em atividade.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Considerações acerca da contratação de empresa estrangeira para a construção de 16 prédios, em Brasília, para os Ministérios e, ainda, de uma represa e uma usina hidrelétrica.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Discussão do Projeto nº 1.773-A, de 1956, que fixa a data para a mudança da Capital Federal. Reafirmação dos argumentos favoráveis à mudança da Capital Federal do ponto de vista adinistrativo, social, político e econômico. Refutação dos argumentos de que a mudança da capital trará prejuízos insanáveis à cidade do Rio de Janeiro.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Discussão do Projeto nº 1.773-A, de 1956, que fixa a data para a mudança da Capital Federal. Descrédito quanto ao cumprimento do prazo para a mudança da Capital Federal, fundamentando sua tese com trecho de programa de governo do presidente Juscelino Kubitschek, do qual faz a leitura, onde S. Ex.a. afirma não ser possível a construção da Nova Capital em menos de quinze anos. Preocupação com o futuro do Rio de Janeiro, quando deixar de ser a Capital do país.