984 resultados para Coolidge, Cornelius--1778-1843
Resumo:
Aerosol absorption is poorly quantified because of the lack of adequate measurements. It has been shown that the Ozone Monitoring Instrument (OMI) aboard EOS-Aura and the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard EOS-Aqua, which fly in formation as part of the A-train, provide an excellent opportunity to improve the accuracy of aerosol retrievals. Here, we follow a multi-satellite approach to estimate the regional distribution of aerosol absorption over continental India for the first time. Annually and regionally averaged aerosol single-scattering albedo over the Indian landmass is estimated as 0.94 +/- 0.03. Our study demonstrates the potential of multi-satellite data analysis to improve the accuracy of retrieval of aerosol absorption over land.
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Sensory receptors determine the type and the quantity of information available for perception. Here, we quantified and characterized the information transferred by primary afferents in the rat whisker system using neural system identification. Quantification of ``how much'' information is conveyed by primary afferents, using the direct method (DM), a classical information theoretic tool, revealed that primary afferents transfer huge amounts of information (up to 529 bits/s). Information theoretic analysis of instantaneous spike-triggered kinematic stimulus features was used to gain functional insight on ``what'' is coded by primary afferents. Amongst the kinematic variables tested-position, velocity, and acceleration-primary afferent spikes encoded velocity best. The other two variables contributed to information transfer, but only if combined with velocity. We further revealed three additional characteristics that play a role in information transfer by primary afferents. Firstly, primary afferent spikes show preference for well separated multiple stimuli (i.e., well separated sets of combinations of the three instantaneous kinematic variables). Secondly, neurons are sensitive to short strips of the stimulus trajectory (up to 10 ms pre-spike time), and thirdly, they show spike patterns (precise doublet and triplet spiking). In order to deal with these complexities, we used a flexible probabilistic neuron model fitting mixtures of Gaussians to the spike triggered stimulus distributions, which quantitatively captured the contribution of the mentioned features and allowed us to achieve a full functional analysis of the total information rate indicated by the DM. We found that instantaneous position, velocity, and acceleration explained about 50% of the total information rate. Adding a 10 ms pre-spike interval of stimulus trajectory achieved 80-90%. The final 10-20% were found to be due to non-linear coding by spike bursts.
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In eubacteria, RecA is essential for recombinational DNA repair and for stalled replication forks to resume DNA synthesis. Recent work has implicated a role for RecA in the development of antibiotic resistance in pathogenic bacteria. Consequently, our goal is to identify and characterize small-molecule inhibitors that target RecA both in vitro and in vivo. We employed ATPase, DNA strand exchange and LexA cleavage assays to elucidate the inhibitory effects of suramin on Mycobacterium tuberculosis RecA. To gain insights into the mechanism of suramin action, we directly visualized the structure of RecA nucleoprotein filaments by atomic force microscopy. To determine the specificity of suramin action in vivo, we investigated its effect on the SOS response by pull-down and western blot assays as well as for its antibacterial activity. We show that suramin is a potent inhibitor of DNA strand exchange and ATPase activities of bacterial RecA proteins with IC50 values in the low micromolar range. Additional evidence shows that suramin inhibits RecA-catalysed proteolytic cleavage of the LexA repressor. The mechanism underlying such inhibitory actions of suramin involves its ability to disassemble RecA-single-stranded DNA filaments. Notably, suramin abolished ciprofloxacin-induced recA gene expression and the SOS response and augmented the bactericidal action of ciprofloxacin. Our findings suggest a strategy to chemically disrupt the vital processes controlled by RecA and hence the promise of small molecules for use against drug-susceptible as well as drug-resistant strains of M. tuberculosis for better infection control and the development of new therapies.
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Interferon-gamma (Ifn gamma), a known immunomodulatory cytokine, regulates cell proliferation and survival. In this study, the mechanisms leading to the selective susceptibility of some tumor cells to Ifn gamma were deciphered. Seven different mouse tumor cell lines tested demonstrated upregulation of MHC class I to variable extents with Ifn gamma; however, only the cell lines, H6 hepatoma and L929 fibrosarcoma, that produce higher amounts of nitric oxide (NO) and reactive oxygen species (ROS) are sensitive to Ifn gamma-induced cell death. NO inhibitors greatly reduce Ifn gamma-induced ROS; however, ROS inhibitors did not affect the levels of Ifn gamma-induced NO, demonstrating that NO regulates ROS. Consequently, NO inhibitors are more effective, compared to ROS inhibitors, in reducing Ifn gamma-induced cell death. Further analysis revealed that Ifn gamma induces peroxynitrite and 3-nitrotyrosine amounts and a peroxynitrite scavenger, FeTPPS, reduces cell death. Ifn gamma treatment induces the phosphorylation of c-jun N-terminal kinase (Jnk) in H6 and L929 but not CT26, a colon carcinoma cell line, which is resistant to Ifn gamma-mediated death. Jnk activation downstream to NO leads to induction of ROS, peroxynitrite and cell death in response to Ifn gamma. Importantly, three cell lines tested, i.e. CT26, EL4 and Neuro2a, that are resistant to cell death with Ifn gamma alone become sensitive to the combination of Ifn gamma and NO donor or ROS inducer in a peroxynitrite-dependent manner. Overall, this study delineates the key roles of NO as the initiator and Jnk, ROS, and peroxynitrite as the effectors during Ifn gamma-mediated cell death. The implications of these findings in the Ifn gamma-mediated treatment of malignancies are discussed. (C) 2014 Elsevier B.V. All rights reserved.
Resumo:
Interferon-gamma (Ifn gamma), a known immunomodulatory cytokine, regulates cell proliferation and survival. In this study, the mechanisms leading to the selective susceptibility of some tumor cells to Ifn gamma were deciphered. Seven different mouse tumor cell lines tested demonstrated upregulation of MHC class I to variable extents with Ifn gamma; however, only the cell lines, H6 hepatoma and L929 fibrosarcoma, that produce higher amounts of nitric oxide (NO) and reactive oxygen species (ROS) are sensitive to Ifn gamma-induced cell death. NO inhibitors greatly reduce Ifn gamma-induced ROS; however, ROS inhibitors did not affect the levels of Ifn gamma-induced NO, demonstrating that NO regulates ROS. Consequently, NO inhibitors are more effective, compared to ROS inhibitors, in reducing Ifn gamma-induced cell death. Further analysis revealed that Ifn gamma induces peroxynitrite and 3-nitrotyrosine amounts and a peroxynitrite scavenger, FeTPPS, reduces cell death. Ifn gamma treatment induces the phosphorylation of c-jun N-terminal kinase (Jnk) in H6 and L929 but not CT26, a colon carcinoma cell line, which is resistant to Ifn gamma-mediated death. Jnk activation downstream to NO leads to induction of ROS, peroxynitrite and cell death in response to Ifn gamma. Importantly, three cell lines tested, i.e. CT26, EL4 and Neuro2a, that are resistant to cell death with Ifn gamma alone become sensitive to the combination of Ifn gamma and NO donor or ROS inducer in a peroxynitrite-dependent manner. Overall, this study delineates the key roles of NO as the initiator and Jnk, ROS, and peroxynitrite as the effectors during Ifn gamma-mediated cell death. The implications of these findings in the Ifn gamma-mediated treatment of malignancies are discussed. (C) 2014 Elsevier B.V. All rights reserved.
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Multifrequency atomic force microscopy is a powerful nanoscale imaging and characterization technique that involves excitation of the atomic force microscope (AFM) probe and measurement of its response at multiple frequencies. This paper reports the design, fabrication, and evaluation of AFM probes with a specified set of torsional eigen-frequencies that facilitate enhancement of sensitivity in multifrequency AFM. A general approach is proposed to design the probes, which includes the design of their generic geometry, adoption of a simple lumped-parameter model, guidelines for determination of the initial dimensions, and an iterative scheme to obtain a probe with the specified eigen-frequencies. The proposed approach is employed to design a harmonic probe wherein the second and the third eigen-frequencies are the corresponding harmonics of the first eigen-frequency. The probe is subsequently fabricated and evaluated. The experimentally evaluated eigen-frequencies and associated mode shapes are shown to closely match the theoretical results. Finally, a simulation study is performed to demonstrate significant improvements in sensitivity to the second-and the third-harmonic spectral components of the tip-sample interaction force with the harmonic probe compared to that of a conventional probe.
Resumo:
使用自行设计的的真空实验装置,采用一维实验室土柱实验方法在不同实验条件下进行了15组实验,并基于实验所得的穿透曲线,使用梯度正则化方法反演得到了镉离子在8种葡萄牙土样和1种比利时土样中相应的传输模型参数.同时通过数值模拟实验验证了梯度正则化方法的有效性和可靠性,进而证明所得结果是有效的.
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A general method is presented for solving the plane elasticity problem of finite plates with multiple microcracks. The method directly accounts for the interactions between different microcracks and the effect of outer boundary of a finite plate. Analysis is based on a superposition scheme and series expansions of the complex potentials. By using the traction-free conditions on each crack surface and resultant forces relations along outer boundary, a set of governing equations is formulated. The governing equations are solved numerically on the basis of a boundary collocation procedure. The effective Young's moduli for randomly oriented cracks and parallel cracks are evaluated for rectangular plates with microcracks. The numerical results are compared with those from various micromechanics models and experimental data. These results show that the present method provides a direct and efficient approach to deal with finite solids containing multiple microcracks.
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El presente trabajo se realizó con la finalidad de determinar el efecto de arreglos de siembra (0.3 metro entre surco por 5 plantas por metro lineal 0.4 metro entre surco por 7 plantas por metro lineal; 0.5 metro entre surco por 10 plantas por metro lineal 0.7 metro entre surco por 15 plantas por metro lineal ; 0.8 metro entre surco por 18 plantas por metro lineal 0.9 metro entre surco por 23 plantas por metro lineal) sobre el crecimiento y rendimiento del cultivo del sorgo (Sorghum bicolor L.) en la variedad Pinolero, bajo las condiciones ecológicas de la finca La Concepción, Nagarote León. El ensayo se estableció en la siembra de postrera de 1999, utilizándose un diseño de bloques completos al azar con cuatro repeticiones. Los componentes de crecimiento (altura, diámetro y hojas por planta) presentaron diferencias significativas a los 45, 60 y 75 días después de la siembra De las variables evaluadas para el rendimiento y sus principales componentes, se encontraron diferencias significativas para las variables ramillas/panoja, granos/ramillas, granos/panoja, plantas acamadas/ha, plantas cosechadas/ha y rendimiento de grano. Los resultados de los análisis de varianza y económico indican que el arreglo de siembra 0.5 metro entre surco por 10 plantas por metro lineal, se obtuvo el mayor rendimiento (4,975.0 kg/ha) y la más alta rentabilidad económica, con una tasa de retomo marginal del 297 por ciento.
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La presente investigación se llevó a efecto en el Km 14 de la carretera Norte, en el Centro Nacional de Investigación Agropecuaria (CNIA – INTA), 2 Km. al sur en el municipio de Managua, departamento de Managua. El ensayo se estableció en la época de postrera del 2001, en suelos de origen volcánico y textura franco arenosa. El propósito del experimento fue evaluar de forma preliminar 19 líneas de sorgo Sorghum bicolor (L) Moench por su reacción a la mosquita del sorgo ( Stenodiplosis sorghicola Coquillet), el cogollero ( Spodoptera frugiperda J:E:Smith) y enfermedades. Los materiales utilizados son parte de un ADIN (All Diseases and Insect Nursery). La parcela experimental tuvo un tamaño de 3.75 m 2 y constó de 1 surco de 5 metros lineales (1 línea por surco). El ensayo se estableció utilizando la metodología de la Universidad de Texas A & M con19 tratamientos (líneas) y 2 repeticiones. Las variables evaluadas fueron: a) daño foliar causado por el gusano cogollero ( Spodoptera frugiperda J. E. Smith ), b) días a floración, c) número de mosquitas d el sorgo ( Stenodiplosis sorghicola Coquillett ) por panoja, d) número de parasitoides de mosquita del sorgo ( Aprostocetus diplosidis Crawford) por panoja, e) severidad de las enfermedades foliares y vasculares. Para la primera y la última variable se utilizó la escala de daño propuesta por la Universidad de Texas A & M. A estos datos se les efectuó un análisis estadístico descriptivo. Para las variables b, c y d se realizó un análisis de varianza y prueba de rangos múltiples de Duncan (P ≤ 0.05), además se les efectuó un análisis de correlación de Pearson. En cuanto al daño foliar causado por el gusano cogollero ( Spodoptera frugiperda J. E. Smith ), no existieron diferencias en el comportamiento de las líneas. Este aspecto no representó una incidencia relevante. Con respecto al período de floración, la línea 96CA5986 presentó el mayor número de días a floración, en tanto que la línea Tx2880 presentó el menor número de días a floración. Los resultados obtenidos indican que el comportamiento de las 19 líneas de sorgo [ Sorghum bicolor ( L.) Moench ] ante el ataque de mosquita del sorgo ( Stenodiplosis sorghicola Coquillett ) y la incidencia de su parasitoide ( Aprostocetus diplosidis Crawford ) es similar para cada línea; La línea 98BRON122 fue la que presentó el mayor valor con respecto a esta variable, mientras que la línea que presentó el menor número de mosquitas por panoja fue B9104; Existe relación entre la variable número de mosquitas ( Stenodiplosis sorghicola Coquillett ) por panoja y días a floración y esta relación es afectada por el parasitoide de la mosquita ( Aprostocetus diplosidis Crawford ). Puede identificarse que la Linea 87EO366*9EO328 fue la que presentó la mayor severidad de enfermedades foliares tales como antracnosis ( Colletotrichum graminicola G. W. Wilson ), mancha zonada ( Gloeocercospora sorghi D.Bain.& Edgerton ex Deighton) , mancha gris de la hoja (Cercospora sorghi Ellis y Everth) tizón de la hoja ( Exserohilum turcicum (pass.). La línea que presentó la menor severidad fue 94B1055. La enfermedad que presentó mayor severidad en el ensayo fue Antracnosis.
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<正> 流体的湍流运动普遍存在于大气、海洋、飞行器周围、推进装置和流体机械中,探讨湍流形成的条件和过程是流动稳定性理论的研究对象。 早在1843年,Stokes就预见到流体状态转捩的原因是失稳。整整100年前(1883年),Reynolds让液体流入不同口径的圆管,并在对称轴上注入一股纤细的颜色水,以便明显、敏感地观察到湍流的发生。他发现: (1)流速较低时,可以看到层次分明的层流,流速增加到一定程度后,就转变成高度无序的湍流状态;
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v. 1. Assembléia Geral Constituinte e Legislativa (1823) -- v. 2. Câmara dos Deputados(1826-1829) -- v. 3. Câmara dos Deputados (1830-1842) -- v. 4. Câmara dos Deputados (1843-1862) -- v. 5. Câmara dos Deputados (1861-1889) : índice de pessoas, índice de assuntos. No v. 5 inclui dicionário biobibliográfico dos eclesiásticos que participaram, com ao menos uma intervenção, dos debates parlamentares.
Resumo:
Analisa as repercussões sociais e os sucedâneos jurídicos à falta de regulamentação em lei de usos e costumes, já incorporados ao modus vivendi da sociedade, de populações de orientação sexual minoritária. Toma-se como paradigma dessa situação, o Projeto de lei nº 1.151/1995, de autoria da ex-deputada federal Marta Suplicy, que visa a instituir a união civil homossexual, reformada depois para parceria civil registrada entre pessoas do mesmo sexo. Tramitando há mais de 13 anos na Câmara dos Deputados, e aprovado por unanimidade pela Comissão Especial que o analisou, aguarda penosamente a apreciação do Plenário daquela Casa de Leis. Por isso, desamparados em suas demandas, os atores sociais envolvidos buscam outros foros onde possam ser ouvidos.
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Balanço do primeiro ano de funcionamento da Assembleia Nacional Constituinte (ANC). Retrospectiva da instalação da ANC, da declaração do Ministro do Supremo Tribunal Federal, José Carlos Moreira Alves, da eleição do Presidente e manifestação de Deputados Constituintes. Início da votação do Título II.
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[EN] In this paper I offer a new edition of the Euskera manuscript, written by the bascologist J.F. Aizkibel in 1856. The preliminary study focuses on a survey of the sources extensively used by Aizkibel, which are mainly two: Schleicher's Die Sprachen Europas (1850 [1852]) and Champollion-Figeac's Égypte ancienne (1840). Moreover, the comparison with the sources reveals us that Aizkibel intended to adapt Schleicher’s and Champollion-Figeac's analyses to attest that Basque was originally a very ancient monosyllabic language, and that it was spoken by cultured people. Some other linguistic ideas of Aizkibel are also discussed.