669 research outputs found

    Letter from John B. Bayard to James B. Finley

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    Bayard tells of the break between the \u27Radicals\u27 and those of the \u27old faith.\u27 It seems that since Brothers Coston and Clarke have arrived at Pittsburgh, the people \u27\u27have taken fresh courage…and the Lord began to receive His works. George Brown is the leading Radical. Bayard has no doubt that Radicalism is on the wain. Abstract Number - 75https://digitalcommons.owu.edu/finley-letters/1073/thumbnail.jp

    A functional RNase P protein subunit of bacterial origin in some eukaryotes

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    RNase P catalyzes 5′-maturation of tRNAs. While bacterial RNase P comprises an RNA catalyst and a protein cofactor, the eukaryotic (nuclear) variant contains an RNA and up to ten proteins, all unrelated to the bacterial protein. Unexpectedly, a nuclear-encoded bacterial RNase P protein (RPP) homolog is found in several prasinophyte algae including Ostreococcus tauri. We demonstrate that recombinant O. tauri RPP can functionally reconstitute with bacterial RNase P RNAs (RPRs) but not with O. tauri organellar RPRs, despite the latter’s presumed bacterial origins. We also show that O. tauri PRORP, a homolog of Arabidopsis PRORP-1, displays tRNA 5′-processing activity in vitro. We discuss the implications of the striking diversity of RNase P in O. tauri, the smallest known free-living eukaryote.Ministerio de Ciencia e Innovación European Regional Fund BFU2007-60651Junta de Andalucía P06-CVI-01692National Science Foundation MCB-0238233 MCB-0843543European Union ASSEMBLE 22779

    Jet photonique simple ou double pour la détection d'objets sub-longueur d'onde

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    National audienceOn appelle « jet photonique » un faisceau électromagnétique ayant une grande concentration de puissance en champ proche. Ce jet photonique possède des propriétés comme une faible divergence et une faible largeur à mi-hauteur. Il peut être appliqué pour la détection d'objet de taille sub-longueur d'onde. Les jets photoniques peuvent être observés pour des longueurs d'onde optiques dans le voisinage d'une sphère diélectrique micrométrique. Ils peuvent être obtenus également dans la gamme des microondes. Dans cet article, nous montrons la réalisation et la mise en évidence de ces jets photoniques dans la gamme microondes. La modélisation développée a permis de mettre en oeuvre des systèmes produisant des jets simples ou doubles. L'expérimentation et ses résultats sont présentés et la détection facile d'objets de faible taille devant la longueur d'onde est mise en évidence ainsi que la mise en évidence de leur mouvement

    System Identification of a Nonlinear Mode for the Shuttle Radar Topography Mission

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    A study is presented to identify a nonlinear bending mode for a 60-m space structure. This study was done in support of the Shuttle Radar Topography Mission (SRTM) and postflight height reconstruction efforts. For this purpose, one linear model and three nonlinear models of the structural mode were considered and evaluated. The best model was determined based on in-flight data collected during the mission and was implemented as part of the final ground software that was used for reconstructing relative radar antenna motion for the SRTM interferometer payload. High accuracy estimates of the relative states were essential for supporting the motion compensation algorithm used in the radar interferometry processor for calculating the desired topographic maps. The improvement resulting fromidentifying nonlinear modal behavior contributed to meeting mission performance requirements

    Numerical Analysis on the Optimisation of Thermal Comfort Levels in an Office Located inside a Historical Building

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    The present study examines the possibility of thermal comfort optimisation inside an office room where, due to historical heritage, it is possible to modify neither the energetic characteristic of the envelope nor the position of the inlet air vents. The distribution of global and local thermal comfort indices is evaluated in both heating and cooling conditions by establishing a computational fluid dynamics (CFD) model validated against experimental data. The obtained results demonstrate a striking asymmetry of the air velocity and temperature distribution due to the low energy efficiency of the building. In heating mode, the predicted mean vote (PMV) values were improved if the discharged air from the fan coil was at its maximal velocity. However, at the same time, the vertical air temperature gradient increased by around 0.5 C in each working station. In the cooling condition, in the absence of the solar radiation, the minimal air-flow rate satisfied the acceptable range of the draught rate (DR), whereas in the presence of a solar load, it could not meet the required cooling load in all positions, leading to higher floor temperature. The findings of this study allow for identifying and rearranging the optimal position of working stations in terms of thermal comfort

    Influence of different heating systems on thermal comfort perception: a dynamic and CFD analysis

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    In this paper, we investigate the influence of different heating systems on the thermal comfort indexes, Predicted Mean Vote (PMV) and Predicted Percentage of Dissatisfied (PPD), for a residential apartment located in Bologna (Italy). The apartment has an area of 40 m2 and is located on the ground floor of 4 floors building. The envelop consists in horizontal perforated bricks with internal thermal insulation material and two windows. The analyses are performed employing Trnsys, a commercial dynamic simulation software and Simcenter STAR-CCM+, a multiphysics computational fluid dynamics (CFD) software. The CFD analysis regards a steady condition of a typical winter day in Bologna. Thermal comfort indexes and thermal energy demand are studied comparing two different heating generation systems existing in the considered apartment: a condensing gas boiler coupled with radiators as terminal emitters and an air-to-air heat pump. By crossing the results obtained by the dynamical approach and by the CFD simulations, a two-objective methodology where energy consumption is minimised while thermal comfort is obtained, is presented

    Electromagnetic jet for characterization applications

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    This comparative study allows to evaluate the performance of an electromagnetic jet to determine the electromagnetic response of materials, without being in usual far field conditions. In this work, the reflection coefficient of a substrate with ground plane, calculated analytically, is compared with that determined in simulation by the electromagnetic jet. The results show a satisfactory agreement after calibrating the simulated reflection coefficient at the focal point of the jet. Thus, we were able to find, by a local measurement, data consistent with a classical free space type measurement.Comment: in French language. 17{\`e}mes Journ{\'e}es de Caract{\'e}risation Microondes et Mat{\'e}riaux, Laboratoire GREMAIN; CEA Le Ripault, Apr 2023, TOURS, Franc

    Focal plane calibration of the Spitzer space telescope

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    The Spitzer space telescope (Spitzer) is currently NASA's largest and most sensitive infrared (IR) telescope in space. Spitzer's focal plane carries detectors from three science instruments, namely, the infrared array camera (IRAC), the infrared spectrograph (IRS), and the multiband imaging photometer for Spitzer (MIPS). In this article we discuss the instrument pointing frame (IPF) Kalman filter, which is used to calibrate Spitzer's telescope focal plane. The IPF filter is a high-order square-root iterated linearized Kalman filter that carries 37 states to estimate frame misalignments, while correcting for systematic errors due to optical distortions, scan-mirror errors, thermomechanically induced drift variations, and gyro bias and drift in all axes. The Spitzer application demonstrates that the integrated approach offers significant advantages with respect to optimality, time-efficiency, anomaly detection, and health monitoring compared to existing telescope-calibration approaches, where the parameters are artificially broken into subsets that are estimated by separate teams of analysts. Performance results for the IPF Kalman filter indicate that all Spitzer calibration requirements are satisfied, and are consistent with margins predicted by preflight error analysis. On a final note, after more than five-and-a-half years of probing the cool cosmos, Spitzer entered standby mode on May 15, 2009, as a result of running out of the liquid helium coolant that kept its infrared instruments chilled. This event marks the successful completion of the Spitzer's cold mission as originally commissioned by NASA. However, even though the telescope is warming up, the IRAC arrays continue to operate and provide useful scientific data. A new follow-on warm mission based on the IRAC arrays has been defined and initiated, so that Spitzer will remain in commission for several years to come

    Framing the Narrative: Female Fighters, External Audience Attitudes, and Transnational Support for Armed Rebellions

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    Female combatants play a central role in rebel efforts to cultivate and disseminate positive narratives regarding the movement and its political goals. Yet, the effectiveness of such strategies in shaping audience attitudes or generating tangible benefits for the group remains unclear. We propose and test a theory regarding the channels through which female fighters advance rebel goals. We argue that female fighters positively influence audience attitudes toward rebel groups by strengthening observers’ beliefs about their legitimacy and their decision to use armed tactics. We further contend that these effects directly help them secure support from transnational non-state actors and indirectly promote state support. We assess our arguments by combining a novel survey experiment in two countries with analyses of new cross-national data on female combatants and information about transnational support for rebels. The empirical results support our arguments and demonstrate the impact of gender framing on rebel efforts to secure support
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