1,617 research outputs found

    Absorption of sunlight in the atmosphere of Venus

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    The profiles of upward, downward and net solar flux on Venus were measured at altitudes from about 62 km to the surface in three spectral bands at a vertical resolution of a few hundred meters. These data measured the penetration and absorption of solar energy in Venus' lower atmosphere quantities that are essential in evaluating the role of the greenhouse mechanism in supporting Venus' remarkably high surface temperature. In addition, the data constrained the vertical structure and optical properties of the Venus clouds

    The single scattering phase functions of Jupiter's clouds

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    The determination of the single scattering phase functions of Jupiter's clouds and a thin upper haze by Tomasko et al. was refined and extended to seven latitudes in blue and red light. The phase function is well-constrained by the Pioneer 10 and 11 photometric data sets. Multiple scattering models were computed to match the limb darkening at each latitude at up to 15 phase angles from 12 deg to 151 deg. Ground-based observations were used for absolute calibration and to extend the data to lower phase angles. The phase functions were parameterized using the double Henyey-Greenstein function. The three Henyey-Greenstein parameters and the single scattering albedo were determined using a non-linear least squares method for the haze and the clouds below. The phase functions derived for the northen zone and belt are remarkably similar to the phase functions of the corresponding regions in the south, with most of the differences in brightness of the northern and southern features resulting from minor differences in single scattering albedo. Analysis of the Equatorial Region is complicated by the presence of numerous small features, but the phase function required is generally similar to that seen in the more homogeneous regions. Details of the phase functions of the haze and clouds are presented, and the differences between the cloud phase functions at low and high latitudes in red and blue light are discussed

    Sensing ligand binding to a clinically relevant lectin by tryptophan fluorescence anisotropy

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    Increasing insights into the involvement of endogenous lectins in disease processes fuel the interest to develop potent inhibitors. As a consequence, robust assay procedures are required. Due to their activity as adhesion/growth-regulatory effectors this study focussed on galectins. The human proto-type galectin-1 was selected as representative of this family with conserved presence of a tryptophan moiety in the binding site. This structural feature was taken advantage of to establish its use as reporter for ligand contact measuring polarized fluorescence emission. The experimentally determined anisotropy r0 was about 0.2, altered by about 5% in the presence of the cognate disaccharide lactose. This parameter change enabled calculating the equilibrium binding constant and kinetic rate constants. The detailed analysis of the depolarization process further indicated fast conformational dynamics within the binding site. Since an inherent property of the protein was exploited, no labeling is needed. Owing to tryptophan’s presence in carbohydrate-binding sites, also in other classes of lectins as well as in carbohydrate-binding modules and glycoenzymes (glycosyltransferases, glycosidases), this assay procedure can have relevance beyond galectins

    Modelling Aspects of Planar Multi-Mode Antennas for Direction-of-Arrival Estimation

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    Multi-mode antennas are an alternative to classical antenna arrays, and hence a promising emerging sensor technology for a vast variety of applications in the areas of array signal processing and digital communications. An unsolved problem is to describe the radiation pattern of multi-mode antennas in closed analytic form based on calibration measurements or on electromagnetic field (EMF) simulation data. As a solution, we investigate two modeling methods: One is based on the array interpolation technique (AIT), the other one on wavefield modeling (WM). Both methods are able to accurately interpolate quantized EMF data of a given multi-mode antenna, in our case a planar four-port antenna developed for the 6-8.5 GHz range. Since the modeling methods inherently depend on parameter sets, we investigate the influence of the parameter choice on the accuracy of both models. Furthermore, we evaluate the impact of modeling errors for coherent maximum-likelihood direction-of-arrival (DoA) estimation given different model parameters. Numerical results are presented for a single polarization component. Simulations reveal that the estimation bias introduced by model errors is subject to the chosen model parameters. Finally, we provide optimized sets of AIT and WM parameters for the multi-mode antenna under investigation. With these parameter sets, EMF data samples can be reproduced in interpolated form with high angular resolution

    Validation of real-time properties of a robotic software architecture

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    National audienceIn this paper, we propose a mechanism allowing to evaluate the schedulability of a robotic software architecture, and then validate its real-time properties. The robotic software architecture is described through a Domain Specific Language (DSL), MAUVE, that allows to model communicating components. The evaluation of schedulability of the architecture consists in first computing the Worst-Case Execution Time (WCET) of the elementary functions of the components. Then the Worst Case Response Time (WCRT) of the component is computed from the elementary WCET and the component models, allowing to validate the schedulatiblity of the architecture. We illustrate our methodology on the evaluation of a control architecture for a ground mobile robot

    Mauve: a Component-based Modeling Framework for Real-time Analysis of Robotic Applications.

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    Robots are more and more used in very diverse situations (services to persons, military missions, crisis management, . . . ) in which robots must give some guarantees of safety and reliability. To be really integrated in everyday life, robots must fulfil some requirements. Among these requirements, we focus on the nonfunctional requirements on embedded software [1], and more specifically on real-time software requirements. These requirements are most of the time fulfilled by proving the schedulability of the embedded software. Analysing and validating such properties on an existing hand-coded software requires some reverse modelling of the software, leading to approximations of its behaviour. These approximations may have certification authorities not be confident on the robot dependability. This paper proposes an integrated development methodology that starts from software component modelling, and leads to both validation of the embedded software and generation of deployable embedded software

    Lunar maria and related deposits: Preliminary Galileo imaging results

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    During the Earth-Moon flyby the Galileo Solid State Imaging system obtained new information on lunar media. Imaging data in spectral bands from 0.4 to 1.0 micron wavelength provide color data for deposits on the western limb. General objectives were to determine the composition and stratigraphy of mare and related deposits for areas not previously seen well in color, and to compare the results with well-studied nearside maria. Initial results from images reduced with preliminary calibrations show that Galileo spectral reflectance data are consistent with previous earthbased observations

    When this is over

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    A poem about priorities When this is over Will we still wash our hands as often as we do now or can we go back to playing with dirt all day without panicking?...https://mosaic.messiah.edu/covid/1017/thumbnail.jp

    The Scottish Road to Net Zero: Corporate Welfare and Assetization Cascades

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    As climate change mitigation efforts intensify, land-based solutions such as carbon sequestration and biodiversity enhancement are emerging as a key strategy requiring substantial financial investment. This paper examines the current Scottish approach to achieving net zero, highlighting the role of corporate welfare in shaping market development. Using interviews and document analysis in a process tracing design, the study shows how the private sector plays a key role in leading and shaping climate change mitigation efforts such as voluntary carbon codes and public programs to fund them. It introduces the concept of assetization cascades to capture how corporate welfare initiatives support and drive the creation of new natural capital assets by drawing in more actors that engage in assetization. The findings contribute to the literature on corporate welfare, assetization and the evolving role of the state in climate governance.Introduction Land-based solutions to climate change Corporate welfare and climate finance: Dynamics between state and private sector Methodology, data and the Scottish case Scotland and its journey to net zero Conclusion Acknowledgments Footnote References Supplementary Materia

    The United Nations Definition of Aggression: A Preliminary Analysis

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