7,655 research outputs found

    The ability of the space telescope to detect extra-solar planetary systems

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    The space telescope can plan a key role in searching for and investigating the contents of extra-solar planetary systems. For about 90 nearby stars, positional variations due to major planets would be well within the astrometric capability of the wide-field/planetary camera system. Since the centroids of star images will be determined to within a milliarcsecond down to 22d magnitude, there will be an abundance of reference stars at very small angular distances from each planetary system candidate, and they will have small enough motions of their own to provide a reference frame of the stability required

    A study of cloud motions on Mars, part B Final report

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    Photographic plates used to map cloud motions on Mar

    Forum Shopping in Products Liability Actions: A Comparison Between the United States, France and Germany

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    The goal of this research is to state the current situation concerning products liability in the United States, the Federal Republic of Germany and more briefly, France and to compare the different systems. Emphasis will be given to the substantive laws, in particular to the new EC Directive and its adoption in the Federal Republic of Germany. Also, it will discuss the current German law, since this will be valid for all claims initiated before the enactment of the new ProdHaftG. Further, based on the previous analysis, it will be shown where a consumer is in the most favorable position to make out a claim against a foreign producer. Since the various parts of the chain of distribution are also subject to liability in products liability actions, their responsibility also will be described

    A Fresh Look at Energy, Materials, and Labor in Agriculture

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    An understanding of agriculture's energy, material, and labor requirements is essential for achieving economic and ecological sustainability, and for assessing the effectiveness of relevant policy decisions (biofuel subsidies, regulations, labeling, etc.). Previous studies of energy, materials, and labor use in farming have been based on either unverified voluntary reporting or test plots, rather than on the high-resolution measurements of mass and energy flows. Here we present a recursive analysis of 1.25 million data points describing in unprecedented detail the resource transactions on a 60 ha farm functioning for over 6 years. This analysis highlights the importance of accounting for all types of materials, as well as capital equipment, non-field labor, and commuting. The superior energy efficiency of the farm's energy-saving methods, including green manure, crop rotation, composting, and short-duration grazing -- compared with conventional methods -- persists even when the higher labor requirements are taken into account. One of the farm's methods, however -- the use of horses for traction -- is shown to be highly inefficient compared with mechanical tractors

    Studies in planetology, including the collection and interpretation of planetary information

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    The value of synoptic imaging of the planets is reported. The advantage of the Large Space Telescope, as compared with ground-based telescopes and planetary orbiters and flybys, is discussed. Desirable LST camera parameters and observing strategies are considered from the standpoint of synoptic imaging

    Cratering studies - Lunar surface-materials

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    Analytic model and basalt impact tests for correlating lunar crater properties with mass and velocity of impacting meteoroi

    Improving predictive power of physically based rainfall-induced shallow landslide models: a probabilistic approach

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    Distributed models to forecast the spatial and temporal occurrence of rainfall-induced shallow landslides are based on deterministic laws. These models extend spatially the static stability models adopted in geotechnical engineering, and adopt an infinite-slope geometry to balance the resisting and the driving forces acting on the sliding mass. An infiltration model is used to determine how rainfall changes pore-water conditions, modulating the local stability/instability conditions. A problem with the operation of the existing models lays in the difficulty in obtaining accurate values for the several variables that describe the material properties of the slopes. The problem is particularly severe when the models are applied over large areas, for which sufficient information on the geotechnical and hydrological conditions of the slopes is not generally available. To help solve the problem, we propose a probabilistic Monte Carlo approach to the distributed modeling of rainfall-induced shallow landslides. For the purpose, we have modified the Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability Analysis (TRIGRS) code. The new code (TRIGRS-P) adopts a probabilistic approach to compute, on a cell-by-cell basis, transient pore-pressure changes and related changes in the factor of safety due to rainfall infiltration. Infiltration is modeled using analytical solutions of partial differential equations describing one-dimensional vertical flow in isotropic, homogeneous materials. Both saturated and unsaturated soil conditions can be considered. TRIGRS-P copes with the natural variability inherent to the mechanical and hydrological properties of the slope materials by allowing values of the TRIGRS model input parameters to be sampled randomly from a given probability distribution. [..]Comment: 25 pages, 14 figures, 9 tables. Revised version; accepted for publication in Geoscientific Model Development on 13 February 201
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