20,714 research outputs found

    Calibration, navigation, and registration of MAMS data for FIFE

    Get PDF
    The International Satellite Land Surface Climatology Project (ISLSCP) was conducted to study the interaction of the atmosphere with the land surface and the research problems associated with the interpretation of satellite data over the Earth's land surface. The experimental objectives of the First ISLSCP Field Experiment (FIFE) were the simultaneous acquisition of satellite, atmospheric, and surface data and to use these data to understand the processes controlling energy/mass exchange at the surface. The experiment site is a 15 x 15 km area southeast of Manhattan, Kansas, intersected by Interstate 70 and Kansas highway 177. The Konza Prairie portion is 5 x 5 km and is a controlled experiment site consisting primarily of native tall grass prairie vegetation. The remainder of the site is grazing and farm land with trees along creek beds that are scattered over the area. Airborne multispectral imagery from the Multispectral Atmospheric Mapping Sensor (MAMS) was collected over this region on two days during Intensive Field Campaign-1 (1FC-1) to study the time and space variability of remotely-sensed geophysical parameters. These datasets consist of multiple overflights covering about a 60-min period during late morning on June 4, 1987 and shortly after dark on the following day. Image data from each overpass were calibrated and Earth located with respect to each other using aircraft inertial navigation system parameters and ground control points. These were the first MAMS flights made with 10-bit thermal data

    Automated mesoscale winds derived from GOES multispectral imagery

    Get PDF
    An automated technique for extracting mesoscale winds from sequences of GOES VISSR image pairs was developed, tested and configured for quasi-real time/research applications on a computing system which gives mesoscale wind estimates at the highest spatial/temporal resolution possible from the VISSR imagery down to a wind vector separation of 10 km. Preprocessing of imagery using IR resampling, VIS edge preserving filtering, and reduced VIS resolution averaging improved height assignments and vector extraction for 10, 15, and 30 min imagery. An objective quality control system provides much greater than 99% accuracy in eliminating questionable wind estimates. Automated winds generally have better spatial coverage and density, and have random error estimates half as large as the manual winds. Dynamical analysis of cloud wind divergence revealed temporally consistent convergence centers on the meso beta scale that are highly correlated with on going and future developing convective storms. The entire system of computer codes was successfully vectorized for execution on an array processor resulting in job turnaround in less than one hour

    Institutionalizing health impact assessment in London as a public health tool for increasing synergy between policies in other areas

    Get PDF
    Objectives: To describe the background to the inclusion of health impact assessment (HIA) in the development process for the London mayoral strategies, the HIA processes developed, how these evolved, and the role of HIA in identifying synergies between and conflicting priorities of different strategies.Study design: Case series.Methods: Early HIAs had just a few weeks for the whole HIA process. A rapid appraisal approach was developed. Stages included: scoping, reviewing published evidence, a stakeholder workshop, drafting a report, review of the report by the London Health Commission, and submission of the final report to the Mayor. The process evolved as more assessments were conducted. More recently, an integrated impact assessment (IIA) method has been developed that fuses the key aspects of this HIA method with sustainability assessment, strategic environmental assessment and equalities assessment.Results: Whilst some of the early strategy drafts encompassed some elements of health, health was not a priority. Conducting HIAs was important both to ensure that the strategies reflected health concerns and to raise awareness about health and its determinants within the Greater London Authority (GLA). HIA recommendations were useful for identifying synergies and conflicts between strategies. HIA can be successfully integrated into other impact assessment processes.Conclusions: The HIAs ensured that health became more integral to the strategies and increased understanding of determinants of health and how the GLA impacts on health and health inequalities. Inclusion of HIA within IIA ensures that health and health inequalities impacts are considered robustly within statutory impact assessments. (C) 2010 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved

    Nesting symmetries and diffusion in disordered d-wave superconductors

    Get PDF
    The low-energy density of states (DOS) of disordered 2D d-wave superconductors is extremely sensitive to details of both the disorder model and the electronic band structure. Using diagrammatic methods and numerical solutions of the Bogoliubov-de Gennes equations, we show that the physical origin of this sensitivity is the existence of a novel diffusive mode with momentum close to (π,π)(\pi,\pi) which is gapless only in systems with a global nesting symmetry. We find that in generic situations, the DOS vanishes at the Fermi level. However, proximity to the highly symmetric case may nevertheless lead to observable non-monotonic behavior of the DOS in the cuprates

    A report on SHARP (Spacecraft Health Automated Reasoning Prototype) and the Voyager Neptune encounter

    Get PDF
    The development and application of the Spacecraft Health Automated Reasoning Prototype (SHARP) for the operations of the telecommunications systems and link analysis functions in Voyager mission operations are presented. An overview is provided of the design and functional description of the SHARP system as it was applied to Voyager. Some of the current problems and motivations for automation in real-time mission operations are discussed, as are the specific solutions that SHARP provides. The application of SHARP to Voyager telecommunications had the goal of being a proof-of-capability demonstration of artificial intelligence as applied to the problem of real-time monitoring functions in planetary mission operations. AS part of achieving this central goal, the SHARP application effort was also required to address the issue of the design of an appropriate software system architecture for a ground-based, highly automated spacecraft monitoring system for mission operations, including methods for: (1) embedding a knowledge-based expert system for fault detection, isolation, and recovery within this architecture; (2) acquiring, managing, and fusing the multiple sources of information used by operations personnel; and (3) providing information-rich displays to human operators who need to exercise the capabilities of the automated system. In this regard, SHARP has provided an excellent example of how advanced artificial intelligence techniques can be smoothly integrated with a variety of conventionally programmed software modules, as well as guidance and solutions for many questions about automation in mission operations

    LONGSHORE MOVEMENTS OF ADULT MALE JASUS LALANDII: EVIDENCE FROM LONG-TERM TAG RECAPTURES

    Get PDF
    Large-scale longshore movements (>10 km) of adult male Jasus lalandii (>70 mm carapace length) were examined on the west coast of South Africa using tag-recapture information from the period 1968 to 2000. The average rate of recovery of tagged rock lobsters was 15.7&#37 per fishing season. Only 0.48&#37 of 43 885 recaptured rock lobsters moved >10 km, 0.31&#37 southwards and 0.17&#37 northwards. The mean distance moved by those lobsters was 28.6 km and the mean time at liberty was 241.8 days. In recent years, densities of J.lalandii have increased substantially at the south-eastern end of their geographic range. The data indicate that this could not be attributable to a population migration of adult male rock lobsters from the west coast of South Africa. Afr. J. mar. Sci. 25: 387-39

    On the precision of chiral-dispersive calculations of ππ\pi\pi scattering

    Get PDF
    We calculate the combination 2a0(0)5a0(2)2a_0^{(0)}-5a_0^{(2)} (the Olsson sum rule) and the scattering lengths and effective ranges a1a_1, a2(I)a_2^{(I)} and b1b_1, b2(I)b_2^{(I)} dispersively (with the Froissart--Gribov representation) using, at low energy, the phase shifts for ππ\pi\pi scattering obtained by Colangelo, Gasser and Leutwyler (CGL) from the Roy equations and chiral perturbation theory, plus experiment and Regge behaviour at high energy, or directly, using the CGL parameters for aas and bbs. We find mismatch, both among the CGL phases themselves and with the results obtained from the pion form factor. This reaches the level of several (2 to 5) standard deviations, and is essentially independent of the details of the intermediate energy region (0.82E1.420.82\leq E\leq 1.42 GeV) and, in some cases, of the high energy behaviour assumed. We discuss possible reasons for this mismatch, in particular in connection with an alternate set of phase shifts.Comment: Version to appear in Phys. Rev. D. Graphs and sum rule added. Plain TeX fil

    Dark Solitons in Discrete Lattices: Saturable versus Cubic Nonlinearities

    Get PDF
    In the present work, we study dark solitons in dynamical lattices with the saturable nonlinearity and compare them with those in lattices with the cubic nonlinearity. This comparison has become especially relevant in light of recent experimental developments in the former context. The stability properties of the fundamental waves, for both on-site and inter-site modes, are examined analytically and corroborated by numerical results. Furthermore, their dynamical evolution when they are found to be unstable is obtained through appropriately crafted numerical experiments.Comment: 15 pages, 5 figure
    corecore