295 research outputs found

    The environmental vegetation index: A tool potentially useful for arid land management

    Get PDF
    The NOAA-6 AVHRR data sets acquired over South Texas and Mexico during the spring of 1980 and after Hurricane Allen passed inland are analyzed. These data were processed to produce the Gray-McCrary Index (GMI's) for each pixel location over the selected area, which area contained rangeland and cropland, both irrigated and nonirrigated. The variations in the GMI's appear to reflect well the availability of water for vegetation. The GMI area maps are shown to delineate and to aid in defining the duration of drought; suggesting the possibility that time changes over a selected area could be useful for irrigation management

    Advanced Very High Resolution Radiometer (AVHRR) data evaluation for use in monitoring vegetation. Volume 1: Channels 1 and 2

    Get PDF
    Data from the National Oceanic and Atmospheric Administration satellite system (NOAA-6 satellite) were analyzed to study their nonmeteorological uses. A file of charts, graphs, and tables was created form the products generated. It was found that the most useful data lie between pixel numbers 400 and 2000 on a given scan line. The analysis of the generated products indicates that the Gray-McCrary Index can discern vegetation and associated daily and seasonal changes. The solar zenith-angle correction used in previous studies was found to be a useful adjustment to the index. The METSAT system seems best suited for providing large-area analyses of surface features on a daily basis

    Meteorological satellite data: A tool to describe the health of the world's agriculture

    Get PDF
    Local area coverage data acquired aboard the TIROS-N satellite family by the advanced very high resolution radiometer systems was examined to determine the agricultural information current. Albedo differences between channel 2 and channel 1 of the advanced very high resolution radiometer LAC (called EVI) are shown to be closely correlated to the Ashburn vegetative index produced from LANDSAT multispectral scanner data which have been shown to vary in response to "greenness", soil moisture, and crop production. The statistical correlation between the EVI and the Ashburn Vegetative Index (+ or - 1 deg) is 0.86

    Characteristics, of TIROS, GOES, DMSP and LANDSAT Systems

    Get PDF
    The characteristics of the TIROS, GOES, DMSP and LANDSAT systems of satellites are described. The data listed for each system are altitude of orbit, inclination/position, orbit type, orbits per day, expected operational lifetime and the sensor systems. The sensor systems are described as to wavelength of each channel, resolution, field of view and other pertinent information. Data information such as availability rate, collection method, primary use/application and how to obtain additional information is also given

    Crater lake cichlids individually specialize along the benthic-limnetic axis

    Get PDF
    A common pattern of adaptive diversification in freshwater fishes is the repeated evolution of elongated open water (limnetic) species and high-bodied shore (benthic) species from generalist ancestors. Studies on phenotype-diet correlations have suggested that population-wide individual specialization occurs at an early evolutionary and ecological stage of divergence and niche partitioning. This variable restricted niche use across individuals can provide the raw material for earliest stages of sympatric divergence. We investigated variation in morphology and diet as well as their correlations along the benthic-limnetic axis in an extremely young Midas cichlid species, Amphilophus tolteca, endemic to the Nicaraguan crater lake Asososca Managua. We found that A. tolteca varied continuously in ecologically relevant traits such as body shape and lower pharyngeal jaw morphology. The correlation of these phenotypes with niche suggested that individuals are specialized along the benthic-limnetic axis. No genetic differentiation within the crater lake was detected based on genotypes from 13 microsatellite loci. Overall, we found that individual specialization in this young crater lake species encompasses the limnetic- as well as the benthic macro-habitat. Yet there is no evidence for any diversification within the species, making this a candidate system for studying what might be the early stages preceding sympatric divergence

    What a difference a term makes:the effect of educational attainment on marital outcomes in the UK

    Get PDF
    Abstract In the past, students in England and Wales born within the first 5 monthsof the academic year could leave school one term earlier than those born later inthe year. Focusing on women, those who were required to stay on an extra termmore frequently hold some academic qualification. Using having been required tostay on as an exogenous factor affecting academic attainment, we find that holding alow-level academic qualification has no effect on the probability of being currentlymarried for women aged 25 or above, but increases the probability of the husbandholding some academic qualification and being economically active.33 Halama

    the use of administrative data to evaluate the impact of active labor market policies the case of the italian liste di mobilita

    Get PDF
    Administrative data are a valuable source of information in several ways for the design of an impact evaluation. Conditional on providing the information required for the evaluation, they feature major advantages: they cover the whole (sub)population of reference for their administrative purposes, and not just a sample of individuals; very often they extend over long time periods; they are not susceptible to the typical measurement errors of survey data; and, finally, they are free of charge. The case of the Italian Liste di Mobilita, an Active Labor Market Policy (ALPM) to handle collective redundancies, illustrates how much empirical labor economics can benefit from having access to this kind of data. The accessibility of administrative archives for scientific purposes is a critical issue, as the history of this scheme demonstrates

    Lay-screeners and Use of WHO Growth Standards Increase Case Finding of Hospitalized Malawian Children with Severe Acute Malnutrition

    Get PDF
    Objectives: Strategies to effectively identify and refer children with severe acute malnutrition (SAM) to Nutritional Rehabilitation units (NRU) can reduce morbidity and mortality
    • …
    corecore