6,246 research outputs found

    LANDSAT Digital Data Base Preparation for the Pennsylvania Defoliation Application Pilot Test

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    A LANDSAT digital mosaic data base for the State of Pennsylvania was prepared for use in the development of an automated system to annually estimate the extent and severity of Gypsy Moth defoliation of hardward forests. The techniques for detecting the defoliation and development of a geographic information system (GIS) to assess damage is being developed jointly by NASA/Goddard Space Flight Center and Pennsylvania State University using the JPL prepared mosaic base. The JPL processing involved the use of ground control points from the Master Data Processor for planimetric control, resampling of the LANDSAT data to 57 x 57 meter pixels, realignment to north, and reprojection to the Universal Transverse Mercator (UTM) projection in UTM zones 17 and 18. The completed mosaic for each UTM zone was subdivided into 1 degree of latitude by 2 degrees of longitude quadrangles for easy data handling. Consideration is given to the issues of mapping standards, sensor and spacecraft platform characteristics, and their implication to geographic information systems operation. Methods for obtaining measures of accuracy for LANDSAT mosaics are reviewed

    NICMOS Observations of Low-Redshift Quasar Host Galaxies

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    We have obtained Near-Infrared Camera and Multi-Object Spectrometer images of 16 radio quiet quasars observed as part of a project to investigate the ``luminosity/host-mass limit.'' The limit results were presented in McLeod, Rieke, & Storrie-Lombardi (1999). In this paper, we present the images themselves, along with 1- and 2-dimensional analyses of the host galaxy properties. We find that our model-independent 1D technique is reliable for use on ground-based data at low redshifts; that many radio-quiet quasars live in deVaucouleurs-law hosts, although some of the techniques used to determine host type are questionable; that complex structure is found in many of the hosts, but that there are some hosts that are very smooth and symmetric; and that the nuclei radiate at ~2-20% of the Eddington rate based on the assumption that all galaxies have central black holes with a constant mass fraction of 0.6%. Despite targeting hard-to-resolve hosts, we have failed to find any that imply super-Eddington accretion rates.Comment: To appear in ApJ, 28 pages including degraded figures. Download the paper with full-resolutio figures from http://www.astro.wellesley.edu/kmcleod/mm.p

    Whiskerless Schottky diode

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    A Schottky diode for millimeter and submillimeter wave applications is comprised of a multi-layered structure including active layers of gallium arsenide on a semi-insulating gallium arsenide substrate with first and second insulating layers of silicon dioxide on the active layers of gallium arsenide. An ohmic contact pad lays on the silicon dioxide layers. An anode is formed in a window which is in and through the silicon dioxide layers. An elongated contact finger extends from the pad to the anode and a trench, preferably a transverse channel or trench of predetermined width, is formed in the active layers of the diode structure under the contact finger. The channel extends through the active layers to or substantially to the interface of the semi-insulating gallium arsenide substrate and the adjacent gallium arsenide layer which constitutes a buffer layer. Such a structure minimizes the effect of the major source of shunt capacitance by interrupting the current path between the conductive layers beneath the anode contact pad and the ohmic contact. Other embodiments of the diode may substitute various insulating or semi-insulating materials for the silicon dioxide, various semi-conductors for the active layers of gallium arsenide, and other materials for the substrate, which may be insulating or semi-insulating

    An exploration into the client at the heart of therapy : a qualitative perspective

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    Over 50 years ago Eysenck challenged the existing base of research into psychotherapy. Since that time, a large number of investigations have been conducted to verify the efficacy of therapy. Recently however, an increasing number of studies have cast new doubts on this research base. Instead of therapy being a function of the therapist, it is now becoming ever more apparent that the client plays a prime role in the therapeutic process. The qualitative studies presented in this paper provide some examples of research that demonstrates that clients are actively involved in their therapy, even making counselling work despite their counsellor. These studies suggest that clients may not experience therapy as beneficially as traditional outcome studies indicate. This raises a new challenge to researchers to more fully explore the client's experience of therapy, a challenge to which qualitative methods of inquiry would appear well suited

    Algorithms for Linear Time Series Analysis: With R Package

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    Our ltsa package implements the Durbin-Levinson and Trench algorithms and provides a general approach to the problems of fitting, forecasting and simulating linear time series models as well as fitting regression models with linear time series errors. For computational efficiency both algorithms are implemented in C and interfaced to R. Examples are given which illustrate the efficiency and accuracy of the algorithms. We provide a second package FGN which illustrates the use of the ltsa package with fractional Gaussian noise (FGN). It is hoped that the ltsa will provide a base for further time series software.

    Efficacy of Vitaflo 280 to control soil- and seed-borne diseases of pea and lentil, and compatibility with rhizobium inoculants

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    Non-Peer ReviewedLentil (Lens culinaris Medikus) and pea (Pisum sativum L.) have the ability to fix dinitrogen (N2) from the atmosphere. Rhizobium inoculants are applied to the seed to ensure effective N2 fixation. In addition, fungicidal seed treatments are recommended to control extremely aggressive diseases such as Ascochyta, Botrytis, Fusarium, and Rhizoctonia seedling blight. To determine the efficacy of Vitaflo 280 to control seedling blight of pea and lentil caused by Botrytis cinerea, Mycosphaerella pinodes (Ascochyta blight), Rhizoctonia solani and Fusarium spp. experiments were established at several locations and years in western Canada. To determine the effect of Crown, Allegiance FL, Vitaflo 280, and Apron Maxx on the ability of Rhizobium inoculants to nodulate and fix N2 from the atmosphere experiments were established at two locations in Saskatchewan in 2002. Vitaflo 280 at the recommended rates effectively controls seedling blight of lentil caused by seed-borne Botrytis cinerea and soil-borne Fusarium spp and Rhizoctonia solani. Vitaflo 280 at the recommended rates effectively controls seedling blight of pea caused by seed-borne Mycosphaerella pinodes and soil-borne Fusarium spp and Rhizoctonia solani. In addition, Allegiance FL, Crown, Vitaflo 280, and Apron Maxx at the recommended rates have no effect on visual nodulation or the ability of the Rhizobium to fix N2 from the atmosphere

    Algorithms for Linear Time Series Analysis: With R Package

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    Our ltsa package implements the Durbin-Levinson and Trench algorithms and provides a general approach to the problems of fitting, forecasting and simulating linear time series models as well as fitting regression models with linear time series errors. For computational efficiency both algorithms are implemented in C and interfaced to R. Examples are given which illustrate the efficiency and accuracy of the algorithms. We provide a second package FGN which illustrates the use of the ltsa package with fractional Gaussian noise (FGN). It is hoped that the ltsa will provide a base for further time series software
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