2,552 research outputs found

    Airborne monitoring of crop canopy temperatures for irrigation scheduling and yield prediction

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    Airborne and ground measurements were made on April 1 and 29, 1976, over a USDA test site consisting mostly of wheat in various stages of water stress, but also including alfalfa and bare soil. These measurements were made to evaluate the feasibility of measuring crop temperatures from aircraft so that a parameter termed stress degree day, SDD, could be computed. Ground studies have shown that SDD is a valuable indicator of a crop's water needs, and that it can be related to irrigation scheduling and yield. The aircraft measurement program required predawn and afternoon flights coincident with minimum and maximum crop temperatures. Airborne measurements were made with an infrared line scanner and with color IR photography. The scanner data were registered, subtracted, and color-coded to yield pseudo-colored temperature-difference images. Pseudo-colored images reading directly in daily SDD increments were also produced. These maps enable a user to assess plant water status and thus determine irrigation needs and crop yield potentials

    Analysis of electromagnetic interference from power system processing and transmission components for Space Station Freedom

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    The goal of this research project was to analyze the potential effects of electromagnetic interference (EMI) originating from power system processing and transmission components for Space Station Freedom. The approach consists of four steps: (1) developing analytical tools (models and computer programs); (2) conducting parameterization (what if?) studies; (3) predicting the global space station EMI environment; and (4) providing a basis for modification of EMI standards

    Comparison of multispectral remote-sensing techniques for monitoring subsurface drain conditions

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    The following multispectral remote-sensing techniques were compared to determine the most suitable method for routinely monitoring agricultural subsurface drain conditions: airborne scanning, covering the visible through thermal-infrared (IR) portions of the spectrum; color-IR photography; and natural-color photography. Color-IR photography was determined to be the best approach, from the standpoint of both cost and information content. Aerial monitoring of drain conditions for early warning of tile malfunction appears practical. With careful selection of season and rain-induced soil-moisture conditions, extensive regional surveys are possible. Certain locations, such as the Imperial Valley, Calif., are precluded from regional monitoring because of year-round crop rotations and soil stratification conditions. Here, farms with similar crops could time local coverage for bare-field and saturated-soil conditions

    Resonances in rotationally inelastic scattering of OH(X2ΠX^2\Pi) with helium and neon

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    We present detailed calculations on resonances in rotationally and spin-orbit inelastic scattering of OH (X\,^2\Pi, j=3/2, F_1, f) radicals with He and Ne atoms. We calculate new \emph{ab initio} potential energy surfaces for OH-He, and the cross sections derived from these surfaces compare favorably with the recent crossed beam scattering experiment of Kirste \emph{et al.} [Phys. Rev. A \textbf{82}, 042717 (2010)]. We identify both shape and Feshbach resonances in the integral and differential state-to-state scattering cross sections, and we discuss the prospects for experimentally observing scattering resonances using Stark decelerated beams of OH radicals.Comment: 14 pages, 15 Figure

    Shared visiting in Equator city

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    In this paper we describe an infrastructure and prototype system for sharing of visiting experiences across multiple media. The prototype supports synchronous co-visiting by physical and digital visitors, with digital access via either the World Wide Web or 3-dimensional graphics

    Flows of people in villages and large centres in Bronze Age Italy through strontium and oxygen isotopes

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    This study investigates to what extent Bronze Age societies in Northern Italy were permeable accepting and integrating non-local individuals, as well as importing a wide range of raw materials, commodities, and ideas from networks spanning continental Europe and the Mediterranean. During the second millennium BC, the communities of Northern Italy engaged in a progressive stabilization of settlements, culminating in the large polities of the end of the Middle/beginning of the Late Bronze Age pivoted around large defended centres (the Terramare). Although a wide range of exotic archaeological materials indicates that the inhabitants of the Po plain increasingly took part in the networks of Continental European and the Eastern Mediterranean, we should not overlook the fact that the dynamics of interaction were also extremely active on local and regional levels. Mobility patterns have been explored for three key-sites, spanning the Early to Late Bronze Age (1900–1100 BC), namely Sant’Eurosia, Casinalbo and Fondo Paviani, through strontium and oxygen isotope analysis on a large sample size (more than 100 individuals). The results, integrated with osteological and archaeological data, document for the first time in this area that movements of people occurred mostly within a territorial radius of 50 km, but also that larger nodes in the settlement system (such as Fondo Paviani) included individuals from more distant areas. This suggests that, from a demographic perspective, the process towards a more complex socio-political system in Bronze Age Northern Italy was triggered by a largely, but not completely, internal process, stemming from the dynamics of intra-polity networks and local/regional power relationships

    Explorations in anatomy: the remains from Royal London Hospital

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    This paper considers the faunal remains from recent excavations at the Royal London Hospital. The remains date to the beginning of the 19th century and offer an insight into the life of the hospital's patients and practices of the attached medical school. Many of the animal remains consist of partially dissected skeletons, including the unique finds of Hermann's tortoise (Testudo hermanni) and Cercopithecus monkey. The hospital diet and developments in comparative anatomy are discussed by integrating the results with documentary research. They show that zooarchaeological study of later post-medieval material can significantly enhance our understanding of the exploitation of animals in this perio

    Analytic Inversion of Emission Lines of Arbitrary Optical Depth for the Structure of Supernova Ejecta

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    We derive a method for inverting emission line profiles formed in supernova ejecta. The derivation assumes spherical symmetry and homologous expansion (i.e., v(r)rv(r) \propto r), is analytic, and even takes account of occultation by a pseudo-photosphere. Previous inversion methods have been developed which are restricted to optically thin lines, but the particular case of homologous expansion permits an analytic result for lines of {\it arbitrary} optical depth. In fact, we show that the quantity that is generically retrieved is the run of line intensity IλI_\lambda with radius in the ejecta. This result is quite general, and so could be applied to resonance lines, recombination lines, etc. As a specific example, we show how to derive the run of (Sobolev) optical depth τλ\tau_\lambda with radius in the case of a pure resonance scattering emission line.Comment: 6 pages, no figures, to appear in Astrophysical Journal Letters, requires aaspp4.sty to late

    A Comparative Study of the Absolute-Magnitude Distributions of Supernovae

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    The Asiago Supernova Catalog is used to carry out a comparative study of supernova absolute-magnitude distributions. An overview of the absolute magnitudes of the supernovae in the current observational sample is presented, and the evidence for subluminous and overluminous events is examined. The fraction of supernovae that are underluminous (M_B > -15) appears to be higher (perhaps much higher) than one fifth but it remains very uncertain. The fraction that are overluminous (M_B < -20) is lower (probably much lower) than 0.01. The absolute-magnitude distributions for each supernova type, restricted to events within 1 Gpc, are compared. Although these distributions are affected by observational bias in favor of the more luminous events, they are useful for comparative studies. We find mean absolute blue magnitudes (for H_0=60) of -19.46 for normal Type Ia supernovae (SNe Ia), -18.04 for SNe Ibc, -17.61 and -20.26 for normal and bright SNe Ibc considered separately, -18.03 for SNe II-L, -17.56 and -19.27 for normal and bright SNe II-L considered separately, -17.00 for SNe II-P, and -19.15 for SNe IIn.Comment: 27 pages, accepted for publication by the Astronomical Journal (Feb. 2002
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