5,291 research outputs found

    Radiometric calibration and processing procedure for reflective bands on LANDSAT-4 protoflight Thematic Mapper

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    The radiometric subsystem of NASA's LANDSAT-4 Thematic Mapper (TM) sensor is described. Special emphasis is placed on the internal calibrator (IC) pulse shapes and timing cycle. The procedures for the absolute radiometric calibration of the TM channels with a 122-centimeter integrating sphere and the transfer of radiometric calibration from the channels to the IC are reviewed. The use of the IC to calibrate TM data in the ground processing system consists of pulse integration, pulse averaging, IC state identification, linear regression analysis, and histogram equalization. An overview of the SCROUNGE-era (before August 1983) method is presented. Procedural differences between SCROUNGE and the TIPS-era (after July 1983) and the implications of these differences are discussed

    Characterization of radiometric calibration of LANDSAT-4 TM reflective bands

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    Prelaunch and postlaunch internal calibrator, image, and background data is to characterize the radiometric performance of the LANDSAT-4 TM and to recommend improved procedures for radiometric calibration. All but two channels (band 2, channel 4; band 5, channel 3) behave normally. Gain changes relative to a postlaunch reference for channels within a band vary within 0.5 percent as a group. Instrument gain for channels in the cold focal plane oscillates. Noise in background and image data ranges from 0.5 to 1.7 counts. Average differences in forward and reverse image data indicate a need for separate calibration processing of forward and reverse scans. Precision is improved by increasing the pulse integration width from 31 to 41 minor frames, depending on the band

    Generation of eigenstates using the phase-estimation algorithm

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    The phase estimation algorithm is so named because it allows the estimation of the eigenvalues associated with an operator. However it has been proposed that the algorithm can also be used to generate eigenstates. Here we extend this proposal for small quantum systems, identifying the conditions under which the phase estimation algorithm can successfully generate eigenstates. We then propose an implementation scheme based on an ion trap quantum computer. This scheme allows us to illustrate two simple examples, one in which the algorithm effectively generates eigenstates, and one in which it does not.Comment: 5 pages, 3 Figures, RevTeX4 Introduction expanded, typos correcte

    Spectral line shape of resonant four-wave mixing induced by broad-bandwidth lasers

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    We present a theoretical and experimental study of the line shape of resonant four-wave mixing induced by broad-bandwidth laser radiation that revises the theory of Meacher, Smith, Ewart, and Cooper (MSEC) [Phys. Rev. A 46, 2718 (1992)]. We adopt the same method as MSEC but correct for an invalid integral used to average over the distribution of atomic velocities. The revised theory predicts a Voigt line shape composed of a homogeneous, Lorentzian component, defined by the collisional rate Γ, and an inhomogeneous, Doppler component, which is a squared Gaussian. The width of the inhomogeneous component is reduced by a factor of √2 compared to the simple Doppler width predicted by MSEC. In the limit of dominant Doppler broadening, the width of the homogeneous component is predicted to be 4Γ, whereas in the limit of dominant homogeneous broadening, the predicted width is 2Γ. An experimental measurement is reported of the line shape of the four-wave-mixing signal using a broad-bandwidth, "modeless", laser resonant with the Q1 (6) line of the A2 Σ - X2 Π(0,0) system of the hydroxyl radical. The measured widths of the Voigt components were found to be consistent with the predictions of the revised theory

    Solar Carbon Monoxide, Thermal Profiling, and the Abundances of C, O, and their Isotopes

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    A solar photospheric "thermal profiling" analysis is presented, exploiting the infrared rovibrational bands of carbon monoxide (CO) as observed with the McMath-Pierce Fourier transform spectrometer (FTS) at Kitt Peak, and from above the Earth's atmosphere by the Shuttle-borne ATMOS experiment. Visible continuum intensities and center-limb behavior constrained the temperature profile of the deep photosphere, while CO center-limb behavior defined the thermal structure at higher altitudes. The oxygen abundance was self consistently determined from weak CO absorptions. Our analysis was meant to complement recent studies based on 3-D convection models which, among other things, have revised the historical solar oxygen (and carbon) abundance downward by a factor of nearly two; although in fact our conclusions do not support such a revision. Based on various considerations, an oxygen abundance of 700+/-100 ppm (parts per million relative to hydrogen) is recommended; the large uncertainty reflects the model sensitivity of CO. New solar isotopic ratios also are reported for 13C, 17O, and 18O.Comment: 90 pages, 19 figures (some with parts "a", "b", etc.); to be published in the Astrophysical Journal Supplement

    Schneiderian first rank symptoms: Reconfirmation of high specificity for schizophrenia

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    The prevalence of Schneiderian first-rank symptoms (FRS) in 294 consecutive admissions to a research unit was evaluated with reference to their diagnostic distribution (SADS/RDC). Thirty-five of 58 patients with schizophrenia had FRS, as compared to nine of 190 patients with major depressive disorder. All patients with two or more FRS received a diagnosis of schizophrenia. In the absence of organic or toxic etiology, the specificity of FRS for schizophrenia was 95% and their predictive value was 90%. These findings indicate that FRS should be regarded as strongly suggestive of schizophrenia in the absence of an organic syndrome.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65636/1/j.1600-0447.1987.tb02807.x.pd

    Ethnic In-Group Favoritism Among Minority and Majority Groups: Testing the Self-Esteem Hypothesis Among Preadolescents

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    The self-esteem hypothesis in intergroup relations, as proposed by social identity theory (SIT), states that successful intergroup discrimination enhances momentary collective self-esteem. This hypothesis is a source of continuing controversy. Furthermore, although SIT is increasingly used to account for children’s group attitudes, few studies have examined the hypothesis among children. In addition, the hypothesis’s generality makes it important to study among children from different ethnic groups. The present study, conducted among Dutch and Turkish preadolescents, examined momentary collective self-feelings as a consequence of ethnic group evaluations. The results tended to support the self-esteem hypothesis. In-group favoritism was found to have a self-enhancing effect among participants high in ethnic identification. This result was found for ethnic majority (Dutch) and minority (Turkish) participants.

    Quantum Clock Synchronization Based on Shared Prior Entanglement

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    We demonstrate that two spatially separated parties (Alice and Bob) can utilize shared prior quantum entanglement, and classical communications, to establish a synchronized pair of atomic clocks. In contrast to classical synchronization schemes, the accuracy of our protocol is independent of Alice or Bob's knowledge of their relative locations or of the properties of the intervening medium.Comment: 4 page

    Pre-sorting and pen size effects on the stress responses at loading and unloading and transport losses in market weight pigs

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    Transport losses represent three challenges for the US swine industry and these are: 1) pig well-being, 2) increased rules and regulations, and 3) direct financial losses to producers and packers. Therefore; improving the well-being of pigs during transport and reducing the incidence of dead and non-ambulatory pigs is a priority for the US swine industry (NPB, 2007). Johnson et al. (2010) studied the effects of grow-finish pen size and manually pre-sorting pigs the day before loading on the stress responses at loading and unloading and transport losses in market weight pigs. The authors reported that pigs loaded from large pens (192 pigs/pen) that were pre-sorted from pen mates had 66% fewer dead and non-ambulatory pigs at the harvest facility compared to pigs loaded from small pens (32 pigs/pen) that were sorted from pen mates during loading. However, it is unclear if the reduction in transport losses was due to pen size and/or pre-sorting before marketing. Therefore, the objectives of the current two research trials were to 1) determine the effects of pre-sorting prior to loading on stress responses and transport losses at the harvest facility in the market weight pig; and 2) determine the effects of grow-finish pen size on stress responses and transport losses at the harvest facility in the market weight pig
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