1,821 research outputs found

    Pilot education and safety awareness programs

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    Guidelines necessary for the implementation of safety awareness programs for commuter airlines are discussed. A safety office can be viewed as fulfilling either an education and training function or a quality assurance function. Issues such as management structure, motivation, and cost limitations are discussed

    Unpulsed UBV Optical Emission from the Crab Pulsar

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    Based on observations of the Crab pulsar using the TRIFFID high speed imaging photometer in the UBV bands using the Special Astrophysical Observatory's 6m telescope in the Russian Caucasus, we report the detection of pronounced emission during the so-called `off' phase of emission. Following de-extinction, this unpulsed component of emission is shown to be consistent with a power law with an exponent of alpha = -0.60 +/- 0.37, the uncertainty being dominated by the error associated with the independent CCD photometry used to reference the TRIFFID data. This suggests a steeper power law form than that reported elsewhere in the literature for the total integrated spectrum, which is essentially flat with alpha ~ 0.1, although the difference in this case is only significant at the ~ 2 sigma level. Deeper reference integrated and TRIFFID phase-resolved photometry in these bands in conjunction with further observations in the UV and R region would constrain this fit further.Comment: 26 pages, 2 figures, uses aasms4.sty, accepted for publication in the Astrophysical Journa

    A Dialectical Basis for Software Development Tool Building

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    We identify typical problems in the interactions of people with current software-based systems. In particular we observe the need to expend significant on-going effort to adapt these systems to reflect changes in the world about them, the need for people to adapt their working practices to fit in with these systems, and the inflexibility of these systems when faced with unusual circumstances or the need for change. We believe that these problems follow, at least in part, from these systems being developed and evolved using mechanisms each based on one Inquiry System only. This basis leads to assumptions being embedded in the mechanisms’ analysis outputs, and in system designs and implementations. We suggest that the problems noted may be mitigated by the use of a dialectical approach to Inquiry System selection for software development, based on the work of Hegel, which places in opposition different models of a situation based on different Inquiry Systems. We claim that such a mechanism has the potential to make explicit some of the assumptions which would otherwise be embedded implicitly in the delivered system without being questioned. We outline a research programme intended to test this hypothesis, and suggest other research directions

    Implications of the Optical Observations of Neutron Stars

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    We show that observations of pulsars with pulsed optical emission indicate that the peak flux scales according to the magnetic field strength at the light cylinder. The derived relationships indicate that the emission mechanism is common across all of the observed pulsars with periods ranging from 33ms to 385 ms and ages of 1000-300,000 years. It is noted that similar trends exist for Îł\gamma ray pulsars. Furthermore the model proposed by Pacini (1971) and developed by Pacini and Salvati (1983,1987) still has validity and gives an adequate explanation of the optical phenomena.Comment: 23 pages, 6 figures, accepted for publication in the Astrophysical Journa

    The inheritance of color and horns in Blue-gray cattle II

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    This bulletin is a sequel to Research Bulletin No. 30 published in 1916. It contains information and a discussion concerning the progeny from the original stock subsequent to that date. The work of the previous investigators, their results and the conclusions drawn therefrom, are retabulated without details. Additional data are added showing that the recessive whites obtained from the F2 breed true. The nature of the roan in the Shorthorn is considered. While it is recognized that Wright\u27s criticism of the hypothesis used (Wentworth\u27s) rendered it improbable, yet the fact that two whites when mated to self-colored bulls threw self-colored calves, seems to disprove the hypothesis that roan is the simple heterozygote between self-pigmented and white. Accordingly no conclusions are drawn with respect to roaning. The relation of these whites with dark points to the similarly marked Wild White Park Cattle of Great Britain is discussed, and the conclusion is drawn that they are of a different genetic composition, the former being recessive and the latter dominant to most colors. It seems probable that the only coat color difference between these whites with dark points and the white Shorthorn lies in the degree of pigmentation in the points. The presence of pigment in the ears shows dominance over the almost complete lack of it. A white with red points was obtained, as demanded by Lloyd Jones\u27 and Evvard\u27s theory. Matings of the white with dark points to the almost white Ayrshire reveal that there is no genetic similarity between the two types of white. Data were obtained from these matings, but not in a quantity sufficient to advance or prove any hypothesis. Detailed tables and descriptions of the new individuals are presented

    Malignant phyllodes tumor in a patient with hereditary retinoblastoma: a case report and literature review

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    Patients with hereditary retinoblastoma are at increased risk for second malignancies, most notably sarcomas, particularly after treatment with radiation. Malignant phyllodes tumor is a rare secondary malignancy in these patients. We present a review of the literature and report of a patient with hereditary retinoblastoma who developed two secondary malignancies, including malignant phyllodes tumor. The patient’s phyllodes tumor presented as a palpable breast mass with suspicious findings on mammogram and ultrasound. The mass was shown to be at least a borderline phyllodes tumor via sonographic percutaneous biopsy and confirmed malignant phyllodes tumor on final surgical excision

    Estimations of electron-positron pair production at high-intensity laser interaction with high-Z targets

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    Electron-positron pairs' generation occuring in the interaction of 101810^{18}-102010^{20}~W/cm2^2 laser radiation with high-Z targets are examined. Computational results are presented for the pair production and the positron yield from the target with allowance for the contribution of pair production processes due to electrons and bremsstrahlung photons. Monte-Carlo simulations using the PRIZMA code confirm the estimates obtained. The possible positron yield from high-Z targets irradiated by picosecond lasers of power 10210^2-10310^3~TW is estimated to be 10910^9-101110^{11}

    Seasonal cues induce phenotypic plasticity of Drosophila suzukii to enhance winter survival

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    Additional file 7: Table S6. Table of differentially expressed genes in bodies of winter morphs of D. suzukii relative to those of summer morphs. Fold change represents the ratio of expression levels of winter to summer morphs

    First impressions and perceived roles: Palestinian perceptions on foreign aid

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    This paper summarizes some results of a wider research on foreign aid that was conducted in the West Bank and Gaza Strip in 2010. It seeks to describe the impressions and feelings of Palestinian aid beneficiaries as well as the roles and functions they attached to foreign aid. To capture and measure local perceptions on Western assistance a series of individual in depth interviews and few focus group interviews were conducted in the Palestinian territories. The interview transcripts were processed by content analysis. As research results show — from the perspective of aid beneficiaries — foreign aid is more related to human dignity than to any economic development. All this implies that frustration with the ongoing Israeli-Palestinian conflict inevitably embraces the donor policies and practices too

    Strain-Based Analysis for Geometrically Nonlinear Beams: A Modal Approach

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97066/1/AIAA2012-1713.pd
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