444 research outputs found

    Wind Variability in BZ Camelopardalis

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    (Shortened) Sequences of spectra of the nova-like cataclysmic variable (CV) BZ Cam were acquired on 9 nights in 2005-2006 in order to study the time development of episodes of wind activity known to occur frequently in this star. We confirm past results that the P-Cygni absorption components of the lines mostly evolve from a higher expansion velocity to lower velocity as an episode progresses. We also commonly find blueshifted emission components in the Halpha line profile, whose velocities and durations strongly suggest that they are also due to the wind. We suggest that the progression from larger to smaller expansion velocities is due the higher velocity portions of a wind concentration moving beyond the edge of the continuum light of the disk first, leaving a net redward shift of the remaining absorption profile. We also derive a new orbital ephemeris for BZ Cam, using the radial velocity of the core of the HeI 5876AA line, finding P = 0.15353(4). Using this period the wind episodes in BZ Cam are found to be concentrated near inferior conjuction of the emission line source. This result confirms that the winds in nova-like CVs are often phase dependent, in spite of the puzzling implication that such winds lack axisymmetry. We argue that the radiation-driven wind in BZ Cam receives an initial boost by acting on gas that has been lifted above the disk by the interaction of the accretion stream with the disk, thereby imposing flickering time scales onto the wind events, as well as leading to an orbital modulation of the wind due to the non-axisymmetric nature of the stream/disk interaction.Comment: The Astronomical Journal, in pres

    New Pulsating Variable Discovered in the Constellation Andromeda

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    Enhanced Monitoring of White Collar Employees: Should Employers Be Required to Disclose?

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    This Comment presents a five part legal and economic analysis of enhanced monitoring of white collar employees. Section I defines the employment contract. Section II provides an overview of the legal issues raised by enhanced monitoring of white collar employees. Section III discusses the economics of enhanced monitoring. Section IV presents an analysis of the legal and economic effects of an employer\u27s enhanced monitoring of white collar employees. Finally, Section V describes and evaluates proposed federal legislation that would require employers to disclose the use of enhanced monitoring to employees

    Enhanced Monitoring of White Collar Employees: Should Employers Be Required to Disclose?

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    This Comment presents a five part legal and economic analysis of enhanced monitoring of white collar employees. Section I defines the employment contract. Section II provides an overview of the legal issues raised by enhanced monitoring of white collar employees. Section III discusses the economics of enhanced monitoring. Section IV presents an analysis of the legal and economic effects of an employer\u27s enhanced monitoring of white collar employees. Finally, Section V describes and evaluates proposed federal legislation that would require employers to disclose the use of enhanced monitoring to employees

    Effectiveness of Foliar Fungicides by Timing on Hybrid Corn in Iowa

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    Fungicide use on hybrid corn has increased considerably in the past three growing seasons primarily due to reports of higher yields, even in the absence of disease and higher corn prices. A number of fungicides are registered for use on corn. The objectives of this project were to 1) compare the efficacy of various products for management of foliar corn diseases, 2) assess the effect of timing of application of fungicides on foliar disease development, and 3) evaluate the yield response of hybrid corn to foliar fungicide application

    Orbit-resolved photometry and echelle spectroscopy of the cataclysmic variable ST LMi during a 2007 high state

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    We present high-resolution echelle spectra and contemporaneous photometry of the polar ST LMi during a high state in 2007 March. Emission lines at Hα, He I λ5876, and He I λ7065 show similar line profiles over orbital phase and have narrow and broad components. These profile changes with phase are very similar to those reported in earlier high-state studies of ST LMi. The radial velocity curves from double Gaussian fits to the line profiles are interpreted as two crossing curves, neither of which is coincident with the orbital motion of the secondary star. We attribute one component to infall motions near the white dwarf and the other to a gas streaming along magnetic field lines connecting the two stars

    Neuropsychological Assessment of HIV-Infected Populations in International Settings

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    Resource-limited regions of the world represent the areas most affected by the global HIV epidemic. Currently, there are insufficient data on the neurocognitive effects of HIV in these areas and neuropsychological studies that have been carried out thus far are marked by inconsistent methods, test batteries, and rating systems for levels of cognitive impairment. These differences in methods, along with genetic variability of both virus and host, differences in co-infections and other co-morbidities, differences in language and culture, and infrastructural deficiencies in many international settings create challenges to the assessment of neurocognitive functioning and interpretation of neuropsychological data. Identifying neurocognitive impairment directly attributable to HIV, exploring relationships between HIV-associated neurocognitive impairment, disease variables, and everyday functioning, evaluating differences in HIV-1 subtype associated neuropathology, and determining implications for treatment remain complicated and challenging goals. Endeavors to establish a more standardized approach to neurocognitive assessments across international studies in addition to accumulating appropriate normative data that will allow more accurate rating of neuropsychological test performance will be crucial to future efforts attempting to achieve these goals

    Comparison of Susceptible and Resistant Maize Hybrids to Colonization by Clavibacter michiganensis subsp. nebraskensis

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    Clavibacter michiganensis subsp. nebraskensis causes Goss’s bacterial wilt and blight on maize and is managed primarily with C. michiganensis subsp. nebraskensis-resistant hybrids. To understand the mechanisms of resistance to infection by C. michiganensissubsp. nebraskensis, leaves of a susceptible and a resistant maize hybrid at the V4 to V5 developmental stage were wound inoculated with the pathogen. Blight lesion length was monitored, C. michiganensis subsp. nebraskensis colonizing ability was determined, and structural changes were observed using microscopy. Bacterial colonization preceded lesion development that occurred 4 to 5 days postinoculation in both hybrids. Lesion expansion in the susceptible hybrid was associated with a faster rate of C. michiganensis subsp. nebraskensis spread and multiplication in the tissues. In the resistant hybrid, spread and multiplication was reduced (P \u3c 0.0001) and, at 16 days postinoculation, became imperceptible. Initially, C. michiganensis subsp. nebraskensis showed a preference for colonization of the metaxylem vessels in both hybrids. Spread from cell to cell was accomplished through disruption of cell walls, presumably from abundance of bacterial cells or enzymatic activity. Morphological responses of the resistant maize hybrid to infection by C. michiganensis subsp. nebraskensis were similar to those reported in maize inbred lines that were resistant to Stewart’s wilt caused by Pantoea stewartii. Resistance to C. michiganensis subsp. nebraskensis was associated with production of a dense matrix in the xylem that deformed and restricted movement of the bacterial cells

    Poster - Private Pete Fights Illiteracy at Fort Ontario: The Men in Charge

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    A poster created by history students from Morehead State University for display at Fort Ontario Historic Site in March of 2023.https://scholarworks.moreheadstate.edu/stu_1210th_fort_ontario/1097/thumbnail.jp
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