22,336 research outputs found

    High-resolution observation of the Venus dayglow spectrum 1250-1430 angstroms

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    The spectrum of the dayglow of Venus between 1250 and 1430 A was measured in high resolution with the International Ultraviolet Explorer. Seven exposures which were made with the short wavelength camera in the high dispersion mode using the large aperture were combined to give a total exposure time of 309 min. The atomic oxygen lines at 1302.2, 1304.9, 1306.0, and 1355.6 A are present. In addition, the (14,3) and (14,4) bands of the carbon monoxide fourth positive system at 1317 and 1354 A respectively are identified. These bands are compared with synthetic spectra, showing the excitation mechanism to be fluorescent scattering of solar Lyman alpha radiation

    Seasonal observation of Mars

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    The International Ultraviolet Explorer detected the Hartley bands of ozone in the spectrum of Mars. Seasonal observations show a variation in the north consistent with the measurement of Mariner 9. Observations during Martian late fall in the south were also made

    The Collider Phenomenology of Technihadrons in the Technicolor Straw Man Model

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    We discuss the phenomenology of the lightest SU(3)_C singlet and non-singlet technihadrons in the Straw Man Model of low-scale technicolor (TCSM). The technihadrons are assumed to be those arising in topcolor--assisted technicolor models in which topcolor is broken by technifermion condensates. We improve upon the description of the color--singlet sector presented in our earlier paper introducing the TCSM (hep-ph/9903369). These improvements are most important for subprocess energies well below the masses of the technirho and techniomega, and, therefore, apply especially to e+e- colliders such as LEP and a low--energy linear collider. In the color--octet sector, we consider mixing of the gluon, the coloron V_8 from topcolor breaking, and four isosinglet color--octet technirho mesons. We assume, as expected in walking technicolor, that these technirhos decay into qbar-q, gg, and g-technipion final states, but not into technipion pairs. All the TCSM production and decay processes discussed here are included in the event generator Pythia. We present several simulations appropriate for the Tevatron Collider, and suggest benchmark model lines for further experimental investigation.Comment: 42 pages, 7 figure

    Observations of the Io plasma torus

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    The short wavelength spectrography on the IUE satellite was used to obtain spectra of the plasma torus near the orbit of Io about Jupiter. Three exposures of about 8 hours each taken in March and May 1979 show emission features due to SII, SIII, and OIII. The absence of features at other wavelengths permits upper limits to be other species in the torus

    Observations of polar aurora on Jupiter

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    North-south spatial maps of Jupiter were obtained with the SWP camera in IUE observations of 10 December 1978, 19 May 1979, and 7 June 1979. Bright auroral emissions were detected from the north and south polar regions at H Ly alpha (1216 A) and in the H2 Lyman bands (1250-1608 A) on 19 May 1979; yet no enhanced polar emission was detected on the other days. The relationship between the IUE observing geometry and the geometry of the Jovian magnetosphere is discussed

    Direct radiative capture of p-wave neutrons

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    The neutron direct radiative capture (DRC) process is investigated, highlighting the role of incident p-wave neutrons. A set of calculations is shown for the 12-C(n,gamma) process at incoming neutron energies up to 500 keV, a crucial region for astrophysics. The cross section for neutron capture leading to loosely bound s, p and d orbits of 13-C is well reproduced by the DRC model demonstrating the feasibility of using this reaction channel to study the properties of nuclear wave functions on and outside the nuclear surface. A sensitivity analysis of the results on the neutron-nucleus interaction is performed for incident s- as well as p-waves. It turned out that the DRC cross section for p-wave neutrons is insensitive to this interaction, contrary to the case of incident s-wave neutrons. PACS number(s): 25.40Lw,21.10Gv,23.40.HcComment: 16 pages, REVTeX file, PostScript file, .dvi fil

    Stem Cells and DNA Damage: Persist or Perish?

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    Stem cells repopulate tissues after injury while also renewing themselves, but this makes them vulnerable to genotoxic damage. Mohrin et al. (2010) and Milyavsky et al. (2010) now show that mouse and human hematopoietic stem cells make opposing decisions about whether to die or to persist in response to DNA damage

    The interaction of brain regions during visual search processing as revealed by transcranial magnetic stimulation

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    Although it has long been known that right posterior parietal cortex (PPC) has a role in certain visual search tasks, and human motion area V5 is involved in processing tasks requiring attention to motion, little is known about how these areas may interact during the processing of a task requiring the speciality of each. Using transcranial magnetic stimulation (TMS), this study first established the specialization of each area in the form of a double dissociation; TMS to right PPC disrupted processing of a color/form conjunction and TMS to V5 disrupted processing of a motion/form conjunction. The key finding of this study is, however, if TMS is used to disrupt processing of V5 at its critical time of activation during the motion/form conjunction task, concurrent disruption of right PPC now has a significant effect, where TMS at PPC alone does not. Our findings challenge the conventional interpretation of the role of right PPC in conjunction search and spatial attention

    When the Senate plays politics with Supreme Court vacancies this hurts the public’s perceptions of the Court

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    The recent US Senate confirmation of Judge Ketanji Brown Jackson for the Supreme Court has shown how politicized such hearings have become. But how do these more contentious hearings influence how the American public thinks about the Supreme Court itself? In new survey research, Miles T. Armaly and Elizabeth A. Lane examine reactions to the US Senate’s approach to filling Justice Ruth Bader Ginsburg’s Supreme Court seat. They find that respondents who were told about the politicization of a past vacancy were less likely to express support for the Supreme Court and to favor reforms which would reduce its power
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