995 research outputs found
An Ultraviolet Fe II Image of SN 1885 in M31
Ultraviolet imaging of the remnant of Supernova 1885 in M31 with the Hubble
Space Telescope using the F255W filter on the WFPC2 reveals a dark spot of Fe
II absorption at the remnant's known position in the bulge of M31. The diameter
of the absorbing spot is 0"55 +- 0"15, slightly smaller than, but consistent
with, the 0"70 +- 0"05 diameter measured in the higher quality WFPC2 Ca II
absorption image previously reported by us. The measured ratio of flux inside
to outside SNR 1885 in the Fe II image is 0.24 +- 0.17, consistent with the
ratio 0.33 +- 0.04 expected on the basis of a model fit to the previously
obtained near-UV FOS spectrum. The observed depth of Fe II absorption suggests
that Fe II is fully saturated, with an iron mass in the range M_Fe = 0.1-1.0
Msun. Besides Fe, ion species Mg I, Mg II, and Mn I probably make some
contribution to the absorption from the SN 1885 remnant in the F255W image.Comment: 7 pages, including 2 embedded PostScript figures, emulateapj.sty,
submitted to Ap
Directional detection of Dark Matter
Among the many experimental techniques available, those providing directional
information have the potential of yielding an unambiguous observation of WIMPs
even in the presence of insidious backgrounds. A measurement of the
distribution of arrival direction of WIMPs can also discriminate between
Galactic Dark Matter halo models. In this article, I will discuss the
motivation for directional detectors and review the experimental techniques
used by the various experiments. I will then describe one of them, the DMTPC
detector, in more detail.Comment: 17 pages, 11 postscript figures, mini-review submitted to Modern
Physics Letters A (MPLA). Submitted to Modern Physics Letters A (MPLA
Parametrized post-Newtonian virial theorem
Using the parametrized post-Newtonian equations of hydrodynamics, we derive
the tensor form of the parametrized post-Newtonian virial theorem.Comment: 10 pages, submitted to CQ
Galactic Nonlinear Dynamic Model
We develop a model for spiral galaxies based on a nonlinear realization of
the Newtonian dynamics starting from the momentum and mass conservations in the
phase space. The radial solution exhibits a rotation curve in qualitative
accordance with the observational data.Comment: 6 pages, 1 figure. Talk given in the 7th Alexander Friedmann
International Seminar, June 29 to July 5, 2008, Joao Pessoa, PB, Brazi
Linguistics
Contains reports on one research project.National Science Foundation (Grant GP-2495)National Institutes of Health (Grant MH-04737-04)U. S. Air Force (Electronics Systems Division) under Contract AF 19(628)-2487National Aeronautics and Space Administration (Grant NsG-496
Student Information Use and Decision-Making in Innovation Competitions
At a large university in the Midwestern United States, librarians work closely with an undergraduate agricultural innovation competition. Librarians serve as entrepreneurial information guides, providing business information instruction and consulting with student groups to mentor them through the innovation process. The competition, with a winning prize of $20,000, focuses on developing new products from soybeans to foster environmental stewardship and reduce reliance on petroleum. Competitions are a form of experiential learning, allowing students to fully experience the product design process and practice making evidence-based decisions. In order to progress through this competition, the students’ inventions must be shown to have environmental benefits, technical benefits, feasibility, and novelty. Early stages of the competition require students to investigate and report on the marketability and patentability of their inventions. As a part of this process, students meet with a business librarian and a patent librarian. The business librarian consults with the students on how to conduct market research, and discusses concepts such as ideation, evidence-based decision-making, performing a market analysis, and determining a target market for their products. The patent librarian consults with the students on intellectual property and the United States patent system, focusing on basic patent searching tools and methods and discussing the concept of “novelty” in the area of new inventions.
In 2018, the authors conducted focus groups of students who had competed in that year’s competition, to learn how students find and use information in a competition setting and to determine the extent of the impact library support had on the students’ use of information. The groups included students at all points in their undergraduate careers, and some students who had participated in the competition multiple times. This presentation will present the results of the focus groups and how they will inform continued assessment in future iterations of the competition. Themes explored will include information resources, such as market research databases, search engines, and patent search tools; decision-making; the use of information in the design process; librarians as consultants; and future improvements
Neutrino Constraints on the Dark Matter Total Annihilation Cross Section
In the indirect detection of dark matter through its annihilation products,
the signals depend on the square of the dark matter density, making precise
knowledge of the distribution of dark matter in the Universe critical for
robust predictions. Many studies have focused on regions where the dark matter
density is greatest, e.g., the Galactic Center, as well as on the cosmic signal
arising from all halos in the Universe. We focus on the signal arising from the
whole Milky Way halo; this is less sensitive to uncertainties in the dark
matter distribution, and especially for flatter profiles, this halo signal is
larger than the cosmic signal. We illustrate this by considering a dark matter
model in which the principal annihilation products are neutrinos. Since
neutrinos are the least detectable Standard Model particles, a limit on their
flux conservatively bounds the dark matter total self-annihilation cross
section from above. By using the Milky Way halo signal, we show that previous
constraints using the cosmic signal can be improved on by 1-2 orders of
magnitude; dedicated experimental analyses should be able to improve both by an
additional 1-2 orders of magnitude.Comment: 8 pages, 4 figures; Matches version published in Phys. Rev.
Student Information Use and Decision-Making in Innovation Competitions and the Impact of Librarian Interventions
At a large Midwestern university, librarians work closely with an annual undergraduate agricultural innovation competition to guide students through the process of conducting market research and assessing patentability. In 2018, the authors conducted an exploratory study using focus groups of students who had participated in that year’s competition in order to learn how students find and use information in a competition setting, to evaluate the impact of library support on the students’ success, and inform further assessment activities. Results showed that students used information from the library and from their own research, notably seeking out first-hand expertise, to practice evidence-based decision-making
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