2,372 research outputs found
Extended range harmonic filter
Two types of filters, leaky-wall and open-guide, are combined into single component. Combination gives 10 db or greater additional attenuation to fourth and higher harmonics, at expense of increasing loss of fundamental frequency by perhaps 0.05 to 0.08 db. Filter is applicable to all high power microwave transmitters, but is especially desirable for satellite transmitters
Corporations: An Untapped Resource for Higher Education Administrators who Seek to Enhance Student Learning
Higher education currently has a strict focus on the personal, intellectual, and social development of students. However, little attention is given to student development after college, particularly, to students who enter the real world and choose to work for a corporation. Colleges and corporations need to work together to assist students during the transition out of college and into the corporate workplace. Internships provide one means of cooperation between the two parties. This paper will explore how colleges and corporations can enhance student development and better prepare students for a post-collegiate corporate career
Shuttle/spacelab MMAP/electromagnetic environment experiment phase B definition study
Progress made during the first five months of the Phase B definition study for the MMAP/Electromagnetic Environment Experiment (EEE) was described. An antenna/receiver assembly has been defined and sized for stowing in a three pallet bay area in the shuttle. Six scanning modes for the assembly are analyzed and footprints for various antenna sizes are plotted. Mission profiles have been outlined for a 400 km height, 57 deg inclination angle, circular orbit. Viewing time over 7 geographical areas are listed. Shuttle interfaces have been studied to determine what configuration the antenna assembly must have to be shared with other experiments of the Microwave Multi-Applications Payload (MMAP) and to be stowed in the shuttle bay. Other results reported include a frequency plan, a proposed antenna subsystem design, a proposed receiver design, preliminary outlines of the experiment controls and an analysis of on-board and ground data processing schemes
Debye mass and heavy quark potential in a PNJL quark plasma
We calculate the Debye mass for the screening of the heavy quark potential in
a plasma of massless quarks coupled to the temporal gluon background governed
by the Polyakov loop potential within the PNJL model in RPA approximation. We
give a physical motivation for a recent phenomenological fit of lattice data by
applying the calculated Debye mass with its suppression in the confined phase
due to the Polyakov-loop to a description of the temperature dependence of the
singlet free energy for QCD with a heavy quark pair at infinite separation. We
compare the result to lattice data.Comment: 6 pages, 1 figure, contribution to Proceedings of the 6th
International Conference on "Critical Point and Onset of Deconfinement", to
appear in Phys. At. Nucl., vol. 7
A New 5 Flavour NLO Analysis and Parametrizations of Parton Distributions of the Real Photon
New, radiatively generated, NLO quark (u,d,s,c,b) and gluon densities in a
real, unpolarized photon are presented. We perform three global fits, based on
the NLO DGLAP evolution equations for Q^2>1 GeV^2, to all the available
structure function F_2^gamma(x,Q^2) data. As in our previous LO analysis we
utilize two theoretical approaches. Two models, denoted as FFNS_{CJK}1 & 2 NLO,
adopt the so-called Fixed Flavour-Number Scheme for calculation of the
heavy-quark contributions to F_2^gamma(x,Q^2), the CJK NLO model applies the
ACOT(chi) scheme. We examine the results of our fits by a comparison with the
LEP data for the Q^2 dependence of the F_2^gamma, averaged over various
x-regions, and the F_2,c^gamma. Grid parametrizations of the parton densities
for all fits are provided.Comment: 49 pages, 27 postscript figures; FORTRAN programs available at
http://www.fuw.edu.pl/~pjank/param.htm
Hormone Therapy for Postmenopausal Women with Urinary Incontinence
Postmenopausal women should not receive oral hormone therapy for treatment of urinary incontinence. Hormone therapy is associated with worsening urinary incontinence in postmenopausal women who are incontinent at baseline (Strength of Recommendation [SOR]: A, based on a systematic review) and is associated with an increased risk of developing urinary incontinence in those who are continent at baseline (SOR: A, based on two large randomized controlled trials [RCTs])
On the Tapping Mode Measurement for Youngâs Modulus of Nanocrystalline Metal Coatings
Youngâs modulus of nanocrystalline metal coatings is measured using the oscillating, that is, tapping, mode of a cantilever with a diamond tip. The resonant frequency of the cantilever changes when the diamond tip comes in contact with a sample surface. A Hertz-contact-based model is further developed using higher-order terms in a Taylor series expansion to determine a relationship between the reduced elastic modulus and the shift in the resonant frequency of the cantilever during elastic contact between the diamond tip and sample surface. The tapping mode technique can be used to accurately determine Youngâs modulus that corresponds with the crystalline orientation of the sample surface as demonstrated for nanocrystalline nickel, vanadium, and tantalum coatings
Mrgprd Enhances Excitability in Specific Populations of Cutaneous Murine Polymodal Nociceptors
The Mas-related G protein-coupled receptor D (Mrgprd) is selectively expressed in nonpeptidergic nociceptors that innervate the outer layers of mammalian skin. The function of Mrgprd in nociceptive neurons and the physiologically relevant somatosensory stimuli that activate Mrgprd^-expressing (Mrgprd^+) neurons are currently unknown. To address these issues, we studied three Mrgprd knock-in mouse lines using an ex vivo somatosensory preparation to examine the role of the Mrgprd receptor and Mrgprd+ afferents in cutaneous somatosensation. In mouse hairy skin, Mrgprd, as marked by expression of green fluorescent protein reporters, was expressed predominantly in the population of nonpeptidergic, TRPV1-negative, C-polymodal nociceptors. In mice lacking Mrgprd, this population of nociceptors exhibited decreased sensitivity to cold, heat, and mechanical stimuli. Additionally, in vitro patch-clamp studies were performed on cultured dorsal root ganglion neurons from Mrgprd^(â/â) and Mrgprd^(+/â) mice. These studies revealed a higher rheobase in neurons from Mrgprd^(â/â) mice than from Mrgprd^(+/â) mice. Furthermore, the application of the Mrgprd ligand ÎČ-alanine significantly reduced the rheobase and increased the firing rate in neurons from Mrgprd^(+/â) mice but was without effect in neurons from Mrgprd^(â/â) mice. Our results demonstrate that Mrgprd influences the excitability of polymodal nonpeptidergic nociceptors to mechanical and thermal stimuli
The appearance potency of gay and straight menâs websites
Gay men's greater body dissatisfaction compared to straight men has been explained as a result of gay menâs more 'appearance potent' subculture. This study aimed to critically appraise this explanation by assessing images of men and women for their physical characteristics and objectification across 8 popular gay and straight men's dating and porn websites. 1,415 images of men and 715 images of women across the websiteâs main pages were coded. Results showed that the gay men's websites featured more images of men that were appearance-ideal, nude, and sexualized in comparison to the straight men's websites. With the converse true for straight menâs websites. These results highlight the continuing need to develop and provide interventions that critique the appearance potency of popular media, particularly so for gay men
Quiver Diagonalization and Open BPS States
We show that motivic DonaldsonâThomas invariants of a symmetric quiver Q, captured by the generating function P Q, can be encoded in another quiver Q (â) of (almost always) infinite size, whose only arrows are loops, and whose generating function P Q  (â) is equal to P Q upon appropriate identification of generating parameters. Consequences of this statement include a generalization of the proof of integrality of DonaldsonâThomas and LabastidaâMariñoâOoguriâVafa invariants that count open BPS states, as well as expressing motivic DonaldsonâThomas invariants of an arbitrary symmetric quiver in terms of invariants of m-loop quivers. In particular, this means that the already known combinatorial interpretation of invariants of m-loop quivers extends to arbitrary symmetric quivers
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