942 research outputs found
A survey of numerical models for wind prediction
A literature review is presented of the work done in the numerical modeling of wind flows. Pertinent computational techniques are described, as well as the necessary assumptions used to simplify the governing equations. A steady state model is outlined, based on the data obtained at the Deep Space Communications complex at Goldstone, California
Thermal analysis of antenna backup structure. Part 1. Methodology development
An analytic method was devised to predict the temperature distribution in typical antenna structural back-up members. The results are in agreement with those obtained by a numerical shooting method. The analytic method shows potential in simplifying the thermal analysis process for complex back-up antenna structures
Two-Stage Friend Recommendation Based on Network Alignment and Series Expansion of Probabilistic Topic Model
© 2017 IEEE. Precise friend recommendation is an important problem in social media. Although most social websites provide some kinds of auto friend searching functions, their accuracies are not satisfactory. In this paper, we propose a more precise auto friend recommendation method with two stages. In the first stage, by utilizing the information of the relationship between texts and users, as well as the friendship information between users, we align different social networks and choose some "possible friends." In the second stage, with the relationship between image features and users, we build a topic model to further refine the recommendation results. Because some traditional methods, such as variational inference and Gibbs sampling, have their limitations in dealing with our problem, we develop a novel method to find out the solution of the topic model based on series expansion. We conduct experiments on the Flickr dataset to show that the proposed algorithm recommends friends more precisely and faster than traditional methods
A Simple Action for a Free Anyon
By studying classical realizations of the sl(2,R) algebra in a two
dimensional phase space , we have derived a continuous family of new
actions for free anyons in 2+1 dimensions. For the case of light-like spin
vector , the action is remarkably simple. We show the
appearence of the Zitterbewegung in the solutions of the equations of motion,
and relate the actions to others in the literature at classical level.Comment: 15 pages, Plain Late
Open Access Publishing in Business Research: The Authors’ Perspective
Open access (OA) publishing is now accepted as an integral part of the emerging trends within scholarly communication. Business librarians, like their subject specialist colleagues in other disciplines, are increasingly called upon to interpret scholarly communication trends to their faculty. This study surveys 1,293 business faculty from American schools of business accredited by the Association to Advance Collegiate Schools of Business. Issues explored include business faculty publishing practices within the discipline and how these affect academic advancement, obtaining articles for their own research, electronic publishing, self-archiving, and their perceptions about OA publishing generally.With support from the Emerald Publishing Research Award 2009
Fatty liver in familial hypobetalipoproteinemia: Triglyceride assembly into VLDL particles is affected by the extent of hepatic steatosis
Familial hypobetalipoproteinemia (FHBL) subjects may develop fatty liver. Liver fat was assessed in 21 FHBL with six different apolipoprotein B (apoB) truncations (apoB-4 to apoB-89) and 14 controls by magnetic resonance spectroscopy (MRS). Liver fat percentages were 16.7 ± 11.5 and 3.3 ± 2.9 (mean ± SD) (P = 0.001). Liver fat percentage was positively correlated with body mass index, waist circumference, and areas under the insulin curves of 2 h glucose tolerance tests, suggesting that obesity may affect the severity of liver fat accumulation in both groups. Despite 5-fold differences in liver fat percentage, mean values for obesity and insulin indexes were similar. Thus, for similar degrees of obesity, FHBL subjects have more hepatic fat. VLDL-triglyceride (TG)-fatty acids arise from plasma and nonplasma sources (liver and splanchnic tissues). To assess the relative contributions of each, [2H2] palmitate was infused over 12 h in 13 FHBL subjects and 11 controls. Isotopic enrichment of plasma free palmitate and VLDL-TG-palmitate was determined by mass spectrometry. Nonplasma sources contributed 51 ± 15% in FHBL and 37 ± 13% in controls (P = 0.02). Correlations of liver fat percentage and percent VLDL-TG-palmitate from liver were r = 0.89 (P = 0.0001) for FHBL subjects and r = 0.69 (P = 0.01) for controls. Thus, apoB truncation-producing mutations result in fatty liver and in altered assembly of VLDL-TG
Radiatively Induced Lorentz and CPT Violation in Electrodynamics
In a nonperturbative formulation, radiative corrections arising from Lorentz
and CPT violation in the fermion sector induce a definite and nonzero
Chern-Simons addition to the electromagnetic action. If instead a perturbative
formulation is used, an infinite class of theories characterized by the value
of the Chern-Simons coefficient emerges at the quantum level.Comment: 4 page
Replication of linkage of familial hypobetalipoproteinemia to chromosome 3p in six kindreds
Familial hypobetalipoproteinemia (FHBL) is a genetically heterogeneous condition characterized by very low apolipoprotein B (apoB) concentrations in plasma and/or low levels of LDL-cholesterol (LDL-C) with a propensity to developing fatty liver. In a minority of cases, truncation-specifying mutations of the apoB gene (APOB) are etiologic, but the genetic basis of most cases is unknown. We previously reported linkage of FHBL to a 10 cM region on 3p21.1-22 in one kindred. The objectives of the current study were to identify other FHBL families with linkage to 3p and to narrow the FHBL susceptibility region on 3p. Six additional FHBL kindreds unlinked to the APOB region on chromosome 2 were genotyped with polymorphic markers spanning a region of approximately 13 cM on chromosome 3. Quantitative linkage analyses indicated that the FHBL in these families was linked to 3p21.1-22. Haplotype analysis identified several meiotic crossover events, allowing us to narrow the critical region from 10 cM to 2.0 cM, between markers D3S2407 and D3S1767
Failure of Gauge Invariance in the Nonperturbative Formulation of Massless Lorentz-Violating QED
We consider a Lorentz-violating modification to the fermionic Lagrangian of
QED that is known to produce a finite Chern-Simons term at leading order. We
compute the second order correction to the one-loop photon self-energy in the
massless case using an exact propagator and a nonperturbative formulation of
the theory. This nonperturbative theory assigns a definite value to the
coefficient of the induced Chern-Simons term; however, we find that the theory
fails to preserve gauge invariance at higher orders. We conclude that the
specific nonperturbative value of the Chern-Simons coefficient has no special
significance.Comment: 8 pages, very minor change
Exact calculation of the radiatively-induced Lorentz and CPT violation in QED
Radiative corrections arising from the axial coupling of charged fermions to
a constant vector b_\mu can induce a Lorentz- and CPT-violating Chern-Simons
term in the QED action. We calculate the exact one-loop correction to this term
keeping the full b_\mu dependence, and show that in the physically interesting
cases it coincides with the lowest-order result. The effect of regularization
and renormalization and the implications of the result are briefly discussed.Comment: LaTex, 8 pages; minor correction
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