42,041 research outputs found
The engagement of mature distance students
This is an Accepted Manuscript of an article published by Taylor & Francis in Higher Education Research and Development in 2013, available online: http://www.tandfonline.com/10.1080/07294360.2013.777036.Publishe
Superstring BRST Cohomology
We first derive all world-sheet action functionals for NSR superstring models
with (1,1) supersymmetry and any number of abelian gauge fields, for gauge
transformations of the standard form. Then we prove for these models that the
BRST cohomology groups , (with the antifields taken into account)
are isomorphic to those of the corresponding bosonic string models, whose
cohomology is fully known. This implies that the nontrivial global symmetries,
Noether currents, background charges, consistent deformations and candidate
gauge anomalies of an NSR (1,1) superstring model are in one-to-one
correspondence with their bosonic counterparts.Comment: LaTeX2e, 44 pages, minor correction
From multiple integrals to Fredholm determinants
We consider a multiple integral representation for the finite temperature
density-density correlation functions of the one-dimensional Bose gas with
delta function interaction in the limits of infinite and vanishing repulsion.
In the former case a known Fredholm determinant is recovered. In the latter
case a similar expression appears with permanents replacing determinants.Comment: 11 pages, section on the free Boson limit adde
Spatial Compressive Sensing for MIMO Radar
We study compressive sensing in the spatial domain to achieve target
localization, specifically direction of arrival (DOA), using multiple-input
multiple-output (MIMO) radar. A sparse localization framework is proposed for a
MIMO array in which transmit and receive elements are placed at random. This
allows for a dramatic reduction in the number of elements needed, while still
attaining performance comparable to that of a filled (Nyquist) array. By
leveraging properties of structured random matrices, we develop a bound on the
coherence of the resulting measurement matrix, and obtain conditions under
which the measurement matrix satisfies the so-called isotropy property. The
coherence and isotropy concepts are used to establish uniform and non-uniform
recovery guarantees within the proposed spatial compressive sensing framework.
In particular, we show that non-uniform recovery is guaranteed if the product
of the number of transmit and receive elements, MN (which is also the number of
degrees of freedom), scales with K(log(G))^2, where K is the number of targets
and G is proportional to the array aperture and determines the angle
resolution. In contrast with a filled virtual MIMO array where the product MN
scales linearly with G, the logarithmic dependence on G in the proposed
framework supports the high-resolution provided by the virtual array aperture
while using a small number of MIMO radar elements. In the numerical results we
show that, in the proposed framework, compressive sensing recovery algorithms
are capable of better performance than classical methods, such as beamforming
and MUSIC.Comment: To appear in IEEE Transactions on Signal Processin
ENGINE PERFORMANCE ON ATOMIZATION OF FUEL INJECTOR: A REVIEW
The impact of the fuel injection of fuel atoms on engine performance has been investigated to improve fuel efficiency and waste disposal features. The fuel swirl method for injection atomization was evaluated both by the analysis of the fuel flow and the sample test. The goal of the paper is to establish good fuel atomization over the range of engine performance. As a result of our studies, it has been concluded that the desired atomization can be achieved when gasoline is thrown into a circular motion. Fuel spray and atomization features play an important role in the performance of internal combustion engines. An atomization study to evaluate the numerical fuel injection used in the IGC (Inner Guide-vane Combustor) under various combination and performance conditions has been performed to determine the suspension of the proposed fuel injection to be used in the IGC. Additional results have shown that a single-hole fuel injection, forward injection direction, and a splash of
Super Landau-Ginzburg mirrors and algebraic cycles
We investigate the super Landau-Ginzburg mirrors of gauged linear sigma
models which, in an appropriate low energy limit, reduce to nonlinear sigma
models with Kaehler supermanifold target spaces of nonnegative super-first
Chern class.Comment: 29 pages, 5 figures, uses edited version of jheppub.sty. Dedicated to
our dear friend and coauthor Maximilian Kreuzer, who died November 26, 2010.
v3: Modifications to the Introduction, Equations (4.2), (5.2), and (6.2), and
Remark 8.2. v2: Theorem A.1 and Corollary A.1 corrected; corresponding
changes made in Section 4. Minor change in Section 2. Minor changes in
Section
Bringing research results to users: the case for a knowledge resource centre
Poster presented at Scientific and Technical Information and Rural Development: Highlights of Innovative Practices. 13. IAALD World Congress. Montpellier (France), 26-29 Apr 201
Therapy of Canine Hyperlipidemia with Bezafibrate.
BackgroundBezafibrate (BZF) is effective in the treatment of hypertriglyceridemia in human patients, but there are no data on its use in dogs.ObjectiveTo assess the safety of BZF in hyperlipidemic dogs and its efficacy in decreasing serum triglyceride (TG) and cholesterol (CHO) concentrations.AnimalsForty-six dogs, 26 females and 20 males, mean (±SD) age of 9 (±3) years, with TG ≥150 mg/dL (33 dogs also were hypercholesterolemic [>300 mg/dL]).MethodsProspective, uncontrolled clinical trial. Dogs were treated with bezafibrate once daily, using 200 mg tablets at a dosage of 4-10 mg/kg (depending on body weight). Serum TG and CHO concentrations and alanine aminotransferase (ALT) and creatine kinase (CK) activity before and after 30 days of treatment were compared.ResultsSixteen dogs (34.8%) had primary hyperlipidemia, and 30 dogs (65.2%) had secondary hyperlipidemia (including spontaneous hyperadrenocorticism [41.3%, n = 19/46], chronic treatment with glucocorticoids [10.8%, n = 5/46], and hypothyroidism [15.2%, n = 7/46]). After 30 days, serum TG concentration normalized (<150 mg/dL) in 42 dogs (91.3%) and CHO concentration normalized (<270 mg/dL) in 22 of 33 dogs (66.7%). There was no difference in baseline TG concentration between the primary and secondary hyperlipidemia subgroups, but the decrease in TG concentration after treatment was greater in the primary hyperlipidemia subgroup. No adverse effects were observed, but ALT activity decreased significantly after 30 days of treatment.Conclusions and clinical importanceOver 30 days, BZF was safe and effective in treatment of primary and secondary hyperlipidemia in dogs
Spinodal Instabilities in Nuclear Matter in a Stochastic Relativistic Mean-Field Approach
Spinodal instabilities and early growth of baryon density fluctuations in
symmetric nuclear matter are investigated in the basis of stochastic extension
of relativistic mean-field approach in the semi-classical approximation.
Calculations are compared with the results of non-relativistic calculations
based on Skyrme-type effective interactions under similar conditions. A
qualitative difference appears in the unstable response of the system: the
system exhibits most unstable behavior at higher baryon densities around
in the relativistic approach while most unstable
behavior occurs at lower baryon densities around in
the non-relativistic calculationsComment: 18 pages, 7 figure
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