24,824 research outputs found
Continuum Limits of ``Induced QCD": Lessons of the Gaussian Model at d=1 and Beyond
We analyze the scalar field sector of the Kazakov--Migdal model of induced
QCD. We present a detailed description of the simplest one dimensional
{()} model which supports the hypothesis of wide applicability of the
mean--field approximation for the scalar fields and the existence of critical
behaviour in the model when the scalar action is Gaussian. Despite the
ocurrence of various non--trivial types of critical behaviour in the
model as , only the conventional large- limit is
relevant for its {\it continuum} limit. We also give a mean--field analysis of
the model in {\it any} and show that a saddle point always exists in
the region . In it exhibits critical behaviour as
. However when there is no critical
behaviour unless non--Gaussian terms are added to the scalar field action. We
argue that similar behaviour should occur for any finite thus providing a
simple explanation of a recent result of D. Gross. We show that critical
behaviour at and can be obtained by adding a
term to the scalar potential. This is equivalent to a local
modification of the integration measure in the original Kazakov--Migdal model.
Experience from previous studies of the Generalized Kontsevich Model implies
that, unlike the inclusion of higher powers in the potential, this minor
modification should not substantially alter the behaviour of the Gaussian
model.Comment: 31 page
Title IX versus Candian Human Rights Legislation: How the United States Should Learn from Canada\u27s Human Rights Act in the Context of Sexual Harassment in Schools
This Article critically examines the success of Title IX in eradicating sexual harassment in educational settings after the Supreme Court decisions in Gebser v. Lago and Monroe v. Davis. Regrettably, the high bar for recovery established by these cases, in addition to poor administrative enforcement of Title IX have eroded its ability to maintain discrimination-free schools. After an examination of the manner in which the Canadian human rights model operates in the context of sexual harassment in educational settings, recommendations are made that the United States should use the Canadian example to improve its own system. Specifically, the United States should streamline and simplify its administrative enforcement of Title IX and articulate clearer legal standards for injunctive relief as opposed to recovery of compensatory damages
Analytical mode normalization and resonant state expansion for optical fibers - an efficient tool to model transverse disorder
We adapt the resonant state expansion to optical fibers such as capillary and
photonic crystal fibers. As a key requirement of the resonant state expansion
and any related perturbative approach, we derive the correct analytical
normalization for all modes of these fiber structures, including leaky modes
that radiate energy perpendicular to the direction of propagation and have
fields that grow with distance from the fiber core. Based on the normalized
fiber modes, an eigenvalue equation is derived that allows for calculating the
influence of small and large perturbations such as structural disorder on the
guiding properties. This is demonstrated for two test systems: a capillary
fiber and an endlessly single mode fiber.Comment: 10 pages, 4 figure
Conflicts of Interest Arising Under ERISA\u27s Fiduciary Standards: Can the Trustee Ever be Prudent, As Long As He Faces Dual Loyalties?
The drafters of the Employment Retirement Income Security Act\u27
faced the formidable task of restructuring the regulation of private
pension plans throughout America
Bose Hubbard model in the presence of Ohmic dissipation
We study the zero temperature mean-field phase diagram of the Bose-Hubbard
model in the presence of local coupling between the bosons and an external
bath. We consider a coupling that conserves the on-site occupation number,
preserving the robustness of the Mott and superfluid phases. We show that the
coupling to the bath renormalizes the chemical potential and the interaction
between the bosons and reduces the size of the superfluid regions between the
insulating lobes. For strong enough coupling, a finite value of hopping is
required to obtain superfluidity around the degeneracy points where Mott phases
with different occupation numbers coexist. We discuss the role that such a bath
coupling may play in experiments that probe the formation of the
insulator-superfluid shell structure in systems of trapped atoms.Comment: 5 pages, 2 figures. Error found in v1, now corrected, leads to
qualitative changes in result
Influences of an impurity on the transport properties of one-dimensional antisymmetric spin filter
The influences of an impurity on the spin and the charge transport of
one-dimensional antisymmetric spin filter are investigated using bosonization
and Keldysh formulation and the results are highlighted against those of
spinful Luttinger liquids. Due to the dependence of the electron spin
orientation on wave number the spin transport is not affected by the impurity,
while the charge transport is essentially identical with that of spinless
one-dimensional Luttinger liquid.Comment: 7 pages, 2 figures. To appear in Physical Review
Sexual behaviour and HIV/sexually transmitted infection risk behaviours in the general population of Slovenia, a low HIV prevalence country in central Europe.
OBJECTIVES: To describe sexual and HIV/sexually transmitted infection (STI) risk behaviours in Slovenia. METHODS: A nationally representative cross-sectional survey of the general population aged 18-49 years in 1999-2001 was conducted. The data were collected by face-to-face interviews and anonymous self-administered questionnaires. Statistical methods for complex survey data were used. RESULTS: 849 men and 903 women were interviewed. In the past 5 years, both men and women reported a median of one heterosexual partner (means 3.2, 1.5, respectively), concurrent heterosexual partnerships were reported by 24.4% of men and 8.2% of women, heterosexual sex with non-Slovenian partners by 12.6% of men and 12.2% of women, forced sex by 4.8% of women, paid heterosexual sex by 2.6% of men, sex with another man by 0.6% of men and heterosexual sex with an injecting drug user by 1.2% of men and 1.3% of women. In the past year, 22.7% of men and 9.5% of women reported forming at least one new heterosexual partnership. The mean numbers of episodes of heterosexual sex in the previous 4 weeks were 6.1 for men and 6.0 for women. Consistent and inconsistent condom use was reported more frequently among men reporting multiple female partners and those not married or cohabiting. CONCLUSIONS: Recent patterns of reported sexual behaviour are consistent with a low risk of HIV and STI transmission in Slovenia. The results will inform Slovenian sexual health policies including HIV/STI prevention, and are particularly valuable because population-based data on HIV/STI risk behaviour have not previously been available in low HIV prevalence countries of central Europe
A Generalised Sidelobe Canceller Architecture Based on Oversampled Subband Decompositions
Adaptive broadband beamforming can be performed in oversampled subband signals, whereby an independent beamformer is operated in each frequency band. This has been shown to result in a considerably reduced computational complexity. In this paper, we primarily investigate the convergence behaviour of the generalised sidelobe canceller (GSC) based on normalised least mean squares algorithm (NLMS) when operated in subbands. The minimum mean squared error can be limited, amongst other factors, by the aliasing present in the subbands. With regard to convergence speed, there is strong indication that the subband-GSC converges faster than a fullband counterpart of similar modelling capabilities. Simulations are presented
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