685 research outputs found
Extra dimensions and the strong CP problem
In higher-dimensional theories such as Brane World models with
quasi-localized non-Abelian gauge fields the vacuum structure turns out to be
trivial. Since the gauge theory behaves at large distances as a
-dimensional and thus the topology of the infinity is that of of
rather than , the set of gauge mappings are homotopically
trivial and the CP-violating -term vanishes on the brane world-volume.
As well there are no contributions to the -term from the
higher-dimensional solitonic configurations. In this way, the strong CP problem
is absent in the models with quasi-localized gluons.Comment: 7 pp., latex, no figure
An Analysis of Four-quark Energies in SU(2) Lattice Monte Carlo using the Flux-tube Symmetry:
Energies of four-quark systems calculated by the static quenched SU(2)
lattice Monte Carlo method are analyzed in bases for square,
rectangle, tilted rectangle, linear and quadrilateral geometry configurations
and in bases for a non-planar geometry configuration. For small
interquark distances, a lattice effect is taken into account by considering
perimeter dependent terms which are characterized by the cubic symmetry. It is
then found that a parameter - that can be identified as a gluon field
overlap factor - is rather well described by the form , where and are the area and
perimeter mainly defined by the positions of the four quarks, is the
string constant in the 2-quark potentials and are constants.Comment: (19 pages of Latex - 1 page of figures not included - sent on
request). Preprint HU-TFT-94-2
Does Trade Openness Affect Bank Risk-Taking Behavior? Evidence from BRICS Countries
In this paper, we examine the impact of trade openness on bank risk-taking behavior employing a panel dataset of 899 banks from the BRICS (i.e., Brazil, Russia, India, China, and South Africa) countries over the period 2000–2017. We find that higher trade openness lowers bank risk-taking. Our results are robust when we use alternative proxies of trade openness and bank risk-taking, estimate country-wise regressions, or use alternative estimation methods such as system Generalized Methods of Moments (GMM), fixed effects, pooled Ordinary Least Square (OLS), and Vector Error Correction Model (VECM) models. We also observe higher trade openness decreases bank risk-taking in both the short and long run. Moreover, banks in more open countries perform relatively better during the crisis period further signifying the diversification benefits of openness. Together, our findings imply the beneficial impact of trade openness for financial sector stability
Trouble with the Lorentz law of force: Incompatibility with special relativity and momentum conservation
The Lorentz law of force is the fifth pillar of classical electrodynamics,
the other four being Maxwell's macroscopic equations. The Lorentz law is the
universal expression of the force exerted by electromagnetic fields on a volume
containing a distribution of electrical charges and currents. If electric and
magnetic dipoles also happen to be present in a material medium, they are
traditionally treated by expressing the corresponding polarization and
magnetization distributions in terms of bound-charge and bound-current
densities, which are subsequently added to free-charge and free-current
densities, respectively. In this way, Maxwell's macroscopic equations are
reduced to his microscopic equations, and the Lorentz law is expected to
provide a precise expression of the electromagnetic force density on material
bodies at all points in space and time. This paper presents incontrovertible
theoretical evidence of the incompatibility of the Lorentz law with the
fundamental tenets of special relativity. We argue that the Lorentz law must be
abandoned in favor of a more general expression of the electromagnetic force
density, such as the one discovered by A. Einstein and J. Laub in 1908. Not
only is the Einstein-Laub formula consistent with special relativity, it also
solves the long-standing problem of "hidden momentum" in classical
electrodynamics.Comment: 7 pages, 1 figur
Effect of Ispaghula and Oxyphenonium Bromide on the Symptoms of Irritable Bowel Syndrome - A Comparative Study
Background: Irritable bowel syndrome is a chronic continuous or remittent gastrointestinal illness characterized byfrequent unexplained symptoms that include abdominal pain, bloating, and bowel disturbance, in our country, no studyhas been conducted using the Ispaghula husk and oxyphenonium bromide for the treatment of IBS patients. Objectives:To compare the efficacy of treatment with Ispaghula husk and Oxyphenonium bromide. Methods: Total sixty patientsdiagnosed clinically as irritable bowel syndrome irrespective of subtype who fulfilled the Rome II criteria were includedequally into two groups-Group-I (Ispaghula group) & Group-II (Oxyphenonium group). In Group-I patients were given30gm of Ispaghula husk at night daily and in Group-II patients were given 5mg of oxyphenonium bromide. After sixweeks the clinical parameters of both the groups recorded in the case record forms were taken for analysis. Results: Themean age of the patients in the Group- I were 33.4±11.9 yrs and that of the patients in the Group-II were 31.0±17.5 yrs.Male and female ratio in group I was 14:1 and in group II was 23:7. Most of the patients were recorded in the age groupof 26-30 in both groups. Symptom free patients were graded in 16.7% patients in Group-I and in 20% patients in Group-II. No improvement was occurred in 16.7% patients in Group-I and in 10% patients in Group-II. Conclusions: Ispaghulahusk shows the better efficacy to improve the symptoms of IBS like abdominal pain or discomfort and sense of well beingthan Oxyphenonium bromide. Oxephenonium bromide shows the better efficacy to decrease the stool frequency frombase line than Ispaghula husk.DOI: 10.3329/bsmmuj.v3i1.5506BSMMU J 2010; 3(1): 3-
Dirac Quantization Condition for Monopole in Noncommutative Space-Time
Since the structure of space-time at very short distances is believed to get
modified possibly due to noncommutativity effects and as the Dirac Quantization
Condition (DQC), , probes the magnetic field point
singularity, a natural question arises whether the same condition will still
survive. We show that the DQC on a noncommutative space in a model of dynamical
noncommutative quantum mechanics remains the same as in the commutative case to
first order in the noncommutativity parameter , leading to the
conjecture that the condition will not alter in higher orders.Comment: 11 page
Statistics of non-linear stochastic dynamical systems under L\'evy noises by a convolution quadrature approach
This paper describes a novel numerical approach to find the statistics of the
non-stationary response of scalar non-linear systems excited by L\'evy white
noises. The proposed numerical procedure relies on the introduction of an
integral transform of Wiener-Hopf type into the equation governing the
characteristic function. Once this equation is rewritten as partial
integro-differential equation, it is then solved by applying the method of
convolution quadrature originally proposed by Lubich, here extended to deal
with this particular integral transform. The proposed approach is relevant for
two reasons: 1) Statistics of systems with several different drift terms can be
handled in an efficient way, independently from the kind of white noise; 2) The
particular form of Wiener-Hopf integral transform and its numerical evaluation,
both introduced in this study, are generalizations of fractional
integro-differential operators of potential type and Gr\"unwald-Letnikov
fractional derivatives, respectively.Comment: 20 pages, 5 figure
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