238 research outputs found
Topologically Massive Gauge Theory: A Lorentzian Solution
We obtain a lorentzian solution for the topologically massive non-abelian
gauge theory on AdS space by means of a SU(1, 1) gauge transformation of the
previously found abelian solution. There exists a natural scale of length which
is determined by the inverse topological mass. The topological mass is
proportional to the square of the gauge coupling constant. In the topologically
massive electrodynamics the field strength locally determines the gauge
potential up to a closed 1-form via the (anti-)self-duality equation. We
introduce a transformation of the gauge potential using the dual field strength
which can be identified with an abelian gauge transformation. Then we present
the map from the AdS space to the pseudo-sphere including the topological mass.
This is the lorentzian analog of the Hopf map. This map yields a global
decomposition of the AdS space as a trivial circle bundle over the upper
portion of the pseudo-sphere which is the Hyperboloid model for the Lobachevski
geometry. This leads to a reduction of the abelian field equation onto the
pseudo-sphere using a global section of the solution on the AdS space. Then we
discuss the integration of the field equation using the Archimedes map from the
pseudo-sphere to the cylinder over the ideal Poincare circle. We also present a
brief discussion of the holonomy of the gauge potential and the dual-field
strength on the upper portion of the pseudo-sphere.Comment: 23 pages, 1 postscript figur
Histopathological effects of maternal hair dye use on the cornea
The aim of this study is to investigate and compare the histopathological effects of hair dye additives, 2- amino-5-nitrophenol (2A5NP) and 2-nitro-p-phenylendiamin (2NPPD) on cornea of neonates from pregnant rats that have been administered these additives subcutaneously. The study included 90 neonates of 26 nulligravida wistar-albino rats among which ten were given 100 mg/kg/day 2A5NP (Group I), ten rats received 150 mg/kg/day 2NPPD (Group II) and control rats received saline (Group III) injections subcutaneously between 7th and 15th gestational days. No sign of toxicity was observed during the treatment and there was no gross abnormality in both the study and control groups. Histopathologicalchanges of cornea were seen in 22 of 30 newborn rats in Group I (73.4%), in 23 of 30 rats in Group II (76.7%) and only 5 of 30 rats in the control saline injected Group III (16.7%). Histopathological effect of the two additives were statistically significant when compared to the control group (Chi-square:27.63, p = 0.0001), but there was no difference between the effects of 2A5NP and 2NPPD additives on cornea (Chisquare: 0.089, p = 0.766). The present experimental study on rats confirmed the histopathological effect of 2A5NP and 2NPPD on cornea beyond doubt. In the light of which, we can speculate that maternal exposure of hair dyes during pregnancy has some teratogenic effects on newborn rat cornea
Distribution and Excretion of TEGDMA in Guinea Pigs and Mice
The monomer triethyleneglycoldimethacrylate (TEGDMA) is used as a diluent in many resin-based dental materials. It was previously shown in vitro that TEGDMA was released into the adjacent biophase from such materials during the first days after placement. In this study, the uptake, distribution, and excretion of 14C-TEGDMA applied via gastric, intradermal, and intravenous administration at dose levels well above those encountered in dental care were examined in vivo in guinea pigs and mice as a test of the hypothesis that TEGDMA reaches cytotoxic levels in mammalian tissues. 14C-TEGDMA was taken up rapidly from the stomach and small intestine after gastric administration in both species and was widely distributed in the body following administration by each route. Most 14C was excreted within one day as 14 CO2. The peak equivalent TEGDMA levels in all mouse and guinea pig tissues examined were at least 1000-fold less than known toxic levels. The study therefore did not support the hypothesis
Initial Hypersurface Formulation: Hamilton-Jacobi Theory for Strongly Coupled Gravitational Systems
Strongly coupled gravitational systems describe Einstein gravity and matter
in the limit that Newton's constant G is assumed to be very large. The
nonlinear evolution of these systems may be solved analytically in the
classical and semiclassical limits by employing a Green function analysis.
Using functional methods in a Hamilton-Jacobi setting, one may compute the
generating functional (`the phase of the wavefunctional') which satisfies both
the energy constraint and the momentum constraint. Previous results are
extended to encompass the imposition of an arbitrary initial hypersurface. A
Lagrange multiplier in the generating functional restricts the initial fields,
and also allows one to formulate the energy constraint on the initial
hypersurface. Classical evolution follows as a result of minimizing the
generating functional with respect to the initial fields. Examples are given
describing Einstein gravity interacting with either a dust field and/or a
scalar field. Green functions are explicitly determined for (1) gravity, dust,
a scalar field and a cosmological constant and (2) gravity and a scalar field
interacting with an exponential potential. This formalism is useful in solving
problems of cosmology and of gravitational collapse.Comment: 30 pages Latex (IOP) file with 2 IOP style files, to be published in
Classical and Quantum Gravity (1998
Myeloperoxidase enzyme levels and oxidative stress in bipolar disorders
Oxidative stress and generalized inflammatory state are features of bipolar disorders (BD). The objective of this study was to compare the levels of products of inflammatory reaction and oxidative stress markers in patients with bipolar disorders and attention deficit/hyperactivity disorder (ADHD) and to determine the relationship between oxidative stress and inflammation in bipolar disorders. ADHD+BD (n = 30) and BD (n = 30) and healthy controls (n = 30) were enrolled. A clinical evaluation andmeasurements of malondialdehyde (MDA), high sensitive C reactive protein (hsCRP) and myeloperoxidase (MPO) were performed. Patients with BD+ADHD comorbidity had significantly higher mean MPO levels than BD. Patients with BD had significantly higher mean hsCRP levels than healthy controls. However, there was no significant difference in mean serum hsCRP levels between patients with BD+ADHD and healthy controls. Patients with BD and BD+ADHD had significantly higher mean MDA levels than healthy controls. Our data showed that there is an increased susceptibility to oxidative stress which is strongly related to the serum levels of MDA produced in the serum. hsCRP levels were higher in BD patients than in BD+ADHD and this is suggestive of a higher degree of inflammatory activity in BD patients. ADHD+BD comorbidity seems to augment oxidative stress which is expressed as increased MPO level in the present study. Further large scale studies are needed to extend ourresults
Анализ технологий по предупреждению формирования газовых гидратов на Заполярном нефтегазоконденсатном месторождении (ЯНАО)
Объектами исследования являются осложнения, возникающие при гидратоотложении в системах сбора и транспортировки газа. Предметом исследования являются комплексные методы предупреждения образования гидратов природного газа. Цель выпускной квалификационной работы – анализ методов и технологий защиты промыслового оборудования от осложнений, вызванных гидратообразованием.The objects of the following research are the problems appearing from the hydrate formation in gas gathering facilities and transportation systems. The subjects of the research are complex methods of preventing the formation of natural gas hydrates. The purpose of the graduation thesis is to analyze methods and technologies for protecting field equipment from problems caused by hydrate formation
Trkalian fields: ray transforms and mini-twistors
We study X-ray and Divergent beam transforms of Trkalian fields and their
relation with Radon transform. We make use of four basic mathematical methods
of tomography due to Grangeat, Smith, Tuy and Gelfand-Goncharov for an integral
geometric view on them. We also make use of direct approaches which provide a
faster but restricted view of the geometry of these transforms. These reduce to
well known geometric integral transforms on a sphere of the Radon or the
spherical Curl transform in Moses eigenbasis, which are members of an analytic
family of integral operators. We also discuss their inversion. The X-ray (also
Divergent beam) transform of a Trkalian field is Trkalian. Also the Trkalian
subclass of X-ray transforms yields Trkalian fields in the physical space. The
Riesz potential of a Trkalian field is proportional to the field. Hence, the
spherical mean of the X-ray (also Divergent beam) transform of a Trkalian field
over all lines passing through a point yields the field at this point. The
pivotal point is the simplification of an intricate quantity: Hilbert transform
of the derivative of Radon transform for a Trkalian field in the Moses basis.
We also define the X-ray transform of the Riesz potential (of order 2) and
Biot-Savart integrals. Then, we discuss a mini-twistor respresentation,
presenting a mini-twistor solution for the Trkalian fields equation. This is
based on a time-harmonic reduction of wave equation to Helmholtz equation. A
Trkalian field is given in terms of a null vector in C3 with an arbitrary
function and an exponential factor resulting from this reduction.Comment: 37 pages, http://dx.doi.org/10.1063/1.482610
Закономерности распределения и аккумуляции ртути в представителях ихтиофауны озера Байкал (Республика Бурятия)
Изучена экологическая ситуация в районе озера Байкал, особенности и закономерности распределения и аккумуляции ртутив представителях ихтиофауны озера Байкал.The ecological situation in the area of Baikal lakes, the features of the distribution and accumulation of reserves in Baikal are studied
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