Periastron shift in Weyl class spacetimes

The periastron position advance for geodesic motion in axially symmetric solutions of the Einstein field equations belonging to the Weyl class of vacuum solutions is investigated. Explicit examples corresponding to either static solutions (single Chazy-Curzon, Schwarzschild and a pair of them), or stationary solution (single rotating Chazy-Curzon and Kerr black hole) are discussed. The results are then applied to the case of S2-SgrA$^*$ binary system of which the periastron position advance will be soon measured with a great accuracy.Comment: To appear on General Relativity and Gravitation, vol. 37, 200

Ингибирование активности каспазы-2 в клетках Т-клеточной лимфомы человека Jurkat при помощи переключающего сплайсинг олигонуклеотида к её пре-мРНК

Caspase-2 is a key enzyme thinvolved in induction of apoptosis. The caspase-2 level is regulated by alternative splicing (AS) of its mRNA. The aim of this work was to determine the ability of an oligonucleotide complementary to Casp-2 pre-mRNA to induce AS. This oligonucleotide blocked the binding of splicing-regulating proteins to their sites at the end of exon 9 of Casp-2 pre-mRNA, leading to induction of AS of Casp-2 mRNA. The decrease in expression of full-size active splice-variant (Casp-2L) and the increase the expression of a shortened variant (Casp-2S) was demonstrated in human T-cell lymphoma Jurkat cell line. The expression level of total Casp-2 remained unchanged. Disproportion of splice variants of Casp-2 led to inhibition of enzymatic activity of caspase-2.Каспаза-2 является ферментом, участвующим в индукции апоптоза. Количество активного фермента каспазы-2 регулируется альтернативным сплайсингом (АС) её мРНК. Целью данной работы было определение способности олигонуклеотида, комплементарного пре-мРНК Casp-2, индуцировать АС. Данный олигонуклеотид блокировал связывание регулирующих сплайсинг белков со своими сайтами на конце экзона 9 пре-мРНК Casp-2, что приводило к индукции АС мРНК Casp-2: понижению экспрессии полноразмерного активного сплайс-варианта Casp-2L и повышению экспрессии укороченного варанта Casp-2S в клетках Т-клеточной лимфомы человека линии Jurkat. При этом уровень экспрессии общей Casp-2 не изменялся. Нарушуение пропорции сплайс-вариантов Casp-2 приводил к ингибированию ферментативной активности каспазы-2

Vacuum polarization by a global monopole with finite core

We investigate the effects of a $(D+1)$-dimensional global monopole core on the behavior of a quantum massive scalar field with general curvature coupling parameter. In the general case of the spherically symmetric static core, formulae are derived for the Wightman function, for the vacuum expectation values of the field square and the energy-momentum tensor in the exterior region. These expectation values are presented as the sum of point-like global monopole part and the core induced one. The asymptotic behavior of the core induced vacuum densities is investigated at large distances from the core, near the core and for small values of the solid angle corresponding to strong gravitational fields. In particular, in the latter case we show that the behavior of the vacuum densities is drastically different for minimally and non-minimally coupled fields. As an application of general results the flower-pot model for the monopole's core is considered and the expectation values inside the core are evaluated.Comment: 22 pages, 4 figures, misprint is corrected, discussion is added, figures are change

Effects of Anomalous Magnetic Moment in the Quantum Motion of Neutral Particle in Magnetic and Electric Fields Produced by a Linear Source in a Conical Spacetime

In this paper we analyse the effect of the anomalous magnetic moment on the non-relativistic quantum motion of a neutral particle in magnetic and electric fields produced by linear sources of constant current and charge density, respectively.Comment: 17 pages, no figur

Self-energy and Self-force in the Space-time of a Thick Cosmic String

We calculate the self-energy and self-force for an electrically charged particle at rest in the background of Gott-Hiscock cosmic string space-time. We found the general expression for the self-energy which is expressed in terms of the $S$ matrix of the scattering problem. The self-energy continuously falls down outward from the string's center with maximum at the origin of the string. The self-force is repulsive for an arbitrary position of the particle. It tends to zero in the string's center and also far from the string and it has a maximum value at the string's surface. The plots of the numerical calculations of the self-energy and self-force are shown.Comment: 15 pages, 4 Postscript figures, ReVTe

Cosmic microwave background anisotropies in multi-connected flat spaces

This article investigates the signature of the seventeen multi-connected flat spaces in cosmic microwave background (CMB) maps. For each such space it recalls a fundamental domain and a set of generating matrices, and then goes on to find an orthonormal basis for the set of eigenmodes of the Laplace operator on that space. The basis eigenmodes are expressed as linear combinations of eigenmodes of the simply connected Euclidean space. A preceding work, which provides a general method for implementing multi-connected topologies in standard CMB codes, is then applied to simulate CMB maps and angular power spectra for each space. Unlike in the 3-torus, the results in most multi-connected flat spaces depend on the location of the observer. This effect is discussed in detail. In particular, it is shown that the correlated circles on a CMB map are generically not back-to-back, so that negative search of back-to-back circles in the WMAP data does not exclude a vast majority of flat or nearly flat topologies.Comment: 33 pages, 19 figures, 1 table. Submitted to PR

Efficient Raman Sideband Generation in a Coherent Atomic Medium

We demonstrate the efficient generation of Raman sidebands in a medium coherently prepared in a dark state by continuous-wave low-intensity laser radiation. Our experiment is performed in sodium vapor excited in $\Lambda$ configuration on the D$_{1}$ line by two laser fields of resonant frequencies $\omega_{1}$ and $\omega_{2}$, and probed by a third field $$. First-order sidebands for frequencies $\omega_{1}$, $\omega_{2}$ and up to the third-order sidebands for frequency $\omega_{3}$ are observed. The generation starts at a power as low as 10 microwatt for each input field. Dependencies of the intensities of both input and generated waves on the frequency difference ($\omega_{1}-\omega_{2}$), on the frequency $\omega_{3}$ and on the optical density are investigated.Comment: 7 pages, 6 figure

Heat-kernels and functional determinants on the generalized cone

We consider zeta functions and heat-kernel expansions on the bounded, generalized cone in arbitrary dimensions using an improved calculational technique. The specific case of a global monopole is analysed in detail and some restrictions thereby placed on the $A_{5/2}$ coefficient. The computation of functional determinants is also addressed. General formulas are given and known results are incidentally, and rapidly, reproduced.Comment: 26p,LaTeX.(Cosmetic changes and eqns (9.8),(11.2) corrected.

Racetrack Inflation

We develop a model of eternal topological inflation using a racetrack potential within the context of type IIB string theory with KKLT volume stabilization. The inflaton field is the imaginary part of the K\"ahler structure modulus, which is an axion-like field in the 4D effective field theory. This model does not require moving branes, and in this sense it is simpler than other models of string theory inflation. Contrary to single-exponential models, the structure of the potential in this example allows for the existence of saddle points between two degenerate local minima for which the slow-roll conditions can be satisfied in a particular range of parameter space. We conjecture that this type of inflation should be present in more general realizations of the modular landscape. We also consider `irrational' models having a dense set of minima, and discuss their possible relevance for the cosmological constant problem.Comment: 23 pages 7 figures. The final version with minor modifications, to appear in JHE

Gravitational hedgehog, stringy hedgehog and stringy sphere

We investigate the solutions of Einstein equations such that a hedgehog solution is matched to different exterior or interior solutions via a spherical shell. In the case where both the exterior and the interior regions are hedgehog solutions or one of them is flat, the resulting spherical shell becomes a stringy shell. We also consider more general matchings and see that in this case the shell deviates from its stringy character.Comment: 11 page