Mass and angular momentum of asymptotically AdS or flat solutions in the topologically massive gravity

We study the conserved charges of supersymmetric solutions in the topologically massive gravity theory for both asymptotically flat and constant curvature geometries.Comment: REVTEX4, 8 pages, no figures, added 2 references and a few clarifying remark

Solvegeometry gravitational waves

In this paper we construct negatively curved Einstein spaces describing gravitational waves having a solvegeometry wave-front (i.e., the wave-fronts are solvable Lie groups equipped with a left-invariant metric). Using the Einstein solvmanifolds (i.e., solvable Lie groups considered as manifolds) constructed in a previous paper as a starting point, we show that there also exist solvegeometry gravitational waves. Some geometric aspects are discussed and examples of spacetimes having additional symmetries are given, for example, spacetimes generalising the Kaigorodov solution. The solvegeometry gravitational waves are also examples of spacetimes which are indistinguishable by considering the scalar curvature invariants alone.Comment: 10 pages; v2:more discussion and result

Holographic flows to IR Lifshitz spacetimes

Recently we studied `vanishing' horizon limits of `boosted' black D3-brane geometry \cite{hsnr}. The type IIB solutions obtained by taking these special double limits were found to describe nonrelativistic Lifshitz spacetimes at zero temperature. In the present work we study these limits for TsT black-hole solutions which include $B$-field. The new Galilean solutions describe a holographic RG flow from Schr\"odinger ($a=2$) spacetime in UV to a Lifshitz universe ($a=3$) in the IR.Comment: 10 pages; v2: A bad typo in eq.8 corrected; v3: Discussion and reference on Kaigorodov spaces included, correction in sec-3, to be published in JHE

Embeddings in Non-Vacuum Spacetimes

A scheme is discussed for embedding n-dimensional, Riemannian manifolds in an (n+1)-dimensional Einstein space. Criteria for embedding a given manifold in a spacetime that represents a solution to Einstein's equations sourced by a massless scalar field are also discussed. The embedding procedures are illustrated with a number of examples.Comment: 17 pages, Plain Latex. Extended discussion on embeddings with scalar fields and further examples included. In press, Classical and Quantum Gravit

The structure of cool accretion disc in semidetached binaries

We present the results of qualitative consideration of possible changes occurring during the transition from the hot accretion disc to the cool one. We argue the possible existence of one more type of spiral density waves in the inner part of the disc where gasdynamical perturbations are negligible. The mechanism of formation of such a wave as well as its parameters are considered. We also present the results of 3D gasdynamical simulation of cool accretion discs. These results confirm the hypothesis of possible formation of the spiral wave of a new, "precessional" type in the inner regions of the disc. Possible observational manifestations of this wave are discussed.Comment: LaTeX, 16 pages, 8 figures, to be published in Astron. Z

A model of superoutbursts in binaries of SU UMa type

A new mechanism explaining superoutbursts in binaries of SU UMa type is proposed. In the framework of this mechanism the accretion rate increase leading to the superoutburst is associated with formation of a spiral wave of a new "precessional" type in inner gasdynamically unperturbed parts of the accretion disc. The possibility of existence of this type of waves was suggested in our previous work (astro-ph/0403053). The features of the "precessional" spiral wave allow explaining both the energy release during the outburst and all its observational manifestations. The distinctive characteristic of a superoutburst in a SU UMa type star is the appearance of the superhump on the light curve. The proposed model reproduces well the formation of the superhump as well as its observational features, such as the period that is 3-7% longer than the orbital one and the detectability of superhumps regardless of the binary inclination.Comment: LaTeX, 20 pages, 4 figures, to be published in Astron. Z

Lifshitz/Schr\"odinger D-p-branes and dynamical exponents

We extend our earlier study of special double limits of `boosted' $AdS_5$ black hole solutions to include all black D$p$-branes of type II strings. We find that Lifshitz solutions can be obtained in generality, with varied dynamical exponents, by employing these limits. We then study such double limits for `boosted' D$p$-brane bubble solutions and find that the resulting non-relativistic solutions instead describe Schr\"odinger like spacetimes, having varied dynamical exponents. We get a simple map between these Lifshitz & Schr\"odinger solutions and a relationship between two types of dynamical exponents. We also discuss about the singularities of the Lifshitz solutions and an intriguing thermodynamic duality.Comment: 20 pages; 3 figures; v3: similar to JHE

Interpretation of the Siklos solutions as exact gravitational waves in the anti-de Sitter universe

The Siklos class of solutions of Einstein's field equations is investigated by analytical methods. By studying the behaviour of free particles we reach the conclusion that the space-times represent exact gravitational waves propagating in the anti-de Sitter universe. The presence of a negative cosmological constant implies that the 'background' space is not asymptotically flat and requires a 'rotating' reference frames in order to fully simplify and view the behaviour of nearby test particles. The Kaigorodov space-time, which is the simplest representative of the Siklos class, is analyzed in more detail. It is argued that it may serve as a 'cosmological' analogue of the well-known homogeneous pp-waves in the flat universe.Comment: 17 pages, to be published in Class. Quantum Gravit

Universal time-dependent deformations of Schrodinger geometry

We investigate universal time-dependent exact deformations of Schrodinger geometry. We present 1) scale invariant but non-conformal deformation, 2) non-conformal but scale invariant deformation, and 3) both scale and conformal invariant deformation. All these solutions are universal in the sense that we could embed them in any supergravity constructions of the Schrodinger invariant geometry. We give a field theory interpretation of our time-dependent solutions. In particular, we argue that any time-dependent chemical potential can be treated exactly in our gravity dual approach.Comment: 24 pages, v2: references adde

Исследование эффективности лечения больных хронической обструктивной болезнью легких препаратом Спирива (тиотропия бромид) в Новосибирской области

A regional branch programme "Improvement of quality of life of COPD patients" had been developed and adopted at Novosibirsk region. Its content is financial support and organization of COPD treatment using thiotropium bromide. The study involved 35 COPD patients, 31of them (28 males and 3 females) completed the treatment. The average age of participants was 53.2 ± 3.9 yrs. We assessed severity of clinical signs using a 3-point scale; spirometry parameters, physical tolerability in 6-minute walk test. We also calculated cost of therapy of COPD patients. The follow-up duration was 6 months. Results demonstrated a significant reduction in clinical severity of COPD, improvement in functional capacity during the treatment with Spiriva. The rate of seeking for aid, number of seek days and length of staying in a hospitals decreased. Medical expenses for COPD treatment increased when used Spiriva due to its high cost but with regards to a total expenditure (direct and indirect) the cost-efficacy was 32.7 %.В Новосибирской области разработана и принята областная отраслевая программа "Повышение качества жизни больных ХОБЛ", содержание которой заключалось в финансировании и организации мероприятий по лечению ХОБЛ препаратом тиотропия бромид. В исследовании участвовали 35 больных ХОБЛ, из которых завершили лечение 31 человек (28 мужчин и 3 женщины). Средний возраст участников составил 53,2 ± 3,9 лет. Оценивали выраженность симптомов заболевания по 3-балльной шкале, показатели спирометрии, толерантность к физической нагрузке — в 6-минутном тесте, рассчитывали затраты на лечение больных ХОБЛ. Длительность наблюдения составила 6 мес. Результаты исследования показали, что лечение препаратом Спирива ведет к достоверному уменьшению выраженности клинических симптомов ХОБЛ, повышению толерантности к физической нагрузке в течение всего курса терапии. За время лечения у больных достоверно снизились частота обращений за медицинской помощью, длительность периодов временной нетрудоспособности и стационарного лечения. Медицинские затраты на лечение ХОБЛ при использовании Спиривы возрастают за счет его стоимости, но при учете всех затрат (прямых и косвенных) экономическая эффективность составила 32,7 %