1,714 research outputs found
Scattering of a Long Cosmic String by a Rotating Black Hole
The scattering of a straight, infinitely long string by a rotating black hole
is considered. We assume that a string is moving with velocity v and that
initially the string is parallel to the axis of rotation of the black hole. We
demonstrate that as a result of scattering, the string is displaced in the
direction perpendicular to the velocity by an amount kappa(v,b), where b is the
impact parameter. The late-time solution is represented by a kink and
anti-kink, propagating in opposite directions at the speed of light, and
leaving behind them the string in a new ``phase''. We present the results of
the numerical study of the string scattering and their comparison with the
weak-field approximation, valid where the impact parameter is large, b/M >> 1,
and also with the scattering by a non-rotating black hole which was studied in
earlier works.Comment: 27 pages, 14 figures, to be published in Classical and Quantum
Gravit
Highly syntenic and yet divergent: a tale of two Theilerias
The published genomic sequences of the two major host-transforming Theileria species of cattle represent a rich resource of information that has allowed novel bioinformatic and experimental studies into these important apicomplexan parasites. Since their publication in 2005, the genomes of T. annulata and T. parva have been utilised for a diverse range of applications, ranging from candidate antigen discovery to the identification of genetic markers for population analysis. This has led to advancements in the quest for a sub-unit vaccine, while providing a greater understanding of variation among parasite populations in the field. The unique ability of these Theileria species to induce host cell transformation is the subject of considerable scientific interest and the availability of full genomic sequences has provided new insights into this area of research. This article reviews the data underlying published comparative analyses, focussing on the general features of gene expression, the major Tpr/Tar multi-copy gene family and a re-examination of the predicted macroschizont secretome. Codon usage between the Theileria species is reviewed in detail, as this underpins ongoing comparative studies investigating selection at the intra- and inter-species level. The TashAT/TpshAT family of genes, conserved between T. annulata and T. parva, encodes products targeted to the host nucleus and has been implicated in contributing to the transformed bovine phenotype. Species-specific expansion and diversification at this critical locus is discussed with reference to the availability, in the near future, of genomic datasets which are based on non-transforming Theileria species
Instability of a membrane intersecting a black hole
The stability of a Nambu-Goto membrane at the equatorial plane of the
Reissner-Nordstr{\o}m-de Sitter spacetime is studied. The covariant
perturbation formalism is applied to study the behavior of the perturbation of
the membrane. The perturbation equation is solved numerically. It is shown that
a membrane intersecting a charged black hole, including extremely charged one,
is unstable and that the positive cosmological constant strengthens the
instability.Comment: 12 pages, 3 figures, to be published in Physical Review
Thick domain walls around a black hole
We discuss the gravitationally interacting system of a thick domain wall and
a black hole. We numerically solve the scalar field equation in the
Schwarzschild spacetime and obtain a sequence of static axi-symmetric solutions
representing thick domain walls. We find that, for the walls near the horizon,
the Nambu--Goto approximation is no longer valid.Comment: 18 pages, 11 figures, one reference adde
Rigidly Rotating Strings in Stationary Spacetimes
In this paper we study the motion of a rigidly rotating Nambu-Goto test
string in a stationary axisymmetric background spacetime. As special examples
we consider the rigid rotation of strings in flat spacetime, where explicit
analytic solutions can be obtained, and in the Kerr spacetime where we find an
interesting new family of test string solutions. We present a detailed
classification of these solutions in the Kerr background.Comment: 19 pages, Latex, 9 figures, revised for publication in Classical and
Quantum Gravit
Thick Domain Walls and Charged Dilaton Black Holes
We study a black hole domain wall system in dilaton gravity which is the
low-energy limit of the superstring theory. We solve numerically equations of
motion for real self-interacting scalar field and justify the existence of
static axisymmetric field configuration representing the thick domain wall in
the background of a charged dilaton black hole. It was also confirmed that the
extreme dilaton black hole always expelled the domain wall.Comment: 10 pages, 8 figures; to be published in Phys. Rev. D1
Reissner-Nordstrom Black Holes and Thick Domain Walls
We solve numerically equations of motion for real self-interacting scalar
fields in the background of Reissner-Nordstrom black hole and obtained a
sequence of static axisymmetric solutions representing thick domain walls
charged black hole systems. In the case of extremal Reissner-Nordstrom black
hole solution we find that there is a parameter depending on the black hole
mass and the width of the domain wall which constitutes the upper limit for the
expulsion to occur.Comment: 18 pages, 10 figures, accepted for Phys. Rev.
Effect of ospemifene on moderate or severe symptoms of vulvar and vaginal atrophy.
Objectives To determine whether assessment of all moderate-to-severe symptoms at baseline gives a more accurate evaluation of the treatment effect of ospemifene in vulvovaginal atrophy (VVA) than the most bothersome symptom (MBS) approach. Methods Data were pooled from two pivotal phase-III clinical trials evaluating the efficacy and safety of oral ospemifene 60 mg/day for the treatment of symptoms of VVA (n = 1463 subjects). Symptoms of vaginal dryness, dyspareunia, and vaginal and/or vulvar irritation/itching reported as moderate or severe at baseline were evaluated. Clinically relevant differences between ospemifene and placebo were analyzed using a four-point severity scoring system and presented as improvement, substantial improvement, or relief. Results Subjects in these studies reported statistically significant improvement, substantial improvement, and relief for vaginal dryness (p \u3c 0.00001), dyspareunia (p \u3c 0.001) and statistically significant improvement and relief for vaginal and/or vulvar irritation/itching (p \u3c 0.01) from baseline to week 12 with ospemifene compared with placebo. A similar trend was observed for women who reported substantial improvement of vaginal and/or vulvar irritation/itching. Conclusions For drug registration purposes, the use of the MBS model is appealing because of its simplicity and ease of scientific validation. However, the MBS model may underestimate the total magnitude of the clinical benefit of ospemifene treatment for symptomatic women suffering from VVA
Effect of ospemifene on moderate or severe symptoms of vulvar and vaginal atrophy.
Objectives To determine whether assessment of all moderate-to-severe symptoms at baseline gives a more accurate evaluation of the treatment effect of ospemifene in vulvovaginal atrophy (VVA) than the most bothersome symptom (MBS) approach. Methods Data were pooled from two pivotal phase-III clinical trials evaluating the efficacy and safety of oral ospemifene 60 mg/day for the treatment of symptoms of VVA (n = 1463 subjects). Symptoms of vaginal dryness, dyspareunia, and vaginal and/or vulvar irritation/itching reported as moderate or severe at baseline were evaluated. Clinically relevant differences between ospemifene and placebo were analyzed using a four-point severity scoring system and presented as improvement, substantial improvement, or relief. Results Subjects in these studies reported statistically significant improvement, substantial improvement, and relief for vaginal dryness (p \u3c 0.00001), dyspareunia (p \u3c 0.001) and statistically significant improvement and relief for vaginal and/or vulvar irritation/itching (p \u3c 0.01) from baseline to week 12 with ospemifene compared with placebo. A similar trend was observed for women who reported substantial improvement of vaginal and/or vulvar irritation/itching. Conclusions For drug registration purposes, the use of the MBS model is appealing because of its simplicity and ease of scientific validation. However, the MBS model may underestimate the total magnitude of the clinical benefit of ospemifene treatment for symptomatic women suffering from VVA
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