Concept for improved vacuum pressure measuring device

To measure vacuum pressures in the range of 5 times 10 to the minus 7 to 5 times 10 to the minus 16, a semiconductor resistor composed of sintered zinc oxide is used. Through the effect of surface absorbed gases on the resistance of the semiconductor material, very low pressures are measured

Anatomy of a Bounce

Holographic considerations are used in the scrutiny of a special class of brane-world cosmologies. Inherently to this class, the brane typically bounces, at a finite size, as a consequence of a charged black hole in the bulk. Whereas a prior treatment [hep-th/0301010] emphasized a brane that is void of standard-model matter, the analysis is now extended to include an intrinsic (radiation-dominated) matter source. An interesting feature of this generalized model is that a bounce is no longer guaranteed but, rather, depends on the initial conditions. Ultimately, we demonstrate that compliance with an appropriate holographic bound is a sufficient prerequisite for a bounce to occur.Comment: 14 pages, Revtex; (v2) minor revisions; (v3) reference adde

Graviton n-point functions for UV-complete theories in Anti-de Sitter space

We calculate graviton n-point functions in an anti-de Sitter black brane background for effective gravity theories whose linearized equations of motion have at most two time derivatives. We compare the n-point functions in Einstein gravity to those in theories whose leading correction is quadratic in the Riemann tensor. The comparison is made for any number of gravitons and for all physical graviton modes in a kinematic region for which the leading correction can significantly modify the Einstein result. We find that the n-point functions of Einstein gravity depend on at most a single angle, whereas those of the corrected theories may depend on two angles. For the four-point functions, Einstein gravity exhibits linear dependence on the Mandelstam variable s versus a quadratic dependence on s for the corrected theory.Comment: 29 page

Thermal Fluctuations and Black Hole Entropy

In this paper, we consider the effect of thermal fluctuations on the entropy of both neutral and charged black holes. We emphasize the distinction between fixed and fluctuating charge systems; using a canonical ensemble to describe the former and a grand canonical ensemble to study the latter. Our novel approach is based on the philosophy that the black hole quantum spectrum is an essential component in any such calculation. For definiteness, we employ a uniformly spaced area spectrum, which has been advocated by Bekenstein and others in the literature. The generic results are applied to some specific models; in particular, various limiting cases of an (arbitrary-dimensional) AdS-Reissner-Nordstrom black hole. We find that the leading-order quantum correction to the entropy can consistently be expressed as the logarithm of the classical quantity. For a small AdS curvature parameter and zero net charge, it is shown that, independent of the dimension, the logarithmic prefactor is +1/2 when the charge is fixed but +1 when the charge is fluctuating.We also demonstrate that, in the grand canonical framework, the fluctuations in the charge are large, $\Delta Q\sim\Delta A\sim S_{BH}^{1/2}$, even when $=0$. A further implication of this framework is that an asymptotically flat, non-extremal black hole can never achieve a state of thermal equilibrium.Comment: 25 pages, Revtex; references added and corrected, and some minor change

Entropy Corrections for Schwarzschild and Reissner-Nordstr\"om Black Holes

Schwarzschild black hole being thermodynamically unstable, corrections to its entropy due to small thermal fluctuations cannot be computed. However, a thermodynamically stable Schwarzschild solution can be obtained within a cavity of any finite radius by immersing it in an isothermal bath. For these boundary conditions, classically there are either two black hole solutions or no solution. In the former case, the larger mass solution has a positive specific heat and hence is locally thermodynamically stable. We find that the entropy of this black hole, including first order fluctuation corrections is given by: {\cal S} = S_{BH} - \ln[\f{3}{R} (S_{BH}/4\p)^{1/2} -2]^{-1} + (1/2) \ln(4\p), where $S_{BH}=A/4$ is its Bekenstein-Hawking entropy and $R$ is the radius of the cavity. We extend our results to four dimensional Reissner-Nordstr\"om black holes, for which the corresponding expression is: {\cal S} = S_{BH} - \f{1}{2} \ln [ {(S_{BH}/\p R^2) ({3S_{BH}}/{\p R^2} - 2\sqrt{{S_{BH}}/{\p R^2 -\a^2}}) \le(\sqrt{{S_{BH}}/{\p R^2}} - \a^2 \ri)}/ {\le({S_{BH}}/{\p R^2} -\a^2 \ri)^2} ]^{-1} +(1/2)\ln(4\p). Finally, we generalise the stability analysis to Reissner-Nordstr\"om black holes in arbitrary spacetime dimensions, and compute their leading order entropy corrections. In contrast to previously studied examples, we find that the entropy corrections in these cases have a different character.Comment: 6 pages, Revtex. References added, minor changes. Version to appear in Class. Quant. Gra

Of Bounces, Branes and Bounds

Some recent studies have considered a Randall-Sundrum-like brane world evolving in the background of an anti-de Sitter Reissner-Nordstrom black hole. For this scenario, it has been shown that, when the bulk charge is non-vanishing, a singularity-free ``bounce'' universe will always be obtained. However, for the physically relevant case of a de Sitter brane world, we have recently argued that, from a holographic (c-theorem) perspective, such brane worlds may not be physically viable. In the current paper, we reconsider the validity of such models by appealing to the so-called ``causal entropy bound''. In this framework, a paradoxical outcome is obtained: these brane worlds are indeed holographically viable, provided that the bulk charge is not too small. We go on to argue that this new finding is likely the more reliable one.Comment: 15 pages, Revtex; references added and very minor change

Bouncing cosmological solutions and their stability

In the present paper we consider the bouncing braneworld scenario, in which the bulk is given by a five-dimensional charged AdS black hole spacetime with matter field confined in a $D_3$ brane. Then, we study the stability of solutions with respect to homogeneous and isotropic perturbations. Specifically, the AdS black hole with zero ADM mass and charge, and open horizon is an attractor, while the charged AdS black hole with zero ADM mass and flat horizon, is a repeller.Comment: 9 pages, 1 figur

A Study of RO5217790 (HPV Targeted Immunotherapy) in Patients With High Grade Cervical Intraepithelial Neoplasia Associated With High Risk HPV Infection

Comparative Medicine - OneHealth and Comparative Medicine Poster SessionThis is a randomized, double blind, placebo controlled, parallel group multicenter study in women with biopsy confirmed Grade 2 or Grade 3 cervical intraepithelial neoplasia (CIN). Two hundred patients will be enrolled and randomized in a 2: 1 ratio of RO5217790: placebo. They will be stratified on the basis of their HPV genotyping with stratum 1 consisting of those women with HPV 16 single infection and stratum 2 consisting of those with single or multiple infections with other high risk genotypes. Three injections of RO5217790 (5 x 107pfu) will be administered subcutaneously, each one week apart. Interim colposcopy, cytology and HPV assessments will be performed at Month 3. All patients will undergo conization at Month 6. The primary endpoint is histologic response at Month 6 in HPV 16 single infected patients, as assessed by central pathology review. The secondary endpoints include histologic response in all CIN2/3 patients enrolled regardless of genotype, viral clearance, safety, and immune response (cellular and humoral). After the Month 6 conization, the study will be unblinded and patients will undergo follow-up for an additional 2 years for efficacy and safety. This includes visits at Months 12, 18, 24 and 30 to assess histologic relapse/recurrence and viral re-infection as well as reporting of any serious adverse events. An interim analysis will be conducted when a minimum of 80 patients (at least 20 of whom have single infection with HPV 16 and 20 of whom have infection with HPV 16 plus HPV 16 related genotypes) have undergone conization. NCT0102234