A Study of Phase Transition in Black Hole Thermodynamics

This paper deals with five-dimensional black hole solutions in (a) Einstein-Maxwell-Gauss-Bonnet theory with a cosmological constant and (b)Einstein-Yang-Mills-Gauss-Bonnet theory for spherically symmetric space time. In both the cases the possibility of phase transition is examined and it is analyzed whether the phase transition is a Hawking-Page type phase transition or not.Comment: 16 figure

Precision neutron interferometric measurements of the n-p, n-d, and n-3He zero-energy coherent neutron scattering amplitudes

We have performed high precision measurements of the zero-energy neutron scattering amplitudes of gas phase molecular hydrogen, deuterium, and $^{3}$He using neutron interferometry. We find $b_{\mathit{np}}=(-3.7384 \pm 0.0020)$ fm\cite{Schoen03}, $b_{\mathit{nd}}=(6.6649 \pm 0.0040)$ fm\cite{Black03,Schoen03}, and $b_{n^{3}\textrm{He}} = (5.8572 \pm 0.0072)$ fm\cite{Huffman04}. When combined with the previous world data, properly corrected for small multiple scattering, radiative corrections, and local field effects from the theory of neutron optics and combined by the prescriptions of the Particle Data Group, the zero-energy scattering amplitudes are: $b_{\mathit{np}}=(-3.7389 \pm 0.0010)$ fm, $b_{\mathit{nd}}=(6.6683 \pm 0.0030)$ fm, and $b_{n^{3}\textrm{He}} = (5.853 \pm .007)$ fm. The precision of these measurements is now high enough to severely constrain NN few-body models. The n-d and n-$^{3}$He coherent neutron scattering amplitudes are both now in disagreement with the best current theories. The new values can be used as input for precision calculations of few body processes. This precision data is sensitive to small effects such as nuclear three-body forces, charge-symmetry breaking in the strong interaction, and residual electromagnetic effects not yet fully included in current models.Comment: 6 pages, 4 figures, submitted to Physica B as part of the Festschrift honouring Samuel A. Werner at the International Conference on Neutron Scattering 200

Entropy of Lovelock Black Holes

A general formula for the entropy of stationary black holes in Lovelock gravity theories is obtained by integrating the first law of black hole mechanics, which is derived by Hamiltonian methods. The entropy is not simply one quarter of the surface area of the horizon, but also includes a sum of intrinsic curvature invariants integrated over a cross section of the horizon.Comment: 15 pages, plain Latex, NSF-ITP-93-4

Overview of the SME: Implications and Phenomenology of Lorentz Violation

The Standard Model Extension (SME) provides the most general observer-independent field theoretical framework for investigations of Lorentz violation. The SME lagrangian by definition contains all Lorentz-violating interaction terms that can be written as observer scalars and that involve particle fields in the Standard Model and gravitational fields in a generalized theory of gravity. This includes all possible terms that could arise from a process of spontaneous Lorentz violation in the context of a more fundamental theory, as well as terms that explicitly break Lorentz symmetry. An overview of the SME is presented, including its motivations and construction. Some of the theoretical issues arising in the case of spontaneous Lorentz violation are discussed, including the question of what happens to the Nambu-Goldstone modes when Lorentz symmetry is spontaneously violated and whether a Higgs mechanism can occur. A minimal version of the SME in flat Minkowski spacetime that maintains gauge invariance and power-counting renormalizability is used to search for leading-order signals of Lorentz violation. Recent Lorentz tests in QED systems are examined, including experiments with photons, particle and atomic experiments, proposed experiments in space and experiments with a spin-polarized torsion pendulum.Comment: 40 pages, Talk presented at Special Relativity: Will it Survive the Next 100 Years? Potsdam, Germany, February, 200

Immune or genetic-mediated disruption of CASPR2 causes pain hypersensitivity due to enhanced primary afferent excitability

Human autoantibodies to contactin-associated protein-like 2 (CASPR2) are often associated with neuropathic pain, and CASPR2 mutations have been linked to autism spectrum disorders, in which sensory dysfunction is increasingly recognized. Human CASPR2 autoantibodies, when injected into mice, were peripherally restricted and resulted in mechanical pain-related hypersensitivity in the absence of neural injury. We therefore investigated the mechanism by which CASPR2 modulates nociceptive function. Mice lacking CASPR2 (Cntnap2(-/-)) demonstrated enhanced pain-related hypersensitivity to noxious mechanical stimuli, heat, and algogens. Both primary afferent excitability and subsequent nociceptive transmission within the dorsal horn were increased in Cntnap2(-/-) mice. Either immune or genetic-mediated ablation of CASPR2 enhanced the excitability of DRG neurons in a cell-autonomous fashion through regulation of Kv1 channel expression at the soma membrane. This is the first example of passive transfer of an autoimmune peripheral neuropathic pain disorder and demonstrates that CASPR2 has a key role in regulating cell-intrinsic dorsal root ganglion (DRG) neuron excitability

A study of a mutant elongation factor properties of E. coli HAK88 and its mutant elongation factor Tu

The E. coli chromosome contains two genes for elongation factor Tu, tufA (near the fusidic acid resistance marker) and tufB (near the rifampicin resistance marker). It has been discovered that the mutant E. coli K12 strain HAK88 bears a mutation in the tufB gene, which leads to the synthesis of a protein of increased acidity. To determine whether the mutation has altered the protein's function in peptide chain elongation, we have compared the reactivities of normal tufA EF-Tu and mutant tufB EF-Tu (purified together from HAK88) with the components of the AA-tRNA binding cycle. Normal tufA EF-Tu and mutant tufB EF-Tu are indistinguishable in their affinities for GDP, EF-Ts, and phe-tRNA, and differ only slightly in their affinities for ribosomes. Coupled with the results of a separate study showing the similarity of the normal tufA and tufB gene products, these experiments demonstrate that the mutation has not altered the function of tufB EF-Tu in peptide chain elongation. Contrary to the original report (Kuwano et al., 1974; J. Mol. Biol. 86 , 689–698) the HAK88 strains we have examined no longer possess a temperature-sensitive EF-Ts. The growth rates of HAK88 strains resemble the parent HAK8 strain in their lack of tRNA dependence but unlike HAK8 show varying degrees of temperature sensitivity. We conclude that HAK88 contains a physically altered but functionally intact tufB EF-Tu. The mutation in tufB should be valuable for studying in vivo the control of expression of the genes for EF-Tu.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47543/1/438_2004_Article_BF00401747.pd

Altered Cognitive Function in Men Treated for Prostate Cancer with LHRH Analogues and Cyproterone Acetate: A Randomised Controlled Trial

Objective. Luteinising hormone releasing hormone (LHRH) analogues have been associated with memory impairments in women using these drugs for gynaecological conditions. This is the first systematic investigation of the cognitive effects of LHRH analogues in male patients. Methods. 82 men with non-localised prostate cancer were randomly assigned to receive continuous leuprorelin (LHRH analogue), goserelin (LHRH analogue), cyproterone acetate (steroidal antiandrogen) or close clinical monitoring. These patients underwent cognitive assessments at baseline and before commencement of treatment (77) then 6 months later (65). Results. Compared with baseline assessments, men administered androgen suppression monotherapy performed worse in 2/12 tests of attention and memory. 24/50 men randomised to active treatment and assessed 6 months later demonstrated clinically significant decline in one or more cognitive tests but not one patient randomised to close monitoring showed a decline in any test performance. Conclusion. Pharmacological androgen suppression monotherapy for prostate cancer may be associated with impaired memory, attention and executive functions

MMN and Differential Waveform

A mismatch negativity response (MMN) and a new differential waveform were derived in an effort to evaluate a neural refractory or recovery effect in adult listeners. The MMN was elicited using oddball test runs in which the standard and deviant stimuli differed in frequency. To derive the differential waveform, the same standard and deviant stimuli were presented alone. MMN responses were obtained by subtracting the averaged responses to standards from the deviants. The differential waveforms were obtained by subtracting the averaged responses to standards presented alone from deviants presented alone. Scalp topography for the MMN and differential waveforms were similar. A significant (p < .05) positive and negative correlation was found between the earlier and later components of the bimodal MMN and the N1 and P2 component of the differential waveform, respectively. Further, N1 and P2 of the differential waveform were significant (p < .05) predictor variables of early and late peak amplitudes of the MMN. These results suggest that refractory effects may overlay/modify the morphology of the MMN waveform