Heavy ion beam lifetimes at relativistic and ultrarelativistic colliders

The effects of higher order corrections in ultra-relativistic nuclear collisions are considered. It is found that higher order contributions are small at low energy, large at intermediate energy and small again at very high energy. An explanation for this effect is given. This means that the Weizsacker-Williams formula is a good approximation to use in calculating cross sections and beam lifetimes at energies relevant to RHIC and LHC.Comment: 10 pages, 2 tables, 4 figure

Graviton Production in Relativistic Heavy-Ion Collisions

We study the feasibility of producing the graviton of the novel Kaluza-Klein theory in which there are d large compact dimensions in addition to the 4 dimensions of Minkowski spacetime. We calculate the cross section for producing such a graviton in nucleus-nucleus collisions via t-channel photon-photon fusion using the semiclassical Weizsacker-Williams method and show that it can exceed the cross section for graviton production in electron-positron scattering by several orders of magnitude.Comment: 10 pages, 3 figures, accepted for publication in Physical Review

Investigation of the contractile and regulatory proteins in malignant hyperthermia and normal skeletal muscle

Malignant hyperthermia/hyperpyrexia (MH) is a serious human skeletal muscle disorder that manifests itself during general anaesthesia. Currently, the most reliable method of diagnosing this disease is the in-vitro contracture test (IVCT). This procedure is both highly invasive for the patient and expensive to perform. The skinned muscle fibre technique is less invasive, and could possibly be used as an alternative diagnostic test for MH. In this study, skeletal muscle samples were obtained from B adults (age 23-54 years) undergoing elective surgery at Royal Perth Hospital. Six patients were diagnosed as normal (controls) and two equivocal for MH (MHE). Using the skinned muscle fibre technique (with exogenous Ca2+ and Sr2+), individual muscle fibre segments (10 from each biopsy) were tested for differences in their contractile and regulatory proteins, and the generated force per cross-sectional area (F/CSA). The results indicated that the contractile and regulatory proteins of the MHE fibres displayed altered functionality in comparison to the control fibres. The Type I MHE fibres displayed greater sensitivity to Sr+2+ (82%), whereas the Mixed MHE fibres displayed greater sensitivity to Ca2+ (90%). However, the F/CSA generated by the MHE fibres were overall less than that of the control fibres (43%), denoting statistical insignificance

Models of discretized moduli spaces, cohomological field theories, and Gaussian means

We prove combinatorially the explicit relation between genus filtrated $s$-loop means of the Gaussian matrix model and terms of the genus expansion of the Kontsevich--Penner matrix model (KPMM). The latter is the generating function for volumes of discretized (open) moduli spaces $M_{g,s}^{\mathrm{disc}}$ given by $N_{g,s}(P_1,\dots,P_s)$ for $(P_1,\dots,P_s)\in{\mathbb Z}_+^s$. This generating function therefore enjoys the topological recursion, and we prove that it is simultaneously the generating function for ancestor invariants of a cohomological field theory thus enjoying the Givental decomposition. We use another Givental-type decomposition obtained for this model by the second authors in 1995 in terms of special times related to the discretisation of moduli spaces thus representing its asymptotic expansion terms (and therefore those of the Gaussian means) as finite sums over graphs weighted by lower-order monomials in times thus giving another proof of (quasi)polynomiality of the discrete volumes. As an application, we find the coefficients in the first subleading order for ${\mathcal M}_{g,1}$ in two ways: using the refined Harer--Zagier recursion and by exploiting the above Givental-type transformation. We put forward the conjecture that the above graph expansions can be used for probing the reduction structure of the Delgne--Mumford compactification $\overline{\mathcal M}_{g,s}$ of moduli spaces of punctured Riemann surfaces.Comment: 36 pages in LaTex, 6 LaTex figure

Immunity to Murine Sarcoma Virus Induced Tumors. III. Analysis of the Cell Populations Involved in Protection from Lethal Tumour Progression of Sublethally Irradiated, MSV Inoculated, Mice

A comparison was made between the cells responsible for demonstrable activity against MSV antigens, using both in vivo and in vitro assays. Similar cells (in terms of size and sensitivity to anti-theta serum) were detected in both assays. However, while lymphoid cells from animals at all stages post-MSV infection were active in protecting irradiated mice from the lethal effect of induction of MSV sarcomata, cells from animals at early stages post-MSV infection (when the tumour was in a progressive phase of growth) were not active in the in vitro assay. By manipulation of the in vivo assay conditions a situation was observed in which cells from “progressor animals” were able to suppress both the in vitro and in vivo activity of regressor lymphoid cells. The potential physiological role of this cell type is disussed

Upstream toward the “DRiP”-ing Source of the MHC Class I Pathway

MHC class I binding peptides are generated via cytosolic degradation of a previously undefined substrate. In this issue of Immunity, Kunisawa and Shastri (2006) isolate pre-degradation polypeptide intermediates bound to a cytosolic chaperone

Hyperbolic calorons, monopoles, and instantons

We construct families of SO(3)-symmetric charge 1 instantons and calorons on the space H^3 x R. We show how the calorons include instantons and hyperbolic monopoles as limiting cases. We show how Euclidean calorons are the flat space limit of this family.Comment: 11 pages, no figures 1 reference added Published version available at: http://www.springerlink.com/content/k0j4815u54303450

The ubiquitin-proteasome pathway in cancer.

Degradation by the 26S proteasome of specific proteins that have been targeted by the ubiquitin pathway is the major intracellular non-lysosomal proteolytic mechanism and is involved in a broad range of processes, such as cell cycle progression, antigen presentation and control of gene expression. Recent work, reviewed here, has shown that this pathway is often the target of cancer-related deregulation and can underlie processes, such as oncogenic transformation, tumour progression, escape from immune surveillance and drug resistance

Figurative language comprehension in individuals with autism spectrum disorder: A meta-analytic review

We present a meta-analysis of studies that compare figurative language comprehension in individuals with autism spectrum disorder and in typically developing controls who were matched based on chronological age or/and language ability. A total of 41 studies and 45 independent effect sizes were included based on predetermined inclusion criteria. Group matching strategy, age, types of figurative language, and cross-linguistic differences were examined as predictors that might explain heterogeneity in effect sizes. Overall, individuals with autism spectrum disorder showed poorer comprehension of figurative language than their typically developing peers (Hedges’ g = –0.57). A meta-regression analysis showed that group matching strategy and types of figurative language were significantly related to differences in effect sizes, whereas chronological age and cross-linguistic differences were not. Differences between the autism spectrum disorder and typically developing groups were small and nonsignificant when the groups were matched based on the language ability. Metaphors were more difficult to comprehend for individuals with autism spectrum disorder compared with typically developing controls than were irony and sarcasm. Our findings highlight the critical role of core language skills in figurative language comprehension. Interventions and educational programmes designed to improve social communication skills in individuals with autism spectrum disorder may beneficially target core language skills in addition to social skills