Transformation properties of the transverse mass under transverse Lorentz boosts at hadron colliders

The transverse mass of semi-invisibly decaying particles, calculated from the transverse momenta of their decay products, has been used in a broad range of searches and measurements at hadron colliders, such as the LHC. This variable is invariant by construction under Lorentz boosts purely in the longitudinal (beam) direction, thereby minimising sensitivity to fluctuations in the fractions of the proton momentum carried by the colliding partons. In this paper we examine, by contrast, the properties of the transverse mass under boosts with a component also in the transverse plane perpendicular to the beam direction. We show that this variable is invariant under such boosts in cases where the boost is purely transverse and (a) the momenta of the decay products are confined to the transverse plane in the rest frame of the parent particle and/or (b) the transverse momenta of the decay products are perpendicular to the boost direction. We discuss the transformation properties of the transverse mass in the case of combined transverse and longitudinal boosts and identify the criteria under which the transverse mass in the laboratory frame can equal the rest mass of the parent particle, irrespective of its value in the rest frame of the parent.Comment: 7 pages double column, 7 figures, formatted for EPJ

Cultural competency: professional action and South Asian carers

Inequality and exclusion are characteristic of the experience of UK South Asian communities. In health care, community needs are often not addressed by health and social welfare services. An increase in cultural competency is now part of identified policy. The aim of this paper is to examine the extent to which there is evidence of cultural competency amongst professionals concerning South Asian parents caring for a person with cerebral palsy. Semi-structured interviews were conducted with respondents from 19 service organisations. Results are presented on perceptions of service delivery and on the dynamics of service development: evidence is found that inadequate service delivery continues despite professional knowledge that it exists. Conditions necessary for the achievement of cultural competence are discussed. We suggest that service development to meet the needs of South Asian carers must form part of an overall strategy geared to change at different levels within and outside service organisations

Precise role of H pylori in duodenal ulceration

The facts that H pylori infection is commoner in duodenal ulcer (DU) patients than in the normal population, and that eradication results in most cases being cured, have led to the belief that it causes DU. However, early cases of DU are less likely than established ones to be infected. H pylori-negative cases are usually ascribed to specific associated factors such as non-steroidal anti-inflammatory drugs (NSAIDs), Crohn’s disease, and hypergastrinaemia, but even after excluding these, several H pylori-negative cases remain and are particularly common in areas of low prevalence of H pylori infection. Moreover, this incidence of H pylori negative DU is not associated with a fall in overall DU prevalence when compared with countries with a higher H pylori prevalence. In countries with a high H pylori prevalence there are regional differences in DU prevalence, but no evidence of an overall higher prevalence of DU than in countries with a low H pylori prevalence. There is no evidence that virulence factors are predictive of clinical outcome. After healing following eradication of H pylori infection DU can still recur. Medical or surgical measures to reduce acid output can lead to long-term healing despite persistence of H pylori infection. Up to half of cases of acute DU perforation are H pylori negative. These findings lead to the conclusion that H pylori infection does not itself cause DU, but leads to resistance to healing, i.e., chronicity. This conclusion is shown not to be incompatible with the universally high prevalence of DU compared with controls

Evaluating complementary medicine: methodological challenges of randomised controlled trials

Complementary medicine has a different philosophy from conventional medicine, presenting challenges to research methodology. Rigorous evaluation of complementary medicine could provide much needed evidence of its effectiveness. Good design of randomised controlled trials will avoid invalid results and misrepresentation of the holistic essence of complementary medicine. Practitioners need to be recognised as a component in or contributor to complementary treatment. Both specific and non-specific outcome measures with long follow up are needed to adequately encompass the essence of complementary medicine

Helicobacter pylori virulence factors in duodenal ulceration: A primary cause or a secondary infection causing chronicity

Reports from countries with a high prevalence of Helicobacter pylori. (H pylori) infection do not show a proportionately high prevalence of duodenal ulceration, suggesting the possibility that H pylori cannot be a primary cause of duodenal ulceration. It has been mooted that this discrepancy might be explained by variations in the prevalence of virulence factors in different populations. The aim of this paper is to determine whether the published literature gives support to this possibility. The relevant literature was reviewed and analyzed separately for countries with a high and low prevalence of H pylori infection and virulence factors. Although virulent strains of H pylori were significantly more often present in patients with duodenal ulcer than without the disease in countries with a low prevalence of H pylori infection in the population, there was no difference in the prevalence of virulence factors between duodenal ulcer, non - ulcer dyspepsia or normal subjects in many countries, where the prevalence of both H pylori infection and of virulence factors was high. In these countries, the presence of virulence factors was not predictive the clinical outcome. To explain the association between virulence factors and duodenal ulcer in countries where H pylori prevalence is low, only two papers were found that give little support to the usual model proposed, namely that organisms with the virulence factors are more likely than those without them to initiate a duodenal ulcer. We offer an alternative hypothesis that suggests virulence factors are more likely to interfere with the healing of a previously produced ulcer. The presence of virulence factors only correlates with the prevalence of duodenal ulcer in countries where the prevalence of H pylori is low. There is very little evidence that virulence factors initiate duodenal ulceration, but they may be related to failure of the ulcer to heal

Cold Dark Matter and the LHC

The recent determination of the dark matter density in the Universe by the WMAP satellite has brought new attention to the interplay of results from particle physics experiments at accelerators and from cosmology. In this paper we discuss the prospects for finding direct evidence for a candidate dark matter particle at the LHC and the measurements which would be crucial for testing its compatibility with cosmology data.Comment: 33 pages, 15 eps figures, J. Phys. G topical review (documentclass iopart

Measuring the Mass of the Lightest Chargino at the CERN LHC

Results are presented of a feasibility study of techniques for measuring the mass of the lightest chargino at the CERN LHC. These results suggest that for one particular mSUGRA model a statistically significant chargino signal can be identified and the chargino mass reconstructed with a precision of order 11% for of order 100 fb-1 of data.Comment: 6 pages, 5 figures. To appear in the proceedings of the workshop: Les Houches 2003: Physics at TeV Scale Collider

Next generation tyrosine-mutant AAV8 shows high mouse corneal endothelial transduction in vivo [abstract]

Purpose: Recently, point mutations in surface-exposed tyrosine residues have been shown to increase AAV transduction significantly. We examined the efficacy of conventional AAV8 and next generation tyrosine-mutant AAV8 vectors to deliver genes into corneal endothelium in vivo. Methods: The study, which used female C57BL/6 mice, was approved by the institutional animal care and use committee and experiments were performed inaccordance with the tenets of the ARVO statement for the use of animals. Ketamine and Xylazine hydrochloride were administered for anesthesia. Two microliters of AAV8 titer (~1010 vg/ml) was injected into the anterior chamber of the eye from four different clock-positions with the Hamilton Microinjection Syringe System under an operating microscope. Eyes were then washed with water and sponge-dried. Slit lamp microscopy was utilized for clinical eye exam. Stereomicroscopy and immunocytochemistry techniques measured the levels and location of transgene. Delivered-transgene expression was quantified with real-time PCR and western blot analyses. Results: Both, conventional and tyrosine-mutant AAV8 vectors successfully transduced mouse corneal endothelium in vivo. Mutant AAV8 showed significantly higher transgene delivery into corneal endothelium than the conventional AAV8. Injections performed from 12 or 3 o'clock position showed highest targeted transgene delivery into corneal endothelium. Low-to-mild transgene delivery was also detected in the stroma. The tested AAV8 showed no apparent side effects or toxicity. Conclusions: Tested AAV8 vectors are efficient to treat corneal endothelial dystrophies via gene therapy. Future studies will determine optimal doses of conventional and tyrosine-mutant AAV8 vectors to deliver therapeutic genes into corneal endothelial in vivo