A method to measure vacuum birefringence at FCC-ee

It is well-known that the Heisenberg-Euler-Schwinger effective Lagrangian predicts that a vacuum with a strong static electromagnetic field turns birefringent. We propose a scheme that can be implemented at the planned FCC-ee, to measure the nonlinear effect of vacuum birefringence in electrodynamics arising from QED corrections. Our scheme employs a pulsed laser to create Compton backscattered photons off a high energy electron beam, with the FCC-ee as a particularly interesting example. These photons will pass through a strong static magnetic field, which changes the state of polarization of the radiation - an effect proportional to the photon energy. This change will be measured by the use of an aligned single-crystal, where a large difference in the pair production cross-sections can be achieved. In the proposed experimental setup the birefringence effect gives rise to a difference in the number of pairs created in the analyzing crystal, stemming from the fact that the initial laser light has a varying state of polarization, achieved with a rotating quarter wave plate. Evidence for the vacuum birefringent effect will be seen as a distinct peak in the Fourier transform spectrum of the pair-production rate signal. This tell-tale signal can be significantly above background with only few hours of measurement, in particular at high energies.Comment: Presented by UIU at the International Symposium on "New Horizons in Fundamental Physics: From Neutrons Nuclei via Superheavy Elements and Supercritical Fields to Neutron Stars and Cosmic Rays," held to honor Walter Greiner on his 80th birthday at Makutsi Safari Farm, South Africa, November 23-29, 201

Escape rate and Hausdorff measure for entire functions

The escaping set of an entire function is the set of points that tend to infinity under iteration. We consider subsets of the escaping set defined in terms of escape rates and obtain upper and lower bounds for the Hausdorff measure of these sets with respect to certain gauge functions.Comment: 24 pages; some errors corrected, proof of Theorem 2 shortene

Improved maximum likelihood estimators in a heteroskedastic errors-in-variables model

This paper develops a bias correction scheme for a multivariate heteroskedastic errors-in-variables model. The applicability of this model is justified in areas such as astrophysics, epidemiology and analytical chemistry, where the variables are subject to measurement errors and the variances vary with the observations. We conduct Monte Carlo simulations to investigate the performance of the corrected estimators. The numerical results show that the bias correction scheme yields nearly unbiased estimates. We also give an application to a real data set.Comment: 12 pages. Statistical Paper

Renormalization-group approach to superconductivity: from weak to strong electron-phonon coupling

We present the numerical solution of the renormalization group (RG) equations derived in Ref. [1], for the problem of superconductivity in the presence of both electron-electron and electron-phonon coupling at zero temperature. We study the instability of a Fermi liquid to a superconductor and the RG flow of the couplings in presence of retardation effects and the crossover from weak to strong coupling. We show that our numerical results provide an ansatz for the analytic solution of the problem in the asymptotic limits of weak and strong coupling.Comment: 8 pages, 3 figures, conference proceedings for the Electron Correlations and Materials Properties, in Kos, Greece, July 5-9, 200

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Diversity in the organization of elastin bundles and intramembranous muscles in bat wings

Unlike birds and insects, bats fly with wings composed of thin skin that envelops the bones of the forelimb and spans the area between the limbs, digits, and sometimes the tail. This skin is complex and unusual; it is thinner than typical mammalian skin and contains organized bundles of elastin and embedded skeletal muscles. These elements are likely responsible for controlling the shape of the wing during flight and contributing to the aerodynamic capabilities of bats. We examined the arrangement of two macroscopic architectural elements in bat wings, elastin bundles and wing membrane muscles, to assess the diversity in bat wing skin morphology. We characterized the plagiopatagium and dactylopatagium of 130 species from 17 families of bats using cross‐polarized light imaging. This method revealed structures with distinctive relative birefringence, heterogeneity of birefringence, variation in size, and degree of branching. We used previously published anatomical studies and tissue histology to identify birefringent structures, and we analyzed their architecture across taxa. Elastin bundles, muscles, neurovasculature, and collagenous fibers are present in all species. Elastin bundles are oriented in a predominantly spanwise or proximodistal direction, and there are five characteristic muscle arrays that occur within the plagiopatagium, far more muscle than typically recognized. These results inform recent functional studies of wing membrane architecture, support the functional hypothesis that elastin bundles aid wing folding and unfolding, and further suggest that all bats may use these architectural elements for flight. All species also possess numerous muscles within the wing membrane, but the architecture of muscle arrays within the plagiopatagium varies among families. To facilitate present and future discussion of these muscle arrays, we refine wing membrane muscle nomenclature in a manner that reflects this morphological diversity. The architecture of the constituents of the skin of the wing likely plays a key role in shaping wings during flight

The Association between Vitamin D Receptor Expression and Prolonged Overall Survival in Breast Cancer.

Summary In this study, we analyzed vitamin D receptor (VDR) expression and survival in a breast cancer patient cohort of 82 breast cancer patients. Immunohistochemical analysis was possible in 91.5% of the patients (75/82). Staining was evaluated using the semi-quantitative assay according to Remmele and Stegner (immunoreactivity score [IRS]). IRS 0–1 was negative/very low, IRS 2–4 was moderate to high, and IRS 6–12 was high. Statistical analysis was performed by Spearman’s correlation test (p<0.05 significant). Overall survival was analyzed using Kaplan-Meier estimations. Only 6 patients had a negative IRS. Moderate IRS values were present in 20 patients. Most of the patients had a high IRS (49). For survival analysis, data were dichotomized (IRS 0–4: negative to moderate and IRS 6–12: high VDR expression). In univariate analysis, VDR expression showed significant differences in progression-free survival (PFS) and overall survival (OS). Patients with high IRS scores showed significantly better PFS and OS than patients with moderate/negative IRS scores for VDR expression. Tumor size was significantly correlated to PFS. When analyzed separately, the three different IRS groups showed significant differences in VDR expression. The present data suggest that VDR expression in breast cancer tissue may be of clinical significance, and the results provide evidence that VDR may be a factor with prognostic relevance. (J Histochem Cytochem 60:121–129, 2012). Keywords: breast cancer, vitamin D receptor, immunohistochemistry, prognosi

Estimates of outcrossing rates in Moringa oleifera using Amplified fragment length polymorphism (AFLP)

The mating system in plant populations is influenced by genetic and environmental factors. Proper estimates of the outcrosing rates are often required for planning breeding programmes, conservation and management of tropical trees. However, although Moringa oleifera is adapted to a mixed mating system, the proportion of selfing has not been previously estimated. The current work therefore, shows the use of AFLP markers in a mating system study of M. oleifera seed orchard. Data revealed a mixed mating system with a multilocus outcrossing rate (tm) of 0.74. It further demonstrated that AFLP markers, though dominant with a lower information content than co-dominant markers are adequate for the study of the mating system in plant populations. The 26% selfing observed in M. oleifera can lead to overestimation of the proportion of additive genetic variance and appropriate adjustments are therefore required. However, the presence of selfing as well as early sexual maturity (6 months to 1 year) in M. oleifera provides an opportunity for developing inbred lines and hybridisation. Additionally, in designing M. oleifera seed orchards, randomisation and minimum distance between related individuals need to be worked out to maximise cross-fertilisation among unrelated clones and minimise selfing or mating among related ramets. Key words: Moringa oleifera, mating system, outcrossing rates, amplified fragment length polymorphism. African Journal of Biotechnology Vol.3(2) 2004: 146-15

A randomised controlled feasibility trial of the Graded Repetitive Arm Strengthening Programme delivered to survivors of stroke at home

BACKGROUND/AIMS: This randomised controlled feasibility trial evaluated the recruitment, engagement and effect of the Graded Repetitive Arm Strengthening Programme in a community rehabilitation setting in London, UK. METHODS: A parallel design was used to ascertain the effect of the Graded Repetitive Arm Strengthening Programme plus standard care compared to standard care only over four weeks. Eleven participants were randomised using permuted blocks randomisation following discharge, with six participants allocated to the Graded Repetitive Arm Strengthening Programme (study) group and five to the standard care (control) group. The primary outcome was the Wolf Motor Function Test. Secondary outcomes were the Motor Activity Log and grip strength. RESULTS: A total of five participants in each group were analysed as one person withdrew from the study group. Participants in the study group gave more time to supplementing their exercise time independently (160% more vs 42% more). Most Wolf Motor Function Test tasks' time and function data showed a small difference in favour of the Graded Repetitive Arm Strengthening Programme. Results were re-examined using a Bayesian structural equation model to quantify changes in the underlying impairment. This showed significant differences: 40% faster task completion (P<0.001, 95% confidence level [CI] 30–49%), mean improvement of 0.54 on the five-point functional ability score (P<0.001, 95% CI 0.39–0.68), odds ratio of 0.05 for non-completion of task (P<0.001, 95% CI 0.02–0.14). CONCLUSIONS: This study has shown that implementing the Graded Repetitive Arm Strengthening Programme is feasible and may have a greater effect on outcomes when delivered as part of care in a community rehabilitation setting. The analysis of the Wolf Motor Function Test was also critiqued

Functional outcome of patients with spinal cord injury: rehabilitation outcome study

Objective: To increase our knowledge of neurological recovery and functional outcome of patients with spinal cord injuries in order to make more successful rehabilitation programmes based on realistic goals.Design: Descriptive analysis of data gathered in an information system.Setting: Rehabilitation centre in The Netherlands with special department for patients with spinal cord injuries.Subjects: Fifty-five patients with traumatic spinal cord lesions admitted to the rehabilitation centre from 1988 to 1994. Main outcome measures: The functional improvement was presented in terms of progress in independence in nine daily activity skills. Independence was rated on a four-point scale.Results: From admission to discharge, lesions in 100% of patients with tetraplegia and 96% of patients with paraplegia remained complete. Significant progress in independence was made in self-care, ambulation and bladder and bowel care. Differences were found in the extent of functional improvement between subgroups of patients with different levels and extent of lesion. Contrary to expectations based on theoretical models, patients with complete paraplegia did not achieve maximal independence in self-care. Independent walking was only attained by patients with incomplete lesions. Regarding outcome of bladder and bowel care, poor results were found, especially the independence in defaecation and toilet transfers.Conclusions: The results of this study provided more insight into the functional outcome of a group of patients with traumatic spinal cord injury. More research is needed to evaluate the rehabilitation programmes for these patients