The Critical Temperature of an Anisotropic Superconductor in the Presence of a Homogeneous Magnetic Field and Impurities

The effect of a homogeneous magnetic field and nonmagnetic impurities on the critical temperature of an anisotropic superconductor has been investigated. The role of these pair-breakers in relation to the anisotropy of the order parameter is clarified.Comment: 7 pages, RevTeX, 1 PostScript figur

Metalanguage in L1 English-speaking 12-year-olds: which aspects of writing do they talk about?

Traditional psycholinguistic approaches to metalinguistic awareness in L1 learners elicit responses containing metalanguage that demonstrates metalinguistic awareness of pre-determined aspects of language knowledge. This paper, which takes a more ethnographic approach, demonstrates how pupils are able to engage their own focus of metalanguage when reflecting on their everyday learning activities involving written language. What is equally significant is what their metalanguage choices reveal about their understanding and application of written language concepts

High Energy Gamma--Radiation from the Galactic Center due to Neutralino Annihilation

We study the NGS (Non--dissipative Gravitational Singularity) model, which successfully describes the non--linear stage of evolution of perturbations (see [1], [2] and references therein). This model predicts DM density distribution $\rho(r) \sim r^{-\alpha}$ with $\alpha \simeq 1.8$ which holds from very small distances $r_{\rm min} \simeq 0.01~{\rm pc}$ up to very large distances $r_{\rm max} \simeq 5~{\rm Mpc}$. Assuming the neutralino to be a CDM particle, we calculate the annihilation of neutralinos in the vicinity of the singularity (Galactic Center). If neutralinos are the dominant component of DM in our Galaxy, the produced energy is enough to provide the whole observed activity of the GC. Neutralinos of the most general composition and of mass in the range 20~{\rm GeV} \leq m_\c \leq 1~{\rm TeV} are considered. We find the neutralino compositions which give the relic density needed for the Mixed Dark Matter (MDM) model and we evaluate for these compositions the high--energy ($E_{\gamma} > 100 ~{\rm MeV}$) gamma--ray flux under the constraint that the radio flux is lower than the observational limit. The compositions with the detectable gamma--ray flux which we found are provided by a set of almost pure gaugino states with the neutralino mass between $100$ and $500$ GeV. We demonstrate that a detectable high--energy gamma--ray flux is produced by the neutralino annihilation also in the case when neutralinos provide a small fraction (down to $0.1 \%$) of the DM in our Galaxy. The predicted flux is $F_\gamma \sim 10^{-7}-10^{-8}~{\rm cm}^{-2}~{\rm s}^{-1}$ for E_\gamma \gsim 300~{\rm MeV}Comment: Plain TeX 11 pages 4 figures available on request. Preprint numbers LNGS 94/90 - DFTT 5/9

Neutrino-Lasing in The Early Universe

Recently, Madsen has argued that relativistic decays of massive neutrinos into lighter fermions and bosons may lead, via thermalization, to the formation of a Bose condensate. If correct, this could generate mixed hot and cold dark matter, with important consequences for structure formation. From a detailed study of such decays, we arrive at substantially different conclusions; for a wide range of masses and decay times, we find that stimulated emission of bosons dominates the decay. This phenomenon can best be described as a neutrino laser, pumped by the QCD phase transition. We discuss the implications for structure formation and the dark-matter problem.Comment: 7 pages, 3 figures included as uuencoded file, CITA/93/

Presentation and Outcomes After Medical and Surgical Treatment Versus Medical Treatment Alone of Spontaneous Infectious Spondylodiscitis: A Systematic Literature Review and Meta-Analysis.

Study Design: Systematic literature review. Objectives: The aims of this study were to (1) describe the clinical features, disabilities, and incidence of neurologic deficits of pyogenic spondylodiscitis prior to treatment and (2) compare the functional outcomes between patients who underwent medical treatment alone or in combination with surgery for pyogenic spondylodiscitis. Methods: A systematic literature review was performed using PubMed according to PRISMA guidelines. No year restriction was put in place. Statistical analysis of pooled data, when documented in the original report (ie, number of patients with desired variable and number of patients evaluated), was conducted to determine the most common presenting symptoms, incidence of pre- and postoperative neurologic deficits, associated comorbidities, infectious pathogens, approach for surgery when performed, and duration of hospitalization. Outcomes data, including return to work status, resolution of back pain, and functional recovery were also pooled among all studies and surgery-specific studies alone. Meta-analysis of studies with subgroup analysis of pain-free outcome in surgical and medical patients was performed. Results: Fifty of 1286 studies were included, comprising 4173 patients undergoing either medical treatment alone or in combination with surgery. Back pain was the most common presenting symptom, reported in 91% of patients. Neurologic deficit was noted in 31% of patients. Conclusion: Medical management remains first-line treatment of infectious pyogenic spondylodiscitis. Surgery may be indicated for progressive pain, persistent infection on imaging, deformity or neurologic deficits. If surgery is required, reported literature shows potential for significant pain reduction, improved neurologic function and a high number of patients returning to a normal functional/work status

The Environmental Context and Function of Burnt-Mounds : New Studies of Irish Fulachtaí Fiadh

The authors acknowledge funding from The Leverhulme Trust (F/00144/AI) and assistance from a large number of individuals including; Margaret Gowen (access to sites and assistance throughout),A. Ames, H, Essex (pollen processing), S. Rouillard & R. Smith (illustrations), C. McDermott, S. Bergerbrandt, all the staff of Margaret Gowen & Co. Ltd, TVAS Ireland and CRDS. Excavation works and some post-excavation analysis was paid for my Bord Gáis and the National Roads Authority (now Transport Infrastructure Ireland). Thanks also to David Smith for access to the Maureen Girling collection and assistance with identifications.Peer reviewedPostprintPostprin

Exact Superpotentials in Four Dimensions

Supersymmetric gauge theories in four dimensions can display interesting non-perturbative phenomena. Although the superpotential dynamically generated by these phenomena can be highly nontrivial, it can often be exactly determined. We discuss some general techniques for analyzing the Wilsonian superpotential and demonstrate them with simple but non-trivial examples.Comment: 32 pages, RU-94-2

Exact Results on the Space of Vacua of Four Dimensional SUSY Gauge Theories

We consider four dimensional quantum field theories which have a continuous manifold of inequivalent exact ground states -- a moduli space of vacua. Classically, the singular points on the moduli space are associated with extra massless particles. Quantum mechanically these singularities can be smoothed out. Alternatively, new massless states appear there. These may be the elementary massless particles or new massless bound states.Comment: 19 pages, RU-94-1

The symbiotic star CH Cygni – II. The ejecta from the 1998-2000 active phase

We present Hubble Space Telescope (HST) imaging, a Very Large Array (VLA) radio map (4.74 GHz), optical high-resolution (echelle) spectroscopy and UBV photoelectric photometry of the symbiotic star CH Cyg obtained during its 1998–2000 active phase. The HST imaging, taken during eclipse, shows the central stars are embedded in a nebula extending to 620 ± 150 au for a distance of 270 ± 66 pc. The inner nebula is strongly influenced by the onset of activity and associated outflow in 1998. The surface brightness contours of the contemporaneous radio VLA observation agree well with HST images. Photometric observations of the broad 1999 U-minimum suggest that it is due to the eclipse of the active hot component by the giant on the long-period (14.5 yr) outer orbit. We also find that the onset of the 1998 and the 1992 active periods occur at the same orbital phase of the inner binary. Spectroscopic observations reveal two types of outflow from the active star: a high-velocity (>1200 km s−1) hot star wind sporadically alternating with a more massive outflow indicated by P-Cygni-like profiles. We present evidence connecting the extended nebulosity with the high-velocity shocked outflow, and hence the activity in the central binary

A thorough study of the intriguing X-ray emission from the Cartwheel ring

We present the results from the high resolution Chandra observation of the Cartwheel galaxy. Many individual sources are resolved in the image, mostly associated with the outer ring. All detected sources have a very high X-ray luminosity ($\geq 10^{39}$ erg s$^{-1}$)that classifies them as Ultra Luminous X-ray sources (ULX). The brightest of them is possibly the most luminous individual non-nuclear source observed so far, with L$_X \sim 10^{41}$ erg s$^{-1}$ (at D=122 Mpc). The spatial extent of this source is consistent with a point source at the Chandra resolution. The luminosity function of individual X-ray sources extends about an order of magnitude higher than previously reported in other galaxies. We discuss this in the context of the "universal" luminosity function for High Mass X-ray Binaries and we derive a Star Formation Rate higher than in other starburst galaxies studied so far. A diffuse component, associated with hot gas, is present. However, deeper observations that we will obtain with XMM-Newton are needed to constrain its properties.Comment: 14 pages; accepted for publication in A&