Drum vortons in high density QCD

Recently it was shown that high density QCD supports of number of topological defects. In particular, there are U(1)_Y strings that arise due to K^0 condensation that occurs when the strange quark mass is relatively large. The unique feature of these strings is that they possess a nonzero K^+ condensate that is trapped on the core. In the following we will show that these strings (with nontrivial core structure) can form closed loops with conserved charge and currents trapped on the string worldsheet. The presence of conserved charges allows these topological defects, called vortons, to carry angular momentum, which makes them classically stable objects. We also give arguments demonstrating that vortons carry angular momentum very efficiently (in terms of energy per unit angular momentum) such that they might be the important degrees of freedom in the cores of neutron stars.Comment: 11 pages, accepted for publication in Physical Review

Molecular Cloud Structure in the Magellanic Clouds: Effect of Metallicity

The chemical structure of neutral clouds in low metallicity environments is examined with particular emphasis on the H to H_2 and C+ to CO transitions. We observed near-IR H_2 lines and the CO J=1-0 line from 30 Doradus and N159/N160 in the Large Magellanic Cloud and from DEM S 16, DEM S 37, and LI-SMC 36 in the Small Magellanic Cloud. We find that the H_2 emission is UV-excited and that (weak) CO emission always exists (in our surveyed regions) toward positions where H_2 and [CII] emission have been detected. Using a PDR code and a radiative transfer code, we simulate the emission of line radiation from spherical clouds and from large planar clouds. Because the [CII] emission and H_2 emission arise on the surface of the cloud and the lines are optically thin, these lines are not affected by changes in the relative sizes of the neutral cloud and the CO bearing core, while the optically thick CO emission can be strongly affected. The sizes of clouds are estimated by measuring the deviation of CO emission strength from that predicted by a planar cloud model of a given size. The average cloud column density and therefore size increases as the metallicity decreases. Our result agrees with the photoionization regulated star formation theory by Mc Kee (1989).Comment: 45 Pages including 15 figures. To be published in the ApJ May 10, 1998 issue, Vol. 49

Can we predict the clinical outcome of arthroscopic partial meniscectomy? A systematic review

NHS-Prospero registration number 42016048592 Objective In order to make a more evidence-based selection of patients who would benefit the most from arthroscopic partial meniscectomy (APM), knowledge of prognostic factors is essential. We conducted a systematic review of predictors for the clinical outcome following APM. Design Systematic review Data sources Medline, Embase, Cochrane Central Register, Web of Science, SPORTDiscus, PubMed Publisher, Google Scholar Inclusion criteria Report an association between factor(s) and clinical outcome; validated questionnaire; follow-up >1 year. Exclusion criteria 1 year) are associated with worse clinical outcome following APM. In addition, resecting >50% of meniscal tissue and leaving a non-intact meniscal rim after meniscectomy are intra-articular predictive factors for worse clinical outcome. Moderate evidence was found that sex, onset of symptoms (acute or chronic), tear type or preoperative sport level are not predictors for clinical outcome. Conflicting evidence was found for the prognostic value of age, perioperative chondral damage, body mass index and leg alignment. Summary/conclusion Long duration of symptoms (>1 year), radiological knee osteoarthritis and resecting >50% of meniscus are associated with a worse clinical outcome following APM. These prognostic factors should be considered in clinical decision making for patients with meniscal tears

Vortex Rings in two Component Bose-Einstein Condensates

We study the structure of the vortex core in two-component Bose-Einstein condensates. We demonstrate that the order parameter may not vanish and the symmetry may not be restored in the core of the vortex. In this case such vortices can form vortex rings known as vortons in particle physics literature. In contrast with well-studied superfluid $^4He$, where similar vortex rings can be stable due to Magnus force only if they move, the vortex rings in two-component BECs can be stable even if they are at rest. This beautiful effect was first discussed by Witten in the cosmic string context, where it was shown that the stabilization occurs due to condensation of the second component of the field in the vortex core. This second condensate trapped in the core may carry a current along the vortex ring counteracting the effect of string tension that causes the loop to shrink. We speculate that such vortons may have been already observed in the laboratory. We also speculate that the experimental study of topological structures in BECs can provide a unique opportunity to study cosmology and astrophysics by doing laboratory experiments.Comment: 21 pages, 2 figure

Twenty-Year Follow-up Study Comparing Operative Versus Nonoperative Treatment of Anterior Cruciate Ligament Ruptures in High-Level Athletes

Background: An anterior cruciate ligament (ACL) rupture has major consequences at midterm follow-up, with an increasing chance of developing an old knee in a young patient. The long-term (≥20 years) effects of the operative and nonoperative treatment of ACL ruptures are still unclear. Purpose: To compare the long-term treatment outcomes of operative versus nonoperative treatment of ACL ruptures in high-level athletes. Study Design: Cohort study; Level of evidence, 2. Methods: Fifty patients with an ACL rupture were eligible for participation, and they were treated either nonoperatively (n = 25) in 1992, consisting of structured rehabilitation and lifestyle adjustments, or operatively (n = 25) between 1994 and 1996 with an arthroscopic transtibial bone–patellar tendon–bone technique. The patients in the nonoperative group were drawn from those who responded well to 3 months of nonoperative treatment, whereas the patients in the operative group were drawn from those who had persistent instability after 3 months of nonoperative treatment. Both groups were pair-matched and assessed at 10- and 20-year follow-up regarding radiological knee osteoarthritis, functional outcomes (Lysholm, International Knee Documentation Committee [IKDC], Tegner, Knee injury and Osteoarthritis Outcome Score), meniscal status, and knee stability (KT-1000 arthrometer, pivot-shift test, Lachman test, 1-legged hop test). Results: All 50 patients (100%) were included in the current study for follow-up. After 20 years, we found knee osteoarthritis in 80% of the operative group compared with 68% of the nonoperative group (P =.508). There was no difference between groups regarding functional outcomes and meniscectomy performed. The median IKDC subjective score was 81.6 (interquartile range [IQR], 59.8-89.1) for the operative group and 78.2 (IQR, 61.5-92.0) for the nonoperative group (P =.679). Regarding the IKDC objective score, 21 patients (84%) in the operative group had a normal or near normal score (A and B) compared with 5 patients (20%) in the nonoperative group (P <.001). The pivot-shift test finding was negative in 17 patients (68%) versus 3 patients (13%) for the operative and nonoperative groups, respectively (P <.001), and the Lachman test finding was negative in 12 patients (48%) versus 1 patient (4%), respectively (P =.002). Conclusion: In this retrospective pair-matched follow-up study, we found that after 20-year follow-up, there was no difference in knee osteoarthritis between operative versus nonoperative treatment when treatment was allocated on the basis of a patient’s response to 3 months of nonoperative treatment. Although knee stability was better in the operative group, it did not result in better subjective and objective functional outcomes

RANTES/CCL5 and risk for coronary events: Results from the MONICA/KORA Augsburg case-cohort, Athero-express and CARDIoGRAM studies

Background: The chemokine RANTES (regulated on activation, normal T-cell expressed and secreted)/CCL5 is involved in the pathogenesis of cardiovascular disease in mice, whereas less is known in humans. We hypothesised that its relevance for atherosclerosis should be reflected by associations between CCL5 gene variants, RANTES serum concentrations and protein levels in atherosclerotic plaques and risk for coronary events. Methods and Findings: We conducted a case-cohort study within the population-based MONICA/KORA Augsburg studies. Baseline RANTES serum levels were measured in 363 individuals with incident coronary events and 1,908 non-cases (mean follow-up: 10.2±

Self-generated magnetic fields in laser plasmas

Megagauss-level magnetic fields were predicted theoretically and observed experimentally. The field generation due to resonance absorption of laser light and thermoelectric currents is discussed. An experiment to measure these fields by Faraday rotation of light (2660A) is described. (auth