Semiclassical theory of quasiparticles in the superconducting state

We have developed a semiclassical approach to solving the Bogoliubov - de Gennes equations for superconductors. It is based on the study of classical orbits governed by an effective Hamiltonian corresponding to the quasiparticles in the superconducting state and includes an account of the Bohr-Sommerfeld quantisation rule, the Maslov index, torus quantisation, topological phases arising from lines of phase singularities (vortices), and semiclassical wave functions for multi-dimensional systems. The method is illustrated by studying the problem of an SNS junction and a single vortex.Comment: 74 pages, 19 figures, 3 tables. Submitted to Academic Press for possible publicatio

Factorizing the hard and soft spectator scattering contributions for the nucleon form factor F_1 at large Q^2

We investigate the soft spectator scattering contribution for the FF $F_{1}$. We focus our attention on factorization of the hard-collinear scale $\sim Q\Lambda$ corresponding to transition from SCET-I to SCET-II. We compute the leading order jet functions and find that the convolution integrals over the soft fractions are logarithmically divergent. This divergency is the consequence of the boost invariance and does not depend on the model of the soft correlation function describing the soft spectator quarks. Using as example a two-loop diagram we demonstrated that such a divergency corresponds to the overlap of the soft and collinear regions. As a result one obtains large rapidity logarithm which must be included in the correct factorization formalism. We conclude that a consistent description of the factorization for $F_{1}$ implies the end-point collinear divergencies in the hard and soft spectator contributions, i.e. convolution integrals with respect to collinear fractions are not well-defined. Such scenario can only be realized when the twist-3 nucleon distribution amplitude has specific end-point behavior which differs from one expected from the evolution of the nucleon distribution amplitude. Such behavior leads to the violation of the collinear factorization for the hard spectator scattering contribution. We suggest that the soft spectator scattering and chiral symmetry breaking provide the mechanism responsible for the violation of collinear factorization in case of form factor $F_{1}$.Comment: 25 pages, 6 figures, text is improved, few typos corrected, one figure added, statement about end-point behavior of the nucleon DA is formulated more accuratel

Predictive Factors of Hamstring Tendon Regeneration and Functional Recovery After Harvesting: A Prospective Follow-up Study

Background: Semitendinosus and gracilis tendons may regenerate after harvesting for ligament reconstruction procedures. However, predictive factors of tendon regeneration and the extent of functional recovery remain unclear. Purpose: To identify predictive factors for hamstring tendon regeneration and to examine the morbidity of nonregenerated hamstring tendons. Study Design: Cohort study; Level of evidence, 3. Methods: Of the 154 patients who were included in a prospective follow-up study, 79 underwent reconstruction of the anterior cruciate ligament entailing the hamstring tendons and met the following inclusion criteria: (1) anterior cruciate ligament rupture diagnosed by physical examination and magnetic resonance imaging (MRI), (2) MRI within 6 months after trauma, (3) age between 18 and 45 years, and (4) 2-year follow-up MRI data available. Hamstring tendon regeneration was assessed as complete if a tendon-like structure could be visualized at the level of the joint line or more cranially. Patient characteristics—such as age, sex, body mass index, alcohol/nicotine use, activity level (Tegner scores), and functional instability (1-legged hop test)—were evaluated preoperatively and at 2 years to determine predictive factors for tendon regeneration or examine functional recovery of hamstring tendon regeneration. Results: At 2 years’ follow-up, 67.1% of the patients showed regeneration of semitendinosus tendons, 81.0% of gracilis tendons, and 59.5% of both tendons. The likelihood of semitendinosus tendon regeneration significantly decreased with aging (odds ratio [OR], 0.92 change per year of age; 95% CI, 0.84-0.99; P =.03) and smoking (OR, 0.20; 95% CI, 0.05-0.77; P =.02). No predictive factor was found for gracilis tendon regeneration. Regeneration of the semitendinosus and gracilis tendons was negatively related with smoking (OR, 0.22; 95% CI, 0.06-0.79; P =.02). Patients without regeneration showed similar postoperative visual analog scale scores during physical activity, similar Tegner scores, and a significant decrease of the upper leg circumference, as compared with their preoperative results. Regardless of the regeneration status, 1-legged hop test results significantly increased at 2-year follow-up. Conclusion: Hamstring tendon regeneration occurs less frequently in older patients and in smokers. However, absence of regenerated tendons does not seem to cause a loss of function

Higher Resonance Contamination of pi NN Couplings Obtained Via the Three-Point Function Method in QCD Sum Rules

We investigate the size of potential higher pseudoscalar resonance contaminations of the estimates of isospin-conserving and isospin-violating $\pi NN$ couplings obtained using the 3-point function method in QCD sum rules. For the isospin-conserving case it is shown that conventional models of the isovector pseudoscalar spectral function imply resonance decay constants large enough to create significant contaminations, and that assuming these models are incorrect, and that the decay constants are actually much smaller, implies physically implausible values for the flavor-breaking quark condensate ratios. For the isospin-violating case it is shown explicitly that such resonance contamination is unavoidably present and precludes using the 3-point function method as a means of estimating the at present unmeasured isospin-violating $\pi NN$ couplings.Comment: 8 page

Homogenized dynamics of stochastic partial differential equations with dynamical boundary conditions

A microscopic heterogeneous system under random influence is considered. The randomness enters the system at physical boundary of small scale obstacles as well as at the interior of the physical medium. This system is modeled by a stochastic partial differential equation defined on a domain perforated with small holes (obstacles or heterogeneities), together with random dynamical boundary conditions on the boundaries of these small holes. A homogenized macroscopic model for this microscopic heterogeneous stochastic system is derived. This homogenized effective model is a new stochastic partial differential equation defined on a unified domain without small holes, with static boundary condition only. In fact, the random dynamical boundary conditions are homogenized out, but the impact of random forces on the small holes' boundaries is quantified as an extra stochastic term in the homogenized stochastic partial differential equation. Moreover, the validity of the homogenized model is justified by showing that the solutions of the microscopic model converge to those of the effective macroscopic model in probability distribution, as the size of small holes diminishes to zero.Comment: Communications in Mathematical Physics, to appear, 200

The nature of faint radio galaxies at high redshifts

Large scale structure and cosmolog

17-OHPC to Prevent Recurrent Preterm Birth in Singleton Gestations (PROLONG Study): A Multicenter, International, Randomized Double-Blind Trial

Background âwomen with a history of spontaneous preterm birth (SPTB) are at a significantly increased risk for recurrent preterm birth (PTB). To date, only one large U.S. clinical trial comparing 17-OHPC (17-α-hydroxyprogesterone caproate or 17P) to placebo has been published, and this trial was stopped early due to a large treatment benefit. Objective âThis study aimed to assess whether 17-OHPC decreases recurrent PTB and neonatal morbidity in women with a prior SPTB in a singleton gestation. Study Design âThis was a double-blind, placebo-controlled international trial involving women with a previous singleton SPTB (clinicaltrials.gov: NCT 01004029). Women were enrolled at 93 clinical centers (41 in the United States and 52 outside the United States) between 16 0/7 to 20 6/7 weeks in a 2:1 ratio, to receive either weekly intramuscular (IM) injections of 250 mg of 17-OHPC or an inert oil placebo; treatment was continued until delivery or 36 weeks. Co-primary outcomes were PTB < 35 weeks and a neonatal morbidity composite index. The composite included any of the following: Neonatal death, grade 3 or 4 intraventricular hemorrhage, respiratory distress syndrome, bronchopulmonary dysplasia, necrotizing enterocolitis, or proven sepsis. A planned sample size of 1,707 patients was estimated to provide 98% power to detect a 30% reduction in PTB < 35 weeks (30% to 21%) and 90% power to detect a 35% reduction in neonatal composite index (17%-11%) using a two-sided type-I error of 5%. Finally, this sample size would also provide 82.8% power to rule out a doubling in the risk of fetal/early infant death assuming a 4% fetal/early infant death rate. Analysis was performed according to the intention-to-treat principle. Results âaseline characteristics between the 1,130 women who received 17-OHPC and 578 women who received placebo were similar. Overall, 87% of enrolled women were Caucasian, 12% had >1 prior SPTB, 7% smoked cigarettes, and 89% were married/lived with partner. Prior to receiving study drug, 73% women had a transvaginal cervical length measurement performed and <2% had cervical shortening <25 mm. There were no significant differences in the frequency of PTB < 35 weeks (17-OHPC 11.0% vs. placebo 11.5%; relative risk = 0.95 [95% confidence interval (CI): 0.71-1.26]) or neonatal morbidity index (17-OHPC 5.6% vs. placebo 5.0%; relative risk = 1.12 [95% CI: 0.68-1.61]). There were also no differences in frequency of fetal/early infant death (17-OHPC 1.7% vs. placebo 1.9%; relative risk = 0.87 [95% CI: 0.4-1.81]. Maternal outcomes were also similar. In the subgroup of women enrolled in the United States (n = 391; 23% of all patients), although the rate of PTB < 35 weeks was higher than the overall study population, there were no statistically significant differences between groups (15.6% vs. 17.6%; relative risk = 0.88 [95% CI: 0.55, 1.40]. Conclusion âin this study population, 17-OHPC did not decrease recurrent PTB and was not associated with increased fetal/early infant death

Genetic Sharing with Cardiovascular Disease Risk Factors and Diabetes Reveals Novel Bone Mineral Density Loci.

Bone Mineral Density (BMD) is a highly heritable trait, but genome-wide association studies have identified few genetic risk factors. Epidemiological studies suggest associations between BMD and several traits and diseases, but the nature of the suggestive comorbidity is still unknown. We used a novel genetic pleiotropy-informed conditional False Discovery Rate (FDR) method to identify single nucleotide polymorphisms (SNPs) associated with BMD by leveraging cardiovascular disease (CVD) associated disorders and metabolic traits. By conditioning on SNPs associated with the CVD-related phenotypes, type 1 diabetes, type 2 diabetes, systolic blood pressure, diastolic blood pressure, high density lipoprotein, low density lipoprotein, triglycerides and waist hip ratio, we identified 65 novel independent BMD loci (26 with femoral neck BMD and 47 with lumbar spine BMD) at conditional FDR < 0.01. Many of the loci were confirmed in genetic expression studies. Genes validated at the mRNA levels were characteristic for the osteoblast/osteocyte lineage, Wnt signaling pathway and bone metabolism. The results provide new insight into genetic mechanisms of variability in BMD, and a better understanding of the genetic underpinnings of clinical comorbidity