A search on Dirac equation

The solutions, in terms of orthogonal polynomials, of Dirac equation with analytically solvable potentials are investigated within a novel formalism by transforming the relativistic equation into a Schrodinger like one. Earlier results are discussed in a unified framework and certain solutions of a large class of potentials are given.Comment: 9 page

Brief communication "Stratospheric winds, transport barriers and the 2011 Arctic ozone hole"

The Arctic stratosphere throughout the late winter and early spring of 2011 was characterized by an unusually severe ozone loss, resulting in what has been described as an ozone hole. The 2011 ozone loss was made possible by unusually cold temperatures throughout the Arctic stratosphere. Here we consider the issue of what constitutes suitable environmental conditions for the formation and maintenance of a polar ozone hole. Our discussion focuses on the importance of the stratospheric wind field and, in particular, the importance of a high latitude zonal jet, which serves as a meridional transport barrier both prior to ozone hole formation and during the ozone hole maintenance phase. It is argued that stratospheric conditions in the boreal winter/spring of 2011 were highly unusual inasmuch as in that year Antarctic-like Lagrangian dynamics led to the formation of a boreal ozone hole

Plasma biomarkers of brain injury in COVID-19 patients with neurological symptoms

Objective: Neurological symptoms (NS) were often reported in COVID-19 infection. We examined the plasma levels of glial fibrillary acidic protein (GFAP) and S100B together, as brain injury biomarkers, in relation to persistent NS in a cohort of patients with COVID-19 during the acute phase of the disease.Methods: A total of 20 healthy controls and 58 patients with confirmed COVID-19 were enrolled in this prospective study. Serum GFAP and S100B levels were measured by using enzymle linked immunoassay method from blood samples.Results: Serum GFAP levels were found to be significantly higher in the severe group than in the controls (p = 0.007). However, serum S100B levels were similar between control and disease groups (p > 0.05). No significant results for GFAP and S100B were obtained between the disease groups depending on whether the sampling time was below or above 5 days (p > 0.05). We did not find a correlation between serum GFAP and S100B levels and the presence of NS (p > 0.05). However, serum S100B levels were slightly higher in patients with multiple NS than in those with a single symptom (p = 0.044).Conclusions: Elevated GFAP was associated with disease severity but not with NS in COVID-19 patients. Whereas, high serum S100B was associated with the multipl NS in these patients. Our data suggest that GFAP and S100B may be of limited value currently in order to represent the neuronal damage, though serving a basis for the future work

Persistent Transport Barrier on the West Florida Shelf

Analysis of drifter trajectories in the Gulf of Mexico has revealed the existence of a region on the southern portion of the West Florida Shelf (WFS) that is not visited by drifters that are released outside of the region. This so-called ``forbidden zone'' (FZ) suggests the existence of a persistent cross-shelf transport barrier on the southern portion of the WFS. In this letter a year-long record of surface currents produced by a Hybrid-Coordinate Ocean Model simulation of the WFS is used to identify Lagrangian coherent structures (LCSs), which reveal the presence of a robust and persistent cross-shelf transport barrier in approximately the same location as the boundary of the FZ. The location of the cross-shelf transport barrier undergoes a seasonal oscillation, being closer to the coast in the summer than in the winter. A month-long record of surface currents inferred from high-frequency (HF) radar measurements in a roughly 60 km $\times$ 80 km region on the WFS off Tampa Bay is also used to identify LCSs, which reveal the presence of robust transient transport barriers. While the HF-radar-derived transport barriers cannot be unambiguously linked to the boundary of the FZ, this analysis does demonstrate the feasibility of monitoring transport barriers on the WFS using a HF-radar-based measurement system. The implications of a persistent cross-shelf transport barrier on the WFS for the development of harmful algal blooms on the shoreward side of the barrier are considered.Comment: Submitted to Geophysical Research Letter

Comparison of chosen physical fitness characteristics of turkish professional basketball players by division and playing position

The purpose of the present study was to compare chosen physical fitness characteristics of Turkish professional basketball players in different divisions (first and second division) and playing positions. Forty-five professional male basketball players (14 guards, 15 forwards, 16 centers) participated in this study voluntarily. For each player, anthropometric measurements were performed, as well as a multi-stage 20 m shuttle run, isokinetic leg strength, squat jump (SJ), countermovement jump (CMJ), 10-30 meter single-sprint and T-drill agility tests. The differences in terms of division were evaluated by independent t-test and the differences by playing position were evaluated by one-way ANOVA with Post Hoc Tukey test. First division players' CMJ measurements were significantly higher than those of second division players' (p≤0.05), whereas second division players' 10 m sprint times were significantly better than those of first division players' (p≤0.05). In addition, forwards and centers were significantly taller than guards. Centers were significantly heavier and their T-drill test performances were inferior to those of forwards and guards (p≤0.05). Moreover, guards had a significantly higher maximal oxygen uptake (VO2 max) than centers. Guards and forwards showed significantly better performance in the 10 and 30 m sprint tests than centers (p≤0.05). Forwards and centers had significantly better left leg flexor strength at 180°.s-1(p≤0.05). In conclusion, the findings of the present study indicated that physical performance of professional basketball players differed among guards, forwards and centers, whereas there were not significant differences between first and second division players. According to the present study, court positions have different demands and physical attributes which are specific to each playing position in professional basketball players. Therefore, these results suggest that coaches should tailor fitness programs according to specific positions on the court. © Editorial Committee of Journal of Human Kinetics

Supersymmetry and the relationship between a class of singular potentials in arbitrary dimensions

The eigenvalues of the potentials $V_{1}(r)=\frac{A_{1}}{r}+\frac{A_{2}}{r^{2}}+\frac{A_{3}}{r^{3}}+\frac{A_{4 }}{r^{4}}$ and $V_{2}(r)=B_{1}r^{2}+\frac{B_{2}}{r^{2}}+\frac{B_{3}}{r^{4}}+\frac{B_{4}}{r^ {6}}$, and of the special cases of these potentials such as the Kratzer and Goldman-Krivchenkov potentials, are obtained in N-dimensional space. The explicit dependence of these potentials in higher-dimensional space is discussed, which have not been previously covered.Comment: 13 pages article in LaTEX (uses standard article.sty). Please check "http://www1.gantep.edu.tr/~ozer" for other studies of Nuclear Physics Group at University of Gaziante