A self-sustaining nonlinear dynamo process in Keplerian shear flows

A three-dimensional nonlinear dynamo process is identified in rotating plane Couette flow in the Keplerian regime. It is analogous to the hydrodynamic self-sustaining process in non-rotating shear flows and relies on the magneto-rotational instability of a toroidal magnetic field. Steady nonlinear solutions are computed numerically for a wide range of magnetic Reynolds numbers but are restricted to low Reynolds numbers. This process may be important to explain the sustenance of coherent fields and turbulent motions in Keplerian accretion disks, where all its basic ingredients are present.Comment: 4 pages, 7 figures, accepted for publication in Physical Review Letter

Transport coefficients of heavy quarks around TcT_c at finite quark chemical potential

The interactions of heavy quarks with the partonic environment at finite temperature $T$ and finite quark chemical potential $\mu_q$ are investigated in terms of transport coefficients within the Dynamical Quasi-Particle model (DQPM) designed to reproduce the lattice-QCD results (including the partonic equation of state) in thermodynamic equilibrium. These results are confronted with those of nuclear many-body calculations close to the critical temperature $T_c$. The hadronic and partonic spatial diffusion coefficients join smoothly and show a pronounced minimum around $T_c$, at $\mu_q=0$ as well as at finite $\mu_q$. Close and above $T_c$ its absolute value matches the lQCD calculations for $\mu_q=0$. The smooth transition of the heavy quark transport coefficients from the hadronic to the partonic medium corresponds to a cross over in line with lattice calculations, and differs substantially from perturbative QCD (pQCD) calculations which show a large discontinuity at $T_c$. This indicates that in the vicinity of $T_c$ dynamically dressed massive partons and not massless pQCD partons are the effective degrees-of-freedom in the quark-gluon plasma.Comment: 4 pages, 4 figure

Heavy flavor in relativistic heavy-ion collisions

We study charm production in ultra-relativistic heavy-ion collisions by using the Parton-Hadron-String Dynamics (PHSD) transport approach. The initial charm quarks are produced by the PYTHIA event generator tuned to fit the transverse momentum spectrum and rapidity distribution of charm quarks from Fixed-Order Next-to-Leading Logarithm (FONLL) calculations. The produced charm quarks scatter in the quark-gluon plasma (QGP) with the off-shell partons whose masses and widths are given by the Dynamical Quasi-Particle Model (DQPM), which reproduces the lattice QCD equation-of-state in thermal equilibrium. The relevant cross sections are calculated in a consistent way by employing the effective propagators and couplings from the DQPM. Close to the critical energy density of the phase transition, the charm quarks are hadronized into $D$ mesons through coalescence and/or fragmentation. The hadronized $D$ mesons then interact with the various hadrons in the hadronic phase with cross sections calculated in an effective lagrangian approach with heavy-quark spin symmetry. The nuclear modification factor $R_{AA}$ and the elliptic flow $v_2$ of $D^0$ mesons from PHSD are compared with the experimental data from the STAR Collaboration for Au+Au collisions at $\sqrt{s_{NN}}$ =200 GeV and to the ALICE data for Pb+Pb collisions at $\sqrt{s_{NN}}$ =2.76 TeV. We find that in the PHSD the energy loss of $D$ mesons at high $p_T$ can be dominantly attributed to partonic scattering while the actual shape of $R_{AA}$ versus $p_T$ reflects the heavy-quark hadronization scenario, i.e. coalescence versus fragmentation. Also the hadronic rescattering is important for the $R_{AA}$ at low $p_T$ and enhances the $D$-meson elliptic flow $v_2$.Comment: 8 pages, 3 figures, to be published in the Proceedings of the 15th International Conference on Strangeness in Quark Matter (SQM2015), 6-11 July 2015, JINR, Dubna, Russi

Predictors of unfavourable tuberculosis treatment outcome in Bilene District, Gaza Province, Mozambique: A retrospective analysis, 2016 - 2019

Background. Tuberculosis (TB) is a serious public health problem and remains one of the leading causes of death from an infectious agent globally. Mozambique is one of 30 countries considered to have a high TB burden.Objectives. To describe the clinical characteristics of TB in children and adults in Bilene District in Gaza Province, Mozambique, over 43 months and to assess determinants of unfavourable treatment outcomes.Methods. This retrospective cohort study took place from 1 January 2016 to 31 July 2019 in Bilene District, Gaza. We included patients in the TB register at the Centro de Saúde de Macia TB unit with available data on final treatment outcome. Predictors of unfavourable outcomes were determined using multivariable logistic regression models.Results. A total of 3 012 TB-infected patients were registered in the TB unit of the Macia health facility during the study period: 358 (11.9%) were children (<14 years), 1 522 (50.5%) were male, and 2 581 (85.7%) were new TB cases. No bacteriological test was performed at diagnosis in 1 250 patients (41.5%). Treatment was successful in 2 863 patients (95.1%), with better outcomes in children than in adults (98.0% v. 94.6%; p=0.005). Although mortality (n=97; 3.2%) was low in both groups, the proportion who died was lower in children compared with adults (1.4% v. 3.5%; p=0.035). Multivariable logistic regression analysis showed that unfavourable outcomes were more likely in men compared with women (adjusted odds ratio (aOR) 1.48; 95% confidence interval (CI) 1.04 - 2.12; p=0.029), in patients with recurrent TB infection compared with newly infected patients (aOR 1.63; 95% CI 1.05 - 2.50; p=0.027), and in patients co-infected with TB and HIV compared with HIV-negative TB-infected patients (aOR 2.17; 95% CI 1.43 - 3.29; p<0.001). The factor conferring the most risk for an unfavourable outcome was positive microbiological sputum results (aOR 5.27; 95% CI 3.25 - 8.54; p<0.001).Conclusions. Factors independently associated with an unfavourable TB treatment outcome were male sex, recurrent TB infection, having positive microbiology, and co-infection with HIV. It remains crucial to improve data quality and adherence to TB screening and diagnostic algorithms

Dynamics of Executive Functions, Basic Psychological Needs, Impulsivity, and Depressive Symptoms in American Football Players

Executive functions play an important role in sports since the ability to plan, organize,and regulate behavior to reach an objective or goal depends on these functions. Someof the components of executive functions, such as inhibition of impulsive behavior andcognitive flexibility, are necessary for contact sports (e.g., American football) to carryout successful plays on the sports field. Executive functions have been studied in thesporting environment, but their relationship with the athletes’ basic psychological needs(BPN), such as autonomy, competence, and relatedness, remains unexplored. Due tothe importance of motivational processes over cognitive functions and in the generatedadaptive results in athletes, this relationship should be taken into account. Therefore, theaim of this study was to analyze and compare executive functioning and psychologicalneed thwarting overimpulsivity and psychological distress, before and after the season(4 months) in 28 undergraduate football players. Neuropsychological and psychologicaltests were applied. The results showed that there was an improvement in inhibitionand planning at the end of the season. There was also an increase in attention andmotor impulsiveness, and a decrease in need thwarting at the end of the season.A positive association between executive function, impulsiveness, psychological needs,and affective symptoms were also found. Our findings reveal the dynamics of sport-related psychological variables throughout the sport season in American football players,the association of these for the achievement of sport success, and the importance ofencouraging proper management of emotions

In vitro Validation of Quantitative Light-Induced Fluorescence for the Diagnosis of Enamel Fluorosis in Permanent Teeth

This study aimed to validate quantitative light-induced fluorescence (QLF) as a diagnostic tool for mild and moderate enamel fluorosis in permanent teeth, comparing it to visual diagnosis and histological assessment completed using polarized light microscopy (PLM). The buccal surfaces of 139 teeth were visually classified using the Thylstrup and Fejerskov Index (TFI) into sound (TFI 0; n = 17), mild (TFI 1-2; n = 69), and moderate (TFI 3-4; n = 43) fluorosis. Fluorosis was then assessed with QLF (variables ΔF, A, and ΔQ at 5-, 15-, and 30-radiance thresholds) using as reference areas the entire surface and a region of interest (ROI), identified as the most representative region of a fluorosis lesion. PLM images of longitudinal thin sections including the ROI were assessed for histological changes. Correlations among TFI, PLM, and QLF were determined. A receiver-operating characteristic curve was conducted to determine QLF's diagnostic accuracy when compared to the TFI and PLM assessments. This was used to assess the probability that the images were correctly ranked according to severity as determined by PLM and TFI. A positive correlation was found between QLF and PLM, and between QLF and TFI. QLF showed the highest sensitivity and specificity for the diagnosis of mild fluorosis. There was also a strong agreement between TFI and PLM. The selection of a ROI resulted in a stronger correlation with TFI and PLM than when the entire surface was used. The study results indicate that defining an ROI for QLF assessments is a valid method for the diagnosis of mild and moderate enamel fluorosis