Confining properties of QCD at finite temperature and density

A disorder parameter detecting dual superconductivty of the vacuum is used as a probe to characterize the confining properties of the phase diagram of two color QCD at finite temperature and density. We obtain evidence for the disappearing of dual superconductivity (deconfinement) induced by a finite density of baryonic matter, as well as for a coincidence of this phenomenon with the restoration of chiral symmetry both at zero and finite density. The saturation transition induced by Pauli blocking is studied as well, and a general warning is given about the possible effects that this unphysical transition could have on the study of the QCD phase diagram at strong values of the gauge coupling.Comment: 13 pages, 23 figure

SXP 7.92: A Recently Rediscovered Be/X-ray Binary in the Small Magellanic Cloud, Viewed Edge On

We present a detailed optical and X-ray study of the 2013 outburst of the Small Magellanic Cloud Be/X-ray binary SXP 7.92, as well as an overview of the last 18 years of observations from OGLE (Optical Gravitational Lensing Experiment), RXTE, Chandra and XMM-Newton. We revise the position of this source to RA(J2000) = 00:57:58.4, Dec(J2000) = −72:22:29.5 with a 1σ uncertainty of 1.5 arcsec, correcting the previously reported position by Coe et al. by more than 20 arcmin. We identify and spectrally classify the correct counterpart as a B1Ve star. The optical spectrum is distinguished by an uncharacteristically deep narrow Balmer series, with the Hα line in particular having a distinctive shell profile, i.e. a deep absorption core embedded in an emission line. We interpret this as evidence that we are viewing the system edge on and are seeing self-obscuration of the circumstellar disc. We derive an optical period for the system of 40.0 ± 0.3 d, which we interpret as the orbital period, and present several mechanisms to describe the X-ray/optical behaviour in the recent outburst, in particular the ‘flares'and ‘dips’ seen in the optical light curve, including a transient accretion disc and an elongated precessing disc

Heuristic Learning as a Method for Improving Students’ Teamwork Skills in Physical Education

Transversal skills are the knowledge, skills, and personal qualities that are currently needed to meet the demands of the working world and everyday life. Schools have the task of equipping students with these skills, working not only on disciplinary goals but also on operational–behavioral goals. In 2018, the European Union adopted new recommendations on eight key competencies for lifelong learning and asked schools to implement new methods to develop these recommendations. To be successful, it is necessary to stimulate students’ development of these competences, which are also called soft skills, from the earliest years of the school experience. Physical education (PE) is called upon to make its contribution. In Italy, the two teaching methods used during PE classes are prescriptive teaching and heuristic learning. It is not clear which of the two methods is the most effective in improving soft skills, especially the skills involved in teamwork. The objective of this article was to compare the effects of these two teaching methods on students’ teamwork skills during PE classes in primary schools. After verifying the normality of the data, a Student’s t-test for dependent samples was performed to assess pre-test and post-test differences in each of two groups, while a Student’s t-test for independent samples was performed to compare the two groups after 3 months. Heuristic learning proved to be the most effective method for improving teamwork skills. The results may make an important contribution to future teacher training on the most effective teaching methods for developing students’ soft skill

Theta dependence of the vacuum energy in the SU(3) gauge theory from the lattice

We report on a precise computation of the topological charge distribution in the SU(3) Yang--Mills theory. It is carried out on the lattice with high statistics Monte Carlo simulations by employing the definition of the topological charge suggested by Neuberger's fermions. We observe significant deviations from a Gaussian distribution. Our results disfavour the theta behaviour of the vacuum energy predicted by instanton models, while they are compatible with the expectation from the large Nc expansion.Comment: Plain latex, 4 pages, 2 figure

Motor Current Cyclic-Non-Stationary Analysis for Bearing Diagnostic

The Motor Current Signature Analysis (MCSA) is a research area focused on the diagnosis of components of electric motors based on post-processing of the current signal mainly. In particular, the bearing diagnostics is based on two different assumptions: the fault on the bearing causes a vibration of the shaft it supports, so there is an air gap variation between stator and rotor causing a modulation in the current signal; the fault on the bearing hinders the rotation of the shaft, so it can be modeled as an additional loading torque that the motor satisfies increasing the current signal. In this paper, a cyclic-non-stationarity analysis of the motor current is used to assess the status of ball-bearings in servomotors, running at variable speed. Both speed of the motor and motor current are provided by the control loop of the servomotor, that is no external sensors are used. The cyclic nature of the application allows an average of the cyclic-cyclic order maps to increase the signal-to-noise ratio. The proposed technique is successfully applied to both healthy and faulty bearings

Gauge-invariant quark-antiquark nonlocal condensates in lattice QCD

We study, by numerical simulations on a lattice, the behaviour of the gauge-invariant quark-antiquark nonlocal condensates in the QCD vacuum with dynamical fermions. A determination is also done in the quenched approximation and the results are compared with the full-QCD case. The fermionic correlation length is extracted and compared with the analogous gluonic quantity.Comment: 14 pages, LaTeX file, + 6 PS figure

Simultaneous sinus lift and implant placement using lateral approach in atrophic posterior maxilla with residual bone height of 5 mm or less. A systematic review

Aim To test both success and survival rate of implant placed simultaneously with sinus lift in atro-phic posterior maxilla with a residual bone height of less than 5 mm. Materials and methods A computer search strategy was developed for the following electronic databases: MEDLINE/ PubMed and EMBASE. All the relevant articles were screened involving controlled clinical trials, randomized clinical trials, prospective cohort studies. Results The selection process yielded 12 studies, published between 1999 and 2016, 6 of which were prospective, 1 was a randomized controlled trial, 5 were controlled studies. Conclusions Within the limitation of this systematic review, the qualitative data analysis revealed that the survival rate of implants placed in grafted sinus ranged from 61% to 100%; on the other hand, the success rate ranged between 75.3% to 94.8%. No significant differences were detected regarding different grafting materials used. In order to understand if the one-stage pro-cedure is an effective and predictable surgical alternative in critically resorbed maxillae, larger and well designed clinical trials are needed

Dynamical Symmetry Breaking in Models with the Yukawa Interaction

We discuss models with a massless fermion and a self-interacting massive scalar field with the Yukawa interaction. The chiral condensate and the fermion mass are calculated analytically. It is shown that the models have a phase transition as a function of the squared mass of the scalar field.Comment: 7 pages, no figures, in Eqs. (7) and (11) one coefficient was change

The distribution of equivalent widths in long GRB afterglow spectra

The extreme brightness of gamma-ray burst (GRB) afterglows and their simple spectral shape make them ideal beacons to study the interstellar medium of their host galaxies through absorption line spectroscopy. Using 69 low-resolution GRB afterglow spectra, we conduct a study of the rest-frame equivalent width (EW) distribution of features with an average rest-frame EW larger than 0.5 A. To compare an individual GRB with the sample, we develop EW diagrams as a graphical tool, and we give a catalogue with diagrams for the 69 spectra. We introduce a line strength parameter (LSP) that allows us to quantify the strength of the absorption features as compared to the sample by a single number. Using the distributions of EWs of single-species features, we derive the distribution of column densities by a curve of growth (CoG) fit. We find correlations between the LSP and the extinction of the GRB, the UV brightness of the host galaxies and the neutral hydrogen column density. However, we see no significant evolution of the LSP with the redshift. There is a weak correlation between the ionisation of the absorbers and the energy of the GRB, indicating that, either the GRB event is responsible for part of the ionisation, or that galaxies with high-ionisation media produce more energetic GRBs. Spectral features in GRB spectra are, on average, 2.5 times stronger than those seen in QSO intervening damped Lyman-alpha (DLA) systems and slightly more ionised. In particular we find larger excess in the EW of CIV1549 relative to QSO DLAs, which could be related to an excess of Wolf-Rayet stars in the environments of GRBs. From the CoG fitting we obtain an average number of components in the absorption features of GRBs of 6.00(-1.25,+1.00). The most extreme ionisation ratios in our sample are found for GRBs with low neutral hydrogen column density, which could be related to ionisation by the GRB emission.Comment: 37 pages, 31 figures, 15 tables. Accepted for publication in Astonomy and Astrophysic

The QCD phase diagram at nonzero quark density

We determine the phase diagram of QCD on the \mu-T plane for small to moderate chemical potentials. Two transition lines are defined with two quantities, the chiral condensate and the strange quark number susceptibility. The calculations are carried out on N_t =6,8 and 10 lattices generated with a Symanzik improved gauge and stout-link improved 2+1 flavor staggered fermion action using physical quark masses. After carrying out the continuum extrapolation we find that both quantities result in a similar curvature of the transition line. Furthermore, our results indicate that in leading order the width of the transition region remains essentially the same as the chemical potential is increased.Comment: 12 pages, 6 figure