76 research outputs found
Unveiling SU(3) Flux Tubes At Nonzero Temperature: Electric Fields and Magnetic Currents
We report on the results of measuring the chromoelectric fields in a flux
tube created by a static quark-antiquark pair in the finite-temperature SU(3)
gauge theory. Below the deconfinement temperature the field behavior is similar
to the zero-temperature case. Above the deconfinement temperature the field
shape remains the same, but the field values drop when the distance between
quark and antiquark increases, thus showing the disappearance of confining
potential.Comment: 18 pages, 11 figures. arXiv admin note: text overlap with
arXiv:2207.0879
Biofilm production and antibiotic resistance of human and veterinary Staphylococcus strains.
Staphylococcus spp. is widely distributed in medical and veterinary pathology and represents one of the most important causes of infection. Many strains are antibiotic-resistant even for the presence of an eso-polysaccharide matrix. The aim of this work was to individuate, among 396 different Staphylococci of human and animal origin, the slime producing strains and to correlate the presence of biofilm to the resistance to eight antibiotics. A total of 185 coagulase negative staphylococci (CNS) and 211 S. aureus isolated from different sources and identified with Sceptor System, were tested for antibiotic susceptibility (Kirby Bauer method) and for slime production (Polystyrene plates – stained with Alcian blue – Spectrophotometric reading at 450 nm). The strains were classified as weak, strong and no slime-producing on the basis of OD results. The results were submitted to statistical analysis using Student’s t-test and chi-square tests. Evaluating the differences of slime production among medical and veterinary strains, we found different statistical frequencies (P > 0.001). No statistical differences wereobtained between S. aureus and the other CNS. Instead, the statistical analysis on S. epidermidis vs. the other staphylococci has shown no statistical differences among average values using Student’s ttest (P < 0.052) and significant frequency differences using chi square tests (P < 0.02). Finally in the CNS, between S. epidermidis and the other strains, no statistical differences were found. The relation between slime production and the origin of strains was evaluated and no correlation was found. About the correlation between antibiotic-resistance and slime production a resistance increment of about 30% was obtained in strongly slime producing strains. Staphylococcus spp. is often involved in nosocomial infections as complication of post-surgery wounds, catheters and orthopaedic devices. The presence of antibiotic-resistant strains interferes in the therapy successes and seems to be strictly related to biofilm production beyond that genetically acquired. Human and veterinary strains have shown a similar behaviour towards biofilm production and antibiotic-resistance. The results confirm that S. epidermidis is one of the most slime-producer and introduce S. aureus as a new high slime-producer
Thermal QCD in a non-uniform magnetic background
Off-central heavy-ion collisions are known to feature magnetic fields with
magnitudes and characteristic gradients corresponding to the scale of the
strong interactions. In this work, we employ equilibrium lattice simulations of
the underlying theory, QCD, involving similar inhomogeneous magnetic field
profiles to achieve a better understanding of this system. We simulate three
flavors of dynamical staggered quarks with physical masses at a range of
magnetic fields and temperatures, and extrapolate the results to the continuum
limit. Analyzing the impact of the field on the quark condensate and the
Polyakov loop, we find non-trivial spatial features that render the QCD medium
qualitatively different as in the homogeneous setup, especially at temperatures
around the transition. In addition, we construct leading-order chiral
perturbation theory for the inhomogeneous background and compare its prediction
to our lattice results at low temperature. Our findings will be useful to
benchmark effective theories and low-energy models of QCD for a better
description of peripheral heavy-ion collisions.Comment: 24 pages, 15 figure
Identificazione mediante PCR dei plasmidi di virulenza di Rhodococcus equi isolati da cavalli in Italia.
Analysis of the antibiotic resistance profiles in methicillin-sensitive s. Aureus pathotypes isolated on a commercial rabbit farm in Italy
The breeding of meat rabbits is an important sector in the livestock industry in Italy. The focus of this study was to describe the antibiotic resistance profile distribution among the Methicillin-sensitive Staphylococcus aureus isolated in a rabbit farm. From 400 animals of different ages and three farm workers, 96 randomly selected strains isolated from various anatomical sites and lesions were analysed. According to spa typing and the resistance profiles towards veterinary and human antibiotics, 26 pathotypes were identified. The highest resistance was observed against Tetracyclines (92.3%) and Macrolides (80.8%), while almost all were susceptible to Penicillins, according to the limited use of β-lactams on the farm. In total, 92.3% of pathotypes were multidrug resistant (MDRs). Two MDR pathotypes belonging to the t2802 spa type were isolated from both farmers and rabbits. Age categories harboured significantly different pathotypes (p = 0.019), while no association was found between pathotypes and lesions (p = 0.128) or sampling sites (p = 0.491). The antibiotic resistance was observed to increase with the time spent in the farm environment (age category). The selective pressure exerted by antibiotic use acted by giving advantage to more resistant strains rather than by lowering susceptibility to various drug categories within strains
Visna-Maedi: indagine sierologica mediante test immunoenzimatico utilizzando un antigene sintetico.
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