Bifurcations in the theory of current transfer to cathodes of dc discharges and observations of transitions between different modes

General scenarios of transitions between different spot patterns on electrodes of dc gas discharges and their relation to bifurcations of steady-state solutions are analyzed. In the case of cathodes of arc discharges, it is shown that any transition between different modes of current transfer is related to a bifurcation of steady-state solutions. In particular, transitions between diffuse and spot modes on axially symmetric cathodes, frequently observed in the experiment, represent an indication of the presence of pitchfork or fold bifurcations of steady-state solutions. Experimental observations of transitions on cathodes of dc glow microdischarges are analyzed and those potentially related to bifurcations of steady-state solutions are identified. The relevant bifurcations are investigated numerically and the computed patterns are found to conform to those observed in the course of the corresponding transitions in the experiment

Antimicrobial resistance in Portuguese swine production—2013 and 2014 Laboratory data

Antimicrobial resistance is a growing concern for both human and animal health, as well as the environment. Several countries established surveillance programs for antimicrobial use in animals and in Portugal we also have the PANRUAA, since 2014, that encourages antimicrobial use reduction in animals. As swine production is one of the food industries where the antimicrobial use deserves attention, we collected laboratory data from pig samples to obtain information on antimicrobial resistance in Portuguese swine production. Escherichia coli is an indicator bacteria of normal intestinal flora of swine and in this study, we used Escherichia coli isolates to analyze antimicrobial resistance. Our aim was to contribute to the knowledge of antimicrobial resistance frequencies in Portuguese swine farms. Seventy seven strains of E. coli were isolated from intestinal swabs or stools of swine with symptoms of enteric pathology. Those samples came from 26 different farms and antimicrobial resistance was evaluated according to CLSI guidelines, by diffusion disc method. All Escherichia coli strains were resistant to more than one antimicrobial. Lincomycin, Doxycycline, Amoxycillin, Ampicillin and Oxytetracycline were the antimicrobials with the highest frequency of resistant strains. The lowest frequencies of antimicrobials resitant strains were found for Neomycin, Gentamicin, Ceftiofur and Marbofloxacin. Comparing antimicrobials resistance frequencies from both years, we found a significant increase for Amoxycillin, Apramycin, Colistin, Oxytetracycline and Lincomycin - Spectinomycin. Our data supports other findings of high antimicrobial resistance for Tetracyclines and Penicillins in samples from Portuguese slaughters. The antibioresistance for these antimicrobials groups has also been reported in swine samples in other European countries. This study provides information that together with data from other Portuguese studies, potentiate the knowledge of the real state of antimicrobials resistance in swine production and the adjustment of the antimicrobials administration

Thermal entanglement witness for materials with variable local spin lengths

We show that the thermal entanglement in a spin system using only magnetic susceptibility measurements is restricted to the insulator materials. We develop a generalization of the thermal entanglement witness that allows us to get information about the system entanglement with variable local spin lengths that can be used experimentally in conductor or insulator materials. As an application, we study thermal entanglement for the half-filled Hubbard model for linear, square and cubic clusters. We note that it is the itinerancy of electrons that favors the entanglement. Our results suggest a weak dependence between entanglement and external spin freedom degrees.Comment: 4 pages, 3 figure

Special subgroups of regular semigroups

This work was partially supported by the Portuguese Foundation for Science and Technology through the grant UID/MAT/00297/2013 (CMA).Extending the notions of inverse transversal and associate subgroup, we consider a regular semigroup S with the property that there exists a subsemigroup T which contains, for each x∈S, a unique y such that both xy and yx are idempotent. Such a subsemigroup is necessarily a group which we call a special subgroup. Here we investigate regular semigroups with this property. In particular, we determine when the subset of perfect elements is a subsemigroup and describe its structure in naturally arising situations.PostprintPeer reviewe

Knowledge and attitude towards the gradual reduction of salt in bread – an online survey

Aim: Assess knowledge and attitude towards the gradual reduction of salt in bread and the potential impact on eating habits of children (6-18 years) and their families, as part as a Health Impact Assessment pilot study.N/