8 research outputs found
High Energy Neutrinos and Photons from Curvature Pions in Magnetars
We discuss the relevance of the curvature radiation of pions in strongly
magnetized pulsars or magnetars, and their implications for the production of
TeV energy neutrinos detectable by cubic kilometer scale detectors, as well as
high energy photons.Comment: 19 pages, 4 figures, to appear in JCA
The order of the quantum chromodynamics transition predicted by the standard model of particle physics
We determine the nature of the QCD transition using lattice calculations for
physical quark masses. Susceptibilities are extrapolated to vanishing lattice
spacing for three physical volumes, the smallest and largest of which differ by
a factor of five. This ensures that a true transition should result in a
dramatic increase of the susceptibilities.No such behaviour is observed: our
finite-size scaling analysis shows that the finite-temperature QCD transition
in the hot early Universe was not a real phase transition, but an analytic
crossover (involving a rapid change, as opposed to a jump, as the temperature
varied). As such, it will be difficult to find experimental evidence of this
transition from astronomical observations.Comment: 7 pages, 4 figure
The isolation of verocytotoxin-producing Escherichia coli (VTEC) strains from improperly pasteurised cow’s milk samples
The authors investigated the possibility of the presence of VTEC strains in improperly pasteurized milk samples. A total of 64 Escherichia coli strains were isolated from 135 pasteurized milk samples originating from the same producer. The examined isolates contained 29 haemolysin-, 9 colicin- and 5 aerobactin-producing strains, but the investigations concerning heat-resistant and heat-sensitive toxins gave negative results.Six O128-type E. coli strains exerted a cytotoxic effect on the VERO cell line; 5 of them contained H12 antigen, while one could not be typed. Four of the 6 verocytotoxin-producing strains belonged in phage group 20, one in phage group (2)3(7), and one in phage group 4; four strains were of B3, one of A1, and one of A1(A2) phage type.Because of a technical failure the milk was pasteurized at 69 °C for 15 s, which is 2 °C less than required. The results underline the importance of the appropriate pasteurization temperature, as otherwise the milk may contain verocytotoxin-producing E. coli, which is a potentially great hazard for public health
Global phylogeography and evolutionary history of Shigella dysenteriae type 1.
International audienceTogether with plague, smallpox and typhus, epidemics of dysentery have been a major scourge of human populations for centuries(1). A previous genomic study concluded that Shigella dysenteriae type 1 (Sd1), the epidemic dysentery bacillus, emerged and spread worldwide after the First World War, with no clear pattern of transmission(2). This is not consistent with the massive cyclic dysentery epidemics reported in Europe during the eighteenth and nineteenth centuries(1,3,4) and the first isolation of Sd1 in Japan in 1897(5). Here, we report a whole-genome analysis of 331 Sd1 isolates from around the world, collected between 1915 and 2011, providing us with unprecedented insight into the historical spread of this pathogen. We show here that Sd1 has existed since at least the eighteenth century and that it swept the globe at the end of the nineteenth century, diversifying into distinct lineages associated with the First World War, Second World War and various conflicts or natural disasters across Africa, Asia and Central America. We also provide a unique historical perspective on the evolution of antibiotic resistance over a 100-year period, beginning decades before the antibiotic era, and identify a prevalent multiple antibiotic-resistant lineage in South Asia that was transmitted in several waves to Africa, where it caused severe outbreaks of disease