43 research outputs found

    Flux Creep and Flux Jumping

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    We consider the flux jump instability of the Bean's critical state arising in the flux creep regime in type-II superconductors. We find the flux jump field, BjB_j, that determines the superconducting state stability criterion. We calculate the dependence of BjB_j on the external magnetic field ramp rate, B˙e\dot B_e. We demonstrate that under the conditions typical for most of the magnetization experiments the slope of the current-voltage curve in the flux creep regime determines the stability of the Bean's critical state, {\it i.e.}, the value of BjB_j. We show that a flux jump can be preceded by the magneto-thermal oscillations and find the frequency of these oscillations as a function of B˙e\dot B_e.Comment: 7 pages, ReVTeX, 2 figures attached as postscript file

    Visual Analytics of Surveillance Data on Foodborne Vibriosis, United States, 1973–2010

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    Foodborne illnesses caused by microbial and chemical contaminants in food are a substantial health burden worldwide. In 2007, human vibriosis (non-cholera Vibrio infections) became a notifiable disease in the United States. In addition, Vibrio species are among the 31 major known pathogens transmitted through food in the United States. Diverse surveillance systems for foodborne pathogens also track outbreaks, illnesses, hospitalization and deaths due to non-cholera vibrios. Considering the recognition of vibriosis as a notifiable disease in the United States and the availability of diverse surveillance systems, there is a need for the development of easily deployed visualization and analysis approaches that can combine diverse data sources in an interactive manner. Current efforts to address this need are still limited. Visual analytics is an iterative process conducted via visual interfaces that involves collecting information, data preprocessing, knowledge representation, interaction, and decision making. We have utilized public domain outbreak and surveillance data sources covering 1973 to 2010, as well as visual analytics software to demonstrate integrated and interactive visualizations of data on foodborne outbreaks and surveillance of Vibrio species. Through the data visualization, we were able to identify unique patterns and/or novel relationships within and across datasets regarding (i) causative agent; (ii) foodborne outbreaks and illness per state; (iii) location of infection; (iv) vehicle (food) of infection; (v) anatomical site of isolation of Vibrio species; (vi) patients and complications of vibriosis; (vii) incidence of laboratory-confirmed vibriosis and V. parahaemolyticus outbreaks. The additional use of emerging visual analytics approaches for interaction with data on vibriosis, including non-foodborne related disease, can guide disease control and prevention as well as ongoing outbreak investigations

    Microbial quality of industrial and retail market grated parmesan cheese in the State of São Paulo, Brazil

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    ABSTRACT: With the objective to evaluate the hygienic and sanitary conditions of grated parmesan cheese acquired from the retail business, total 120 cheese samples were acquired: 60 of which were obtained from four different brands of cheese that were grated in factories, and the other 60 samples were obtained from another four brands of cheese that are normally acquired by retailers (supermarkets) in blocks and grated at the moment of sale. The population of heterotrophic mesophilic microorganisms ranged from 1.2×10³ to 1.1×107 colony-forming units (CFU)·g-1. All samples analyzed contained Staphylococcus spp. with populations varying from 1.2×10³ to 8.7×106CFU·g-1, from which 60.0% were classified as coagulase-positive Staphylococcus and 52.5% of the samples possessed populations above the permissible limit set by legislation. Staphylococcus aureus was detected in 57.5% of the samples. Population of molds and yeasts varied from <10 to 1.8×106CFU·g-1. Salmonella spp. was not isolated in this research. A difference was observed between the parmesan cheese grated in factories and that grated in supermarkets, where the former presented better microbiological quality than the latter. Thus, procedures must be proposed to minimize the presence of pathogenic agents reported in grated parmesan cheeses evaluated in the present study because of the public health risk associated with food bacterial contamination
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