7,821 research outputs found
Multiresistant Salmonella enterica serovar 4,[5],12:i:- in Europe: a new pandemic strain?
A marked increase in the prevalence of S. enterica serovar 4,[5],12:i:- with resistance to ampicillin, streptomycin, sulphonamides and tetracyclines (R-type ASSuT) has been noted in food-borne infections and in pigs/pig meat in several European countries in the last ten years. One hundred and sixteen strains of S. enterica serovar 4,[5],12:i:- from humans, pigs and pig meat isolated in England and Wales, France, Germany, Italy, Poland, Spain and the Netherlands were further subtyped by phage typing, pulsed-field gel electrophoresis and multilocus variable number tandem repeat analysis to investigate the genetic relationship among strains. PCR was performed to identify the fljB flagellar gene and the genes encoding resistance to ampicillin, streptomycin, sulphonamides and tetracyclines. Class 1 and 2 integrase genes were also sought. Results indicate that genetically related serovar 4,[5],12:i:- strains of definitive phage types DT193 and DT120 with ampicillin, streptomycin, sulphonamide and tetracycline resistance encoded by blaTEM, strA-strB, sul2 and tet(B) have emerged in several European countries, with pigs the likely reservoir of infection. Control measures are urgently needed to reduce spread of infection to humans via the food chain and thereby prevent the possible pandemic spread of serovar 4,[5],12:i:- of R-type ASSuT as occurred with S. Typhimurium DT104 during the 1990s
USCID fourth international conference
Presented at the Role of irrigation and drainage in a sustainable future: USCID fourth international conference on irrigation and drainage on October 3-6, 2007 in Sacramento, California.Includes bibliographical references.Centre pivot irrigation systems are known for their irrigation distribution performance potential. Unfortunately the performance analysis of centre pivot irrigation systems is often restricted to the uniformity of distribution. Depending on the characteristics of the applied rainfall, a system designed for high uniformity does not guarantee a high application efficiency once the system is in operation. A method is proposed in the present paper to analyse the average rainfall depth of application and kinetic energy delivered to the soil by individual droplets all over the machine. The method requires water distribution profiles, the distribution of droplet size and velocity along the radius of coverage for any nozzle, and pressure and height of the emitter installed on the machine. Considering the number of nozzles and the range of pressure applied, there is the need for a method calculating: the emitter maximum radius of coverage, then the rainfall distribution profile, then the droplet distribution and finally the associated kinetic energy delivery. These parameters are calculated on a new model of classical design sprayers proposed by IWT Company. These results are being integrated on a centre pivot nozzle chart design software presented in the poster session
Experimental Studies of Prompt Fission Neutron Energy Spectra
AbstractPrompt fission neutron spectra were measured in the reactions 238U(n,f), 235U(n,f) and 237Np(n,f) at different incident neutron energies. The neutrons were detected using a coaxial doped p-terphenyl scintillation detector in coincidence with fission fragments and their time-of-flight was recorded. The properties of the neutron detector were determined and the results are presented in this work. A preliminary neutron detection efficiency was applied to data from the neutron-induced fission of 238U at En = 5.2 MeV, leading to encouraging results
Precision estimation and second-order prediction errors in cortical circuits
Minimization of cortical prediction errors is believed to be a key canonical
computation of the cerebral cortex underlying perception, action and learning.
However, it is still unclear how the cortex should form and use knowledge about
uncertainty in this process of prediction error minimization. Here we derive
neural dynamics minimizing prediction errors under the assumption that cortical
areas must not only predict the activity in other areas and sensory streams,
but also jointly estimate the precision of their predictions. This leads to a
dynamic modulatory balancing of cortical streams based on context-dependent
precision estimates. Moreover, the theory predicts the existence of
second-order prediction errors, i.e. errors on precision estimates, computed
and propagated through the cortical hierarchy alongside classical prediction
errors. These second-order errors are used to learn weights of synapses
responsible for precision estimation through an error-correcting synaptic
learning rule. Finally, we propose a mapping of the theory to cortical
circuitry
Cretaceous Roveacrinids from Mexico revisited: Overcoming the taxonomic misidentifications and subsequent biostratigraphic abuse
The Mesozoic carbonate deposits
of Mexico yield a number of overlooked,
ill-known, and even enigmatic
microfossils, among which are roveacrinoids
(Echinodermata, Crinoidea,
Roveacrinida). Most of these pelagic
organisms probably came from the
central Tethysian seaways, and later
on from the early central Atlantic
Ocean through the northwestern
Tethysian neck, thus reaching
the Central American platforms
(Comanchean shelf, Central Texas
platform, and Coahuila platform)
and the Western Interior seaway. The
present work intends to enlist as comprehensively
as possible the Mexican
records of roveacrinid crinoids, to
propose a revised interpretation of
the sections illustrated (most of them
being originally erroneously assigned)
and to provide a sound data base
for further systematic and biostratigraphic
research
Emerg. Infect. Dis
The multidrug-resistant (MDR) Salmonella enterica serotype Newport strain that produces CMY-2 β-lactamase(Newport MDR-AmpC) was the source of sporadic cases and outbreaks in humans in France during 2000–2005. Because this strain was not detected in food animals, it was most likely introduced into France through imported food products
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