12,788 research outputs found
Anti Microbial Resistance Profile of E. coli isolates From Tropical Free Range Chickens
Normal intestinal flora of humans and animals constitute enormous reservoir of resistance genes for potentially pathogenic bacteria and may serve as major indictors of selection pressure exerted by anti-microbial use in a given population. A study was conducted in September 2003 at 3 purposively selected peri-urban sites spread across 3 senatorial zones of Imo state, Nigeria to determines the anti-microbial resistance profile of commensal E. coli isolated from free range chickens. The isolates were screened for anti-microbial resistance profile against 10 antibiotics using the disc diffusion method. E. coli strains from local fowls, recorded 100 and 78.9% resistances against ampicillin and cotrimoxazole respectively, while resistance rates against ciprofloxacin, gentamycin and norfloxacin were 0.0, 5.3 and 5.3% respectively. Isolates from free-range cockerels recorded 100% resistance against norfloxacin, cotrimoxazole and ampicillin and 83.3% against nitrofurantoin. Similarly, isolates from old layers, recorded 100% resistance against nitrofurantoin, cotrimoxazole, tetracycline, chloramphenicol and ampicillin and 80% against nalidixic acid. Similar resistance trends were observed in E. coli isolates from free-range turkeys and broiler roosters against the inexpensive broad-spectrum first line antibiotics (ampicillin, nalidixic acid, cotrimoxazole, nitrofurantoin and chloramphenicol), although values varied slightly across poultry types. Resistances against gentamycin were consistently low in isolates from the different types of poultry. Twenty-nine resistance patterns were observed in the E. coli isolates with predominant patterns being distributed widely across poultry types indicating a striking diversity of resistance patterns in the areas
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Refinement and preliminary evaluation of two tablet-based tests of real-world visual function
PURPOSE: To describe, refine, evaluate, and provide normative control data for two freely available tablet-based tests of real-world visual function, using a cohort of young, normally-sighted adults.
METHODS: Fifty young (18-40Â years), normally-sighted adults completed tablet-based assessments of (1) face discrimination and (2) visual search. Each test was performed twice, to assess test-retest repeatability. Post-hoc analyses were performed to determine the number of trials required to obtain stable estimates of performance. Distributions were fitted to the normative data to determine the 99% population-boundary for normally sighted observers. Participants were also asked to rate their comprehension of each test.
RESULTS: Both tests provided stable estimates in around 20 trials (~1-4Â min), with only a further reduction of 14%-17% in the 95% Coefficient of Repeatability (CoR95 ) when an additional 40 trials were included. When using only ~20 trials: median durations for the first run of each test were 191Â s (Faces) and 51Â s (Search); test-retest CoR95 were 0.27Â d (Faces) and 0.84Â s (Search); and normative 99% population-limits were 3.50Â d (Faces) and 3.1Â s (Search). No participants exhibited any difficulties completing either test (100% completion rate), and ratings of task-understanding were high (Faces: 9.6 out of 10; Search: 9.7 out of 10).
CONCLUSIONS: This preliminary assessment indicated that both tablet-based tests are able to provide simple, quick, and easy-to-administer measures of real-world visual function in normally-sighted young adults. Further work is required to assess their accuracy and utility in older people and individuals with visual impairment. Potential applications are discussed, including their use in clinic waiting rooms, and as an objective complement to Patient Reported Outcome Measures (PROMs)
Min-oscillations in Escherichia coli induced by interactions of membrane-bound proteins
During division it is of primary importance for a cell to correctly determine
the site of cleavage. The bacterium Escherichia coli divides in the center,
producing two daughter cells of equal size. Selection of the center as the
correct division site is in part achieved by the Min-proteins. They oscillate
between the two cell poles and thereby prevent division at these locations.
Here, a phenomenological description for these oscillations is presented, where
lateral interactions between proteins on the cell membrane play a key role.
Solutions to the dynamic equations are compared to experimental findings. In
particular, the temporal period of the oscillations is measured as a function
of the cell length and found to be compatible with the theoretical prediction.Comment: 17 pages, 5 figures. Submitted to Physical Biolog
Nouveau découpage de la zone de forêt dense humide de la Côte d’Ivoire
Les cartes de la végétation connues sur la Côte d’Ivoire sont essentiellement basées sur la physionomie de la végétation. Dans le présent travail, nous sommes partis d’une base de données floristiques récapitulant toutes les informations botaniques disponibles sur la Côte d’Ivoire, de 1882 à 2006, et riche de 46.646 saisies relatives aux taxons végétaux vasculaires de la zone de forêt dense humide ivoirienne pour établir un découpage de ladite zone. L’intégration de ces taxons et les paramètres éco-géographiques dans une analyse canonique de correspondance nous a permis d’identifier cinq principaux faciès de forêt dense humide dont quatre sont de basses altitudes. Le déterminisme de ces principaux faciès est soit géologique, soit pédologique, soit climatique, soit à la fois pédoclimatiques.Mots clé : zone de forêt de dense, principaux faciès, déterminisme, Côte d’Ivoir
Direct Hiyama Cross-Coupling of Enaminones With Triethoxy(aryl)silanes and Dimethylphenylsilanol
2,3-Dihydropyridin-4(1H)-ones undergo direct C–H functionalization at C5 in the palladium(II)-catalyzed Hiyama reaction, using triethoxy(aryl)silanes and dimethylphenylsilanol. The reagent CuF2 has a dual role in the reactions with triethoxy(aryl)silanes. It is a source of fluoride to activate the silane in the Hiyama reaction and also serves as the reoxidant to convert Pd(0) to Pd(II) in the catalytic cycle
Cosmic ray spectral hardening due to dispersion in the source injection spectra
Recent cosmic ray (CR) experiments discovered that the CR spectra experience
a remarkable hardening for rigidity above several hundred GV. We propose that
this is caused by the superposition of the CR energy spectra of many sources
that have a dispersion in the injection spectral indices. Adopting similar
parameters as those of supernova remnants derived from the Fermi -ray
observations, we can reproduce the observational CR spectra of different
species well. This may be interpreted as evidence to support the supernova
remnant origin of CRs below the knee. We further propose that the same
mechanism may explain the "ankle" of the ultra high energy CR spectrum.Comment: 5 pages, 3 figures and 1 table. Updated with the diffusion
propagation model, accepted by Phys. Rev.
Excitonic ferromagnetism in the hexaborides
A ferromagnet with a small spontaneous moment but with a high Curie
temperature can be obtained by doping an excitonic insulator made from a spin
triplet exciton condensate. Such a condensate can occur in a semimetal with a
small overlap or a semiconductor with a small bandgap. We propose that it is
responsible for the unexpected ferromagnetism in the doped hexaboride material
Ca_{1-x}La_xB_6.Comment: 4 pages, 3 figure
Solar-type Stars Observed by LAMOST and Kepler
Obtaining measurements of chromospheric and photometric activity of stars
with near-solar fundamental parameters and rotation periods is important for a
better understanding of solar-stellar connection. We select a sample of 2603
stars with near-solar fundamental parameters from the Large Sky Area
Multi-Object Fiber Spectroscopic Telescope (LAMOST)-Kepler field and use LAMOST
spectra to measure their chromospheric activity and Kepler light curves to
measure their photospheric activity (i.e., the amplitude of the photometric
variability). While the rotation periods of 1556 of these stars could not be
measured due to the low amplitude of the photometric variability and highly
irregular temporal profile of light curves, 254 stars were further identified
as having near-solar rotation periods. We show that stars with near-solar
rotation periods have chromospheric activities that are systematically higher
than stars with undetected rotation periods. Furthermore, while the solar level
of photospheric and chromospheric activity appears to be typical for stars with
undetected rotation periods, the Sun appears to be less active than most stars
with near-solar rotation periods (both in terms of photospheric and
chromospheric activity).Comment: 7 pages, 6 figure
VetoMed : Un système expert à base d’icônes pour la médecine vétérinaire traditionnelle
Ce travail propose l’utilisation d’icônes pour représenter les faits dans un système expert, en remplacement du contenu textuel. Un générateur de systèmes experts basé sur l’utilisation d’icônes a été conçu et développé à cet effet. Il a permis de créer le système expert VetoMed dans le domaine de la pharmacopée traditionnelle vétérinaire où les acteurs sont souvent analphabètes. Grâce à son interface iconique adaptée aux utilisateurs illettrés, ce système permet à tout utilisateur de s’affranchir de tout intermédiaire pour la gestion et l’utilisation de sa base de connaissances.Mots-clés : système expert, générateur de systèmes expert, base de connaissances, médecine traditionnelle vétérinaire, plantes médicinales, interface iconique, tradipraticie
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