3,217 research outputs found
Genetic variability of Haemonchus contortus (Nematoda: Trichostrongyloidea) in alpine ruminant host species
Genetic variability of the ovine parasite Haemonchus contortus from the Alpine area was investigated using mitochondrial DNA (nd4 gene), internal transcribed spacers 1 and 2 and microsatellites, in order to assess whether cross-transmission between domestic and wild ruminants occurs. The dataset was composed of 78 individual adult male H. contortus collected from chamois (Rupicapra r. rupicapra), roe deer (Capreolus capreolus), alpine ibex (Capra ibex ibex), domestic goat (Capra hircus) and sheep (Ovis aries) from different alpine areas. The data obtained show low host specificity and high genetic variation within H. contortus populations. The analyses indicate the presence of two mitochondrial haplotype clusters among host species and the absence of cryptic parasite species, confirming H. contortus as a generalist nematode and suggesting that parasite transmission between populations of domestic and wild ruminants normally occurs
The imaging properties of the Gas Pixel Detector as a focal plane polarimeter
X-rays are particularly suited to probe the physics of extreme objects.
However, despite the enormous improvements of X-ray Astronomy in imaging,
spectroscopy and timing, polarimetry remains largely unexplored. We propose the
photoelectric polarimeter Gas Pixel Detector (GPD) as an instrument candidate
to fill the gap of more than thirty years of lack of measurements. The GPD, in
the focus of a telescope, will increase the sensitivity of orders of magnitude.
Moreover, since it can measure the energy, the position, the arrival time and
the polarization angle of every single photon, allows to perform polarimetry of
subsets of data singled out from the spectrum, the light curve or the image of
source. The GPD has an intrinsic very fine imaging capability and in this work
we report on the calibration campaign carried out in 2012 at the PANTER X-ray
test facility of the Max-Planck-Institut f\"ur extraterrestrische Physik of
Garching (Germany) in which, for the first time, we coupled it to a JET-X
optics module with a focal length of 3.5 m and an angular resolution of 18
arcsec at 4.5 keV. This configuration was proposed in 2012 aboard the X-ray
Imaging Polarimetry Explorer (XIPE) in response to the ESA call for a small
mission. We derived the imaging and polarimetric performance for extended
sources like Pulsar Wind Nebulae and Supernova Remnants as case studies for the
XIPE configuration, discussing also possible improvements by coupling the
detector with advanced optics, having finer angular resolution and larger
effective area, to study with more details extended objects.Comment: Accepted for publication in The Astrophysical Journal Supplemen
The in-flight spectroscopic performance of the Swift XRT CCD camera during 2006-2007
The Swift X-ray Telescope focal plane camera is a front-illuminated MOS CCD,
providing a spectral response kernel of 135 eV FWHM at 5.9 keV as measured
before launch. We describe the CCD calibration program based on celestial and
on-board calibration sources, relevant in-flight experiences, and developments
in the CCD response model. We illustrate how the revised response model
describes the calibration sources well. Comparison of observed spectra with
models folded through the instrument response produces negative residuals
around and below the Oxygen edge. We discuss several possible causes for such
residuals. Traps created by proton damage on the CCD increase the charge
transfer inefficiency (CTI) over time. We describe the evolution of the CTI
since the launch and its effect on the CCD spectral resolution and the gain.Comment: 8 pages, 5 colour figures, submitted to SPI
Erythromycin-resistant lactic acid bacteria in the healthy gut of vegans, ovo-lacto vegetarians and omnivores
Diet can affect the diversity and composition of gut microbiota. Usage of antibiotics in food production and in human or veterinary medicine has resulted in the emergence of commensal antibiotic resistant bacteria in the human gut. The incidence of erythromycin-resistant lactic acid bacteria (LAB) in the feces of healthy vegans, ovo-lacto vegetarians and omnivores was analyzed. Overall, 155 LAB were isolated and characterized for their phenotypic and genotypic resistance to erythromycin. The isolates belonged to 11 different species within the Enterococcus and Streptococcus genera. Enterococcus faecium was the dominant species in isolates from all the dietary categories. Only 97 out of 155 isolates were resistant to erythromycin after Minimum Inhibitory Concentration (MIC) determination; among them, 19 isolates (7 from vegans, 4 from ovo-lacto vegetarians and 8 from omnivores) carried the erm(B) gene. The copresence of erm(B) and erm(A) genes was only observed in Enterococcus avium from omnivores. Moreover, the transferability of erythromycin resistance genes using multidrug-resistant (MDR) cultures selected from the three groups was assessed, and four out of six isolates were able to transfer the erm(B) gene. Overall, isolates obtained from the omnivore samples showed resistance to a greater number of antibiotics and carried more tested antibiotic resistance genes compared to the isolates from ovo-lacto vegetarians and vegans. In conclusion, our results show that diet does not significantly affect the occurrence of erythromycin-resistant bacteria and that commensal strains may act as a reservoir of antibiotic resistance (AR) genes and as a source of antibiotic resistance spreading
Erythromycin-resistant lactic acid bacteria in the healthy gut of vegans, ovo-lacto vegetarians and omnivores
Diet can affect the diversity and composition of gut microbiota. Usage of antibiotics in food production and in human or veterinary medicine has resulted in the emergence of commensal antibiotic resistant bacteria in the human gut. The incidence of erythromycin-resistant lactic acid bacteria (LAB) in the feces of healthy vegans, ovo-lacto vegetarians and omnivores was analyzed. Overall, 155 LAB were isolated and characterized for their phenotypic and genotypic resistance to erythromycin. The isolates belonged to 11 different species within the Enterococcus and Streptococcus genera. Enterococcus faecium was the dominant species in isolates from all the dietary categories. Only 97 out of 155 isolates were resistant to erythromycin after Minimum Inhibitory Concentration (MIC) determination; among them, 19 isolates (7 from vegans, 4 from ovo-lacto vegetarians and 8 from omnivores) carried the erm(B) gene. The copresence of erm(B) and erm(A) genes was only observed in Enterococcus avium from omnivores. Moreover, the transferability of erythromycin resistance genes using multidrug-resistant (MDR) cultures selected from the three groups was assessed, and four out of six isolates were able to transfer the erm(B) gene. Overall, isolates obtained from the omnivore samples showed resistance to a greater number of antibiotics and carried more tested antibiotic resistance genes compared to the isolates from ovo-lacto vegetarians and vegans. In conclusion, our results show that diet does not significantly affect the occurrence of erythromycin-resistant bacteria and that commensal strains may act as a reservoir of antibiotic resistance (AR) genes and as a source of antibiotic resistance spreading
Competing risk analysis on outcome after hepatic resection of hepatocellular carcinoma in cirrhotic patients
To investigate death for liver failure and for tumor recurrence as competing events after hepatectomy of hepatocellular carcinoma. METHODS Data from 864 cirrhotic Child-Pugh class A consecutive patients, submitted to curative hepatectomy (1997-2013) at two tertiary referral hospitals, were used for competing-risk analysis through the Fine and Gray method, aimed at assessing in which circumstances the oncological benefit from tumour removal is greater than the risk of dying from hepatic decompensation. To accomplish this task, the average risk of these two competing events, over 5 years of follow-up, was calculated through the integral of each cumulative incidence function, and represented the main comparison parameter. RESULTS Within a median follow-up of 5.6 years, death was attributable to tumor recurrence in 63.5%, and to liver failure in 21.2% of cases. In the first 16 mo, the risk of dying due to liver failure exceeded that of dying due to tumor relapse. Tumor stage only affects death from recurrence; whereas hepatitis C infection, Model for End-stage Liver Disease score, extent of hepatectomy and portal hypertension influence death from liver failure (P < 0.05 in all cases). The combination of these clinical and tumoral features identifies those patients in whom the risk of dying from liver failure did not exceed the tumour-related mortality, representing optimal surgical candidates. It also identifies those clinical circumstances where the oncological benefit would be borderline or even where the surgery would be harmful. CONCLUSION Having knowledge of these competing events can be used to weigh the risks and benefits of hepatic resection in each clinical circumstance, separating optimal from non-optimal surgical candidates
Hadron Energy Reconstruction for the ATLAS Calorimetry in the Framework of the Non-parametrical Method
This paper discusses hadron energy reconstruction for the ATLAS barrel
prototype combined calorimeter (consisting of a lead-liquid argon
electromagnetic part and an iron-scintillator hadronic part) in the framework
of the non-parametrical method. The non-parametrical method utilizes only the
known ratios and the electron calibration constants and does not require
the determination of any parameters by a minimization technique. Thus, this
technique lends itself to an easy use in a first level trigger. The
reconstructed mean values of the hadron energies are within of the
true values and the fractional energy resolution is . The value of the ratio
obtained for the electromagnetic compartment of the combined calorimeter is
and agrees with the prediction that for this
electromagnetic calorimeter. Results of a study of the longitudinal hadronic
shower development are also presented. The data have been taken in the H8 beam
line of the CERN SPS using pions of energies from 10 to 300 GeV.Comment: 33 pages, 13 figures, Will be published in NIM
A highly endemic area of Echinococcus multilocularis identified through a comparative re-assessment of prevalence in the red fox (Vulpes vulpes), Alto Adige (Italy: 2019-2020)
Surveillance of Echinococcus multilocularis at the edge of its range is hindered by fragmented distributional patterns and low prevalence in definitive hosts. Thus, tests with adequate levels of sensitivity are especially important for discriminating between infected and non-infected areas. In this study we reassessed the prevalence of E. multilocularis at the southern border of its distribution in Province of Bolzano (Alto Adige, northeastern Alps, Italy), to improve surveillance in wildlife and provide more accurate estimates of exposure risk. We compared the diagnostic test currently implemented for surveillance based on coproscopy and multiplex PCR (CMPCR) to a real-time quantitative PCR (qPCR) in 235 fox faeces collected in 2019 and 2020. The performances of the two tests were estimated using a scraping technique (SFCT) applied to the small intestines of a subsample (n = 123) of the same foxes as the reference standard. True prevalence was calculated and the sample size required by each faecal test for the detection of the parasite was then estimated. True prevalence of E. multilocularis in foxes (14.3%) was markedly higher than reported in the last decade, which was never more than 5% from 2012 to 2018 in the same area. In addition, qPCR showed a much higher sensitivity (83%) compared to CMPCR (21%) and agreement with the reference standard was far higher for qPCR (0.816) than CMPCR (0.298) meaning that for the latter protocol, a smaller sample size would be required to detect the disease. Alto Adige should be considered a highly endemic area. Routine surveillance on definitive hosts at the edges of the E. multilocularis distribution should be applied to smaller geographic areas, and rapid, sensitive diagnostic tools using directly host faeces, such as qPCR, should be adopted
Characteristics and performance of the Swift X-Ray telescope
The X-ray Telescope (XRT), on board the Swift satellite, has been built to provide: automated source detection and position with few arcsecond accuracy within 5 seconds of target acquisition; CCD spectroscopy and imaging capability
(0.2â10 keV), with a detection sensitivity of 2 Ă 10â14 erg cmâ2 sâ1 in 104 s; automatic adjusting of the CCD readout mode to optimize the science return as the source fades. XRT can observe GRB afterglows over several orders of magnitude in flux. The first results obtained during the
in-flight performance verification phase confirm that XRT is fully compliant with the requirements and is providing excellent results
- âŠ