198 research outputs found

    Canine hair follicular tumours: a retrospective study

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    Hair follicular tumours in dog comprise a large and heterogeneous group of neoplasms that display morphological features resembling one or several portions of the normal hair follicle which constitute a huge effort for its diagnosis. Histopathological evaluation is required to better characterize the different types of canine hair follicular tumours, in order to better understand its biological behaviour and to collaborate with the daily clinical practice. Thus, a retrospective, cross-sectional descriptive study was carried out with goal of analyse its frequency and characteristics, in order to contribute to a better understanding of this vast group of tumours. As main results the authors verified a higher incidence of follicular tumours in male dogs, being the most frequent types diagnosed trichoepithelioma, followed by, trichoblastoma, infundibular keratinizing acanthoma and pilomatricoma and the average age of dogs was 8.76 years. Also, malignant tumours represented 31.6% of all canine hair follicular tumours diagnosed (n= 114).info:eu-repo/semantics/publishedVersio

    Alignment of the ALICE Inner Tracking System with cosmic-ray tracks

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    37 pages, 15 figures, revised version, accepted by JINSTALICE (A Large Ion Collider Experiment) is the LHC (Large Hadron Collider) experiment devoted to investigating the strongly interacting matter created in nucleus-nucleus collisions at the LHC energies. The ALICE ITS, Inner Tracking System, consists of six cylindrical layers of silicon detectors with three different technologies; in the outward direction: two layers of pixel detectors, two layers each of drift, and strip detectors. The number of parameters to be determined in the spatial alignment of the 2198 sensor modules of the ITS is about 13,000. The target alignment precision is well below 10 micron in some cases (pixels). The sources of alignment information include survey measurements, and the reconstructed tracks from cosmic rays and from proton-proton collisions. The main track-based alignment method uses the Millepede global approach. An iterative local method was developed and used as well. We present the results obtained for the ITS alignment using about 10^5 charged tracks from cosmic rays that have been collected during summer 2008, with the ALICE solenoidal magnet switched off.Peer reviewe

    First measurement of the |t|-dependence of coherent J/ψ photonuclear production

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    The first measurement of the cross section for coherent J/ψ photoproduction as a function of |t|, the square of the momentum transferred between the incoming and outgoing target nucleus, is presented. The data were measured with the ALICE detector in ultra-peripheral Pb–Pb collisions at a centre-of-mass energy per nucleon pair sNN=5.02TeV with the J/ψ produced in the central rapidity region |y|<0.8, which corresponds to the small Bjorken-x range (0.3−1.4)×10−3. The measured |t|-dependence is not described by computations based only on the Pb nuclear form factor, while the photonuclear cross section is better reproduced by models including shadowing according to the leading-twist approximation, or gluon-saturation effects from the impact-parameter dependent Balitsky–Kovchegov equation. These new results are therefore a valid tool to constrain the relevant model parameters and to investigate the transverse gluonic structure at very low Bjorken-x.publishedVersio

    Resolving the strange behavior of extraterrestrial potassium in the upper atmosphere

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    It has been known since the 1960s that the layers of Na and K atoms, which occur between 80 and 105 km in the Earth's atmosphere as a result of meteoric ablation, exhibit completely different seasonal behavior. In the extratropics Na varies annually, with a pronounced wintertime maximum and summertime minimum. However, K varies semiannually with a small summertime maximum and minima at the equinoxes. This contrasting behavior has never been satisfactorily explained. Here we use a combination of electronic structure and chemical kinetic rate theory to determine two key differences in the chemistries of K and Na. First, the neutralization of K+ ions is only favored at low temperatures during summer. Second, cycling between K and its major neutral reservoir KHCO3 is essentially temperature independent. A whole atmosphere model incorporating this new chemistry, together with a meteor input function, now correctly predicts the seasonal behavior of the K layer

    A(c)(+) Production and Baryon-to-Meson Ratios in pp and p-Pb Collisions at root S-NN=5.02 TeV at the LHC

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    The prompt production of the charm baryon \u39bc+ and the \u39bc+/D0 production ratios were measured at midrapidity with the ALICE detector in pp and p-Pb collisions at sNN=5.02 TeV. These new measurements show a clear decrease of the \u39bc+/D0 ratio with increasing transverse momentum (pT) in both collision systems in the range 2<12 GeV/c, exhibiting similarities with the light-flavor baryon-to-meson ratios p/\u3c0 and \u39b/KS0. At low pT, predictions that include additional color-reconnection mechanisms beyond the leading-color approximation, assume the existence of additional higher-mass charm-baryon states, or include hadronization via coalescence can describe the data, while predictions driven by charm-quark fragmentation processes measured in e+e- and e-p collisions significantly underestimate the data. The results presented in this Letter provide significant evidence that the established assumption of universality (colliding-system independence) of parton-to-hadron fragmentation is not sufficient to describe charm-baryon production in hadronic collisions at LHC energies

    ALICE Collaboration

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    A(c)(+) Production and Baryon-to-Meson Ratios in pp and p-Pb Collisions at root S-NN=5.02 TeV at the LHC

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    The prompt production of the charm baryon Λ_{c}^{+} and the Λ_{c}^{+}/D^{0} production ratios were measured at midrapidity with the ALICE detector in pp and p-Pb collisions at sqrt[s_{NN}]=5.02  TeV. These new measurements show a clear decrease of the Λ_{c}^{+}/D^{0} ratio with increasing transverse momentum (p_{T}) in both collision systems in the range 2<p_{T}<12  GeV/c, exhibiting similarities with the light-flavor baryon-to-meson ratios p/π and Λ/K_{S}^{0}. At low p_{T}, predictions that include additional color-reconnection mechanisms beyond the leading-color approximation, assume the existence of additional higher-mass charm-baryon states, or include hadronization via coalescence can describe the data, while predictions driven by charm-quark fragmentation processes measured in e^{+}e^{-} and e^{-}p collisions significantly underestimate the data. The results presented in this Letter provide significant evidence that the established assumption of universality (colliding-system independence) of parton-to-hadron fragmentation is not sufficient to describe charm-baryon production in hadronic collisions at LHC energies

    Suppression in Pb-Pb Collisions at the LHC.

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    The production of the ψ(2S) charmonium state was measured with ALICE in Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV, in the dimuon decay channel. A significant signal was observed for the first time at LHC energies down to zero transverse momentum, at forward rapidity (2.5<y<4). The measurement of the ratio of the inclusive production cross sections of the ψ(2S) and J/ψ resonances is reported as a function of the centrality of the collisions and of transverse momentum, in the region p_{T}<12  GeV/c. The results are compared with the corresponding measurements in pp collisions, by forming the double ratio [σ^{ψ(2S)}/σ^{J/ψ}]_{Pb-Pb}/[σ^{ψ(2S)}/σ^{J/ψ}]_{pp}. It is found that in Pb-Pb collisions the ψ(2S) is suppressed by a factor of ∌2 with respect to the J/ψ. The ψ(2S) nuclear modification factor R_{AA} was also obtained as a function of both centrality and p_{T}. The results show that the ψ(2S) resonance yield is strongly suppressed in Pb-Pb collisions, by a factor of up to ∌3 with respect to pp. Comparisons of cross section ratios with previous Super Proton Synchrotron findings by the NA50 experiment and of R_{AA} with higher-p_{T} results at LHC energy are also reported. These results and the corresponding comparisons with calculations of transport and statistical models address questions on the presence and properties of charmonium states in the quark-gluon plasma formed in nuclear collisions at the LHC

    Characterization of histopathologic lesions in gastroenteritis associated to norovirus in a model of study

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    Background: Human noroviruses are the major cause of nonbacterial epidemic gastroenteritis worldwide. Although noroviruses have been absent from the list of gastrointestinal infectious agents in dogs, recently several studies emphasized their role in the aetiology of gastroenteritis, suggesting the possibility of a novel model for human infection. The aim of this study was to evaluate the histopathological lesions in gastroenteritis, associated to canine norovirus, in order to contribute to the knowledge of its pathogenic features and the role of apoptotic events in the noroviruses pathogenesis. Material and methods: Samples of small intestine were collected from 2 adult dogs (2-year-old cross-bred and a 6 year-old cocker spaniel) housed in a kennel where CaNoV had been diagnosed. Samples of small intestine were collected and fixed (10% neutral buffered formalin) for a maximum of 48 hours, dehydrated (graded ethanol series) and embedded in paraffin wax. Apoptosis studies combined the immunohistochemical detection of cytochrome c (anti-cytochrome C sc-8385 antibody, Santa Cruz Biotechnology) and the DNA fragmentation by TUNEL assay (In Situ Cell Death Detection Kit, Roche, Germany). Samples were examined by light microscopy (Microscope Zeiss Mod. Axioplan 2), by two independent observers. All procedures were performed in accordance with the European Communities Council Directive 86/609/ECC. Results: The microscopic findings revealed severe epithelial detachment, mucosal loss and hypertrophy of all small intestinal layers. Also, an intense mononuclear inflammatory infiltrate within lamina propria of small intestine proximal segments were seen, very similar to IBD lesional pattern. Discussion and Conclusions: Canine inflammatory bowel disease (IBD) is a heterogeneous group of chronic gastrointestinal disorders with unknown aetiology, immunologically-mediated, similar to human IBD. With this study it is tempting to hypothesize that canine norovirus could be significantly evolved in the complex aetiopathogenesis of IBD, identically in human Crohn disease - an example of human IBD, which could highlight the relevance of norovirus, in its role of in the aetiopathogenesis of this chronic condition
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