453 research outputs found
Detection of serum antibodies to hepatitis E virus in domestic pigs in Italy using a recombinant swine HEV capsid protein
Background: The hepatitis E virus (HEV) has been detected in both humans and animals, particularly pigs, worldwide. Several evidences, including human infection following consumption of raw contaminated meat, suggest a zoonotic transmission of HEV. In Italy, large circulation of genotype 3 HEV has been reported in swine, and recent studies have confirmed the involvement of this genotype in autochthonous human cases.
Result: In this study 111 sera collected from healthy pigs in two Italian regions were tested for anti-HEV IgG antibodies. For specific HEV antibody detection in swine, we developed ELISA and Western blotting methods, using a truncated capsid (ORF2) protein lacking the first 111 amino acids of a swine HEV genotype 3 strain. The ORF2-based ELISA revealed anti-HEV antibodies in 104 out of 111 pigs compared with 102 detected with a commercial ELISA kit. A lower number of sera reacted with the recombinant ORF2 protein in a Western blotting format (81/111). Using a Latent class analysis (LCA),
the estimated sensitivities for ELISA-ORF2 and ELISA-kit tests were 0.961 and 0.936, respectively, whereas specificities were 0.599 and 0.475. The estimated sensitivity of Western blotting was 0.775, and the specificity was 0.944.
Conclusions: The overall results confirm the high prevalence of HEV seropositive healthy pigs in Italy. Through comparisons with a commercial ELISA test, the swine genotype 3 HEV antigen produced in this study was proven suitable to detect anti-HEV antibodies in pig sera by both ELISA and Western Blotting
Prevalence of hepatitis E virus in Italian pig herds. Preliminary results
Hepatitis E virus (HEV) is the causative agent of hepatitis E, and is an unenveloped positive sense single-stranded RNA wus. Swine HEV strains are genetically closely related to human strains from the same area, suggesting the occurrence of zoonotic transmission. Recently, human cases of hepatitis E have been linked to the consumption of raw or undercooked meat or organs from deer, wild boars or p1gs. The disease is now considered an emerging food-borne transmitted zoonosis. During 2006, a pilot investigation was performed to determine the prevalence of HEV in pig farms located in Northern Italy. 274 faecal samples were collected from healthy fattening animals (3-4 and 8-9 months of age) and from healthy breeding animals (gilts and sows) from 6 different farms, and analyzed using a Nested-RT-PCR targeting the open reading frame 2 (ORF2) region. Stool samples were suspended in water, and viral RNA extraction was performed using a commercial kit. Extracted viral RNA was subjected to RT-PCR amplification using degenerate primers conA 1-conS1 for the first amplification, and degenerate primers conA2-conS2 for the nested PCR, yielding a final fragment of 145 bp. HEV RNA was detected in sixty-nine of the 274 (25.2%) examined samples. None of the six farms resulted negative and the prevalence within the farms ranged between 2% and 60.5% For the characterization of the strains, randomly selected positive samples were subjected to nucleotide sequencing, and aligned with those present in the NCBI Data Bank Sequence analysis showed that all stra1ns were Swine Hepatitis E belonging to Genotype 3. These preliminary results confirm that swine HEV is widespread in Italian swine farms
The large cosmological constant approximation to classical and quantum gravity: model examples
We have recently introduced an approach for studying perturbatively classical
and quantum canonical general relativity. The perturbative technique appears to
preserve many of the attractive features of the non-perturbative quantization
approach based on Ashtekar's new variables and spin networks. With this
approach one can find perturbatively classical observables (quantities that
have vanishing Poisson brackets with the constraints) and quantum states
(states that are annihilated by the quantum constraints). The relative ease
with which the technique appears to deal with these traditionally hard problems
opens several questions about how relevant the results produced can possibly
be. Among the questions is the issue of how useful are results for large values
of the cosmological constant and how the approach can deal with several
pathologies that are expected to be present in the canonical approach to
quantum gravity. With the aim of clarifying these points, and to make our
construction as explicit as possible, we study its application in several
simple models. We consider Bianchi cosmologies, the asymmetric top, the coupled
harmonic oscillators with constant energy density and a simple quantum
mechanical system with two Hamiltonian constraints. We find that the technique
satisfactorily deals with the pathologies of these models and offers promise
for finding (at least some) results even for small values of the cosmological
constant. Finally, we briefly sketch how the method would operate in the full
four dimensional quantum general relativity case.Comment: 21 pages, RevTex, 2 figures with epsfi
Torque Teno Sus Virus (TTSuV) Prevalence in Wild Fauna of Northern Italy
Torque teno sus virus (TTSuV) is a non-enveloped circular ssDNA virus which frequently infects swine and has been associated with hepatic, respiratory, and autoimmune disorders. TTSuV’s pathogenic role is still uncertain, and clear data in the literature on virus reservoirs are lacking. The aims of this study were to investigate the presence of potentially zoonotic TTSuV in wild animals in Northern Italy and to evaluate their role as reservoirs. Liver samples were collected between 2016 and 2020 during four hunting seasons from wild boars (Sus scrofa), red deer (Cervus elaphus), roe deer (Capreolus capreolus), and chamois (Rupicapra rupicapra). Samples originated from areas in Northern Italy characterized by different traits, i.e., mountains and flatland with, respectively low and high farm density and anthropization. Viral identification was carried out by end-point PCR with specific primers for TTSuV1a and TTSuVk2a species. TTSuV prevalence in wild boars was higher in the mountains than in the flatland (prevalence of 6.2% and 2.3%, respectively). In wild ruminants only TTSuVk2a was detected (with a prevalence of 9.4%). Our findings shed light on the occurrence and distribution of TTSuV in some wild animal species, investigating their possible role as reservoirs
Nucleation and Growth of the Superconducting Phase in the Presence of a Current
We study the localized stationary solutions of the one-dimensional
time-dependent Ginzburg-Landau equations in the presence of a current. These
threshold perturbations separate undercritical perturbations which return to
the normal phase from overcritical perturbations which lead to the
superconducting phase. Careful numerical work in the small-current limit shows
that the amplitude of these solutions is exponentially small in the current; we
provide an approximate analysis which captures this behavior. As the current is
increased toward the stall current J*, the width of these solutions diverges
resulting in widely separated normal-superconducting interfaces. We map out
numerically the dependence of J* on u (a parameter characterizing the material)
and use asymptotic analysis to derive the behaviors for large u (J* ~ u^-1/4)
and small u (J -> J_c, the critical deparing current), which agree with the
numerical work in these regimes. For currents other than J* the interface
moves, and in this case we study the interface velocity as a function of u and
J. We find that the velocities are bounded both as J -> 0 and as J -> J_c,
contrary to previous claims.Comment: 13 pages, 10 figures, Revte
Possible human-to-dog transmission of SARS-CoV-2, Italy, 2020
We detected severe acute respiratory syndrome coronavirus 2 in an otherwise healthy poodle living with 4 family members who had coronavirus disease. We observed antibodies in serum samples taken from the dog, indicating seroconversion. Full-length genome sequencing showed that the canine and human viruses were identical, suggesting human-to-animal transmission
Relation between polymer and Fock excitations
To bridge the gap between background independent, non-perturbative quantum
gravity and low energy physics described by perturbative field theory in
Minkowski space-time, Minkowskian Fock states are located, analyzed and used in
the background independent framework. This approach to the analysis of
semi-classical issues is motivated by recent results of Varadarajan. As in that
work, we use the simpler U(1) example to illustrate our constructions but, in
contrast to that work, formulate the theory in such a way that it can be
extended to full general relativity.Comment: Clarifying remarks and three references added. To appear in CQ
The Phoenix Project: Master Constraint Programme for Loop Quantum Gravity
The Hamiltonian constraint remains the major unsolved problem in Loop Quantum
Gravity (LQG). Seven years ago a mathematically consistent candidate
Hamiltonian constraint has been proposed but there are still several unsettled
questions which concern the algebra of commutators among smeared Hamiltonian
constraints which must be faced in order to make progress. In this paper we
propose a solution to this set of problems based on the so-called {\bf Master
Constraint} which combines the smeared Hamiltonian constraints for all smearing
functions into a single constraint. If certain mathematical conditions, which
still have to be proved, hold, then not only the problems with the commutator
algebra could disappear, also chances are good that one can control the
solution space and the (quantum) Dirac observables of LQG. Even a decision on
whether the theory has the correct classical limit and a connection with the
path integral (or spin foam) formulation could be in reach. While these are
exciting possibilities, we should warn the reader from the outset that, since
the proposal is, to the best of our knowledge, completely new and has been
barely tested in solvable models, there might be caveats which we are presently
unaware of and render the whole {\bf Master Constraint Programme} obsolete.
Thus, this paper should really be viewed as a proposal only, rather than a
presentation of hard results, which however we intend to supply in future
submissions.Comment: LATEX, uses AMSTE
Crystallization of the ordered vortex phase in high temperature superconductors
The Landau-Khalatnikov time-dependent equation is applied to describe the
crystallization process of the ordered vortex lattice in high temperature
superconductors after a sudden application of a magnetic field. Dynamic
coexistence of a stable ordered phase and an unstable disordered phase, with a
sharp interface between them, is demonstrated. The transformation to the
equilibrium ordered state proceeds by movement of this interface from the
sample center toward its edge. The theoretical analysis dictates specific
conditions for the creation of a propagating interface, and provides the time
scale for this process.Comment: 8 pages and 3 figures; to be published in Phys. Rev. B (Rapid
Communications section
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