122 research outputs found

    Phenomenology from relativistic Levy-Schroedinger equations: Application to neutrinos

    Get PDF
    In continuation of a previous paper a close connection between Feynman propagators and a particular L\'evy stochastic process is established. The approach can be easily applied to the Standard Model SU_C(3)xSU_L(2)xU(1) providing qualitative interesting results. Quantitative results, compatible with experimental data, are obtained in the case of neutrinos

    Mass spectrum from stochastic Levy-Schroedinger relativistic equations: possible qualitative predictions in QCD

    Get PDF
    Starting from the relation between the kinetic energy of a free Levy-Schroedinger particle and the logarithmic characteristic of the underlying stochastic process, we show that it is possible to get a precise relation between renormalizable field theories and a specific Levy process. This subsequently leads to a particular cut-off in the perturbative diagrams and can produce a phenomenological mass spectrum that allows an interpretation of quarks and leptons distributed in the three families of the standard model.Comment: 8 pages, no figures. arXiv admin note: substantial text overlap with arXiv:1008.425

    European College of Equine Internal Medicine consensus statement on equine flaviviridae infections in Europe

    Get PDF
    Horses and other equids can be infected with several viruses of the family Flaviviridae, belonging to the genus Flavivirus and Hepacivirus. This consensus statement focuses on viruses with known occurrence in Europe, with the objective to summarize the current literature and formulate clinically relevant evidence-based recommendations regarding clinical disease, diagnosis, treatment, and prevention. The viruses circulating in Europe include West Nile virus, tick-borne encephalitis virus, Usutu virus, Louping ill virus and the equine hepacivirus. West Nile virus and Usutu virus are mosquito-borne, while tick-borne encephalitis virus and Louping ill virus are tick-borne. The natural route of transmission for equine hepacivirus remains speculative. West Nile virus and tick-borne encephalitis virus can induce encephalitis in infected horses. In the British Isle, rare equine cases of encephalitis associated with Louping ill virus are reported. In contrast, equine hepacivirus infections are associated with mild acute hepatitis and possibly chronic hepatitis. Diagnosis of flavivirus infections is made primarily by serology, although cross-reactivity occurs. Virus neutralization testing is considered the gold standard to differentiate between flavivirus infections in horses. Hepacivirus infection is detected by serum or liver RT-PCR. No direct antiviral treatment against flavi- or hepacivirus infections in horses is currently available and thus, treatment is supportive. Three vaccines against West Nile virus are licensed in the European Union. Geographic expansion of flaviviruses pathogenic for equids should always be considered a realistic threat, and it would be beneficial if their detection was included in surveillance programs

    Serological and Molecular Investigation of SARS-CoV-2 in Horses and Cattle in Switzerland from 2020 to 2022

    Get PDF
    Horses and cattle have shown low susceptibility to SARS-CoV-2, and there is no evidence of experimental intraspecies transmission. Nonetheless, seropositive horses in the US and seropositive cattle in Germany and Italy have been reported. The current study investigated the prevalence of antibodies against SARS-CoV-2 in horses and cattle in Switzerland. In total, 1940 serum and plasma samples from 1110 horses and 830 cattle were screened with a species-specific ELISA based on the SARS-CoV-2 receptor-binding domain (RBD) and, in the case of suspect positive results, a surrogate virus neutralization test (sVNT) was used to demonstrate the neutralizing activity of the antibodies. Further confirmation of suspect positive samples was performed using either a pseudotype-based virus neutralization assay (PVNA; horses) or an indirect immunofluorescence test (IFA; cattle). The animals were sampled between February 2020 and December 2022. Additionally, in total, 486 bronchoalveolar lavage (BAL), oropharyngeal, nasal and rectal swab samples from horses and cattle were analyzed for the presence of SARS-CoV-2 RNA via reverse transcriptase quantitative polymerase chain reaction (RT-qPCR). Six horses (0.5%; 95% CI: 0.2–1.2%) were suspect positive via RBD-ELISA, and neutralizing antibodies were detected in two of them via confirmatory sVNT and PVNA tests. In the PVNA, the highest titers were measured against the Alpha and Delta SARS-CoV-2 variants. Fifteen cattle (1.8%; 95% CI: 1.0–3.0%) were suspect positive in RBD-ELISA; 3 of them had SARS-CoV-2-specific neutralizing antibodies in sVNT and 4 of the 15 were confirmed to be positive via IFA. All tested samples were RT-qPCR-negative. The results support the hypotheses that the prevalence of SARS-CoV-2 infections in horses and cattle in Switzerland was low up to the end of 2022

    Levy processes and Schroedinger equation

    Full text link
    We analyze the extension of the well known relation between Brownian motion and Schroedinger equation to the family of Levy processes. We consider a Levy-Schroedinger equation where the usual kinetic energy operator - the Laplacian - is generalized by means of a selfadjoint, pseudodifferential operator whose symbol is the logarithmic characteristic of an infinitely divisible law. The Levy-Khintchin formula shows then how to write down this operator in an integro--differential form. When the underlying Levy process is stable we recover as a particular case the fractional Schroedinger equation. A few examples are finally given and we find that there are physically relevant models (such as a form of the relativistic Schroedinger equation) that are in the domain of the non-stable, Levy-Schroedinger equations.Comment: 10 pages; changed the TeX documentclass; added references [21] and [22] and comments about them; changed definitions (11) and (12); added acknowledgments; small changes scattered in the tex

    Investigation of Three Newly Identified Equine Parvoviruses in Blood and Nasal Fluid Samples of Clinically Healthy Horses and Horses with Acute Onset of Respiratory Disease

    No full text
    Three newly identified equine parvoviruses (equine parvovirus hepatitis (EqPV-H), equine parvovirus CSF (EqPV-CSF) and equine copivirus (Eqcopivirus)) have recently been discovered in horses with respiratory signs. However, the clinical impact of these three equine parvoviruses has yet to be determined. Nasal fluid samples and blood from 667 equids with acute onset of fever and respiratory signs submitted to a diagnostic laboratory were analyzed for the presence of common equine respiratory pathogens (equine influenza virus, equine herpesvirus-1/-4, equine rhinitis A and B virus, S. equi subspecies equi) as well as EqPV-H, EqPV-CSF and Eqcopivirus by qPCR. An additional 87 clinically healthy horses served as controls. One hundred and seventeen sick horses tested qPCR-positive for at least one of the three parvoviruses. Co-infections with common respiratory pathogens and parvoviruses were seen in 39 sick equids. All 87 clinically healthy horses tested qPCR-negative for all tested common respiratory pathogens and 10 healthy horses tested qPCR-positive for one of the equine parvoviruses. When the frequency of detection for EqPV-H, EqPV-CSF and Eqcopivirus of equids with respiratory signs was compared to that of clinically healthy horses, the difference was not statistically significant (p > 0.05), suggesting that the three recently identified equine parvoviruses do not contribute to the clinical picture of equids with respiratory disease
    • …
    corecore