68 research outputs found
Influencia en la cafeína sobre la motilidad, supervivencia y acrosomia espermática del semen descongelado de morueco
[ES] Influencia en la cafeína sobre la motilidad, supervivencia y acrosomia espermática del semen descongelado de moruec
Lepton Masses and Mixing in a Left-Right Symmetric Model with a TeV-scale Gravity
We construct a left-right symmetric (LRS) model in five dimensions which
accounts naturally for the lepton flavor parameters. The fifth dimension is
described by an orbifold, S_1/Z_2 times Z'_2, with a typical size of order
TeV^{-1}. The fundamental scale is of order 25 TeV which implies that the gauge
hierarchy problem is ameliorated. In addition the LRS breaking scale is of
order few TeV which implies that interactions beyond those of the standard
model are accessible to near future experiments. Leptons of different
representations are localized around different orbifold fixed points. This
explains, through the Arkani-Hamed-Schmaltz mechanism, the smallness of the tau
mass compared to the electroweak breaking scale. An additional U(1) horizontal
symmetry, broken by small parameters, yields the hierarchy in the charged
lepton masses, strong suppression of the light neutrino masses and accounts for
the mixing parameters. The model yields several unique predictions. In
particular, the branching ratio for the lepton flavor violating process mu^-
--> e^+ e^- e^- is comparable with its present experimental sensitivity.Comment: 21 pages, 1 figure, references added, discussion on the
predictiveness of the model in the generic non-universal case added, to
appear in PR
Neutrino masses: From fantasy to facts
Theory suggests the existence of neutrino masses, but little more. Facts are
coming close to reveal our fantasy: solar and atmospheric neutrino data
strongly indicate the need for neutrino conversions, while LSND provides an
intriguing hint. The simplest ways to reconcile these data in terms of neutrino
oscillations invoke a light sterile neutrino in addition to the three active
ones. Out of the four neutrinos, two are maximally-mixed and lie at the LSND
scale, while the others are at the solar mass scale. These schemes can be
distinguished at neutral-current-sensitive solar & atmospheric neutrino
experiments. I discuss the simplest theoretical scenarios, where the lightness
of the sterile neutrino, the nearly maximal atmospheric neutrino mixing, and
the generation of & all follow
naturally from the assumed lepton-number symmetry and its breaking. Although
the most likely interpretation of the present data is in terms of
neutrino-mass-induced oscillations, one still has room for alternative
explanations, such as flavour changing neutrino interactions, with no need for
neutrino mass or mixing. Such flavour violating transitions arise in theories
with strictly massless neutrinos, and may lead to other sizeable flavour
non-conservation effects, such as , conversion in
nuclei, unaccompanied by neutrino-less double beta decay.Comment: 33 pages, latex, 16 figures. Invited Talk at Ioannina Conference,
Symmetries in Intermediate High Energy Physics and its Applications, Oct.
1998, to be published by Springer Tracts in Modern Physics. Festschrift in
Honour of John Vergados' 60th Birthda
Severe manifestations of SARS-CoV-2 in children and adolescents: from COVID-19 pneumonia to multisystem inflammatory syndrome: a multicentre study in pediatric intensive care units in Spain
Background
Multisystem inflammatory syndrome temporally associated with COVID-19 (MIS-C) has been described as a novel and often severe presentation of SARS-CoV-2 infection in children. We aimed to describe the characteristics of children admitted to Pediatric Intensive Care Units (PICUs) presenting with MIS-C in comparison with those admitted with SARS-CoV-2 infection with other features such as COVID-19 pneumonia.
Methods
A multicentric prospective national registry including 47 PICUs was carried out. Data from children admitted with confirmed SARS-CoV-2 infection or fulfilling MIS-C criteria (with or without SARS-CoV-2 PCR confirmation) were collected. Clinical, laboratory and therapeutic features between MIS-C and non-MIS-C patients were compared.
Results
Seventy-four children were recruited. Sixty-one percent met MIS-C definition. MIS-C patients were older than non-MIS-C patients (p = 0.002): 9.4 years (IQR 5.5–11.8) vs 3.4 years (IQR 0.4–9.4). A higher proportion of them had no previous medical history of interest (88.2% vs 51.7%, p = 0.005). Non-MIS-C patients presented more frequently with respiratory distress (60.7% vs 13.3%, p < 0.001). MIS-C patients showed higher prevalence of fever (95.6% vs 64.3%, p < 0.001), diarrhea (66.7% vs 11.5%, p < 0.001), vomits (71.1% vs 23.1%, p = 0.001), fatigue (65.9% vs 36%, p = 0.016), shock (84.4% vs 13.8%, p < 0.001) and cardiac dysfunction (53.3% vs 10.3%, p = 0.001). MIS-C group had a lower lymphocyte count (p < 0.001) and LDH (p = 0.001) but higher neutrophil count (p = 0.045), neutrophil/lymphocyte ratio (p < 0.001), C-reactive protein (p < 0.001) and procalcitonin (p < 0.001). Patients in the MIS-C group were less likely to receive invasive ventilation (13.3% vs 41.4%, p = 0.005) but were more often treated with vasoactive drugs (66.7% vs 24.1%, p < 0.001), corticosteroids (80% vs 44.8%, p = 0.003) and immunoglobulins (51.1% vs 6.9%, p < 0.001). Most patients were discharged from PICU by the end of data collection with a median length of stay of 5 days (IQR 2.5–8 days) in the MIS-C group. Three patients died, none of them belonged to the MIS-C group.
Conclusions
MIS-C seems to be the most frequent presentation among critically ill children with SARS-CoV-2 infection. MIS-C patients are older and usually healthy. They show a higher prevalence of gastrointestinal symptoms and shock and are more likely to receive vasoactive drugs and immunomodulators and less likely to need mechanical ventilation than non-MIS-C patients
Efeito residual da adubação da batata sobre a produção do milho-verde em cultivo sucessivo
Astronomical Distance Determination in the Space Age: Secondary Distance Indicators
The formal division of the distance indicators into primary and secondary leads to difficulties in description of methods which can actually be used in two ways: with, and without the support of the other methods for scaling. Thus instead of concentrating on the scaling requirement we concentrate on all methods of distance determination to extragalactic sources which are designated, at least formally, to use for individual sources. Among those, the Supernovae Ia is clearly the leader due to its enormous success in determination of the expansion rate of the Universe. However, new methods are rapidly developing, and there is also a progress in more traditional methods. We give a general overview of the methods but we mostly concentrate on the most recent developments in each field, and future expectations. © 2018, The Author(s)
Efeito da adubação com boro e esterco bovino sobre a produtividade da figueira e as propriedades químicas do solo
Efeito da revegetação e da adubação de área degradada na fertilidade do solo e nas características da palhada
Autoantibodies against type I IFNs in patients with life-threatening COVID-19
Interindividual clinical variability in the course of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is vast. We report that at least 101 of 987 patients with life-threatening coronavirus disease 2019 (COVID-19) pneumonia had neutralizing immunoglobulin G (IgG) autoantibodies (auto-Abs) against interferon-w (IFN-w) (13 patients), against the 13 types of IFN-a (36), or against both (52) at the onset of critical disease; a few also had auto-Abs against the other three type I IFNs. The auto-Abs neutralize the ability of the corresponding type I IFNs to block SARS-CoV-2 infection in vitro. These auto-Abs were not found in 663 individuals with asymptomatic or mild SARS-CoV-2 infection and were present in only 4 of 1227 healthy individuals. Patients with auto-Abs were aged 25 to 87 years and 95 of the 101 were men. A B cell autoimmune phenocopy of inborn errors of type I IFN immunity accounts for life-threatening COVID-19 pneumonia in at least 2.6% of women and 12.5% of men
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