44 research outputs found
Solar neutrino detection
More than 40 years ago, neutrinos where conceived as a way to test the
validity of the solar models which tell us that stars are powered by nuclear
fusion reactions. The first measurement of the neutrino flux, in 1968 in the
Homestake mine in South Dakota, detected only one third of the expected value,
originating what has been known as the Solar Neutrino Problem. Different
experiments were built in order to understand the origin of this discrepancy.
Now we know that neutrinos undergo oscillation phenomenon changing their nature
traveling from the core of the Sun to our detectors. In the work the 40 year
long saga of the neutrino detection is presented; from the first proposals to
test the solar models to last real time measurements of the low energy part of
the neutrino spectrum.Comment: 8 pages, 5 figures. III School on Cosmic Rays and Astrophysics August
25 to September 5, 2008 Arequipa (Peru) AIP conference proceedin
IceCube3--a new window on the Universe
This paper gives an overview of the scientific goals of IceCube with an
emphasis on the importance of atmospheric neutrinos. Status and schedule for
completing the detector are presented.Comment: 13 pages, 6 figures, to appear in A.I.P. Conf. Proceedings, 3rd Latin
American School on Cosmic Rays, Arequipa, Peru, September, 200
A model for the electromagnetic spectrum of the inner jets of Cen A
Centaurus A, the closest active galaxy, has been detected from radio to
high-energy gamma-rays. The synchrotron radiation by extremely high energy
protons may be a suitable mechanism to explain the MeV to GeV emission detected
by the instruments of the Compton Gamma-Ray Observatory, as coming from the
inner jets. This scenario requires a relatively large magnetic field of about
10^4 G that could be present only close to the central black hole. We
investigate the spectral energy distribution (SED) resulting from a one-zone
compact acceleration region, where both leptonic and hadronic relativistic
populations arise.
We present here results of such a model, where we have considered synchrotron
radiation by primary electrons and protons, inverse Compton interactions, and
gamma-ray emission originated by the inelastic hadronic interactions between
relativistic protons and cold nuclei within the jets themselves. Photo-meson
production by relativistic hadrons were also taken into account, as well as the
effects of secondary particles injected by all interactions. The internal and
external absorption of gamma rays is shown to be of great relevance to shape
the observable SED, which was also recently constrained by the results of HESS.Comment: 13 pages (ref. style), submitted to MNRAS on December 04, 2008.
Waiting for revie
One-year breakthrough SARS-CoV-2 infection and correlates of protection in fully vaccinated hematological patients
The long-term clinical efficacy of SARS-CoV-2 vaccines according to antibody response in immunosuppressed patients such as hematological patients has been little explored. A prospective multicenter registry-based cohort study conducted from December 2020 to July 2022 by the Spanish Transplant and Cell Therapy group, was used to analyze the relationship of antibody response over time after full vaccination (at 3-6 weeks, 3, 6 and 12 months) (2 doses) and of booster doses with breakthrough SARS-CoV-2 infection in 1551 patients with hematological disorders. At a median follow-up of 388 days after complete immunization, 266 out of 1551 (17%) developed breakthrough SARS-CoV-2 infection at median of 86 days (range 7-391) after full vaccination. The cumulative incidence was 18% [95% confidence interval (C.I.), 16-20%]. Multivariate analysis identified higher incidence in chronic lymphocytic leukemia patients (29%) and with the use of corticosteroids (24.5%), whereas female sex (15.5%) and more than 1 year after last therapy (14%) were associated with a lower incidence (p < 0.05 for all comparisons). Median antibody titers at different time points were significantly lower in breakthrough cases than in non-cases. A serological titer cut-off of 250 BAU/mL was predictive of breakthrough infection and its severity. SARS-CoV-2 infection-related mortality was encouragingly low (1.9%) in our series. Our study describes the incidence of and risk factors for COVID-19 breakthrough infections during the initial vaccination and booster doses in the 2021 to mid-2022 period. The level of antibody titers at any time after 2-dose vaccination is strongly linked with protection against both breakthrough infection and severe disease, even with the Omicron SARS-CoV-2 variant
SARS-CoV-2-reactive antibody detection after SARS-CoV-2 vaccination in hematopoietic stem cell transplant recipients: Prospective survey from the Spanish Hematopoietic Stem Cell Transplantation and Cell Therapy Group
This is a multicenter prospective observational study that included a large cohort (n = 397) of allogeneic (allo-HSCT; (n = 311) and autologous (ASCT) hematopoietic stem cell transplant (n = 86) recipients who were monitored for antibody detection within 3–6 weeks after complete severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination from February 1, 2021, to July 20, 2021. Most patients (n = 387, 97.4%) received mRNA-based vaccines. Most of the recipients (93%) were vaccinated more than 1 year after transplant. Detectable SARS-CoV-2-reactive antibodies were observed in 242 (78%) of allo-HSCT and in 73 (85%) of ASCT recipients. Multivariate analysis in allo-HSCT recipients identified lymphopenia < 1 × 109/ml (odds ratio [OR] 0.33, 95% confidence interval [95% CI] 0.16–0.69, p = .003), active graft versus host disease (GvHD; OR 0.51, 95% CI 0.27–0.98, p = .04) and vaccination within the first year of transplant (OR 0.3, 95% CI 0.15–0.9, p = .04) associated with lower antibody detection whereas. In ASCT, non-Hodgkin's lymphoma (NHL; OR 0.09, 95% CI 0.02–0.44, p = .003) and active corticosteroid therapy (OR 0.2, 95% CI 0.02–0.87, p = .03) were associated with lower detection rate. We report an encouraging rate of SARS-CoV-2-reactive antibodies detection in these severe immunocompromised patients. Lymphopenia, GvHD, the timing of vaccine, and NHL and corticosteroids therapy should be considered in allo-HSCT and ASCT, respectively, to identify candidates for SARS-CoV-2 antibodies monitoring.Peer reviewe
The Research on the Institution Innovation of the Land-losing Peasants’ Employment Settlement
当前,随着城市化进程的快速推进,失地农民就业问题己成为影响经济发展、社会稳定、和谐社会构建的一个突出问题,成为摆在各级党委政府面前必须尽快解决的一个重大而现实的问题。本文采用文献法和个案实证法,在正确把握失地农民就业问题理论基础、客观分析全国失地农民就业安置现状、剖析借鉴厦门市“金包银”工程促进失地农民实现再就业经验和教训的基础上,积极探索促进失地农民再就业的有效途径,提出一些具有指导意义和可操作性的政策建议。全文共分为四部分:第一部分,导论。重点介绍了问题的研究背景、方法和意义,阐述了基础理论和相关概念以及国内外的研究文献,夯实了理论基础。第二部分,失地农民就业安置的制度变迁与实践分析。重点...Currently, with the fast enforcement of urbanization, the issue of land-losing peasants has become an outstanding problem which effects the economic development, social stability and construction of harmonious society, and has become an important and realistic problem which now confronted by the CPC committees and the government of all levels and which should be solved as quickly as possible. This...学位:管理学硕士院系专业:公共事务学院公共管理系_行政管理学号:1392006115072