1,221 research outputs found
X(3872) and its Partners in the Heavy Quark Limit of QCD
In this letter, we propose interpolating currents for the X(3872) resonance,
and show that, in the Heavy Quark limit of QCD, the X(3872) state should have
degenerate partners, independent of its internal structure. Magnitudes of
possible I=0 and I=1 components of the X(3872) are also discussed.Comment: 12 page
Intervención sobre la suma mediante el uso combinado de regletas y TIC’s
Se trata de una investigación empÃrico-cuantitativa que pretende comprobar que las claves de Driver y Bell (1986) sobre aprendizaje manipulativo y significativo son efectivas para el aprendizaje de la suma en alumnos de 4º de Primaria que presentan dificultades de aprendizaje (Radatz, 1979, 1980). Esta intervención se realizó en el último semestre del curso 2014/2015 en el colegio de la Asunción de Ponferrada. El grupo-clase está formado por 25 alumnos (14 niñas y 11 niños) de 4º de Primaria en donde se aprecia en general déficit de atención, acentuado en tres alumnos, uno de ellos diagnosticado
Human immunodeficiency virus type 1 recombinant B/G subtypes circulating in Coimbra, Portugal.
An increasing prevalence of HIV-1 non-B variants is being noticed in several European regions, particularly in countries such as Portugal, which have closer contacts with African endemic areas, where multiple HIV subtypes cocirculate. HIV-1 subtyping by phylogenetic analyses of reverse transcriptase, protease and env (C2-V3) genomic regions was carried out in plasma collected from 18 HIV-1-infected subjects living in Coimbra, Portugal, and suspected to be infected with non-B variants. Three (16.7%) subjects carried recombinant B/G viruses (BV3/BRT/Gpro; GV3/URT/Bpro; AV3/GRT/Bpro), whereas all the remaining individuals were infected with HIV-1 subtype B. This is the first report of recombinant B/G subtypes in Portugal
Extinction time in growth models subject to binomial catastrophes
Populations are often subject to catastrophes that cause mass removal of
individuals. Many stochastic growth models have been considered to explain such
dynamics. Among the results reported, it has been considered whether dispersion
strategies, at times of catastrophes, increase the survival probability of the
population. In this paper, we contrast dispersion strategies comparing mean
extinction times of the population when extinction occurs almost surely. In
particular, we consider populations subject to binomial catastrophes, that is,
the population size is reduced according to a binomial law when a catastrophe
occurs. Our results show which is the best strategy (dispersion or
non-dispersion) depending on model parameter values.Comment: 15 pages, 2 figures. arXiv admin note: substantial text overlap with
arXiv:2109.1099
Clinical manifestations of pandemic (H1N1) 2009 in the ambulatory setting
INTRODUCTION: In June 2009, the World Health Organization declared an influenza pandemic associated with the pandemic (H1N1) 2009 strain. It was summer in the northern hemisphere, and therefore travelling and vacation time, which also provided an increased opportunity for the dissemination of respiratory diseases.
METHODOLOGY: We reviewed the paper case report forms from all the patients with influenza-like illnesses with nasopharyngeal samples submitted for laboratory diagnosis of pandemic (H1N1) 2009 infection during the first wave of pandemic influenza that occurred between June and August 2009, in the central region of Portugal.
RESULTS: From all the patients with influenza-like illnesses, one third was found positive for pandemic (H1N1) 2009. Individuals under the age of 29 (75%) were the most affected. Most of the patients (91%) presented with fever. A group of symptoms were positively correlated with the probability of pandemic (H1N1) 2009 infection: cough, epistaxis, lack of dyspnea or vomiting, fever, headache and myalgia.
CONCLUSIONS: During the first wave of the pandemic influenza, young individuals were the most affected, and in the ambulatory setting, presentation was of a mild febrile illness without complications
First report of acute autochthonous hepatitis E in Portugal
Hepatitis E infection is usually a self-limiting disease. In industrialized countries, sporadic cases of acute hepatitis E virus (HEV) infections have been described; their number seems to be increasing in European countries. We report the first human case of autochthonous acute hepatitis E confirmed in Portugal. Patients with acute non-A-C hepatitis should be tested for HEV in Portugal and hepatitis E infection should be considered in the differential diagnosis of unexplained hepatitis cases
Plasmodium falciparum malaria, bilateral sixth cranial nerve palsy and delayed cerebellar ataxia
We describe the case of a 14-year-old Caucasian male, a resident in the Democratic Republic of the Congo, who was observed in Portugal with severe Plasmodium falciparum malaria with high-level parasitemia and severe thrombocytopenia. The course was complicated by bilateral sixth cranial nerve palsy during acute malaria, followed by the appearance of delayed cerebellar ataxia during the recovery phase. This occurred after successful treatment with quinine plus doxycycline over seven days. Different levels of thrombocytopenia and C-reactive protein were observed during both neurologic events in the presence of HRP-2 positive tests for Plasmodium falciparum antigen. The patient recovered completely after three months
Phase-Sensitive Vibrational Sum and Difference Frequency-Generation Spectroscopy Enabling Nanometer-Depth Profiling at Interfaces
The unique physical and chemical properties of interfaces are governed by a finite depth that describes the transition from the topmost atomic layer to the properties of the bulk material. Thus, understanding the physical nature of interfaces requires detailed insight into the different structures, chemical compositions, and physical processes that form this interfacial region. Such insight has traditionally been difficult to obtain from experiments, as it requires a combination of structural and chemical sensitivity with spatial depth resolution on the nanometer scale. In this contribution, we present a vibrational spectroscopic approach that can overcome these limitations. By combining phase-sensitive sum and difference frequency-generation (SFG and DFG, respectively) spectroscopy and by selectively determining different nonlinear interaction pathways, we can extract precise depth information and correlate these to specific vibrationally resonant modes of interfacial species. We detail the mathematical framework behind this approach and demonstrate the performance of this technique in two sets of experiments on selected model samples. An analysis of the results shows an almost perfect match between experiment and theory, confirming the practicability of the proposed concept under realistic experimental conditions. Furthermore, in measurements with self-assembled monolayers of different chain lengths, we analyze the spatial accuracy of the technique and find that the precision can even reach the sub-nanometer regime. We also discuss the implications and the information content of such depth-sensitive measurements and show that the concept is very general and goes beyond the analysis of the depth profiles. The presented SFG/DFG technique offers new perspectives for spectroscopic investigations of interfaces in various material systems by providing access to fundamental observables that have so far been inaccessible by experiments. Here, we set the theoretical and experimental basis for such future investigations
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