3,101 research outputs found
Majorana vs Pseudo-Dirac Neutrinos at the ILC
Neutrino masses could originate in seesaw models testable at colliders, with
light mediators and an approximate lepton number symmetry. The minimal model of
this type contains two quasi-degenerate Majorana fermions forming a
pseudo-Dirac pair. An important question is to what extent future colliders
will have sensitivity to the splitting between the Majorana components, since
this quantity signals the breaking of lepton number and is connected to the
light neutrino masses. We consider the production of these neutral heavy
leptons at the ILC, where their displaced decays provide a golden signal: a
forward-backward charge asymmetry, which depends crucially on the mass
splitting between the two Majorana components. We show that this observable can
constrain the mass splitting to values much lower than current bounds from
neutrinoless double beta decay and natural loop corrections.Comment: 16 pages, 5 figures; v2: Minor changes, version accepted for
publication in EPJ
JCLAL: A Java framework for active learning
Active Learning has become an important area of research owing to the increasing number of real-world problems which contain labelled and unlabelled examples at the same time. JCLAL is a Java Class Library for Active Learning which has an architecture that follows strong principles of object-oriented design. It is easy to use, and it allows the developers to adapt, modify and extend the framework according to their needs. The library offers a variety of active learning methods that have been proposed in the literature. The software is available under the GPL license
N-(2-Furylcarbonyl)piperidine-1-carbothioamide
The title compound, C11H14N2O2S, was synthesized from furoyl isothiocyanate and piperidine in dry acetone. The thiourea group is in the thioamide form. The thiourea group makes a dihedral angle of 53.9 (1)° with the furan carbonyl group. In the crystal structure, molecules are linked by intermolecular N—H⋯O hydrogen bonds, forming one-dimensional chains along the c axis. An intramolecular N—H⋯O hydrogen bond is also present
Diagramas de predominancia, de frost y de pourbaix: tres contextos para desarrollar competencias en procesos de óxido-reducción
En el aprendizaje de la Química es necesario desarrollar algunas competencias (interpretación, argumentación, proposición) relacionadas con el conocimiento de la reactividad de varias especies inorgánicas en los procesos de oxidaciónreducción y la habilidad para predecir y manejar adecuadamente los productos de reacción. Las tendencias termodinámicas (estabilidad o reactividad) de diferentes especies de elementos en tales procesos pueden entenderse mediante la construcción e interpretación de diagramas termodinámicos (diagramas de predominancia, de Frost y de Pourbaix). El presente trabajo muestra una revisión actualizada y una discusión integrada de estos tres tipos de diagramas, considerándolos como tres contextos pedagógicos importantes en Química
Genotoxic and Cytotoxic Studies of Beta-Sitosterol and Pteropodine in Mouse
Beta-sitosterol (BS) and pteropodine (PT) are constituents of various plants with pharmacological activities potentially useful to man. The chemicals themselves possess biomedical properties related to the modulation of the immune and the nervous systems, as well as to the inflammatory process. Therefore, safety evaluation of the compounds is necessary in regard to their probable beneficial use in human health. The present study evaluates their genotoxic and cytotoxic potential by determining the capacity of the compounds to induce sister chromatid exchanges (SCE), or to alter cellular proliferation kinetics (CPK) and the mitotic index (MI) in mouse bone marrow cells. Besides, it also determines their capacity to increase the rate of micronucleated polychromatic erythrocytes (MNPE) in peripheral mouse blood, and the relationship polychromatic erythrocytes/normochromatic erythrocytes (PE/NE) as an index of cytotoxicity. For the first assay, four doses of each compound were tested: 200, 400, 600, and 1000 mg/kg in case of BS, and 100, 200, 300, and 600 mg/kg for PT. The results in regard to both agents showed no SCE increase induced by any of the tested doses, as well as no alteration in the CPK, or in the MI. With respect to the second assay, the results obtained with the two agents were also negative for both the MNPE and the PE/NE index along the daily evaluation made for four days. In the present study, the highest tested dose corresponded to 80% of the LD(50) obtained for BS and to 78% in the case of PT. The results obtained establish that the studied agents have neither genotoxic nor cytotoxic effect on the model used, and therefore they encourage studies on their pharmacological properties
1-Furoyl-3-[3-(trifluoromethyl)phenyl]thiourea
The title compound, C13H9F3N2O2S, crystallizes with two independent molecules in the asymmetric unit. The central thiourea core is roughly coplanar with the furan and benzene rings, showing O—C—N—C(S) torsion angles of 2.3 (4) and −11.4 (2)° and (S)C—N—C—C torsion angles of −2.4 (4) and −28.8 (4)°, respectively, in the two independent molecules. The trans–cis geometry of the thiourea fragment is stabilized by an intramolecular N—H⋯O hydrogen bond between the H atom of the cis thioamide and the carbonyl O atom. In the crystal structure, intermolecular N—H⋯S hydrogen bonds form centrosymmetric dimers extending along the b axis
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