2,572 research outputs found
CP violating phase from charged-lepton mixing
A model independent analysis of the leptonic Dirac CP-violating phase
({\delta}) is presented. The analysis uses the experimentally determined values
of the mixing angles in the lepton mixing matrix in order to explore the
allowed values for {\delta} and possible general forms for the charged lepton
mixing matrix. This is done under two general assumptions: 1) that the mixing
matrix in the neutrino sector is the so-called tribimaximal matrix and hence
the non zero value for {\theta}13 arises due to the mixing matrix in the
charged lepton sector and 2) the charged lepton mixing matrix is parametrized
in terms of three angles and one phase. It is found that any value of {\delta}
is still consistent with the data and that, considering the assumptions above,
regardless of the value for {\delta}, the 1-3 mixing angle in the charged
lepton sector is small but non zero and the 2-3 mixing angle can take values in
only two possible small ranges around 0 and {\pi}/2 respectively.Comment: References adde
Caracterização química da cerâmica arqueológica do Baixo Rio Paraná
This paper analyzed the chemical composition of archaeological pottery produced by hunter-gatherers and horticulturist populations of the late Holocene of the lower Paraná basin. An energy dispersive X-ray fluorescence spectrometer was used to analyze the chemical composition of the sherds. The results obtained indicated that the analyzed samples, within certain parameters, showed some variability. The differences were even more significant when comparing the chemical composition of the pottery of the huntergatherer groups and that of the horticulturists. The main components identified in the archaeological pottery were grouped primarily with the location of production, that is, they were the result of local manufacturing. Within the trace-elements, the greatest variations in composition were observed in the strontium, which was assumed to vary in concentration levels throughout the region.Este artigo analisou a composição mineralógica da cerâmica arqueológica produzida por populações de caçadores-coletores e horticultores do Holoceno tardio na parte baixa da bacia do Paraná. Para analisar a composição química dos fragmentos foi utilizado um espectrômetro de fluorescência de raios X de energia dispersiva. Os resultados obtidos indicaram que as amostras analisadas, dentro de certos parâmetros, apresentaram alguma variabilidade. As diferenças foram ainda mais significativas quando se compararam a composição química da cerâmica dos grupos caçadores-coletores com a dos horticultores. Os componentes principais identificados nas cerâmicas arqueológicas foram agrupados de acordo com o local de produção, isto é, resultaram de confecção local. Quanto aos elementos-traço, a maior variação foi relacionada ao estrôncio, que foi assumido variar em níveis de concentração em toda a região.Fil: Loponte, Daniel Marcelo. Secretaría de Cultura de la Nación. Dirección Nacional de Cultura y Museos. Instituto Nacional de Antropología y Pensamiento Latinoamericano; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Morales J.. Universidad Nacional Autónoma de México; MéxicoFil: Gogichaishvili, Avtandil. Universidad Nacional Autónoma de México; MéxicoFil: Acosta, Alejandro Alberto. Secretaría de Cultura de la Nación. Dirección Nacional de Cultura y Museos. Instituto Nacional de Antropología y Pensamiento Latinoamericano; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
The archaeointensity of the earth's magnetic field retrieved from Pampean ceramics (South America)
Absolute intensity determinations using the Coe variant of the Thellier method have been carried out on some selected pottery fragments collected in the wetlands of the lower Paraná (Pampean region, Argentina) in order to construct the first archaeointensity master curve for South America. Associated radiometric ages range between 1640±70 and 730±70 bp. Twenty-one samples (five fragments) out of 46 studied (eight fragments) provided successful absolute intensity determinations. The fragment-mean archaeointensity values obtained in this study range from 21.9±2.3 to 42.6±5.4 μT, with corresponding virtual axial dipole moments (VADMs) ranging from 4.0±0.5 to 8.1±1.0 x 10 22Am 2. This corresponds to a mean VADM of (6.4±1.8)×10 22 Am 2. The synthetic record retrieved from southern Argentina and Brazil consists of 17 mean archaeointensities distributed between approximately ad 700 and ad 1700. The data set shows several distinct periods of fluctuations of quite large intensity. However, most data are concentrated into a relatively narrow time period from ad 950 to ad 1300. Three general features may be detected: the time intervals from about ad 950 to 1130 and 1350 to 1480 are characterized by quite monotonic increases of geomagnetic intensity, while some decrease is observed from ad 1150 to 1280. These variations may be speculatively correlated to climate changes over multi-decadal time scales. Important differences are observed between the data and the geomagnetic field predictions derived from recently reported global models, which reinforces the importance of regional reference curves for dating purposes.Fil: Goguitchaichvili, A.. Universidad Nacional Autónoma de México; MéxicoFil: Loponte, Daniel Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Secretaría de Cultura de la Nación. Dirección Nacional de Cultura y Museos. Instituto Nacional de Antropología y Pensamiento Latinoamericano; ArgentinaFil: Morales, J.. Universidad Nacional Autónoma de México; MéxicoFil: Acosta, Alejandro Alberto. Secretaría de Cultura de la Nación. Dirección Nacional de Cultura y Museos. Instituto Nacional de Antropología y Pensamiento Latinoamericano; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Non-diagonal charged lepton mass matrix and non-zero
Assuming that the neutrino mass matrix is diagonalized by the tribimaximal
mixing matrix, we explore the textures for the charged lepton mass matrix that
render an lepton mixing matrix consistent with data. In particular
we are interested in finding the textures with the maximum number of zeros. We
explore the cases of real matrices with three and four zeros and find that only
ten matrices with three zeros provide solutions in agreement with data. We
present the successful Yukawa textures including the relative sizes of their
non-zero entries as well as some new and interesting relations among the
entries of these textures in terms of the charged lepton masses. We also show
that these relations can be obtained directly from a parametrization of the
charged lepton mixing matrix .Comment: 16 pages, two figures. A parametrization of the mixing matrix
was introduced to explain observed patterns in textures. References adde
Evaluación de pacientes con fractura de radio distal tratados con fijación percutánea
En fracturas del radio distal existe una tendencia hacia la reducción abierta y fijación interna, sin embargo, el tratamiento mediante reducción cerrada y enclavamiento percutáneo continúa ofreciendo buenos resultados pero es necesaria una terapia física y rehabilitación temprana y adecuada. Material y métodos: Evaluamos a pacientes con fractura de radio distal tratados mediante reducción por maniobras y enclavamiento percutáneo, utilizamos escalas clínicas funcionales como la escala de DASH, la escala de muñeca de la Clínica Mayo y Escala Visual Análoga para valorar dolor. Los resultados de los pacientes fueron comparados a las 12 y 24 semanas. Así mismo comparamos a pacientes con o sin rehabilitación. Resultados: se evaluó a 60 pacientes con la escala DASH, en pacientes con rehabilitación obtuvieron 4.3 puntos, mientras que sin rehabilitación fue de 10.5 puntos (p = 0.00001), en la escala de la Clínica Mayo con rehabilitación tuvieron 86.7 puntos y sin rehabilitación tuvieron 77.8 puntos (p = 0.00001). El EVA no fue significativo. Conclusión: Todos los pacientes mostraron mejoría en sus escalas de evaluación clínica. Sin embargo, al comparar a pacientes con rehabilitación y sin rehabilitación la diferencia fue mayor en la escala de la Clínica Mayo y en la escala de DAS
Correlation between obesity and severity of distal radius fractures
Introduction: The incidence of obesity has increased significantly worldwide. Our hypothesis was that
patients with obesity have a more severe distal radius fracture and we realized a study to evaluate this
correlation between obesity and severity of distal radius fractures caused by low-energy injuries.
Materials and methods: A total of 114 patients with distal radius fracture were examined in
The afterglow and kilonova of the short GRB 160821B
GRB 160821B is a short duration gamma-ray burst (GRB) detected and localized
by the Neil Gehrels Swift Observatory in the outskirts of a spiral galaxy at
z=0.1613, at a projected physical offset of 16 kpc from the galaxy's center. We
present X-ray, optical/nIR and radio observations of its counterpart and model
them with two distinct components of emission: a standard afterglow, arising
from the interaction of the relativistic jet with the surrounding medium, and a
kilonova, powered by the radioactive decay of the sub-relativistic ejecta.
Broadband modeling of the afterglow data reveals a weak reverse shock
propagating backward into the jet, and a likely jet-break at 3.5 d. This is
consistent with a structured jet seen slightly off-axis while expanding into a
low-density medium. Analysis of the kilonova properties suggests a rapid
evolution toward red colors, similar to AT2017gfo, and a low nIR luminosity,
possibly due to the presence of a long-lived neutron star. The global
properties of the environment, the inferred low mass (M_ej < 0.006 Msun) and
velocities (v > 0.05 c) of lanthanide-rich ejecta are consistent with a binary
neutron star merger progenitor.Comment: 14 pages, 6 figures, MNRAS, in press. Moderate revision, added Figure
5 and X-ray data to Table
Primer consenso colombiano sobre Chagas congénito y orientación clínica a mujeres en edad fértil con diagnóstico de Chagas
La transmisión congénita de la enfermedad de Chagas ha sido poco estudiada en Colombia y existen pocos procedimientos rutinarios en el sistema de salud para el manejo de esta enfermedad. Por ello se desarrolló un consenso de expertos dirigido a generar recomendaciones de diagnóstico y tratamiento de Chagas congénito y orientación a mujeres en edad fértil. Con ese propósito se realizó una búsqueda extensiva de la literatura, empleando una combinación de términos Mes (Chagas, Chagas congénito, prevención, control, diagnóstico, tratamiento y embarazo) para reflejar el estado del arte en cada tema de interés. Después de ello, se leyeron los resúmenes y aquellos seleccionados para análisis del texto completo. La literatura relevante se sintetizo, clasifico y organizo en tablas y se presentó al panel de expertos, el cual estaba constituido por 30 profesionales en diferentes áreas. Mediante la metodología Delphi se realizaron 2 rondas de cuestionarios virtuales y una reunión presencial en los cuales se evaluaron los niveles de acuerdo entre los participantes. Los puntos con falta de consenso durante las 2 rondas virtuales se expusieron durante las mesas de discusión en la ronda presencial. La evidencia utilizada se adaptó a las particularidades nacionales según el caso y se aprobó el contenido del documento final. Se propone que estas recomendaciones sean usadas por profesionales de la salud en Colombia.Congenital transmission of Chagas disease has not been extensively studied in Colombia, and there are no standardized processes in the health system regarding the specific diagnosis, treatment and follow-up of this disease. To generate recommendations on congenital Chagas disease and Chagas in women of childbearing age in Colombia, a consensus of experts was developed. An extensive literature search through the Medline database was carried out using the MeSH terms: «Chagas disease/congenital», «prevention and control», «diagnosis», «therapeutics» and «pregnancy». Appropriate abstracts were selected and the full texts were analyzed. The relevant information was synthesized, classified, and organized into tables and figures and was presented to a panel of experts, which was composed of 30 professionals from various fields. Based on the Delphi methodology, three rounds of consultation were conducted. The first and second rounds were based on electronic questionnaires that measured the level of consensus of each question among the participants. The third round was based on a face-to-face discussion focusing on those questions without consensus in the previous consultations. The evidence was adapted to national circumstances on a case-by-case basis, and the content the final document was approved. These recommendations are proposed for use in routine medical practice by health professionals in Colombia
- …