U(2) Flavor Physics without U(2) Symmetry

We present a model of fermion masses based on a minimal, non-Abelian discrete symmetry that reproduces the Yukawa matrices usually associated with U(2) theories of flavor. Mass and mixing angle relations that follow from the simple form of the quark and charged lepton Yukawa textures are therefore common to both theories. We show that the differing representation structure of our horizontal symmetry allows for new solutions to the solar and atmospheric neutrino problems that do not involve modification of the original charged fermion Yukawa textures, or the introduction of sterile neutrinos.Comment: 12 pages RevTeX, 1 eps figure. A few typos correcte

Sistema guía para personas con deficiencia visual

En este artículo se presenta un sistema guía para personas con deficiencia visual basado en la construcción de un dispositivo electrónico de sensado, una aplicación móvil cliente y la comunicación y sincronización entre las partes. Este producto ayudará a las personas que padecen esta patología a desenvolverse independientemente en su entorno, ya que detecta la presencia de objetos que obstaculizan el desplazamiento. La aplicación corre en un dispositivo móvil y se adapta a las necesidades de cada usuario. El sistema incluye la construcción de un dispositivo con sensores ultrasónicos de distancia desarrollado con tecnología PIC, el cual se comunica con una aplicación móvil desarrollada en Java para Android que se ejecuta en un teléfono celular. Se utiliza el paradigma de programación orientado a objetos para el desarrollo de la aplicación debido a que permite la reutilización y extensión del código. De acuerdo a las pruebas funcionales realizadas, es factible la implementación exitosa del sistema.V Workshop innovación en sistemas de softwareRed de Universidades con Carreras en Informática (RedUNCI

Gestión de la toma de decisiones en una empresa dedicada a la asesoría empresarial, Lima, 2022

El presente estudio tuvo como objetivo identificar la relación que existe entre la gestión de toma de decisiones y sus tres dimensiones: Capacidad profesional, Tipos de modelos de toma de decisiones y Conocimiento del mercado actual para una empresa dedicada a la asesoría empresarial. En cuanto a la metodología, esta investigación fue aplicada, con un diseño no experimental, de corte transversal descriptivo simple. También, se usó el método hipotético-deductivo para contrastar las hipótesis que fundamentaron esta investigación. Asimismo, tuvo un enfoque cuantitativo con un nivel descriptivo-relacional siendo aplicada a través de un cuestionario de Likert a 31 directivos del rubro. Para la prueba de confiabilidad de los datos, se usó el Alfa de Cronbach mediante el software SPSS v.26, el cual arrojó un valor de 0.910. Como resultado se obtuvo que la variable tuvo una relación positiva con respecto a sus 3 dimensiones (p< 0.05), capacidad profesional CD=30.25%, tipo de modelos CD=26.94% y el conocimiento del mercado CD=29.59%. En conclusión, la gestión de toma de decisiones dentro de la empresa dedicada a la asesoría empresarial tuvo una relación significativa con cada una de sus dimensiones

A new 'saccamminid' genus (Rhizaria: Foraminifera), from 4400 m water depth in the Nazare Canyon (NE Atlantic)

We describe Bithekammina occulta, a new monothalamous agglutinated foraminiferan ('saccamminid') collected in multicore samples at 4400 m on the terrace of the lower Nazare Canyon on the Portuguese margin. The test is spherical to oval, up to similar to 400 mu m in length, with a simple circular aperture. The wall has a very smooth surface with a distinct sheen in reflected light. It is <10 mu m thick and composed of very fine agglutinated plate-like clay particles and a thin inner organic layer. The most distinctive feature of the new species is that the test is contained within an agglutinated case ('secondary test') composed mainly of larger (10-50 mu m) quartz grains. The case is equipped with a long, narrow tube that originates near the aperture of the inner test and presumably acts as a channel through which pseudopodia are deployed. Secondary agglutinated structures have been described in a number of foraminifera, but never before in a 'saccamminid'.EC FP6 GOCE-CT-2005–511234 HERMESEC FP7 - 226354 HERMIONEFCT - PTDC/MAR/110082/2009 DeepForamsFCT - SFRH/BPD/26272/200

Constraints on Natural MNS Parameters from |U_e3|

The MNS matrix structure emerging as a result of recent neutrino measurements strongly suggests two large mixing angles (solar and atmospheric) and one small angle (|U_e3| << 1). Especially when combined with the neutrino mass hierarchy, these values turn out to impose rather stringent constraints on possible flavor models connecting the three active fermion generations. Specifically, we show that an extremely small value of |U_e3| would require fine tuning of Majorana mass matrix parameters, particularly in the context of seesaw models.Comment: 21 pages, ReVTeX, 2 .eps figure files, updated references and acknowledgment

Influence of silver electrochemically deposited onto zinc oxide seed nanoparticles on the photoelectrochemical performance of zinc oxide nanorod films

The present article examines the synthesis and characterization of zinc oxide nanorods grown on zinc oxide and silver nanoparticle seeds. Zinc oxide seeds were electrodeposited on a support of fluorine-doped tin oxide glass and heat-treated at 380°C. Silver nanoparticles were then deposited on this substrate, which was heat-treated at 160°C. Their presence was confirmed using ultraviolet–visible spectroscopy, by observing an absorption peak around 400 nm, corresponding to surface plasmon resonance. Growth of zinc oxide nanorods was achieved in a chemical bath at 90°C. The obtained films were analyzed by cyclic voltammetry, X-ray diffraction, and scanning electron microscopy. They consisted of zinc oxide with a Wurtzite-type crystal structure, arranged as nanorods of 50 nm. X-ray photoelectron spectroscopy exhibits peaks attributed to silver (0) and to the formation of silver oxide on the silver nanoparticle surface. In addition, two types of oxygen (O 1 s) were observed: oxygen from the crystalline network (O–2) and chemisorbed oxygen (–OH), for the seed and the nanorod films, respectively. The nanorods grown on zinc oxide seeds with silver deposits had a round shape and greater photoactivity than those grown without silver. This difference is attributed to the additional reflection that silver provides to the light reaching the film, thereby increasing the photogeneration from the charge carriers.Fil: Aranda, Alejandro. Universidad Nacional de Ingeniería. Facultad de Ciencias. Laboratorio de Materiales Nanoestructurados; PerúFil: Landers, Richard. Universidade Estadual de Campinas; BrasilFil: Carnelli, Patricio Francisco Florencio. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Candal, Roberto Jorge. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Alarcón, Hugo. Universidad Nacional de Ingeniería. Facultad de Ciencias. Laboratorio de Materiales Nanoestructurados; PerúFil: Rodríguez, Juan. Universidad Nacional de Ingeniería. Facultad de Ciencias. Laboratorio de Materiales Nanoestructurados; Per

Tribimaximal Neutrino Mixing from A_4 Replication

Motivated by dimensional deconstruction, we propose a model of tribimaximal neutrino mixing based on A_4 x A_4 symmetry. In this model, the two triplet symmetry-breaking fields of conventional A_4 models are taken to transform under different A_4 group factors, but are not distinguished by any other quantum numbers. An additional bi-triplet flavon field breaks A_4 x A_4 to its diagonal subgroup. If the bi-triplet transforms under an additional Z_3 symmetry, we show that one can construct a general, renormalizable superpotential that yields the desired pattern of symmetry breaking. We identify the features that this model has in common with a deconstructed 5D theory in which A_4 is a subgroup of a continuous gauged flavor symmetry in the bulk.Comment: 13 pages LaTeX (v2: discussion added

The effects of iron fortification on the gut microbiota in African children: a randomized controlled trial in Cote d'Ivoire.

BACKGROUND: Iron is essential for the growth and virulence of many pathogenic enterobacteria, whereas beneficial barrier bacteria, such as lactobacilli, do not require iron. Thus, increasing colonic iron could select gut microbiota for humans that are unfavorable to the host. OBJECTIVE: The objective was to determine the effect of iron fortification on gut microbiota and gut inflammation in African children. DESIGN: In a 6-mo, randomized, double-blind, controlled trial, 6-14-y-old Ivorian children (n = 139) received iron-fortified biscuits, which contained 20 mg Fe/d, 4 times/wk as electrolytic iron or nonfortifoed biscuits. We measured changes in hemoglobin concentrations, inflammation, iron status, helminths, diarrhea, fecal calprotectin concentrations, and microbiota diversity and composition (n = 60) and the prevalence of selected enteropathogens. RESULTS: At baseline, there were greater numbers of fecal enterobacteria than of lactobacilli and bifidobacteria (P < 0.02). Iron fortification was ineffective; there were no differences in iron status, anemia, or hookworm prevalence at 6 mo. The fecal microbiota was modified by iron fortification as shown by a significant increase in profile dissimilarity (P < 0.0001) in the iron group as compared with the control group. There was a significant increase in the number of enterobacteria (P < 0.005) and a decrease in lactobacilli (P < 0.0001) in the iron group after 6 mo. In the iron group, there was an increase in the mean fecal calprotectin concentration (P < 0.01), which is a marker of gut inflammation, that correlated with the increase in fecal enterobacteria (P < 0.05). CONCLUSIONS: Anemic African children carry an unfavorable ratio of fecal enterobacteria to bifidobacteria and lactobacilli, which is increased by iron fortification. Thus, iron fortification in this population produces a potentially more pathogenic gut microbiota profile, and this profile is associated with increased gut inflammation. This trial was registered at controlled-trials.com as ISRCTN21782274

Maximal Neutrino Mixing from a Minimal Flavor Symmetry

We study a number of models, based on a non-Abelian discrete group, that successfully reproduce the simple and predictive Yukawa textures usually associated with U(2) theories of flavor. These models allow for solutions to the solar and atmospheric neutrino problems that do not require altering successful predictions for the charged fermions or introducing sterile neutrinos. Although Yukawa matrices are hierarchical in the models we consider, the mixing between second- and third-generation neutrinos is naturally large. We first present a quantitative analysis of a minimal model proposed in earlier work, consisting of a global fit to fermion masses and mixing angles, including the most important renormalization group effects. We then propose two new variant models: The first reproduces all important features of the SU(5)xU(2) unified theory with neither SU(5) nor U(2). The second demonstrates that discrete subgroups of SU(2) can be used in constructing viable supersymmetric theories of flavor without scalar universality even though SU(2) by itself cannot.Comment: 34 pages LaTeX, 1 eps figure, minor revisions and references adde