Analysis of the quark sector in the 2HDM-III with a four-zero Yukawa texture using the most recent data on the CKM matrix

In this letter we analyse, in the context of the general 2-Higgs Doublet Model, the structure of the Yukawa matrices, $\widetilde{ \bf Y}_{ _{1,2} }^{q}$, by assuming a four-zero texture ansatz for their definition. In this framework, we obtain compact expressions for $\widetilde{ \bf Y}_{ _{1,2} }^{q}$, which are reduced to the Cheng and Sher ansatz with the difference that they are obtained naturally as a direct consequence of the invariants of the fermion mass matrices. Furthermore, in order to avoid large flavour violating effects coming from charged Higgs exchange, we consider the main flavour constraints on the off-diagonal terms of Yukawa texture {{$\left( \widetilde{\chi}_{j}^q \right)_{kl}$}} ($k\neq l$). We perform a $\chi^2$-fit based on current experimental data on the quark masses and the Cabibbo-Kobayashi-Maskawa mixing matrix ${ \bf V}_{\rm CKM }$. Hence, we obtain the allowed ranges for the parameters $\widetilde{ \bf Y}_{ _{1,2} }^{q}$ at 1$\sigma$ for several values of $\tan \beta$. The results are in complete agreement with the bounds obtained taking into account constraints on Flavour Changing Neutral Currents reported in the literature.Comment: 12 pages, 1 figure. Version accepted in Phys. Lett.

Lesiones esqueléticas asociadas al síndrome de Papillon-Lefèvre

Se presentan dos casos de Síndrome de Papillon-Lefèvre que se asocian a osteolisis espontánea de los metatarsianos y las falanges de los dedos de los pies. Esta asociación no había sido descrita con anterioridad.Two case s of Papillon-Lefèvre syndrome associated with spontaneous osteolysis of the phalanges and metatarsals of the toe s are presented. This association has not been previously reported

Luxación traumática bilateral de cadera

Se presenta un caso de luxación bilateral simultánea de caderas, una anterior y otra posterior, asociada a fractura del acetábulo derecho, fractura de la diáfisis femoral derecha y una subluxación del raquis cervical.A case of simultaneous bilateral anterior and posterior dislocation of the hip joints associated with a fracture of the right acetabulum and right femoral shaft, and a subluxation of the cervical spine, is reported

Contaminación natural por aflatoxina B1 en alimentos terminados para aves.

Con el fin de conocer la contaminación natural por aflatoxina B1, se analizaron 120 muestras de alimentos terminados utilizados en avicultura, del tipo engorde iniciación, engorde finalización y postura, producidos por cuatro fábricas de alimentos concentrados para uso animal. Se encontró una contaminación del 54.2 por ciento con un rango de concentración de aflatoxina B1 que fluctuó entre 1.5 y más de 30 partes por billon (ppb), no obstante la mayoría de las muestras preseantaron niveles inferiores a 20 ppb, nivel máximo permisible establecido en la mayoría de los paises para los alimentos terminados empleados en avicultura. Los resultados confirman investigaciones anteriores y revelan una deficiente control de calidad de estos productos considerandose que las concentraciones encontradas pueden afectar la salud de las ave

A tetraiodo cuprate NHC-MIC biscarbene proligand: coordination chemistry and preliminary catalysis

La preparación de una sal híbrida conteniendo cationes imidazolio/triazolio [NHC-MIC]²+ fue llevada a cabo en tres pasos sintéticos utilizando la cicloadición de azida-alquino catalizada por cobre (CuAAC) y la subsecuente N-metilación del 1,2,-3 triazol. Deprotonación selectiva de la sal mixta con NaH en presencia de un precursor metálico (M= Pd, Rh) permite la síntesis de NHC-metálicos conteniendo fragmentos catiónicos de tipo triazolio [NHC∙(M)-MIC]+. La subsecuente deprotonación del triazolio con KOᵗBu en presencia de Mpermite entonces la síntesis de complejos inusuales tipo quelato conteniendo carbenos clásicos tipo NHC y carbenos mesoiónicos MIC con estructura general [NHC∙(M)∙MIC]+MX₂-. Todos los compuestos han sido caracterizados mediante RMN de ¹H y ¹³C, FT-IR y cristalografía de rayos-X de monocristal. Estudios catalíticos preliminares de los nuevos complejos en procesos de formación de α-cetoamidas serán discutidos.A novel linked imidazolium/triazolium salt [NHC-MIC]²+ was preparedin three synthetic stepsusing copper catalyzed alkyne azide cycloaddition (CuAAC) and N-methylation protocols. Metallation of the imidazolium moiety using KHMDS in presence of a metallic precursor (M = Pd, Rh) yields NHC-anchored/pendent triazolium species [NHC∙(M)-MIC]+ in good yields. The subsequent deprotonation of the triazolium fragment with KOᵗBu in presence of one equivalent of M delivers the rare chelating mixed classical NHC/mesionic biscarbene complexes with the general formula [NHC∙(M)∙MIC]+MX₂-. All the complexes were fully characterized by ¹H and ¹³C NMR, FT-IR and single crystal X-ray diffraction. Preliminary catalytic performances of the new complexes in the oxidativepreparation of α-ketoamides will be discussed

Time Variability in Simulated Ultracompact and Hypercompact HII Regions

Ultracompact and hypercompact HII regions appear when a star with a mass larger than about 15 solar masses starts to ionize its own environment. Recent observations of time variability in these objects are one of the pieces of evidence that suggest that at least some of them harbor stars that are still accreting from an infalling neutral accretion flow that becomes ionized in its innermost part. We present an analysis of the properties of the HII regions formed in the 3D radiation-hydrodynamic simulations presented by Peters et al. as a function of time. Flickering of the HII regions is a natural outcome of this model. The radio-continuum fluxes of the simulated HII regions, as well as their flux and size variations are in agreement with the available observations. From the simulations, we estimate that a small but non-negligible fraction (~ 10 %) of observed HII regions should have detectable flux variations (larger than 10 %) on timescales of ~ 10 years, with positive variations being more likely to happen than negative variations. A novel result of these simulations is that negative flux changes do happen, in contrast to the simple expectation of ever growing HII regions. We also explore the temporal correlations between properties that are directly observed (flux and size) and other quantities like density and ionization rates.Comment: Monthly Notices of the Royal Astronomical Society, in press. The movie of free-free optical depth can be found at http://www.ita.uni-heidelberg.de/~tpeters/tau.av

Análisis cualitativo de plaguicidas clorados, fosforados y carbamatos en muestras de alimentos para aves, recolectadas en Bogotá.

Con el objeto de establecer cualitativamente el grado de contaminación por los grupos de plaguicidas clorados, fosforados y carbamatos en alimentos terminados para aves, se analizaron 120 muestras recolectadas en Bogotá de las 4 fábricas más representativas de esta industria, a razón de 40 muestras para los tipos de engorde iniciación, engorde finalización y postura, se encontraron los siguientes porcentajes de muestras contaminadas : 58.3 por ciento por el grupo de los carbamatos, 99.2 por ciento por el de los clorados y 10.0 por ciento por los fosforados. La mayoría de las muestras presentaron un nivel bajo de contaminación por carbamatos (43 de 70). Los fosforados se encontraron contaminando únicamente el alimento tipo engorde, con niveles de contaminación bajos y medios (4 de 12 y 8 de 12, respectivamente), y la mayor parte de las muestras presentaron un nivel alto de contaminación por compuestos organo-clorados (82 de 119). Estos resultados coinciden con algunos obtenidos previamente y permiten recomendar la necesidad de realizar estudios tendientes a cuantificar todos y cada uno de los contaminantes involucrados, para así poder establecer su repercusión sobre la salud de las avesAvicultur

AGRONOMIC EVALUATION AND CHEMICAL COMPOSITION OF AFRICAN STAR GRASS (Cynodon plectostachyus) IN THE SOUTHERN REGION OF THE STATE OF MEXICO

African Star Grass is one of the forage resources most commonly used by farmers in regions with warm-humid climates. This study was carried out to determine the nutritional and agronomic characteristics of African Star Grass (Cynodon plectostachyus) through the following variables: crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), organic matter digestibility (OMD), net forage accumulation (NFA), stem:leaf ratio, and live:dead matter ratio in the three pastures evaluated. The work took place from April 2007 to March 2008, with evaluations carried out on a monthly basis. The data were analyzed in a randomized block design in which the blocks were the pastures, and the treatments were the months of evaluation. There were no differences between the pastures evaluated for the NDF, ADF or OMD (P>0.05). Differences were found, however, in CP, while in the monthly evaluation, differences were found between the periods evaluated (P<0.05) for these variables. Differences were also found in the agronomic evaluation of pastures (P<0.05) among height of pasture, net forage accumulation (NFA), live matter, dead matter, leaf and stem, both among pastures and in the monthly evaluations. African Star Grass can therefore be considered a good choice for milk production systems in the southern region of the state of Mexico, due to its nutritional and agronomic characteristics