Angular emission properties of a layer of rare-earth based nanophosphors embedded in one-dimensional photonic crystal coatings

The angular properties of light emitted from rare-earth based nanophosphors embedded in optical resonators built in one-dimensional photonic crystal coatings are herein investigated. Strong directional dependence of the photoluminescence spectra is found. Abrupt angular variations of the enhancement caused by the photonic structure and the extraction power are observed, in good agreement with calculated polar emission patterns. Our results confirm that the optical cavity favors the extraction of different wavelengths at different angles and that integration of nanophosphors within photonic crystals provides control over the directional emission properties that could be put into practice in phosphorescent displays.Ministerio de Ciencia e Innovación MAT2008- 02166, CSD2007-00007Junta de Andalucía FQM3579, FQM524

A Vector Non-abelian Chern-Simons Duality

Abelian Chern-Simons gauge theory is known to possess a `$S$-self-dual' action where its coupling constant $k$ is inverted {\it i.e.} $k \leftrightarrow {1 \over k}$. Here a vector non-abelian duality is found in the pure non-abelian Chern-Simons action at the classical level. The dimensional reduction of the dual Chern-Simons action to two-dimensions constitutes a dual Wess-Zumino-Witten action already given in the literature.Comment: 14+1 pages, LaTeX file, no figures, version to appear in Phys. Rev

Composición química y mineralogía de las Biotitas Metamórficas del sector central del Macizo de Santander, Colombia.

Las biotitas metamórficas de las formaciones Neis de Bucaramanga, Silgará y Ortoneis en el Sector Central del Macizo de Santander corresponden a la serie eastonita-siderofilita y annita. La composición química de la biotita en metapelitas varía con relación al grado de metamorfismo, mientras que en las rocas cuarzofeldespáticas y máficas, el quimismo de las biotitas esta condicionado por la composición del protolito.The metamorphic biotites of the Neis de Bucaramanga, Silgará and Ortoneis formations in the Central Part of the Santander Massif correspond to the eastonite-siderofilite and annite series. The chemical composition of the biotite in metapelites depends on the temperature and pressure, while in quartz feldspathic and mafic rocks it is controlated by the bulk rock composition of the protolith

Composición química y mineralogía de las Biotitas Metamórficas del sector central del Macizo de Santander, Colombia.

Las biotitas metamórficas de las formaciones Neis de Bucaramanga, Silgará y Ortoneis en el Sector Central del Macizo de Santander corresponden a la serie eastonita-siderofilita y annita. La composición química de la biotita en metapelitas varía con relación al grado de metamorfismo, mientras que en las rocas cuarzofeldespáticas y máficas, el quimismo de las biotitas esta condicionado por la composición del protolito.The metamorphic biotites of the Neis de Bucaramanga, Silgará and Ortoneis formations in the Central Part of the Santander Massif correspond to the eastonite-siderofilite and annite series. The chemical composition of the biotite in metapelites depends on the temperature and pressure, while in quartz feldspathic and mafic rocks it is controlated by the bulk rock composition of the protolith

Empleo del azúcar en la alimentación de aves.

El azúcar presenta un alto contenido de energía metabolizable 3.733 Kcal/kg, este hecho unido a la circunstancia de presentarse excedentes en su producción en el país, lo convierte en una materia prima atractiva para la formulación de raciones para aves a mínimo costo. Investigaciones realizadas en Colombia sobre el empleo del azúcar en dietas para pollos de engorde y ponedoras, confirman el mayor nivel de inclusión entre 20 y 30 por ciento. Con niveles superiores del 450 por ciento es necesario fortificar la premezcla con vitaminas del complejo B. A nivel industrial se ve limitado el porcentaje de uso del azúcar debido a la dificultad que ofrece este producto en el proceso de peletización de los alimentos, obligando a suministrar las dietas en forma de harina. El comportamiento zootécnico de las aves ha sido satisfactorio a nivel comercial, cuando se reeplazan, como fuente energética en la dieta, cereales por azúcar. El empleo del azúcar en el momento de la recepción al día de edad de los pollos de engorde y pollitas de reemplazo, solución de azúcar el 10 por ciento en agua durante 12.24 horas, mejora su ganancia de peso y conversión alimenticia y previene problemas de impactación de los pollitos, en relación con las aves que reciben agua únicamente, asegurando desde un comienzo el éxito económico del lot

The Coronal Structure of AB Doradus

We perform a numerical simulation of the corona of the young, rapidly rotating K0 dwarf AB Doradus using a global MHD model. The model is driven by a surface map of the radial magnetic field constructed using Zeeman-Doppler Imaging. We find that the global structure of the stellar corona is dominated by strong azimuthal tangling of the magnetic field due to the rapid rotation. The MHD solution enables us to calculate realistic Alfv\'en surfaces and we can therefore estimate the stellar mass loss rate and angular momentum loss rate without making undue theoretical simplifications. We consider three cases, parametrized by the base density of the corona, that span the range of possible solutions for the system. We find that overall, the mass and angular-momentum loss rates are higher than in the solar case; the mass loss rates are 10 to 500 times higher, and the angular momentum loss rate can be up to $3\times{10}^4$ higher than present day solar values. Our simulations show that this model can be use to constrain the wide parameter space of stellar systems. It also shows that an MHD approach can provide more information about the physical system over the commonly used potential field extrapolation.Comment: 13 pages, 7 figure

Gravitational Duality in MacDowell-Mansouri Gauge Theory

Strong-weak duality invariance can only be defined for particular sectors of supersymmetric Yang-Mills theories. Nevertheless, for full non-Abelian non-supersymmetric theories, dual theories with inverted couplings, have been found. We show that an analogous procedure allows to find the dual action to the gauge theory of gravity constructed by the MacDowell-Mansouri model plus the superposition of a $\Theta$ term.Comment: 9 pages, LaTeX, no figure

Environmentally responsive nanoparticle-based luminescent optical resonators

In this work, we demonstrate that optical resonators built using all-nanoparticle-based porous building blocks provide a responsive multifunctional matrix, totally different emission spectra being attained from the same embedded luminescent nanophosphors under varying environmental conditions. We show a clear correlation between modifications in the ambient surroundings, the induced changes of the resonant modes, and the resulting variations in the emission response. The method is versatile and allows nanophosphors of arbitrary shape to be integrated in the cavity. By precise control of the spectral features of the optical resonances, luminescence is strongly modulated in selected and tuneable wavelength ranges. Applications in the fields of sensing and detection are foreseen for these materialsEspaña Ministerio de Ciencia e Innovación MAT2008-02166 CONSOLIDER HOPE CSD2007-00007Junta de Andalucía FQM357

Tissue remodelling and increased DNA damage in patients with incompetent valves in chronic venous insufficiency

Chronic venous insufficiency (CVI), in which blood return to the heart is impaired, is a prevalent condition worldwide. Valve incompetence is a complication of CVI that results in blood reflux, thereby aggravating venous hypertension. While CVI has a complex course and is known to produce alterations in the vein wall, the underlying pathological mechanisms remain unclear. This study examined the presence of DNA damage, pro-inflammatory cytokines and extracellular matrix remodelling in CVI-related valve incompetence. One hundred and ten patients with CVI were reviewed and divided into four groups according to age (<50 and ≥50 years) and a clinical diagnosis of venous reflux indicating venous system valve incompetence (R) (n = 81) or no reflux (NR) (n = 29). In vein specimens (greater saphenous vein) from each group, PARP, IL-17, COL-I, COL-III, MMP-2 and TIMP-2 expression levels were determined by RT-qPCR and immunohistochemistry. The younger patients with valve incompetence showed significantly higher PARP, IL-17, COL-I, COL-III, MMP-2 and reduced TIMP-2 expression levels and a higher COL-I/III ratio. Young CVI patients with venous reflux suffer chronic DNA damage, with consequences at both the local tissue and systemic levels, possibly associated with ageing.This study (FIS-PI18/00912) was supported by the Instituto de Salud Carlos III (Plan Estatal de I + D+i 2013-2016) and co-financed by the European Development Regional Fund “A way to achieve Europe” (ERDF) and B2017/BMD-3804 MITIC-CM