Modelo predictivo del índice de anisotropía del semicoque a partir de las propiedades de los carbones de la Cordillera Oriental de Colombia

This study developed a theoretical model for the determination of the Coke Anisotropy Quotient (CAQ) of semi-coke from the properties of its precursor coal. This is an useful parameter to define the resistance and reactivity of semi-coke in the blast furnace. For 36 semi-coke samples, a textural analysis was performed alongside a fluidity test to determine the real CAQ. The main textures observed were: isotropic and circular for high volatile bituminous coals (HVB); lenticular and fine ribbons for the medium volatile bituminous coals (MVB); and medium and thick ribbons for the low volatile bituminous coals (LVB). The CAQ varied in a range from 1 to 11. A principal component analysis (PCA) and multiple regression allowed to discriminated the importance of certain coal properties, in determining the CAQ to be recognized and to estimate parameters of the mathematical model. The statistical analysis suggested that CAQ can be best predicted from the fluidity, volatile matter, and Ro of the parent coals. The veracity of this model result was then tested using a second dataset from Poland. This work optimizes the usefulness of standard datasets in the prediction of CAQ's offering a means of quality control that could be implemented in Colombian coke production.En esta investigación se desarrolló un modelo teórico para la determinación del Cociente de Anisotropía del Coque (CAQ) del semicoque a partir de las propiedades de su carbón precursor. El CAQ permite definir la resistencia y la reactividad del semicoque en el alto horno. Usando material residual de las pruebas de fluidez se realizó un análisis textural para determinar el CAQ real sobre 36 muestras de semicoque. Las principales texturas observadas para los carbones bituminosos fueron: isotrópicas y circulares para los de alta volatilidad (HVB); cintas lenticulares y finas para los de media volatilidad (MVB); y cintas medias y gruesas para los de baja volatilidad (LVB). El CAQ varió en un rango de 1 a 11. Análisis de componentes principales (PCA) y regresión múltiple permitieron reconocer la importancia de ciertas propiedades del carbón para determinar el CAQ. El análisis estadístico sugirió que el CAQ puede predecirse mejor a partir de la fluidez,la materia volátil y el Ro de los carbones precursores. Este modelo fue validado a través de la comparación con datos reales de carbones de Polonia. Este trabajo proporciona un medio de control de calidad que podríaimplementarse en la producción de coque colombiano.&nbsp

Reflexion critica acerca de las clausulas abusivas en los contratos de adhesion

39 h. ; 28 cm.En este trabajo buscamos esquematizar, a través del método lógico deductivo, los contratos de adhesión y las cláusulas abusivas. En especial de una: la letra g) del artículo 16 Ley de Protección al Consumidor Nº 19.496 modificada por ley 19.955 de 14 de julio de 2004. En el primer capítulo encontraremos algunas definiciones de contrato de adhesión, características y aspectos generales, referencias al nuevo enfoque de la contratación, en especial de la libertad contractual, y por último la interpretación de estos contratos. En el segundo capítulo analizamos las cláusulas abusivas propiamente tales y como son vistas en nuestra doctrina. En el tercer capítulo analizamos la letra g) del artículo 16, especialmente aspectos como la buena fe y el desequilibrio en las prestaciones entre las partes. Por último en el cuarto capítulo nos referiremos a los mecanismos de control de estas cláusulas y remedios que nos ofrece la doctrina para evitarlas

EVALUACIÓN DE LOS ESQUEMAS TARIFARIOS DE ASEO APLICADOS EN COLOMBIA

The study makes an analysis of the tariff schemes developed by the public system of cleaning in Colombia. The article is reflective and analytical in nature, it analyzes several documents issued by the regulatory entity of the cleaning service (Commission for the Regulation of Drinking Water and Basic Sanitation, CRA) related to the tariff issue of cleaning in Colombia with the purpose of looking at the regulatory advances and their effectiveness in the application of these schemes. The cleaning tariff schemes applied in Colombia have been issued under the regime of regulated freedom, they have progressively covered a greater number of activities and have had in common the use of the average cost methodology, using the regulatory technique of ceiling price, combined with the reference cost and price band techniques. The latest Resolution (CRA 853 of 2018) for small providers addresses methodologies for particular situations that arise in the Colombian geographic and social reality and that had not been taken into account in the previous rate schemes such as small providers, rural populated centers, hard-to-reach areas and regional schemes.El estudio hace un análisis de los esquemas tarifarios desarrollados en el servicio público de aseo en Colombia. El artículo es de carácter reflexivo y analítico, se analizan varios documentos expedidos por la entidad reguladora del servicio de aseo (Comisión de Regulación de Agua Potable y Saneamiento Básico, CRA) relacionados con el tema tarifario de aseo en Colombia con el propósito de mirar los avances regulatorios y su efectividad en la aplicación de estos esquemas. Los esquemas tarifarios de aseo aplicados en Colombia, han sido expedidos bajo el régimen de libertad regulada, progresivamente han abarcado una mayor cantidad de actividades y han tenido en común la utilización de la metodología de costo medio, utilizando la técnica regulatoria de precio techo, combinada con las técnicas de costo de referencia y banda de precios. La última Resolución para pequeños prestadores (CRA 853 de 2018) aborda metodologías para situaciones particulares que se presentan en la realidad geográfica y social colombiana y que no habían sido tenidas en cuenta en los anteriores esquemas tarifarios como son pequeños prestadores, centros poblados rurales, áreas de difícil acceso y esquemas regionales

Efectividad y seguridad de tocilizumab en 2 casos de orbitopatía tiroidea grave refractaria a corticosteroides. Hospital San José, Bogotá

La orbitopatía tiroidea es la manifestación extratiroidea más frecuente del hipertiroidismo autoinmune; más del 90 % de los casos se asocian con enfermedad de Graves (EG). Es un trastorno complejo que puede provocar deformidad orbitaria, visión doble e incluso pérdida visual permanente, con gran impacto en la calidad de vida. Aproximadamente, el 2 % de los pacientes que desarrollan orbitopatía de Graves desarrolla enfermedad moderada a grave. Existe una creciente conciencia de la necesidad de un diagnóstico precoz y un manejo oportuno para disminuir las secuelas irreversibles. Su manejo inicial es con glucocorticoides; sin embargo, la recurrencia ocurre con frecuencia una vez que se retiran. En más del 60 % de los casos, la anatomía orbitaria normal no se restaura y se requiere cirugía de rehabilitación. En casos de refractariedad, las terapias biológicas son una alternativa, las cuales han demostrado ser efectivas. Dentro de estas están el teprotumumab, que reduce la proptosis, recientemente aprobado por la Food and Drug Administration (FDA); el rituximab, que reduce la inflamación; y el tocilizumab, que potencialmente beneficia ambos parámetros. A continuación, se describe el efecto del tocilizumab en 2 pacientes con orbitopatía tiroidea en el Hospital San José, en Bogotá

Reimagining pheromone signalling in the model nematode Caenorhabditis elegans

Caenorhabditis elegans is an important, widely used developmental and genetic model. A pheromone has long been known to cause juvenile developmental arrest in C. elegans, a phenomenon that is common among nematodes more widely. Many novel effects of this pheromone are now being discovered—most recently, that exogenous supply of this pheromone controls adult worms reproduction. Here, we suggest that to properly understand and interpret these phenomena, C. elegans natural ecology must be considered, about which rather little is known. With this perspective, we suggest that C. elegans pheromone signalling evolves very locally, such that there are different dialects of pheromone signalling among ecological communities and among kin groups, and we also argue that pheromone signals may also evolve to be manipulative and dishonest. New approaches must be undertaken to study these phenomena in C. elegans. While model systems have been tremendously important tools in modern biological research, taking account of their natural history is necessary, and key, to properly understand and interpret laboratory-based discoveries.understand and interpret laboratory-based discoveries

Arabidopsis leucine-rich repeat receptor–like kinase NILR1 is required for induction of innate immunity to parasitic nematodes

Plant-parasitic nematodes are destructive pests causing losses of billions of dollars annually. An effective plant defence against pathogens relies on the recognition of pathogen-associated molecular patterns (PAMPs) by surface-localised receptors leading to the activation of PAMP-triggered immunity (PTI). Extensive studies have been conducted to characterise the role of PTI in various models of plant-pathogen interactions. However, far less is known about the role of PTI in roots in general and in plant-nematode interactions in particular. Here we show that nematode-derived proteinaceous elicitor/s is/are capable of inducing PTI in Arabidopsis in a manner dependent on the common immune co-receptor BAK1. Consistent with the role played by BAK1, we identified a leucine-rich repeat receptor-like kinase, termed NILR1 that is specifically regulated upon infection by nematodes. We show that NILR1 is essential for PTI responses initiated by nematodes and nilr1 loss-of-function mutants are hypersusceptible to a broad category of nematodes. To our knowledge, NILR1 is the first example of an immune receptor that is involved in induction of basal immunity (PTI) in plants or in animals in response to nematodes. Manipulation of NILR1 will provide new options for nematode control in crop plants in future

Tomato TFT1 Is Required for PAMP-Triggered Immunity and Mutations that Prevent T3S Effector XopN from Binding to TFT1 Attenuate Xanthomonas Virulence

XopN is a type III effector protein from Xanthomonas campestris pathovar vesicatoria that suppresses PAMP-triggered immunity (PTI) in tomato. Previous work reported that XopN interacts with the tomato 14-3-3 isoform TFT1; however, TFT1's role in PTI and/or XopN virulence was not determined. Here we show that TFT1 functions in PTI and is a XopN virulence target. Virus-induced gene silencing of TFT1 mRNA in tomato leaves resulted in increased growth of Xcv ΔxopN and Xcv ΔhrpF demonstrating that TFT1 is required to inhibit Xcv multiplication. TFT1 expression was required for Xcv-induced accumulation of PTI5, GRAS4, WRKY28, and LRR22 mRNAs, four PTI marker genes in tomato. Deletion analysis revealed that the XopN C-terminal domain (amino acids 344–733) is sufficient to bind TFT1. Removal of amino acids 605–733 disrupts XopN binding to TFT1 in plant extracts and inhibits XopN-dependent virulence in tomato, demonstrating that these residues are necessary for the XopN/TFT1 interaction. Phos-tag gel analysis and mass spectrometry showed that XopN is phosphorylated in plant extracts at serine 688 in a putative 14-3-3 recognition motif. Mutation of S688 reduced XopN's phosphorylation state but was not sufficient to inhibit binding to TFT1 or reduce XopN virulence. Mutation of S688 and two leucines (L64,L65) in XopN, however, eliminated XopN binding to TFT1 in plant extracts and XopN virulence. L64 and L65 are required for XopN to bind TARK1, a tomato atypical receptor kinase required for PTI. This suggested that TFT1 binding to XopN's C-terminal domain might be stabilized via TARK1/XopN interaction. Pull-down and BiFC analyses show that XopN promotes TARK1/TFT1 complex formation in vitro and in planta by functioning as a molecular scaffold. This is the first report showing that a type III effector targets a host 14-3-3 involved in PTI to promote bacterial pathogenesis

TESS Cycle 1 observations of roAp stars with 2-min cadence data

We present the results of a systematic search for new rapidly oscillating Ap (roAp) stars using the 2-min cadence data collected by the Transiting Exoplanet Survey Satellite (TESS) during its Cycle 1 observations. We identify 12 new roAp stars. Amongst these stars we discover the roAp star with the longest pulsation period, another with the shortest rotation period, and six with multiperiodic variability. In addition to these new roAp stars, we present an analysis of 44 known roAp stars observed by TESS during Cycle 1, providing the first high-precision and homogeneous sample of a significant fraction of the known roAp stars. The TESS observations have shown that almost 60 per cent (33) of our sample of stars are multiperiodic, providing excellent cases to test models of roAp pulsations, and from which the most rewarding asteroseismic results can be gleaned. We report four cases of the occurrence of rotationally split frequency multiplets that imply different mode geometries for the same degree modes in the same star. This provides a conundrum in applying the oblique pulsator model to the roAp stars. Finally, we report the discovery of non-linear mode interactions in $\alpha$ Cir (TIC 402546736, HD 128898) around the harmonic of the principal mode -- this is only the second case of such a phenomenon...

Rotation and pulsation in Ap stars: first light results from TESS sectors 1 and 2

We present the first results from the Transiting Exoplanet Survey Satellite (TESS) on the ro- tational and pulsational variability of magnetic chemically peculiar A-type stars. We analyse TESS 2-min cadence data from sectors 1 and 2 on a sample of 83 stars. Five new rapidly oscillating Ap (roAp) stars are announced. One of these pulsates with periods around 4.7 min, making it the shortest period roAp star known to date. Four out of the five new roAp stars are multiperiodic. Three of these, and the singly-periodic one show the presence of rotational mode splitting. Individual frequencies are provided in all cases. In addition, seven previously known roAp stars are analysed. Additional modes of oscillation are found in some stars, while in others we are able to distinguish the true pulsations from possible aliases present in the ground-based data. We find that the pulsation amplitude in the TESS filter is typically a factor 6 smaller than that in the B filter which is usually used for ground-based observations. For four roAp stars we set constraints on the inclination angle and magnetic obliquity, through the application of the oblique pulsator model. We also confirm the absence of roAp-type pulsa- tions down to amplitude limits of 6 and 13 µmag, respectively, in two of the best characterised non-oscillating Ap (noAp) stars. We announce 27 new rotational variables along with their ro- tation periods, and provide different rotation periods for seven other stars. Finally, we discuss how these results challenge state-of-the-art pulsation models for roAp stars