SHEDDING LIGHT ON THE ROLE OF OPAQUE1 IN ASYMMETRIC CELL DIVISION IN MAIZE

Asymmetric cell division (ACD) is important for cell fate and tissue patterning. Many aspects of ACD in plants, however, are still unclear. The process of ACD can be broadly broken down into three phases: (1) cell polarization, (2) division plane establishment and maintenance, and (3) cell division and cytokinesis. Stomatal development in maize has proven to be a useful model for understanding the ACD mechanism. Previous studies have identified several proteins important for all three phases of ACD. Actin is important in each of the phases of ACD, suggesting an actin motor such as myosin may also be important for ACD. Opaque1 (O1) was previously identified as a gene encoding a maize myosin XI important for protein body localization in seeds (G. Wang et al., 2012). The role of O1 in ACD in maize stomata was investigated. Asymmetric stomata divisions were abnormal in o1 mutants; however asymmetrically dividing cells in o1 mutants polarize normally. This suggests O1 is required for ACD but may not be important for cell polarization. Multiple defects in microtubule-based cell division structures, which are important for division plane establishment and cytokinesis, were observed in the o1 mutant. O1 localizes to a plant-specific cell division structure, the phragmoplast, in asymmetrically and symmetrically dividing cells. Together this data suggest that O1 plays multiple roles in asymmetrically dividing cells

Historia del derecho natural y de gentes

Edición y Nota al texto de Manuel Martínez Neir

Influence of MWCNT/surfactant dispersions on the mechanical properties of Portland cement pastes

This work studies the reinforcing effect of Multi Walled Carbon Nanotubes (MWCNT) on cement pastes. A 0.35% solid concentration of MWCNT in powder was dispersed in deionized water with sodium dodecyl sulfate (cationic surfactant), cetylpyridinium chloride (anionic surfactant) and triton X-100 (amphoteric surfactant) using an ultrasonic tip processor. Three concentrations of each surfactant (1mM, 10mM and 100mM) were tested, and all samples were sonicated until an adequate dispersion degree was obtained. Cement pastes with additions of carbon nanotubes of 0.15% by mass of cement were produced in two steps; first the dispersions of MWCNT were combined with the mixing water using an ultrasonic tip processor to guarantee homogeneity, and then cement was added and mixed until a homogeneous paste was obtained. Direct tensile strength, apparent density and open porosity of the pastes were measured after 7 days of curing. It was found that the MWCNT/surfactants dispersions decrease the mechanical properties of the cement based matrix due to an increased porosity caused by the presence of surfactants. © Published under licence by IOP Publishing Ltd

Analytical Expressions for Radiative Opacities of Low Z Plasmas

In this work we obtain analytical expressions for the radiative opacity of several low Z plasmas (He, Li, Be, and B) in a wide range of temperatures and densities. These formulas are obtained by fitting the proposed expression to mean opacities data calculated by using the code ABAKO/ RAPCAL. This code computes the radiative properties of plasmas, both in LTE and NLTE conditions, under the detailed-level-accounting approach. It has been successfully validated in the range of interest in previous works

Conocimientos y actitudes ante la Voluntad Anticipada en profesionales de la salud del Centro Médico “Lic. Adolfo López Mateos”, Toluca, México

Introducción: La Voluntad Anticipada es una declaración mediante la cual una persona mayor de edad, con capacidad mental suficiente y libremente, expone las instrucciones que se deben tener en cuenta respecto a la atención sanitaria que desea recibir en situaciones en las cuales no pueda ya expresar personalmente su voluntad. Objetivo: Determinar el nivel de conocimientos y actitudes que tienen los profesionales de la salud de Centro Médico “Lic. Adolfo López Mateos” con respecto a la Ley de Voluntad Anticipada del Estado de México. Método y materiales: Se aplicaron 265 encuestas que incluían el conocimiento y la actitud que tienen los profesionales de la salud sobre la Ley de Voluntad Anticipada del Estado de México. Resultados: El grupo mayoritario abarcó de 25-29 años con el 31%, el turno mayoritario fue el de la Jornada Especial con 34%, el 60% de los encuestados fueron mujeres y 40% hombres, el 94% no había leído la Ley de Voluntad Anticipada inscrita en la gaceta oficial del Gobierno del Estado de México y el 6% restante respondió afirmativamente. Conclusiones: La mayoría de los y las profesionales de salud refirieron no conocer la Ley inscrita en la gaceta oficial, lo que significa que hace falta difusión y promoción del tema; a pesar de eso, tuvieron una posición favorable hacia la voluntad anticipada y demostraron tener noción sobre lo tratad

A cosmological dust model with extended f(chi) gravity

Introducing a fundamental constant of nature with dimensions of acceleration into the theory of gravity makes it possible to extend gravity in a very consistent manner. At the non-relativistic level a MOND-like theory with a modification in the force sector is obtained, which is the limit of a very general metric relativistic theory of gravity. Since the mass and length scales involved in the dynamics of the whole universe require small accelerations of the order of Milgrom's acceleration constant a_0, it turns out that the relativistic theory of gravity can be used to explain the expansion of the universe. In this work it is explained how to use that relativistic theory of gravity in such a way that the overall large-scale dynamics of the universe can be treated in a pure metric approach without the need to introduce dark matter and/or dark energy components.Comment: 7 pages, 1 figure. Accepted for publication in the European Physical Journal