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

CO observations and investigation of triggered star formation towards N10 infrared bubble and surroundings

We studied the environment of the dust bubble N10 in molecular emission. Infrared bubbles, first detected by the GLIMPSE survey at 8.0 $\mu$m, are ideal regions to investigate the effect of the expansion of the HII region on its surroundings eventual triggered star formation at its borders. In this work, we present a multi-wavelength study of N10. This bubble is especially interesting as infrared studies of the young stellar content suggest a scenario of ongoing star formation, possibly triggered, on the edge of the HII region. We carried out observations of $^{12}$CO(1-0) and $^{13}$CO(1-0) emission at PMO 13.7-m towards N10. We also analyzed the IR and sub-mm emission on this region and compare those different tracers to obtain a detailed view of the interaction between the expanding HII region and the molecular gas. We also estimated the parameters of the denser cold dust condensation and of the ionized gas inside the shell. Bright CO emission was detected and two molecular clumps were identified, from which we have derived physical parameters. We also estimate the parameters for the densest cold dust condensation and for the ionized gas inside the shell. The comparison between the dynamical age of this region and the fragmentation time scale favors the "Radiation-Driven Implosion" mechanism of star formation. N10 reveals to be specially interesting case with gas structures in a narrow frontier between HII region and surrounding molecular material, and with a range of ages of YSOs situated in region indicating triggered star formation.Comment: Version 2 - Submmited to ApJ (under review

Allegacion en derecho, en fauor de Don Yñigo de Mendoça y de la Cerda, en el pleyto, que tratta con la Princesa de Ebuli, y Duque de Pastrana, su hijo, sobre los mayorazgos, que hizieron, y fundaron, el Cardenal Don Pero Gonçales de Mendoça, y Don Diego d

A 109/157(10

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