Ethanol Vapours to Complement or Replace Sulfur Dioxide Fumigation of Table Grapes

Recent studies have shown that dipping table grapes in ethanol solutions at harvest improved storage of the fruit. We report here the first results obtained by treating "Chasselas" table grapes (Vitis vinifera) with ethanol vapours over the storage period. We tested the effect of ethanol at 0, 4 and 8 g/kg fruit during cold storage for 2, 4 and 6 weeks. We measured berry shatter, stem browning, Botrytis rot incidence and sensory appreciation by tasting panels. Ethanol vapours reduced Botrytis rot incidence and berry shatter, but hastened stem browning. Sensory analyses did not detect any differences between treatments

Cariotipo de Espeletiopsis muiska

RESUMEN Objetivo. Estudiar el ciclo celular y realizar la descripción cromosómica de Espeletiopsis muiska, utilizando células meristemáticas de ápices radicales obtenidos a través de cultivo in vitro de embriones en medio MS suplementado con AIB. Materiales y métodos. Se colectaron ápices radicales a diferentes horas del día y se contaron en ellos las células presentes en cada fase mitótica, se determinó la duración del ciclo celular y la hora de mayor actividad mitótica. La descripción de los cromosomas y la elaboración del cariotipo de la especie, se realizó utilizando un protocolo que permitió la obtención de cromosomas metafásicos. Resultados. Respecto a la duración del ciclo celular, se encontró que la interfase comprende el 94.65% y la mitosis el 5.35% del total del ciclo celular. Entre las fases mitóticas la profase tiene mayor duración, 1.92%, mientras que la anafase es la más corta, 0.96%. En cuanto a la hora mitótica, las células meristemáticas de los ápices radicales presentaron mayor actividad entre las 10:30 y las 11:15. Con el estudio citogenético se encontraron 19 pares de cromosomas con longitudes e índices centroméricos similares y cariotipo asimétrico. Conclusiones. El estudio detallado de los cromosomas, permitió determinar un complemento cromosómico 2n=38+2B, dos cromosomas con microsatélites terminales y uno con constricción secundaria

Cariotipo de Espeletiopsis muiska

Objective. The cell cycle and chromosomic description of Espeletiopsis muiska was studied in meristematic cells of root tips obtained from in vitro culture of embryos on MS medium supplemented with IBA. Materials and methods. Root tips at different times of day were collected and the cells in each mitotic phase were counted. With this information, the cell cycle length and mitotic activity was determined at its peak hours. Description of chromosomes and elaboration of karyotype of the specie was done with a protocol that allows obtaining metaphase chromosomes. Results. Regarding the cell cycle length, we found that the interface includes the 94.65% and mitosis the 5.35% of total cell cycle. Regarding the mitotic phases, the prophase lasts longer, 1.92%, while the anaphase is the shortest, 0.96%. As to mitotic hour, meristematic cells of root tips showed an increased activity between 10:30 and 11:15. 19 pairs of chromosomes with similar lengths, similar centromeric indices and asymmetrical karyotype were found in this cytogenetic study. Conclusions. The detailed study of the chromosomes revealed a chromosome complement 2n=38+2B, two chromosomes with microsatellite terminals and one with a secondary constriction.Objetivo. Estudiar el ciclo celular y realizar la descripción cromosómica de Espeletiopsis muiska, utilizando células meristemáticas de ápices radicales obtenidos a través de cultivo in vitro de embriones en medio MS suplementado con AIB. Materiales y métodos. Se colectaron ápices radicales a diferentes horas del día y se contaron en ellos las células presentes en cada fase mitótica, se determinó la duración del ciclo celular y la hora de mayor actividad mitótica. La descripción de los cromosomas y la elaboración del cariotipo de la especie, se realizó utilizando un protocolo que permitió la obtención de cromosomas metafásicos. Resultados. Respecto a la duración del ciclo celular, se encontró que la interfase comprende el 94.65% y la mitosis el 5.35% del total del ciclo celular. Entre las fases mitóticas la profase tiene mayor duración, 1.92%, mientras que la anafase es la más corta, 0.96%. En cuanto a la hora mitótica, las células meristemáticas de los ápices radicales presentaron mayor actividad entre las 10:30 y las 11:15. Con el estudio citogenético se encontraron 19 pares de cromosomas con longitudes e índices centroméricos similares y cariotipo asimétrico. Conclusiones. El estudio detallado de los cromosomas, permitió determinar un complemento cromosómico 2n=38+2B, dos cromosomas con microsatélites terminales y uno con constricción secundaria

Ripple rotation in epitaxial growth of MnAs(1(1)over-bar00)

International audienceRippled states formation driven by kinetic instability is evidenced in the case of MnAs(1 (1) over bar 00) hetero- and homoepitaxial growth in a narrow multistable range of growth parameters. The evolution of the surface morphology in this range, comprising slope selection and ripple rotation, maps the kinetic phase diagram recently predicted [A. Levandovsky and L. Golubovic, Phys. Rev. E 76, 041605 (2007)] for growth on rectangular symmetry surfaces, including Ehrlich-Schwoebel instability and effects related to vertical asymmetry

Hexagon-on-cube versus cube-on-cube epitaxy: The case of ZnSe(111) on SrTiO3(001)

International audienceThe structure of ZnSe epilayers grown by molecular-beam epitaxy on SrTiO3 001 substrates has been studied using electron diffraction, x-ray diffraction, and electron microscopy. ZnSe, like certain other zincblende semiconductors, grows epitaxially along the 111 direction, contrary to what is expected from considerations on lattice registry and mismatch. First-principles calculations based on density-functional theory show that this peculiar epitaxy results from the subtle balance between strain and interface bonding during the growth of the first layer

Unforeseen properties of MnAs epilayers grown on GaAs semiconductor

4th Workshop on At the Frontiers of Condensed Matter, Buenos Aires, ARGENTINA, DEC 09-12, 2008International audienceThis paper reviews some recent works performed on MnAs/GaAs thin films and other related structures grown by molecular beam epitaxy. The impact of epitaxy on the magneto-structural properties of MnAs and possible applications of MnAs epilayers are discussed. A brief account of recent results obtained on the magneto-trans port in MnAs/GaAs/MnAs magnetic tunnel junctions is also given, highlighting several appealing and promising properties of this system for spintronics applications. (C) 2009 Elsevier B.V. All rights reserved

Metastable tetragonal structure of Fe100-xGax epitaxial thin films on ZnSe/GaAs(001) substrate

International audienceWe investigated by x-ray diffraction the Ga concentration dependences of the structural properties of Fe100-xGax (galfenol) thin films grown on a ZnSe/GaAs(001) substrate, a material known for its high magnetostriction. By molecular beam epitaxy (MBE) we grew a series of (001)-oriented layers without in-plane misorientation, ranging from pure Fe up to x = 29.4% Ga. We find a strong Ga-induced tetragonal distortion that conserves the pristine Fe in-plane lattice parameters for all Ga compositions. Supported by theoretical predictions [R. Wu, J. Appl. Phys. 91, 7358 (2002)], we attribute this unusual tetragonal distortion to short-range ordering of Ga-Ga pairs along the [001]-growth direction. The low-temperature and out-of-equilibrium MBE growth regime tends to stabilize a strong deformed tetragonal phase (up to c/a similar to 1.05 for x similar to 29%). This tetragonal structure is fully released by postgrowth annealing