1,351 research outputs found
Simple approach to the mesoscopic open electron resonator: Quantum current oscillations
The open electron resonator, described by Duncan et.al, is a mesoscopic
device that has attracted considerable attention due to its remarkable
behaviour (conductance oscillations), which has been explained by detailed
theories based on the behaviour of electrons at the top of the Fermi sea. In
this work, we study the resonator using the simple quantum quantum electrical
circuit approach, developed recently by Li and Chen. With this approach, and
considering a very simple capacitor-like model of the system, we are able to
theoretically reproduce the observed conductance oscillations. A very
remarkable feature of the simple theory developed here is the fact that the
predictions depend mostly on very general facts, namely, the discrete nature of
electric charge and quantum mechanics; other detailed features of the systems
described enter as parameters of the system, such as capacities and
inductances
Molecular and Genetic Regulation of Sensory Quality of Climacteric Fruit
The sensory quality of fruit has become a major criterion in making the
purchasing decision by consumers. Breeding programs have mainly been directed,
from the post-harvest stand point, towards improving shelf-life. Chance seedlings or
mutants with improved agronomic traits and/or extended shelf-life have been used
for introgressing the long shelf-life character and eventually improved sensory
quality traits in commercial genotypes of apple, melon or tomato. Because the plant
hormone ethylene plays a central role in both storability and ripening of climacteric
fruit, the generation by biotechnology of ethylene-inhibited fruit has offered a
powerful tool to better understand, at the molecular and genetic level, the interrelations
between storability and sensory quality. In the melon, inhibition of ethylene
synthesis results is a strong inhibition of the synthesis of aroma volatiles while the
accumulation of sugars is not affected or is even improved. The softening of the flesh
is strongly affected but not abolished. Mid or long shelf-life melons generated by
classical breeding present the same behavior. The generation of recombinant inbred
lines by crossing a typical climacteric melon (Cantaloupe Charentais of the
cantalupensis group) with a non climacteric melon (PI161375 of the agrestis
chinensis group) allowed to demonstrate that the climacteric character is conferred
by 2 duplicated loci only, which are of great importance for the regulation of
storability and sensory quality. Due to the importance of aroma volatiles in sensory
quality and to the strong negative correlation between aroma production and
ethylene synthesis, we have developed a research program aimed at isolating genes
involved in the synthesis of aroma volatiles. We will report on the recent advances in
the field with special emphasis on the characterization of genes responsible for the
synthesis of esters, a family of compounds crucial for the flavor of many fruit
Los Evangelizadores: Obispos, Sacerdotes, Diáconos, Religiosos, Religiosas, Laicos. IV Reunión Plenaria.Vaticano 19-23 de Junio de 1995 (Reseña)
Reseña del libro de la PONTIFICIA COMISIÓN PARA AMÉRICA LATINA, Los Evangelizadores: Obispos, Sacerdotes, Diáconos, Religiosos, Religiosas, Laicos. IV Reunión Plenaria. Vaticano 19-23 de Junio de 1995, Librería Editrice Vaticana, Ciudad del Vaticano 1996, 230 pp
Los dominicos y el Nuevo Mundo: Siglos XVIII y XIX, Actas del IV Congreso Internacional Santafé de Bogotá (Reseña)
Reseña del libro de José BARRADO BARQUILLA (ed.), Los dominicos y el Nuevo Mundo: Siglos XVIII y XIX, Actas del IV Congreso Internacional Santafé de Bogotá, San Esteban, Salamanca 1995, 643 pp
Intrinsic decoherence and classical-quantum correspondence in two coupled delta-kicked rotors
We show that classical-quantum correspondence of center of mass motion in two
coupled delta-kicked rotors can be obtained from intrinsic decoherence of the
system itself which occurs due to the entanglement of the center of mass motion
to the internal degree of freedom without coupling to external environment
Climacteric fruit ripening: Ethylene-dependent and independent regulation of ripening pathways in melon fruit
Cantaloupe melons have a typical climacteric behaviour with ethylene playing a major role in the regulation of the ripening process and
affecting the ripening rate. Crossing of Cantaloupe Charentais melon with a non-climacteric melon indicated that the climacteric character is
genetically dominant and conferred by two duplicated loci only. However, other experiments made by crossing two non-climacteric melons
have generated climacteric fruit, indicating that different and complex genetic regulation exists for the climacteric character. Suppression of
ethylene production by antisense ACC oxidase RNA in Charentais melon has shown that, while many ripening pathways were regulated by
ethylene (synthesis of aroma volatiles, respiratory climacteric and degreening of the rind), some were ethylene-independent (initiation of
climacteric, sugar accumulation, loss of acidity and coloration of the pulp). Softening of the flesh comprised both ethylene-dependent and
independent components that were correlated with differential regulation of cell wall degrading genes. These results indicate that climacteric
(ethylene-dependent) and non-climacteric (ethylene-independent) regulation coexist during climacteric fruit ripening. In addition, ethylenesuppressed
melons allowed demonstrating that the various ethylene-dependent events exhibited differential sensitivity to ethylene and that
ethylene was promoting sensitivity to chilling injury. Throughout this review, the data generated with melon are compared with those
obtained with tomato and other fruit
EP-1270: Volumetric modulated arc therapy in high-risk neuroblatoma¥s treatment. Single institucional experience
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