579 research outputs found
Factors affecting rind pitting in the mandarin hybrids "fortune" and "nova". The influence of exogenous growth regulators
The commercialization of the mandarin hybrids "Fortune" and "Nova" is hindered by the development of cold-induced pitting in the fruit rind which may develop either in the orchard or during storage and transport.
In the late cropping cultivar "Fortune", the pitting develops on tree during the winter months and affects mainly the exposed fruit from the north-west quadrant of the tree. The induction of symptoms under uniform conditions in the cold-room reveals differences in the susceptibility to chilling injury among the fruits and the fruit sides. The green fruit is not susceptible. Susceptibility develops as pigmentation progresses, and it is higher for the exposed than for the non-exposed (covered by the foliage) fruits. The application of GA3 at colour-break delays pigmentation and retards the development of susceptibility. The waxing of the fruit offers some protection to cold in the cold-room. However, the incidence of pitting is not related to the wax content of the fruit rind and the application of a wax coverage on tree had only a marginal protective effect.
No pitting is usually found on tree in the fruit of the early ripening "Nova" cultivar, which is usually harvested before the winter chilling. The pitting develops during cold storage (8-10 C), and is reduced by GA3 application at colour break, an effect related to the delay in rind pigmentation.info:eu-repo/semantics/publishedVersio
Two-dimensional molecular para-hydrogen and ortho-deuterium at zero temperature
We study molecular para-hydrogen (p-) and ortho-deuterium
(o-) in two dimensions and in the limit of zero temperature by
means of the diffusion Monte Carlo method. We report energetic and structural
properties of both systems like the total and kinetic energy per particle,
radial pair distribution function, and Lindemann's ratio in the low pressure
regime. By comparing the total energy per particle as a function of the density
in liquid and solid p-, we show that molecular para-hydrogen, and
also ortho-deuterium, remain solid at zero temperature. Interestingly, we
assess the quality of three different symmetrized trial wave functions, based
on the Nosanow-Jastrow model, in the p- solid film at the
variational level. In particular, we analyze a new type of symmetrized trial
wave function which has been used very recently to describe solid He and
found that also characterizes hydrogen satisfactorily. With this wave function,
we show that the one-body density matrix of solid p- possesses off-diagonal long range order, with a condensate fraction
that increases sizably in the negative pressure regime.Comment: 11 pages, 9 figure
Equation of state of low--density neutron matter and the pairing gap
We report results of the equation of state of neutron matter in the
low--density regime, where the Fermi wave vector ranges from . Neutron matter in this regime is superfluid because of
the strong and attractive interaction in the channel. The properties of
this superfluid matter are calculated starting from a realistic Hamiltonian
that contains modern two-- and three--body interactions. The ground state
energy and the superfluid energy gap are calculated using the Auxiliary
Field Diffusion Monte Carlo method. We study the structure of the ground state
by looking at pair distribution functions as well as the Cooper-pair wave
function used in the calculations.Comment: 12 pages, 7 figure
Solidification of small para-H2 clusters at zero temperature
We have determined the ground-state energies of para-H clusters at zero
temperature using the diffusion Monte Carlo method. The liquid or solid
character of each cluster is investigated by restricting the phase through the
use of proper importance sampling. Our results show inhomogeneous
crystallization of clusters, with alternating behavior between liquid and solid
phases up to N=55. From there on, all clusters are solid. The ground-state
energies in the range N=13--75 are established and the stable phase of each
cluster is determined. In spite of the small differences observed between the
energy of liquid and solid clusters, the corresponding density profiles are
significantly different, feature that can help to solve ambiguities in the
determination of the specific phase of H clusters.Comment: 17 pages, accepted for publication in J. Phys. Chem.
Atomic kinetic energy, momentum distribution and structure of solid neon at zero-temperature
We report on the calculation of the ground-state atomic kinetic energy,
, and momentum distribution of solid Ne by means of the diffusion Monte
Carlo method and Aziz HFD-B pair potential. This approach is shown to perform
notably for this crystal since we obtain very good agreement with respect to
experimental thermodynamic data. Additionally, we study the structural
properties of solid Ne at densities near the equilibrium by estimating the
radial pair-distribution function, Lindemann's ratio and atomic density profile
around the positions of the perfect crystalline lattice. Our value for
at the equilibrium density is K, which agrees perfectly with the
recent prediction made by Timms {\it et al.}, K, based on their
deep-inelastic neutron scattering experiments carried out over the temperature
range K, and also with previous path integral Monte Carlo results
obtained with the Lennard-Jones and Aziz HFD-C2 atomic pairwise interactions.
The one-body density function of solid Ne is calculated accurately and found to
fit perfectly, within statistical uncertainty, to a Gaussian curve.
Furthermore, we analyze the degree of anharmonicity of solid Ne by calculating
some of its microscopic ground-state properties within traditional harmonic
approaches. We provide insightful comparison to solid He in terms of the
Debye model, in order to size the relevance of anharmonic effects in Ne.Comment: 20 pages, 7 figures. To be published in Physical Review
Los suelos de la provincia de Granada y su posible incidencia en la fertilidad del olivo: II. Suelos pardo calizos
Se estudian suelos de olivar que presentan un horizonte B de propiedades y morfología muy variadas. El comportamiento frente al olivo está relacionado con dicho horizonte B y la presencia en algunos casos de un horizonte cálcico. Estos caracteres y el clima son los factores, independientemente del humano, responsables de la fertilidad del olivar desarrollados sobre ellos.At the present paper it has been studied 14 soils profiles under olive
trees which present a B horizon with properties and morphology very
different.
The relation-ships between the culture of the olive-trees and the B hor1-
zon are very straight so as in sorne cases the presence of a calcic horizon.
These characters and the climatology, besides the human factor, are
the factors responsibles of the fertility of the olive-trees developed on
these soils
Los suelos de la provincia de Granada y su posible influencia en la fertilidad del olivo. III. Suelos pardos rojos calizos y tierras pardas
Se estudian algunos suelos pardos rojizos y tierras pardas meridionales de la provincia de Granada, dedicadas al cultivo del olivo, detallando la posible correlación existente entre suelo y planta.It have been studied some brown-reddish soils and meridional brown
soils of the Granade provínce which are dedicated to the culture of the
olive-trees and we have pointed out about the possible correlation between
soil and plant
Los suelos de la provincia de Granada y su posible incidencia en la fertilidad del olivo. I. – Suelos rendsiniformes y vertisoles
Se agrupan en el presente trabajo, primero de una serie de cuatro, dedicado al estudio de los suelos con olivar en la provincia de Granada, a aquellos suelos con perfil poco desarrollaDo, que pueden ser clasificados como suelos rendsiniformes. vertisuelos y sus integrados. Se pone de manifiesto la complejidad y ambigüedad de los términos utilizados en algunas de las clasificaciones más usuales y se toma la de la FAO como clasificación de referencia. La relación suelo fertilidad, según les perfiles estudiados es la siguiente:
Regosoles → Vertisoles → Serosoles → Yermosoles
Los factores ,condicionantes son el espesor del suelo, la presencia de costra yesosa más o menos superficial, hidromorfia y climatología de la zona.We have studied at the present papel" four types of soils with very
litle developed pro fiJe s which may be classified as Rendsina soils, VertisoIs and their integrades.
The relation soil/fertility according to the soils studied is as fallaws:
Regosols → Vertisols → Xerosols → ·ermosols
The main factors which influence the soil fertility are: soils depth,
the presence of gypsum cousts more or less near surface, hidromorphic
conditions and the climatologie of the zone
Spiked oscillators: exact solution
A procedure to obtain the eigenenergies and eigenfunctions of a quantum
spiked oscillator is presented. The originality of the method lies in an
adequate use of asymptotic expansions of Wronskians of algebraic solutions of
the Schroedinger equation. The procedure is applied to three familiar examples
of spiked oscillators
Bifurcation Diagram for Compartmentalized Granular Gases
The bifurcation diagram for a vibro-fluidized granular gas in N connected
compartments is constructed and discussed. At vigorous driving, the uniform
distribution (in which the gas is equi-partitioned over the compartments) is
stable. But when the driving intensity is decreased this uniform distribution
becomes unstable and gives way to a clustered state. For the simplest case,
N=2, this transition takes place via a pitchfork bifurcation but for all N>2
the transition involves saddle-node bifurcations. The associated hysteresis
becomes more and more pronounced for growing N. In the bifurcation diagram,
apart from the uniform and the one-peaked distributions, also a number of
multi-peaked solutions occur. These are transient states. Their physical
relevance is discussed in the context of a stability analysis.Comment: Phys. Rev. E, in press. Figure quality has been reduced in order to
decrease file-siz
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