12,929 research outputs found
Estimation of the Tropical Cyclone Diurnal Cycle Using Simulated Observations from the NASA TROPICS Earth Venture Mission
No abstract availabl
Assessing the identity of the variety "Pedro Giménez" grown in Argentina through the use of microsatellite markers.
'Pedro Giménez' es una variedad criolla blanca cultivada en Argentina, principalmente en las provincias de Mendoza y San Juan, siendo la variedad con la mayor superficie entre las uvas blancas de vinificación. Su origen es desconocido, como también su relación con la variedad española 'Pedro Ximénez', cultivada especialmente en la región de Jerez, España. En trabajos previos se ha probado que la mayoría de las variedades criollas existentes en América se habrían originado del cruzamiento de 'Moscatel de Alejandría' x 'Criolla Chica'. El presente trabajo tuvo como objetivos comparar las variedades 'Pedro Giménez' y 'Pedro Ximénez', y establecer relaciones de parentesco con 'Moscatel de Alejandría' y 'Criolla Chica'. Se utilizaron 18 loci microsatélites nucleares y 3 loci microsatélites de cloroplasto. 'Pedro Giménez' compartió sólo el 38% de los alelos con 'Pedro Ximénez', por lo que se pudo inferir que se trata de variedades diferentes. En todos los loci polimórficos nucleares analizados 'Pedro Giménez' compartió uno de los alelos con 'Moscatel de Alejandría' y el otro con 'Criolla Chica'. Estos datos, junto con el resultado del análisis de SSR de cloroplastos, avalan la hipótesis que, como muchas de las variedades criollas, 'Pedro Giménez' sería fruto del cruzamiento entre estos dos progenitores, siendo 'Criolla Chica' probablemente el progenitor materno.´Pedro Giménez´ is a white criolla variety cropped in Argentina, mainly in Mendoza and San Juan, being the most planted white variety destined for wine making in the country. Its origin remains unknown, as well as its relationship with Spanish variety ´Pedro Ximénez´, mostly grown in Jerez, Spain. Previous works have probed that most of Criollas varieties existing in America at the moment, are the offspring of ´Muscat of Alexandria´ x ´Criolla Chica´. The aim of the present work was to compare ´Pedro Giménez´ with the Spanish variety ´Pedro Ximénez´, and to establish its degree of relatedness to ´Muscat of Alexandria´ and ´Criolla Chica´. Therefore we used a set of 18 nuclear SSR loci and 3 chloroplast SSR loci. ´Pedro Giménez´ shared only 38% of the alleles under analysis with ´Pedro Ximénez´, indicating that they are indeed two different varieties. In all 18 polymorphic nuclear SSR loci ´Pedro Giménez´ shared 50% of its alleles with ´Muscat of Alexandria´, while the other 50% of the alleles present in ´Pedro Giménez´ were also present in ´Criolla Chica´. This data, along with those from the chloroplast SSR analysis, strongly suggest that ´Pedro Giménez´ is the progeny of ´Muscat of Alexandria´ x ´Criolla Chica´, being the latest one the most likely female progenitor.Fil: Duran, Martin Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Biología Agrícola de Mendoza. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Instituto de Biología Agrícola de Mendoza; ArgentinaFil: Agüero, Cecilia B.. University of California at Davis; Estados UnidosFil: Martínez, Liliana Estela. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Ciencias Biológicas. Cátedra de Fisiología Vegetal; Argentin
Fast Hierarchical Clustering and Other Applications of Dynamic Closest Pairs
We develop data structures for dynamic closest pair problems with arbitrary
distance functions, that do not necessarily come from any geometric structure
on the objects. Based on a technique previously used by the author for
Euclidean closest pairs, we show how to insert and delete objects from an
n-object set, maintaining the closest pair, in O(n log^2 n) time per update and
O(n) space. With quadratic space, we can instead use a quadtree-like structure
to achieve an optimal time bound, O(n) per update. We apply these data
structures to hierarchical clustering, greedy matching, and TSP heuristics, and
discuss other potential applications in machine learning, Groebner bases, and
local improvement algorithms for partition and placement problems. Experiments
show our new methods to be faster in practice than previously used heuristics.Comment: 20 pages, 9 figures. A preliminary version of this paper appeared at
the 9th ACM-SIAM Symp. on Discrete Algorithms, San Francisco, 1998, pp.
619-628. For source code and experimental results, see
http://www.ics.uci.edu/~eppstein/projects/pairs
Diffusion of a granular pulse in a rotating drum
The diffusion of a pulse of small grains in an horizontal rotating drum is
studied through discrete elements methods simulations. We present a theoretical
analysis of the diffusion process in a one-dimensional confined space in order
to elucidate the effect of the confining end-plate of the drum. We then show
that the diffusion is neither subdiffusive nor superdiffusive but normal. This
is demonstrated by rescaling the concentration profiles obtained at various
stages and by studying the time evolution of the mean squared deviation.
Finally we study the self-diffusion of both large and small grains and we show
that it is normal and that the diffusion coefficient is independent of the
grain size
A Lightweight Regression Method to Infer Psycholinguistic Properties for Brazilian Portuguese
Psycholinguistic properties of words have been used in various approaches to
Natural Language Processing tasks, such as text simplification and readability
assessment. Most of these properties are subjective, involving costly and
time-consuming surveys to be gathered. Recent approaches use the limited
datasets of psycholinguistic properties to extend them automatically to large
lexicons. However, some of the resources used by such approaches are not
available to most languages. This study presents a method to infer
psycholinguistic properties for Brazilian Portuguese (BP) using regressors
built with a light set of features usually available for less resourced
languages: word length, frequency lists, lexical databases composed of school
dictionaries and word embedding models. The correlations between the properties
inferred are close to those obtained by related works. The resulting resource
contains 26,874 words in BP annotated with concreteness, age of acquisition,
imageability and subjective frequency.Comment: Paper accepted for TSD201
Fluctuation-Induced Casimir Forces in Granular Fluids
We have numerically investigated the behavior of driven non-cohesive granular
media and found that two fixed large intruder particles, immersed in a sea of
small particles, experience, in addition to a short range depletion force, a
long range repulsive force. The observed long range interaction is
fluctuation-induced and we propose a mechanism similar to the Casimir effect
that generates it: the hydrodynamic fluctuations are geometrically confined
between the intruders, producing an unbalanced renormalized pressure. An
estimation based on computing the possible Fourier modes explains the repulsive
force and is in qualitative agreement with the simulations.Comment: 4 pages, 3 figures. Accepted in Phys. Rev. Letter
Nitrous oxide in fresh water systems: An estimate for the yield of atmospheric N2O associated with disposal of human waste
The N2O content of waters in the Potomac and Merrimack Rivers was measured on a number of occasions over the period April to July 1977. The concentrations of dissolved N2O exceeded those which would apply in equilibrium with air by factors ranging from about 46 in the Potomac to 1.2 in the Merrimack. Highest concentrations of dissolved N2O were associated with sewage discharges from the vicinity of Washington, D. C., and analysis indicates a relatively high yield, 1.3 to 11%, for prompt conversion of waste nitrogen to N2O. Measurements of dissolved N2O in fresh water ponds near Boston demonstrated that aquatic systems provide both strong sources and sinks for atmospheric N2O
Size segregation and convection
The size segregation of granular materials in a vibrating container is
investigated using Molecular Dynamics. We find that the rising of larger
particles is accompanied by the existence of convection cells even in the case
of the lowest possible frequencies. The convection can, however, also be
triggered by the larger particle itself. The possibility of rising through this
mechanism strongly depends on the depth of the larger particle.Comment: 7 pages, 4 figure
Wall effects on granular heap stability
We investigate the effects of lateral walls on the angle of movement and on
the angle of repose of a granular pile. Our experimental results for beads
immersed in water are similar to previous results obtained in air and to recent
numerical simulations. All of these results, showing an increase of pile angles
with a decreasing gap width, are explained by a model based on the redirection
of stresses through the granular media. Two regimes are observed depending on
the bead diameter. For large beads, the range of wall effects corresponds to a
constant number of beads whereas it corresponds to a constant characteristic
length for small beads as they aggregate via van der Waals forces
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