9,557 research outputs found
Quantum phase-space analysis of the pendular cavity
We perform a quantum mechanical analysis of the pendular cavity, using the
positive-P representation, showing that the quantum state of the moving mirror,
a macroscopic object, has noticeable effects on the dynamics. This system has
previously been proposed as a candidate for the quantum-limited measurement of
small displacements of the mirror due to radiation pressure, for the production
of states with entanglement between the mirror and the field, and even for
superposition states of the mirror. However, when we treat the oscillating
mirror quantum mechanically, we find that it always oscillates, has no
stationary steady-state, and exhibits uncertainties in position and momentum
which are typically larger than the mean values. This means that previous
linearised fluctuation analyses which have been used to predict these highly
quantum states are of limited use. We find that the achievable accuracy in
measurement is far worse than the standard quantum limit due to thermal noise,
which, for typical experimental parameters, is overwhelming even at 2 mK.Comment: 25 pages, 6 figures To be published in Phys. Rev.
Metodologia para determinação de ácido ascórbico em sucos de citrus utilizando cromatografia líquida de alta eficiência.
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A System for Aligning Geographical Entities from Large Heterogeneous Sources
Aligning points of interest (POIs) from heterogeneous geographical data sources is an important task that helps extend map data with information from different datasets. This task poses several challenges, including differences in type hierarchies, labels (different formats, languages, and levels of detail), and deviations in the coordinates. Scalability is another major issue, as global-scale datasets may have tens or hundreds of millions of entities. In this paper, we propose the GeographicaL Entities AligNment (GLEAN) system for efficiently matching large geographical datasets based on spatial partitioning with an adaptable margin. In particular, we introduce a text similarity measure based on the local-context relevance of tokens used in combination with sentence embeddings. We then come up with a scalable type embedding model. Finally, we demonstrate that our proposed system can efficiently handle the alignment of large datasets while improving the quality of alignments using the proposed entity similarity measure
Avaliação de resistência à Sigatoka-amarela em genótipos de bananeira.
A bananeira é produzida em cerca de 150 países em todos os continentes. Em 2011 a produção brasileira de banana chegou a 7.023.396 toneladas/ano, com aumento em relação aos anos anteriores. Entre os problemas fitossanitários da bananeira, a Sigatoka-amarela, causada por Mycosphaerella musicola Leach, é um dos mais importantes, haja vista a sua dispersão no país com adaptabilidade a diferentes condições climáticas e causa perdas estimadas em 50% na produção, com possibilidade de atingir 100% em alguns microclimas
Predicted defect induced vortex core switching in thin magnetic nanodisks
We investigate the influence of artificial defects (small holes) inserted
into magnetic nanodisks on the vortex core dynamics. One and two holes
(antidots) are considered. In general, the core falls into the hole but, in
particular, we would like to remark an interesting phenomenon not yet observed,
which is the vortex core switching induced by the vortex-hole interactions. It
occurs for the case with only one hole and for very special conditions
involving the hole size and position as well as the disk size. Any small
deformation in the disk geometry such as the presence of a second antidot
changes completely the vortex dynamics and the vortex core eventually falls
into one of the defects. After trapped, the vortex center still oscillates with
a very high frequency and small amplitude around the defect center.Comment: 11pages, Revtex format, 17 figure
Potencial genético de famílias de feijoeiro-comum obtidas por diferentes métodos de melhoramento.
O objetivo do trabalho foi comparar o potencial genético de famílias obtidas por diferentes métodos de melhoramento para teor de fibra bruta em feijoeiro-comum
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