5,167 research outputs found
Primeiro registro de nematoide de cisto da soja na Região Centro-Sul de Mato Grosso do Sul.
O nematoide de cisto da soja (NCS), Heterodera glycines, é um dos principais fatores limitantes à produção de soja no Brasil. Desde a sua constatação na safra 1991/1992, o NCS distribuiu-se por praticamente todas as regiões produtoras de soja do PaÃs, estando presente atualmente em cerca de 2 milhões de hectares nos seguintes estados: Rio Grande do Sul, Paraná, São Paulo, Mato Grosso do Sul, Mato Grosso, Minas Gerais, Goiás, Tocantins, Maranhão e Bahia (EMBRAPA, 2009). Em Mato Grosso do Sul, o NCS permaneceu limitado à s regiões Norte e Nordeste do estado, onde causa perdas consideráveis.bitstream/item/51822/1/COT-2011-170.pd
The unstructured Scaldis model: a new 3D high resolution model for hydrodynamics and sediment transport in the tidal Scheldt
In the framework of the projects "Integral Plan for the Upper Sea Scheldt" and "Agenda for the Future", the SCALDIS model, a new unstructured high resolution model of the tidal Scheldt is developed in TELEMAC 3D (Telemac-Mascaret software platform). Starting from the stated model purpose, a weighted dimensionless cost function is set up that attributes equal weight to the vertical and the horizontal tide. By adapting the bottom roughness, the cost function is minimized during model calibration. Quantification of the model skill and cost function calculation is done using the VIMM toolbox which is developed and maintained at Flanders Hydraulics Research. The quantified model skill of the SCALDIS model shows that the model is well suited to assess the effects of changing the bathymetry and geometry of the Scheldt river on water levels, velocities, tracer dispersion and residence times, and that the hydrodynamics can be used as the basis for sediment transport calculations (both cohesive and non-cohesive)
Numerical modelling of flood control areas with controlled reduced tide
The present paper focuses on the numerical modelling in TELEMAC-3D of flood control areas with controlled reduced tide structures along the Scheldt estuary and coastal zone for the storm event of December 6th, 2013. A new culvert functionality was implemented in the code to better represent the hydrodynamics of the exchange of water between the Scheldt estuary and these flood control areas with controlled reduced tide. Existing source and sink terms included in the code were paired and used as a culvert. The theoretical background to represent the different kind of flows through the culvert was based on the work of Bodhaine (1968). Additionally different head loss coefficients were introduced according to different geometric features of the culverts. The implementation of these new structures inside the 3D numerical model was validated using measured water levels in the estuary and inside the flooding areas , and using discharges (in and out) through the culverts measured only for one full tidal cycle. For the storm surge only measured water levels were available and these were compared with modelled ones
Normalization procedure for relaxation studies in NMR quantum information processing
NMR quantum information processing studies rely on the reconstruction of the
density matrix representing the so-called pseudo-pure states (PPS). An
initially pure part of a PPS state undergoes unitary and non-unitary
(relaxation) transformations during a computation process, causing a "loss of
purity" until the equilibrium is reached. Besides, upon relaxation, the nuclear
polarization varies in time, a fact which must be taken into account when
comparing density matrices at different instants. Attempting to use time-fixed
normalization procedures when relaxation is present, leads to various anomalies
on matrices populations. On this paper we propose a method which takes into
account the time-dependence of the normalization factor. From a generic form
for the deviation density matrix an expression for the relaxing initial pure
state is deduced. The method is exemplified with an experiment of relaxation of
the concurrence of a pseudo-entangled state, which exhibits the phenomenon of
sudden death, and the relaxation of the Wigner function of a pseudo-cat state.Comment: 9 pages, 5 figures, to appear in QI
Block-windowed burst OFDM: A high-efficiency multicarrier technique
A block-windowed burst orthogonal frequency division multiplexing (OFDM) technique which is a multicarrier technique with power spectral density similar to the filtered OFDM approach, since it also employs smoother, non-rectangular windows, is presented. However, it does not need a cyclic prefix, which means the overall power and spectral efficiencies are higher. An appropriate receiver for typical time-dispersive channels, allowing 2 dB of gain relatively conventional OFDM schemes is also presented
Quantum state tomography and quantum logical operations in a three qubits NMR quadrupolar system
In this work, we present an implementation of quantum logic gates and
algorithms in a three effective qubits system, represented by a (I = 7/2) NMR
quadrupolar nuclei. To implement these protocols we have used the strong
modulating pulses (SMP). The various stages of each implementation were
verified by quantum state tomography (QST). It is presented here the results
for the computational base states, Toffolli logic gates, and Deutsch-Jozsa and
Grover algorithms. Also, we discuss the difficulties and advantages of
implementing such protocols using the SMP technique in quadrupolar systems.Comment: 24 pages, 8 figure
Statistical Mechanics of Unbound Two Dimensional Self-Gravitating Systems
We study, using both theory and molecular dynamics simulations, the
relaxation dynamics of a microcanonical two dimensional self-gravitating
system. After a sufficiently large time, a gravitational cluster of N particles
relaxes to the Maxwell-Boltzmann distribution. The time to reach the
thermodynamic equilibrium, however, scales with the number of particles. In the
thermodynamic limit, at fixed total mass, equilibrium state is
never reached and the system becomes trapped in a non-ergodic stationary state.
An analytical theory is presented which allows us to quantitatively described
this final stationary state, without any adjustable parameters
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