16,932 research outputs found
Valor nutritivo do mata-pasto (Senna obtusifolia (L.) Irwin & Barneby) em diferentes idades.
O mata-pasto (Senna obtusifolia (L.) Irwin & Barneby), leguminosa de larga ocorrência natural no Nordeste, apesar de não apreciada pelos ruminantes quando verde, é muito consumida quando naturalmente seca. Apresenta, portanto, a possibilidade de ser usada como feno, para diminuir a carência alimentar da época seca. Este trabalho teve como objetivo a determinação dos percentuais de proteína bruta (PB), fibra bruta (FB), extrato etéreo IEE), cálcio (Ca) e fósforo (P), na planta inteira, caule e folhas do mata-pasto, em diferentes idades. Coletaram-se, mensalmente, dos 30 aos 180 dias de idade, cinco amostras de 0,5 x 0,5 m para a análise da planta inteira e outras cinco para caules e folhas. A PB diminuiu com a idade das plantas, sendo maior nas folhas (11,75% - 28,63%) e menor nos caules (2,44% - 22,46%). A FB foi maior nos caules (29,50% - 48,50%) do que nas folhas (8,28% - 10,52%), aumentando com a idade. O EE pouco variou em relação às partes da planta, como tambem com a idade (2,91% - 3,34% nas folhas e 0,83% - 1,04% nos caules). O P decresceu com a idade, sendo de 0,16% - 0,28% nas folhas e 0,11% - 0,20% nos caules. O Ca foi também mais alto nas folhas (1,33% - 3,07%), onde aumentou com a idade, enquanto decresceu nos caules e na planta inteira. Todas as variáveis tiveram, na planta inteira, valores intermediários entre os observados nas folhas e nos caules. O mata-pasto é uma planta nutricionalmente adequada, com seu corte para fenação por volta de 120 dias.bitstream/item/35799/1/BP33.pd
Sub-gap optical response across the structural phase transition in van der Waals layered \alpha-RuCl
We report magnetic, thermodynamic, thermal expansion, and on detailed optical
experiments on the layered compound -RuCl focusing on the THz and
sub-gap optical response across the structural phase transition from the
monoclinic high-temperature to the rhombohedral low-temperature structure,
where the stacking sequence of the molecular layers is changed. This type of
phase transition is characteristic for a variety of tri-halides crystallizing
in a layered honeycomb-type structure and so far is unique, as the
low-temperature phase exhibits the higher symmetry. One motivation is to
unravel the microscopic nature of spin-orbital excitations via a study of
temperature and symmetry-induced changes. We document a number of highly
unusual findings: A characteristic two-step hysteresis of the structural phase
transition, accompanied by a dramatic change of the reflectivity. An electronic
excitation, which appears in a narrow temperature range just across the
structural phase transition, and a complex dielectric loss spectrum in the THz
regime, which could indicate remnants of Kitaev physics. Despite significant
symmetry changes across the monoclinic to rhombohedral phase transition, phonon
eigenfrequencies and the majority of spin-orbital excitations are not strongly
influenced. Obviously, the symmetry of the single molecular layers determine
the eigenfrequencies of most of these excitations. Finally, from this combined
terahertz, far- and mid-infrared study we try to shed some light on the so far
unsolved low energy (< 1eV) electronic structure of the ruthenium
electrons in -RuCl.Comment: 22 pages, 9 figure
Quick Models for Saccade Amplitude Prediction
This paper presents a new saccade amplitude prediction model. The model is based on a Kalman filter and regression analysis. The aim of the model is to predict a saccade’s am-plitude extremely quickly, i.e., within two eye position samples at the onset of a saccade. Specifically, the paper explores saccade amplitude prediction considering one or two sam-ples at the onset of a saccade. The models’ prediction performance was tested with 35 subjects. The amplitude accuracy results yielded approximately 5.26° prediction error, while the error for direction prediction was 5.3% for the first sample model and 1.5% for the two samples model. The practical use of the proposed model lays in the area of real-time gaze-contingent compression and extreme eye-gaze aware interaction applications. The paper provides theoretical evaluation of the benefits of saccade amplitude prediction to the gaze-contingent multimedia compression, estimating a 21% improvement in com-pression for short network delays
A path planning control for a vessel dynamic positioning system based on robust adaptive fuzzy strategy
The thrusters and propulsion propellers systems, as well as the operating situations, are all well-known nonlinearities which are caused less accuracy of the dynamic positioning system (DPS) of vessels in the path planning control process. In this study, to enhance the robust performance of the DPS, we proposed a robust adaptive fuzzy control model to reduce the effect of uncertainty problems and disturbances on the DPS. Firstly, the adaptive fuzzy controller with adaptive law is designed to adjust the membership function of the fuzzy controller to minimize the error in path planning control of the vessel. Secondly, the H∞ performance of robust tracking is proved by the Lyapunov theory. Moreover, compared to the other controller, a simulation experiment comprising two case studies confirmed the efficiency of the approach. Finally, the results showed that the proposed controller reaches control quality, performance and stability
Hilbert Space of Isomorphic Representations of Bosonized Chiral
We analyse the Hilbert space structure of the isomorphic gauge non-invariant
and gauge invariant bosonized formulations of chiral for the particular
case of the Jackiw-Rajaraman parameter . The BRST subsidiary conditions
are found not to provide a sufficient criterium for defining physical states in
the Hilbert space and additional superselection rules must to be taken into
account. We examine the effect of the use of a redundant field algebra in
deriving basic properties of the model. We also discuss the constraint
structure of the gauge invariant formulation and show that the only primary
constraints are of first class.Comment: LaTeX, 19 page
Measuring geometric phases with a dynamical quantum Zeno effect in a Bose-Einstein condensate
A closed-trajectory evolution of a quantum state generally imprints a phase
that contains both dynamical and geometrical contributions. While dynamical
phases depend on the reference system, geometric phase factors are uniquely
defined by the properties of the outlined trajectory. Here, we generate and
measure geometric phases in a Bose-Einstein condensate of Rb using a
combination of dynamical quantum Zeno effect and measurement-free evolution. We
show that the dynamical quantum Zeno effect can inhibit the formation of a
geometric phase without altering the dynamical phase. This can be used to
extract the geometric Aharonov-Anandan phase from any closed-trajectory
evolution without requiring knowledge or control of the Hamiltonian.Comment: 4+3 pages, 4+3 figure
Subprodutos da agroindústria da soja na alimentação de ruminantes.
bitstream/item/38616/1/Circular37.pd
Super-resolution, Extremal Functions and the Condition Number of Vandermonde Matrices
Super-resolution is a fundamental task in imaging, where the goal is to
extract fine-grained structure from coarse-grained measurements. Here we are
interested in a popular mathematical abstraction of this problem that has been
widely studied in the statistics, signal processing and machine learning
communities. We exactly resolve the threshold at which noisy super-resolution
is possible. In particular, we establish a sharp phase transition for the
relationship between the cutoff frequency () and the separation ().
If , our estimator converges to the true values at an inverse
polynomial rate in terms of the magnitude of the noise. And when no estimator can distinguish between a particular pair of
-separated signals even if the magnitude of the noise is exponentially
small.
Our results involve making novel connections between {\em extremal functions}
and the spectral properties of Vandermonde matrices. We establish a sharp phase
transition for their condition number which in turn allows us to give the first
noise tolerance bounds for the matrix pencil method. Moreover we show that our
methods can be interpreted as giving preconditioners for Vandermonde matrices,
and we use this observation to design faster algorithms for super-resolution.
We believe that these ideas may have other applications in designing faster
algorithms for other basic tasks in signal processing.Comment: 19 page
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