A Time-Periodic Lyapunov Approach for Motion Planning of Controllable Driftless Systems on SU(n)

For a right-invariant and controllable driftless system on SU(n), we consider a time-periodic reference trajectory along which the linearized control system generates su(n): such trajectories always exist and constitute the basic ingredient of Coron's Return Method. The open-loop controls that we propose, which rely on a left-invariant tracking error dynamics and on a fidelity-like Lyapunov function, are determined from a finite number of left-translations of the tracking error and they assure global asymptotic convergence towards the periodic reference trajectory. The role of these translations is to avoid being trapped in the critical region of this Lyapunov-like function. The convergence proof relies on a periodic version of LaSalle's invariance principle and the control values are determined by numerical integration of the dynamics of the system. Simulations illustrate the obtained controls for $n=4$ and the generation of the C--NOT quantum gate.Comment: Submitte

Levantamento detalhado de solos em uma área de reassentamento de colonos na Bacia do Jatobá - PE.

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Evapotranspiração de um pomar de mangueiras irrigadas na região do Submédio São Franscisco.

O presente trabalho objetivou determinar aevapotranspiração durante o ciclo produtivo da mangueira,variedade ?Tommy Atknis`, cultivada nas condições declima e solo da região do Submédio São Francisco

Determination of metabolite profiles in tropical wines by 1H NMR spectroscopy and chemometrics.

The aim of this work was to determine metabolite profiles of tropical wines produced in northeast Brazil, by using 1H NMR spectroscopy in comoination with chemometric methods to analyze and discrirninate wine samples from 2007 vintages produced by different wineries

ELKO Spinor Fields: Lagrangians for Gravity derived from Supergravity

Dual-helicity eigenspinors of the charge conjugation operator (ELKO spinor fields) belong -- together with Majorana spinor fields -- to a wider class of spinor fields, the so-called flagpole spinor fields, corresponding to the class-(5), according to Lounesto spinor field classification based on the relations and values taken by their associated bilinear covariants. There exists only six such disjoint classes: the first three corresponding to Dirac spinor fields, and the other three respectively corresponding to flagpole, flag-dipole and Weyl spinor fields. Using the mapping from ELKO spinor fields to the three classes Dirac spinor fields, it is shown that the Einstein-Hilbert, the Einstein-Palatini, and the Holst actions can be derived from the Quadratic Spinor Lagrangian (QSL), as the prime Lagrangian for supergravity. The Holst action is related to the Ashtekar's quantum gravity formulation. To each one of these classes, there corresponds a unique kind of action for a covariant gravity theory. Furthermore we consider the necessary and sufficient conditions to map Dirac spinor fields (DSFs) to ELKO, in order to naturally extend the Standard Model to spinor fields possessing mass dimension one. As ELKO is a prime candidate to describe dark matter and can be obtained from the DSFs, via a mapping explicitly constructed that does not preserve spinor field classes, we prove that in particular the Einstein-Hilbert, Einstein-Palatini, and Holst actions can be derived from the QSL, as a fundamental Lagrangian for supergravity, via ELKO spinor fields. The geometric meaning of the mass dimension-transmuting operator - leading ELKO Lagrangian into the Dirac Lagrangian - is also pointed out, together with its relationship to the instanton Hopf fibration.Comment: 11 pages, RevTeX, accepted for publication in Int.J.Geom.Meth.Mod.Phys. (2009

Far Infrared Slab Lensing and Subwavelength Imaging in Crystal Quartz

We examine the possibility of using negative refraction stemming from the phonon response in an anisotropic crystal to create a simple slab lens with plane parallel sides, and show that imaging from such a lens should be possible at room temperature despite the effects of absorption that are inevitably present due to phonon damping. In particular, we consider the case of crystal quartz, a system for which experimental measurements consistent with all-angle negative refraction have already been demonstrated. Furthermore, we investigate the possibility of subwavelength imaging from such materials, and show that it should be possible for certain configurations.Comment: 12 pages, 10 figure

Adverse Events among HIV/MDR-TB Co-Infected Patients Receiving Antiretroviral and Second Line Anti-TB Treatment in Mumbai, India.

Significant adverse events (AE) have been reported in patients receiving medications for multidrug- and extensively-drug-resistant tuberculosis (MDR-TB & XDR-TB). However, there is little prospective data on AE in MDR- or XDR-TB/HIV co-infected patients on antituberculosis and antiretroviral therapy (ART) in programmatic settings

Número de folhas e área foliar de banana 'BRS Princesa' produzida sob secamento parcial do sistema radicular.

Esse trabalho tem como objetivo avaliar o desenvolvimento vegetativo da bananeira cultivar Princesa, irrigada por gotejamento, submetida à redução de lâmina e frequência de alternância da irrigação. Foram avaliados na ocasião do florescimento o número de folhas e área foliar da cultivar ?Princesa? no seu segundo ciclo de produção sob a técnica de secamento parcial do sistema radicular (PRD). O experimento foi conduzido em delineamento em blocos casualizados em bananal implantado no município de Nova Porteirinha-MG, utilizando irrigação por gotejamento com duas linhas laterais por fileira de plantas, com seis emissores por touceira. Os tratamentos foram baseados na redução da lâmina calculada de irrigação em 50% da ETc, com frequência de alternância do lado da fileira irrigada (FA) de 7, 14 e 21 dias. De acordo a análise de variância não houve efeito de significância do manejo de irrigação para o número de folhas e área foliar. O número de folhas por planta e a área foliar não são influenciados pelo uso da PRD com 50% da ETc

Propriedades físico-hídricas de solos de uma área na Bacia do Jatobá - PE

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Coeficiente de cultura e produtividade da mangueira irrigada.

Data of solar radiation, soil heat flux and dry and wet bulbs air temperature were used in the elaboration of theabove canopy energy balance based on Bowen ratio. Also, data soil humidity profiles were used in thedetermination of the soil water balance of a dripping irrigated seven years old mango orchard, cv. ?Tommy Atkins’.The field experiment was conducted in the irrigated perimeter of Bebedouro, in Petrolina-PE, Brazil (Latitude:09009`S, Longitude: 40022`W; altitude: 365.5m), in the years of 1998 and 1999. The obtained results indicatedthat, in the submedian San Francisco river region soil and climate conditions, the mango orchard waterconsumption, represented by the corp coefficient (Kc), doesn't stay constant throughout the productive cycle, but itvaries as a function of the days after flowering(DAF) according to the following equation: Kc = 0.36 + 0.009(DAF) – 4.0 x 10-5 (DAF)2, with r2 = 0.79