Existence and approximation of Hunt processes associated with generalized Dirichlet forms

We show that any strictly quasi-regular generalized Dirichlet form that satisfies the mild structural condition D3 is associated to a Hunt process, and that the associated Hunt process can be approximated by a sequence of multivariate Poisson processes. This also gives a new proof for the existence of a Hunt process associated to a strictly quasi-regular generalized Dirichlet form that satisfies SD3 and extends all previous results.Comment: Revised, shortened and improved versio

Zero-lag long-range synchronization via dynamical relaying

We show that simultaneous synchronization between two delay-coupled oscillators can be achieved by relaying the dynamics via a third mediating element, which surprisingly lags behind the synchronized outer elements. The zero-lag synchronization thus obtained is robust over a considerable parameter range. We substantiate our claims with experimental and numerical evidence of these synchronization solutions in a chain of three coupled semiconductor lasers with long inter-element coupling delays. The generality of the mechanism is validated in a neuronal model with the same coupling architecture. Thus, our results show that synchronized dynamical states can occur over long distances through relaying, without restriction by the amount of delay.Comment: 10 pages, 4 figure

Cultivo e uso de abóboras ornamentais.

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Planting density and number of stems for ecological crop determinate growth tomato.

Tomato growers adopting an ecologically based system have opted for determinate growth varieties due to their ease of staking and sprouting, and due to the fact that they have a shorter cycle, which reduces phytosanitary problems that usually occur towards the end of the growing season. This study aimed to evaluate yield components and fruit quality of ‘Floradade’ determinate growth tomato in an ecologically based production system with regard to plant density and number of stems per plant in two growing seasons, spring-summer (SS) and summer-fall (SF). Two experiments were conducted in Pelotas in the years 2010/2011 under open field conditions. Plants were trained with two or four stems and four plant densities were evaluated: 2.0; 2.5; 3.0 and 3.6 plants m-2in SS, and 1.5; 2.0; 2.5 and 3.0 plants m-2 in SF. The fruit number, fruit average weight, fruit yield, ascorbic acid content, total soluble solids and fruit pH were evaluated. The average fruit yield obtained in SF was on average 80% lower than that in SS. The increase of plant density and number of stems per plant led to an increase in fruit number and fruit yield in the two crop seasons. There was an increase in total soluble solids and reduction in the ascorbic acid content of the fruit. Two stemsper plant and plant density of 3.0 plants m-2 are recommended for the ‘Floradade’ tomato crop under an ecological production system and SS crop conditions

Cultivo orgânico do morangueiro: densidade de plantio, crescimento e produtividade de cultivares de ?dia neutro?

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All-Lignin Polyelectrolyte Multilayers as Renewable and Biodegradable Nanofiltration Membranes

Polyelectrolyte multilayers have proven to be versatile materials for the fabrication of nanofiltration membranes with a wide range of properties and applications. A problem of these membranes is that they are made of nonrenewable and nonbiodegradable fossil resources, rendering them unsustainable for the future. To solve this, we present lignin as a renewable and biodegradable alternative for the fabrication of polyelectrolyte multilayer membranes (PEMMs). Here, lignosulfonate was used as a polyanion in combination with modified Kraft lignin as a polycation in a layer-by-layer self-assembly process to coat hollow fiber support membranes to obtain so-called all-lignin PEMMs. The PEMMs showed loose nanofiltration properties (molecular weight cutoff &gt; 1 kDa, MgSO4 retention 20%) that could easily be fine-tuned by changing the ionic strength of the coating solutions. Furthermore, the lignin PEMMs have excellent stability in saline solutions of up to 5 M NaCl and were stable in a pH range from 1 to 11. Additionally, the lignin retained its biodegradable properties in the presence of laccase enzymes after forming a PEMM. Our results indicate that lignins are a suitable candidate for replacing fossil-based polyelectrolytes for the fabrication of chemically stable, renewable, and biodegradable PEMMs.</p

Zero-lag long-range synchronization via dynamical relaying

4 pages.-- PACS numbers: 42.65.Sf, 05.45.Xt, 42.55.Px.-- ArXiv pre-print: http://arxiv.org/abs/nlin/0605036.-- Final full-text version of the paper available at: http://dx.doi.org/10.1103/PhysRevLett.97.123902.We show that isochronous synchronization between two delay-coupled oscillators can be achieved by relaying the dynamics via a third mediating element, which surprisingly lags behind the synchronized outer elements. The zero-lag synchronization thus obtained is robust over a considerable parameter range. We substantiate our claims with experimental and numerical evidence of such synchronization solutions in a chain of three coupled semiconductor lasers with long inter-element coupling delays. The generality of the mechanism is validated in a neuronal model with the same coupling architecture. Thus, our results show that zero-lag synchronized chaotic dynamical states can occur over long distances through relaying, without restriction by the amount of delay.Research supported by the Ministerio de Educación y Ciencia (Spain) and FEDER (projects CONOCE2, AUCOFLUC and LASEA) and by the Generalitat de Catalunya. In addition, I. F. acknowledges funding from the FWO under Contract No. GP06704-FWOSL21

Multiple micro-optical atom traps with a spherically aberrated laser beam

We report on the loading of atoms contained in a magneto-optic trap into multiple optical traps formed within the focused beam of a CO_{2} laser. We show that under certain circumstances it is possible to create a linear array of dipole traps with well separated maxima. This is achieved by focusing the laser beam through lenses uncorrected for spherical aberration. We demonstrate that the separation between the micro-traps can be varied, a property which may be useful in experiments which require the creation of entanglement between atoms in different micro-traps. We suggest other experiments where an array of these traps could be useful.Comment: 10 pages, 3 figure

Zeros of Rydberg-Rydberg Foster Interactions

Rydberg states of atoms are of great current interest for quantum manipulation of mesoscopic samples of atoms. Long-range Rydberg-Rydberg interactions can inhibit multiple excitations of atoms under the appropriate conditions. These interactions are strongest when resonant collisional processes give rise to long-range C_3/R^3 interactions. We show in this paper that even under resonant conditions C_3 often vanishes so that care is required to realize full dipole blockade in micron-sized atom samples.Comment: 10 pages, 4 figures, submitted to J. Phys.

Desempenho de cultivares de tomateiro em diferentes ambientes de cultivo e sistema ecológico de produção.

O tomate é uma hortaliça de grande importância na mesa dos brasileiros, sendo que frutos produzidos de forma ecológica são preferidos e mais saudáveis. Para a produção exitosa de tomate neste sistema é necessária a utilização de cultivares adaptadas, dando-se preferência por aquelas de polinização aberta. A utilização de ambiente protegido tem viabilizado o cultivo do tomateiro em muitas regiões, com possibilidade de estender o período produtivo. O objetivo deste trabalho foi avaliar a produtividade e a duração do ciclo de duas cultivares de tomateiro produzidas a campo e em ambiente protegido em sistema de produção de base ecológica. O experimento foi realizado na Estação Experimental Cascata (Embrapa Clima Temperado), Pelotas, Rio Grande do Sul. Foram avaliados dois genótipos ?Rose de Berne? e ?Maçã?. O controle de insetos e doenças foi baseado na legislação brasileira de orgânicos. Após cada colheita, os frutos foram pesados e classificados, e ao final do período experimental foi determinada a produção de frutos por planta, número e massa média de frutos, e duração total do ciclo. ?Maçã? produziu mais frutos que ?Rose de Berne? por ser do tipo cereja, porém a produtividade das duas não diferiu entre si nem entre ambientes, mantendo em média 6,5 kg m-2. O descarte foi maior para ?Rose de Berne?. A massa média dos frutos a campo foi maior que na estufa. O ciclo de cultivo no ambiente protegido foi de 126 dias para ambas cultivares, sendo que a campo, ?Maçã? teve ciclo de apenas 109 dias e ?Rose de Berne? de 130 dias. A produtividade de ambas cultivares e ambientes foi satisfatória. O ambiente protegido não diferiu em produtividade com o campo, porém permitiu prolongar o ciclo de produção da cultivar ?Maçã?. Perdas podem ser reduzidas se forem realizadas colheitas mais frequentes