Detecting unstable periodic spatio-temporal states of spatial extended chaotic systems

The method of detection of the unstable periodic spatio-temporal states of spatial extended chaotic systems has been proposed. The application of this method is illustrated by the consideration of two different systems: i) the fluid model of Pierce diode being one of the fundamental system of the physics of plasmas and microwave electronics and ii) the complex one-dimensional Ginzburg-Landau equation demonstrating different regimes of spatio-temporal chaos.Comment: 6 pages, 7 figure

Chaotic synchronization of coupled electron-wave systems with backward waves

The chaotic synchronization of two electron-wave media with interacting backward waves and cubic phase nonlinearity is investigated in the paper. To detect the chaotic synchronization regime we use a new approach, the so-called time scale synchronization [Chaos, 14 (3) 603-610 (2004)]. This approach is based on the consideration of the infinite set of chaotic signals' phases introduced by means of continuous wavelet transform. The complex space-time dynamics of the active media and mechanisms of the time scale synchronization appearance are considered.Comment: 11 pages, 7 figures, published in CHAOS, 15 (2005) 01370

Avaliação pós-colheita de cultivares de pêras produzidas no Submédio São Francisco.

O objetivo do presente trabalho é avaliar a qualidade pós-colheita de quatro cultivares de peras produzidas sob irrigação no Semiárido Brasileiro

Planform selection in two-layer Benard-Marangoni convection

Benard-Marangoni convection in a system of two superimposed liquids is investigated theoretically. Extending previous studies the complete hydrodynamics of both layers is treated and buoyancy is consistently taken into account. The planform selection problem between rolls, squares and hexagons is investigated by explicitly calculating the coefficients of an appropriate amplitude equation from the parameters of the fluids. The results are compared with recent experiments on two-layer systems in which squares at onset have been reported.Comment: 17 pages, 7 figures, oscillatory instability included, typos corrected, references adde

Amplitude equations for Rayleigh-Benard convective rolls far from threshold

An extension of the amplitude method is proposed. An iterative algorithm is developed to build an amplitude equation model that is shown to provide precise quantitative results even far from the linear instability threshold. The method is applied to the study of stationary Rayleigh-Benard thermoconvective rolls in the nonlinear regime. In particular, the generation of second and third spatial harmonics is analyzed. Comparison with experimental results and direct numerical calculations is also made and a very good agreement is found.Peer reviewe

Peanut clump virus and Polymyxa graminis interactions with pearl millet (Pennisetum glaucum [L.] R. Br.) and Sorghum(Sorghum bicolor [L.] Moench)

The susceptibility of 6 pearl millet (Ankoutess, ICMV IS 89305, ICMV IS 92222, ICMV IS 94206, Sadoré local and Zatib) and 6 sorghum (Irat 204, Mota Maradi, Nad 1, Sariaso 10, Sepon 82 and Zinder local) accessions to Peanut clump virus and its vector (Polymyxa graminis) was evaluated during the rainy season of 2002 under field conditions in Sadoré, Niger. The frequencies of infection of roots and leaves, analysed by a penicillinase-based DAS-ELISA, confirmed the differences among the pearl millet and sorghum accessions. In pearl millet, the virus was detected in roots and leaves, whereas in sorghum, infection was common in roots but rare in leaves. This was linked with the seed transmission of PCV in millet and not in sorghum. These results confirmed preliminary observations on the movement of the virus within these plant species, underlining the potential role of the viral P15 gene, a suppressor of post-transcriptional gene inactivation. Susceptibility to P. graminis f.sp. tropicalis was assessed under controlled conditions using a zoospore inoculation assay. Infection was quantified by a real-time quantitative PCR assay targeting the ribosomial DNA, and highlighting the differences between plant accessions and species. In addition to guidance on the selection of resistant cultivars, this study also sought to provide a toolbox for improving the understanding of the plant/vector/virus interaction

On the relation between fuzzy closing morphological operators, fuzzy consequence operators induced by fuzzy preorders and fuzzy closure and co-closure systems

In a previous paper, Elorza and Burillo explored the coherence property in fuzzy consequence operators. In this paper we show that fuzzy closing operators of mathematical morphology are always coherent operators. We also show that the coherence property is the key to link the four following families: fuzzy closing morphological operators, fuzzy consequence operators, fuzzy preorders and fuzzy closure and co-closure systems. This will allow to translate important well-known properties from the field of approximate reasoning to the field of image processing

Description of sensory profile of tropical wines of guard issued in the Valley of São Francisco, Northeast Brazil.

The objective of this study was to characterize the sensory profile of tropical wine of guard produced in the São Francisco Valley, Northeast Brazil. Two commercial wines, a varietal wine Touriga Nacional and an assemblage wine composed by Cabernet Sauvignon (60%), Syrah (30%) and Alicante Bouschet (10%) were kept for 12 months in oak barrel. Latter, the samples were coded with three-digit numbers and blind tested in standard crystal tasting glasses, model ISO, in aliquots of 40 mL at 18 °C by an expert panel of ten experts with over five years of experience in sensory wine analysis. Three evaluation sheets (descriptive, score and nonparametric) were used. The assemblage wine was characterized in flavor intensity and floral taste, vegetal and woody taste, and taste intensity. Touriga Nacional wine was more evident due to higher clarity, tone and visual intensity, olfactory persistence, fruity, toasty and woody aromas, bitter taste, fruity spice flavors, body, typicality and quality taste

"First pain" in humans: convergent and specific forebrain responses

<p>Abstract</p> <p>Background</p> <p>Brief heat stimuli that excite nociceptors innervated by finely myelinated (Aδ) fibers evoke an initial, sharp, well-localized pain ("first pain") that is distinguishable from the delayed, less intense, more prolonged dull pain attributed to nociceptors innervated by unmyelinated (C) fibers ("second pain"). In the present study, we address the question of whether a brief, noxious heat stimulus that excites cutaneous Aδ fibers activates a distinct set of forebrain structures preferentially in addition to those with similar responses to converging input from C fibers. Heat stimuli at two temperatures were applied to the dorsum of the left hand of healthy volunteers in a functional brain imaging (fMRI) paradigm and responses analyzed in a set of volumes of interest (VOI).</p> <p>Results</p> <p>Brief 41°C stimuli were painless and evoked only C fiber responses, but 51°C stimuli were at pain threshold and preferentially evoked Aδ fiber responses. Most VOI responded to both intensities of stimulation. However, within volumes of interest, a contrast analysis and comparison of BOLD response latencies showed that the bilateral anterior insulae, the contralateral hippocampus, and the ipsilateral posterior insula were preferentially activated by painful heat stimulation that excited Aδ fibers.</p> <p>Conclusions</p> <p>These findings show that two sets of forebrain structures mediate the initial sharp pain evoked by brief cutaneous heat stimulation: those responding preferentially to the brief stimulation of Aδ heat nociceptors and those with similar responses to converging inputs from the painless stimulation of C fibers. Our results suggest a unique and specific physiological basis, at the forebrain level, for the "first pain" sensation that has long been attributed to Aδ fiber stimulation and support the concept that both specific and convergent mechanisms act concurrently to mediate pain.</p