Stochastic stability versus localization in chaotic dynamical systems

We prove stochastic stability of chaotic maps for a general class of Markov random perturbations (including singular ones) satisfying some kind of mixing conditions. One of the consequences of this statement is the proof of Ulam's conjecture about the approximation of the dynamics of a chaotic system by a finite state Markov chain. Conditions under which the localization phenomenon (i.e. stabilization of singular invariant measures) takes place are also considered. Our main tools are the so called bounded variation approach combined with the ergodic theorem of Ionescu-Tulcea and Marinescu, and a random walk argument that we apply to prove the absence of ``traps'' under the action of random perturbations.Comment: 27 pages, LaTe

Distillation methods affect the chemical composition of Varronia curassavica Jacq, essential oil?

The objective of this work was to evaluate the chemical composition of essential oil from Varronia curassavica Jacq. obtained by microwave (MI) and hydrodistillation (HD) extraction methods. The MI method tested three powers (500, 600, and 700W), three distillation times (20, 30, and 40 min.), and three water volumes (0, 25, and 50 mL per sample). The HD method tested three distillation times (100, 120, and 140 min.) and three water volumes (1.0, 1.5, and 2.0 L per 3-liter flask). The essential oils were analyzed by GC/MS-FID. The optimal condition for the essential oil extraction by the MI method was 700W for 40 min. (3.28%), regardless of the volume of water. In its turn, the best condition for essential oil extraction by the HD method was 120 min. with 1.0 L of water per flask (3.34%). The most abundant compounds for MI (700 W for 40 min. without water) were shyobunol (26.53%) and bicyclogermacrene (4.96%); and the most abundant compounds for HD (120 min. with 1.0 L of water/flask) were shyobunol (24.00%) and germacrene D-4-ol (10.23%). Methyl farnesoate (2E, 6E) and farnesyl acetate (2Z, 6E) were not detected in the essential oil extracted by HD; however, they were identified by the MI method. By increasing the distillation time and/or volume of water in HD, a reduction was observed for the content of the chemical compounds -elemene (from 1.23 to 0.97%), Ecaryophyllene (from 5.49 to 4.35%), -humulene (from 1.80 to 1.43%), alloaromadendrene (from 1.78 to 1.44%), bicyclogermacrene (from 5.63 to 4.55%), and germacrene D-4-ol (from 11.40 to 9.86%). Power, extraction time, and their interactions influenced the content of essential oil obtained by microwave extraction (MI). Within each power, the highest essential oil content was extracted at the longest distillation time (40 min.), except for 600W, where no significant difference was detected between 30 and 40 min. The optimal essential oil contents for both extraction methods were statically similar by the t-test for dependent samples. However, the MI method presents advantages, such as shorter distillation time and less energy and water consumption

Chaotic Cascades with Kolmogorov 1941 Scaling

We define a (chaotic) deterministic variant of random multiplicative cascade models of turbulence. It preserves the hierarchical tree structure, thanks to the addition of infinitesimal noise. The zero-noise limit can be handled by Perron-Frobenius theory, just as the zero-diffusivity limit for the fast dynamo problem. Random multiplicative models do not possess Kolmogorov 1941 (K41) scaling because of a large-deviations effect. Our numerical studies indicate that deterministic multiplicative models can be chaotic and still have exact K41 scaling. A mechanism is suggested for avoiding large deviations, which is present in maps with a neutrally unstable fixed point.Comment: 14 pages, plain LaTex, 6 figures available upon request as hard copy (no local report #

Analysis of genetic diversity of Hyptis pectinata (L.) Poit. plants using ISSR markers.

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Precision measurement of the half-life and the decay branches of 62Ga

In an experiment performed at the Accelerator Laboratory of the University of Jyvaskyla, the beta-decay half-life of 62Ga has been studied with high precision using the IGISOL technique. A half-life of T1/2 = 116.09(17)ms was measured. Using beta-gamma coincidences, the gamma intensity of the 954keV transition and an upper limit of the beta-decay feeding of the 0+_2 state have been extracted. The present experimental results are compared to previous measurements and their impact on our understanding of the weak interaction is discussed.Comment: 7 pages, 7 figures, submitted to EPJ

Genetic divergence in basil cultivars and hybrids.

Basil is an aromatic herb that stands out fo its economic importance. It is consumed in natura and sed to obtain essential oil. The cultivation of this species in several regions of the world has allowed variations by natural crosses and euploidy, leading to the wide genetic variability found nowadays. Considering the importance of this species, we aimed to analyze the genetic diversity of 27 basil genotypes using ISSR molecular markers. Fourteen primers were employed for DNA amplification, resulting in 86% polymorphism. Based on the Jaccard?s dissimilarity index, the highest index (0.80) was observed between the individuals BAS001 and BAS012, while the lowest index (0.18) was detected between the genotypes BAS014 and BAS015. The genetic similarity among individuals was calculated, forming four distinct clusters. Most individuals (40.7%) were allocated in cluster I. The polymorphic information content (PIC) (0.89) indicated considerable levels of genetic diversity among genotypes. In this sense, the ISSR markers were efficient in the detection of polymorphisms between the accessions, suggesting the genetic variability of the collection. This result demonstrates the importance of the use of molecular markers and the advantages that this information provides to the breeding of the species. O manjericão é uma erva aromática que se destaca por possuir importância econômica. É consumido in natura e também utilizado na obtenção de óleo essencial. O cultivo desta espécie em diversas regiões do mundo permitiu que surgissem variações mediante cru-zamentos naturais e euploidia, ocasionando a ampla variabilidade genética existente. Considerando a importância desta espécie, este trabalho teve como objetivo analisar a diversidade genética de 27 genótipos de manjericão usando marcadores moleculares ISSR. Qua-torze primers foram utilizados para amplificação do DNA, resultando em 86% de polimorfismo. Com base no índice de dissimilaridade de Jaccard, observou-se o maior índice (0,80) entre os indivíduos BAS001 e BAS012, enquanto que o menor índice de dissimilari-dade (0,18) foi detectado entre os genótipos BAS014 e BAS015. A semelhança genética entre indivíduos foi calculada, formando quatro grupos distintos. A maioria dos indivíduos (40,7%) foi agrupada no grupo I. O conteúdo de informação polimórfica (PIC) (0,89) indicou níveis consideráveis de diversidade genética entre os genótipos. Neste sentido, os marcadores ISSR foram eficientes na detecção de polimorfismos entre os acessos e confirmaram que é possível inferir a variabilidade genética na coleção. Isso demonstra a importância do uso de marcadores moleculares e as vantagens que esta informação pode oferecer ao melhoramento genético das espécies

First observation of 54Zn and its decay by two-proton emission

The nucleus 54Zn has been observed for the first time in an experiment at the SISSI/LISE3 facility of GANIL in the quasi-fragmentation of a 58Ni beam at 74.5 MeV/nucleon in a natNi target. The fragments were analysed by means of the ALPHA-LISE3 separator and implanted in a silicon-strip detector where correlations in space and time between implantation and subsequent decay events allowed us to generate almost background free decay spectra for about 25 different nuclei at the same time. Eight 54Zn implantation events were observed. From the correlated decay events, the half-life of 54Zn is determined to be 3.2 +1.8/-0.8 ms. Seven of the eight implantations are followed by two-proton emission with a decay energy of 1.48(2) MeV. The decay energy and the partial half-life are compared to model predictions and allow for a test of these two-proton decay models.Comment: 4 pages, 4 figures, accepted for publication in PR

On the discovery of doubly-magic 48^{48}Ni

The paper reports on the first observation of doubly-magic Nickel-48 in an experimental at the SISSI/LISE3 facility of GANIL. Four Nickel-48 isotopes were identified. In addition, roughly 100 Nickel-49, 50 Iron-45, and 290 Chromium-42 isotopes were observed. This opens the possibility to search for two-proton emission from these nuclei.Comment: 4 pages, 3 figures, accepted for publication in Phys. Rev. Let