8,197 research outputs found

    Spinors Fields in Co-dimension One Braneworlds

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    In this work we analyze the zero mode localization and resonances of 1/2−1/2-spin fermions in co-dimension one Randall-Sundrum braneworld scenarios. We consider delta-like, domain walls and deformed domain walls membranes. Beyond the influence of the spacetime dimension DD we also consider three types of couplings: (i) the standard Yukawa coupling with the scalar field and parameter η1\eta_1, (ii) a Yukawa-dilaton coupling with two parameters η2\eta_2 and λ\lambda and (iii) a dilaton derivative coupling with parameter hh. Together with the deformation parameter ss, we end up with five free parameter to be considered. For the zero mode we find that the localization is dependent of DD, because the spinorial representation changes when the bulk dimensionality is odd or even and must be treated separately. For case (i) we find that in odd dimensions only one chirality can be localized and for even dimension a massless Dirac spinor is trapped over the brane. In the cases (ii) and (iii) we find that for some values of the parameters, both chiralities can be localized in odd dimensions and for even dimensions we obtain that the massless Dirac spinor is trapped over the brane. We also calculated numerically resonances for cases (ii) and (iii) by using the transfer matrix method. We find that, for deformed defects, the increasing of DD induces a shift in the peaks of resonances. For a given λ\lambda with domain walls, we find that the resonances can show up by changing the spacetime dimensionality. For example, the same case in D=5D=5 do not induces resonances but when we consider D=10D=10 one peak of resonance is found. Therefore the introduction of more dimensions, diversely from the bosonic case, can change drastically the zero mode and resonances in fermion fields.Comment: 28 pages, 7 figure

    Affective Science

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    Decay of distance autocorrelation and Lyapunov exponents

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    This work presents numerical evidences that for discrete dynamical systems with one positive Lyapunov exponent the decay of the distance autocorrelation is always related to the Lyapunov exponent. Distinct decay laws for the distance autocorrelation are observed for different systems, namely exponential decays for the quadratic map, logarithmic for the H\'enon map and power-law for the conservative standard map. In all these cases the decay exponent is close to the positive Lyapunov exponent. For hyperbolic conservative systems, the power-law decay of the distance autocorrelation tends to be guided by the smallest Lyapunov exponent.Comment: 7 pages, 8 figure

    Supersymmetrization of the Radiation Damping

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    We construct a supersymmetrized version of the model to the radiation damping \cite{03} introduced by the present authors \cite{ACWF}. We dicuss its symmetries and the corresponding conserved Noether charges. It is shown this supersymmetric version provides a supersymmetric generalization of the Galilei algebra obtained in \cite{ACWF}. We have shown that the supersymmetric action can be splited into dynamically independent external and internal sectors.Comment: 9 page

    Rhizosphere microbial community composition of common beans with different levels of resistance to Fusarium oxysporum.

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    Microbial communities in the rhizosphere make significant contributions to plant health, growth and protection against soil pathogens. Plants can take advantage of their rhizosphere microbiomes to fend off pathogens, avoiding microbial infections. Here, we aimed to identify potential microbial groups and functional traits correlated to the suppression of the soil borne Microbial diversity and functioning in the soil ecosystem 145 pathogen Fusarium oxysporum. Through shotgun metagenomics we investigated the rhizosphere microbial communities of four common bean cultivars with different levels of resistance to the fungus, ranging from susceptible to resistant. Plants were grown in mesocosms experiments with two contrasting soils, i.e. Amazon Dark Earth (ADE) and an agricultural soil (AS). The soils presented clear differences in chemical properties, and ADE hosts higher microbial diversity than AS. Chemical analysis indicated a significant increase of pH, Ca, Fe, sum of bases and base saturation, and decrease of K, Mg, exchangeable Al, and Mn in rhizosphere of both soil types. Quantitative PCR showed an increase of 16S rRNA copy number with the increase resistance to the fungus in ADE soil. The rhizosphere of the four bean cultivars is dominated by the same bacterial phyla Proteobacteria, Actinobacteria, Firmicutes, and Chloroflexi, albeit in different relative abundance between soil types. The community structure of rhizosphere was different from the bulk soil, revealing the selection process in this environment. In ADE soil, the most resistant cultivar presented higher taxonomic diversity when compared to other cultivars; in contrast, the functional diversity was lower. Comparing the resistant to the susceptible cultivars there was an increase of Nitrospirae, Solibacteres, Spirochaeta and Chryosiogenetes bacterial classes in the resistant. Also, resistant cultivar presented high number of sequences affiliated to the family Pseudomonadaceae and to the genera Bacillus and Solibacter. Interestingly, the resistant and moderately resistant cultivars, presented high proportion of sequences related to bacteriocin, a narrow spectrum antibiotic, which suggests its role on pathogen suppression. Preliminary analysis showed that the selection of the microbial communities inhabiting the common bean rhizosphere is cultivar and soil type dependent. Further analysis will search for bacterial groups potentially related to the fungal antagonism. FAPESP 2014/03217-3

    Analysis of the rhizosphere microbial communities of common beans resistant and susceptible to Fusarium oxysporum.

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    The rhizosphere is the narrow zone of soil around the living plant roots that is influenced by the activity of the plants. Many beneficial microorganisms in the rhizosphere provide plants with mineral nutrients, phytohormones, and also help to protect the plant against soil-borne pathogens. Microbiological studies are addressed to understand how rhizosphere microorganisms are recruited from soil and either benefit or harm plant growth, nutrition and health. Here, we aimed to identify potential microbial groups and functional traits correlated to the suppression of the soil borne pathogen Fusarium oxysporum, the causal agent of Fusarium wilt on common beans. We used shotgun metagenomics to investigate the rhizosphere microbiome of two common bean cultivars classified as resistant (Milênio) and susceptible (Alvorada). Plants were grown in mesocosms experiments in Amazon Dark Earth, a soil with high microbial diversity. Chemical analysis indicated a significant increase of pH, Ca, Fe, Zn, Mn, B, nitrate, cation exchange capacity, sum of bases and base saturation in rhizosphere of both common bean types. The microbial community structure of rhizosphere was different from the bulk soil in a deeper taxonomic classification (genera), revealing the selection process in this environment. Quantitative PCR showed an increase of 16S rRNA copy number with the increase resistance to the fungus in ADE soil. The resistant cultivar presented higher taxonomic diversity but lower functional diversity. The most abundant phyla in rhizosphere were Proteobacteria (41%), Actinobacteria (31%), Firmicutes (5%), Acidobacteria (3%) and Chloroflexi (3%). The resistant cultivar presented more abundance of the phyla Chlamydiae, Spirochaetes, Deinococcus-Thermus and Chrysiogenetes in comparison to the susceptible one and bulk soil. Comparing the resistant to the susceptible cultivar in a finer taxonomic level, 24 genera presented higher abundance in the resistant one, highlighting Bacillus and Pseudomonas. Preliminary analysis showed that there is a specific selection of the microbial communities inhabiting the rhizosphere of a resistant common bean cultivar. Further analysis will combine 16S rRNA gene sequencing and metatranscriptome for a deep taxonomical and functional analysis

    Short-time Dynamics of Percolation Observables

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    We consider the critical short-time evolution of magnetic and droplet-percolation order parameters for the Ising model in two and three dimensions, through Monte-Carlo simulations with the (local) heat-bath method. We find qualitatively different dynamic behaviors for the two types of order parameters. More precisely, we find that the percolation order parameter does not have a power-law behavior as encountered for the magnetization, but develops a scale (related to the relaxation time to equilibrium) in the Monte-Carlo time. We argue that this difference is due to the difficulty in forming large clusters at the early stages of the evolution. Our results show that, although the descriptions in terms of magnetic and percolation order parameters may be equivalent in the equilibrium regime, greater care must be taken to interprete percolation observables at short times. In particular, this concerns the attempts to describe the dynamics of the deconfinement phase transition in QCD using cluster observables.Comment: 5 pages, 4 figure
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