29 research outputs found

    Demonstration of how the zeta function method for effective potential removes the divergences

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    The calculation of the minimum of the effective potential using the zeta function method is extremely advantagous, because the zeta function is regular at s=0s=0 and we gain immediately a finite result for the effective potential without the necessity of subtratction of any pole or the addition of infinite counter-terms. The purpose of this paper is to explicitly point out how the cancellation of the divergences occurs and that the zeta function method implicitly uses the same procedure used by Bollini-Giambiagi and Salam-Strathdee in order to gain finite part of functions with a simple pole.Comment: 9 page

    A Mathematical, Graphical and Visual Approach to Granular Synthesis Composition

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    We show a method for Granular Synthesis Composition based on a mathematical modeling for the musical gesture. Each gesture is drawn as a curve generated from a particular mathematical model (or function) and coded as a MATLAB script. The gestures can be deterministic through defining mathematical time functions, hand free drawn, or even randomly generated. This parametric information of gestures is interpreted through OSC messages by a granular synthesizer (Granular Streamer). The musical composition is then realized with the models (scripts) written in MATLAB and exported to a graphical score (Granular Score). The method is amenable to allow statistical analysis of the granular sound streams and the final music composition. We also offer a way to create granular streams based on correlated pair of grains parameters

    Codings for rhythm generation

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    In this work, we present a brief review of strategies to code rhythms and point to their possibilities and limitations in a unified way. We start by giving an overview of the representation (coding) of rhythms and their possible uses. Then we present different methods to analyse and generate rhythm patterns, which can be easily read by humans, through a simple algorithm.  We also aim to provide a general evaluation of their pros and cons regarding their use in composition and analysis. In a more abstract approach, we define Rhythm Spaces as sets of strings of symbols endowed with suitable operations and algorithms that can be applied to generate new and complex rhythm patterns. Our approach can be useful in order to provide suitable code/notation to be used in computer applications in rhythm analysis and composition

    Exponential Growth of Particle Number far from the Parametric Resonance Regime

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    Parametric resonance has received a considerable amount of interest as a good mathematical model to describe the initial stages of the reheating phase (matter creation) in inflationary cosmology. It is also known that exponential particle creation can occur in situations which do not fall in the parametric resonance regime characterized by oscillations of the inflaton field about its minimum. Here we present a new analytical approach to exponential particle production which can occur when the inflaton is far from the minimum of its potential. Crucial for this effect is a term in the equation of motion which acts like a negative mass square term, as occurs for tachyonic preheating and negative coupling particle production. Our techniques apply in models with a strong coupling between matter fields χ\chi and the inflaton ϕ\phi, or in some models in which the inflaton has a large amplitude of oscillation. Note that our analysis yields results which are quite model dependent. Exponential growth occurs in a model with interaction Lagrangian gMplϕχ2-g M_{pl}\phi\chi^2. However, for the interaction Lagrangian g2ϕ2χ2-g^2\phi^2\chi^2, our formalism shows that in the large coupling limit there can only be exponential particle production when ϕ\phi crosses 0.Parametric resonance has received a considerable amount of interest as a good mathematical model to describe the initial stages of the reheating phase (matter creation) in inflationary cosmology. It is also known that exponential particle creation can occur in situations which do not fall in the parametric resonance regime characterized by oscillations of the inflaton field about its minimum. Here we present a new analytical approach to exponential particle production which can occur when the inflaton is far from the minimum of its potential. Crucial for this effect is a term in the equation of motion which acts like a negative mass square term, as occurs for tachyonic preheating and negative coupling particle production. Our techniques apply in models with a strong coupling between matter fields χ\chi and the inflaton ϕ\phi, or in some models in which the inflaton has a large amplitude of oscillation. Note that our analysis yields results which are quite model dependent. Exponential growth occurs in a model with interaction Lagrangian gMplϕχ2-g M_{pl}\phi\chi^2. However, for the interaction Lagrangian g2ϕ2χ2-g^2\phi^2\chi^2, our formalism shows that in the large coupling limit there can only be exponential particle production when ϕ\phi crosses 0.Parametric resonance has received a considerable amount of interest as a good mathematical model to describe the initial stages of the reheating phase (matter creation) in inflationary cosmology. It is also known that exponential particle creation can occur in situations which do not fall in the parametric resonance regime characterized by oscillations of the inflaton field about its minimum. Here we present a new analytical approach to exponential particle production which can occur when the inflaton is far from the minimum of its potential. Crucial for this effect is a term in the equation of motion which acts like a negative mass square term, as occurs for tachyonic preheating and negative coupling particle production. Our techniques apply in models with a strong coupling between matter fields χ\chi and the inflaton ϕ\phi, or in some models in which the inflaton has a large amplitude of oscillation. Note that our analysis yields results which are quite model dependent. Exponential growth occurs in a model with interaction Lagrangian gMplϕχ2-g M_{pl}\phi\chi^2. However, for the interaction Lagrangian g2ϕ2χ2-g^2\phi^2\chi^2, our formalism shows that in the large coupling limit there can only be exponential particle production when ϕ\phi crosses 0.Parametric resonance has received a considerable amount of interest as a good mathematical model to describe the initial stages of the reheating phase (matter creation) in inflationary cosmology. It is also known that exponential particle creation can occur in situations which do not fall in the parametric resonance regime characterized by oscillations of the inflaton field about its minimum. Here we present a new analytical approach to exponential particle production which can occur when the inflaton is far from the minimum of its potential. Crucial for this effect is a term in the equation of motion which acts like a negative mass square term, as occurs for tachyonic preheating and negative coupling particle production. Our techniques apply in models with a strong coupling between matter fields χ\chi and the inflaton ϕ\phi, or in some models in which the inflaton has a large amplitude of oscillation. Note that our analysis yields results which are quite model dependent. Exponential growth occurs in a model with interaction Lagrangian gMplϕχ2-g M_{pl}\phi\chi^2. However, for the interaction Lagrangian g2ϕ2χ2-g^2\phi^2\chi^2, our formalism shows that in the large coupling limit there can only be exponential particle production when ϕ\phi crosses 0

    Genome of the Avirulent Human-Infective Trypanosome—Trypanosoma rangeli

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    Background: Trypanosoma rangeli is a hemoflagellate protozoan parasite infecting humans and other wild and domestic mammals across Central and South America. It does not cause human disease, but it can be mistaken for the etiologic agent of Chagas disease, Trypanosoma cruzi. We have sequenced the T. rangeli genome to provide new tools for elucidating the distinct and intriguing biology of this species and the key pathways related to interaction with its arthropod and mammalian hosts.  Methodology/Principal Findings: The T. rangeli haploid genome is ,24 Mb in length, and is the smallest and least repetitive trypanosomatid genome sequenced thus far. This parasite genome has shorter subtelomeric sequences compared to those of T. cruzi and T. brucei; displays intraspecific karyotype variability and lacks minichromosomes. Of the predicted 7,613 protein coding sequences, functional annotations could be determined for 2,415, while 5,043 are hypothetical proteins, some with evidence of protein expression. 7,101 genes (93%) are shared with other trypanosomatids that infect humans. An ortholog of the dcl2 gene involved in the T. brucei RNAi pathway was found in T. rangeli, but the RNAi machinery is non-functional since the other genes in this pathway are pseudogenized. T. rangeli is highly susceptible to oxidative stress, a phenotype that may be explained by a smaller number of anti-oxidant defense enzymes and heatshock proteins.  Conclusions/Significance: Phylogenetic comparison of nuclear and mitochondrial genes indicates that T. rangeli and T. cruzi are equidistant from T. brucei. In addition to revealing new aspects of trypanosome co-evolution within the vertebrate and invertebrate hosts, comparative genomic analysis with pathogenic trypanosomatids provides valuable new information that can be further explored with the aim of developing better diagnostic tools and/or therapeutic targets

    Pervasive gaps in Amazonian ecological research

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