Critical properties of an aperiodic model for interacting polymers

We investigate the effects of aperiodic interactions on the critical behavior of an interacting two-polymer model on hierarchical lattices (equivalent to the Migadal-Kadanoff approximation for the model on Bravais lattices), via renormalization-group and tranfer-matrix calculations. The exact renormalization-group recursion relations always present a symmetric fixed point, associated with the critical behavior of the underlying uniform model. If the aperiodic interactions, defined by s ubstitution rules, lead to relevant geometric fluctuations, this fixed point becomes fully unstable, giving rise to novel attractors of different nature. We present an explicit example in which this new attractor is a two-cycle, with critical indices different from the uniform model. In case of the four-letter Rudin-Shapiro substitution rule, we find a surprising closed curve whose points are attractors of period two, associated with a marginal operator. Nevertheless, a scaling analysis indicates that this attractor may lead to a new critical universality class. In order to provide an independent confirmation of the scaling results, we turn to a direct thermodynamic calculation of the specific-heat exponent. The thermodynamic free energy is obtained from a transfer matrix formalism, which had been previously introduced for spin systems, and is now extended to the two-polymer model with aperiodic interactions.Comment: 19 pages, 6 eps figures, to appear in J. Phys A: Math. Ge

First measurements of the flux integral with the NIST-4 watt balance

In early 2014, construction of a new watt balance, named NIST-4, has started at the National Institute of Standards and Technology (NIST). In a watt balance, the gravitational force of an unknown mass is compensated by an electromagnetic force produced by a coil in a magnet system. The electromagnetic force depends on the current in the coil and the magnetic flux integral. Most watt balances feature an additional calibration mode, referred to as velocity mode, which allows one to measure the magnetic flux integral to high precision. In this article we describe first measurements of the flux integral in the new watt balance. We introduce measurement and data analysis techniques to assess the quality of the measurements and the adverse effects of vibrations on the instrument.Comment: 7 pages, 8 figures, accepted for publication in IEEE Trans. Instrum. Meas. This Journal can be found online at http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=1

Crescimento micelial de isolados de Fusarium sp., Scytalidium sp., Lasiodiplodia sp. e Phytophthora sp., causadores de podridões radiculares em mandioca, sob diferentes temperaturas.

A podridão radicular é uma das doenças mais destrutivas da cultura da mandioca, provocando prejuízos econômicos e redução da produção. Essa enfermidade pode ser causada por um complexo de patógenos, que incluem espécies do gênero Fusarium sp. e Phytophthora sp., além de outros agentes causais como Scytalidium sp. e Lasiodiplodia sp.

Caracterização molecular de populações de Fusarium oxysporum f. sp. cubense em regiões produtoras de banana na Bahia.

O mal-do-Panamá, causado pelo fungo Fusarium oxysporum f. sp. cubense (Foc), é uma das doenças mais destrutivas da bananeira, sendo considerada entre as cinco doenças economicamente mais importantes de todos os tempos. O fato de ser causada por um fungo do solo que, mesmo na ausência da cultura, sobrevive por períodos prolongados, faz com que a medida de controle mais efetiva seja o uso de variedades resistentes. Desta forma, o projeto tem como objetivo caracterizar populações brasileiras de Foc por meio de marcadores SSR

Coleção Biológica de trabalho de Fusarium oxysporum f. sp. Cubense: do Laboratório de Fitopatologia.

A cultura da bananeira (Musa spp.) é a base econômica de muitas nações. E a banana, por sua vez, é a fruta mais consumida no mundo, sendo para alguns, item de segurança alimentar. A bananicultura está entre as atividades agrícolas de maior expressão econômica e social no Brasil.bitstream/item/56745/1/folder-colecao-biologica-de-trabalho-de-fusarium-oxysporum-INTERNET-2.pd

Predicting Intermediate Storage Performance for Workflow Applications

Configuring a storage system to better serve an application is a challenging task complicated by a multidimensional, discrete configuration space and the high cost of space exploration (e.g., by running the application with different storage configurations). To enable selecting the best configuration in a reasonable time, we design an end-to-end performance prediction mechanism that estimates the turn-around time of an application using storage system under a given configuration. This approach focuses on a generic object-based storage system design, supports exploring the impact of optimizations targeting workflow applications (e.g., various data placement schemes) in addition to other, more traditional, configuration knobs (e.g., stripe size or replication level), and models the system operation at data-chunk and control message level. This paper presents our experience to date with designing and using this prediction mechanism. We evaluate this mechanism using micro- as well as synthetic benchmarks mimicking real workflow applications, and a real application.. A preliminary evaluation shows that we are on a good track to meet our objectives: it can scale to model a workflow application run on an entire cluster while offering an over 200x speedup factor (normalized by resource) compared to running the actual application, and can achieve, in the limited number of scenarios we study, a prediction accuracy that enables identifying the best storage system configuration

Caracterização de isolados de Fusarium oxysporum f. sp. Cubense por marcadores SSR e compatibilidade vegetativa.

O mal-do-Panamá, causado pelo fungo Fusarium oxysporum f. sp. cubense (Foc), é uma das doenças mais destrutivas da bananeira. A medida de controle mais efetiva é o uso de variedades resistentes. O surgimento de novas raças é preocupação constante e fator desafiador para os programas de melhoramento visando resistência à doença

The two-component Beta-t-QVAR-M-lev: a new forecasting model

We introduce a new joint model of expected return and volatility forecasting, namely the two-component Beta-t-QVAR-M-lev (quasi-vector autoregression in-mean with leverage). The maximum likelihood estimator for the two-component Beta-t-QVAR-M-lev is an extension of theoretical results of the one-component Beta-t-QVAR-M. We compare the volatility forecasting performance of the two-component Beta-t-QVAR-M-lev and two-component GARCH-M (generalized autoregressive conditional heteroscedasticity), also considering their one-component frameworks. The results for G20 stock market indices indicate that the forecasting performance of the two-component Beta-t-QVAR-M-lev is superior compared with the two-component GARCH-M and their one-component versions