Danos ocasionados por Chinavia impicticornis (Stal) e Piezodorus guildinii (West.) (Hemiptera: Pentatomidae) em sementes de soja.

Experimentos realizados na soja, cv. NK 3363, com C. impicticornis e P. guildinii conduzidos em campo com gaiolas (1 x 1 x 1,2 m), em Ponta Grossa, Paraná, na safra de 2010/2011, tiveram como objetivo caracterizar e avaliar os danos ocasionados pela alimentação destes insetos. As plantas foram infestadas com diferentes níveis populacionais (0, 2 e 3 adultos/m), em diferentes fases fenológicas, sendo elas: início do desenvolvimento do grão a maturação (R5.1-R9); 25% a 50% de granação a maturação (R5.3-R9); semente completamente cheia a maturação (R6-R9). Foram analisadas: retenção foliar; germinação; danos estimados com análise de tetrazólio (classificados de 1 a 8, número total de sementes danificadas; e de 6 a 8, número total de sementes inviabilizadas). Os dados foram submetidos à análise de variância, e médias comparadas pelo teste de Tukey (p ? 0,05) . O maior índice de retenção foliar foi de 3,8 (21% a 40% de hastes verdes), referente às plantas infestadas com dois P. guildinii/m no período mais longo de infestação (61 dias, de R5.1 a R9), que no mesmo período, mas com três adultos/m, também causou o menor número de sementes germinadas (66,5%). A infestação com C. impicticornis causou a menor porcentagem de germinação (76,5%) no período de R5.3-R9, com dois adultos/m. As maiores porcentagens médias de sementes danificadas ocorreram nas infestações em R5.1-R9 com dois e três adultos/m de P. guildinii, respectivamente de 63,6% e 68,0%. C. impicticornis afetou o maior número de sementes (cerca de 54,0%) nas infestações em R6 com dois insetos/m. P. guildinii ocasionou os danos mais severos (36,0% de sementes inviabilizadas) em infestações no período mais longo (R5.1-R9). Não foram observadas diferenças significativas entre os períodos de infestação com dois e três insetos/m. A maior redução da viabilidade e do vigor das sementes foi ocasionada pelas infestações em R5.1 com três adultos/m de P. guildinii, obtendo-se apenas 64,0% de sementes viáveis e vigor de 38,7%

Physics of Psychophysics: Stevens and Weber-Fechner laws are transfer functions of excitable media

Sensory arrays made of coupled excitable elements can improve both their input sensitivity and dynamic range due to collective non-linear wave properties. This mechanism is studied in a neural network of electrically coupled (e.g. via gap junctions) elements subject to a Poisson signal process. The network response interpolates between a Weber-Fechner logarithmic law and a Stevens power law depending on the relative refractory period of the cell. Therefore, these non-linear transformations of the input level could be performed in the sensory periphery simply due to a basic property: the transfer function of excitable media.Comment: 4 pages, 5 figure

Probing the Statistical Properties of Unknown Texts: Application to the Voynich Manuscript

While the use of statistical physics methods to analyze large corpora has been useful to unveil many patterns in texts, no comprehensive investigation has been performed on the interdependence between syntactic and semantic factors. In this study we propose a framework for determining whether a text (e.g., written in an unknown alphabet) is compatible with a natural language and to which language it could belong. The approach is based on three types of statistical measurements, i.e. obtained from first-order statistics of word properties in a text, from the topology of complex networks representing texts, and from intermittency concepts where text is treated as a time series. Comparative experiments were performed with the New Testament in 15 different languages and with distinct books in English and Portuguese in order to quantify the dependency of the different measurements on the language and on the story being told in the book. The metrics found to be informative in distinguishing real texts from their shuffled versions include assortativity, degree and selectivity of words. As an illustration, we analyze an undeciphered medieval manuscript known as the Voynich Manuscript. We show that it is mostly compatible with natural languages and incompatible with random texts. We also obtain candidates for keywords of the Voynich Manuscript which could be helpful in the effort of deciphering it. Because we were able to identify statistical measurements that are more dependent on the syntax than on the semantics, the framework may also serve for text analysis in language-dependent applications

O ENSINO DA GEOMORFOLOGIA NAS ESCOLAS: REFLEXÕES A PARTIR DA ANÁLISE DO LIVRO DIDÁTICO DE GEOGRAFIA

O trabalho discute sobre a importância do livro didático para o ensino da Geomorfologia na escola básica. No primeiro momento é ressaltada a importância do livro no ensino escolar, sendo um recurso de construção do conhecimento geográfico e geomorfológico. No segundo momento é feita a análise do livro didático “Geografia: o espaço natural e a ação humana” referente ao capítulo que aborda os conhecimentos geomorfológicos, para verificar a relação entre o conhecimento escolar e científico

Método de pontos interiores barreira logarítmica preditor-corretor especializado para o problema de regressão pela norma Lp

The logaritmie barrier and predictor-corretor interior point methods are applied to the Lp norm fitting problem exploiting the matrix structure in order to obtain an efficient implementation.. The fitting problem has numerous applications in various areas. The 2-norin is very popular, among other reasons, for allowing a direct solution. The 1-norin allows the reduction of the effect of outliers while the ∞-norin provides protection against the worst case. The pnorm allows to think these characteristics in different ways adapting the method to the problem to be solved. The interior point method implementation to be developed is compared with existing methods.Os métodos de pontos interiores barreira logarítmica e preditor-corretor são aplicados ao problema de regressão pela norma Lp com algumas particularidades com o objetivo de obter uma implementação eficiente. O problema de regressão tem inúmeras aplicações em diversas áreas. A norma-2 é muito popular, entre outros motivos, por permitir uma solução direta. Por sua vez, a norma-1 permite reduzir o efeito de pontos discrepantes enquanto que a norma-∞ garante proteção contra o pior caso. A norma-p permite pensar estas características de diferentes formas, adaptando o método ao problema a ser resolvido. A implementação do método de pontos interiores desenvolvida é comparada com métodos existentes.21923

Polarized Dirac fermions in de Sitter spacetime

The tetrad gauge invariant theory of the free Dirac field in two special moving charts of the de Sitter spacetime is investigated pointing out the operators that commute with the Dirac one. These are the generators of the symmetry transformations corresponding to isometries that give rise to conserved quantities according to the Noether theorem. With their help the plane wave spinor solutions of the Dirac equation with given momentum and helicity are derived and the final form of the quantum Dirac field is established. It is shown that the canonical quantization leads to a correct physical interpretation of the massive or massless fermion quantum fields.Comment: 19 pages, LaTeX w AMS sym

Pragas da soja no Brasil e seu manejo integrado.

Pragas da soja; Pragas que atacam as folhas: Anticarsia gemmatalis (Lep.: Noctuidae); Pseudoplusia includens (Lep.: Noctuidae); Coleopteros desfolhadores; Outros organismos que atacam as folhas; Pragas que atacam vagens e graos: Percevejos sugadores de sementes; Lagartas das vagens; Brocas das vagens; Pragas que atacam plantulas, hastes e peciolos: Sternechus subsignatus (Col.: Curculionidae); Elasmopalpus lignosellus (Lep.: Pyralidae); Epinotia aporema (Lep.: Tortricidae); Outros insetos que atacam plantulas, hastes e peciolos; Pragas que atacam as raizes da soja: Coros; Percevejos-castanho-da-raiz; Outros insetos que atacam as raizes; Inimigos naturais das pragas da soja; Predadores: Hemipteros; Coleopteros; Parasitoides: Parasitoides de lagartas; Parasitoides de percevejos; Entomopatogenos: Virus; Fungos; Amostragem das pragas; Controle integrado e nivel de acao; Controle integrado das pragas que atacam as folhas: Anticarsia gemmatalis; Pseudoplusia includens e outros Plusiinae;; Coleopteros desfolhadores; Outros organismos que atacam as folhas; Controle integrado das pragas que atacam as vagens e graos: Percevejos; Lagarta-das-vagens; Broca-das-vagens; Controle integrado das pragas que atacam plantulas, hastes e peciolos: Sternechus subsignatus; Epinotia aporema; Controle integrado das pragas que atacam as raizes: Coros; Percevejo-castanho-da-raiz.bitstream/item/128003/1/ID-6173.pd

Probabilistic forecasts of storm sudden commencements from interplanetary shocks using machine learning

In this study we investigate the ability of several different machine learning models to provide probabilistic predictions as to whether interplanetary shocks observed upstream of the Earth at L1 will lead to immediate (Sudden Commencements, SCs) or longer lasting magnetospheric activity (Storm Sudden Commencements, SSCs). Four models are tested including linear (Logistic Regression), non‐linear (Naive Bayes and Gaussian Process) and ensemble (Random Forest) models, and are shown to provide skillful and reliable forecasts of SCs with Brier Skill Scores (BSSs) of ~ 0:3 and ROC scores > 0:8. The most powerful predictive parameter is found to be the range in the interplanetary magnetic field. The models also produce skillful forecasts of SSCs, though with less reliability than was found for SCs. The BSSs and ROC scores returned are ~0:21 and 0.82 respectively. The most important parameter for these predictions was found to be the minimum observed BZ. The simple parameterization of the shock was tested by including additional features related to magnetospheric indices and their changes during shock impact, resulting in moderate increases in reliability. Several parameters, such as velocity and density, may be able to be more accurately predicted at a longer lead time, e.g. from heliospheric imagery. When the input was limited to the velocity and density the models were found to perform well at forecasting SSCs, though with lower reliability than previously (BSSs ~ 0:16, ROC Scores ~ 0:8), Finally, the models were tested with hypothetical extreme data beyond current observations, showing dramatically different extrapolations

The quantum J_{1}-J_{1'}-J_{2} spin-1/2 Heisenberg antiferromagnet: A variational method study

The phase transition of the quantum spin-1/2 frustrated Heisenberg antiferroferromagnet on an anisotropic square lattice is studied by using a variational treatment. The model is described by the Heisenberg Hamiltonian with two antiferromagnetic interactions: nearest-neighbor (NN) with different coupling strengths J_{1} and J_{1'} along x and y directions competing with a next-nearest-neighbor coupling J_{2} (NNN). The ground state phase diagram in the ({\lambda},{\alpha}) space, where {\lambda}=J_{1'}/J_{1} and {\alpha}=J_{2}/J_{1}, is obtained. Depending on the values of {\lambda} and {\alpha}, we obtain three different states: antiferromagnetic (AF), collinear antiferromagnetic (CAF) and quantum paramagnetic (QP). For an intermediate region {\lambda}_{1}<{\lambda}<1 we observe a QP state between the ordered AF and CAF phases, which disappears for {\lambda} above some critical value {\lambda}_{1}. The boundaries between these ordered phases merge at the quantum critical endpoint (QCE). Below this QCE there is again a direct first-order transition between the AF and CAF phases, with a behavior approximately described by the classical line {\alpha}_{c}{\simeq}{\lambda}/2

Systematic effects in the extraction of the 'WMAP haze'

The extraction of a 'haze' from the WMAP microwave skymaps is based on subtraction of known foregrounds, viz. free-free (bremsstrahlung), thermal dust and synchrotron, each traced by other skymaps. While the 408 MHz all-sky survey is used for the synchrotron template, the WMAP bands are at tens of GHz where the spatial distribution of the radiating cosmic ray electrons ought to be quite different because of the energy-dependence of their diffusion in the Galaxy. The systematic uncertainty this introduces in the residual skymap is comparable to the claimed haze and can, for certain source distributions, have a very similar spectrum and latitudinal profile and even a somewhat similar morphology. Hence caution must be exercised in interpreting the 'haze' as a physical signature of, e.g., dark matter annihilation in the Galactic centre.Comment: 17 pages, 12 figures; improved diffusion model; extended discussion of spectral index maps; clarifying comments, figures and references added; to appear in JCA