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

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

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

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

Susceptibility testing of Candida albicans and Candida glabrata to Glycyrrhiza glabra L.

Medicinal plants and their botanical formulations have gained a pivotal attention among scientific researchers mainly due to its action as health promoters. Licorice (Glycyrrhiza glabra L.) constitutes a great example, with an increasingly evidenced antimicrobial potential. Opportunistic yeast infections constitute an alarming public health problem, highly exacerbated by the inefficacy of antifungal drugs and the increase of drug-resistant microorganisms, being Candida species one of the most common invaders. The present work aims to assess Candida glabrata and Candida albicans susceptibility to G. glabra methanol: water extract by using flow cytometry and transmission electron microscopy techniques. After 5 minutes, licorice extract (1.5 mg/mL) altered Candida membrane potential. Within an hour, it induced primary damages on Candida species cells, causing cell cytoplasm disorganization with high evidence of cell membrane invaginations, making cells turgid. Thus, based on the current findings, licorice extract seems to be a promising anti-Candida agent, without presenting any toxic potential at the effective concentrations used.The authors are grateful to Foundation for Science and Technology (FCT, Portugal) for N. Martins grant (SFRH/BD/87658/2012) and financial support to the research centre CIMO (strategic project PEst-OE/ AGR/UI0690/2014). This work was also supported by the Programa Operacional, Fatores de competitividade – COMPETE and by national funds through FCT – Fundação para a Ciência e a Tecnologia on the scope of the projects FCT PTDC/SAU-MIC/119069/2010, RECI/EBBEBI/0179/2012 and PEst-OE/EQB/LA0023/2013. The authors thank the Project “BioHealth – Biotechnology and Bioengineering approaches to improve health quality”, Ref. NORTE-07-0124-FEDER-000027, cofunded by the Programa Operacional Regional do Norte (ON.2–O Novo Norte), QREN, FEDER.info:eu-repo/semantics/publishedVersio

Tidal Dwarf Galaxies at Intermediate Redshifts

We present the first attempt at measuring the production rate of tidal dwarf galaxies (TDGs) and estimating their contribution to the overall dwarf population. Using HST/ACS deep imaging data from GOODS and GEMS surveys in conjunction with photometric redshifts from COMBO-17 survey, we performed a morphological analysis for a sample of merging/interacting galaxies in the Extended Chandra Deep Field South and identified tidal dwarf candidates in the rest-frame optical bands. We estimated a production rate about 1.4 {\times} 10^{-5} per Gyr per comoving volume for long-lived TDGs with stellar mass 3 {\times} 10^{8-9} solar mass at 0.5<z<1.1. Together with galaxy merger rates and TDG survival rate from the literature, our results suggest that only a marginal fraction (less than 10%) of dwarf galaxies in the local universe could be tidally-originated. TDGs in our sample are on average bluer than their host galaxies in the optical. Stellar population modelling of optical to near-infrared spectral energy distributions (SEDs) for two TDGs favors a burst component with age 400/200 Myr and stellar mass 40%/26% of the total, indicating that a young stellar population newly formed in TDGs. This is consistent with the episodic star formation histories found for nearby TDGs.Comment: 9 pages, 5 figures, Accepted for publication in Astrophysics & Space Scienc

Alpha-decay branching ratios of near-threshold states in 19Ne and the astrophysical rate of 15O(alpha,gamma)19Ne

The 15O(alpha,gamma)19Ne reaction is one of two routes for breakout from the hot CNO cycles into the rp process in accreting neutron stars. Its astrophysical rate depends critically on the decay properties of excited states in 19Ne lying just above the 15O + alpha threshold. We have measured the alpha-decay branching ratios for these states using the p(21Ne,t)19Ne reaction at 43 MeV/u. Combining our measurements with previous determinations of the radiative widths of these states, we conclude that no significant breakout from the hot CNO cycle into the rp process in novae is possible via 15O(alpha,gamma)19Ne, assuming current models accurately represent their temperature and density conditions

Measurement of the ttbar Production Cross Section in ppbar Collisions at sqrt(s)=1.96 TeV using Lepton + Jets Events with Lifetime b-tagging

We present a measurement of the top quark pair ($t\bar{t}$) production cross section ($\sigma_{t\bar{t}}$) in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV using 230 pb$^{-1}$ of data collected by the D0 experiment at the Fermilab Tevatron Collider. We select events with one charged lepton (electron or muon), missing transverse energy, and jets in the final state. We employ lifetime-based b-jet identification techniques to further enhance the $t\bar{t}$ purity of the selected sample. For a top quark mass of 175 GeV, we measure $\sigma_{t\bar{t}}=8.6^{+1.6}_{-1.5}(stat.+syst.)\pm 0.6(lumi.)$ pb, in agreement with the standard model expectation.Comment: 7 pages, 2 figures, 3 tables Submitted to Phys.Rev.Let

BB flavour tagging using charm decays at the LHCb experiment

An algorithm is described for tagging the flavour content at production of neutral $B$ mesons in the LHCb experiment. The algorithm exploits the correlation of the flavour of a $B$ meson with the charge of a reconstructed secondary charm hadron from the decay of the other $b$ hadron produced in the proton-proton collision. Charm hadron candidates are identified in a number of fully or partially reconstructed Cabibbo-favoured decay modes. The algorithm is calibrated on the self-tagged decay modes $B^+ \to J/\psi \, K^+$ and $B^0 \to J/\psi \, K^{*0}$ using $3.0\mathrm{\,fb}^{-1}$ of data collected by the LHCb experiment at $pp$ centre-of-mass energies of $7\mathrm{\,TeV}$ and $8\mathrm{\,TeV}$. Its tagging power on these samples of $B \to J/\psi \, X$ decays is $(0.30 \pm 0.01 \pm 0.01) \%$.Comment: All figures and tables, along with any supplementary material and additional information, are available at http://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-027.htm