Using mosaic crystals for the generation of intense X-ray beams

The parametric X-ray (PXR) yield due to 500-MeV electrons in a 2-mm-thick diamond crystal with a mosaicity angle of ~0.2 mrad has been studied. It is shown that the mosaic crystal structure leads to a significant (about fourfold) increase in the PXR yield doe to the contribution of diffracted bremsstrahlung radiationye

Jet Energy Density in Hadron-Hadron Collisions at High Energies

The average particle multiplicity density dN/deta is the dynamical quantity which reflects some regularities of particle production in low-pT range. The quantity is an important ingredient of z-scaling. Experimental results on charged particle density are available for pp, pA and AA collisions while experimental properties of the jet density are still an open question. The goal of this work is to find the variable which will reflect the main features of the jet production in low transverse energy range and play the role of the scale factor for the scaling function psi(z) and variable z in data z-presentation. The appropriate candidate is the variable we called "scaled jet energy density". Scaled jet energy density is the probability to have a jet with defined ET in defined xT and pseudorapidity regions. The PYTHIA6.2 Monte Carlo generator is used for calculation of scaled jet energy density in proton-proton collisions over a high energy range (sqrt s = 200-14000 GeV) and at eta = 0. The properties of the new variable are discussed and sensitivity to "physical scenarios" applied in the standard Monte Carlo generator is noted. The results of scaled jet energy density at LHC energies are presented and compared with predictions based on z-scaling.Comment: 11 pages, LaTeX, 8 figures, Presented at the XVII International Baldin Seminar on High Energy Physics Problems "Relativistic Nuclear Physics & Quantum Chromodynamics", Dubna, Russia, September 27 - October 2, 200

Higher Order Polarizabilities of the Proton

Compton scattering results are used to probe proton structure via measurement of higher order polarizabilities. Values for $\alpha_{E2}^p,\beta_{E2}^p,\alpha_{E\nu}^p,$ $\beta_{E\nu}^p$ determined via dispersion relations are compared to predictions based upon chiral symmetry and from the constituent quark model. Extensions to spin-polarizabilities are also discussed.Comment: 18 pages, revised version with one reference adde

Fixed-t subtracted dispersion relations for Compton scattering off the nucleon

We present fixed-$t$ subtracted dispersion relations for Compton scattering off the nucleon at energies $E_\gamma \leq$ 500 MeV, as a formalism to extract the nucleon polarizabilities with a minimum of model dependence. The subtracted dispersion integrals are mainly saturated by $\pi N$ intermediate states in the $s$-channel $\gamma N \to \pi N \to \gamma N$ and $\pi \pi$ intermediate states in the $t$-channel $\gamma \gamma \to \pi \pi \to N \bar N$. For the subprocess $\gamma \gamma \to \pi \pi$, we construct a unitarized amplitude and find a good description of the available data. We show results for Compton scattering using the subtracted dispersion relations and display the sensitivity on the scalar polarizability difference $\alpha - \beta$ and the backward spin polarizability $\gamma_\pi$, which enter directly as fit parameters in the present formalism

Fungal model systems and the elucidation of pathogenicity determinants

Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.Peer reviewedPublisher PD

Resistance of Soybean Genotypes to Anticarsia gemmatalis (Lepidoptera: Erebidae): Antixenosis and Antibiosis Characterization

Injury by herbivores is a major biotic stress that limits soybean [Glycine max (L.) Merrill] crop production. Among the main soybean insect pests, Anticarsia gemmatalis Hübner is responsible for causing significant economic damage in soybean. The primary management strategy for this insect is chemical control and use of Bt transgenic soybean. Alternative strategies, such as host plant resistance, are considered an efficient and less-aggressive method, especially in association with other strategies as part of an integrated pest management (IPM) approach. In this study, we evaluated 30 soybean genotypes to verify antixenosis expression through oviposition, attractiveness, and food consumption tests. From this, we selected 13 promising genotypes to verify the possible presence of antibiosis. Our results suggest that antixenosis was found in genotypes ‘TMG 133’ RR, ‘TMG 1179’ RR, ‘IAC 19’, ‘IAC 17’, ‘IAC 100’, D75-10169, and IAC 78-2318. By influence on behavior and negative impact on larval viability, antixenosis and antibiosis were indicated for the genotypes IAC 74-2832, ‘IAC 19’, ‘IAC 17’, ‘IAC 100’, and PI 274454. ‘TMG 7062’ IPRO was found to provide antibiosis resistance by negatively affecting larval development and viability. Because of reduced food consumption by larvae, antixenosis was indicated for ‘IAC 24’. These genotypes should be considered in soybean breeding programs focusing on soybean resistance to A. gemmatalis

Time and orientation long-distance correlations between extensive air showers detected by the MRPC telescopes of the EEE Project

A search for long-distance correlations between Extensive Air Showers (EAS) detected by pairs of MRPC telescopes of the Extreme Energy Events (EEE) network was carried out. A dataset obtained by all possible pairings between ten EEE cluster sites (hosting at least two telescopes) with an overall exposure of 3968 days was analyzed. A few candidate events with unusually small time difference and angular distance were observed

Medium effects in high energy heavy-ion collisions

The change of hadron properties in dense matter based on various theoretical approaches are reviewed. Incorporating these medium effects in the relativistic transport model, which treats consistently the change of hadron masses and energies in dense matter via the scalar and vector fields, heavy-ion collisions at energies available from SIS/GSI, AGS/BNL, and SPS/CERN are studied. This model is seen to provide satisfactory explanations for the observed enhancement of kaon, antikaon, and antiproton yields as well as soft pions in the transverse direction from the SIS experiments. In the AGS heavy-ion experiments, it can account for the enhanced $K^+/\pi^+$ ratio, the difference in the slope parameters of the $K^+$ and $K^-$ transverse kinetic energy spectra, and the lower apparent temperature of antiprotons than that of protons. This model also provides possible explanations for the observed enhancement of low-mass dileptons, phi mesons, and antilambdas in heavy-ion collisions at SPS energies. Furthermore, the change of hadron properties in hot dense matter leads to new signatures of the quark-gluon plasma to hadronic matter transition in future ultrarelativistic heavy-ion collisions at RHIC/BNL.Comment: RevTeX, 65 pages, including 25 postscript figures, invited topical review for Journal of Physics G: Nuclear and Particle Physic

External marking and behavior of early instar \u3ci\u3eHelicoverpa armigera\u3c/i\u3e (Lepidoptera: Noctuidae) on soybean

Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is a pest of major agricultural crops, such as soybean and cotton. A better understanding of larval movement is important for its integrated management and resistance management. Studies with neonates through second instar larvae are still limited by the difficulties involving the handling and observation of these instars. Many studies require marking larvae, and most research involving marking is focused on moths. However, our study investigated aspects of larval behavior of the second instar of H. armigera on soybean plants. The dyes luminous powder red and Sudan Red 7B were tested as external larval markers. Both dyes successfully marked the larvae for most of 1 stadium (48 h) without deleterious effects, and are useful for short-period behavioral studies. Luminous powder red was selected for the H. armigera larval behavior study on soybean because of ease of detection during both day and night. Second instar on-plant movement was consistent, independent of the d period (morning, afternoon, evening). In general, larvae established their feeding site within a few hours of release, and remained feeding on soybean leaves. Second instar behavior suggests that management by nocturnal insecticide application, based on H. armigera larval movement, would not have an advantage over daytime application. Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) está entre as principais pragas de importancia para culturas agrícolas, como soja e algodão. Compreender o comportamento larval desta espécie, principalmente durante os estádios iniciais é de suma importância para seu manejo integrado e para o manejo de populações resistentes. No entanto, pesquisas com neonatas ou lagartas de segundo ínstar são limitadas devido às dificuldades envolvendo o manuseio e observação de insetos tão diminutos. Muitos desses estudos requerem a marcação de indivíduos, e até o momento, a maioria das pesquisas com marcação de insetos é focada em adultos. Assim, nosso estudo investigou aspectos do comportamento de lagartas de segundo instar de H. armigera em plantas de soja. Estudos prévios também foram realizados com o intuito de se avaliar métodos alternativos e eficazes para marcação de estádios iniciais das larvas desse noctuídeo e suas aplicações em estudos de comportamento. Para tanto, os corantes luminous powder (azul e vermelho) e Sudan (azul e vermelho 7B) foram testados por meio da incorporação em dieta artifical e polvilhamento sobre as lagartas. Baseado em nossos ensaios prévios de laboratório, os corantes incorporados na dieta artifical apresentaram efeitos variáveis sobre os parâmetros biológicos de H. armigera e baixa persistência após o segundo ínstar. Os corantes aplicados por polvilhamento marcaram com sucesso as lagartas e luminous powder vermelho foi selecionado para o estudo de comportamento de lagartas de segundo ínstar em plantas de soja. Lagartas de segundo ínstar apresentaram comportamento de movimento nas plantas semelhantes, independentemente do período de avaliação (manhã, tarde e noite). Em geral, a maioria das lagartas estabeleceram seu sítio de alimentação após algumas horas e permaneceram se alimentando sobre as folhas de soja. Os resultados de comportamento de larvas de H. armigera em segundo instar, documentado no presente trabalho, indicam que aplicacões noturnas de insecticidas não representa vantagem para aumento da eficiência de controle, quando comparado com aplicacões de inseticidas durante o dia