745 research outputs found
Aspectos biológicos de Dalbulus maidis (DeLong & Wolcott) (Hemiptera: Cicadellidae) em hibridos de milho (Zea mays L.).
Alguns aspectos da biologia da cigarrinha do milho, Dalbulus maidis (DeLong & Wolcott), foram estudados em seis híbridos de milho contrastantes quanto à resistência a esse inseto, selecionados em ensaios conduzidos no campo. O experimento foi realizado em casa de vegetação a 26,0 ±4,9°C e 78,8±6,8% de UR. Utilizando-se microgaiolas, dez ninfas por híbrido foram diariamente observadas, anotando-se o número de ínstares e o período de desenvolvimento. Nos adultos obtidos mediram-se o comprimento do corpo, a largura do abdome e a distância entre os olhos compostos. Entre os híbridos avaliados, somente o Pioneer 3027 prolongou significativamente o período de desenvolvimento das ninfas, em cerca de três dias. Não houve diferença significativa entre os híbridos quanto ao número de ínstares e tamanho do corpo dos adultos
CdSe-single-nanoparticle based active tips for near-field optical microscopy
We present a method to realize active optical tips for use in near-field
optics that can operate at room temperature. A metal-coated optical tip is
covered with a thin polymer layer stained with CdSe nanocrystals or nanorods at
low density. The time analysis of the emission rate and emission spectra of the
active tips reveal that a very small number of particles - possibly down to
only one - can be made active at the tip apex. This opens the way to near-field
optics with a single inorganic nanoparticle as a light source
Detection of a Large Arc of Ionized Hydrogen Far Above the Cas OB6 Association: A Superbubble Blowout into the Galactic Halo?
The Wisconsin H-Alpha Mapper (WHAM) Northern Sky Survey has revealed a loop
of H II reaching 1300 pc from the Galactic midplane above the Cas OB6
association in the Perseus sprial arm. This enormous feature surrounds and
extends far above the "W4 Chimney" identified by Normandeau et al. and appears
to be associated with the star formation activity near the W3/W4/W5 H II region
complex. The existence of this ionized structure suggests that past episodes of
massive star formation have cleared the H I from an enormous volume above the
Perseus arm, allowing Lyman continuum photons from O stars near the Galactic
midplane to reach into the halo.Comment: 12 pages, 2 figures, accepted for publication in ApJ (Letters
Scientific Performance of the ISDC Quick Look Analysis
The INTEGRAL Science Data Centre (ISDC) routinely monitors the Near Real Time
data (NRT) from the INTEGRAL satellite. A first scientific analysis is made in
order to check for the detection of new, transient or highly variable sources
in the data. Of primary importance for this work is the Interactive Quick Look
Analysis (IQLA), which produces JEM-X and ISGRI images and monitors them for
interesting astrophysical eventsComment: 4 pages, 3 figures. Proceedings of 5th INTEGRAL Workshop: The
INTEGRAL Universe, Munich, 16-20 February 2004. Accepted for publication in
European Space Agency Special Publication 552. See paper for institute
affiliation
Antimicrobial Activity of Chitosan Membranes Against Staphylococcus Aureus of Clinical Origin
Healthy human skin has beneficial microflora and many pathogens causing infections. Staphylococcus aureus is the most prevalent and can have multiresistance to antibiotics. Chitosan is a polysaccharide composed of glucosamine and N-acetyl-D-glucosamine, which is biodegradable and has antimicrobial activity. As part of a national scientific research project for the development and application of biomaterials, we decided to study the effect of different membranes based on chitosan against strains of S. aureus isolated from infected ulcers. The study found that seven of nine strains of S. aureus are sensitive to rifampin and the least eight of nine strains were multiresistant to more than ten antibiotics. All chitosan-based membranes confirm its antimicrobial effect on direct contact with an increase in its diameter. The contact area of the membranes is increased according to the concentration of chitosan. The highest average area increase was the chitosan membranes with honey and glycerin, 88.32%. Chitosan membranes have shown their effectiveness against S. aureus strains of clinical origin. Thus, these materials can be applied for the treatment of chronic ulcers without toxic hazards and resistance caused by antibiotics
- …