15,158 research outputs found
Observational issues in radiometric and interferometric detection and analysis of the Sunyaev-Zel'dovich effects
This review discusses the techniques used in single-dish and interferometric
radiometric observations of the Sunyaev-Zel'dovich effects, the pitfalls that
arise, the systematic and other sources of error in the data, and the
uncertainties in the interpretation of the results.Comment: 46 pages, 23 figures. To appear in Background Microwave Radiation and
Intracluster Cosmology, Proceedings of the International School of Physics
"Enrico Fermi", Eds. Melchiorri, F. & Rephaeli, Y., 200
Electroweak measurements from hadron machines
The hadron collider experiments continue to make significant contributions to electroweak physics which complement those from e /sup +/e/sup -/ machines. The higher cross sections and square root s allow some unique measurements to be made e.g the mass of the top quark. The precision of many measurements is comparable to, if not better than, that achieved at e/sup +/e/sup -/ machines. All results - top mass, W mass, W width, branching fractions, sin/sup 2/ theta /sub W/, cross sections etc. are in excellent agreement with the Standard Model in a range of processes: qq, eq, nu q over a wide span in Q/sup 2/. The future is bright and significant new results are expected from the Tevatron and HERA experiments before the LHC. (21 refs)
Measurement of the Average Time-Integrated Mixing Probability of b-Flavored Hadrons Produced at the Tevatron
Micromachined Millimetre-Wave Passive Components at 38 and 77 GHz
A precision micro-fabrication technique has been developed for millimetre-wave components of air-filled three-dimensional structures, such as rectangular coaxial lines or waveguides. The devices are formed by bonding several layers of micromachining defined slices with a thickness of a few hundred micrometres. The slices are thickphotoresist SU8 defined by photolithography, or silicon with a pattern defined by deep reactive ion etching; both are coated with gold by evaporation. The process is simple, and low-cost, as compared with conventional precision metal machining, but yields mm-wave components with good performance. The components are light weight and truly airfilled with no dielectric support. This paper reviews several of these micromachined mm-wave components at 38 and 77 GHz for communications and radar applications
Quantitative ultraviolet measurements on wetted thin-layer chromatography plates using a charge-coupled device camera
This paper presents the first study of the UV imaging of spots on thin-layer chromatographic plates whilst still wet with solvent. Imaging of spots of benzophenone during and after development was carried out using a charge-coupled device camera. Limits of detection were found to be 5 ng on a wetted plate and 3 ng for a dry plate and the relationship between peak area and sample loading was found to be linear in the low nanograrn range over an order of magnitude for both wet and dry modes with r(2) values > 0.99. It was found that UV measurements on wet glass-backed plates suffer from low sensitivity; however, the use of aluminium-backed plates gave increased sensitivity. The apparent absorption coefficient (epsilon(app)) of 10AU m(2) g(-1) at 254 nm is consistent with reflection of the light from the aluminium surface with a double pass through the sorbent layer, and suggests that use of aluminium-backed plates should enable monitoring of separations by UV absorbance during TLC development. (c) 2008 Elsevier B.V. All rights reserved
Lean and Six Sigma in Hospitality Organizations: Benefits, Challenges, and Implementation
Purpose:
The purpose of this paper to provide a plan and framework to successfully implement Lean and Six Sigma into a hospitality organization
Shaped nozzles for cryogenic buffer gas beam sources
Cryogenic buffer gas beams are important sources of cold molecules. In this
work we explore the use of a converging-diverging nozzle with a buffer-gas
beam. We find that, under appropriate circumstances, the use of a nozzle can
produce a beam with improved collimation, lower transverse temperatures, and
higher fluxes per solid angle
Effects of Mosquito Control Chemicals on Aquatic Fauna
No mosquito abatement districts have ever been organized in Arkansas. Mosquito control efforts have been largely adulticiding operations by either aerial application or ground thermal fogging machines. Practically no chemical applications have been directed at the larval stage in residual water in ditches and depressions from which adult populations arise. Some larviciding with ethyl parathion has been done in ricefields. Although the treatment is very effective in mosquito reduction, voluntary treatment has not been completely successful. Because relatively little insecticide has been used as a larvicide in Arkansas, it was possible to evaluate the effect of recommended larvicides on non-target organisms in the aquatic environment. A developing mosquito control demonstration program in the rice-producing area provided the study site
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