2,276 research outputs found
Weak Pion Production off the Nucleon
We develop a model for the weak pion production off the nucleon, which
besides the Delta pole mechanism (weak excitation of the
resonance and its subsequent decay into ), includes also some background
terms required by chiral symmetry. We re-fit the form factor to
the flux averaged ANL differential cross
section data, finding a substantially smaller contribution of the Delta pole
mechanism than traditionally assumed in the literature. Within this scheme, we
calculate several differential and integrated cross sections, including pion
angular distributions, induced by neutrinos and antineutrinos and driven both
by charged and neutral currents. In all cases we find that the background terms
produce quite significant effects and that they lead to an overall improved
description of the data, as compared to the case where only the Delta pole
mechanism is considered. We also show that the interference between the Delta
pole and the background terms produces parity-violating contributions to the
pion angular differential cross section, which are intimately linked to odd
correlations in the contraction between the leptonic and hadronic tensors.
However, these latter correlations do not imply a genuine violation of time
reversal invariance because of the existence of strong final state interaction
effects.Comment: Typos corrected; comments adde
Development and validation of an automated thawing and mixing workcell
Journal ArticleWorking toward a goal of total laboratory automation, we are automating manual activities in our highest volume laboratory section. Because half of all specimens arriving in this laboratory section are frozen, we began by developing an automated workcell for thawing frozen specimens and mixing the thawed specimens to remove concentration gradients resulting from freezing and thawing
The influence of certain fungi on the sporulation of Melanospora destruens shear and of some other ascomycetes
This article does not have an abstract
Low back pain and psychosocial factors are not predictive of future pain impact in hip and knee osteoarthritis
Visual Earth observation performance in the space environment. Human performance measurement 4: Flight experiments
A wide variety of secondary payloads have flown on the Space Transportation System (STS) since its first flight in the 1980's. These experiments have typically addressed specific issues unique to the zero-gravity environment. Additionally, the experiments use the experience and skills of the mission and payload specialist crew members to facilitate data collection and ensure successful completion. This paper presents the results of the Terra Scout experiment, which flew aboard STS-44 in November 1991. This unique Earth Observation experiment specifically required a career imagery analyst to operate the Spaceborne Direct-View Optical System (SpaDVOS), a folded optical path telescope system designed to mount inside the shuttle on the overhead aft flight deck windows. Binoculars and a small telescope were used as backup optics. Using his imagery background, coupled with extensive target and equipment training, the payload specialist was tasked with documenting the following: (1) the utility of the equipment; (2) his ability to acquire and track ground targets; (3) the level of detail he could discern; (4) the atmospheric conditions; and (5) other in-situ elements which contributed to or detracted from his ability to analyze targets. Special emphasis was placed on the utility of a manned platform for research and development of future spaceborne sensors. The results and lessons learned from Terra Scout will be addressed including human performance and equipment design issues
Editorial: “Weighing in” on the Framingham Osteoarthritis Study: Measuring Biomechanical and Metabolic Contributions to Osteoarthritis
How to Block Cartel Formation and Price-Fixing
Abstract written by the AEI-Brookings Joint Center: Allowing foreign buyers of goods produced by international cartels to pursue civil antitrust damages in U.S. courts would better deter cartel formation and price-fixing than do sanctions currently imposed by global criminal and civil justice systems.Technology and Industry, Regulatory Reform, Other Topics
Properties and applications of precision oligomer materials; where organic and polymer chemistry join forces
Abstract Precise oligomeric materials constitute a growing area of research with implications for various applications as well as fundamental studies. Notably, this field of science which can be termed macro-organic chemistry, draws inspiration from both traditional polymer chemistry and organic synthesis, combining the molecular precision of organic chemistry with the materials properties of macromolecules. Discrete oligomers enable access to unprecedented materials properties, for example, in self-assembled structures, crystallization, or optical properties. The degree of control over oligomer structures resembles many biological systems and enables the design of materials with tailored properties and the development of fundamental structure–property relationships. This Review highlights recent developments in macro-organic chemistry from synthetic concepts to materials properties, with a focus on self-assembly and molecular recognition. Finally, an outlook for future research directions is provided
Measuring patient perceptions about osteoporosis pharmacotherapy
Abstract
Background
Adherence to osteoporosis pharmacotherapy is poor, and linked with patient perceptions of the benefits of, and barriers to taking these treatments. To better understand the association between patient perceptions and osteoporosis pharmacotherapy, we generated thirteen items that may tap into patient perceptions about the benefits of, and barriers to osteoporosis treatment; and included these items as part of a standardized telephone interview of women aged 65–90 years (n = 871). The purpose of this paper is to report the psychometric evaluation of our scale.
Findings
Upon detailed analysis, six of the thirteen items were omitted: four redundant, one did not correlate well with any other item and one factorial complex. From the remaining seven items, two distinct unidimensional domains emerged (variance explained = 78%). Internal consistency of the 5-item osteoporosis drug treatment benefits domain was good (Cronbach's alpha = 0.88), and was supported by construct validity; women reporting a physician-diagnosis or taking osteoporosis pharmacotherapy had higher osteoporosis treatment benefit scores compared to those reporting no osteoporosis diagnosis or treatment respectively. Because only two items were identified as tapping into treatment barriers, we recommend they each be used as a separate item assessing potential barriers to adherence to osteoporosis pharmacotherapy, rather than combined into a single scale.
Conclusion
The 5-item osteoporosis drug treatment benefits scale may be useful to examine perceptions about the benefits of osteoporosis pharmacotherapy. Further research is needed to develop scales that adequately measure perceived barriers to osteoporosis pharmacotherapy
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