Interpreting Indicators of a Transfer of N from Legume to Grass in Competition Studies

The transfer of N from legume to grass in mixtures is important for regulating competition. In competition studies which include both monocultures and mixtures, N transfer should be detectable by grass N measurements but may be masked by competitive reductions in grass growth. In the study reported here, whole plant DM and N were measured in Panicum maximum var trichoglume and Neonotonia wightii grown in monocultures and additively in mixtures. While competition reduced whole grass plant DM and N in mixture relative to monoculture, higher grass shoot % N and N yield in the mixture at early harvests appeared reliable indicators of N transfer. In another experiment, monocultures and mixtures were grown in a replacement series with and without rhizobial N fixation. Higher grass shoot %N was a reflection of lower grass plant density in the mixtures. However grass shoot N yields in the mixtures consistently greater than in monoculture over at least a few harvests appeared a reliable indication of N transfer

Acousto-optic signature analysis for inspection of the orbiter thermal protection tile bonds

The goal of this research is to develop a viable NDE technique for the inspection of orbiter thermal protection system (TPS) tile bonds. Phase 2, discussed here, concentrated on developing an empirical understanding of the bonded and unbonded vibration signatures of acreage tiles. Controlled experiments in the laboratory have provided useful information on the dynamic response of TPS tiles. It has been shown that several signatures are common to all the pedigree tiles. This degree of consistency in the tile-SIP (strain isolation pad) dynamic response proves that an unbond can be detected for a known tile and establish the basis for extending the analysis capability to arbitrary tiles for which there are no historical data. The field tests of the noncontacting laser acoustic sensor system, conducted at the Kennedy Space Center (KSC), investigated the vibrational environment of the Orbiter Processing Facility (OPF) and its effect on the measurement and analysis techniques being developed. The data collected showed that for orbiter locations, such as the body flap and elevon, the data analysis scheme, and/or the sensor, will require modification to accommodate the ambient motion. Several methods were identified for accomplishing this, and a solution is seen as readily achievable. It was established that the tile response was similar to that observed in the laboratory. Of most importance, however, is that the field environment will not affect the physics of the dynamic response that is related to bond condition. All of this information is fundamental to any future design and development of a prototype system

Acousto-Optic Measurement of Micromechanical Resonance for Adhesive Bond Integrity

Traditional nondestructive evaluation (NDE) of bonding flaws has generally used either ultrasound or x-rays as a directed energy source to image or otherwise detect the discontinuity of an improper bond. While this approach has broad applicability, it is inadequate where the material is highly attenuating or anisotropic, or when it is impossible to achieve an adequate interrogation due to geometrical constraints. These difficulties are seen in materials such as the silica fiber composites used for the thermal protection tiles on the Space Shuttle Orbiter, insulating rubber liners used for solid rocket motors, and rubber or foam coating materials

Laser Detection of Acoustic Displacements by Destabilizing a Frequency Stabilized Helium Neon Laser

A sensor for detecting low-amplitude acoustic displacements is described. This instrument is based on a stabilized helium-neon laser and is capable of measuring submicron displacements of diffuse surfaces at distances of up to 10 m and with a bandwidth between 0.2 and 100 kHz. The potential for extension of the technique to higher frequencies is discussed. The sensor uses the inherent sensitivity of an alternate-mode balanced, frequency-stabilized laser to small amounts of retroreflected light. Applications of the sensor include a study of bonding flaws in complex multilayer materials, such as the thermal protection tiles on the Space Shuttle Orbiter and in graphite epoxy laminar composites

Vacation posts on Facebook:A model for incidental vicarious travel consumption

Vicarious consumption of travel is ubiquitous. However little is known about the psychological processes this initiates or the potential for resultant behaviors beyond direct steps toward patronage. We address this gap through developing and testing the incidental vicarious travel consumption model (IVTCM), which draws from well-established knowledge of the self-concept and compensatory consumption. In the context of vicariously consuming idyllic vacation posts on Facebook, the model identifies the following: individuals’ travel-related self-discrepancies may become active, leading to feelings of dejection, initiating five possible compensatory consumption behaviors (Direct, Symbolic, Dissociation, Escapism, Fluid). A sequential mixed-method design (total n=860) provides support for the IVTCM. The primary contributions of the paper are as follows: first the IVTCM can be used to understand different forms of vicarious travel consumption. Second, specific understanding on the impact of idyllic vacation posts is contributed, furthering knowledge on the role of social media within touris

How residents and interns utilise and perceive the personal digital assistant and UpToDate

<p>Abstract</p> <p>Background</p> <p>In this era of evidence-based medicine, doctors are increasingly using information technology to acquire medical knowledge. This study evaluates how residents and interns utilise and perceive the personal digital assistant (PDA) and the online resource UpToDate.</p> <p>Methods</p> <p>This is a questionnaire survey of all residents and interns in a tertiary teaching hospital.</p> <p>Results</p> <p>Out of 168 doctors, 134 (79.8%) responded to the questionnaire. Only 54 doctors (40.3%) owned a PDA. Although these owners perceived that the PDA was most useful for providing drug information, followed by medical references, scheduling and medical calculators, the majority of them did not actually have medical software applications downloaded on their PDAs. The greatest concerns highlighted for the PDA were the fear of loss and breakage, and the preference for working with desktop computers and paper. Meanwhile, only 76 doctors (56.7%) used UpToDate, even though the hospital had an institutional subscription for it. Although 93.4% of these users would recommend UpToDate to a colleague, only 57.9% stated that the use of UpToDate had led to a change in their management of patients.</p> <p>Conclusion</p> <p>Although UpToDate and various PDA software applications were deemed useful by some of the residents and interns in our study, both digital tools were under-utilised. More should be done to facilitate the use of medical software applications on PDAs, to promote awareness of tools for evidence-based medicine such as UpToDate, and to facilitate the application of evidence-based medicine in daily clinical practice.</p

Microstructural Evolution in Thin Films of Electronic Materials

Contains reports on eight research projects.National Science Foundation (Grant ECS 85-06565)U.S. Air Force - Office of Scientific Research (Contract AFOSR 85-0154)National Science Foundation-Materials Research Laboratory(Grant DMR 81-19285)National Science Foundation (Grant DMR 85-06030)International Business Machines, Inc. Faculty Development AwardMitsui Career Development AwardInternational Business Machines, Inc.Semiconductor Research Corporation (Contract 86-05-080)Joint Services Electronics Program (Contract DAAG-29-83-K-0003)Charles Stark Draper LaboratoryDefense Advanced Research Projects Agency (DARPA)Nippon Telegraph and Telephone, Inc