A Model of the Information Seeking and Decision Making of Online Coin Buyers

Introduction. The Everyday Life Information Seeking approach suggests that much information behaviour takes place in non-work settings, for example in the pursuit of leisure activities such as hobbies. This study focuses on a community of collectors to examine how they gather information to decide whether to purchase an item for their collection when the target item has an ambiguous or deficient description. Method. Manual scanning of eBay and other online discussion board for coin buyers led to 187 postings indicating an attempt to reach a purchase decision, or to authenticate a purchased coin, through solicitation or posting of advice. Analysis. Postings were coded as to whether they dealt with 1. Ambiguous images in a listing, 2. Ambiguous statements in a listing, 3. Information missing from a listing, or 4. Sharing of other information (not restricted to a coin listing) that might possibly be used to make a purchase decision or authentication. Results. Using the example postings and the investigator\u27s earlier experiences, a model of coin buyer decision making was created, outlining the different paths and strategies that collectors may take when faced with uncertainties. Conclusion. The Internet facilitates access to both documentary reference material, as well as human information sources. The formation of virtual communities is made possibly, alongside existing face-to-face communities of hobbyists. Further studies of collectors could benefit from comparisons of information behaviour in both virtual and actual worlds

Alien Registration- Case, Donald H. (Hodgdon, Aroostook County)

https://digitalmaine.com/alien_docs/35896/thumbnail.jp

Ariel - Volume 1 Number 1

Copyright 1969 Arie

Ariel - Volume 1 Number 3

Copyright 1969 Arie

Ariel - Volume 1 Number 2

Copyright 1969 Arie

Measurements of Compton Scattered Transition Radiation at High Lorentz Factors

X-ray transition radiation can be used to measure the Lorentz factor of relativistic particles. Standard transition radiation detectors (TRDs) typically incorporate thin plastic foil radiators and gas-filled x-ray detectors, and are sensitive up to \gamma ~ 10^4. To reach higher Lorentz factors (up to \gamma ~ 10^5), thicker, denser radiators can be used, which consequently produce x-rays of harder energies (>100 keV). At these energies, scintillator detectors are more efficient in detecting the hard x-rays, and Compton scattering of the x-rays out of the path of the particle becomes an important effect. The Compton scattering can be utilized to separate the transition radiation from the ionization background spatially. The use of conducting metal foils is predicted to yield enhanced signals compared to standard nonconducting plastic foils of the same dimensions. We have designed and built a Compton Scatter TRD optimized for high Lorentz factors and exposed it to high energy electrons at the CERN SPS. We present the results of the accelerator tests and comparisons to simulations, demonstrating 1) the effectiveness of the Compton Scatter TRD approach; 2) the performance of conducting aluminum foils; and 3) the ability of a TRD to measure energies approximately an order of magnitude higher than previously used in very high energy cosmic ray studies.X-ray transition radiation can be used to measure the Lorentz factor of relativistic particles. Standard transition radiation detectors (TRDs) typically incorporate thin plastic foil radiators and gas-filled x-ray detectors, and are sensitive up to \gamma ~ 10^4. To reach higher Lorentz factors (up to \gamma ~ 10^5), thicker, denser radiators can be used, which consequently produce x-rays of harder energies (>100 keV). At these energies, scintillator detectors are more efficient in detecting the hard x-rays, and Compton scattering of the x-rays out of the path of the particle becomes an important effect. The Compton scattering can be utilized to separate the transition radiation from the ionization background spatially. The use of conducting metal foils is predicted to yield enhanced signals compared to standard nonconducting plastic foils of the same dimensions. We have designed and built a Compton Scatter TRD optimized for high Lorentz factors and exposed it to high energy electrons at the CERN SPS. We present the results of the accelerator tests and comparisons to simulations, demonstrating 1) the effectiveness of the Compton Scatter TRD approach: 2) the performance of conducting aluminum foils: and 3) the ability of a TRD to measure energies approximately an order of magnitude higher than previously used in very high energy cosmic ray studies

Development and Performance of Detectors for the Cryogenic Dark Matter Search Experiment with an Increased Sensitivity Based on a Maximum Likelihood Analysis of Beta Contamination

The Cryogenic Dark Matter Search (CDMS) uses cryogenically-cooled detectors made of germanium and silicon in an attempt to detect dark matter in the form of Weakly-Interacting Massive Particles (WIMPs). The expected interaction rate of these particles is on the order of 1/kg/day, far below the 200/kg/day expected rate of background interactions after passive shielding and an active cosmic ray muon veto. Our detectors are instrumented to make a simultaneous measurement of both the ionization energy and thermal energy deposited by the interaction of a particle with the crystal substrate. A comparison of these two quantities allows for the rejection of a background of electromagnetically-interacting particles at a level of better than 99.9%. The dominant remaining background at a depth of {approx} 11 m below the surface comes from fast neutrons produced by cosmic ray muons interacting in the rock surrounding the experiment. Contamination of our detectors by a beta emitter can add an unknown source of unrejected background. In the energy range of interest for a WIMP study, electrons will have a short penetration depth and preferentially interact near the surface. Some of the ionization signal can be lost to the charge contacts there and a decreased ionization signal relative to the thermal signal will cause a background event which interacts at the surface to be misidentified as a signal event. We can use information about the shape of the thermal signal pulse to discriminate against these surface events. Using a subset of our calibration set which contains a large fraction of electron events, we can characterize the expected behavior of surface events and construct a cut to remove them from our candidate signal events. This thesis describes the development of the 6 detectors (4 x 250 g Ge and 2 x 100 g Si) used in the 2001-2002 CDMS data run at the Stanford Underground Facility with a total of 119 livedays of data. The preliminary results presented are based on the first use of a beta-eliminating cut based on a maximum-likelihood characterization described above

Ariel - Volume 2 Number 6

Editors Richard J. Bonanno Robin A. Edwards Associate Editors Steven Ager Stephen Flynn Shep Dickman Tom Williams Lay-out Editor Eugenia Miller Contributing Editors Michael J. Blecker W. Cherry Light James J. Nocon Lynne Porter Editors Emeritus Delvyn C. Case, Jr. Paul M. Fernhof