69 research outputs found
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http://tartu.ester.ee/record=b2655511~S1*es
Quark Flavor Tagging in Polarized Hadronic Processes
We describe a general approach to quark flavor tagging in polarized hadronic
processes, with particular emphasis on semi-inclusive deep inelastic
scattering. A formalism is introduced that allows one to relate chosen quark
flavor polarizations to an arbitrary combination of final-state hadron spin
asymmetries. Within the context of the presented formalism, we quantify the
sensitivity of various semi-inclusive hadron asymmetries to the light quark
flavors. We show that unpolarized Lambda's may allow one to measure strange
quark and antiquark polarizations independently. We also highlight several
applications of our formalism, particularly to measurements intended to probe
further the spin structure of the nucleon.Comment: 5 pages, 2 EPS figures (new), version to be published in PRD (Rapid
Communication
Elastic scattering with weakly bound projectiles
Possible effects of the break-up channel on the elastic scattering threshold anomaly has been investigated. We used the weakly bound 6,7Li nuclei, which is known to undergo break-up, as projectiles in order to study the elastic scattering on a 27Al target. In this contribution we present preliminary results of these experiments, which were analyzed in terms of the Optical Model and compared with other elastic scattering data using weakly bound nuclei as projectile. © 2007 American Institute of Physics.Fil:Figueira, J.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Fernández Niello, J.O. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Arazi, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Capurro, O.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Martí, G.V. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Pacheco, A.J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
Precision Determination of the Neutron Spin Structure Function g1n
We report on a precision measurement of the neutron spin structure function
using deep inelastic scattering of polarized electrons by polarized
^3He. For the kinematic range 0.014<x<0.7 and 1 (GeV/c)^2< Q^2< 17 (GeV/c)^2,
we obtain at an average . We find relatively large negative
values for at low . The results call into question the usual Regge
theory method for extrapolating to x=0 to find the full neutron integral
, needed for testing quark-parton model and QCD sum rules.Comment: 5 pages, 3 figures To be published in Phys. Rev. Let
Generalization Mediates Sensitivity to Complex Odor Features in the Honeybee
Animals use odors as signals for mate, kin, and food recognition, a strategy which appears ubiquitous and successful despite the high intrinsic variability of naturally-occurring odor quantities. Stimulus generalization, or the ability to decide that two objects, though readily distinguishable, are similar enough to afford the same consequence [1], could help animals adjust to variation in odor signals without losing sensitivity to key inter-stimulus differences. The present study was designed to investigate whether an animal's ability to generalize learned associations to novel odors can be influenced by the nature of the associated outcome. We use a classical conditioning paradigm for studying olfactory learning in honeybees [2] to show that honeybees conditioned on either a fixed- or variable-proportion binary odor mixture generalize learned responses to novel proportions of the same mixture even when inter-odor differences are substantial. We also show that the resulting olfactory generalization gradients depend critically on both the nature of the stimulus-reward paradigm and the intrinsic variability of the conditioned stimulus. The reward dependency we observe must be cognitive rather than perceptual in nature, and we argue that outcome-dependent generalization is necessary for maintaining sensitivity to inter-odor differences in complex olfactory scenes
An interdisciplinary team communication framework and its application to healthcare 'e-teams' systems design
<p>Abstract</p> <p>Background</p> <p>There are few studies that examine the processes that interdisciplinary teams engage in and how we can design health information systems (HIS) to support those team processes. This was an exploratory study with two purposes: (1) To develop a framework for interdisciplinary team communication based on structures, processes and outcomes that were identified as having occurred during weekly team meetings. (2) To use the framework to guide 'e-teams' HIS design to support interdisciplinary team meeting communication.</p> <p>Methods</p> <p>An ethnographic approach was used to collect data on two interdisciplinary teams. Qualitative content analysis was used to analyze the data according to structures, processes and outcomes.</p> <p>Results</p> <p>We present details for team meta-concepts of structures, processes and outcomes and the concepts and sub concepts within each meta-concept. We also provide an exploratory framework for interdisciplinary team communication and describe how the framework can guide HIS design to support 'e-teams'.</p> <p>Conclusion</p> <p>The structures, processes and outcomes that describe interdisciplinary teams are complex and often occur in a non-linear fashion. Electronic data support, process facilitation and team video conferencing are three HIS tools that can enhance team function.</p
XRD and Materials Analysis
This chapter summarizes the ways in which the technique of X‐ray diffraction can be used in the study of ancient material artifacts, including ceramics, metals, pigments, glass, and other objects. It discusses how XRD can be used to characterize their mineralogical composition, interpret their raw materials, provenance, and manufacturing technology, and study their degradation
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