6,339 research outputs found
J.S. Bell's Concept of Local Causality
John Stewart Bell's famous 1964 theorem is widely regarded as one of the most
important developments in the foundations of physics. It has even been
described as "the most profound discovery of science." Yet even as we approach
the 50th anniversary of Bell's discovery, its meaning and implications remain
controversial. Many textbooks and commentators report that Bell's theorem
refutes the possibility (suggested especially by Einstein, Podolsky, and Rosen
in 1935) of supplementing ordinary quantum theory with additional ("hidden")
variables that might restore determinism and/or some notion of an
observer-independent reality. On this view, Bell's theorem supports the
orthodox Copenhagen interpretation. Bell's own view of his theorem, however,
was quite different. He instead took the theorem as establishing an "essential
conflict" between the now well-tested empirical predictions of quantum theory
and relativistic \emph{local causality}. The goal of the present paper is, in
general, to make Bell's own views more widely known and, in particular, to
explain in detail Bell's little-known mathematical formulation of the concept
of relativistic local causality on which his theorem rests. We thus collect and
organize many of Bell's crucial statements on these topics, which are scattered
throughout his writings, into a self-contained, pedagogical discussion
including elaborations of the concepts "beable", "completeness", and
"causality" which figure in the formulation. We also show how local causality
(as formulated by Bell) can be used to derive an empirically testable Bell-type
inequality, and how it can be used to recapitulate the EPR argument.Comment: 19 pages, 4 figure
The Impact of Task- and Team-Generic Teamwork Skills Training on Team Effectiveness
This study examined the effects of training team members in three task- and teamgeneric teamwork skills: planning and task coordination, collaborative problem solving, and communication. We first examined the degree to which task- and team-generic teamwork skills training impacted team performance on a task unrelated to the content of the training program.We then examined whether the effects of task- and team-generic teamwork skills training on team performance were due to the transfer of skills directly related to planning and task coordination, collaborative problem solving, and communication. Results from 65 four-person project teams indicated that task- and team-generic teamwork skills training led to significantly higher levels of team performance. Results also indicated that the effects of task- and teamgeneric teamwork skills training on team performance were mediated by planning and task coordination and collaborative problem solving behavior. Although communication was positively affected by the task- and team-generic teamwork skills training, it did not mediate the relationship between task- and team-generic teamwork skills training and team performance.Theoretical and practical implications of these results are discussed, as well as possible limitations and directions for future research
Integrated stratigraphy of the Kimmeridge Clay Formation (Upper Jurassic) based on exposures and boreholes in south Dorset, UK
For the purposes of a high-resolution multi-disciplinary study of the Upper Jurassic Kimmeridge Clay Formation, two boreholes were drilled at Swanworth Quarry and one at Metherhills, south Dorset, UK. Together, the cores represent the first complete section through the entire formation close to the type section. We present graphic logs that record the stratigraphy of the cores, and outline the complementary geophysical and analytical data sets (gamma ray, magnetic susceptibility, total organic carbon, carbonate, [delta]13Corg). Of particular note are the new borehole data from the lowermost part of the formation which does not crop out in the type area. Detailed logs are available for download from the Kimmeridge Drilling Project web-site at http://kimmeridge.earth.ox.ac.uk/. Of further interest is a mid-eudoxus Zone positive shift in the [delta]13Corg record, a feature that is also registered in Tethyan carbonate successions, suggesting that it is a regional event and may therefore be useful for correlation. The lithostratigraphy of the cores has been precisely correlated with the nearby cliff section, which has also been examined and re-described. Magnetic-susceptibility and spectral gamma-ray measurements were made at a regular spacing through the succession, and facilitate core-to-exposure correlation. The strata of the exposure and core have been subdivided into four main mudrock lithological types: (a) medium-dark–dark-grey marl; (b) medium-dark–dark grey–greenish black shale; (c) dark-grey–olive-black laminated shale; (d) greyish-black–brownish-black mudstone. The sections also contain subordinate amounts of siltstone, limestone and dolostone. Comparison of the type section with the cores reveals slight lithological variation and notable thickness differences between the coeval strata. The proximity of the boreholes and different parts of the type section to the Purbeck–Isle of Wight Disturbance is proposed as a likely control on the thickness changes
The Newfoundland Ice Sheet Shelf (NISS) Survey – Research Cruise: Bay d’Espoir to Burgeo, Newfoundland
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