651 research outputs found
Black Hole Tunneling Entropy and the Spectrum of Gravity
The tunneling approach for entropy generation in quantum gravity is applied
to black holes. The area entropy is recovered and shown to count only a tiny
fraction of the black hole degeneracy. The latter stems from the extension of
the wave function outside the barrier. In fact the semi-classical analysis
leads to infinite degeneracy. Evaporating black holes leave then infinitely
degenerate "planckons" remnants which can neither decay into, nor be formed
from, ordinary matter in a finite time. Quantum gravity opens up at the Planck
scale into an infinite Hilbert space which is expected to provide the
ultraviolet cutoff required to render the theory finite in the sector of large
scale physics.Comment: 26 pages + 3 figures, phyzzx macropackage, figures available from
Author
Collapses and Avoiding Wave Function Spreading
We address the impossibility of achieving exact time reversal in a system
with many degrees of freedom. This is a particular example of the difficult
task of "aiming" an initial classical state so as to become a specific final
state. We also comment on the classical-to-quantum transition in any
non-separable closed system of degrees of freedom. Even if the
system is initially in a well defined WKB, semi-classical state, quantum
evolution and, in particular, multiple reflections at classical turning points
make it completely quantum mechanical with each particle smeared almost
uniformly over all the configuration space. The argument, which is presented in
the context of hard discs, is quite general. Finally, we briefly address
more complex quantum systems with many degrees of freedom and ask when can they
provide an appropriate environment to the above simpler systems so that quantum
spreading is avoided by continuously leaving "imprints" in the environment. We
also discuss the possible connections with the pointer systems that are needed
in the quantum-to-classical "collapse" transitions
Internet based molecular collaborative and publishing tools
The scientific electronic publishing model has hitherto been an Internet based delivery of electronic articles that are essentially replicas of their paper counterparts. They contain little in the way of added semantics that may better expose the science, assist the peer review process and facilitate follow on collaborations, even though the enabling technologies have been around for some time and are mature. This thesis will examine the evolution of chemical electronic publishing over the past 15 years. It will illustrate, which the help of two frameworks, how publishers should be exploiting technologies to improve the semantics of chemical journal articles, namely their value added features and relationships with other chemical resources on the Web.
The first framework is an early exemplar of structured and scalable electronic publishing where a Web content management system and a molecular database are integrated. It employs a test bed of articles from several RSC journals and supporting molecular coordinate and connectivity information. The value of converting 3D molecular expressions in chemical file formats, such as the MOL file, into more generic 3D graphics formats, such as Web3D, is assessed. This exemplar highlights the use of metadata management for bidirectional hyperlink maintenance in electronic publishing.
The second framework repurposes this metadata management concept into a Semantic Web application called SemanticEye. SemanticEye demonstrates how relationships between chemical electronic articles and other chemical resources are established. It adapts the successful semantic model used for digital music metadata management by popular applications such as iTunes. Globally unique identifiers enable relationships to be established between articles and other resources on the Web and SemanticEye implements two: the Document Object Identifier (DOI) for articles and the IUPAC International Chemical Identifier (InChI) for molecules. SemanticEye’s potential as a framework for seeding collaborations between researchers, who have hitherto never met, is explored using FOAF, the friend-of-a-friend Semantic Web standard for social networks
Complex case: A biofeedback intervention to control impulsiveness in a severely personality disordered forensic patient by Rick Howard, Klaus Schellhorn and John Lumsden
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98777/1/pmh1232.pd
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