4,844 research outputs found
Charged Black Hole in a Canonical Ensemble
We consider the thermodynamics of a charged black hole enclosed in a cavity.
The charge in the cavity and the temperature at the walls are fixed so that we
have a canonical ensemble. We derive the phase structure and stability of black
hole equilibrium states. We compare our results to that of other work which
uses asymptotically anti-de Sitter boundary conditions to define the
thermodynamics. The thermodynamic properties have extensive similarities which
suggest that the idea of AdS holography is more dependent on the existence of
the boundary than on the exact details of asymptotically AdS metrics.Comment: 9 pages; 4 multipart figure
Topics on urban planning annotated bibliography
Urban planning and development - bibliography and abstract
A Quantum Adiabatic Evolution Algorithm Applied to Random Instances of an NP-Complete Problem
A quantum system will stay near its instantaneous ground state if the
Hamiltonian that governs its evolution varies slowly enough. This quantum
adiabatic behavior is the basis of a new class of algorithms for quantum
computing. We test one such algorithm by applying it to randomly generated,
hard, instances of an NP-complete problem. For the small examples that we can
simulate, the quantum adiabatic algorithm works well, and provides evidence
that quantum computers (if large ones can be built) may be able to outperform
ordinary computers on hard sets of instances of NP-complete problems.Comment: 15 pages, 6 figures, email correspondence to [email protected] ; a
shorter version of this article appeared in the April 20, 2001 issue of
Science; see http://www.sciencemag.org/cgi/content/full/292/5516/47
Distribution of an Exotic Pest, \u3ci\u3eAgromyza Frontella\u3c/i\u3e (Diptera: Agromyzidae), in Manitoba, Canada.
Agromyza frontella is an exotic alfalfa pest from Europe that was first detected in North America in 1968 and has since spread westward into Ontario and the north central United States. Informal surveys had detected A. frontella in Manitoba, but its distribution throughout this province was unknown. In 1998 we collected alfalfa stems to detect plant damage and sweep samples to detect adult A. frontella and the parasitoid Dacnusa dryas throughout the alfalfa growing region of Manitoba. In south central Manitoba, 100% of stems were damaged by A. frontella, and\u3e 100 adults/10 sweeps were recorded at several sites. In west central Manitoba, no plants were damaged and \u3c 10 adults/10 sweeps were observed. We believe this region to be near the western edge of A. frontella distribution. The most important introduced parasitoid of A. frontella, D. dryas, was not detected which suggests that D. dryas has not invaded Manitoba
Memory and superposition in a spin glass
Non-equilibrium dynamics in a Ag(Mn) spin glass are investigated by
measurements of the temperature dependence of the remanent magnetisation. Using
specific cooling protocols before recording the thermo- or isothermal remanent
magnetisations on re-heating, it is found that the measured curves effectively
disclose non-equilibrium spin glass characteristics such as ageing and memory
phenomena as well as an extended validity of the superposition principle for
the relaxation. The usefulness of this "simple" dc-method is discussed, as well
as its applicability to other disordered magnetic systems.Comment: REVTeX style; 8 pages, 4 figure
Expanding the Learning Network: How Teachers Use Pinterest
This exploratory qualitative study of 117 teachers explores how educators engage with Pinterest, an online social networking site, specifically asking: (1) What similarities and differences exist in how elementary-level preservice and elementary-level in-service teachers engage with Pinterest? (2) What similarities and differences exist in how secondary-level in-service teachers and elementary-level in-service teachers engage with Pinterest? Findings indicate teachers at all levels tend to use Pinterest to search for educational resources and adapt resources to suit their classroom needs. Preservice teachers identify a more complex interaction with Pinterest than in-service teachers when determining quality resources. Findings indicate a need for future research into teacher education practices and the complex interactions preservice teachers engage in with Pinterest resources
Isohemagglutinins of Graft Origin after ABO-Unmatched Liver Transplantation
THE increasing success of liver transplantation in recent years has provided an experimental model to study and document the hepatic synthesis of many plasma proteins.12345 The normal hepatobiliary tract has not been regarded as a major source of antibody,6,7 aside from the enteric IgA secreted from plasma into the biliary tree.8 Liver transplantation affords the opportunity to study the production of antibody to red cells. Recipient ABO incompatibility to the donor (a mismatched transplant, e.g., a group A liver transplanted into a group B recipient), although not absolutely contraindicated in liver transplantation, is avoided when possible. However, ABO-unmatched transplants (defined. © 1984, Massachusetts Medical Society. All rights reserved
Betamethasone in prevention of postoperative nausea and vomiting following breast surgery.
To investigate whether betamethasone decreases the incidence of postoperative nausea/vomiting (PONV) and reduces postoperative pain following partial mastectomy
- …