3,221 research outputs found
The Library of Babel
We show that heavy pure states of gravity can appear to be mixed states to
almost all probes. Our arguments are made for Schwarzschild black
holes using the field theory dual to string theory in such spacetimes. Our
results follow from applying information theoretic notions to field theory
operators capable of describing very heavy states in gravity. For certain
supersymmetric states of the theory, our account is exact: the microstates are
described in gravity by a spacetime ``foam'', the precise details of which are
invisible to almost all probes.Comment: 7 pages, 1 figure, Essay receiving honorable mention in the 2005
Gravity Research Foundation essay competitio
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Implant Prophylaxis: The Next Best Practice Toward Asepsis in Spine Surgery.
Study designA literature review.ObjectivesAn evaluation of the contaminants prevalent on implants used for surgery and the aseptic methods being employed against them.MethodsPubMed was searched for articles published between 2000 and 2017 for studies evaluating the contaminants present on spine implants, and associated pre- and intraoperative implant processing and handling methodology suggested to avoid them. Systematic reviews, observational studies, bench-top studies, and expert opinions were included.ResultsEleven studies were identified whose major focus was the asepsis of implants to reduce the incidence of surgical site infection incidences during surgery. These studies measured the colony forming units of bacteria on sterilized implants and/or gloves from the surgeon, scrub nurse, and assistants, as well as reductions of surgical site infection rates in spine surgery due to changes in implant handling techniques. Additionally, the search included assessments of endotoxins and carbohydrates present on reprocessed implants. The suggested changes to surgical practice based on these studies included handling implants with only fresh gloves, keeping implants covered until the immediate time of use, reducing operating room traffic, avoiding reprocessing of implants (ie, providing terminally sterilized implants), and avoiding touching the implants altogether.ConclusionsBoth reprocessing (preoperative) and handling (intraoperative) of implants seem to lead to contamination of sterilized implants. Using a terminally sterilized device may mitigate reprocessing (preoperative implant prophylaxis), whereas the use of fresh gloves for handling each implant and/or a permanent shielding technique (intraoperative implant prophylaxis) could potentially avoid recontamination at the theatre
Coulomb Interactions and Nanoscale Electronic Inhomogeneities in Manganites
We address the issue of endemic electronic inhomogeneities in manganites
using extensive simulations on a new model with Coulomb interactions amongst
two electronic fluids, one localized (polaronic), the other extended
(band-like), and dopant ions. The long range Coulomb interactions frustrate
phase separation induced by the strong on site repulsion between the fluids. A
single quantum phase ensues which is intrinsically and strongly inhomogeneous
at a nano-scale, but homogeneous on meso-scales, with many characteristics
(including colossal responses)that agree with experiments. This, we argue, is
the origin of nanoscale inhomogeneities in manganites, rather than phase
competition and disorder related effects as often proposed.Comment: 4 pages, 3 figure
An RF-Driven Josephson Bifurcation Amplifier for Quantum Measurements
We have constructed a new type of amplifier whose primary purpose is the
readout of superconducting quantum bits. It is based on the transition of an
RF-driven Josephson junction between two distinct oscillation states near a
dynamical bifurcation point. The main advantages of this new amplifier are
speed, high-sensitivity, low back-action, and the absence of on-chip
dissipation. Pulsed microwave reflection measurements on nanofabricated Al
junctions show that actual devices attain the performance predicted by theory.Comment: 5 Figure
Tropical Grassland Ecosystems and Climate Change
Grasses are unique group of flowering plants that form the foundation for the trophic structure in terrestrial communities. The grasses are found in every conceivable habitat where plants can thrive – from sea to deserts and from wetlands to peaks of highest mountains. The grasses form a distinct biome – a major ecological formation in the global classification of vegetation
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