12,590 research outputs found
Haemorrhage control of the pre-hospital trauma patient.
. This is an Open Access article distributed under the terms of the Creative Commons
Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http:// creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated
Liver Resections for Metastases from Intraabdominal Leiomyosarcoma
This paper discusses liver resection for intraabdominal
leiomyosarcoma metastases as a therapy for
carefully selected patients. Of the 83 hepatectomies
performed from 1992 to 1996, five were resections for
liver metastases due to intraabdominal leiomyosarcoma,
in 3 patients. The surgical indication was single
liver metastases, without any evidence of extrahepatic
disease. No mortality occurred during surgery and the
longest survival was 38 months. We concluded that
liver resection for leiomyosarcoma metastases can be
performed, allowing a long term survival in an
occasional patient
Self-aligned fabrication process for silicon quantum computer devices
We describe a fabrication process for devices with few quantum bits (qubits),
which are suitable for proof-of-principle demonstrations of silicon-based
quantum computation. The devices follow the Kane proposal to use the nuclear
spins of 31P donors in 28Si as qubits, controlled by metal surface gates and
measured using single electron transistors (SETs). The accurate registration of
31P donors to control gates and read-out SETs is achieved through the use of a
self-aligned process which incorporates electron beam patterning, ion
implantation and triple-angle shadow-mask metal evaporation
Applications of BGP-reflection functors: isomorphisms of cluster algebras
Given a symmetrizable generalized Cartan matrix , for any index , one
can define an automorphism associated with of the field of rational functions of independent indeterminates It is an isomorphism between two cluster algebras associated to the
matrix (see section 4 for precise meaning). When is of finite type,
these isomorphisms behave nicely, they are compatible with the BGP-reflection
functors of cluster categories defined in [Z1, Z2] if we identify the
indecomposable objects in the categories with cluster variables of the
corresponding cluster algebras, and they are also compatible with the
"truncated simple reflections" defined in [FZ2, FZ3]. Using the construction of
preprojective or preinjective modules of hereditary algebras by Dlab-Ringel
[DR] and the Coxeter automorphisms (i.e., a product of these isomorphisms), we
construct infinitely many cluster variables for cluster algebras of infinite
type and all cluster variables for finite types.Comment: revised versio
Energy diffusion in strongly driven quantum chaotic systems
The energy evolution of a quantum chaotic system under the perturbation that
harmonically depends on time is studied for the case of large perturbation, in
which the rate of transition calculated from the Fermi golden rule exceeds the
frequency of perturbation. It is shown that the energy evolution retains its
diffusive character, with the diffusion coefficient that is asymptotically
proportional to the magnitude of perturbation and to the square root of the
density of states. The results are supported by numerical calculation. They
imply the absence of the quantum-classical correspondence for the energy
diffusion and the energy absorption in the classical limit .Comment: 12 pages, 3 figures, RevTe
Entropy and information in neural spike trains: Progress on the sampling problem
The major problem in information theoretic analysis of neural responses and
other biological data is the reliable estimation of entropy--like quantities
from small samples. We apply a recently introduced Bayesian entropy estimator
to synthetic data inspired by experiments, and to real experimental spike
trains. The estimator performs admirably even very deep in the undersampled
regime, where other techniques fail. This opens new possibilities for the
information theoretic analysis of experiments, and may be of general interest
as an example of learning from limited data.Comment: 7 pages, 4 figures; referee suggested changes, accepted versio
Bandgap Change of Carbon Nanotubes: Effect of Small Tensile and Torsional Strain
We use a simple picture based on the electron approximation to study
the bandgap variation of carbon nanotubes with uniaxial and torsional strain.
We find (i) that the magnitude of slope of bandgap versus strain has an almost
universal behaviour that depends on the chiral angle, (ii) that the sign of
slope depends on the value of and (iii) a novel change in sign
of the slope of bandgap versus uniaxial strain arising from a change in the
value of the quantum number corresponding to the minimum bandgap. Four orbital
calculations are also presented to show that the orbital results are
valid.Comment: Revised. Method explained in detai
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