124 research outputs found
Strain Localisation, Fracturing and Hydrothermal Mineralisation: Numerical Models of the Mount Isa Copper Deposit, Australia
There is substantial need in mineral
exploration to understand the structural
controls on ore deposition for these
types of deposits in order to predict
the localities of new ones. Application
of basic principles of rock mechanics,
and numerical simulations of deformation
and fluid flow processes provide
fundamental insights to Proterozoic hydrothermal
mineralization atMount Isa,
Australia. The rheology of layered
meta-sedimentary rocks, and the orientation
and position of these layered
rocks relative to major fault systems
were the key controls on ore deposition...conferenc
Formation of Porous ZnO Nanosystems for Potential Use in Sensor Electronics
The semiconducting ZnO is a very promising material for applications in UV light emitters, optical de-tectors, solar cells, piezoelectric transducers, transparent electronics, gas sensors etc. It is known that physical properties, and as a result areas of applications, are strongly determined by morphology and size of the material’s structural elements. Therefore, the development of a technology that allows formation of nanoporous metal oxide structures with a high surface to volume ratio is of great interest nowadays. The aim of this work was to develop technology for selective formation of porous ZnO nanosystems and to de-termine the relationship between morphological characteristics of the layers obtained and their optical and electrical sensor properties with the aim of potential applications in optoelectronics and sensor electronics.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3519
Formation of Porous ZnO Nanosystems for Potential Use in Sensor Electronics
The semiconducting ZnO is a very promising material for applications in UV light emitters, optical de-tectors, solar cells, piezoelectric transducers, transparent electronics, gas sensors etc. It is known that physical properties, and as a result areas of applications, are strongly determined by morphology and size of the material’s structural elements. Therefore, the development of a technology that allows formation of nanoporous metal oxide structures with a high surface to volume ratio is of great interest nowadays. The aim of this work was to develop technology for selective formation of porous ZnO nanosystems and to de-termine the relationship between morphological characteristics of the layers obtained and their optical and electrical sensor properties with the aim of potential applications in optoelectronics and sensor electronics.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3519
A Path Integral Approach To Noncommutative Superspace
A path integral formula for the associative star-product of two superfields
is proposed. It is a generalization of the Kontsevich-Cattaneo-Felder's formula
for the star-product of functions of bosonic coordinates. The associativity of
the star-product imposes certain conditions on the background of our sigma
model. For generic background the action is not supersymmetric. The
supersymmetry invariance of the action constrains the background and leads to a
simple formula for the star-product.Comment: Latex 13 pages. v2: references and footnotes adde
A Potential Diagnostic Approach for Foetal Long-QT Syndrome, Developed and Validated in Children
Developmen
The quantum dynamic capacity formula of a quantum channel
The dynamic capacity theorem characterizes the reliable communication rates
of a quantum channel when combined with the noiseless resources of classical
communication, quantum communication, and entanglement. In prior work, we
proved the converse part of this theorem by making contact with many previous
results in the quantum Shannon theory literature. In this work, we prove the
theorem with an "ab initio" approach, using only the most basic tools in the
quantum information theorist's toolkit: the Alicki-Fannes' inequality, the
chain rule for quantum mutual information, elementary properties of quantum
entropy, and the quantum data processing inequality. The result is a simplified
proof of the theorem that should be more accessible to those unfamiliar with
the quantum Shannon theory literature. We also demonstrate that the "quantum
dynamic capacity formula" characterizes the Pareto optimal trade-off surface
for the full dynamic capacity region. Additivity of this formula simplifies the
computation of the trade-off surface, and we prove that its additivity holds
for the quantum Hadamard channels and the quantum erasure channel. We then
determine exact expressions for and plot the dynamic capacity region of the
quantum dephasing channel, an example from the Hadamard class, and the quantum
erasure channel.Comment: 24 pages, 3 figures; v2 has improved structure and minor corrections;
v3 has correction regarding the optimizatio
Perfect state distinguishability and computational speedups with postselected closed timelike curves
Bennett and Schumacher's postselected quantum teleportation is a model of
closed timelike curves (CTCs) that leads to results physically different from
Deutsch's model. We show that even a single qubit passing through a
postselected CTC (P-CTC) is sufficient to do any postselected quantum
measurement, and we discuss an important difference between "Deutschian" CTCs
(D-CTCs) and P-CTCs in which the future existence of a P-CTC might affect the
present outcome of an experiment. Then, based on a suggestion of Bennett and
Smith, we explicitly show how a party assisted by P-CTCs can distinguish a set
of linearly independent quantum states, and we prove that it is not possible
for such a party to distinguish a set of linearly dependent states. The power
of P-CTCs is thus weaker than that of D-CTCs because the Holevo bound still
applies to circuits using them regardless of their ability to conspire in
violating the uncertainty principle. We then discuss how different notions of a
quantum mixture that are indistinguishable in linear quantum mechanics lead to
dramatically differing conclusions in a nonlinear quantum mechanics involving
P-CTCs. Finally, we give explicit circuit constructions that can efficiently
factor integers, efficiently solve any decision problem in the intersection of
NP and coNP, and probabilistically solve any decision problem in NP. These
circuits accomplish these tasks with just one qubit traveling back in time, and
they exploit the ability of postselected closed timelike curves to create
grandfather paradoxes for invalid answers.Comment: 15 pages, 4 figures; Foundations of Physics (2011
Star products made (somewhat) easier
We develop an approach to the deformation quantization on the real plane with
an arbitrary Poisson structure which based on Weyl symmetrically ordered
operator products. By using a polydifferential representation for deformed
coordinates we are able to formulate a simple and effective
iterative procedure which allowed us to calculate the fourth order star product
(and may be extended to the fifth order at the expense of tedious but otherwise
straightforward calculations). Modulo some cohomology issues which we do not
consider here, the method gives an explicit and physics-friendly description of
the star products.Comment: 20 pages, v2, v3: comments and references adde
Diagnostic accuracy of the response to the brief tachycardia provoked by standing in children suspected for long QT syndrome
BACKGROUND Adult long QT syndrome (LQTS) patients have inadequate corrected QT interval (QTc) shortening and an abnormal T-wave response to the sudden heart rate acceleration provoked by standing. In adults, this knowledge can be used to aid an LQTS diagnosis and, possibly, for risk stratification. However, data on the diagnostic value of the standing test in children are currently limited. OBJECTIVE To determine the potential value of the standing test to aid LQTS diagnostics in children. METHODS In a prospective cohort including children (= 490 ms after standing only slightly increased sensitivity (91%, 95% confidence interval [CI]: 80%-98%) and slightly decreased specificity (58%, 95% CI: 47%-70%). Sensitivity increased slightly more when T-wave abnormalities were present (94%, 95% CI: 82%-99%; specificity 53%, 95% CI: 42%-65%). When a baseline QTc >= 440 ms was accompanied by a QTc >= 490 ms and T-wave abnormalities after standing, sensitivity further increased (96%, 95% CI: 85%-99%) at the expense of a further specificity decrease (41%, 95% CI: 30%-52%). Beat-to-beat analysis showed that 30 seconds after standing, LQTS children had a greater increase in heart rate compared to controls, which was more evidently present in LQTS boys and LQTS type 1 children. CONCLUSION In children, the standing test has limited additive diagnostic value for LQTS over a baseline electrocardiogram, while T-wave abnormalities after standing also have limited additional value. The standing test for LQTS should only be used with caution in children.Developmen
Sequential, successive, and simultaneous decoders for entanglement-assisted classical communication
Bennett et al. showed that allowing shared entanglement between a sender and
receiver before communication begins dramatically simplifies the theory of
quantum channels, and these results suggest that it would be worthwhile to
study other scenarios for entanglement-assisted classical communication. In
this vein, the present paper makes several contributions to the theory of
entanglement-assisted classical communication. First, we rephrase the
Giovannetti-Lloyd-Maccone sequential decoding argument as a more general
"packing lemma" and show that it gives an alternate way of achieving the
entanglement-assisted classical capacity. Next, we show that a similar
sequential decoder can achieve the Hsieh-Devetak-Winter region for
entanglement-assisted classical communication over a multiple access channel.
Third, we prove the existence of a quantum simultaneous decoder for
entanglement-assisted classical communication over a multiple access channel
with two senders. This result implies a solution of the quantum simultaneous
decoding conjecture for unassisted classical communication over quantum
multiple access channels with two senders, but the three-sender case still
remains open (Sen recently and independently solved this unassisted two-sender
case with a different technique). We then leverage this result to recover the
known regions for unassisted and assisted quantum communication over a quantum
multiple access channel, though our proof exploits a coherent quantum
simultaneous decoder. Finally, we determine an achievable rate region for
communication over an entanglement-assisted bosonic multiple access channel and
compare it with the Yen-Shapiro outer bound for unassisted communication over
the same channel.Comment: 33 pages, 2 figures; v2 contains a proof of the quantum simultaneous
decoding conjecture for two-sender quantum multiple access channels; v3 shows
how to recover the known unassisted and assisted quantum communication
regions with a coherent quantum simultaneous decode
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