933 research outputs found
Mineral reconnaissance at the Highland boundary with special reference to the Loch Lomond and Aberfoyle areas
Serpentinite bodies at the Highland Boundary in
the Loch Lomond and Aberfoyle areas are
extensively altered to magnesite-quartz and
ferroan-dolomite-quartz rocks. Silicification was
probably initiated before conversion to carbonate.
Relict textures indicate that the serpentinites were
derived from peridotitic precursors, but one
unaltered ultrabasic sample comprises mainly
chromian diopside. Chromite geochemistry and
hornblende-schist mineralogy rein force the ophiolitic
character of the serpentinite-spilite-blackshale-
chcrt assemblage of the Highland Border.
Magnetic and VLF traverses across the Highland
Boundary fracture-zone near Helensburgh
identified several anomalous zones. One may be
due to a concealed serpentinitic sheet.
The most mineralised serpentinite body
showed chromium values in the range 1000 to
3035 ppm. Such concentrations arc not encouraging
for the small serpentinites at Loch Lomond
and Aberfoyle, but may be significant regarding
larger serpentinites elsewhere at the Highland
Border
Correlation of mechanical factors and gallbladder pain
Acalculous biliary pain occurs in patients with no gallstones, but is similar to that experienced by patients with gallstones. Surgical removal of the gallbladder (GB) in these patients is only successful in providing relief of symptoms to about half of those operated on, so a reliable pain-prediction model is needed. In this paper, a mechanical model is developed for the human biliary system during the emptying phase, based on a clinical test in which GB volume changes are measured in response to a standard stimulus and a recorded pain profile. The model can describe the bile emptying behaviour, the flow resistance in the biliary ducts, the peak total stress, including the passive and active stresses experienced by the GB during emptying. This model is used to explore the potential link between GB pain and mechanical factors. It is found that the peak total normal stress may be used as an effective pain indicator for GB pain. When this model is applied to clinical data of volume changes due to Cholecystokinin stimulation and pain from 37 patients, it shows a promising success rate of 88.2% in positive pain prediction
Investigation of stratiform sulphide mineralisation at Meall Mor, South Knapdale, Argyll
A co-ordinated geochemical-geophysical-geological investigation of copper
mineralisation in the Meal1 ?46r area, South Knapdale, Argyll was carried 0th
in 1976 and followed by a drilling programme of 3 shallow holes in early 1977.
The mineralisation occursin a zone of weak stratiform sulphide mineralisation
(the pyrite zone) with a strike length of 1Okm in the Upper &ins Quartz&e
of the Middle Dalradian.
The geochemical drainage survey showed the existence of a strongly anomalous
distribution of Cu and Sb in the Abhainn Srathain draining south from .
Meal1 M&- and detailed soil sampling over the pyrite zone outlined a broad
area enriched in copper. Deeper soil sampling confirmed the anomalously
high copper values and a coincident IP anomaly was found stretching from
Meal1 M& south to the old mine workings on Abhainn Srathain, and is probably
caused by a local enrichment of pyrite and chalcopyrite within the pyrite
zone.
Three boreholes were drilled; two on coincident geochemical and geophysical
anomalies, and the third beneath the old mines at Abhainn Srathain. Copper
values in the first two holes range up to 0.24% Cu over 4.27m, but up to
1.06% Cu over 2.67m in the third and this enrichment may be related to a
later remobilisation of the disseminated chalcopyrite. The results of subsequent
drilling at two other sites are given in Appendix III
New Insights into Uniformly Accelerated Detector in a Quantum Field
We obtained an exact solution for a uniformly accelerated Unruh-DeWitt
detector interacting with a massless scalar field in (3+1) dimensions which
enables us to study the entire evolution of the total system, from the initial
transient to late-time steady state. We find that the Unruh effect as derived
from time-dependent perturbation theory is valid only in the transient stage
and is totally invalid for cases with proper acceleration smaller than the
damping constant. We also found that, unlike in (1+1)D results, the (3+1)D
uniformly accelerated Unruh-DeWitt detector in a steady state does emit a
positive radiated power of quantum nature at late-times, but it is not
connected to the thermal radiance experienced by the detector in the Unruh
effect proper.Comment: 6 pages, invited talk given by SYL at the conference of International
Association for Relativistic Dynamics (IARD), June 2006, Storrs, Connecticut,
US
The Triple Symbiotic System CH Cygni
Analysis of high-resolution IR spectra of CH Cygni shows that the star is a triple system with a short period orbit of just over 2 yrs. The period ratio of seven for CH Cyg is the smallest known for a triple system. The symbiotic pair is the short-period system. An eccentric and a circular orbit solution are determined for the short-period pair, and the circular orbit solution is found to be more appropriate. The observed eccentricity appears to be due to phase-dependent line asymmetries resulting from the irradiation of the M giant by the white dwarf. The system does not eclipse. The most consistent mode of the system is a short-period pair consisting of an M6 giant of two solar masses that is within a factor of two of filling its Roche lobe and a white dwarf of 0.2 solar mass. The orbital inclination is about 70 deg. The unseen third star in the system is probably a G-K dwarf
Fragility of a class of highly entangled states of many quantum-bits
We consider a Quantum Computer with n quantum-bits (`qubits'), where each
qubit is coupled independently to an environment affecting the state in a
dephasing or depolarizing way. For mixed states we suggest a quantification for
the property of showing {\it quantum} uncertainty on the macroscopic level. We
illustrate in which sense a large parameter can be seen as an indicator for
large entanglement and give hypersurfaces enclosing the set of separable
states. Using methods of the classical theory of maximum likelihood estimation
we prove that this parameter is decreasing with 1/\sqrt{n} for all those states
which have been exposed to the environment.
Furthermore we consider a Quantum Computer with perfect 1-qubit gates and
2-qubit gates with depolarizing error and show that any state which can be
obtained from a separable initial state lies inbetween a family of pairs of
certain hypersurfaces parallel to those enclosing the separable ones.Comment: 9 Pages, RevTe
Entangled Electronic States in Multiple Quantum-Dot Systems
We present an analytically solvable model of colinear, two-dimensional
quantum dots, each containing two electrons. Inter-dot coupling via the
electron-electron interaction gives rise to sets of entangled ground states.
These ground states have crystal-like inter-plane correlations and arise
discontinously with increasing magnetic field. Their ranges and stabilities are
found to depend on dot size ratios, and to increase with .Comment: To appear in Physical Review B (in press). RevTeX file. Figures
available from [email protected]
Uniformly Accelerated Charge in a Quantum Field: From Radiation Reaction to Unruh Effect
We present a stochastic theory for the nonequilibrium dynamics of charges
moving in a quantum scalar field based on the worldline influence functional
and the close-time-path (CTP or in-in) coarse-grained effective action method.
We summarize (1) the steps leading to a derivation of a modified
Abraham-Lorentz-Dirac equation whose solutions describe a causal semiclassical
theory free of runaway solutions and without pre-acceleration patholigies, and
(2) the transformation to a stochastic effective action which generates
Abraham-Lorentz-Dirac-Langevin equations depicting the fluctuations of a
particle's worldline around its semiclassical trajectory. We point out the
misconceptions in trying to directly relate radiation reaction to vacuum
fluctuations, and discuss how, in the framework that we have developed, an
array of phenomena, from classical radiation and radiation reaction to the
Unruh effect, are interrelated to each other as manifestations at the
classical, stochastic and quantum levels. Using this method we give a
derivation of the Unruh effect for the spacetime worldline coordinates of an
accelerating charge. Our stochastic particle-field model, which was inspired by
earlier work in cosmological backreaction, can be used as an analog to the
black hole backreaction problem describing the stochastic dynamics of a black
hole event horizon.Comment: Invited talk given by BLH at the International Assembly on
Relativistic Dynamics (IARD), June 2004, Saas Fee, Switzerland. 19 pages, 1
figur
Spin-Orbit Effects in the Excitation of Proton and Neutron States in the (p,p') Reaction at 160 MeV, 120 MeV, and 95 MeV
Supported by the National Science Foundation and Indiana Universit
Nanofabrication by magnetic focusing of supersonic beams
We present a new method for nanoscale atom lithography. We propose the use of
a supersonic atomic beam, which provides an extremely high-brightness and cold
source of fast atoms. The atoms are to be focused onto a substrate using a thin
magnetic film, into which apertures with widths on the order of 100 nm have
been etched. Focused spot sizes near or below 10 nm, with focal lengths on the
order of 10 microns, are predicted. This scheme is applicable both to precision
patterning of surfaces with metastable atomic beams and to direct deposition of
material.Comment: 4 pages, 3 figure
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