469 research outputs found
Optimal prediction and the Klein-Gordon equation
The method of optimal prediction is applied to calculate the future means of
solutions to the Klein-Gordon equation. It is shown that in an appropriate
probability space, the difference between the average of all solutions that
satisfy certain constraints at time t=0, and the average computed by an
approximate method, is small with high probability.Comment: 18 page
Inverse spectral problems for Sturm-Liouville operators with singular potentials
The inverse spectral problem is solved for the class of Sturm-Liouville
operators with singular real-valued potentials from the space .
The potential is recovered via the eigenvalues and the corresponding norming
constants. The reconstruction algorithm is presented and its stability proved.
Also, the set of all possible spectral data is explicitly described and the
isospectral sets are characterized.Comment: Submitted to Inverse Problem
Vascular flow reserve as a link between long-term blood pressure level and physical performance capacity in mammals
Mean arterial pressure (MAP) is surprisingly similar across different species of mammals, and it is, in general, not known which factors determine the arterial pressure level. Mammals often have a pronounced capacity for sustained physical performance. This capacity depends on the vasculature having a flow reserve that comes into play as tissue metabolism increases. We hypothesize that microvascular properties allowing for a large vascular flow reserve is linked to the level of the arterial pressure.To study the interaction between network properties and network inlet pressure, we developed a generic and parsimonious computational model of a bifurcating microvascular network where diameter and growth of each vessel evolves in response to changes in biomechanical stresses. During a simulation, the network develops well‐defined arterial and venous vessel characteristics. A change in endothelial function producing a high precapillary resistance and thus a high vascular flow reserve is associated with an increase in network inlet pressure. Assuming that network properties are independent of body mass, and that inlet pressure of the microvascular network is a proxy for arterial pressure, the study provides a conceptual explanation of why high performing animals tend to have a high MAP
Phase Coherence and Control of Stored Photonic Information
We report the demonstration of phase coherence and control for the recently
developed "light storage" technique. Specifically, we use a pulsed magnetic
field to vary the phase of atomic spin excitations which result from the
deceleration and storing of a light pulse in warm Rb vapor. We then convert the
spin excitations back into light and detect the resultant phase shift in an
optical interferometric measurement. The coherent storage of photon states in
matter is essential for the practical realization of many basic concepts in
quantum information processing.Comment: 5 pages, 3 figures. Submitted to Phys. Rev. Let
A stationary source of non-classical or entangled atoms
A scheme for generating continuous beams of atoms in non-classical or
entangled quantum states is proposed and analyzed. For this the recently
suggested transfer technique of quantum states from light fields to collective
atomic excitation by Stimulated Raman adiabatic passage [M.Fleischhauer and
M.D. Lukin, Phys.Rev.Lett. 84, 5094 (2000)] is employed and extended to matter
waves
Storage of light in atomic vapor
We report an experiment in which a light pulse is decelerated and trapped in
a vapor of Rb atoms, stored for a controlled period of time, and then released
on demand. We accomplish this storage of light by dynamically reducing the
group velocity of the light pulse to zero, so that the coherent excitation of
the light is reversibly mapped into a collective Zeeman (spin) coherence of the
Rb vapor
Time-Local Quantum-State-Diffusion Equation for Multilevel Quantum Dynamics
An open quantum system with multiple levels coupled to a bosonic environment
at zero temperature is investigated systematically using the non-Markovian
quantum-state-diffusion (QSD) method [W. T. Strunz, L. Di\'osi, and N. Gisin,
Phys. Rev. Lett. 82, 1801 (1999)]. We have established exact time-local QSD
equations for a set of interesting multilevel open systems, including high-spin
systems, multiple-transition atomic models, and multilevel atomic models driven
by time-dependent external fields. These exact QSD equations have paved the way
to evaluate the dynamics of open multilevel atomic systems in the general
non-Markovian regimes without any approximation.Comment: 7 pages, 3 figures, 1 tabl
The impact of morphine treatment on bladder cancer cell proliferation and apoptosis: in vitro studies
Aim: The aim of this study was to determine the effect of morphine on bladder cancer cell proliferation and apoptosis in vitro. Materials and Methods: MTT assay was used to measure percentage growth of RT-112 human bladder cancer cells after 72 hours of morphine/morphine + naloxone treatment. Expression of µ-opioid receptors was assessed by Western blot and finally, apoptotic assay with CellEvent Caspase-3/7 Green Detection Reagent was carried out using confocal microscopy. Results: The MTT assays showed that morphine increased RT-112 cell growth. Naloxone inhibited this growth enhancing effect. Western blot analysis regarding µ-opioid receptor expression in RT-112 cells remains inconclusive. Morphine was also found to decrease the rate of apoptosis of RT-112 cells, an effect which naloxone inhibited. Conclusions: This study provides evidence that morphine, at clinically relevant doses, causes RT-112 bladder cancer cell proliferation, possibly opioid receptor mediated and at least some of this effect might be due to decreased apoptosis. Clinically, this suggests that in patients with bladder cancer, managing pain with morphine might have detrimental consequences on patient outcomes and alternative pain relief should be considered if possible. Key Words: bladder cancer, morphine, cell proliferation, µ-opioid receptor, apoptosis
Review of biorthogonal coupled cluster representations for electronic excitation
Single reference coupled-cluster (CC) methods for electronic excitation are
based on a biorthogonal representation (bCC) of the (shifted) Hamiltonian in
terms of excited CC states, also referred to as correlated excited (CE) states,
and an associated set of states biorthogonal to the CE states, the latter being
essentially configuration interaction (CI) configurations. The bCC
representation generates a non-hermitian secular matrix, the eigenvalues
representing excitation energies, while the corresponding spectral intensities
are to be derived from both the left and right eigenvectors. Using the
perspective of the bCC representation, a systematic and comprehensive analysis
of the excited-state CC methods is given, extending and generalizing previous
such studies. Here, the essential topics are the truncation error
characteristics and the separability properties, the latter being crucial for
designing size-consistent approximation schemes. Based on the general order
relations for the bCC secular matrix and the (left and right) eigenvector
matrices, formulas for the perturbation-theoretical (PT) order of the
truncation errors (TEO) are derived for energies, transition moments, and
property matrix elements of arbitrary excitation classes and truncation levels.
In the analysis of the separability properties of the transition moments, the
decisive role of the so-called dual ground state is revealed. Due to the use of
CE states the bCC approach can be compared to so-called intermediate state
representation (ISR) methods based exclusively on suitably orthonormalized CE
states. As the present analysis shows, the bCC approach has decisive advantages
over the conventional CI treatment, but also distinctly weaker TEO and
separability properties in comparison with a full (and hermitian) ISR method
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