1,624 research outputs found
Importance Sampling for multi-constraints rare event probability
Improving Importance Sampling estimators for rare event probabilities
requires sharp approx- imations of the optimal density leading to a nearly
zero-variance estimator. This paper presents a new way to handle the estimation
of the probability of a rare event defined as a finite intersection of subset.
We provide a sharp approximation of the density of long runs of a random walk
condi- tioned by multiples constraints, each of them defined by an average of a
function of its summands as their number tends to infinity.Comment: Conference pape
Can job insecurity be managed? Evaluating an organizational-level intervention addressing the negative effects of restructuring
Although downsizing and reorganisation are recognised as serious threats to the psychological well-being of employees, intervention strategies for addressing these events are limited. This study evaluated the effects of a participatory organisational-level intervention in which employees and managers chose to address the psychosocial consequences, specifically job insecurity, of restructuring. The intervention was conducted among postal service letter carriers in Denmark and was evaluated based on quantitative and qualitative data. Using interviews (N = 24) and observations, the programme theory of the intervention and to what extent the intervention had been implemented were assessed. Using survey data (N = 238), repeated measures ANOVAs were conducted to test for differences in the development of job insecurity between the intervention group and a comparison group. The results indicate that the intervention group had a significantly smaller increase in one dimension of job insecurity as compared to the comparison group. Therefore, we conclude that employees’ experiencing of job insecurity, which typically follows in the wake of restructuring, can be addressed by planned efforts at the workplace level
Disentanglement by Dissipative Open System Dynamics
This paper investigates disentanglement as a result of evolution according to
a class of master equations which include dissipation and interparticle
interactions. Generalizing an earlier result of Di\'{o}si, the time taken for
complete disentanglement is calculated (i.e. for disentanglement from any other
system). The dynamics of two harmonically coupled oscillators is solved in
order to study the competing effects of environmental noise and interparticle
coupling on disentanglement. An argument based on separability conditions for
gaussian states is used to arrive at a set of conditions on the couplings
sufficient for all initial states to disentangle for good after a finite time.Comment: Paper in conjunction with and following on from P.J. Dodd and J.J.
Halliwell: quant-ph/031206
Centre for the Study of Islam and Christian-Muslim Relations
The CSIC was founded in 1976 as a central teaching department of the federation of Selly Oak Colleges. Its roots lay in a lectureship by the Edward Cadbury Charitable Trust (ECCT) in the 1930s, when Dr Alphonse Mingana was the first incumbent. With Cadbury family support he had been able to collect a large amount of Arabic and Syriac manuscripts still housed today in the library at Selly Oak. Dr Mingana started a tradition of text-based study of Islam and Christian-Muslim relations which was notably continued by Dr John Sweetman in his magisterial work on Islam and Christian Theology
Congestive heart failure in rats is associated with increased expression and targeting of aquaporin-2 water channel in collecting duct
We tested whether severe congestive heart
failure (CHF), a condition associated with excess free-water retention, is accompanied by altered regulation of the vasopressin-regulated water channel, aquaporin-2 (AQP2), in the renal collecting duct. CHF was induced by left coronary artery ligation. Compared with sham-operated animals, rats with CHF had severe heart failure with elevated left ventricular end-diastolic pressures (LVEDP): 26.9 ± 3.4 vs. 4.1 ± 0.3 mmHg, and reduced plasma sodium concentrations (142.2 ± 1.6 vs. 149.1 ± 1.1 mEq/liter). Quantitative immunoblotting of total kidney membrane fractions revealed a significant increase in AQP2 expression in animals with CHF (267 ± 53%, n=12) relative to sham-operated controls (100 ± 13%, n=14). In contrast, immunoblotting demonstrated a lack of an increase in expression of AQP1 and AQP3 water channel
expression, indicating that the effect on AQP2 was selective.Furthermore, postinfarction animals without LVEDP elevation or plasma Na reduction showed no increase in AQP2 expression (121 ± 28% of sham levels, n=6). Immunocytochemistry and immunoelectron microscopy demonstrated very abundant labeling of the apical plasma membrane and relatively little labeling of intracellular vesicles in collecting duct cells from rats with severe CHF, consistent with enhanced trafficking of AQP2 to the apical plasma membrane. The selective increase in AQP2 expression and enhanced plasma membrane targeting provide an explanation for the development of water retention and hyponatremia in severe
CHF
Characterization of Binary Constraint System Games
We consider a class of nonlocal games that are related to binary constraint
systems (BCSs) in a manner similar to the games implicit in the work of Mermin
[N.D. Mermin, "Simple unified form for the major no-hidden-variables theorems,"
Phys. Rev. Lett., 65(27):3373-3376, 1990], but generalized to n binary
variables and m constraints. We show that, whenever there is a perfect
entangled protocol for such a game, there exists a set of binary observables
with commutations and products similar to those exhibited by Mermin. We also
show how to derive upper bounds strictly below 1 for the the maximum entangled
success probability of some BCS games. These results are partial progress
towards a larger project to determine the computational complexity of deciding
whether a given instance of a BCS game admits a perfect entangled strategy or
not.Comment: Revised version corrects an error in the previous version of the
proof of Theorem 1 that arises in the case of POVM measurement
Non-local Realistic Theories and the Scope of the Bell Theorem
According to a widespread view, the Bell theorem establishes the untenability
of so-called 'local realism'. On the basis of this view, recent proposals by
Leggett, Zeilinger and others have been developed according to which it can be
proved that even some non-local realistic theories have to be ruled out. As a
consequence, within this view the Bell theorem allows one to establish that no
reasonable form of realism, be it local or non-local, can be made compatible
with the (experimentally tested) predictions of quantum mechanics. In the
present paper it is argued that the Bell theorem has demonstrably nothing to do
with the 'realism' as defined by these authors and that, as a consequence,
their conclusions about the foundational significance of the Bell theorem are
unjustified.Comment: Forthcoming in Foundations of Physic
Addressing the clumsiness loophole in a Leggett-Garg test of macrorealism
The rise of quantum information theory has lent new relevance to experimental
tests for non-classicality, particularly in controversial cases such as
adiabatic quantum computing superconducting circuits. The Leggett-Garg
inequality is a "Bell inequality in time" designed to indicate whether a single
quantum system behaves in a macrorealistic fashion. Unfortunately, a violation
of the inequality can only show that the system is either (i)
non-macrorealistic or (ii) macrorealistic but subjected to a measurement
technique that happens to disturb the system. The "clumsiness" loophole (ii)
provides reliable refuge for the stubborn macrorealist, who can invoke it to
brand recent experimental and theoretical work on the Leggett-Garg test
inconclusive. Here, we present a revised Leggett-Garg protocol that permits one
to conclude that a system is either (i) non-macrorealistic or (ii)
macrorealistic but with the property that two seemingly non-invasive
measurements can somehow collude and strongly disturb the system. By providing
an explicit check of the invasiveness of the measurements, the protocol
replaces the clumsiness loophole with a significantly smaller "collusion"
loophole.Comment: 7 pages, 3 figure
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