15,706 research outputs found
Prevalence, Reasons for Use, and Risk Perception of Electronic Cigarettes among Post-Acute Coronary Syndrome Smokers
Purpose—The use of electronic cigarettes (e-cigarettes) has risen dramatically in recent years. However, there is currently no published data on use of e-cigarettes among cardiac patients. The current study reports on the prevalence, reasons for use, and perceived risks of e-cigarettes among post-Acute Coronary Syndrome (ACS) patients. The relationship between e-cigarette use and post- ACS tobacco smoking cessation is also explored.
Methods—Participants were drawn from a randomized trial of smoking cessation treatments following hospitalization for ACS. The current study focuses on 49 participants that completed e- cigarette questions at 24 weeks post-ACS.
Results—51.0% of participants reported ever use of an e-cigarette and 26.5% reported using an e-cigarette at some time during the 24 weeks post-ACS. Ever use and post-ACS use were both significantly associated with lower rates of abstinence from tobacco cigarettes. Participants
perceived e-cigarettes as less harmful to cardiac health than tobacco use and Chantix, and similarly harmful as nicotine replacement therapy. Participant perceived likelihood of experiencing a heart attack in the next year was 34.6% if they were to regularly use e-cigarettes only, significantly lower than perceived risk of recurrence if they were to regularly smoke only tobacco cigarettes (56.2%) and significantly higher than perceived risk of recurrence if they were to use no nicotine (15.2%).
Conclusions—A significant minority of patients are using e-cigarettes post-ACS. Providers should be prepared to discuss potential discrepancies between patient beliefs about the safety of e- cigarettes and the current state of the science
Localized quantum walks as secured quantum memory
We show that a quantum walk process can be used to construct and secure
quantum memory. More precisely, we show that a localized quantum walk with
temporal disorder can be engineered to store the information of a single,
unknown qubit on a compact position space and faithfully recover it on demand.
Since the localization occurss with a finite spread in position space, the
stored information of the qubit will be naturally secured from the simple
eavesdropper. Our protocol can be adopted to any quantum system for which
experimental control over quantum walk dynamics can be achieved.Comment: 7 pages, 4 figure
Assembly Bias and Splashback in Galaxy Clusters
We use publicly available data for the Millennium Simulation to explore the
implications of the recent detection of assembly bias and splashback signatures
in a large sample of galaxy clusters. These were identified in the SDSS/DR8
photometric data by the redMaPPer algorithm and split into high- and
low-concentration subsamples based on the projected positions of cluster
members. We use simplified versions of these procedures to build cluster
samples of similar size from the simulation data. These match the observed
samples quite well and show similar assembly bias and splashback signals.
Previous theoretical work has found the logarithmic slope of halo density
profiles to have a well-defined minimum whose depth decreases and whose radius
increases with halo concentration. Projected profiles for the observed and
simulated cluster samples show trends with concentration which are opposite to
these predictions. In addition, for high-concentration clusters the minimum
slope occurs at significantly smaller radius than predicted. We show that these
discrepancies all reflect confusion between splashback features and features
imposed on the profiles by the cluster identification and concentration
estimation procedures. The strong apparent assembly bias is not reflected in
the three-dimensional distribution of matter around clusters. Rather it is a
consequence of the preferential contamination of low-concentration clusters by
foreground or background groups.Comment: 17 pages, 16 figures, 3 tables, accepted versio
The Yagita invariant of symplectic groups of large rank
Fix a prime , and let be any subring of the complex numbers that is
either integrally closed or contains a primitive th root of 1. For each
we compute the Yagita invariant at the prime for the symplectic
group .Comment: Minor changes compared to first versio
Behavioral activation for smoking cessation and mood management following a cardiac event: results of a pilot randomized controlled trial
Background: Smoking cessation following hospitalization for Acute Coronary Syndrome (ACS) significantly reduces subsequent mortality. Depressed mood is a major barrier to cessation post-ACS. Although existing counseling treatments address smoking and depression independently in ACS patients, no integrated treatment addresses both. We developed an integrated treatment combining gold standard cessation counseling with behavioral activation-based mood management; Behavioral Activation Treatment for Cardiac Smokers (BAT-CS). The purpose of this pilot randomized controlled trial was to test feasibility, acceptability, and preliminary efficacy of BAT-CS vs. Standard of Care (SC).
Methods: Participants were recruited during hospitalization for ACS and were randomly assigned to BAT-CS or SC. The nicotine patch was offered in both conditions. Smoking, mood, and stress outcomes were collected at end-of-treatment and 24-week follow-up.
Results: Fifty-nine participants (28 BAT-CS, 31 SC) were recruited over 42 weeks, and assessment completion was above 80% in both conditions. Treatment acceptability and fidelity were high. At 24 week follow-up adjusted odds ratios favoring BAT-CS were 1.27 (95% CI: 0.41–3.93) for 7-day point prevalence abstinence and 1.27 (95% CI: 0.42–3.82) for continuous abstinence. Time to first smoking lapse was significantly longer in BAT-CS (62.4 vs. 31.8 days, p = 0.03). At 24-weeks, effect sizes for mood and stress outcomes ranged from η2 of.07–.11, with significant between treatment effects for positive affect, negative affect, and stress.
Conclusions: The design of this study proved feasible and acceptable. Results provide preliminary evidence that combining behavioral activation with standard smoking cessation counseling could be efficacious for this high risk population. A larger trial with longer follow-up is warranted.
Trial registration: NCT01964898. First received by clinicaltrials.gov October 15, 2013
Non-disturbing quantum measurements
We consider pairs of quantum observables (POVMs) and analyze the relation
between the notions of non-disturbance, joint measurability and commutativity.
We specify conditions under which these properties coincide or
differ---depending for instance on the interplay between the number of outcomes
and the Hilbert space dimension or on algebraic properties of the effect
operators. We also show that (non-)disturbance is in general not a symmetric
relation and that it can be decided and quantified by means of a semidefinite
program.Comment: Minor corrections in v
Characterization of the Sequential Product on Quantum Effects
We present a characterization of the standard sequential product of quantum
effects. The characterization is in term of algebraic, continuity and duality
conditions that can be physically motivated.Comment: 11 pages. Accepted for publication in the Journal of Mathematical
Physic
The Standard Model of Quantum Measurement Theory: History and Applications
The standard model of the quantum theory of measurement is based on an
interaction Hamiltonian in which the observable-to-be-measured is multiplied
with some observable of a probe system. This simple Ansatz has proved extremely
fruitful in the development of the foundations of quantum mechanics. While the
ensuing type of models has often been argued to be rather artificial, recent
advances in quantum optics have demonstrated their prinicpal and practical
feasibility. A brief historical review of the standard model together with an
outline of its virtues and limitations are presented as an illustration of the
mutual inspiration that has always taken place between foundational and
experimental research in quantum physics.Comment: 22 pages, to appear in Found. Phys. 199
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