21,917 research outputs found
Correlated Equilibria of Classical Strategic Games with Quantum Signals
Correlated equilibria are sometimes more efficient than the Nash equilibria
of a game without signals. We investigate whether the availability of quantum
signals in the context of a classical strategic game may allow the players to
achieve even better efficiency than in any correlated equilibrium with
classical signals, and find the answer to be positive.Comment: 8 pages, LaTe
The effects of first generation status upon the first year college success patterns of students attending an urban multi-campus community college
Community colleges have a special interest in identifying factors associated with retention and graduation. Additionally, community college administrators are interested in the identification of retention factors and how to structure administrative policy and procedure that address college success patterns of all students. The first generation student is of particular concern. The first step in developing student-centered policies and practices is to gain a clear understanding of demographic characteristics and first year academic behavior of the enrolled student. For an urban community college in southeastern Michigan this means learning more about first-generation students, who make up a significant portion of the student body. The problem investigated in this study was to determine if there were differences in first-year college success patterns (retention) between first-generation students and non first-generation students attending a multi-campus community college. The purpose of the study was to determine the effects of remediation, family income, and the influence of a parent\u27s highest level of education upon college success patterns (retention) of first-generation students. Information from 713 student cases was taken from the cohort of all students who enrolled and applied for financial aid during the fall 1994 semester. Approximately 80% of the student population applies for financial aid. The results of data analyses showed significant differences between first-generation and non first-generation community college students relative to the number of semesters attended and cumulative grade point average. A stepwise multiple regression analysis resulted in cumulative grade point average, financial aid recipient, enrolled in a transfer/traditional program, enrolled in courses classified as below college level (remediation), and attending campuses other than Eastern and Downtown as significant predictors of college success. These variables combined explained 23% of the variance within first year college success of students attending a multi-campus community college. No significant differences were found between the two groups related to college success relative to the number of credit hours completed, number of courses classified as below college level (remediation), the highest level of education completed by father, highest level of education completed by mother, family income, types of high school attended, age, gender, and ethnicity
Slow dynamics in a turbulent von K\'arm\'an swirling flow
We present an experimental study of a turbulent von K\'arm\'an flow produced
in a cylindrical container using two propellers. The mean flow is stationary up
to , where a bifurcation takes place. The new regime breaks some
symmetries of the problem, and is time-dependent. The axisymmetry is broken by
the presence of equatorial vortices with a precession movement, being the
velocity of the vortices proportional to the Reynolds number. The reflection
symmetry through the equatorial plane is broken, and the shear layer of the
mean flow appears displaced from the equator. These two facts appear
simultaneously. In the exact counterrotating case, a bistable regime appears
between both mirrored solutions and spontaneous reversals of the azimuthal
velocity are registered. This evolution can be explained using a three-well
potential model with additive noise. A regime of forced periodic response is
observed when a very weak input signal is applied.Comment: Improved model, additional results and figures, accepted in PR
Optical von Neumann measurement
We present an optical scheme that realizes the standard von Neumann
measurement model, providing an indirect measurement of a quadrature of the
field with controllable Gaussian state-reduction. The scheme is made of simple
optical elements, as laser sources, beam splitters, and phase sensitive
amplifiers, along with a feedback mechanism that uses a Pockels cell. We show
that the von Neumann measurement is achieved without the need of working in a
ultra-short pulsed regime.Comment: One latex figure. Accepted on Phys. Lett.
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Level of evidence used in recommendations by the National Comprehensive Cancer Network (NCCN) guidelines beyond Food and Drug Administration approvals.
BackgroundA previous analysis of 113 National Comprehensive Cancer Network® (NCCN®) recommendations reported that NCCN frequently recommends beyond Food and Drug Administration (FDA)-approved indications (44 off-label recommendations) and claimed that the evidence for these recommendations was weak.MethodsIn order to determine the strength of the evidence, we carried out an in-depth re-analysis of the 44 off-label recommendations listed in the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®).ResultsOf the 44 off-label recommendations, 14 were later approved by the FDA and/or are supported by randomized controlled trial (RCT) data. In addition, 13 recommendations were either very minor extrapolations from the FDA label (n = 8) or were actually on-label (n = 5). Of the 17 remaining extrapolations, 8 were for mechanism-based agents applied in rare cancers or subsets with few available treatment options (median response rate = 43%), 7 were based on non-RCT data showing significant efficacy (>50% response rates), and 2 were later removed from the NCCN Guidelines because newer therapies with better activity and/or safety became available.ConclusionOff-label drug use is a frequent component of care for patients with cancer in the United States. Our findings indicate that when the NCCN recommends beyond the FDA-approved indications, the strength of the evidence supporting such recommendations is robust, with a significant subset of these drugs later becoming FDA approved or supported by RCT. Recommendations without RCT data are often for mechanism-based drugs with high response rates in rare cancers or subsets without effective therapies
Not an open cluster after all: the NGC 6863 asterism in Aquila
Shortly after birth, open clusters start dissolving; gradually losing stars
into the surrounding star field. The time scale for complete disintegration
depends both on their initial membership and location within the Galaxy. Open
clusters undergoing the terminal phase of cluster disruption or open cluster
remnants (OCRs) are notoriously difficult to identify. From an observational
point, a combination of low number statistics and minimal contrast against the
general stellar field conspire to turn them into very challenging objects. To
make the situation even worst, random samples of field stars often display
features that may induce to classify them erroneously as extremely evolved open
clusters. In this paper, we provide a detailed study of the stellar content and
kinematics of NGC 6863, a compact group of a few stars located in Aquila and
described by the POSS as a non existent cluster. Nonetheless, this object has
been recently classified as OCR. The aim of the present work is to either
confirm or disprove its OCR status by a detailed star-by-star analysis. The
analysis is performed using wide-field photometry in the UBVI pass-band, proper
motions from the UCAC3 catalogue, and high resolution spectroscopy as well as
results from extensive -body calculations. Our results show that the four
brightest stars commonly associated to NGC 6863 form an asterism, a group of
non-physically associated stars projected together, leading to the conclusion
that NGC 6863 is not a real open cluster.Comment: 10 pages, 8 eps figure, in press in Astronomy and Astrophysis.
Abstract shortened to fit i
Earthquake Mitigation by Blast Densification
This paper presents a case study of blast densification of a site underlain by a loose, saturated, natural sand deposit. Densification was performed to mitigate the risk of liquefaction from earthquake-induced ground vibrations. The work was implemented as part of the design-build construction of the Marine Corps Reserve Training Center at the Westover Air Reserve Base in Chicopee, Massachusetts. Following review of preliminary subsurface data at the site, the contractor retained a team to design and implement ground improvement by blast densification. The team, led by a geotechnical engineering firm, included a blaster, a driller, and a cone penetrometer testing firm. The team performed the analyses, design, implementation and post-densification testing to carry out and document the effectiveness of the blast densification. The paper presents the densification program and comparison of the pre- and post blasting data including settlement results. The project duration including pre-blasting evaluation, design, implementation, and post-blasting evaluation was less than two months. This demonstrates that deep blasting can be successfully implemented as part of fast-track, design-build procurement to execute a complex ground improvement program. It also demonstrates that while the technique is not commonly used, it is sufficiently well understood to provide a flexible and cost effective alternative to the more commonly used ground improvement methods under the right conditions
On Randomness in Quantum Mechanics
The quantum mechanical probability densities are compared with the
probability densities treated by the theory of random variables. The relevance
of their difference for the interpretation of quantum mechanics is commented
Poisson-Lie T-Duality: the Path-Integral Derivation
We formulate Poisson-Lie T-duality in a path-integral manner that allows us
to analyze the quantum corrections. Using the path-integral, we rederive the
most general form of a Poisson-Lie dualizeable background and the generalized
Buscher transformation rules it has to satisfy.Comment: 16 pages, plain LaTeX 2e, one paragraph added to the conclusions;
this is the final version accepted by Physics Letters
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