34,003 research outputs found
A generalized structure of Bell inequalities for bipartite arbitrary dimensional systems
We propose a generalized structure of Bell inequalities for arbitrary
d-dimensional bipartite systems, which includes the existing two types of Bell
inequalities introduced by Collins-Gisin-Linden-Massar-Popescu [Phys. Rev.
Lett. 88, 040404 (2002)] and Son-Lee-Kim [Phys. Rev. Lett. 96, 060406 (2006)].
We analyze Bell inequalities in terms of correlation functions and joint
probabilities, and show that the coefficients of correlation functions and
those of joint probabilities are in Fourier transform relations. We finally
show that the coefficients in the generalized structure determine the
characteristics of quantum violation and tightness.Comment: 6 pages, 1 figur
Neutrino oscillations and Big Bang Nucleosynthesis
We outline how relic neutrino asymmetries may be generated in the early
universe via active-sterile neutrino oscillations. We discuss possible
consequences for big bang nucleosynthesis, within the context of a particular
4-neutrino model.Comment: 6 pages. Talk given at NuFACT'01 workshop, Tsukuba, Japan (May 2001
Microcanonical solution of lattice models with long range interactions
We present a general method to obtain the microcanonical solution of lattice
models with long range interactions. As an example, we apply it to the long
range Ising chain, focusing on the role of boundary conditions.Comment: 6 pages, proceedings of the NEXT 2001 conferenc
Faithful test of non-local realism with entangled coherent states
We investigate the violation of Leggett's inequality for non-local realism
using entangled coherent states and various types of local measurements. We
prove mathematically the relation between the violation of the
Clauser-Horne-Shimony-Holt form of Bell's inequality and Leggett's one when
tested by the same resources. For Leggett inequalities, we generalize the
non-local realistic bound to systems in Hilbert spaces larger than
bidimensional ones and introduce an optimization technique that allows to
achieve larger degrees of violation by adjusting the local measurement
settings. Our work describes the steps that should be performed to produce a
self-consistent generalization of Leggett's original arguments to
continuous-variable states.Comment: 8 pages, 6 figures, to be published in Phys. Rev.
Synchronisation and MSW sharpening of neutrinos propagating in a flavour blind medium
We consider neutrino oscillations in a medium in which scattering processes
are blind to the neutrino flavour. We present an analytical derivation of the
synchronised behaviour obtained in the limit where the average scattering rate
is much larger than the oscillation frequency. We also examine MSW transitions
in these circumstances, and show that a sharpening of the transition can
result.Comment: 8 pages, 3 figures, accepted for publication in Phys. Lett.
Testing quantum nonlocality by generalized quasiprobability functions
We derive a Bell inequality based on a generalized quasiprobability function
which is parameterized by one non-positive real value. Two types of known Bell
inequalities formulated in terms of the Wigner and Q functions are included as
limiting cases. We investigate violations of our Bell inequalities for single
photon entangled states and two-mode squeezed vacuum states when varying the
detector efficiency. We show that the Bell inequality for the Q function allows
the lowest detection efficiency for violations of local realism.Comment: 6 pages, 3 figure
Seasonal Time Series and Autocorrelation Function Estimation
Time series are demeaned when sample autocorrelation functions are computed. By the same logic it would seem appealing to remove seasonal means from seasonal time series before computing sample autocorrelation functions. Yet, standard practice is only to remove the overall mean and ignore the possibility of seasonal mean shifts in the data. Whether or not time series are seasonally demeaned has very important consequences on the asymptotic behavior of autocorrelation functions (henceforth ACF). Hasza (1980) and Bierens (1993) studied the asymptotic properties of the sample ACF of non-seasonal integrated processes and showed how they depend on the demeaning of the data. In this paper we study the large sample behavior of the ACF when the data generating processes are seasonal with or without seasonal unit roots. The effect on the asymptotic distribution of seasonal mean shifts and their removal is investigated and the practical consequences of these theoretical developments are also discussed. We also examine the small sample behavior of ACF estimates through Monte Carlo simulations.
Lorsqu'on calcule une fonction d'autocorrélation, il est normal d'enlever d'une série la moyenne non conditionnelle. Cette pratique s'applique également dans le cas des séries saisonnières. Pourtant, il serait plus logique d'utiliser des moyennes saisonnières. Hasza (1980) et Bierens (1993) ont étudié l'effet de la moyenne sur l'estimation d'une fonction d'autocorrélation pour un processus avec racine unitaire. Nous examinons le cas de processus avec racines unitaires saisonnières. Nos résultats théoriques de distribution asymptotique, de même que nos simulations de petits échantillons, démontrent l'importance d'enlever les moyennes saisonnières quand on veut identifier proprement les processus saisonniers.Deterministic/stochastic seasonality, model identification, seasonal unit roots, autocorrelation, Saisonalité stochastique et déterministe, identification de modèles, racines unitaires saisonnières,
Addressing Traumatic Stress in the Acute Traumatically Injured Patient
Psychological injuries after an acute traumatic event are commonly overlooked. Currently within United States, there is no consistently utilized screening process that addresses traumatic stress within the acute trauma population. Roy\u27s Adaptation Model guided this project, focusing on the idea that bedside nurses are at the frontline of providing early identification through nursing assessment. The purpose of this pilot study was to evaluate whether the implementation of the Primary Care-Posttraumatic Stress Disorder (PC-PTSD) screening tool by bedside nurses would result in identifying more patients at risk for traumatic stress after an acute trauma as compared with the use of no screening method. This descriptive survey study took place over a 6-week period at a Midwest Level 1 trauma hospital. The results revealed that the tool did not increase the number of health psychology consults when compared with the same 6-week period a year prior when no tool was used. Nonetheless, use of the PC-PTSD tool did trigger 28% of the patients to receive a health psychology consult. Forty-five percent of patients who received a health psychology consult were recommended outpatient therapy. Utilization of this tool by bedside nurses did not adversely increase a number of inappropriate health psychology consults. These results agree with the literature and further suggest that there are a clinically significant number of acute trauma patients who are at risk for traumatic stress. With this screening tool, nurses accurately assessed patients and connected them with timely psychological treatment
Evaluating social skills in long term cochlear implant recipients
A longitudinal study observing cochlear implant recipients\u27 social skills using ratings from their parents and the students themselves over time. The study looked at how adolescents using cochlear implants rate their own social skills compared to an age matched normative group of hearing students, and compared these ratings with social skills ratings obtained from their parents. The study also compared social ratings in adolescence to previous ratings of the same children obtained in elementary school
A Survey of String Programs in the Texas Public Schools
Orchestras suffered considerably during and immediately after the second World War. The rise of military bands and school bands overshadowed the efforts in developing a well-rounded music curriculum of instrumental music in the public school. However, the trend is now reversed. As a shortage of string players for the symphony orchestras become apparent, a move was initiated to provide training in the public schools for students who wished to play string instruments. With the rise of more American composers, conductors, and symphony players, interest increased in string programs and they began to grow.
The purpose of the survey was to present information as to the organization, administration, and maintenance of Texas string programs. The research methods used were (1) study of recent books and periodicals relating to the subject; (2) review of materials used for string instruction; and (3) a questionnaire which was mailed to one hundred string teachers and orchestra directors in the thirty-eight Texas school districts which had established . string programs. Fifty-five of the questionnaires were received from twenty-three of the thirty-eight school districts surveyed. Of the questionnaires received, fifty were completed while five were not completed for various reasons.
The organization and administration of string programs in Texas were found to vary between school districts; however, certain similarities were also revealed. The similarities are as follows:
1. The majority of communities had at least one large senior high school with an enrollment of one thousand and fifty or more.
2. The majority of communities had a population of one hundred thousand or more.
3. The majority of the communities had a college or university which influenced the cultural attitude.
4 . String specialists were employed by the majority of school districts .
5. The majority of string specialists taught on both elementary and secondary levels.
6. The majority of teachers used students for demonstration of instruments when recruiting beginning students.
7. The majority of secondary classes met daily and most secondary teachers held rehearsals outside of school time in addition to the regular class period.
8. The majority of teachers teaching in the elementary schools offered beginning string instruction to fifth or sixth grades.
The materials and equipment used were most often supplied by the school . Elementary schools did not supply beginning books in the majority of schools. The method book most used was the String Builder by Samuel Applebaum. It was revealed that the larger instruments were furnished by most of the schools surveyed, with smaller instruments being furnished by the students.
The responding teachers varied in their opinion of the role of the string program in the school. The majority indicated that the purpose of a string program was enjoyment and enrichment
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