1,546 research outputs found
On Kostant's partial order on hyperbolic elements
We study Kostant's partial order on the elements of a semisimple Lie group in
relations with the finite dimensional representations. In particular, we prove
the converse statement of [3, Theorem 6.1] on hyperbolic elements.Comment: 7 page
Wigner transform and pseudodifferential operators on symmetric spaces of non-compact type
We obtain a general expression for a Wigner transform (Wigner function) on
symmetric spaces of non-compact type and study the Weyl calculus of
pseudodifferential operators on them
Identifying obstacles to participation in a questionnaire survey on widowers' grief
Background: The aim of this study was to determine if Icelandic widowers might foresee obstacles to responding to a
questionnaire on bereavement. Also, we sought to compare the proportion of men reporting obstacles in a telephone
interview to the actual response rate in the questionnaire survey.
Methods: The study was part of a nation-wide survey of widowers who lost their wives in 1999, 2000, and 2001. This
included all widowers born in Iceland 1924-1969 (aged 30-75 years) who were alive, and residing in Iceland at the time
of the study. A telephone poll was conducted prior to sending out a questionnaire to determine if the widowers would
be interested in responding, or if they could see obstacles, which could affect their willingness to respond to a
subsequent questionnaire survey. The telephone poll was repeated five years later with a random sample of the
original study base to determine if views initially expressed towards the questionnaire survey, had changed over time.
Results: Of the 357 eligible widowers, 11 had died prior to the first telephone interview, yielding a study population of
346 widowers. Of those, 296 (86%) were reachable and all of these (100%) were willing to participate in the telephone
survey. Of them, 55% identified obstacles to participation in the questionnaire survey. Men under 60 years were less
likely to identify obstacles. Years from loss (second through fourth years) were not associated with reporting obstacles
to participation. The response rate in the epidemiological questionnaire survey following the telephone interview was
62% (216/346).
Of those who did identify obstacles 23%, did not did not identify any particular obstacle, but 33% stated that "they
felt bad" or that it would be "a painful experience" or that they felt "uncomfortable" talking about their grief. About
18% stated their grief was "a private matter"; 6% stated that they did not want to be "stuck with their grief"; 9% said
that it was "too late" to talk about their grief or that they "wanted to look towards their future". Additionally, 11%
stated "other reasons", including responses like: "it's too early to talk about it", and "I have started another relationship
- don't want complications."
Conclusions: The willingness to participate in the telephone interview was high and indicates a strong interest in the
subject. Also, exposure to the study appeared to increase willingness to participate, since many men who initially could
see obstacles to participation, actually participated in the epidemiological questionnaire survey. However,
approximately one third of the men who initially identified obstacles to participation remained negative toward
participation throughout the study period.NonePublishe
Social correlates of cigarette smoking among Icelandic adolescents: A population-based cross-sectional study
BACKGROUND: Previous research has shown that between 80 and 90 percent of adult
smokers report having started smoking before 18 years of age. Several studies
have revealed that multiple social factors influence the likelihood of smoking
during adolescence, the period during which the onset of smoking usually occurs.
To better understand the social mechanisms that influence adolescent smoking, we
analyzed the relationship and relative importance of a broad spectrum of social
variables in adolescent smoking in Iceland, a Nordic country with high per-capita
income.
METHODS: We used cross-sectional data from 7,430 14- to 16 year-old
students (approximately 81% of all Icelanders in these age cohorts) in the 2006
Youth in Iceland study. The Youth in Iceland studies are designed to investigate
the role of several cognitive, behavioral, and social factors in the lives of
adolescents, and the data collected are used to inform the design,
implementation, and evaluation of substance use prevention programs that are
being developed by Icelandic social scientists, policy makers, and practitioners.
RESULTS: Our analysis revealed that friends' smoking behavior and attitude toward
smoking were strongly associated with adolescent smoking and other tobacco use,
as well as alcohol consumption during the previous 30 days. Main protective
factors were parent's perceived attitude toward smoking, the quantity of time
spent with parents, absence of serious verbal conflict between parents and
adolescents, and participation in physical activity. Family structure was related
to adolescent smoking to a small extent, but other background factors were not.
CONCLUSION: We conclude that multiple social factors are related to adolescent
smoking. Parents and other primary preventive agents need to be informed about
the complicated nature of the adolescent social world in order to maximize their
impact.Icelandic Alcohol and Drug Prevention CommitteeIcelandic Red CrossCity of ReykjavikSports and Recreational Committee of Reykjavik to the Icelandic Centre for Social Research and AnalysisIcelandic Centre for Research (RANNÍS)Publishe
On the solution of the initial value constraints for general relativity coupled to matter in terms of Ashtekar's variables
The method of solution of the initial value constraints for pure canonical
gravity in terms of Ashtekar's new canonical variables due to CDJ is further
developed in the present paper. There are 2 new main results : 1) We extend the
method of CDJ to arbitrary matter-coupling again for non-degenerate metrics :
the new feature is that the 'CDJ-matrix' adopts a nontrivial antisymmetric part
when solving the vector constraint and that the Klein-Gordon-field is used,
instead of the symmetric part of the CDJ-matrix, in order to satisfy the scalar
constraint. 2) The 2nd result is that one can solve the general initial value
constraints for arbitrary matter coupling by a method which is completely
independent of that of CDJ. It is shown how the Yang-Mills and gravitational
Gauss constraints can be solved explicitely for the corresponding electric
fields. The rest of the constraints can then be satisfied by using either
scalar or spinor field momenta. This new trick might be of interest also for
Yang-Mills theories on curved backgrounds.Comment: Latex, 15 pages, PITHA93-1, January 9
Operator Product on Locally Symmetric Spaces of Rank One and the Multiplicative Anomaly
The global multiplicative properties of Laplace type operators acting on
irreducible rank one symmetric spaces are considered. The explicit form of the
multiplicative anomaly is derived and its corresponding value is calculated
exactly, for important classes of locally symmetric spaces and different
dimensions.Comment: Int. Journal of Modern Physics A, vol. 18 (2003), 2179-218
Space-time symplectic extension
It is conjectured that in the origin of space-time there lies a symplectic
rather than metric structure. The complex symplectic symmetry Sp(2l,C), l\ge1
instead of the pseudo-orthogonal one SO(1,d-1), d\ge4 is proposed as the
space-time local structure group. A discrete sequence of the metric space-times
of the fixed dimensionalities d=(2l)^2 and signatures, with l(2l-1) time-like
and l(2l+1) space-like directions, defined over the set of the Hermitian
second-rank spin-tensors is considered as an alternative to the
pseudo-Euclidean extra dimensional space-times. The basic concepts of the
symplectic framework are developed in general, and the ordinary and
next-to-ordinary space-time cases with l=1,2, respectively, are elaborated in
more detail. In particular, the scheme provides the rationale for the
four-dimensionality and 1+3 signature of the ordinary space-time.Comment: 15 pp, LaTe
- …