13,333 research outputs found
An attentional control task reduces intrusive thoughts about smoking.
INTRODUCTION: Attentional control tasks such as body scanning and following isometric exercise instructions have been shown to reduce smoking cravings, apparently by reducing stress (Ussher, M., Cropley, M., Playle, S., Mohidin, R., & West, R. [2009]. Effect of isometric exercise and body scanning on cigarette cravings and withdrawal symptoms. Addiction, 104, 1251-1257. doi:10.1111/j.1360-0443.2009.02605.x). Related work based upon elaborated intrusion theory (Kavanagh, D. J., Andrade, J., & May, J. [2005]. Imaginary relish and exquisite torture: The elaborated intrusion theory of desire. Psychological Review, 112, 446-467. doi:10.1037/0033-295X.112.2.446) has shown that similar tasks can reduce hungry participants' involuntary food-related thoughts (May, J., Andrade, J., Batey, H., Berry, L.-M., & Kavanagh, D. [2010]. Less food for thought: Impact of attentional instructions on intrusive thoughts about snack foods. Appetite, 55, 279-287. doi:10.1016/j.appet.2010.06.014). This study tests the effect of body scanning instructions upon smoking-related thoughts as well as craving. METHODS: Twenty-seven smokers took part in 2 counterbalanced sessions, on different days, having been asked to abstain from smoking for 2 hr. In each session, they followed audio instructions for three 10-min blocks during which their thoughts were probed 10 times. In the first and third blocks, they were instructed to let their mind wander; during the second block of the control session, they also let their mind wander, but in the experimental session, they followed body scanning instructions. "Smoking thought frequency" was assessed using thought probes; "Craving" was measured using Factor 1 of the Questionnaire on Smoking Urges (Tiffany, S. T., & Drobes, D. J. [1991]. The development and initial validation of a questionnaire on smoking urges. British Journal of Addiction, 86, 1467-1476. doi:10.1111/j.1360-0443.1991.tb01732.x). RESULTS: Participants reported fewer smoking-related thoughts and lower smoking cravings in the body scanning block of the experimental session, whereas they rose in the comparable mind-wandering block of the control session. The reduction in thoughts during the body scanning correlated with the corresponding reduction in craving. CONCLUSIONS: Body scanning reduces cravings and reduces the frequency or shortens the duration of smoking thoughts. Attentional control strategies may form a useful part of smoking cessation practices
Teleparallel Spin Connection
A new expression for the spin connection of teleparallel gravity is proposed,
given by minus the contorsion tensor plus a zero connection. The corresponding
minimal coupling is covariant under local Lorentz transformation, and
equivalent to the minimal coupling prescription of general relativity. With
this coupling prescription, therefore, teleparallel gravity turns out to be
fully equivalent to general relativity, even in the presence of spinor fields.Comment: 2 pages, RevTeX, to appear in Phys. Rev D (Brief Report
Defect-induced spin-glass magnetism in incommensurate spin-gap magnets
We study magnetic order induced by non-magnetic impurities in quantum
paramagnets with incommensurate host spin correlations. In contrast to the
well-studied commensurate case where the defect-induced magnetism is spatially
disordered but non-frustrated, the present problem combines strong disorder
with frustration and, consequently, leads to spin-glass order. We discuss the
crossover from strong randomness in the dilute limit to more conventional glass
behavior at larger doping, and numerically characterize the robust short-range
order inherent to the spin-glass phase. We relate our findings to magnetic
order in both BiCu2PO6 and YBa2Cu3O6.6 induced by Zn substitution.Comment: 6 pages, 5 figs, (v2) real-space RG results added; discussion
extended, (v3) final version as publishe
Gravitation and Duality Symmetry
By generalizing the Hodge dual operator to the case of soldered bundles, and
working in the context of the teleparallel equivalent of general relativity, an
analysis of the duality symmetry in gravitation is performed. Although the
basic conclusion is that, at least in the general case, gravitation is not dual
symmetric, there is a particular theory in which this symmetry shows up. It is
a self dual (or anti-self dual) teleparallel gravity in which, due to the fact
that it does not contribute to the interaction of fermions with gravitation,
the purely tensor part of torsion is assumed to vanish. The ensuing fermionic
gravitational interaction is found to be chiral. Since duality is intimately
related to renormalizability, this theory may eventually be more amenable to
renormalization than teleparallel gravity or general relativity.Comment: 7 pages, no figures. Version 2: minor presentation changes,
references added. Accepted for publication in Int. J. Mod. Phys.
Rotation intrinsic spin coupling--the parallelism description
For the Dirac particle in the rotational system, the rotation induced inertia
effect is analogously treated as the modification of the "spin connection" on
the Dirac equation in the flat spacetime, which is determined by the equivalent
tetrad. From the point of view of parallelism description of spacetime, the
obtained torsion axial-vector is just the rotational angular velocity, which is
included in the "spin connection". Furthermore the axial-vector spin coupling
induced spin precession is just the rotation-spin(1/2) interaction predicted by
Mashhoon. Our derivation treatment is straightforward and simplified in the
geometrical meaning and physical conception, however the obtained conclusions
are consistent with that of the other previous work.Comment: 10 pages, no figur
Dirac spinor fields in the teleparallel gravity: comment on "Metric-affine approach to teleparallel gravity"
We show that the coupling of a Dirac spinor field with the gravitational
field in the teleparallel equivalent of general relativity is consistent. For
an arbitrary SO(3,1) connection there are two possibilities for the coupling of
the spinor field with the gravitational field. The problems of consistency
raised by Y. N. Obukhov and J. G. Pereira in the paper {\it Metric-affine
approach to teleparallel gravity} [gr-qc/0212080] take place only in the
framework of one particular coupling. By adopting an alternative coupling the
consistency problem disappears.Comment: 8 pages, Latex file, no figures, to appear in the Phys. Rev. D as a
Commen
Improving Dental Experiences by Using Virtual Reality Distraction: A Simulation Study
Dental anxiety creates significant problems for both patients and the dental profession. Some distraction interventions are already used by healthcare professionals to help patients cope with unpleasant procedures. The present study is novel because it a) builds on evidence that natural scenery is beneficial for patients, and b) uses a Virtual Reality (VR) representation of nature to distract participants. Extending previous work that has investigated pain and anxiety during treatment, c) we also consider the longer term effects in terms of more positive memories of the treatment, building on a cognitive theory of memory (Elaborated Intrusions). Participants (n = 69) took part in a simulated dental experience and were randomly assigned to one of three VR conditions (active vs. passive vs. control). In addition, participants were distinguished into high and low dentally anxious according to a median split resulting in a 362 between-subjects design. VR distraction in a simulated dental context affected memories a week later. The VR distraction had effects not only on concurrent experiences, such as perceived control, but longitudinally upon the vividness of memories after the dental experience had ended. Participants with higher dental anxiety (for whom the dental procedures were presumably more aversive) showed a greater reduction in memory vividness than lower dental-anxiety participants. This study thus suggests that VR distractions can be considered as a relevant intervention for cycles of care in which people’s previous experiences affect their behaviour for future events
Energy-momentum and angular momentum densities in gauge theories of gravity
In the \bar{\mbox{\rm Poincar\'{e}}} gauge theory of gravity, which has
been formulated on the basis of a principal fiber bundle over the space-time
manifold having the covering group of the proper orthochronous Poincar\'{e}
group as the structure group, we examine the tensorial properties of the
dynamical energy-momentum density and the ` `
spin" angular momentum density of the
gravitational field. They are both space-time vector densities, and transform
as tensors under {\em global} - transformations. Under {\em local}
internal translation, is invariant, while
transforms inhomogeneously. The dynamical
energy-momentum density and the ` ` spin"
angular momentum density of the matter field
are also examined, and they are known to be space-time vector densities and to
obey tensorial transformation rules under internal \bar{\mbox{\rm
Poincar\'{e}}} gauge transformations. The corresponding discussions in
extended new general relativity which is obtained as a teleparallel limit of
\bar{\mbox{\rm Poincar\'{e}}} gauge theory are also given, and
energy-momentum and ` ` spin" angular momentum densities are known to be well
behaved. Namely, they are all space-time vector densities, etc. In both
theories, integrations of these densities on a space-like surface give the
total energy-momentum and {\em total} (={\em spin}+{\em orbital}) angular
momentum for asymptotically flat space-time. The tensorial properties of
canonical energy-momentum and ` ` extended orbital angular momentum" densities
are also examined.Comment: 18 page
Gravitational Energy-Momentum Density in Teleparallel Gravity
In the context of a gauge theory for the translation group, a conserved
energy-momentum gauge current for the gravitational field is obtained. It is a
true spacetime and gauge tensor, and transforms covariantly under global
Lorentz transformations. By rewriting the gauge gravitational field equation in
a purely spacetime form, it becomes the teleparallel equivalent of Einstein's
equation, and the gauge current reduces to the M{\o}ller's canonical
energy-momentum density of the gravitational field.Comment: RevTeX, 4 pages, no figures, to appear in Phys. Rev. Let
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