1,155 research outputs found
Effective actions on the squashed three-sphere
The effective actions of a scalar and massless spin-half field are determined
as functions of the deformation of a symmetrically squashed three-sphere. The
extreme oblate case is particularly examined as pertinant to a high temperature
statistical mechanical interpretation that may be relevant for the holographic
principle. Interpreting the squashing parameter as a temperature, we find that
the effective `free energies' on the three-sphere are mixtures of thermal
two-sphere scalars and spinors which, in the case of the spinor on the
three-sphere, have the `wrong' thermal periodicities. However the free energies
do have the same leading high temperature forms as the standard free energies
on the two-sphere. The next few terms in the high-temperature expansion are
also explicitly calculated and briefly compared with the Taub-Bolt-AdS bulk
result.Comment: 23 pages, JyTeX. Conclusion slightly amended, one equation and minor
misprints correcte
Quantum effects in a rotating spacetime
The behavior of a arbitrary coupled quantum scalar field is studied in the
background of the G\"odel spacetime. Closed forms are derived for the effective
action and the vacuum expectation value of quadratic field fluctuations by
using -function regularization. Based on these results, we argue that
causality violation presented in this spacetime can not be removed by quantum
effects.Comment: 17 pages, LaTe
The Finiteness Requirement for Six-Dimensional Euclidean Einstein Gravity
The finiteness requirement for Euclidean Einstein gravity is shown to be so
stringent that only the flat metric is allowed. We examine counterterms in 4D
and 6D Ricci-flat manifolds from general invariance arguments.Comment: 15 pages, Introduction is improved, many figures(eps
Finite-Temperature Cosmological Phase Transition in a Rotating Spacetime
We use the -function regularization method to evaluate the finite
temperature 1-loop effective potential for theory in the Godel
spacetime. It is used to study the effects of temperature and curvature
coupling on the cosmological phase transition in the rotational spacetime. From
our results the critical temperature of symmetry restoration, which is a
function of curvature coupling and magnitude of spacetime rotation, can be
determined.Comment: Latex 14 page
Use of evidence to support healthy public policy: a policy effectiveness-feasibility loop
Public policy plays a key role in improving population health and in the control of diseases, including non-communicable diseases.
However, an evidence-based approach to formulating healthy public policy has been difficult to implement, partly on account of barriers
that hinder integrated work between researchers and policy-makers. This paper describes a “policy effectiveness–feasibility loop” (PEFL) that
brings together epidemiological modelling, local situation analysis and option appraisal to foster collaboration between researchers and
policy-makers. Epidemiological modelling explores the determinants of trends in disease and the potential health benefits of modifying
them. Situation analysis investigates the current conceptualization of policy, the level of policy awareness and commitment among key
stakeholders, and what actually happens in practice, thereby helping to identify policy gaps. Option appraisal integrates epidemiological
modelling and situation analysis to investigate the feasibility, costs and likely health benefits of various policy options. The authors illustrate
how PEFL was used in a project to inform public policy for the prevention of cardiovascular diseases and diabetes in four parts of the eastern
Mediterranean. They conclude that PEFL may offer a useful framework for researchers and policy-makers to successfully work together to
generate evidence-based policy, and they encourage further evaluation of this approach
Modulation of emotional appraisal by false physiological feedback during fMRI
BACKGROUND
James and Lange proposed that emotions are the perception of physiological reactions. Two-level theories of emotion extend this model to suggest that cognitive interpretations of physiological changes shape self-reported emotions. Correspondingly false physiological feedback of evoked or tonic bodily responses can alter emotional attributions. Moreover, anxiety states are proposed to arise from detection of mismatch between actual and anticipated states of physiological arousal. However, the neural underpinnings of these phenomena previously have not been examined.
METHODOLOGY/PRINCIPAL FINDINGS
We undertook a functional brain imaging (fMRI) experiment to investigate how both primary and second-order levels of physiological (viscerosensory) representation impact on the processing of external emotional cues. 12 participants were scanned while judging face stimuli during both exercise and non-exercise conditions in the context of true and false auditory feedback of tonic heart rate. We observed that the perceived emotional intensity/salience of neutral faces was enhanced by false feedback of increased heart rate. Regional changes in neural activity corresponding to this behavioural interaction were observed within included right anterior insula, bilateral mid insula, and amygdala. In addition, right anterior insula activity was enhanced during by asynchronous relative to synchronous cardiac feedback even with no change in perceived or actual heart rate suggesting this region serves as a comparator to detect physiological mismatches. Finally, BOLD activity within right anterior insula and amygdala predicted the corresponding changes in perceived intensity ratings at both a group and an individual level.
CONCLUSIONS/SIGNIFICANCE
Our findings identify the neural substrates supporting behavioural effects of false physiological feedback, and highlight mechanisms that underlie subjective anxiety states, including the importance of the right anterior insula in guiding second-order "cognitive" representations of bodily arousal state
Modulation of emotional appraisal by false physiological feedback during fMRI
BACKGROUND
James and Lange proposed that emotions are the perception of physiological reactions. Two-level theories of emotion extend this model to suggest that cognitive interpretations of physiological changes shape self-reported emotions. Correspondingly false physiological feedback of evoked or tonic bodily responses can alter emotional attributions. Moreover, anxiety states are proposed to arise from detection of mismatch between actual and anticipated states of physiological arousal. However, the neural underpinnings of these phenomena previously have not been examined.
METHODOLOGY/PRINCIPAL FINDINGS
We undertook a functional brain imaging (fMRI) experiment to investigate how both primary and second-order levels of physiological (viscerosensory) representation impact on the processing of external emotional cues. 12 participants were scanned while judging face stimuli during both exercise and non-exercise conditions in the context of true and false auditory feedback of tonic heart rate. We observed that the perceived emotional intensity/salience of neutral faces was enhanced by false feedback of increased heart rate. Regional changes in neural activity corresponding to this behavioural interaction were observed within included right anterior insula, bilateral mid insula, and amygdala. In addition, right anterior insula activity was enhanced during by asynchronous relative to synchronous cardiac feedback even with no change in perceived or actual heart rate suggesting this region serves as a comparator to detect physiological mismatches. Finally, BOLD activity within right anterior insula and amygdala predicted the corresponding changes in perceived intensity ratings at both a group and an individual level.
CONCLUSIONS/SIGNIFICANCE
Our findings identify the neural substrates supporting behavioural effects of false physiological feedback, and highlight mechanisms that underlie subjective anxiety states, including the importance of the right anterior insula in guiding second-order "cognitive" representations of bodily arousal state
Free and self-interacting scalar fields in the presence of conical singularities
Free and self-interacting scalar fields in the presence of conical
singularities are analized in some detail. The role of such a kind of
singularities on free and vacuum energy and also on the one-loop effective
action is pointed out using -function regularization and heat-kernel
techniques.Comment: 20 Pages, RevTex, UTF30
Critical Thinking Activities and the Enhancement of Ethical Awareness: An application of a ‘Rhetoric of Disruption’ to the undergraduate general education classroom
This article explores how critical thinking activities and assignments can function to enhance students’ ethical awareness and sense of civic responsibility. Employing Levinas’s Othercentered theory of ethics, Burke’s notion of ‘the paradox of substance’, and Murray’s concept of ‘a rhetoric of disruption’, this article explores the nature of critical thinking activities designed to have students question their (often taken-for-granted) moral assumptions and interrogate their (often unexamined) moral identities. This article argues that such critical thinking activities can trigger a metacognitive destabilization of subjectivity, understood as a dialectical prerequisite (along with exposure to otherness) for increased ethical awareness. This theoretical model is illustrated through a discussion of three sample classroom activities designed to destabilize moral assumptions and identity, thereby clearing the way for a heightened acknowledgment of otherness. In so doing, this article provides an alternative (and dialectically inverted) strategy for addressing one of the central goals of many General Education curricula: the development of ethical awareness and civic responsibility. Rather than introducing students to alternative perspectives and divergent cultures with the expectation that heightened moral awareness will follow, this article suggests classroom activities and course assignments aimed at disrupting moral subjectivity and creating an opening in which otherness can be more fully acknowledged and the diversity of our world more fully appreciated
Finite Temperature Effective Potential for Gauge Models in de Sitter Space
The one-loop effective potential for gauge models in static de Sitter space
at finite temperatures is computed by means of the --function method. We
found a simple relation which links the effective potentials of gauge and
scalar fields at all temperatures.
In the de Sitter invariant and zero-temperature states the potential for the
scalar electrodynamics is explicitly obtained, and its properties in these two
vacua are compared. In this theory the two states are shown to behave similarly
in the regimes of very large and very small radii a of the background space.
For the gauge symmetry broken in the flat limit () there is a
critical value of a for which the symmetry is restored in both quantum states.
Moreover, the phase transitions which occur at large or at small a are of the
first or of the second order, respectively, regardless the vacuum considered.
The analytical and numerical analysis of the critical parameters of the above
theory is performed. We also established a class of models for which the kind
of phase transition occurring depends on the choice of the vacuum.Comment: 23 pages, LaTeX, 5 figure.ep
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