49 research outputs found
On the existence of topological hairy black holes in SU(N) EYM theory with a negative cosmological constant
We investigate the existence of black hole solutions of four dimensional su(N) EYM theory with a negative cosmological constant. Our analysis differs from previous works in that we generalise the field equations to certain non-spherically symmetric spacetimes. We prove the existence of non-trivial solutions for any integer N, with N−1 gauge degrees of freedom. Specifically, we prove two results: existence of solutions for fixed values of the initial parameters and as |Λ|→∞, and existence of solutions for any Λ<0 in some neighbourhood of existing trivial solutions. In both cases we can prove the existence of `nodeless' solutions, i.e. such that all gauge field functions have no zeroes; this fact is of interest as we anticipate that some of them may be stable
Hawking emission from quantum gravity black holes
We address the issue of modelling quantum gravity effects in the evaporation
of higher dimensional black holes in order to go beyond the usual
semi-classical approximation. After reviewing the existing six families of
quantum gravity corrected black hole geometries, we focus our work on
non-commutative geometry inspired black holes, which encode model independent
characteristics, are unaffected by the quantum back reaction and have an
analytical form compact enough for numerical simulations. We consider the
higher dimensional, spherically symmetric case and we proceed with a complete
analysis of the brane/bulk emission for scalar fields. The key feature which
makes the evaporation of non-commutative black holes so peculiar is the
possibility of having a maximum temperature. Contrary to what happens with
classical Schwarzschild black holes, the emission is dominated by low frequency
field modes on the brane. This is a distinctive and potentially testable
signature which might disclose further features about the nature of quantum
gravity.Comment: 36 pages, 18 figures, v2: updated reference list, minor corrections,
version matching that published on JHE
Dissociable effects of monoamine reuptake inhibitors on distinct forms of impulsive behavior in rats
Clinical and Organizational Factors Related to the Reduction of Mechanical Restraint Application in an Acute Ward: An 8-Year Retrospective Analysis
Background:
The purpose of this study was to describe the frequency of mechanical restraint use in an acute psychiatric ward and to analyze which variables may have significantly influenced the use of this procedure. Methods: This retrospective study was conducted in the Servizio Psichiatrico di Diagnosi e Cura (SPDC) of Modena Centro. The following variables of our sample, represented by all restrained patients admitted from 1-1-2005 to 31-12-2012, were analyzed: age, gender, nationality, psychiatric diagnoses, organic comorbidity, state and duration of admission, motivation and duration of restraints, nursing shift and hospitalization day of restraint, number of patients admitted at the time of restraint and institutional changes during the observation period. The above variables were statistically compared with those of all other non-restrained patients admitted to our ward in the same period. Results: Mechanical restraints were primarily used as a safety procedure to manage aggressive behavior of male patients, during the first days of hospitalization and night shifts. Neurocognitive disorders, organic comorbidity, compulsory state and long duration of admission were statistically significantly related to the increase of restraint use (p<.001, multivariate logistic regression). Institutional changes, especially more restricted guidelines concerning restraint application, were statistically significantly related to restraint use reduction (p<.001, chi2 test, multivariate logistic regression). Conclusion: The data obtained highlight that mechanical restraint use was influenced not only by clinical factors, but mainly by staff and policy factors, which have permitted a gradual but significant reduction in the use of this procedure through a multidimensional approach
Understanding within-session loss-chasing: an experimental investigation of the impact of stake size on cognitive control
Loss-chasing is a central feature of problematic gambling, yet it remains a
poorly conceived and understood concept. Loss-chasing is believed to stem from an ero-
sion of cognitive control when gambling. The opportunity to gamble at significantly dis-
parate stake sizes on a gambling activity is considered to be a risk factor for loss-chasing.
This study investigated the impact of gambling at disparate stake sizes on executive
processes integral to maintaining cognitive control when gambling, namely response
inhibition and reflection impulsivity. Frequent adult non-problem gamblers (n = 32)
participated in a repeated measures experiment; and gambled at three disparate stake sizes
(£20, £2 and no stake per bet) on a simulated gambling task. Participants’ response
inhibition performance and reflection impulsivity levels after gambling at various stake
sizes were compared via a go/no-go task and information sampling task, respectively.
Quality of decision-making i.e. the evaluation of available information to make probability
judgements was impaired after gambling at higher stakes in comparison to lower stakes,
indicating an increase in reflection impulsivity. No effect on response inhibition was
observed. Although exploratory, this suggests that the opportunity for participants to
substantially increase stake size on a gambling activity may be a risk factor for impaired
cognitive performance when gambling, and perhaps create vulnerability for within-session
loss-chasing in some players.
Keywords Problem gambling -
Cognitive control -
Loss-chasing -
Response inhibition -
Reflection impulsivit
Modification of Esthetics Using a Combined Orthodontic and a Prosthodontic Approach: A Case Report
A patient sometimes requires a multidisciplinary approach to correct the esthetics and to improve the occlusion. This case report describes the management of an adult female patient with a convex profile, proclined upper and lower anterior teeth, missing upper left lateral incisor and peg shaped upper right lateral incisor tooth through orthodontic and prosthodontic treatment