Quantum corrections to dynamical holographic thermalization: entanglement entropy and other non-local observables

We investigate the thermalization time scale in the planar limit of the SU(N) N=4 SYM plasma at strong yet finite 't Hooft coupling by considering its supergravity dual description, including the full O(alpha'^3) type IIB string theory corrections. We also discuss on the effects of the leading non-planar corrections. We use extended geometric probes in the bulk which are dual to different non-local observables in the N=4 SYM theory. This is carried out within the framework of dynamical holographic thermalization.Comment: 19 pages, 4 figures. V2: References added, 1 figure added, 1 figure corrected, enlarged discussions about extended probes, typos corrected. Published versio

Dynamics of holographic thermalization

Dynamical evolution of thin shells composed by different kinds of degrees of freedom collapsing within asymptotically AdS spaces is explored with the aim of investigating models of holographic thermalization of strongly coupled systems. From the quantum field theory point of view this corresponds to considering different thermal quenches. We carry out a general study of the thermalization time scale using different parameters and space-time dimensions, by calculating renormalized space-like geodesic lengths and rectangular minimal area surfaces as extended probes of thermalization, which are dual to two-point functions and rectangular Wilson loops. Different kinds of degrees of freedom in the shell are described by their corresponding equations of state. We consider a scalar field, as well as relativistic matter, a pressureless massive fluid and conformal matter, which can be compared with the collapse of an AdS-Vaidya thin shell. Remarkably, for conformal matter, the thermalization time scale becomes much larger than the others. Furthermore, in each case we also investigate models where the cosmological constants of the inner and outer regions separated by the shell are different. We found that in this case only a scalar field shell collapses, and that the thermalization time scale is also much larger than the AdS-Vaidya case.Comment: 25 pages, 4 figures. V2: published versio

Clinical and financial consequences of setting up an asthma clinic at St. Luke’s Hospital

The effects of setting up an asthma clinic were assessed in an audit study. A comparison was made between the quality and quantity of medication used by patients before and after attending the asthma clinic. The number and severity of exacerbations during a six month period before and a six month period after attending were also assessed. The cost of treatment before and after was also calculated. In 14% of patients, occupational factors, drugs or underlying lung disease were significant contributors to asthma. The number of acute episodes of severe asthma were reduced from 98 to 47, with hospital admissions falling from 26 to 1. Pulmonary function (%FEV1) improved in the group as a whole with the number of patients having their best FEV above 80% improving from 44 to 71. In spite of the expense of high cost drugs and the running costs of the clinic there were substantial savings largely from the reduced number of hospital admissions. The calculated annual cost fell from Lm 22,769 to Lm 10,654.peer-reviewe

Triple-loop learning and conversing with reality

Purpose: Three levels of learning developed by Gregory Bateson in the tradition of second-order cybernetics have in-part been translated in terms of double-loop and triple-loop learning, particularly in the tradition of systems thinking. Learning III and triple-loop learning have gained less popularity since they deal with less tangible issues regarding virtues of wisdom and justice respectively. This paper provides a learning device – the systems thinking in practice heuristic which helps to retrieve the cybernetic concern for wisdom in association with an often forgotten systems concern for real-world power relations. Approach: Using ‘conversation’ as a metaphor the heuristic is introduced based on three orders of conversation. Drawing on ideas of systemic triangulation, another heuristic device – the systemic triangulator – is used to surface issues of power in the three orders of conversation. Some manifestations in using the systems thinking in practice heuristic for supporting postgraduate systems learning are demonstrated. Findings: Some key complementarities between conventionally opaque cybernetic issues of wisdom and systems issues of power are revealed, and used proactively to explore more effective coaching of systems thinking in practice. Implications: Cybernetics and Systems thinking may benefit from being grounded more in understanding, engaging with, and transforming social realities. The heuristics provide practical experiential and meaningful learning through conversation, and more social premium for the study of cybernetics and systems thinking. Originality/value: The heuristics – systems thinking in practice, and the systemic triangulator provides an innovative cyber-systemic space for learning and action

The 2010 Interferometric Imaging Beauty Contest

We present the results of the fourth Optical/IR Interferometry Imaging Beauty Contest. The contest consists of blind imaging of test data sets derived from model sources and distributed in the OI-FITS format. The test data consists of spectral data sets on an object "observed" in the infrared with spectral resolution. There were 4 different algorithms competing this time: BSMEM the Bispectrum Maximum Entropy Method by Young, Baron & Buscher; RPR the Recursive Phase Reconstruction by Rengaswamy; SQUEEZE a Markov Chain Monte Carlo algorithm by Baron, Monnier & Kloppenborg; and, WISARD the Weak-phase Interferometric Sample Alternating Reconstruction Device by Vannier & Mugnier. The contest model image, the data delivered to the contestants and the rules are described as well as the results of the image reconstruction obtained by each method. These results are discussed as well as the strengths and limitations of each algorithm.Comment: To be published in SPIE 2010 "Optical and infrared interferometry II

The Technical Standardization Ecosystem and Institutional Decision Making: The Case of Intellectual Property Rights Policies

In this paper, we analyze decision making on Intellectual Property Rights (IPR) policies in the standardization ecosystem. While a large literature has studied IPR policies of Standard Developing Organizations (SDOs), we contribute a more rigorous analysis of how these IPR policies are shaped by the interdependencies between SDOs and between SDOs and a variety of stakeholders. While SDO stakeholders often have opposing policy preferences, they are tied together by non-generic complementarities and a joint interest in the overall performance of the standardization system, which are constitutive characteristics of an ecosystem. The standardization ecosystem is characterized by widely shared institutional norms, which – in the field of IPR – result in the preponderance of what we call a “Baseline Policy”. SDOs’ positions in the ecosystem contributes to explain where in the ecosystem institutional innovations going beyond the Baseline Policy are more likely to arise. We analyze different mechanisms of transmission of such novel practices, such as emulation and precedent

Salience games : private politics when public attention is limited

We develop a theoretical model in which an industry and NGO play salience games - they act strategically to influence public attention to social impacts in the sector. Salience stimulates extra donations for the NGO, and thus firms have incentives to hide the damage they do to avoid public attention. How can an NGO design its mission (how to divide income between campaigning and other projects, and what sorts of campaigns to run) to thrive in such a setting? We show that when public attention is scarce, a greater campaign orientation induces industry to invest in greater obfuscation, starving the NGO of funds. The NGO in turn strategically biases its mission away from campaigns, and in favor of sector-wide versus firm-specific campaigns, but not by as much as a welfare-motivated planner would want. When public attention is avoided by a mixture of substantive and symbolic action, we show that a greater weight on the former induces the NGO to become more campaign-oriented, with social damage lower

Impaired identification of impoverished animate but not inanimate objects in adults with high-functioning autism spectrum disorder

The ability to identify animate and inanimate objects from impoverished images was investigated in adults with high-functioning autism spectrum disorder (HFA) and in matched typically developed (TD) adults, using a newly developed task. Consecutive frames were presented containing Gabor elements that slightly changed orientation from one frame to the next. For a subset of elements, the changes were such that these elements gradually formed the outline of an object. Elements enclosed within the object's outline gradually adopted one and the same orientation, outside elements adopted random orientations. The subjective experience was that of an object appearing out of a fog. The HFA group required significantly more frames to identify the impoverished objects than the TD group. Crucially, this difference depended on the nature of the objects: the HFA group required significantly more frames to identify animate objects, but with respect to the identification of inanimate objects the groups did not differ. The groups also did not differ with respect to the number and type of incorrect guesses they made. The results suggest a specific impairment in individuals with HFA in identifying animate objects. A number of possible explanations are discussed

« Je ne sais pas si cette épidémie d’Ebola était si imprévisible que cela… »

On le sait, Médecins Sans Frontières aura été en première ligne dans la lutte contre Ebola. Ce que l’on sait moins, c’est qu’en matière épidémiologique, l’ONG dispose d’une cellule dédiée : Épicentre. Médecin généraliste formé à l’épidémiologie, Emmanuel Baron s’est engagé avec Médecins Sans Frontières de nombreuses années sur le terrain et au siège avant de rejoindre Épicentre dont il est aujourd’hui le directeur