Symmetry Conditions for Non-reciprocal Light Propagation in Magnetic Crystals

Recent studies demonstrated the violation of reciprocity in optical processes in low-symmetry magnetic crystals. In these crystals the speed of light can be different for counter-propagating beams. Correspondingly, they can show strong directional anisotropies such as direction dependent absorption also called directional dichroism[S. Bord\'acs et al., Nat. Phys. 8, 734 (2012); M. Saito et al., J. Phys. Soc. Jpn. 77, 013705 (2008)]. Based on symmetry considerations, we identify the magnetic point groups of materials which can host such directional anisotropies and also provide a list of possible candidate materials to observe these phenomena. In most of these cases, the symmetry of the crystal allows directional anisotropy not only for optical processes but also for the propagation of beams of particles and scalar waves. We also predict new types of directional optical anisotropies -- besides the optical magnetoelectric effect and the magnetochiral dichroism investigated so far -- and specify the magnetic point groups of crystals where they can emerge.Comment: Overall revisio

Analysis of an epidemic model with awareness decay on regular random networks

The existence of a die-out threshold (different from the classic disease-invasion one) defining a region of slow extinction of an epidemic has been proved elsewhere for susceptible-aware-infectious-susceptible models without awareness decay, through bifurcation analysis. By means of an equivalent mean-field model defined on regular random networks, we interpret the dynamics of the system in this region and prove that the existence of bifurcation for of this second epidemic threshold crucially depends on the absence of awareness decay. We show that the continuum of equilibria that characterizes the slow die-out dynamics collapses into a unique equilibrium when a constant rate of awareness decay is assumed, no matter how small, and that the resulting bifurcation from the disease-free equilibrium is equivalent to that of standard epidemic models. We illustrate these findings with continuous-time stochastic simulations on regular random networks with different degrees. Finally, the behaviour of solutions with and without decay in awareness is compared around the second epidemic threshold for a small rate of awareness decay

On randomized stopping

A general result on the method of randomized stopping is proved. It is applied to optimal stopping of controlled diffusion processes with unbounded coefficients to reduce it to optimal control problem without stopping. This is motivated by recent results of Krylov on numerical solutions to the Bellman equation

Frais de gestion de fortune: impact des nouvelles dipositions légales envers les acteurs de la prévoyance professionnelle

A l’heure où la sécurité sociale dépendait du bon vouloir des descendances et d’oeuvres charitables le système des trois piliers s’est mis en place au rythme du 20ème siècle. Plus précisément, la prévoyance professionnelle a connu ses premiers jours en 1985 dans le but de maintenir un niveau de vie décent aux personnes nécessiteuses. La loi sur la prévoyance et ses deux ordonnances répondent à ces attentes. Malgré un bon encadrement, plusieurs modifications ont été entreprises pour permettre une évolution et une meilleure adaptation aux nouvelles contraintes qui surviennent. La réforme de 2010 en est la preuve, celle-ci a su modifier et réadapter des articles afin de permettre une plus grande transparence sur ce marché. En 2012, le marché du deuxième pilier est composé de 2073 institutions de prévoyance pour une fortune globale d’environ 700 milliards de francs suisses. Les frais de gestion de fortune quant à eux s’élèvent à 853 millions, soit 0.14% de la fortune globale. Des frais qui d’après plusieurs cabinets de conseil se situent bien en-dessous des vrais montants. Une partie de la réforme 2010 a donc mis en place des mesures pour faire apparaître ces frais et permettre une plus grande visibilité des frais encourus par les institutions de prévoyance. Le but de ce travail est de vérifier que les leviers mis en place ont bien été respectés et qu’ils ont apporté des solutions à cette problématique. Dans ces principales lignes, en plus de devoir faire figurer le deuxième et le troisième niveau liés aux placements collectifs et aux produits structurés les caisses doivent dès à présent : déterminer un ratio de frais de gestion de fortune global, déterminer pour chaque placement collectif un indicateur des frais en francs suisses, calculer le taux de transparence et indiquer dans l’annexe aux comptes les placements considérés comme non transparents en matière de frais. Ces directives ont pour la plupart été correctement mises en place dans les comptes 2013. Néanmoins, certaines recommandations permettraient une meilleure lecture des comptes. Pour cela, il faudrait davantage détailler les frais de chaque placement collectif, indiquer la performance liée à chaque placement, exiger aux caisses d’expliciter dans l’annexe aux comptes certaines décisions de placement et interdire les placements dans des produits non transparents. Ces recommandations, au-delà du point de vue monétaire, apporteraient une plus grande protection aux investisseurs et veilleraient indirectement au bon fonctionnement des marchés financiers. Les années à venir nous donneront plus d’informations sur l’impact réel de ces directives car pour l’heure la réforme « prévoyance professionnelle 2020 » est déjà au centre des débats

Causes and Circumstances of Red Mud Reservoir Dam Failure In 2010 at MAL Zrt Factory Site in Ajka, Hungary

The red mud reservoir failure in Ajka, Hungary has claimed 10 lives and cost millions of dollars in damages. Immediately after emergency measures investigations started to shed light on causes and circumstances. The authors performed an extensive desktop study of about 20 thousand pages reaching back to the 1970s, when the facility has been designed. Beside this study the dam and its area have gone through series of site investigations, from drilling to CPTu testing and laboratory testing. The information so collected resulted in the following conclusion. Contributing factors to this substantial dam failure included poor siting of the facility, partly on top of a diverted creek bed and marshy area; design faults when calculating safety reserves, as well as basic stability at designed maximum reservoir load. Construction technology has not been controlled; its foundation was built unprofessionally. The negligence of regulators at licensing, at commissioning, as well as at the periodic safety reviews. There was no geotechnical monitoring plan, it was considered to be unnecessary. External negative factors further converged with these deficiencies. The frequency of smaller earthquakes was significantly higher in the accident-preceding year than during the previous ten years. Precipitation was unusual, its level during the accident-preceding half year reached an incidence frequency of 3000 years! Heightened groundwater level saturated the clay base surface of the reservoir already weakened by cat-ion exchanges due to high alkalinity of red mud – on sloping surface. The slurry walls built around the reservoir, from environmental protection purpose, have intensified this process. Strong wind gusts shifting direction pressured the dam walls during the day of accident

Linking an integrated framework with appropriate methods for measuring QoE

Quality of Experience (QoE) has recently gained recognition for being an important determinant of the success of new technologies. Despite the growing interest in QoE, research into this area is still fragmented. Similar - but separate - efforts are being carried out in technical as well as user oriented research domains, which are rarely communicating with each other. In this paper, we take a multidisciplinary approach and review both user oriented and technical definitions on Quality of Experience (including the related concept of User Experience). We propose a detailed and comprehensive framework that integrates both perspectives. Finally, we take a first step at linking methods for measuring QoE with this framework

Marsov vepar u zemlji Panoniji – prijepor između Marka Pitačića i Petra Beregszászija (?)

Appena nominato, il nuovo vescovo della diocesi di Győr, György Draskovich, aveva convocato il sinodo per l’estate dell’anno 1579, nella città di Szombathely. Nel primo giorno del sinodo, su invito del nuovo vescovo, il gesuita croato Marcus Pitačić pronunciò un discorso che trattava dei criteri per divenire prete, della morale che la comunità esigeva da parte del clero e dell’istituzione del celibato, attaccando e confutando le relative dottrine dei protestanti. La reazione al discorso di Pitačić da parte dei protestanti non arrivò subito ma si fece aspettare per un decennio e mezzo. Nel 1585 uscì il libro di Péter Beregszászi, Apologia pro ecclesiis reformatis, actis impiis Synodi Sabariensis opposita, che contiene sia l’Oratio di Pitačić sia la risposta di Beregszászi, in cui egli smentisce punto per punto le asserzioni del gesuita. Il fatto che, due anni dopo, venne pubblicato a Basel il volume De controversiis religionis hoc seculo motis adversaria quaedam scripta, in quibus utriusque partis dissidentium argumenta, ad Scripturae divinae canonem explorantur et Iesuitis potissimum respondetur, mostra l’importanza dei due testi dell’Apologia che, assieme ad alcuni libelli apparsi negli anni ’80, viene interamente riproposta nel detto volume. A seguito della breve presentazione riassuntiva della vita di Pitačić, l’articolo offre un quadro sintetico della sua controversia con Beregszászi, ricca di argomentazioni e di mezzi retorico-linguistici che servivano al predicatore protestante per rendere ridicoli i gesuiti e contestare l’autenticità delle parole del suo avversario.Novoizabrani biskup dijeceze Győr Juraj Drašković odmah po imenovanju sazvao je ljetnu sinodu za godinu 1579. u gradu Sambotelu. Prvoga dana sinode, na poziv novoga biskupa, hrvatski isusovac Marko Pitačić održao je govor o kriterijima za postajanje svećenikom, o moralnosti koju društvo zahtijeva od klera i o instituciji celibata, napadajući i osporavajući vezane protestantske doktrine. Odgovor protestanata na Pitačićev govor nije stigao odmah – trebalo ga je čekati desetljeće i pol. Godine 1585. izašla je knjiga Petra Beregszászija Apologia pro ecclesiis reformatis, actis impiis Synodi Sabariensis opposita, koja je sadržavala i Pitačićev govor i Beregszászijev odgovor, u kojemu je točku po točku pobijao Pitačićeve tvrdnje. Činjenica da je dvije godine potom u Baselu objavljen volumen De controversiis religionis hoc seculo motis adversaria quaedam scripta, in quibus utriusque partis dissidentium argumenta, ad Scripturae divinae canonem explorantur et Iesuitis potissimum respondetur ukazuje na važnost dvaju tekstova Apologije, koji su ondje iznova objavljeni zajedno s drugim knjižicama iz 1580-ih. U članku se kratko prikazuje Pitačićev život, nakon čega se daje sintetička slika njegova prijepora s Beregszászijem, bogatog argumentacijom te retoričkim i jezičnim sredstvima koja su protestantskome propovjedniku trebala poslužiti kako bi ismijao isusovce i opovrgao autentičnost protivnikovih riječi

A Novel Contactless Technique to Measure Water Waves Using a Single Photon Avalanche Diode Detector Array

Commonly deployed measurement systems for water waves are intrusive and measure a limited number of parameters. This results in difficulties in inferring detailed sea state information while additionally subjecting the system to environmental loading. Optical techniques offer a non-intrusive alternative, yet documented systems suffer a range of problems related to usability and performance. Here, we present experimental data obtained from a 256 × 256 Single Photon Avalanche Diode (SPAD) detector array used to measure water waves in a laboratory facility. 12 regular wave conditions are used to assess performance. Picosecond resolution time-of-flight measurements are obtained, without the use of dye, over an area of the water surface and processed to provide surface elevation data. The SPAD detector array is installed 0.487 m above the water surface and synchronized with a pulsed laser source with a wavelength of 532 nm and mean power <1 mW. Through analysis of the experimental results, and with the aid of an optical model, we demonstrate good performance up to a limiting steepness value, ka, of 0.11. Through this preliminary proof-of-concept study, we highlight the capability for SPAD-based systems to measure water waves within a given field-of-view simultaneously, while raising potential solutions for improving performance

Techniques on vertical ridge augmentation: Indications and effectiveness.

Vertical ridge augmentation techniques have been advocated to enable restoring function and esthetics by means of implant-supported rehabilitation. There are three major modalities. The first is guided bone regeneration, based on the principle of compartmentalization by means of using a barrier membrane, which has been demonstrated to be technically demanding with regard to soft tissue management. This requisite is also applicable in the case of the second modality of bone block grafts. Nonetheless, space creation and maintenance are provided by the solid nature of the graft. The third modality of distraction osteogenesis is also a valid and faster approach. Nonetheless, owing to this technique's inherent shortcomings, this method is currently deprecated. The purpose of this review is to shed light on the state-of-the-art of the different modalities described for vertical ridge augmentation, including the indications, the step-by-step approach, and the effectiveness