Kappa vacua: A generalization of the thermofield double state

We elaborate more on $\kappa$-mode, a mode that was found by a combination of Rindler modes in the right and left Rindler wedges with opposite sign norms. We find a relation between different kappa vacua, similar to the Minkowski-Rindler vacua relation. Then, inspired by the fact that the thermofield double state is an expression for the Minkowski vacuum in terms of the Rindler vacuum, we may interpret our $\kappa$-vacuum as a generalized non-thermofield double state. A general $\kappa \neq1$ vacuum, in contrast to the well-known case of the Minkowski vacuum, is no longer thermal when reduced to a specific Rindler wedge.Comment: 25 pages; Ver2: an appendix added, more clarification in section 5; Ver3: more clarification in section

Comparison of Periodontal Status in Gingival Oral Lichen Planus Patients and Healthy Subjects

Background and Objective. Oral lichen planus (OLP) is a common chronic mucocutaneous disease. OLP can occur in different oral sites such as gingiva. The purpose of study was to evaluate the periodontal status of OLP patients with desquamative gingivitis (DG) and compare it with that of healthy control. Methods. This study was case-control. 32 patients with gingival OLP as a case group and 32 healthy subjects as a control group were selected. The periodontal status of all subjects including plaque index (PI), bleeding on probing (BOP), and clinical attachment level (CAL) was evaluated in both groups. Finally data were analyzed by t-test. Results. The mean values of periodontal parameters were observed to be higher in case group compared with control group, and this was significant (P < 0.05). Conclusion. Our results showed that periodontal status is worse in gingival OLP if compared with healthy controls

On Consistent Kaluza-Klein-Pauli Reductions

Kaluza-Klein dimensional reduction is an indispensable ingredient of the theoretical physics, since, M-theory and superstring theories are consistent in eleven and ten dimensions and thus, to make a connection to our four-dimensional space-time physics, it is crucial to use this mechanism. Dimensional reduction on a general coset space such as a sphere, introduced by Pauli, is more subtle that that of a group manifold reduction, introduced by DeWitt, including the circle reduction of Kaluza and Klein. While there is a group-theoretic argument for the consistency of the latter, there is no such an argument for the former, hence, besides the exceptional cases, all Pauli reductions may be inconsistent. We study an uplift ansatz for two specific truncations of gauged STU supergravity. This theory itself is an important truncation of the renowned N = 8, gauged SO(8) supergravity in four dimensions. We consider two truncations of the former theory, named as 3+1 and 2+2, due to the way of truncations of their gauge fields. We find the uplift ansätze for the metric and the four-form field strength in these cases. We consider two theories and explore the possibility of their consistent Pauli S^2 reductions. First, minimal supergravity in five dimensions, and second, the Salam-Sezgin theory. We use the Hopf reduction technique in both cases, and by that, we show while it is not possible to perform a consistent reduction of the former, there is a consistent Pauli reduction of the latter, and by this construction, we can recover the result of Gibbons-Pope in 2003. In other words, we can provide a group theoretical argument for their work. To make the latter case happen, we find a new higher dimensional origin for the Salam-Sezgin theory, at least in the bosonic sector

Using the Fringe Field of MRI Scanner for the Navigation of Microguidewires in the Vascular System

Le traitement du cancer, la prévention des accidents vasculaires cérébraux et le diagnostic ou le traitement des maladies vasculaires périphériques sont tous des cas d'application d'interventions à base de cathéter par le biais d'un traitement invasif minimal. Cependant, la pratique du cathétérisme est généralement pratiquée manuellement et dépend fortement de l'expérience et des compétences de l'interventionniste. La robotisation du cathétérisme a été étudiée pour faciliter la procédure en augmentant les niveaux d’autonomie par rapport à cette pratique clinique. En ce qui concerne ce problème, un des problèmes concerne le placement super sélectif du cathéter dans les artères plus étroites nécessitant une miniaturisation de l'instrument cathéter / fil de guidage attaché. Un microguide qui fonctionne dans des vaisseaux sanguins étroits et tortueux subit différentes forces mécaniques telles que le frottement avec la paroi du vaisseau. Ces forces peuvent empêcher la progression de la pointe du fil de guidage dans les vaisseaux. Une méthode proposée consiste à appliquer une force de traction à la pointe du microguide pour diriger et insérer le dispositif tout en poussant l’instrument attaché à partir de l’autre extrémité n’est plus pratique, et à exploiter le gradient du champ de franges IRM surnommé Fringe Field Navigation (FFN ) est proposée comme solution pour assurer cet actionnement. Le concept de FFN repose sur le positionnement d'un patient sur six DOF dans le champ périphérique du scanner IRM afin de permettre un actionnement directionnel pour la navigation du fil-guide. Ce travail rend compte des développements requis pour la mise en oeuvre de la FFN et l’étude du potentiel et des possibilités qu’elle offre au cathétérisme, en veillant au renforcement de l’autonomie. La cartographie du champ de franges d'un scanner IRM 3T est effectuée et la structure du champ de franges en ce qui concerne son uniformité locale est examinée. Une méthode pour la navigation d'un fil de guidage le long d'un chemin vasculaire souhaité basée sur le positionnement robotique du patient à six DOF est développée. Des expériences de FFN guidées par rayons X in vitro et in vivo sur un modèle porcin sont effectuées pour naviguer dans un fil de guidage dans la multibifurcation et les vaisseaux étroits. Une caractéristique unique de FFN est le haut gradient du champ magnétique. Il est démontré in vitro et in vivo que cette force surmonte le problème de l'insertion d'un fil microguide dans des vaisseaux tortueux et étroits pour permettre de faire avancer le fil-guide avec une distale douce au-delà de la limite d'insertion manuelle. La robustesse de FFN contre les erreurs de positionnement du patient est étudiée en relation avec l'uniformité locale dans le champ périphérique. La force élevée du champ magnétique disponible dans le champ de franges IRM peut amener les matériaux magnétiques doux à son état de saturation. Ici, le concept d'utilisation d'un ressort est présenté comme une alternative vi déformable aux aimants permanents solides pour la pointe du fil-guide. La navigation d'un microguide avec une pointe de ressort en structure vasculaire complexe est également réalisée in vitro. L'autonomie de FFN en ce qui concerne la planification d'une procédure avec autonomie de tâche obtenue dans ce travail augmente le potentiel de FFN en automatisant certaines étapes d'une procédure. En conclusion, FFN pour naviguer dans les microguides dans la structure vasculaire complexe avec autonomie pour effectuer le positionnement du patient et contrôler l'insertion du fil de guidage - avec démonstration in vivo dans un modèle porcin - peut être considéré comme un nouvel outil robotique facilitant le cathétérisme vasculaire. tout en aidant à cibler les vaisseaux lointains dans le système vasculaire.----------ABSTRACT Treatment of cancer, prevention of stroke, and diagnosis or treatment of peripheral vascular diseases are all the cases of application of catheter-based interventions through a minimal-invasive treatment. However, performing catheterization is generally practiced manually, and it highly depends on the experience and the skills of the interventionist. Robotization of catheterization has been investigated to facilitate the procedure by increasing the levels of autonomy to this clinical practice. Regarding it, one issue is the super selective placement of the catheter in the narrower arteries that require miniaturization of the tethered catheter/guidewire instrument. A microguidewire that operates in narrow and tortuous blood vessels experiences different mechanical forces like friction with the vessel wall. These forces can prevent the advancement of the tip of the guidewire in the vessels. A proposed method is applying a pulling force at the tip of the microguidewire to steer and insert the device while pushing the tethered instrument from the other end is no longer practical, and exploiting the gradient of the MRI fringe field dubbed as Fringe Field Navigation (FFN) is proposed as a solution to provide this actuation. The concept of FFN is based on six DOF positioning of a patient in the fringe field of the MRI scanner to enable directional actuation for the navigation of the guidewire. This work reports on the required developments for implementing FFN and investigating the potential and the possibilities that FFN introduces to the catheterization, with attention to enhancing the autonomy. Mapping the fringe field of a 3T MRI scanner is performed, and the structure of the fringe field regarding its local uniformity is investigated. A method for the navigation of a guidewire along a desired vascular path based on six DOF robotic patient positioning is developed. In vitro and in vivo x-ray Guided FFN experiments on a swine model of are performed to navigate a guidewire in the multibifurcation and narrow vessels. A unique feature of FFN is the high gradient of the magnetic field. It is demonstrated in vitro and in vivo that this force overcomes the issue of insertion of a microguidewire in tortuous and narrow vessels to enable advancing the guidewire with a soft distal beyond the limit of manual insertion. Robustness of FFN against the error in the positioning of the patient is investigated in relation to the local uniformity in the fringe field. The high strength of the magnetic field available in MRI fringe field can bring soft magnetic materials to its saturation state. Here, the concept of using a spring is introduced as a deformable alternative to solid permanent magnets for the tip of the guidewire. Navigation of a microguidewire with a viii spring tip in complex vascular structure is also performed in vitro. The autonomy of FFN regarding planning a procedure with Task Autonomy achieved in this work enhances the potential of FFN by automatization of certain steps of a procedure. As a conclusion, FFN to navigate microguidewires in the complex vascular structure with autonomy in performing tasks of patient positioning and controlling the insertion of the guidewire – with in vivo demonstration in swine model – can be considered as a novel robotic tool for facilitating the vascular catheterization while helping to target remote vessels in the vascular system

Effects of repeated hydraulic loads on microstructure and hydraulic behaviour of a compacted clayey silt

Soils used in earth constructions are mostly unsaturated, and they undergo frequent drying-wetting cycles (repeated hydraulic loads) due to changes in climatic conditions or variations of the ground water level, particularly at shallow depths. After compaction, changes in water content can significantly influence the hydromechanical response of the construction material, which therefore has to be assessed for repeated hydraulic loads. This research investigates the effect of such loads on the microstructure and hydraulic behaviour of a silty soil, typically used in the construction of embankments and dykes, with the aim of providing a better understanding of the consequences of drying-wetting cycles on the response of the material over time. Experimental tests were performed to study the impact of drying-wetting cycles on the water retention, hydraulic conductivity and fabric of compacted specimens. Fabric changes are documented to take place even without significant volumetric strains, promoting an irreversible increase in the hydraulic conductivity and a reduction in the capacity to retain water compared to the as-compacted soil. The fabric changes are interpreted and quantified by means of a hydromechanical model, which accounts for the evolving pore size distribution at different structural levels. The proposed model reproduces quite well the microstructural observations, together with the evolution of the water retention behaviour and of the hydraulic conductivit

Evaluating the capability of a critical state constitutive model to predict the collapse potential of loose sand

Many catastrophic flow failures in granular soil slopes are believed to be caused by a rise in pore water pressure associated with substantial loss of soil shear strength. This failure mechanism is known as prefailure instability or static liquefaction. Constant shear (CS) and consolidated undrained (CU) triaxial tests can reproduce stress paths, in which such instability may occur before reaching the failure. In the present study, a previously proposed critical state constitutive model was first used to simulate the behavior of loose saturated sand in CU tests. It was then employed to predict the instability of loose sand subjected to the CS loading. Under such loading, loose dry sand initially experience small volume increase, and then start to contract substantially. In saturated sand, such contractions can lead to the generation of pore water pressure and sudden decrease of shear strength. The capability of the model to predict the onset of the volume contraction and collapse potential of loose dry sand was examined by comparing the model predictions with experimental results of CS tests. The comparison showed that the effect of initial void ratio, consolidation and deviatoric stresses on behavior of loose dry sand can be well predicted by the model

Coupling cyclic and water retention response of a clayey sand subjected to traffic and environmental cycles

Compacted soils used as formation layers of railways and roads continuously undergo water content and suction changes due to seasonal variations. Such variations, together with the impact of cyclic traffic-induced loads, can alter the hydro-mechanical behaviour of the soil, which in turn affects the performance of the superstructure. This study investigates the impact of hydraulic cycles on the coupled water retention and cyclic response of a compacted soil. Suction-monitored cyclic triaxial tests were performed on a compacted clayey sand. The cyclic response of the soil obtained after applying drying and wetting paths was different to that obtained immediately after compaction. The results showed that both suction and degree of saturation are required to interpret the cyclic behaviour. A new approach was developed using (a) a hysteretic water retention model to predict suction variations during cyclic loading and (b) Bishop's stress together with a bonding parameter to predict accumulated permanent strain and resilient modulus. The proposed formulations were able to predict the water retention behaviour, accumulated permanent strains and resilient modulus well, indicating the potential capability of using the fundamentals of unsaturated soils for predicting the effects of drying and wetting cycles on the coupled soil water retention and cyclic response

The bounding effect of the water retention curve on the cyclic response of an unsaturated soil

The water retention properties of soils present in formation layers of roads and railways continuously vary due to repeated traffic loads and periodic rainfall events. This is important because the accumulated deformation and resilient modulus of such soils under cyclic loading are profoundly affected by water retention properties. This paper discusses the cyclic and water retention response of a clayey sand subjected to repetitive cyclic loading and wetting stages. The results show that the accumulated permanent strains and resilient modulus of the tested soil are dependent on the suction level while the main wetting water retention curve of the soil dictates the variation of the suction measured during cyclic loading and wetting. This bounding effect of the water retention curve is found to be dependent on the void ratio where the suction can even increase due to the accumulation of strains under cyclic loading while the degree of saturation increases. This contradicts the suction reduction typically observed with an increase in the degree of saturation. A void ratio dependent water retention model is developed accounting for the observed bounding effect and employed to predict the measured suction during repetitive cyclic loading and wetting. The suction values predicted by the void ratio dependent water retention model are in good agreement with the experimental data. The predicted suctions are then used in semi-empirical formulations to obtain the accumulated permanent strains and resilient modulus. A better correlation between model predictions and experimental data is achieved where the suction values predicted by the void ratio dependent water retention model are used. The results imply that predictive frameworks proposed for the cyclic behaviour of road and railway formation layers require water retention counterparts that incorporate the bounding effect of void ratio on soil water retention curves

Sensitivity-Aware Mixed-Precision Quantization and Width Optimization of Deep Neural Networks Through Cluster-Based Tree-Structured Parzen Estimation

As the complexity and computational demands of deep learning models rise, the need for effective optimization methods for neural network designs becomes paramount. This work introduces an innovative search mechanism for automatically selecting the best bit-width and layer-width for individual neural network layers. This leads to a marked enhancement in deep neural network efficiency. The search domain is strategically reduced by leveraging Hessian-based pruning, ensuring the removal of non-crucial parameters. Subsequently, we detail the development of surrogate models for favorable and unfavorable outcomes by employing a cluster-based tree-structured Parzen estimator. This strategy allows for a streamlined exploration of architectural possibilities and swift pinpointing of top-performing designs. Through rigorous testing on well-known datasets, our method proves its distinct advantage over existing methods. Compared to leading compression strategies, our approach records an impressive 20% decrease in model size without compromising accuracy. Additionally, our method boasts a 12x reduction in search time relative to the best search-focused strategies currently available. As a result, our proposed method represents a leap forward in neural network design optimization, paving the way for quick model design and implementation in settings with limited resources, thereby propelling the potential of scalable deep learning solutions