Hardy inequalities in globally twisted waveguides

We establish various Hardy-type inequalities for the Dirichlet Laplacian in perturbed periodically twisted tubes of non-circular cross-sections. We also state conjectures about the existence of such inequalities in more general regimes, which we support by heuristic and numerical arguments.Comment: 18 pages, 1 figur

Analyse spectrale des guides d'ondes "twistés"

In this thesis we study the spectral properties of perturbed 3D quantum waveguides (tubes). We mainly consider two types of perturbation:The first type is a geometric perturbation. More precisely, we study the Laplace operator with Dirichlet boundary conditions defined in a twisted tube. The twist that we consider is a constant one that has been locally perturbed by a function of same sign (a repulsive twist). The second type of perturbation is done by changing locally the boundary conditions. In fact, we study the Laplacian operator with Dirichlet conditions everywhere on the boundary of the tube except on a bounded part where we consider the Neumann conditions. In one hand we study the straight tubes (with no geometric perturbations) to figure out the effect of perturbation that occurred in the boundary conditions. In the other hand we study the twisted tubes to establish a comparison between the opposite effects of these two types of perturbation (the geometric one and the change that we imposed on the boundary conditions).Dans cette thèse, nous étudions les propriétés spectrales des guides d'onde quantiques tridimensionnels (les tubes) perturbés. Nous considérons, principalement deux types différents de perturbation : Dans le premier type, il s’agit de la perturbation d’une déformation géométrique. Plus précisément, nous étudions l’opérateur de Laplace de Dirichlet défini dans un tube déformé à l’aide d’une torsion constante perturbée localement par une fonction de même signe (torsion répulsive).Le deuxième type de perturbation consiste à changer localement les conditions aux bords imposées sur la frontière du guide d’onde. En effet, il s’agit de l’étude du Laplacien avec des conditions aux bords mixtes.Nous imposons des conditions aux bords de Dirichlet par tout sur la frontière du guide d’onde, sauf sur une partie bornée où nous considérons des conditions aux bords de Neumann. D’une part, nous examinons les tubes droits (sans déformations géométriques) dans le but de comprendre l’effet de la perturbation des conditions aux bords. D’autre part, nous étudions les tubes torsadés afin d’établir une comparaison entre les effets opposés des deux perturbations (géométrique et des conditions aux bords)

Osteolytic clear cell meningioma of the petrous bone occurring 36 years after posterior cranial fossa irradiation: Case report

Objective and importance While bone invasion and hyperostosis are frequent phenomena in meningiomas, primary intraosseous meningiomas are rare and their occurrence in the skull base is an extraordinary exception. Moreover, radiation-induced meningiomas represent a unique clinical dilemma given the fact that patients with these tumors had often received a prior full course of radiotherapy. Clinical presentation A 42-year-old man presented with a 3-month history of progressively worsening facial asymmetry. His medical history was consistent for a posterior cranial fossa irradiation at the age of 6 years for a non-confirmed brain stem tumor. On admission his Karnofsky performance status was graded as 50% and his neurological examination showed a complete right facial nerve paralysis and hearing impairment. Computed tomography and magnetic resonance imaging demonstrated an osteolytic tumor invading the whole right petrous bone without intracranial involvement. Intervention As the tumor reached the external auditory canal, a tissue sample was obtained locally. Pathological examination of the lesion identified a grade II clear cell meningioma and the patient was consequently addressed for an intensity modulated radiation therapy. His condition remained unchanged till the most recent follow-up examination, 8 months later. Conclusions To the best of our knowledge, a radiation induced osteolytic clear cell meningioma of the petrous bone has not been previously reported. As little literature exists regarding the use of adjuvant therapies for these tumors, intensity modulated radiation therapy remains an attractive treatment option in case of pervious irradiation and general status alteration

Patients’ experience sharing with online social media communities : a bottom-of-the-pyramid perspective

PURPOSE : Despite having inadequate resources, highly impoverished patients tend to seek and share health information over social media groups to improve each other’s well-being. This study aims to focus on access to health-care information for such patients and aims to provide an understanding of how online health-care communities (OHCs), as transformative service mediators, can be platforms for patients with chronic and nonchronic health conditions to share their experiences in a base-of-the-pyramid (BOP) context. DESIGN/METHODOLOGY/APPROACH : A large-scale survey among 658 respondents was conducted in a very low-income country. Structural equation modeling was used to test the hypotheses. FINDINGS : A model of patients’ experience sharing (PES), motivations and consequences for health-care services are introduced and tested. The result supports the PES model for patients with chronic health conditions, showing that utilitarian, hedonic and social value dimensions directly influence PES and indirectly influence patients’ continuance intention with OHCs and patient efforts. However, a mediating effect of PES was found only between the value dimensions and patients’ efforts. A negative moderation effect of medical mistrust was found in the relationship between utilitarian value and PES for both chronic and nonchronic patient groups. ORIGINALITY/VALUE : This study is a pioneering attempt to develop and test a PES model in a BOP market.https://www.emerald.com/insight/publication/issn/0887-6045hj2023Marketing Managemen

Study of the catalytic wet air oxidation of p-hydroxybenzoic acid on a fresh ruthenium catalyst supported by different oxides

The catalytic wet air oxidation (CWAO) of p-hydroxybenzoic acid (p-HBA) was conducted in a batch reactor at 140 °C, and at a total air pressure of 50 bar over Ru-based catalysts. Four materials were selected as supports – TiO2, CeO2–TiO2, ZrO2–TiO2, and La2O3–TiO2 – all of which had mesopores in their texture and pollutant adsorption capacities. The supports were prepared by the sol-gel method, and then impregnated with 3 wt% of Ru precursor. Such characterization techniques as N2-sorption, XRD, XPS, H2–TPR, NH3-TPD, TEM, and HAADF-STEM were used to analyze the different solids. The correlation between catalytic activities and physicochemical properties was discussed. A significant specific surface area (SBET), a large amount of surface-active oxygen, and Lewis acidity sites were observed on cerium-containing catalysts (Ru/CeTi). Fresh Ru catalysts containing cerium showed higher activity than Ru/TiO2, Ru/ZrTi, and Ru/LaTi catalysts. It is assumed that the acidic sites and surface oxygen trap the p-HBA molecule, thus increasing the catalytic properties of the Ru particles which interact with the surface oxygen through the cerium redox process (Ce3+/Ce4+). As the presence of cerium increases surface-active oxygen, it inhibits the deposition of carbon on the surface of the Ru catalyst. The pseudo-second order (PSO) model adequately described the kinetic data of the p-HBA oxidation reaction using Ru catalysts.Peer ReviewedPostprint (published version

La métaplasie malpighienne dans le carcinome papillaire de la thyroïde

Introduction : la métaplasie malpighienne est rare au niveau de la thyroïde. Elle peut être associée à un processus pathologique tumoral ou inflammatoire.Matériels et méthodes : les auteurs se proposent de rapporter une observation de métaplasie malpighienne de la thyroïde associée à un carcinome papillaire diagnostiqué au service d’Anatomie et de Cytologie pathologiques du CHU Farhat Hached de Sousse et d’en discuter la pathogénie de cette métaplasie, ses circonstances de survenue et ses difficultés diagnostiques.Résultats : il s’agissait d’une fille âgée de 9 ans ayant consulté pour un nodule de la thyroïde. Une cytoponction de ce nodule était pratiquée et avait montré la présence de cellules tumorales d’un carcinome papillaire. Une thyroïdectomie totale avec curage triangulaire fonctionnel a été réalisée. L’examen anatomo-pathologique de la pièce a confirmé la présence d’un carcinome papillaire de la thyroïde avec présence au voisinage de la tumeur de plages de cellules malpighiennes d’allure non tumorale.Conclusion : bien que rare, la métaplasie malpighienne peut se voir dans la thyroïde. Elle doit être distinguée d’un carcinome épidermoïde de la thyroïde par la recherche systématique, devant tout foyer de métaplasie malpighienne, des signes de malignité.Mots clés : métaplasie malpighienne, carcinome papillaire, glande thyroïde

The gamification as a tool to increase employee skills through interactives work instructions training

Lean practices, because of their importance and effects on production processes, have contributed significantly to changes in the processes where they are successfully implemented, promoting the initiation of a process of cultural change within the organizations that have resulted in best practices in search of excellence operational. The combination of lean practices and the process of gamification enabled us to explore aspects related to the teaching-learning process through interactive and collaborative methods to boost knowledge of the teams and, so to speak, the organization. The case study of this work intends to share practical results of the adoption of the gamification processes, which allowed, through the integration and involvement of the work teams, the development of automated document control systems and self-assessment processes in the scope of the productive processes, as well as interactive training, as a component associated to the lean practices adopted by the company object of this study, and its contributions to the results of the organization in the scope of quality management, production, and management teams.This research has been carried out as part of the Manufacturing Network 4.0 project, as funded by the Technicolor P&D program in partnership with FPF-Tech. The authors wish to thank the project partners for facilitating this work

Primary lymphoepithelial carcinoma of the parotid gland in a North African woman

Lymphoepithelial carcinoma of the salivary glands is a rare neoplasm that is characterized by a non-neoplastic lymphocytic infiltration associated with an epithelial proliferation. It involves mainly the parotid gland. Racial and geographical factors contribute to the pathogenesis of this tumor. We report a case of a 70-year old woman from a non-endemic area who presented with several months history of swelling in the parotid region. Magnetic resonance imaging showed a parotid mass suggestive of a pleomorphic adenoma. The diagnosis of lymphoepithelial carcinoma of the parotid gland was performed on the surgical specimen. A primitive nasopharyngeal carcinoma was ruled out by random biopsies of the nasopharynx mucosa. The Epstein-Barr virus (EBV) was absent in neoplastic cells. We insist that, even in non-endemic areas and when clinical and radiological characteristics are not suggestive of malignancy, intra-operative frozen section analysis should be used in order to ensure the appropriate treatment

Customer brand engagement during service lockdown

While customer brand engagement (CBE) research has advanced important insight, most studies to-date explore CBE under regular, free-market conditions, yielding an important knowledge gap regarding its manifestation under less regular conditions, including disaster/pandemics. We therefore explore CBE with essential/non-essential service during COVID-19-prompted citizen lockdown. Based on a review, we develop a framework of lockdown-based CBE with essential/non-essential service interactions, which are conceptualized by their respective capacity to meet differing needs in Maslow’s hierarchy. We view lockdown-based essential/non-essential service interactions to differentially impact CBE, as summarized in a set of Propositions. The framework depicts lockdown-based essential/non-essential service interactions and their respective impact on CBE. We propose two essential service modes (i.e., socially distant/platform-mediated interactions) and two non-essential service modes (i.e., service closure/platform-mediated interactions), which we hypothesize to differently affect CBE. Moreover, we view the associations between our lockdown-based service modes and CBE to be moderated by customers’ regulatory focus (i.e., promotion/prevention), as formalized in our Propositions. Given our focus on lockdown-based CBE, this paper adds unique insight to the literature. It also raises ample opportunities for further study, as outlined. This research yields important managerial implications, including the suggested adoption of differing tactics/strategies to leverage promotion/prevention-focused customers’ brand engagement during lockdown. By exploring the effects of lockdown-based essential/non-essential service modes on promotion/prevention-focused customers’ brand engagement, this paper adds novel insight