Flat bands of periodic graphs

We study flat bands of periodic graphs in a Euclidean space. These are infinitely degenerate eigenvalues of the corresponding adjacency matrix, with eigenvectors of compact support. We provide some optimal recipes to generate desired bands, some sufficient conditions for a graph to have flat bands, we characterize the set of flat bands whose eigenvectors occupy a single cell and we compute the list of such bands for small cells. We next prove that flat bands are rare and vanish under arbitrarily small perturbations by periodic potentials. Additional folklore results are proved and many questions are still open.Comment: 25 pages, 19 figure

Impact des dépenses sociales sur la croissance par habitant ; Cas du Maroc

Ce travail étudie le rôle du capital humain dans une croissance endogène, il analyse l’effet du capital humain et le taux d’activité sur la croissance économique au Maroc, les études ont montré que l’éducation et la santé ont une relation directe et indirect, positive et significative dans la croissance économique du pays et dans la croissance par habitant en particulier. Le taux d’activité lié au chômage et à la population a aussi une relation directe avec la croissance économique. Le Maroc, depuis les années quatre-vingt, a connu des réformes ambitieuses dans le secteur de l’éducation comme la Charte Nationale de l’Education et de la Formation (CNEF) lancée en 1999, la vision stratégique (2015-2030) aussi bien pour le secteur de la santé (la loi n` 09-30 relative à la protection sociale) ce qui a demandé des énormes dépenses. Ce travail étudie l’impact des dépenses sociales et le taux d’activité sur le PIB par habitant au Maroc, avec la méthode de Moindre Carré Ordinaire (MCO), en utilisant les données de la période 1990 à 2021

Entrepreneurship and Sustainability: The Need for Innovative and Institutional Solutions

The role of innovation and institutional quality for achieving sustainability are important issues tackled by current sustainable development debates, particularly in developing countries. Using a modified environmental Kuznets curve model, the present study improves our understanding of the critical roles of innovation, institutional quality, and entrepreneurship in structural change toward a sustainable future for Africa. Our empirical results show that formal and informal entrepreneurship are conducive to reduced environmental quality and sustainability in 17 African countries however informal entrepreneurship contributes more than formal entrepreneurship to this environmental degradation. The relationship between entrepreneurship and sustainable development turns strongly positive in the presence of high levels of innovation and institutional quality. This study contributes to this emerging research strand by clarifying the conditions that allow African countries to move toward more sustainable economies. Our results highlight the important roles played by innovation and institutions for achieving sustainability in Africa

The Casimir force in noncommutative Randall-Sundrum models

In this paper we study the effect of spacetime noncommutativity in the 5-dimensional Randall-Sundrum brane worlds on the Casimir force acting on a pair of parallel plates. We show that the presence of a noncommutative scale length affects the nature of the Casimir force for small plate separation. Using accurate experimental bounds for the Casimir force in parallel plate geometry, we find an upper bound for the noncommutative cutoff of the order of $10^{3}$ TeV, and that the size of the interbrane distance in RSI model is approximately given by $kR\lesssim20.5$ and $kR\lesssim18.4$ for $k=10^{19}$ GeV and $k=10^{16}$GeV, respectively.Comment: 20 pages, 5 figures, accepted for publication in Phys. Rev.

Smartphone and Surgery, Reality or Gadget?

Surgical care is an essential component of health care. This basic universal right is not available to everyone. Indeed, countries with low economic resources suffer from a lack of access to surgical care and the most developed countries will have to reduce the cost of health care to ensure the sustainability of provided care quality. New communication technologies have invaded the field of health and have led to the development of a new concept of mobile health. The purpose of this paper is to answer the following question: Can these new tools, and in particular the Smartphone, remedy, even partially, the lack of health care in poor countries and reduce the cost of health care in rich countries? New communication tools, led by the Smartphone, have the capacity to capture, store, retrieve and transmit data to provide instant and personalized information to individuals. This information could be a key element in health systems and can contribute to monitoring health status and improving patient safety and care quality. Mobile telephony via applications and connected objects can facilitate the pre-, intra- and post-operative management of patients. These mobile systems also facilitate the collection and transmission of data. This will allow better analysis of this data and will greatly pave the way to the introduction of artificial intelligence in medicine and surgery. The Smartphone can be used as an important tool for both, diagnosis care and surgical training. Surgeons must adapt their equipment to local resources while respecting safety standards. Covid-19 has put health systems around the world under severe strain. Decision-makers are being forced to make adjustments. The long-vaunted digital health is becoming a reality and a necessity. Healthcare authorities and strategy specialists face challenges in terms of disease prevention and therapy, as well as in terms of health economics and management

Serious Games at the service of student’s integration into the work sector: Case of computer science engineering students

Students develop a big commitment personally and invest financially to pursue their education and get the degree that opens many gateways for them, but what if the degrees don’t match the skills required by most employers? As time has changed, employability is based on knowledge and several abilities such as soft skills, communication, leadership, creative and critical thinking. It is hard for universities to keep track of all these changes and, at the same time, the technological advancements, the hard facts and the skills of most of the disciplines. Our research aims to study the needs requested the most by employers. To achieve that, we started with a survey with some laureates and multiple interviews with different recruiters to identify their requirements. We can define the training students need to have before integrating the job market, ease their insertion, and make their integration successful