2,946 research outputs found
Global continuous solutions to diagonalizable hyperbolic systems with large and monotone data
In this paper, we study diagonalizable hyperbolic systems in one space
dimension. Based on a new gradient entropy estimate, we prove the global
existence of a continuous solution, for large and nondecreasing initial data.
Moreover, we show in particular cases some uniqueness results. We also remark
that these results cover the case of systems which are hyperbolic but not
strictly hyperbolic. Physically, this kind of diagonalizable hyperbolic systems
appears naturally in the modelling of the dynamics of dislocation densities
Golgotha, Beirut: A Feminist Memoir of the Port Blast
This partly biographical narrative recounts its narrator’s first-hand, ground-zero experience of the Beirut Port explosion, one of the largest and most destructive in living memory. As the narrator recollects her mother’s distress over the possibility of losing her children post-divorce and her joy at finally obtaining—after a seven-year legal battle—the annulment of an abusive marriage, Beirut Port explodes. The focus shifts to a memorable encounter with another anguished mother who, on the heels of the blast, is hysterical but then completely transformed once reunited with her children. The writer of the memoir culled its material through a number of interviews with the narrator who consented to have her story shared in narrative format, so that the resulting creative nonfiction may contribute to the nascent corpus of gendered writing exploring and interrogating, not only the August 4, 2020 national tragedy in Lebanon, but also the patriarchal system facilitating this calamity
Analysis of models for quantum transport of electrons in graphene layers
We present and analyze two mathematical models for the self consistent
quantum transport of electrons in a graphene layer. We treat two situations.
First, when the particles can move in all the plane \RR^2, the model takes
the form of a system of massless Dirac equations coupled together by a
selfconsistent potential, which is the trace in the plane of the graphene of
the 3D Poisson potential associated to surface densities. In this case, we
prove local in time existence and uniqueness of a solution in H^s(\RR^2), for
which includes in particular the energy space H^{1/2}(\RR^2). The
main tools that enable to reach are the dispersive Strichartz
estimates that we generalized here for mixed quantum states. Second, we
consider a situation where the particles are constrained in a regular bounded
domain . In order to take into account Dirichlet boundary conditions
which are not compatible with the Dirac Hamiltonian , we propose a
different model built on a modified Hamiltonian displaying the same energy band
diagram as near the Dirac points. The well-posedness of the system in
this case is proved in , the domain of the fractional order Dirichlet
Laplacian operator, for
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A review of machine learning techniques in photoplethysmography for the non-invasive cuff-less measurement of blood pressure
Hypertension or high blood pressure is a leading cause of death throughout the world and a critical factor for increasing the risk of serious diseases, including cardiovascular diseases such as stroke and heart failure. Blood pressure is a primary vital sign that must be monitored regularly for the early detection, prevention and treatment of cardiovascular diseases. Traditional blood pressure measurement techniques are either invasive or cuff-based, which are impractical, intermittent, and uncomfortable for patients. Over the past few decades, several indirect approaches using photoplethysmogram (PPG) have been investigated, namely, pulse transit time, pulse wave velocity, pulse arrival time and pulse wave analysis, in an effort to utilise PPG for estimating blood pressure. Recent advancements in signal processing techniques, including machine learning and artificial intelligence, have also opened up exciting new horizons for PPG-based cuff less and continuous monitoring of blood pressure. Such a device will have a significant and transformative impact in monitoring patients’ vital signs, especially those at risk of cardiovascular disease. This paper provides a comprehensive review for non-invasive cuff-less blood pressure estimation using the PPG approach along with their challenges and limitations
Derivation and study of dynamical models of dislocation densities
In this paper, starting from the microscopic dynamics of isolated
dislocations, we explain how to derive formally mean field models for the
dynamics of dislocation densities. Essentially these models are tranport
equations, coupled with the equations of elasticity. Rigorous results of
existence of solutions are presented for some of these models and the main
ideas of the proofs are given
Short time existence and uniqueness in Hölder spaces for the 2D dynamics of dislocation densities
In this paper, we study the model of Groma and Balogh describing the dynamics of dislocation densities. This is a two-dimensional model where the dislocation densities satisfy a system of two transport equations. The velocity vector field is the shear stress in the material solving the equations of elasticity. This shear stress can be related to Riesz transforms of the dislocation densities. Basing on some commutator estimates type, we show thatthis model has a unique local-in-time solution corresponding to any initial datum in the space for and $
Achieving Competence through an Informed Curriculum and Authentic Assessment
Learning Objectives:
- List THREE ways in which health professional training and curriculum can address human capacity for blockade and emergency situations
• Explain the role of academia for training of health professionals competent for practice in blockade and emergency situation
- …