Riemann problems with non--local point constraints and capacity drop

In the present note we discuss in details the Riemann problem for a one--dimensional hyperbolic conservation law subject to a point constraint. We investigate how the regularity of the constraint operator impacts the well--posedness of the problem, namely in the case, relevant for numerical applications, of a discretized exit capacity. We devote particular attention to the case in which the constraint is given by a non--local operator depending on the solution itself. We provide several explicit examples. We also give the detailed proof of some results announced in the paper [Andreainov, Donadello, Rosini, "Crowd dynamics and conservation laws with non--local point constraints and capacity drop", which is devoted to existence and stability for a more general class of Cauchy problems subject to Lipschitz continuous non--local point constraints.Comment: 19 pages, 6 figures. arXiv admin note: substantial text overlap with arXiv:1304.628

Solutions of the Aw-Rascle-Zhang system with point constraints

We revisit the entropy formulation and the wave-front tracking construction of physically admissible solutions of the Aw-Rascle and Zhang (ARZ) " second-order " model for vehicular traffic. A Kruzhkov-like family of entropies is introduced to select the admissible shocks. This tool allows to define rigorously the appropriate notion of admissible weak solution and to approximate the solutions of the ARZ model with point constraint. Stability of solutions w.r.t. strong convergence is justified. We propose a finite volumes numerical scheme for the constrained ARZ, and we show that it can correctly locate contact discontinuities and take the constraint into account

Analysis of the Complications in Patients Undergoing Orthognathic Surgery by Piezosurgery(R): A 13 Years Retrospective Study

Orthognathic surgery is a branch of maxillo-facial surgery increasingly in demand, which deals with the correction of skeletal deformities. The aim of the present study is to identify the most common post-operative complications following orthognathic bimaxillary surgery performed by means of Piezosurgery(R). Furthermore, through an examination of the available scientific literature, we wanted to establish whether the frequency of postoperative complications were consistent with those already reported. A retrospective study on 58 patients who underwent orthognathic surgery with a bilateral sagittal osteotomy (BSSO) of the mandibular bone branch, maxillary surgery with Le Fort I mono-segmented or multi-segmented approach, and genioplasty technique using Piezosurgery(R). The complications taken into consideration were disorders of the temporomandibular joint (TMJ), paraesthesia and hypoesthesia, asymmetries, nose enlargement, nasal septum deviation, nasal obstruction, dental discolorations, pulpal necrosis, occlusion and masticatory efficiency, gingival recession, periodontal problems, dysgeusia, nausea and vomiting, weeping alterations, hearing problems, delayed healing, superinfection, removal of synthesis means, reoperation, cicatricial outcome, and bilateral pneumothorax. It has been highlighted that a number and type of postoperative complications matched those reported by the most recent literature reviews. Temporomandibular disorders and paraesthesia were the most common ones. The only complication rate that differed from the literature was nerve damage, which was significantly lower. Post-surgical complications depend on the used surgical techniques, clinical work, and treatment methods. The use of piezoelectric devices in orthognathic surgery operations provides an innovative, safe, and effective technique compared to traditional methods

The boundary Riemann solver coming from the real vanishing viscosity approximation

We study a family of initial boundary value problems associated to mixed hyperbolic-parabolic systems: v^{\epsilon} _t + A (v^{\epsilon}, \epsilon v^{\epsilon}_x ) v^{\epsilon}_x = \epsilon B (v^{\epsilon} ) v^{\epsilon}_{xx} The conservative case is, in particular, included in the previous formulation. We suppose that the solutions $v^{\epsilon}$ to these problems converge to a unique limit. Also, it is assumed smallness of the total variation and other technical hypotheses and it is provided a complete characterization of the limit. The most interesting points are the following two. First, the boundary characteristic case is considered, i.e. one eigenvalue of $A$ can be $0$. Second, we take into account the possibility that $B$ is not invertible. To deal with this case, we take as hypotheses conditions that were introduced by Kawashima and Shizuta relying on physically meaningful examples. We also introduce a new condition of block linear degeneracy. We prove that, if it is not satisfied, then pathological behaviours may occur.Comment: 84 pages, 6 figures. Text changes in Sections 1 and 3.2.3. Added Section 3.1.2. Minor changes in other section

Partialization losses of ON/OFF operation of waterto- water refrigeration/heat-pump units

[EN] This paper presents the results of an experimental campaign for the characterization of the dynamic behavior of a water-to-water refrigeration/heat-pump unit under ON/OFF operation. The unit was previously tested at different water inlet temperatures under steady state conditions, and a very good agreement was found between the instantaneous dynamic performance of the heat pump and the corresponding quasi-steady state operation. In parallel, a series of tests were carried out to quantify the coefficient of performance (COP) degradation as a function of the load ratio, and a simple formula for the Part Load Factor is presented. Results lead to the conclusion that the only non-negligible factor in the COP degradation is the stand-by electrical consumption during the OFF period, especially at low load ratios. Finally, it is concluded that the minimization of the stand-by consumption is a key point for the future improvement of the seasonal performance of water-to-water systems.This research has been partially funded by the European FP7 framework project "Advanced ground source heat pump systems for heating and cooling in Mediterranean climate" (GROUND-MED) and the Spanish Ministry of Economy and Competitiveness (MINECO) through the project "Estudio de evaporadores y condensadores basados en tecnologia de minicanales para su aplicaciOn en equipos de aire acondicionado, refrigeraciOn y bomba de calor estacionarios" with reference DPI2011-26771-C02-01. The authors gratefully acknowledge their financial support.Corberán, JM.; D.Donadello; Martínez Galván, IO.; Montagud, C. (2013). Partialization losses of ON/OFF operation of waterto- water refrigeration/heat-pump units. International Journal of Refrigeration. 36(8):2251-2261. https://doi.org/10.1016/j.ijrefrig.2013.07.002S2251226136

Spontaneous creation of Kibble-Zurek solitons in a Bose-Einstein condensate

When a system crosses a second-order phase transition on a finite timescale, spontaneous symmetry breaking can cause the development of domains with independent order parameters, which then grow and approach each other creating boundary defects. This is known as Kibble-Zurek mechanism. Originally introduced in cosmology, it applies both to classical and quantum phase transitions, in a wide variety of physical systems. Here we report on the spontaneous creation of solitons in Bose-Einstein condensates via the Kibble-Zurek mechanism. We measure the power-law dependence of defects number with the quench time, and provide a check of the Kibble-Zurek scaling with the sonic horizon. These results provide a promising test bed for the determination of critical exponents in Bose-Einstein condensates.Comment: 7 pages, 4 figure

Fatal cytokine release syndrome by an aberrant FLIP/STAT3 axis

Inflammatory responses rapidly detect pathogen invasion and mount a regulated reaction. However, dysregulated anti-pathogen immune responses can provoke life-threatening inflammatory pathologies collectively known as cytokine release syndrome (CRS), exemplified by key clinical phenotypes unearthed during the SARS-CoV-2 pandemic. The underlying pathophysiology of CRS remains elusive. We found that FLIP, a protein that controls caspase-8 death pathways, was highly expressed in myeloid cells of COVID-19 lungs. FLIP controlled CRS by fueling a STAT3-dependent inflammatory program. Indeed, constitutive expression of a viral FLIP homolog in myeloid cells triggered a STAT3-linked, progressive, and fatal inflammatory syndrome in mice, characterized by elevated cytokine output, lymphopenia, lung injury, and multiple organ dysfunctions that mimicked human CRS. As STAT3-targeting approaches relieved inflammation, immune disorders, and organ failures in these mice, targeted intervention towards this pathway could suppress the lethal CRS inflammatory state

Atomic Clocks Technologies Supporting Twin-Field QKD in a Real World

We describe the exploitation of narrow linewidth lasers and coherent laser interferometry techniques originally developed in the atomic clocks community to improve the performances of twin-field quantum key distribution protocols in real-world, long-distance fiber networks