Position-dependent mass systems: Classical and quantum pictures

Extended abstract of "Algebraic approach to position-dependent mass systems in both classical and quantum pictures", a series of three lectures delivered by the author in the VIII School on Geometry and Physics, 24 June-8 June 2019, organized by the Department of Mathematical Physics of the University of Bialystok, in Bialowieza, Poland (http://wgmp.uwb.edu.pl/wgmp38/part_s.html)Comment: 12 pages, no figure

Open Data for Global Science

The global science system stands at a critical juncture. On the one hand, it is overwhelmed by a hidden avalanche of ephemeral bits that are central components of modern research and of the emerging ‘cyberinfrastructure’4 for e-Science.5 The rational management and exploitation of this cascade of digital assets offers boundless opportunities for research and applications. On the other hand, the ability to access and use this rising flood of data seems to lag behind, despite the rapidly growing capabilities of information and communication technologies (ICTs) to make much more effective use of those data. As long as the attention for data policies and data management by researchers, their organisations and their funders does not catch up with the rapidly changing research environment, the research policy and funding entities in many cases will perpetuate the systemic inefficiencies, and the resulting loss or underutilisation of valuable data resources derived from public investments. There is thus an urgent need for rationalised national strategies and more coherent international arrangements for sustainable access to public research data, both to data produced directly by government entities and to data generated in academic and not-for-profit institutions with public funding. In this chapter, we examine some of the implications of the ‘data driven’ research and possible ways to overcome existing barriers to accessibility of public research data. Our perspective is framed in the context of the predominantly publicly funded global science system. We begin by reviewing the growing role of digital data in research and outlining the roles of stakeholders in the research community in developing data access regimes. We then discuss the hidden costs of closed data systems, the benefits and limitations of openness as the default principle for data access, and the emerging open access models that are beginning to form digitally networked commons. We conclude by examining the rationale and requirements for developing overarching international principles from the top down, as well as flexible, common-use contractual templates from the bottom up, to establish data access regimes founded on a presumption of openness, with the goal of better capturing the benefits from the existing and future scientific data assets. The ‘Principles and Guidelines for Access to Research Data from Public Funding’ from the Organisation for Economic Cooperation and Development (OECD), reported on in another article by Pilat and Fukasaku,6 are the most important recent example of the high-level (inter)governmental approach. The common-use licenses promoted by the Science Commons are a leading example of flexible arrangements originating within the community. Finally, we should emphasise that we focus almost exclusively on the policy—the institutional, socioeconomic, and legal aspects of data access—rather than on the technical and management practicalities that are also important, but beyond the scope of this article

Varying constants, Gravitation and Cosmology

Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. It is thus of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We thus detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, Solar system observations, meteorites dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.Comment: 145 pages, 10 figures, Review for Living Reviews in Relativit

From Architectured Materials to Large-Scale Additive Manufacturing

The classical material-by-design approach has been extensively perfected by materials scientists, while engineers have been optimising structures geometrically for centuries. The purpose of architectured materials is to build bridges across themicroscale ofmaterials and themacroscale of engineering structures, to put some geometry in the microstructure. This is a paradigm shift. Materials cannot be considered monolithic anymore. Any set of materials functions, even antagonistic ones, can be envisaged in the future. In this paper, we intend to demonstrate the pertinence of computation for developing architectured materials, and the not-so-incidental outcome which led us to developing large-scale additive manufacturing for architectural applications

Diagnosis and prognosis of complex energy storage systems: tools development and feedback on four installed systems

International audienceElectrical Storage systems are used since many decades in stand-alone applications. Recently, their use in grid connected renewable energies installations increases not only the flexibility of these systems but also their complexity. The optimization of their operation in these systems is necessary for cost effectiveness and is a technical and scientific challenge. The research and development projects are increasing worldwide to tackle different aspects of these new solutions. This paper presents advanced analysis of some of these systems based on new approaches of data analytics. Four PV-Storage systems have been monitored for three years and an original diagnostic and prognostic tool is developed for the analysis of the performance and defaults of such systems.In addition, the generic approach presented in this paper allowed to have a feedback on the performance of grid connected PV-storage systems with two different storage technologies: Li-ion and NaNiCl2. The efficiency analysis includes the performance of batteries and power conversion systems. So, the objective here is to compare the usage and the performance of electrical storage systems along time within each power plant and also between the monitoring power plants using experts’ knowledge and data processing

Waterlow score as a surrogate marker for predicting adverse outcome in acute pancreatitis.

Introduction Introduced originally to stratify risk for developing decubitus ulcers, the Waterlow scoring system is recorded routinely for surgical admissions. It is a composite score, reflecting patients' general condition and co-morbidities. The aim of this study was to investigate whether the Waterlow score can be used as an independent surrogate marker to predict severity and adverse outcome in acute pancreatitis. Methods In this retrospective analysis, a consecutive cohort was studied of 250 patients presenting with acute pancreatitis, all of whom had their Waterlow score calculated on admission. Primary outcome measures were length of hospital stay and mortality. Secondary outcome measures included rate of intensive care unit (ICU) admission and development of complications such as peripancreatic free fluid, pancreatic necrosis and pseudocyst formation. Correlation of the Waterlow score with some known markers of disease severity and outcomes was also analysed. Results The Waterlow score correlated strongly with the most commonly used marker of disease severity, the Glasgow score (analysis of variance, p=0.0012). Inpatient mortality, rate of ICU admission and length of hospital stay increased with a higher Waterlow score (Mann-Whitney U test, p=0.0007, p=0.049 and p=0.0002 respectively). There was, however, no significant association between the Waterlow score and the incidence of three known complications of pancreatitis: presence of peripancreatic fluid, pancreatic pseudocyst formation and pancreatic necrosis. Receiver operating characteristic curve analysis demonstrated good predictive power of the Waterlow score for mortality (area under the curve [AUC]: 0.73), ICU admission (AUC: 0.65) and length of stay >7 days (AUC: 0.64). This is comparable with the predictive power of the Glasgow score and C-reactive protein. Conclusions The Waterlow score for patients admitted with acute pancreatitis could provide a useful tool in prospective assessment of disease severity, help clinicians with appropriate resource management and inform patients

Third and fifth harmonic responses in viscous liquids

International audienceWe review the works devoted to third and fifth harmonic susceptibilities in glasses, namely χ (3) 3 and χ (5) 5. We explain why these nonlinear responses are especially well adapted to test whether or not some amorphous correlations develop upon cooling. We show that the experimental frequency and temperature dependences of χ (3) 3 and of χ (5) 5 have anomalous features, since their behavior is qualitatively different to that of an ideal gas, which is the high-temperature limit of a fluid. Most of the works have interpreted this anomalous behavior as reflecting the growth, upon cooling, of amorphously ordered domains, as predicted by the general framework of Bouchaud and Biroli (BB). We explain why most—if not all—of the challenging interpretations can be recast in a way which is consistent with that of Bouchaud and Biroli. Finally, the comparison of the anomalous features of χ (5) 5 and of χ (3) 3 shows that the amorphously ordered domains are compact, i.e., the fractal dimension d f is close to the dimension d of space. This suggests that the glass transition of molecular liquids corresponds to a new universality class of critical phenomena