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See detailAbsence of strong skew scattering in crystals with multi-sheeted Fermi surfaces
Hönemann, Albert; Herschbach, Christian; Fedorov, Dmitry UL et al

in Journal of Physics: Condensed Matter (2019), 31

We consider an extrinsic contribution to the anomalous and spin Hall effect in dilute alloys based on Fe, Co, Ni, and Pt hosts with different substitutional impurities. It is shown that a strong skew ... [more ▼]

We consider an extrinsic contribution to the anomalous and spin Hall effect in dilute alloys based on Fe, Co, Ni, and Pt hosts with different substitutional impurities. It is shown that a strong skew-scattering mechanism is absent in such crystals with multi-sheeted Fermi surfaces. Based on this finding, we conclude on the mutual exclusion of strong intrinsic and skew-scattering contributions to the considered transport phenomena. It also allows us to draw general conclusions in which materials with a giant anomalous Hall effect caused by the skew scattering can be achieved. [less ▲]

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See detailRole of tetrahedrally coordinated dopants in palladium hydrides on their superconductivity and inverse isotope effect
Ostanin, Sergey; Borisov, Vladislav; Fedorov, Dmitry UL et al

in Journal of Physics: Condensed Matter (2019), 31

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See detailSpin caloric transport from density-functional theory
Popescu, Voicu; Kratzer, Peter; Entel, Peter et al

in Journal of Physics: D Applied Physics (2019), 52

Spin caloric transport refers to the coupling of heat with spin transport. Its applications primarily concern the generation of spin currents and control of magnetisation by temperature gradients for ... [more ▼]

Spin caloric transport refers to the coupling of heat with spin transport. Its applications primarily concern the generation of spin currents and control of magnetisation by temperature gradients for information technology, known by the synonym spin caloritronics. Within the framework of ab initio theory, new tools are being developed to provide an additional understanding of these phenomena in realistic materials, accounting for the complexity of the electronic structure without adjustable parameters. Here, we review this progress, summarising the principles of the density-functional-based approaches in the field and presenting a number of application highlights. Our discussion includes the three most frequently employed approaches to the problem, namely the Kubo, Boltzmann, and Landauer–Büttiker methods. These are showcased in specific examples that span, on the one hand, a wide range of materials, such as bulk metallic alloys, nano-structured metallic and tunnel junctions, or magnetic overlayers on heavy metals, and, on the other hand, a wide range of effects, such as the spin-Seebeck, magneto-Seebeck, and spin-Nernst effects, spin disorder, and the thermal spin-transfer and thermal spin–orbit torques. [less ▲]

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See detailMicrostructural-defect-induced Dzyaloshinskii-Moriya interaction
Michels, Andreas UL; Mettus, Denis; Titov, Ivan UL et al

in Physical Review. B, Condensed Matter (2019), 99

See detailA Specialized Method to Resolve Fine 3D Features of Astrocytes in Nonhuman Primate (Marmoset, Callithrix jacchus) and Human Fixed Brain Samples.
Quesseveur, Gael; Fouquier d'Hérouël, Aymeric UL; Murai, Keith K. et al

in Methods in molecular biology (Clifton, N.J.) (2019), 1938

Astrocytes are among the most numerous cells in the brain and fulfill diverse functions in homeostasis and regulation of neuronal activity. Astrocytes also dramatically change their properties in response ... [more ▼]

Astrocytes are among the most numerous cells in the brain and fulfill diverse functions in homeostasis and regulation of neuronal activity. Astrocytes also dramatically change their properties in response to brain injury or disease, a process called reactive gliosis. Precisely how astrocytes contribute to healthy brain function and play differential roles in brain pathology and regeneration remain important areas of investigation. To better understand the properties of astrocytes, more sophisticated approaches for probing their rich and complex anatomical and molecular features are needed to fully determine their contribution to brain physiology. Here we present an efficient and straightforward immunolabeling protocol to obtain high-resolution fluorescence-based images from fixed nonhuman primate (common marmoset Callithrix jacchus) and human brain samples. Importantly, the protocol is useful for obtaining images from samples that have been stored in fixative solutions (such as formalin) for years. This approach is especially useful for three-dimensional, multichannel confocal microscopy and can be optimized for super-resolution techniques such as stimulated emission depletion (STED) microscopy. We also present a strategy for using specific combinations of markers to define the phenotypic variations and cellular/subcellular properties of astrocytes to better predict the function of these cells on their surrounding brain microenvironment. [less ▲]

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See detailStability of functionalized platform molecules on Au(111)
Jasper-Tönnies, Torben; Poltavskyi, Igor UL; Ulrich, Sandra et al

in Journal of Chemical Physics (2018), 149

Trioxatriangulenium (TOTA) platform molecules were functionalized with methyl, ethyl, ethynyl, propynyl, and hydrogen and sublimated onto Au(111) surfaces. Low-temperature scanning tunneling microscopy ... [more ▼]

Trioxatriangulenium (TOTA) platform molecules were functionalized with methyl, ethyl, ethynyl, propynyl, and hydrogen and sublimated onto Au(111) surfaces. Low-temperature scanning tunneling microscopy data reveal that >99% of ethyl-TOTA and methyl-TOTA remain intact, whereas 60% of H-TOTA and >99% of propynyl-TOTA and ethynyl-TOTA decompose. The observed tendency toward fragmentation on Au(111) is opposite to the sequence of gas-phase stabilities of the molecules. Although Au(111) is the noblest of all metal surfaces, the binding energies of the decomposition products to Au(111) destabilize the functionalized platforms by 2 to 3.9 eV (190–370 kJ/mol) and even render some of them unstable as revealed by density functional theory calculations. Van der Waals forces are important, as they drive the adsorption of the platform molecules. [less ▲]

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See detailLubrication mechanism design for aircraft landing gear bearings
Heirendt, Laurent UL; Hugh, Hugh H.T.; Wang, Phillip

Patent (2018)

A shock absorber with lubricated bearings for an aircraft landing gear includes a piston that is received in a cylinder, and an upper bearing fixed to the piston that slidably engages an inner surface of ... [more ▼]

A shock absorber with lubricated bearings for an aircraft landing gear includes a piston that is received in a cylinder, and an upper bearing fixed to the piston that slidably engages an inner surface of the cylinder. A lower bearing extends inwardly from a lower portion of the cylinder and engages an outer surface of the piston. The lower bearing has a center axis and defines an annular bearing surface configured to slidably engage the piston outer surface. The annular bearing surface has a first portion that extends circumferentially more than one hundred eighty degrees about the center axis at a constant radius, defining a circular annular segment. A second portion closes the circular annular segment and defines a shallow channel or pocket in the annular bearing surface. In some embodiments the lower bearing further comprises oppositely disposed frustoconical thrust portions. [less ▲]

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See detailSimulation study of the electrical tunneling network conductivity of suspensions of hard spherocylinders
Atashpendar, Arshia; Arora, Sarthak; Rahm, Alexander UL et al

in Physical Review. E. (2018), 98

Using Monte Carlo simulations, we investigate the electrical conductivity of networks of hard rods with aspect ratios 10 and 20 as a function of the volume fraction for two tunneling conductance models ... [more ▼]

Using Monte Carlo simulations, we investigate the electrical conductivity of networks of hard rods with aspect ratios 10 and 20 as a function of the volume fraction for two tunneling conductance models. For a simple, orientationally independent tunneling model, we observe nonmonotonic behavior of the bulk conductivity as a function of volume fraction at the isotropic-nematic transition. However, this effect is lost if one allows for anisotropic tunneling. The relative conductivity enhancement increases exponentially with volume fraction in the nematic phase. Moreover, we observe that the orientational ordering of the rods in the nematic phase induces an anisotropy in the conductivity, i.e., enhanced values in the direction of the nematic director field. We also compute the mesh number of the Kirchhoff network, which turns out to be a simple alternative to the computationally expensive conductivity of large systems in order to get a qualitative estimate. [less ▲]

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See detailTemporal enhancer profiling of parallel lineages identifies AHR and GLIS1 as regulators of mesenchymal multipotency
Gerard, Déborah UL; Schmidt, Florian; Ginolhac, Aurélien UL et al

in Nucleic Acids Research (2018)

Temporal data on gene expression and context-specific open chromatin states can improve identification of key transcription factors (TFs) and the gene regulatory networks (GRNs) controlling cellular ... [more ▼]

Temporal data on gene expression and context-specific open chromatin states can improve identification of key transcription factors (TFs) and the gene regulatory networks (GRNs) controlling cellular differentiation. However, their integration remains challenging. Here, we delineate a general approach for data-driven and unbiased identification of key TFs and dynamic GRNs, called EPIC-DREM. We generated time-series transcriptomic and epigenomic profiles during differentiation of mouse multipotent bone marrow stromal cell line (ST2) toward adipocytes and osteoblasts. Using our novel approach we constructed time-resolved GRNs for both lineages and identifed the shared TFs involved in both differentiation processes. To take an alternative approach to prioritize the identified shared regulators, we mapped dynamic super-enhancers in both lineages and associated them to target genes with correlated expression profiles. The combination of the two approaches identified aryl hydrocarbon receptor (AHR) and Glis family zinc finger 1 (GLIS1) as mesenchymal key TFs controlled by dynamic cell type-specific super-enhancers that become repressed in both lineages. AHR and GLIS1 control differentiation-induced genes and their overexpression can inhibit the lineage commitment of the multipotent bone marrow-derived ST2 cells. [less ▲]

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See detailNonlinear Approximations in Cryptanalysis Revisited
Beierle, Christof UL; Canteaut, Anne; Leander, Gregor

in IACR Transactions on Symmetric Cryptology (2018), 2018(4), 80-101

This work studies deterministic and non-deterministic nonlinear approximations for cryptanalysis of block ciphers and cryptographic permutations and embeds it into the well-understood framework of linear ... [more ▼]

This work studies deterministic and non-deterministic nonlinear approximations for cryptanalysis of block ciphers and cryptographic permutations and embeds it into the well-understood framework of linear cryptanalysis. For a deterministic (i.e., with correlation ±1) nonlinear approximation we show that in many cases, such a nonlinear approximation implies the existence of a highly-biased linear approximation. For non-deterministic nonlinear approximations, by transforming the cipher under consideration by conjugating each keyed instance with a fixed permutation, we are able to transfer many methods from linear cryptanalysis to the nonlinear case. Using this framework we in particular show that there exist ciphers for which some transformed versions are significantly weaker with regard to linear cryptanalysis than their original counterparts. [less ▲]

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See detailSymbol-Level Precoding for Low Complexity Transmitter Architectures in Large-Scale Antenna Array Systems
Domouchtsidis, Stavros; Tsinos, Christos UL; Chatzinotas, Symeon UL et al

in IEEE Transactions on Wireless Communications ( Early Access ) (2018)

In this paper we consider three transmitter designs for symbol-level-precoding (SLP), a technique that mitigates multiuser interference (MUI) in multiuser systems by designing the transmitted signals ... [more ▼]

In this paper we consider three transmitter designs for symbol-level-precoding (SLP), a technique that mitigates multiuser interference (MUI) in multiuser systems by designing the transmitted signals using the Channel State Information and the information-bearing symbols. The considered systems tackle the high hardware complexity and power consumption of existing SLP techniques by reducing or completely eliminating fully digital Radio Frequency (RF) chains. The first proposed architecture referred as, Antenna Selection SLP, minimizes the MUI by activating a subset of the available antennas and thus, reducing the number of required RF chains to the number of active antennas. In the other two architectures, which we refer to as RF domain SLP, the processing happens entirely in the RF domain, thus eliminating the need for multiple fully digital RF chains altogether. Instead, analog phase shifters directly modulate the signals on the transmit antennas. The precoding design for all the considered cases is formulated as a constrained least squares problem and efficient algorithmic solutions are developed via the Coordinate Descent method. Simulations provide insights on the power efficiency of the proposed schemes and the improvements over the fully digital counterparts. [less ▲]

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See detailData Exchange Interoperability in IoT Ecosystem for Smart Parking and EV Charging
Karpenko, Anastasiia; Kinnunen, Tuomas; Madhikermi, Manik et al

in Sensors (2018)

Many domains are trying to integrate with the Internet of Things (IoT) ecosystem, such as public administrations starting smart city initiatives all over the world. Cities are becoming smart in many ways ... [more ▼]

Many domains are trying to integrate with the Internet of Things (IoT) ecosystem, such as public administrations starting smart city initiatives all over the world. Cities are becoming smart in many ways: smart mobility, smart buildings, smart environment and so on. However, the problem of non-interoperability in the IoT hinders the seamless communication between all kinds of IoT devices. Different domain specific IoT applications use different interoperability standards. These standards are usually not interoperable with each other. IoT applications and ecosystems therefore tend to use a vertical communication model that does not allow data sharing horizontally across different IoT ecosystems. In 2014, The Open Group published two domain-independent IoT messaging standards, O-MI and O-DF, aiming to solve the interoperability problem. In this article we describe the practical use of O-MI/O-DF standards for reaching interoperability in a mobile application for the smart city context, in particular for the Smart Mobility domain, electric vehicle (EV) charging case study. The proof-of-concept of the smart EV charging ecosystem with mobile application user interface was developed as a part of an EU (Horizon 2020) Project bIoTope. [less ▲]

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See detailCan we automate away the main challenges of end-to-end testing?
Rwemalika, Renaud UL; Kintis, Marinos UL; Papadakis, Mike UL et al

Scientific Conference (2018, December 11)

Agile methodologies enable companies to drastically increase software release pace and reduce time-to-market. In a rapidly changing environment, testing becomes a cornerstone of the software development ... [more ▼]

Agile methodologies enable companies to drastically increase software release pace and reduce time-to-market. In a rapidly changing environment, testing becomes a cornerstone of the software development process, guarding the system code base from the insertion of faults. To cater for this, many companies are migrating manual end-to-end tests to automated ones. This migration introduces several challenges to the practitioners. These challenges relate to difficulties in the creation of the automated tests, their maintenance and the evolution of the test code base. In this position paper, we discuss our preliminary results on such challenges and present two potential solutions to these problems, focusing on keyword-driven end-to-end tests. Our solutions leverage existing software artifacts, namely the test suite and an automatically-created model of the system under test, to support the evolution of keyword-driven test suites. [less ▲]

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See detailFailure to eliminate a phosphorylated glucose analog leads to neutropenia in patients with G6PT and G6PC3 deficiency
Veiga-da-Cunha, Maria; Chevalier, Nathalie; Stephenne, Xavier et al

in Proceedings of the National Academy of Sciences of the United States of America (2018)

Neutropenia presents an important clinical problem in patients with G6PC3 or G6PT deficiency, yet why neutropenia occurs is unclear. We discovered that G6PC3 and G6PT collaborate to dephosphorylate a ... [more ▼]

Neutropenia presents an important clinical problem in patients with G6PC3 or G6PT deficiency, yet why neutropenia occurs is unclear. We discovered that G6PC3 and G6PT collaborate to dephosphorylate a noncanonical metabolite (1,5anhydroglucitol-6-phosphate; 1,5AG6P) which is produced when glucose-phosphorylating enzymes erroneously act on 1,5-anhydroglucitol, a food-derived polyol present in blood. In patients or mice with G6PC3 or G6PT deficiency, 1,5AG6P accumulates and inhibits the first step of glycolysis. This is particularly detrimental in neutrophils, since their energy metabolism depends almost entirely on glycolysis. Consistent with our findings, we observed that treatment with a 1,5anhydroglucitol-lowering drug treats neutropenia in G6PC3deficient mice. Our findings highlight that the elimination of noncanonical side products by metabolite-repair enzymes makes an important contribution to mammalian physiology. [less ▲]

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See detailA Discrete-Continuous Method for Predicting Thermochemical Phenomena in a Cement Kiln and Supporting Indirect Monitoring
Copertaro, Edoardo UL; Estupinan Donoso, Alvaro Antonio UL; Peters, Bernhard UL

in Engineering Journal (2018), 22(6), 165-183

Thermochemical phenomena involved in cement kilns are still not well understood because of their complexity, besides technical difficulties in achieving direct measurements of critical process variables ... [more ▼]

Thermochemical phenomena involved in cement kilns are still not well understood because of their complexity, besides technical difficulties in achieving direct measurements of critical process variables. This article addresses the problem of their comprehensive numerical prediction. The presented numerical model exploits Computational Fluid Dynamics and Finite Difference Method approaches for solving the gas domain and the rotating wall, respectively. The description of the thermochemical conversion and movement of the powder particles is addressed with a Lagrangian approach. Coupling between gas, particles and the rotating wall includes momentum, heat and mass transfer. Three-dimensional numerical predictions for a full-size cement kiln are presented and they show agreement with experimental data and benchmark literature. The quality and detail of the results are believed to provide a new insight into the functioning of a cement kiln. Attention is paid to the computational burden of the model and a methodology is presented for reducing the time-to-solution and paving the way for its exploitation in quasireal-time, indirect monitoring. [less ▲]

See detailSystems ecology of microbiomes
Wilmes, Paul UL

Scientific Conference (2018, December)

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See detailMicrobiome: the environment within
Wilmes, Paul UL

Scientific Conference (2018, December)

Detailed reference viewed: 18 (3 UL)
See detailHabitudes de lecture et compétences de lecture bilingue
Reichert, Monique UL; Krämer, Charlotte UL; Wollschläger, Rachel UL et al

in LUCET; SCRIPT (Eds.) Rapport national sur l'éducation au Luxembourg (2018)

La problématique soulevée dans cet article concerne les liens entre d’une part, la fréquence de lecture chez les adolescents en fonction des types de textes lus, et de la langue dans laquelle ils lisent ... [more ▼]

La problématique soulevée dans cet article concerne les liens entre d’une part, la fréquence de lecture chez les adolescents en fonction des types de textes lus, et de la langue dans laquelle ils lisent et, dautre part, leur niveau de compétence de lecture en allemand et en français. En outre, il s’agit d’étudier ces liens en fonction des contextes socio-économique et migratoire, de la langue maternelle, et du sexe des adolescents. À cet effet, les données recueillies dans le cadre des Épreuves Standardisées (ÉpStan) de novembre 2016 permettent d’analyser les compétences de lecture en allemand et en français ainsi que les habitudes de lecture extrascolaire de 5177 élèves du grade 9, fréquentant l’Enseignement Secondaire (ES), l’Enseignement Secondaire Technique (EST) ou la branche Préparatoire de l’Enseignement Secondaire Technique (EST-PRE). Les analyses montrent clairement que, indépendamment du sexe, du type d’enseignement et des caractéristiques socioculturelles des adolescents, principalement la tendance à lire des textes narratifs est positivement corrélée aux compétences en lecture. [less ▲]

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