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We perform systematic investigations of transport through graphene on hexagonal boron nitride (hBN) substrates, together with confocal Raman measurements and a targeted theoretical analysis, to identify the dominant source of disorder in this system. Low-temperature transport measurements on many devices reveal a clear correlation between the carrier mobility μ and the width n* of the resistance peak around charge neutrality, demonstrating that charge scattering and density inhomogeneities originate from the same microscopic mechanism. The study of weak localization unambiguously shows that this mechanism is associated with a long-ranged disorder potential and provides clear indications that random pseudomagnetic fields due to strain are the dominant scattering source. Spatially resolved Raman spectroscopy measurements confirm the role of local strain fluctuations, since the linewidth of the Raman 2D peak—containing information of local strain fluctuations present in graphene—correlates with the value of maximum observed mobility. The importance of strain is corroborated by a theoretical analysis of the relation between μ and n* that shows how local strain fluctuations reproduce the experimental data at a quantitative level, with n* being determined by the scalar deformation potential and μ by the random pseudomagnetic field (consistently with the conclusion drawn from the analysis of weak localization). Throughout our study, we compare the behavior of devices on hBN substrates to that of devices on SiO2 and SrTiO3 , and find that all conclusions drawn for the case of hBN are compatible with the observations made on these other materials. These observations suggest that random strain fluctuations are the dominant source of disorder for high-quality graphene on many different substrates, and not only on hexagonal boron nitride.

The ATLAS experiment is preparing a major change in the conditions data infrastructure in view of LHC Run 4. In this paper we describe the ongoing changes in the database architecture which have been implemented for Run 3, and describe the motivations and the on-going developments for the deployment of a new system (called CREST for Conditions Representational State Transfer, as a reference to REST architectures). The main goal is to set up a parallel infrastructure for full scale testing before the end of Run 3.

Malnutrition among children population of less developed countries is a major health problem. Inadequate food intake and infectious diseases are combined to increase further the prevalence. Malnourishment brings to muscle cells loss with development of cardiac complications, like arrhythmias, cardiomyopathy and sudden death. In developed countries, malnutrition has generally a different etiology, like chronic diseases. The aim of our study was to investigate the correlation between malnutrition and left ventricular mass in an African children population. 313 children were studied, in the region of Antsiranana, Madagascar, with age ranging from 4 to 16 years old (mean 7,8 ± 3 years). A clinical and echocardiographic evaluation was performed with annotation of anthropometric and left ventricle parameters. Malnutrition was defined as a body mass index (BMI) value age- and sex-specific of 16, 17 and 18,5 at the age of 18, or under the 15th percentile. Left ventricle mass was indexed by height2.7 (LVMI). We identified a very high prevalence of children malnutrition: 124 children, according to BMI values, and 100 children under the 15th percentile. LVMI values have shown to be increased in proportion to BMI percentiles ranging from 29,8 ± 10,8 g/m2.7 in the malnutrition group to 45 ± 15,1 g/m2.7 in >95th percentile group. LVMI values in children < 15th BMI percentile were significantly lower compared to normal nutritional status (29,8 ± 10,8 g/m2,7 vs. 32,9 ± 12,1 g/m2,7, p = 0.02). Also with BMI values evaluation, malnourished children showed statistically lower values of LVMI (29,3 ± 10,1 g/m2,7 vs. 33,6 ± 12,5 g/m2,7, p = 0.001). In African children population, the malnourishment status is correlated with cardiac muscle mass decrease, which appears to be reduced in proportion to the decrease in body size.

When thinned down to the atomic scale, many layered van der Waals materials exhibit an interesting evolution of their electronic properties, whose main aspects can be accounted for by changes in the single-particle bandstructure. Phenomena driven by interactions are also observed, but identifying experimentally systematic trends in their thickness dependence is challenging. Here, we explore the evolution of gate-induced superconductivity in exfoliated MoS 2 multilayers ranging from bulk-like to individual monolayers. We observe a clear transition for all thicknesses down to the ultimate atomic limit, providing the first demonstration of gate-induced superconductivity in atomically thin exfoliated crystals. Additionally, we characterize the superconducting state by measuring the critical temperature T C and magnetic field B C in a large number of multilayer devices while decreasing their thickness. We find that the superconducting properties exhibit a pronounced reduction in T C and B C when going from bilayers to monolayers, for which we discuss possible microscopic mechanisms. Superconductivity can be induced in a two-dimensional material down to the single-layer limit by ionic liquid gating.

The ability to gate-induce superconductivity by electrostatic charge accumulation is a recent breakthrough in physics and nanoelectronics. With the exception of LaAlO3/SrTiO3 interfaces, experiments on gate-induced superconductors have been largely confined to resistance measurements, which provide very limited information about the superconducting state. Here, we explore gate-induced superconductivity in MoS2 by performing tunnelling spectroscopy to determine the energy-dependent density of states (DOS) for different levels of electron density n. In the superconducting state, the DOS is strongly suppressed at energy smaller than the gap Δ, which is maximum (Δ ~2 meV) for n of ~1 × 1014 cm−2 and decreases monotonously for larger n. A perpendicular magnetic field B generates states at E < Δ that fill the gap, but a 20% DOS suppression of superconducting origin unexpectedly persists much above the transport critical field. Conversely, an in-plane field up to 10 T leaves the DOS entirely unchanged. Our measurements exclude that the superconducting state in MoS2 is fully gapped and reveal the presence of a DOS that vanishes linearly with energy, the explanation of which requires going beyond a conventional, purely phonon-driven Bardeen–Cooper–Schrieffer mechanism.

The increase in the scale of LHC computing during Run 3 and Run 4 (HL-LHC) will certainly require radical changes to the computing models and the data processing of the LHC experiments. The working group established by WLCG and the HEP Software Foundation to investigate all aspects of the cost of computing and how to optimise them has continued producing results and improving our understanding of this process. In particular, experiments have developed more sophisticated ways to calculate their resource needs, we have a much more detailed process to calculate infrastructure costs. This includes studies on the impact of HPC and GPU based resources on meeting the computing demands. We have also developed and perfected tools to quantitatively study the performance of experiments workloads and we are actively collaborating with other activities related to data access, benchmarking and technology cost evolution. In this contribution we expose our recent developments and results and outline the directions of future work.

The increase in the scale of LHC computing expected for Run 3 and even more so for Run 4 (HL-LHC) over the next ten years will certainly require radical changes to the computing models and the data processing of the LHC experiments. Translating the requirements of the physics programmes into computing resource needs is a complicated process and subject to significant uncertainties. For this reason, WLCG has established a working group to develop methodologies and tools intended tocharacterise the LHC workloads, better understand their interaction with the computing infrastructure, calculate their cost in terms of resources and expenditure and assist experiments, sites and the WLCG project in the evaluation of their future choices. This working group started in November 2017 and has about 30 active participants representing experiments and sites. In this contribution we expose the activities, the results achieved and the future directions.

Left ventricular hypertrophy (LVH) is a marker of pediatric hypertension and predicts development of cardiovascular events. Electrocardiography (ECG) screening is used in pediatrics to detect LVH thanks to major accessibility, reproducibility and easy to use compared to transthoracic echocardiography (TTE), that remains the standard technique. Several diseases were previously investigated, but no data exists regarding our study population. The aim of our study was to evaluate the relationship between electrocardiographic and echocardiographic criteria of LVH in normotensive African children. We studied 313 children (mean age 7,8 ± 3 yo), in north-Madagascar. They underwent ECG and TTE. Sokolow-Lyon index was calculated to identify ECG-LVH (>35 mm). Left ventricle mass (LVM) with TTE was calculated and indexed by height(2.7) (LVMI(2.7)) and weight (LVMI(w)). We report the prevalence of TTE-LVH using three methods: (1) calculating percentiles age- and sex- specific with values >95th percentile identifying LVH; (2) LVMI(2.7) >51 g/m(2.7); (3) LVMI(w) >3.4 g/weight. 40 (13%) children showed LVMI values >95th percentile, 24 children (8%) an LVMI(2.7) >51 g/m(2.7) while 19 children (6%) an LVMI(w) >3.4 g/kg. LVH-ECG by Sokolow-Lyon index was present in five, three and three children respectively, with poor values of sensitivity (ranging from 13 to 16%), positive predictive value (from 11 to 18%) and high values of specificity (up to 92%). The effects of anthropometrics parameters on Sokolow-Lyon were analyzed and showed poor correlation. ECG is a poor screening test for detecting LVH in children. In clinical practice, TTE remains the only tool to be used to exclude LVH.

When thinned down to the atomic scale, many layered van der Waals materials exhibit an interesting evolution of their electronic properties, whose main aspects can be accounted for by changes in the single-particle bandstructure. Phenomena driven by interactions are also observed, but identifying experimentally systematic trends in their thickness dependence is challenging. Here, we explore the evolution of gate-induced superconductivity in exfoliated MoS sub(2) multilayers ranging from bulk-like to individual monolayers. We observe a clear transition for all thicknesses down to the ultimate atomic limit, providing the first demonstration of gate-induced superconductivity in atomically thin exfoliated crystals. Additionally, we characterize the superconducting state by measuring the critical temperature T sub(C) and magnetic field B sub(C) in a large number of multilayer devices while decreasing their thickness. We find that the superconducting properties exhibit a pronounced reduction in T sub(C) and B sub(C) when going from bilayers to monolayers, for which we discuss possible microscopic mechanisms.

In the version of this Article originally published, an error during typesetting led to the curve in Fig. 2a being shifted to the right, and the curves in the inset of Fig. 2a being displaced. The figure has now been corrected in all versions of the Article; the original and corrected Fig. 2a are shown below.