Low-energy electrodynamics of superconducting diamond

Heavily-boron-doped diamond films become superconducting with critical temperatures $T_c$ well above 4 K. Here we first measure the reflectivity of such a film down to 5 cm$^{-1}$, by also using Coherent Synchrotron Radiation. We thus determine the optical gap, the field penetration depth, the range of action of the Ferrell-Glover-Tinkham sum rule, and the electron-phonon spectral function. We conclude that diamond behaves as a dirty BCS superconductor.Comment: 4 pages including 3 figure

Ground truth deficiencies in software engineering: when codifying the past can be counterproductive

Many software engineering tools build and evaluate their models based on historical data to support development and process decisions. These models help us answer numerous interesting questions, but have their own caveats. In a real-life setting, the objective function of human decision-makers for a given task might be influenced by a whole host of factors that stem from their cognitive biases, subverting the ideal objective function required for an optimally functioning system. Relying on this data as ground truth may give rise to systems that end up automating software engineering decisions by mimicking past sub-optimal behaviour. We illustrate this phenomenon and suggest mitigation strategies to raise awareness

Pressure dependence of the charge-density-wave gap in rare-earth tri-tellurides

We investigate the pressure dependence of the optical properties of CeTe$_3$, which exhibits an incommensurate charge-density-wave (CDW) state already at 300 K. Our data are collected in the mid-infrared spectral range at room temperature and at pressures between 0 and 9 GPa. The energy for the single particle excitation across the CDW gap decreases upon increasing the applied pressure, similarly to the chemical pressure by rare-earth substitution. The broadening of the bands upon lattice compression removes the perfect nesting condition of the Fermi surface and therefore diminishes the impact of the CDW transition on the electronic properties of $R$Te$_3$.Comment: 5 pages, 4 figure

Analysis of Circular Economy Research and Innovation (R&I) intensity for critical products in the supply chains of strategic technologies.

To develop renewable energy, digital, space and defence technologies, the European Union (EU) needs access to critical raw materials of which a large share is currently imported from third countries. To mitigate the risk of supply disruptions, the Critical Raw Materials Act proposes to diversify sources of imports, while increasing domestic extraction, processing, and recycling. The circular economy is therefore positioned as a key element of the EU strategy to deploy strategic technologies for navigating the sustainability transition in a complex geopolitical landscape. In line with this position, the present study analyses the intensity of circular economy research and innovation (R&I) in the supply chains of strategic technologies. The focus is placed on four critical products containing raw materials having high supply risks: lithium-ion battery cells; neodymium-iron-boron permanent magnets; photovoltaic cells; hydrogen electrolysers and fuel-cells. The R&I analysis is based on the identification of scientific articles, patents, and innovation projects on the subject, with a global scope, in the period between 2014 and 2022. The analysis is enriched by connecting to parallel work on the subject, conducted by Joint Research Centre (JRC) as well as academic institutions, industry, and policy stakeholders. This is functional to provide insight into: where circularity efforts R&I have been placed in terms of different products and supply chains; which countries are undertaking these efforts; how the EU is positioned and how much funding was deployed so far; what are the current gaps and trends going forward. Main insights include the following: 1) circularity R&I for critical products is not balanced, with a prominent focus placed on Li-ion cells on a global level 2) the EU has followed this trend in terms of number of innovation projects and public spending; 3) Next to EU efforts, China and the USA focus intensely on circular economy R&I as well. This study contributes with evidence to advance scientific research and policymaking on the role of a circular economy to achieve open strategic autonomy and climate neutrality in the EU

A Microscopic View on the Mott transition in Chromium-doped V2O3

V2O3 is the prototype system for the Mott transition, one of the most fundamental phenomena of electronic correlation. Temperature, doping or pressure induce a metal to insulator transition (MIT) between a paramagnetic metal (PM) and a paramagnetic insulator (PI). This or related MITs have a high technological potential, among others for intelligent windows and field effect transistors. However the spatial scale on which such transitions develop is not known in spite of their importance for research and applications. Here we unveil for the first time the MIT in Cr-doped V2O3 with submicron lateral resolution: with decreasing temperature, microscopic domains become metallic and coexist with an insulating background. This explains why the associated PM phase is actually a poor metal. The phase separation can be associated with a thermodynamic instability near the transition. This instability is reduced by pressure which drives a genuine Mott transition to an eventually homogeneous metallic state.Comment: Paper plus supplementary materia

First-in-human pharmacokinetics of tamoxifen and its metabolites in the milk of a lactating mother. A case study

Background Breast cancer represents the most frequent neoplasm diagnosed in women of childbearing age. When the tumour is oestrogen receptor-positive, tamoxifen is among the recommended endocrine treatments. Lactating women are advised not to breastfeed while receiving tamoxifen. However, information about tamoxifen transfer into breast milk is lacking. Methods We measured the concentration of tamoxifen and its metabolites by liquid chromatography-tandem mass spectrometry in the milk of a nursing mother that was treated for pregnancy-associated breast cancer diagnosed a few months after delivery. She was advised not to breastfeed her child and she collected milk samples for 23 days while the baby was fed with formula. Results Tamoxifen concentrations in milk increased reaching a maximum of 214 nM. The two active metabolitesZ-4-hydroxy-tamoxifen and Z-endoxifen, could not be quantified in milk the first days after tamoxifen intake, but increased over time and reached clinically significant levels after day 18. Conclusion This study demonstrates for the first time in human that tamoxifen and its metabolites transfer into milk. Since tamoxifen has a complete oral bioavailability, a long half-life (>7 days) and may interfere with the normal development of the infant, mothers should not breastfeed during tamoxifen treatment

Exploring drought‐to‐flood interactions and dynamics: A global case review

This study synthesizes the current understanding of the hydrological, impact, and adaptation processes underlying drought‐to‐flood events (i.e., consecutive drought and flood events), and how they interact. Based on an analysis of literature and a global assessment of historic cases, we show how drought can affect flood risk and assess under which circumstances drought‐to‐flood interactions can lead to increased or decreased risk. We make a distinction between hydrological, socio‐economic and adaptation processes. Hydrological processes include storage and runoff processes, which both seem to mostly play a role when the drought is a multiyear event and when the flood occurs during the drought. However, which process is dominant when and where, and how this is influenced by human intervention needs further research. Processes related to socio‐economic impacts have been studied less than hydrological processes, but in general, changes in vulnerability seem to play an important role in increasing or decreasing drought‐to‐flood impacts. Additionally, there is evidence of increased water quality problems due to drought‐to‐flood events, when compared to drought or flood events by themselves. Adaptation affects both hydrological (e.g., through groundwater extraction) or socio‐economic (e.g., influencing vulnerability) processes. There are many examples of adaptation, but there is limited evidence of when and where certain processes occur and why. Overall, research on drought‐to‐flood events is scarce. To increase our understanding of drought‐to‐flood events we need more comprehensive studies on the underlying hydrological, socio‐economic, and adaptation processes and their interactions, as well as the circumstances that lead to the dominance of certain processes. This article is categorized under: Science of Water > Hydrological Processes Science of Water > Water Extreme

All dried up: the materiality of drought in Ladismith, South Africa

This paper conceptualizes droughts as socioecological phenomena coproduced by the recursive engagement of human and non-human transformations. Through an interdisciplinary approach that integrates political ecology, material geographies and hydroclimatology, this work simultaneously apprehends the role of politics and power in reshaping drought, along with the agency of biophysical processes —soil, vegetation, hydrology and microclimate— that co-produce droughts and their spatiotemporal patterning. The drought-stricken Ladismith in Western Cape, South Africa, is the instrumental case study and point of departure of our empirical analysis. To advance a materiality of drought that seriously accounts for the coevolution of biophysical and political transformations, we alter the spatiotemporal and empirical foci of drought analyses thereby retracing Ladismith’s socioecological history since colonial times. In turn, such extended framework exposes the agency of soil, vegetation, hydrology and microclimate and their metabolic exchanges with processes of colonization, apartheid, capitalist and neoliberal transformations of South African economy. We argue that the narrow pursuit of profits and capital accumulation of the few has produced a fundamental disruption between nature and society which contributed to transform Ladismith’s drought into a socioecological crisis. Whilst advancing debates on materiality, we note two fundamental contributions to the study of drought. First, our approach makes hydrological accounts of droughts less politically naive and socially blind. Second, it develops a political ecology of droughts and socioecological crises more attuned to the materiality of drought. We contend that apprehending the materiality of drought and the active role of its non-human processes can further understandings of the workings of power and the production of socioecological injustices

Establishment and Validation of Computational Model for MT1-MMP Dependent ECM Degradation and Intervention Strategies

MT1-MMP is a potent invasion-promoting membrane protease employed by aggressive cancer cells. MT1-MMP localizes preferentially at membrane protrusions called invadopodia where it plays a central role in degradation of the surrounding extracellular matrix (ECM). Previous reports suggested a role for a continuous supply of MT1-MMP in ECM degradation. However, the turnover rate of MT1-MMP and the extent to which the turnover contributes to the ECM degradation at invadopodia have not been clarified. To approach this problem, we first performed FRAP (Fluorescence Recovery after Photobleaching) experiments with fluorescence-tagged MT1-MMP focusing on a single invadopodium and found very rapid recovery in FRAP signals, approximated by double-exponential plots with time constants of 26 s and 259 s. The recovery depended primarily on vesicle transport, but negligibly on lateral diffusion. Next we constructed a computational model employing the observed kinetics of the FRAP experiments. The simulations successfully reproduced our FRAP experiments. Next we inhibited the vesicle transport both experimentally, and in simulation. Addition of drugs inhibiting vesicle transport blocked ECM degradation experimentally, and the simulation showed no appreciable ECM degradation under conditions inhibiting vesicle transport. In addition, the degree of the reduction in ECM degradation depended on the degree of the reduction in the MT1-MMP turnover. Thus, our experiments and simulations have established the role of the rapid turnover of MT1-MMP in ECM degradation at invadopodia. Furthermore, our simulations suggested synergetic contributions of proteolytic activity and the MT1-MMP turnover to ECM degradation because there was a nonlinear and marked reduction in ECM degradation if both factors were reduced simultaneously. Thus our computational model provides a new in silico tool to design and evaluate intervention strategies in cancer cell invasion