We show that the recently observed superconductivity in twisted bilayer graphene (TBG) can be explained as a consequence of the Kohn-Luttinger (KL) instability which leads to an effective attraction ...between electrons with originally repulsive interaction. Usually, the KL instability takes place at extremely low energy scales, but in TBG, a doubling and subsequent strong coupling of the van Hove singularities (vHS) in the electronic spectrum occurs as the magic angle is approached, leading to extended saddle points in the highest valence band with almost perfect nesting between states belonging to different valleys. The highly anisotropic screening induces an effective attraction in a p-wave channel with odd parity under the exchange of the two disjoined patches of the Fermi line. We also predict the appearance of a spin-density wave instability, adjacent to the superconducting phase, and the opening of a gap in the electronic spectrum from the condensation of spins with wave vector corresponding to the nesting vector close to the vHS.
A critical look at how the US military is weaponizing
technology and data for new kinds of warfare-and why we must
resist. War Virtually is the story of how
scientists, programmers, and engineers are ...racing to develop
data-driven technologies for fighting virtual wars, both at home
and abroad. In this landmark book, Roberto J. González gives us a
lucid and gripping account of what lies behind the autonomous
weapons, robotic systems, predictive modeling software, advanced
surveillance programs, and psyops techniques that are transforming
the nature of military conflict. González, a cultural
anthropologist, takes a critical approach to the techno-utopian
view of these advancements and their dubious promise of a less
deadly and more efficient warfare. With clear, accessible prose,
this book exposes the high-tech underpinnings of contemporary
military operations-and the cultural assumptions they're built on.
Chapters cover automated battlefield robotics; social scientists'
involvement in experimental defense research; the blurred line
between political consulting and propaganda in the internet era;
and the military's use of big data to craft new counterinsurgency
methods based on predicting conflict. González also lays bare the
processes by which the Pentagon and US intelligence agencies have
quietly joined forces with Big Tech, raising an alarming prospect:
that someday Google, Amazon, and other Silicon Valley firms might
merge with some of the world's biggest defense contractors. War
Virtually takes an unflinching look at an algorithmic
future-where new military technologies threaten democratic
governance and human survival.
Antimicrobial resistance is one of the major problems in current practical medicine. The spread of genes coding for resistance determinants among bacteria challenges the use of approved antibiotics, ...narrowing the options for treatment. Resistance to carbapenems, last resort antibiotics, is a major concern. Metallo-β-lactamases (MBLs) hydrolyze carbapenems, penicillins, and cephalosporins, becoming central to this problem. These enzymes diverge with respect to serine-β-lactamases by exhibiting a different fold, active site, and catalytic features. Elucidating their catalytic mechanism has been a big challenge in the field that has limited the development of useful inhibitors. This review covers exhaustively the details of the active-site chemistries, the diversity of MBL alleles, the catalytic mechanism against different substrates, and how this information has helped developing inhibitors. We also discuss here different aspects critical to understand the success of MBLs in conferring resistance: the molecular determinants of their dissemination, their cell physiology, from the biogenesis to the processing involved in the transit to the periplasm, and the uptake of the Zn(II) ions upon metal starvation conditions, such as those encountered during an infection. In this regard, the chemical, biochemical and microbiological aspects provide an integrative view of the current knowledge of MBLs.
Highlights • We report real-world data from 464 patients treated with perampanel over 1 year. • Efficacy and tolerability of perampanel were comparable with clinical trial data. • Patients ≥65 years, ...vascular aetiology or fewer prior AEDs had a superior response. • Patients with psychiatric comorbidities (hyperactivity and personality disorder) were more likely to experience psychiatric AEs. • Patients with slower titration schedules were less likely to experience an AE
Using the fossil record method implemented through Pipe3D, we reconstruct the global and radial stellar mass growth histories (MGHs) of a large sample of galaxies, ranging from dwarf to giant ...objects, from the Mapping Nearby Galaxies at the Apache Point Observatory (MaNGA) survey. We confirm that the main driver of the global MGHs is mass, with more massive galaxies assembling earlier (downsizing), though for a given mass, the global MGHs segregate by colour, specific star formation rate and morphological type. From the inferred radial mean MGHs, we find that at fractions of assembled mass larger than ~80 per cent, the innermost regions formed stars, on average, in the inside-out mode. At earlier epochs, when the age estimation of the method becomes poor, the MGHs seem to be spatially homogeneous or even in the outside-in mode, especially for the red/quiescent/early-type galaxies. The innermost MGHs are, in general, less scattered around the mean than the outermost MGHs. For dwarf and low-mass galaxies, we do not find evidence of an outside-in formation mode; instead, their radial MGHs are very diverse most of the time, with periods of outside-in and inside-out modes (or strong radial migration), suggesting this is an episodic star formation history. Blue/star-forming/late-type galaxies present, on average, a significantly more pronounced inside-out formation mode than red/quiescent/early-type galaxies, independently of mass. We discuss our results in the light of the processes of galaxy formation, quenching and radial migration. We also discuss the uncertainties and biases of the fossil record method and how these could affect our results.
Composting has been traditionally considered a process in which a succession of mesophilic and thermophilic microbial populations occurs due to temperature changes. In order to deepen in this model, ...1380 bacterial and fungal strains (the entire culturable microbiota isolated from a composting process) were investigated for their ability to grow across a wide range of temperatures (20 to 60 °C). First, qualitative tests were performed to establish a thermal profile for each strain. Then, quantitative tests allowed ascertaining the extent of growth for each strain at each of the tested temperatures. The identity of the isolates enabled to position them taxonomically and permitted tracking the strains throughout the process. Results showed that 90% of the isolates were classified as thermotolerant (they grew at all tested temperatures). Only 9% and 1% of the studied strains showed to be strictly mesophilic or thermophilic, respectively. Firmicutes exhibited the greatest thermal plasticity, followed by Actinobacteria and Ascomycota. Most of the Proteobacteria and all Basidiomycota strains were also able to grow at all the assayed temperatures. Thermotolerance was clearly demonstrated among the composting microbiota, suggesting that the idea of the succession of mesophilic and thermophilic populations throughout the process might need a reassessment.
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•The temperature-driven succession of the composting microbial populations was revisited.•Thermotolerance was demonstrated for a vast majority of the composting microbiota.•Thermotolerant strains were repeatedly identified in most of the composting stages.•Firmicutes and Ascomycota accounted for the best represented thermotolerant phyla.•Thermal plasticity is a microbial reply to the ever changing composting conditions.
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