Superconductivity in chromium nitrides Pr3Cr10-xN11 with strong electron correlations

Exploration of superconductivity in Cr-based compounds has attracted considerable interest because only a few Cr-based superconductors (CrAs, A2Cr3As3 and ACr3As3 (A = K, Rb, Cs, Na)) have been discovered so far and they show an unconventional pairing mechanism. We report the discovery of bulk superconductivity at 5.25 K in chromium nitride in Pr3Cr10-xN11 with a cubic lattice structure. A relatively large upper critical field of Hc2(0) ∼ 12.6 T is determined, which is larger than the estimated Pauli-paramagnetic pair-breaking magnetic field. The material has a large electronic specific-heat coefficient of 170 mJ K−2 mol−1—about 10 times larger than that estimated by the electronic structure calculation, which suggests that correlations between 3d electrons are very strong in Pr3Cr10-xN11, and thus quantum fluctuations might be involved. Electronic structure calculations show that the density of states at the Fermi energy are contributed predominantly by Cr 3d electrons, implying that the superconductivity results mainly from the condensation of Cr 3d electrons. Pr3Cr10-xN11 represents a rare example of possible unconventional superconductivity emerging in a 3D system with strong electron correlations. Nevertheless, clarification of the specific pairing symmetry needs more investigation.

CAVE: Making Collective Virtual Narrative: Best Paper Award

CAVE is a shared narrative six degrees of freedom (6DoF) virtual reality experience. In 3.5 days, 1,927 people attended its premiere at SIGGRAPH 2018. Thirty participants at a time each saw and heard the same narrative from their own individual location in the room, as they would when attending live theater. CAVE set out to disruptively change how audiences collectively experience immersive art and entertainment. Inspired by the social gatherings of theater and cinema, CAVE resonated with viewers in powerful and meaningful ways. Its specific pairing of colocated audiences and physically shared immersive narrative suggests a possible future path for shared cinematic experiences.

German multiple fronting and expected topic-hood

This papers addresses information-structural restrictions on the occurrence of what is known as "multiple fronting" in German. Multiple fronting involves the realization of (what appears to be) more than one constituent in the first position of main clause declaratives, a clause type that otherwise respects the verb-second constraint of German. Relying on a large body of naturally occurring instances of multiple fronting with the surrounding discourse context, we show that in certain contexts, multiple fronting is fully grammatical in German, in contrast to what has sometimes been claimed previously. Examination of this data reveals two different patterns, which we analyze in terms of two distinct constructions, each instantiating a specific pairing of form, meaning and contextual appropriateness.

For the Record: The Francis Crick Archive at the Wellcome Library

“This is an historic occasion”, announced Francis Crick on 2 June 1966, as he began the opening address of the annual meeting of molecular biologists at Cold Spring Harbor. “There have been many meetings”, he continued, “about the genetic code during the past ten or twelve years but this is the first important one to be held since the code became known.” Such bold pronouncements usually guarantee that an occasion will linger in history's footnotes and never shine centre-page. But, as the first public presentation of the complete genetic code, the moment had some claim to being historically complementary to the publication of James Watson and Crick's first paper in Nature. In April 1953, in fourteen paragraphs and a diagrammatic sketch (contributed by Odile Crick), they had announced—with a minimalism that came more of urgent certainty than of diffidence or reticence—not just a physical structure for DNA, but something far more. “It has not escaped our notice that the specific pairing [of purine and pyrimidine bases] we have postulated immediately suggests a possible copying mechanism for the genetic material.” The trajectory begun in 1953 with the suggestion of “a possible copying mechanism” completed its public arc at Cold Spring Harbor in 1966 with a very specific and (almost) complete table showing the genetic code. The occasion “marked”, as Crick later judged, “the end of classical molecular biology”.

Hybrids involving wheat relatives and autotetraploid Triticum umbellulatum

Genomic analysis based on chromosome pairing is perhaps the most reliable method of determining the major evolutionary pathways in allopolyploid series. Difficulties can arise when genomes have become modified, since then they will not correspond exactly to the genomes used as analysers. Some resolution of this type of problem is possible when the interpretation of meiotic data is enhanced by numerical methods. However, providing conclusive evidence of which chromosomes are pairing rather than just how many remains a problem unless specific chromosomes can be recognized. One possible solution is to make hybrids between natural polyploids and autotetraploids of the putative diploid progenitors. The recognition of specific pairing patterns in such hybrids will provide substantial evidence of which chromosomes are pairing at metaphase I. Hybrids between an autotetraploid Triticum umbellulatum and the natural U-genome polyploids T. kotschyi, T. neglecta, T. ovatum, T. macrochaetum, T. columnare, T. triunciale, and T. juvenale demonstrate that the U-genome of most of them is very closely related to the U-genome of the diploid T. umbellulatum. The U-genome in four hybrids in two accessions of T. ovatum does differ from its diploid progenitor, T. columnare shows some heterogeneity, and T. juvenale may show differentiation.Key words: autotetraploid, evolution, genome analysis, Triticum species, pivotal–differential evolution.