Orbital order in the low-dimensional quantum spin system TiOCl probed by ESR

We present electron spin resonance data of Ti$^{3+}$ (3$d^1$) ions in single crystals of the novel layered quantum spin magnet TiOCl. The analysis of the g tensor yields direct evidence that the d_{xy} orbital from the t_{2g} set is predominantly occupied and owing to the occurrence of orbital order a linear spin chain forms along the crystallographic b axis. This result corroborates recent theoretical LDA+U calculations of the band structure. The temperature dependence of the parameters of the resonance signal suggests a strong coupling between spin and lattice degrees of freedom and gives evidence for a transition to a nonmagnetic ground state at 67 K.Comment: revised version, accepted for publication in Phys. Rev. B, Rapid Com

Galaxy bulges and their massive black holes: a review

With references to both key and oft-forgotten pioneering works, this article starts by presenting a review into how we came to believe in the existence of massive black holes at the centres of galaxies. It then presents the historical development of the near-linear (black hole)-(host spheroid) mass relation, before explaining why this has recently been dramatically revised. Past disagreement over the slope of the (black hole)-(velocity dispersion) relation is also explained, and the discovery of sub-structure within the (black hole)-(velocity dispersion) diagram is discussed. As the search for the fundamental connection between massive black holes and their host galaxies continues, the competing array of additional black hole mass scaling relations for samples of predominantly inactive galaxies are presented.Comment: Invited (15 Feb. 2014) review article (submitted 16 Nov. 2014). 590 references, 9 figures, 25 pages in emulateApJ format. To appear in "Galactic Bulges", E. Laurikainen, R.F. Peletier, and D.A. Gadotti (eds.), Springer Publishin

New Blood Pressure-Associated Loci Identified in Meta-Analyses of 475,000 Individuals

Background - Genome-wide association studies have recently identified >400 loci that harbor DNA sequence variants that influence blood pressure (BP). Our earlier studies identified and validated 56 single nucleotide variants (SNVs) associated with BP from meta-analyses of exome chip genotype data. An additional 100 variants yielded suggestive evidence of association. Methods and Results - Here, we augment the sample with 140 886 European individuals from the UK Biobank, in whom 77 of the 100 suggestive SNVs were available for association analysis with systolic BP or diastolic BP or pulse pressure. We performed 2 meta-analyses, one in individuals of European, South Asian, African, and Hispanic descent (pan-ancestry, ≈475 000), and the other in the subset of individuals of European descent (≈423 000). Twenty-one SNVs were genome-wide significant (P<5×10-8) for BP, of which 4 are new BP loci: rs9678851 (missense, SLC4A1AP), rs7437940 (AFAP1), rs13303 (missense, STAB1), and rs1055144 (7p15.2). In addition, we identified a potentially independent novel BP-associated SNV, rs3416322 (missense, SYNPO2L) at a known locus, uncorrelated with the previously reported SNVs. Two SNVs are associated with expression levels of nearby genes, and SNVs at 3 loci are associated with other traits. One SNV with a minor allele frequency <0.01, (rs3025380 at DBH) was genome-wide significant. Conclusions - We report 4 novel loci associated with BP regulation, and 1 independent variant at an established BP locus. This analysis highlights several candidate genes with variation that alter protein function or gene expression for potential follow-up

Repositioning of the global epicentre of non-optimal cholesterol

High blood cholesterol is typically considered a feature of wealthy western countries1,2. However, dietary and behavioural determinants of blood cholesterol are changing rapidly throughout the world3 and countries are using lipid-lowering medications at varying rates. These changes can have distinct effects on the levels of high-density lipoprotein (HDL) cholesterol and non-HDL cholesterol, which have different effects on human health4,5. However, the trends of HDL and non-HDL cholesterol levels over time have not been previously reported in a global analysis. Here we pooled 1,127 population-based studies that measured blood lipids in 102.6 million individuals aged 18 years and older to estimate trends from 1980 to 2018 in mean total, non-HDL and HDL cholesterol levels for 200 countries. Globally, there was little change in total or non-HDL cholesterol from 1980 to 2018. This was a net effect of increases in low- and middle-income countries, especially in east and southeast Asia, and decreases in high-income western countries, especially those in northwestern Europe, and in central and eastern Europe. As a result, countries with the highest level of non-HDL cholesterol—which is a marker of cardiovascular risk—changed from those in western Europe such as Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland and Malta in 1980 to those in Asia and the Pacific, such as Tokelau, Malaysia, The Philippines and Thailand. In 2017, high non-HDL cholesterol was responsible for an estimated 3.9 million (95% credible interval 3.7 million–4.2 million) worldwide deaths, half of which occurred in east, southeast and south Asia. The global repositioning of lipid-related risk, with non-optimal cholesterol shifting from a distinct feature of high-income countries in northwestern Europe, north America and Australasia to one that affects countries in east and southeast Asia and Oceania should motivate the use of population-based policies and personal interventions to improve nutrition and enhance access to treatment throughout the world.</p

MULTI-DIMENSIONAL ELECTRONIC AND NUCLEAR COORDINATES INFLUENCING LASING ACTION

The easy, and some far more counterintuitive, parts of quantum mechanics are analyzed for monatomic ions ; for the time independent Schrödinger solution for a given set of N nuclei and a number of electrons ; and if the Born-Oppenheimer factorization is acceptable, the (3N-5) dimensional potential surfaces of each electronic state are significant for Stokes shifts of asymmetric luminescence bands, and unexpected shape and positions of new absorption bands due to laser-induced quasi-stationary small concentrations of a low-symmetry excited state

ACCESS OF EXCITED STATES TO THE CONTINUUM

La désexcitation non-radiative des niveaux J de lanthanides trivalents en matière condensée est discutée en relation avec un fond continu (au-dessus 2 eV) trouvé dans des molécules simples et dans l'eau liquide.The non-radiative relaxation of excited J-levels of trivalent lanthanides in condensed matter is discussed, with emphasis on a weak continuous background above 2 eV found in simple molecules and in liquid water

Excited states of cerium (III) in various local symmetries by UV absorption and luminescence spectra

Among trivalent lanthanides, cerium has the lowest-lying 5dl configuration with up to five distinct Kramers doublet energies, strongly separated by chemical bonding of the same kind as known from Re, Os, Ir, Pt complexes with ground configuration 5dq, but with more moderate spin-orbit coupling effects in Ce. Lanthanides rather indifferently show all the coordination numbers N from 6 to 12 (11 for CeF3) and elastic internuclear distances. Stokes shifts can only be superficially rationalized with one configurational coordinate out of many

LUMINESCENCE IN POTENTIAL FLUORIDE GLASS LASERS

Fluoride glasses of the zirconium barium lanthanide type (invented Rennes, 1975) and lead gallium zinc (or manganese) type (invented Le Mans, 1979) show luminescence of lanthanide J-Levels situated at least 2000 cm-1 above the closest lower level (this limit is a few times larger in most other materials). Not only is the non-radiative de-excitation as weak as incrystalline LaF3 (studied by Weber) but energy transfer between neodymium and ytterbium (III), or from manganese (II), and to some extent from chromium (III), to luminescent J-levels of neodymium (III), erbium(III) and thulium (III) is highly efficient even at low concentrations. One advantage for laser applications is that the lowest quartet state of manganese (II) has a life-time 10 to 15 milliseconds (like in many phosphate glasses and crystalline compounds) allowing energy transfer, extending by huge factors the average life-time of the emitting J-levels. Though the terawatt lasers (Livermore, California, 1978) inducing deuterium-tritium fusion are silicate glass containing neodymium (III), fluoride glasses should be preferable for many purposes. The evaluation of laser parameters from small-scale experimentation is feasible