644 research outputs found
Hjarnø Sund – all year, all inclusive: A submerged Late Mesolithic coastal site with organic remains
Between 2009 and 2016, a series of investigations were undertaken at a submerged settlement of the island of Hjarnø in Horsens Fjord, Denmark. The work was prompted by the discovery in 2008 that heavy erosion of a gyttja deposit containing archaeological remains had resulted in artefacts of bone, antler and, not least, wood becoming exposed on the seabed. The investigations revealed that occupation of the site, with a few exceptions, dates to the first half of the Ertebølle culture (5400–4700 BC). In addition to numerous well-preserved artefacts made of organic materials, several areas were found to contain intact shell layers from submerged kitchen middens. Deposits of this kind have not previously been demonstrated in Denmark
Robust half-metallic antiferromagnets LaVOsO and LaMoO ( = Ca, Sr, Ba; = Re, Tc) from first-principles calculations
We have theoretically designed three families of the half-metallic (HM)
antiferromagnets (AFM), namely, LaVOsO, LaMoTcO and
LaMoReO ( = Ca, Sr, Ba), based on a systematic {\it ab initio} study
of the ordered double perovskites LaO with the possible and
pairs from all the 3, 4 and 5 transtion metal elements being
considered. Electronic structure calculations based on first-principles
density-functional theory with generalized gradient approximation (GGA) for
more than sixty double perovskites LaCaO have been performed using the
all-electron full-potential linearized augmented-plane-wave method. The found
HM-AFM state in these materials survives the full {\it ab initio} lattice
constant and atomic position optimizations which were carried out using
frozen-core full potential projector augmented wave method. It is found that
the HM-AFM properties predicted previously in some of the double perovskites
would disappear after the full structural optimizations. The AFM is attributed
to both the superexchange mechanism and the generalized double exchange
mechanism via the () - O (2) - () coupling
and the latter is also believed to be the origin of the HM. Finally, in our
search for the HM-AFMs, we find LaCrTcO and LaCrReO to be AFM
insulators of an unconventional type in the sense that the two
antiferromagnetic coupled ions consist of two different elements and that the
two spin-resolved densities of states are no longer the same.Comment: To appear in Phys. Rev.
LDA+DMFT computation of the electronic spectrum of NiO
The electronic spectrum, energy gap and local magnetic moment of paramagnetic
NiO are computed by using the local density approximation plus dynamical
mean-field theory (LDA+DMFT). To this end the noninteracting Hamiltonian
obtained within the local density approximation (LDA) is expressed in Wannier
functions basis, with only the five anti-bonding bands with mainly Ni 3d
character taken into account. Complementing it by local Coulomb interactions
one arrives at a material-specific many-body Hamiltonian which is solved by
DMFT together with quantum Monte-Carlo (QMC) simulations. The large insulating
gap in NiO is found to be a result of the strong electronic correlations in the
paramagnetic state. In the vicinity of the gap region, the shape of the
electronic spectrum calculated in this way is in good agreement with the
experimental x-ray-photoemission and bremsstrahlung-isochromat-spectroscopy
results of Sawatzky and Allen. The value of the local magnetic moment computed
in the paramagnetic phase (PM) agrees well with that measured in the
antiferromagnetic (AFM) phase. Our results for the electronic spectrum and the
local magnetic moment in the PM phase are in accordance with the experimental
finding that AFM long-range order has no significant influence on the
electronic structure of NiO.Comment: 15 pages, 6 figures, 1 table; published versio
Compositional disorder and its influence on the structural, electronic and magnetic properties of MgC(Ni_{1-x}Co_{x})_{3} alloys using first-principles
First-principles, density-functional based electronic structure calculations
are carried out for MgC(Ni_{1-x}Co_{x})_{3} alloys over the concentration range
0\leq x\leq1, using Korringa-Kohn-Rostoker coherent-potential approximation
(KKR CPA) method in the atomic sphere approximation (ASA). The self-consistent
calculations are used to study the changes as a function of x in the equation
of state parameters, total and partial densities of states, magnetic moment and
the on-site exchange interaction parameter. To study the magnetic properties as
well as its volume dependence, fixed-spin moment calculations in conjunction
with the phenomenological Landau theory are employed. The salient features that
emerge from these calculations are (i) a concentration independent variation in
the lattice parameter and bulk modulus at x~0.75 with an anomaly in the
variation of the pressure derivative of bulk modulus, (ii) the fixed-spin
moment based corrections to the overestimated magnetic ground state for 0.0\leq
x\leq0.3 alloys, making the results consistent with the experiments, and (iii)
the possibility of multiple magnetic states at x~0.75, which, however, requires
further improvements in the calculations
Does Training and Support of General Practitioners in Intensive Treatment of People with Screen-Detected Diabetes Improve Medication, Morbidity and Mortality in People with Clinically-Diagnosed Diabetes? Investigation of a Spill-Over Effect in a Cluster RCT
Very few studies have examined the potential spill-over effect of a trial intervention in general practice. We investigated whether training and support of general practitioners in the intensive treatment of people with screen-detected diabetes improved rates of redeemed medication, morbidity and mortality in people with clinically-diagnosed diabetes.
This is a secondary, post-hoc, register-based analysis linked to a cluster randomised trial. In the trial, 175 general practices were cluster randomised (i) to routine care, or (ii) to receive training and support in intensive multifactorial treatment of individuals with screen-detected diabetes (2001 to 2009). Using national registers we identified all individuals who were diagnosed with clinically incident diabetes in the same practices over the same time period. (Patients participating in the ADDITION trial were excluded). We compared rates of redeemed medication, a cardiovascular composite endpoint, and all-cause mortality between the routine care and intensive treatment groups.
In total, 4,107 individuals were diagnosed with clinically incident diabetes in practices between 2001 and 2009 (2,051 in the routine care group and 2,056 in the intensive treatment group). There were large and significant increases in the proportion of patients redeeming cardio-protective medication in both treatment groups during follow- up. After a median of seven years of follow-up, there was no difference in the incidence of a composite cardiovascular endpoint (HR 1.15, 95% CI 0.95 to 1.38) or all-cause mortality between the two groups (HR 1.08, 95% CI 0.94 to 1.23).
There was no evidence of a spill-over effect from an intervention promoting intensive treatment of people with screen-detected diabetes to those with clinically-diagnosed diabetes. Overall, the proportion of patients redeeming cardio-protective medication during follow-up was similar in both groups.
ClinicalTrials.gov NCT00237549Novo Nordisk Foundation (Grant ID: NNF14OC0008981
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