24 research outputs found
Hydrogen accommodation in Zr second phase particles: Implications for H pick-up and hydriding of Zircaloy-2 and Zircaloy-4
Ab-initio computer simulations have been used to predict the energies
associated with the accommodation of H atoms at interstitial sites in {\alpha},
{\beta}-Zr and Zr.M intermetallics formed with common alloying additions (M =
Cr, Fe, Ni). Intermetallics that relate to the Zr2(Ni,Fe) second phase
particles (SPPs) found in Zircaloy-2 exhibit favourable solution enthalpies for
H. The intermetallic phases that relate to the Zr(Cr,Fe)2 SPPs, found
predominantly in Zircaloy-4, do not offer favourable sites for interstitial H.
It is proposed that Zr(Cr,Fe)2 particles may act as bridges for the migration
of H through the oxide layer, whilst the Zr2(Ni,Fe)-type particles will trap
the migrating H until these are dissolved or fully oxidised
Associations of autozygosity with a broad range of human phenotypes
In many species, the offspring of related parents suffer reduced reproductive success, a phenomenon known as inbreeding depression. In humans, the importance of this effect has remained unclear, partly because reproduction between close relatives is both rare and frequently associated with confounding social factors. Here, using genomic inbreeding coefficients (F-ROH) for >1.4 million individuals, we show that F-ROH is significantly associated (p <0.0005) with apparently deleterious changes in 32 out of 100 traits analysed. These changes are associated with runs of homozygosity (ROH), but not with common variant homozygosity, suggesting that genetic variants associated with inbreeding depression are predominantly rare. The effect on fertility is striking: F-ROH equivalent to the offspring of first cousins is associated with a 55% decrease [95% CI 44-66%] in the odds of having children. Finally, the effects of F-ROH are confirmed within full-sibling pairs, where the variation in F-ROH is independent of all environmental confounding.Peer reviewe
Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.
BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362
Assessing biomass based on canopy height profiles using airborne laser scanning data in eucalypt plantations
The thermodynamics of hydride precipitation: the importance of entropy, enthalpy and disorder
The thermodynamics of H/{\alpha}-Zr solid solution and zirconium hydride
phases were studied using density functional theory. Disorder in {\zeta},
{\gamma} and {\delta} hydrides and solid solutions were modelled using a
statistically significant number of randomly generated structures in
combination with special quasi-random structures and solid solutions with a
range of concentrations. This is used in conjunction with a calculation of
thermodynamic parameters of the system, including the temperature dependent
sensible enthalpy, configurational entropy and vibrational entropy of the
different crystals in the system, developed from phonon density of states. It
was found that precipitation of hydrides is not thermodynamically favourable
for Zr-H solid solutions containing less than 300 ppm H, suggesting that a
mechanism must cause local concentration of H atoms to a greater amount than
found globally in experimental samples containing hydrides. Temperature drives
the reaction in the direction of solution, primarily due to entropic effects.
Generally, {\gamma} hydride is the most stable phase, although it is very close
in energy to the {\delta}-phase. The sensible enthalpy of precipitation assists
in stabilising HCP hydrides, and the configurational entropy change during
precipitation favours FCC hydrides. None of the thermodynamic contributions are
found to be negligible in driving precipitation.Comment: 19 pages, 11 figures, submitted to Phys. Rev. B on 22-Jan-201