474 research outputs found
Humanitarian aid as an integral part of the European Union's external action: the challenge of reconciling coherence and independence
The article focuses on the European Union's (EU) humanitarian aid policy. It addresses the challenge for the EU to deliver independent humanitarian aid while simultaneously seeking to establish more coherence between its external policies. The article examines how the EU tries to reconcile these potentially conflicting policy goals, both de jure and in practice. Empirically, it explores the interaction between EU humanitarian aid and development cooperation, the Common Foreign and Security Policy, and trade policy. While the independence of the humanitarian aid delivery is, for the most part, not being undermined, it remains difficult to establish positive synergies with other external policies because of institutional hurdles and legal constraints, as well as political obstacles and operational incompatibilities
Momentum-resolved lattice dynamics of parent and electron-doped SrIrO
The mixing of orbital and spin character in the wave functions of the
iridates has led to predictions of strong couplings among their lattice,
electronic and magnetic degrees of freedom. As well as realizing a novel
spin-orbit assisted Mott-insulating ground state, the perovskite iridate
SrIrO has strong similarities with the cuprate LaCuO,
which on doping hosts a charge-density wave that appears intimately connected
to high-temperature superconductivity. These phenomena can be sensitively
probed through momentum-resolved measurements of the lattice dynamics, made
possible by meV-resolution inelastic x-ray scattering. Here we report the first
such measurements for both parent and electron-doped SrIrO. We find
that the low-energy phonon dispersions and intensities in both compounds are
well described by the same nonmagnetic density functional theory calculation.
In the parent compound, no changes of the phonons on magnetic ordering are
discernible within the experimental resolution, and in the doped compound no
anomalies are apparent due to charge-density waves. These measurements extend
our knowledge of the lattice properties of (SrLa)IrO
and constrain the couplings of the phonons to magnetic and charge order.Comment: 8 pages, 6 figures (+ 12 pages, 6 figures of supplemental material
Correlated electron metal properties of the honeycomb ruthenate Na₂RuO₃
We report the synthesis and characterization of polycrystalline Na_{2}RuO_{3}, a layered material in which the Ru^{4+} (4d^{4} configuration) form a honeycomb lattice. The optimal synthesis condition was found to produce a nearly ordered Na_{2}RuO_{3} (C2/c phase), as assessed from the refinement of the time-of-flight neutron powder diffraction. Magnetic susceptibility measurements reveal a large temperature-independent Pauli paramagnetism [x_{0} ~ 1.42(2) x 10^{-3} emu/mol Oe] with no evidence of magnetic ordering down to 1.5 K, and with an absence of dynamic magnetic correlations, as evidenced by neutron scattering spectroscopy. The intrinsic susceptibility (x_{0}) together with the Sommerfeld coefficient of gamma = 11.7(2) mJ/Ru mol K^{2} estimated from heat capacity measurements gives an enhanced Wilson ratio of R_{w} ≈ 8.9(1), suggesting that magnetic correlations may be present in this material. While transport measurements on pressed pellets show nonmetallic behavior, photoemission spectroscopy indicates a small but finite density of states at the Fermi energy, suggesting that the bulk material is metallic. Except for resistivity measurements, which may have been compromised by near-surface and interface effects, all other probes indicate that Na_{2}RuO_{3} is a moderately correlated electron metal. Our results thus stand in contrast to earlier reports that Na_{2}RuO_{3} is an antiferromagnetic insulator at low temperatures
Understanding experiences of Aboriginal and/or Torres Strait Islander patients at the emergency departments in Australia
Objectives: The present study describes the experiences of Aboriginal and/or Torres Strait Islander patients and the factors that shaped their experiences of ED visits in regional settings. Methods: This is a qualitative descriptive study. We conducted semi-structured in-depth interviews with Aboriginal and/or Torres Strait Islander patients who used the ED services at three hospitals in New South Wales, Northern Territory and South Australia. We coded the collected data and analysed them using a thematic analysis technique. Results: A total of 33 Aboriginal and/or Torres Strait Islander patients participated. Analyses of their experiences revealed four themes, which included: (i) patients' waiting times in ED; (ii) cultural determinants of health; (iii) treatment services; and (iv) safety, security and privacy. Conclusions: A holistic approach and a robust hospital commitment to address cultural needs while considering overall health, social and emotional wellbeing, will enhance Aboriginal and/or Torres Strait Islander patients' satisfaction for ED visits
New Compact Object Binary Populations with Precision Astrometry (Roman White Paper)
Compact object binaries (a black hole or a neutron star orbiting a
non-degenerate stellar companion) are key to our understanding of late massive
star evolution, in addition to being some of the best probes of extreme gravity
and accretion physics. Gaia has opened the door to astrometric studies of these
systems, enabling geometric distance measurements, kinematic estimation, and
the ability to find new previously unknown systems through measurement of
binary orbital elements. Particularly puzzling are newly found massive black
holes in wide orbits (~AU or more) whose evolutionary history is difficult to
explain. Astrometric identification of such binaries is challenging for Gaia,
with only two such examples currently known. Roman's enormous grasp, superb
sensitivity, sharp PSF and controlled survey strategy can prove to be a
game-changer in this field, extending astrometric studies of compact object
binaries several mag deeper than Gaia. We propose to use the microlensing
Galactic Bulge Time Domain Survey to identify new wide-orbit black hole compact
object binaries, determine their prevalence and their spatial distribution,
thus opening up new parameter space in binary population studies.Comment: Submitted to the Nancy Grace Roman Space Telescope CCS White Paper
call (4.5 pages of text + figures, references and a cover sheet).
Comments/collaboration welcom
High-resolution resonant inelastic x-ray scattering study of the electron-phonon coupling in honeycomb α-Li₂IrO₃
The excitations in honeycomb
α
−
Li
2
IrO
3
have been investigated with high-resolution resonant inelastic x-ray scattering (RIXS) at the O
K
edge. The low-energy response is dominated by a fully resolved ladder of excitations, which we interpret as being due to multiphonon processes in the presence of strong electron-phonon coupling (EPC). At higher energies, the orbital excitations are shown to be dressed by phonons. The high quality of the data permits a quantitative test of the analytical model for the RIXS cross section, which has been proposed to describe EPC in transition-metal oxides (TMOs). We find that the magnitude of the EPC is comparable to that found for a range of
3
d
TMOs. This indicates that EPC may be of equal importance in determining the phenomenology displayed by corresponding
5
d
-based systems
Correlated electron metal properties of the honeycomb ruthenate NaRuO
We report the synthesis and characterisation of polycrystalline
NaRuO, a layered material in which the Ru ( configuration)
form a honeycomb lattice. The optimal synthesis condition was found to produce
a nearly ordered NaRuO ( phase), as assessed from the refinement
of the time-of-flight neutron powder diffraction. Magnetic susceptibility
measurements reveal a large temperature-independent Pauli paramagnetism
( emu/mol Oe) with no evidence of magnetic
ordering down to 1.5 K, and with an absence of dynamic magnetic correlations,
as evidenced by neutron scattering spectroscopy. The intrinsic susceptibility
() together with the Sommerfeld coeficient of mJ/Ru
mol K estimated from heat capacity measurements, gives an enhanced Wilson
ratio of , suggesting that magnetic correlations may be
present in this material. While transport measurements on pressed pellets show
nonmetallic behaviour, photoemission spectrocopy indicate a small but finite
density of states at the Fermi energy, suggesting that the bulk material is
metallic. Except for resistivity measurements, which may have been compromised
by near surface and interface effects, all other probes indicate that
NaRuO is a moderately correlated electron metal. Our results thus stand
in contrast to earlier reports that NaRuO is an antiferromagnetic
insulator at low temperatures.Comment: 9 pages, 6 figure
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