3,684 research outputs found
Doping Evolution of Magnetic Order and Magnetic Excitations in (SrLa)IrO
We use resonant elastic and inelastic X-ray scattering at the Ir- edge
to study the doping-dependent magnetic order, magnetic excitations and
spin-orbit excitons in the electron-doped bilayer iridate
(SrLa)IrO (). With increasing
doping , the three-dimensional long range antiferromagnetic order is
gradually suppressed and evolves into a three-dimensional short range order
from to , followed by a transition to two-dimensional short range
order between and . Following the evolution of the
antiferromagnetic order, the magnetic excitations undergo damping, anisotropic
softening and gap collapse, accompanied by weakly doping-dependent spin-orbit
excitons. Therefore, we conclude that electron doping suppresses the magnetic
anisotropy and interlayer couplings and drives
(SrLa)IrO into a correlated metallic state hosting
two-dimensional short range antiferromagnetic order and strong
antiferromagnetic fluctuations of moments, with
the magnon gap strongly suppressed.Comment: 6 Pages, 3 Figures, with supplementary in Sourc
Neonatal abstinence syndrome.
A 12 month review of infants admitted with neonatal abstinence syndrome to a neonatal intensive care unit was undertaken. The relationship of maternal drug abuse to symptoms, the effectiveness of pharmacologic agents in controlling symptoms and the length of inpatient stay were investigated.
A retrospective review of maternal and infant records was performed. Those infants with a serial Finnegan score greater than 8 were treated. Pharmacologic treatment was oral morphine sulphate (0.2 mg 4-6 hourly), phenobarbitone (3-7 mgs/kg/day), or combination of the above. 43 infants were admitted to the hospital during the year. The average maternal age was 24.6 years, (18-34 years). Drug use volunteered by the mothers was methadone alone in 6 cases, methadone and benzodiazepines in 14, methadone and heroin and benzodiazepines in 7, methadone and heroin in 10, heroin alone in 2, and other multiple drug use including oral morphine sulphate, dothiepin and cannabis in 4.
Average gestational age was 40.3 (35-42 weeks). The average birthweight was 2.81 kgs (1.89-3.91 kgs). Time to onset of withdrawal symptoms was 2.8 (1-13) days. The duration of pharmacologic treatment (oral morphine sulphate and/or phenobarbitone) was 21.8 (1-62) days. The total hospital stay for the 43 infants was 1,011 days. This study confirms that polydrug abuse is the commonest type of drug abuse in Dublin. The duration of withdrawal symptoms is loosely related to drug type, but increasing duration of symptoms is noted for infants exposed to benzodiazepines. Our experience would favour the use of morphine sulphate to treat pure opiate withdrawal symptoms. Over the 12-month period, there was an average occupancy of 3 beds per day in the paediatric department
Resolving the nature of electronic excitations in resonant inelastic x-ray scattering
The study of elementary bosonic excitations is essential toward a complete
description of quantum electronic solids. In this context, resonant inelastic
X-ray scattering (RIXS) has recently risen to becoming a versatile probe of
electronic excitations in strongly correlated electron systems. The nature of
the radiation-matter interaction endows RIXS with the ability to resolve the
charge, spin and orbital nature of individual excitations. However, this
capability has been only marginally explored to date. Here, we demonstrate a
systematic method for the extraction of the character of excitations as
imprinted in the azimuthal dependence of the RIXS signal. Using this novel
approach, we resolve the charge, spin, and orbital nature of elastic
scattering, (para-)magnon/bimagnon modes, and higher energy dd excitations in
magnetically-ordered and superconducting copper-oxide perovskites (Nd2CuO4 and
YBa2Cu3O6.75). Our method derives from a direct application of scattering
theory, enabling us to deconstruct the complex scattering tensor as a function
of energy loss. In particular, we use the characteristic tensorial nature of
each excitation to precisely and reliably disentangle the charge and spin
contributions to the low energy RIXS spectrum. This procedure enables to
separately track the evolution of spin and charge spectral distributions in
cuprates with doping. Our results demonstrate a new capability that can be
integrated into the RIXS toolset, and that promises to be widely applicable to
materials with intertwined spin, orbital, and charge excitations
Electronic and magnetic excitations in the "half-stuffed" Cu--O planes of BaCuOCl measured by resonant inelastic x-ray scattering
We use resonant inelastic x-ray scattering (RIXS) at the Cu L edge to
measure the charge and spin excitations in the "half-stuffed" Cu--O planes of
the cuprate antiferromagnet BaCuOCl. The RIXS line shape
reveals distinct contributions to the excitations from the two
structurally inequivalent Cu sites, which have different out-of-plane
coordinations. The low-energy response exhibits magnetic excitations. We find a
spin-wave branch whose dispersion follows the symmetry of a CuO sublattice,
similar to the case of the "fully-stuffed" planes of tetragonal CuO (T-CuO).
Its bandwidth is closer to that of a typical cuprate material, such as
SrCuOCl, than it is to that of T-CuO. We interpret this result as
arising from the absence of the effective four-spin inter-sublattice
interactions that act to reduce the bandwidth in T-CuO.Comment: 10 pages, 8 figure
Technologies for restricting mould growth on baled silage
End of project reportSilage is made on approximately 86% of Irish farms, and 85% of these make some baled silage. Baled silage is particularly important as the primary silage making, storage and feeding system on many beef and smaller sized farms, but is also employed as a secondary system (often associated with facilitating grazing management during mid-summer) on many dairy and larger sized farms (O’Kiely et al., 2002). Previous surveys on farms indicated that the extent of visible fungal growth on baled silage was sometimes quite large, and could be a cause for concern. Whereas some improvements could come from applying existing knowledge and technologies, the circumstances surrounding the making and storage of baled silage suggested that environmental conditions within the bale differed from those in conventional silos, and that further knowledge was required in order to arrive at a secure set of recommendations for baled silage systems. This report deals with the final in a series (O’Kiely et al., 1999; O’Kiely et al., 2002) of three consecutive research projects investigating numerous aspect of the science and technology of baled silage. The success of each depended on extensive, integrated collaboration between the Teagasc research centres at Grange and Oak Park, and with University College Dublin. As the series progressed the multidisciplinary team needed to underpin the programme expanded, and this greatly improved the amount and detail of the research undertaken. The major objective of the project recorded in this report was to develop technologies to improve the “hygienic value” of baled silage
Magnetic structure of Yb2Pt2Pb: Ising moments on the Shastry-Sutherland lattice.
Neutron diffraction measurements were carried out on single crystals and powders of Yb2Pt2Pb, where Yb moments form two interpenetrating planar sublattices of orthogonal dimers, a geometry known as Shastry-Sutherland lattice, and are stacked along the c axis in a ladder geometry. Yb2Pt2Pb orders antiferromagnetically at TN=2.07K, and the magnetic structure determined from these measurements features the interleaving of two orthogonal sublattices into a 5×5×1 magnetic supercell that is based on stripes with moments perpendicular to the dimer bonds, which are along (110) and (−110). Magnetic fields applied along (110) or (−110) suppress the antiferromagnetic peaks from an individual sublattice, but leave the orthogonal sublattice unaffected, evidence for the Ising character of the Yb moments in Yb2Pt2Pb that is supported by point charge calculations. Specific heat, magnetic susceptibility, and electrical resistivity measurements concur with neutron elastic scattering results that the longitudinal critical fluctuations are gapped with ΔE≃0.07meV
Highly conductive Sb-doped layers in strained Si
The ability to create stable, highly conductive ultrashallow doped regions is a key requirement for future silicon-based devices. It is shown that biaxial tensile strain reduces the sheet resistance of highly doped n-type layers created by Sb or As implantation. The improvement is stronger with Sb, leading to a reversal in the relative doping efficiency of these n-type impurities. For Sb, the primary effect is a strong enhancement of activation as a function of tensile strain. At low processing temperatures, 0.7% strain more than doubles Sb activation, while enabling the formation of stable, ~10-nm-deep junctions. This makes Sb an interesting alternative to As for ultrashallow junctions in strain-engineered complementary metal-oxide-semiconductor device
Evaluational adjectives
This paper demarcates a theoretically interesting class of "evaluational adjectives." This class includes predicates expressing various kinds of normative and epistemic evaluation, such as predicates of personal taste, aesthetic adjectives, moral adjectives, and epistemic adjectives, among others. Evaluational adjectives are distinguished, empirically, in exhibiting phenomena such as discourse-oriented use, felicitous embedding under the attitude verb `find', and sorites-susceptibility in the comparative form. A unified degree-based semantics is developed: What distinguishes evaluational adjectives, semantically, is that they denote context-dependent measure functions ("evaluational perspectives")—context-dependent mappings to degrees of taste, beauty, probability, etc., depending on the adjective. This perspective-sensitivity characterizing the class of evaluational adjectives cannot be assimilated to vagueness, sensitivity to an experiencer argument, or multidimensionality; and it cannot be demarcated in terms of pretheoretic notions of subjectivity, common in the literature. I propose that certain diagnostics for "subjective" expressions be analyzed instead in terms of a precisely specified kind of discourse-oriented use of context-sensitive language. I close by applying the account to `find x PRED' ascriptions
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