1,369 research outputs found
Near-IR Spectropolarimetry of NGC 1088
Original paper can be found at: http://www.astrosociety.org/pubs/cs/035-069.html--Copyright Astronomical Society of the PacificThe current unified model of Seyfert galaxies, as proposed by Antonucci and Miller (1985), has most, if not all, Seyfert 2 galaxies hosting a Seyfert 1 type nucleus in their cores. The broad lines from the type 1 nucleus can be scattered and be seen in the polarized flux spectrum, provided the geometry is correct. Whether the mechanism is electron or dust scattering has been a question of some debate. Since dust would normally have a low scattering efficiency in the infrared, near-IR spectropolarimetry should help in determing the nature of the scatterers. To this end we present the first near-IR spectropolarimetry of NGC 1068 a "Seyfert 2" galaxy in which polarized broad lines have been observed at optical wavelengths
Synthesis and Characterization of Brannerite Wasteforms for the Immobilization of Mixed Oxide Fuel Residues
A possible method for the reduction of civil Pu stockpiles is the reuse of Pu in mixed oxide fuel (MOX). During MOX fuel production, residues unsuitable for further recycle will be produced. Due to their high actinide content MOX residues require immobilization within a robust host matrix. Although it is possible to immobilize actinides in vitreous wasteforms; ceramic phases, such as brannerite (UTi2O6), are attractive due to their high waste loading capacity and relative insolubility. A range of uranium brannerites, formulated GdxU1-xTi2O6, were prepared using a mixed oxide route. Charge compensation of divalent and trivalent cations was expected to occur via the oxidation of U4+ to higher valence states (U5+ or U6+). Gd3+ was added to act as a neutron absorber in the final Pu bearing wasteform. X-ray powder diffraction of synthesised specimens found that phase distribution was strongly affected by processing atmosphere (air or Ar). In all cases prototypical brannerite was formed accompanied by different secondary phases dependent on processing atmosphere. Microstructural analysis (SEM) of the sintered samples confirmed the results of the X-ray powder diffraction. The preliminary results presented here indicate that brannerite is a promising host matrix for mixed oxide fuel residues
Exact solutions of Dyson-Schwinger equations for iterated one-loop integrals and propagator-coupling duality
The Hopf algebra of undecorated rooted trees has tamed the combinatorics of
perturbative contributions, to anomalous dimensions in Yukawa theory and scalar
theory, from all nestings and chainings of a primitive self-energy
subdivergence. Here we formulate the nonperturbative problems which these
resummations approximate. For Yukawa theory, at spacetime dimension , we
obtain an integrodifferential Dyson-Schwinger equation and solve it
parametrically in terms of the complementary error function. For the scalar
theory, at , the nonperturbative problem is more severe; we transform it
to a nonlinear fourth-order differential equation. After intensive use of
symbolic computation we find an algorithm that extends both perturbation series
to 500 loops in 7 minutes. Finally, we establish the propagator-coupling
duality underlying these achievements making use of the Hopf structure of
Feynman diagrams.Comment: 20p, 2 epsf fi
On the existence of AgM9(VO4)(6)I (M = Ba, Pb)
The syntheses of the reported compounds AgM9(VO4)6I (M ¼ Ba, Pb) were reinvestigated. Stoichiometric
amounts of AgI with either M3(VO4)2 (M ¼ Ba, Pb) or PbO and V2O5 were reacted in the solid-state at
elevated temperatures in air or in flame-sealed quartz vessels. The resulting products were characterized
by X-ray diffraction, scanning electron microscopy with energy dispersive X-ray analysis, and thermal
analyses. Results show that, for all reaction conditions, the target AgM9(VO4)6I (M ¼ Ba, Pb) phases could
not be isolated. Instead, heterogeneous phase distributions of primarily M3(VO4)2 (M ¼ Ba, Pb) and AgI
were obtained. These findings demonstrate that AgI incorporation into single phase, iodine-deficient
apatite derivatives for the immobilization of iodine-129 are not feasible under such conditions. This
conclusion is important for the conditioning of iodine-129 in advanced reprocessing flowsheets, where
iodine is typically sequestered as AgI
Austerity and anti-austerity : the political economy of refusal in ‘low-resistance’ models of capitalism
In contrast to much of the political economy literature, this article explores acts of refusal that obstruct attempts to impose austerity measures on advanced industrial democracies. It thereby complements a literature that has thus far focused far more upon the (apparently unobstructed) imposition of austerity. In doing so, it uses two typically ‘low-resistance’ countries – Japan and the UK –as least-likely cases and finds that austerity is rarely uncontested. Using fuzzy set Qualitative Comparative Analysis, it highlights the ‘causal recipes’ sufficient for both (1) anti-austerity activity to have a significant impact on austerity proposals and (2) the smooth (unobstructed) imposition of austerity. The politics of austerity is shown to be better understood as an iterative interaction between proposals for austerity and the acts of refusal they encounter. These obstacles to austerity appear more straightforward to activate effectively in Japan’s coordinated model of capitalism, whilst the UK’s liberal market economy tends to generate more innovative forms of dissent that (if they are sufficiently militant) provide an alternative route towards the obstruction of austerity
Synthesis of simulant ‘lava-like’ fuel containing materials (LFCM) from the Chernobyl reactor Unit 4 meltdown
A preliminary investigation of the synthesis and characterization of simulant ‘lava-like’ fuel containing materials (LFCM), as low activity analogues of LFCM produced by the melt down of Chernobyl Unit 4. Simulant materials were synthesized by melting batched reagents in a tube furnace at 1500 °C, under reducing atmosphere with controlled cooling to room temperature, to simulate conditions of lava formation. Characterization using XRD and SEM-EDX identified several crystalline phases including ZrO2, UOx and solid solutions with spherical metal particles encapsulated by a glassy matrix. The UOX and ZrO2 phase morphology was very diverse comprising of fused crystals to dendritic crystallites from the crystallization of uranium initially dissolved in the glass phase. This project aims to develop simulant LFCM to assess the durability of Chernobyl lavas and to determine the rate of dissolution, behavior and evolution of these materials under shelter conditions
Critical currents in Josephson junctions, with unconventional pairing symmetry: versus
Phenomenological Ginzburg-Landau theory is used to calculate the possible
spontaneous vortex states that may exist at corner junctions of
-wave, (where or ) and s-wave superconductors.
We study the magnetic flux and the critical current modulation with the
junction orientation angle , the magnitude of the order parameter, and
the magnetic field . It is seen that the critical current versus the
magnetic flux relation is symmetric / asymmetric for when
the orientation is exactly such that the lobes of the dominant
-wave order parameter points towards the two junctions, which are
at right angles for the corner junction. The conclusion is that a measurement
of the relation may distinguish which symmetry ( or
) the order parameter has.Comment: 11 pages with 11 figures, Changed conten
The Frail-LESS (LEss Sitting and Sarcopenia in Frail older adults) intervention to improve sarcopenia and maintain independent living via reductions in prolonged sitting: A randomised controlled feasibility trial protocol
Background
Sarcopenia is a progressive and generalised loss of muscle mass and function with advancing age and is a major contributor to frailty. These conditions lead to functional disability, loss of independence, and lower quality of life. Sedentary behaviour is adversely associated with sarcopenia and frailty. Reducing and breaking up sitting should thus be explored as an intervention target for their management. The primary aim of this study, therefore, is to examine the feasibility, safety, and acceptability of conducting a randomised controlled trial (RCT) that evaluates a remotely delivered intervention to improve sarcopenia and independent living via reducing and breaking up sitting in frail older adults.
Methods
This mixed-methods randomised controlled feasibility trial will recruit 60 community-dwelling older adults aged ≥ 65 years with very mild or mild frailty. After baseline measures, participants will be randomised to receive the Frail-LESS (LEss Sitting and Sarcopenia in Frail older adults) intervention or serve as controls (usual care) for 6 months. Frail-LESS is a remotely delivered intervention comprising of tailored feedback on sitting, information on the health risks of excess sitting, supported goal setting and action planning, a wearable device that tracks inactive time and provides alerts to move, health coaching, and peer support. Feasibility will be assessed in terms of recruitment, retention and data completion rates. A process evaluation will assess intervention acceptability, safety, and fidelity of the trial. The following measures will be taken at baseline, 3 months, and 6 months: sitting, standing, and stepping using a thigh-worn activPAL4 device, sarcopenia (via hand grip strength, muscle mass, and physical function), mood, wellbeing, and quality of life.
Discussion
This study will determine the feasibility, safety, and acceptability of evaluating a remote intervention to reduce and break up sitting to support improvements in sarcopenia and independent living in frail older adults. A future definitive RCT to determine intervention effectiveness will be informed by the study findings.
Trial registration
ISRCTN, ISRCTN17158017; Registered 6 August 2021, https://www.isrctn.com/ISRCTN17158017Abbeyfield Research Foundatio
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