41,884 research outputs found
“And it was all my choice but it didn’t feel like a choice”: a re-examination of interpretation of data using a ‘rhetoric of choice’ lens
This research aims to re-examine interpretations of data collected from second-time 2 mothers about their experiences of becoming a mother to a second child using lenses of 3 rhetoric of choice and choice feminism. The interpretations are reconsidered to identify 4 ways in which tensions between maternal status and researcher positionality have 5 influenced the ways they were reached. The paper describes two studies, each conducted 6 by one of the authors, and the interpretations of the data made at the time the research 7 was carried out. It discusses alternative interpretations and how they challenge both the 8 researcher role and theoretical explanations of gender inequity and attachment. The paper 9 concludes that feminist research can be strengthened by attending to the intersections 10 between maternal status, and positioning as feminist, woman and researche
Emergent Nesting of the Fermi Surface from Local-Moment Description of Iron-Pnictide High-Tc Superconductors
We uncover the low-energy spectrum of a t-J model for electrons on a square
lattice of spin-1 iron atoms with 3dxz and 3dyz orbital character by applying
Schwinger-boson-slave-fermion mean-field theory and by exact diagonalization of
one hole roaming over a 4 x 4 x 2 lattice. Hopping matrix elements are set to
produce hole bands centered at zero two-dimensional (2D) momentum in the
free-electron limit. Holes can propagate coherently in the t-J model below a
threshold Hund coupling when long-range antiferromagnetic order across the d+ =
3d(x+iy)z and d- = 3d(x-iy)z orbitals is established by magnetic frustration
that is off-diagonal in the orbital indices. This leads to two hole-pocket
Fermi surfaces centered at zero 2D momentum. Proximity to a commensurate
spin-density wave (cSDW) that exists above the threshold Hund coupling results
in emergent Fermi surface pockets about cSDW momenta at a quantum critical
point (QCP). This motivates the introduction of a new Gutzwiller wavefunction
for a cSDW metal state. Study of the spin-fluctuation spectrum at cSDW momenta
indicates that the dispersion of the nested band of one-particle states that
emerges is electron-type. Increasing Hund coupling past the QCP can push the
hole-pocket Fermi surfaces centered at zero 2D momentum below the Fermi energy
level, in agreement with recent determinations of the electronic structure of
mono-layer iron-selenide superconductors.Comment: 41 pages, 12 figures, published versio
Intermittency in Hall-magnetohydrodynamics with a strong guide field
We present a detailed study of intermittency in the velocity and magnetic
field fluctuations of compressible Hall-magnetohydrodynamic turbulence with an
external guide field. To solve the equations numerically, a reduced model valid
when a strong guide field is present is used. Different values for the ion skin
depth are considered in the simulations. The resulting data is analyzed
computing field increments in several directions perpendicular to the guide
field, and building structure functions and probability density functions. In
the magnetohydrodynamic limit we recover the usual results with the magnetic
field being more intermittent than the velocity field. In the presence of the
Hall effect, field fluctuations at scales smaller than the ion skin depth show
a substantial decrease in the level of intermittency, with close to monofractal
scaling.Comment: 10 pages, 8 figure
The application of a qualitative approach to adult attachment research: a short report
A qualitative pluralistic exploration of a couple relationship across the transition to second-time parenthood. This short article reports on the female partner during the pregnancy phase. It reports on her attachment history using BNIM and reports on her pregnancy phase using narrative analysis
A qualitatively driven approach to multimethod and mixed methods research
This chapter discusses the meaning of qualitatively -driven inquiry and what this is in the context of mixed and multi methods research. It distinguishes between qualitatively-driven mixed and multi methods approaches and considers why methods may be mixed using a qualitatively-driven approach. The chapter identifies some reasons for using qualitatively-driven mixed and multi method approaches and defines templates for their application. The chapter provides several research examples throughout to illustrate the insight gained with these approaches. It concludes with in-depth discussions of the value of these approaches and considers their contribution more widely to the field of mixed-methods researc
The high-pressure behavior of CaMoO4
We report a high-pressure study of tetragonal scheelite-type CaMoO4 up to 29
GPa. In order to characterize its high-pressure behavior, we have combined
Raman and optical-absorption measurements with density-functional theory
calculations. We have found evidence of a pressure-induced phase transition
near 15 GPa. Experiments and calculations agree in assigning the high-pressure
phase to a monoclinic fergusonite-type structure. The reported results are
consistent with previous powder x-ray-diffraction experiments, but are in
contradiction with the conclusions obtained from earlier Raman measurements,
which support the existence of more than one phase transition in the pressure
range covered by our studies. The observed scheelite-fergusonite transition
induces significant changes in the electronic band gap and phonon spectrum of
CaMoO4. We have determined the pressure evolution of the band gap for the low-
and high-pressure phases as well as the frequencies and pressure dependences of
the Raman-active and infrared-active modes. In addition, based upon
calculations of the phonon dispersion of the scheelite phase, carried out at a
pressure higher than the transition pressure, we propose a possible mechanism
for the reported phase transition. Furthermore, from the calculations we
determined the pressure dependence of the unit-cell parameters and atomic
positions of the different phases and their room-temperature equations of
state. These results are compared with previous experiments showing a very good
agreement. Finally, information on bond compressibility is reported and
correlated with the macroscopic compressibility of CaMoO4. The reported results
are of interest for the many technological applications of this oxide.Comment: 36 pages, 10 figures, 8 table
The Luminous Convolution Model as an alternative to dark matter in spiral galaxies
The Luminous Convolution Model (LCM) demonstrates that it is possible to
predict the rotation curves of spiral galaxies directly from estimates of the
luminous matter. We consider two frame-dependent effects on the light observed
from other galaxies: relative velocity and relative curvature. With one free
parameter, we predict the rotation curves of twenty-three (23) galaxies
represented in forty-two (42) data sets. Relative curvature effects rely upon
knowledge of both the gravitational potential from luminous mass of the
emitting galaxy and the receiving galaxy, and so each emitter galaxy is
compared to four (4) different Milky Way luminous mass models. On average in
this sample, the LCM is more successful than either dark matter or modified
gravity models in fitting the observed rotation curve data.
Implications of LCM constraints on populations synthesis modeling are
discussed in this paper. This paper substantially expands the results in
arXiv:1309.7370.Comment: Implications of LCM constraints on populations synthesis modeling are
discussed in this paper. This paper substantially expands the results in
arxiv:1309.737
Plasma deposition of constrained layer damping coatings
Plasma techniques are used to generate constrained layer damping (CLD) coatings on metallic substrates. The process involves the deposition of relatively thick, hard ceramic layers on to soft polymeric damping materials while maintaining the integrity of both layers. Reactive plasma sputter-deposition from an aluminium alloy target is used to deposit alumina layers, with Young's modulus in the range 77-220GPa and thickness up to 335 μ, on top of a silicone film. This methodology is also used to deposit a 40 μ alumina layer on a conventional viscoelastic damping film to produce an integral damping coating. Plasma CLD systems are shown to give at least 50 per cent more damping than equivalent metal-foil-based treatments. Numerical methods for rapid prediction of the performance of such coatings are discussed and validated by comparison with experimental results
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