1,472 research outputs found
A globally accurate theory for a class of binary mixture models
Using the self-consistent Ornstein-Zernike approximation (SCOZA) results for
the 3D Ising model, we obtain phase diagrams for binary mixtures described by
decorated models. We obtain the plait point, binodals, and closed-loop
coexistence curves for the models proposed by Widom, Clark, Neece, and Wheeler.
The results are in good agreement with series expansions and experiments.Comment: 16 pages, 10 figure
Verbalisers and Visualisers: Cognitive Styles That Are Less Than Equal
Over the past thirty years numerous models of cognitive style, varying in complexity and applicability, have been developed. While these models have sparked a vast body of educational research, the results have been equivocal. The models have been widely criticized for their lack of precision and predictability. According to Kozhevnikov, Kosslyn & Sheppard (2005, p 710) “much of the previous work suffered from arbitrary distinctions and overlapping dimensions.” In spite of the criticism, several models of cognitive style survive and continue to stimulate research. Two of these models, the Field Dependent – Field Independence cognitive style and the Reflective-Impulsivity model will be reviewed briefly. Then we will discuss the Verbaliser-visualiser model on which the present research is based
Solution of an associating lattice gas model with density anomaly on a Husimi lattice
We study a model of a lattice gas with orientational degrees of freedom which
resemble the formation of hydrogen bonds between the molecules. In this model,
which is the simplified version of the Henriques-Barbosa model, no distinction
is made between donors and acceptors in the bonding arms. We solve the model in
the grand-canonical ensemble on a Husimi lattice built with hexagonal
plaquettes with a central site. The ground-state of the model, which was
originally defined on the triangular lattice, is exactly reproduced by the
solution on this Husimi lattice. In the phase diagram, one gas and two liquid
(high density-HDL and low density-LDL) phases are present. All phase
transitions (GAS-LDL, GAS-HDL, and LDL-HDL) are discontinuous, and the three
phases coexist at a triple point. A line of temperatures of maximum density
(TMD) in the isobars is found in the metastable GAS phase, as well as another
line of temperatures of minimum density (TmD) appears in the LDL phase, part of
it in the stable region and another in the metastable region of this phase.
These findings are at variance with simulational results for the same model on
the triangular lattice, which suggested a phase diagram with two critical
points. However, our results show very good quantitative agreement with the
simulations, both for the coexistence loci and the densities of particles and
of hydrogen bonds. We discuss the comparison of the simulations with our
results.Comment: 12 pages, 5 figure
How can diagnostic assessment programs be implemented to enhance inter-professional collaborative care for cancer?
BackgroundInter-professional collaborative care (ICC) for cancer leads to multiple system, organizational, professional, and patient benefits, but is limited by numerous challenges. Empirical research on interventions that promote or enable ICC is sparse so guidance on how to achieve ICC is lacking. Research shows that ICC for diagnosis could be improved. Diagnostic assessment programs (DAPs) appear to be a promising model for enabling ICC. The purpose of this study was to explore how DAP structure and function enable ICC, and whether that may be associated with organizational and clinical outcomes.MethodsA case study approach will be used to explore ICC among eight DAPs that vary by type of cancer (lung, breast), academic status, and geographic region. To describe DAP function and outcomes, and gather information that will enable costing, recommendations expressed in DAP standards and clinical guidelines will be assessed through retrospective observational study. Data will be acquired from databases maintained by participating DAPs and the provincial cancer agency, and confirmed by and supplemented with review of medical records. We will conduct a pilot study to explore the feasibility of estimating the incremental cost-effectiveness ratio using person-level data from medical records and other sources. Interviews will be conducted with health professionals, staff, and referring physicians from each DAP to learn about barriers and facilitators of ICC. Qualitative methods based on a grounded approach will be used to guide sampling, data collection and analysis.DiscussionFindings may reveal opportunities for unique structures, interventions or tools that enable ICC that could be developed, implemented, and evaluated through future research. This information will serve as a formative needs assessment to identify the nature of ongoing or required improvements, which can be directly used by our decision maker collaborators, and as a framework by policy makers, cancer system managers, and DAP managers elsewhere to strategically plan for and implement diagnostic cancer services
Self-aligned 0.12mm T-gate In.53Ga.47As/In.52Al.48As HEMT Technology Utilising a Non Annealed Ohmic Contact Strategy
An InGaAs/InAlAs based HEMT structure, lattice matched to an InP substrate, is presented in which drive current and transconductance has been optimized through a double-delta doping strategy. Together with an increase in channel carrier density, this allows the use of a non-annealed ohmic contact process. HEMT devices with 120 nm standard and self-aligned T-gates were fabricated using the non-annealed ohmic process. At DC, self-aligned and standard devices exhibited transconductances of up to 1480 and 1100 mS/mm respectively, while both demonstrated current densities in the range 800 mA/mm. At RF, a cutoff frequency f/sub T/ of 190 GHz was extracted for the self-aligned device. The DC characteristics of the standard devices were then calibrated and modelled using a compound semiconductor Monte Carlo device simulator. MC simulations provide insight into transport within the channel and illustrate benefits over a single delta doped structure
Saltation transport on Mars
We present the first calculation of saltation transport and dune formation on
Mars and compare it to real dunes. We find that the rate at which grains are
entrained into saltation on Mars is one order of magnitude higher than on
Earth. With this fundamental novel ingredient, we reproduce the size and
different shapes of Mars dunes, and give an estimate for the wind velocity on
Mars.Comment: 4 pages, 3 figure
Dune formation on the present Mars
We apply a model for sand dunes to calculate formation of dunes on Mars under
the present Martian atmospheric conditions. We find that different dune shapes
as those imaged by Mars Global Surveyor could have been formed by the action of
sand-moving winds occuring on today's Mars. Our calculations show, however,
that Martian dunes could be only formed due to the higher efficiency of Martian
winds in carrying grains into saltation. The model equations are solved to
study saltation transport under different atmospheric conditions valid for
Mars. We obtain an estimate for the wind speed and migration velocity of
barchan dunes at different places on Mars. From comparison with the shape of
bimodal sand dunes, we find an estimate for the timescale of the changes in
Martian wind regimes.Comment: 16 pages, 12 figure
Detecting genetic regions associated with height in the native ponies of the British Isles by using high density SNP genotyping
Height is an important characteristic in the equine industry, although little is known about its genetic control in native British breeds of ponies. This study aimed to map QTL data with the withers height in four pony breeds native to the British Isles, including two different sections within Welsh Cobs. In this study, a genome-wide analysis approach using the Illumina Equine SNP50 Infinium BeadChip was applied to 105 ponies and cobs. Analysis identified 222 highly significant height-associated SNPs (P < 10-5), among which three SNPs on ECA9 have also been previously reported elsewhere. The highest number of significant SNPs associated to height in the native British horses were located on ECA1, ECA8 and ECA16
Solar energy for all? Understanding the successes and shortfalls through a critical comparative assessment of Bangladesh, Brazil, India, Mozambique, Sri Lanka and South Africa
Lanterns, homes systems, hot water systems and micro-grids based on small-scale solar have become prominent ways to address the energy access challenge. As momentum grows for this form of energy transition this paper draws together research on small-scale solar in six different countries – Bangladesh, Brazil, India, Mozambique, Sri Lanka and South Africa – to argue for a need to understand how, when, and for whom solar provides energy access. It argues that an assemblage perspective can provide vital insights into the diversity and dynamism of energy access. The paper demonstrates that the diverse ways in which solar provides energy access is a function of the flexibility/fixity of the socio-technical assemblage and the de/centralisation of agency. The central thesis of this paper is that energy access is fluid and ever changing and we need fluid, easily maintainable, locally modifiable ‘assemblages’ for providing such access. Using this perspective, we find three common features of solar energy access across our case studies. First, there are significant gaps between what solar projects are designed to achieve and what they deliver, which are highly contingent on the flexibility of their structure and the decentralisation of agency within them. Second, access needs to endure continuously. Third, to foster enduring access, projects should embed logics of improvisation. This paper is based on six separate qualitative research projects conducted during 2010–2016. It draws data from 482 interviews, 91 home tours and 12 group discussions
Dynamics of Inflationary Universes with Positive Spatial Curvature
If the spatial curvature of the universe is positive, then the curvature term
will always dominate at early enough times in a slow-rolling inflationary
epoch. This enhances inflationary effects and hence puts limits on the possible
number of e-foldings that can have occurred, independently of what happened
before inflation began and in particular without regard for what may have
happened in the Planck era. We use a simple multi-stage model to examine this
limit as a function of the present density parameter and the epoch
when inflation ends.Comment: 9 Pages RevTex4. Revised and update
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