4,485 research outputs found
Kertesz on Fat Graphs?
The identification of phase transition points, beta_c, with the percolation
thresholds of suitably defined clusters of spins has proved immensely fruitful
in many areas of statistical mechanics. Some time ago Kertesz suggested that
such percolation thresholds for models defined in field might also have
measurable physical consequences for regions of the phase diagram below beta_c,
giving rise to a ``Kertesz line'' running between beta_c and the bond
percolation threshold, beta_p, in the M, beta plane.
Although no thermodynamic singularities were associated with this line it
could still be divined by looking for a change in the behaviour of high-field
series for quantities such as the free energy or magnetisation. Adler and
Stauffer did precisely this with some pre-existing series for the regular
square lattice and simple cubic lattice Ising models and did, indeed, find
evidence for such a change in high-field series around beta_p. Since there is a
general dearth of high-field series there has been no other work along these
lines.
In this paper we use the solution of the Ising model in field on planar
random graphs by Boulatov and Kazakov to carry out a similar exercise for the
Ising model on random graphs (i.e. coupled to 2D quantum gravity). We generate
a high-field series for the Ising model on random graphs and examine
its behaviour for evidence of a Kertesz line
Enhancing Care Transitions for Older People through Interprofessional Simulation: A Mixed Method Evaluation
Introduction: The educational needs of the health and social care workforce for delivering effective integrated care are important. This paper reports on the development, pilot and evaluation of an interprofessional simulation course, which aimed to support integrated care models for care transitions for older people from hospital to home.
Theory and methods:
The course development was informed by a literature review and a scoping exercise with the health and social care workforce. The course ran six times and was attended by health and social care professionals from hospital and community (n=49). The evaluation aimed to elicit staff perceptions of their learning about care transfers of older people and to explore application of learning into practice and perceived outcomes. The study used a sequential mixed method design with questionnaires completed pre (n=44) and post (n=47) course and interviews (n=9) 2-5 months later.
Results:Participants evaluated interprofessional simulation as a successful strategy. Post-course, participants identified learning points and at the interviews, similar themes with examples of application in practice were: Understanding individual needs and empathy; Communicating with patients and families; Interprofessional working; Working across settings to achieve effective care transitions.
Conclusions and discussion:An interprofessional simulation course successfully brought together health and social care professionals across settings to develop integrated care skills and improve care transitions for older people with complex needs from hospital to home
Thermoanalysis of ablation materials
Thermal analysis on pyrolysis of charring ablator material
Space environmental effects on graphite-epoxy compressive properties and epoxy tensile properties
This study characterizes the effects of electron radiation and temperature on a graphite-epoxy composite material. Compressive properties of the T300/934 material system were obtained at -250 F (-157 C), room temperature, and 250 F (121 C). Tensile specimens of the Fiberite 934 epoxy resin were fabricated and tested at room temperature and 250 F (121 C). Testing was conducted in the baseline (nonirradiated) and irradiated conditions. The radiation exposure was designed to simulate 30 year, worst-case exposure in geosynchronous Earth orbit. Mechanical properties tended to degrade at elevated temperature and improve at cryogenic temperature. Irradiation generally degraded properties at all temperatures
Carbamazepine on a carbamazepine monolayer forms unique 1D supramolecular assemblies
High-resolution STM imaging of the structures formed by carbamazepine molecules adsorbed onto a pseudo-ordered carbamazepine monolayer on Au(111) shows the formation of previously unreported 1-dimensional supramolecular assemblies
Origin of the Near-Ecliptic Circumsolar Dust Band
The zodiacal dust bands are bright infrared (IR) strips produced by thermal emission from circumsolar rings of particles. Two of the three principal dust bands, known as β and γ, were previously linked to the recent asteroid collisions that produced groups of fragments, so-called asteroid families, near the orbits of (832) Karin and (490) Veritas. The origin of the third, near-ecliptic α band has been unknown until now. Here we report the discovery of a recent breakup of a >20 km diameter asteroid near α's originally suspected source location in the Themis family. Numerical modeling and observations of the α-band thermal emission from the Spitzer Space Telescope indicate that the discovered breakup is the source of α-band particles. The recent formation of all principal dust bands implies a significant time variability of the circumstellar debris disks
Complex-Temperature Singularities in the Ising Model. III. Honeycomb Lattice
We study complex-temperature properties of the uniform and staggered
susceptibilities and of the Ising model on the honeycomb
lattice. From an analysis of low-temperature series expansions, we find
evidence that and both have divergent singularities at the
point (where ), with exponents
. The critical amplitudes at this
singularity are calculated. Using exact results, we extract the behaviour of
the magnetisation and specific heat at complex-temperature
singularities. We find that, in addition to its zero at the physical critical
point, diverges at with exponent , vanishes
continuously at with exponent , and vanishes
discontinuously elsewhere along the boundary of the complex-temperature
ferromagnetic phase. diverges at with exponent
and at (where ) with exponent , and
diverges logarithmically at . We find that the exponent relation
is violated at ; the right-hand side is 4
rather than 2. The connections of these results with complex-temperature
properties of the Ising model on the triangular lattice are discussed.Comment: 22 pages, latex, figures appended after the end of the text as a
compressed, uuencoded postscript fil
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Simulation and Measurement of Transient Fluid Phenomena within Diesel Injection
Rail pressures of modern diesel fuel injection systems have increased significantly over recent years, greatly improving atomisation of the main fuel injection event and air utilisation of the combustion process. Continued improvement in controlling the process of introducing fuel into the cylinder has led to focussing on fluid phenomena related to transient response. High-speed microscopy has been employed to visualise the detailed fluid dynamics around the near nozzle region of an automotive diesel fuel injector, during the opening, closing and post injection events. Complementary computational fluid dynamic (CFD) simulations have been undertaken to elucidate the interaction of the liquid and gas phases during these highly transient events, including an assessment of close-coupled injections. Microscopic imaging shows the development of a plug flow in the initial stages of injection, with rapid transition into a primary breakup regime, transitioning to a finely atomised spray and subsequent vaporisation of the fuel. During closuring of the injector the spray collapses, with evidence of swirling breakup structures together with unstable ligaments of fuel breaking into large slow-moving droplets. This leads to sub-optimal combustion in the developing flame fronts established by the earlier, more fully-developed spray. The simulation results predict these observed phenomena, including injector surface wetting as a result of large slow-moving droplets and post-injection discharge of liquid fuel. This work suggests that post-injection discharges of fuel play a part in the mechanism of the initial formation, and subsequent accumulation of deposits on the exterior surface of the injector. For multiple injections, opening events are influenced by the dynamics of the previous injection closure; these phenomena have been investigated within the simulations
Novel immune-modulator identified by a rapid, functional screen of the parapoxvirus ovis (Orf virus) genome
<p>Abstract</p> <p>Background</p> <p>The success of new sequencing technologies and informatic methods for identifying genes has made establishing gene product function a critical rate limiting step in progressing the molecular sciences. We present a method to functionally mine genomes for useful activities <it>in vivo</it>, using an unusual property of a member of the poxvirus family to demonstrate this screening approach.</p> <p>Results</p> <p>The genome of <it>Parapoxvirus ovis </it>(<it>Orf virus</it>) was sequenced, annotated, and then used to PCR-amplify its open-reading-frames. Employing a cloning-independent protocol, a viral expression-library was rapidly built and arrayed into sub-library pools. These were directly delivered into mice as expressible cassettes and assayed for an immune-modulating activity associated with parapoxvirus infection. The product of the B2L gene, a homolog of vaccinia F13L, was identified as the factor eliciting immune cell accumulation at sites of skin inoculation. Administration of purified B2 protein also elicited immune cell accumulation activity, and additionally was found to serve as an adjuvant for antigen-specific responses. Co-delivery of the B2L gene with an influenza gene-vaccine significantly improved protection in mice. Furthermore, delivery of the B2L expression construct, without antigen, non-specifically reduced tumor growth in murine models of cancer.</p> <p>Conclusion</p> <p>A streamlined, functional approach to genome-wide screening of a biological activity <it>in vivo </it>is presented. Its application to screening in mice for an immune activity elicited by the pathogen genome of <it>Parapoxvirus ovis </it>yielded a novel immunomodulator. In this inverted discovery method, it was possible to identify the adjuvant responsible for a function of interest prior to a mechanistic study of the adjuvant. The non-specific immune activity of this modulator, B2, is similar to that associated with administration of inactivated particles to a host or to a live viral infection. Administration of B2 may provide the opportunity to significantly impact host immunity while being itself only weakly recognized. The functional genomics method used to pinpoint B2 within an ORFeome may be more broadly applicable to screening for other biological activities in an animal.</p
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