6,299 research outputs found
Neutrino Breakup of A=3 Nuclei in Supernovae
We extend the virial equation of state to include 3H and 3He nuclei, and
predict significant mass-three fractions near the neutrinosphere in supernovae.
While alpha particles are often more abundant, we demonstrate that energy
transfer cross-sections for muon and tau neutrinos at low densities are
dominated by breakup of the loosely-bound 3H and 3He nuclei. The virial
coefficients involving A=3 nuclei are calculated directly from the
corresponding nucleon-3H and nucleon-3He scattering phase shifts. For the
neutral-current inelastic cross-sections and the energy transfer cross
sections, we perform ab-initio calculations based on microscopic two- and
three-nucleon interactions and meson-exchange currents.Comment: 6 pages, 2 figures, minor additions, to appear in Phys. Rev.
An Analytic Equation of State for Ising-like Models
Using an Environmentally Friendly Renormalization we derive, from an
underlying field theory representation, a formal expression for the equation of
state, , that exhibits all desired asymptotic and analyticity
properties in the three limits , and . The only
necessary inputs are the Wilson functions , and
, associated with a renormalization of the transverse vertex
functions. These Wilson functions exhibit a crossover between the Wilson-Fisher
fixed point and the fixed point that controls the coexistence curve.
Restricting to the case N=1, we derive a one-loop equation of state for naturally parameterized by a ratio of non-linear scaling fields. For
we show that a non-parameterized analytic form can be deduced. Various
asymptotic amplitudes are calculated directly from the equation of state in all
three asymptotic limits of interest and comparison made with known results. By
positing a scaling form for the equation of state inspired by the one-loop
result, but adjusted to fit the known values of the critical exponents, we
obtain better agreement with known asymptotic amplitudes.Comment: 10 pages, 2 figure
Mining whole sample mass spectrometry proteomics data for biomarkers: an overview
In this paper we aim to provide a concise overview of designing and conducting an MS proteomics experiment in such a way as to allow statistical analysis that may lead to the discovery of novel biomarkers. We provide a summary of the various stages that make up such an experiment, highlighting the need for experimental goals to be decided upon in advance. We discuss issues in experimental design at the sample collection stage, and good practise for standardising protocols within the proteomics laboratory. We then describe approaches to the data mining stage of the experiment, including the processing steps that transform a raw mass spectrum into a useable form. We propose a permutation-based procedure for determining the significance of reported error rates. Finally, because of its general advantages in speed and cost, we suggest that MS proteomics may be a good candidate for an early primary screening approach to disease diagnosis, identifying areas of risk and making referrals for more specific tests without necessarily making a diagnosis in its own right. Our discussion is illustrated with examples drawn from experiments on bovine blood serum conducted in the Centre for Proteomic Research (CPR) at Southampton University
Topological Phase Transitions and Holonomies in the Dimer Model
We demonstrate that the classical dimer model defined on a toroidal hexagonal
lattice acquires holonomy phases in the thermodynamic limit. When all
activities are equal the lattice sizes must be considered mod 6 in which case
the finite size corrections to the bulk partition function correspond to a
massless Dirac Fermion in the presence of a flat connection with nontrivial
holonomy. For general bond activities we find that the phase transition in this
model is a topological one, where the torus degenerates and its modular
parameter becomes real at the critical temperature. We argue that these
features are generic to bipartite dimer models and we present a more general
lattice whose continuum partition function is that of a massive Dirac Fermion.Comment: 7 pages, 4 figures. Minor corrections with additional figure
Dallas with balls: televized sport, soap opera and male and female pleasures
Two of the most popular of television genres, soap opera and sports coverage have been very much differentiated along gender lines in terms of their audiences. Soap opera has been regarded very much as a 'gynocentric' genre with a large female viewing audience while the audiences for television sport have been predominantly male. Gender differentiation between the genres has had implications for the popular image of each. Soap opera has been perceived as inferior; as mere fantasy and escapism for women while television sports has been perceived as a legitimate, even edifying experience for men.
In this article the authors challenge the view that soap opera and television sport are radically different and argue that they are, in fact, very similar in a number of significant ways. They suggest that both genres invoke similar structures of feeling and sensibility in their respective audiences and that television sport is a 'male soap opera'. They consider the ways in which the viewing context of each genre is related to domestic life and leisure, the ways in which the textual structure and conventions of each genre invoke emotional identification, and finally, the ways in which both genres re-affirm gender identities
Creative councils for creative communities: The Marrickville creativity project
Report based on a teaching and research collaboration between UTS and Marrickville Council NS
Modular Invariance of Finite Size Corrections and a Vortex Critical Phase
We analyze a continuous spin Gaussian model on a toroidal triangular lattice
with periods and where the spins carry a representation of the
fundamental group of the torus labeled by phases and . We find the
{\it exact finite size and lattice corrections}, to the partition function ,
for arbitrary mass and phases . Summing over phases gives
the corresponding result for the Ising model. The limits and
do not commute. With the model exhibits a {\it vortex
critical phase} when at least one of the is non-zero. In the continuum or
scaling limit, for arbitrary , the finite size corrections to are
{\it modular invariant} and for the critical phase are given by elliptic theta
functions. In the cylinder limit the ``cylinder charge''
is a non-monotonic function of that ranges from
for to zero for .Comment: 12 pages of Plain TeX with two postscript figure insertions called
torusfg1.ps and torusfg2.ps which can be obtained upon request from
[email protected]
A New Method for the High-Precision Assessment of Tumor Changes in Response to Treatment
Imaging demonstrates that preclinical and human tumors are heterogeneous,
i.e. a single tumor can exhibit multiple regions that behave differently during
both normal development and also in response to treatment. The large variations
observed in control group tumors can obscure detection of significant
therapeutic effects due to the ambiguity in attributing causes of change. This
can hinder development of effective therapies due to limitations in
experimental design, rather than due to therapeutic failure. An improved method
to model biological variation and heterogeneity in imaging signals is
described. Specifically, Linear Poisson modelling (LPM) evaluates changes in
apparent diffusion co-efficient (ADC) before and 72 hours after radiotherapy,
in two xenograft models of colorectal cancer. The statistical significance of
measured changes are compared to those attainable using a conventional t-test
analysis on basic ADC distribution parameters. When LPMs were applied to
treated tumors, the LPMs detected highly significant changes. The analyses were
significant for all tumors, equating to a gain in power of 4 fold (i.e.
equivelent to having a sample size 16 times larger), compared with the
conventional approach. In contrast, highly significant changes are only
detected at a cohort level using t-tests, restricting their potential use
within personalised medicine and increasing the number of animals required
during testing. Furthermore, LPM enabled the relative volumes of responding and
non-responding tissue to be estimated for each xenograft model. Leave-one-out
analysis of the treated xenografts provided quality control and identified
potential outliers, raising confidence in LPM data at clinically relevant
sample sizes
Relaxation and Localization in Interacting Quantum Maps
We quantise and study several versions of finite multibaker maps. Classically
these are exactly solvable K-systems with known exponential decay to global
equilibrium. This is an attempt to construct simple models of relaxation in
quantum systems. The effect of symmetries and localization on quantum transport
is discussed.Comment: 32 pages. LaTex file. 9 figures, not included. For figures send mail
to first author at '[email protected]
Effects of climate-induced changes in isoprene emissions after the eruption of Mount Pinatubo
In the 1990s the rates of increase of greenhouse gas concentrations, most notably of methane, were observed to change, for reasons that have yet to be fully determined. This period included the eruption of Mt. Pinatubo and an El Nino warm event, both of which affect biogeochemical processes, by changes in temperature, precipitation and radiation. We examine the impact of these changes in climate on global isoprene emissions and the effect these climate dependent emissions have on the hydroxy radical, OH, the dominant sink for methane. We model a reduction of isoprene emissions in the early 1990s, with a maximum decrease of 40 Tg(C)/yr in late 1992 and early 1993, a change of 9%. This reduction is caused by the cooler, drier conditions following the eruption of Mt. Pinatubo. Isoprene emissions are reduced both directly, by changes in temperature and a soil moisture dependent suppression factor, and indirectly, through reductions in the total biomass. The reduction in isoprene emissions causes increases of tropospheric OH which lead to an increased sink for methane of up to 5 Tg(CH4)/year, comparable to estimated source changes over the time period studied. There remain many uncertainties in the emission and oxidation of isoprene which may affect the exact size of this effect, but its magnitude is large enough that it should remain important
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