502 research outputs found
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An analysis and evaluation of the Wechsler-Bellevue patterns of alcoholics with auditory and visual hallucinations with an attempt to discover any discriminable diagnostic pattern.
Effective Scalar Field Theory for the Electroweak Phase Transition
We investigate an effective model for the finite temperature restoration
phase transition of the electroweak theory. It is obtained by dimensional
reduction of the dimensional full theory and by subsequent integration
over all static gauge degrees of freedom. The resulting theory corresponds to a
-dimensional ferromagnet containing cubic and quartic terms of the
field in its potential function. Possible nonperturbative effects of a magnetic
screening mass are parametrically included in the potential. We analyse the
theory using mean field and numerical Monte Carlo (MC) simulation methods. At
the value of the physical Higgs mass, , considered in the
present investigation, we find a discontinuous symmetry restoring phase
transition. We determine the critical temperature, order parameter jump,
interface tension and latent heat characteristics of the transition. The Monte
Carlo results indicate a somewhat weaker first order phase transition as
compared to the mean field treatment, demonstrating that non-perturbative
fluctuations of the Higgs field are relevant. This effect is especially
important for the interface tension. Any observation of hard first order
transition could result only from non-perturbative effects related to the gauge
degrees of freedom.Comment: 28 pages and 18 figure
Interface Tension of the Electroweak Phase Transition
In our nonperturbative lattice investigation we study the interface tension
of the finite-temperature electroweak phase transition. In this analysis the
Higgs mass has been chosen to be about GeV. At the transition point of a
finite volume system, tunnelling between the symmetric and the Higgs phase
takes place. This phenomenon leads to a splitting of the ground state, which
can be used to determine the interface tension. The result obtained this way
agrees with the result of the two-coupling method and with the prediction of
the perturbative approach.Comment: 10 pages, five figures in uuencoded PS format, Latex + epsf.st
Transition temperature of a dilute homogeneous imperfect Bose gas
The leading-order effect of interactions on a homogeneous Bose gas is
theoretically predicted to shift the critical temperature by an amount
\Delta\Tc = # a_{scatt} n^{1/3} T_0 from the ideal gas result T_0, where
a_{scatt} is the scattering length and n is the density. There have been
several different theoretical estimates for the numerical coefficient #. We
claim to settle the issue by measuring the numerical coefficient in a lattice
simulation of O(2) phi^4 field theory in three dimensions---an effective theory
which, as observed previously in the literature, can be systematically matched
to the dilute Bose gas problem to reproduce non-universal quantities such as
the critical temperature. We find # = 1.32 +- 0.02.Comment: 4 pages, submitted to Phys. Rev. Lett; minor changes due to
improvement of analysis in the longer companion pape
Finite T Electroweak Phase Transition on the Lattice
This talk reviews recent lattice results on the high electroweak phase
transition. A remarkably accurate picture emerges: a) the transition is of
first order for m_H \lsim 80GeV and vanishes for larger ; b) transition
temperature, latent heat and interface tension are known, as well as c) the
properties of the broken and symmetric phases. New developments in the
sphaleron rate calculations are discussed.Comment: Talk presented at LATTICE96(electroweak), 13 pages latex, 11
eps-figure
Establishing Telepathology in Africa: Lessons From Botswana
Few reports of telepathology in Africa exist in the medical literature. With the strong need for improvement in health care infrastructure and personnel training in many African nations, telepathology provides a rapid and versatile tool to improve clinical care and foster educational and research opportunities. We describe the challenges faced in establishing robotic telepathology (RT) services at a government referral center in Botswana and reflect on conditions under which such initiatives may be most likely to succeed in sub-Saharan Africa and other parts of the developing world
Generation of human induced pluripotent stem cells using non-synthetic mRNA
Here we describe some of the crucial steps to generate induced pluripotent stemcells (iPSCs) usingmRNA transfection. Our approach uses a V. virus-derived capping enzyme instead of a cap-analog, ensuring 100% proper cap orientation for in vitro transcribedmRNA. V. virus\'' 2′-O-Methyltransferase enzymecreates a cap1 structure found in higher eukaryotes and has higher translation efficiency compared to other methods. Use of the polymeric transfection reagent polyethylenimine proved superior to other transfection methods. The mRNA created via this method did not trigger an intracellular immune response via human IFN-gamma (hIFN-γ) or alpha (hIFN-α) release, thus circumventing the use of suppressors. Resulting mRNA and protein
were expressed at high levels for over 48 h, thus obviating daily transfections. Using this method, we demonstrated swift activation of pluripotency associated genes in human fibroblasts. Low oxygen conditions further facilitated colony formation. Differentiation into different germ layers was confirmed via teratoma assay. Reprogramming with non-synthetic mRNA holds great promise for safe generation of iPSCs of human origin. Using the protocols described herein we hope to make this method more accessible to other groups as a fast, inexpensive, and non-viral reprogramming approach
Electroweak Bubble Nucleation, Nonperturbatively
We present a lattice method to compute bubble nucleation rates at radiatively
induced first order phase transitions, in high temperature, weakly coupled
field theories, nonperturbatively. A generalization of Langer's approach, it
makes no recourse to saddle point expansions and includes completely the
dynamical prefactor. We test the technique by applying it to the electroweak
phase transition in the minimal standard model, at an unphysically small Higgs
mass which gives a reasonably strong phase transition (lambda/g^2 =0.036, which
corresponds to m(Higgs)/m(W) = 0.54 at tree level but does not correspond to a
positive physical Higgs mass when radiative effects of the top quark are
included), and compare the results to older perturbative and other estimates.
While two loop perturbation theory slightly under-estimates the strength of the
transition measured by the latent heat, it over-estimates the amount of
supercooling by a factor of 2.Comment: 48 pages, including 16 figures. Minor revisions and typo fixes,
nothing substantial, conclusions essentially unchange
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