266 research outputs found
Construction of Simulation Wavefunctions for Aqueous Species: D3O+
This paper investigates Monte Carlo techniques for construction of compact
wavefunctions for the internal atomic motion of the D3O+ ion. The polarization
force field models of Stillinger, et al and of Ojamae, et al. were used.
Initial pair product wavefunctions were obtained from the asymptotic high
temperature many-body density matrix after contraction to atom pairs using
Metropolis Monte Carlo. Subsequent characterization shows these pair product
wavefunctions to be well optimized for atom pair correlations despite that fact
that the predicted zero point energies are too high. The pair product
wavefunctions are suitable to use within variational Monte Carlo, including
excited states, and density matrix Monte Carlo calculations. Together with the
pair product wavefunctions, the traditional variational theorem permits
identification of wavefunction features with significant potential for further
optimization. The most important explicit correlation variable found for the
D3O+ ion was the vector triple product {\bf r}({\bf
r}{\bf r}). Variational Monte Carlo with 9 of such
explicitly correlated functions yielded a ground state wavefunction with an
error of 5-6% in the zero point energy.Comment: 17 pages including 6 figures, typos correcte
Inflammation of peripheral tissues and injury to peripheral nerves induce diferring effects in the expression of the calcium-sensitive anandamide synthesising enzyme and related molecules in rat primary sensory neuron
Elevation of intracellular Ca 2+ concentration induces the synthesis of N0 arachydonoylethanolamine (anandamide) in a sub0popu lation of primary sensory neurons. N0acylphosphatidylethanolamine phospholipa se D (NAPE0PLD) is the only known enzyme, which synthesises anandamide in a Ca 2+ 0dependent manner. NAPE0 PLD mRNA, as well as anandamide's main targets, the excitatory transient receptor potential vanilloid type 1 ion channel (TRPV1) and the inhibitory cannabinoid type 1 (CB1) receptor and the main anandamide0hydrolysing enzyme fatty acid amide hydrolase (FAAH) are all expressed by sub0populatio ns of nociceptive primary sensory neurons. Thus, NAPE0PLD, TRPV1, the CB1 rec eptor and FAAH could form an autocrine signalling system, which could shape t he activity of a major sub0 population of nociceptive primary sensory neurons, hence contribute to the development of pain. While the expression patterns of TRPV1, the CB1 receptor and FAAH have been comprehensively elucidated, little i s known about NAPE0PLD expression in primary sensory neurons under physiol ogical and pathological conditions. We report that NAPE0PLD is expressed by about a third of primary sensory neurons, the overwhelming majority of which also express nociceptive markers as well as the CB1 receptor, TRPV1 and FAAH . Inflammation of peripheral tissues and injury to peripheral nerves induce diff ering but concerted changes in the expression pattern of NAPE0PLD, the CB1 receptor, T RPV1 and FAAH. Together these data indicate the existence of the anatomical basis for an autocrine signalling system, in a major proportion of nociceptive primar y sensory neurons, and that alterations in that autocrine signalling by periphe ral pathologies could contribute to the development of both inflammatory and neuropathi c pain
Lambda and Antilambda polarization from deep inelastic muon scattering
We report results of the first measurements of Lambda and Antilambda
polarization produced in deep inelastic polarized muon scattering on the
nucleon. The results are consistent with an expected trend towards positive
polarization with increasing x_F. The polarizations of Lambda and Antilambda
appear to have opposite signs. A large negative polarization for Lambda at low
positive x_F is observed and is not explained by existing models.A possible
interpretation is presented.Comment: 9 pages, 2 figure
Shadowing in Inelastic Scattering of Muons on Carbon, Calcium and Lead at Low XBj
Nuclear shadowing is observed in the per-nucleon cross-sections of positive
muons on carbon, calcium and lead as compared to deuterium. The data were taken
by Fermilab experiment E665 using inelastically scattered muons of mean
incident momentum 470 GeV/c. Cross-section ratios are presented in the
kinematic region 0.0001 < XBj <0.56 and 0.1 < Q**2 < 80 GeVc. The data are
consistent with no significant nu or Q**2 dependence at fixed XBj. As XBj
decreases, the size of the shadowing effect, as well as its A dependence, are
found to approach the corresponding measurements in photoproduction.Comment: 22 pages, incl. 6 figures, to be published in Z. Phys.
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