27 research outputs found
Observations of foetal heart veins draining directly into the left and right atria
Evaluation of semiserial sections of 14 normal hearts from human foetuses of gestational age 25â33 weeks showed that all of these hearts contained thin veins draining directly into the atria (maximum, 10 veins per heart). Of the 75 veins in these 14 hearts, 55 emptied into the right atrium and 20 into the left atrium. These veins were not accompanied by nerves, in contrast to tributaries of the great cardiac vein, and were negative for both smooth muscle actin (SMA) and CD34. However, the epithelium and venous wall of the anterior cardiac vein, the thickest of the direct draining veins, were strongly positive for SMA and CD34, respectively. In general, developing fibres in the vascular wall were positive for CD34, while the endothelium of the arteries and veins was strongly positive for the present DAKO antibody of SMA. The small cardiac vein, a thin but permanent tributary of the terminal portion of the great cardiac vein, was also positive for SMA and CD34. A few S100 protein-positive nerves were observed along both the anterior and small cardiac veins, but no nerves accompanied the direct dra- inage veins. These findings suggested that the latter did not develop from the early epicardiac vascular plexus but from a gulfing of the intratrabecular space or sinus of the atria. However, the immunoreactivity of the anterior cardiac vein suggests that it originated from the vascular plexus, similar to tributaries of the great cardiac vein.
Multiplicity Distributions in Canonical and Microcanonical Statistical Ensembles
The aim of this paper is to introduce a new technique for calculation of
observables, in particular multiplicity distributions, in various statistical
ensembles at finite volume. The method is based on Fourier analysis of the
grand canonical partition function. Taylor expansion of the generating function
is used to separate contributions to the partition function in their power in
volume. We employ Laplace's asymptotic expansion to show that any equilibrium
distribution of multiplicity, charge, energy, etc. tends to a multivariate
normal distribution in the thermodynamic limit. Gram-Charlier expansion allows
additionally for calculation of finite volume corrections. Analytical formulas
are presented for inclusion of resonance decay and finite acceptance effects
directly into the system partition function. This paper consolidates and
extends previously published results of current investigation into properties
of statistical ensembles.Comment: 53 pages, 7 figure
Plane-wave impulse approximation extraction of the neutron magnetic form factor from quasielastic 3He(e,eâČ) at Q2=0.3 to 0.6 (GeV/c)2
A high precision measurement of the transverse spin-dependent asymmetry ATâČ in 3He(e,eâČ) quasielastic scattering was performed in Hall A at Jefferson Lab at values of the squared four-momentum transfer, Q2, between 0.1 and 0.6 (GeV/c)2. ATâČ is sensitive to the neutron magnetic form factor, GMn. Values of GMn at Q2=0.1 and 0.2 (GeV/c)2, extracted using Faddeev calculations, were reported previously. Here, we report the extraction of GMn for the remaining Q2 values in the range from 0.3 to 0.6 (GeV/c)2 using a plane-wave impulse approximation calculation. The results are in good agreement with recent precision data from experiments using a deuterium target
Plane-wave impulse approximation extraction of the neutron magnetic form factor from quasielastic 3He(e,eâČ) at Q2=0.3 to 0.6 (GeV/c)2
A high precision measurement of the transverse spin-dependent asymmetry ATâČ in 3He(e,eâČ) quasielastic scattering was performed in Hall A at Jefferson Lab at values of the squared four-momentum transfer, Q2, between 0.1 and 0.6 (GeV/c)2. ATâČ is sensitive to the neutron magnetic form factor, GMn. Values of GMn at Q2=0.1 and 0.2 (GeV/c)2, extracted using Faddeev calculations, were reported previously. Here, we report the extraction of GMn for the remaining Q2 values in the range from 0.3 to 0.6 (GeV/c)2 using a plane-wave impulse approximation calculation. The results are in good agreement with recent precision data from experiments using a deuterium target
Extraction of the Neutron Magnetic Form Factor from Quasi-Elastic 3He(pol)(e(pol),e') at Q^2 = 0.1 - 0.6 (GeV/c)^2
We have measured the spin-dependent transverse asymmetry, A_T', in
quasi-elastic inclusive electron scattering from polarized 3He with high
precision at Q^2 = 0.1 to 0.6 (GeV/c)^2. The neutron magnetic form factor, GMn,
was extracted at Q^2 = 0.1 and 0.2 (GeV/c)^2 using a non-relativistic Faddeev
calculation that includes both final-state interactions (FSI) and
meson-exchange currents (MEC). In addition, GMn was extracted at Q^2 = 0.3 to
0.6 (GeV/c)^2 using a Plane Wave Impulse Approximation calculation. The
accuracy of the modeling of FSI and MEC effects was tested and confirmed with a
precision measurement of the spin-dependent asymmetry in the breakup threshold
region of the 3He(pol)(e(pol),e') reaction. The total relative uncertainty of
the extracted GMn data is approximately 3%. Close agreement was found with
other recent high-precision GMn data in this Q^2 range.Comment: Archival paper, 17 pages, 10 figures, 5 tables, submitted to Physical
Review C. v2: shortened considerably, updated comparison to theor
Silurian sedimentation in the South Qilian Belt: arcâcontinent collisionârelated deposition in the NE Tibet Plateau?
The South Qilian belt mainly comprises an early Paleozoic arcâophiolite complex, accretionary prism, microâcontinental block, and foreland basin. These elements represent accretionâcollision during Cambrian to Silurian time in response to closure of the ProtoâTethyan Ocean in the NE of the presentâday Tibet Plateau. Closure of the ProtoâTethyan Ocean between the Central Qilian block and the Oulongbuluke block and the associated collision took place from NE to SW in a zipperâlike style. Sediment would have been dispersed longitudinally SWâward with a progressive facies migration from marginal alluvial sediments toward slope deepâwater and deepâsea turbidites. This migration path indicates an ocean basin that shrank toward the SW. The Balonggonggaâer Formation in the western South Qilian belt represents the fill of a latest OrdovicianâSilurian remnant ocean basin that separated the Oulongbuluke block from the Central Qilian block, and records Silurian closure of the ProtoâTethyan Ocean and subduction beneath the Central Qilian block. However, alluvial deposits in the Lajishan area were accumulated in a retroâforeland basin, indicating that continentâcontinent collision in the eastern South Qilian belt occurred at c. 450â440 Ma. These results demonstrate that the ProtoâTethyan Ocean closed diachronously during early Paleozoic time