2,072 research outputs found
The time course od retrograde transsynaptic transport of tetanus toxin fragment C in the oculomotor system of the rabbit after injection into extraocular eye muscles
Quantum to classical crossover in the 2D easy-plane XXZ model
Ground-state and thermodynamical properties of the spin-1/2 two-dimensional
easy-plane XXZ model are investigated by both a Green's-function approach and
by Lanczos diagonalizations on lattices with up to 36 sites. We calculate the
spatial and temperature dependences of various spin correlation functions, as
well as the wave-vector dependence of the spin susceptibility for all
anisotropy parameters . In the easy--plane ferromagnetic region , the longitudinal correlators of spins at distance change sign
at a finite temperature . This transition, observed in
the 2D case for the first time, can be interpreted as a quantum to classical
crossover.Comment: 4 pages, 6 figures, Contribution to the Ising Centennial Colloquium,
ICM2000, Belo Horizonte, Brazil, August 200
Moses and the Ark: exploring semantic illusions
In Part One, three experiments investigated the effects of the surface structure of semantic illusion sentences upon semantic illusion rate (Chapters 3 to 6), but only a comparison of question and statements revealed any significant effects, with questions leading to more semantic illusion responses. To explore the implications of this lack of effect, a rating scale study was designed to provide an overview of how semantic illusion sentences compare to sentences used in ordinary discourse: semantic illusion type sentences were found to differ significantly from other sentences along a number of salient dimensions.
In Part Two, three further experiments related semantic illusions to problem solving and examined the processing requirements of semantic illusions. Findings indicated that semantic illusions are subject to a kind of ‘functional fixedness’, which prevents thorough processing (Chapters 9 and 10). This may in part be explained by the load that semantic illusion sentences place on working memory, as was indicated by the results of two further experiments, which investigated the role that the different components of working memory play in semantic illusion processing (Chapter 11)
Entanglement measurement with discrete multiple coin quantum walks
Within a special multi-coin quantum walk scheme we analyze the effect of the
entanglement of the initial coin state. For states with a special entanglement
structure it is shown that this entanglement can be meausured with the mean
value of the walk, which depends on the i-concurrence of the initial coin
state. Further on the entanglement evolution is investigated and it is shown
that the symmetry of the probability distribution is reflected by the symmetry
of the entanglement distribution.Comment: 9 pages, IOP styl
Neurotransmitter profile of saccadic omnipause neurons in nucleus raphe interpositus
Saccadic omnipause neurons (OPNs) are essential for the generation of saccadic eye movements. In primates OPNs are located near the midline within the nucleus raphe interpositus (rip). In the present study we used several different neuroanatomical methods to investigate the transmitters associated with OPNs in the monkey. Immunolabeling for the calcium-binding protein parvalbumin was employed to mark OPNs in the monkey and define the homologous cell group in cat and human. The use of antibodies against GABA, glycine (GLY), glutamate (GLU), serotonin (5-HT), and tyrosine hydroxylase revealed that the somata of OPNs are GLY immunoreactive, but they are devoid of GABA and 5-HT immunostaining. In situ hybridization with the GAD67 mRNA probe confirmed the negative GABA immunostaining of OPNs. 3H-GLY was injected into a projection field of OPNs, the rostral interstitial nucleus of the medial longitudinal fascicle (riMLF)--the vertical saccadic burst neuron area. This resulted in selective retrograde labeling of the OPNs in rip, while no labeling was found in the superior colliculus, which sends an excitatory projection to the riMLF. The somata and dendrites of putative burst neurons in the riMLF were contacted by numerous GLY- immunoreactive terminals. The quantitative analysis of immunoreactive terminal-like structures contacting OPNs revealed a strong input from GLY- and GABA-positive terminals on somata and dendrites, whereas GLU- positive puncta were mainly confined to the dendrites. Very few 5-HT and catecholaminergic terminals contacted OPN somata. Our findings suggest that OPNs use GLY as a neurotransmitter, and they receive numerous contacts from GABAergic, glycinergic, and glutaminergic afferents, and significantly fewer from monoaminergic inputs.</jats:p
Stable Magnetostatic Solitons in Yttrium Iron Garnet Film Waveguides for Tilted in-Plane Magnetic Fields
The possibility of nonlinear pulses generation in Yttrium Iron Garnet thin
films for arbitrary direction between waveguide and applied static in-plane
magnetic field is considered. Up to now only the cases of in-plane magnetic
fields either perpendicular or parallel to waveguide direction have been
studied both experimentally and theoretically. In the present paper it is shown
that also for other angles (besides 0 or 90 degrees) between a waveguide and
static in-plane magnetic field the stable bright or dark (depending on
magnitude of magnetic field) solitons could be created.Comment: Phys. Rev. B (accepted, April 1, 2002
Immunohistological studies on neoplasms of female and male Onchocerca volvulus: filarial origin and absence of Wolbachia from tumor cells
Up to 5% of untreated female Onchocerca volvulus filariae develop potentially fatal pleomorphic neoplasms, whose incidence is increased following ivermectin treatment. We studied the occurrence of 8 filarial proteins and of Wolbachia endobacteria in the tumor cells. Onchocercomas from patients, untreated and treated with antibiotics and anthelminthics, were examined by immunohistology. Neoplasms were diagnosed in 112 of 3587 female and in 2 of 1570 male O. volvulus. The following proteins and other compounds of O. volvulus were expressed in the cells of the neoplasms: glutathione S-transferase 1, lysosomal aspartic protease, cAMP-dependent protein kinase, alpha-enolase, aspartate aminotransferase, ankyrin E1, tropomyosin, heat shock protein 60, transforming growth factor-beta, and prostaglandin E2. These findings prove the filarial origin of the neoplasms and confirm the pleomorphism of the tumor cells. Signs indicating malignancy of the neoplasms are described. Wolbachia were observed in the hypodermis, oocytes, and embryos of tumor-harbouring filariae using antibodies against Wolbachia surface protein, Wolbachia HtrA-type serine protease, and Wolbachia aspartate aminotransferase. In contrast, Wolbachia were not found in the cells of the neoplasms. Further, neoplasm-containing worms were not observed after more than 10 months after the start of sufficient treatment with doxycycline or doxycycline plus ivermectin
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