Relatively Congruence-free Regular Semigroups

Yu, Wang, Wu and Ye call a semigroup S τ -congruence-free, where τ is an equivalence relation on S, if any congruence ρ on S is either disjoint from τ or contains τ . A congruence-free semigroup is then just an ω-congruence-free semigroup, where ω is the universal relation. They determined the completely regular semigroups that are τ -congruence-free with respect to each of the Green’s relations. The goal of this paper is to extend their results to all regular semigroups. Such a semigroup is J –congruence-free if and only if it is either a semilattice or has a single nontrivial J -class, J, say, and either J is a subsemigroup, in which case it is congruence-free, or otherwise its principal factor is congruence-free. Given the current knowledge of congruence-free regular semigroups, this result is probably best possible. When specialized to completely semisimple semigroups, however, a complete answer is obtained, one that specializes to that of Yu et al. A similar outcome is obtained for L and R. In the case of H, only the completely semisimple case is fully resolved, again specializing to those of Yu et al

Remarks on the number of tubulin dimers per neuron and implications for Hameroff-Penrose Orch OR

Stuart Hameroff has wrongly estimated that a typical brain neuron has 10^7^ tubulin dimers and wrongly attributed this result to Yu and Baas, J. Neurosci. 1994; 14: 2818-2829. In this letter we show that Hameroff’s estimate is based on misunderstanding of the results provided by Yu and Baas, who actually measured the total microtubule length in a single axonal projection with length of 56 μm in a differentiating in vitro stage 3 embryonic hippocampal neuron. In order to visualize how big Hameroff’s error is, we have reconstructed two of the studied by Yu and Baas embryonic hippocampal neurons with Neuromantic v1.6.3 and compared them with previously published reconstructions of adult hippocampal neurons. Correct calculations show that an adult differentiated pyramidal neuron in vivo has approximately 1.3×10^9^ tubulin dimers incorporated in cytoskeletal microtubules. This estimate has profound implications for the Hameroff-Penrose Orch OR model, because it sets limitations on the number of quantum coherent neurons and implies that if 100% of the neuronal microtubules are quantum coherent for 25 ms then Hameroff-Penrose Orch OR conscious events should involve only 15 pyramidal neurons

Erratum: First-principles study on the intrinsic stability of the magic Fe13O8 Cluster [Phys. Rev. B 61, 5781 (2000)]

See Also: Original Article: Q. Sun, Q. Wang, K. Parlinski, J. Z. Yu, Y. Hashi, X. G. Gong, and Y. Kawazoe, First-principles studies on the intrinsic stability of the magic Fe13O8 cluster, Phys. Rev. B 61, 5781 (2000)

Bilateral Hipoglossal Nerve Palsy In Necrotizing Otitis Externa

[No abstract available]734576Benecke Jr., J.A., Management of osteomyelitis of the skull base (1989) Laryngoscope, 99 (12), pp. 1220-1223Boringa, J.B., Hoekstra, O.S., Roos, J.W., Bertelsmann, F.W., Multiple cranial nerve palsy after otitis externa: A case report (1995) Clin Neurol Neurosurg, 97, pp. 332-335Rubin, J., Yu, V.L., Malignant external otitis: Insights into pathogenesis, clinical manifestations and therapy (1998) Am J Med, 85, pp. 391-39

Rabi oscillations and macroscopic quantum superposition states

A two-level atom interacting with a single radiation mode is considered, without the rotating-wave approximation, in the strong coupling regime. It is shown that, in agreement with the recent results on Rabi oscillations in a Josephson junction (Y. Nakamura, Yu. A. Pashkin and J. S. Tsai, Phys. Rev. Lett. {\bf 87}, 246601 (2001)), the Rabi frequency is indeed proportional to first kind integer order Bessel functions in the limit of a large number of photons and the dressed states are macroscopic quantum superposition states. To approach this problem analytically use is made of the dual Dyson series and the rotating-wave approximation.Comment: 7 pages, revtex, no figures. I have to thank Kazuyuki Fujii for pointing me out some corrections to introduce into the paper. Besides, the title and the nomenclature has been changed in agreement to editorial requirements. Finally, the correct citation for the paper by Nakamura et al. has been introduce