Note on Backlund transformations

The method of obtaining Backlund transformations proposed by Chern and Tenenblat (1986) fits completely the approach of obtaining Backlund transformations by prolongation techniques. For KdV, MKdV and sine-Gordon equations the only difference consists in the application of a non-linear representation of the prolongation algebra other than the usual one. This representation can be obtained by a coordinate transformation of the prolongation variabl

Search for Bs -> mu mu and B0 -> mu mu decays in CMS

A search for the rare decays (Bs -> \mu \mu) and (B0 -> \mu\mu) performed in pp collisions at sqrt{s} = 7 TeV is presented. The data sample, collected by the CMS experiment at the LHC, corresponds to an integrated luminosity of 1.14 /fb. In both cases the number of events observed after all selection requirements is consistent with expectations from background and standard model signal predictions. The resulting upper limits on the branching fractions are BF(Bs -> \mu\mu) \mu \mu) < 4.6 * 10^{-9} at 95% confidence level (CL). Furthermore, the combination of the results of the search for the decay (Bs -> \mu \mu) by the CMS and LHCb experiments is presented. The combined upper limit is BF < 1.1 * 10^{-8} at 95% CL.Comment: Presented at the 2011 Hadron Collider Physics symposium (HCP-2011), Paris, France, November 14-18 2011, 3 pages, 5 figur

Prolongation structure and lax representation of the boomeron equation

An Estabrook-Wahlquist prolongation structure and a Lax representation for the Boomeron equation introduced by Calogero and Degasperis is determined

On Ideas in Motion in Baghdad and Beyond

Note on Damien Janos (ed.), Ideas in Motion in Baghdad and Beyond. Philosophical and Theological Exchanges between Christians and Muslims in the Third/Ninth and Fourth/Tenth Centuries, (Islamic History and Civilization. Studies and Texts, 124), Brill: Leiden–Boston, 201

Why does Low-Luminosity AGN Fueling Remain an Unsolved Problem?

Despite many years of effort, observational studies have not found a strong correlation between the presence of any proposed fueling mechanism and low-luminosity AGN. After a discussion of the mass requirements for fueling, I summarize this observational work and provide a number of hypotheses for why the nature of AGN fueling has remained unresolved. In particular, I stress the potential importance of the increasing number of candidate fueling mechanisms with decreasing mass accretion rate, the relevant spatial scales for different fueling mechanisms, and the lifetime of an individual episode of nuclear accretion. The episodic AGN lifetime is a particularly relevant complication if it is comparable to or shorter than the time that the responsible fueling mechanisms are observationally detectable. I conclude with a number of relatively accessible areas for future investigation.Comment: 7 pages, 2 figures. Invited review to appear in "The Interplay among Black Holes, Stars and ISM in Galactic Nuclei," Proc. IAU 222 (Gramado, Brazil), eds. Th. Storchi Bergmann, L.C. Ho, H.R. Schmit