Dichloro(diphenylarsino)ruthenium(III) & Its Reactions with Some Nitrogen Donors

534-53

Observation of persistent flow of a Bose-Einstein condensate in a toroidal trap

We have observed the persistent flow of Bose-condensed atoms in a toroidal trap. The flow persists without decay for up to 10 s, limited only by experimental factors such as drift and trap lifetime. The quantized rotation was initiated by transferring one unit, $\hbar$, of the orbital angular momentum from Laguerre-Gaussian photons to each atom. Stable flow was only possible when the trap was multiply-connected, and was observed with a BEC fraction as small as 15%. We also created flow with two units of angular momentum, and observed its splitting into two singly-charged vortices when the trap geometry was changed from multiply- to simply-connected.Comment: 1 file, 5 figure

Probabilistic combinatorial optimization: Moments, semidefinite programming, and asymptotic bounds

10.1137/S1052623403430610SIAM Journal on Optimization151185-20

Major Galaxy Mergers and the Growth of Supermassive Black Holes in Quasars

Despite observed strong correlations between central supermassive black holes (SMBHs) and star-formation in galactic nuclei, uncertainties exist in our understanding of their coupling. We present observations of the ratio of heavily-obscured to unobscured quasars as a function of cosmic epoch up to z~3, and show that a simple physical model describing mergers of massive, gas-rich galaxies matches these observations. In the context of this model, every obscured and unobscured quasar represent two distinct phases that result from a massive galaxy merger event. Much of the mass growth of the SMBH occurs during the heavily-obscured phase. These observations provide additional evidence for a causal link between gas-rich galaxy mergers, accretion onto the nuclear SMBH and coeval star formation.Comment: Accepted for publication in Science. Published by Science Express on March 25th. 17 pages, 5 figures, including supplemental online materia

Antibacterial properties of Passiflora foetida L. – a common exotic medicinal plant

Passiflora foetida L. (stinking passion flower) is an exotic medicinal vine. The antibacterial properties of leaf and fruit (ethanol and acetone) extracts were screened against four human pathogenic bacteria i.e. Pseudomonas putida, Vibrio cholerae, Shigella flexneri and Streptococcus pyogenes by well-in agar method. The results showed the leaf extract having remarkable activity against all bacterial pathogens compared to fruits. This study supports, the traditional medicines (herbal extracts) to cure manydiseases like diarrhea, intestinal tract, throat, ear infections, fever and skin diseases

An Unexpectedly Swift Rise in the Gamma-ray Burst Rate

The association of long gamma-ray bursts with supernovae naturally suggests that the cosmic GRB rate should trace the star formation history. Finding otherwise would provide important clues concerning these rare, curious phenomena. Using a new estimate of Swift GRB energetics to construct a sample of 36 luminous GRBs with redshifts in the range z=0-4, we find evidence of enhanced evolution in the GRB rate, with ~4 times as many GRBs observed at z~4 than expected from star formation measurements. This direct and empirical demonstration of needed additional evolution is a new result. It is consistent with theoretical expectations from metallicity effects, but other causes remain possible, and we consider them systematically.Comment: 4 pages, 4 figures; minor changes to agree with published versio