An X-ray Ñux-limited sample of nearby clusters of galaxies has been deÐned for observations of the Sunyaev-Zeldovich e †ect (SZE) to be carried out on the Owens Valley 5.5 m telescope at 32 GHz. The X-ray sample selection minimizes the systematic errors introduced by cluster elongation in the determination of Owing to their proximity, these clusters are well studied in the X-ray wave bands. The H 0 . measurement of the SZE in three of these clusters is reported in this paper : and [243^29 kK (A2256). These values have been corrected for radio source contamination, but have not been corrected for the beam dilution and switching (which are model dependent). There is an additional overall calibration uncertainty of 7%. If the temperature proÐle of the clusters is known, then the SZE provides a direct probe of the baryonic mass in the hot ionized phase of the medium. We Ðnd surface baryonic mass densities of (7.5^2.5) ] 1013Mpc~2 within the M _ 7@ .35 FWHM Gaussian beam of the 5.5 m telescope projected on the cluster centers. For A2142, A2256, and the Coma cluster previously observed by Herbig et al., we Ðnd a consistent value for the ratio of the SZE determined baryonic mass to the gravitational binding mass of h~1. Note M sze /M tot \ 0.061^0.011 that this is a lower limit on the total baryon fraction, as there may be signiÐcant contributions from other baryons. Comparison with the standard big bang nucleosynthesis prediction ) B h2 \ 0.013^0.02 gives a value for the cosmological density parameter of assuming our limit on the ) 0 h [ 0.21^0.05, baryon fraction in clusters applies to the universe as a whole. This density is in agreement with independently determined values from large-scale structure studies. Recent values for based upon deute-) B h2 rium abundances are outside the previously accepted range, and in combination with our data lead to signiÐcantly higher or lower Finally, we present preliminary determinations of the Hubble constant ) 0 . using X-ray models gleaned from the literature. The data from the three clusters, along with the results previously obtained using the same telescope on the Coma Cluster, yield a sample average value H 0 \ 54^14 km s~1 Mpc~1. We discuss the uncertainties in these results and future prospects for this method. Subject headings : cosmic microwave background È cosmology : observations È dark matter È distance scale È galaxies : clusters : general È intergalactic medium INTRODUCTIONThe scattering of the cosmic microwave background radiation by hot gas in clusters of galaxies, known as the Sunyaev-Zeldovich e †ect (SZE), has been recognized for over two decades as a potentially important tool for cosmological and astrophysical studies & Zeldovich (Sunyaev In the SZE, inverse Compton scattering boosts the 1980). microwave background photons to higher frequencies, upshifting and distorting the Planck blackbody spectrum. At low frequencies where the spectrum rises with frequency, this reduces the intensity of the CMB at a given frequency. At higher frequencies where th...

We compare the peculiar velocities of nearby SNe Ia with those predicted by the gravity fields of full sky galaxy catalogs. The method provides a powerful test of the gravitational instability paradigm and strong constraints on the density parameter β ≡ Ω 0.6 /b. For 24 SNe Ia within 10,000 km s −1 , we find the observed SNe Ia peculiar velocities are well modeled by the predictions derived from the 1.2 Jy IRAS survey and the Optical Redshift Survey (ORS). Our best β is 0.4 from IRAS, and 0.3 from the ORS, with β > 0.7 and β < 0.15 ruled out at 95% confidence levels from the IRAS comparison. Bootstrap resampling tests show these results to be robust in the mean and in its error. The precision of this technique will improve as additional nearby SNe Ia are discovered and monitored.subject headings: supernovae:general ; cosmology:observations, large-scale structure of universe-Local Group

The smooth muscle isoform of myosin light chain kinase (MLCK) is a Ca2+-calmodulin-activated kinase that is found in many tissues. It is particularly important for regulating smooth muscle contraction by phosphorylation of myosin. This review summarizes selected aspects of recent biochemical work on MLCK that pertains to its function in smooth muscle. In general, the focus of the review is on new findings, unresolved issues, and areas with the potential for high physiological significance that need further study. The review includes a concise summary of the structure, substrates, and enzyme activity, followed by a discussion of the factors that may limit the effective activity of MLCK in the muscle. The interactions of each of the many domains of MLCK with the proteins of the contractile apparatus, and the multi-domain interactions of MLCK that may control its behaviors in the cell are summarized. Finally, new in vitro approaches to studying the mechanism of phosphorylation of myosin are introduced.

We carry out N-body simulations of several non-Gaussian structure formation models, including Peebles' isocurvature cold dark matter model, cosmic string models, and a model with primordial voids. We compare the evolution of the cluster mass function in these simulations with that predicted by a modified version of the Press-Schechter formalism. We find that the Press-Schechter formula can accurately fit the cluster evolution over a wide range of redshifts for all of the models considered, with typical errors in the mass function of less than 25%, considerably smaller than the amount by which predictions for different models may differ. This work demonstrates that the Press-Schechter formalism can be used to place strong model independent constraints on non-Gaussianity in the universe.Comment: 11 pages, 12 postscipt figure