A new compilation of data on Local Group members shows that low-luminosity early-type galaxies are, at the 99% confidence level, more strongly concentrated in the M 31, and Galactic sub-clumps, than are dwarf irregular galaxies. It is not yet clear if star formation continued longer in dSph galaxies that are located far from M 31 and the Galaxy, than it did in those that are not associated with the Andromeda and Milky Way sub-clumps of the Local Group. Key words: galaxies: clustering - galaxies: Local Group

Sidney van den Bergh

A radiative deuteron-proton capture experiment was carried out at KVI using polarized-deuteron beams at incident energies of 55, 66.5, and 90 MeV/nucleon. Vector and tensor-analyzing powers were obtained for a large angular range. The results are interpreted with the help of Faddeev calculations, which are based on modern two- and three-nucleon potentials. Our data are described well by the calculations, and disagree significantly with the observed tensor anomaly at RCNP.

A. A. Mehmandoost-Khajeh-Dad H. R. Amir-Ahmadi J. C. S. Bacelar A. M. van~den~Berg R. Castelijns A. Deltuva E. D. van~Garderen W. Glöckle J. Golak N. Kalantar-Nayestanaki H. Kamada M. Kiš R. Koohi-Fayegh-Dehkordi H. Löhner M. Mahjour-Shafiei H. Mardanpur J. G. Messchendorp A. Nogga P. Sauer S. V. Shende R. Skibinski H. Witała H. J. Wörtche

We obtain upper bounds on the heat content and on the torsional rigidity of a complete Riemannian manifold M, assuming a generalized Hardy inequality for the Dirichlet Laplacian on M.

Michiel van den Berg Peter B. Gilkey

We propose a new algorithm for the optimization of convex functions over a polyhedral set in Rn. The algorithm extends the spectral projected-gradient method with limited-memory BFGS iterates restricted to the present face whenever possible. We prove convergence of the algorithm under suitable conditions and apply the algorithm to solve the Lasso problem, and consequently, the basis-pursuit denoise problem through the root-finding framework proposed by van den Berg and Friedlander [SIAM Journal on Scientific Computing, 31(2), 2008]. The algorithm is especially well suited to simple domains and could also be used to solve bound-constrained problems as well as problems restricted to the simplex.

Ewout van den Berg

Decay via proton emission of isobaric analog states (IAS's) in $^{91}{Nb}$ was studied using the $^{90}{Zr}(\alpha,t)$ reaction at $E_\alpha$=180 MeV. This study provides information about the damping mechanism of these states. Decay to the ground state and low-lying phonon states in $^{90}{Zr}$ was observed. The experimental data are compared with theoretical predictions wherein the IAS `single-particle' proton escape widths are calculated in a continuum RPA approach. The branching ratios for decay to the phonon states are explained using a simple model.

H. K. T. van der Molen H. Akimune A. M. van den Berg I. Daito H. Fujimura Y. Fujita M. Fujiwara M. N. Harakeh F. Ihara T. Inomato K. Ishibashi J. Janecke N. Kalantar-Nayestanaki H. Laurent I. Lhenry T. W. O'Donnell V. A. Rodin A. Tamii H. Toyokawa M. H. Urin H. Yoshida M. Yosoi

The history of the discovery of dark matter in the Universe is briefly reviewed. Special emphasis is placed on the early work by Zwicky (1933), Smith (1936), Babcock (1939) and Oort (1940).

Sidney van den Bergh

We obtain bounds for the expected loss of torsional rigidity of a cylinder $\Omega_L=(-L/2,L/2) \times \Omega\subset \R^3$ of length $L$ due to a Brownian fracture that starts at a random point in $\Omega_L,$ and runs until the first time it exits $\Omega_L$. These bounds are expressed in terms of the geometry of the cross-section $\Omega \subset \R^2$. It is shown that if $\Omega$ is a disc with radius $R$, then in the limit as $L \rightarrow \infty$ the expected loss of torsional rigidity equals $cR^5$ for some $c\in (0,\infty)$. We derive bounds for $c$ in terms of the expected Newtonian capacity of the trace of a Brownian path that starts at the centre of a ball in $\R^3$ with radius $1,$ and runs until the first time it exits this ball.

M. van den Berg F. den Hollander

Estimates are obtained for the expected volume of intersection of independent Wiener sausages in Euclidean space in the small time limit. The asymptotic behaviour of the weighted diagonal heat kernel norm on compact Riemannian manifolds with smooth boundary is obtained in the small time limit

M. van den Berg P. Gilkey

We study the heat content asymptotics with either Dirichlet or Robin boundary conditions where the initial temperature exhibits radial blowup near the boundary. We show that there is a complete small-time asymptotic expansion and give explicit geometrical formulas for the first few terms in the expansion.

M. van den Berg P. Gilkey R. Seeley

We study the weighted heat trace asymptotics of an operator of Laplace type with Dirichlet boundary conditions where the weight function exhibits radial blowup. We give formulas for the first few terms in the expansion in terms of geometrical data.

M. van den Berg P. Gilkey K. Kirsten R. Seeley