This is a survey on known results and open problems about closed aspherical manifolds, i.e., connected closed manifolds whose universal coverings are contractible. Many examples come from certain kinds of non-positive curvature conditions. The property aspherical, which is a purely homotopy theoretical condition, implies many striking results about the geometry and analysis of the manifold or i...

Previous studies have explained the shapes of LBV nebu-lae, such as η Car, by invoking the interaction of an isotropic fast wind with a previously deposited, slow aspherical wind (a " slow torus "). In this work I focus on the opposite scenario where an aspherical fast wind expands into a previously deposited isotropic slow wind. Using high resolution hydrodynamic simulations which include the ...

We discuss a method to control the coating thickness deposited onto large and strongly curved optics by ion beam sputtering. The technique uses an original design of the mask used to screen part of the sputtered materials. A first multielement mask is calculated from the measured two-dimensional coating thickness distribution. Then, by means of an iterative process, the final mask is designed. ...

We give two versions of relative hyperbolization. We use the first version to prove that if (each component of) a closed manifold M is aspherical and if M is a boundary, then it is the boundary of an aspherical manifold.

We show that the finitely presented groups with unsolvable word problem given by the Boone-Britton construction have cohomological dimension 2. More precisely we show these groups can be obtained from a free group by successively forming HNN-extensions where the associated subgroups are finitely generated free groups. Also the presentations obtained for these groups are aspherical. Using this w...

AIMS To compare the quality of vision in pseudophakic patients implanted with aspherical and spherical intraocular lenses (IOLs). MATERIALS AND METHODS Randomized prospective longitudinal intrapatient comparison between aspherical and spherical IOLs performed on 22 patients who underwent bilateral cataract surgery. Best corrected visual acuity, subjective contrast sensitivity, Strehl ratio an...

The scanning long-wave optical test system (SLOTS) is under development at the University of Arizona to provide rapid and accurate measurements of aspherical optical surfaces during the grinding stage. It is based on the success of the software configurable optical test system (SCOTS) which uses visible light to measure surface slopes. Working at long wave infrared (LWIR, 7-14 um), SLOTS measur...

In this paper we address the issue of the origin of LBV bipolar bubbles. Previous studies have explained the shapes of LBV nebulae, such as η Car, by invoking the interaction of an isotropic fast wind with a previously deposited, slow aspherical wind (a “slow torus”). In this paper we focus on the opposite scenario where an aspherical fast wind expands into a previously deposited isotropic slow...

Aspherical explosion models for the hypernova (hyper-energetic supernova) SN 1998bw are presented. Nucleosynthesis in aspherical explosions is examined with a two-dimensional hydrodynamical code and a detailed nuclear reaction network. Aspherical explosions lead to a strong α-rich freezeout, thus enhancing the abundance ratios [Ca, Ti, and Zn / Fe] in the ejecta. The nebular line profiles of th...