Marcinkiewicz multipliers are L bounded for 1 < p < ∞ on the Heisenberg group H ≃ C × R (D. Muller, F. Ricci and E. M. Stein [25], [26]). This is surprising in that this class of multipliers is invariant under a two parameter group of dilations on C × R, while there is no two parameter group of automorphic dilations on H. This lack of automorphic dilations underlies the inability of classical o...

It is shown that the Hermitian-symmetric space CP1 × CP1 × CP1 and the flag manifold F1,2 endowed with any left invariant metric admit no compatible integrable almost complex structures (even locally) different from the invariant ones. As an application it is proved that any stable harmonic immersion from F1,2 equipped with an invariant metric into an irreducible Hermitian symmetric space of co...

The tubular network is a critical part of the endoplasmic reticulum (ER). The network is shaped by the reticulons and REEPs/Yop1p that generate tubules by inducing high membrane curvature, and the dynamin-like GTPases atlastin and Sey1p/RHD3 that connect tubules via membrane fusion. However, the specific functions of this ER domain are not clear. Here, we isolated tubule-based microsomes from S...

In this note, we characterize the graphs (1-skeletons) of some piecewise Euclidean simplicial and cubical complexes having nonpositive curvature in the sense of Gromov’s CAT(0) inequality. Each such cell complex K is simply connected and obeys a certain flag condition. It turns out that if, in addition, all maximal cells are either regular Euclidean cubes or right Euclidean triangles glued in a...

We consider a triality between the Zermelo navigation problem, the geodesic flow on a Finslerian geometry of Randers type, and spacetimes in one dimension higher admitting a timelike conformal Killing vector field. From the latter viewpoint, the data of the Zermelo problem are encoded in a (conformally) Painlevé-Gullstrand form of the spacetime metric, whereas the data of the Randers problem ar...

Security competitions have become a popular way to foster security education by creating a competitive environment in which participants go beyond the effort usually required in traditional security courses. Live security competitions (also called “Capture The Flag,” or CTF competitions) are particularly well-suited to support handson experience, as they usually have both an attack and a defens...

BACKGROUND Flag (touch or intramural) football is a popular sport among the U.S. Air Force (USAF) active duty population and causes a substantial number of lost-workday injuries. The purpose of this study is to describe the mechanisms of flag-football injuries to better identify effective countermeasures. METHODS The data were derived from safety reports obtained from the USAF Ground Safety A...