In this note, we study the total positivity of a class of infinite recursive matrices that depend on three infinite sets of independent variables and on an integer parameter. We give a simple algebraic proof and provide a few examples.

where n = dim M and 6» = ith Betti number of M ( = dim of Hi(M; Q)). Thus the geometric property of M having a nonzero vector field is expressed in terms of the algebraic invariant xM. We will discuss extensions of this idea to vector ^-fields, fields of ^-planes, and foliations of manifolds. All manifolds considered will be connected, smooth and without boundary; all maps will be continuous. F...

We generalize wave maps to biwave maps. We prove that the composition of a biwave map and a totally geodesic map is a biwave map. We give examples of biwave nonwave maps. We show that if f is a biwave map into a Riemannian manifold under certain circumstance, then f is a wave map. We verify that if f is a stable biwave map into a Riemannian manifold with positive constant sectional curvature sa...

In 1932 Ettore Majorana proposed an infinite-component relativistic wave equation for particles of arbitrary integer and half-integer spin. In the late 80s and early 90s it was found that the higher-derivative geometric particle models underlie the Majorana equation, and that its (2+1)dimensional analogue provides with a natural basis for the description of relativistic anyons. We review these ...

OBJECTIVE As a result of the California heat wave in July 2006, county coroners reported that the high temperatures during that period caused approximately 147 deaths. However, heat wave-related deaths are likely to be underreported due to a lack of a clear case definition and the multi-factorial nature of heat-related mortality. Public health policy suggests a need for a careful assessment of ...

Wave reflections affect the proximal aortic pressure and flow waves and play a role in systolic hypertension. A measure of wave reflection, receiving much attention, is the augmentation index (AI), the ratio of the secondary rise in pressure and pulse pressure. AI can be limiting, because it depends not only on the magnitude of wave reflection but also on wave shapes and timing of incident and ...

OBJECTIVE The present study's aim was to analyze the late responses' parameters in order to determine the utility of each one. METHODS The study, conducted on a total of 325 patients with entrapment neuropathy of the median nerve and 36 with entrapment neuropathy of the ulnar nerve, included the bilateral evaluation of the median and the ulnar nerve and analysis of 20 F-wave and 4 A-wave para...

The existence of a Brewster wave number is demonstrated for the case of plane-wave reflection by a specularly smooth, planar interface joining two homogeneous, linearly elastic, isotropic solid half-spaces. Such a wave number is numerically shown to exist for two material combinations: steel-aluminum and steel-brass. The wave number can be such that plane waves are either propagating or evanesc...

Climate change and human health are intertwined. The heat waves in Chicago, in 1995, and in Paris, in 2003, followed by Hurricane Katrina_s destruction of New Orleans, raised awareness of the risks faced by vulnerable older people. Many cities have responded by announcing emergency preparedness plans; some of these plans have already been tested. Last summer, from July 27 to August 5, New York ...