An unzipping of a polyhedron P is a cut-path through its vertices that unfolds P to a non-overlapping shape in the plane. It is an open problem to decide if every convex P has an unzipping. Here we show that there are nearly flat convex caps that have no unzipping. A convex cap is a “top” portion of a convex polyhedron; it has a boundary, i.e., it is not closed by a base.

In the analysis of cryptographic protocols, a treacherous set of terms is one from which an intruder can get access to what was intended to be secret, by adding on to the top of a sequence of elements of this set, a cap formed of symbols legally part of his/her knowledge. In this paper, we give sufficient conditions on the rewrite system modeling the intruder’s abilities, such as using encrypti...

In the projective space PG(N, q) over the Galois field of order q, N ≥ 3, an iterative step-by-step construction of complete caps by adding a new point on every step is considered. It is proved that uncovered points are evenly placed on the space. A natural conjecture on an estimate of the number of new covered points on every step is done. For a part of the iterative process, this estimate is ...

This paper shows how standard arguments supporting the imposition of price caps break down in the presence of demand uncertainty. In particular, though in the deterministic case the introduction or lowering of a price cap (above marginal cost) results in increased production, increased total welfare, decreased prices, and increased consumer welfare, we show that all of the above comparative sta...

Short-term increases in ambient air pollution have been associated with an increased incidence of acute cardiac events. We assessed the effect of inhalation exposure to concentrated ambient particles (CAPs) on myocardial ischemia in a canine model of coronary artery occlusion. Six mongrel dogs underwent thoracotomy for implantation of a vascular occluder around the left anterior descending coro...

Electroencephalography (EEG) is a common neuroscience technique that is more accessible to undergraduate programs than expensive techniques such as fMRI and single-cell recording. The use of EEG can provide undergraduates with firsthand neuroscience research experience without taking too many financial resources away from a program. There are multiple types of EEG equipment that can be used, in...

In vitro studies suggest that reactive oxygen species contribute to the cardiopulmonary toxicity of particulate air pollution. To evaluate the ability of particulate air pollution to promote oxidative stress and tissue damage in vivo, we studied a rat model of short-term exposure to concentrated ambient particles (CAPs). We exposed adult Sprague-Dawley rats to either CAPs aerosols (group 1; ave...

BACKGROUND Human controlled-exposure studies have assessed the impact of ambient fine particulate matter on cardiac autonomic function measured by heart rate variability (HRV), but whether these effects are modified by concomitant ozone exposure remains unknown. OBJECTIVE In this study we assessed the impact of O(3) and particulate matter exposure on HRV in humans. METHODS In a crossover de...