The notion of exterior space consists of a topological space together with a certain nonempty family of open subsets that is thought of as a ‘system of open neighborhoods at infinity’ while an exterior map is a continuous map which is ‘continuous at infinity’. The category of spaces and proper maps is a subcategory of the category of exterior spaces. In this paper we show that the category of e...

Background: Adrenal hematoma is a very rare acquired cause of neonatal hypertension. In this study, we report a case of neonatal hypertension associated with adrenal hematoma. A male neonate was immediately transferred to our neonatal intensive care unit after delivery due to meconium aspiration. He needed to be on mechanical ventilation support. During his hospital stay, hospital records showe...

Attention is commonly thought to be important for managing the limited resources available in sensory areas of the neocortex. Here we present an alternative view that attention arises as a byproduct of circuits centered on the basal ganglia involved in value-based decision making. The central idea is that decision making depends on properly estimating the current state of the animal and its env...

Let V be a four-dimensional real vector space with a fixed orientation. Then the wedge product can be viewed, up to a positive factor, as a canonical quadratic form of signature (3, 3) on the six-dimensional space ΛV . This gives a homomorphism from the identity component of the general linear group GL(V ) to the conformal group of the indefinite form, which is a local isomorphism. The signific...

The Hodge dual operator ∗ is one of the 3 basic operations on differential forms. (The other 2 are wedge product ∧ and exterior differentiation d.) However most treatments consider only positive-definite inner products, and there are at least 2 standard ways of generalizing this to inner products of arbitrary signature. We outline here a construction of the Hodge dual operator which works for a...

Butt fusion is an effective method for joining high density polyethylene (HDPE) pipe on job sites. However, there is lack of quantitative methods to evaluate pipe joint quality. The objective of this study was to develop such a quantitative approach in order to determine the effect of joint contamination on the quality of the fused joints. The study included testing a total of 21 butt-fused HDP...