For a family of geometric objects in the plane F = {S1, . . . , Sn}, define χ(F) as the least integer l such that the elements of F can be colored with l colors, in such a way that any two intersecting objects have distinct colors. When F is a set of Jordan regions that may only intersect on their boundaries, and such that any point of the plane is contained in at most k regions, it can be prov...

We developed a model of pathogen dissemination in the outpatient clinic that incorporates key kinetic aspects of the transmission process, as well as uncertainty regarding whether or not each incident patient is contagious. Assigning appointments late in the day to patients suspected of being infectious should decrease pathogen dissemination.

We examine the behaviour of the zeros of the real and imaginary parts of ξ(s) on the vertical line Rs = 1/2 + λ, for λ 6= 0. This can be rephrased in terms of studying the zeros of families of entire functions A(s) = 1 2 (ξ(s+λ)+ξ(s−λ)) and B(s) = 1 2i (ξ(s+λ)−ξ(s−λ)). We will prove some unconditional analogues of results appearing in [3], specifically that the normalized spacings of the zeros ...

A boundary sequence is a good representation of arbitrary shaped regions, but not directly used in computing shape features such as area, centroid, orientation, and so forth. In this paper, we show that the shape features can be easily computed by using cross-sections derived from a boundary sequence. The cross-sections are vertical line segments in the region and can be determined by tracing t...

Previous experimental research has shown that thin financial markets fail to fully equilibrate, in contrast with thick markets. A specific type of market risk is conjectured to be the reason, namely, the risk of partial execution of desired portfolio rearrangements in a system of parallel, unconnected double auction markets. This market risk causes liquidity to dry up before equilibrium is reac...

BACKGROUND A comprehensive approach to preventing HIV infection in infants has been recommended, including: (a) preventing HIV in young women, (b) reducing unintended pregnancies among HIV-infected women, (c) preventing vertical transmission (PMTCT), and (d) providing care, treatment, and support to HIV-infected women and their families. Most attention has been given to preventing vertical tran...

Quality specialization may help insulate workers in developed countries from low-wage country competition by weakening the convergence in goods and factor prices implied by international trade. I develop a model in which vulnerability to low-wage country competition decreases with a product market’s degree of vertical differentiation. To test the implications of this model, I measure countries’...

This paper considers reconngurations of polygons, where each polygon edge is a rigid link, no two of which can cross during the motion. We prove that one can reconngure any monotone polygon into a convex polygon; a polygon is monotone if any vertical line intersects the interior at a (possibly empty) interval. Our algorithm computes in O(n 2) time a sequence of O(n 2) moves, each of which rotat...

The problem of fake products by counterfeiters and unregistered manufacturers is real and constitutes a major threat to the health and safety of the Nigerian population. A descriptive study was carried out on the present means of identifying authentic products and fake ones by the members of the society in this work. The sources of information for this work include online journals, NAFDAC sites...

Article history: Received: 28.11.2014. Received in revised form: 5.3.2015. Accepted: 7.3.2015. This paper proposes a new DFT Architecture that contains three test scan modes. The test data could be interval broadcast to scan chains whenever the data in corresponding locations are compatible. Compared with the conventional broadcast scan architecture, the proposed architecture achieves better co...