We consider guarding a city of k vertical buildings, each having a rectangular base, by placing guards only at vertices. The aim is to use the smallest number of guards. The problem is a 2.5D variant of the traditional art gallery problem, and finds applications in urban security. We give upper and lower bounds on the number of guards needed for a few versions of the problem. Specifically, we p...

In football, injuries from opponent contact occur commonly in the lower extremities. FIFA the world's governing body for football requires players to wear shin guards. The aim of this study was to compare the protective effectiveness of polypropylene based shin guards with custom-made carbon fiber ones. Three commercial polypropylene shin guards (Adidas Predator™, Adidas UCL™, and Nike Mercuria...

We present a dynamical analysis of the central ∼ 1.3 square degrees of the cluster of galaxies Abell 1367, based on 273 redshift measurements (of which 119 are news). From the analysis of the 146 confirmed cluster members we derive a significantly non-Gaussian velocity distribution, with a mean location CBI = 6484±81 km s −1 and a scale SBI = 891 ± 58 km s −1. The cluster appears elongated from...

We study the temperature structure of the rich cluster of galaxies Abell 1367 using two independent methods of correcting for the ASCA PSF. The results of the two methods are in excellent agreement and give solid evidence of a strong and localized shock in the intracluster medium (ICM). Our analysis suggests that we are observing the merger of two subclusters. We find that the lower luminosity ...

the state of post revolutionary iran adopted economic policies over 1980-1988 which we can phrase redistributive economic policies. according to a part of revolutionary literature, adoption of these policies by the post revolutionary state is, partly, one of the structural features of that state. but it is not a main debate of this article. rather, basic concern of the article, as some of the p...

10 One of the earliest and most well known problems in computational geometry is 11 the so-called art gallery problem. The goal is to compute the minimum number of 12 guards needed to cover the interior of any polygon with n vertices; the guards are 13 to be placed on the vertices of the polygon. We consider the problem of guarding an 14 art gallery which is modeled as a polygon with curvilinea...

In this paper we study the art gallery problem, which is one of the fundamental problems in computational geometry. The objective is to place a minimum number of guards inside a simple polygon so that the guards together can see the whole polygon. We say that a guard at position x sees a point y if the line segment xy is contained in the polygon. Despite an extensive study of the art gallery pr...

The purpose of this study was to describe structural and functional characteristics of elite Serbian basketball players and to evaluate whether players in different positional roles have different physical and physiological profiles. Five men's basketball teams participated in the study and competed in the professional First National League. Physiological measurements were taken of 60 players d...