background: occupational lead poisoning is a health problem in iran. it has not previously been studied in traditional tile makers. objective: to determine the prevalence of lead poisoning and its complications in traditional tile workers in mashhad, northwest of iran. methods: we visited workers in two traditional tile factories and collected data by direct history taking and physical examinat...

Tile responses of artificial neural networks to experimental and model generated inputs are compared for detection of damage in twisted fan blades using electronic holography. Tile training set inputs, for this work, are experimentally generated cllaracteristic pattenls of tile vibrating blades. Tile outputs are damage flag indicators or second derivatives of tile sensitivity vector projected d...

Buyer cooperatives, buyer alliances, and horizontal mergers are often perceived as attempts to increase buyer power. While prior theoretical and empirical work has emphasized that buyer size can increase buyer surplus, I show that even a small group of buyers with heterogeneous preferences can increase price competition among rival sellers by forming a buyer group and committing to buy exclusiv...

Autoantibodies may be found years before an autoimmune disease becomes clinically apparent. For systemic lupus erythematosus (SLE), those to RNA-binding proteins, to phospholipids, and to double-stranded DNA, in particular, have been found in sera of SLE patients years before the diagnosis was made. New data now show in an unbiased way that, in patients with early SLE, no single antibody class ...

We extend the study of Akiyama’s tile-makers: surfaces whose developments all tile the plane. First, we prove that the developments of Akiyama’s tile-makers are the prototiles that tile the plane isohedrally with rotation and without reflection. Second, we give a simple characterization of all closed (boundaryless) tile-makers and give three new tile-makers not known to Akiyama. Finally, we pro...

We show that the Tile Assembly Model exhibits a strong notion of universality where the goal is to give a single tile assembly system that simulates the behavior of any other tile assembly system. We give a tile assembly system that is capable of simulating a very wide class of tile systems, including itself. Specifically, we give a tile set that simulates the assembly of any tile assembly syst...