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...

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...

A new aperiodic tile set containing only 13 tiles over 5 colors is presented. Its construction is based on a technique recently developed by J. Kari. The tilings simulate behavior of sequential machines that multiply real numbers in balanced representations by real constants.

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 examina...

Thanks to a careful study of elementary properties of two-bytwo substitution systems, we give a complete self-contained elementary construction of an aperiodic tile set and sketch how to use this tile set to elementary prove the undecidability of the classical Domino Problem.

Although the design of DNA tiles has been optimised for efficient and specific self-assembly, assembly errors occur so often that applications for molecular computation remain limited. We propose the use of an enveloped tile consisting of a DXbase tile that carries a protector tile to suppress erroneous tile assembly. The design of the enveloped tile promotes the dissociation of the protector t...

this is a field study, tile purpose was to measure and compare the use'. effectiveness and complication of iranian and foreign intra utcrin device ill women who have been using the mentioned method f or birth control ill family planning clinics of the university of medical sciences of iran (/ 993). iii this research by pois son statistical selection, 1620 samples of active record'! oj...