Mark D. Gross, Department of Planning and Design, University of Colorado People draw diagrams and sketches to think, argue, and communicate about problems in domains ranging from mechanical engineering to music. To understand a problem better, mathematician George Polya advised, “Draw a figure ... even if your problem is not a problem of geometry.”1 We can debate whether making a figure really ...

in order to comparison of weeds mechanical control for sugar beet, a rotary cultivator was designed and constructed in first year, and compared with other mechanical control in second year. five treatments, included: rotary hoe cultivator, furrower cultivator, rotary cultivator, no weeding and manual weeding were compared. experiment design was random complete blocks design (rcbd) with three re...

The purpose of this study was to analyze the type and frequency of defects in nickel-titanium rotary endodontic files after routine clinical use, and to draw conclusions regarding the reasons for failure. All of the files (total: 378, Quantec Series 2000) discarded after normal use from a specialist endodontic practice over 6 months were analyzed. Almost 50% of the files showed some visible def...

We propose an integrated model for eukaryotic DNA replication to explain the following problems: (1) How is DNA spooled through fixed sites of replication? (2) What and where are the helicases that unwind replicating DNA? (3) Why are the best candidates for replicative helicases, namely mini-chromosome maintenance (MCM) proteins, not concentrated at the replication fork? (4) How do MCM proteins...

A polygon A in a configuration C is called rotary if C admits an automorphism which acts upon A as a one-step rotation. We study rotary polygons and their orbits under the group of automorphisms (and antimorphisms) of C. We determine the number of such orbits for several symmetry types of rotary polygons in the case when C is flag-transitive. As an example, we provide tables of flag-transitive ...