In grade school, students learn a standard set of Euclidean triangles. Among this set, the usual 45–45–90 and 30–60–90 triangles are the only right triangles with rational angles and side lengths each containing at most one square root. Are there any other such right triangles? We answer this question completely and present an elegant complement called Ailles’ rectangle that deserves to be in e...

The recent development of powerful cryptographic techniques has caused a number of public policy issues to become significant. The three most prominent issues are (1) export control, (2) key escrow, and (3) anonymity. These represent tradeoffs between different societal objectives: (1) commerce/national-security and (2,3) privacy/law-enforcement. Some discussion of cryptographic policy issues c...

1. Two-dimensionalists often rely on the assumption that “a posteriori information only tells us about our world” (Chalmers (1996), 137). This assumption backs their rejection of what Chalmers calls “strong metaphysical necessities”, since such necessities would be forever beyond our epistemic reach. But I see no reason to accept this epistemological constraint, and much reason to reject it. No...

Description : Diffuse low-grade gliomas (WHO grade II) are a sub-group of rare and heterogeneous primary brain tumors that usually occur in young patients living a normal life until the onset of a first seizure. A good understanding of the natural history of these gliomas namely: their steady progression, infiltration along white matter fibers and especially the risk of malignant transformation...

colorectal cancer is the second leading cause of cancer death worldwide. through risk assessment of malignancy in polyps, screening programs can achieve the best results. this study aimed to determine the association between the grade of dysplasia and the location of colorectal polyps. 240 colorectal adenomatous polyps which were referred to department of pathology at rasoul-e-akram hospital be...

background and objectives: gliomas are the most prevalent primary brain tumors. the purpose of this retrospective cohort study was evaluation of clinical trend and prognosis of patients with brain glioma and effective factors in prognosis. materials and methods: hundred and forty-five patients with supratentorial brain glioma, treated in shahid mostafa khomeini & hazrat-e-rasool hospitals i...

The paper describes a scheduling system for a high-grade steel making plant. Because very specialized steel grades are produced the variety of the chemical analysis of the heats is very high and the lot sizes are small. One of the most constraining factors in the production is the infiltration of chemical elements between consecutive heats in the electric arc furnace. To find a schedule that vi...