Akiyama and Goto have proposed a cryptosystem based on rational points on curves over function fields (stated in the equivalent form of sections of fibrations on surfaces). It is easy to construct a curve passing through a few given points, but finding the points, given only the curve, is hard. We show how to break their original cryptosystem by using algebraic points instead of rational points...

We have collected all of the published photometry for GRB 990123 and GRB 990510, the first two gamma-ray bursts where breaks were seen in the light curves of their optical afterglows, and determined the shapes of their light curves and the break times. These parameters were used to investigate the physical mechanisms responsible for the breaks and the nature of the ambient medium that the burst...

In this research paper, an experimental breakthrough curve for citric acid in an adsorption recovery process was determined by an ion-exchange resin in 20, 35, 55 °C. Also, a mathematical model for breakthrough curve was presented. Among ion exchange resins that have been experienced, many weak and strong basic anionic resins are available such as, IRA-92, IRA-93, IRA-420 and IRA-458 and all of...

abstract present study used translog cost function for determining break point of paddy farms. requested data set include inputs’ prices and quantities, and production amounts had been acquired from 500 rice farmers of guilan province at 2009. model used in this study is seemingly unrelated regressions (sur). the results showed that labor and pesticides had the highest and lowest share of produ...

The initial value problem of an integrable system, such as the Nonlinear Schrödinger equation, is solved by subjecting the linear eigenvalue problem arising from its Lax pair to inverse scattering, and, thus, transforming it to a matrix Riemann-Hilbert problem (RHP) in the spectral variable. In the semiclassical limit, the method of nonlinear steepest descent ([4], [5]), supplemented by the g-f...

Two rational primes p, q are called dual elliptic if there is an elliptic curve E mod p with q points. They were introduced as an interesting means for combining the strengths of the elliptic curve and cyclotomy primality proving algorithms. By extending to elliptic curves some notions of galois theory of rings used in the cyclotomy primality tests, one obtains a new algorithm which has heurist...

Knowledge of transport and degradation of polycyclic aromatic hydrocarbons (PAHs) is important in assessing PAH contamination of soils and water resources. The transport of naphthalene, anthracene, pyrene and phenanthrene was determined in a contaminated calcareous soil obtained from the Shadegan wetland (Khozestan, Iran) considering a column study in laboratory conditions. The PAHs were added ...