Classic texts: no. 15

No Classic Boundary Conditions

We consider the boundary value problem:    x(t) = f(t, x(t)), a ≤ t ≤ b, m > 1 x(a) = β0 ∆x ≡ x(b)− x(a) = βk+1, k = 0, ..., m− 2 where x(t) = (x(t), x ′ (t), ...., x(m−1)(t)), βi ∈ R, i = 0, ..., m − 1, and f is continuous at least in the interior of the domain of interest. We prove the existence and uniqueness of the solution under certain conditions.

How science survived: medieval manuscripts' "demography" and classic texts' extinction.

Determining what fraction of texts and manuscripts have survived from Antiquity and the Middle Ages has been highly problematic. Analyzing the transmission of texts as the "paleodemography" of their manuscripts yields definite and surprisingly high estimates. Parchment copies of the foremost medieval textbooks on arithmetical and calendrical calculation closely fit age distributions expected fo...

Ultra - violet absorption cross sections of isotopically substituted nitrous oxide species : 14 N 14 NO , 15 N 14 NO , 14 N 15 NO and 15 N 15 NO

The isotopically substituted nitrous oxide species 14N14NO, 15N14NO, 14N15NO and 15N15NO were investigated by ultra-violet (UV) absorption spectroscopy. High precision cross sections were obtained for the wavelength range 181 to 218 nm at temperatures of 233 and 283 K. These data are used to calculate photolytic isotopic fractionation constants as a function of wavelength. The fractionation con...

Classic Spotlight: Look, Max-No Math Required!

In 1952, Joshua and Esther Lederberg published a paper in the Journal of Bacteriology (1) that fully legitimized bacteria as genetic organisms, no different in principle from pea plants or fruit flies. In all cases, mutations are precipitous events that can generate stepwise changes in phenotype. The Lederbergs’ report first described the method of replica plating, now a venerable microbiologic...

Cover vol. 15, no. 6, December 2018