A new steroidal saponin was isolated from the leaves of Agave shrevei Gentry. Its structure was established as 26-(beta-D-glucopyranosyloxy)-22-methoxy-3-(O-beta-D-glucopyranosyl-(1-->2)O-[O-beta-D-glucopyranosyl-(1-->4)-O-[O-beta-D-glucopyranosyl-(1-->6)]-O-beta-D-glucopyranosyl(1-->4)-beta-D-galactopyranosyl]oxy)-(3beta,5alpha,25R)-furostane. The structural identification was performed using ...

Hippocrates to the end of the sixteenth century. We may group them under three periods?1. Before the Christian era; 2. From the commencement of the Christian era to the fall of Rome; 3. (after the break of the ten centuries of the Dark Ages) From 1500 a.d. to the close of the sixteenth century. Each of these periods begins with an important name?the first with Hippocrates; the second with Soran...

The most prominent “schools” or programs for the foundations of mathematics that took shape in the first third of the 20th century emerged directly from, or in response to, developments in mathematics and logic in the latter part of the 19th century. The first of these programs, so-called logicism, had as its aim the reduction of mathematics to purely logical principles. In order to understand ...

The Industrial Revolution began in the last half of eighteenth century in the United Kingdom where the steam engine and other mechanical innovations dramatically increased industrial output and drastically change social systems. The second wave of industrialization came with mass production methods represented especially by the electrical and automotive industry at the beginning of the twentiet...

The first objective of this paper is carry out three experiments intended to evaluate authorship attribution methods based on three test-collections available in three different languages (English, French, and German). In the first we represent and categorize 52 text excerpts written by nine authors and taken from 19th century English novels. In the second we work with 44 segments from French n...