Roca dels Bous (archaeological site) interesting archaeological site indeed. Furthermore, it is to be noted that the samples used for the 14C AMS dating were obtained from deep strata at the site. The oldest Neanderthal sites known in the nearby areas date back to around 40,000 BP. The first settlements attributed to “anatomically modern” Homo sapiens sapiens in Northern Spain are dated around 39,000-38,000 BP. All this would suggest that Neanderthals could have persisted in this particular area longer than previously believed, preceding the arrival of the first Homo sapiens to the area. Research work began in 1988. This wide period of time has contributed
Kinetic isotope effect "k"/"k", of 1.0133±0.0002 along with a hydrogen kinetic isotope effect of 3.2 at the leaving hydrogen. Similarly, combining nitrogen and hydrogen isotope effects was used to show that syn eliminations of simple ammonium salts also follow a concerted mechanism, which was a question of debate before. In the following two reactions of 2-phenylcyclopentyltrimethylammonium ion with ethoxide, both of which yield 1-phenylcyclopentene, both isomers exhibited a nitrogen isotope effect "k"/"k" at 60C. Although the reaction of the trans isomer, which follows syn elimination, has a smaller nitrogen kinetic isotope effect (1.0064) compared to the cis isomer which undergoes anti elimination (1.0108),