Shared birthdays

Oo-koo-he " He was barely able to believe his ears. It must have been incredible to him that this strange, weak creature, like something from another world, should directly inquire after a secret tradition of his people. I have no idea how many cultural conventions were overlooked, but after a bit more conversation, or what passes for conversation between people who share no common language, I was sure that he would try to help me. Days later, on my twenty-fifth birthday, I was brought a tarry goo wrapped into little leaf packets. I was never able to obtain a hallucinogenic experience from this material, but later analysis by the chemists of the Karolinska Institute in Stockholm confirmed the presence of di-methyltryptamine. Demetrius had been as good as his name. 

Table 1 lists some common separation techniques and typical peak capacities. Cursory examination would suggest that a carefully chosen separation technique and a single dimension detector would be sufficient to separate mixtures containing up to nc components. This conclusion however would be incorrect. Components in mixtures will have a distribution of retention times with no a priori way to avoid coelution. The probability of coelution is much like the old party trick of showing that in a roomful of 40 or more people, two people are very likely to share the same birthday (try it ). 

In a room with only two people, the second person has 365 out of 366 (remember leap years) chance of not having the same birthday. Adding an additional person to the room, the chance that the third person does not share either of the other two birthdays is given by 364 divided by 366. But the chance that none in the room share the same birthday is joint, i.e., the... 

After laying the foundation for the first edition, Erich Ziegler has been able to pass on the editorship within the family, sharing his ongoing passion for the world of flavours. This 2 edition had initially been scheduled as homage on the occasion of his 80 birthday in 2005, a target the large pool of authors could, however, not fulfil completely. 

I am deeply indebted to Martin Quack for his stimulus, for sharing ideas and insight as well as for his support and help in various ways. Therefore, this chapter is dedicated to him on the occasion of his 55th birthday. I thank Jurgen Stohner for his comments on the manuscript and for stimulating discussions on various aspects of molecular parity violation. And last but not least I thank my student Guido Laubender for his dedicated work. 

The volume of chemical literature which is published seems to increase each year, and the subjects covered in this chapter share in this increase. A large number of references have been collected through Chemical Abstracts volumes 120 and 121 and a selection of these is presented here. The death of Professor R. K. Robins, a prolific contributor to the field of AT-heterocyclic chemistry, occured in 1992 and several of the papers referred to in this chapter were dedicated to his memory. Also, during the period covered in the chapter, a number of papers were dedicated to mark the 70th birthday of Professor E. C. Taylor, another tireless worker whose contributions to iV-heterocyclic chemistry are frequently mentioned in this chapter and elsewhere. 

From the birthday of the modem chemistry, i.e., since Boyle had used for the first time a coherent atomic theory in science in his 1661 famous book The Skeptical Chymist, the fundamental principles and concepts of matter stmcture were constantly shared by the physics and chemistry. However, the divorce of chemistry from physics would have to come with many occasions by means of classical chemical concepts, e g., valence, chemical bond, and electronegativity. The mystery by which the atoms are kept together and still preserving their intimate properties was searched by great minds, from Newton to Lewis, being the key furnished only with the advent of quantum theory. Within this new paradigm of matter there is the feeling that the physics and chemistry are united under the actual common... 

The essential feature of all methods is that the analyte we wish to measure must not come out at the same time (co-elute) as anything else that would also be detected and confused with the authentic analyte. Unfortunately co-elution is statistically hard to avoid. Many people know the paradox that if 23 or more people meet in a room, it is more likely than not that two will share a birthday. Translated into chromatography terms, if 23 chemicals are separated at random... 

When this writer was asked to contribute to the volume of essays dedicated to Severo Ochoa on his 70th birthday, he started to think about a subject suitable for such an occasion. Severo and this writer have been close friends for almost 40 years. This is in spite of the fact that our interpretation of the significance of science for the human life does not always appear to be identical. But one of the basic elements of our friendship seems to be our sharing of a deep respect for the variety of men. This short essay which attempts to deal with the relevance of biochemistry, as we know it today, for the understanding of the variety of life seems to be a suitable contribution in honor of a very eminent scientist and a dear friend. 

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