Many fundamental processes in chemistry and biology occur on extremely short time scales inaccessible by conventional analytical methods. Here we show how femtosecond transient absorption spectroscopy reveals intimate details of key molecular processes such as electron or energy transfer. We describe in detail experimental set-up and discuss various parameters necessary to obtain desired information. Application of the method is demonstrated on peridinin-chlorophyll protein from marine photosynthetic organisms, in which we follow dynamics of energy transfer between carotenoids and chlorophylls., Petr Hříbek, Marcel Fuciman, Pavel Chábera, Tomáš Polívka., and Obsahuje bibliografii
In the 19th century, the town of Příbor and its environs was one of the regions with an extended crib making tradition. Towards the end of the 20th century, after a long pause, a brand new production of the cribs was started there. However, the craftsmen did not take up the previous tradition. Although several crib makers with their peculiar style work nowadays in Příbor and its environs, the
personality of Antonín Jařabáč is indispensable and dominant in
this respect. He was born in 1910 in a provincial milieu of the village of Klokočov near Příbor. The works of Antonín Jařabáč are chacterized especially by their handicraft values. Besides the figure and ornamental sculptures, it is possible to consider the crib making as a sort of peak of the carving self-fulfilment of Antonín Jařabáč. Even the other contemporary crib makers from Příbor take up the work of Antonín Jařabáč. Thus during a short period, there a specific group of people who may be designated, according to their territorial relevance, as the Příbor crib makers appeared handicraftsmen. However, Antonín Jařabáč remains for the local inhabitants the most significant representative of the present crib creators.
The structure of the group (\mathbb{Z}/n\mathbb{Z})* and Fermat’s little theorem are the basis for some of the best-known primality testing algorithms. Many related concepts arise: Euler’s totient function and Carmichael’s lambda function, Fermat pseudoprimes, Carmichael and cyclic numbers, Lehmer’s totient problem, Giuga’s conjecture, etc. In this paper, we present and study analogues to some of the previous concepts arising when we consider the underlying group G_{n}:=\left \{ a+bi\in \mathbb{Z}\left [ i\right ]:a^{2}+b^{2}\equiv 1\left ( mod n \right ) \right \}. In particular, we characterize Gaussian Carmichael numbers via a Korselt’s criterion and present their relation with Gaussian cyclic numbers. Finally, we present the relation between Gaussian Carmichael number and 1-Williams numbers for numbers n ≡ 3 (mod 4). There are also no known composite numbers less than 1018 in this family that are both pseudoprime to base 1 + 2i and 2-pseudoprime., José María Grau, Antonio M. Oller-Marcén, Manuel Rodríguez, Daniel Sadornil., and Obsahuje seznam literatury