Luminiscence (u kovů se častěji hovoří o fotonové emisi) buzená hrotem rastrujícího tunelovacího mikroskopu (STM) kombinuje výhody STM mikroskopu s výhodami optických emisních metod. Hlavním problémem metody je však malý luminiscenční signál. Při tunelujících proudech v řádu jednotek nA je u materiálů s největší kvatovou účinností přeměny elektronů na fotony emitováno do plného prostorového úhlu maximálně ~107 fotonů/s. Velká pozornost proto musí být věnována sběrnému systému fotonů: je zapotřebí maximalizovat prostorový úhel sběru současně s minimalizací ztrát a šumu v detekčním řetězci., Petr Fojtík, Tomáš Mates, Antonín Fejfar, Jan Kočka, Ivan Pelant, Antonín Svoboda., and Obsahuje seznam literatury
The proces of solar eurge formation is atudied by means of computer simulations on the basis of a two-dimensional MHD model. It is assumed in the model that a small-scale magnetic field is penetrating in a compressible plasma medium with physical parameters near to those of the lower chromosphere. Computer simulations show that nonlinear effects lead to formation of relatively denser and hotter structures. This phenomenon is discussed as a link unifying the magnetic and nonmagnetic
mechanisms of surge formation proposed by various authors.
In field grown cashew trees {Anacardium occidentale L.) net photosynthetic rate (Pn) was maximum in leaves grown in all four directions (East - E, West - W, South - S and North - N) between 11 to 12 h. Between 15 to 16 h, photosynthetically active radiation (PAR) and were higher in W than in other directions, however stomatal conductance (g^) and transpiration rate (E) were similar in all the four directions. Maximum was found in the leaves of middle portion of the tree. Irradiance was more important for than gs, intercellular CO2 (Q), and E which did not exeit significant differences at different directions and timings.
Water-borne transmission of the coccidium Cryptosporidium parvum Tyzzer, 1912 is frequently responsible for outbreaks of human cryptosporidiosis. One of the most important was reported in 1993 in Milwaukee in the United States, where 403,000 cases were recorded. The determination of the percentage of oocysts excystated is the first step in evaluating their viability, but it alone is not sufficient. This percentage depended on the conditions of storage and also the presence of oxidant or disinfectent agents in water. The percentage of excystation is not always related to viability. Therefore, determination of the viability of excysted sporozoites by determining their infectivity for enterocytic Caco2 cell lines in culture provides information essential for evaluating the risk of contaminated drinking water.