Pátý rok asistentské praxe na Pedagogické fakultě JU v Českých Budějovicích

Asistentská praxe studentů učitelství je volitelnou disciplínou, která je ve studijním programu na PF JU v Českých Budějovicích oficiálně nabízena od roku 2000. Student při této praxi působí jako atypický učitel; pomáhá učiteli se zabezpečením výuky a podílí se na řízení vyučování. Učitelé za tento typ praxe nejsou honorováni, proto je její realizace závislá na dohodě studenta s učitelem školy. Učitelovou odměnou je studentova pomoc. V roce 2000 si zvolilo asistentskou praxi 28 studentů, v roce 2005 to bylo již 176 studentů

Tubulin response to intense nanosecond-scale electric field in molecular dynamics simulation

Intense pulsed electric fields are known to act at the cell membrane level and are already being exploited in biomedical and biotechnological applications. However, it is not clear if electric pulses within biomedically-attainable parameters could directly influence intra-cellular components such as cytoskeletal proteins. If so, a molecular mechanism of action could be uncovered for therapeutic applications of such electric fields. To help clarify this question, we first identified that a tubulin heterodimer is a natural biological target for intense electric fields due to its exceptional electric properties and crucial roles played in cell division. Using molecular dynamics simulations, we then demonstrated that an intense - yet experimentally attainable - electric field of nanosecond duration can affect the bβ-tubulin’s C-terminus conformations and also influence local electrostatic properties at the GTPase as well as the binding sites of major tubulin drugs site. Our results suggest that intense nanosecond electric pulses could be used for physical modulation of microtubule dynamics. Since a nanosecond pulsed electric field can penetrate the tissues and cellular membranes due to its broadband spectrum, our results are also potentially significant for the development of new therapeutic protocols

Evolution of avalanche conducting states in electrorheological liquids

Charge transport in electrorheological fluids is studied experimentally under strongly nonequlibrium conditions. By injecting an electrical current into a suspension of conducting nanoparticles we are able to initiate a process of self-organization which leads, in certain cases, to formation of a stable pattern which consists of continuous conducting chains of particles. The evolution of the dissipative state in such system is a complex process. It starts as an avalanche process characterized by nucleation, growth, and thermal destruction of such dissipative elements as continuous conducting chains of particles as well as electroconvective vortices. A power-law distribution of avalanche sizes and durations, observed at this stage of the evolution, indicates that the system is in a self-organized critical state. A sharp transition into an avalanche-free state with a stable pattern of conducting chains is observed when the power dissipated in the fluid reaches its maximum. We propose a simple evolution model which obeys the maximum power condition and also shows a power-law distribution of the avalanche sizes.Comment: 15 pages, 6 figure

Review of invasive grapevine aphid, Aphis illinoisensis Shimer, and native parasitoids in the Mediterranean (Hemiptera, Aphididae; Hymenoptera, Braconidae, Aphidiinae)

A summary of the study of Aphis illinoisensis Shimer on grapes, Vitis vinifera in the Mediterranean area brings references and new findings on its distribution in Crete/Greece, Turkey, Northern Cyprus, Malta, Israel, Montenegro, Tunisia, Algeria and Libya. Parasitoids of A. illinoisensis were only occasionally found (Aphidius matricariae Hal. - Cyprus, Turkey, Greece; Aphidius colemani Viereck - Libya; Lysiphlebus testaceipes Cress. - Algeria). Of the native species, i.e. A. colemani, and others similar to the native species, L. testaceipes seem to be a promising biocontrol agent within the framework of an ecologically friendly management in the area. Given the evidence of its expansion, A. illinoisensis is expected to expand further in several directions from the recently documented invaded area to all the grape-growing areas of the Mediterranean and even those of South-Eastern and Central Europe

The response of Plantago major ssp pleiosperma to elevated CO2 is modulated by the formation of secondary shoots

The effect of elevated CO2 on the relative growth rate (RGR) of Plantago major ssp. pleiosperma was studied during the vegetative stage, in relation to plant development, by growing plants at 350 mu l l(-1) or at 700 mu l l(-1) CO2 in non-limiting nutrient solution with nitrate. To minimize interference by the accumulation of non-structural carbohydrates in the interpretation of results, RGR was expressed on a f. wt basis (RGR(FW)), as were all plant weight ratios. Stimulation of the RGR(FW) Of the whole plant by elevated CO2 was transient, and did not last longer than 8 d. At the same time a transient increase in root weight ratio (RWR) was observed. In order to investigate whether the transient effect of elevated CO2 on RGR(FW) was size-dependent, the data were plotted versus total f. wt (log(e) transformed). The transient period of stimulation of RGR(FW) and of RWR by elevated CO2 was still found, but in both CO2 treatments RGR(FW) decreased after a certain plant size had been reached. This size coincided with the stage at which secondary shoots started to develop, and was reached earlier in plants grown at elevated CO2. The RGR of these secondary shoots (RGR(see)) was Still increased when the period of whole plant stimulation of RGR(FW) had ended, indicating that the development of these new sinks took priority over a continuation of the stimulation of RWR. It is hypothesized that in this Plantago subspecies the response of the RGR(FW) of the whole plants to elevated CO2 is modulated by the formation of secondary shoots. Apparently, partitioning of the extra soluble carbohydrates at elevated CO2 to this tissue takes precedence over partitioning to the roots. resulting in a cessation of stimulation of plant RGR(FW) by elevated CO2.info:eu-repo/semantics/publishedVersio