Počátky studia fyziky plazmatu na Přírodovědecké fakultě Masarykovy univerzity v Brně jsou spjaty s osobností profesora Václava Trunečka (* 16. 11. 1919 - † 6. 7. 1997)., Jan Janča., and Obsahuje bibliografii
Norway spruce is a wide-spread food resource and its utilisable biomass exceeds the needs of herbivores. Needles seem to be a generally ignored food component in temperate forests that is consumed only when there are no better food sources. It is used especially during winters with deep snow cover. The aim of this study was to test presumption of needles as nutritive poor component of ungulate diets through botanical diet analyses and chemical nutrition estimation (content of crude protein and metabolizable energy volume in faeces) and elaborate the calibration curve on indirect estimation of quality food resources for ungulates in environment (NIRS needle content in faeces). High content of spruce needles corresponded well with a low quality winter diet of wild ungulates and may reflect animal nutritional constraints. As a consequence, the content of spruce needles may be used as an easy index of animal performance in a particular environment in forested area with coniferous forests in temperate zone. Needle content can be determined from the faeces by near infrared spectrophotometer and this easy technique can be recommended as indicator of the food resources quality for ungulates.
The photosynthetic activities of three planktonic desmid species (Staurastrum brachiatum, Staurodesmus cuspidatus var. curvatus, and Staurastrum chaetoceras) were compared after adaptation to medium enriched with either a 20 mM Na+-phosphate (P) or HEPES buffer. Incubations up to 2 d were carried out at pH 6 or 8 under normal air or air enriched with 5 % CO2. Gross maximum photosynthetic rate (Pmax) and growth rate were decreased in both S. brachiatum and Std. cuspidatus at higher pH when using the HEPES buffer and this effect was independent of CO2 concentration, indicating that pH had an inhibitory effect on photosynthesis and growth in these species. The P-buffer at pH 8 caused a large decrease in Pmax and quantum yield for charge separation in photosystem 2 (PS2), compared to HEPES-buffered algae. This effect was very large in both S. brachiatum and Std. cuspidatus, two species characteristic of soft water lakes, but also significant in S. chaetoceras, a species dominant in eutrophic, hard water lakes. The decreased Pmax in P-buffer could not be related to a significant increase in cellular P content known to be responsible for inhibition in isolated chloroplasts. Experiments at pH 6 and 8 showed that two conditions, high pH and high Na+ concentration, both contributed to the decreased Pmax and quantum yield in the desmids. Effects of a P-buffer were less pronounced by using K+-P buffer. The use of P-buffer at pH 8 possibly resulted in high irradiance stress in all species, indicated by damage in the PS2 core complex. In the soft water species pH 8 resulted in increased non-photochemical quenching together with a high de-epoxidation state of the xanthophyll cycle pigments. and E. Spijkerman ... [et al.].
The inotropic effects of insulin in the rat heart are still incompletely understood. In this study, the effects of insulin on cardiac contraction were studied in right ventricular papillary muscles from both control rats and rats with chronic diabetes (lasting 16 weeks). Diabetes was induced by the application of streptozotocin (STZ) and the development of diabetes was documented by increased levels of blood glucose, by reduction in body weight and by decreased plasma concentrations of insulin. The contraction was significantly smaller in diabetic rats. Insulin (80 IU/l) reduced the contraction force in both control and diabetic groups. The post-rest potentiation of contraction was not influenced by insulin in control rats, but insulin increased it in diabetic rats. The negative inotropic effect of insulin was preserved in the presence of cyclopiazonic acid (3 μmol/l), a blocker of sarcoplasmic reticulum (SR) Ca2+ pump, in both control and diabetic groups. In contrast, the negative inotropic effect of insulin was completely prevented in the presence of nifedipine (3 μmol/l), a blocker of L-type Ca2+ current. We conclude that insulin exerts a significant negative inotropic effect in rat myocardium, both control and diabetic. This effect is probably related to processes of SR Ca2+ release triggering, whereas SR Ca2+ loading is not involved.
V práci sa zavádzajú nehamiltonovské štatistické systémy klasických častíc, ktorých správanie je určené podmienenou pravdepodobnosťou rýchlosti a súradnice každej častice v závislosti na stave jej okolia. Na rozdiel od hamiltonovských systémov sa nezavádza Hamiltonián systému a jedinými zachovávajúcimi veličinami sú objem a počet častíc v systéme. Konštruujú sa mikrokanonické a kanonické súbory častíc vzhĺadom na zachovávajúci sa objem. Uvedený prístup sa aplikuje na systém vozidiel na jednosmernej ceste s jedným jazdným pruhom, opísaný pravdepodobnosťou rýchlostí áut ako funkce vzdialenosti a rýchlosti predchádzajúceho vozidla. Výpočty sa robia na jednorozmernej mriežke s diskrétnymi rýchlosťami vozidiel. Výsledkom výpočtu v mikrokanonickom súbore je pravdepodobnosť celkovej rýchlosti skupiny ako funkcie hustoty áut. V kanonickom súbore sa získali pravdepodobnosti fluktuácií celkovej dĺžky skupiny vozidiel ako časti veĺkého mikrokanonického súboru. Našli sa fázové prechody medzi voĺným tokom vozidiel a samovoĺne sa vytvárajúcou zápchou pri dostatočne účinných brzdách vozidiel. V opačnom prípade vznikajú kolóny vozidiel pohybujúce sa rovnakou, malou rýchlosťou., Antonín Šurda., and Obsahuje seznam literatury