Termodynamika se zabývá dvěma odlišnými a na první pohled nesouvisejícími oblastmi fyziky. Na jedné straně zkoumá otázku účinnosti tepelných a chladicích strojů. Na straně druhé se snaží identifikovat obecné podmínky rovnováhy systému mnoha částic. Jak mohou být dva tak odlišné obory propojeny? Důvod je následující. "Kdekoliv a kdykoliv existuje rozdíl teplot, lze jej využít ke konání práce." (Sadi Carnot) V příspěvku se pokusíme naznačit abstraktní logickou výstavbu termodynamiky a dokumentovat zásadu: "S dobrými přáteli nikdy nediskutuj o politice, o náboženství a o termodynamice." and Petr Chvosta.
International Thermonuclear Experimental Reactor ITER (mezinárodní experimentální termojaderný reaktor) je dalším krokem na cestě k termojaderné elektrárně.
V termojaderné elektrárně se má energie získávat - podobně jako je tomu u procesů na Slunci - slučováním (fúzí) lehkých atomových jader. Ze všech možných fúzních reakcí, které by pro takovouto elektrárnu přicházely v úvahu, skýtá reakce mezi izotopy vodíku deuteriem a tritiem největší energetickou výtěžnost při nejnižší teplotě. "Termojaderný reaktor" Slunce využívá normálního vodíku, který drží pohromadě jako horké plazma vlastní tíhou. Naproti tomu v pozemských podmínkách se musí palivová směs udržovat v pasti magnetického pole a být takto držena mimo stěny vakuové nádoby. Výhody termojaderné energie jsou známé: vysoká mezní bezpečnost, téměř neomezené zásoby paliva, žádné emise a malé množství radioaktivního odpadu. Jak daleko došel v posledních letech výzkum termojaderné reakce a jak dlouho bude ještě trvat, než se stane tento energetický zdroj přínosem, který termojaderní výzkumníci očekávají pro zásobování elekřinou, to jsou nejdůležitější témata tohoto článku. and Hans-Stephan Bosch, Alexander Bradshaw ; přeložili překladatelský servis Skřivánek a Karel Rohlena.
The water structures Hričov - Mikšová - Považská Bystrica are a group of channel hydro power plants (HPP) on the Váh Cascade. Modelling methods verified on other channel hydro power plants are easily applicable in their case. In 2006 were by our department provided terrain measurements and hydraulic research on these water structure systems. The results of measurements were used for the better calibration of hydro dynamical model of these power plants. The presented paper describes this process. This work was supported by Science and Technology Assistance Agency under the contract No. APVT-20-046302.
We studied the association between environmental variables and the terrestrial habitat use by adults of the burrowing toad Rhinella fernandezae in Buenos Aires, Argentina. We assessed the cover type, height of vegetation, soil moisture and hardness. We compared these habitat variables in quadrats where toads were present along a transect (n = 30 quadrats, 19 with toad burrows) with respect to randomly chosen quadrats (n = 17). We found that R. fernandezae does not use the habitat at random, and that habitat variables that mostly infl uenced its habitat use were soil hardness after raining, probably because it facilitates the construction of burrows, and broad-leaved plant cover, which may be affecting toads indirectly through other habitat variables, such as shadowing, air moisture and refuge from predators.
This article is concerned with the memory and commemoration of acts of armed force which were committed as part of the civilian resistance to the Communist régime in its ‘founding period’ after February 1948. It focuses on how memory is constituted around this minority form of anti-Communist resistance, particularly by means of memorial sites in the process of their formation in the period before the Changes that began in mid-November 1989 and also afterwards. In the fi rst part of the article, the author looks at armed confl icts at the edge of the Iron Curtain, that is, on the western borders of Communist Czechoslovakia. She seeks to demonstrate that the way of looking at border crossings by people fl eeing to the West is still considerably infl uenced by the memory and commemorative activities of veterans of the former border guards, amongst whom dominates the image of these refugees as internal enemies of the State. The second part of the article isdevoted to instances of so-called ''political murder'', that is, acts of violence against Communist politicians, which are connected particularly with villages. Most of these stories are gradually being forgotten; society does not want to recall them. An exception, however, is the memory of the sad events in the village of Babice, in the Bohemian-Moravian uplands, in 1951, which has repeatedly been used by politicians. In the third part of the article, the author considers the social discourse about the ethical dimension of armed anti-Communist resistance, which is almost exclusively focused on the atypical case of the group led by the Mašín brothers, and the process of forming the memory of the three resistances (the fi rst, against Austria-Hungary during the Great War; the second, against the German occupying forces during the Second World War; and the third, against the Communist régime during the Cold War). She describes the commemorative activities of the Confederation of Political Prisoners as part of the strategy to bolster the social standing of the third, anti-Communist resistance, and she points to certain analogies between the unchallenged memories of political prisoners and the memories of the former border guards in contemporary historiography. and Překlad: Lucia Faltinova
Sensitivity of various mitochondrial enzymes to oxidative damage was tested on isolated rat liver hepatocytes
permeabilized by digitonin. In permeabilized hepatocytes
normal respiratory control
values were obtained and
mitochondrial membranes remained intact. Respiratory rate
s of NADH-dependent (glutamate+malate, palmitylcarnitine
+ malate) and flavoprotein-dependent (succinate) substrates were determined in hepatocytes exposed for 5 min to
0.5-3 mM
tert
-butyl hydroperoxide before addition of digitonin.
Our data showed that oxidation of NADH-dependent
substrates is much more sensitive to oxidative stress than ox
idation of flavoprotein-dependent ones, evidently due to the
modification of iron-sulfur clusters or SH groups in the NADH dehydrogenase enzyme complex (Complex I).
The Alpine Longicorn (Rosalia alpina) is an endangered and strictly protected icon of saproxylic biodiversity. Here we present an overview of its distribution in the Czech Republic, its host plants, and habitat requirements. We also comment upon the forestry and conservation management of its last inhabited sites. and Lukáš Drag a kol.