In July 2015, the 46th International Physics Olympiad was held in Mumbai, the capital city of the Indian state, Maharashtra. Members of the Czech team obtained three silver medals and two bronze medals. In addition, the Slovak team won one silver and three bronze medals. In this article a theoretical task set during the competition is presented, which deals with calculations of a nuclear fission reactor. and Filip Studnička, Jan Kříž, Ľubomír Konrád, Bohumil Vybíral.
Jednou, krátce před půlnocí, tížen příslibem redakci Československého časopisu pro fyziku, nechávám běžné práce, otevřu Word a po nadpisu mě napadne podívat se do kalendáře: opravdu, za chvíli začíná 19. říjen 2010. Právě před 100 lety, 19-10-1910 (tak sám rád psal), se narodil Subrahmanyan Chandrasekhar, velká postava vědy 20. století, jeden z nejuniverzálnějších astrofyziků, nositel Nobelovy ceny za fyzku v roce 1983, ve vědeckých kruzích známý jako Chandra. O fyzikálním a astronomickém významu jeho Nobelovy ceny, kterou získal společně s W. A. Fowlerem, jsem již v tomto časopisu psal [1]. V následujícím se chci více zaměřit na události a postavy v okolí jeho světočáry; přitom čerpám především z podrobné biografie [2]. Na závěr připojím několik osobních vzpomínek na interakci s ním, nebudu však již opakovat ty, které jsou uvedeny v článku psaném před 27 lety., Jiří Bičák., and Obsahuje bibliografii
The short war waged in the autumn of 1962 between India and China for disputed territory in High Himalayas had a long-term devasting effect on the relations between the two Asian powers. The present first part of a study recapitulating the genesis of the dispute and subsequent road to military confrontation maps the origins of the problem in the colonial period of Indian history, with particular focus on changes in British cdecision making in the evolving international context. The one-sided furthering of territorial claims in the absence of a strong and determined adversary led, paradoxically, to parallel exdistence of several alternative frontier lines with no fixed and clearly demarcated border in existence along the extended Indo-Tibetan boundary. The second instalment will follow the developments in the dramatically changed conditions after the emergence in the 1950s of India and China as two strong independent nations., Jaroslav Strnad., and Obsahuje bibliografii
The new power configuration that emerged in the regions of South and East Asia in the wake of World War II and the following decolonization process introduced new players to the game of international politics; the roles played by them were orten inherited from the actors of the previous era. it was the general framework of the bipolar world system and the Cold War that represented a new element in traditional rivalries, and which had the capacity to exacerbate problems that had previously lain dormant. The genesis and escalation of the India-china border dispute, interconnected with the status of Tibet, which was viewed by China as part of her own territory and contemplated by India as a semi-independent buffer state, serves as a classic example. On the Indian side, the problem was further aggravated by the inability of the government to coordinate and fully control the activities of its iontelligence. The article follows the gradual development of the ambiguous approach of Indian foreign policy toward its northern neighbour and the silent Indian acquiescence of the involvement of the United States in the Tibetan issue up to the first bloody border clashes in 1959., Jaroslav Strnad., and Obsahuje bibliografii
We investigated the lead (Pb) effect on chlorophyll (Chl) fluorescence and photosynthetic electron transport system in Talinum triangulare (Jacq.) Willd. Plants were exposed to different concentrations of Pb(NO3)2 (i.e. 0, 0.25, 0.5, 0.75, 1.0, and 1.25 mM) for seven days in hydroponic experiments. Pb-treated leaves exhibited a relative decrease in Chl fluorescence induction curve, which resulted in the decrease of maximal fluorescence yield, maximal quantum yield, and effective quantum yield of PSII, while nonphotochemical quenching, quantum yield of regulated and nonregulated energy dissipation of PSII significantly increased during Pb stress. Furthermore, Pb concentrations also caused a decrease in maximal P700 change, photochemical quantum yield, nonphotochemical quantum yield, and ETR of PSI. We suggested that the changes in these parameters were a manifestation of Pb interference in the electron transport chain in both PSII and PSI. The sensitivity of PSII was greater than that of PSI in T. triangulare leaves., A. Kumar, M. N. V. Prasad., and Obsahuje bibliografii
In the present study, the physiological efficiencies of 181 mini-core peanut accessions (genotypes) were evaluated according to variability in their physiological performance in the field during summer (2012). Genotypes were categorized into groups of high, medium, and low physiological activity. Thirty-four genotypes showed high net photosynthetic rate (PN > 33 μmol m-2 s-1), 28 genotypes exhibited high stomatal conductance (gs > 0.54 mmol m-2 s-1), 33 genotypes manifested high transpiration rate (E > 11.8 mmol m-2 s-1), 30 genotypes performed with high water-use efficiency (WUE > 3.8), 30 genotypes reached high chlorophyll SPAD values (SCMR > 40), and 35 genotypes showed high maximum quantum yield of PSII (Fv/Fm > 0.86). In addition, few genotypes showed high values for multiple physiological traits. A total of 54 genotypes exhibited higher values in two, 20 genotypes showed a high value in three, and in eight genotypes, high values occurred in four different physiological traits. Interestingly, only two genotypes, NRCG 14493 and 14507, showed high values for five different traits. Positive correlation was observed between gs and PN, E, and gs, and between PN and Fv/Fm, while WUE and E showed a negative correlation. The genotypes with high PN, gs, and WUE coupled with high SCMR and Fv/Fm could be used in peanut crop improvement programme for yield enhancement as well as stress tolerance., A. L. Singh, R. N. Nakar, K. Chakraborty, K. A. Kalariya., and Obsahuje bibliografii