Former authors claimed that, due to parasites' aggregated distribution, small samples underestimate the true population mean abundance. Here we show that this claim is false or true, depending on what is meant by 'underestimate' or, mathematically speaking, how we define 'bias'. The 'how often' and 'on average' views lead to different conclusions because sample mean abundance itself exhibits an aggregated distribution: most often it falls slightly below the true population mean, while sometimes greatly exceeds it. Since the several small negative deviations are compensated by a few greater positive ones, the average of sample means approximates the true population mean., Jenő Reiczigel, Lajos Rózsa., and Obsahuje bibliografii
Parasitic plants growing on tree branches may be a novel niche and phytoresource for arthropods. The spatial continuity between hosts and their parasites in canopies might provide a homogeneous environment for arthropod communities, but differences in mistletoe leaves and host needles could be exploited by different species of arthropods. Therefore, it is important to determine insect-community assemblages in order to discover the role of parasitic plants as a different habitat for arthropods. Thus, we aim to evaluate the level of similarity between the arthropod community on mistletoe (Viscum album) and that on its two principal pine hosts, Black pine (Pinus nigra) and Scots pine (P. sylvestris), on a Mediterranean mountain. Our results reveal that, irrespective of the species of pine host, V. album has a stable, independent and simple arthropod trophic web, composed mainly of two specialist hemipteran herbivores, Cacopsylla visci (Psyllidae) and Pinalitus viscicola (Miridae), and a hemipteran predator, Anthocoris visci (Anthocoridae). Despite this, the composition of the arthropod communities differed significantly on both host species, with a greater richness and diversity on Scots than Black pine and these differences are not reflected in the community on mistletoe. Overall, we conclude that, although Viscum album is considered to be a pest of pine, its presence increases the heterogeneity of the forest canopy by providing a novel habitat for a new and specific community of arthropods. In addition, this is a new record for and most probably an extension of the southernmost limit of the known geographical distribution of the arthropod community inhabiting V. album., Alba Lázaro-González, José A. Hódar, Regino Zamora., and Obsahuje bibliografii
The aim of this study was to ascertain the persistence of heart rate and blood pressure oscillations at the onset of voluntary apnea in humans and to assess the dependence of the fluctuations` parameters on the chemoreceptor activity. In 24 young subjects (10 males, 14 females, mean age 20.4 years) heart rate (represented by its reciprocal value - RR-intervals), systolic blood pressure (SBP) and diastolic blood pressure (DBP) during controlled breathing (CB) of atmospheric air and oxygen followed by apnea were recorded continuously. The cosine functions were then fitted by nonlinear regression analysis to the heart rate, SBP and DBP oscillations during CB and at the onset of apnea. The parameters of oscillations were different during atmospheric air breathing compared to oxygen breathing. During oxygen breathing there was an increase of the RR-interval oscillations - relative bradycardia and enhanced magnitude of respiratory sinus arythmia. During apnea, the base level of the blood pressure oscillations was higher after breathing of atmospheric air compared o oxygen breathing. At least one cosine-like wave oscillation was present at the onset of apnea in the heart rate, SBP and DBP and the second wave was present in all assessed parameters in at least 70 % of recordings. The oscillations in RR-intervals are, to some extent, independent of blood pressure oscillations. No significant gender differences were found either in the duration of breath holding or in the RR and SBP oscillations parameters., M. Javorka, I. Žila, K. Javorka, A. Čalkovská., and Obsahuje bibliografii
The American astronaut, Andrew Feustel, who took "Krtek" (the Little Mole), the cartoon character created by the Czech animator Zdeněk Miler, into space with him aboard the Endeavour space shuttle last May, completed a visit to the Czech Republic during which he promoted science and technology among young Czechs. The Academy of Sciences of the Czech Republic, which invited Feustel to Prague, awarded him the Honorary Medal "De Scientia Et Humanitate Optime Meritis" for propagating science and research. He is the third American astronatu, after John Blaha and Eugene Cernan, to have a Czech connection, his wife Indira's mother, having been born in Znojmo. This was the second time Feustel took something "Czech" with him into space. On his first mission in May 2009, he brought along a book of poems entitled Cosmic Songs by the Czech writer Jan Neruda. and Luděk Svoboda.
Z geobotanického hlediska je popsána subalpinská a alpinská vegetace v horách jihovýchodní Brazílie. Přirozené požáry tam ovlivňují strukturu rostlinných společenstev. Jsou zmíněny zajímavé životní způsoby, jako je mykorhiza, hemiparazitismus a masožravost. Jedním z nejzajímavějších fenomenů je symbióza mezi masožravou rostlinou Utricularia cornigera (bublinatkou růžkatou) a růžicovitými rostlinami Vriesea atra nebo Eryngium fluminense. Je diskutováno o problému srovnávání popsané brazilské vegetace a páramos v Andách. Pojem "brazilská páromos" je odmítnut., The subalpine and alpine vegetation in mountains of south-eastern Brazil is described from the botanical point of view. Natural fires affect the structure of plant communities there. Interesting life strategies, such as mycorrhiza, hemiparasitism and carnivory, are mentioned. One of the most interesting is the symbiosis between carnivorous Utricularia cornigera and rosette plants of Vriesea atra or Eryngium fluminense. Brazilian vegetation and páramos in the Andes are compared., and Miloslav Studnička.
a1_ Tématem článku jsou vztahy mezi Nicolae Ceauşeskem (1918-1989), generálním tajemníkem Rumunské komunistické strany (Partidul Comunist Român) a předsedou Státní rady Rumunské socialistické republiky, a Josipem Brozem Titem (1892-1980), předsedou Svazu komunistů Jugoslávie (Savez komunista Jugoslavije) a prezidentem Socialistické federativní republiky Jugoslávie, tak jak se vyvíjely v politické rovině v letech 1966 až 1969, tedy v době, kdy vrcholilo a posléze bylo potlačeno reformněkomunistické hnutí v Československu. Analýza rumunského historika těží především z nedávno zpřístupněných dokumentů v rumunských centrálních archivech referujících o pěti schůzkách mezi oběma státníky v uvedeném období. Autor nastiňuje vztahy Rumunska a Jugoslávie od padesátých let minulého století a charakterizuje jejich pozici v rámci mezinárodního komunistického hnutí, která byla také hlavním tématem rozhovorů Tita s Ceauşeskem. V zájmu obou vůdců bylo udržet si větší manévrovací volnost, kterou se jim podařilo vydobýt vůči Sovětskému svazu, a zabránit upevnění jeho dominance v „socialistickém táboře“, kterou se zejména Rumuni snažili vyvažovat přátelskými vztahy s Čínskou lidovou republikou. Vzájemný vztah Tita a Ceauşeska líčí autor jako založený na důvěře, jež vycházela ze sbližování společných zájmů a umožňovala koordinovat zahraničněpolitické postoje i překonávat dílčí neshody. Toto strategické partnerství se projevilo i v otevřené jugoslávské a rumunské podpoře pražského jara, jak ji nejnápadněji deklarovaly návštěvy obou státníků v Praze vpředvečer vojenské intervence pod vedením Sovětů do Československa, a poté v odmítavém postoji vůči tomuto násilnému aktu., a2_Srpnovou okupací Československa se Tito, a zvláště Ceauşescu cítili přímo ohroženi a konzultovali spolu možnosti, jak předejít nebo čelit eventuální sovětské invazi do jejich zemí. Autor přitom připisuje Titovi zásadní vliv na proměnu Ceauşeskovy rétoriky od konfrontačního veřejného odsouzení okupace po pragmatické potvrzení loajality ke Kremlu. Oba státníci poté volili cestu zdrženlivosti a snahy o zlepšení vztahů se Sověty, aniž by změnili svůj nesouhlas s okupací a odpor k sovětské hegemonii. Nejodhodlanějším gestem vzdoru Nicolae Ceauşeska bylo přijetí amerického prezidenta Richarda Nixona v srpnu 1969 v Bukurešti., b1_The article is concerned with the relations between Nicolae Ceauşescu (1918-1989), the General Secretary of the Romanian Communist Party and Chairman of the State Council of the Romanian Socialist Republic and, on the other side, Josip Broz Tito (1892-1980), the Chairman of the Union of Communists of Yugoslavia and President of the Socialist Federative Republic of Yugoslavia, as they developed at the political level from 1966 to 1969, when the reform Communist movement in Czechoslovakia was coming to a peak and was soon crushed. This analysis by a Romanian historian draws mainly on records recently made accessible in central Romanian archives, which relate to the five meetings between these two senior politicians in this period. The author outlines Romanian-Yugoslav relations from the 1950s onwards, and discusses their place in the international Communist movement, which was also the main subject of the talks between Tito and Ceauşescu. It was in the interest of the two leaders to maintain the greater room for manoeuvre which they won from the Soviet Union. That was supposed to prevent the buttressing of Soviet dominance in the ‘Socialist camp’, which the Romanians in particular tried to use to compensate for friendly relations with the People’s Republic of China. The author argues that the mutual relations between Tito and Ceauşescu were based on trust and stemmed from the identification of common interests, which enabled them to coordinate foreign-policy positions and surmount particular disagreements. This strategic partnership was also manifested in the open Yugoslav and Romanian support for the Prague Spring, the most striking declarations of which were the two Prague visits by the two heads of state on the eve of the Soviet-led military intervention in Czechoslovakia, and afterwards in their negative positions on the act of aggression., b2_Tito and particularly Ceauşescu saw the August occupation of Czechoslovakia as a direct threat to their own security, and they consulted each other about possible ways to avoid, or face, eventual Soviet military intervention in their own countries. The author attributes considerable influence to Tito in changing Ceauşescu’s rhetoric from a confrontational public condemnation of the occupation to a pragmatic confirmation of loyalty to the Kremlin. The two heads of state henceforth chose a path of restraint and sought to improve relations with the Soviets, without abandoning their disagreement over the occupation or their resistance to Soviet hegemony. Ceauşescu’s most resolute gesture of resistance was to welcome the US President, Richard Nixon, to Bucharest in August 1969., Cezar Stanciu ; z angličtiny přeložila Marzia Patonová., and Obsahuje bibliografii