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Dendrochronological dating of catastrophic slope movements
Tumajer, Jan ; Treml, Václav (advisor) ; Burda, Jan (referee)
Mass-movements are one example of natural processes that can pose a serious risk for human beings and their possessions. Dendrochronology, a method capable of their reconstruction, can provide parameters of former events, which can be used for planning protective measures. The possibilities for the application of dendrochronological methods have been tested by means of meta-analysis of electronic and printed scientific articles and a case study focused on former avalanche activity in Schustler's avalanche path (Labský důl, Krkonoše Mts.). The main conclusion of the first one is the clear spatial disproportion of the recent dendrogeomorphological research activities - e.g. the dating of avalanches is typical for mountains of Montana (USA); the Alpine region (mainly Switzerland), on the other hand, absolutely dominates in the research of debris-flows. In the case study, the analysis of material with well-chosen indicators led to high accuracy results comparable with the results of scientific articles focused on avalanches, and made the identification of 14 years (in the period 1953-2007) with potential avalanche acitvity possible. Although methods of dendrogeomorphology are usually neglected in the research of avalanches in the Czech republic, their great potential for future applications is shown....
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Intracranial Aneurysms - Treatment Options and Natural Course. Safety and Efficacy of Treatment Strategies for Posterior Inferior Cerebellar Artery Aneurysms.
Petr, Ondřej ; Beneš, Vladimír (advisor) ; Haninec, Pavel (referee) ; Přibáň, Vladimír (referee)
BACKGROUND: Posterior inferior cerebellar artery (PICA) aneurysms are an uncommon, heterogeneous group of aneurysms with poorer neurological outcomes compared to other intracranial aneurysms. At first, as part A, we conducted a systematic review of the literature to evaluate the safety and efficacy of treatment strategies for PICA-aneurysms. Subsequently, as part B, we performed a multicenter retrospective study to analyze the outcome in a large series of patients treated with contemporary microsurgical and endovascular techniques. METHODS: For the meta-analysis, a systematic search of Medline, EMBASE, Scopus and Web of Science was done for studies published through November 2015. We included studies that described treatment of PICA-aneurysms with ≥10 patients. Random-effects meta-analysis was used to pool the following outcomes: complete occlusion, technical success, periprocedural morbidity/mortality, stroke rates, aneurysm recurrence/rebleed, CN-palsies rates, and long-term neurological morbidity/mortality. As the second part, aiming to report the current trends and results in treatment strategies for PICA-aneurysms, records of 94 patients treated for PICA-aneurysms between 2000 and 2015 at 3 large referral neurovascular centers were retrospectively reviewed. RESULTS: In the meta-analysis, we...
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Does butterfly mating behaviour change with phenological condition of populations?
VLAŠÁNEK, Petr
The optimization theory assumes that males of insects with separate adult generations should preferentially invest into the mating if there are the most fresh females; in other times they should save energy and focus on maintenance activities. Based on this assumption, butterfly behaviour should change with season, population density (mainly the sex ratio) and day time. To explore these assumptions, we used mark recapture data obtained from several mark-recapture studies, which contained records of behaviour of each handled individual. In total, we analysed data on 14 species, 24 ``butterfly-seasons{\crqq}, 21 737 individuals (14 228 males, 7 509 females). We subjected the behavioural data to ordination analyses controlled for weather effects. For daily patterns, morning and afternoon activities comprise mainly of maintenance activities, while mating seems to occur in middays. Regarding seasonal patterns, males of most of the species switched from mating behaviour to maintenance behaviour. No prevailing trend applied to females, in which we found both transitions from mating behaviour to maintenance activities and opposite patterns. Density predictors (sex ration, daily population size) revealed changes in mating behaviour of one sex with changing the abundance of the other sex. In conclusion, exploring mark-recapture data for behavioural patterns proved to be fruitful, but cannot fully replace studying behaviour via more traditional ethological methods.
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