A previously reported procedure for the introduction of Borrelia spirochetes into tick larvae by immersion in a suspension of spirochetes was tested on Ixodes ricinus (L.) ticks and three of the most medically important European Borrelia genomic species, B. burgdorferi sensu stricto, B. garinii and B. afzelii. The procedure was compared with ''classical'' infection of nymphs by feeding on infected mice. Both methods yielded comparable results (infection rate 44-65%) with the exception of B. afzelii, which produced better results using the immersion method (44%) compared with feeding on infected mice (16%). Nymphs infected by the immersion method at the larval stage were able to transmit the infection to naïve mice as shown by serology and PCR detection of spirochetal DNA in organs. The immersion method is faster than feeding on infected mice and provides more reproducible conditions for infection. It can be exploited for studies on both pathogen transmission and Borrelia-vector interactions.
The aim of our study was to develop a model producing obese mice in early adulthood (4-6 weeks) based on their over-nutrition during fetal and early postnatal development. The fertilized dams of the parental generation were fed the standard diet supplemented with high-energy nutritional product Ensure Plus during gestation and lactation. De livered weanlings were then fed with standard or supplemented diet and assessed for body fat deposits using EchoMRI at the ti me of early and late adulthood. Maternal over-feeding during th e period before weaning had the most significant effect on obesity development in the filial generation. In weanlings, signific antly higher body fat deposits and average body weight were recorded. Later, further significant increase in percentage of body fat in both male and female mice was observed. Withdrawal of the Ensure Plus supplement caused a decrease in the percentage of body fat in part of the filial generation. In offspring fed the standard diet, higher fat deposits persisted till the time of late adulthood. We conclude that this diet-induced obesity model might be used in exploration of the effects of elevated body fat on physiological functions of various organ systems during juvenile and early adulthood periods of life of a human being., J. Kubandová ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
This paper focuses on a two-layer approach to genetic programming algorithm and the improvement of the training process using ensemble learning. Inspired by the performance leap of deep neural networks, the idea of a multilayered approach to genetic programming is proposed to start with two-layered genetic programming. The goal of the paper was to design and implement a twolayer genetic programming algorithm, test its behaviour in the context of symbolic regression on several basic test cases, to reveal the potential to improve the learning process of genetic programming and increase the accuracy of the resulting models. The algorithm works in two layers. In the first layer, it searches for appropriate sub-models describing each segment of the data. In the second layer, it searches for the final model as a non-linear combination of these sub-models. Two-layer genetic programming coupled with ensemble learning techniques on the experiments performed showed the potential for improving the performance of genetic programming.
The purpose of the paper is to present existing and discuss modified optimization models and solution techniques which are suitable for engineering decision-making problems containing random elements with emphasis on two decision stages. The developed aproach is called two-stage stochastic programming and the paper links motivation, applicability, theoretical remarks, transformations, input data generation techniques, and selected decomposition algorithms for generalized class of engineering problems. The considered techniques have been found applicable by the experience of the authors in various areas of engineering problems. They have been applied to engineering design problems involving constraints based on differential equations to achieve reliable solutions. They have served for technological process control e.g. in melting, casting, and sustainable energy production. They have been used for industrial production technologies involving related logistics, as e.g. fixed interval scheduling under uncertainty. The paper originally introduces several recent improvements in the linked parts and it focuses on the unified two-stage stochastic programming approach to engineering problems in general. It utilizes authentic experience and ideas obtained in certain application areas and advises their fruitful utilization for other cases. The paper follows the paper published in 2000 which deals with the applicability of static stochastic programs to engineering design problems. Therefore, it refers to the basic concepts and notation introduced there and reviews only the principal ideas in the beginning. Then. it focuses on motivation of recourse concepts and two decision stages from engineering point of view. The principal models are introduced and selected theoretical features are reviewed. They are also accompanied by the discussion about difficulties caused by real-world cases. Scenario-based approach is detailed as the important one for the solution of engineering problems, discussion in data input generation is added together with model transformation remarks. Robust algorithms suitable for engineering problems involving nonlinearities and integer variable are selected and scenario-based decomposition is preferred. An original experience with using heuristics is shared. Several postprocessing remarks are added at the end of the paper, which is followed by an extensive literature review. and Obsahuje seznam literatury
Při analýze pohřebiště ze starší doby bronzové ve Vliněvsi (střední Čechy, okr. Mělník) byla zkoumána variabilita typů milodarů v hrobech různého pohlaví a věku. Krom jiného se ukázalo téměř výhradní zastoupení tyčinkových náramků v dětských hrobech. Rozborem všech dostupných nálezů tyčinkových náramků v hrobech únětické kultury v Čechách se tato vazba ukázala jako nenáhodná. Autoři diskutují hypotézu o spojení náramků s obdobím nedospělosti a s ním souvisejícími přechodovými rituály, případně ochrannou funkci těchto předmětů. and During an analysis of the Early Bronze Age burial site in Vliněves (central Bohemia, Mělník district), the variability of types of goods in graves of different sex and age was examined. Among other things, the study showed an almost exclusive representation of bar bracelets in the graves of juvenile individuals. An analysis of all available bar bracelet finds in Únětice culture graves in Bohemia suggested that this connection was not random. The authors discuss the hypothesis of the connection of the bracelets with the period of adolescence and related rites of passage, possibly the protective function of these artefacts.
Anthers, pistils and evolution (The evolution of reproduction systems in angiosperms). The reproduction systems in flowering plants are very diverse, most likely owing to sessile life way of plants. Without he possibility to move, search for the partner to reproduce becomes difficult, insect transfers pollen from one plant individual to another, which led to co-evolution of both flowering plants and their pollinators. The prevailing reproduction system in angiosperms is a hermaphroditism. The presence of both male and female organs in the same flower may results in self-crossing and increased risk inbreeding. Thus, plants evolved several mechanisms to avoid self-pollination. One of them is pollen self-incompatibility, which causes suppression of pollen gernmination on the stigma of the same genotype. After loss of self-incompatibility, some species developed a specific reproduction system called gynodioecy. It is characteristic by a co-occurrence of females and hermaphrodites in the same population. Females produce outbred progeny, whereas hermaphrodites ensure reproduction if the partner plants are not accesible. Dionecy, the reproduction system with females and males, widespread in animals, also occurs in plants, but with much lower frequency.
Týden s aplikovanou fyzikou FYKOSu je, jak název napovídá, týden, v jehož průběhu je snahou přiblížit středoškolákům jak aplikovanou fyziku a techniku ve výrobě, tak navštívit nějaká vědecká centra světové úrovně. Článek přináší reportáž z pohledu účastníka akce., Daniel Pitoňák, Karel Kolář., and Obsahuje bibliografii
Týden s aplikovanou fyzikou (zkráceně TSAF) [1] je akcí pořádanou MFF UK primárně pro středoškoláky se zájmem o fyziku. Její účastníci v roce 2014 navštívili dvě významná německá centra základního i aplikovaného výzkumu ve fyzice a jejích hraničních oborech, a to hamburský DESY a pak ASDEX Upgrade v Garchingu u Mnichova. Článek informuje čtenáře o průběhu této akce, která může být silným motivačním motorem pro další studium fyziky., Dominika Kalasová, Karel Kolář., and Obsahuje bibliografii
Celkem 20 středoškoláků ze všech koutů České i Slovenské republiky se zúčastnilo Týdne s aplikovanou fyzikou. Studenti měli v průběhu sedmi dní možnost dozvědět se spoustu nových informací a navštívit zajímavá experimentální pracoviště v Praze a okolí. and Pavla Rudolfová.