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39792. Urushiol, yperit z přírody
- Creator:
- Patočka, JIří and Frynta, Josef
- Type:
- article, model:article, and TEXT
- Language:
- Czech
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
39793. Urychlovač a experimentální linie pro CESLAB
- Creator:
- Petr Mikulík
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Věda. Všeobecnosti. Základy vědy a kultury. Vědecká práce, výzkum a vývoj, synchrotrony, urychlovače, research and development, synchrotrons, accelerators, 12, and 00
- Language:
- Czech
- Description:
- Petr Mikulík.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
39794. Urysohn’s lemma, gluing lemma and contraction∗ mapping theorem for fuzzy metric spaces
- Creator:
- Roja, Elango, Uma, Mallasamudram Kuppusamy, and Balasubramanian, Ganesan
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- fuzzy contraction mapping and fuzzy continuous mapping
- Language:
- English
- Description:
- In this paper the concept of a fuzzy contraction∗ mapping on a fuzzy metric space is introduced and it is proved that every fuzzy contraction∗ mapping on a complete fuzzy metric space has a unique fixed point.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
39795. Usazené srážky: jejich význam a výzkum
- Creator:
- Jaroslav Fišák and Miroslav Tesař
- Type:
- article, články, model:article, and TEXT
- Subject:
- Věda. Všeobecnosti. Základy vědy a kultury. Vědecká práce, Ústav fyziky atmosféry (Akademie věd ČR), Ústav pro hydrodynamiku (Akademie věd ČR), věda, vodní srážky, znečišťující látky, meteorologie, science, Kapské Město (Jihoafrická republika), usazené srážky, horizontální srážky, okultní srážky, 12, and 00
- Language:
- Czech
- Description:
- Když se většina lidí setká s pojmem atmosférické srážky, představí si déšť, sníh, případně déšť se sněhem, ať již ve formě trvalých srážek nebo přeháněk. Málokdo si ale uvědomuje, že tvoří pouze jednu složku. Jde o srážky padající, někdy též označované jako vertikální. Existuje však i další forma atmosférických srážek, tzv. usazené, nesprávně též horizontální či okultní. and Jaroslav Fišák, Miroslav Tesař.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
39796. Use of a right ventricular continuous flow pump to validate the distensible model of the pulmonary vasculature
- Creator:
- Vanden Eynden, F. , Segers, P., Bové, T. , De Somer, F., El Oumeiri, B., and Van Nooten, G.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Pulmonary circulation, Distensibility, Assist device, and Vascular resistence
- Language:
- English
- Description:
- In the pulmonary circulation, resistive and compliant properties overlap in the same vessels. Resistance varies nonlinearly with pressure and flow; this relationship is driven by the elastic properties of the vessels. Linehan et al. (1982) correlated the mean pulmonary arterial pressure and mean flow with resistance using an original equation incorporating the distensibility of the pulmonary arteries. The goal of this study was to validate this equation in an in vivo porcine model. In vivo measurements were acquired in 6 pigs. The distensibility coefficient (DC) was measured by placing piezo-electric crystals around the pulmonary artery (PA). In addition to experiments under pulsatile conditions, a right ventricular (RV) bypass system was used to induce a continuous pulmonary flow state. The Linehan's equation was then used to predict the pressure from the flow under continuous flow conditions. The diameter-derived DC was 2.4 %/mmHg (±0.4 %), whereas the surface area-based DC was 4.1 %/mmHg (±0.1 %). An increase in continuous flow was associated with a constant decrease in resistance, which correlated with the diameter-based DC (r=-0.8407, p=0.044) and the surface areabased DC (r=-0.8986, p=0.028). In contrast to the Linehan’s equation, our results showed constant or even decreasing pressure as flow increased. Using a model of continuous pulmonary flow induced by an RV assist system, pulmonary pressure could not be predicted based on the flow using the Linehan’s equation. Measurements of distensibility based on the diameter of the PA were inversely correlated with the resistance.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
39797. Use of conventional flow resistance equations and a model for the Nikuradse roughness in vegetated flows at high submergence
- Creator:
- Gualtieri, Paola, De Felice, Sergio, Pasquino, Vittorio, and Doria, Guelfo Pulci
- Type:
- article, model:article, and TEXT
- Subject:
- open channel flows, vegetated flows, rigid vegetation, flow resistance, roughness coefficients, and Nikuradse equivalent sand-grain roughness
- Language:
- Slovak
- Description:
- This study examines the problem of flow resistance due to rigid vegetation in open channel flow. The reliability of the conventional flow resistance equations (i.e. Keulegan, Manning and Chézy-Bazin) for vegetated flows at high submergence, i.e. h/k >5, (where h = flow depth and k = vegetation height) is assessed. Several modern flow resistance equations based on a two-layer approach are examined, showing that they transform into the conventional equations at high submergences. To compare the conventional flow resistance equations at high submergences, an experimental methodology is proposed and applied to the experimental data reported in the literature and collected for this study. The results demonstrate the reliability of the Keulegan equation in predicting the flow resistance. Based on the obtained results, a model to evaluate the Nikuradse equivalent sand-grain roughness, kN, starting from the vegetation height and density, is proposed and tested.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
39798. Use of electrogastrography in preclinical studies of cholinergic and anticholinergic agents in experimental pigs
- Creator:
- Jaroslav Květina, Ilja Tachecí, Pavlík, M., Marcela Kopáčová, Stanislav Rejchrt, Tomáš Douda, Martin Kuneš, and Jan Bureš
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie, physiology, electrogastrography, experimental pigs, atropine, neostigmine, 14, and 612
- Language:
- English
- Description:
- Electrogastrography (EGG) is a non-invasive method for the assessment of gastric myoelectrical activity. Porcine EGG is comparable with human one. The purpose of this study was to evaluate the effect of atropine and neostigmine on the EGG in experimental pigs. Adult female pigs were administrated atropine (1.5 mg i.m., n=6) and neostigmine (0.5 mg i.m., n=6) after the baseline EGG, followed by a 90-min trial recording (MMS, Enschede, the Netherlands). Running spectral analysis was used for the evaluation. The results were expressed as dominant frequency of slow waves and EGG power (areas of amplitudes). Neostigmine increased continuously the dominant frequency and decreased significantly the EGG power. Atropine did not change the dominant frequency significantly. However, atropine increased significantly the EGG power (areas of amplitudes) from basal values to the maximum at the 10-20-min interval. After that period, the areas of amplitudes decreased significantly to the lowest values at the 60-90-min interval. In conclusion, cholinergic and anticholinergic agents affect differently EGG in experimental pigs., J. Květina, I. Tachecí, M. Pavlík, M. Kopáčová, S. Rejchrt, T. Douda, M. Kuneš, J. Bureš., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
39799. Use of flow cytometry in research on apomictic plants
- Creator:
- Krahulcová, Anna and Rotreklová, Olga
- Type:
- article and TEXT
- Subject:
- agamic complexes, cytotype, evolution, flow cytometry, genetic control of apomixis, genome size, hybridization, mixed populations, parthenogenesis, polyploidy, progeny screening, and residual sexuality
- Language:
- English
- Description:
- This paper reviews recent use of flow cytometry in studies on apomictic plant taxa. The most of apomictic angiosperms are polyploid, often differing in ploidy level from their sexual counterparts within the agamic complex. Flow cytometry is widely used for screening the ploidy levels of mature plants and their seed generated both in the field and in experiments. Routine ploidy screening often accompanied by molecular markers distinguishing individual genotypes are used to reveal novel insights into the biosystematics and population biology of apomictic taxa. Apomixis (asexual seed formation) is mostly facultative, operating together with other less frequent reproductive pathways within the same individual. The diversity in modes of reproduction in apomicts is commonly reflected in the ploidy structure of their progeny in mixed-cytotype populations. Thus, flow cytometry facilitates the detection and quantification of particular progeny classes generated by different reproductive pathways. The specific embryo/endosperm ploidy ratios, typical of the different reproductive pathways, result from modifications of double fertilization in sexual/apomictic angiosperms.Thus, the reproductive origin of seed can be identified, including autonomous or pseudogamous apomixis, haploid parthenogenesis and sexual reproduction, involving either reduced or unreduced gametes. Collectively, flow cytometry has been used to address the following research topics: (i) assessing the variation in ploidy levels and genome sizes in agamic complexes, (ii) detection and quantification of different reproductive modes in facultative apomicts, (iii) elucidation of processes in populations with coexisting sexual and apomictic biotypes, (iv) evolution of agamic complexes, and (v) genetic basis of apomixis. The last topic is of paramount importance to crop breeding: the search for candidate gene(s) responsible for apomixis is the main objective of many research programmes. A list of the angiosperm taxa that could provide model systems for such research is provided.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/
39800. use of flow cytometry in the biosystematics, ecology and population bilogy of homoploid plants
- Creator:
- Loureiro, João, Trávníček, Pavel, Rauchová, Jana, Urfus, Tomáš, Vít, Petr, Štech, Milan, Castro, Sílvia, and Suda, Jan
- Type:
- article and TEXT
- Subject:
- biosystematics, ecology, flow sytometrry, genome size, homoploid species, hybridization, nuclear DNA content, population biology, and taxonomy
- Language:
- English
- Description:
- Over the last decade there has been a tremendous increase in the use of flow cytometry (FCM) in studies on the biosystematics, ecology and population biology of vascular plants. Most studies, however, address questions related to differences in genome copy number, while the value of FCM for studying homoploid plant groups has long been underestimated. This review summarizes recent advances in taxonomic and ecological research on homoploid plants that were made using FCM. A fairly constant amount of nuclear DNA within each evolutionary entity together with the often large differences between species means that genome size is a useful character for taxonomic decision-making. Regardless of the number of chromosomes, genome size can be used to delimit taxa at various taxonomic levels, resolve complex low-level taxonomies, assess the frequency of interspecific hybridization or infer evolutionary relationships in homoploid plant groups. In plant ecology and evolutionary biology, variation in genome size has been used for prediction purposes because genome size is associated with several phenotypic, physiological and/or ecological characteristics. It is likely that in the future the use ofFCM in studies on taxonomy, ecology and population biology of homoploid plants will increase both in scope and frequency. Flow cytometry alone, but especially in combination with other molecular and phenotypic approaches, promises advances in our understanding of the functional significance of variation in genome size in homoploid plants.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/