• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 119
  • 49
  • Tagged with
  • 168
  • 157
  • 23
  • 16
  • 15
  • 15
  • 15
  • 14
  • 13
  • 13
  • 12
  • 10
  • 10
  • 10
  • 10
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Meta-učící metody pro analýzu trendů her Go / Meta-learning methods for analyzing Go playing trends

Moudřík, Josef January 2013 (has links)
This thesis extends the methodology for extracting evaluations of players from samples of Go game records originally presented in (Baudiš - Moudřík, 2012). Firstly, this work adds more features and lays out a methodology for their comparison. Secondly, we develop a robust machine-learning framework, which is able to capture dependencies between the evaluations and general target variable using ensemble meta-learning with a genetic algorithm. We apply this framework to two domains, estimation of strength and styles. The results show that the inference of the target variables in both cases is viable and reasonably precise. Finally, we present a web application, which realizes the methodology, while presenting a prototype teaching aid for the Go players and gathering more data. Powered by TCPDF (www.tcpdf.org)
52

Ontogeneze a evoluce velikosti a pohlavní dvojtvárnosti u plazů / Ontogeny and evolution of body size and sexual size dimorphism in reptiles

Frýdlová, Petra January 2013 (has links)
Monitor lizards (Varanidae) are morphologically very uniform in body shape, but much diversified in body size along both phylogenetic and ontogenetic axes. A striking sexual size dimorphism exists in monitor lizards; they are capable of fast growth, metabolism and sexual maturation. I collected the data concerning body size of particular species and verified the validity of Rench's rule, which said that there is bigger difference in body size of a conspecific male and females growing with larger body size of the species. Males are markedly bigger than females. In the next step, I focused on the model species of monitor lizards, Varanus indicus. I monitored its ontogeny very carefully. I found that this monitor lizard has pronounced sexual size dimorphism, but there are only small differences in body shape. It is capable of rapid growth and sexual maturation. The sexual dimorphism in body shape is only poor, but still measurable right in those places where the selection pressures were expected. Blood sampling monitored biochemical and haematological parameters. The concentrations of the biochemical parameters revealed the economy of resources of particular sexes partially, the costs of body growth and reproduction. Although both sexes produce the same amount of biomass (the body growth of males vs. the...
53

Fenomén symbiózy a jeho význam pro teoretickou biologii / The phenomenon of symbiosis and its importance to theoretical biology

Lhotský, Josef January 2015 (has links)
7 Abstract Close physical interspecific associations called symbioses are central for understanding both evolution and interactions of all branches of living creatures, as well as shaping the Earth's physical features - in other words, they are essential for understanding the nature of whole biosphere. Symbiotic research takes place in some variation in all fields of biology, and since the nature of the phenomenon apparently has a fundamental importance as an exceptional underlying & unifying scheme, there is growing need for appropriate theoretical analysis. Here I discuss the theoretical frame, definition and history of the concept of symbiotic interactions and its significance and use in theoretical biology. Keywords: symbiosis, life, microorganisms, evolution, metaphors and models
54

Adaptace XML dokumentů a integritní omezení v XML / XML Document Adaptation and Integrity Constraints in XML

Malý, Jakub January 2013 (has links)
This work examines XML data management and consistency -- more precisely the problem of document adaptation and the usage of integrity constraints. Changes in user requirements cause changes in schemas used in the systems and changes in the schemas subsequently make existing documents invalid. In this thesis, we introduce a formal framework for detecting changes between two versions of a schema and generating a transformation from the source to the target schema. Large-scale information systems depend on integrity constraints to be preserved and valid. In this work, we show how OCL can be used for XML data to define constraints at the abstract level, how such constraints can be translated to XPath expressions and Schematron schemas automatically and verified in XML documents.
55

Molecular phylogeny and genome evolution of insect symbiotic bacteria / Molecular phylogeny and genome evolution of insect symbiotic bacteria

NOVÁKOVÁ, Eva January 2012 (has links)
Since the introduction of advanced molecular methods the research on insect bacterial symbioses underwent a major focus shift towards large scale phylogenetics and comparative genomics. These new fields provided answers to several fundamental questions of symbiont evolution, functional capabilities of the host-associated bacteria, and the role of symbionts in the host?s biology. However, the vast diversity and complexity of symbiotic relationships still leaves gaps in our understanding to a rich mosaic of various symbiont types, effects and transitions from facultative association to obligate mutualism. The presented study focuses on distribution, diversity, phylogenetic patterns, evolutionary transitions and genome evolution of two less known but ecologically diverse bacterial genera, Arsenophonus and Sodalis. The thesis also takes advantage of the knowledge on a well established symbiotic model between aphids and Buchnera and reveals several evolutionary patterns in the host and symbiont.
56

Molekulární aspekty mezidruhové hybridizace jeseterovitých ryb ve vztahu k polyploidii a in situ konzervaci / Molecular aspects of interspecific hybridization of sturgeons related to polyploidy and in situ conservation

HAVELKA, Miloš January 2013 (has links)
Sturgeons (Chondrostei: Acipenseriformes) display markedly disjunct distributions with a wide occurrence in the northern hemisphere. Their unique benthic specializations, conserved morphology, evolutionary age, the variation in their basic diadromous life history, and the large public interest due to their near extinction or critically endangered status make sturgeons and paddlefishes one of the most interesting group of vertebrates. In addition to that, ploidy diversity of Acipenseriformes possessing three ploidy groups having ~ 120 chromosomes, ~ 240 ? 270 chromosomes and ~ 360 chromosomes provides unique model for investigation of evolutionary processes which were going through the genome duplication events. Sturgeons are also notoriously known for their strong propensity to interspecific and intergeneric hybridization which can result in hybrids with various ploidy levels. All these facts make sturgeon genetics and cytogenetics a thriving but also complicated area for research. In the present work, the role of genome duplication and functional reduction evens in evolution of sturgeon species as well as sturgeons? ploidy levels and ploidy relationships among Acipenseriformes were investigated using molecular markers. In addition to that, clarification of origin of abnormal ploidy levels and observation of segregation pattern of microsatellite alleles in the course of hybridization of polyploid sturgeon species were included into this study. With regard to the all considerations and observations provided by this study we concluded that evolution of sturgeon species is still widely dynamic and ongoing process which might goes through the allopolyplodization as well as autopolyplidization events.
57

Evoluce zbarvení v řádu hrabavých / Evolution of coloration in the Galliformes

VALENZOVÁ, Zdeňka January 2010 (has links)
The coloration of plumage and ornaments in the groups Numididae, Odonthophoridae and Phasianidae (within the order Galliformes) was detailled described and analyzed. The ecological factors affecting the evolution of dichromatism and conspicuousness were tested.
58

Diverzita a fylogeneze archaméb / Diversity and phylogeny of Archamoebae

Zadrobílková, Eliška January 2016 (has links)
Members of the group Archamoebae are free-living or endobiotic amoeboid flagellates and amoebae. They live in anoxic or microoxic habitats, and their mitochondria have been reduced. They were originally thought to lack mitochondria and represent one of the earliest eukaryotes. However, this hypothesis has been refuted, and now it is evident that the Archamoebae belongs to the lineage Conosa within the supergroup Amoebozoa, together with aerobic slime molds (Macromycetozoa) and variosean amoebae and flagellates. Relatively simple microtubular cytoskeleton is a characteristic feature of Archamoebae. It consists of a single basal body from which a flagellum arises, lateral root, and microtubular cone. Cytoskeleton of aflagellated genera has been completely reduced. About 350 species names of Archamoebae have been created so far. However, most descriptions were based on inadequate morphological features. The identity of numerous species is uncertain, and many of them are likely synonymous. Another problem is a small amount of available molecular data. During our project, we have substantially improved the dataset of DNA sequences of archamoebae. On the basis of molecular and morphological data, we described 13 new species. We showed that genus Rhizomastix belongs to Archamoebae and displays a new type...
59

Výskyt a charakterizace sekundárních struktur u nových proteinových sekvencí (never born proteins) / Never Born Proteins: Occurence and characterization of secondary structure motifs

Treťjačenko, Vjačeslav January 2015 (has links)
An experimental study on randomly generated protein sequences can provide important insights into the origin and mechanism of secondary structure formation and protein folding. In this study we bring biophysical characterization of five protein sequences selected from the in silico generated library of random chains. The sequences were selected on the basis of bioinformatic analysis in order to find the candidates with the maximum potential to possess secondary structure. This study shows that the random polypeptide sequences form stable secondary structures and in some show the signs of tertiary structure, such as hydrophobic core formation and distinctive oligomerization pattern. While the work presented in this thesis is work in progress on a larger study, the data already demonstrate that unevolved protein sequence space provides a lot of potential for secondary and tertiary structure formation that awaits its characterization. Powered by TCPDF (www.tcpdf.org)
60

Občanský aktivismus v ČR / Civic engagement in the Czech Republic

Lokajíček, Jan January 2012 (has links)
Because of contemporary unsatisfactory political situation in the Czech Republic, caused by presence of widespread corruption networks, many civic initiatives have been established to improve the status quo. This diploma thesis describes two NGO's, which focus on electoral system change of the lower chamber of the parliament of the Czech Republic. These organizations are Přímá volba poslanců 2014 (Direct election of Members of Parliament 2014) and electoral reform of Karel Janeček which is promoted by NGO Pozitivní evoluce (Positive evolution). The thesis is a comparative case study of these two organizations. The main goal is to do complex analysis of these two organizations, and identify interests, which lead them to pursue the electoral system change. Furthermore, basic effects of electoral systems and their changes are described. One of the chapters describes the development of the debate over the electoral system change in the past 20 years and mentions the attitude of contemporary political parties and their representatives to electoral system reform.

Page generated in 0.0345 seconds