• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 291
  • 90
  • 5
  • Tagged with
  • 386
  • 291
  • 47
  • 45
  • 45
  • 33
  • 31
  • 29
  • 26
  • 22
  • 22
  • 21
  • 20
  • 20
  • 20
  • 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.
101

Analýza a modelování struktury a vývoje smíšených porostů v oblasti Sudetské soustavy / Analysis and modeling of the structure and development of mixed forest stands in the Sudety mountains

Vacek, Zdeněk January 2016 (has links)
The thesis deals with analysis and modeling of the structure and development of selected mixed forests in protected areas of the Sudeten system, especially in the Giant Mountains national parks, Protected Landscape Area Broumovsko and Orlické Mountains, but also in other areas of the Czech Republic. This study is composed of a set of six published manuscripts that are covering three thematic ranges: structure of forest stands, regeneration of forest stands and forest modeling. The main objective of this work was to evaluate a vertical, horizontal and species structure, total diversity and development of mixed forest stands in central Sudetes. The partial aim was to analyse production parameters of forest stands, effect of microrelief and game on natural regeneration and assessment of dead wood in the area of interest. Further, the objective of the study was to develop explicit and non-explicit crown width and slenderness quotient models for Norway spruce (Picea abies L.) and European beech (Fagus sylvatica L.) and to predict the development of mixed forest ecosystem using growth simulations and to evaluate parameters and interactions among stand structure, climatic factors and natural regeneration, using especially analysis of variance, correlation matrix, spatial statistic and multivariate analysis. For this purpose a system of permanent research plots was used, which are regularly monitored since 1980 or were newly established. Using mapping technology FieldMap, selected parameters were measured for tree layer, natural regeneration individuals and dead wood. The results showed that the spatial distribution of beech stands in optimum stadium changes with the altitude from the regular pattern through random to aggregated spatial pattern of beech forests near the timberline. The spatial distribution of natural regeneration is highly aggregated, distribution of stumps is random and horizontal structure of the centroids of the crowns is always more regularly distributed than stems due to crown plasticity. Browsing damage of the leading shoot by game is an important limiting factor for height growth of natural regeneration, especially for silver fir (Abies alba Mill.), rowan (Sorbus aucuparia L.) and sycamore maple (Acer pseudoplatanus L.). The study of the influence of microrelief on the growth of beech regeneration showed that the highest average height was found on slope and pits, while the lowest on the mounds. From the effect of climatic factors on the radial growth of trees, it was found that temperature is a limiting factor for growth in mountain areas, respectively that positive effect of temperature decreases with decreasing altitude and conversely the influence of precipitation increases. Finally, spatially explicit models (as opposed to non-explicit) described a larger part of the crown width variations for spruce and beech and of the slenderness quotient for spruce. The largest contribution to the models after breast diameter was dominant height.
102

Časově rozlišená spektroskopie světlem indukovaných procesů

KUZNETSOVA, Valentyna January 2017 (has links)
This Ph.D. thesis is devoted to the study of the photophysical properties of photosynthetic pigments. The brief introduction to the field is given in Chapter 1. In studies presented in the thesis, femtosecond pump-probe spectroscopy was used to determine the relation between the molecular structure of carotenoids and its spectroscopic properties. The experimental and data analysis methods are described in Chapter 2. Chapter 3 addresses the investigation of the effect of isomerization on excited-state dynamics of the carbonyl carotenoid fucoxanthin. In Chapter 4, the different response of carbonyl carotenoids to solvent proticity is used to estimate the structure of an unknown carotenoid from Chromera velia. In Chapter 5, spectroscopic properties of the S1 state of three linear carotenoids were studied after excess energy excitation in the S2 state. Chapter 6 presents a femtosecond spectroscopic comparison study of Orange and Red Carotenoid Proteins binding different carotenoids.
103

Pěstování kukuřice v praktických podmínkách zemědělského podniku / Maize growing in terms of selected agricultural company

FENCL, Lukáš January 2018 (has links)
The thesis follows up an assessment of germination and growth dynamics of maze, in relation to different processing of soil in the region of Kozojed in North Pilsen. This experiment was conducted in the year 2016. In utter overview of the thesis, we can find a description of the technological procedure of maze cultivation, and individual technological procedures of soil preparation in more detail. In the resultant part of the thesis, we find the evaluation of germination, height, number of plants per m2 (squared meter), and average number of sticks per plant; further evaluation of WTG (Weight of thousand grains) of individual growers' technologies, and the most important overall produce of maze biomass in four variants of soil processing. Examined variants in the thesis are as follows: Sowing into deeply processed soil (underlay), Sowing into stubble, Sowing into loosened soil (disk plow), Sowing into tillage. The results showed that in provided soil-climatic conditions the best came out maze that was sown into stubble. In total biomass yield was option No. 3. sowing in loosened soil, where the resulting income, 30, 21 t.ha-1. From variants No. 1. seed to uderlay it was 0,93 t.ha-1 and No. 2. sowing into stubble to 3,57 t.ha-1 less than option No. 1. The highest difference was in variant No. 4 in the plow, where the biomass yield was by 7.26 t.ha-1 lower than in variant No. 3.
104

Komunikace - triptych reliéfů / Communication - a relief triptych

UHERKOVÁ, Iveta January 2010 (has links)
ANOTATION My diploma thesis called ?Communication? consists of two parts ? a theoretical part and a practical part. The aim of the theoretical part is to clarify the motivational resources which strongly influenced the manipulation with the topic. This part deals with my inspiration, clarifies the reasons why I chose this topic, and it also deals with the material and the technological process until the final installation of the work. This part also consists of picture documentation, draw designs and plastic sketches. The second practical part deals with an artwork itself. The three ceramic reliefs are portraying converging horizontal lines. It is connected with a simple geometry which precisely explains the dynamics of the communication joints. The aim was to create abstract reliefs which express movement, a variety of directions, relevancy and harmony.
105

Molekulární dynamika jako prostředek pro studium biologických systémů / Molecular dynamics as a tool to study biological systems

SOVOVÁ, Žofie January 2013 (has links)
Molecular dynamics simulations are a theoretical method enabling to trace the movement of atoms within a system. The system studied is usually treated on the atomistic level, however its overall properties can be also described satisfactory if several atoms are handled as one particle (coarse-grained molecular dynamics). This thesis presents molecular modeling and (coarse-grained) molecular dynamics as tools for the description of different biologically relevant systems. The coarse-grained force field parameters had to be developed prior to characterization of the thylakoid membrane from cyanobacterium Synechocystis PCC6803. Two different compositions of the membrane were studied in order to reveal differences in their behavior. The PsbI subunit of photosystem II was embedded into the thylakoid membrane and its behavior, both as an isolated protein and as a cluster of several units, was described. The last system examined was the C-type lectin-like domain of NKR-P1, a surface receptor of natural killer cells. Attention was payed to its structural characterization.
106

Studium populace bobra evropského (Castor fiber) pomocí GPS systému a GIS metod a zhodnocení jeho role v lužních lesích jižní Moravy

Urban, Jakub January 2012 (has links)
No description available.
107

Klasická a kvantová chaotická dynamika v reaktivním rozptylu atomů a molekul. / Classical and quantum chaotic dynamics in reactive scattering of atoms and molecules.

Trnka, Jiří January 2018 (has links)
The thesis deals with quantum reaction dynamics of three-particle systems. The thesis summarizes main theoretical results about three-body problem in quantum mechanics. A simple two dimensional model of three-particle system corresponding to atom-diatom collision was studied as a part of this thesis. The model allows for vibrational excitation and reaction processes. Solution based on distorted-wave method and Schwinger variational principle is proposed to solve the model. Proposed method of solution is then applied to a system of three coupled Morse potential energy surfaces. Probabilities of possible proces- ses depending on energy of incoming particle were calculated using the proposed method of solution for two variants of coupled Morse PESs. 1
108

Hodnocení vlivů na životní prostředí - případová studie. Monitoring populační dynamiky lýkožroutů v plošných polomech po orkánu Kyrill. / Evaluation of the effects on the environment - a case study. The monitoring of bark-beetle population dynamics in the areal windbreak after Hurricane Kyrill.

VOJÍŘ, Lukáš January 2009 (has links)
My thesis deals with bark beetle in two model areas affected by disturbances in the Šumava Mountains which were caused by Hurricane Kyrill in January 2007. The localities are Černá hora and Kalamitní svážnice pod Trojmeznou. Monitoring on both of these localities was realized in a zone with no human intervention. On these two model areas population dynamics of bark beetle in areal blowdowns and spatial distribution of advance growth in the harmed area was determined. Based on the monitoring of individual localilities, we can presume population dynamics of bark beetle in the following years.
109

Sledování dynamiky prokysávání mléka vybranými mlékařskými kulturami / Evaluation of fermentation activity of chosen pure dairy cultures in milk and cultured milk products

KRAMPL, Pavel January 2008 (has links)
This work deals with dynamics of milk souring after injection with chosen dairy culture in dependence on varying conditions of cultivation and different quality of the cultural medium. The aim of this work is:  Evaluation of the influence milk heat treatment has on the rate of milk souring by chosen clear dairy cultures.  Evaluation of the influence temperature of the milk has on the rate of milk souring by chosen clear dairy cultures.  Evaluation of the influence the quality of the milk has on the rate of milk souring by chosen clear dairy cultures. In the first part of my work there will be described milk as a primary commodity, its technological and microbiology characteristics, division of dairy cultures used in general practice and their application. In the next part of the work there will be described methodology, the way the laboratory research has been made and what commodities have been used. In this part there is also mentioned how the researches was evaluated and in what way the obtained results were processed. The ending part contains description and summary of results of the research and there is hold a discussion and a comparison of the results with other authors.
110

Teoretické studium fotosystemu II, chlorozomů a flavoproteinu WrbA

PALENČÁR, Peter January 2007 (has links)
The power of the current computer clusters allows us to study relatively large biomolecular systems by theoretical computational methods, such as widely used classical molecular dynamics (MD) simulations, at atomic level on the time scale of tens of nanoseconds. The limiting factor for classical MD simulations on most of the physiologically relevant systems is the lack of available force field (FF) parameters. Three biomolecular systems were studied in this thesis, namely membrane protein photosystem II (PSII), green bacteria antennas called chlorosomes and flavoprotein WrbA from E. coli, and all of them contain molecules or molecular fragments for which no FF parameters are available. Therefore, development of new FF parameters for all non-protein molecules was performed by applying quantum-mechanics (QM) methods. Once all FF parameters were available, MD simulations were applied. The computational studies were based on the conditions from wet experiments performed earlier by our research group. For the first time, proposed light-induced conformational changes of the reaction center (RC) of PSII and subsequent changes in arrangement of PSII RC pigments, were confirmed and described at atomic level by series of MD simulations over 20 ns. Optical spectra calculated on equilibrated MD model of PSII RC were in better agreement with experimental analogues when compared with earlier calculations on static model of PSII RC taken from crystal structure. Successful application of classical mechanics, QM and advanced optical spectra calculations on PSII represents one of a few existing computational studies on similar membrane pigment-protein systems. In the case of chlorosomes, equilibrated molecular lamellar models were constructed and critical structural parameters were elucidated by series of MD simulations over 30 ns. The presented models are the first lamellar models of chlorosomes at such scale so far. The equilibrated MD models of flavoprotein WrbA based on recent crystal structure provides starting point for further theoretical studies aimed to elucidate structural details of proposed ping-pong mechanism.

Page generated in 0.0509 seconds