National Repository of Grey Literature 19,696 records found  1 - 10nextend  jump to record: Search took 0.72 seconds. 

Radiative Heat Transfer at Low Temperatures over Microscopic Distances in Vacuum
Králík, Tomáš ; Musilová, Věra ; Hanzelka, Pavel ; Horák, Michal ; Srnka, Aleš
We present experimental results on heat transfer between plane parallel surfaces of samples separated with microscopic vacuum gap. Radiative heat flux between metallic samples exceeding 50 times heat flux between black surfaces was observed for gaps of several micrometres at temperatures below 50 K. Comparison with near field theory of radiative heat transfer is presented.

Impact of low oil and natural gas prices on the economy of Qatar since 2014
Šamánek, Ondřej ; Stuchlíková, Zuzana (advisor) ; Hasík, Gabriel (referee)
The bachelor thesis examines the impact of the oil and gas prices slump, which befell the world in 2014, on the economy of Qatar. The main objective of the thesis is to evaluate if and to what extend the price collapse influenced the relevant economic indicators and behaviour of the state and companies active in the affected field. The selected objective is examined using the method of data comparison, namely before and after the price slump, and with the help of the case study, in which the qatari company operating in the oil and gas is examined. From the conducted analysis it is possible to conclude that Qatar was directly influenced by the oil and gas prices collapse: its GDP slumped, fiscal deficit increased. The analysed company also experienced troubles caused by low prices: one year after the price slump, total amount of assigned tenders to company decreased substantially and historically high number of tenders was cancelled. Conclusions deriving from the thesis might be applied to other oil and gas export economies in the Persian Gulf, for fundamental traits of such economies are shared with the economy of Qatar.

Proposed marketing strategy of a low-cost airline
Khomutova, Sofia ; Král, Petr (advisor) ; Tročil, Jan (referee)
My Master thesis focuses on the design of the marketing strategy of a low-cost airline SparrowJet. The first chapter of the theoretical parts contains the required basics of theoretical information necessary to develop a marketing plan. In the second chapter is an analysis of the air transportation market with an emphasis on the low-cost segment. The final chapter of the theoretical part is dedicated to the marketing mix in the transportation. The practical part of my thesis begins with the situation analysis, which includes: the PEST analysis, Porters five forces analysis, a competition analysis and a customer analysis. My work is concluded with a complete proposal of a marketing strategy for the airline, including both basic strategy of S-T-P and a marketing mix.

Freezing technology of bull sperm in relation to its survivability and fertilization ability
Doležalová, Martina ; Stádník, Luděk (advisor) ; Jiří, Jiří (referee)
The aim of optimalization the insemination doses production is to provide the highest fertilization ability of spermatozoa during the demanding proces of processing fresh semen and its subsequent cryopreservation. Temperature changes causes spermatozoa damage during the cooling and freezing. Spermatozoa is exposed to cold shock and many others limiting factors, which leads to cell death and therefore to decline of fertilization ability of thawed insemination doses. For increasing spermatozoa resistance, exactly the plasma membrane resistance against cold shock was fraction of egg yolk LDL cholesterol (low density lipoprotein) at various concentrations into the comercially produced diluents added. It is believed that LDL acts possitively to plasma membrane and helps to maintain the fertilization ability of spermatozoa after thawing. Following step in the proces of insemination doses production is slow cooling of diluted semen and equilibration, when the straws are store at cooling box for 30 minutes to 240 hours. This period is necessary to penetrate of certain diluent components into the spermatazoa also maintain the balance between their intracellular and extracellular concentration. Also important is subsequent freezing temperature gradient of insemination doses. The most suitable freezing method is based on computer controlled temperature decline in freezing chamber which allows the precise control of ice crystals formation that could tear and kill the cell. During 2012 to 2016 was repeatedly collected semen from the group of breeding bulls (n = 27, Holstein and Czech Fleckvieh breed) at AI centre. Semen which fulfill the standard entrance conditions in first step was evenly into several parts divided. For dilution the three types of comercially diluents AndroMed, Bioxcell and Triladyl with and without LDL addition were used. Into the diluents AndroMed and Bioxcell the concentration of LDL 4 %, 6 % and 8% into the dilent Triladyl 6 %, 8 % and 10 % was added. Diluted semen was filled into the glass capillares with volume 0,1 ml and temperature +4 °C. Subsequently the sample was placed to cold bath (0°C) for 10 minutes. Then the volume of capillare with physiological solution (37 °C) was mixed and for next 120 minutes was incubate. The effect of cold shock to proportion of live spermatozoa was evaluated by using Eosin and Nigrosine staining technique during heat test of spermatozoa survivability after spermatozoa heating and after 120 minutes of incubation. The more suitable semen diluents which provide the higher spermatozoa resistance against cold shock were AndroMed and Bioxcell. Together the possitive effect of LDL addition into the diluents to lower decrease of proportion of live spermatozoa during heat test was found (P<0.05). The most suitable LDL concentration which had a favorable influence at spermatozoa resistance against cold shock was 6 % in diluent Bioxcell. Values of the proportion of live sperm were higher at the beginning of the heat test (+1.31% to + 3.2%) and after 120 minute incubation (+5.82% to +8.41%) compared to other diluents with and without addition of LDL. In the next step the process of equilibration was optimized, is an important part of insemination doses production. The effect of the length of equilibration for subsequent fertilization ability of spermatozoa was evaluated using spermatozoa motility based of CASA and proportion of live spermatozoa after thawing and during heat survival test lasting 120 minutes (37 ° C). Suitable semen was diluted by comercially used diluent AndroMed based on soya lecithin, filled into the straws (0.25 ml), cooled and equilibrated in cooling box for 30, 120 and 240 minutes and freezed in programmable freezing box applying four types of freezing curves differing in temperature rate decline. There was used standard and by producer recommended 3. phase freezing curve, then 2. phase freezing curve, and 3. phase freezing curve with slower as well as rapid decline of temperature rate in freezing chamber, compared with standard freezing curve. The highest spermatozoa motility was found using 240 minutes of equilibration by +2.72% and +4.58% compared to other lengths of equilibration (P <0.05 to 0.01). The highest proportion of live spermatozoa was found using 120 minutes of equilibration (+6.87 % and +8.68 %). The highest average spermatozoa motility during heat test after thawing was achieved by using 2. phase freezing curve (from +2.97% to +10.37%, P <0.05), also in the proportion of live spermatozoa (from + 4.37% to +8.82%, P <0.01). When evaluating interaction between the length of equilibration and freezing curve (standard 3. phase and 2 . phase freezing curve), the highest average spermatozoa motility and proportion of live spermatozoa using 240 minutes of equilibration by both freezing curves was reached, there was no statistically significant differences. As well as, in all evaluated parts of this study the individual differences between ejaculate of bulls and within semen from one bull (P <0.05) as secondary effect were found. To maintain good fertilization ability of semen during cryopreservation is necessary to increase the spermatozoa resistance against cold shock using addition of correct concentration of LDL into the commercially used diluents AndroMed and Bioxcell. Subsequently the fertilization ability of insemination dose is influenced by cooling, the length of equilibration and freezing. The length of equilibration 120 minutes and more as well as gentle way of freezing according to freezing curve, which ensures a gradual decrease of temperature in freezing chamber provided the higher average spermatozoa motility and proportion of live spermatozoa.

Total contents and speciation of arsenic and selenium in plants growing in soils with different physico-chemical properties
Tremlová, Jana ; Száková, Jiřina (advisor) ; Vymazal, Jan (referee)
This dissertation thesis deals with uptake, accumulation and transformation of arsenic and selenium in plants growing on soils with different chemico-physical soil properties. The contents of arsenic were investigated in 99 wild plant species, coming from 27 different families and 6 different vegetables growing in arsenic contaminated soils. The results suggest that there are species-specific mechanisms which protects certain plants from the excessive uptake of arsenic from the soil. On the other hand, there are plants using a strategy of accumulation, which theoretically may increase the risk of arsenic entry into the food chain, whether through grazing cattle and wildlife or through consumption of vegetables growing on arsenic contaminated soils. The most prevalent arsenic compounds are AsV and AsIII. Other arsenic compounds occure as minor species. An important finding was detection of arsenobetaine in Plantago lanceolata L. and Carex praecox Schreb .. The contents of selenium were examined in 73 species of wild plants, coming from 29 different families. The results suggest that naturally low levels of selenium in the soil of selected locations along with a low capability of selenium uptake via collected plant species lead to the low content of selenium in plant biomass which may contribute to selenium deficient throughout the food chain. Foliar application of selenate on wild plant communities and on some types of vegetables in our case Brassica oleracea var. italica can have a positive impact on increasing the selenium content in the aboveground biomass of these plants and by extension, increase the selenium content in the human diet. Dominant selenium compounds in the aboveground biomass of the analyzed plants were SeVI and selenomethionine, with variable proportion of other commonly occurring organic selenium compounds, which is mainly affected by plant species.

Air refractive index measurement using low-coherence interferometry
Pikálek, Tomáš ; Buchta, Zdeněk
Paper deals with a new direct air refractive index measurement method. In this method, the air refractivity is calculated from the optical path difference between two parts of a permanently evacuated double-spaced vacuum cell that is measured by means of a combination of laser and low-coherence interferometry.

Optimization of network flow monitoring
Žádník, Martin ; Lhotka,, Ladislav (referee) ; Matoušek, Radomil (referee) ; Sekanina, Lukáš (advisor)
The thesis deals with optimization of network flow monitoring. Flow-based network traffic processing, that is, processing packets based on some state information associated to the flows which the packets belong to, is a key enabler for a variety of network services and applications. The number of simultaneous flows increases with the growing number of new services and applications. It has become a challenge to keep a state per each flow in a network device processing high speed traffic. A flow table, a structure with flow states, must be stored in a memory hierarchy. The memory closest to the processing is known as a flow cache. Flow cache management plays an important role in terms of its effective utilization, which affects the performance of the whole system. This thesis focuses on an automated design of cache replacement policy optimized to a deployment on particular networks. A genetic algorithm is proposed to automate this process. The genetic algorithm generates and evaluates evolved replacement policies by a simulation on obtained traffic traces. The proposed algorithm is evaluated by designing replacement policies for two variations of the cache management problem. The first variation is an evolution of the replacement policy with an overall low number of state evictions from the flow cache. The second variation represents an evolution of the replacement policy with a low number of evictions belonging to large flows only. Optimized replacement policies for both variations are found while experimenting with various encoding of the replacement policy and genetic operators. The newly evolved replacement policies achieve better results than other tested policies. The evolved replacement policy lowers the overall amount of evictions by ten percent in comparison with the best compared policy. The evolved replacement policy focusing on large flows lowers the amount of their evictions two times. Moreover, no eviction occurs for most of the large flows (over 90%). The evolved replacement policy offers better resilience against flooding the flow cache with large amount of short flows which are typical side effects of scanning or distributed denial of service activities. An extension of the replacement policy is also proposed. The extension complements the replacement policy with an additional information extracted from packet headers. The results show further decrease in the number of evictions when the extension is used.

Fluorescent analysis of the differential protein expression in normozoospermic and asthenozoospermic sperm samples
Děd, Lukáš ; Čapková, Jana ; Kubátová, Alena ; Teplá, O. ; Pěknicová, Jana
Asthenozoospermia is one of the main seminal pathologies underlying male infertility. Previous proteomic studies have demonstrated the significant differences in the protein profiles between normozoospermic and asthenozoospermic sperm samples. Since these studies were primarily focused on the identification of differentially expressed proteins by mass spectrometry, we aimed to evaluate the ability of our diagnostic antibodies to detect the differential expression of selected protein markers by fluorescent microscopy and flow cytometry techniques. Therefore, we analyzed sperm samples from 30 men with normal and 30 men with astheno spermiograms, average by the panel of our diagnostic anti-human sperm (Hs) antibodies. Fluorescent microscopy and flow cytometry analysis revealed quantitative differences in the protein abundances between normo and astheno sperm samples, namely, in GAPDHs, evaluated with Hs-8 MoAb, VCP, evaluated with Hs-14 MoAb, and ATP synthase, evaluated with MoAb Hs-36. From the methodological point of view, we observed very high correlation between the data obtained by fluorescent microscopy and flow cytometry techniques and therefore both methods are useful for evaluation of protein differences associated with asthenozoospermia. From the clinical point of view, we observed the strong association of the low sperm motility in the sample with the expression of proteins, playing an important role in sperm energy metabolism (expected), but also with the expression of all tested intra-acrosomal proteins. These findings further demonstrate asthenozoospermia as a complex semen disorder frequently associated with other semen pathologies, which are not diagnosed by basic semen analysis, and the possibility to use monoclonal antibodies as a tool for diagnosis of protein associated sperm pathologies in the semen with the low sperm motility.

How to prevent the proliferation of Legionella pneumophylis in hot water in the hospital Czech Krumlov
TUREK, Jan
This diploma thesis deals with microbiological quality of hot water in a hospital in Cesky Krumlov as well as hot water piping condition with respect to Legionella. It also deals with arrangements for improving the quality of hot water in this hospital. The subject and target of this thesis are the findings of the mentioned parameters based on own observations, technical documentation and analysis of warm water performed by an accredited laboratory. The hospital in Cesky Krumlov, the construction of which began in 1909, was built in 1911 as the 'Nemocnice Císaře Františka Josefa I.' As the time went by, new buildings were built up. The hospital was renamed to 'Všeobecná veřejná nemocnice' in 1942. In the following years the hospital expanded until the current condition. Water quality and presence of Legionella is a world-wide issue, which we must fight against. The thesis is divided into two parts. First, theoretical part, which includes both general and specific knowledge about Legionella, its health risks, the environment in which it occurs, possibilities of eliminating, suitability of the material for hot water pipes, gained in professional literature and a part of the Czech legislation dealing with public health protection, the law 'No. 258/2004 Coll.' in actual version and quality of drinking water and hot water. In the second, empirical part, I focus on the situation of the hospital in Cesky Krumlov from 2009 till 2015, concerning newly built boiler room and the whole distribution system of hot water regarding Legionella. Particularly I focused on materials used for ecologisation of the gas boiler room and materials used for hot water pipes and actual state of water distribution in individual buildings of this health care facility. I mentioned the analysis of the water samples performed by an accredited laboratory with corresponding technical documentation, which concerns the water distribution system, provided by the medical facility. I used secondary data analysis to evaluate these documents. Regarding the results from 2009 to 2015 the microbiological quality of warm water doesn't meet the limits defined in the Attachment No. 3 of the above mentioned law Order 252/2004 Coll. Limit value for colony forming units of Legionella is set to maximum of 100 CFU. In most of the samples this limit was exceeded by series of units up to hundred thousands of units. The last results in 2015 prove improvement of the unfavorable situation. In that year the analysis was tested three times. First in February, where the CFU units were 'only' in hundreds, with the top value of 550 CFU in the Postacute Care ward. Second analysis was performed in June that same year. Results were acceptable. The highest value was 64 CFU. Last analysis in the hospital was performed in December. Increased concentration of Legionella was again in the Surgery building. There were established of 1400 colony forming units. There were 300 CFU in the Postacute Care ward and the limit value of 100 CFU was in the ward of Internal medicine. The answers to research questions 'How to prevent reproduction of Legionella peumophylis in the water distribution system of the hospital in Cesky Krumlov?' and 'How to ensure a sufficient amount of quality hot water in the medical facility?' are included at the end of the stated recommendations. A risk factor causing the fast reproduction of Legionella is the old water distribution system in most of the buildings and low water temperature of water leaving the boiler, which is 55°C. All mentioned results and evaluations are included in this thesis as well as attached pictures, which show the environment and situation within the Health Care Institutions.

Effect of sex on growth and formation of dorsal muscle of pigs
Fáberová, Gabriela ; Čítek, Jaroslav (advisor) ; Zadinová, Kateřina (referee)
Effect of sex on growth and formation of dorsal muscule of pigs Summary The aim of this thesis is to determine the influence of gender on the growth and formation of the pigs dorsal muscle. Growth is one of the basic phenomenon characterizing living organism. Is a creation of nonliving to living matter. The amount of body mass is not constant through the life, it is changing significantly. In the early postnatal period is skeleton growing faster compared to muscles and fat then leads to faster growth of muscle and in the last period called maturity to the fattening. Evaluating growth has a significant gender effect. In case of pigs, it is common to feed barrows and gilts. Nowadays it begins to think about feeding of boars or the imunocastrates. Due to different hormonal activities we can expect different muscle and fat deposition. The task of this study was to clarify the influence of gender on the formation and growth of pigs dorsal muscle. There were 72 pigs tested in total. Pigs were housed in pairs in cotes and divided by gender for pigs, boars, imunocastrates and sows. This subpopulation of genotype DanBred animals were divided to 1/4 (18ks) uncastrated male pigs (K) 1/4 (18ks) hormonally castrated male pigs (I), 1/4 (18ks) barrows (V) and 1/4 (18ks ) gilts (P). Average live weight of pigs at the start of the trial was 28.5 kg, while the test was conducted to average 107 kg bodyweight. Through all time pigs were fed ad-libitum KKS. During the test it was monitored at weekly intervals individual live weight, back fat thickness at A, B, muscle depth at A, B and the total percentage of muscle for all categories of pigs. The obtained results show that the growth and formation of a long dorsal muscle are influenced by gender. When comparing the weight in a given period, we conclude that during the time the difference between gilts and imunocastrates grow up. Best growth had imunocastrates gilts similarly, only was there an earlier stop of the growth. The highest increase in fat and muscle measured at the A and B, occurred in pigs, in sows we can see increasing gains in fat with respect to the period in which they are fattening. Boars had the lowest backfat thickness, imunocastrates. With imunocastrates we evaluate low fat increase compared to the beginning of the observation. The biggest muscle depth measured at A and B had the barrows with gilts and imunocastrates and especially boars did not reach the values as barrows and gilts, who had the highest muscle depth. Biggest % of muscle was measured in sows. A large proportion of muscle can be seen in male pigs. The proportion of muscle mass of imunocastrates was under the average and worst ratio of muscle had especially at the end of feeding barrows indicating that with increasing age there is a significant fattening, compared to the remaining groups of pigs Keywords: pig, growth rate, muscle fibers