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Overweight and obesity in secondary school children
Šoukal, Jakub ; Bunc, Václav (advisor) ; Fialová, Ludmila (referee)
Title: Overweight and obesity in secondary school children Objectives: The main objective of this work is to compare eating habits of children (girls and boys) in the eighth and ninth grades in grammar schools and appropriate grades in gymnasium during the stay in a school. The thesis performs an analysis of the Decree no. 282/2016 Coll., which have come into effect on September 20th, 2016 (clearance sale is possible until January 1st, 2017) and restricts the offer of school food vending machines. Methods: The explorative method of questionnaire survey was used in the thesis. The descriptive approach was used to quantify the obtained data. The methods of comparison, logic, analysis and induction were applied for the analysis of the obtained data. The analysis method was used to analyse individual groups and methods of induction and logic were used while exerting general conclusions and rules. Thanks to the comparison method were compared all studied groups. The influence of food vending machines on children's eating habits was evaluated. Results: It was found that 44 % of girls in gymnasium uses vending machines, although they have a snack from home. In the other groups uses vending machines only 8-14 % of pupils. Follows from the results, that approximately half of pupils does not use food vending...
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Photochemical generation of volatile species of nickel for analytical atomic spectrometry methods
Šoukal, Jakub ; Musil, Stanislav (advisor) ; Kratzer, Jan (referee)
This thesis deals with optimization of conditions of photochemical generation of volatile species of nickel for atomic absorption spectrometry. The volatile species of nickel were generated in the flow arrangement, when sample was injected to a stream of a reaction medium. Either formic acid was used as the reaction medium or formic acid with the addition of formate anions. Two types of a generator were tested, a generator with a PTFE tube wrapped around a mercury UV lamp and a high efficiency generator with an inside channel. At the same time, two types of a gas-liquid separator were tested. Diffusion flame was used as an atomizer due to its high robustness. Quartz atomizer didn't provide higher sensitivity and measurements had worse repeatability. All the parameters affecting atomization in the diffusion flame were optimized (flow rates and composition of gases, observation height). In the next section, conditions of generation (irradiation time, HCOOH concentration, addition of formate anions) were optimized. Interferences of inorganic acids in photochemical generation were investigated as well. It was found out that the generator with the inside channel provided slightly higher sensitivity and thus generation efficiency than the generator with the PTFE tube wrapped around. Transmission of...
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Overweight and obesity in secondary school children
Šoukal, Jakub ; Bunc, Václav (advisor) ; Fialová, Ludmila (referee)
Title: Overweight and obesity in secondary school children Objectives: The main objective of this work is to compare eating habits of children (girls and boys) in the eighth and ninth grades in grammar schools and appropriate grades in gymnasium during the stay in a school. The thesis performs an analysis of the Decree no. 282/2016 Coll., which have come into effect on September 20th, 2016 (clearance sale is possible until January 1st, 2017) and restricts the offer of school food vending machines. Methods: The explorative method of questionnaire survey was used in the thesis. The descriptive approach was used to quantify the obtained data. The methods of comparison, logic, analysis and induction were applied for the analysis of the obtained data. The analysis method was used to analyse individual groups and methods of induction and logic were used while exerting general conclusions and rules. Thanks to the comparison method were compared all studied groups. The influence of food vending machines on children's eating habits was evaluated. Results: It was found that 44 % of girls in gymnasium uses vending machines, although they have a snack from home. In the other groups uses vending machines only 8-14 % of pupils. Follows from the results, that approximately half of pupils does not use food vending...
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Generation of volatile species of copper for atomic absorption spectrometry
Šoukal, Jakub ; Musil, Stanislav (advisor) ; Rybínová, Marcela (referee)
This thesis deals with optimization of conditions of chemical generation of volatile species of copper for atomic absorption spectrometry. The volatile species of copper were generated in the flow arrangement in a special generator by the reaction of the acidified sample with the solution of sodium borohydride in the presence of reaction modifiers. A diffusion flame was used as the atomizer of volatile species of copper due to its high robustness. First, all the parameters affecting atomization in the diffusion flame were optimized (flow rates and composition of gases, observation height). In the next section, concentration of individual reagents for chemical generation of volatile species was optimized, especially the concentration of nitric acid, sodium borohydride and reaction modifiers. Triton X-100 and Antifoam B were chosen as the best combination of modifiers with respect to threefold increase in sensitivity, tailing of measured signals and because of long-term repeatability. There was not observed any significant positive effect on the sensitivity of measurement for other tested reaction modifiers. The limits of detection and quantification were 62 mg dm−3 and 208 mg dm−3 , respectively. The repeatability of this method for concentration 2,5 mg dm−3 was 2,4%. Key words copper, chemical...
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