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Latitudinal effect on cold tolerance of a firebug Pyrrhocoris apterus
JANDA, Václav
This thesis deals with the relationship between the place of origin and the extend of cold hardiness of fire bug Pyrrhocoris apterus (Linnaeus, 1758). Thirteen populations from twelve European localities were used in the experiment. Linear regressions were used to relate the values of SCP (10th percentile, first quartile, mean and median) of the individual populations to minimum and average winter temperatures of given localities. The relationship between air temperatures and SCP values were significant provided that the data of all populations were used. After the removal of three southern non-diapausing populations this relationship lost its significance.
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Removal of Selected Components from the Aquatic Environment by Coagulation Process
Měřínská, Zuzana ; Márová, Ivana (referee) ; Janda, Václav (referee) ; Mergl, Václav (referee) ; Vávrová, Milada (advisor)
This thesis deals with coagulation treatment of surface water with content of humic matters, drug residues and turbidity. Commonly used coagulants (ferrous and aluminous sulphate) and natural biopolymer based on chitosan that not yet used in the Czech Republic had been studied. The aim of this work was to found the optimal application of chitosan in water treatment and comparison of its coagulation efficiency with standard inorganic coagulants. Theoretical part of the thesis contains occurrence, classification, composition, properties and importance of humic matters and drug residues and furthermore properties of chitosan and its using in water treatment. Experimental part summarizes the obtained results from the laboratory coagulation tests with inorganic coagulants and with chitosan leading to determination of its optimal dose. Other coagulation experiments were focused on finding the possibilities of combine the two coagulants (ferrous sulphate and chitosan) and to find their optimum doses and suitable ratio. The influence of pH on water treatment with using coagulation was also studied.
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Improvement of Manganese Separation in Drinking Water Treatment
Bartoš, Ladislav ; Janda, Václav (referee) ; Hlaváč, Jaroslav (referee) ; Dolejš, Petr (advisor)
The submitted paper covers manganese comprehensively. The introduction provides an overview of its basic physical and chemical properties. Its compounds are discussed individually, including their preparation, production, and practical uses. Furthermore, a list of analytical methods in which manganese is involved in the form of its compounds as reagents is included. The same section includes an overview of analytical methods whereby manganese and its compounds are detected, primarily in water industry processes. Attention is paid to manganese as a non-negligible constituent of the various parts of the environment. The section on manganese’s biogenic properties is interesting from the viewpoint of its toxicity as well as its role as an important biogenic element, indispensable primarily for mammals. The subsequent chapters discuss the various methods which are suitable, under specific conditions, for separation in the treatment of surface and underground water aimed at producing drinking, process, or industrial water, where a minimal concentration of this metal is required. The impact of the physical/chemical conditions which influence the efficiency of separation in a manner ranging from non-negligible to principal, is discussed further on. Given the specifics of treatment of surface [and] underground water, the chapters provide more details on the processes suitable for specific types of matrix and specific conditions. Next chapters sum up many years of the author’s observations and experiences in the various parts of the water management system, from the raw water source to treatment to distribution, focusing on surface and underground water separately. Last chapter describes the construction of a water treatment plant model, its launch and calibration, and the tests focused on separating manganese by way of coagulation using aluminium and iron sulphate.
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Semiaquatic bugs as predators and prey and their use in natural history teaching
JANDA, Václav
The aim of this thesis is to create an overview of scientific findings about the prey and the predators of the representatives of infraorder Gerromorpha, their feeding habits and defence strategies against predators. Gerromorphans are adapted for life on the surface of various water bodies ranging from puddles to open ocean. Majority of water striders feed on insect fallen upon water surface, hatching larvae of aquatic insect or micro-crustacean. Gerromorphans locate their prey by sight and by sensory detection of ripples at water surface caused by prey. Gathering in schools turned out to be an efficient defence strategy against predators. Some species have compound eyes with specialized ommatidia which enable them to see prey on the surface as well as predator under surface. A proposal of the use of Gerromorpha in natural history teaching is part of this thesis. Gerromorphans are convenient for teaching of natural history thanks to the possibility of observation of piercing and sucking mouthparts and various food relations such as predation, cannibalism or kleptobiotic relation. Undemanding rearing of gerromorphans enables easy realization of experiments and observations under school conditions.
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