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Predictive models in survival analysis
Hadwigerová, Michaela ; Vítek, Martin (referee) ; Škutková, Helena (advisor)
With ever-new methods of treatment in health care occures a requierement of comparing these new methods to the old methods in some effective way. This is particularly important for the further development of these methods. However, data that describe these facts could not be processed by normal procedures and therefore was in the field of statistics to create a new kind of methods. They are known as predictive models of survival analysis.
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Not So Close That Breck
Smrekovský, Adam ; Jančík, Alexandr (referee) ; Šrámek, Jan (advisor)
How to stop working, and start catching dogs, and live alone on a hill and walk down only when you need to catch a dog. But it also stops entertaining you and you start thinking about village life. And so you run away from the end of the world to the village.
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Vliv světla a sucha na fotosyntézu a vodní provoz podrostních bylin temperátních doubrav
Vitásek, Roman
Woody plants, especially trees, affects the site microclimate. With their physiological manifestations, they influence hydrological and light conditions and, consequently, the composition and abundance of species from the plant community. A dense tree layer lowers the air and even more the surface temperatures. Its mitigating effect is most pronounced on hot summer days. While transpiration lowers air temperature, trees compete with understory for water. While the shade lowers surface temperature of understory, plants, as autotrophic organisms, need enough light for their survival. Therefore, the question arises, which density of forest canopy is optimal for the survival of understory during the global change that brings along increased temperatures and elevated levels of drought. I investigated how understory herbs cope with drought under simulated sparse and dense forest canopy. The focal species, European wild ginger (Asarum europaeum L.) and liverwort (Hepatica nobilis Schreb.), were divided into four groups: two of them were fully watered and two of them droughted. Each of the water regimes were divided in two groups, simulating sparse or dense canopy of woody overstory. The physiological response of plants (such as the rate of light-saturated photosynthesis, stomatal conductance, intrinsic water use efficiency, concentration of non-structural carbohydrates and water potential) on manipulated light and drought conditions was monitored under various levels of drought stress. The mortality was always higher under deep shade than under light conditions, despite different water management strategies of stomatal regulation. The European wild ginger has characteristics of an isohydric type of plant. During drought, it copes with the negative water potential by reducing stomatal conductivity, at the expense of the ability to actively fight water stress by creating assimilates. Under favorable conditions, this species stores starch that allow it to survive even with a significantly reduced rate of photosynthesis. The liverwort is more anisohydric in its behavior. With the increasing intensity of drought and increasing transpiration, it keeps the stomata open and by active photosynthesis it creates soluble carbohydrates for the production of osmotically active secondary metabolites. It has a very low level of stored starch, which can have a negative effect during prolonged drought. The results indicate that light plays an important role for plant survival under water stress. The changing climate brings along not only increased temperatures but often increased levels of summer drought. Therefore, growing in the understory of the dense forest does not always help the plant to survive warming climate.
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Umělý výtěr karase obecného
VRBENSKÝ, Jakub
The thesis briefly summarizes the available information in the field of crucian carp biology. The experimental part includes, firstly, monitoring the effect of water temperature during the latency period in reproductive females affects the success of artificial spawning, the survival of eggs to the eyespot stage, the length of the latency interval in hours and in clock degrees, the relative fecundity of reproductive females and the pGSI. In the second part of the experiment, secondly, the effect of the method of unstickness eggs on the survival of eggs to the eyespot stage. To test the effect of temperature during the latency interval, the females (mean weight 329 +- 60 g) were divided into 7 groups (n = 5). The individual groups of reproductive females were placed in separate tanks with average water temperatures of 15.4, 17.2, 18.9, 21, 23.2, 25.2 and 27.2 °C. Females and males were injected with the hormone Ovopel (1 pellet per 1 kg of fish). Before injection and artificial spawning, the reproductive fish were anaesthetized with clove oil (0.03 ml.l-1). The each group of females were artificially spawned, the eggs were seeded with a mixture of sperm from three males, activated with hatchery water and unsticked with cow's milk diluted with water (1:9). Incubation of eggs was carried out in small experimental Zug bottles (0.45 l) at an average temperature of 21 °C. The highest number of ovulated and artificially spawned females was found at temperatures of 21 - 25 °C (80 %). At lower and higher temperatures the success of spawning was lower. A close positive linear dependence of the latency interval length (in hours) on water temperature was found in the monitored range of 15.5 - 27.2 °C (y =-1.5062 x + 50.663; R2 = 0.924). The length of the latency interval at 21 and 23 °C was 18,4 +- 0,9 and 12,4 +- 0,2 h, respectively 387 +- 18 and 289 +- 5 h°. The eggs have a yellow-brown to green-brown colouration, the average weight of one unswollen eggs is 1,10 +- 0,07 mg (corresponding to 911 +- 51 thousand eggs in 1 kg of eggs). In contact with water, the eggs are very sticky. The highest relative working fecundity was achieved at 21 and 23 °C (71,9 +- 10 and 75,9 +- 34 thousand eggs per 1 kg of female). The average survival rate of eggs to the eyespot, originating from artificially spawned females kept during the latency interval at temperatures between 18,9 - 23,2 °C, ranged from 92.9 +- 0.5 to 99.6 +- 2.2 %, and was lower at 17.2 and 27.2 °C (86.2 +- 0.6 respectively 74.2 +- 3 %), differences between groups were statistically significant. In evaluating the effect of unsticking preparations on the survival of eggs to the eyespots, the highest survival was achieved with milk (71.9 +- 7.3 %). Statistically conclusively lower survival was found with tannin (47.4 +- 0.4 %) and acetylcysteine (48.4 +- 8.6 %). The achieved results can be used in artificial spawning of crucian carp as part of rescue breeding.
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Vliv teploty na schopnost oplození a líhnivosti při krátkodobém skladování neoplozených jiker síha peledě (Coregonus peled)
RYTÍŘ, Jan
The northern whitefish Coregonus peled (Gmelin, 1788), originally from Russia, was introduced to the Czech Republic in 1970 for its tasty meat and good growth ability. Breeding of this species has been very popular in the past. Currently, thanks to the fish-eating predators, traditional breeding of this species is on decline. The aim of this M. Sc. Thesis was to sumarize the avaible information in the field of peled biology, artificial propagation and also information about effect of temperature on the ability of fertilization and hatching for short-term of unfertilized eggs in other salmonid species. In the practical part, the influence of temperature and length of storage of stripped, unfertilized eggs of peled on fertilization, survival to eyed eggs and hatching were observed. Unfertilized eggs were divided into five bowls and deposited in thermo boxes, which were tempered to 2.5, 5, 7.5, 10 and 12.5 °C. After time intervals of 1, 4, 12, 24, 36, 48, 60 and 72 hours, approximately 100 - 200 eggs were taken from each thermobox, which were fertilized with fresh sperm (collected from several males) and water from the hatchery. The fertilized and purified eggs were moved to the incubators with continuously inflow of fresh water. Dead eggs were removed and recorded. Subsequently, fertilization, eyed eggs and hatching eggs were determined. The resulting values of these parameters were expressed as a percentage of the total number of used eggs. High levels of fertilization and survival to eyed eggs were achieved when stored within 1 day from eggs stripping at all temperatures except the highest temperature of 12.5 ° C. As the interval gradually lengthened, the fertilization and survival parameters also decreased, most notably at 7.5 and 10 ° C. To obtain the largest possible amount of fry in fishing practice, it is recommended to store eggs at 2.5 and 5 ° C, up to 48 hours after ova stripping. At higher temperatures, the effective storage time is reduced to 12 hours. Storing eggs for longer than 48 hours, in practical terms has no meaning. At the same time, it was found that at the above-mentioned optimal temperatures for storing eggs (2.5 and 5 ° C), the best hatching results were obtained when storing stripped eggs for 12 hours. Not only for longer, but also for shorter storage lengths, the values of this parameter were lower.
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Zhodnocení přežívání a růstu dvou invazivních raků v teplotně suboptimálních podmínkách
MARKOVÁ, Kateřina
Biological invasions of non-native species are one of the most serious threats negatively impairing global biodiversity. The negative influence of these invasions is especially noticeable in freshwater ecosystems also exemplified by the populations of native crayfish species in Europe. Dominance of non-native species of crayfish over native ones is relatively well known and studied, but the interactions between individual non-native invasive species are significantly less explored. As the range expansion and numbers of non-native crayfish species constantly increases, it becomes apparent that the non-native species will dominate in European waters. However, it is not clear which of these invasive species, and under which conditions will perform better. The goal of this bachelor thesis was to create a literature review focusing on factors that negatively influence the population of the native species (mainly the issue of non-native species and crayfish plague which these species often transmit). Consideration was paid to the importance of the water temperature for the crayfish and to the focused species used in the experimental part the marbled crayfish Procambarus virginalis Lyko, 2017 and signal crayfish Pacifastacus leniusculus Dana, 1852. The experiment was focused on the evaluation of survival, growth, damage to the claws, and the maturation of these species at the water temperature of ~16 °C, which is in the optimal range for signal crayfish, but suboptimal for marbled crayfish (yet, within a range presumably allowing its successful reproduction). If these species should meet more frequently in the wild, it is important to understand their relationships.
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Hlubší náhled do genetických a fenotypových korelací mezi kvantitativními znaky se vztahem k produkci u kapra obecného
ZHAO, Jinfeng
Selective breeding has large potential for genetic improvement of production traits in the aquaculture. However, basic knowledge is lacking about phenotypic and genetic parameters for economically important traits for development of selective breeding programs of common carp. Thus, genetic and phenotypic relationships of production-related quantitative traits were investigated in Amur mirror breed of common carp under the pond management condition. Growth is usually the first goal in breeding programs of different species. Selection for faster growth, may affect muscle fat content but the real change will depend on conditions and slaughter yields and it would not affect survival, susceptibility of fish to koi herpesvirus disease (KHVD). In addition, body weight should be integrated in a selection index to avoid a negative impact on growth when selecting for slaughter yields. Muscle fat content is a production trait playing an important role in biological functions of common carp. Muscle fat of common carp would indirectly increase in all subsequent periods by selection on higher body weight in all periods before the second winter. High muscle fat might not be the best for good overwintering in common carp due to negative genetic correlation between muscle fat content and survival during the second and third growing season and that selective breeding for restricted fat content may increase survival without affecting harvest weight. Survival is an important economic trait related to performance of common carp. Keeping excessive muscle fat, hepatopancreas (HP) fat and protein might be disadvantageous for carp survival, at least under conditions where ability of keeping higher level of HP glycogen and hepato-somatic index (HSI) is better. In addition, selection for higher Fulton's condition factor (FC) after the second overwintering should lead to slight increase of survival. KHVD is currently the most serious threat to global carp farming. Improvement of genetic resistance of carp strains through selection can be the most effective method. Most genetic correlations between KHVD resistance and important production traits (e.g., growth, muscle fat content, winter survival and energy reserves) were insignificant, showing that selective breeding program for important production traits would not affect the KHVD resistance of carp and vice versa. Selection for lower FC, relative head length, relative body height or relative body width, with a more prolonged body shape of Amur mirror carp being associated with higher KHVD resistance and selection for improved slaughter yields could positively affect resistance to KHVD and vice versa. Including FC into selection program of common carp could be advantageous for general fish vitality and performance but may have reverse effect on resistance of fish to KHVD. Slaughter yields are traits of high interest especially for fish species sold in processed form like headless carcass or fillet. Slaughter yields predicting models as well as some simple predictors in common carp recorded using combination of 3D landmarks and ultrasound imagery or ultrasound only were highly heritable and strongly genetically related to real yields and may be used in indirect selection program. Due to good genetic correlations between simple predictors in age of two and three years, selection of Amur mirror carp could be done at size of fish that requires less storage capacity and time. However, it should be remembered that selection for slaughter yields may affect body shape, muscle fat content and resistance of fish to KHVD.
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Inovace chovu larev candáta obecného (Sander lucioperca L.) při použití vířníků druhu Branchionus plicatilis
IMENTAI, Aiman
Pikeperch (Sander lucioperca L.) has been realized as one of the promising candidates. Currently one of the crucial bottlenecks in pikeperch larviculture is larval first feeding when high mortalities occur. Since recognition of rotifers as potential candidate for larvae culture, its value has grown tremendously in fish hatcheries. Although using rotifers and Artemia as a starter food items has become a common practice in hatcheries, yet rotifers has not been used for pikeperch larval culture. Many questions regarding introduction of rotifers during pikeperch larval first exogenous feeding are still not answered. The aim of this Ph.D. thesis was to maximize survival, growth and fitness of pikeperch larvae during first exogenous feeding by using rotifers Brachionus plicatilis. The effects of B. plicatilis on survival rate, growth performance and fitness of pikeperch larvae during first feeding were evaluated in the first study. Larvae were reared under three different diets (Artemia; Art /rot; rotifers) from 3 till 17 days post hatch (DPH). Using rotifers as first diet for pikeperch larvae was shown to benefit survival and growth rates. Larvae fed on rotifers only or combined diet (rot/Art) obtained higher survival and growth compared to Artemia diet. It was found that essential fatty acids of rotifers and their smaller size had a crucial effect on the larval survival and performance. The findings of the first study showed that the mixed diet (rot/Art) could be recommended as innovated first exogenous feeding in pikeperch larvae. The objective of the second study was to optimize the first exogenous feeding regime for pikeperch larvae using rotifers and Artemia. Larvae were fed with rotifers for 3 days and afterwards from 8 to 17 DPH they were adopted to 5 different regimes. It was found that feeding pikeperch with rotifers from 5 to 8 DPH and afterwards exclusively with Artemia or mixed of rotifers and Artemia till 17 DPH can ensure high survival and growth rates, and better development of digestive organs. Feeding larvae with rotifers from 5 to 8 DPH and afterwards replacing with Artemia till 17 DPH is recommended as an optimum feeding regime because larval survival and growth were satisfying, and it reduces the costs for production. The main aim of the third study was to determine the optimal salinity for rearing of pikeperch larvae using B. plicatilis. Rotifers were stocked under different salinities and motility was investigated over a 6-h period. The same salinities were used in second trial of this study to quantify the effect on pikeperch gut fullness over the course of 11 h. In the third trail, the survival and growth rate of larvae from 4 to 11 DPH at low and medium salinities were analyzed. Results of this study showed that rotifers stocked at all tested salinities, except for freshwater retained motility for over a 6-h period. Pikeperch larvae reared at 2? and 4 ? showed higher survival and growth rate during trial compared to freshwater. The results of this study showed that larvae in low salinity water had higher survival and growth rate during initial exogenous feeding with B. plicatilis. The aim of fourth study was to determine the optimal rotifers density for pikeperch larvae at the beginning of exogenous feeding. Larvae were divided into 4 groups at different rotifers densities from 5 to 9 DPH. The best growth performance was achieved at the highest rotifers density, however survival rate did not significantly differ among the groups. The results suggested that B. plicatilis at density of 6 ind/mL can be considered optimal for larval growth from 5 to 9 DPH when balancing production and costs, compared to higher prey densities.
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