Objetivo: Comparar in vitro la degradación de fuerzas de tensión de los elásticos intermaxilares de látex y no látex DentsplyTM GAC de 5/16" (8mm) y 6oz (170g) expuestos y no expuestos a alimentos de consumo diario sometidos a dos tiempos de evaluación. Materiales y métodos: El estudio fue experimental in vitro. Se utilizó 136 elásticos intermaxilares de látex y no látex DentsplyTM GAC 5/16" (8mm) y 6oz (170g). Se dividieron en 4 grupos de 34 elásticos (Grupo A: Látex-agua destilada, Grupo B: No látex-agua destilada, Grupo C: Látex-comida diaria, Grupo D: No látex-comida diaria). Los gupos A y B fueron sumergidos en agua destilada a 37ºC, mientras que los grupos C y D fueron sumergidos a una dieta que se realizó en cuatro momentos (0, 3, 6 y 12 horas). A todos los grupos se le evaluó la fuerza de tensión a las 0 y 24 horas con la máquina Instron®(1mm/s). Los valores fueron registrados en Newtons (N). Resultados: Se encontraron diferencias estadísticamente significativas (p= 0,000) en el porcentaje de degradación de los elásticos intermaxilares de látex y de no látex DentsplyTM GAC. En valores porcentuales la degradación de los elásticos de látex fue 28.65% y los elásticos de no látex 38.47%. Sin embargo, al evaluar la degradación de los elásticos según la exposición a alimentos no se encontró diferencia estadísticamente significativa (p0.05). Conclusiones: En este estudio, se encontró mayor degradación de los elásticos de no látex. Por otro lado, a pesar de que los elásticos DentsplyTM GAC se expusieron a una dieta diaria, no existió mayor degradación. / Objective: To compare in vitro the degradation of tensile forces of latex intermaxillary elastics and non-latex DentsplyTM GAC 5/16 "(8mm) and 6 oz (170g) exposed and not exposed to daily consumption food subjected to two times of evaluation. Materials and methods: The study was experimental in vitro. It was used 136 intermaxillary elastics of latex and not latex DentsplyTM GAC of 5/16 "(8mm) and 6oz (170g). They were divided into 4 groups of 34 elastics (Group A: Latex – distilled water, Group B: Non-latex - distilled water, Group C: Latex - daily food, Group D: Non-latex - daily food). Groups A and B were submerged in distilled water at 37ºC, while groups C and D were submerged in a diet that was performed in four moments (0, 3, 6 and 12 hours). All the groups were evaluated the tensile strength at 0 and 24 hours with the Instron® machine (1mm/s). The values were recorded in Newtons (N). Results: Statistically significant differences (p = 0.000) were found in the percentage of degradation of the intermaxillary elastics of latex and non-latex DentsplyTM GAC. In percentage values the degradation of the elastics of latex was 28.65% and the elastics of non-latex 38.47%. However, when evaluating the degradation of the elastics according to food exposure, no statistically significant difference was found (p0.05) Conclusions: In this study, greater force degradation of non-latex elastics was found. On the other hand, although the Dentsply ™ GAC elastics were exposed to a daily diet, there was no further degradation. / Tesis

This study aimed to evaluate otter predation on stocked trout and grayling. The diet composition of piscivorous Eurasian otters (Lutra lutra) was studied on the stream Chotýšanka in central Bohemia using spraint (otter faeces) analysis during one winter period (90 days). Stocking took place mostly in the second half of 2005. Around 5000 hatchery-reared brown trouts (Salmo trutta m. fario) of size about 10 cm, 600 graylings (Thymallus thymallus) of the same size and 480 rainbow trouts (Oncorhynchus mykiss) of size about 30 cm were stocked into the stream. Spraints were collected in December 2005 and January 2006. We found and identified 1531 fish in the spraints. The primary food source of otters was fish (almost 85 % of biomass). The main fish prey was small - sized, below 20 g in weight and 13 cm in length. The bulk of otter's diet consisted of less - valued species, especially the gudgeon (Gobio gobio). Other frequently consumed fish species were the European chub (Squalius cephalus), the common carp (Cyprinus carpio), the European perch (Perca fluviatilis), the brown trout and the rainbow trout. Consumption of stocked brown trout was 1,80 %, while cosumption of stocked rainbow trout was 10,90 % of biomass. Otters in this area consumed about 723 - 1446 brown trouts and 72 - 144 rainbow trouts...

vi Abstract Continental subspecies of the great cormorant (Phalacrocorax carbo sinensis) is the Czech Republic's most important fish-eating predator. It causes damage to production fish, as well as sport fishermen and even after its removal from the Czech list of endangered species in 2013, it did not disappear from the spotlight of both local fishermen and researchers. This thesis evaluates the qualitative and quantitative composition of the cormorant's diet during winter 2011/2012 at two selected locations: the Žehuň pond (Kolín district) and Berounka river in the natural reserve Zábělá near Pilsen. This work studies the main components of cormorant's diet in the selected locations and evaluates potential fluctuations and changes in its composition during winter. The study also conducted the analysis of the proportion of commercially harvested valuable fish in cormorant's diet and studied its diversity of the species spectrum. The resulting data for the two sites were compared with each other and with relevant literature. Regurgitated pellets analysis, as well as analysis of diagnostic bones and fish remains located at the sleeping roosts (night roosts) were used for the diet analysis. It was found that at both sites roach was the most caught fish, but from the point of view of total biomass, it was...