In terms of section 186(1)(e) of the Labour Relations Act 66 of 1995 constructive dismissal occurs where an employee terminated a contract of employment with or without notice because the employer made continued employment intolerable. Work stress is becoming more and more imminent in the workplace. Some employees feel that the amount of work stress also makes their continued employment intolerable, and then they claim constructive dismissal. This raises the question whether the courts should apply the same tests they apply in constructive dismissal cases as well as in cases where the employee resigns because of work stress. But, if the same tests that are used to determine if there has been a constructive dismissal are used in a case where an employee resigns because of work stress, a real danger exists because then it can lead to the misuse of a claim of constructive dismissal by employees who cannot handle a minimum amount of work stress. Over the years the courts have indicated that they apply an objective test in cases of constructive dismissal. This leads to the argument whether subjectivity should play a role, and whether one should look at the subjective perspective of both the employer and the employee. This research looks at numerous court decisions, from both the South African legal system as well as the United Kingdom legal system, in order to determine which tests the South African courts need to apply when they are confronted with a constructive dismissal claim where the employee resigned due to work stress. Constructive dismissal – resignation – work stress – stress due to an excessive workload – work stress and employee wellness – stress based claims. / Thesis (LL.M. (Labour Law))--North-West University, Potchefstroom Campus, 2011

The author deals with oxidative stress and its effects on the pathogenesis of various diseases including the development of insulin resistance. The work is divided in the usual way overview of current knowledge on the issues, methods, results, discussion and conclusions. Part of this work is to describe an animal experiment in the waking state, whose introduction to our department was one of the tasks of this graduate work.

The vast majority of exogenous substances is metabolized in the liver. In the course of the biotransformation, partly biologically non-active products, partly reactive species leading to cell structure injury and even to the liver failure are produced. Oxidative stress plays a significant role in the toxic- and drug-induced liver damage. Endogenous and exogenous antioxidants contribute to equilibrium between the production and the elimination of reactive oxygen species and thus prevent the oxidative stress. In acute experiments in rats we examined the ability of natural antioxidants silymarin, naringin and resveratrol and of synthetic chelator deferipron to protect against liver damage induced by paracetamol, thioacetamide and tamoxifen. The following parameters of oxidative stress were measured in the liver homogenates: level of lipid peroxidation (LP), concentration of reduced glutathione (GSH), activities of glutathione peroxidase (GPx) and of catalase (CAT); in some cases the iron liver content. The following markers of liver damage were measured in serum: alanine aminotransferase (ALT), aspartate aminotransferase (AST), glutamate dehydrogenase (GLDH). Concernig markers of oxidative status, silymarin exerted the most efficient antioxidant properties amelioratig the TAA- and TAM-induced lipid...

Within the span of few decades, there has been a significant increase in diabetes mellitus and chronic stress in developed countries, such as the Czech Republic. These conditions have a significant negative effect on physical and mental health. Repeated and long-term exposure to raised levels of glucose, overactivity of the sympathetic nervous system and the increase in plasma levels of stress hormones affects most of the organs in the body, including the heart. The cardiovascular system is regulated by a broad number of neurotransmitters, hormones and neuropeptides. Alterations in the innervation of the cardiovascular system, as a result of both diseases, can affect its physiological functions. The present thesis focuses not only on the role of the classic, but primarily on the peptidergic innervation of the heart. The aim was to contribute to the explanation of the impact of neuropeptides and their shared receptor systems on the genesis and the development of heart damage due to diabetes mellitus and/or exposure to stressors. Knowledge of the physiological characteristics of neuropeptides and their involvement in the pathogenesis of both diseases and related complications could be helpful in determining the optimal treatment method or alternatively allow us to use the cardio protective effect of...

The main objective of this Diploma Thesis is to determine effects of endurance running on body weight reduction of men within the age group between 35 and 45 years young middle age. The theoretical part revealed interesting facts and compilations provided by various available resources related to the given issue and thus served as a basis for the elaboration of the practical part consisting in heart rate values obtained during several hours of endurance run. The impact on health of probands (tested men) was discovered while assessing heart rate, BMI values and anthropometric measurements of four skin-fold thickness by using skinfold calipers. The result revealed considerable reduction in body fat percentage rate as a consequence of endurance running which was proved as a convenient and recommended activity bringing many benefits to human health, such as reducing overweight of men within the aforementioned age group.

Oxidative stress is caused by an imbalance between high production of reactive oxygen species and ability of organism to detoxify them or counteract their effects. The chromosomal ends telomeres - are specialized nucleoprotein structures protecting chromosome ends from DNA damage. Telomeres of Drosophila melanogaster are arrays of specific non-long terminal repeated (LTR) retrotransposons HeT-A, TART and TAHRE. This thesis evaluates effects of exposure of paraquat, which is a strong oxidative stress inducer, on telomere length and transcription activity in Drosophila.

The main objective of this study was to determine the effect of elevated CO2 and drought on growth of fast-growing trees, hence hybrids of poplar Populus nigra and Populus maximowiczii on experimental station Domanínek. These parameters were measured: photosynthesis, reflectance, fluorescence of chlorophyll and content of chlorophylls and flavonols. The results show a demonstrable effect of greater regulatory abilities stomatas at elevated CO2 concentration, which leads to greater efficiency of water use. Decisive influence on leaf area, specific leaf area and the dry weight has the effect of drought. However, for specific leaf area, contrary to expectations, there was an noticeable increase during drought period. In the case of other characteristics come to reduce them. By contrast specific leaf area slightly decreases at elevated CO2 concentration. Rate of photosynthesis increases with increasing concentrations of CO2, while the effect of drought dampens these characteristics and also reduces the chlorophyll content. Increasing concentration of CO2 during the experiment also leds to an increase in NDVI index, which shows increased chlorophyll content. The values of fluorescence at two concentrations of CO2 when exposed to drought stress differed minimally. The maximum quantum yield of photosystem II is slightly higher at elevated CO2 concentration. Overall, it can be summarized that in the short-term effect of drought stress in hybrid poplar, increased concentration of CO2 increases water use efficiency and thus to mitigate the impact of drought on photosynthetic parameters.

Spermatozoa of externally fertilizing fish species after releasing into aqueous environment are particularly vulnerable to damage mainly due to alterations in composition of media surrounding sperm. Among factors affecting spermatozoa movement in external medium are water pollutants, temperature, pH and osmotic conditions. The goal of this thesis was to investigate the possible effects of oxidative stress on sperm performance and intracellular signaling, particularly the effect of pollutants occurring in water environment. In addition the molecular mechanisms of stress response and motility activation for spermatozoa of several freshwater fish species were analyzed. Our results show that xenobiotics, such as vinclozolin, induce a dose-dependent reduction in sterlet (Acipenser ruthenus) spermatozoa motility and velocity at environmentally relevant concentrations. Increased levels of lipid oxidation (LO) and protein carbonylation (CP), as well as changes in antioxidant activity of superoxide dismutase (SOD) indicate the development of an oxidative stress in spermatozoa exposed to xenobiotic. Moreover, increased DNA fragmentation as well as a reduction of the level of ATP was observed in spermatozoa incubated with xenobiotic in vitro. These results demonstrated that sterlet spermatozoa are highly susceptible to the presence of pollutants, which induce excessive ROS production even at low concentrations. Further studies were performed in order to evaluate the role of ROS production in fish sperm and protective properties of seminal plasma. The ROS were generated in carp (Cyprinus carpio L.) spermatozoa by in vitro incubation with xanthine - xanthine oxidase system (X-XO). A time- and dose-dependent reduction in spermatozoa motility and velocity was observed as well as increased LO, CP and DNA fragmentation. Moreover, it was shown that O-linked N-acetylglucosamine transferase and septin-8-A changed their phosphorylation state on tyrosine residue, and acid phosphatase activity decreased in response to oxidative stress. On the other hand, catalase (CAT), superoxide dismutase (SOD), and glutathione (GTH) in combination with seminal plasma can reduce oxidative stress in carp spermatozoa and improve sperm quality. Our next study was applied to determine how the protein phosphorylation pattern changed after motility activation in carp and sterlet spermatozoa, where phosphorylated proteins are located in spermatozoon and to identify proteins involved in sperm motility. It was shown that the pattern of protein phosphorylation and their localization differs significantly between two species. Phosphorylation on serine and tyrosine residues, as well as protein kinase A (PKA) and protein kinase C (PKC) substrates play an important role in spermatozoa motility activation and regulation in both species. Numerous signaling proteins involved in carp and sterlet spermatozoa movement were identified in this study, giving a better understanding of molecular mechanisms underlying sperm motility. As a conclusion, the results of this study provide new data on the effect of xenobiotics and oxidative stress on fish spermatozoa motility, DNA integrity, lipid and protein oxidation, antioxidant defense system and intracellular signaling. These data proved the toxicity of water pollutants and ROS for fish spermatozoa and proposed the use of CAT, SOD, or GTH in combination with seminal plasma to reduce oxidative stress in these cells. Moreover, we identified many spermatozoa proteins involved in stress response and motility. In practice, the data presented in this thesis could be useful for elaboration of suitable medium for cryopreservation and artificial propagation of freshwater fish species.

Drought is considered as one of the most important abiotic stress factor, which can cause a severe impact on agriculture. The development of new cultivars of barley is therefore more focused on improving of abiotic stress tolerance to drought, as well as on maintaining of good health status, appropriate yield levels and quality parameters. This work was aimed at evaluation of barley cv. Tadmor, which is specifically adapted to drought and can be potentially used as a source of drought tolerance in barley breeding programmes. F5 generation lines derived from reciprocal crosses between cv. Tadmor and cv. Jersey (advanced European spring malting barley) together with parent cultivars were cultivated at two sites (Brno, Žabčice). The assessment was aimed at traits associated with yield (thousand grain weight - TGW, percentage of sieving fraction over 2.0 mm, grain yield per plant) and quality (protein and starch content). The effect of water-limited conditions at Žabčice site was demonstrated particularly in the TGW and the percentage of sieving fraction over 2.0 mm, while the lines from Tadmor x Jersey cross sustained the stress significantly better than those from Jersey x Tadmor cross. The lines grown in Žabčice reached in average a higher level of protein content and a lower level of starch content. The significant effect of genotype was detected only in protein content and was non-significant for starch. The reaction of selected lines on osmotic stress was studied in and independent experiment under controlled conditions. The plant stress reaction was evaluated according to changes in osmotic potential in leaves and accumulation of proline. Lines with Tadmor as a female parent showed higher values of osmotic potential in comparison with those derived from the reciprocal cross. The increase in osmotic potential under stress was strongly associated with the content of proline. The last part was focused on evaluation of susceptibility to powdery mildew caused by Blumeria graminis. The symptoms of powdery mildew on experimental lines were assessed in field and the lines, which were classified as resistant/susceptible, were further analysed for the presence of mlo allele. According to the results all resistant lines carried mlo9. With regard to all evaluated parameters, positive reaction on physiological drought stress and genetically controlled resistance against powdery mildew two lines can be recommended for further work.

Annotation This diploma thesis deals with the issue of burnout syndrome among high school teachers. The introductory theoretical part characterizes terms burnout and stress which is closely connected with burnout. This thesis also focuses on reasons of burnout, its phases, risk factors and prevention. Following part focuses on the teaching profession in connection with burnout. In the practical part there are analyzed data acquired from questionnaires. The aim was to find out to what extent teachers feel signs of burnout in four levels (cognitive, affective, physical and social) from the point of view of gender and the length of experience.