Climate change is expected to have a strong impact on subarctic ecosystems. Increased temperatures as well as altered precipitation and snow cover patterns are predicted to change species distribution and affect biogeochemical processes in the subarctic tundra. Bryophytes are an essential vegetational component in northern ecosystems, due to their high abundance and importance in many ecological processes. In this study the effects of elevation and altered snow cover on the temporal dynamics of freezing damage in three subarctic bryophyte species (Hylocomium splendens, Ptilidium ciliare, and Sphagnum fuscum) were studied in a snow manipulation field experiment in Abisko, during early spring. Soil temperature and field moisture of moss shoots were collected. A freeze-thaw incubation experiment was conducted to investigate the freeze-thaw cycle resistance of H. splendens and P. ciliare originating from habitats with two differing snow-cover thicknesses. Freezing damage differed significantly between the bryophytes species with P. ciliare experiencing the least and S. fuscum the highest damage. Damage was higher at the low elevation, possibly attributable to acclimation effects. Snow removal led to higher damage in moss shoots, but no interactions of the different snow cover treatments with elevation, species or time were found. Freezing damage increased over time and no recovery occurred, likely due to temporal patterns in soil freeze-thaw cycles during early spring. Soil freeze-thaw cycles were the main factor influencing damage in bryophytes after snow melt. Measured environmental parameters could not explain the entire variation in damage. Damage might additionally be attributable to increased UV radiation or disturbances by herbivores.

This thesis is concerned with the effects of radiation damage in CCDs used for space applications. The manufacturing process and operational principles of CCDs are presented in Chapter 2. The components of the space radiation environment, the two radiation damage mechanisms relevant to CCDs, and the effects of radiation on the operational characteristics of CCDs are described in Chapter 3. Chapter 4 presents a study to assess the suitability of novel L3Vision technology to applications in space. Two L3Vision CCDs were subjected to proton irradiations representative of doses expected to be received by spacecraft in low Earth orbit. Post-irradiation the devices were found to operate as expected, the effects of radiation on the operational characteristics of the devices being comparable to previous studies. The effect of low energy protons on CCDs is the subject of Chapter 5. The study was initiated in response to the finding that soft protons could be focused by the mirror modules of the XMM-Newton spacecraft onto the EPIC CCD detectors. Two EPIC devices were irradiated with protons of a few keV to find that soft protons cause more damage than that expected by the NIEL damage relationship, as they deposit most of their energy within the CCD. The observed change in CTI of the EPIC devices on XMM-Newton is however comparable to the pre-launch prediction, and the component attributable to low energy protons is small, < 20%. Chapter 6 presents a study of a specific radiation induced phenomenon, `Random Telegraph Signals'. Development of analysis software and the irradiation of two CCDs are discussed before a detailed characterisation of the generated RTS pixels is presented. The study shows that the mechanism behind RTS involves a bi-stable defect linked with the E-centre, in combination with the high field regions of a CCD pixel.

ABSTRACT DNA in the eukaryotic nucleus is complexed with histone and non-histone proteins into chromatin. Nucleosomes, the basic repeating unit of chromatin, not only package DNA but are also intimately involved the regulation of gene expression. All DNA transactions including replication, transcription, recombination and repair take place in such a chromatin environment. Access to packaged nucleosomal DNA in vivo is mediated at least in part by protein complexes that modify or remodel chromatin. Buried sequences in nucleosomes can also transiently become accessible to DNA binding proteins during cycles of partial, reversible unwrapping of nucleosomal DNA from the histone octamer. We have investigated the ability of the human, bifunctional DNA glycosylase, endonuclease III (hNTH1), to initiate base excision repair (BER) of discretely positioned oxidative lesions in model nucleosomes. hNTH1 was able to process a thymine glycol (Tg) lesion almost as efficiently as naked DNA, when the minor groove of the lesion faced away from the histone octamer. Lesion processing did not require or result in detectable nucleosome disruption, as assayed in gel mobility-shift experiments. Instead, hNTH1 formed a slower migrating enzyme-nucleosome ternary complex that was found to contain processed DNA. Processing of an inward-facing Tg residue located just 5 bp away from the outward-facing lesion was much reduced and processing of a sterically occluded Tg residue positioned closer to the dyad center of the nucleosome was even more reduced. Notably, processing of both inward-facing lesions was found to increase as a function of enzyme concentration. Restriction enzyme protection studies indicated that access to these inward-facing lesions did not entail nucleosomal translocation or sliding. Collectively, these observations are consistent with a model in which hNTH1 binds to lesions during cycles of reversible, partial unwrapping of nucleosomal DNA from the histone octamer core. To further investigate this partial unwrapping hypothesis, we studied the kinetics of hNTH1 processing of sterically occluded lesions in greater detail. Our results suggest that efficiency of processing of inward-facing lesions is a function of both DNA unwrapping and rewrapping rates, and enzyme affinity for the lesion. In addition, we determined that APE1 which catalyzes the second step in BER, exhibited an increasing capacity to process inward-facing furan residues as its concentration was increased. Thus as with hNTH1, we hypothesize that APE1 can capture occluded furan residues during cycles of partial DNA unwrapping. We propose that cellular regulatory factors benefit from this intrinsic, periodic exposure of nucleosomal DNA exposure in vivo, which may be amplified by the downstream recruitment of remodeling and / or modifying proteins to facilitate DNA transactions in the cell.

L'utilisation de limiteurs de localisation est nécessaire pour prendre en compte l'apparition de macro-fissures lors de la simulation de l'évolution des dégradations dans les matériaux composites stratifiés en accord avec des expérimentations. Ceux-ci introduisent un paramètre qui peut être relié à une longueur, ou un temps caractéristique, qui peut alors être identifié. L'approche introduite au LMT-Cachan consiste, dans le cadre dynamique, à utiliser un modèle d'endommagement retardé. Elle est basée sur le fait qu'une fissure ne peut pas apparaître instantanément. Ce modèle donne d'excellents résultats en restant dans le cadre de la dynamique et a l'avantage d'être local en espace. Cependant il requiert une discrétisation temporelle de la taille du temps caractéristique introduit (de l'ordre de la microseconde pour les composites), qui le rend inexploitable pour des simulations de chargement en quasi-statique. Les simulations dans ces cas de chargement nécessitent donc l'utilisation d'un temps caractéristique différent de celui identifié qui ne permet plus de maintenir un résultat en accord avec l'expérience. On cherche alors à adapter les paramètres de la loi d'évolution de l'endommagement afin d'obtenir une propagation de la macro-fissure dans la zone localisée qui soit compatible énergétiquement avec la mécanique de la rupture en contrôlant le taux de restitution d'énergie. Ce travail est dédié à maintenir l'objectivité de la solution et à adapter l'énergie dissipé à la mécanique de la rupture afin de pouvoir utiliser un temps caractéristique exploitable lors de simulations d'éprouvettes en composites sous un chargement quasi-statique. / The use of localization limiters is needed to take into account the apparition of macro-cracks during the simulation of the evolution of degradations in laminated composite materials with respect to experiments. Those introduce a parameter which can be related to a characteristic length, or a characteristic time, and therefore be identified. The approach introduced at LMT-Cachan is, in dynamics, to use a delayed damage model. It's based on the fact that a crack can't appear instantaneously. This model gives excellent results in dynamics and has the advantage to be local in space. Unfortunately, it requires a time discretization related to the characteristic time introduced (of the order of a microsecond for composites), which is far too computationally expensive for quasi-static simulations. Simulations in these loading cases need the use of a different characteristic time from the one identified which can't maintain anymore a result in accordance to experiments. We then adapt the parameters of the damage evolution law to obtain a propagation of a macro-crack in the localized zone that is energetically compatible with fracture mechanics by controlling the strain energy release rate. This work is dedicated to maintain the objectivity of the solution and to adapt the dissipated energy to fracture mechanics to be able to use a characteristic time exploitable for the simulation of composite samples under quasi-static loading.

This paper deals with the operators responsibility for damage caused by a motor vehicle in the current Civil Code and the new Civil Code, which will be effective from 1. 1. 2014. According to the always-study of the topic immediately point out the specific changes that occur due to the new regulation. The first chapter deals with the importance of explaining the issue of damages in a social context. Furthermore, I point out its functions. The second chapter deals with the definition of basic concepts related to this problem. Define who or what is motor vehicle damage and operator. Interpret different kinds of operators of vehicles, when their resolution is critical consequences for the operator is obliged to pay damages. The third chapter explains the general provisions on liability for damage. It also deals with the inclusion of liability in the Code civil law. The fourth chapter deals with a thorough explanation then specific responsibility for damage caused by vehicles. Interprets the scope of this responsibility, the possibilities of the operator himself from the obligation to pay compensation and liability insurance for damage caused by the operation of motor vehicles. The fifth chapter is intended to familiarize the reader with the possibilities of compensation methods, the content of...

People encounter civil relationships in everyday life, thus the civil law follows a human being from his/her birth to death. Obligation relationships can arise not only at the basis of law actions, predominantly contracts, but also from illegal actions and by law qualified events, which lead to an origin of damages or a defect in an object of fulfilment. Both, liability for damage and liability for defects represent significant part of civil law and belong among the most discussed problems in law theory. The aim of this thesis is to focus on mutual relationship between liability for damage and liability for defects according to the Act No. 40/1964 LC., civil legal code, and to present important terms with a consideration of a rich judicature in this area. Some of the differences between liability for damage and liability for defects according to the Act No. 513/1991 LC. are explained briefly; since the commercial law modification would deserve a separate thesis. This thesis consists of six chapters which are further separated into individual subchapters. The first chapter is dedicated to the liability in general and its law- theoretical explanation and specification of the term civil liability. The second chapter called "Prevention of damages in civil relationships" tells about prevention of origin...

The eukaryotic cell cycle is governed by molecular checkpoints that ensure genomic integrity and the faithful transmission of chromosomes to daughter cells. They inhibit the cycle until conditions prevail that guarantee accurate DNA duplication and chromosome segregation. Two major mechanisms are the ‘spindle assembly checkpoint’ and the ‘DNA damage checkpoint’. During pro-metaphase, the spindle checkpoint monitors the orientation process of chromatid pairs on the bipolar microtubule array nucleated by spindle pole bodies. In the yeasts Schizosaccharomyces pombe and Saccharomyces cerevisiae, six proteins are at the heart of spindle checkpoint function: Mad1, Mad2, Mad3, Bub1, Bub3 and Mph1/Mps1. The formation of spindle checkpoint complexes signals the presence of incorrect spindle microtubule attachments to kinetochores. These complexes cooperate to suppress the activity of the anaphase promoting complex (APC) and inhibit the onset of anaphase. By isolating these distinct complexes and analysing their composition by mass-spectrometry (MS) this work revealed several intriguing disparities between the two yeast species, and the way in which the Bub and Mad proteins cooperate to achieve inhibition. The ‘mitotic checkpoint complex’, which in S.cerevisiae consists of Mad2, Mad3, Bub3 and the APC activator Cdc20, was found to lack Bub3 in S.pombe. The S.pombe complex was shown to interact with the APC, but no stable interaction was found to be required in S.cerevisiae cells. And whereas Bub1 and Bub3 were found to form a complex with Mad1 in S.cerevisiae, in S.pombe they were shown to associate with Mad3 to form the ‘BUB+ spindle checkpoint complex’. In addition, MS analysis uncovered TAPAS: a novel S.pombe complex that was found to interact with the BUB+ complex and revealed to consist of Tfg3, Abo1 (gene product of SPAC31G5.19), Pob3 and Spt16. TAPAS mutant cells were shown to lose viability as a result of genotoxic stress, a phenotype that was surprisingly shared with bub1Δ and bub1kd ‘kinase dead’ mutants. Sensitivity of cells deficient in TAPAS or Bub1 did not appear to be due to the loss of DNA damage checkpoint or DNA replication checkpoint functions. Further examination revealed that Bub1 functions in the repair of DNA double strand breaks. Taken together, this work demonstrates that even though the molecular components of the spindle checkpoint pathway are conserved, their regulatory connections have to some extent diverged through molecular evolution. This process not only rewired, but entwined two molecular processes that together safeguard the genetic heritage of cells.

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The overall aim of this thesis was to assess the potential of developing specific quantifiable assays of pollutant damage based on changes on the in vivo optical properties of macroalgae, applicable to laboratory and remote systems. The green macroalgae, E. intestinalis, was exposed to selected trace metals (copper and zinc), triazine herbicides (Irgarol 1051 and atrazine) and a series of alcohols (n =1- 9). The algal in vivo spectral properties, measured using a spectrophotometer fitted with an integrating sphere, determined changes due to exposure, and results were compared with established methods, including growth and fluorescence, to assess algal health status. Each pollutant, except zinc, had a significant (P &lt; 0.05) effect on in vivo spectral properties at the range of concentrations used. The results indicated that the technique has potential to identify the algal systems affected by the pollutant, as signatures obtained appeared to indicate whether change was due to structure or pigments. The technique was sensitive, repeatable, and could detect individual pollutants in a copper/Irgarol 1051 mixture. The results were mathematically interpreted to provide ratios, individual wavelengths, sensitivity figures, web diagrams and QSARs to highlight differences between pollutant effect. The QSAR, obtained from Eintestinalis exposed to a series of alcohols, had a R2 value of 0.9682 using in vivo absorptance at 680 nm and Log Kow, which corresponds with published values of 0.97 using ion leakage with the same species. However, the technique of in vivo spectral properties has the advantage of being non-invasive. Samples of E. intestinalis were collected from different field sites and their in vivo spectral responses could be grouped according to potential pollutants to which they had been exposed. In addition, the potential of extending the technique for use in remote sensing is discussed. It was concluded that the technique of monitoring in vivo spectral properties is an appropriate biomonitor to add to the expanding range of current biomonitors.