No description available.

In order to investigate the two-phase flow behaviour in a complex reactor-typical geometry and to supply suitable data for CFD code validation, a model of the hot leg of a pressurised water reactor was built at FZD. The hot leg model is operated in the pressure chamber of the TOPFLOW test facility, which is used to perform high-pressure experiments under pressure equilibrium with the inside atmosphere of the chamber. This technique makes it possible to visualise the two-phase flow through large windows, also at reactor-typical pressure levels. In order to optimise the optical observation possibilities, the test section was designed with a rectangular cross-section. Experiments were performed with air and water at 1.5 and 3.0 bar at room temperature as well as with steam and water at 15, 30 and 50 bar and the corresponding saturation temperature (i.e. up to 264°C). The total of 194 runs are divided into 4 types of experiments covering stationary co-current flow, counter-current flow, flow without water circulation and transient counter-current flow limitation (CCFL) experiments. This report provides a detailed documentation of the experiments including information on the experimental setup, experimental procedure, test matrix and on the calibration of the measuring devices. The available data is described and data sheets were arranged for each experiment in order to give an overview of the most important parameters. For the cocurrent flow experiments, water level histograms were arranged and used to characterise the flow in the hot leg. In fact, the form of the probability distribution was found to be sensitive to the boundary conditions and, therefore, is useful for the CFD comparison. Furthermore, the flooding characteristics of the hot leg model plotted in terms of the classical Wallis parameter or Kutateladze number were found to fail to properly correlate the data of the air/water and steam/water series. Therefore, a modified Wallis parameter is proposed, which takes the effect of viscosity into account.

Transposable elements (TEs) have had immense impact on the structure, function and evolution of eukaryotic genomes. The work in this thesis identified Kat1, a novel domesticated DNA transposase of the hAT family in the yeast Kluyveromyces lactis. Kat1 triggers a genome rearrangement that results in a switch of mating type from MATa to MATα. Furthermore, Kat1 acts on sequences that presumably are ancient remnants of a long-lost transposable element. Therefore, Kat1 provides a remarkable example of the intricate relationship between transposable elements and their hosts. We showed that Kat1 generates two DNA double strand breaks (DSBs) in MATa and that the DDE motif and several other conserved amino acid residues are important for Kat1 cleavage activity. DNA hairpins were formed on one end of the DSBs whereas the DNA between the DSBs was joined into a circle. Kat1 was transcriptionally activated by nutrient limitation through the transcription factor Mts1 and negatively regulated by translational frameshifting. In conclusion, Kat1 is a highly regulated domesticated transposase that induces sexual differentiation.  In another study, we developed an assay to measure switching rates in K. lactis and found that the switching rate was ~6x10-4 events/generation. In a genetic screen for mutations that increased mating-type switching, we found mutations in the RAS1 gene. The small GTPase Ras1 regulates cellular cyclic AMP levels and we demonstrated that Mts1 transcription is regulated by the RAS/cAMP pathway and the transcription factor Msn2. Since Ras activity is regulated by nutrient availability, these data likely explains why nutrient limitation induces mating-type switching.

As water stresses increase across the U.S., interest in household water reuse is growing. Such reuse typically focuses on light greywater, that is all wastewater generated in the house excluding toilet waste and kitchen wastewater. As this practice becomes more widespread, higher level reuse is expected to require greater greywater treatment prior to reuse. Membrane bioreactors (MBRs) are an attractive technology for this application because they offer a robust combination of treatment processes and are already used in some households in countries such as Japan. This research sought to understand the role of phosphorus availability in determining the quality of effluent from MBR treatment of light greywater because phosphorus concentrations are expected to be low with phosphorus phased out of many consumer products. Less than 30 [mu]g/L of dissolved orthophosphate was present in synthetic greywater made from three common household products, and no measurable amount of dissolved orthophosphate was found in real greywater, but low concentrations of particulate phosphate were detected. These concentrations were well below levels believed necessary to achieve full BOD₅ removal in biological treatment. Nevertheless, MBR performance was not adversely affected until no supplemental phosphorus was provided. Measurement of extracellular enzyme activity showed an increase in the ratio of phosphatase activity to total glycosidase activity with declining phosphorus concentration, providing an early indication of nutrient stress before changes in effluent water quality were detected. Removal of three xenobiotic organic compounds (XOCs) in treatment of synthetic greywater was also evaluated under conditions of phosphorous limitation and balance. Abiotic removal mechanisms were not deemed to be important, but removal of methylparaben and sodium lauryl sulfate via biodegradation responded to nutrient limitation similarly to overall COD removal while removal of diethyl phthalate was affected to a greater extent. Measurement of plasmid DNA concentrations was evaluated as a potential indicator of the effect of nutrient limitation on plasmid-mediated biodegradation of XOCs. An overall reduction in the plasmid content was observed in all cases under conditions of phosphorus limitation; however, the extent of reduction was reactor dependent. / text

The southwestern Florida shelf marine environment has often been characterized as oligotrophic, yet these waters can support large, high biomass, persistent phytoplankton blooms, including blooms of the toxin producing dinoflagellate Karenia brevis. Little is known regarding which major nutrient potentially limits primary production in these waters as both inorganic nitrogen and phosphorus concentrations are often near the limits of analytical detection and it is difficult to estimate what percentage of the dissolved organic pool is available for phytoplankton uptake. To assess the nutrient status of phytoplankton populations on the southwest Florida shelf, this project examines the particulate nutrient stoichiometry of ambient phytoplankton assemblages from 1998-2000 as part of the ECOHAB: Florida Program. Particulate C, N, P concentrations and particulate ratios display a large range of values across the West Florida Shelf (WFS). The average particulate stoichiometry is well above the classic Redfield ratio with a geometric mean of 410C:56N:1P. Frequency percentages of particulate ratio values to total sample number binned according to potential nutrient limitation indicate that 39% (C:N) of the data have values suggesting N limitation and that from 88% (N:P) to 95% (C:P) of the data have values which suggest P-limitation. It is difficult to discern whether phytoplankton biomass is truly P-limited as related to the nutrient regime on the WFS or whether detrital contributions, which can potentially be large on this shallow shelf, are skewing the N:P and C:P ratios towards higher values. Errors which could potentially be related to the different methodologies of determining C, N and P concentrations must also be considered when interpreting the particulate nutrient ratios. The data were also analyzed as subsets to determine near-shore to offshore, latitudinal, seasonal, inter-annual and K. brevis bloom versus non-bloom trends. The near-shore to offshore transect indicates decreasing concentrations of particulate C, N, P concentrations and increasing C:N, N:P, C:P ratios with increasing distance offshore. Particulate nutrient concentrations and particulate ratio values are very similar between the Tampa Bay, Sarasota and Fort Meyers transects indicating that these latitudes are not spatially distinct with regards to these variables. There does not appear to be any relationship between the particulate C, N, P concentrations or C:N, N:P, C:P ratios and rainfall as indicated by Spearman Ranking Correlation coefficients. However, there does appear to be monthly trends across the shelf where peak particulate nutrient concentrations and particulate ratio values occur during the spring, summer and fall. The average particulate nutrient concentrations and ratios differ for each year as well as each K. brevis bloom which occurred during the study period. In summary, the particulate C, N, P concentrations and particulate nutrient ratios vary both spatially and temporally on the WFS and are potentially related to the flexibility of phytoplankton uptake kinetics in response to the varying nutrient regimes of the WFS.

Social insect colonies are complex systems with emergent properties that arise from the cooperation and interaction amongst individuals within colonies. By dividing reproduction and physical labor amongst them, individuals contribute to the growth and ecological success of their colonies, a success that is greater than individuals could achieve on their own. A key characteristic of social insects is a division of labor amongst workers that is determined primarily either by age, morphology, or dominance. Social insects are considered one of the most ecologically successful groups of organisms on earth. Colony life cycles include: 1) growth, in which workers are produced, 2) reproduction, in which queens and males with reproductive capabilities are produced, and 3) senescence. In life history theory, phenotypic plasticity (i.e. a change in phenotype in response to an environmental change), allows organisms to adjust and optimize fitness in response the change in environments. Central to life history theory is the idea that traits have costs and benefits. Using an energetics framework that considers the costs and benefits of traits contributes to our understanding as to why organisms exhibit the sets of traits that they have within their ecological environments. Using the annual bumble bee Bombus impatiens, my dissertation investigates the effects of resource availability on worker production and on the relative allocation of energy towards growth and reproduction within colonies. Bumble bees have a morphological division of labor and concomitantly, they show large intra-colony size variation amongst workers. Because body size is an important life history trait, I also examined the costs and benefits of producing various sized workers. Lastly, I examined the association among worker body size, metabolic rate (a measure of maintenance costs), and lifespan.

Šiame darbe analizuojamas „tuščios laikmenos“ mokestis, jo įgyvendinimas Lietuvoje, bandoma numatyti galimus jo raidos variantus ateityje. Šį darbą suskirstėme į tris dalis: pirmojoje nagrinėjome „tuščios laikmenos“ mokesčio pagrindą – atgaminimo asmeniniais tikslais apribojimą, antrojoje – įvertinome esamą mokesčio surinkimo ir paskirstymo sistemą Lietuvoje, trečiojoje įžvelgėme galimas „tuščios laikmenos“ mokesčio vystymosi perspektyvas. Nagrinėdami asmeninio atgaminimo apribojimą didelį dėmesį skyrėme bendriesiems klausimams (atgaminimo sąvokai, autorių teisių apribojimo sampratai, trijų pakopų testui), tačiau atskleidėme ir konkretaus apribojimo turinį (išnagrinėjome jo apibrėžimus pateikiamus įvairiuose teisės aktuose, aptarėme atgaminimo šaltinio teisėtumo problematiką, apribojimo santykį su vartotojų sudaromomis licencinėmis sutartimis). Vertindami „tuščios laikmenos“ mokesčio įgyvendinimo praktiką Lietuvoje tyrėme kiek mokėtojai ir gavėjai atitinka asmeninio atgaminimo išimties keliamus reikalavimus, kaip mokesčio paskirstymas yra susiejamas su asmeninio atgaminimo išimtimi, nagrinėjome mokesčio tarifo ir apmokestinamų objektų sąrašo pagrįstumą. Įvertinę esamą padėti bandėme įžvelgti galimus jos vystymosi variantus, aptarėme jų tikimybę. / The paper analyzes „blank media“ levy, its practice in Lithuania, looks through possible future development. This work consists of three parts: in the first part we examined the ground of the „blank media“ levy – private copy exception, in the second part we evaluated the system of collection and distribution which is functioning in Lithuania, in the third part of this work we perceived possible future development of „blank media“ levy. Analyzing private copying exception we payed attention on common questions (such as conception of reproduction, limitations of copyright and three step test), but also desclosed the contents of the exact limitation (we have analyzed the conception of private copying exception in various legal acts, discussed problems related to requirements of legality of reproduction source, the relation of consumer licence agreements and limitation). We have evaluated „blank media“ levy realization practice in Lithuania, this was done by studing how payers and recievers of „blank media“ levy coresponds with requirements set by private copy exception, how distribution of levy is connected with limitation, we have searched for the grounds of object and rate of levy. After evaluating the practice of private copying levy, we tryed to percieve future development models of „blank media“ levy and the probability of each of it.

Understanding the functional relationship between characters and components of fitness is a central goal of evolutionary biology. The studies in this thesis examined the ecological causes and evolutionary consequences underlying differences in fitness among individuals of Lobelia cardinalis. Flowering plants experience selection from many sources, which may enhance or oppose selection by pollinators. In the second chapter of this thesis, the role of pollinators and herbivores in shaping selection on floral characters was investigated. Floral traits experienced pollinator-mediated selection and weak selection by weevil larvae and slugs. Because pollinators also forage according to local density of flowers, in the fourth chapter I explored how local density of individual plants and flowers influences fitness of individual plants. Plants at dense sites produced more seeds, consistent with pollinator preference for denser patches. Individual female-phase flowers produced more seeds as the density of surrounding male-phase flowers increased and female-phase flowers decreased. This study highlights how plant phenotype and local density influence pollination and subsequent plant fitness. In L. cardinalis rosette formation (a life-history character) partly shapes the distribution of plants, and may influence plant survival and fitness. In the fifth chapter, I explored how variation in allocation to clonal reproduction among plants (ramets) and genets influenced survival and fitness. Plants that produced more and larger rosettes realized higher survival independent of the phenotype of the parental. Plants that produced one rosette in 2009 produced more seeds in 2010 than plants that produced more than one rosette. This pattern was reversed in the following time period; plants that produced more rosettes in 2010 produced more seeds in 2011. The relative importance of pollinators versus other selective agents in shaping floral traits, as well as the intensity of competition among individual plants and flowers likely depend on the extent to which reproduction is pollen limited. In the third chapter, I explored how pollen limitation affected selection on floral traits via female fitness and found a weak relationship. Although this seems to contradict intuition, several reasons may limit the influence of pollen limitation on selection.

No description available.

<p>Within the context of South Africa&lsquo / s diverging religious, cultural and social backgrounds, new questions on the nature of a multicultural society are raised from the perspective of human rights.&nbsp / The universality and indivisibility of human rights are challenged by this diversity and consequently implies that standards, concepts and structures for implementation have to be reconsidered.&nbsp / International and national standards are being (re)interpreted and attention is not only focused on the contents of the norms but on the limitations imposed thereupon. The debate on whether limits should be set in permitting or accommodating cultural or religious pluralism is becoming extremely relevant. The manner in which these questions are responded to&nbsp / is even more prominent in the light of our history of apartheid which has disregarded respect for religious and cultural diversity. In the scope of this research emphasis will be placed on the&nbsp / right to freedom of religion and in particular the limitation of the right to religion in an attempt to balance conflicting rights and accommodates religious diversity. The right to freedom of religion&nbsp / albeit constitutionally entrenched is subject to reasonable and justifiable limitations. However, no clear guidelines have been formulated on the criteria for limiting the right to freedom of&nbsp / religion. The main aim of this research is to find guiding criteria to facilitate the imposition of limitations on the right to freedom of religion. The limitations of the right to freedom of religion are&nbsp / interrelated with the following research questions: Firstly, the definition afforded to the right to freedom of religion in accordance with national and international standards / secondly, the relationship between culture and religion and any interconnection that exists between these rights. This is followed by the influence of the particular value framework or normative commitments&nbsp / f the judiciary on the interpretation of the right to religion, as well as the relationship between the state and religion. The above issues will be researched both on a national and&nbsp / an international level. The aim is to conduct research that will build on an appreciation of the guidelines that should be employed in ensuring the protection of the right to freedom of religion. To this end comparisons will be drawn with other legal&nbsp / systems, which on the one hand acknowledge the protection of the right to freedom of religion and on the other hand have to find ways in which the right can be balanced in the event of conflict. It is envisaged that the research of the criteria imposed on the limitation of the right to religion both on a national and an international level will assist in suggesting criteria that will influence&nbsp / scholarly debate on the topic. In addition that this debate will allow for the formulation of a transformative approach within the South African context that sanctions the celebration of diversity in all&nbsp / its aspects and in particular the right to freedom of religion.<br /> &nbsp / </p>