I investigate aspects of fleet dynamics in a mobile gear, groundfish fishery, on the Scotian Shelf; an area subject to a seasonal area closure. Firstly, the direct impacts of the closure on the redistribution of fishing effort and the resultant catch rates of those “fishing the line” (FTL) were examined. Effort was found to concentrate within 30km of the closure boundary. Two areas of potential FTL strategy were identified, which produced variable catch rate trends. East of the closure, areas of highest catch rate corresponded to areas of greatest effort, while to the west, catch rate was often equalized throughout the region, analogous to the ideal free distribution (IFD). Secondly, two effort distributional models were compared: an IFD-based isodar model and a discrete choice model. The isodar was determined to be the preferred model because of both its consistently superior predictive performance and its greater simplicity.

The purpose of this study was to investigate if there is a seasonal difference in metal concentrations in marine gastropods. Metals that were studied were chromium, copper, nickel and zinc. Gastropods were collected at one contaminated site and one reference site. For the contaminated site Rönnskärsverken, Skellefteå, Sweden, was chosen because of its long history as location for a smelter. Kylören, Umeå, Sweden, was chosen as reference site.  The gastropods were collected on two occasions at each site, the first time in the beginning of June and the second time in the end of August. The gastropods were then removed from their shells and the tissue was analyzed spectrometrically for metal content after acid-digestion. The results from the analysis showed unsurprisingly that metal contamination was higher at the contaminated site than at the reference site. More interestingly, it was also found that there are seasonal differences in almost every metal included in the study. Nickel and chromium concentrations were significantly increased (P<0, 05) in the end of the summer and the zinc concentration had the highest value in June in Rönnskärsverken but the highest value in August for the reference site. As only exception, copper concentration did not show any seasonal variation in snail tissue. In conclusion this study shows that there are seasonal differences in metal concentrations in marine gastropods but the differences are not consistent and differs from metal to metal if the concentration is increased in the beginning or the end of summer.

Žiniasklaida yra vienas iš pagrindinių visuomenės informacijos šaltinių. Šiandien, kai plinta nauji ir nuolat mutuoja seni ligų virusai, kyla rizika žmogaus sveikatai, tikėtina, jog masinės informa-vimo priemonės bus pirminis informacijos šaltinis. Kaip rodo atlikti tyrimai, žiniasklaida formuoja rizikos suvokimą visuomenėje. Atrinkdama, kokie pranešimai pateks į naujienų skiltį bei suteikdama vieniems įvykiams didesnę reikšmę negu kitiems, žiniasklaida tarsi pasufleruoja visuomenei ne tik, apie ką mąstyti, bet ir kaip mąstyti. Šio darbo tikslas - išanalizuoti Lietuvos internetiniuose portaluose konstruojamą sezoninių virusų diskursą. Darbe analizuojama diskurso sociologinė samprata, remiantis socialinio konstrukcionizmo ir darbotvarkės formavimo teorijomis, nagrinėjama rizikos komunikacijos samprata, rizikos visuomenei būdingi bruožai, riziką stiprinantys/silpninantys veiksniai, ekspertų vaidmuo rizikos valdyme. Taikant diskurso analizės strategiją, naudojant kiekybinę ir kokybinę turinio analizę, bandoma atskleisti, kaip remiantis naujienų atrankos kriterijais, parenkant retoriką bei vizualinius elementus žiniasklaidos pra-nešimuose kuriamas sezoninių virusų diskurso turinys. Kokią informaciją žiniasklaida skleidė sezoninių virusų sergamumo laikotarpiu bei kokią visuomenės nuomonę formavo apie sezoninius virusus. Tyrimui pasirinkti Lietuvoje dažniausiai lankomi portalai „delfi.lt“, „lrytas.lt“, „balsas.lt“, alfa.lt“ ir „15min.lt“. Tiriamasis laikotarpis: 2012 m. gruodžio -... [toliau žr. visą tekstą] / The media is one of the main public sources of information. Today, as new viruses of diseases are spreading and the old ones mutate constantly, there is a risk to human health, it is likely that the mass media will be a primary source of information. As the studies show, the media shapes public’s perception of risk. Selecting which messages will go to the news section and giving more important role to ones than the others, as if the media prompts the public not only what to think about but how to think. The aim of this work was to analyze the discourse of constructed seasonal viruses in the Lithu-anian internet portals. The thesis analyzes the discourse of sociological concept based on social constructionism and agenda-setting theories, examined the concept of risk communication, features of risk characteristic to the public, factors strengthening / weakening the risk, the role of experts in risk management. Applying the strategy of discourse analysis, using quantitative and qualitative content analysis, it is attempted to uncover how on basis of news selection criteria, selecting rhetoric and visual elements of the media messages, seasonal viruses discourse content is being created, as well what information the media spread during the period of seasonal virus morbidity, and what public opinion was formed on seasonal viruses. For the survey the most frequently attended Lithuanian portals, such as “Delfi.lt”, “Lithuanian Morning”, "The Voice," Alpha "and "15 minutes”... [to full text]

This document presents the energy analysis and simulation of central solar heating plants with seasonal storage (CSHPSS) designed for covering a part of residential heat demand required for SpaceHeating (SH) and Domestic Hot Water (DHW) oriented to reduce the consumption of fossil fuels.The main objectives of this thesis are to simulate and analyse in POLYSUN software a defined systemof CHSPSS already built in TRNSYS, in order to compare the results of both programs and to analyse and simulate these systems in different cities of Spain. In carrying out the objectives, some limitations have been found. Ones of these are the limitations of POLYSUN program, which have forced to reduce the number of housings. The document starts with a revision of the state of art, in which it is shown the number of plants in Europe and specially, in Sweden and Spain observing the differences between them, for example, Spain has not any CSHPSS plant and Sweden was the first country of building one. In addition, in the theory section, it has been studied the main elements of these plants, such as different types of solar collectors and seasonal storages, and different simulation programs commercially available for the simulation and analysis of this type of plants. According to this, POLYSUN program is more intuitiveand user-friendly in some extent than TRNSYS, but its applications are more specific and more appropriate for small district heating systems. Steps followed for obtaining the analysed system and main characteristics of it have been explained.These steps have been used to analyse the results of POLYSUN and to compare results betweenTRNSYS and POLYSUN. According to the obtained results, it can be remarked that the results obtained from POLYSUN are coherent, with the exception of Space Heating demand, which is calculated by the program and has a very important difference between the calculated value and the Space Heating demand introduced by the user. When comparing with TRNSYS, it has been observed that POLYSUN‘s boilers have a high thermal losses and low efficiency and POLYSUN’s pumps have high energy consumption and thermal losses.

The Common River Frog Amietia quecketti is a well-known and widely distributed species in southern Africa. Despite the fact that it is a common species and quite prevalent in urban areas little is known about its behaviour. The North-West University Botanical Gardens was selected as study area as it supports a healthy population of Common River Frogs at a series of 18 water bodies. Each pond in the Garden was assigned a reference number and the surface area, depth and vegetation were noted. Frogs were located with the aid of strong flashlights. Specimens were caught by hand and transferred to clear plastic bags. Frogs were sexed and their mass and their snout-vent length (SVL) were determined. Frogs were subsequently individually marked by means of injecting a micro-transponder (pit-tag) subcutaneously. Field observations were conducted over two consecutive evenings every two weeks for a period of one year. On the first night all sites were visited and all frogs were scanned and their position, orientation and activity were noted. During the second night focus was on Pond 6 as it sustained the biggest population. Observation started at 19:15 and continued until 02:30. All frogs in and around the pond were scanned and detailed notes were taken, focusing on their orientation, behaviour, calling activity and distance to the nearest other frog. Results showed that limited movement between ponds in the Garden does occur. A number of individuals were recorded regularly. Some males had preferred call sites, and clear circadian and seasonal patterns with regards to males and females exist. The complex call structure consist of a chuck and a whine and then a combination of the two. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2013

The Common River Frog Amietia quecketti is a well-known and widely distributed species in southern Africa. Despite the fact that it is a common species and quite prevalent in urban areas little is known about its behaviour. The North-West University Botanical Gardens was selected as study area as it supports a healthy population of Common River Frogs at a series of 18 water bodies. Each pond in the Garden was assigned a reference number and the surface area, depth and vegetation were noted. Frogs were located with the aid of strong flashlights. Specimens were caught by hand and transferred to clear plastic bags. Frogs were sexed and their mass and their snout-vent length (SVL) were determined. Frogs were subsequently individually marked by means of injecting a micro-transponder (pit-tag) subcutaneously. Field observations were conducted over two consecutive evenings every two weeks for a period of one year. On the first night all sites were visited and all frogs were scanned and their position, orientation and activity were noted. During the second night focus was on Pond 6 as it sustained the biggest population. Observation started at 19:15 and continued until 02:30. All frogs in and around the pond were scanned and detailed notes were taken, focusing on their orientation, behaviour, calling activity and distance to the nearest other frog. Results showed that limited movement between ponds in the Garden does occur. A number of individuals were recorded regularly. Some males had preferred call sites, and clear circadian and seasonal patterns with regards to males and females exist. The complex call structure consist of a chuck and a whine and then a combination of the two. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2013

In 1955 and 1966 Canada opened its doors to a limited number of Caribbean domestic workers and seasonal agricultural workers. Canadian government officials remarked that the programmes were part of Ottawa’s aid package to the Caribbean and that they would enhance trading relationships between Canada and the Caribbean, a view which had been echoed by other writers on the topic. This thesis argues that both programmes were instituted after Canada had exhausted all attempts to recruit adequate European labourers. The thesis also argues that both programmes were deliberately designed and executed to ensure that Canada got maximum benefits at low cost. Canada also attached unprecedented conditions to both schemes in an effort to significantly reduce the number of workers recruited. The thesis provides a thorough examination of the proposals by Caribbean governments, together with interest groups from Canada, to persuade Canada to establish these migrant programmes and the excuses and refusals by Canada to those proposals. The thesis documents the increasing recruitment of Mexican agricultural workers at the expense of Caribbean workers which further dispels the view that the migrant programmes were part of an aid package to the Caribbean. The thesis notes that unlike the domestic programme the agricultural programme was not a route towards landed immigrant status.

The structure of phytoplankton communities was examined seasonally across five rivers with a focus on small cells and their relative importance. Picophytoplankton (0.2-2 μm), previously considered insignificant in rivers, reached densities as high as those observed in lakes and oceans (~ 10e4-10e5 cells/mL). Their relative importance was not a function of trophic state with the highest contribution to algal biomass found in the most eutrophic river. Body size distributions were analyzed from both chlorophyll-a size fractions and taxonomic enumerations; no significant effect of river or season was detected, suggesting that phytoplankton size distribution is not a useful metric of change in rivers. Unlike lake ecosystems, the rivers were uniformly dominated by small cells (< 20 μm). Taxonomic analyses of the seasonal succession did not reveal a common periodicity of particular divisions (e.g. diatoms). However, strong dominance was more typical of eutrophic rivers even though taxa richness was similar.

I investigate aspects of fleet dynamics in a mobile gear, groundfish fishery, on the Scotian Shelf; an area subject to a seasonal area closure. Firstly, the direct impacts of the closure on the redistribution of fishing effort and the resultant catch rates of those “fishing the line” (FTL) were examined. Effort was found to concentrate within 30km of the closure boundary. Two areas of potential FTL strategy were identified, which produced variable catch rate trends. East of the closure, areas of highest catch rate corresponded to areas of greatest effort, while to the west, catch rate was often equalized throughout the region, analogous to the ideal free distribution (IFD). Secondly, two effort distributional models were compared: an IFD-based isodar model and a discrete choice model. The isodar was determined to be the preferred model because of both its consistently superior predictive performance and its greater simplicity.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniversitet, 2005. / Härtill 4 uppsatser.