I studied the effects of temperature, pH, competition and predation on Eurasian perch (Perca fluviatilis) in 30 lakes in Norway during 1981-2001. The study lakes were situated in two different areas in southern Norway; four lakes in Aust-Agder county in southernmost Norway were explored during 1981-1984 and 26 lakes in Hedmark county in south-eastern Norway were investigated during 1992-2001. The study lakes varied considerably in pH, temperature, fish species composition, and perch abundance and size composition. In addition to field surveys, behavioural studies of perch were conducted at Karlstad University in 2006-2007. The field studies revealed that temperature affected recruitment of perch as strong year-classes of perch generally occurred in summers with high temperatures. Temperature also affected perch behaviour as indicated by the low gillnet catches (CPUE) of perch atlow temperature. This effect on CPUE was also supported by results from the aquaria experiments, where swimming and feeding activity of perch was low at low temperature. In a study of four lakes, growth was positively related to temperature in the lake with an allopatric perch population, but not in three lakes where perch occurred sympatrically with roach. pH also affected recruitment. In the four lakes in Aust-Agder, one strong year-class of perch occurred in all lakes in a year with especially high pH in spring and early summer. Adult mortality was also affected by pH, as old perch were less abundant in lakes with late spring pH=5.5-5.8 than in lakes with pH<5.5 and pH>5.8. The size and growth of adult perch were negatively affected by low pH, whereas abundance of large, potentially predatory perch was positively related to pH. The field studies indicated that roach influence perch populations. When coexisting with roach, perch were mainly littoral. In lakes where roach dominated (by number), there was no growth – temperature correlation, but there was such a correlation in lakes without roach. In lakes with sympatric roach, age-specific weight of perch and the growth of 2+ perch were negatively related to the proportion of roach in the gillnet catches. In the aquaria experiments, swimming and feeding activity of perch were lower than that of roach at all temperatures tested, and the difference was most pronounced at 4 and 8 °C. The aquaria experiments indicated that perch had a lower feeding efficiency and that they generally occupied positions closer to the bottom than roach.

Thesis (MEng) -- Stellenbosch University, 2014. / ENGLISH ABSTRACT: Beamforming is a technique used to combine signals from an array of antennas to effectively synthesize a single aperture and beam. In the Radio Astronomy community the technique is used to obtain a desirable beam pattern as well as to electronically point the beam of an array. Next generation radio telescopes such as the Square Kilometre Array (SKA) surpass current technology and will extensively make use of beamforming techniques. Various factors determine the output of a beamformer; however, given an array with a fixed configuration only the weights applied to the incoming signals affect the synthesized aperture and beam. Furthermore, the incoming data must be processed in real-time, at a rate equal to the input-output rate of the processor. Both the weighting function and the real-time implementation of beamforming, are the primary subjects of this thesis. In this thesis various deterministic weighting functions are investigated. The algorithms are implemented in a matlab program, serving as a simulation tool for investigating the techniques. The program is verified by comparing the expected theoretical outcomes to the simulated output. For the program the following functionalities are included: a steering technique, spectral weighting, Dolph-Chebychev, and the Least Square Error algorithm. Applications of these techniques is investigated and their prominence in the Radio Astronomy community is established. For the real-time beamformer implementation, the UniBoard platform configured with beamformer firmware, is investigated. This is important as the UniBoard is an excellent example of a beamformer implementation within the Radio Astronomy community. The architecture is used to emulate a linear array by implementing a python control script, where the output corresponded accurately with the expected theoretical values. The thesis also constitutes the design and implementation of a digital frequency domain beamformer on the ROACH board. This processing board is employed by the Karoo Array Telescope (KAT-7) in South Africa. This work is therefore important as it demonstrates a beamformer implementation on an architecture in use by the Radio Astronomy community. An antenna array is designed and built for the verification of the beamformer design. Results with a good degree of accuracy were obtained and where errors exist they are discussed. / AFRIKKANSE OPSOMMING: Bundelvorming is ’n tegniek waarmee die seine van ’n antenna samestelling gekombineer word om ’n enkele effektiewe stralingsvlak en stralingspatroon te sintiseer. In die Radio Astronomie gemeenskap word die tegniek gebruik om ’n gewenste stralingspatroon te sintiseer sowel as om die rigting van die patroon elektronies te beheer. Die Square Kilometre Array (SKA) is ’n toekomstige radioteleskoop en sal grootliks gebruik maak van bundelvorming tegnieke. Die uitset van bundelvormers word geaffekteer deur verskeie faktore, maar vir ’n gegewe samestelling is dit net die gewigsfunksies wat toegepas word op die inkomende seine wat die gesintiseerde patroon kan beheer. Verder moet die inkomende data verwerk word teen ’n tempo gelykstaande aan die inset-en-uitsetkoers van die verwerker. Die gewigsfunksie so wel as die implementasie van die bundelvormer is albei primêre onderwerpe van die tesis. ’n Verskeindenheid van deterministiese bundelvormingstegnieke sal ondersoek word in hierdie tesis. Die algoritmes is in ’n matlab program geïmplementeer vir simulasie doeleindes. Die program is geverifieër deur die uitset te vergelyk met die verwagte teoretiese waardes. Die program sluit die volgende funksies in: ’n rigting beheer algoritme, spektraalgewigte, Dolph-Chebychev, en die minste vierkantsfout algoritme. Hierdie tegnieke is van belang weens hul toepassing in die Radio Astronomie gemeenskap. Vir die implementasie van ’n bundelvormer is die UniBoard hardeware, geprogrameer in ’n bundelvormings modus, van gebruik gemaak. Hierdie aspek is belangrik omdat die Uni- Board ’n goeie voorbeeld van ’n geïmplementeerde bundelvormer in die Radio Astronomie gemeenskap is. Die UniBoard word gebruik om ’n lineêre samestelling te emuleer deur in python ’n beheer skrip te skryf, waar die uitset van die emuleerder akkuraat ooreenstem met die verwagte waardes. Die tesis behels ook die ontwerp en implementasie van ’n digitale frekwensiegebied bundelvormer op die ROACH platform. Hierdie verwerker word tans gebruik in die Karoo Array Telescope (KAT-7) in Suid-Afrika. Hierdie werk is dus belangrik omdat dit die implementasie van ’n bundelvormer op tegnologie wat huidiglik in die Radio Astronomie gemeenskap gebruik word demonstreer. Daarbenewens is ’n antenna samestelling ontwerp en gebou om die bundelvormer te verifieër. Die resultate is akkuraat tot ’n redelike mate. Waar daar ’n fout onstaan het word dit in die tesis bespreek.

The main objective of the diploma thesis was defined as the consideration of the hypothesis that food intake structure of adult roach changes significantly during the spawning period. The practical experiment was conducted to reach the defined aim. The experiment was performed on the Brno and Hamry Reservoirs in 2008 and 2009. The acquired data were analysed by standard tools used for gut contents analyses (Indirect Method, Frequency of Occurrence, Index of Fullness, Index of Preponderance) related to the Gonadosomatic Index.

Pour développer des biomarqueurs permettant d'estimer l'état de santé des animaux et de prévoir les effets des contaminants sur les niveaux d'organisation biologique supérieurs, le métabolisme énergétique apparaît comme un candidat de choix. En effet, il participe à la mise en place de grandes fonctions comme par exemple la reproduction ou la croissance. L'altération des processus d'allocation énergétique par la contamination peut avoir des conséquences sur le devenir des individus et de leurs populations. L'objectif de ce travail est d'analyser en laboratoire les impacts potentiels de xénobiotiques (cuivre et éthofumésate) sur le métabolisme énergétique d'un cyprinidé, le gardon Rutilus rutilus, à travers l'étude des processus participant à la formation d'énergie cellulaire(ATP). L'effet des xénobiotiques sur l'état de santé général des juvéniles de gardons a d'abord été appréhendé, et peu d'impacts ont pu être observés sur les indices généraux mesurés. L'effet des contaminants sur la formation aérobie et anaérobie de l'énergie (glycolyse, ses substrats et produits) a ensuite été évalué. Si des différences d'effet des deux contaminants ont été observées au niveau moléculaire, ils ont tous deux induit une augmentation du métabolisme anaérobie au niveau biochimique. Enfin, l'impact des contaminants sur les fonctions mitochondriales a été appréhendé.Des atteintes ont été observées au niveau de la chaîne respiratoire et des ultra-structures des mitochondries, impliquant un effet sur l'énergie cellulaire disponible. Ce travail constitue la base du développement de nouveaux marqueurs précoces de troubles physiologiques des organismes utilisables en biosurveillance. / The energy metabolism constitutes an appropriate approach for the development of biomarkers allowing to estimate the health status of animals and to predict the effects of contaminants on higher levels of biological organization. Indeed, it participates in the establishment of key functions such as reproduction or growth. Alterations of energy allocation process by the contamination can affect the fate of individuals and populations. The aim of this study was to determine in laboratory the potentials effects of chemicals (copper and ethofumaste) on energy metabolism of a cyprinid species, the roach Rutilus rutilus, through the study of processes involved in the synthesis of cellular energy (ATP). The effect of chemicals was first performed on general health status of juvenile roach, and few impacts were found on general indexes measured. Secondly, the study of aerobic and anaerobic energy production (glycolysis, substrates and products) was performed. Significant differences were observed at the molecular regulation level, depending on chemicals. However, at the biochemical level, an increase in anaerobic metabolism was observed with both contaminants. Finally, the effects of contaminants on mitochondrial functions were assessed. Mitochondrial alterations were observed either in the respiratory chain and in the ultra-structure of mitochondria;these results involved an effect on the availability of cellular energy. This work constitutes the basis for the development of new early markers of physiological disorders in organisms used in biomonitoring studies.

Vattenkraftens effekter på vandrande fiskarter har varit kända länge och väldigt få har de anpassningar som behövs för att vara funktionella för både upp-och nedströmsvandring för migrerande arter. Numera vet man det även finns ett behov för svagsimmande arter att använda fiskpassager och för att underlätta för dessa så har man testat olika alternativ som ska fungera för flera olika arter, bl.a. att placera substrat i form av sten eller grus i kulvertar. Vilket har visat sig vara effektivt för just svagsimmande arter genom att det sänker energikostnaden att passera och ökar attraktionen till en mer naturlig struktur. För att öka kunskapen om substrat har en effekt även vid nedströmspassage, så utfördes en experimentell studie om hur substrat påverkar nedströmspassage för mört vid avledning vid ingången till en passageöppning i en artificiell strömränna. Mörten märktes med PIT-tags och kameror placerades ut i olika vinklar för att analysera mörtens beteende. Resultatet visade att mörtar utan substrat hade en snabbare passagetid än mörtar med substrat, men även att mörtar utan substrat tog sig till flyktöppningen snabbare än mörtar med substrat. Orsaken till den långsammare passagetiden kan bero på att substratet framkallade turbulens som därmed fördröjde mörten till att undersöka flyktrännan, då inget annat beteende skiljde mellan de olika behandlingarna. Ytterligare analyser hade behövts av mörtens beteende innan flyktöppningen för att se var de blev fördröjde och då kanske få reda på orsaken. Att fortsätta undersöka fiskars beteende är viktigt för att kunna få fram fungerande alternativ på förbättringar för migrerande fiskar, det måste vara funktionellt för fler arter för att kunna gynna både miljön, naturen och vattenkraften. / The effects of hydropower on migratory fish species have been known for a long time, but very few are adapted for both upstream and downstream migration. Nowadays it is known that there is also a need for weak-swimming species to be able to use fish passages and to facilitate these, various alternatives have been tested that are functional for several different species, for instance placing substrate in the form of stone or gravel in culverts. Which has proven to be effective for weak-swimming species, because it lowers the energy cost of passing and increases the attraction to a more natural structure. In order to increase knowledge about substrate and if it also has an effect on downstream passage, an experimental study was carried out on how substrate affects downstream passage for roach through a bypass. The roach were marked with PIT-tags and cameras were placed at different angles to analyze the3roach´s behavior. The results showed that roach without substrate had a quicker passage time than roach with substrate and that roach without substrate reached the bypass faster than roach with substrate. The reason for the slower passage time may be due to the substrate causing turbulence and therefore delayed the roach to examine the bypass, as no other behavior differed between the different treatments. Further analyzes had been needed of the roach behavior before the bypass to be able to see where they were delayed and then perhaps find out what caused it. Continuing to investigate fish behavior is important in order to be able to develop alternatives to improvements for migratory fish, it must be functional for more species in order for the environment, nature and hydropower to benefit from the measure.

Climate change will lead to higher temperatures and longer summers in the future, which will likely influence the growing season of fish living in temperate lakes. The warm summer of 2018 in Sweden matches prognoses for normal summers at the end of the century and can thus be used to investigate the effect of temperature related factors on fish growth. In this study I used back-calculation of the growth of roach (Rutilus rutilus) caught in Lake Tåkern, Sweden, to find differences in growth during 2018’s hot summer versus the period 2012-2017. I compared growth during these years with results from a similar study from Lake Tåkern in 1978. For this comparison I used 1977 as a representative year for the 1970’s. I applied sclerochronology to the scales to determine age and growth. The results show that growth in terms of length increment was faster in 2018 than in 2012 – 2016. The results indicate that 2018 had an effect on the whole roach population, since significant differences were found across age groups. Additional comparisons between 1977 and 2018 showed no significant difference. Differences in roach growth rate between 2012-2018 could be caused by the differences in mean temperature during the roaches growing season, since 2018 was abnormally warm, and the difference between 1997 and 2018 could be attributed to 1977’s fish death. This means that if the pattern of climate change continues, roach growth rates will increase in the future regardless of age group.

The study is to establish whether there is any impact on the social media company that is implementing the deceptive design on the account deletion process. By conducting the qualitative research with Instagram users and analyzing users’ feelings, opinions, and potential actions, the study finds out using the deceptive design on account deletion process on social media has a weak influence on the social media company.

Att härma och hitta inspiration från förebilder har varit vardaglig praxis under jazzhistorien. Genom att appropriera (Säljö, 2014), lägger individer beslag på andra individers kunskap och omvandla det till egen kunskap. Senare i externaliseringen (Bruner, 2002) synliggörs kunskapen i handling. I denna studie har metoderna plankning och transkribering undersökts som verktyg för att utveckla eget solospel på trumspel. Genom att följa den egna läroprocessen undersöktes också hur man pedagogiskt kan använda plankning och transkribering som metod för att bidra till konstnärlig utveckling. Den musikgenre som behandlas i studien är jazz, där trumslagaren Max Roach solospel använts genom valda exempel. I resultatet presenteras en jämförelse av två egna trumsolon där ett spelades in i början och ett i slutet av studien. Läroprocessen i övningsrummet och under instrumentallektioner har dokumenteras med hjälp av loggbok. Resultatet visar att en del fraser har härmats exakt och en del har härmats rytmiskt men med en egen konstnärlig prägel. Vid en egen konstnärlig prägel av en exakt rytm har en antydan till ett mer självständigt solospel påträffats och plankning och transkribering har visat sig fungera som metod för att utveckla solospel, men metoden är tidskrävande.

The sexual segregation, defined as different use of space by sexes is widespread phenomenon in the animal tree of life. As a result of segregation there is a different use of resources such as habitat, prey items or different threat by predation. Nevertheless it is not well studied in fish taxa except in marine environment. The common and widespread freshwater species such as a bream (Abramis brama), a bleak (Alburnus alburnus) and a roach (Rutilus rutilus) so far have not never been studied from the perspective of sexual segregation too. This thesis aims to examine the sexual segregation of these species and to test premises of sexual segregation such as sexual size dimorphism, age composition and differences in food. Afterwards the different space use of sexes in the Římov reservoir was tested. The gillnet sampling was used to collect data. Gillnets were installed to four localities in longitudinal gradient of reservoir in epilimnion where is the highest abundance of fish. Sampling was performed in August from 2009 to 2016. Results of this thesis show that females and males have different life histories and that bleak and roach are significantly bigger and older than males. The size dimorphism in bream was confirmed but not age difference between sexes. Sexes of bream had different diet. Males...

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