Previous studies suggest that global warming threatens populations of Arctic char (Salvelinus alpinus L.) and that interspecific competition from brown trout (Salmo trutta L.) can have negative effects when the species occur in sympatry. The aim of this study was to investigate if populations of Arctic char have declined in the last decades in lakes where they in the past have coexisted with brown trout. I examined this by revisiting five lakes previously sampled in the mountain region of Västerbotten (Sweden) during the 1960´s. This study repeated earlier sampling methods and examined the population size, biomasses and individual size and weight of all fish. Results showed increased abundances of brown trout and a trend towards declining Arctic char populations in the five lakes. Both Arctic char and brown trout currently had higher mean lengths than previous sampling years. This study also examined the diet and growth rate of both species. The diet analysis showed that the species to some extent overlapped in diet, while they also showed clear differences, where Arctic charr e.g. consumed more pelagic zooplankton. The growth rate was higher for Arctic char and differed between lakes. The shift towards more brown trout dominated lakes could depend on both that the two species are differently affected by a warmer climate, and that fishing habits have changed since the 1960´s. A warmer climate likely changed the species interaction in favor of trout and could lead to more competition and predation on Arctic char.

Tato diplomová práce se zabývá zhodnocením inženýrskogeologických poměrů mostu na stavbě č. 519 silničního okruhu kolem Prahy včetně vyšetření stability skalních svahů v místě předpokládané výstavby. Jedná se o přemostění hlubokého erozního údolí Vltavy, na jehož svazích vystupují na povrch horniny svrchnoproterozoického stáří. Na lokalitě byly zhodnoceny pomocí rešerše archivních podkladů, vlastní rekognoskace a laboratorních zkoušek, geologické, hydrogeologické a inženýrskogeologické poměry, které jsou přehledně uvedeny v inženýrskogeologické mapě v měřítku 1:2000 a řezu 1:500. Jako podklad pro vyhodnocení stability skalních svahů sloužila podrobná dokumentace skalních výchozů. Samotné vyšetření stability proběhlo pomocí klasifikace Slope Mass Ratting a Marklandova testu pro stereografickou projekci. Na výstupech práce je souhrnně popsán horninový masiv včetně mapy stability skalních svahů v měřítku 1:500 a popsány základové poměry uvažovaného mostu.

The purpose of this thesis is to investigate day-of-the-week effects for stock index returns. The investigations include analysis of means and variances as well as return-distribution properties such as skewness and tail behavior. Moreover, the existences of conditional day-of-the-week effects, depending on the outcome of returns from the previous week, are analyzed. Particular emphasis is put on determining useful testing procedures for differences in variance in return data from different weekdays. Two time series models, AR and GARCH(1,1), are used to find out if any weekday's mean return is different from other days. The investigations are repeated for two-day re- turns and for returns of diversified portfolios made up of several stock index returns.

De som arbetar där brunbjörnen (Ursus arctos L.) lever riskerar att påverkas genom olycksfall och ohälsa, vilket kan leda till ett arbetsmiljöproblem. Björnpopulationen har efter upp- och nedgångar ökat senaste årtiondena vilket har ökat incidenterna. Syftet med studien var att kartlägga hur anställda som arbetar ensam till fots i fält inom skogsnäringen påverkas av björnens närvaro i skogen och att utreda vad som skulle kunna göra skogen till en säkrare arbetsplats genom att motverka ohälsa och olycksfall kopplat till björnens närvaro. En litteraturstudie och en enkätstudie gjordes för att uppfylla syftet. Resultatet av enkätstudien blev tvetydigt eftersom respondenterna var positivt inställda till björn trots att majoriteten kände sig illa till mods på grund av den. En kollega ansågs vara en trygghet trots att väldigt få var emot ensamarbete. Av respondenterna hade majoriteten varit med om minst ett björnmöte. Som slutsats; utbilda, förekom och försvara.

The carbon-isotope and palynological record through 580 m thick almost continuous brown coal in southeast Australia's Gippsland Basin is a relatively comprehensive southern hemisphere Middle Eocene to Middle Miocene record for terrestrial change. The carbon isotope δ13Ccoal values of these coals range from - 27.7‰ to - 23.2. This isotopic variability follows gymnosperm/angiosperm fluctuations, where higher ratios coincide with heavier δ13C values. There is also long-term variability in carbon isotopes through time. From the Eocene greenhouse world of high gymnosperm-heavier δ13Ccoal values, there is a progressive shift to lighter δ13Ccoal values that follows the earliest (Oi1?) glacial events around 33 Ma (Early Oligocene). The overlying Oligocene-Early Miocene brown coals have lower gymnosperm abundance, associated with increased %Nothofagus (angiosperm), and lightening of isotopes during Oligocene cooler conditions. The Miocene palynological and carbon-isotope record supports a continuation to the Oligocene trends until around the late Early Miocene (circa 19 Ma) when a warming commenced, followed by an even stronger isotope shift around 16 Ma that peaked in the Middle Miocene when higher gymnosperm abundance and heavier isotopes prevailed. The cycle between the two major warm peaks of Middle Eocene and Middle Miocene was circa 30 Ma long. This change corresponds to a fall in inferred pCO2 levels for the same period. The Gippsland data suggest a link between gymnosperm abundance, long-term plant δ13C composition, climatic change, and atmospheric pCO2. Climatic deterioration in the Late Miocene terminated peat accumulation in the Gippsland Basin and no further significant coals formed in southeast Australia. The poor correspondence between this terrestrial isotope data and the marine isotope record is explained by the dominant control on δ13C by the gymnosperm/angiosperm abundance, although in turn this poor correspondence may reflect palaeoclimate control. From the brown coal seam dating, the coal appears to have accumulated during a considerable part of the allocated 30 Ma Cenozoic time period. These brown coal carbon isotope and palynological data appear to record a more gradual atmospheric carbon isotope change compared to the marine record.

Egg stocking in rivers and streams is a common measure to support and re-introduce salmonid populations. To ensure the success of egg stocking programs, knowledge of the early life stages of juveniles including dispersal ability and habitat preferences of fry is a prerequisite. This study was conducted to investigate downstream dispersal patterns and habitat use of young of the year brown trout in a mid-sized, channelized, boreal river in Sweden. Eyed trout eggs were stocked in February of 2021. During August of the same year, 2-3 months after emergence, trout were sampled by electrofishing within 1 km downstream of the stocking sites and each individual point of capture was recorded by GPS. In addition, data on riverbank slope, shoreline irregularity, stream bed substrate, water velocity and water depth were collected for each of the sampling sections. The results showed that trout fry were distributed throughout the 1 km long sampled sections and that the density of fry did not increase towards the stocking points. The observed variation in the distribution of trout fry was best explained by the riverbank slope. Approximately twice as high fry densities were found in reaches with gentle compared to medium and steep bank slopes. The differences are suggested to be an effect of 1) stream marginal water velocity differences during high flows affecting fry occupancy, and 2) that gentle slopes were often accompanied by shallow water, preferred by fry. These findings may provide helpful knowledge for fisheries managers to optimize the outcome of egg stocking and river restoration activities regarding fry recruitment. / Romutsättning i vattendrag är en vanlig åtgärd för att stärka och återetablera populationer av laxartade fiskar. För att lyckas med romutsättningar krävs kunskap om ynglens spridningsförmåga och habitatpreferenser. Denna studie genomfördes för att undersöka spridningsmönster och habitatval av ensomrig öring i en medelstor kanaliserad älv i Sverige. Ögonpunktad rom sattes ut i februari 2021. Under augusti samma år, 2-3 månader efter att ynglen lämnat lekgruset elfiskades 1 km långa sträckor direkt nedströms utsättningsplatserna. De fångade individernas position registrerades med GPS. Data över strandkantens lutning, strandzonens flikighet, bottensubstrat, vattenhastighet och djup samlades in för varje elfiskesträcka. Resultatet visade att öringyngel spridit sig över hela de 1 km långa elfiskesträckorna, och att tätheterna av yngel inte ökade med minskat avstånd till utsättningspunkterna. Den observerade variationen i fördelningen av öringyngel förklarades bäst av strandkantens lutning. Ungefär dubbelt så hög täthet av yngel förekom i sträckor med flack jämfört med medel och brant lutning. Skillnaderna föreslås vara en effekt av 1) skillnader i vattenhastighet under höga vattenflöden som påverkar ynglens möjligheter till att bibehålla sin position i habitatet, och 2) att flack lutning av strandkanten ofta åtföljdes av grunt vatten vilket föredras av yngel. Dessa upptäckter kan bidra med värdefull kunskap för att optimera romutsättningar och restaureringar i avseende på rekrytering av årsyngel.

Estimates of the brown trout (Salmo trutta) population were made in two areas of the Blacksmith Fork River, Cache County, Utah, from June 1972 to June 1973. Additional data were obtained on movement, growth, mortality, biomass, production, and yield. Population density was highly variable in the area where habitat alterations had occurred, but was relatively uniform where the habitat was undisturbed. The brown trout exhibited little movement except during spawning season. Instantaneous growth and mortality rates are provided for each age group. Mean annual biomass in the two areas was 12.0 and 10.2 grams per square meter and production was estimated at 9.2 and 7.7 grams per square meter per y ear in the two study areas. Gametes comprised approximately 5 percent of the annual production and angler harvest removed 39 percent of production.

The field of historic preservation has undergone· extreme changes in recent years. Only in the last few years have schools, businesses, and the public been interested in preserving historic sites. Prior to this involvement, historic preservation was accomplished by a few individuals and patriotic groups. Since the field is relatively new, little has been researched and written regarding the early efforts of preservation. One man who emerged as a leader in the preservation movement in Oregon, for over thirty years, was Burt Brown Barker. This thesis, through research of the files associated with five different preservation projects, examines the role Barker played. In each case, an exhaustive search was made of all the files and scrapbooks housed at each institution. In addition, using contemporary newspaper-accounts, Barker's unpublished autobiography, and several books relating to historic preservation, a careful examination of Barker's role can be made. An analysis of the research shows that the role Barker played in historic preservation was a significant one. His contributions to the preservation of historic pioneer sites in Oregon remains a lasting memorial to the determination of this man. Though his name is relatively unknown, this thesis shows that he deserves to be recognized and remembered for his efforts.

No description available.

Les exoplanètes peuvent être détectées par plusieurs méthodes. De celles-ci, la méthode des Vitesses Radiales (RV) est dite indirecte, car l'on observe le spectre lumineux de l'étoile hôte et non la planète directement. Or, plusieurs facteurs influencent les variations lumineuses d'une étoile hormis la présence d'un compagnon. La photosphère des étoiles comprend des régions plus sombres appelées taches stellaires causées par de forts champs magnétiques qui restreignent le déplacement de l'énergie vers la surface. Lorsque l'étoile tourne, elles se déplacent produisant ainsi des variations dans le spectre de l'étoile similaires à celles induites par les corps l'orbitant. C'est pourquoi la modélisation de l'activité stellaire est essentielle pour la recherche d'exoplanètes. Il existe maints indicateurs d'activité dont la photométrie et les bissectrices et le Full Width at Half Maximum (FWHM) obtenus du profil moyen des raies spectrales. Ils peuvent être modélisés à l'aide d'outils mathématiques comme les Processus Gaussiens (GP). L'étoile GL229 A est une naine rouge située à 5.75 parsecs autour de laquelle orbite la première naine brune, GL229 B, découverte par imagerie directe en 1995. À mi-chemin entre planètes géantes et étoiles naines, ces objets sous-stellaires n'ont pas acquis la masse nécessaire pour déclencher la fusion nucléaire de l'hydrogène lors de leur formation. Le système GL229 fut aussi observé par différents télescopes dotés d'instruments permettant d'obtenir des mesures de RV. Ceci mena, en 2014 et 2020, à la détection de deux exoplanètes, GL229 A b et A c aux masses minimales de 32 et 7 masses terrestres. Ce mémoire présente une réanalyse des RV obtenues avec HARPS, un spectrographe échelle. En modélisant le FWHM avec un GP, il peut être démontré que les signaux précédemment identifiés comme d'origine planétaire correspondent en fait à des signaux d'activité stellaire. / Several methods can detect exoplanets. Of these, the Radial Velocity (RV) method is said to be indirect because the light spectrum of the host star is observed and not the planet directly. However, several factors influence a star's luminous variations apart from a companion's presence. The photosphere of stars contains darker regions called star spots caused by strong magnetic fields that restrict the movement of energy to the surface. When the star rotates, these spots move, producing variations in the star's spectrum similar to those induced by the bodies orbiting it. Hence, stellar modelling activity is essential when searching for exoplanets. Many activity indicators, including photometry and bisectors and Full Width at Half Maximum (FWHM) obtained from the average spectral line profiles, can be modelled using tools such as Gaussian Processes (GP). GL229 A is a red dwarf located at 5.75 parsecs around which orbits a brown dwarf, GL229 B, firstly discovered through direct imaging in 1995. Halfway between giant planets and dwarf stars, these substellar objects did not acquire the mass necessary to trigger nuclear hydrogen fusion during their formation. The GL229 system was also observed by various telescopes equipped with instruments making it possible to obtain RV measurements. This led, in 2014 and 2020, to the detection of two exoplanets, GL229 A b and A c, with minimum masses of 32 and 7 Earth masses. This thesis presents a re-analysis of the RVs obtained from HARPS spectra, an échelle spectrograph, for the Gliese 229 system. By modelling the FWHM with a GP, we show that previously identified planetary signals are not real and result from stellar activity.