Observations on the distribution, daytime migrations and daily food intake rates of Chaoborus flavicans (Meigen) in the Goggausee [Translation from: Carinthia II 165(85), 184-190, 1975]

The Goggausee, in spite of its modest depth (Zmax = 12 metres), shows meromictic properties: autumn and spring circulation extend only to a depth of 8 metres. The water layers below about 10 metres are constantly oxygen-free, the critical zone with at least intermittent oxygen loss lies at a depth of between 6 and 10 metres. A limnological excursion in May 1974 offered an opportunity to investigate the daily vertical migration of the species Chaoborus flavicans with reference to its food supply of zooplankton as well as the chance to carry out some preliminary experiments on its rate of food intake. Among the studied features were the planktonic depth distribution of Chaoborus flavicans and the food intake of Chaoborus larvae under experimental conditions.

Avaliação dos teores de resíduos do pesticida ditiocarbamato no solo de uma cultura de couve (Brassica Oleracea L.) utilizando cloridrato de L-cisteina para preservação das amostras

Os pesticidas etileno-bis-ditiocarbamatos da classe dos ditiocarbamatos estão entre os fungicidas mais empregados em todo o mundo para o controle de pragas. Muitos métodos para determinar ditiocarbamatos são baseados na hidrólise ácida em presença de cloreto estanoso e análise do CS2 gerado por diferentes técnicas. Nesse contexto, constituiram em objetivos do presente trabalho, como primeira etapa, o estudo de condições adequadas à estocagem de amostras de solo, e como segunda etapa, a avaliação das taxas de degradação e de lixiviação do fungicida mancozebe num cambissolo distrófico através do método espectrofotométrico. O sítio de estudo foi uma área delimitada de 36 m2, de uma cultura de couve, localizada em São Lourenço no 3 distrito do município de Nova Friburgo-RJ. As análises foram realizadas no laboratório de tecnologia ambiental (LABTAM/UERJ). Na primeira etapa, duas sub-amostras de solo contaminadas com mancozebe foram submetidas a tratamento com cloridrato de L-cisteina e estocadas às temperaturas ambiente e de -20C, sendo posteriormente analisadas em intervalos de 1, 7, 15 e 35 dias após a aplicação do fungicida. Outras duas sub-amostras não tratadas com cloridrato de L-cisteina foram submetidas às mesmas condições de temperatura e analisadas nos mesmos intervalos de tempo. Na segunda etapa, foi efetuada a aplicação do fungicida MANZATE 800 (Dupont Brasil, 80% mancozebe) na dose recomendada de 3,0 Kg ha-1 e coletadas amostras do solo nas profundidades de 0-10, 10-20 e 20-40 cm em intervalos de 2,5,8,12,15,18 e 35 dias após aplicação. As amostras de cada profundidade foram tratadas com cloridrato de L-cisteina e acondicionadas sob temperatura de -20C. Através dos resultados obtidos na primeira etapa, pôde-se concluir que o tratamento com cisteina foi eficaz para conservação do analito, tanto para a amostra mantida a -20C quanto para a amostra mantida à temperatura ambiente. Os dados obtidos na segunda etapa do estudo mostraram que mancozebe apresentou comportamento semelhante ao descrito na literatura, para persistência no solo. Os resultados de lixiviação mostraram que nas condições pelas quais foi conduzido o experimento, resíduos de mancozebe foram detectados em profundidades de até 40 cm, porém através dos modelos de potencial de lixiviação, concluiu-se que o fungicida não oferece risco de contaminação de águas subterrâneas

Radiobiological and biochemical investigations of polyoma virus-cell interactions

The cytolytic interaction of Polyoma virus with mouse embryo cells has been studied by radiobiological methods known to distinguish temperate from virulent bacteriophage. No evidence for "temperate" properties of Polyoma was found. During the course of these studies, it was observed that the curve of inactivation of Polyoma virus by ultraviolet light had two components - a more sensitive one at low doses, and a less sensitive one at higher doses. Virus which survives a low dose has an eclipse period similar to that of unirradiated virus, while virus surviving higher doses shows a significantly longer eclipse period. If Puromycin is present during the early part of the eclipse period, the survival curve becomes a single exponential with the sensitivity of the less sensitive component. These results suggest a repair mechanism in mouse cells which operates more effectively if virus development is delayed.

A comparison of the rates of inactivation of the cytolytic and transforming abilities of Polyoma by ultraviolet light, X-rays, nitrous acid treatment, or the decay of incorporated P³², showed that the transforming ability has a target size roughly 60% of that of the plaque-forming ability. It is thus concluded that only a fraction of the viral genes are necessary for causing transformation.

The appearance of virus-specific RNA in productively infected mouse kidney cells has been followed by means of hybridization between pulse-labelled RNA from the infected cells and the purified virus DNA. The results show a sharp increase in the amount of virus-specific RNA around the time of virus DNA synthesis. The presence of a small amount of virus-specific RNA in virus-free transformed cells has also been shown. This result offers strong evidence for the persistence of at least part of the viral genome in transformed cells.

Growth rates of bacteria in rivers

Three different methods for determining bacterial growth rate in rivers are described. Two of the methods are for bacteria in suspension: a recirculating experimental channel method and a radioactive tracer technique using super(35)SO sub(4). The third method is for bacteria attached to surfaces and specifically considers the surface of the common duckweed Lemna minor).

Persistence of viable but non-culturable bacteria during the production and distribution of drinking water

The direct measurement of in situ respiring bacteria using 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) shows that, especially for Gram-negative bacteria, large numbers of viable but non-culturable (VBNC) bacteria are present in finished water from a conventional water treatment plant, and the regrowth of bacteria along distribution networks can be seen rapidly by using this very sensitive technique. The level of bacterial inactivation with chlorine is much less important than has been previously supposed (based on experiments with non-injured laboratory strains of bacteria and classical culture techniques). Threshold values of VBNC bacteria leaving water treatment plants or regrowing along distribution systems have to be determined for better control of coliform regrowth and health- risks associated with the consumption of drinking water.

Physiological Determinants of Invasive Success Linking Distribution Patterns to Metabolic Physiology in Native and Invasive Blue Mussels (genus Mytilus)

In the early 20th century, a blue mussel species from the Mediterranean invaded the California coast and subsequently out-competed the native species south of Monterey Bay. Like other invasive species, Mytilus galloprovincialis has physiological traits that make it successful in habitats formerly occupied by the native M. trossulus, namely its adaptation to warm sea surface temperatures. This study looks at the current genotype distributions and enzymatic activities of field-acclimatized mussels within the hybrid zone where the species co-occur as well as mussels that have been acclimated for four weeks to different temperature and salinity conditions. In the field-acclimatized and laboratory-acclimated mussels, the native species exhibited significantly higher enzyme rates, which may reflect an evolutionary adaptation to compensate to low habitat temperatures. Indeed, the results of the laboratory acclimation indicate that these differences are genetically based. Whether an acclimation capacity exists may require even longer-term acclimation to different temperatures. Current findings suggest that the further spread of the invasive species is likely to be governed in large measure by the potentially counteracting effects of rising temperatures, which would favor the northerly spread of M. galloprovincialis, and increased winter precipitation, which would favor the persistence of M. trossulus. However, the success of M. galloprovincialis during acclimation to ‘dilute’ salinity (25 ppt) suggests that the invasive species can tolerate a greater salinity range than previously thought. Thus, further investigation is needed to build a comprehensive predictive model of the movement of M. galloprovincialis and the hybrid zone along the California coast.

Analysis of the differences between the rates of inflation associated with two aggregate price level: The case of the euro area and the United States

Idioma: Inglés Abstract: This project focuses on two indicators of prices, the GDP deflator and the consumer price index (CPI), and analyzes the differences and similarities they present. These price indexes have been chosen taking into account its great representativeness and importance to economic and social level, and its direct relationship to the overall functioning of the economy and, in particular, inflation. It should be also mentioned that this study was conducted for cases of the euro area and the United States, as the impact of these economies in the economic and social situation at international level is very significant.

An investigation of the recaptures rates for tagged brown trout stocked into the River Ribble

The angling season for non-migratory brown trout, in the Environment Agency (EA) North West Region, runs from March 15th to September 30th. Each year, large numbers of farm reared brown trout are stocked into the rivers of the North West Region's Central Area. In 1994, approximately 20,000 brown trout were introduced into the River systems of the Lune, Wyre and Ribble by local angling clubs and fishery owners. Most of these fish were stocked at a length greater than that defined by local byelaws as the takeable size (200mm). Introductions are made to supplement the existing wild brown trout populations within the river and increase the probability of an angler catching a fish. Stocking with fish of a sufficient length allows the successful angler to remove the catch for their own use. In this way, stretches of the rivers are effectively managed as "put and take" fisheries for brown trout. A number of brown trout fingerlings are also introduced each year by angling clubs and fishery owners. These are stocked with the expectation that the fish will survive in the river to grow, over-winter, and eventually attain a takable size with an increased degree of "wildness". The lower cost of fingerlings, as opposed to trout of a takable length, makes their introduction more attractive to angling clubs since a greater number can be stocked for a given cost. Although the practise of stocking brown trout has occurred for many years in the Central Area, there is little information of its success in terms of increasing anglers catches, or the survival offish introduced. This study was initiated to determine the recapture rates by angling of brown trout following their introduction into a river fishery. The information gained from this study can then be used to give guidance to angling clubs and fishery owners on the optimal strategies for stocking fish.

Surface morphology and properties of zirconia thin films prepared at different deposition rates

ZrO2 thin films were prepared on BK7 glass substrates by electron beam evaporation deposition method. The influence of deposition rate varying from 1.2 to 6.3 nm s(-1) on surface morphology and other properties of ZrO2 films were examined. With increasing deposition rate, the surface defect density increased. The decrease in half width at full maximum in X-ray diffraction pattern with deposition rate indicates an increase in crystal dimension with increasing deposition rate. Electron beam deposited ZrO2 films are known to be inhomogeneous. From the change of the peak transmittance value, it can be deduced that the inhomogeneity of ZrO2 films strengthened gradually with increasing deposition rate. The type of surface defects changed from nodules to craters when the deposition rate was high enough.