Lichen uses - potentials of the European Guideline for mapping lichen diversity David Svoboda My projects had one common feature, namely the application of the European Guideline for mapping lichen diversity as an indicator of environmental stress (Asta et al. 2002). This methodology was developed in an effort to make a standardised protocol for European screening of epiphytic lichens for various purposes. The dissertation is focused on selected topics and the main objectives can be summarised as follows: 1) To evaluate the potential of the LDV method for determination of general air pollution, and the possibility of applying the new methodology in the Czech Republic. 2) To compare results given by the LDV method and the older qualitative method by Hawksworth and Rose (1970). 3) To determine the principal factors influencing the epiphytic lichen distribution in Central European oak forests, and to elucidate possible correlations among natural and human caused environmental factors in a large scale study. 4) To investigate the epiphytic lichens living in temperate oak forests, their features and possible lichenological differentiations; to determine indicative species for old growth forests and natural woodlands under different climatic conditions and human influence in the Central Europe. 5) To determine...

Acoustic telemetry is an important tool for studying the movement patterns, behaviour, and site fidelity of marine organisms; however, its application is challenged in coral reef environments where complex topography and intense environmental noise interferes with acoustic signals, and there has been less study. Therefore, it is particularly critical in coral reef telemetry studies to first conduct a long-term range test, a tool that provides informa- tion on the variability and periodicity of the transmitter detection range and the detection probability. A one-month range test of a coded telemetric system was conducted prior to a large-scale tagging project investigating the movement of approximately 400 fishes from 30 species on offshore coral reefs in the central Red Sea. During this range test we determined the effect of the following factors on transmitter detection efficiency: distance from receiver, time of day, depth, wind, current, moon-phase and temperature. The experiment showed that biological noise is likely to be responsible for a diel pattern of -on average- twice as many detections during the day as during the night. Biological noise appears to be the most important noise source in coral reefs overwhelming the effect of wind-driven noise, which is important in other studies. Detection probability is also heavily influenced by the location of the acoustic sensor within the reef structure. Understanding the effect of environmental factors on transmitter detection probability allowed us to design a more effective receiver array for the large-scale tagging study.

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Since the 1990s the use of the Internet and electronic commerce (e-commerce) has exploded, yet few SMEs seem to benefit from its potential. The lack of personal involvement and low level of use are an indication that managers still have not committed themselves to e-commerce. Consequently they are not reaping the full benefits first hand. The objectives of the study are to identify key factors and relationships likely to influence e-commerce use by SME managers in the Netherlands and to investigate whether relevant and significant factors can be combined in a new model to predict how SME managers will use new technology. To achieve these objectives, a well-established model of IT usage behaviour, the Technology Acceptance Model (TAM), was used. Building upon TAM, a theoretical research model was developed to investigate a large number of external variables that are possible antecedents of managerial beliefs, attitudes, and the use of IT. E-commerce systems were chosen as the IT tool under review. A cross-sectional field survey was conducted to investigate the theoretical research model. The results are based on the analysis of questionnaire data from 114 managers from Dutch SMEs. Using Structural Equation Modelling (SEM) the results show significant support for external variables, mostly of an individual nature, in the categories of demographics, managerial and IT knowledge, individual characteristics, and company characteristics. Contrary to expectations, two categories - social factors and environmental characteristics - had few or no variables with a significant relationship. This study further presents empirical evidence to suggest a limited number of antecedents under managerial control influencing beliefs, attitudes, and use. A better understanding of the various factors that may impede or increase effective utilization of IT can facilitate the design of organizational or managerial interventions that address these issues. Building on the core TAM model a new model, the e-Tam Model, has been developed based on the results of the theoretical research model. In this model, it is hypothesized that IT usage is directly and indirectly influenced by seven external variables divided into three categories: demographics, personality, and company characteristics. Using the e-Tam Model, effective and increased use of managerial IT tools can be promoted. This will enable managers to have a better use of e-commerce systems leading in turn to better margins and opportunities.

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Growth, mortality, production, spat collection, seasonal cycles of condition index, biochemical composition, carrying capacity of commercial raft culture systems and population genetic characteristics of blue mussel (Mytilus edulis) were studied at different sites in Loch Etive and Loch Kishorn on the west coast of Scotland between May 1993 and May 1995. The main objective of the study was to evaluate current suspended mussel culture production in raft systems and to obtain basic information on the biology and the genetic structure of the two mussel populations in the lochs. There were some water quality differences between the sites in relation to seston, salinity and transparency but not to temperature, particulate organic matter and chlorophylla. When food is available (as particulate organic matter and chlorophyll-a), there was a clear seasonal cycle in mussel somatic growth and shell growth. Mussel growth was relatively high from mid-spring until late autumn, but very slow during the rest of the year. The spring-summer period of rapid shell length and somatic growth coincided with relatively optimum environmental conditions and positive relationships were indicated between growth rates, temperature and salinity, indicating the limiting effect of these two primary factors on growth from late-autumn to mid-spring when there is also a lack of available food. Mussel growth was higher at 2m depth on the raft-rope systems, but in lantern nets experimental growth did not show differences between depths. Growth was found to be similar in the lantern nets and on culture ropes in the two lochs in the first year of experiments (from May 1993 to May 1994). Overall, mean length increments were 31.01mm in Loch Etive and 28.75mm in Loch Kishorn over a 15 month period. The mussels reached marketable size (>50mm) in two years from the known time of spat settlement. A cross-transplantation experiment showed that site rather than stock is the main factor explaining differences in mussel growth in Loch Etive and Loch Kishorn. The position of the mussels within a raft has a significant effect on their growth; mussels at the inflow of a raft have a better growth than those near the outflow (p<0.05) due to greater availability of food. Mean mussel biomass was higher in Loch Kishorn while production was higher in Loch Etive, but there were seasonal and monthly fluctuations in both biomass and production at both sites. Biochemical composition and energy content were similar in both sites, while mussel meat yield and condition indices were significantly higher in Loch Kishom than Loch Etive. Meat content, condition index and carbohydrate values were high during the summer and low from autumn to spring, reaching minimum values in March and April at the time of spawning. Spat settlement occurred in June-July in Loch Etive and June-December in Loch Kishorn. Sea squirt, starfish and eider duck are problems effecting spat collection at the Loch Kishorn site, whereas spat collection in Loch Etive is unaffected by these pests/predators. The carrying capacities for cultured mussels were found to be about 24 metric tons per raft for Loch Etive and 38 metric tons per raft for Loch Kishorn using a particulate organic matter based model; these are reasonable estimates in comparison to the known mussel production levels reported by producers. However, a seston-based model gave an overestimate of carrying capacity for both sites. Cross-transplantation of mussels, electrophoresis and shell morphological measurements showed significant differences between the Loch Etive and Loch Kishorn mussel populations. Mortality rates were higher in transplanted mussels than in the native mussels (p<0.001).

Since the 1990s the use of the Internet and electronic commerce (e-commerce) has exploded, yet few SMEs seem to benefit from its potential. The lack of personal involvement and low level of use are an indication that managers still have not committed themselves to e-commerce. Consequently they are not reaping the full benefits first hand. The objectives of the study are to identify key factors and relationships likely to influence e-commerce use by SME managers in the Netherlands and to investigate whether relevant and significant factors can be combined in a new model to predict how SME managers will use new technology. To achieve these objectives, a well-established model of IT usage behaviour, the Technology Acceptance Model (TAM), was used. Building upon TAM, a theoretical research model was developed to investigate a large number of external variables that are possible antecedents of managerial beliefs, attitudes, and the use of IT. E-commerce systems were chosen as the IT tool under review. A cross-sectional field survey was conducted to investigate the theoretical research model. The results are based on the analysis of questionnaire data from 114 managers from Dutch SMEs. Using Structural Equation Modelling (SEM) the results show significant support for external variables, mostly of an individual nature, in the categories of demographics, managerial and IT knowledge, individual characteristics, and company characteristics. Contrary to expectations, two categories - social factors and environmental characteristics - had few or no variables with a significant relationship. This study further presents empirical evidence to suggest a limited number of antecedents under managerial control influencing beliefs, attitudes, and use. A better understanding of the various factors that may impede or increase effective utilization of IT can facilitate the design of organizational or managerial interventions that address these issues. Building on the core TAM model a new model, the e-Tam Model, has been developed based on the results of the theoretical research model. In this model, it is hypothesized that IT usage is directly and indirectly influenced by seven external variables divided into three categories: demographics, personality, and company characteristics. Using the e-Tam Model, effective and increased use of managerial IT tools can be promoted. This will enable managers to have a better use of e-commerce systems leading in turn to better margins and opportunities.

Throughout the early twentieth century, dengue fever was considered to be a nonthreatening illness, only infecting visitors of the tropics. However, in the last fifty years, there has been a resurgence of dengue fever; it is now considered to be the most consequential arbovirus, infecting more than 50 million people each year and leaving about half of the world's current population at risk of infection. The purpose of this thesis is to explore the various environmental factors that have contributed to the resurgence of dengue fever that has been seen in the last half century. Most notable of these factors are climate change and the increasing urbanization associated with population growth. Specifically, increasing temperatures and precipitation increases the available habitat for the dengue fever vector, the Aedes mosquito, while concurrently increasing both the longevity of the virus and the mosquito. Furthermore, changing sociodemographic factors associated with urbanization have helped spread the mosquito around the world, as the vector largely relies on human transportation. Finally, substandard housing often associated with insufficient water management systems creates the ideal breeding spots for the dengue vector. The Aedes mosquito is known to be one of the most versatile and one of the toughest mosquitoes in the world, which has allowed it to quickly adapt and succeed in these changing environments. Understanding these factors and their influence on the spread of dengue fever is vital in order to effectively manage current and future outbreaks. This is specifically important in regards to dengue fever and severe dengue as no vaccine or medications currently exists to treat this virus.