Amazonian Chironomidae (Diptera, Chironomidae): A contribution to chironomid research in the Neotropics

FABRICIUS described the first two South American Chironomidae in 1805, without naming where they were found. A few years earlier, in 1803, MEIGEN had established the first two genera of today's Diptera family Chironomidae, Tanypus and Chironomus. One hundred years were to go by before Emílio GOELDI discovered the first Chironomidae in the Amazon region and described two species in all their phases of development. Real chironomid research in Brazil, and in particular in Amazonia, did not start until 50 years later. The most comprehensive collection of Amazonian Chironomidae until now was presented at the beginning of the 60s and 70s by the Instituto Nacional de Pesquisas da Amazônia in cooperation with the Max-Planck-lnstitute for Limnology, Plön. This collection is now in the State Zoological Collection in Munich. At present, approximately 650 existing species are known from Central and South America. Only a third of these, 190 species, from tropical South America have been described, the majority using material from the Munich collection. How inadequate our knowledge still is concerning Amazonian Chironomidae is proven by studies of pupal exuviae from the surface drift of a woodland stream in Central Amazonia, which can be assigned to at least 200 chironomid species. We can expect a total far exceeding 1000 chironomid species in Amazonia alone, the occrrence of which appears to be limited to the Neotropics or which belong to endemic South American genera. Information on dispersal patterns for the individual species or their ecological integration in Amazonian waterways is inadequate at present

Crocodiles and the nutrient metabolism of Amazonian waters

The example of the Central Amazonian rain forest is used to illustrate an ecological principle which determines the structure of a tropical ecosystem with a low, but balanced supply of nutrients. This principle implies that the stability of the biocenosis of such a system increases with the abundance and diversity of its species of biota, that is, the degree of differentiation and the size of its biomass. Higher abundance and diversity enable the system to take up the available allochthonous nutrients, to conserve them, and to continuously hold them in shortened nutrient cycles as effìciently as possible. In the Central Amazonian rain forest, we have an extremely large and diverse plant biomass (fresh weight), which assimilates the allochthonous nutrients supplied in the rain. The same principle may also be recognized in the aquatic ecosystems, where the geochemical impoverishment of the Central Amazonian "terra firme" (that land which is not inundated by the annual floods of the main river system) is expressed even more severely than in the terrestrial realm. The low levels of electrolytes in the waters of such systems scarcely permit any primary production, so that here, the food chain is based directly or indirectly on allochthonous organic material. Formation of a strongly differentiated and relatively large biomass, which is mostly due to animals in macroscopic size classes, occurs only where the supply of organic material is relatively great, i.e., in the narrow upper reaches of the streams. A large number of invertebrate animals, especially insect larvae, live on bacteria and fungi. These decompose the materials such as leaves and wood, which are poor in nutrients and not directly available to the fauna. The fishes, which make up most of the biomass act partly as direct filters for the allochthonous materials richer in nutrients, such as insects, flowers, fruit. etc. which are also contributed to the aquatic systems by the forest. As the supply of allochthonous organic material decreases relative to surface area and volume along the courses of the streams, the aquatic biocenosis becomes qualitatively and quantitatively poorer. A new ecological situation arises in the lower reaches, which are annually backed up to form lakes. The main difference is the immigration of brooding fishes from the bordering waters of the main river system, which have high levels of nutrients and primary production. This introduces allochthonous nutrients and permits the existence of a much larger biomass. The "filters" for this periodical supply of nutrients are primarily the caimans, in addition to large piscivorous fishes, turtles, otters and dolphins. In "river-mouth lakes" which have not been disturbed by man, these predators must constitute a large proportion of the biomass. In the Central Amazonian "river lakes", local settlers believe that the fish crops have declined following extermination of the caimans. The ecological interactions which must have existed between caimans and fishes were presented in a previous study. The present work is an attempt to determine whether the amounts of nutrients transferred by the caimans from their largely allochthonous prey, during periods of rapid growth or in longer periods of starvation, are sufficient to influence the ecosystem. The experiments showed that medium-sized caimans daily eat an amount equal to about 0.6 to 0.8 % of their body weight. The total amounts of N, P, Ca, Mg, Na and K released daily under such feeding conditions are about 0.20 to o.27 % of their weight; when the animals are starving, this fraction is reduced to 0.08 to 0.10 % of the body weight. Based on the situation of an hypothetical (but realistic) lake with a surface area of 5 km² and a mean depth of 5 m at medium high water, the following amounts would be released over a 10-day period (in γ/l): a) with good nourishment: N-34, P-9.6, Ca-1.5, Mg-0.1, Na-0.1, K 5..0; b) during starvation: N-17, P-1.5, Ca-0.9, Mg-0.7, Na-0.5, K-1.5. Over the same period the lake would receive in the rain among other materials, (y/l): N-14.9, P-0.4, Ca-5.4, Mg-4.5. The groups of nutrients added by caimans and rain complement each other in the biologically important elements, those which are present in limiting amounts in river water. (River water concentrations in y/l : N-280; P-7, Ca-0, Mg- less than 20). These values show that caimans daily add nutrients (mostly of allochthonous origin) in quantities that are sufficient to enable an elevation of primary production and thereby an enlargement of the autochthonous food chain based on it. With their ability to undergo long periods of starvation, during which accumulated nutrients are continuously released, the animals are especially well adapted to the ecologically extreme environment of the river-lake

Live Trace Visualization for System and Program Comprehension in Large Software Landscapes

The number of software systems in modern enterprise architectures is constantly increasing and thus also the complexity of such software landscapes. In addition, the knowledge of the internal behavior and utilization often gets lost. Software visualization can provide a solution to these challenges. For instance, UML or the city metaphor are established concepts. We utilize these concepts to visualize the communication and entities in a software landscape to ease system comprehension. Our ExplorViz approach visualizes the communication taking place on both the landscape level and the system level. In this paper, we present our PhD project: live trace visualization for system and program comprehension in large software landscapes. For this purpose, our research questions and a sketch of our approach, named ExplorViz, are described. Furthermore, this paper illustrates ideas for the planned evaluation of our approach

Research Perspective on Supporting Software Engineering via Physical 3D Models

Building architects, but also civil or mechanical engineers often build from their designs physical3D models for a better presentation, comprehension, and communication among stakeholders. Software engineers usually create visualizations of their software designs as digital objects to be presented on a screen only. 3D software visualization metaphors, such as the software city metaphor, provide a basis for exporting those on-screen software visualizations into physical models. This can be achieved by 3D-printers to transfer the advantages of real, physical, tangible architecture models from traditional engineering disciplines to software engineering. We present a new research perspective of using physical models to support software engineering. Furthermore, we describe four envisioned usage scenarios for physical models which provide a plethora of new research topics. As proof of concept, we investigate the first usage scenario by evaluating the impact of using physical models on program comprehension in teams through a first controlled experiment. Our experiment reveals that the usage of physical models has a diverging influence. However, they improve the team-based program comprehension process for specific tasks by initiating gesture-based interaction. Therefore, the experiment shows that physical models can provide a promising future research direction

CDOXplorer: Simulation-based genetic optimization of software deployment and reconfiguration in the cloud

Migrating existing enterprise software to cloud platforms involves the comparison of various cloud deployment options (CDOs). A CDO comprises a combination of a specific cloud environment, deployment architecture, and runtime reconfiguration rules for dynamic resource scaling. Our simulator CDOSim can evaluate CDOs, e.g., regarding response times and costs. However, the design space to be searched for well-suited solutions is very large. In this paper, we approach this optimization problem with the novel genetic algorithm CDOXplorer. It uses techniques of the search-based software engineering field and simulations with CDOSim to assess the fitness of CDOs. An experimental evaluation that employs, among others, the cloud environments Amazon EC2 and Microsoft Windows Azure, shows that CDOXplorer can find solutions that surpass those of other state-of-the-art techniques by up to 60\%. Our experiment code and data and an implementation of CDOXplorer are available as open source software

Síolimgía amazoníca n. gen. n. spec., eine flugfähige Chironomide fDiptera) mit einem Hypopygium inversum

Siolimlia amazonica n. gen. n. spec. ist die bisher einzige voll flugfahige Chironomide mit einem Hypopygium inversum. Die Metamorphose weist eine nahe phylogenetische Verwandtschaft mit Goeldichironomus au{. Siolim2ia scheint haufig in produktionsreichen stehenden Gewässern der Tropen Amerikas zu sein und hier oft zur Massenentwicklung zu kommen. In den elektrolytarmen Gewässern Zeniralamazoniens dürfte die neue Art fehlen

Live Trace Visualisierung für System- und Programmverständnis in großen Softwarelandschaften

In many enterprises, the number of deployed applications is constantly increasing. Those applications - often several hundreds - form large software landscapes. The comprehension of such landscapes is frequently impeded due to, for instance, architectural erosion, personnel turnover, or changing requirements. Furthermore, events such as performance anomalies can often only be understood in correlation with the states of the applications. Therefore, an efficient and effective way to comprehend such software landscapes in combination with the details of each application is required. In this thesis, we introduce a live trace visualization approach to support system and program comprehension in large software landscapes. It features two perspectives: a landscape-level perspective using UML elements and an application-level perspective following the 3D software city metaphor. Our main contributions are 1) an approach named ExplorViz for enabling live trace visualization of large software landscapes, 2) a monitoring and analysis approach capable of logging and processing the huge amount of conducted method calls in large software landscapes, and 3) display and interaction concepts for the software city metaphor beyond classical 2D displays and 2D pointing devices. Extensive lab experiments show that our monitoring and analysis approach elastically scales to large software landscapes while imposing only a low overhead on the productive systems. Furthermore, several controlled experiments demonstrate an increased efficiency and effectiveness for solving comprehension tasks when using our visualization. ExplorViz is available as open-source software on www.explorviz.net. Additionally, we provide extensive experimental packages of our evaluations to facilitate the verifiability and reproducibility of our results.In vielen Unternehmen nimmt die Anzahl der eingesetzten Anwendungen stetig zu. Diese Anwendungen - meist mehrere hunderte - bilden große Softwarelandschaften. Das Verständnis dieser Softwarelandschaften wird häufig erschwert durch, beispielsweise, Erosion der Architektur, personelle Wechsel oder sich ändernde Anforderungen. Des Weiteren können Ereignisse wie Performance-Anomalien häufig nur in Verbindung mit den Anwendungszuständen verstanden werden. Deshalb wird ein möglichst effizienter und effektiver Weg zum Verständnis solcher Softwarelandschaften in Verbindung mit den Details jeder einzelnen Anwendung benötigt. In dieser Arbeit führen wir einen Ansatz zur live Trace Visualisierung zur Unterstützung des System- und Programmverständnisses von großen Softwarelandschaften ein. Dieser verwendet zwei Perspektiven: eine Landschaftsperspektive mit UML Elementen und eine Applikationsperspektive, welche der 3D Softwarestadtmetapher folgt. Unsere Hauptbeiträge sind 1) ein Ansatz, genannt ExplorViz, um live Trace Visualisierung von großen Softwarelandschaften zu ermöglichen, 2) ein Überwachungs- und Analyseansatz, welcher in der Lage ist die große Anzahl an Methodenaufrufen in einer großen Softwarelandschaft aufzuzeichnen und zu verarbeiten und 3) Anzeige- und Interaktionskonzepte für die Softwarestadtmetapher, welche über klassische 2D Anzeige und 2D Eingabegeräten hinausgehen. Umfassende Laborexperimente zeigen, dass unser Überwachungs- und Analyseansatz für große Softwarelandschaften elastisch skaliert und dabei nur einen geringen Overhead auf den Produktivsystemen erzeugt. Des Weiteren demonstrieren mehrere kontrollierte Experimente eine gesteigerte Effizienz und Effektivität beim Lösen von Verständnisaufgaben unter Verwendung unserer Visualisierung. ExplorViz ist als Open Source Anwendung verfügbar unter www.explorviz.net. Zusätzlich stellen wir umfangreiche Pakete für unsere Evaluierungen zur Verfügung um die Nachvollziehbarkeit und Wiederholbarkeit unserer Ergebnisse zu ermöglichen