Do contaminants originating from state-of-the-art treated wastewater impact the ecological quality of surface waters?

Since the 1980s, advances in wastewater treatment technology have led to considerably improved surface water quality in the urban areas of many high income countries. However, trace concentrations of organic wastewater-associated contaminants may still pose a key environmental hazard impairing the ecological quality of surface waters. To identify key impact factors, we analyzed the effects of a wide range of anthropogenic and environmental variables on the aquatic macroinvertebrate community. We assessed ecological water quality at 26 sampling sites in four urban German lowland river systems with a 0–100% load of state-of-the-art biological activated sludge treated wastewater. The chemical analysis suite comprised 12 organic contaminants (five phosphor organic flame retardants, two musk fragrances, bisphenol A, nonylphenol, octylphenol, diethyltoluamide, terbutryn), 16 polycyclic aromatic hydrocarbons, and 12 heavy metals. Non-metric multidimensional scaling identified organic contaminants that are mainly wastewater-associated (i.e., phosphor organic flame retardants, musk fragrances, and diethyltoluamide) as a major impact variable on macroinvertebrate species composition. The structural degradation of streams was also identified as a significant factor. Multiple linear regression models revealed a significant impact of organic contaminants on invertebrate populations, in particular on Ephemeroptera, Plecoptera, and Trichoptera species. Spearman rank correlation analyses confirmed wastewater-associated organic contaminants as the most significant variable negatively impacting the biodiversity of sensitive macroinvertebrate species. In addition to increased aquatic pollution with organic contaminants, a greater wastewater fraction was accompanied by a slight decrease in oxygen concentration and an increase in salinity. This study highlights the importance of reducing the wastewater-associated impact on surface waters. For aquatic ecosystems in urban areas this would lead to: (i) improvement of the ecological integrity, (ii) reduction of biodiversity loss, and (iii) faster achievement of objectives of legislative requirements, e.g., the European Water Framework Directive

Zu philosophischen Problemen der weiteren Entfaltung von Triebkraeften sozialistischer Kulturentwicklung unter Beruecksichtigung der Leitungs- und Erziehungstaetigkeit in den Museen, Gedenkstaetten und Sammlungen der Stadt Magdeburg

DB Leipzig(101) - Di1990 B 7645, T. 1, 2 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Der FDBS-Demonstrationsprototyp SIGMA _D_E_M_O

SIGLEAvailable from TIB Hannover: RR 4487(1997,3) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekKultusministerium des Landes Sachsen-Anhalt, Magdeburg (Germany)DEGerman

Absorption probabilities of a Brownian motion in a triangular domain

The absorption probabilities of a twodimensional Brownian motion with independend components in a triangular domain are evaluated for special parameter cases. After proving a twodimensional functional limit theorem, the results are obtained from a known random walk result. (orig.)Available from TIB Hannover: RR 4487(1996,17) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

The absorption time of a Brownian motion between an absorbing and a reflecting barrier as a limit of random walk results

While the distribution of the absorption time of a Brownian motion starting in a fixed point between an absorbing and reflecting barrier is known as a result of a differential equation, it is shown in this paper that this distribution can also be obtained as a limit of random walk results. (orig.)Available from TIB Hannover: RR 4487(1996,18) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Positivity for polyharmonic problems on domains close to a disk

SIGLEAvailable from TIB Hannover: RR 4487(2004,19) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Anwendungskonzepte fuer die rechnerunterstuetzte integrierte Produktion. Entwicklung und Transfer fuer die personelle, organisatorische und technische Gestaltung eines Bereiches der auftragsgebundenen Einzel- und Kleinserienfertigung eines Dieselmotorenherstellers auf dem Gebiet der ehemaligen DDR Schlussbericht

SIGLEAvailable from TIB Hannover: F95B926+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Metrics-based evaluation of object-oriented software development methods

The efficiency of software development (i.e. to produce good software products based on an efficient software process) must be controlled by a quantification of the software development methodologies. The description of object-oriented (OO) methods or comparisons of some of these methods are usually given by a listing of their features. These presentations describe the functionality of a particular development method, but often fail to address quality issues like efficiency, maintainability, portability, maturity etc. The quantification by means of software measurement needs a unified strategy, methodology or approach as one important prerequisite to guarantee the goals of quality assurance, improvement and controlled software management to be achieved. Nowadays, plenty of methods such as measurement frameworks, maturity models, goal-directed paradigms, process languages etc. exist to support this idea. This paper describes an object-oriented approach of a software measurement framework aimed at evaluating OO development methods themselves. It reasons the applicability of metrics-based evaluation as indicator for the quality assurance of the OO development process. (orig.)Available from TIB Hannover: RR 4485(1997,10) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman