Distribution and ecology of the stoneflies (Plecoptera) of Flanders (Belgium)

Based on a literature survey and the identification of all available collection material from Flanders, a checklist is presented, distribution maps are plotted and the relationship between the occurrence of the different species and water characteristics is analysed. Of the sixteen stonefly species that have been recorded, three are now extinct in Flanders (Isogenus nubecida, Taeniopteryx nebulosa and T. schoenemundi), while the remaining species are rare. The occurence of stoneflies is almost restricted to small brooks, while observations in larger watercourses are almost lacking. Although a few records may indicate that some larger watercourses have recently been recolonised, these observations consisted of single specimens and might be due to drift. Most stonefly population are strongly isolated and therefore extremely vulnerable. Small brooks in the Campine region (northeast Flanders), which are characterised by a lower pH and a lower conductivity, contained a different stonefly community than the small brooks in the rest of Flanders. Leuctra pseudosignifera, Nemoura marginata and Protonemura intricata are mainly found in small brooks in the loamy region, Amphinemura staandfussi, Isoperla grammatica, Leuctra fusca, L.hippopus, N. avicularis and P. meyeri mainly occur in small Campine brooks, while L. nigra, N. cinerea and Nemurella pictetii can be found in both types. Nemoura dubitans can typically be found in stagnant water fed with freatic water. Sustainable populations of these stonefly species can only be achieved when their present habitats are adequately protected and in addition, measures should be taken to connect and enlarge the remaining populations

Estimating the permeability of reservoir sandstones using image analysis of pore structure

In this thesis, a method is developed for predicting the permeabilities of a core using only a small number of SEM images, without resorting to computationally intensive procedures. The pore structure is idealised as consisting of a cubic network of pore tubes having an arbitrary distribution of cross-sectional areas and shapes. The areas and perimeters of the individual pores are estimated from image analysis of scanning electron micrographs of thin sections, with appropriate stereological corrections introduced to infer the true cross sections of the pores. Effective medium theory is used to find the effective single-tube conductance, based on the measured distribution of individual conductances, thereby allowing a prediction of the permeability. The methodology has been applied to several reservoir sandstones from the North Sea, and also an outcrop sample from Cumbria, UK, yielding predictions that fall within a factor of two of the laboratory measurements in most cases. The procedure, although based on Kirkpatrick's intrinsically isotropic effectivemedium approximation, is not only capable of yielding reasonably accurate estimates of the permeabilities, but also gives a qualitatively correct indication of the anisotropy ratio. It also found that the use of an Bernasconi's anisotropic effective-medium approximation does not lead to a systematic improvement in the results, perhaps because the samples used in this study were insufficiently anisotropic for the approaches to yield different results. The validity of the effective medium approximation was also tested against exact pore network calculations. For the rocks examined in this study, with pore conductance distributions having log-variances less than 3, the effective medium approximation was found to be accurate to within a few percent.Open Acces

Application of decision trees to analyze the ecological impact of invasive species in Polder lakes in Belgium

Polder lakes in Belgium are stagnant waters that were flooded by the sea in the past. Over the years, the salinity of these systems decreased. Several of these systems are colonized by invasive species (often related to fish stocking). The aim of this study was to analyze the ecological impact of invasive macroinvertebrates on native species and to assess to what extend physical-chemical variables affected the presence of invasive species. For this, decision trees were constructed, relating the abiotic lake characteristics to the presence of macroinvertebrates (both invasive and non-invasive). The major advantages of the use of single-target decision trees are the transparency of the rule sets and the possibility to use relatively small databases, since these specific systems were hardly monitored until present

Effect of water quality on waterbugs (Hemiptera: Gerromorpha & Nepomorpha) in Flanders (Belgium) : results from a large-scale field survey

Macroinvertebrates have been collected in Flanders since 1989 by the Flemish Environment Agency to assess ecological water quality. During the present study, the collected waterbugs were identified to species level. In total, more than 90 000 waterbugs were identified, belonging to 45 species. Two of these are recent additions to Flemish fauna: Sigara iactans was found to be a common species in 1989, the first year of monitoring, which is earlier than the first records reported so far, whereas Cymatia rogenhoferi remains a very rare species. Five different communities could be recognized: (1) species occurring in alkaline waters with a high pH, (2) species occurring in colder waters that can tolerate slightly brackish and nutrient rich water, (3) species from running waters, (4) species from acidic waters and (5) ubiquist species that occurred in all types of water. Owing to the general improvement of chemical water quality during the last decade, most species increased, however, three pollution tolerant species declined significantly: Callicorixa praeusta, Corixa punctata and Sigara striata

Credibility in CSR communication: concepts, methods, analyses

In globalized markets, norms for legitimate behavior are scattered and businesses must satisfy often conflicting demands of various stakeholders simultaneously. This is why communicating their Corporate Social Responsibilities (CSR) in a legitimate way is challenging. The present is also a high time for a debate of CSR issues and an era of public scrutiny and mistrust, catalyzed by real-time communication technologies and a 24/7 news cycle. Instances of non-credible communication, the misuse of CSR for marketing exercises, and corporate scandals with large environmental and social impact have sparked skepticism and mistrust toward CSR communication and its tools, particularly CSR reports. As a result, companies and stakeholders are trapped in the “credibility gap” of CSR reporting, which is harmful for both: stakeholders cannot satisfy their information needs regarding CSR and companies can hardly convey their CSR activities in a credible manner. Even though credibility is central to CSR communication and despite the fact that communicating non-credibly has lasting negative consequences for companies, there is no consensus about the concept of credibility and barely any studies exist that tackle credibility gaps systematically. This dissertation endeavors to investigate the issue of credibility in CSR communication theoretically, methodologically, and empirically. In particular, it analyzes companies’ and stakeholders’ perspectives of the “credibility gap” in CSR reporting. It explores concepts and methods to investigate how companies can communicate credibly and provides empirical evidence on the state-of-the-art of CSR reporting in Europe. To this end, it combines concepts from business ethics, management studies, political theory, and communication sciences and triangulates various methods. This dissertation is structured in four individual chapters framed by an introductory part and conclusions. The key findings can be summarized as follows. Chapter I proposes that communication is at the heart of CSR by highlighting Habermasian communicative action theory as the backbone of political CSR theory. Furthermore, it discusses how credible CSR communication leads to moral legitimacy and thus provides the conceptual foundation of this dissertation. Based on this theoretical advancement, the chapter develops a typology of CSR communication tools clustering them into deliberative and instrumental as well as published and unpublished tools. Chapter II presents quantitative content analysis as a suitable method to generate novel insights in business ethics, and especially CSR, research. Given the diametrical advantages of human- and software-based coding procedures, a concurrent mixed methods approach is proposed. To account for the need of ethical reasoning in business ethics research, the chapter suggests that quantitative content analyses be followed by an ethical interpretation of the quantitative results. Chapter III analyzes, for the first time, the “credibility gap” in CSR reporting from the perspective of the company, by applying quantitative content analysis as proposed in Chapter II. To this end, the credibility of CSR reports from 11 European countries is analyzed based on a multidimensional operationalization of credibility along Habermasian theory. Parametric statistical analyses reveal that European CSR reports are credible at a mediocre level. It is the content of the reports that matter for credibility, while the impact of contextual, format, and firm-level factors is secondary. Furthermore, voluntary standardization impacts credibility positively, whereas legislation does not yet have the same positive effect. Addressing the stakeholders’ perspective, Chapter IV develops a measurement scale to test the perceptions of credibility of CSR reports. In doing so, the chapter builds on a novel conceptualization of credibility along the Habermsian validity claims. The scale development comprises nine stages including a literature review, a delphi study, and three validation studies applying exploratory and confirmatory factor analyses to arrive at the final 16-item PERCRED (perceived credibility) scale. Participants in the final study perceived CSR reports to be rather credible, regardless of whether the same reports had been found credible or non-credible in Chapter III. The PERCRED measure can help companies and researchers deepen the understanding of why CSR reports are often perceived as being non-credible tools. The findings of this dissertation demonstrate that the “credibility gap” equally exists from the companies’ and the stakeholders’ perspectives. To eventually bridge it, striving for true, sincere, appropriate, and understandable communication by all parties is a viable avenue. Describing credibility as a communication quality and perception construct along the four sub-dimensions truth, sincerity, appropriateness, and understandability advances the understanding of credibility in the communication sciences. This dissertation contributes to theory development in the emerging field of CSR reporting by presenting credible CSR reports as facilitators to re- and maintain legitimacy and by systematically examining this notion from the perspective of companies and stakeholders. The thesis further advances political CSR theory as it empirically confirms the impact of voluntary standardization and stresses the role of the nation state. The findings of this dissertation also hold implications for public policy makers to level the playing field in CSR reporting in order to reach credibility consistently; companies are provided with a tool to measure credibility perceptions of their reports and to better evaluate the roots of stakeholders’ criticism and mistrust

First occurrence of the Ponto-Caspian amphipod Echinogammarus trichiatus (Martynov, 1932) (Crustacea: Gammaridae) in Belgium

The Ponto-Caspian amphipod species Echinogammarus trichiatus (Martynov, 1932) was found in Belgium for the first time in June 2009 at two different locations in an artificial lake bordered by two large canals. Adults as well as juveniles were found in small numbers and occurred together with several other Ponto-Caspian species such as Dikerogammarus villosus (Sowinsky, 1894) and Dreissena polymorpha (Pallas, 1771). An identification key to the genus Echinogammarus of inland waters in Western Europe is provided. This first record of yet another new amphipod invader in Belgium demonstrates the continuous introduction of alien species into West European waters

Revealing the intricacies of cancer

A report on the 14th Lorne Cancer Conference, Lorne, Victoria, Australia, 14-17 February 2002

Alien macro-crustaceans in freshwater ecosystems in Flanders

During the last decades, the spread of aquatic alien species has increased enormously. Range extensions of exotic species have been facilitated by the interconnection of river basins and increased shipping. Invasive species are considered as an important component in the decline of diversity of communities and the abundance of other species in freshwater ecosystems. Besides their ecological impact, alien species are considered to cause worldwide economical damage. Currently, eighteen alien macro-crustaceans have been found in freshwater ecosystems in Flanders. One of these invasive species is the Ponto-Caspian invader Dikerogammarus villosus, which has invaded most of Europe since the beginning of the 1990s, mainly as result of the opening of the Main-Danube canal. This species was recorded for the first time in the east of Flanders in 1997. In order to assess the potential effect of this species on other macroinvertebrates, laboratory experiments as well as field observations were conducted. All types of prey that were used in predator-prey experiments were consumed by D. villosus, especially species that were less mobile such as Chironomidae. Substrate preference experiments indicated that D. villosus preferred a stony substrate. Using decisions trees to model field observations, it could be concluded that D. villosus could mainly be found in habitats with an artificial bank structure, a high oxygen concentration and a low conductivity, which corresponds with the canals where it has been observed mostly in Flanders

Chimeric Antigen Receptor T Cell Research For Clinical Applications

Genetically engineered T cells are a promising therapeutic tool for the treatment of cancer or infectious diseases. The generation of potent chimeric antigen receptor (CAR) T cells for clinical use, however, is associated with a plurality of challenges covering medical, economical as well as scientific aspects. Therefore, the present study focusses on specific medical and technical difficulties limiting the dissemination of adoptive cellular therapies (ACT). Furthermore, strategies aiming to improve the potential of CAR modified T cells, especially in a solid tumor setting, were investigated. To this effect, our work initially focused on the generation of a novel CD20-directed CAR which we evaluated in newly established in vitro and in vivo assays. After confirming the potency of the anti-CD20 CAR T cells, we focused on the manufacturing and consequently demonstrated that a current good manufacturing practice (cGMP)-compliant, automated T cell Transduction (TCT) Process is both reliable and applicable to manufacture CAR T cells in a clinically relevant scale and quality. Despite varying starting material, different operators or the use of other devices, the developed manufacturing process yielded a robust formulated product with regard to cellular composition, T cell phenotype or anti-tumor potency. Overall, the high reproducibility of the TCT Process proved the suitability to manufacture CD20-directed CAR T cells which are intended to be used in two clinical trials. In addition, this work focused on strategies to enhance the CAR-based immune response in a melanoma model by co-expressing a CAR and a chimeric co-stimulatory receptor (CCR) in the same T cell. This two-receptor approach includes a second generation CAR specific for chondroitin sulfate proteoglycan 4 (CSPG4) and a CCR that recognizes CD20. Here we show that, dependent on intracellular CCR design, only a simultaneous activation of both co-expressed chimeric receptors CAR as well as CCR resulted in a significantly enhanced immune response. Altogether, this data supports the idea of using an anti-CD20 CCR as a tool to increase the potential of CAR T cells