Knowledge and Learning in Complex Urban Renewal Projects; Towards a Process Design

Urban Renewal is carried out to renovate, demolish and rebuild houses in problematic urban areas. Urban renewal processes are complex; many actors are involved, the goals and strategies of these actors can change over time, and contextual factors (such as the housing market, residents’ wishes, the political direction) change constantly. This creates a lot of uncertainty in urban renewal processes; uncertainty about knowledge and values (substantive uncertainty), uncertainty about the intentions and strategies of the parties involved (strategic uncertainty), and uncertainty about when, where and by whom decisions are made (institutional uncertainty). With learning, this uncertainty can be made more manageable. The creation, sharing, use and evaluation of knowledge in urban renewal networks helps to respond to changes in, amongst others, residents’ wishes, the housing market, and technological developments. Learning can be defined as the creation of knowledge that is applicable in the activities of the parties involved. In urban renewal, four important steps towards learning can be recognised: the (collective) development of knowledge, the mutual sharing of knowledge, the use of the relevant knowledge available, and the evaluation of the knowledge gathered. A complex urban renewal project has been studied in the second largest Dutch city; Rotterdam, in the district ‘Hoogvliet’. This case study, that has an explorative character, exists of interviews with professionals working on urban renewal in Hoogvliet and observations during meetings at several levels of the cooperation network. Preliminary findings suggest that the development and sharing of knowledge in urban renewal in Hoogvliet takes place mainly through face-to-face contact, for instance during meetings and debates, and not so much in writing, for instance in databases or guidebooks. Another finding is that for collective learning to occur, a minimum of collective knowledge is needed; the parties involved must know the basics of the tasks and responsibilities of the other parties and of the knowledge built up earlier in the process. Furthermore, to increase the potential for learning, it seems smarter to sketch the outlines of complex long-term projects and concretize these along the way, then to make detailed plans far in advance.

Film documentary : nodding syndrome: an illness in the making

This film documentary is based on fifteen months of anthropological fieldwork in northern Uganda and shows the complexity of nodding syndrome and the many different narratives, explanatory models and coping styles regarding this affliction. In attempting to understand what nodding syndrome is and how it is experienced, we should look at the context in which meaning making takes place

3PAC: Enforcing Access Policies for Web Services

Web services fail to deliver on the promise of ubiquitous deployment and seamless interoperability due to the lack of a uniform, standards-based approach to all aspects of security. In particular, the enforcement of access policies in a service oriented architecture is not addressed adequately. We present a novel approach to the distribution and enforcement of credentials-based access policies for Web services (3PAC) which scales well and can be implemented in existing deployments

The quest for treatment: the violated body of nodding syndrome in Northern Uganda

Nodding syndrome is an unexplained affliction that affects thousands of children in northern Uganda. It is characterised by episodes of repetitive dropping forward of the head and often accompanied by convulsions. Symptoms were first reported in Uganda around 1998, during two decades of violent conflict between the Lord’s Resistance Army and Ugandan government. Violence and politics have been assimilated into local narratives on nodding syndrome and illness experiences are connected to the trauma of past conflict. This paper provides insight into how narratives on nodding syndrome are affected by the experience of conflict and how they in turn shape responses to illness. Attention is paid to the complex politics of illness and healing in the context of a pluralistic medical system

Level-Set Based Artery-Vein Separation in Blood Pool Agent CE-MR Angiograms

Blood pool agents (BPAs) for contrast-enhanced (CE) magnetic-resonance angiography (MRA) allow prolonged imaging times for higher contrast and resolution. Imaging is performed during the steady state when the contrast agent is distributed through the complete vascular system. However, simultaneous venous and arterial enhancement in this steady state hampers interpretation. In order to improve visualization of the arteries and veins from steady-state BPA data, a semiautomated method for artery-vein separation is presented. In this method, the central arterial axis and central venous axis are used as initializations for two surfaces that simultaneously evolve in order to capture the arterial and venous parts of the vasculature using the level-set framework. Since arteries and veins can be in close proximity of each other, leakage from the evolving arterial (venous) surface into the venous (arterial) part of the vasculature is inevitable. In these situations, voxels are labeled arterial or venous based on the arrival time of the respective surface. The evolution is steered by external forces related to feature images derived from the image data and by internal forces related to the geometry of the level sets. In this paper, the robustness and accuracy of three external forces (based on image intensity, image gradient, and vessel-enhancement filtering) and combinations of them are investigated and tested on seven patient datasets. To this end, results with the level-set-based segmentation are compared to the reference-standard manually obtained segmentations. Best results are achieved by applying a combination of intensity- and gradient-based forces and a smoothness constraint based on the curvature of the surface. By applying this combination to the seven datasets, it is shown that, with minimal user interaction, artery-vein separation for improved arterial and venous visualization in BPA CE-MRA can be achieved

A relation between circumnuclear HI, dust, and optical cores in low-power radio galaxies

From new observations and literature data we investigate the presence of HI, dust, and optical cores in the central kiloparsec of low-power radio galaxies. The goal of this pilot study is to identify physical relations between these components, which can help us to study kinematics and feeding mechanisms in future samples of active galaxies. Our results are consistent with neutral gas being associated with dust on sub-kiloparsec scales. Objects that have HI absorption always have significant amounts of dust in their host galaxy. If there is no visible dust in the host galaxy, there is also no HI absorption. The presence of an unresolved optical core correlates with the HI column density, with the core being absent in high column density sources. This work opens a path for studying the kinematics of cold material in the central regions of active galaxies by combining information of HI absorption and molecular lines. Consistent with previous work, we find no evidence for a compact, parsec-scale obscuring torus in low-power radio galaxies.Comment: Accepted for publication in A&

Chromatin Flavors: Chromatin composition and domain organization in Drosophila melanogaster

Chromatin was originally identified by W. Flemming in 1882 as not much more than the stainable substance of the cell nucleus. Flemming named this substance according to the Greek word “chroma”, meaning color. In 1911 chromatin was characterized as proteins, named histones, that were attached to nucleic acid (DNA). In the following years it became clear that chromatin formed the structural basis of genetic information. Not until more than 30 years later the DNA, and not the histone proteins as was widely expected, was identified as the carrier of the genetic information. In 1952 the role of DNA in inheritance was confirmed and not much later Watson and Crick discovered the double-helical structure of DNA based on the DNA crystal analyses of Franklin, Gosling and Wilkins