Simulation of ecological impacts of the new outer-harbour development in Zeebrugge

The new outer-harbour in Zeebrugge is to be protected by jetties extending 1,750 m seaward, This development will alter the local distribution of tidal and residual currents. Such hydrodynamic changes will, in turn, affect the dispersion pattern of dissolved and particular matters in the vicinity of Zeebrugge. A mathematical model is presented, which simulates the dispersion - before and after outer harbour development - of dissolved organic matters, faecal bacteria and heavy metals, which are indicative of, respectively domestic, human, and industrial pollutions

Processing oblique aerial photographs in Flanders: the Havik Project at the Ghent University. A contribution to archaeological resource management

A contribution to archaeological resource management. Ghent University has organised an archaeological aerial survey of both provinces of East- and West-Flanders since the beginning of the 1980s. As a result of these activities, some 50,000 photographs have been captured. They reveal thousands of archaeological structures, from the Neolithic through to the most recent periods. Since 1997, financial support has been received from the Flemish Community aimed at the realisation of a GIS based database (Access 97 relational database - Arcview 3.1) and the digitalisation of some 50% of the photographs. As a result, it was possible to locate all 50,000 images and connect them with geographical information offered by the support centre GIS Flanders. It is expected in the near future that this information will be available for SMR-purposes and archaeological heritage management. There are also several scientific outputs: one of them is the study of Bronze Age barrows

Multiple-model based update of belgian reference road data

This paper describes a semi-automatic system for road update based on high resolution orthophotos and 3D surface models. Potential update regions are identified by an object-wise verification of all existing database records, followed by a scene-wide detection of redevelopment regions. The proposed system combines several road detection and road verification approaches from current literature to form a more general solution. Each road detection / verification approach is realized as an independent module representing a unique road model combined with a corresponding processing strategy. The object-wise verification result of each module is formulated as a binary decision between the classes "correct road" and "incorrect road". These individual decisions are combined by Dempster-Shafer fusion, which provides tools for dealing with uncertain and incomplete knowledge about the statistical properties of the data. For each road detection / verification module a confidence function for the result is introduced that reflects the degree of correspondence of an actual test situation with an optimal situation according to the underlying road model of that module. Experimental results achieved with data from the national Belgian road database in a test site of about 134 km(2) demonstrate the potential of the method

Topological effects in ring polymers: A computer simulation study

Unconcatenated, unknotted polymer rings in the melt are subject to strong interactions with neighboring chains due to the presence of topological constraints. We study this by computer simulation using the bond-fluctuation algorithm for chains with up to N=512 statistical segments at a volume fraction \Phi=0.5 and show that rings in the melt are more compact than gaussian chains. A careful finite size analysis of the average ring size R \propto N^{\nu} yields an exponent \nu \approx 0.39 \pm 0.03 in agreement with a Flory-like argument for the topologica interactions. We show (using the same algorithm) that the dynamics of molten rings is similar to that of linear chains of the same mass, confirming recent experimental findings. The diffusion constant varies effectively as D_{N} \propto N^{-1.22(3) and is slightly higher than that of corresponding linear chains. For the ring sizes considered (up to 256 statistical segments) we find only one characteristic time scale \tau_{ee} \propto N^{2.0(2); this is shown by the collapse of several mean-square displacements and correlation functions onto corresponding master curves. Because of the shrunken state of the chain, this scaling is not compatible with simple Rouse motion. It applies for all sizes of ring studied and no sign of a crossover to any entangled regime is found.Comment: 20 Pages,11 eps figures, Late

AC losses and critical current density of superconducting GdBa2Cu3O7−x

Energy losses occurring in a cylindrical sample of Gd-Ba-Cu-O, subjected to an external AC magnetic field were examined. The loss dependence on the amplitude of the magnetic induction exhibits two stages of flux penetration into the superconductor. Critical current densitities for both stages of penetration were examined and an explanation for such behaviour is proposed. Support for this point of view is obtained by measurements on pulverized sample material. All measurements were performed at a temperature of 4.2 K and in absence of a background field.\ud \ud Analysis of the data provides two critical current densities: an inter-granular critical current density at weak alternating magnetic fields and an intra-granular critical current density at higher magnetic fields. The intra-granular critical current density is at least two orders of magnitude larger than the inter-granular one

Contribution of Primary Pelvic Organ Prolapse to Micturition and Defecation Symptoms

Objective. To investigate the contribution of Pelvic Organ Prolapse (POP) to micturition and defecation symptoms. Method. Cross-sectional study including 64 women presenting with POP symptoms and 50 controls without POP complaints. Subjects were evaluated using POP-Quantification system, Urinary Distress Inventory, and Defecation Distress Inventory. The MOS SF-36 health survey and the Center for Epidemiological Studies Depression scale were used to measure self-perceived health status and depressive symptoms, respectively. Results. POP in terms of POP-Q had a moderate impact on the symptom observing vaginal protrusion (explained variance 0.31). It contributed modestly to obstructive voiding and overactive bladder symptoms (explained variance 0.09, resp., 0.14) but not to urinary incontinence. Constipation was more likely explained by clinical depression than by pelvic floor defects (explained variance 0.13, resp., 0.05). Conclusion. Stage of POP and specific prolapse symptoms are associated but such a strong association does not exist between POP and micturition or defecation symptoms

Polydisperse star polymer solutions

We analyze the effect of polydispersity in the arm number on the effective interactions, structural correlations and the phase behavior of star polymers in a good solvent. The effective interaction potential between two star polymers with different arm numbers is derived using scaling theory. The resulting expression is tested against monomer-resolved molecular dynamics simulations. We find that the theoretical pair potential is in agreement with the simulation data in a much wider polydispersity range than other proposed potentials. We then use this pair potential as an input in a many-body theory to investigate polydispersity effects on the structural correlations and the phase diagram of dense star polymer solutions. In particular we find that a polydispersity of 10%, which is typical in experimental samples, does not significantly alter previous findings for the phase diagram of monodisperse solutions.Comment: 14 pages, 7 figure