901-97 Stroke and Long-term Anticoagulant Therapy in 3404 Post-Myocardial Infarction Patients

In a randomized, double-blind, placebo controlled trial (ASPECT) we studied 3404 post-myocardial infarction patients who suffered a stroke during long-term anticoagulant therapy. The duration of treatment ranged from 1 day to six years. Three years following randomization, 2% of the patients on anticoagulant therapy had a stroke compared to 4% in placebo.The incidence of stroke analyzed on “intention-to-treat” was 0.7 per 100 patient-years in the anticoagulant group and 1.2 per 100 patient-years in placebo, a hazard ratio (HR) of 0.60 with a 95% confidence interval (Cl) of 0.40 to 0.90, a 40% reduction in the risk of stroke in the anticoagulated group. A total of 19 intracranial bleeding was observed. The risk of hemorrhages was 8 times greater for anticoagulated patients compared to placebo. Eight of the 17 bleedings were fatal in the anticoagulant group and no fatal hemorrhages occurred in placebo. A total of 15 cerebral infarctions occurred in the anticoagulated group and 43 in placebo. Of the 14 hemorrhagic strokes, 6 were within INR 3.0–4.0 and 8 with an INR>4.0, Of the 7 non-hemorrhagic strokes, 2 were at INR<2, 3 within INR 3.0–4.0, 1 at INR>4.0, and no measurement was available in one patient. The total number of patients who died or were severely disabled as a result of cerebral stroke amounted to 13 in the anticoagulated group, compared to 18 in placebo.ConclusionThe results of the ASPECT trial indicated that long-term anticoagulant therapy substantially reduced the risk of stroke in post-myocardial infarction patients. The increased risk of bleeding complications associated with anticoagulant therapy was offset by a marked reduction in ischemic events

A GIS for flood risk management in Flanders

In the past decades, Flanders, a region of north Belgium that extends from the coastline inland (in northwest Europe), has suffered several serious riverine floods that caused substantial property damage. As Flanders is one of the most densely populated regions in the world, a solid water management policy is needed in order to mitigate the effects of this type of calamity. In the past, Flemish water managers chose to drain off river water as quickly as possible by heightening the dikes along the rivers. However, this method leads to a higher flood probability further downstream. Moreover, water defence infrastructure can always suffer from technical failures (e.g., breaching) creating even more damage than would have occurred if no defences were in place. In a search for a better solution to this recurring problem, the Flemish administration proposed a new approach in the 1990 s. This approach focuses on minimizing the consequences of flooding instead of attempting to prevent floods. To implement this approach, large amounts of data were gathered for the Flemish Region. Using a Geographic Information System (GIS), a risk-based methodology was created to quantitatively assess flood risk based on hydrologic models, land use information and socio-economic data. Recently, this methodology was implemented in a specifically designed GIS-based flood risk assessment tool called LATIS. By estimating the potential damage and number of casualties during a flood event, LATIS offers the possibility to perform risk analysis quickly and effectively. This chapter presents a concise overview of LATIS’ methodology and its implementation for flood risk management in Flanders

Increase of sentinel lymph node melanoma staging in The Netherlands; still room and need for further improvement

Aim: To investigate implementation of the seventh American Joint Committee on Cancer melanoma staging with sentinel lymph node biopsy (SLNB) and associations with socioeconomic status (SES). Patients & methods: Data from The Netherlands Cancer Registry on patient and tumor characteristics were analyzed for all stage IB-II melanoma cases diagnosed 2010-2016, along with SES data from The Netherlands Institute for Social Research. Results: The proportion of SLNB-staged patients increased from 40% to 65% (p <0.001). Multivariate analysis showed that being female, elderly, or having head-and-neck disease reduced the likelihood of SLNB staging. Conclusion: SLNB staging increased by 25% during the study period but lagged among elderly patients and those with head-and-neck melanoma. In The Netherlands, SES no longer affects SLNB staging performance

A GIS tool for flood risk analysis in Flanders (Belgium)

In the past decades, the low-lying region Flanders (Belgium) has fall victim to numerous flood events, causing substantial damage to buildings and infrastructure. In response to this, the Flemish government proposed a new approach which considers the level of risk as a way for safety measurement. Using geographical information systems, this evolution has lead to a comprehensive risk methodology, and more recently to the development of a flood risk assessment tool called LATIS. By estimating the potential damage and the number of casualties during a flood event, LATIS offers the possibility to perform risk analysis in a fast and effective way. This paper presents a brief overview of the currently used methodology for flood risk management in Flanders and its implementation in the LATIS tool. The usefulness of this new tool is demonstrated by a sequence of risk calculations, performed in the framework of climate change impacts on flood risk in Flanders

The implications of K-Ar glauconite dating of the Diest Formation on the paleogeography of the Upper Miocene in Belgium

The glauconite-rich Diest Formation in central and north Belgium contains sands in the Campine subsurface and the hilly Hageland area that can be distinguished from each other. The Hageland Diest Sands member contains no stratigraphically relevant fossils while in the Campine subsurface dinoflagellate cysts are common and show a stratigraphic range covering the entire Tortonian stage. K-Ar dates were determined for glauconite from 13 selected samples spread over both areas. A glauconite date corresponding to the earliest Tortonian indicates newly formed glauconite was incorporated into a greensand at the base of the Diest Formation in the central Campine area. All other dates point at reworked glauconite and can be organized in two groups, one reflecting a Burdigalian age and another reflecting a Langhian age. These data and the thickness and glauconite content of the Diest Formation imply massive reworking of older Miocene deposits. The paleogeographic implications of these data lead to the tentative recognition of two Tortonian sedimentary sequences. An older one corresponding to dinoflagellate biochron DN8 comprises the Deurne Member, part of the Dessel Member, the Hageland Diest member, the eastern Campine Diest member and some basal sands of the Diest Formation in the central Campine. A younger sequence corresponding to dinoilagellate biochrons DN9 and 10 was strongly influenced by the prograding proto-Rhine delta front in the Roer Valley Graben to the northeast. The subsiding Campine basin was filled from east to west during this second cycle

Automatic and Sampling-Free Parametric Model Order Reduction of Vibro-Acoustic Systems

Recently, a novel parametric model order reduction formulation has been derived for vibroacoustic systems that allows for the reduction of systems with low-rank parametric changes [1]. This scheme does not require sampling of the parameter space, in contrast to conventional parametric model reduction techniques. This means that a single reduction basis, obtained with conventional non-parametric model order reduction schemes, can be used for a wide range of parameter values. This is done by rewriting the system in a non-parametric form, in which the low-rank contributions act as inputs. A disadvantage of this scheme is that the size of the input matrix scales with the amount of chosen parameters, leading to a potentially large reduced basis when many parameters are considered. Therefore, in [2] an automatic Krylov reduction scheme has been proposed that utilizes the similarity in the reduced bases for inputs which are spaced closely together to still get a small reduced basis with a large number of inputs. This is done by using a combination of block second order Arnoldi with a singular value decomposition acting on the resulting basis. The algorithm includes an error estimator that uses a complementary approximation to calculate the error. The main advantages of this algorithm as compared to the commonly used iterative rational Krylov approach [3] are that only a small amount of system inversions are required and that the final reduced order model has the desired predefined relative error in the specified frequency band. In this paper the automatic Krylov reduction scheme and low-rank parametric model order reduction approach are combined and a suitable error estimator is derived, to arrive at compact but accurate parametric reduced order models. The effectiveness is shown with several examples