How to incorporate prior information in geophysical inverse problems: deterministic and geostatistical approaches.
Hermans, Thomas ; Caterina, David ; et al
in EarthDoc - Near Surface 2011 - 17th European Meeting of Environmental and Engineering Geophysics (2011, September 13)
Many geophysical inverse problems are ill-posed leading to non-uniqueness of the solution. It is thus important to reduce the amount of mathematical solutions to more geologically plausible models by ... [more ▼]
Many geophysical inverse problems are ill-posed leading to non-uniqueness of the solution. It is thus important to reduce the amount of mathematical solutions to more geologically plausible models by regularizing the inverse problem and incorporating all available prior information in the inversion process. We compare three different ways to go beyond standard Occam’s inversion for electrical resistivity tomography (ERT) using electromagnetic logging data in the context of salt water infiltration: a simple reference model, a structural constraint and a geostatistical constraint based on a vertical correlation length. Results with the traditional smoothness constraint yield small contrasts of resistivity, far from the reality revealed by borehole measurements. Incorporating prior information from boreholes clearly improves the misfit with logging data. If a good reference model can always be used, it can lead to misinterpretation if its weight is too strong. When the computation of the correlation length is possible, the geostatistical inversion gives satisfactory results everywhere in the section. In this specific case, the geostatistical approach seems to be a more robust way to incorporate prior information. The structural constraint seems to be more indicated when integrating information from other geophysical methods such as GPR or seismic. [less ▲]Detailed reference viewed: 531 (26 ULg)
How to increase species diversity in phytostabilization strategies near Lubumbashi (D.R.C.)
Boisson, Sylvain ; Collignon, Julien ; Le Stradic, Soizig et al
Conference (2013, October 08)
Copper contamination of soils represents a threat to natural areas and to human health. Phytostabilization, i.e using plants to immobilize contaminants, represents a well-known technology to hemper heavy ... [more ▼]
Copper contamination of soils represents a threat to natural areas and to human health. Phytostabilization, i.e using plants to immobilize contaminants, represents a well-known technology to hemper heavy metals spread across landscapes. In Katanga (Congo D.R.), Microchloa altera was recently identified as a candidate species to stabilize copper in soil. This grass naturally tolerates and accumulates high copper concentrations and belongs to the typical copper flora of Katanga. However more than 600 species compose this flora and other grasses may be used in phytostabilisation strategies. But little is known about the phenology reproductive strategy and demography of these species, which makes their use in current phytostabilization strategies difficult. The present study aims to characterize the reproduction capacity of seven other dominant grass species for future phytostabilisation tests. A total of 67 quadrats (1m²) were randomly placed across three sites. At two periods over the fruiting season, three inflorescences per species per quadrat were collected in order to estimate the number of spikes, spikelets and viable seeds. All species have sexual reproductive strategy and spikelets number presents little variation between populations. Three species are very common (Andropogon shirensis, Loudetia simplex and Eragrostis racemosa) and represent potential candidates to increase species diversity in phytostabilization strategies in Katanga. Further research, including germination tests and phytostabilization tests in situ, is planned in a near future. [less ▲]Detailed reference viewed: 80 (17 ULg)
How to increase your impact with Open Access. Bruxelles, 13 février 2007 [compte rendu]
in Cahiers de la Documentation = Bladen voor Documentatie (2007), 61(2), 40-42
Compte rendu de la journée nationale "How to increase your impact with Open Access" du 13 février 2007.Detailed reference viewed: 72 (17 ULg)
How to integrate into a disintegrating country? Intercultural Dialogue in Belgium in the last two decades
Conference (2011)Detailed reference viewed: 15 (0 ULg)
How to introduce "Geography" into databases?
Scientific conference (2004, April 21)
Form and content of spatial data. Geographic versus cartographic data? Software solutions: mapping software, Desktop GIS, Enterprise GIS. Database models: Flat relational, Spatial-enabled database ... [more ▼]
Form and content of spatial data. Geographic versus cartographic data? Software solutions: mapping software, Desktop GIS, Enterprise GIS. Database models: Flat relational, Spatial-enabled database. Required standards. GIS architecture today. [less ▲]Detailed reference viewed: 19 (0 ULg)
How to involve stakeholders in CSR certifications?
El Abboubi, Manal ; Cornet, Annie
Conference (2008, May)Detailed reference viewed: 69 (4 ULg)
How to locate intermodal terminals for achieving economic and environmental competitiveness?
Mostert, Martine ; Limbourg, Sabine
Conference (2014, April 25)
Europe has a strong commitment to the development of competitive and sustainable transportation. An intermediate objective cited in the “White Paper” is to shift 30% of 300 km and above road freight ... [more ▼]
Europe has a strong commitment to the development of competitive and sustainable transportation. An intermediate objective cited in the “White Paper” is to shift 30% of 300 km and above road freight transportation to more environmentally-friendly modes of transport such as rail and water by 2030. Improving and expanding the intermodal network is one way to achieve this goal. However, intermodal transport requires intermodal terminals where the transfer from one mode to another can occur. The location of those terminals is of strategic importance for the competitiveness of intermodal transport. The objective of this paper is therefore to develop a network design model which allows the optimal location of intermodal terminals to be determined, subject to both economic and environmental efficiency. Three possible combinations are considered: (i) Road-only, (ii) Intermodal transport using road (drayage) and rail (long-haul) and (iii) Intermodal transport using road (drayage) and inland waterways (long-haul). External costs are also included in the analysis, i.e. costs that are generated by an economic agent but supported by other agents of the society. This strategy is in line with the willingness of Europe to internalize external costs. The developed model can be used to test how modal split is influenced by the undertaken policies, such as internalizing external costs in the transportation costs. Tests are carried out on the case study of Belgium. [less ▲]Detailed reference viewed: 59 (8 ULg)
How to make a bear dropping attractive? Molecular non-invasive methods in conservation genetics
Scientific conference (2007, January 12)Detailed reference viewed: 8 (0 ULg)
How to make good use of a “bad” enzyme: utilization of efficient β-lactamases for the benefits of biochemical research
Vandevenne, Marylène ; Galleni, Moreno ;
in Frère, Jean-Marie (Ed.) β-lactamases (2012)Detailed reference viewed: 18 (1 ULg)
How to make Natura 2000 work properly? : Socio-economic, legal & ecological management
; ; et al
Poster (2008, September)
In Belgium, the delineation of Special Protection Areas (SPA) and Special Areas of Conservation (SAC) has been done. At present many questions arise concerning the management of these areas. The multiple ... [more ▼]
In Belgium, the delineation of Special Protection Areas (SPA) and Special Areas of Conservation (SAC) has been done. At present many questions arise concerning the management of these areas. The multiple use of the space generates conflicts of interest. The SELNAT-project aims to answer the question “How to make Natura 2000 work properly?”, taking into account socio-economic, legal and ecological management aspects. This project aims to achieve more insight in a sustainable management of Natura 2000 sites. In a first part of the study, the legal framework, the ecological status and the socio-economic frame have been described. The main legal, economic, social and ecological bottlenecks for the Natura 2000 network implementation in Belgium have been highlighted. In a next phase, guidelines for the elaboration of a ‘good management plan’ for the Natura 2000 network will be developed at the local scale taking into account the principles of the Ecosystem approach.. The fundamental question in this part is which instruments are needed at what time in the implementation process to reach the ecological targets taking into account economic, legal and social considerations. In a first step we evaluated the feasibility and effectiveness of these instruments by means of a literature review and a survey among experts of the field. In a second step we’ll try to develop a management plan for two case study areas, a Flemish site and a Walloon site. A the end of the project, recommendations for policy makers about the improvement of these instruments will be formulated. [less ▲]Detailed reference viewed: 23 (2 ULg)
HOW TO MAKE NATURA 2000 WORK PROPERLY? : SOCIO-ECONOMIC, LEGAL AND ECOLOGICAL MANAGEMENT : "SELNAT"
; ; et al
This report includes results obtained from the SELNAT research project, conducted between February 2006 and January 2008, under the auspices of the Belgian Science Policy. The principal subject of this ... [more ▼]
This report includes results obtained from the SELNAT research project, conducted between February 2006 and January 2008, under the auspices of the Belgian Science Policy. The principal subject of this project is the implementation of Natura 2000. The Natura 2000 network of protected areas, made up of sites designated under the Community Birds (BD) and Habitats Directives (HD), is a key pillar of action for the conservation of biodiversity (European Commission, 2008). It is central to achieve the commitment to reverse the decline of biodiversity in the European Union by the year 2010 made at the European Council meeting in Gothenburg in June 2001. It aims at sustainable conservation of habitats and species of community importance, taking into account (i) economic, social and cultural requirements and (ii) regional and local circumstances. Central to the Directives is the creation of a Europe-wide ecological network of protected sites – the Natura 2000 Network – which is destined to conserve over a thousand rare, threatened and endemic species and some 220 Natural habitats listed in their annexes. Around 24,000 sites have been included in the Network so far. (European Commission, 2008) Now that the network set-up is nearing completion, there is a need to increase the focus on the active management of the sites so as to ensure long-term conservation and the achievement of the economic and social objectives of the network (CEE, 2004.) This in turn also raises the question of finding the appropriate management strategy, instruments and sufficient financing (at all levels). The principal question for Member States is how to manage Natura 2000 sites to reach the (juridical fixed) ecological targets in the most cost-efficient way, taking into account economic and social objectives and constraints. Ecologists and nature organisations often start from an techno-ecocentric paradigm: ‘How to conserve and manage species and habitats?’, in order to tackle the question mentioned above. The paradigm starts from the opinion that ‘diversity of species and habitats’ is important as such (while this is believed to be important for several reasons). This approach has been criticised lately for being based on a too narrow set of values. It has not provided enough opportunities for combining nature conservation with other forms of land use such as agriculture, forestry or tourism. In several countries this led to difficulties as regards the co-operation of local stakeholders (Jongman & Kristiansen, 1998). On the other hand, the current biodiversity crisis is a direct result of the way in which society has chosen to interact with its Natural environment. If the causes of the problem are social, it stands to reason that the policies striving to solve the problem will need to be based on a solid understanding of social structures and processes, if they are to have any effect. In this research project we tried to study the management of Natura 2000 sites from a ‘sustainability’ paradigm, instead of from the ecocentric paradigm. The central research question is therefore formulated as ‘How to manage Natura 2000 properly, to contribute to a (local) sustainable society?’ With this research we hope to give decision-makers new insights on the economic, social, and environmental consequences of Natura 2000 management and to guide them in the development of more adequate and sustainable policies for the management of Natura 2000-sites. In the first chapter the general objectives and approach of this project are described. The second chapter gives an overview of some of the current bottlenecks for nature conservation and Natura 2000. The results of the research on the elaboration of strategies for Natura 2000 sites are summarizes in chapter tree. Conclusions and recommendations are presented in the last chapter. More information on the research is documented in the different appendixes. During the research, we benefited from contacts with many persons, and more especially in the scope of a Users’ Committee. Besides the representatives of the Belgian Science Policy, we would like to thank all members of the Users’ Committee, among which those who supported us and/or participated in one or several of the meetings, [less ▲]Detailed reference viewed: 80 (2 ULg)
How to manage an isolated elevated PTH?
; CAVALIER, Etienne ;
in Annales d'Endocrinologie (2015), 76(2), 134-141
The aim of this article is to discuss the diagnostic approach of an increased serum PTH concentration in a normocalcemic, normophosphatemicpatient. Detection of this biological presentation is frequent in ... [more ▼]
The aim of this article is to discuss the diagnostic approach of an increased serum PTH concentration in a normocalcemic, normophosphatemicpatient. Detection of this biological presentation is frequent in routine practice all the more that PTH reference values established in vitamin Dreplete subjects with a normal renal function are used by the clinical laboratories. The first step in this diagnostic approach will be to rule out acause of secondary hyperparathyroidism (SHPT). Among these, the most frequent are vitamin D deficiency, very low calcium intake, impairedrenal function, malabsorptions, drugs interfering with calcium/bone metabolism, such as lithium salts and antiresorptive osteoporosis therapies,hypercalciuria due to a renal calcium leak. If no cause of SHPT are evidenced, the diagnosis of normocalcemic primary hyperparathyroidism(PHPT) should be considered. A calcium load test is a very useful tool for this diagnosis if it shows that serum PTH is not sufficiently decreasedwhen calcemia rises frankly above the upper normal limit. In a normocalcemic patient with hypercalciuria and a high serum PTH concentration,a thiazide challenge test may help to differentiate SHPT due to a renal calcium leak from normocalcemic PHPT. Beyond the discussion of thisdiagnostic [less ▲]Detailed reference viewed: 23 (4 ULg)
How to manage recurrent orofacial herpes simplex virus-1 lesions
; ; et al
in Pharmaceutical Journal (2009)Detailed reference viewed: 61 (3 ULg)
How to measure accurately blood pressure in hemodialysis patients?
VANDERWECKENE, Pauline ; SAINT-REMY, Annie ; KRZESINSKI, Jean-Marie
Conference (2016, October 29)
Objective : Blood pressure (BP) control in chronic hemodialysis (HD) patients is a major challenge and could explain the controversial results about its cardiovascular risk. Our study aimed to assess the ... [more ▼]
Objective : Blood pressure (BP) control in chronic hemodialysis (HD) patients is a major challenge and could explain the controversial results about its cardiovascular risk. Our study aimed to assess the contribution of two ambulatory techniques of measurements compared with office BP (OBP): ambulatory monitoring during a maximum of 44h interdialytic period (ABPM) and home blood pressure (HBPM) during a variable period of days in prevalent HD patients. Methodology : 43 prevalent chronically HD patients (M=28; F=15), mean age 68.3±13 years were submitted to a 44h monitoring of BP (Spacelabs 90207) from the end of an HD session to 10 minutes before the next session, immediately followed by a 7days HBPM (Omron M6). Office BP was the mean of pre-dialysis BP or post-dialysis-BP recorded over 2 weeks (6 HD sessions). Hypertension was defined as BP equal or higher than 140/90 mmHg for pre-HD, 130/80 mmHg for post-HD, 130/80 mmHg for 44 h ABPM and 135/85 mmHg for HBPM. Results : Good correlations were noted between ABPM and HBPM for the diagnosis of hypertension in HD patients. Both ambulatory techniques give the same proportion of masked hypertension and white coat hypertension compared with OBP (25%). The best diagnostic precision was noted for the longest periods of recordings (44h for ABPM and 7days for HBPM). Shorter periods were more practical for the patients but less precise for high BP identification. HBPM was more appreciated than ABPM by the patients Conclusion : ABPM and HBPM identified a quarter of patients with a particular phenotype of hypertension not correctly classified by OBP. HBPM should be first recommended in HD (at least 1 week/month). As ABPM provides unique information for nocturnal BP, it could be proposed 1 time/year in all patients. [less ▲]Detailed reference viewed: 33 (2 ULg)