Quasi-One-Dimensional Numerical Simulations of Post-Stall Compression Systems

Doctoral thesis (2013)

Hygrothermal behavior modeling of different Lime-Hemp Concrete mixes

Conference (2013, May 27)

This paper studies the specific hygrothermal behavior of Lime-Hemp concretes through analysis of non-linear coupled heat and moisture transfer using a research model. Three compositions were studied ... [more ▼]

This paper studies the specific hygrothermal behavior of Lime-Hemp concretes through analysis of non-linear coupled heat and moisture transfer using a research model. Three compositions were studied, varying the type of binder. First Moisture Buffer Value determination tests are lead experimentally using the NORDTEST protocol. These dynamic experiments, which reveal the moisture storage and exchange capacity together with latent heat effects, are then modeled using a set of partial differential equations. The reduction of humidity buffering capacity induced by hydraulic binder incorporation is properly evaluated and the hygrothermal parameters can be assessed by inverse modeling. [less ▲]

Blattmaske. Figure du rinceau peuplé dans les mosaïques d'Asie Mineure

Scientific conference (2013, May 25)

Expliquer et illustrer Prospéro. Suivre le marqueur temporel "le-pire-est-à-venir" au sein des agendas politiques climatiques belges (1980-2012)

Conference (2013, May 24)

Variabilité de la respiration hétérotrophe du sol dans des écosystèmes agricoles: Analyse à différentes échelles spatiales et temporelles.

Doctoral thesis (2013)

Soil heterotrophic respiration (HR) was studied at different spatial and temporal scales in agricultural ecosystems in Belgium (loamy region). Results from both laboratory and field experiments conducted ... [more ▼]

Soil heterotrophic respiration (HR) was studied at different spatial and temporal scales in agricultural ecosystems in Belgium (loamy region). Results from both laboratory and field experiments conducted at short and long timescales were analysed with the aim to better understand the influence of driving variables such as temperature, substrate input quantity and quality on HR. Both empirical and semi-mechanistic models were used in order to help interpret experimental results. Our observations showed that temperature is an important HR driving variable in agricultural ecosystems in temperate regions. HR sensitivity to temperature, characterized by a Q10 differing from 2 in our experiments, was very likely influenced by substrate availability and quality. The impact of these last two factors was however never observed through our measurements. Good agreement between modelled and observed CO2 fluxes in the incubation experiment, where carbon substrate was limited, suggested that temperature played a role both directly (enzymatic response) and indirectly (labile carbon stock depletion) at a relatively short term, and confirmed the hypothesis of occurrence of abiotic fluxes linked to the presence of carbonates in the samples taken from a limed agricultural field. Crop residue management (in both quantity and quality), as characterized by relatively low input levels in our experiment, influenced soil carbon stocks in the long term. However, HR, microbial biomass, labile carbon and metabolic diversity were not affected by the investigated treatments. Besides, results from both soil carbon budgets and short term HR measurements showed that supposedly large differences were likely to be reduced due to the relatively large proportion of root residues, weeds and residues unexported at harvest. [less ▲]

Introduction

Conference (2013, May 23)

A BAYESIAN PROBABILITY CRITERION TO ASSESS ANALYTICAL RESULTS RELIABILITY

Conference (2013, May 21)

In pharmaceutical and biomedical industries, quantitative analytical methods such as HPLC play a key role. Indeed, the analytical results obtained from them are used to make crucial decisions such as the ... [more ▼]

In pharmaceutical and biomedical industries, quantitative analytical methods such as HPLC play a key role. Indeed, the analytical results obtained from them are used to make crucial decisions such as the release of batches of drugs, the evaluation of safety and efficacy of new drug candidates or the monitoring of patients health. Prior to their routine use, analytical methods are submitted to a stringent validation study [1] where they have to demonstrate that they are fit for their final purpose, i.e. providing accurate results: where is the analytical result, is the theoretical unknown true concentration of analyte in the sample analyzed and a regulatory acceptance limit. Typically this demonstration is made by either providing point estimates of systematic error (bias) and random error (variance) or sometimes by providing interval estimates of these statistical parameters at several well defined concentration levels of the target analyte [2]. They are then compared to maximum acceptable levels. More recently, tolerance intervals approaches have been proposed that are evaluated in a similar way at these key concentration levels [3]. However none of these decision approaches allow knowing the probability to obtain accurate results over the whole concentration range of interest: is a vector of parameters and Pmin is a minimum reliability probability. Frequentist approximations have been proposed to estimate this probability but only at the concentration levels experimentally tested [4,5]. In this work, a linear hierarchical Bayesian approach is proposed. It takes into account the potential random characteristic of the slope and intercept observed from one analytical run to the other, but it also integrates the possible covariance between the parameters. Additionally, heteroscedasticity of the residual variance over the concentration range investigated is taken into account. A situation regularly observed in practice. Finally a reliability profile for the whole concentration range studied is obtained using MCMC sampling. This profile provides the probability (Prel) to obtain accurate results over the full concentration range investigated. This profile is then compared to a minimum reliability probability (Pmin) that will define the valid concentration range of the analytical method. The usefulness of this approach is illustrated through the validation of a bioanalytical method and also compared with one concentration level at a time frequentist approaches [4,5]. [1] International Conference on Harmonization (ICH) of Technical Requirements for registration of Pharmaceuticals for Human Use Topic Q2 (R1): Validation of Analytical Procedures: Text and Methodology, Geneva, 2005. [2] A. Bouabidi and al., J. Chromatogr. A, 1217 (2010) 3180. [3] Ph. Hubert and al., J. Pharm. Biomed. Anal., 36 (2004) 579. [4] W. Dewé and al., Chemometr. Intell. Lab. Syst. 85 (2007) 262. [5] B. Govaerts and al., Qual. Reliab. Engng. Int. 24 (2008) 667. [less ▲]

Travaux en cours sur la présence isiaque dans le Péloponnèse : les lieux de culte

Scientific conference (2013, May 18)

La structuration du monde paysan au Rwanda : cas des coopératives et des stations de lavage de café de Maraba et de Karaba, District de Huye

Doctoral thesis (2013)

The agricultural sector is the main economic activity of Rwanda, which occupies approximately 90% of the active population in rural areas. It contributes more than 36% to the GDP. Coffee is the main cash ... [more ▼]

The agricultural sector is the main economic activity of Rwanda, which occupies approximately 90% of the active population in rural areas. It contributes more than 36% to the GDP. Coffee is the main cash crop and source of income for farmers, and provides major currencies for the national economy. Although it covers only 6.3% of cultivated areas, coffee is produced by 500,000 households in Rwanda. Since its introduction in the country in 1904, coffee has always been operated by individual producers. After the liberalization of the coffee sector in Rwanda in 1998, the quantity and quality produced are steadily decreasing which affects the price and the income of coffee growers. In the search for a solution to this problem, the Rwandan government has focused on the consolidation of producers cooperatives, and on the building of coffee washing stations (CWS) in all coffee growing areas at national level. The goal is to produce a fully washed coffee, exportable and better valued on the international market, which can provide better income for peasant producers. Washing stations are then seen as tools to produce quality coffee and are mainly run by cooperatives, which are structural elements in the rural world. Survey work on a sample of 80 farms for the three seasons (2008, 2009, 2010) as well as interviews with various key agents involved in the coffee sector have been conducted to understand and analyze the effects of CWS and cooperatives on coffee growers. This original dissertation is devoted to analyze the impact resulting from the structure action of the peasant world through cooperatives and coffee washing stations of Maraba and Karaba in southern Rwanda, on the socio-economic development of farmers who are members of a cooperative and the surrounding world by comparing to non-members of cooperatives. Through these facilities and structures put in place, jobs are created for producers, farmers are motivated due to income increases, the market is guaranteed, the prices are higher for members and loans are given, thereby improving the socio-economic and technical assistance to growers, which reduces the poverty among coffee growers’ households. [less ▲]

Inceste et Famille: confrontation et complémentarité des notions structuralistes et de pertes ambiguës dans la prise en charge systémique (atelier)

Conference (2013, May 17)

Dans le travail avec les familles connaissant une situation d’inceste, le paradigme structura liste de Minuchin (1974) apparaît souvent comme l’angle d’approche systémique privilégié. Bien qu’initialement ... [more ▼]

Dans le travail avec les familles connaissant une situation d’inceste, le paradigme structura liste de Minuchin (1974) apparaît souvent comme l’angle d’approche systémique privilégié. Bien qu’initialement celui-ci ne s’adresse pas spécifiquement aux situations de maltraitances infantiles et plus particulièrement d’inceste, nous proposons d’illustrer, au travers du cheminement d’une vignette clinique, combien un tel regard permet la mise en lumière du fonctionnement familial et, dans le respect de l’éthique systémique, de dessiner les pistes thérapeutiques par le biais même de la démarche diagnostique. notre pratique clinique dans une équipe spécialisée nous montre cependant que le travail avec la famille connaissant une situation d’inceste ne peut se résumer à mieux comprendre le passé pour préparer l’avenir. en effet, bien souvent, ces familles connaissent une situation qui, selon nous, s’apparente à ce que pauline Boss (1999, 2006) a nommé la perte ambiguë. après un exposé théorique des notions de pertes et de frontières ambiguës (Boss, 1999, 2006) auxquelles il est très certainement moins fréquent de faire appel dans la prise en charge (systémique) de l’inceste, nous montrerons au travers l’exploration de la même vignette clinique pourquoi et comment ce cadre conceptuel a toute sa pertinence dans le travail clinique. enfin, après avoir démontré l’utilité, la complémentarité et les différences entre l’approche de Minuchin et celle de Boss, nous pourrons nous tourner vers les questions soulevées par notre exposé. en effet, dans les situations d’inceste et d’agression sexuelle en général, l’étude des mécanismes à l’œuvre, tant du point de vue individuel que systémique, a permis et permet de mieux comprendre les facteurs impliqués et dès lors de prévenir et soigner. toutefois, s’il est bien naturel que les projecteurs se tournent vers la transgression des interdits sexuels, il n’en reste pas moins que la famille se trouve confrontée, dans l’ici et maintenant, à une inéluctable réorganisation. les difficultés inhérentes à celle-ci, si elles ne sont pas prises en compte, pourraient amener à ne pas permettre l’expression des compétences familiales (ausloos, 1995) au moment où leur évaluation est pourtant requise, et à offrir aux familles un soutien davantage adapté à leur histoire qu’à leur actualité. [less ▲]