L'éducation à la paix dans l'enseignement primaire belge de l'entre-deux-guerres : entre apaisement et stigmatisation

Conference (2013, May 24)

Individual needs in flexibility and employment security: a qualitative approach

Conference (2013, May 24)

Introduction

Conference (2013, May 23)

Influence of dipole-dipole interactions on the superradiant pulse

Poster (2013, May 23)

Superradiance, known as the cooperative spontaneous emission of a directional light pulse by excited atoms placed in vacuum, has recently regained attention in the context of photon localization [1] and ... [more ▼]

Superradiance, known as the cooperative spontaneous emission of a directional light pulse by excited atoms placed in vacuum, has recently regained attention in the context of photon localization [1] and single photon cooperative emission [2]. The dissipative dynamics of the atoms is known to depend dramatically on the ratio between the typical inter-atomic distance and the atomic transition wavelength, notably because of dipole-dipole interactions [3]. In this work, we study the effects of these interactions on superradiance as in [4] by solving numerically the corresponding master equation. In particular, by averaging over many realizations of the randomly distributed atomic positions, we show that the decay of the radiated energy pulse height with the intensity of the dipolar coupling follows a power law. [1] E. Ackermans, A. Gero & R. Kaiser, Phys. Rev. Lett. 101, 103602 (2008). [2] R. Friedberg & J. T. Manassah, J. Phys. B 43, 035501 (2010). [3] M. Gross & S. Haroche, Physics reports 93, 301-396 (1982). [4] B. Coffey & R. Friedberg, Phys. Rev. A 17, 1033 (1978). [less ▲]

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 ▲]

Emotion, mort et conscience. Le premier Sartre et la psychanalyse

Conference (2013, May 16)

Dust historical record in ombrotrophic peat: The case study of a NW European bog

Poster (2013, May 16)

Ombrotrophic peatlands are unique environmental archives of natural and anthropogenic atmospheric dust deposition because their surface layers are exclusively fed by atmospheric inputs. Lead (Pb) isotopes ... [more ▼]

Ombrotrophic peatlands are unique environmental archives of natural and anthropogenic atmospheric dust deposition because their surface layers are exclusively fed by atmospheric inputs. Lead (Pb) isotopes have been often used to evidence any anthropogenic influence in peat, but they only record trace metal pollution. Another radiogenic isotope, the Neodymium (Nd), could be also use to discriminate the sources of dust in peat bogs. Dust fluxes were investigated over the last 2500 years in the Misten peat bog in Eastern Belgium. Our aims were to use Nd isotope signature to decipher between local and distal dust supplies, the Pb isotopes to trace the antropogenic influences. To address these aims we analyzed REE and lithogenic element analyses, as well as the Nd and Pb isotopes, using HR-ICP-MS and MC-ICP-MS, respectively in peat layers dated by 210Pb and 14C. Changes in REE concentration variations in peat samples are correlated with Ti, Al, and Zr that are lithogenic conservative elements, suggesting that REE are immobile in the studied peat bogs and can be used as tracers of dust deposition. Dust fluxes show pronounced increase at BC300, AD600, 1000AD, 1200AD and from 1700AD, recording either influence of human activities (regional erosion due to forest clearing and soil cultivation activities) or local and regional climate changes. Lead enrichments reveal strong human impact over the last 300 years. Lead isotope signatures are consistent with local and regional contamination by coal combustion and smelting activities. Neodymium isotopes allow to identify three periods characterised by dominant-distal sources (at 320AD, 1000 AD and 1700AD). Those periods are consistent with local wetter intervals as indicated by lower humification degree. Local erosion prevails durier drier (higher humification) intervals (-100AD, 600AD). On a global scale more distal supplies are driven during colder periods, in particular Oort and Maunder minima, confirming the hypothesis that cold climate conditions favor distal supplies. Combining geochemical elementary content and isotope data in ombrotrophic peat allows to decipher between dust flux changes related to human and climate forcing. [less ▲]