Decorating a domus during the second triumvirate. Iconographical program of the Dwarfs’ oecus at Ostia Antica.

Conference (2013, September)

A small overview of available computer software to support computerized adaptive testing

Conference (2013, August 27)

Computerized adaptive testing (CAT) is becoming a central tool for testing and assessment. It offers many advantages over fixed (“paper-and-pencil”) methods, such as individualized assessment, reduction ... [more ▼]

Computerized adaptive testing (CAT) is becoming a central tool for testing and assessment. It offers many advantages over fixed (“paper-and-pencil”) methods, such as individualized assessment, reduction of fraud, and straightforward estimation of proficiency levels. CAT has been studied for decades and remains an up-to-date research field in psychometrics and educational science. Practical CAT administration, however, is less frequently considered in such studies. Assigning CAT to respondents requires both the sufficient availability of computer machines, and the use of a powerful and easy-to-use CAT software. With the fast increase of computer resources at moderate cost, the availability of computer machines is becoming a less central, yet important, issue in the practical assessment of CAT tests. The choice of an accurate CAT software, on the other hand, should be guided by its flexibility, its underlying statistical modeling, and its user-friendly potential. According to the type of research or data analysis, some CAT software might be preferred to another. It is therefore important for the researcher or the clinician to know about the current availability of such software, in line with current research and practice in the CAT framework. Moreover, these software should allow enough flexibility to incorporate updates and new theoretical developments, such as e.g., new rules for next item selection. This talk proposes a simple and user-oriented presentation of several CAT software that are currently available. The software to be presented are: the Firestar software (Choi, 2009), the R package catR (Magis & Raîche, 2012), the R package catIrt (Nydick, 2012) and the CAT web-platform Concerto (Kosinski & Rust, 2011). The first three are non-commercial software, while Concerto is a web interface between end users (willing to develop computerized assessment tests) and catR (as underlying routine software). Both R packages are written to be most useful for researchers, without end-user interface, and are therefore less appealing for applied researchers who are not familiar with R. Yet, they offer flexible solutions by means of many options to optimize the design of the test and generate many response patterns for further analyses. Also, they can be easily integrated as sub-routines for more sophisticated CAT software. Firestar provides a user interface and makes all necessary computations with underlying R code. This talk aims at focusing on freely available CAT software. For this reason, only the four aforementioned programs will be presented, although it exists other, commercial CAT software such as e.g., the CATSim software (Assessment Systems Corporation, 2012). The different CAT software are briefly presented and their advantages and drawbacks, flexibility and usefulness are compared, mostly from the point of view of the applied researcher and clinician. The following criteria were retained for objective comparison: (a) their main goal of application; (b) the type of data and IRT modeling they can deal with; (c) the type of users they are focusing on; (d) their operating options; (e) their availability and flexibility for further improvements. A small demonstration of the R package catR will be proposed optionally, depending on time limitation. References Assessment Systems Corporation (2012). CATSim: Comprehensive simulation of computerized adaptive testing. St. Paul, MN. URL: http://www.assess.com/. Choi , S. W. (2009). Firestar: Computerized adaptive testing simulation program for polytomous item response theory models. Applied Psychological Measurement, 33, 644-645. Kosinski, M., & Rust, J. (2011). The development of Concerto: An open source online adaptive testing platform. Paper presented at the International Association for Computerized and Adaptive Testing (IACAT), Pacific Grove, CA. Magis, D., & Raîche, G. (2012). Random generation of response patterns under computerized adaptive testing with the R package catR. Journal of Statistical Software, 48, 1-31. Nydick, S. W. (2012). catIrt: An R package for simulating IRT-based computerized adaptive tests. R package version 0.3-0. [less ▲]

Taste analysis. How practice in an industrial and scientific context shapes sturdy sensory categories.

Conference (2013, August 08)

Sensory analysis presents the particular characteristic to be placed in a crossroad, especially when it is about taste. Sensory, which is the most of the time the space of subjective and hedonic judgments ... [more ▼]

Sensory analysis presents the particular characteristic to be placed in a crossroad, especially when it is about taste. Sensory, which is the most of the time the space of subjective and hedonic judgments, meets Science, which has the main goal to establish an objective truth, through sturdy and stable categories. I followed several types of sensory expert panels, and among them a panel who has the mission to discriminate different sorts of carrots and define their respective sensory profile. The judges were specifically teached and trained to taste and analyze carrots. I was interested to observe the period of training to understand how those people had acquired their expertness. In this presentation, I would tempt an analysis of how participants build themselves the tools and tricks to perform a best organoleptic perception, and how they go beyond the rules and formal process to answer to the forms. [less ▲]

Effects of eccentrically and concentrically biased training on mouse muscle phenotype

in Medicine & Science in Sports & Exercise (2013)

Introduction: The molecular adaptations specifically induced by different muscle contraction types have only been partially elucidated. We previously demonstrated that eccentric contractions in human ... [more ▼]

Introduction: The molecular adaptations specifically induced by different muscle contraction types have only been partially elucidated. We previously demonstrated that eccentric contractions in human quadriceps elicited proteome modifications that suggest a muscle fiber typology adaptation. We address this question in a more systematic way by examining here the effects of different running modes on the mouse muscle proteome and the muscle fiber typology. Methods: Male adult mice (C57BL6) were randomly divided into downhill running (DHR, quadricipital eccentrically biased contractions), uphill running (UHR, quadricipital concentrically biased contractions) and untrained control (CONT) groups. Running groups performed five training sessions on an inclined treadmill for 75 to 135 min/day and the quadriceps muscles were dissected 96hours after the last session. Muscle protein extracts of DHR and UHR groups (n=4/group) were subjected to a 2D-DIGE analysis coupled with mass spectrometry. The assessment of fiber type, size and number was performed on the rectus femoris of the three groups (n=6/group) using myosin heavy chain (MHC) immunohistochemistry. Results: In the proteomic analysis, eight spots identified as the fast MHC isoforms exhibited a lower abundance in DHR compared to UHR (p<0.05, t-test). In contrast, ATP synthase subunit α and tubulin β were more expressed in DHR (p<0.05). A significant higher proportion of type I and IIa fibers was found for DHR compared to UHR or CONT groups (p<0.05, one-way ANOVA). Conclusions: Our data suggest that the eccentrically biased contractions in mice induced specific adaptations in protein expression and muscle fiber composition which may reflect a more oxidative muscle phenotype. The differences in stress placed on the muscle between both trainings may be responsible for some unique adaptations resulting from the eccentrically biased training. [less ▲]

The « boring billion » : an exciting time for early eukaryotes !

Conference (2013, August)

Comparison of three NDT techniques for the inspection of aeronautic composite structures

Conference (2013, July 28)

Franz Thedieck (1900-1995): Zur Biographie eines "rationalen Propagandisten" im 20. Jahrhundert

Scientific conference (2013, July 17)

Reconstructing historical atmospheric mercury deposition in Western Europe: The case study of the ombrotrophic Misten peat bog (Belgium)

Poster (2013, July 11)

Narrateur, personnage et lecteur. Pragmatique des subjectivèmes relationnels, des points de vue énonciatifs et de leur dialogisme

in Cahiers de Narratologie (2013)

Les instances internes au récit que sont le narrateur, le personnage et le lecteur virtuel entretiennent des relations, principalement idéologiques et affectives, que l’on peut décrire d’après une ... [more ▼]

Les instances internes au récit que sont le narrateur, le personnage et le lecteur virtuel entretiennent des relations, principalement idéologiques et affectives, que l’on peut décrire d’après une approche pragma-énonciative et rhétorique. Nous proposons une modélisation du système intra-relationnel du récit et une réflexion sur plusieurs problématiques que pose l’analyse de ces relations : le repérage des subjectivèmes relationnels, l’identification de leurs effets pragmatiques, leur assemblage en un point de vue émanant d’un sujet énonciateur particulier, les différentes articulations possibles entre les points de vue du narrateur et du personnage et leurs effets pragmatiques. D’après cette perspective nous proposons une nouvelle analyse et interprétation du récit La Femme de Gilles de Madeleine Bourdouxhe. [less ▲]

Chemical imaging of small molecules from simple to complex matrices: Quantitative approches based on Surface Enhanced Raman scattering

Conference (2013, July)

Surface Enhanced Raman scattering (SERS) allows to dramatically exalt the Raman diffusion of molecules absorbed or very closed to rough metallic surfaces while keeping their structural information. SERS ... [more ▼]

Surface Enhanced Raman scattering (SERS) allows to dramatically exalt the Raman diffusion of molecules absorbed or very closed to rough metallic surfaces while keeping their structural information. SERS chemical imaging, presenting a high specificity and sensibility, allows acquiring a visual representation of samples combining spectral and spatial measurements. This technique could become a powerful tool in pharmaceutical and biological analysis enabling to identify and quantify molecules thanks to chemometric evaluation while looking at their distribution or their interactions. In this context, SERS chemical imaging is investigated in detection or quantitative determination of molecules in pharmaceutical and biological matrices. The feasibility of making quantitative measurements using SERS is evaluated on small target molecules models such as 4-aminophenol and lactate. Firstly, a SERS method to quantify 4-aminophenol which is the primary impurity of acetaminophen coming from its degradation during the storage or from its synthesis was developed on a real pharmaceutical formulation. The standard addition method was selected as calibration method in order to take into account the matrix effect coming from the different components of the latter. Despite the well-known stability and repeatability problems of SERS, the method was thoroughly validated by means of accuracy profiles as decision tool. Moreover, this validation methodology allowed to define a first estimation of the real analytical performance of the technique. Secondly, the detection of lactate, which is a critical metabolite implicated in several metabolic disorders, was successfully tested in the physiological concentration in a simple matrix. Preliminary results for the determination of this metabolic biomarker were also very promising allowing to consider more complex matrices. Based on these results, SERS chemical imaging was implemented to detect 4-aminophenol in a pharmaceutical tablet formerly pulverised by a SERS substrate. Through this imaging technique, it was not only possible to detect the presence of the impurity at the limit of specification of 0.1% (w/w) but it was also possible to differentiate tablets comprising different concentrations of the latter. These promising results represent the first step towards quantitative measurements using SERS chemical imaging. [less ▲]