Nouveautés dans le diagnostic des allergies

Conference (2013, February 19)

La lasagne pur-sang et la société low-cost

Article for general public (2013)

Pour satisfaire des consommateurs en quête de toujours plus de pouvoir d’achat, la Commission européenne soutient des gros producteurs low-cost pour une nourriture low-cost (avec des contrôles limités ... [more ▼]

Pour satisfaire des consommateurs en quête de toujours plus de pouvoir d’achat, la Commission européenne soutient des gros producteurs low-cost pour une nourriture low-cost (avec des contrôles limités). Stop! Et vive l’agriculture locale. [less ▲]

Fluxes of the greenhouse gases (CO2, CH4 and N2O) above a short-rotation poplar plantation after conversion from agricultural land

in Agricultural and Forest Meteorology (2013), 169

The increasing demand for renewable energy may lead to the conversion of millions of hectares into bioenergy plantations with a possible substantial transitory carbon (C) loss. In this study we report on ... [more ▼]

The increasing demand for renewable energy may lead to the conversion of millions of hectares into bioenergy plantations with a possible substantial transitory carbon (C) loss. In this study we report on the greenhouse gas fluxes (CO2, CH4, and N2O) measured using eddy covariance of a short-rotation bioenergy poplar plantation converted from agricultural fields. During the first six months after the establishment of the plantation (June–December 2010) there were substantial CO2, CH4, and N2O emissions (a total of 5.36 ± 0.52 Mg CO2eq ha−1 in terms of CO2 equivalents). Nitrous oxide loss mostly occurred during a week-long peak emission after an unusually large rainfall. This week-long N2O emission represented 52% of the entire N2O loss during one and an half years of measurements. As most of the N2O loss occurred in just this week-long period, accurately capturing these emission events are critical to accurate estimates of the GHG balance of bioenergy. While initial establishment (June–December 2010) of the plantation resulted in a net CO2 loss into the atmosphere (2.76 ± 0.16 Mg CO2eq ha−1), in the second year (2011) there was substantial net CO2 uptake (−3.51 ± 0.56 Mg CO2eq ha−1). During the entire measurement period, CH4 was a source to the atmosphere (0.63 ± 0.05 Mg CO2eq ha−1 in 2010, and 0.49 ± 0.05 Mg CO2eq ha−1 in 2011), and was controlled by water table depth. Importantly, over the entire measurement period, the sum of the CH4 and N2O losses was much higher (3.51 ± 0.52 Mg CO2eq ha−1) than the net CO2 uptake (−0.76 ± 0.58 Mg CO2eq ha−1). As water vailability was an important control on the GHG emission of the plantation, expected climate change and altered rainfall pattern could increase the negative environmental impacts of bioenergy. [less ▲]

Creative Spatializations: New Cartographies in Contemporary Black Canadian Fiction

Doctoral thesis (2013)

My dissertation explores the ways in which contemporary black Canadian novels rewrite national space by integrating into it what might be called past and present black spatialities. Regardless of its ... [more ▼]

My dissertation explores the ways in which contemporary black Canadian novels rewrite national space by integrating into it what might be called past and present black spatialities. Regardless of its official policy of multiculturalism, Canada appears unable to reflect the diversity of its population, one of the most multi-ethnic in the world, which results in the social and spatial exclusion of minorities—whose presence is perpetually construed as ‘recent’—from the dominant national narratives. Starting from Henri Lefebvre’s assertion that “[a] social transformation, to be truly revolutionary in character, must manifest a creative capacity in its effects on daily life, on language and on space” (54), and from the conceptualization of fictional literature as both a product and a producer of geographical creativities, this work considers the literary respatializations of black Canada in five recent novels, At the Full and Change of the Moon (1999) and What We All Long For (2005) by Dionne Brand, Any Known Blood (1997) and The Book of Negroes (2007) by Lawrence Hill, and Soucouyant (2007) by David Chariandy. I specifically examine four topographies through which these writers relate ‘blackness’ to ‘Canadianness,’ namely, the ocean, the city, the rural suburb, and the home space. More specifically, this dissertation illuminates how these literary representations of Canadian space locate this nation within the paradigmatic locations of black history but also show how the country’s social and geographical landscape is marked by the black history that took place in the country itself. Through a multidisciplinary approach which looks at theorizations of space emanating from literary, geographical, and sociological fields of study, I examine how these writers shift the terms of Canadian identity by disrupting the founding narratives of the nation which rely on the country’s wild landscapes and construct Canada as a white-only space. Finally, this dissertation engages with racialized bodies whose interconnectedness with both physical and imaginary spaces allow for a multiplicity of creative spatializations to emerge. [less ▲]

A cross-sectional study to assess knowledge about HIV/AIDS transmission and prevention measures in company workers in Ecuador

in BMC Public Health (2013), 13

Background: HIV/AIDS was first reported in Ecuador in 1984 and its prevalence has been increasing ever since. In 2009, the National AIDS Program reported 21,810 HIV/AIDS cases and confirmed that the ... [more ▼]

Background: HIV/AIDS was first reported in Ecuador in 1984 and its prevalence has been increasing ever since. In 2009, the National AIDS Program reported 21,810 HIV/AIDS cases and confirmed that the worker population was amongst the most affected groups. The objective of this study was to assess knowledge about HIV transmission and prevention measures in company workers in Ecuador. Methods: A cross-sectional survey based on a random sample of 115 companies (1,732 workers), stratified by three large provinces and working sectors (commerce, manufacturing and real estate) was conducted. A validated instrument developed by Family Health International was used to evaluate HIV prevention knowledge and common local misconceptions about HIV transmission. Descriptive statistics, chi square test and logistic regression analysis were performed using SAS. Results: Incorrect knowledge about HIV/AIDS transmission were found in 49.1% (95% CI: 46.6-51.6) of subjects. Incorrect knowledge was higher among males (OR=1.73 [1.39 –2.15]), older subjects (OR=1.35 [1.02 – 1.77]), subjects with lower education (OR=3.72 [2.44 – 5.65]), manual labor workers (OR=2.93 [1.82 – 4.73]) and subjects without previous exposure to HIV intervention programs (OR=2.26 [1.79 – 2.86]). Incorrect knowledge about preventive measures was found among 32.9% (95%CI: 30.6-35.2) of respondents. This proportion was higher among subjects with lower education (OR=2.28 [1.52 – 3.43]), married subjects (OR=1.34 [1.07 – 1.68]), manual labor workers (OR=1.80 [1.34 – 2.42]), and subjects not previously exposed to HIV intervention programs (OR=1.44 [1.14 – 1.83]). Conclusions: HIV intervention programs targeting company workers are urgently needed to improve knowledge and reduce HIV transmission in Ecuador. [less ▲]

Random generation of dichotomous CAT response patterns with the R package catR

Conference (2013, February 14)

The purpose of this talk is to briefly introduce the R package catR that permits random generation of response patterns under a computerized adaptive testing (CAT) framework. First, an outline of the CAT ... [more ▼]

The purpose of this talk is to briefly introduce the R package catR that permits random generation of response patterns under a computerized adaptive testing (CAT) framework. First, an outline of the CAT is proposed, with emphasis on the main concepts (item bank, ability estimation, next item selection, stopping rule, item exposure and content balancing). Then, the performance of the catR package is described by making connections between the general CAT framework and the functionalities of the R functions within catR. An example will be displayed, either as a “live” demonstration of catR or as part of the talk. Potential extensions of catR will also be discussed. The catR package was jointly developed by Gilles Raîche (Université du Québec à Montréal, Canada). [less ▲]

Kidney and Pancreas Transplantation : The history of Surgical Techniques and immunosuppression

in current issues and future direction in kidney transplantation (2013)

Pancreas Transplantation aims at providing Beta cells replacement in diabetic patients, especially for type 1 diabetes recipients in whom Beta cells had been destroyed by an autoimmune process. The final ... [more ▼]

Pancreas Transplantation aims at providing Beta cells replacement in diabetic patients, especially for type 1 diabetes recipients in whom Beta cells had been destroyed by an autoimmune process. The final achievement is to restore a normal physiological control of glucose metabolism in order to halt or reverse the secondary complications of diabetes i.e. retinopathy, neuropathy, nephropathy, micro – and macro - angiopathy [1]. That can be achieved by a vascularised pancreas graft (referred as Pancreas Transplantation, PT) or by islet grafting (referred as Islet Transplantation, IT). The former PT includes transplanting 95% of unuseful cells, the exocrine part from one pancreas, while the last one IP, embolizing into the recipient liver, Islets of Langerhans after digestion and purification of several human pancreases. Three types of PT can be performed: the pancreas and a kidney are simultaneously transplanted with a single induction of immunosuppression (IS) therapy in hoping to correct both uremia and diabetes mellitus (SPK = Simultaneous Pancreas and Kidney Transplantation); the pancreas is transplanted after a successful kidney graft allowing two induction therapies along with the basic IS treatment (PAK = Pancreas After Kidney Transplantation) ; and finally the Pancreas can be transplanted alone in pre-uremic recipients with unawareness hypoglycaemic events or with rapidly evolving secondary complications of diabetes such as proliferative retinopathy, or advanced neuropathy (PTA = Pancreas Transplantation Alone) [1]. Moreover, in SPK, both organs the Pancreas and the Kidney are procured from the same deceased donor, either donor after brain death (DBD) or donor after cardiac death (DCD). In some US institutions, a segmental pancreas and the left kidney, are procured in a living donor [2], using a laparoscopic approach in the more recent year [3]. For PAK, in order to avoid an excessive IS load and two induction therapies, other institutions had proposed whenever possible to keep in stand-by the potential live kidney donor until a cadaver whole pancreatic compatible graft is available [1]. By contrast, the number of PTA remains limited in non uremic recipients with life-threatening complications of diabetes, in whom one might hope to avoid the hypoglycaemic events with a successful graft. That can also be achieved with IT. But except for rare cases, insulin independence with IT requires more than a single human pancreas and is limited over time [1]. Moreover, IT needs costly materials, chambers and rooms for preparation. That’s why IT will not be included in the present report. [less ▲]

Considérations sur quelques visions mystiques à l'abbaye Saint-Laurent de Liège

Conference given outside the academic context (2013)

Cette conférence entendait exposer les raisons de l'auteur de privilégier la thèse d'un foyer bénédictin rhéno-mosan de visionnaires de la Trinité au XIIe siècle, à l'appui de considérations d'ordre ... [more ▼]

Cette conférence entendait exposer les raisons de l'auteur de privilégier la thèse d'un foyer bénédictin rhéno-mosan de visionnaires de la Trinité au XIIe siècle, à l'appui de considérations d'ordre historique, liturgique, théologique et iconographique. [less ▲]

An overview of statistical methods to assess differential item functioning and differential test functioning

Scientific conference (2013, February 12)

This talk broadly focuses on the identification of differential item functioning (DIF) and differential test functioning (DTF). After a short introduction of the key concepts, most-known methods to detect ... [more ▼]

This talk broadly focuses on the identification of differential item functioning (DIF) and differential test functioning (DTF). After a short introduction of the key concepts, most-known methods to detect DIF and DTF with dichotomously or polytomously scored items, and between two or more than two groups, are presented. Both parametric (i.e. IRT) and nonparametric (i.e. score-based) methods are described in a non-technical way. Several potential applications to PISA surveys are discussed. [less ▲]

Trimming the complexity of Ranking by Pairwise Comparison

Doctoral thesis (2013)

In computer science research, and more specifically in bioinformatics, the size of databases never stops to increase. This can be an issue when trying to answer questions that imply algorithms in ... [more ▼]

In computer science research, and more specifically in bioinformatics, the size of databases never stops to increase. This can be an issue when trying to answer questions that imply algorithms in nonlinear polynomial time with regards to the number of objects in the database, the number of attributes or the number of associated labels per objects. This is the case of the Ranking by Pairwise Comparison (RPC) algorithm. This algorithm builds a model which is able to predict the label preference for a given object, but the computation needs to be performed in an order of N*(N-1)/2 in terms of the number N of labels. Indeed, a pairwise comparator model is needed for each possible pair of labels. Our hypothesis is that a significant part of the set of comparators often contains redundancy and/or noise, so that trimming the set could be beneficiary. We implemented several methods, starting from the simplest one, which merely chooses a set of T comparators (T < N*(N-1)/2) at random, to a more complex approach based on partially randomized greedy search. This thesis will provide a detailed overview of the context we are working in, provide the reader with required background, describe existing preference learning algorithms including RPC, investigate on possible trimming methods and their accuracy, then will conclude on the relevance and robustness of the trimming approximation. After implementing and executing the procedure, we could see that using between N/2 and 2N comparators was sufficient to keep up with the original RPC algorithm, as long as a smart trimming method is used, and sometimes even outperforms it on noisy datasets. Also, comparing the use of base models in regression mode vs. classification mode showed that models built in regression mode may be more robust when using the original RPC. We thus empirically show that, in the particular case of RPC, reducing the complexity of the method gives similar or better results, which means that problems that could not be addressed by this algorithm, or at least not in an acceptable period of time, now can be. We also found that the regression mode yields RPC to be often more robust regarding its base learner parameters, meaning that the quest of optimality, which can also be time-consuming, is less difficult. Yet research on this topic is not over, and we could think of different means to further improve the RPC algorithm or investigate other innovative approaches, which will be discussed in the future work section. Also, the trimming method is not limited to RPC and could be applied to other algorithms which aggregate information provided by a set of models, e.g. the whole multitude of ensemble models used in machine learning. [less ▲]