Statistical study on the link between real energy use, official energy performance and inhabitants of low energy houses

Energy performance regulations are becoming increasingly strict and governments supply simplified calculation tools to assess whether new buildings fulfil the requirements. However, one can wonder what the accuracy of those tools is for assessing the next generation of houses, that will have to fulfil the upcoming energy requirements. In order to investigate the discrepancy between predicted and real energy use in low energy houses, 537 dwellings were analysed. Data on building characteristics and theoretical energy use from the Flemish EPBD-database was complemented with data from the energy utilities and a survey of the inhabiting households, providing information about the households, their user behaviour and real energy use. While an undeniable correlation was found between theoretical and real energy use, the EPBD-method overestimated the heating energy use for most of the cases. Two building related parameters and two user related parameters proved to have a significant impact on that gap: the use of default values for the air tightness of the envelop and for the efficiency of the gas boiler, the heating profiles of the master bedrooms and the amount of baths and showers taken by the inhabitants. However, two comments must be made. First, the dataset consists of early adopters who could afford such energy performance years before it would be imposed and are therefore not representative of the average household. In addition, the analysis showed significant correlations between household characteristics on the one hand and building characteristics and performance on the other. These last two points question the possibility to extrapolate findings from samples of existing forerunners towards prognoses on future, entire building stock level

Evolution of energy performance of houses and the interaction with energy performance regulation: an analysis of the Flemish EPBD-database

Energy performance regulations for buildings are continuously updated. Projections within the future are being made, fixing now what will be the standards for new buildings for the following decades. The construction sector itself is also evolving, trying not only to follow those new rules, but often trying to look ahead, developing, testing and launching today the prototypes of tomorrow’s buildings and components. To optimise public and private decision making, one has to analyse both the current status as well as the ongoing evolutions and the interactions between the market and the regulatory framework. Within this scope, analyses are conducted in Flanders on the EPBD-database, which contains detailed data on all new residential buildings since 2006. The analysis presented in this paper shows the impact and importance of specific regulations and incentives. In spite of the tightening regulations, huge discrepancies remain visible between a small yet increasing group of low energy, and passive house ‘pioneers’ and premium hunters, as opposed to a trailing group, flirting with the legally imposed limits. The analysis of the data therefore proves the role of as well as some challenges for future decision making, while quantifying the real status and evolutions of the building sector

AURORA : bariatric surgery registration in women of reproductive age : a multicenter prospective cohort study

Background: The expansion of the obesity epidemic is accompanied with an increase in bariatric procedures, in particular in women of reproductive age. The weight loss induced by the surgery is believed to reverse the negative impact of overweight and obesity on female reproduction, however, research is limited to in particular retrospective cohort studies and a growing number of small case-series and case-(control) studies. Methods/design: AURORA is a multicenter prospective cohort study. The main objective is to collect long-term data on reproductive outcomes before and after bariatric surgery and in a subsequent pregnancy. Women aged 18-45 years are invited to participate at 4 possible inclusion moments: 1) before surgery, 2) after surgery, 3) before 15 weeks of pregnancy and 4) in the immediate postpartum period (day 3-4). Depending on the time of inclusion, data are collected before surgery (T1), 3 weeks and 3, 6, 12 or x months after surgery (T2-T5) and during the first, second and third trimester of pregnancy (T6-T8), at delivery (T9) and 6 weeks and 6 months after delivery (T10-T11). Online questionnaires are send on the different measuring moments. Data are collected on contraception, menstrual cycle, sexuality, intention of becoming pregnant, diet, physical activity, lifestyle, psycho-social characteristics and dietary supplement intake. Fasting blood samples determine levels of vitamin A, D, E, K, B-1, B-12 and folate, albumin, total protein, coagulation parameters, magnesium, calcium, zinc and glucose. Participants are weighted every measuring moment. Fetal ultrasounds and pregnancy course and complications are reported every trimester of pregnancy. Breastfeeding is recorded and breast milk composition in the postpartum period is studied. Discussion: AURORA is a multicenter prospective cohort study extensively monitoring women before undergoing bariatric surgery until a subsequent pregnancy and postpartum period

The genomic landscape of balanced cytogenetic abnormalities associated with human congenital anomalies

Despite the clinical significance of balanced chromosomal abnormalities (BCAs), their characterization has largely been restricted to cytogenetic resolution. We explored the landscape of BCAs at nucleotide resolution in 273 subjects with a spectrum of congenital anomalies. Whole-genome sequencing revised 93% of karyotypes and demonstrated complexity that was cryptic to karyotyping in 21% of BCAs, highlighting the limitations of conventional cytogenetic approaches. At least 33.9% of BCAs resulted in gene disruption that likely contributed to the developmental phenotype, 5.2% were associated with pathogenic genomic imbalances, and 7.3% disrupted topologically associated domains (TADs) encompassing known syndromic loci. Remarkably, BCA breakpoints in eight subjects altered a single TAD encompassing MEF2C, a known driver of 5q14.3 microdeletion syndrome, resulting in decreased MEF2C expression. We propose that sequence-level resolution dramatically improves prediction of clinical outcomes for balanced rearrangements and provides insight into new pathogenic mechanisms, such as altered regulation due to changes in chromosome topology

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Un environnement pour le tracé de rayons utilisant une modélisation par arbre de construction

Le tracé de rayons est désormais un algorithme classique pour la visualisation en synthèse d'images. Nous nous sommes cependant efforcés de ne pas le considérer comme un simple algorithme de visualisation mais comme un algorithme plus général de simulation de transfert d'énergie au sein d'un environnement géométrique. Ce choix a conduit à la définition d'un modèle géométrique indépendant du modèle de rendu qui lui est associé. Ce modèle utilise une méthode par arbre de construction (CSG) avec deux améliorations essentielles: l'utilisation d'un graphe au lieu d'un arbre ainsi que la possibilité d'associer des propriétés à n'importe quel objet du modèle. L'algorithme de calcul d'intersection entre un rayon et un objet est spécialement adapte à ce modèle, et il utilise une technique d'accélération nouvelle, basée sur l'utilisation d'englobant appelés boites englobantes généralisées, palliant certains inconvénients des techniques classiques. L'algorithme de rendu a été rendu générique, ce qui permet de changer facilement d'implémentation de l'algorithme de rendu. Les modèles classiques (Lambert et Phong) sont présentés en détail. Enfin, nous présentons trois applications de notre environnement: l'utilisation de nouveaux systèmes de perspectives, la visualisation de densités volumiques et de primitives de lumière, ainsi qu'une version parallèle de notre algorithme.No abstrac

Détection de zones (précurseurs thermiques de la formation des masses d'air chaud, véhicules de la pollution atmosphérique) par la simulation du transfert radiatif à l'aide de tracé de rayon

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An automatic adaptive surface reconstruction from ellipsoidal skeleton

3D reconstruction is a large area of investigation. The accuracy of the 3D geometry may be dynamically adjusted to constantly provide instantaneous interaction with virtual organs for a given error tolerance. In trying to fulfill those requirements, the authors propose an anlytical approach using the implicit surfaces model. A hierarchical mathematical expression of a 3D solid represented by 3D points including the inner ones is automatically built by progressively positioning implicit primitives within the point cloud (usually acquired from CT-scan or MRI images). Each new primitive addition results in a more precise geometrical approximation of the 3D object, thus generating what is called a semantic level. At last, to reliably conduct the surface-fitting process, the authors propose the tabu metaheuristic that will take any semantic level as initial solution while using an inexpensive surface-to-boundary error measurement. Once those data have been permanently stored, the rendering stage is then performed on the fly using adaptive discretization step, thus producing multiple levels of detail. In this scope, a generic algorithm to guide the polygonization of implicit objects with multiple connected components is also proposed. The analytical model that has been developed is called ellipsoidal skeleton (e-skeleton). Each set of automatically adjusted implicit primitives is converted to a classical Constructive Solid Geometry tree that seamlessly integrates the deformation function and parameters obtained during the surface-fitting proces