Coverings of singular curves over finite fields

International audienceWe prove that if $f : Y\longrightarrow X$ is a finite fiat morphism between two reduced absolutely irreducible algebraic projective curves defined over the finite field {\sb F}_q, then \mid \sharp Y({\sb F}_q) - \sharp X({\sb F}_q)\mid \leq 2({\pi}_Y - {\pi}_X)\sqrt q, where $\pi_C$ is the arithmetic genus of a curve $C$. As application, we give some character sum estimation on singular curves

On the characteristic polynomials of the Frobenius endomorphism for projective curves over finite fields

International audienceWe give a formula for the number of rational points of projective algebraic curves defined over a finite field, and a bound ''á la Weil'' for connected ones. More precisely, we give the characteristic polynomials of the Frobenius endomorphism on the étale l-adic cohomology groups of the curve. Finally, as an analogue of Artin's holomorphy conjecture, we prove that, if $Y\longrightarrow X$ is a finite flat morphism between two varieties over a finite field, then the characteristic polynomial of the Frobenius morphism on the i-th l-adic cohomology group with compact support of $X$ divides that of $Y$ for any i. We are then enable to give an estimate for the number of rational points in a flat covering of curves

M & L Jaargang 23/1

Anna Bergmans Wilt gij wel zijn wilt gij rusten, zoek het niet op vreemde kusten. De woning met atelier van Oscar Algoet (1862-1937), decoratieschilder in Leuven. [Oscar Algoet.]Zijn levenswandel in de schaduw van de grootmeesters van de neogotiek getrouw, ging decoratieschilder Oscar Algoet na overlijden op in anonimiteit. Doordrongen van de leerstellingen van de Sint-Lucasscholen en zich lavend aan de modellen in hun tijdschriften, zou hij deze toepassen op zijn eigen woning met atelier, op de grondvesten van het Leuvense Augustijnenklooster: niet deze van een kunstenaar maar van een begenadigd ambachtsman waar, getuige Anna Bergmans, het gezinsleven centraal bleef staan.Jean-Marc Basyn (vertaling H.-J. Van Den Bossche) De architecten Brunfaut, een sociaal bewogen oeuvre. [The architects Brunfaut and their socially conscious oeuvre.]Als een hechte dynastie zouden de architecten Fernand, Gaston en Maxime Brunfaut vanuit hun -progressief socialistische overtuiging theoretisch, politiek en stedenbouwkundig de krijtlijnen uitzetten van de moderne metropool: een Groot-Brussel waar transport, openbare voorzieningen en behuizing het welzijn zouden dienen van de collectiviteit.Vormelijk aanleunend bij het modernisme is hun oeuvre dat van kantoorgebouwen, een Modelwijk, spoor- en luchtvaartinfrastructuren, maar niet in het minst hospitalen en het roemruchte sanatoriumcomplex in Tombeek.Françoise Aubry (vertaling Marcel M. Celis) Het Herenhuis Aubecq. [The Aubecq mansion.]In 1948 bleek het flamboyante herenhuis van industrieel Octave Aubecq, waarvoor Victor Horta carte blanche verkregen had, een luttele maanden te jong om wettelijke bescherming als monument te kunnen overwegen. Sloping was onafwendbaar, maar een eeuw na oplevering blijven granieten onderdelen van de gevels ontredderd wachten op hun hypothetische anastylose ooit en ergens.Bij de gratie van heropgedoken interieurfotos blikt Françoise Aubry terug op dit verdwenen meesterwerk, waarvan haar eigen grootvader in een niet zo ver verleden althans de inboedel voor oorlogsgeweld wist te vrijwaren.Summar

ALGEBRAIC GEOMETRY CODES OVER ABELIAN SURFACES CONTAINING NO ABSOLUTELY IRREDUCIBLE CURVES OF LOW GENUS

We provide a theoretical study of Algebraic Geometry codes constructed from abelian surfaces defined over finite fields. We give a general bound on their minimum distance and we investigate how this estimation can be sharpened under the assumption that the abelian surface does not contain low genus curves. This approach naturally leads us to consider Weil restrictions of elliptic curves and abelian surfaces which do not admit a principal polarization

A Weil theorem for singular curves

International audienceWe generalize Weil's theorem on the number of rational points of smooth curves over a finite field to singular ones

Simultaneous analysis of distinct Omics data sets with integration of biological knowledge: Multiple Factor Analysis approach

<p>Abstract</p> <p>Background</p> <p>Genomic analysis will greatly benefit from considering in a global way various sources of molecular data with the related biological knowledge. It is thus of great importance to provide useful integrative approaches dedicated to ease the interpretation of microarray data.</p> <p>Results</p> <p>Here, we introduce a data-mining approach, Multiple Factor Analysis (MFA), to combine multiple data sets and to add formalized knowledge. MFA is used to jointly analyse the structure emerging from genomic and transcriptomic data sets. The common structures are underlined and graphical outputs are provided such that biological meaning becomes easily retrievable. Gene Ontology terms are used to build gene modules that are superimposed on the experimentally interpreted plots. Functional interpretations are then supported by a step-by-step sequence of graphical representations.</p> <p>Conclusion</p> <p>When applied to genomic and transcriptomic data and associated Gene Ontology annotations, our method prioritize the biological processes linked to the experimental settings. Furthermore, it reduces the time and effort to analyze large amounts of 'Omics' data.</p

What was your fracture risk evaluated by FRAX® the day before your osteoporotic fracture?

Osteoporotic fracture (OF) is one of the major causes of morbidity and mortality in industrialized countries. Switzerland is among the countries with the greatest risk. Our aim was (1) to calculate the FRAX® in a selected Swiss population the day before the occurrence of an OF and (2) to compare the results with the proposed Swiss FRAX® thresholds. The Swiss Association Against Osteoporosis proposed guidelines for the treatment of osteoporosis based on age-dependent thresholds. To identify a population at a very high risk of osteoporotic fracture, we included all consecutive patients in the active OF pathway cohort from the Lausanne University Hospital, Switzerland. FRAX® was calculated with the available data the day before the actual OF. People with a FRAX® body mass index (BMI) or a FRAX® (bone mineral density) BMD lower than the Swiss thresholds were not considered at high risk. Two-hundred thirty-seven patients were included with a mean age of 77.2years, and 80% were female. Major types of fracture included hip (58%) and proximal humerus (25%) fractures. Mean FRAX® BMI values were 28.0, 10.0, 13.0, 26.0, and 37.0% for age groups 50-59, 60-69, 70-79, and 80-89years old, respectively. Fifty percent of the population was not considered at high risk by the FRAX® BMI. FRAX® BMD was available for 95 patients, and 45% had a T score < −2.5 standard deviation. Only 30% of patients with a normal or osteopenic BMD were classified at high risk by FRAX® BMD. The current proposed Swiss thresholds were not able to classify at high risk in 50 to 70% of the studied population the day before a major O

Iron-related transcriptomic variations in Caco-2 cells: in silico perspectives.

International audienceThe iron absorption by duodenal enterocytes is a key step of its homeostasis. But the control of this absorption is complex and cannot be fully explicated with present knowledge. In a global transcriptome approach, we identified 60 genes over-expressed in hemin (iron) overload in Caco-2 cells, an in vitro model of duodenal enterocytes. The challenge from there was to identify the affected molecular mechanisms and achieve a biological interpretation for that cluster. In that purpose, we built up a functional annotation method combining evidence and literature. Our method identified four pathways in the Process hierarchy of the Gene Ontology (GO): lipid metabolism, amino acid and cofactor metabolism, response to stimulus and transport. The accuracy of this functional profile is supported by the identification of known pathways associated with the iron overload (response to oxidative stress, glutathione metabolism). But our method also suggests new hypotheses on the regulation of iron uptake in Caco-2 cells. It is hypothesized that plasma membrane remodeling and vesicular recycling could be a potential modulator of iron transport proteins activities. These assumptions yet require a biological validation and they will therefore direct further research. Our functional annotation method is a valuable tool designed to help the biologist understand the biological links between the genes of a cluster, elaborate working hypotheses and direct future work. This work is also a validation 'by hand' of a biomedical text-mining system