52 research outputs found
Ătude du polymorphisme rs3846662 de lâHMGCR dans le cerveau et le systĂšme pĂ©riphĂ©rique
Dans cette thĂšse, lâimpact du polymorphisme rs3846662 sur lâĂ©pissage alternatif de la 3-hydroxy-3-mĂ©thylglutaryl coenzyme A rĂ©ductase (HMGCR) a Ă©tĂ© investiguĂ© in vivo, chez des patients atteints dâhypercholestĂ©rolĂ©mie familiale (HF) ou de maladie dâAlzheimer (MA). Le premier manuscrit adresse la problĂ©matique de la normalisation de la quantification relative des ARNm par PCR quantitative. Les dĂ©couvertes prĂ©sentĂ©es dans ce manuscrit nous ont permis de dĂ©terminer avec un haut niveau de confiance les gĂšnes de rĂ©fĂ©rence Ă utiliser pour la quantification relative des niveaux dâARNm de lâHMGCR dans des Ă©chantillons de sang (troisiĂšme manuscrit) et de tissus cĂ©rĂ©braux post-mortem (quatriĂšme manuscrit).
Dans le deuxiĂšme manuscrit, nous dĂ©montrons grĂące Ă lâemploi de trois cohortes de patients distinctes, soit la population canadienne française du QuĂ©bec et les deux populations nord amĂ©ricaines « Alzheimerâs Disease Cooperative Study (ADCS) » et « Alzheimerâs Disease Neuroimaging Initiative (ADNI) », que le gĂ©notype AA au locus rs3846662 confĂšre Ă ces porteurs une protection considĂ©rable contre la MA. Les femmes porteuses de ce gĂ©notype voient leur risque de MA diminuer de prĂšs de 50% et lâĂąge dâapparition de leurs premiers symptĂŽmes retarder de 3.6 ans. Les porteurs de lâallĂšle Ă risque APOE4 voient pour leur part leurs niveaux de plaques sĂ©niles et dĂ©gĂ©nĂ©rescences neurofibrillaires diminuer significativement en prĂ©sence du gĂ©notype AA. Enfin, les individus atteints de dĂ©ficit cognitif lĂ©ger et porteurs Ă la fois de lâallĂšle APOE4 et du gĂ©notype protecteur AA voient leur risque de convertir vers la MA chuter de 76 Ă 27%.
Dans le troisiĂšme manuscrit, nous constatons que les individus atteints dâHF et porteurs du gĂ©notype AA ont, contrairement au modĂšle Ă©tabli chez les gens normaux, des niveaux plus Ă©levĂ©s de cholestĂ©rol total et de LDL-C avant traitement comparativement aux porteurs de lâallĂšle G. Le fait que cette association nâest observĂ©e que chez les non porteurs de lâAPOE4 et que les femmes porteuses du gĂ©notype AA prĂ©sentent Ă la fois une augmentation des niveaux dâARNm totaux et une rĂ©sistance aux traitements par statines, nous indique que ce gĂ©notype influencerait non seulement lâĂ©pissage alternatif, mais Ă©galement la transcription de lâHMGCR. Comme une revue exhaustive de la littĂ©rature ne rĂ©vĂšle aucune Ă©tude abondant dans ce sens, nos rĂ©sultats suggĂšrent lâexistence de joueurs encore inconnus qui viennent influencer la relation entre le gĂ©notype AA, lâĂ©pissage alternatif et les niveaux dâARNm de lâHMGCR.
Dans le quatriĂšme manuscrit, lâabsence dâassociations entre le gĂ©notype AA et les niveaux dâARNm Î13 ou de protĂ©ines HMGCR nous suggĂšre fortement que ce polymorphisme est non fonctionnel dans le SNC affectĂ© par la MA. Une Ă©tude approfondie de la littĂ©rature nous a permis dâĂ©tayer cette hypothĂšse puisque les niveaux de HNRNPA1, la ribonuclĂ©oprotĂ©ine influencĂ©e par lâallĂšle au locus rs3846662, sont considĂ©rablement rĂ©duits dans la MA et le vieillissement. Il est donc proposĂ© que les effets protecteurs contre la MA associĂ©s au gĂ©notype AA soient le rĂ©sultat dâune action indirecte sur le processus physiopathologique.In this thesis, the impact of rs3846662 polymorphism on the alternative splicing of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) was investigated in vivo, in patients with familial hypercholesterolemia (FH) or Alzheimer disease (AD). The first manuscript addresses the issue of normalization in relative quantification of mRNA by quantitative PCR. The findings presented in this manuscript have allowed us to determine with a high level of certainty the appropriate reference genes to use for the relative quantification of HMGCR mRNA levels in blood samples (third manuscript) and postmortem brain tissues (fourth manuscript).
In the second manuscript, we demonstrate through the use of three independent cohorts, namely the French Canadian population of Quebec and the two North American populations named "Alzheimer's Disease Cooperative Study (ADCS)" and "Alzheimer's Disease Neuroimaging Initiative (ADNI) ", that the AA genotype at locus rs3846662 confers significant protection against AD. Women carrying this genotype decrease their risk of AD by about 50%, and delay their age of onset of 3.6 years. For their part, individuals carrying both the APOE4 risk allele and the AA genotype have decreased levels of senile plaques and neurofibrillary tangles compared to individuals carrying both the APOE4 and HMGCR G alleles. Finally, individuals suffering from mild cognitive impairment and carrying both the APOE4 risk allele and the protective AA genotype see their risk of converting to AD drop from 76% to 27%.
In the third manuscript, contrary to the model described in normal subjects, we discovered that individuals with FH carrying the AA genotype have higher levels of total cholesterol and LDL-C before treatment compared to the carriers of the G allele. This latter association is observed only in non-carriers of the APOE4 risk allele. Furthermore, women carrying the AA genotype have both an increase in total HMGCR mRNA levels and a decrease response to statin treatment. These results suggest the AA genotype has an impact not only on the alternative splicing, but also on the transcription of HMGCR. Since an exhaustive review of the literature has reveal no studies corroborating this hypothesis, our results suggest the existence of yet unknown players influencing the relationships between the AA genotype, alternative splicing and the mRNA levels of HMGCR.
In the fourth manuscript, we uncovered no association between the AA genotype and Î13 mRNA or HMGCR protein levels. This strongly suggests that the rs3846662 polymorphism is not functional in the CNS affected by AD. A thorough study of the literature enabled us to support this hypothesis since the levels of HNRNPA1, the ribonucleoprotein influenced by the allele status at rs3846662 locus, are significantly reduced in AD and aging. Accordingly, we propose that the protective effects of the AA genotype against AD may be mediated through indirect effects on the physiopathology of the disease
Characterization of bacteriophage T7-Ah reveals its lytic activity against a subset of both mesophilic and psychrophilic Aeromonas salmonicida strains
Aeromonas salmonicida strains cause problematic bacterial infections in the aquaculture industry worldwide. The genus Aeromonas includes both mesophilic and psychrophilic species. Bacteriophages that infect Aeromonas spp. strains are usually specific for mesophilic or psychrophilic species; only a few bacteriophages can infect both types of strains. In this study, we characterized the podophage T7-Ah, which was initially found to infect the Aeromonas salmonicida HER1209 strain. The burst size of T7-Ah against its original host is 72 new virions per infected cell, and its burst time is 30 minutes. It has been found that this phage can lyse both mesophilic and psychrophilic A. salmonicida strains, as well as one strain of Escherichia coli. Its genome comprises 40,153 bp of DNA and does not contain any recognizable toxin or antibiotic resistance genes. The adsorption rate of the phage on highly sensitive bacterial strains was variable and could not be related to the presence or absence of a functional A-layer on the surface of the bacterial strains. The lipopolysaccharide migration patterns of both resistant and sensitive bacterial strains were also studied and compared to investigate the nature of the potential receptor of this phage on the bacterial surface. This study sheds light on the surprising diversity of lifestyles of the bacterial strains sensitive to phage T7-Ah and opens the door to the potential use of this phage against A. salmonicida infections in aquaculture
Function and Comorbidities of Apolipoprotein E in Alzheimer's Disease
Alzheimer's disease (AD)âthe most common type of dementia among the elderlyârepresents one of the most challenging and urgent medical mysteries affecting our aging population. Although dominant inherited mutation in genes involved in the amyloid metabolism can elicit familial AD, the overwhelming majority of AD cases, dubbed sporadic AD, do not display this Mendelian inheritance pattern. Apolipoprotein E (APOE), the main lipid carrier protein in the central nervous system, is the only gene that has been robustly and consistently associated with AD risk. The purpose of the current paper is thus to highlight the pleiotropic roles and the structure-function relationship of APOE to stimulate both the functional characterization and the identification of novel lipid homeostasis-related molecular targets involved in AD
Characteristics of meiofauna in extreme marine ecosystems: a review
Extreme marine environments cover more than 50% of the Earthâs surface and offer many opportunities for investigating the biological responses and adaptations of organisms to stressful life conditions. Extreme marine environments are sometimes associated with ephemeral and unstable ecosystems, but can host abundant, often endemic and well-adapted meiofaunal species. In this review, we present an integrated view of the biodiversity, ecology and physiological responses of marine meiofauna inhabiting several extreme marine environments (mangroves, submarine caves, Polar ecosystems, hypersaline areas, hypoxic/anoxic environments, hydrothermal vents, cold seeps, carcasses/sunken woods, deep-sea canyons, deep hypersaline anoxic basins [DHABs] and hadal zones). Foraminiferans, nematodes and copepods are abundant in almost all of these habitats and are dominant in deep-sea ecosystems. The presence and dominance of some other taxa that are normally less common may be typical of certain extreme conditions. Kinorhynchs are particularly well adapted to cold seeps and other environments that experience drastic changes in salinity, rotifers are well represented in polar ecosystems and loriciferans seem to be the only metazoan able to survive multiple stressors in DHABs. As well as natural processes, human activities may generate stressful conditions, including deoxygenation, acidification and rises in temperature. The behaviour and physiology of different meiofaunal taxa, such as some foraminiferans, nematode and copepod species, can provide vital information on how organisms may respond to these challenges and can provide a warning signal of anthropogenic impacts. From an evolutionary perspective, the discovery of new meiofauna taxa from extreme environments very often sheds light on phylogenetic relationships, while understanding how meiofaunal organisms are able to survive or even flourish in these conditions can explain evolutionary pathways. Finally, there are multiple potential economic benefits to be gained from ecological, biological, physiological and evolutionary studies of meiofauna in extreme environments. Despite all the advantages offered by meiofauna studies from extreme environments, there is still an urgent need to foster meiofauna research in terms of composition, ecology, biology and physiology focusing on extreme environments
Genetic markers of neurodegeneration: a role for paraoconase 1 in sporadic Alzheimer's disease?
Mounting evidence points to increased oxidative stress and disruption of cholesterol homeostasis as being crucial events implicated in Alzheimer's disease (AD) etiopathology. Paraoxonase1 (PON1) is a high-density lipoprotein-associated antioxidant enzyme that functions to protect both lipids and the cholinergic system, the primary neurotransmitter system affected in AD, from respectively oxidation and organophosphate compounds. Using a large and homogeneous cohort of Quebec citizens, we therefore sought to investigate the involvement of PON1 in AD. We found that a single nucleotide polymorphism (SNP) in the PON1 gene not only exerts an AD risk enhancing effect but also a paradoxical survival rate increasing effect and a later age at AD symptom onset. This SNP is also significantly associated, sometimes in opposite directions for both sexes, with beta-amyloid levels, senile plaque accumulation and choline acetyltransferase activity in numerous brain areas. Thus, these results suggest a prominent role for PON1 in the etiopathology of AD.Maintes preuves confirment l'implication d'une augmentation du stress oxydatif et d'une perturbation de l'homĂ©ostasie du systĂšme cholestĂ©ro-lipidique dans le dĂ©veloppement de la maladie d'Alzheimer (MA). La paraoxonase 1 (PON1), une enzyme antioxydante liĂ©e aux lipoprotĂ©ines de haute densitĂ©, est reconnue pour sa capacitĂ© de protĂ©ger tant les lipides que le systĂšme cholinergique, l'un des premiers systĂšmes de neurotransmetteurs affectĂ©s par la MA, contre respectivement l'oxydation et les composĂ©s organophosphorĂ©s. En utilisant un large groupe de citoyens quĂ©bĂ©cois, nous dĂ©montrons qu'un polymorphisme gĂ©nĂ©tique de la PON1 augmente le risque de dĂ©velopper la MA tout en repoussant paradoxalement l'Ăąge de mort et de dĂ©but de la maladie. Ce polymorphisme affecte, de façon parfois opposĂ©e chez les deux sexes, les niveaux de protĂ©ine bĂȘta-amyloĂŻde, de plaques sĂ©niles, et d'activitĂ© de l'acĂ©tylcholine transfĂ©rase dans plusieurs rĂ©gions du cerveau. Nos rĂ©sultats suggĂšrent donc un rĂŽle prĂ©pondĂ©rant de la PON1 dans le dĂ©veloppement de la MA
Complications associées aux Cathéters à Site d'Injection Implantable (CSII) (étude prospective dans deux services de cancérologie de l'HÎpital de Clermont-Ferrand)
Les Cathéters à Site d'Injection Implantable (CSII) sont couramment utilisés chez les patients atteints d'un cancer pour administrer la chimiothérapie ou la nutrition parentérale. L'auteur s'intéresse à deux aspects : intensité de la douleur et confort du patient durant et aprÚs la pose du CSII et observation des complications précoces ou tardives induites par les CSII utilisés pour la chimiothérapie, en particulier les complications infectieuses. Du 12-05-08 au 10-07-08 (60 jours), nous avons suivi 248 patients (ùge 24-85) porteurs d'un CSII dans 2 services d'oncologie du CHRU de Clermont-Ferrand. L'insertion a été effectuée sous anesthésie locale pour 86% des patients ; 32% des patients ont souffert de douleur pendant la pose (IVA> à 4). Neuf complications ont été observées : 6 non infectieuses et 3 infectieuses (germes en cause : 1 S. aureus, 1 E. coli et un germe non identifié). Le taux relativement élevé de douleur ressentie lors de la pose du CSII est vraisemblablement lié au taux élevé de pose sous anesthésie locale. Les infections représentent un tiers des complications ; toutes ont été traitées avec succÚs par antibiothérapie. Le taux d'infection rapporté au nombre de jours d'utilisation est de 0,21/1000 jours, mais nous pensons qu'un meilleur indicateur serait le taux d'infection rapporté au nombre de jours d'hospitalisation ; dans notre étude, pour 882 jours d'hospitalisation, ce taux ressort à 3,4 infections/1000 jours d'hospitalisation.CLERMONT FD-BCIU-Santé (631132104) / SudocLYON1-BU Santé (693882101) / SudocSudocFranceF
LE MARIAGE POLYGAME ET LE DROIT INTERNATIONAL PRIVĂ QUĂBĂCOIS DANS UNE PERSPECTIVE DE DROIT COMPARĂ
Bien que le mariage polygame y soit illĂ©gal, le Canada, en tant que terre dâimmigration, est depuis longtemps confrontĂ© Ă cette institution en matiĂšre migratoire et familiale. Incidemment, la question de la validitĂ© du mariage polygame suivant les rĂšgles du droit international privĂ© se pose, entraĂźnant dans son sillage des doutes quant Ă la capacitĂ© de notre systĂšme juridique Ă rĂ©gir une institution qui lui est Ă©trangĂšre et dont certains allĂšguent lâincompatibilitĂ© avec lâordre public. Dans le prĂ©sent texte, pour les fins du concours Matthieu-Bernard, les auteures examinent ce qui adviendrait dâune demande en divorce prĂ©sentĂ©e par la seconde Ă©pouse dâun mĂ©nage polygame. De façon plus gĂ©nĂ©rale, elles Ă©tudient les effets que peut avoir un mariage polygame contractĂ© Ă lâĂ©tranger dans lâordre juridique quĂ©bĂ©cois, selon que ce mariage soit dĂ©clarĂ© valide ou invalide. Dans lâhypothĂšse dâun mariage valide selon les rĂšgles de droit international privĂ© quĂ©bĂ©cois, câest la notion dâordre public, tant international quâinterne, qui pourrait sâopposer Ă la reconnaissance et Ă la production dâeffets juridiques dâun mariage polygame. AprĂšs un examen du contenu de lâordre public interne et international, les auteures concluent que la reconnaissance de la validitĂ© dâun mariage polygame et de certains effets y Ă©tant rattachĂ©s ne serait pas contraire Ă ces notions. Dans lâhypothĂšse oĂč le mariage serait dĂ©clarĂ© invalide, câest la possibilitĂ© pour les tribunaux de prononcer la nullitĂ© de ce mariage, ainsi que le risque de contestation constitutionnelle en vertu de la Charte canadienne des droits et libertĂ©s, qui amĂšnent les auteures Ă se questionner. Elles concluent que le prononcĂ© de la nullitĂ© constituerait une atteinte justifiĂ©e Ă la libertĂ© de religion et revĂȘtirait de grands avantages sâil permet de faire appel Ă la notion de putativitĂ© du mariage.Although polygamous marriage is illegal, Canada, as an immigration country, has long been confronted to that institution in migratory and family matters. Incidentally, whether polygamous marriage is valid or not according to private international law rules has become a necessary question. It opens more widely toward the capacity of our legal system to govern this foreign institution that some believe to be incompatible with public policy. In this article, written for the Matthieu-Bernard contest, the authors examine what may happen to a divorce petition presented by the second wife of a polygamous household. More generally, they study what legal effects a polygamous marriage, celebrated outside Canada, can produce in the QuĂ©bec legal system according to two different hypotheses, the validity or invalidity of the marriage. If a marriage was declared valid according to QuĂ©bec private international law rules, it is the public policy exception, both international and local, that could oppose the polygamous marriageâs recognition and production of legal effects. After studying the content of the public policy exception, both at the international and local levels, the authors conclude that it does not oppose the recognition of the validity of a polygamous marriage nor the production of certain legal effects. If a marriage was declared invalid, it is the possibility for a tribunal to declare the marriage null, and the incidental risk of a Canadian Charter of Rights and Freedoms challenge, that the authors study. They conclude that a declaration of nullity would constitute a justified violation of freedom of religion and would be advantageous if the wedding could be granted as putative, thus permitting the polygamous marriage to produce certain legal effects
Le mariage polygame et le droit international privé québécois dans une perspective de droit comparé
Although polygamous marriage is illegal, Canada, as an immigration country, has long been confronted to that institution in migratory and family matters. Incidentally, whether polygamous marriage is valid or not according to private international law rules has become a necessary question. It opens more widely toward the capacity of our legal system to govern this foreign institution that some believe to be incompatible with public policy. In this article, written for the Matthieu-Bernard contest, the authors examine what may happen to a divorce petition presented by the second wife of a polygamous household. More generally, they study what legal effects a polygamous marriage, celebrated outside Canada, can produce in the QuĂ©bec legal system according to two different hypotheses, the validity or invalidity of the marriage. If a marriage was declared valid according to QuĂ©bec private international law rules, it is the public policy exception, both international and local, that could oppose the polygamous marriageâs recognition and production of legal effects. After studying the content of the public policy exception, both at the international and local levels, the authors conclude that it does not oppose the recognition of the validity of a polygamous marriage nor the production of certain legal effects. If a marriage was declared invalid, it is the possibility for a tribunal to declare the marriage null, and the incidental risk of a Canadian Charter of Rights and Freedoms challenge, that the authors study. They conclude that a declaration of nullity would constitute a justified violation of freedom of religion and would be advantageous if the wedding could be granted as putative, thus permitting the polygamous marriage to produce certain legal effects.Bien que le mariage polygame y soit illĂ©gal, le Canada, en tant que terre dâimmigration, est depuis longtemps confrontĂ© Ă cette institution en matiĂšre migratoire et familiale. Incidemment, la question de la validitĂ© du mariage polygame suivant les rĂšgles du droit international privĂ© se pose, entraĂźnant dans son sillage des doutes quant Ă la capacitĂ© de notre systĂšme juridique Ă rĂ©gir une institution qui lui est Ă©trangĂšre et dont certains allĂšguent lâincompatibilitĂ© avec lâordre public. Dans le prĂ©sent texte, pour les fins du concours Matthieu-Bernard, les auteures examinent ce qui adviendrait dâune demande en divorce prĂ©sentĂ©e par la seconde Ă©pouse dâun mĂ©nage polygame. De façon plus gĂ©nĂ©rale, elles Ă©tudient les effets que peut avoir un mariage polygame contractĂ© Ă lâĂ©tranger dans lâordre juridique quĂ©bĂ©cois, selon que ce mariage soit dĂ©clarĂ© valide ou invalide. Dans lâhypothĂšse dâun mariage valide selon les rĂšgles de droit international privĂ© quĂ©bĂ©cois, câest la notion dâordre public, tant international quâinterne, qui pourrait sâopposer Ă la reconnaissance et Ă la production dâeffets juridiques dâun mariage polygame. AprĂšs un examen du contenu de lâordre public interne et international, les auteures concluent que la reconnaissance de la validitĂ© dâun mariage polygame et de certains effets y Ă©tant rattachĂ©s ne serait pas contraire Ă ces notions. Dans lâhypothĂšse oĂč le mariage serait dĂ©clarĂ© invalide, câest la possibilitĂ© pour les tribunaux de prononcer la nullitĂ© de ce mariage, ainsi que le risque de contestation constitutionnelle en vertu de la Charte canadienne des droits et libertĂ©s, qui amĂšnent les auteures Ă se questionner. Elles concluent que le prononcĂ© de la nullitĂ© constituerait une atteinte justifiĂ©e Ă la libertĂ© de religion et revĂȘtirait de grands avantages sâil permet de faire appel Ă la notion de putativitĂ© du mariage.Leduc Ariane, Raby MĂ©lanie, Scott ValĂ©rie. Le mariage polygame et le droit international privĂ© quĂ©bĂ©cois dans une perspective de droit comparĂ©. In: Revue QuĂ©bĂ©coise de droit international, volume 21-1, 2008. pp. 165-209
Le mariage polygame et le droit international privé québécois dans une perspective de droit comparé
Although polygamous marriage is illegal, Canada, as an immigration country, has long been confronted to that institution in migratory and family matters. Incidentally, whether polygamous marriage is valid or not according to private international law rules has become a necessary question. It opens more widely toward the capacity of our legal system to govern this foreign institution that some believe to be incompatible with public policy. In this article, written for the Matthieu-Bernard contest, the authors examine what may happen to a divorce petition presented by the second wife of a polygamous household. More generally, they study what legal effects a polygamous marriage, celebrated outside Canada, can produce in the QuĂ©bec legal system according to two different hypotheses, the validity or invalidity of the marriage. If a marriage was declared valid according to QuĂ©bec private international law rules, it is the public policy exception, both international and local, that could oppose the polygamous marriageâs recognition and production of legal effects. After studying the content of the public policy exception, both at the international and local levels, the authors conclude that it does not oppose the recognition of the validity of a polygamous marriage nor the production of certain legal effects. If a marriage was declared invalid, it is the possibility for a tribunal to declare the marriage null, and the incidental risk of a Canadian Charter of Rights and Freedoms challenge, that the authors study. They conclude that a declaration of nullity would constitute a justified violation of freedom of religion and would be advantageous if the wedding could be granted as putative, thus permitting the polygamous marriage to produce certain legal effects.Bien que le mariage polygame y soit illĂ©gal, le Canada, en tant que terre dâimmigration, est depuis longtemps confrontĂ© Ă cette institution en matiĂšre migratoire et familiale. Incidemment, la question de la validitĂ© du mariage polygame suivant les rĂšgles du droit international privĂ© se pose, entraĂźnant dans son sillage des doutes quant Ă la capacitĂ© de notre systĂšme juridique Ă rĂ©gir une institution qui lui est Ă©trangĂšre et dont certains allĂšguent lâincompatibilitĂ© avec lâordre public. Dans le prĂ©sent texte, pour les fins du concours Matthieu-Bernard, les auteures examinent ce qui adviendrait dâune demande en divorce prĂ©sentĂ©e par la seconde Ă©pouse dâun mĂ©nage polygame. De façon plus gĂ©nĂ©rale, elles Ă©tudient les effets que peut avoir un mariage polygame contractĂ© Ă lâĂ©tranger dans lâordre juridique quĂ©bĂ©cois, selon que ce mariage soit dĂ©clarĂ© valide ou invalide. Dans lâhypothĂšse dâun mariage valide selon les rĂšgles de droit international privĂ© quĂ©bĂ©cois, câest la notion dâordre public, tant international quâinterne, qui pourrait sâopposer Ă la reconnaissance et Ă la production dâeffets juridiques dâun mariage polygame. AprĂšs un examen du contenu de lâordre public interne et international, les auteures concluent que la reconnaissance de la validitĂ© dâun mariage polygame et de certains effets y Ă©tant rattachĂ©s ne serait pas contraire Ă ces notions. Dans lâhypothĂšse oĂč le mariage serait dĂ©clarĂ© invalide, câest la possibilitĂ© pour les tribunaux de prononcer la nullitĂ© de ce mariage, ainsi que le risque de contestation constitutionnelle en vertu de la Charte canadienne des droits et libertĂ©s, qui amĂšnent les auteures Ă se questionner. Elles concluent que le prononcĂ© de la nullitĂ© constituerait une atteinte justifiĂ©e Ă la libertĂ© de religion et revĂȘtirait de grands avantages sâil permet de faire appel Ă la notion de putativitĂ© du mariage.Leduc Ariane, Raby MĂ©lanie, Scott ValĂ©rie. Le mariage polygame et le droit international privĂ© quĂ©bĂ©cois dans une perspective de droit comparĂ©. In: Revue QuĂ©bĂ©coise de droit international, volume 21-1, 2008. pp. 165-209
Evaluation of the Human Body Mask Effects on GNSS Wearable Devices for Outdoor Pedestrian Navigation Using Fisheye Sky Views
International audienceAn increasing number of Global Navigation Satellite Systems (GNSS)-based wearable devices emerged in our daily life in recent years. The utilities of these wearable devices vary from entertainment applications to safety and reliability-critical applications (such as blind people guidance, health monitoring, behavior-based soft mobility insurance, etc.). A key challenge for safety and reliability-critical applications using GNSS is the tracking of reliable and high quality signals in stringent environments. One particularity for wearable devices compared to other GNSS devices is that GNSS signals can be masked by not only the surrounding obstacles but also by the body of the users. Many research work addresses the impact of the surrounding obstacles on GNSS signal receptions whereas very few research studies the impact of human body mask.The objective of this paper is to investigate the impact of the user body mask on wearable GNSS devices. By fixing a fisheye camera on GNSS wearable devices on two body parts of a pedestrian, i.e., hand and foot, the sky view representing the âpoint of viewâ of the device can be obtained. The images are first segmented to distinguish the sky from the obstacles. The GNSS satellites can be then classified as Line-of-Sight (LOS) and Non-Line-of-Sight (NLOS) by projecting them on the fisheye images. The experimentation results show that, in an open sky context, the mean percentage of the sky view for the receiver on the foot during the stance phase of a walking cycle is higher than that in the hand. This leads to, on average, a higher number of visible satellites for foot-mounted receivers and better satellite geometry. The trajectory of the foot-mounted device is generally more accurate with less uncertainty in all the evaluated environments (open sky, suburban, deep urban and urban canyon). This preliminary research leads to a counterintuitive outcome since the foot-mounted GNSS device is globally able to provide better positioning than the hand-held device. Accordingly, the foot-mounted GNSS device could be further considered as a more reliable fusion source for hybridization positioning systems used for safety-critical or reliability-critical applications
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