Guide québécois d’application de l’Indice de Qualité Morphologique (IQM) des cours d’eau.

L’atteinte de l’objectif d’aucune perte nette des milieux hydriques au Québec nécessite de revoir les pratiques de gestion des cours d’eau. Pour ce faire, les caractéristiques définissant ce qu’est un cours d’eau naturel, intègre et fonctionnel doivent d’abord faire consensus et s’organiser au sein d’un langage commun. Il nous faut collectivement une méthode pour prendre la mesure des pertes et des gains écologiques. Il s’agit de se doter des outils pour faire le bilan de la dégradation historique des cours d’eau et minimiser les dégradations à venir, mais aussi et surtout pour bien définir ce qui doit être préservé ou restauré. Ce langage commun est fourni par l’Indice de Qualité Morphologique (IQM). Il se compose de 28 indicateurs, répartis en trois catégories, qui permettent l’obtention d’un score synthétique sur une échelle entre 0 et 1. De plus en plus utilisé au Québec, cet indice constitue une approche prometteuse pour une priorisation de sites d’interventions de restauration dans les cours d’eau ou pour prioriser des secteurs à protéger par exemple. Son emphase sur les formes et processus à l’échelle du paysage lui confère l’avantage de permettre l’évaluation de l’état des milieux hydriques à une échelle qui ne serait pas réaliste par l’entremise d’indices biotiques. Cependant, l’IQM classique (Rinaldi et al., 2013, 2016a) a été développé et réfléchi pour un contexte alpin – Italie –, incluant par exemple des cours d’eau à énergie élevée et à chenaux multiples (tresses). La majorité des 28 indicateurs de l’IQM et le guide d’accompagnement (en anglais) sont axés sur ce type d’environnement (Rinaldi et al., 2013, 2015, 2016a, 2016b). Avec l’utilisation de plus en plus fréquente de cet indice par les acteurs de l’eau au Québec, il est nécessaire et pertinent d’adapter l’indice et le guide pour une application optimale dans le contexte du territoire québécois et de ses spécificités physiographiques, hydroclimatiques et écosystémiques. C’est ici qu’intervient le présent guide : il vise donc à outiller et aiguiller (en français) l’utilisateur québécois dans son évaluation de l’IQM

Human-like PB2 627K Influenza Virus Polymerase Activity Is Regulated by Importin-α1 and -α7

Influenza A viruses may cross species barriers and transmit to humans with the potential to cause pandemics. Interplay of human- (PB2 627K) and avian-like (PB2 627E) influenza polymerase complexes with unknown host factors have been postulated to play a key role in interspecies transmission. Here, we have identified human importin-α isoforms (α1 and α7) as positive regulators of human- but not avian-like polymerase activity. Human-like polymerase activity correlated with efficient recruitment of α1 and α7 to viral ribonucleoprotein complexes (vRNPs) without affecting subcellular localization. We also observed that human-like influenza virus growth was impaired in α1 and α7 downregulated human lung cells. Mice lacking α7 were less susceptible to human- but not avian-like influenza virus infection. Thus, α1 and α7 are positive regulators of human-like polymerase activity and pathogenicity beyond their role in nuclear transport

Cyclophilin E Functions as a Negative Regulator to Influenza Virus Replication by Impairing the Formation of the Viral Ribonucleoprotein Complex

The nucleoprotein (NP) of influenza A virus is a multifunctional protein that plays a critical role in the replication and transcription of the viral genome. Therefore, examining host factors that interact with NP may shed light on the mechanism of host restriction barriers and the tissue tropism of influenza A virus. Here, Cyclophilin E (CypE), a member of the peptidyl-propyl cis-trans isomerase (PPIase) family, was found to bind to NP and inhibit viral replication and transcription.In the present study, CypE was found to interact with NP but not with the other components of the viral ribonucleoprotein complex (vRNP): PB1, PB2, and PA. Mutagenesis data revealed that the CypE domain comprised of residues 137–186 is responsible for its binding to NP. Functional analysis results indicated that CypE is a negative regulator in the influenza virus life cycle. Furthermore, knock-down of CypE resulted in increased levels of three types of viral RNA, suggesting that CypE negatively affects viral replication and transcription. Moreover, up-regulation of CypE inhibited the activity of influenza viral polymerase. We determined that the molecular mechanism by which CypE negatively regulates influenza virus replication and transcription is by interfering with NP self-association and the NP-PB1 and NP-PB2 interactions.CypE is a host restriction factor that inhibits the functions of NP, as well as viral replication and transcription, by impairing the formation of the vRNP. The data presented here will help us to better understand the molecular mechanisms of host restriction barriers, host adaptation, and tissue tropism of influenza A virus

Diversification of importin-α isoforms in cellular trafficking and disease states.

The human genome encodes seven isoforms of importin α which are grouped into three subfamilies known as α1, α2 and α3. All isoforms share a fundamentally conserved architecture that consists of an N-terminal, autoinhibitory, importin-β-binding (IBB) domain and a C-terminal Arm (Armadillo)-core that associates with nuclear localization signal (NLS) cargoes. Despite striking similarity in amino acid sequence and 3D structure, importin-α isoforms display remarkable substrate specificity in vivo. In the present review, we look at key differences among importin-α isoforms and provide a comprehensive inventory of known viral and cellular cargoes that have been shown to associate preferentially with specific isoforms. We illustrate how the diversification of the adaptor importin α into seven isoforms expands the dynamic range and regulatory control of nucleocytoplasmic transport, offering unexpected opportunities for pharmacological intervention. The emerging view of importin α is that of a key signalling molecule, with isoforms that confer preferential nuclear entry and spatiotemporal specificity on viral and cellular cargoes directly linked to human diseases

Mutations in Polymerase Genes Enhanced the Virulence of 2009 Pandemic H1N1 Influenza Virus in Mice

Influenza A virus can infect a wide variety of animal species with illness ranging from mild to severe, and is a continual cause for concern. Genetic mutations that occur either naturally or during viral adaptation in a poorly susceptible host are key mechanisms underlying the evolution and virulence of influenza A virus. Here, the variants containing PA-A36T or PB2-H357N observed in the mouse-adapted descendants of 2009 pandemic H1N1 virus (pH1N1), A/Sichuan/1/2009 (SC), were characterized. Both mutations enhanced polymerase activity in mammalian cells. These effects were confirmed using recombinant SC virus containing polymerase genes with wild type (WT) or mutant PA or PB2. The PA-A36T mutant showed enhanced growth property compared to the WT in both human A549 cells and porcine PK15 cells in vitro, without significant effect on viral propagation in murine LA-4 cells and pathogenicity in mice; however, it did enhance the lung virus titer. PB2-H357N variant demonstrated growth ability comparable to the WT in A549 cells, but replicated well in PK15, LA-4 cells and in mice with an enhanced pathogenic phenotype. Despite such mutations are rare in nature, they could be observed in avian H5 and H7 subtype viruses which were currently recognized to pose potential threat to human. Our findings indicated that pH1N1 may adapt well in mammals when acquiring these mutations. Therefore, future molecular epidemiological surveillance should include scrutiny of both markers because of their potential impact on pathogenesis

Credit Supply: Identifying Balance-Sheet Channels with Loan Applications and Granted Loans

To identify credit availability we analyze the extensive and intensive margins of lending with loan applications and all loans granted in Spain. We find that during the period analyzed both worse economic and tighter monetary conditions reduce loan granting, especially to firms or from banks with lower capital or liquidity ratios. Moreover, responding to applications for the same loan, weak banks are less likely to grant the loan. Our results suggest that firms cannot offset the resultant credit restriction by turning to other banks. Importantly the bank-lending channel is notably stronger when we account for unobserved time-varying firm heterogeneity in loan demand and quality

Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease

Background: Experimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. Methods: We conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1β, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. RESULTS: At 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in the 300-mg group than in the placebo group. Canakinumab did not reduce lipid levels from baseline. At a median follow-up of 3.7 years, the incidence rate for the primary end point was 4.50 events per 100 person-years in the placebo group, 4.11 events per 100 person-years in the 50-mg group, 3.86 events per 100 person-years in the 150-mg group, and 3.90 events per 100 person-years in the 300-mg group. The hazard ratios as compared with placebo were as follows: in the 50-mg group, 0.93 (95% confidence interval [CI], 0.80 to 1.07; P = 0.30); in the 150-mg group, 0.85 (95% CI, 0.74 to 0.98; P = 0.021); and in the 300-mg group, 0.86 (95% CI, 0.75 to 0.99; P = 0.031). The 150-mg dose, but not the other doses, met the prespecified multiplicity-adjusted threshold for statistical significance for the primary end point and the secondary end point that additionally included hospitalization for unstable angina that led to urgent revascularization (hazard ratio vs. placebo, 0.83; 95% CI, 0.73 to 0.95; P = 0.005). Canakinumab was associated with a higher incidence of fatal infection than was placebo. There was no significant difference in all-cause mortality (hazard ratio for all canakinumab doses vs. placebo, 0.94; 95% CI, 0.83 to 1.06; P = 0.31). Conclusions: Antiinflammatory therapy targeting the interleukin-1β innate immunity pathway with canakinumab at a dose of 150 mg every 3 months led to a significantly lower rate of recurrent cardiovascular events than placebo, independent of lipid-level lowering. (Funded by Novartis; CANTOS ClinicalTrials.gov number, NCT01327846.

Caractérisation des réseaux de diffraction échelle et leur utilisation en instrumentation astronomique

Titre de l'écran-titre (visionné le 7 août 2023)Le réseau échelle est un élément important de la spectroscopie astronomique du fait de ses caractéristiques qui le différencient des autres réseaux de diffraction tels que sa plus grande résolution spectrale ainsi que sa plus grande dispersion angulaire. Le réseau échelle est donc très utilisé comme élément dispersif dans les spectromètres. De ce fait, il est important que le réseau soit construit avec assez de précision pour que ses performances atteignent celles attendues pour son utilisation. Mon projet porte sur le développement d'un banc de test qui permet de mesurer le pas d'un réseau afin de pouvoir s'assurer de la qualité de sa fabrication. Cette méthode utilise un interféromètre de Fizeau ainsi qu'une platine rotative. La platine rotative permet de trouver la position angulaire d'un ordre précis en configuration Littrow alors que l'interféromètre permet d'apporter des corrections dans les calculs qui permettent une plus grande précision. Ensuite, les données ont été traitées avec des méthodes de calculs à partir des mesures directes ou en passant par une optimisation qui permet d'obtenir des résultats plus précis. Ces méthodes de traitement des données se sont avérées efficaces pour calculer le pas du réseau, quoique celles avec optimisation le sont nettement plus que la méthode directe. Enfin, les corrections obtenues avec l'interféromètre ont eu peu d'impact, sauf pour la correction de l'échelle dans son axe de dispersion.The echelle diffraction grating is a crucial component in astronomical spectroscopy because of its characteristics that differenciate it from other diffraction gratings like its greater spectral resolution and its greater angular dispersion. Echelle grating are often used as the dispersive element in spectrometers. Therefore, making sure the echelle grating's fabrication was with enough precision is important for the echelle to perform at the expected performance for its utilization. My project is about designing a testing bench to measure the grooves length of an echelle grating to characterized the precision of its fabrication. This method used a Fizeau's interferometer and a rotating plate. The rotating plate allows to find the angular position of a specific order in the Littrow configuration while the interferometer allows to perform corrections in the calculation for a better precision. Then, the data will be processed with different methods of calculation which use the measures directly or after those measures has been optimized for more precise results. Those methods appear to be efficient to calculate the grooves density but the method with optimisation is more accurate than the direct method. Finally, the corrections done with the interferometer didn't yield a great impact on the result except for the correction of the echelle in the axis of dispersion

Restoring the conservativity of characteristic-based segregated models: application to the hybrid lattice Boltzmann method

International audienceA general methodology is introduced to build conservative numerical models for fluid simulations based on segregated schemes, where mass, momentum and energy equations are solved by different methods. It is here especially designed for developing new numerical discretizations of the total energy equation, adapted to a thermal coupling with the lattice Boltzmann method (LBM). The proposed methodology is based on a linear equivalence with standard discretizations of the entropy equation, which, as a characteristic variable of the Euler system, allows efficiently decoupling the energy equation with the LBM. To this extent, any LBM scheme is equivalently written under a finite-volume formulation involving fluxes, which are further included in the total energy equation as numerical corrections. The viscous heat production is implicitly considered thanks to the knowledge of the LBM momentum flux. Three models are subsequently derived: a first-order upwind, a Lax-Wendroff and a third-order Godunov-type schemes. They are assessed on standard academic test cases: a Couette flow, entropy spot and vortex convections, a Sod shock tube, several two-dimensional Riemann problems and a shock-vortex interaction. Three key features are then exhibited: 1) the models are conservative by construction, recovering correct jump relations across shock waves, 2) the stability and accuracy of entropy modes can be explicitly controlled, 3) the low dissipation of the LBM for isentropic phenomena is preserved