Des hydro-électriciens face à la variabilité climatique

When making investment or management decisions in the hydroelectricity business, one must often consider the future state of water resources as a random variable. A frequent hypothesis is that of the stationarity of the process : the distribution function of past observations is representative of the distribution function of future observations. Observations of hydrologic regime changes during the twentieth century over various locations lead us to believe that we should consider such phenomena if we are to correctly assess hydrological risk, and that we should reconsider the stationarity hypothesis. Adding to the difficulty of integrating climate variability information into our models are the small samples that we must use to properly evaluate that variability. That problem created a lot of questioning in Québec during the last decade. When we study the annual inflow time series of a number of Québec''s watersheds, particularly in the northeastern part of the Québec-Labrador peninsula, we can identify alternating sequences of high and low inflows. Is the past key to the future ? Should we neglect possible shifts in the series when modelling and forecasting inflows ? Is the long term series average the best predictor for long term expected inflows ? Can we use explanatory variables to explain those changes and help with inflow forecast ? Hydro-Québec has developed and uses many models taking into account those questions. Some models use hidden Markov chains to evaluate regime changes probabilities. Others are depending on climate indices to issue forecasts. Finally, some models combine those approaches. To continue progressing, we now must add larger scale historical information to the models. Using dendrochronology data seems to be the most promising way to improve our models.Résumé : Dans l’élaboration de ses décisions de gestion ou d’investissement, l’hydro-électricien est amené à considérer l’état futur des ressources en eau comme une variable aléatoire. Pour ce faire, on a souvent adopté une approche académique consistant à supposer que la fonction de répartition des observations passées – aux fluctuations d’échantillonnage près – régissait parfaitement les réalisations futures (l’hypothèse de stationnarité). En cas de variabilité climatique, cette démarche entraîne une sous-estimation des probabilités de s’écarter des valeurs communes. Les changements de régime hydrologique observés çà et là sur la planète au XXème siècle montrent qu’il est nécessaire d’envisager de tels phénomènes pour mieux décliner le principe de précaution. Mais l’échantillon local récent étant toujours insuffisant pour apprécier exhaustivement ce type de variabilité, la difficulté est d’intégrer cette variabilité dans nos modèles tout en maîtrisant la subjectivité de l’opération. Ce problème a suscité beaucoup de questionnements et de débats au Québec depuis plus d’une dizaine d’années. En effet, si on examine les chroniques d’apports annuels de certains bassins versants québécois, en particulier pour les bassins versants du nord-est de la péninsule Québec-Labrador, on peut observer en alternance des séquences d''années consécutives de faible et de forte hydraulicité. Le passé est-il garant de l’avenir ? Doit-on négliger la possible présence de ruptures lors de la modélisation et de la prévision des apports en eau ? La moyenne de tout l’historique demeure-t-elle la meilleure prévision de l''apport des années à venir ? Existe-t-il des variables exogènes qui pourraient expliquer ces changements de régimes et qui pourraient être exploitées pour prévoir les apports à venir ? Hydro-Québec a développé et utilise plusieurs modèles proposant des réponses à ces questions. Certains envisagent les probabilités de changement de régime selon une chaîne de Markov cachée. D’autres s’appuient sur des indicateurs climatiques, voire des prévisions météorologiques saisonnières. D’autres, enfin, combinent ces deux approches. L’ajout d’une information historique plus large est aujourd’hui nécessaire pour aller plus loin. La piste la plus prometteuse dans ce sens est l’exploitation des données fournies par la dendrochronologie.Perrault Luc, Garçon Rémy, Gaudet Jocelyn. Des hydro-électriciens face à la variabilité climatique. In: Variations climatiques et hydrologie. Le climat, ses variations séculaires et ses changements pronostiqués : quel impact sur l'hydrologie (ressources en eau et évènements rares, étiages - crues). 29èmes Journées de l'Hydraulique. Congrès de la Société Hydrotechnique de France. Lyon, 27-28 mars 2007. 2007

High‐resolution atmospheric inversion of urban CO2 emissions during the dormant season of the Indianapolis Flux Experiment (INFLUX)

Based on a uniquely dense network of surface towers measuring continuously the atmospheric concentrations of greenhouse gases (GHGs), we developed the first comprehensive monitoring systems of CO2 emissions at high resolution over the city of Indianapolis. The urban inversion evaluated over the 2012–2013 dormant season showed a statistically significant increase of about 20% (from 4.5 to 5.7 MtC ± 0.23 MtC) compared to the Hestia CO2 emission estimate, a state‐of‐the‐art building‐level emission product. Spatial structures in prior emission errors, mostly undetermined, appeared to affect the spatial pattern in the inverse solution and the total carbon budget over the entire area by up to 15%, while the inverse solution remains fairly insensitive to the CO2 boundary inflow and to the different prior emissions (i.e., ODIAC). Preceding the surface emission optimization, we improved the atmospheric simulations using a meteorological data assimilation system also informing our Bayesian inversion system through updated observations error variances. Finally, we estimated the uncertainties associated with undetermined parameters using an ensemble of inversions. The total CO2 emissions based on the ensemble mean and quartiles (5.26–5.91 MtC) were statistically different compared to the prior total emissions (4.1 to 4.5 MtC). Considering the relatively small sensitivity to the different parameters, we conclude that atmospheric inversions are potentially able to constrain the carbon budget of the city, assuming sufficient data to measure the inflow of GHG over the city, but additional information on prior emission error structures are required to determine the spatial structures of urban emissions at high resolution

Preclinical Activity of JNJ-7957, a Novel BCMA ×CD3 Bispecific Antibody for the Treatment of Multiple Myeloma, Is Potentiated by Daratumumab

Purpose: Multiple myeloma (MM) patients with disease refractory to all available drugs have a poor outcome, indicating the need for new agents with novel mechanisms of action. Experimental Design: We evaluated the anti-MM activity of the fully human BCMA_CD3 bispecific antibody JNJ-7957 in cell lines and bone marrow (BM) samples. The impact of several tumorand host-related factors on sensitivity to JNJ-7957 therapy was also evaluated. Results: We show that JNJ-7957 has potent activity against 4 MM cell lines, against tumor cells in 48 of 49 BM samples obtained from MM patients, and in 5 of 6 BM samples obtained from primary plasma cell leukemia patients. JNJ- 7957 activity was significantly enhanced in patients with prior daratumumab treatment, which was partially due to enhanced killing capacity of daratumumab-exposed effector cells. BCMA expression did not affect activity of JNJ-7957. High T-cell frequencies and high effector:target ratios were associated with improved JNJ-7957-mediated lysis of MM cells. The PD-1/ PD-L1 axis had a modest negative impact on JNJ-7957 activity against tumor cells from daratumumab-naïve MM patients. Soluble BCMA impaired the ability of JNJ-7957 to kill MM cells, although higher concentrations were able to overcome this negative effect. Conclusions: JNJ-7957 effectively kills MM cells ex vivo, including those from heavily pretreated MM patients, whereby several components of the immunosuppressive BM microenvironment had only modest effects on its killing capacity. Our findings support the ongoing trial with JNJ-7957 as single agent and provide the preclinical rationale for evaluating JNJ-7957 in combination with daratumumab in MM

Island Visual Artists '86 : An Exhibition Representing the Work of Island Visual Artists

Wyatt stresses the importance of art education in Prince Edward Island. Includes brief statements and biographical notes for 93 artists

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field