Collège de Bois-de-Boulogne

ABSTRACT In this paper we complete the presentation of a new hybrid 2 × 2D flux transport dynamo (FTD) model of the solar cycle based on the Babcock–Leighton mechanism of poloidal magnetic field regeneration via the surface decay of bipolar magnetic regions (BMRs). This hybrid model is constructed by allowing the surface flux transport (SFT) simulation described in Lemerle et al. to provide the poloidal source term to an axisymmetric FTD simulation defined in a meridional plane, which in turn generates the BMRs required by the SFT. A key aspect of this coupling is the definition of an emergence function describing the probability of BMR emergence as a function of the spatial distribution of the internal axisymmetric magnetic field. We use a genetic algorithm to calibrate this function, together with other model parameters, against observed cycle 21 emergence data. We present a reference dynamo solution reproducing many solar cycle characteristics, including good hemispheric coupling, phase relationship between the surface dipole and the BMR-generating internal field, and correlation between dipole strength at cycle maximum and peak amplitude of the next cycle. The saturation of the cycle amplitude takes place through the quenching of the BMR tilt as a function of the internal field. The observed statistical scatter about the mean BMR tilt, built into the model, acts as a source of stochasticity which dominates amplitude fluctuations. The model thus can produce Dalton-like epochs of strongly suppressed cycle amplitude lasting a few cycles and can even shut off entirely following an unfavorable sequence of emergence events.

Abstract The dynamic activity of stars such as the Sun influences (exo)planetary space environments through modulation of stellar radiation, plasma wind, particle and magnetic fluxes. Energetic solar-stellar phenomena such as flares and coronal mass ejections act as transient perturbations giving rise to hazardous space weather. Magnetic fields – the primary driver of solar-stellar activity – are created via a magnetohydrodynamic dynamo mechanism within stellar convection zones. The dynamo mechanism in our host star – the Sun – is manifest in the cyclic appearance of magnetized sunspots on the solar surface. While sunspots have been directly observed for over four centuries, and theories of the origin of solar-stellar magnetism have been explored for over half a century, the inability to converge on the exact mechanism(s) governing cycle to cycle fluctuations and inconsistent predictions for the strength of future sunspot cycles have been challenging for models of the solar cycles. This review discusses observational constraints on the solar magnetic cycle with a focus on those relevant for cycle forecasting, elucidates recent physical insights which aid in understanding solar cycle variability, and presents advances in solar cycle predictions achieved via data-driven, physics-based models. The most successful prediction approaches support the Babcock-Leighton solar dynamo mechanism as the primary driver of solar cycle variability and reinforce the flux transport paradigm as a useful tool for modelling solar-stellar magnetism.

The need for reliable predictions of the solar activity cycle motivates the development of dynamo models incorporating a representation of surface processes sufficiently detailed to allow assimilation of magnetographic data. In this series of papers we present one such dynamo model, and document its behavior and properties. This first paper focuses on one of the model's key components, namely surface magnetic flux evolution. Using a genetic algorithm, we obtain best-fit parameters of the transport model by least-squares minimization of the differences between the associated synthetic synoptic magnetogram and real magnetographic data for activity cycle 21. Our fitting procedure also returns Monte Carlo-like error estimates. We show that the range of acceptable surface meridional flow profiles is in good agreement with Doppler measurements, even though the latter are not used in the fitting process. Using a synthetic database of bipolar magnetic region (BMR) emergences reproducing the statistical properties of observed emergences, we also ascertain the sensitivity of global cycle properties, such as the strength of the dipole moment and timing of polarity reversal, to distinct realizations of BMR emergence, and on this basis argue that this stochasticity represents a primary source of uncertainty for predicting solar cycle characteristics.

Abstract The polar precursor method is widely considered to be the most robust physically motivated method to predict the amplitude of an upcoming solar cycle. It uses indicators of the magnetic field concentrated near the poles around the sunspot minimum. Here, we present an extensive analysis of the performance of various such predictors, based on both observational data (Wilcox Solar Observatory (WSO) magnetograms, Mount Wilson Observatory polar faculae counts, and Pulkovo A(t) index) and outputs (polar cap magnetic flux and global dipole moment) of various existing flux transport dynamo models. We calculate Pearson correlation coefficients (r) of the predictors with the next cycle amplitude as a function of time measured from several solar cycle landmarks: setting r = 0.8 as a lower limit for acceptable predictions, we find that observations and models alike indicate that the earliest time when the polar predictor can be safely used is 4 yr after the polar field reversal. This is typically 2–3 yr before the solar minimum and about 7 yr before the predicted maximum, considerably extending the usual temporal scope of the polar precursor method. Reevaluating the predictors another 3 yr later, at the time of the solar minimum, further increases the correlation level to r ≳ 0.9. As an illustration of the result, we determine the predicted amplitude of Cycle 25 based on the value of the WSO polar field at the now official minimum date of 2019 December as 126 ± 3. A forecast based on the value in early 2017, 4 yr after the polar reversal would have only differed from this final prediction by 3.1 ± 14.7%.

Abstract The composition of vinyl acetate–butyl acrylate copolymers obtained with batch emulsion polymerization have been studied by 1H‐NMR. Using the integrated copolymerization Meyer–Lowry equation, the apparent reactivity ratios of the two monomers were calculated as 10.67 for r1, the reactivity ratio of butyl acrylate (BA), and 0.024 for r2, the reactivity ratio of vinyl acetate (VAC). These results were compared with those obtained by other methods.

Context. Two candidate mechanisms have recently been considered with regard to the nonlinear modulation of solar cycle amplitudes. Tilt quenching (TQ) comprises the negative feedback between the cycle amplitude and the mean tilt angle of bipolar active regions relative to the azimuthal direction. Latitude quenching (LQ) consists of a positive correlation between the cycle amplitude and average emergence latitude of active regions. Aims. Here, we explore the relative importance and the determining factors behind the LQ and TQ effects. Methods. We systematically probed the degree of nonlinearity induced by TQ and LQ, as well as a combination of both using a grid based on surface flux transport (SFT) models. The roles played by TQ and LQ are also explored in the successful 2×2D dynamo model, which has been optimized to reproduce the statistical behaviour of real solar cycles. Results. The relative importance of LQ versus TQ is found to correlate with the ratio u 0 / η in the SFT model grid, where u 0 is the meridional flow amplitude and η is the diffusivity. An analytical interpretation of this result is given, further demonstrating that the main underlying parameter is the dynamo effectivity range, λ R , which is, in turn, determined by the ratio of equatorial flow divergence to diffusivity. The relative importance of LQ versus TQ is shown to scale as $ C_1+C_2/\lambda_R^2 $. The presence of a latitude quenching effect is seen in the 2×2D dynamo, contributing to the nonlinear modulation by an amount that is comparable to TQ. For other dynamo and SFT models considered in the literature, the contribution of LQ to the modulation covers a broad range – from entirely insignificant to serving as a dominant source of feedback. On the other hand, the contribution of a TQ effect (with the usually assumed amplitude) is never shown to be negligible.

To date, the only curative treatment for high-risk or refractory hematologic malignancies non-responsive to standard chemotherapy is allogeneic hematopoietic transplantation (allo-HCT). Acute graft-versus-host disease (GVHD) is a donor T cell-mediated immunological disorder that is frequently fatal and the leading cause of non-relapse mortality (NRM) in patients post allo-HCT. The pathogenesis of acute GVHD involves recognition of minor and/or major HLA mismatched host antigens by donor T cells followed by expansion, migration and finally end-organ damage due to combination of inflammatory cytokine secretion and direct cytotoxic effects. The endothelium is a thin layer of endothelial cells (EC) that line the innermost portion of the blood vessels and a key regulator in vascular homeostasis and inflammatory responses. Endothelial cells are activated by a wide range of inflammatory mediators including bacterial products, contents released from dying/apoptotic cells and cytokines and respond by secreting cytokines/chemokines that facilitate the recruitment of innate and adaptive immune cells to the site of inflammation. Endothelial cells can also be damaged prior to transplant as well as by alloreactive donor T cells. Prolonged EC activation results in dysfunction that plays a role in multiple post-transplant complications including but not limited to veno-occlusive disease (VOD), transplant associated thrombotic microangiopathy (TA-TMA), and idiopathic pneumonia syndrome. In this mini review, we summarize the biology of endothelial cells, factors regulating EC activation and the role of ECs in inflammation and GVHD pathogenesis.

We examine the impact of surface inflows into activity belts on the operation of solar cycle models based on the Babcock–Leighton mechanism of poloidal field regeneration. Towards this end we introduce in the solar cycle model of Lemerle & Charbonneau (2017.ApJ834: 133) a magnetic flux-dependent variation of the surface meridional flow based on the axisymmetric inflow parameterization developped by Jiang et al. (2010.ApJ717: 597). The inflow dependence on emerging magnetic flux thus introduces abona fidenonlinear backreaction mechanism in the dynamo loop. For solar-like inflow speeds, our simulation results indicate a decrease of 10–20% in the strength of the global dipole building up at the end of an activity cycle, in agreement with earlier simulations based on linear surface flux transport models. Our simulations also indicate a significant stabilizing effect on cycle characteristics, in that individual cycle amplitudes in simulations including inflows show less scatter about their mean than in the absence of inflows. Our simulations also demonstrate an enhancement of cross-hemispheric coupling, leading to a significant decrease in hemispheric cycle amplitude asymmetries and temporal lag in hemispheric cycle onset. Analysis of temporally extended simulations also indicate that the presence of inflows increases the probability of cycle shutdown following an unfavorable sequence of emergence events. This results ultimately from the lower threshold nonlinearity built into our solar cycle model, and presumably operating in the sun as well.

The second fossil Ceratocombidae Leptonannus miocenicus n. sp. is described as first extinct representative of the genus, from the Middle Miocene Mexican amber. The species is distinguished from its related taxa, a discussion is given.

An algebraic method for the reconstruction and potentially prediction of the solar dipole moment value at sunspot minimum (known to be a good predictor of the amplitude of the next solar cycle) was suggested in the first paper in this series. The method sums up the ultimate dipole moment contributions of individual active regions in a solar cycle: for this, detailed and reliable input data would in principle be needed for thousands of active regions in a solar cycle. To reduce the need for detailed input data, here we propose a new active region descriptor called ARDoR (Active Region Degree of Rogueness). In a detailed statistical analysis of a large number of activity cycles simulated with the 2 × 2D dynamo model we demonstrate that ranking active regions by decreasing ARDoR, for a good reproduction of the solar dipole moment at the end of the cycle it is sufficient to consider the top N regions on this list explicitly, where N is a relatively low number, while for the other regions the ARDoR value may be set to zero. For example, with N = 5 the fraction of cycles where the dipole moment is reproduced with an error exceeding ±30% is only 12%, significantly reduced with respect to the case N = 0, i.e. ARDoR set to zero for all active regions, where this fraction is 26%. This indicates that stochastic effects on the intercycle variations of solar activity are dominated by the effect of a low number of large “rogue” active regions, rather than the combined effect of numerous small ARs. The method has a potential for future use in solar cycle prediction.

Cette étude a été réalisée auprès de 12 208 cégépiens du régulier, inscrits à la session d’automne 2014 et provenant de huit cégeps situés dans différentes régions du Québec. Elle mesure l’ampleur des besoins socioaffectifs des répondants et l’utilisation des services d’aide qui leur sont offerts. Les résultats indiquent que les trois quarts des répondants ont recours à de tels services d’aide pour des problèmes autres que scolaires. Les principaux motifs de ce recours sont la satisfaction, la curiosité et la souffrance. Les résultats montrent aussi que 17,4 % des répondants ont ressenti beaucoup ou énormément de détresse et que 35,1 % ont éprouvé souvent ou tout le temps de l’anxiété. Les principaux facteurs explicatifs de la détresse et de l’anxiété sont les conflits familiaux, la pression liée au rendement scolaire, l’intimidation et les pensées suicidaires. Ainsi, 29,3 % disent qu’ils ont vécu beaucoup ou énormément de détresse à l’égard des conflits familiaux; 33,3 % ont éprouvé beaucoup ou énormément de pression liée à la performance scolaire; 11,9 % ont ressenti beaucoup ou énormément de détresse liée à l’intimidation et 18,3 % des répondants affirment avoir eu des pensées suicidaires et parmi eux, 7,3 % disent en avoir eues souvent ou tout le temps. Enfin, certains préjugés à l’égard de la santé mentale apparaissent comme un frein significatif à l’utilisation des ressources d’aide.

This article focuses on the attitude of practicing teachers toward teaching science and technology (S&T). It reports the results of a study conducted with 110 late-elementary school teachers in order to assess their attitude at the end of a particular training intervention. The intervention was based on pairing teachers with pre-university science students (aged 17–19). In the experimental group, all 42 teachers were accompanied by a pre-university student in their classroom to conduct activities on topics included in the intervention. We used a mixed-method approach, combining pretest, posttest, and interviews. The interaction effect of factorial ANOVAs was significant for the subconstructs of self-efficacy, context-dependency, and behavioral intention to teach specific S&T concepts. The interviews suggest that the presence of pre-university students in the classroom had a beneficial effect on teachers’ attitude.

Une première partie de ce texte a présenté une nouvelle théorie de la psyché. Cette nouvelle théorie, dans la mesure où elle remet au travail le processus mémoriel, nous introduit, au plan de la méthode analytique, au nouveau paradigme de la transitionnalité en complémentarité avec le paradigme plus classique de la remémoration. Chemin faisant, nous posons un nouveau regard sur le transfert et l’interprétation.

Cet article s’intéresse aux initiatives citoyennes qui prennent place dans le contexte des désappropriations associées à la mondialisation économique néolibérale et de la redéfinition du rapport au politique des citoyens. À partir de l’exemple des Initiatives de transition et plus précisément du cas de Villeray en transition (VET), les auteurs explorent le cadre théorique des Initiatives citoyennes d’appropriation de l’espace habité (ICAEH) ainsi que les dimensions sociales, symboliques et matérielles de cette dernière. Ces nouvelles formes d’initiatives se réalisent dans un rapport au politique caractérisé par une logique ascendante (en termes de participation citoyenne), une démarche réflexive, horizontale et conscientisante d’empowerment entre citoyens. C’est la volonté de créer un « meilleur quartier sans pétrole » dans une perspective optimiste et de développer un « art de vivre local » qui amène les citoyens comme ceux de VET à repenser leurs pratiques sociales de voisinage et à tisser des réseaux inclusifs au sein de Villeray. En s’appropriant symboliquement et socialement l’espace habité, les citoyens transforment progressivement les pratiques matérielles de leur quartier.

L'accucil d'un enfant atteint d'une déficience provoque chez les parents un stress psychologique intense et ceux-ci sont alors confrontés à une situation de crise. C'est par le cheminement à travers le processus de deuil de l'enfant désiré «parfait» que les parents parviennent à s'adapter à la situation, plusieurs auteurs ont décrit une séquence de réactions normales par laquelle doivent passer les parents qui donnent naissance à un enfant atteint d'une déficience. Cette situation difficile affecte les parents dans les différentes sphegres d'adaptation, c'est-à-dire en tant qu'individu, conjoint, parent et en relation avec l'entourage. Des difficultés d'adaptation, qui ne sont pas nécessairement reliées à la gravité du probléme, sont susceptibles de se manifester chez les parents et la famille entière. De méme, la facon de réagir de chacun des membres aura un impact sur tout le système familial.

INTRODUCTION: Patients with inflammatory bowel disease (IBD) are at higher risk of thromboembolic events (TE). In pediatric-onset IBD, more data on incidence and risk factors of venous (VTE) and arterial events (ATE) at the population level are needed to guide thromboprophylaxis. METHODS: All patients aged ≤ 16 years diagnosed with Crohn's disease (CD) or ulcerative colitis (UC) between 1988 and 2011 in the prospective EPIMAD population-based registry were followed until 2013. Every TE occurring during the follow-up period was included. RESULTS: A total of 1,344 patients were included: 1,007 with CD and 337 with UC, and a median diagnosis age of 14.3 years. After a median follow-up of 8.3 years, 2 (0.15 %) ATE and 15 (1.1 %) VTE occurred at median age of 20.4 years. The global incidence rate of thromboembolic events was 1.32 per 1000 person-years. Periods of active disease (HR=8.4, p = 0.0002), the 3-month-period following surgery (HR=16.4, p = 0.0002) and hospitalization (HR=21.7, p < 0.0001) were found to be associated with an increased risk of VTE. A lower rate of VTE was found in patients treated with 5-aminosalicylates (HR=0.1, p = 0.002). CONCLUSION: The risk of TE was low in this population. VTE were strongly associated with active disease, surgery and hospitalization.

The objective of this study is to take the initial steps toward developing novel antibiotics to counteract the escalating problem of antimicrobial and bacterial persistence, particularly in relation to biofilms. Our approach involves emulating the structural characteristics of cationic antimicrobial peptides. To circumvent resistance development, we have designed a library of bis-benzimidazolium salts that selectively target the microbial membranes in a nonspecific manner. To explore their structure–activity relationship, we conducted experiments using these compounds on various pathogens known for their resistance to conventional antibiotics, including Gram-positive methicillin - resistant Staphylococcus aureus ( MRSA ), vancomycin - resistant Enterococcus faecium ( VRE ), and Gram-negative Escherichia coli ( E. coli ). Notably, two bis-benzimidazolium salts exhibited robust antimicrobial activity while maintaining a high level of selectivity compared with mammalian cells. Our investigations revealed significant antibiofilm activity, as these compounds rapidly acted against established biofilms. In addition, bis-benzimidazolium compounds exhibited consistent results in resistance development and cross-resistance studies. Consequently, amphiphilic bis-benzimidazolium salts hold promise as potential candidates to combat resistance-associated infections.

Typical object-oriented (OO) systems implement several functional features that are interwoven into class hierarchies. In the absence of aspect-oriented techniques to develop and compose these features, developers resort to object-oriented design and programming idioms to separate features as well as possible. Given a legacy OO system, discovering existing functional features helps understand the design of the system and extract these features to ease their maintenance and reuse. We want to discover candidate functional features in OO systems. We first define functional features and then discuss the footprints that such features are likely to leave in an OO system. We identify three such footprints: (1) multiple inheritance, (2) delegation, and (3) ad-hoc. We develop a set of algorithms for identifying such footprints in OO code and implemented them for the Java language using Eclipse JDT. In this article, we present the algorithms, and the results of applying the corresponding tools on five open-source systems: FreeMind, JavaWebMail, JHotDraw, JReversePro, and Lucene. Our experimental results show that: (1) the different algorithms can identify interesting and useful candidate functional features in OO systems, (2) they can identify opportunities for refactoring, and (3) they are complementary and could help developers.

Résumé En français, les constructions transitives indirectes présentent des difficultés d’analyse dont font mention les descriptions linguistiques actuelles aussi bien que les grammaires traditionnelles. Dans un premier temps, nous proposons un résumé des difficultés que soulèvent les analyses traditionnelles. Le principal obstacle dans la distinction entre le complément d’objet indirect et le complément circonstanciel réside dans la nature des tests d’analyse qui ne se distinguent guère à ce niveau. Des phrases comme Mathieu va au stade (= un complément d’objet indirect) et Mathieu s’entraîne au stade (= un complément circonstanciel) ne peuvent se différencier de la manière traditionnelle. C’est ainsi que, dans un second temps, nous aboutissons, par l’examen de l’application de tests comme la pronominalisation et l’effacement, à l’évaluation de la pertinence de la notion de complément essentiel pour obtenir des analyses probantes. Des statistiques complètent cet article sur des emplois de plus de dix mille verbes et des principales prépositions introduisant un complément d’objet indirect.

This paper is a first empirical foray in the debate concerning mandatory bilingualism for Supreme Court judges in Canada. The paper summarizes the main arguments, discusses the framing of bilingualism as a “legal” or an “identity” requirement, and uses empirical data to assess whether unilingualism has had an impact on four dimensions of the decision-making process at the Supreme Court of Canada: panel composition, assertiveness, individual caseloads and deference towards lower courts by unilingual and bilingual judges. Our results suggest that there is a correlation between the fluency in French and the first three elements but that there is no difference in the level of deference across linguistic groups towards francophone lower courts. Even if the paper is exploratory in nature and warrants further research, the general picture that emerges is that language proficiency superimposes itself as another kind of legal specialization in the inner-working of the Court.