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Gendered Teacher Feedback, Students' Math Performance and Enrollment Outcomes: A Text Mining Approach
No full textThis paper examines how students’ gender shapes teachers’ feedback and its effects on performance and enrollment. Analyzing written feedback from math teachers to over600,000 French high school students across five years, we find teachers praise girls for effort and positive behavior, while similarly-performing boys are more often criticized forbehavior and praised for intellectual ability. Leveraging quasi-random teacher assignment, we estimate that gendered feedback slightly improves math performance, particularly for girls, especially when effort is emphasized. However, such feedback has no measurable impact on students’ higher education enrollment in the following year
Pa' dentrismo and Pa' fuerismo: reimagining forest governance through Afro-Colombian lens
No full textVie et mort d’un magazine (pas tout-à-fait) comme les autres
No full textInternational audienceEn prônant et assumant une ligne éditoriale qui se démarque de celle des autres titres sportifs de l’époque, Miroir du football incarne également une forme de traitement original de l’information sportive, via son équipe de rédaction. Sous la houlette de François Thébaud, son rédacteur en chef, près de 200 collaborateurs (qu’ils soient spécialistes ou non du football) ont alimenté les rubriques de Miroir en offrant aux lecteurs une approche plus engagée et plus fine des rencontres et du spectacle du football. Cette totale liberté de fonctionnement est toutefois remise en cause dans les années 1970. Les relations conflictuelles entre la direction du journal et François Thébaud aboutissent au départ de ce dernier en 1976. Ce sont moins des divergences idéologiques que des contraintes économiques et commerciales qui sont à l’origine d’une rupture annonçant la disparition du titre en 1979
Power quotients of surface groups and mapping class groups
No full textLet be the fundamental group of a closed, orientable, hyperbolic surface . The -power quotient, , is the quotient of by the th powers of simple closed curves. We prove an analogue of the Dehn--Nielsen--Baer theorem for suitable large values of : the outer automorphism group of is isomorphic to the quotient of the extended mapping class group of by th powers of Dehn twists. There is also a corresponding description of the automorphism group as the quotient of the extended mapping class group of the corresponding once-punctured surface, and we relate these groups via a Birman-type exact sequence. Along the way, and as consequences, we prove structural properties of for suitable large values of , including: is virtually torsion-free, acylindrically hyperbolic, infinitely presented, with solvable word problem and finite asymptotic dimension
A climate of conflict: How the little ice age sparked rebellions and revolutions across Europe
No full textInternational audienceThe Little Ice Age (LIA) – lasting from ∼1250 to ∼1860 - was a long period of cooler, drier conditions, characterized by increased climate instability. The most significant climate extremes were more closely associated with interannual temperature variations or particularly severe, isolated cold spells than with prolonged cold spells lasting many years. During this pre-industrial phase of climate instability, many rebellions broke out, one of the most famous being the French Revolution of 1789. A key question, however, relates to the precise and often intricate role of climate in precipitating these widespread uprisings and rebellions that profoundly reshaped human institutions, particularly in the European context. Using data for solar activity, temperature, precipitation, volcanic forcing and the evolution of grain prices, we compared and contrasted the occurrence of rebellions and revolutions across a wide geographical area comprising Europe-Russia-Ottoman Empire with LIA climate and hazards. We find that climate change primarily affected people's livelihoods by reducing harvests, lowering food-resource availability and sharply increasing cereal prices. Climate therefore played a major role in heightening population vulnerability by exacerbating one of the greatest scourges: malnutrition. For the populace, this fuelled social anger towards political authorities for failing to mitigate the impact of climate change. This study primarily reveals that environmental causes did not generate social crises during the LIA but rather triggered a cascade of environmental and human events that interacted, ultimately leading to highly conflictual situations. The LIA serves as a warning to modern political systems, highlighting the necessity to anticipate the consequences of current climate change to mitigate its impact on societies and prevent social unrest and conflict
A 7000-year record of human influence on Global River Deltas: Geomorphology, stratigraphy, the Anthropocene overprint and future
No full textInternational audienceWith the inception of most of the world’s deltas about 8000 years ago, deltaic floodplains started offering, about a thousand years later, arable land, water and ecosystem services for early human settlements. We identify delta geomorphic changes and proxies and geoarchaeological markers of the human presence on deltas and in their stratigraphy over the last 7000 years, and from ancient maps. We analyse the human-delta relationship in four phases: Neolithic, Metal Ages, Common Era, and Anthropocene, marking increasing human adaptation to changing delta geomorphology modulated by fluctuations in relative sea level and fluvial sediment supply. These adaptations fostered the emergence of urbanization and served as a catalyst for technological innovation and human modification of deltas. The sparse Neolithic human presence in delta stratigraphy gradually expanded to become pervasive in the contemporary Anthropocene, reflecting the twin effects of global population growth and increasingly favourable conditions for humans. We explore the links between early deltaic and non-deltaic communities and gauge the impact of humans on sediment supply from river catchments, and its consequences, notably in terms of frequent delta avulsions, expansion or vulnerability, and explore its inextricable links with climate variation. The Anthropocene is witnessing a profoundly transformed, globally distributed, human-managed delta landscape dominated by important urbanization, reduction in sediment supply, increasing intentional but also unintentional delta modifications, and vulnerability to sea-level rise compounded by exacerbated subsidence. Understanding the human-delta relationship over the past 7000 years contributes to fostering stronger links between geoscience and cultural heritage, to better delta management and sustainability, including an upstream river-basin scale perspective, and to better anticipation of delta futures, notably under the threat of sea-level rise
Intelligent Selection of Spectral Bands from High-Precision Spectroradiometer Measurements for Optimizing Cocoa Bean Classification
No full textInternational audienceEvaluating the spectral properties of cocoa beans based on their fermentation state (fermented, in a poor state, unfermented) is essential for ensuring their quality in the cocoa industry. This study examined the spectral response of beans in the range of 380 nm to 780 nm using the Konica-Minolta CS-2000 spectrophotometer comes from Dijon, France, a device designed to measure the spectrum of objects and sources in the visible range. Different spectral band selection methods have been applied to identify the most discriminating wavelengths for their classification. Several techniques were used: ANOVA, F-score, Lasso, Linear Discriminant Analysis (LDA), Mutual Information, and Partial Least Squares (PLS). A band selector voting process was implemented to determine standard wavelengths identified using the different methods. The selected spectral bands were then leveraged to train classification models, including Random Forest, SVM, and XGBoost. The results show that a restricted subset of wavelengths allows for effective class separation, thereby improving model performance. Among the approaches tested, ANOVA and F-score combined with Random Forest achieved an accuracy of 92.59%, while F-score and Mutual Information coupled with SVM and voting associated with SVM obtained an accuracy of 96.30%. These feature selection methods have effectively reduced dimensionality while maintaining high classification accuracy. These results open up promising prospects for the automation of quality control of cocoa beans, thus contributing to the optimization of industrial processes
Advanced Calibration of Multisystem Hot-Wire Anemometers Using PID Temperature Control and ANN Techniques
No full textInternational audienc
Endomorphisms of Artin groups of type D
No full textInternational audienceWe determine a classification of the endomorphisms of the Artin group A[D-n] of type D-n for n >= 6. In particular we determine its automorphism group and its outer automorphism group. We also determine a classification of the homomorphisms from A[D-n] to the Artin group A[A(n-1)] of type A(n-1) and a classification of the homomorphisms from A[A(n-1)] to A[D-n] for n >= 6. We show that any endomorphism of the quotient A[D-n]/Z(A[D-n]) lifts to an endomorphism of A[D-n] for n >= 4. We deduce a classification of the endomorphisms of A[D-n]/Z(A[D-n]), we determine the automorphism and outer automorphism groups of A[D-n]/Z(A[D-n]), and we show that A[D-n]/Z(A[D-n]) is co-Hopfian for n >= 6. The results are algebraic in nature but the proofs are based on topological arguments (curves on surfaces and mapping class groups)