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Small amendment arguments: how they work and what they do and do not show
No full textInternational audienceThe small improvement argument has been said to establish that the standard weak preference or value relation can be incomplete. We first show that the argument is one of three possible ‘small amendment arguments’, each of which would yield the same conclusion. Generalizing the analysis thus, we subsequently present a strong and a weak version of small amendment arguments and derive the exact rationality conditions under which they reveal incompleteness. The results show that the arguments (in any of their variants) need not reveal a problem for the possibility of rational choice. In fact, it can be argued that they only reveal such a problem if the underlying relation is complete rather than incomplete
EFFECTIVE MULTIPLIERS FOR WEIGHTS WHOSE LOG ARE HÖLDER CONTINUOUS. APPLICATION TO THE COST OF FAST BOUNDARY CONTROLS FOR THE 1D SCHRÖDINGER EQUATION
No full textWe give a simple proof of the Beurling-Malliavin multiplier theorem (BM1) in the particular case of weights that verify the usual finite logarithmic integral condition and such that their log are Hölder continuous with exponent less than 1. Our proof has the advantage to give an explicit version of BM1, in the sense that one can give precise estimates from below and above for the multiplier, in terms of the exponential type we want to reach, and the constants appearing in the Hölder condition of our weights. The same ideas can be applied to a particular weight, that will lead to an improvement on the estimation of the cost of fast boundary controls for the 1D Schrödinger equation on a segment. Our proof is mainly based on the use of a modified Hilbert transform together with its link with the harmonic extension in the complex upper half plane and some modified conjugate harmonic extension in the upper half plane
Mars Without the Southern Perennial CO 2 Cover
No full textInternational audienceThe Martian South Polar Layered Deposits (SPLD) are composed mostly of ice and dust with a thin perennial CO 2 cover and some internal CO 2 ice layers. In the North, the seasonal CO 2 cap is lost during summer, allowing H 2 O ice to sublimate into the atmosphere. In the South, the perennial CO 2 cover prevents H 2 O ice sublimation. This work uses the Mars Planetary Climate Model to investigate how the H 2 O and CO 2 cycles are affected if the thin perennial CO 2 SPLD cover is lost. We find that during southern summer, the atmospheric water content will more than double in the south polar region. However, on a global scale, the NPLD is still the dominant source of humidity because of its larger surface area. When exposing some of the South Polar Cap buried water ice, the south polar cap becomes the dominant source of atmospheric humidity due to Mars's spin-orbital alignment.</div
(Pro)-Social Learning and Strategic Disclosure
No full textInternational audienceWe study a sequential experimentation model with endogenous feedback. Agents choose between a safe and risky action, the latter generating stochastic rewards. When making this choice, each agent is selfishly motivated (myopic). However, agents can disclose their experiences to a public record, and when doing so are pro-socially motivated (forward-looking). When prior uncertainty is large, disclosure is both polarized (only extreme signals are disclosed) and positively biased (no feedback is bad news). When prior uncertainty is small, a novel form of unraveling occurs and disclosure is complete. Subsidizing disclosure costs can perversely lead to less disclosure but more experimentation
From Pink-Collar to Lab Coat: Cultural Persistence and Diffusion of Socialist Gender Norms
No full textInternational audienceWe study vertical transmission and societal diffusion of gender norms using the large immigration wave from the former Soviet Union (FSU) to Israel in the early 1990’s. Tracking the educational choices of an entire cohort, born in 1988–89, we compare gender gaps among immigrants from the FSU versus natives and immigrants from other countries. We find smaller gender gaps among FSU immigrants in both traditionally male-dominated STEM fields and female-dominated pink collar jobs, e.g., education and social work. These patterns are largely driven by the behavior of FSU women and are not explained by early achievement levels or comparative advantage. Leveraging variation in the concentration of FSU immigrants across middle schools, we find that among natives, gender gaps narrow with the exposure to FSU immigrants, reflecting a shift in the choice patterns of native women towards STEM and away from pink collar fields
Future changes in compound explosive cyclones and atmospheric rivers in the North Atlantic
No full textInternational audienceThe explosive development of extratropical cyclones and atmospheric rivers plays a crucial role in driving extreme weather in the mid-latitudes, such as compound windstorm–flood events. Although both explosive cyclones and atmospheric rivers are well understood and their relationship has been studied previously, there is still a gap in our understanding of how a warmer climate may affect their concurrence. Here, we focus on evaluating the current climatology and assessing changes in the future concurrence between atmospheric rivers and explosive cyclones in the North Atlantic. To accomplish this, we independently detect and track atmospheric rivers and extratropical cyclones and study their concurrence in both ERA5 reanalysis and CMIP6 historical and future climate simulations. In agreement with the literature, atmospheric rivers are more often detected in the vicinity of explosive cyclones than non-explosive cyclones in all datasets, and the atmospheric river intensity increases in all the future scenarios analysed. Furthermore, we find that explosive cyclones associated with atmospheric rivers tend to be longer lasting and deeper than those without. Notably, we identify a significant and systematic future increase in the cyclones and atmospheric river concurrences. Finally, under the high-emission scenario, the explosive cyclone and atmospheric river concurrences show an increase and model agreement over western Europe. As such, our work provides a novel statistical relation between explosive cyclones and atmospheric rivers in CMIP6 climate projections and a characterization of their joint changes in intensity and location
Comprendre les stratégies d’approvisionnement alimentaire des habitants d’un quartier en politique de la ville. Une enquête qualitative conduite Porte de la Chapelle à Paris
No full textInternational audienceWhere do you shop for food when you live in a disadvantaged neighborhood? Few studies analyze where people purchase their foods and factors, which may influence food store choice. This study explores the food purchasing behaviors and strategies of residents living in Porte de la Chapelle (Paris, France), neighborhood with high proportion of deprived population. The aim is to characterize food purchase places of inhabitant to better understand food purchase location choices based on food stores mapping and 25 interviews. The results confirm that food price is a major determinant, leading all respondents to purchase outside their residential neighborhood as foods in food outlets of the neighborhood are too expensive for their budgets (price). But the other dimensions of accessibility are also present in interviews. Participants declare the lack of food outlets in the neighborhood (spatial dimension), not enough diversified (availability) or unsuited to their eating habits (cultural acceptability, for example). Behaviors and representations vary according to individual characteristics, and according to the area of live. Our results therefore show that a policy of food retail diversification should be developed jointly with inhabitants at local level.Où fait-on ses courses alimentaires quand on habite un quartier en politique de la ville ? Rares sont les recherches sur les lieux d’approvisionnement fréquentés et les raisons de ces choix. Cette étude explore les stratégies d’approvisionnement des habitants du quartier Porte de la Chapelle à Paris, marqué par une forte précarité. Elle vise à caractériser les espaces que les habitants fréquentent et parcourent pour s’approvisionner, et à mieux comprendre leurs choix de lieux de courses alimentaires à partir d’une cartographie de l’offre alimentaire et de 25 entretiens. Les résultats confirment que le prix est un déterminant majeur, qui amène les enquêtés à s’approvisionner à l’extérieur du quartier de résidence car les produits disponibles dans les commerces du quartier sont trop chers. Les autres dimensions de l’accessibilité sont également présentes dans les discours. Les participants regrettent le manque de commerces dans le quartier, pas assez diversifiés ou inadaptés à leurs pratiques alimentaires. Les pratiques et les représentations varient en fonction des individus et des secteurs du quartier. Nos résultats invitent donc à construire une politique de diversification des commerces alimentaires avec les habitants des différents secteurs du quartier
ViTAE-SL: A vision transformer-based autoencoder and spatial interpolation learner for field reconstruction
No full textInternational audienceReliable and accurate reconstruction for large-scale and complex physical fields in real-time from limited observations has been a longstanding challenge. In recent years, sensors have been increasingly deployed in numerous physical systems. However, the locations of these sensors can shift over time, such as with mobile sensors, or when sensors are deployed and removed. These sparse and randomly located sensors further exacerbate the difficulty of reconstructing the physical field. In this paper, we present a new deep learning model called Vision Transformer-based Autoencoder (ViTAE) for reconstructing large-scale and complex fields. The proposed network structure is based on a novel core design: vision transformer encoder and Convolutional Neural Network (CNN) decoder. First, we split a two-dimensional field into patches and developed a vision transformer encoder to transfer patches into latent representations. We then reshape the linear latent representations to patches before concatenation, along with a CNN decoder, to reconstruct the field. The proposed model is tested in four different numerical experiments, using generated synthetic data, spatially distributed PM2.5 data, Computational Fluid Dynamics (CFD) simulation data and National Oceanic and Atmospheric Administration (NOAA) sea surface temperature data. The numerical results highlight the strength of ViTAE-SL compared to Kriging and state-of-the-art deep-learning models with significantly higher reconstruction</div