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Simplicial intersection homology revisited
No full textInternational audienceIntersection homology is defined for simplicial, singular and PL chains and it is well known that the three versions are isomorphic for a full filtered simplicial complex. In the literature, the isomorphism, between the singular and the simplicial situations of intersection homology, uses the PL case as an intermediate. Here we show directly that the canonical map between the simplicial and the singular intersection chains complexes is a quasi-isomorphism. This is similar to the classical proof for simplicial complexes, with an argument based on the concept of residual complex and not on skeletons.This parallel between simplicial and singular approaches is also extended to the intersection blown-up cohomology that we introduced in a previous work. In the case of an orientable pseudomanifold, this cohomology owns a Poincaré isomorphism with the intersection homology, for any coefficient ring, thanks to a cap product with a fundamental class. So, the blown-up intersection cohomology of a pseudomanifold can be computed from a triangulation. Finally, we introduce a blown-up intersection cohomology for PL spaces and prove that it is isomorphic to the singular one
CD63, a new therapeutical candidate for cholesterol homeostasis regulation through extracellular vesicles?
No full textInternational audienceCD63 is a tetraspanin initially associated with late endosomes and contributes to numerous functions at the cell level, such as intracellular endosomal and lysosomal trafficking, adhesion, and motility. CD63 also plays a key role in the biogenesis and release of exosomes, i.e., small extracellular vesicles (EVs) of endosomal origin, facilitating the formation of multivesicular bodies (MVBs), the coordination with the endosomal sorting complexes required for transport (ESCRT) machinery, the selection of cargoes carried by future exosomes, and the fusion of MVBs with the plasma membrane for exosome release. In a recent publication in Nature Cell Biology, Guillaume van Niel's team provides arguments in favor of another EV-linked function for CD63, namely the regulation of cholesterol storage and release by small EVs of endogenous origin. Complemented by two other publications from the teams of Keisuke Ito and Xabier Ostreikoetxea, which respectively describe the role of (i) mitochondrial metabolism on CD63 function and (ii) the link between the reduced CD63 + small EVs and dyslipidemia, these arguments highlight the key role of CD63 in the regulation of cholesterol homeostasis through exosomes and more widely small EVs in physiological and pathological conditions. Future research on CD63 may thus redefine our approach to cellular lipid management and therapeutic lipid delivery.</div
Efficient parametric estimation of the spatial autoregressive model
No full textThis paper introduces a new one-step parametric estimation method for spatial autoregressive (SAR) models, providing an efficient estimator for any error distribution with a defined quantile function. Based on Le Cam's Local Asymptotic Normality (LAN) theory, it extends the maximum likelihood approach to cases like the Laplace distribution, which lacks a globally defined first derivative.\We further develop this estimator for two highly flexible distributions: Tukey's gand-h and Pewsey and Jones's sinh-arcsinh (SAS), designed to capture skewness and non-normal tail weight. These flexible distributions mitigate the risks of distributional misspecification by approximating a wide range of parametric distributions. Monte Carlo simulations assess finite-sample performance, showing that our estimator outperforms traditional parametric spatial methods when the error distribution deviates from normality and is well-approximated by these flexible alternatives
Cannabis growers as gardeners: results from a survey among Italian and British small-scale growers
No full textInternational audienceBackgroundThe horticultural nature of growing cannabis is often overlooked in the study of cannabis production, and subsequent policies. Little is known about whether growers' horticultural expertise influences cannabis cultivation methods, the growing of other psychoactive plants, substance use behaviors, or interactions with the criminal justice system. The trajectory of cultivation, in terms of whether cannabis is a gateway to more general gardening, or vice versa, is also unexplored. Studying individuals who combine cannabis cultivation with other gardening activities is valuable because it provides insights into the motivations and practices of cannabis growers as illegal drug market participants.MethodsData from 1302 small-scale cannabis growers in Italy and the UK was collected through an online survey from 2020 to 2021. We ran two regressions to compare (1) those who only grow cannabis with those who also grow other plants and; (2) those who started growing cannabis and then grew other plants and vice versa.ResultsMost people in our sample grew cannabis and other plants (General Gardeners; 82 %). In comparison with the Only-cannabis group (OCG), General Gardeners (GG) tended to be older, more educated, and more likely to be in a relationship. GG grew more cannabis crops outdoors, and the purposes for growing were more related to ecological or medical reasons rather than selling cannabis. The OCG group had higher odds of using stimulant drugs and meeting cannabis use dependence criteria compared to GG. Among GG, the majority (71 %) started growing other plants and later moved to cannabis.ConclusionGardening other plants is common among cannabis growers and precedes cultivating cannabis far more than the reverse pathway. As general gardeners appear focused on cannabis alone, concerns about spillover to growing other psychoactive plants or fungi may be overstated. Given the lower expected harms associated with general gardening, it could serve as a proxy for reduced supply involvement in legal assessments
Outils linguistiques pour exprimer l’humour en coréen - en lien avec les néologismes récents
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Complex magnetic properties of the double perovskite Hg 2 MnTeO 6 probed by thermodynamic measurements and neutron diffraction
No full textInternational audienceWe studied the structural and magnetic properties of the double perovskite oxides containing mercury, A 2 MnTeO 6 (A = Hg, Hg 0.8 Ca 0.2 , and Ca). Hg 2 MnTeO 6 and (Hg 0.8 Ca 0.2 ) 2 MnTeO 6 crystallize in a rhombohedral phase with R3 space group, while Ca 2 MnTeO 6 crystallizes in a monoclinic phase with P2 1 /n space group. The magnetic susceptibility, specific heat, and neutron diffraction measurements show that, upon cooling, the commensurate antiferromagnetic (AFM) order occurs at 10 K, 8 K, and 11 K for A = Hg, Hg 0.8 Ca 0.2 , and Ca systems, respectively. The first-principles calculations agree well with the experimental results, showing that the type-I AFM spin arrangement, i.e., magnetic moments aligned ferromagnetically within the planes and antiferromagnetically between adjacent planes, has the lowest total energy compared to other types of long-range order. For all three systems, the magnetic entropy associated with the AFM order amounts to less than 80% of the theoretical value for the high-spin state of Mn 2+ , indicating magnetic frustration across the series. Additionally, an incommensurate order at 5 K was identified by neutron diffraction for Hg 2 MnTeO 6 , which can be described by helicoidal spin order. This observation makes Hg 2 MnTeO 6 one of the most complex magnetic systems among double perovskite oxides
From ferrimagnetism to spin-glass behavior in alkali- and rare-earth metal crichtonites
No full textInternational audienceIn this work, nine new synthetic alkali- and rare-earth metal crichtonite-type compounds with AB3C18O38 general formula are presented. The effect on the magnetic properties as consequence of the substitution of divalent and trivalent cations in the A site, as well as the introduction of iron at the B and C sites is studied. Ferrimagnetic behavior was identified in the crichtonites CaMn3Ti18O38, BaMn3Ti18O38 and CaFe3Ti18O38, which changes to a spin-glass type for the BaMn3Ti14Fe4O38 and A-trivalent REMn3Ti18O38 (RE = La, Ce and Nd), LaFe3Ti18O38 and LaMn3Ti13Fe5O38. A comprehensive comparison of the AC and DC magnetic measurements for whole series along with the FiM structure obtained by neutron powder diffraction is discussed. These results will expand the comprehension on this almost unexplored magnetic family of compounds
Operations & Supply Chain Management: Principles and Practice
No full textInternational audienceOperations and Supply Chain Management (OSCM) has continually evolved, incorporating a broad array of strategies, frameworks, and technologies to address complex challenges across industries. This encyclopedic article provides a comprehensive overview of contemporary strategies, tools, methods, principles, and best practices that define the field’s cutting-edge advancements. It also explores the diverse environments where OSCM principles have been effectively implemented. The article is meant to be read in a nonlinear fashion. It should be used as a point of reference or first-port-of-call for a diverse pool of readers: academics, researchers, students, and practitioners
Breaking organizational paths for strategic renewal: Towards a dialectical perspective
No full textInternational audienceStrategic renewal is key to organizations' long-term success, but may be difficult to achieve if they are locked into a particular action path. Unfortunately, breaking organizational paths remains somewhat elusive due to a binary opposition in the strategic renewal literature between path breaking and path dependence, which hampers more complex process theorization. Asking what roles path breaking and path dependence exactly play in strategic renewal, we perform an in-depth case study of path-breaking interventions at fashion retailer Kiabi. This firm gradually moved from a path of disintegrative to integrative collaborative alignment between departments, whereby adaptive expectations regarding others’ willingness to collaborate gradually improved. Chiefly, we find that strategic renewal is a function of two concurrent dialectics: 1) between path-breaking interventions and relapses into old path-dependent tendencies; and 2) between initiatives by upper management and their firm-wide implementation. We contribute to the literature by demonstrating that organizational path dependence, through managerial reflection and action, can be integral to path breaking, and, more broadly, strategic renewal. Furthermore, we extend common notions of managerial agency in path breaking by highlighting the involvement of various hierarchical layers, while, paradoxically, we relax the strong assumption of managerial agency that exists in studies on open strategy
Assessing Market Quality and Price Impact: Executing a Portfolio Manager’s Investment Decisions
No full textThe Case Centre, case study 125-0078-1, teaching note 125-0078-8, teaching note supplement 125-0078-8BThis case study presents a dynamic, hands-on trading simulation where students step into the role of junior traders at Q-Cumber Capital, a fictional investment firm. Tasked with assisting a Senior Portfolio Manager (represented by the instructor), students are challenged to refine execution strategies and provide data-driven insights on market quality and trade timing. Previously, junior traders at the firm helped assess market conditions by analyzing limit order book snapshots to compute liquidity proxies before trade execution. However, a recent shift at Q-Cumber Capital has restricted the Portfolio Manager's access to real-time limit order books. Now, students must rely on historical trade-and-quote (TAQ) data to evaluate ex-post market quality, measuring the impact of large orders on price movements and liquidity conditions. The case places students in a realistic trading environment where they must not only conduct financial computations but also synthesize data to form actionable recommendations. It strengthens technical competencies such as market microstructure analysis, advanced Excel modeling, and data visualization, while also sharpening decision-making skills in a high-frequency trading context. By bridging theoretical concepts with applied learning, the case enhances students' ability to navigate execution challenges in financial markets