Science & Mathematics

Atomically thin two-dimensional (2D) materials have been-and are still currently beingextensively studied due to their unique mechanical, electrical, and optical properties, which, together with their ultra-thin size, enable the development of compact devices and innovative technologies. Within the vast chemical space of transition metal dichalcogenides (TMDs), single-layer molybdenum disulphide (MoS2) is with no doubt one of the most studied material due to its stability and its direct optical band gap of 1.8 eV, which make it the ideal candidate to be used in a wide range of nanoelectronic devices, going beyond conventional CMOS technology. Here we look at MoS2 in the context of biosensing, and we study such material as the core component of field-effect biosensors (Bio-FETs) for the detection of cortisol. Ultimately, the aim of this study is to design and integrate such biosensors in wearable health monitoring devices. We want to bridge the gap between materials' properties and device physics and to do so, we carry out first-principles atomistic computer simulations in the framework of density functional theory (DFT). Our study constitutes the first step of a wider multi-scale modelling approach in which the goal is to construct a full atomistic-to-device level model. Recently, MoS2 has been studied as a sensing platform for detecting mainly gas and small biological molecules, such as glucose. [3] Enzymatic biosensing is the most common approach, however, non-enzymatic sensing can provide higher sensor stability and prompt response at the expense of chemical selectivity. Here, we are interested in the non-enzymatic detection of cortisol in human sweat as a mean to monitor the risk of cardiovascular diseases. However, the mechanisms that govern the interaction between the analyte and MoS2 at the molecular level are far from being understood. Thus, we thoroughly explore the MoS2/cortisol interaction in terms of both structural, electronic, and charge transfer properties to assess viable sensing mechanisms. We study the impact of some of the most used metal dopants employed in lab-scale experiments, such as Ni, Pt, Pd, in order to modulate the sensing platform with respect to bare MoS2. In addition to single-atom doping, we also explore the use of metal nanoparticles (e.g., Pt and Au) to decorate the MoS2 layer as yet another mean to detect cortisol. Overall, our work ultimately aims to obtain a deep understanding of the properties of MoS2 when used as a sensor to drive the design of devices towards better performance.

Frequent zoonotic transmission of hepatitis E virus (HEV) has been suspected, but data supporting the animal origin of autochthonous cases are still sparse. We assessed the genetic identity of HEV strains found in humans and swine during an 18-month period in France. HEV sequences identified in patients with autochthonous hepatitis E infection (n = 106) were compared with sequences amplified from swine livers collected in slaughterhouses (n = 43). Phylogenetic analysis showed the same proportions of subtypes 3f (73.8%), 3c (13.4%), and 3e (4.7%) in human and swine populations. Furthermore, similarity of >99% was found between HEV sequences of human and swine origins. These results indicate that consumption of some pork products, such as raw liver, is a major source of exposure for autochthonous HEV infection.

Indigenous mapping is a powerful political tool for long‐marginalized populations to create visibility and establish land claims. In the case of Argentina, a country that was built on a denial of the presence of Indigenous peoples in the national territory, the emergence of these maps stemming from participatory processes coincided with the recognition of these communities' territorial rights in 1994. However, this mapping of Indigenous territories freezes extremely dynamic and complex socio‐spatial realities just as it inflects their representations. In this paper, I reassess the weight and the role that Indigenous cartographic representations play in the evolution of these populations' spatial capital. Paradoxically, they give rise to more contradictions than they clarify. These paradoxes demonstrate the varied relationships different generations maintain with their territory, just as they concern its structure and its cartographic form. Therefore, based on the case of the Wichí of the Argentinian Chaco, this paper contributes to the understanding of contemporary issues of indigeneity by adopting a critical approach to Indigenous cartography. Whereas in Argentina cartographic knowledge is undergoing a process of decolonization, this does not apply to the legal system or to society as a whole.

Although a variety of specialised formalisms have been proposed specifically for enterprise modelling, the use of existing modelling languages has not received as much attention. In this paper, we demonstrate that the systems modelling formalism SysML is in fact not sufficient to act as a standalone language for enterprise modelling. To demonstrate this claim, we show that there are four key enterprise modelling scenarios that cannot be addressed while adhering to SysML semantics: temporal representation, timing and scheduling, collaborations between two or more teams and decision trees .

Les superalliages durcis par la phase γ' sont utilisés dans les moteurs des avions civils nouvelle génération pour leur stabilité microstructurale à haute température qui permet l'augmentation du rendement. En service, les disques de turbine en superalliage sont principalement sollicités en fatigue à des températures intermédiaires, typiquement 450 °C. L'amorçage des fissures de fatigue dans cette classe d'alliage est contrôlé par de nombreux paramètres tels que le niveau de chargement, la température, l'environnement et la microstructure. De la température ambiante jusqu'aux températures intermédiaires, les joints de macles se trouvant dans les gros grains ont été identifiés comme responsables de l'apparition de nombreuses fissures de fatigue. L'objectif de cette thèse est de réaliser une analyse statistique des sites d'amorçage en fatigue à température ambiante pour plusieurs conditions de chargement et des mécanismes d'endommagement associés. Le matériau utilisé est l’AD730™ car ce superalliage polycristallin est représentatif de la famille des γ / γ' et que sa microstructure et ses propriétés mécaniques sont maintenant bien documentées. Comme déjà identifié dans la littérature, la majorité des fissures s'amorcent le long des joints de macles. L'orientation du glissement plastique par rapport à la surface libre le long du joint de macles a été identifiée comme un marqueur du niveau de chargement. En effet, les directions de glissement sont parallèles à la surface libre en endurance limité (HCF) alors qu'elles ont une incidence importante en fatigue oligocyclique (LCF). Ces résultats suggèrent que les mécanismes d'endommagement le long d'un joint de macles sont dépendants de l'amplitude de chargement. Une nouvelle configuration d'amorçage a été découverte : les fissures aux jonctions de joints de macles. Celles-ci ont été caractérisées pour plusieurs conditions d'essai et 2 microstructures différentes. Il est probable que ce type de site d'amorçage ait été confondu avec l'amorçage classique le long d'un joint de macles dans le passé. Pour finir, la taille de grains a été identifiée comme centrale dans le processus d'amorçage avec une cinétique d'apparition des fissures bien plus importante dans les gros grains.

This paper presents a symbolic and recursive calculation of the dynamic model of flexible parallel robots. In order to reduce the computational time, it is necessary to minimize the number of operators in the symbolic expression of the model. Some algorithms have been proposed for the rigid case, for parallel robots with lumped springs or for serial robots with distributed flexibilities, but to the best of our knowledge, nothing has been developed for parallel robots with distributed flexibilities. This paper aims at filling this gap. In order to minimize the number of operations, the Newton-Euler principle is used and combined with the principle of virtual powers. The Jacobian matrices defining the kinematic constraints are computed using recursive calculations that decrease the number of operators. The proposed algorithm is used to compute the elastodynamic model of a planar parallel robot. The obtained results, compared with those obtained with commercial softwares, show the validity of the proposed algorithm.

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La gestion des organisations hybrides, mêlant des logiques supposées incompatibles, représente un défi quotidien. Si les travaux suggèrent l’intérêt de combiner pleinement ces logiques à long terme pour garantir la pérennité de ces organisations, la littérature néo-institutionnelle fait surtout état des tensions, paradoxes et défis occasionnés. Le concept de business model hybride nous apparaît comme une piste prometteuse pour résoudre cette problématique, en mettant l’accent sur les interdépendances entre activités permettant la création de valeurs plurielles. Cette littérature émergente poursuit toutefois une vision dialectique de l’hybridité et peine à opérationnaliser l’articulation entre création de valeurs sociale et économique. En réponse, cet article propose d’adopter une approche systémique du business model hybride, de nature à proposer une compréhension holistique des activités concourant à une création de valeurs duale. Nous proposons l’étude d’un cas unique d’entreprise sociale, le Café Joyeux, combinant une logique économique et une logique sociale dans une offre de restauration. Nos résultats suggèrent que sept politiques hybrides sont articulées par l’organisation, suscitant tantôt des tensions entre logiques, tantôt leur renforcement mutuel. L’appréhension systémique du business model hybride permet ainsi de passer d’une vision dialectique à dialogique de l’hybridité, éclairant ce qui fonde la combinaison de logiques institutionnelles incompatibles.

In order to better understand the kinematics and geodynamics of the late Paleozoic to early Mesozoic transition from accretionary to intracontinental tectonics in the southwest Central Asian Orogenic Belt, we performed a paleomagnetic study on Lower Permian strata in the Turpan-Hami Basin, NW China. Magnetite and hematite are shown to be the principal magnetic remanence carriers. A typical sedimentary fabric that has not been modified by postdepositional deformation is recognized via magnetic fabric study. Stable characteristic remanent magnetizations, all of reverse magnetic polarity, are revealed by step demagnetizations. Remanence age is determined to be of Early Permian affinity, based on a fold test, remanence behavior of minerals, and geochronologic data. With inclination shallowing corrections, the first Early Permian paleomagnetic pole for the Turpan-Hami Block is acquired as λ = 75.7°N, φ = 276.3°E, A 95 = 5.7°, and N = 10 sites. Comparisons of this new pole with published ones from neighboring cratonic blocks provide kinematic constraints on the tectonic transition and subsequent intracontinental tectonics of this region. The Turpan-Hami and Yili blocks have kept their relative positions since the Early Permian. Significant latitudinal movement of 14.7°± 7.2°occurred between the Turpan-Hami and South Junggar blocks and could be mainly accommodated by late Paleozoic crustal shortening of at least~530 km across an intra-arc basin in the Bogda belt. The Turpan-Hami Block has experienced large-magnitude relative rotations of −41.1°± 7.1°a nd 21.2°± 9.4°with respect to Tarim and South Junggar since the Early Permian, respectively, corresponding to dominant intracontinental tectonics characterized by large-magnitude strike-slip displacements along megashear zones.

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The paper aims at presenting a Performance Measurement System (PMS) developed in an Italian project, performed by the authors within a Nonprofit Service Organization (NSO). Like profit organizations, nonprofit ones must measure their performances, in order to define possible improvements. The paper proposes a PMS, derived from the well known Balanced Scorecard approach, specifically dedicated to NSOs. In particular, a case study has been conducted within an Italian NSO, active in the construction sector, located in the Northern Italy, in the county of Bergamo.

We combine national income accounts, wealth aggregates, tax tabulations, rich lists, and surveys on income, consumption, and wealth in a consistent framework to present long run homogeneous series of income and wealth inequality in India. Our estimates suggest that inequality declined post-independence till the early 1980s, after which it began rising and has skyrocketed since the early 2000s. Trends of top income and wealth shares track each other over the entire period of our study. Between 2014-15 and 2022-23, the rise of top-end inequality has been particularly pronounced in terms of wealth concentration. By 2022-23, top 1% income and wealth shares (22.6% and 40.1%) are at their highest historical levels and India’s top 1% income share is among the very highest in the world. In line with earlier work, we find suggestive evidence that the Indian income tax system might be regressive when viewed from the lens of net wealth. We emphasize that the quality of economic data in India is notably poor and has seen a decline recently. It is therefore likely that our results represent a lower bound to actual inequality levels. We call for improved access to official data and greater transparency to enhance the study of inequality and enable evidence-based public debates.

Measurements of logistics costs are necessary for manufacturing companies to be able to evaluate the cost effects and trade-offs of logistics management decisions. This case study highlights the challenges ZF Friedrichshafen AG faced during the implementation of a process-oriented logistics-costs measurement framework. The discussion of possible solutions to these challenges leads to recommendations for research as well as industrial practice. Specifically, a greater degree of co-operation between logisticians and cost accountants seems necessary in both academia and industry in order to develop more standardized logistics-costs measurement methods.