Chemical analysis of pottery demonstrates prehistoric origin for high-altitude alpine dairying

The European high Alps are internationally renowned for their dairy produce, which are of huge cultural and economic significance to the region. Although the recent history of alpine dairying has been well studied, virtually nothing is known regarding the origins of this practice. This is due to poor preservation of high altitude archaeological sites and the ephemeral nature of transhumance economic practices. Archaeologists have suggested that stone structures that appear around 3,000 years ago are associated with more intense seasonal occupation of the high Alps and perhaps the establishment of new economic strategies. Here, we report on organic residue analysis of small fragments of pottery sherds that are occasionally preserved both at these sites and earlier prehistoric rock-shelters. Based mainly on isotopic criteria, dairy lipids could only be identified on ceramics from the stone structures, which date to the Iron Age (ca. 3,000 - 2,500 BP), providing the earliest evidence of this practice in the high Alps. Dairy production in such a marginal environment implies a high degree of risk even by today’s standards. We postulate that this practice was driven by population increase and climate deterioration that put pressure on lowland agropastoral systems and the establishment of more extensive trade networks, leading to greater demand for highly nutritious and transportable dairy products

Sediment source fingerprinting: benchmarking recent outputs, remaining challenges and emerging themes

Abstract: Purpose: This review of sediment source fingerprinting assesses the current state-of-the-art, remaining challenges and emerging themes. It combines inputs from international scientists either with track records in the approach or with expertise relevant to progressing the science. Methods: Web of Science and Google Scholar were used to review published papers spanning the period 2013–2019, inclusive, to confirm publication trends in quantities of papers by study area country and the types of tracers used. The most recent (2018–2019, inclusive) papers were also benchmarked using a methodological decision-tree published in 2017. Scope: Areas requiring further research and international consensus on methodological detail are reviewed, and these comprise spatial variability in tracers and corresponding sampling implications for end-members, temporal variability in tracers and sampling implications for end-members and target sediment, tracer conservation and knowledge-based pre-selection, the physico-chemical basis for source discrimination and dissemination of fingerprinting results to stakeholders. Emerging themes are also discussed: novel tracers, concentration-dependence for biomarkers, combining sediment fingerprinting and age-dating, applications to sediment-bound pollutants, incorporation of supportive spatial information to augment discrimination and modelling, aeolian sediment source fingerprinting, integration with process-based models and development of open-access software tools for data processing. Conclusions: The popularity of sediment source fingerprinting continues on an upward trend globally, but with this growth comes issues surrounding lack of standardisation and procedural diversity. Nonetheless, the last 2 years have also evidenced growing uptake of critical requirements for robust applications and this review is intended to signpost investigators, both old and new, towards these benchmarks and remaining research challenges for, and emerging options for different applications of, the fingerprinting approach

Conception et fabrication des systèmes de chauffage

Les systèmes de chauffage sont les outils nécessaires pour explorer et étendre le domaine opérationnel d’ITER. Ils sont employés pour augmenter l’énergie stockée dans le plasma, pour créer le courant dans le plasma, et pour contrôler divers paramètres tels que la température des particules, la distribution de courant, les gradients de température, etc. Comme le plasma est composé de particules chargées dans un champ magnétique, 2 types de systèmes de chauffage peuvent être employés. Le premier type emploie des faisceaux de neutres, qui sont des faisceaux de grande énergie, formés de particules électriquement neutres qui peuvent traverser les champs magnétiques du tokamak. Ces faisceaux sont injectés dans le plasma où ils sont aisément ionisés par une variété de réactions avec les ions et les électrons du plasma ; une fois ionisées, les particules sont piégées et confinées dans le plasma par les champs magnétiques. Pendant qu’elles circulent autour du tore, elles transfèrent leur énergie au plasma par des collisions, chauffant directement les ions et les électrons. Un transfert de moment se produit également pendant les collisions, induisant la rotation du plasma et la création d’un courant dans le plasma. Les faisceaux de neutres d’ITER devraient injecter 33 MW d’atomes de deutérium (D0) à partir de deux injecteurs. Les faisceaux sont créés en neutralisant les ions négativement chargés de deutérium (D-) qui ont été électrostatiquement accélérés à 1 MeV. Les domaines de la R&D sont le développement de la source, l’accélérateur 1 MeV et les alimentations électriques associées. Les défis sont le niveau de la puissance exigée à 1 MeV et la production d’un fl ux uniforme de D- sur la section de l’accélérateur, à la densité de courant exigée. Le deuxième type de système de chauffage concerne le domaine des systèmes radiofréquences (RF), le plasma jouant le rôle de récepteur. L’énergie est couplée préférentiellement aux espèces ou aux régions choisies du plasma selon la fréquence, la polarisation ou le spectre de l’onde injectée dans le plasma. Les systèmes RF peuvent également être employés pour contrôler les instabilités du plasma. La puissance est transférée aux électrons et plus tard aux ions, ou directement aux ions. Les systèmes RF qui seront installés dès le début d’ITER sont le système du chauffage par résonance de cyclotronique électronique (ECRH), à 170 gigahertz, et le système du chauffage par résonance de cyclotronique ionique (ICRH), fonctionnant dans la gamme des 40 à 55 mégahertz. Ils doivent chacun délivrer 20 MW au plasma d’ITER. Plus tard un système à la fréquence hybride inférieure (LHCD) pourrait être installé, à une fréquence fixe à choisir entre 3 et 5 gigahertz. Les domaines de développement sont le tube de haute puissance RF (gyrotron pour l’ECRH, klystron pour l’LHCD, tétrode pour l’ICRH), la ligne de transmission, et les structures de couplage (antenne pour ICRH, rangée de guide d’ondes pour LHCD, et miroirs pour ECRH). Les défis sont le niveau de puissance unitaire des tubes, la densité de puissance et l’efficacité des lignes de transmission, et le couplage au plasma pour les antennes. Cet article donne une description des différents systèmes de chauffage, avec les difficultés techniques rencontrées et les programmes de R&D associés

The LINAC4 Power Coupler

Linac4 is employing three types of accelerating structures after the RFQ: a Drift Tube Linac (DTL), a Cell- Coupled DTL (CCDTL), and a Pi-Mode Structure (PIMS) to accelerate the beam up to 160 MeV at 352.2MHz. The structures are designed for a peak power of approximately 1 MW per power coupler, which is transported via rectangular waveguides from the klystron gallery to the RF cavities. The coupler itself consists of two parts: a ceramic window, which separates the cavity vacuum from the air in the waveguides, and a Tuner-adjustablewaveguide Coupler (TaCo), which couples the RF power through an iris to the cavity. In the frame of the Linac4 R&D both devices have been significantly improvedwith respect to their commonly used design. On the coupler side, the waveguide short circuit with its matched length has been replaced by a fixedlength /4 short circuit. The RF matching is done by a simple piston tuner, which allows a quick matching to different cavity quality factors. In the window part, which usually consists of a ceramic disc and 2 pieces of waveguides with matching elements, the waveguide sections could be completely suppressed, so that the window became very compact, lightweight, and much simpler to manufacture. In this paper we present electromagnetic simulations, and tests on first prototypes, which were constructed at CERN

A 4D sedimentological approach to reconstructing the flood frequency and intensity of the Rhône River (Lake Bourget, NW European Alps)

A high-resolution sedimentological study of Lake Bourget was conducted to reconstruct the flood frequency and intensity (or magnitude) in the area over the last 350 years. Particular emphasis was placed on investigating the spatio-temporal distribution of flood deposits in this large lake basin. The thicknesses of deposits resulting from 30 flood events of the Rhoˆne River were collected over a set of 24 short sediment cores. Deposit thicknesses were compared with instrumental data for the Rhoˆne River discharge for the period from 1853 to 2010. The results show that flood frequency and intensity cannot be reliably reconstructed from a single core because of the inhomogeneous flood-deposit geometry in such a large lake. From all documented flood-deposit thicknesses, volumes of sediment brought into the lake during each flood event were computed through a Kriging procedure and compared with the historical instrumental data. The results show, in this study, that reconstructed sediment volumes are well correlated to maximal flood discharges. This significant correlation suggests that the increase of embankment and dam settlements on the Rhoˆne River during the last 150 years has not significantly affected the transport of the smallest sediment fraction during major flood events. Hence, assessment of the flood-sediment volumes deposited in the large Lake Bourget is the only way to reliably reconstruct the flood frequency and intensity

Nirmatrelvir/ritonavir: Efficacy, safety and drug monitoring in a real-life cohort of outpatient liver transplant recipients

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