How to Simulate the Surface of a Cometary Nucleus for Public Science Demonstrations

International audienceTo celebrate and appropriately illustrate the rendezvous of the European Rosetta spacecraft with comet 67P/Churyumov– Gerasimenko and the landing of Philae on the surface of the comet’s nucleus on 12 November 2014, the French science museum Palais de la Découverte developed and presented a new and original demonstration. The experiment simulates the behaviour of a cometary surface in a vacuum and shows the formation of jet-like features. We explain here how to prepare an analogue to cometary material from porous ices and carbon, how to approximately reproduce the cometary environment at low pressure, temperature and solar illumination, and how to present the experiment at a public science demonstration

Seawater osmium isotope evidence for a middle Miocene flood basalt event in ferromanganese crust records

Three ferromanganese crusts from the northeast, northwest and central Atlantic were re-dated using osmium (Os) isotope stratigraphy and yield ages from middle Miocene to the present. The three Os isotope records do not show evidence for growth hiatuses. The reconstructed Os isotope-based growth rates for the sections older than 10 Ma are higher than those determined previously by the combined beryllium isotope (10Be/9Be) and cobalt (Co) constant-flux methods, which results in a decrease in the maximum age of each crust. This re-dating does not lead to significant changes to the interpretation of previously determined radiogenic isotope neodymium, lead (Nd, Pb) time series because the variability of these isotopes was very small in the records of the three crusts prior to 10 Ma. The Os isotope record of the central Atlantic crust shows a pronounced minimum during the middle Miocene between 15 and 12 Ma, similar to a minimum previously observed in two ferromanganese crusts from the central Pacific. For the other two Atlantic crusts, the Os isotope records and their calibration to the global seawater curve for the middle Miocene are either more uncertain or too short and thus do not allow for a reliable identification of an isotopic minimum. Similar to pronounced minima reported previously for the Cretaceous/Tertiary and Eocene/Oligocene boundaries, possible interpretations for the newly identified middle Miocene Os isotope minimum include changes in weathering intensity and/or a meteorite impact coinciding with the formation of the Nördlinger Ries Crater. It is suggested that the eruption and weathering of the Columbia River flood basalts provided a significant amount of the unradiogenic Os required to produce the middle Miocene minimum

The Comet Interceptor Mission

Here we describe the novel, multi-point Comet Interceptor mission. It is dedicated to the exploration of a little-processed long-period comet, possibly entering the inner Solar System for the first time, or to encounter an interstellar object originating at another star. The objectives of the mission are to address the following questions: What are the surface composition, shape, morphology, and structure of the target object? What is the composition of the gas and dust in the coma, its connection to the nucleus, and the nature of its interaction with the solar wind? The mission was proposed to the European Space Agency in 2018, and formally adopted by the agency in June 2022, for launch in 2029 together with the Ariel mission. Comet Interceptor will take advantage of the opportunity presented by ESA’s F-Class call for fast, flexible, low-cost missions to which it was proposed. The call required a launch to a halo orbit around the Sun-Earth L2 point. The mission can take advantage of this placement to wait for the discovery of a suitable comet reachable with its minimum ΔV capability of 600 ms−1. Comet Interceptor will be unique in encountering and studying, at a nominal closest approach distance of 1000 km, a comet that represents a near-pristine sample of material from the formation of the Solar System. It will also add a capability that no previous cometary mission has had, which is to deploy two sub-probes – B1, provided by the Japanese space agency, JAXA, and B2 – that will follow different trajectories through the coma. While the main probe passes at a nominal 1000 km distance, probes B1 and B2 will follow different chords through the coma at distances of 850 km and 400 km, respectively. The result will be unique, simultaneous, spatially resolved information of the 3-dimensional properties of the target comet and its interaction with the space environment. We present the mission’s science background leading to these objectives, as well as an overview of the scientific instruments, mission design, and schedule

Significance of iron isotope mineral fractionation in pallasites and iron meteorites for the core-mantle differentiation of terrestrial planets [rapid communication]

International audienceSeven bulk chondrites, with ?57Fe/54Fe values between ?0.1? and 0? relative to IRMM-14, tend to be slightly lighter than 11 bulk iron meteorites, which have ?57Fe/54Fe values ranging from 0.04? to 0.2?. At the mineral scale, taenite from two iron meteorites, Cranbourne and Toluca, shows ?57Fe/54Fe values heavier by up to 0.3? than their kamacite counterpart, thus calling into question the significance of bulk iron meteorite data. On three pallasites (Esquel, Marjalahti and Springwater) we measured a heavier iron isotope composition for the metal fractions compared to the coexisting olivines as previously observed on two other pallasites (Eagle Station and Imilac), but the range of ?57Fe/54Fe differences (from 0.32? to 0.07?) is larger than that originally found. Troilite from two pallasites appears to be even heavier than the metal fraction, whereas schreibersite is lighter than its olivine counterpart. There is thus a general tendency for minerals within a given rock to show a heavier Fe isotope composition as the coordination number of Fe increases, although troilite is an exception to this rule. Iron meteorites are classically considered as remnants of asteroid cores and pallasites as core mantle interfaces. The simultaneous finding that the metal fractions of pallasites have a higher ?57Fe/54Fe signature than the coexisting olivines, and that the iron meteorites are slightly heavier than chondrites could be taken as an indication that planetary core mantle differentiation is accompanied by sizeable iron isotope fractionation. In this hypothesis, mass balance constraints imply that resultant planetary mantles should be isotopically lighter than the chondritic starting material. That is not observed, however, since all planetary mantles analyzed so far have ?57Fe/54Fe values equivalent to or heavier than those of chondrites. It thus appears that the moderate temperature and pressure metal silicate fractionation that occurred in pallasite and iron parent bodies is not readily transposable to planets as far as Fe isotopes are concerned. Instead, these mantle signatures could reflect equilibrium fractionation at a higher temperature, or the lack of a global core mantle equilibration at the planetary scale. Overall, these new results show that the mass-dependent isotopic scatter observed among inner solar system bodies from the bulk-rock to the planetary scale (?0.3? ?57Fe/54Fe) is more restricted than previously thought. This likely confirms a homogenization process that occurred in the protoplanetary accretion disk, between refractory inclusion condensation and chondrule formation

Complete genome sequence of Mycobacterium sp. Strain 3519A

International audienceMycobacterium sp. strain 3519A is a nontuberculous mycobacterium isolated from sputum from a Cambodian patient with a pulmonary infection. We report here the first complete 7.3-Mbp-long genome sequence of Mycobacterium sp. 3519A with 66.35% GC content, encoding 7,029 protein-coding genes, 50 tRNAs, and 5 rRNA genes

Complete Genome Sequence of Mycobacterium sp. Strain 4858

International audienceMycobacterium sp. strain 4858 is a nontuberculous mycobacterium isolated from sputum in a Cambodian patient with a pulmonary infection. We report the first complete 5.6-Mbp-long genome sequence of Mycobacterium strain 4858, with 68.24% GC content, carrying 5,255 protein-coding genes, 47 tRNAs, and 3 rRNA genes

Osmium, tungsten, and chromium isotopes in sediments and in Ni-rich spinel at the K-T boundary: Signature of a chondritic impactor

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Maintaining good relationships in clinical setting : the bonus DOMUS project

The DOMUS laboratory has recently participated in the construction of a brand new residence for persons with Traumatic Brain Injury (TBI). This building which comprises six apartments, and four bedrooms is equipped with the latest smart home technology (sensors, effectors, etc.). It is a living lab where prototype software, algorithms and technologies can be deployed for long term evaluation. One of the challenges that we have to face in a living lab setting is the maintaining of the good relationships with both the professionals and the residents. In that regard, the DOMUS team worked toward implementing simple technological services that would rapidly and directly enhance social participation and the quality of life of the residents. The goal is also to motivate them into taking part of the various research projects and to establish a trust relationship. In this paper, we present the Bonus DOMUS, a project that was created toward these aims. It enables the residents to have customized alarms and motivational messages

Identification of lactic acid bacteria and rhizobacteria by ultraviolet-visible-near infrared spectroscopy and multivariate classification

International audienceThe biological processes of interest to agro-industry involve numerous bacterial species. Lactic acid bacteria produce metabolites capable of fermenting food products and modifying their organoleptic properties, and plant-growth-promoting rhizobacteria can act as biofertilizers, biostimulants, or biocontrol agents in agriculture. The protocol of conventional techniques for bacterial identification, currently based on genotyping and phenotyping, require specific sample preparation and destruction. The work presented herein details a method for rapid identification of lactic acid bacteria and rhizobacteria at the genus and species level. To develop the method, bacteria were inoculated on an agar medium and analyzed by near infrared (NIR) and ultraviolet-visible-NIR (UV-Vis-NIR) spectroscopy. Artificial neural network models applied to the UV-Vis-NIR spectra correctly identified the genus (species) of 70% (63%) of the lactic acid bacteria and 67% of the rhizobacteria on an independent prediction set of unknown bacterial strains. These results demonstrate the potential of UV-Vis-NIR spectroscopy to identify bacteria directly on agar plates