On the origin and evolution of the material in 67P/Churyumov-Gerasimenko

International audiencePrimitive objects like comets hold important information on the material that formed our solar system. Several comets have been visited by spacecraft and many more have been observed through Earth- and space-based telescopes. Still our understanding remains limited. Molecular abundances in comets have been shown to be similar to interstellar ices and thus indicate that common processes and conditions were involved in their formation. The samples returned by the Stardust mission to comet Wild 2 showed that the bulk refractory material was processed by high temperatures in the vicinity of the early sun. The recent Rosetta mission acquired a wealth of new data on the composition of comet 67P/Churyumov-Gerasimenko (hereafter 67P/C-G) and complemented earlier observations of other comets. The isotopic, elemental, and molecular abundances of the volatile, semi-volatile, and refractory phases brought many new insights into the origin and processing of the incorporated material. The emerging picture after Rosetta is that at least part of the volatile material was formed before the solar system and that cometary nuclei agglomerated over a wide range of heliocentric distances, different from where they are found today. Deviations from bulk solar system abundances indicate that the material was not fully homogenized at the location of comet formation, despite the radial mixing implied by the Stardust results. Post-formation evolution of the material might play an important role, which further complicates the picture. This paper discusses these major findings of the Rosetta mission with respect to the origin of the material and puts them in the context of what we know from other comets and solar system objects

Current approaches to the study of the ancient weight systems

The main issue in recent years of the near eastern metrological studies is the research on the interconnections of the different economic regional spheres and, above all, of the different weighing systems. It is now ascertained that the same major units, or very close major units, the talent and the mina, were widespread in the whole eastern Mediterranean, both in the Levant and in the Aegean. The different main Levantine shekels, the shekel of Khatti (11,75 g, h), the shekel of Ugarit (9,4 g., s), and the shekel of Karkemish (7,83 g, k) over time became widespread and interconnected with a simple ratio between them; they were counted also, in case of necessity, on a decimal and a sexagesimal basis. The various Mediterranean wool units were very close to each other. Thus, in the framework of a complex system of deep and important regional exchanges, the backbone of the Eastern Mediterranean world in the Bronze Age, the interconnections between various regional weighing systems are clear and intense. In this general and regional pattern, it is necessary to understand the fractures, the differences, the contradictions and the evolutions inside the ancient weighing phenomena, on the basis of the survived weighing tools. This is the basic idea of a historical metrology, focusing on each period; at the same time, in a diachronic perspective, it will help us to outline the complex links between the weighing systems of the ancient Mediterranean. In this view, some very elementary tools are needed which can be resumed as follows: Chronology \u2013 The date should be the first element to be considered when studying a balance weight set, or simply an archaeological assemblage; Typology \u2013 The main weight types of the Bronze Age Mediterranean are already known, but we still need an explicit definition of certain typological criteria such as durable material, high specific weight, distinguished shape. Archaeological context and function - the find spot and the associated material are very important to understand the different functions of a set. Weighing tools are indispensable instruments of quantification and calculation, and are therefore found in every kind of context, probably connected to many different functions: houses of various type (household production), work areas of different nature and size (craft and \u201cindustrial\u201d production), storerooms (storage), harbours (trade and others activities), palaces and temples (public administrations and others activities). They invest every sphere of material and daily life. Sometimes, they also probably had symbolic meanings, as it has been suggested by their presence in funerary assemblages or in religious contexts

A rapid assessment approach for public, health decision-making related to the prevention of malaria during pregnancy

OBJECTIVE: To develop a rapid field assessment methodology to address the burden of malaria during pregnancy and the options for intervening within the existing antenatal care system in Kenya. METHODS: Surveys consisting of questionnaires, sampling of blood for parasitaemia and anaemia, and birth outcome assessment were conducted in antenatal clinics, delivery units, and in the community in Kisumu and Mombasa, Kenya. FINDINGS: The rates of maternal anaemia and severe anaemia, were, respectively, 79% and 8% in Kisumu, and 95% and 24% in Mombasa. The rates of placental parasitaemia were 27% and 24% and the rates of low birth weight were 18% and 24% in Kisumu and Mombasa, respectively. Women with placental parasitaemia had a higher incidence of low birth weight compared with women without placental parasitaemia in both Kisumu (28% vs 16%, P=0.004) and Mombasa (42% vs 20%, P=0.004). A total of 95% and 98% of women in Kisumu and Mombasa, respectively, reported attending an antenatal clinic during their previous pregnancy. CONCLUSION: This methodology can be used by ministries of health to collect data for decision-making regarding malaria control during pregnancy; it can also provide a baseline measurement on which to evaluate subsequent interventions

Resistance training-induced changes in integrated myofibrillar protein synthesis are related to hypertrophy only after attenuation of muscle damage

Key points Skeletal muscle hypertrophy is one of the main outcomes from resistance training (RT), but how it is modulated throughout training is still unknown. We show that changes in myofibrillar protein synthesis (MyoPS) after an initial resistance exercise (RE) bout in the first week of RT (T1) were greater than those seen post-RE at the third (T2) and tenth week (T3) of RT, with values being similar at T2 and T3. Muscle damage (Z-band streaming) was the highest during post-RE recovery at T1, lower at T2 and minimal at T3. When muscle damage was the highest, so was the integrated MyoPS (at T1), but neither were related to hypertrophy; however, integrated MyoPS at T2 and T3 were correlated with hypertrophy. We conclude that muscle hypertrophy is the result of accumulated intermittent increases in MyoPS mainly after a progressive attenuation of muscle damage. AbstractSkeletal muscle hypertrophy is one of the main outcomes of resistance training (RT), but how hypertrophy is modulated and the mechanisms regulating it are still unknown. To investigate how muscle hypertrophy is modulated through RT, we measured day-to-day integrated myofibrillar protein synthesis (MyoPS) using deuterium oxide and assessed muscle damage at the beginning (T1), at 3weeks (T2) and at 10weeks of RT (T3). Ten young men (27(1)years, mean (SEM)) had muscle biopsies (vastus lateralis) taken to measure integrated MyoPS and muscle damage (Z-band streaming and indirect parameters) before, and 24h and 48h post resistance exercise (post-RE) at T1, T2 and T3. Fibre cross-sectional area (fCSA) was evaluated using biopsies at T1, T2 and T3. Increases in fCSA were observed only at T3 (P=0.017). Changes in MyoPS post-RE at T1, T2 and T3 were greater at T1 (