SEIS: Insight's Seismic Experiment for Internal Structure of Mars.

By the end of 2018, 42 years after the landing of the two Viking seismometers on Mars, InSight will deploy onto Mars' surface the SEIS (Seismic Experiment for Internal Structure) instrument; a six-axes seismometer equipped with both a long-period three-axes Very Broad Band (VBB) instrument and a three-axes short-period (SP) instrument. These six sensors will cover a broad range of the seismic bandwidth, from 0.01 Hz to 50 Hz, with possible extension to longer periods. Data will be transmitted in the form of three continuous VBB components at 2 sample per second (sps), an estimation of the short period energy content from the SP at 1 sps and a continuous compound VBB/SP vertical axis at 10 sps. The continuous streams will be augmented by requested event data with sample rates from 20 to 100 sps. SEIS will improve upon the existing resolution of Viking's Mars seismic monitoring by a factor of ∼ 2500 at 1 Hz and ∼ 200 000 at 0.1 Hz. An additional major improvement is that, contrary to Viking, the seismometers will be deployed via a robotic arm directly onto Mars' surface and will be protected against temperature and wind by highly efficient thermal and wind shielding. Based on existing knowledge of Mars, it is reasonable to infer a moment magnitude detection threshold of M w ∼ 3 at 40 ∘ epicentral distance and a potential to detect several tens of quakes and about five impacts per year. In this paper, we first describe the science goals of the experiment and the rationale used to define its requirements. We then provide a detailed description of the hardware, from the sensors to the deployment system and associated performance, including transfer functions of the seismic sensors and temperature sensors. We conclude by describing the experiment ground segment, including data processing services, outreach and education networks and provide a description of the format to be used for future data distribution.Electronic supplementary materialThe online version of this article (10.1007/s11214-018-0574-6) contains supplementary material, which is available to authorized users

First International External Quality Assessment Study on Molecular and Serological Methods for Yellow Fever Diagnosis

Objective: We describe an external quality assurance (EQA) study designed to assess the efficiency and accurateness of molecular and serological methods used by expert laboratories performing YF diagnosis. Study Design: For molecular diagnosis evaluation, a panel was prepared of 14 human plasma samples containing specific RNA of different YFV strains (YFV-17D, YFV South American strain [Brazil], YFV IvoryC1999 strain), and specificity samples containing other flaviviruses and negative controls. For the serological panel, 13 human plasma samples with anti-YFVspecific antibodies against different strains of YFV (YFV-17D strain, YFV IvoryC1999 strain, and YFV Brazilian strain), as well as specificity and negative controls, were included. Results: Thirty-six laboratories from Europe, the Americas, Middle East, and Africa participated in these EQA activities. Only 16% of the analyses reported met all evaluation criteria with optimal performance. Serial dilutions of YFV-17D showed that in general the methodologies reported provided a suitable sensitivity. Failures were mainly due to the inability to detect wild-type strains or the presence of false positives. Performance in the serological diagnosis varied, mainly depending on the methodology used. Anti-YFV IgM detection was not performed in 16% of the reports using IIF or ELISA techniques, although it is preferable for the diagnosis of YFV acute infections. A good sensitivity profile was achieved in general; however, in the detection of IgM antibodies a lack of sensitivity of anti-YFV antibodies against the vaccine strain 17D was observed, and of the anti-YFV IgG antibodies against a West African strain. Neutralization assays showed a very good performance; however, the unexpected presence of false positives underlined the need of improving the running protocols. Conclusion: This EQA provides information on each laboratory’s efficacy of RT-PCR and serological YFV diagnosis techniques. The results indicate the need for improving serological and molecular diagnosis techniques and provide a follow-up of the diagnostic profiles

Chikungunya Disease: Infection-Associated Markers from the Acute to the Chronic Phase of Arbovirus-Induced Arthralgia

At the end of 2005, an outbreak of fever associated with joint pain occurred in La Réunion. The causal agent, chikungunya virus (CHIKV), has been known for 50 years and could thus be readily identified. This arbovirus is present worldwide, particularly in India, but also in Europe, with new variants returning to Africa. In humans, it causes a disease characterized by a typical acute infection, sometimes followed by persistent arthralgia and myalgia lasting months or years. Investigations in the La Réunion cohort and studies in a macaque model of chikungunya implicated monocytes-macrophages in viral persistence. In this Review, we consider the relationship between CHIKV and the immune response and discuss predictive factors for chronic arthralgia and myalgia by providing an overview of current knowledge on chikungunya pathogenesis. Comparisons of data from animal models of the acute and chronic phases of infection, and data from clinical series, provide information about the mechanisms of CHIKV infection–associated inflammation, viral persistence in monocytes-macrophages, and their link to chronic signs

A new lunar crustal thickness model constrained by converted seismic waves detected beneath the Apollo seismic network

Analysis of conversions between compressional and shear waves is a workhorse method for constraining crustal and lithospheric structure on Earth; yet, such converted waves have not been unequivocally identified in seismic data from the largest events on the Moon, due to the highly scattered waveforms of shallow seismic events. We reanalyze the polarization attributes of waveforms recorded by the Apollo seismic network to identify signals with rectilinear particle motion below 1 Hz, arising from conversions across the crust-mantle boundary. Delay times of these converted waves are inverted to estimate crustal thickness and wavespeeds beneath the seismometers. Combined with gravimetric modeling, these new crustal thickness tie-points yield an updated lunar crustal model with an average thickness of 29–47 km. Unlike previous models, ours include explicit uncertainty estimates, offering critical context for future lunar missions, geophysical studies, and predicting 15–36 km crust at Schrödinger and 29–52 km at Artemis III sites

Thickness and structure of the Martian crust from InSight seismic data

A planet's crust bears witness to the history of planetary formation and evolution, but for Mars, no absolute measurement of crustal thickness has been available. Here, we determine the structure of the crust beneath the InSight landing site on Mars using both marsquake recordings and the ambient wavefield. By analyzing seismic phases that are reflected and converted at subsurface interfaces, we find that the observations are consistent with models with at least two and possibly three interfaces. If the second interface is the boundary of the crust, the thickness is 20 +/- 5 kilometers, whereas if the third interface is the boundary, the thickness is 39 +/- 8 kilometers. Global maps of gravity and topography allow extrapolation of this point measurement to the whole planet, showing that the average thickness of the martian crust lies between 24 and 72 kilometers. Independent bulk composition and geodynamic constraints show that the thicker model is consistent with the abundances of crustal heat-producing elements observed for the shallow surface, whereas the thinner model requires greater concentration at depth.M.P.P., S.T., E.B., S.E.S., and W.B.B. were supported by the NASA InSight mission and funds from the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. F.B. was supported by research grant ETH-05 17-1. A.K., D.G., M.v.D., and S.S. acknowledge funding by the Swiss National Science Foundation and the Swiss State Secretariat for Education, Research and Innovation, and support from ETHZ through the ETH+ funding scheme (ETH+02 19-1). V.L. and D.K. acknowledge funding from a Packard Foundation Fellowship to V.L. B.T. is supported by the European Union’s Horizon 2020 research and innovation program under Marie Sklodowska-Curie grant agreement 793824. French co-authors acknowledge the support of CNES and ANR (MAGIS, ANR-19-CE31-0008-08). N.S. was supported by NASA grant 80NSSC18K1628. E.B. was funded through NASA Participating Scientist Program grant 80NSSC18K1680. A.-C.P. gratefully acknowledges the financial support and endorsement from the DLR Management Board Young Research Group Leader Program and the Executive Board Member for Space Research and Technology. Geodynamical models used in this work were performed on the supercomputer ForHLR funded by the Ministry of Science, Research and the Arts Baden-Württemberg and by the Federal Ministry of Education and Research. S.M.M. was funded through NASA InSight Participating Scientist Program award no. 80NSSC18K1622. C.M. acknowledges the support of the Institut Universitaire de France (IUF). C.L.J. and A.M. acknowledge support from the InSight Mission, the Canadian Space Agency, and ETH Zurich (ETH fellowship 19-2 FEL-34). N.B. is supported by research grant ETH-06 17-02. The work of A.R. was financially supported by the Belgian PRODEX program managed by the European Space Agency in collaboration with the Belgian Federal Science Policy Offic