97 research outputs found
The Lunar Lander Neutron and Dosimetry (LND) Experiment on Chang'E 4
Chang'E 4 is the first mission to the far side of the Moon and consists of a
lander, a rover, and a relay spacecraft. Lander and rover were launched at
18:23 UTC on December 7, 2018 and landed in the von K\'arm\'an crater at 02:26
UTC on January 3, 2019. Here we describe the Lunar Lander Neutron \& Dosimetry
experiment (LND) which is part of the Chang'E 4 Lander scientific payload. Its
chief scientific goal is to obtain first active dosimetric measurements on the
surface of the Moon. LND also provides observations of fast neutrons which are
a result of the interaction of high-energy particle radiation with the lunar
regolith and of their thermalized counterpart, thermal neutrons, which are a
sensitive indicator of subsurface water content.Comment: 38 pages, submitted to Space Science Review
Non-steady state chloride migration and binding in cracked self-compacting concrete
We adopted a notch method to study the influence of crack width (macro level) on chloride transport and binding of cracked concrete under a non-steady state migration test. The results show that migration coefficient of cracked concrete increases with increasing crack width up to a critical value (0.43 mm), for the whole concrete or the area close to crack; the increase of migration coefficient could be independent from crack parameter when a critical crack width is reached. For chloride binding, Langmuir isotherms of cracked concrete samples exhibit the similar decreasing trend as crack width increases from 0.27 to 1.96 mm. The increased current value could be responsible for the trend based on the hypothesis of electric force
Integrative multiâomics analyses of date palm (Phoenix dactylifera) roots and leaves reveal how the halophyte land plant copes with sea water
Date palm (Phoenix dactylifera L.) is able to grow and complete its life cycle while being rooted in highly saline soils. Which of the many well-known salt-tolerance strategies are combined to fine-tune this remarkable resilience is unknown. The precise location, whether in the shoot or the root, where these strategies are employed remains uncertain, leaving us unaware of how the various known salt-tolerance mechanisms are integrated to fine-tune this remarkable resilience. To address this shortcoming, we exposed date palm to a salt stress dose equivalent to seawater for up to 4 weeks and applied integrative multi-omics analyses followed by targeted metabolomics, hormone, and ion analyses. Integration of proteomic into transcriptomic data allowed a view beyond simple correlation, revealing a remarkably high degree of convergence between gene expression and protein abundance. This sheds a clear light on the acclimatization mechanisms employed, which depend on reprogramming of protein biosynthesis. For growth in highly saline habitats, date palm effectively combines various salt-tolerance mechanisms found in both halophytes and glycophytes: âavoidanceâ by efficient sodium and chloride exclusion at the roots, and âacclimationâ by osmotic adjustment, reactive oxygen species scavenging in leaves, and remodeling of the ribosome-associated proteome in salt-exposed root cells. Combined efficiently as in P. dactylifera L., these sets of mechanisms seem to explain the palm's excellent salt stress tolerance
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