Submicroscopic organization of Chlorella cells cultivated under space flight conditions in three-component aquatic system has been studied. Comparison of the experimental cells with that of the controls revealed certain rearrangements of cell organelles particularly, a reduction in the amount of reserve polysaccharides in chloroplasts, increase of cell vacuolization and mitochondrion volume, complication configuration of plasmalemma evaginations and invaginations, and also disturbances in the process of cytokinesis. More over an increase in the number of Chlorella cells infected by bacteria was shown in the experimental variant. No considerable differences were established in the growth characteristics of the experimental and control populations. A comparative cytological analysis revealed general regularities of organelles in Chlorella cells cultivated under space flight condition in the uni- and multicomponent systems.
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http://dx.doi.org/10.1016/0273-1177(89)90059-8 | DOI Listing |
Nature
January 2025
Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA.
Evaporation or freezing of water-rich fluids with dilute concentrations of dissolved salts can produce brines, as observed in closed basins on Earth and detected by remote sensing on icy bodies in the outer Solar System. The mineralogical evolution of these brines is well understood in regard to terrestrial environments, but poorly constrained for extraterrestrial systems owing to a lack of direct sampling. Here we report the occurrence of salt minerals in samples of the asteroid (101955) Bennu returned by the OSIRIS-REx mission.
View Article and Find Full Text PDFTime-of-flight Lidars based on single-photon avalanche diode (SPAD) detector arrays are emerging as a strong candidate technology for long range three-dimensional imaging in challenging environmental conditions. However, reaching this bound requires the existence of an unbiased estimator, which does not necessarily exist for data acquired by realistic SPAD-based Lidar systems. Here, we extend our existing SPAD Lidar modelling framework to include a novel metric, which we term the 'Binomial Separation Criterion', as a means of quantifying whether a depth estimation algorithm will reach the Cramér-Rao bound (CRB).
View Article and Find Full Text PDFSci Rep
January 2025
Space Science Division, Korea Astronomy and Space Science Institute, Daejeon, 34055, Republic of Korea.
This paper reports the proton response function for solution-grown trans-stilbene scintillator from 1 to 25 MeVee and its application for unfolding neutron spectra of Cf-252 and AmBe sources. Low energy proton response was measured by the Time-of-Flight technique at the Korea Research Institute of Standards and Science. In contrast, high energy response was investigated using a 45 MeV proton beam at the Korea Institute of Radiological & Medical Sciences.
View Article and Find Full Text PDFSci Rep
January 2025
Departament de Fisica de la Materia Condensada, University of Barcelona, Marti i Franquès 1, 08028, Barcelona, Spain.
We present a nonlinear model of thermal field emission in resonant tunneling nanostructures with multiple barriers and potential wells, based on an accurate determination of the quantum potential shape and a rigorous solution of the Schrödinger equation, while considering thermal balance. The model applies to vacuum and semiconductor resonant tunnel diode and triode structures with two and three electrodes and to the general case of two-way tunneling with electrode heating. The complete balance of heat release and transfer is accounted for, with heat transport considered ballistic.
View Article and Find Full Text PDFNat Commun
January 2025
NUS Environmental Research Institute, National University of Singapore, Singapore, Singapore.
Southeast Asia (SEA) contributes approximately one-third of global land-use change carbon emissions, a substantial yet highly uncertain part of which is from anthropogenically-modified peat swamp forests (PSFs) and mangroves. Here, we report that between 2001-2022 land-use change impacting PSFs and mangroves in SEA generate approximately 691.8±97.
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