keyword
MENU ▼
Read by QxMD icon Read
search

Astrobiology

keyword
https://www.readbyqxmd.com/read/28072548/conference-report-biosignature-preservation-and-detection-in-mars-analog-environments
#1
Lindsay Hays, David Beaty
The Conference on Biosignature Preservation and Detection in Mars Analog Environments held in May 2016 brought together scientists to discuss microbial biosignatures in Mars analog habitable environments. Five analog environments were discussed: (1) hydrothermal spring systems, (2) subaqueous environments, (3) subaerial environments, (4) subsurface environments, and (5) iron-rich systems. This paper details the major messages that resulted from the discussions and will be followed by a review paper that adds significant detail from the published literature and interpretations from the writing committee of the workshop for future research and application to astrobiological exploration missions...
January 10, 2017: Astrobiology
https://www.readbyqxmd.com/read/28068148/element-cycling-and-energy-flux-responses-in-ecosystem-simulations-conducted-at-the-chinese-lunar-palace-1
#2
Chen Dong, Yuming Fu, Beizhen Xie, Minjuan Wang, Hong Liu
Bioregenerative life-support systems (BLSS) address interactions between organisms and their environment as an integrated system through the study of factors that regulate the pools and fluxes of materials and energy through ecological systems. As a simple model, using BLSS is very important in the investigation of element cycling and energy flux for sustainable development on Earth. A 105-day experiment with a high degree of closure was carried out in this system from February to May, 2014, with three volunteers...
January 9, 2017: Astrobiology
https://www.readbyqxmd.com/read/28051326/g-equivalent-acceleration-tolerance-in-the-eutardigrade-species-hypsibius-dujardini
#3
Tarushika Vasanthan, Lorea Alejaldre, Jessica Hider, Shreya Patel, Nabiha Husain, Bavithra Umapathisivam, Jonathon Stone
Tardigrades are microscopic organisms renowned for their ability to survive extreme environmental conditions. Tardigrade extreme-tolerance research has centered on the ability to withstand desiccation, low and high temperatures, and high hydrostatic pressure and radiation levels. Tardigrade tolerance to hypergravity, however, has yet to be described. We used the eutardigrade species Hypsibius dujardini to investigate short-term tolerance to g-equivalent accelerations (i.e., mimicking g-forces). Data obtained from specimens centrifuged between 3421g and 16,060g for 1 min inclusively reveal tolerance in an acceleration-dependent relation, with lower survivorship and egg production at higher accelerations...
January 4, 2017: Astrobiology
https://www.readbyqxmd.com/read/28026990/a-possible-role-for-stochastic-astrophysical-ionizing-radiation-events-in-the-systematic-disparity-between-molecular-and-fossil-dates
#4
Adrian L Melott
Major discrepancies have been noted for some time between fossil ages and molecular divergence dates for a variety of taxa. Recently, systematic trends within avian clades have been uncovered. The trends show that the disparity is much larger for mitochondrial DNA than for nuclear DNA, also that it is larger for crown fossil dates than stem fossil dates. It has been argued that this pattern is largely inconsistent with incompleteness of the fossil record as the principal driver of the disparity. A case is presented that, given the expected mutations from a fluctuating background of astrophysical radiation from such sources as supernovae, the rate of molecular clocks is variable and should increase back to a few million years, before returning to the long-term average rate...
December 27, 2016: Astrobiology
https://www.readbyqxmd.com/read/28001448/following-the-interstellar-history-of-carbon-from-the-interiors-of-stars-to-the-surfaces-of-planets
#5
L M Ziurys, D T Halfen, W Geppert, Y Aikawa
The chemical history of carbon is traced from its origin in stellar nucleosynthesis to its delivery to planet surfaces. The molecular carriers of this element are examined at each stage in the cycling of interstellar organic material and their eventual incorporation into solar system bodies. The connection between the various interstellar carbon reservoirs is also examined. Carbon has two stellar sources: supernova explosions and mass loss from evolved stars. In the latter case, the carbon is dredged up from the interior and then ejected into a circumstellar envelope, where a rich and unusual C-based chemistry occurs...
December 2016: Astrobiology
https://www.readbyqxmd.com/read/27956875/self-assembling-iron-oxyhydroxide-oxide-tubular-structures-laboratory-grown-and-field-examples-from-rio-tinto
#6
Laura M Barge, Silvana S S Cardoso, Julyan H E Cartwright, Ivria J Doloboff, Erika Flores, Elena Macías-Sánchez, C Ignacio Sainz-Díaz, Pablo Sobrón
Rio Tinto in southern Spain has become of increasing astrobiological significance, in particular for its similarity to environments on early Mars. We present evidence of tubular structures from sampled terraces in the stream bed at the source of the river, as well as ancient, now dry, terraces. This is the first reported finding of tubular structures in this particular environment. We propose that some of these structures could be formed through self-assembly via an abiotic mechanism involving templated precipitation around a fluid jet, a similar mechanism to that commonly found in so-called chemical gardens...
November 2016: Proceedings. Mathematical, Physical, and Engineering Sciences
https://www.readbyqxmd.com/read/27925795/oxidants-at-the-surface-of-mars-a-review-in-light-of-recent-exploration-results
#7
J Lasne, A Noblet, C Szopa, R Navarro-González, M Cabane, O Poch, F Stalport, P François, S K Atreya, P Coll
In 1976, the Viking landers carried out the most comprehensive search for organics and microbial life in the martian regolith. Their results indicate that Mars' surface is lifeless and, surprisingly, depleted in organics at part-per-billion levels. Several biology experiments on the Viking landers gave controversial results that have since been explained by the presence of oxidizing agents on the surface of Mars. These oxidants may degrade abiotic or biological organics, resulting in their nondetection in the regolith...
December 2016: Astrobiology
https://www.readbyqxmd.com/read/27912029/how-to-establish-a-bioregenerative-life-support-system-for-long-term-crewed-missions-to-the-moon-or-mars
#8
Yuming Fu, Leyuan Li, Beizhen Xie, Chen Dong, Mingjuan Wang, Boyang Jia, Lingzhi Shao, Yingying Dong, Shengda Deng, Hui Liu, Guanghui Liu, Bojie Liu, Dawei Hu, Hong Liu
To conduct crewed simulation experiments of bioregenerative life support systems on the ground is a critical step for human life support in deep-space exploration. An artificial closed ecosystem named Lunar Palace 1 was built through integrating efficient higher plant cultivation, animal protein production, urine nitrogen recycling, and bioconversion of solid waste. Subsequently, a 105-day, multicrew, closed integrative bioregenerative life support systems experiment in Lunar Palace 1 was carried out from February through May 2014...
December 2016: Astrobiology
https://www.readbyqxmd.com/read/27912028/formation-and-persistence-of-brine-on-mars-experimental-simulations-throughout-the-diurnal-cycle-at-the-phoenix-landing-site
#9
E Fischer, G M Martínez, N O Rennó
In the last few years, water ice and salts capable of melting this ice and producing liquid saline water (brine) have been detected on Mars. Moreover, indirect evidence for brine has been found in multiple areas of the planet. Here, we simulate full diurnal cycles of temperature and atmospheric water vapor content at the Phoenix landing site for the first time and show experimentally that, in spite of the low Mars-like chamber temperature, brine forms minutes after the ground temperature exceeds the eutectic temperature of salts in contact with water ice...
December 2016: Astrobiology
https://www.readbyqxmd.com/read/27905827/modeling-pn2-through-geological-time-implications-for-planetary-climates-and-atmospheric-biosignatures
#10
E E Stüeken, M A Kipp, M C Koehler, E W Schwieterman, B Johnson, R Buick
Nitrogen is a major nutrient for all life on Earth and could plausibly play a similar role in extraterrestrial biospheres. The major reservoir of nitrogen at Earth's surface is atmospheric N2, but recent studies have proposed that the size of this reservoir may have fluctuated significantly over the course of Earth's history with particularly low levels in the Neoarchean-presumably as a result of biological activity. We used a biogeochemical box model to test which conditions are necessary to cause large swings in atmospheric N2 pressure...
December 2016: Astrobiology
https://www.readbyqxmd.com/read/27901343/colonization-of-snow-by-microorganisms-as-revealed-using-miniature-raman-spectrometers-possibilities-for-detecting-carotenoids-of-psychrophiles-on-mars
#11
Jan Jehlička, Adam Culka, Linda Nedbalová
We tested the potential of a miniaturized Raman spectrometer for use in field detection of snow algae pigments. A miniature Raman spectrometer, equipped with an excitation laser at 532 nm, allowed for the detection of carotenoids in cells of Chloromonas nivalis and Chlamydomonas nivalis at different stages of their life cycle. Astaxanthin, the major photoprotective pigment, was detected in algal blooms originating in snows at two alpine European sites that differed in altitude (Krkonoše Mts., Czech Republic, 1502 m a...
December 2016: Astrobiology
https://www.readbyqxmd.com/read/27893284/biomarkers-and-metabolic-patterns-in-the-sediments-of-evolving-glacial-lakes-as-a-proxy-for-planetary-lake-exploration
#12
Víctor Parro, Yolanda Blanco, Fernando Puente-Sánchez, Luis A Rivas, Mercedes Moreno-Paz, Alex Echeverría, Guillermo Chong-Díaz, Cecilia Demergasso, Nathalie A Cabrol
Oligotrophic glacial lakes in the Andes Mountains serve as models to study the effects of climate change on natural biological systems. The persistent high UV regime and evolution of the lake biota due to deglaciation make Andean lake ecosystems potential analogues in the search for life on other planetary bodies. Our objective was to identify microbial biomarkers and metabolic patterns that represent time points in the evolutionary history of Andean glacial lakes, as these may be used in long-term studies as microscale indicators of climate change processes...
November 28, 2016: Astrobiology
https://www.readbyqxmd.com/read/27871132/aspergillus-penicillioides-differentiation-and-cell-division-at-0-585-water-activity
#13
Andrew Stevenson, Philip G Hamill, Callum J O'Kane, Gerhard Kminek, John D Rummel, Mary A Voytek, Jan Dijksterhuis, John E Hallsworth
Water availability acts as the most-stringent constraint for life on Earth. Thus, understanding the water relations of microbial extremophiles is imperative to our ability to increase agricultural productivity (e.g., by enhancing the processing and turnover of dead organic matter in soils of arid regions); reduce human exposure to mycotoxins in buildings and our food-supply chain; prevent the spoilage of foods/animal feeds, books, museum specimens and artworks; and better control microbiology of industrial fermentations...
November 21, 2016: Environmental Microbiology
https://www.readbyqxmd.com/read/27870586/organic-matter-detection-on-mars-by-pyrolysis-ftir-an-analysis-of-sensitivity-and-mineral-matrix-effects
#14
Peter R Gordon, Mark A Sephton
Returning samples from Mars will require an effective method to assess and select the highest-priority geological materials. The ideal instrument for sample triage would be simple in operation, limited in its demand for resources, and rich in produced diagnostic information. Pyrolysis-Fourier infrared spectroscopy (pyrolysis-FTIR) is a potentially attractive triage instrument that considers both the past habitability of the sample depositional environment and the presence of organic matter that may reflect actual habitation...
November 2016: Astrobiology
https://www.readbyqxmd.com/read/27870585/another-earth-2-0-not-so-fast
#15
Dirk Schulze-Makuch, Edward Guinan
The number of confirmed exoplanets now exceeds 3000, with an additional nearly 5000 exoplanet candidates awaiting confirmation in the NASA Exoplanet Archive ( 2016 ). Nearly weekly we hear about the detection of a new exoplanet similar in mass to Earth and located in the so-called habitable zone around its host star. The excitement is understandable given our desire to find a second Earth. However, the excitement should not lead to an over-interpretation of the findings, because the claim can only be to have some crude similarity to Earth based on a few selected geophysical parameters...
November 2016: Astrobiology
https://www.readbyqxmd.com/read/27870584/follow-the-carbon-isotopic-labeling-studies-of-early-earth-aerosol
#16
Raea K Hicks, Douglas A Day, Jose L Jimenez, Margaret A Tolbert
Despite the faint young Sun, early Earth might have been kept warm by an atmosphere containing the greenhouse gases CH4 and CO2 in mixing ratios higher than those found on Earth today. Laboratory and modeling studies suggest that an atmosphere containing these trace gases could lead to the formation of organic aerosol haze due to UV photochemistry. Chemical mechanisms proposed to explain haze formation rely on CH4 as the source of carbon and treat CO2 as a source of oxygen only, but this has not previously been verified experimentally...
November 2016: Astrobiology
https://www.readbyqxmd.com/read/27870583/organic-matter-responses-to-radiation-under-lunar-conditions
#17
Richard Matthewman, Ian A Crawford, Adrian P Jones, Katherine H Joy, Mark A Sephton
Large bodies, such as the Moon, that have remained relatively unaltered for long periods of time have the potential to preserve a record of organic chemical processes from early in the history of the Solar System. A record of volatiles and impactors may be preserved in buried lunar regolith layers that have been capped by protective lava flows. Of particular interest is the possible preservation of prebiotic organic materials delivered by ejected fragments of other bodies, including those originating from the surface of early Earth...
November 2016: Astrobiology
https://www.readbyqxmd.com/read/27870556/twenty-species-of-hypobarophilic-bacteria-recovered-from-diverse-soils-exhibit-growth-under-simulated-martian-conditions-at-0-7%C3%A2-kpa
#18
Andrew C Schuerger, Wayne L Nicholson
Bacterial growth at low pressure is a new research area with implications for predicting microbial activity in clouds and the bulk atmosphere on Earth and for modeling the forward contamination of planetary surfaces like Mars. Here, we describe experiments on the recovery and identification of 20 species of bacterial hypobarophiles (def., growth under hypobaric conditions of approximately 1-2 kPa) in 10 genera capable of growth at 0.7 kPa. Hypobarophilic bacteria, but not archaea or fungi, were recovered from diverse soils, and high numbers of hypobarophiles were recovered from Arctic and Siberian permafrost soils...
December 2016: Astrobiology
https://www.readbyqxmd.com/read/27870548/onboard-science-insights-and-vehicle-dynamics-from-scale-model-trials-of-the-titan-mare-explorer-time-capsule-at-laguna-negra-chile
#19
Ralph D Lorenz, Nathalie A Cabrol
A scale model of the proposed Titan Mare Explorer capsule was deployed at the Planetary Lake Lander field site at Laguna Negra, Chile. The tests served to calibrate models of wind-driven drift of the capsule and to understand its attitude motion in the wave field, as well as to identify dynamic and acoustic signatures of shoreline approach. This information enables formulation of onboard trigger criteria for near-shore science data acquisition. Key Words: Titan-Vehicle dynamics-Science autonomy-Lake. Astrobiology 17, xxx-xxx...
November 21, 2016: Astrobiology
https://www.readbyqxmd.com/read/27827540/meteorites-and-the-rna-world-a-thermodynamic-model-of-nucleobase-synthesis-within-planetesimals
#20
Ben K D Pearce, Ralph E Pudritz
The possible meteorite parent body origin of Earth's pregenetic nucleobases is substantiated by the guanine (G), adenine (A), and uracil (U) measured in various meteorites. Cytosine (C) and thymine (T), however, are absent in meteorites, making the emergence of an RNA and later RNA/DNA/protein world problematic. We investigated the meteorite parent body (planetesimal) origin of all nucleobases by computationally modeling 18 reactions that potentially contribute to nucleobase formation in such environments. Out of this list, we identified the two most important reactions for each nucleobase and found that these involve small molecules such as HCN, CO, NH3, and water that ultimately arise from the protoplanetary disks in which planetesimals are built...
November 2016: Astrobiology
keyword
keyword
72461
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"