Abiotic Sources of Molecular Hydrogen on Earth

Elements ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 19-24 ◽  
Author(s):  
Frieder Klein ◽  
Jesse D. Tarnas ◽  
Wolfgang Bach
Keyword(s):  
Molecular Hydrogen ◽  
Radioactive Decay ◽  
Life Forms ◽  
Microbial Ecosystems ◽  
Subsurface Environments ◽  
Wide Range ◽  
The Origin Of Life ◽  
Mechanical Breaking ◽  
Low Pressures ◽  
Silicate Rocks

The capacity for molecular hydrogen (H2) to hydrogenate oxygen and carbon is critical to the origin of life and represents the basis for all known life-forms. Major sources of H2 that strictly involve nonbiological processes and inorganic reactants include (1) the reduction of water during the oxidation of iron in minerals, (2) water splitting due to radioactive decay, (3) degassing of magma at low pressures, and (4) the reaction of water with surface radicals during mechanical breaking of silicate rocks. None of these processes seem to significantly affect the current global atmospheric budget of H2, yet there is substantial H2 cycling in a wide range of Earth’s subsurface environments, with multifaceted implications for microbial ecosystems.

Krypton 85 myocardial blood flow: precordial scintillation versus coronary sinus sampling

1965 ◽  
Vol 209 (4) ◽  
pp. 705-710 ◽  
Author(s):  
Michael D. Klein ◽  
Lawrence S. Cohen ◽  
Richard Gorlin
Keyword(s):  
Blood Flow ◽  
Myocardial Blood Flow ◽  
Coronary Sinus ◽  
Human Subjects ◽  
Radioactive Decay ◽  
Empirical Correction ◽  
Wide Range ◽  
Actual Flow ◽  
Flow Through ◽  
High Degree

Myocardial blood flow in human subjects was assessed by comparative simultaneous measurement of krypton 85 radioactive decay from coronary sinus and precordial scintillation. Empirical correction of postclearance background from precordial curves yielded a high degree of correlation between flows derived from the two sampling sites (r = .889, P < .001). Comparison of left and right coronary flows in nine subjects revealed similarity in flow through the two vessels over a wide range of actual flow values (r = .945, P < .001).

scholarly journals A COMPARATIVE ANATOMICAL CHARACTERISTICS OF THE STEMS OF CLIMBING PLANTS IN ARALAM WILD LIFE SANCTUARY, KANNUR

2016 ◽  
Vol 3 (1) ◽  
pp. 37-44
Author(s):  
Prasanth K.P ◽  
Sekaran S
Keyword(s):  
Secondary Growth ◽  
Life Forms ◽  
Tinospora Cordifolia ◽  
Piper Nigrum ◽  
Supporting Cells ◽  
Anatomical Structures ◽  
Climbing Plants ◽  
Plant Life Forms ◽  
Wide Range ◽  
Storage Parenchyma

Climbing plants differ from self-supporting plants, such as shrubs and trees, in a range of characteristics. The most notable is the mechanical properties of the stem Comparison of the differentiated anatomical structures recorded in ten species of the climbing plants. The plants selected for the present study are Ampelocissus latifolia, (Vitaceae), Lygodium flexuosum (Lygodiaceae), Centrosema virginianum (Fabaceae), Tinospora cordifolia, (Menispermaceae), Wattakakka volubilis (Asclepiadaceae) Cyclea peltata (Menispermaceae), Calycopteris floribunda (Combretaceae) Pothos scandens (Araceae) Ipomoea separia (Convolvulaceae) and Piper nigrum (Piperaceae). The stems of climbing plants are characterized by the scarcity of supporting cells (fibers) and an increase in the diameter of the xylem vessels. The study con firms that they show a greater diversity of organization than other plant life forms. This anatomical radiation couldprobably not exist without the achievement of a wide range of secondary growth processes. Many dicotyledons, notably those with a climbing habit, show interesting secondary structure which differs from the more usual type described, therefore, sometimes termed anomalous. The variant secondary growth isparticularly widespread in tropical climbers. It is speculated that variant growth can increase stem flexibility, protect the phloem, increase storage parenchyma, aid in clinging to supports, limit physical disruption of vascular tissues during twisting and bending, and promote wound healing after girdling.

scholarly journals Cosmic Ray Induced Photodestruction of Interstellar Molecules

1989 ◽  
Vol 120 ◽  
pp. 32-37
Author(s):  
R. Gredel ◽  
S. Lepp ◽  
A. Dalgarno ◽  
E. Herbst
Keyword(s):  
Molecular Hydrogen ◽  
Cosmic Ray ◽  
Impact Excitation ◽  
Interstellar Molecules ◽  
Secondary Electrons ◽  
Interstellar Clouds ◽  
Wide Range ◽  
Ultraviolet Photons ◽  
The Impact ◽  
Equilibrium Chemical

AbstractUltraviolet photons are created in the interior of dense interstellar clouds by the impact excitation of molecular hydrogen by secondary electrons generated by cosmic ray ionization. The resulting photodissociation and photoionization rates of a wide range of interstellar molecules are calculated. The effects on the equilibrium chemical composition of dense clouds are briefly discussed.

The Origin of Life Was Brought to You in Part by Silicate Rocks

2017 ◽  
pp. 9-27
Author(s):  
Christina De La Rocha ◽  
Daniel J. Conley
Keyword(s):  
Origin Of Life ◽  
The Origin Of Life ◽  
Silicate Rocks

scholarly journals Iron Ion Particle Radiation Resistance of Dried Colonies of Cryomyces antarcticus Embedded in Martian Regolith Analogues

Life ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 306
Author(s):  
Lorenzo Aureli ◽  
Claudia Pacelli ◽  
Alessia Cassaro ◽  
Akira Fujimori ◽  
Ralf Moeller ◽  
...  
Keyword(s):  
Extreme Environments ◽  
Life Forms ◽  
Culture Collection ◽  
Dna Integrity ◽  
Martian Surface ◽  
Particle Radiation ◽  
Shallow Subsurface ◽  
Subsurface Environments ◽  
High Doses ◽  
Martian Regolith

Among the celestial bodies in the Solar System, Mars currently represents the main target for the search for life beyond Earth. However, its surface is constantly exposed to high doses of cosmic rays (CRs) that may pose a threat to any biological system. For this reason, investigations into the limits of resistance of life to space relevant radiation is fundamental to speculate on the chance of finding extraterrestrial organisms on Mars. In the present work, as part of the STARLIFE project, the responses of dried colonies of the black fungus Cryomyces antarcticus Culture Collection of Fungi from Extreme Environments (CCFEE) 515 to the exposure to accelerated iron (LET: 200 keV/μm) ions, which mimic part of CRs spectrum, were investigated. Samples were exposed to the iron ions up to 1000 Gy in the presence of Martian regolith analogues. Our results showed an extraordinary resistance of the fungus in terms of survival, recovery of metabolic activity and DNA integrity. These experiments give new insights into the survival probability of possible terrestrial-like life forms on the present or past Martian surface and shallow subsurface environments.

SYNCHRONIZATION PHENOMENA IN PROTOCELL MODELS

2008 ◽  
Vol 03 (01n02) ◽  
pp. 325-342 ◽  
Author(s):  
ALESSANDRO FILISETTI ◽  
ROBERTO SERRA ◽  
TIMOTEO CARLETTI ◽  
IRENE POLI ◽  
MARCO VILLANI
Keyword(s):  
Origin Of Life ◽  
Life Forms ◽  
New Drugs ◽  
Simplified Models ◽  
The Origin Of Life ◽  
Modelling Approach

This work aims to consider simplified models of protocells in order to describe their general behaviors. The advantage of the modelling approach is that the early protocells of life-forms on Earth are not reproduced in the present time. However, the problem is considered as a right track to understand the origin of life as well as to work with more objective synthesis of new drugs.

scholarly journals Cognitive niche

2020 ◽  
Vol 11 (1) ◽  
pp. 64-70
Author(s):  
Đorđe Petronić ◽  
Igor Vujović
Keyword(s):  
Charles Darwin ◽  
Life Forms ◽  
Human Intelligence ◽  
Theory Of Evolution ◽  
Cognitive Niche ◽  
Human Habitat ◽  
Science Philosophy ◽  
The Origin Of Life ◽  
The Difference ◽  
Survival Mode

In a joint publication with Alfred Russell Wallace, Charles Darwin presented the theory which stated that all life forms were developed by natural selection in which the fight for survival had the effect similar to artificial intelligence applied to selective breeding. Despite a coincidence of views concerning the origin of life, these two scientists had their disagreements. Wallace argued that intelligence could have never arisen through the process of natural adaptation, but rather as a consequence of intelligent design. On the other hand, Darwin insisted that human intelligence could only be explained by the theory of evolution. This difference in point of views on the matter is a manifestation of the difference in the efforts to answer the question: "Why are people so intelligent?" In this context, the main aim of the study is to present a literature review concerning evolutionary psychology and to provide an explanation of the evolution of human intelligence. In other words, the study seeks to explain why people are able to accomplish such intellectual exploits as the ones found in mathematics, science, philosophy, law, etc., bearing in mind that such abilities or talents cannot be found in the original human habitat. The results have showed that evolutionary psychologists consider humans to be so intelligent due to the fact that they have evolved to fill the "cognitive niche". The cognitive niche is a survival mode characterized by managing the environment through mediating cognition and social cooperation.

scholarly journals Turbulence explains the accelerations of an eagle in natural flight

2021 ◽  
Vol 118 (23) ◽  
pp. e2102588118
Author(s):  
Kasey M. Laurent ◽  
Bob Fogg ◽  
Tobias Ginsburg ◽  
Casey Halverson ◽  
Michael J. Lanzone ◽  
...  
Keyword(s):  
Large Scale ◽  
Power Spectra ◽  
Life Forms ◽  
Flight Behavior ◽  
Avian Behavior ◽  
Avian Flight ◽  
Turbulent Environments ◽  
Wide Range ◽  
In The Wild ◽  
Atmospheric Phenomena

Turbulent winds and gusts fluctuate on a wide range of timescales from milliseconds to minutes and longer, a range that overlaps the timescales of avian flight behavior, yet the importance of turbulence to avian behavior is unclear. By combining wind speed data with the measured accelerations of a golden eagle (Aquila chrysaetos) flying in the wild, we find evidence in favor of a linear relationship between the eagle’s accelerations and atmospheric turbulence for timescales between about 1/2 and 10 s. These timescales are comparable to those of typical eagle behaviors, corresponding to between about 1 and 25 wingbeats, and to those of turbulent gusts both larger than the eagle’s wingspan and smaller than large-scale atmospheric phenomena such as convection cells. The eagle’s accelerations exhibit power spectra and intermittent activity characteristic of turbulence and increase in proportion to the turbulence intensity. Intermittency results in accelerations that are occasionally several times stronger than gravity, which the eagle works against to stay aloft. These imprints of turbulence on the bird’s movements need to be further explored to understand the energetics of birds and other volant life-forms, to improve our own methods of flying through ceaselessly turbulent environments, and to engage airborne wildlife as distributed probes of the changing conditions in the atmosphere.

scholarly journals Potassium isotopic variability and implications for <sup>40</sup>K-based geochronology

2020 ◽  
Author(s):  
Leah E. Morgan
Keyword(s):  
Neutron Fluence ◽  
Radioactive Decay ◽  
Mean Value ◽  
Decay Constants ◽  
Wide Range ◽  
The Mean ◽  
Precision And Accuracy ◽  
Ar Geochronology ◽  
Isotopic Measurements ◽  
Silicate Materials

Abstract. 40Ar/39Ar and K-Ar geochronology assume that 40K/K values are invariant among the sample of interest, the co-irradiated neutron fluence monitor (standard), and the material used to measure decay constants. Until recently, this assumption was reasonable due to the small K isotope (41K, 40K, 39K) variability found in many terrestrial samples and the negligible effect of any variation relative to the precision of the determined age. The recent discovery of measurable δ41K variability in terrestrial samples now questions this assumption. Although δ41K values for some neutron fluence monitors have now been reported, potassium isotopes are not routinely measured on samples dated by the 40Ar/39Ar method even though a wide range of silicate materials were found to vary by > 2.5 ‰. Further, the 40K decay constants used in 40Ar/39Ar geochronology are based on activity counting of radioactive decay in K-rich salts. These salts have not been measured for δ41K, yet evaporites have been shown to vary by > 1 ‰ from the mean value of silicates. The potential effects of δ41K variability on 40Ar/39Ar ages are illustrated using the case of the ca. 28.2 Ma Fish Canyon sanidine (FCs) and the ca. 99 Ma Mt. Dromedary Biotite (GA-1550). If the two standards have δ41K values as measured and the material used to determine decay constants is appropriately represented by δ41K of evaporites, the age of FCs is underestimated by ca. 7 ka (0.25 ‰). Although this is a small effect, such bias is becoming important as the analytical precision and accuracy of isotopic measurements and calculation of 40Ar/39Ar ages continue to improve.

scholarly journals LIFE AS WE DO NOT KNOW IT

2021 ◽  
Author(s):  
soumya banerjee
Keyword(s):  
Information Processing ◽  
Computational Model ◽  
Origin Of Life ◽  
Critical Role ◽  
Life Forms ◽  
Living Systems ◽  
Computational Simulations ◽  
The Origin Of Life ◽  
Carbon Based

Information plays a critical role in complex biologicalsystems. This article proposes a role for information processing in questions around the origin of life and suggests how computational simulations may yield insights into questions related to the origin of life. Such a computational model of the origin of life would unify thermodynamics with information processing and we would gain an appreciation of why proteins and nucleotides evolved as the substrate of computation andinformation processing in living systems that we see on Earth. Answers to questions like these may give us insights into noncarbon based forms of life that we could search for outside Earth. I hypothesize that carbon-based life forms are only one amongst a continuum of life-like systems in the universe.Investigations into the role of computational substrates that allow information processing is important and could yield insights into:1) novel non-carbon based computational substrates thatmay have “life-like” properties, and2) how life may have actually originated from non-life onEarth. Life may exist as a continuum between non-life and life and we may have to revise our notion of life and how common it is in the universe.Looking at life or life-like phenomena through the lens ofinformation theory may yield a broader view of life.

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