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Science, 1999
The 56 Fe/ 54 Fe of Fe-bearing phases precipitated in sedimentary environments varies by 2.5 per mil (δ 56 Fe values of +0.9 to −1.6 per mil). In contrast, the 56 Fe/ 54 Fe of Fe-bearing phases in igneous rocks from Earth
Brian L. Beard +5 more
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The 56 Fe/ 54 Fe of Fe-bearing phases precipitated in sedimentary environments varies by 2.5 per mil (δ 56 Fe values of +0.9 to −1.6 per mil). In contrast, the 56 Fe/ 54 Fe of Fe-bearing phases in igneous rocks from Earth
Brian L. Beard +5 more
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Biological Homochirality and the Search for Extraterrestrial Biosignatures
Origins of Life and Evolution of Biospheres, 2022Most amino acids and sugar molecules occur in mirror, or chiral, images of each other, knowns as enantiomers. However, life on Earth is mostly homochiral: proteins contain almost exclusively L-amino acids, while only D-sugars appear in RNA and DNA.
M. Gleiser
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Biological Research For Nursing, 2009
The term health is commonplace in both everyday parlance and professional discourse. Unfortunately, the term has little objective specification, especially in physiologic terms. When critically examined, even time-honored terms such as homeostasis lack specific measurable referents.
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The term health is commonplace in both everyday parlance and professional discourse. Unfortunately, the term has little objective specification, especially in physiologic terms. When critically examined, even time-honored terms such as homeostasis lack specific measurable referents.
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SPIE Proceedings, 2005
As technology advances, we have more possibilities to search for past life, looking for biosignatures in the rock record. Even when these biosignatures can be chemical compounds, the irrevocable evidence of past life would be life itself preserved as fossils.
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As technology advances, we have more possibilities to search for past life, looking for biosignatures in the rock record. Even when these biosignatures can be chemical compounds, the irrevocable evidence of past life would be life itself preserved as fossils.
openaire +2 more sources
Astrobiology, 2003
A major goal of NASA's Origins Program is to find habitable planets around other stars and determine which might harbor life. Determining whether or not an extrasolar planet harbors life requires an understanding of what spectral features (i.e., biosignatures) might result from life's presence.
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A major goal of NASA's Origins Program is to find habitable planets around other stars and determine which might harbor life. Determining whether or not an extrasolar planet harbors life requires an understanding of what spectral features (i.e., biosignatures) might result from life's presence.
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Exoplanetary Biosignatures for Astrobiology
2018Since life evolved on our planet there have been subtle interplays between biology and Earth System Components (atmosphere-lithosphere-ocean-interior). Life, for example, can impact weathering rates which, in turn, influence climate stabilizing feedback cycles on Earth.
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Finding a biosignature for melancholic depression
Expert Review of Neurotherapeutics, 2012Melancholia is typified by features of psychomotor slowing, anxiety, appetite loss and sleep changes. It is usually observed in 20-30% of individuals meeting diagnostic criteria for major depressive disorder (MDD). There is currently no agreement on whether melancholic MDD represents a distinct entity defined by neurobiological as well as clinical ...
Claire V.A. Day, Leanne M. Williams
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Magnetic susceptibility as a biosignature
Journal of Earth Science, 2010INTRODUCTION One of the goals of geobiology is to understand the early evolution of life by examining the nature of the most primitive organisms, the environment in which they evolved, and the way in which they influenced that environment. Such endeavors assume that it is easy to differentiate the biotic from the abiotic, whether in ancient rocks on ...
Frank A. Corsetti +3 more
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2018
International audience; Life on the early Earth inhabited a planet whose environment was vastly different from the Earth of today. An anaerobic and hot early Earth was the birthplace of the first living cells but wide-spread small-scale physico-chemical diversity provided opportunities for a variety of specialists: alkalophiles, acidophiles, halophiles
Westall F. +2 more
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International audience; Life on the early Earth inhabited a planet whose environment was vastly different from the Earth of today. An anaerobic and hot early Earth was the birthplace of the first living cells but wide-spread small-scale physico-chemical diversity provided opportunities for a variety of specialists: alkalophiles, acidophiles, halophiles
Westall F. +2 more
openaire +2 more sources