Non-intrusive probing of fluid mixing with double diffusion layers brings insight into its origin and evolution

Scilight ◽  
2018 ◽  
Vol 2018 (47) ◽  
pp. 470001 ◽  
Author(s):  
Drew DeJarnette
Keyword(s):  
Double Diffusion ◽  
Fluid Mixing ◽  
Origin And Evolution ◽  
Diffusion Layers ◽  
Insight Into

scholarly journals Remotely distinguishing and mapping endogenic water on the Moon

2017 ◽  
Vol 375 (2094) ◽  
pp. 20150391 ◽  
Author(s):  
Rachel L. Klima ◽  
Noah E. Petro
Keyword(s):  
Solar Wind ◽  
Spatial Distribution ◽  
Solar System ◽  
The Moon ◽  
Testing Hypotheses ◽  
Origin And Evolution ◽  
Lunar Interior ◽  
Geological Features ◽  
Insight Into

Water and/or hydroxyl detected remotely on the lunar surface originates from several sources: (i) comets and other exogenous debris; (ii) solar-wind implantation; (iii) the lunar interior. While each of these sources is interesting in its own right, distinguishing among them is critical for testing hypotheses for the origin and evolution of the Moon and our Solar System. Existing spacecraft observations are not of high enough spectral resolution to uniquely characterize the bonding energies of the hydroxyl molecules that have been detected. Nevertheless, the spatial distribution and associations of H, OH − or H 2 O with specific lunar lithologies provide some insight into the origin of lunar hydrous materials. The global distribution of OH − /H 2 O as detected using infrared spectroscopic measurements from orbit is here examined, with particular focus on regional geological features that exhibit OH − /H 2 O absorption band strengths that differ from their immediate surroundings. This article is part of the themed issue ‘The origin, history and role of water in the evolution of the inner Solar System’.

scholarly journals Origin and evolution of developmental enhancers in the mammalian neocortex

2016 ◽  
Vol 113 (19) ◽  
pp. E2617-E2626 ◽  
Author(s):  
Deena Emera ◽  
Jun Yin ◽  
Steven K. Reilly ◽  
Jake Gockley ◽  
James P. Noonan
Keyword(s):  
De Novo ◽  
Regulatory Elements ◽  
Evolutionary Constraint ◽  
Regulatory Sequences ◽  
En Bloc ◽  
Origin And Evolution ◽  
Stem Lineage ◽  
Coexpressed Genes ◽  
Human And Mouse ◽  
Insight Into

Morphological innovations such as the mammalian neocortex may involve the evolution of novel regulatory sequences. However, de novo birth of regulatory elements active during morphogenesis has not been extensively studied in mammals. Here, we use H3K27ac-defined regulatory elements active during human and mouse corticogenesis to identify enhancers that were likely active in the ancient mammalian forebrain. We infer the phylogenetic origins of these enhancers and find that ∼20% arose in the mammalian stem lineage, coincident with the emergence of the neocortex. Implementing a permutation strategy that controls for the nonrandom variation in the ages of background genomic sequences, we find that mammal-specific enhancers are overrepresented near genes involved in cell migration, cell signaling, and axon guidance. Mammal-specific enhancers are also overrepresented in modules of coexpressed genes in the cortex that are associated with these pathways, notably ephrin and semaphorin signaling. Our results also provide insight into the mechanisms of regulatory innovation in mammals. We find that most neocortical enhancers did not originate by en bloc exaptation of transposons. Young neocortical enhancers exhibit smaller H3K27ac footprints and weaker evolutionary constraint in eutherian mammals than older neocortical enhancers. Based on these observations, we present a model of the enhancer life cycle in which neocortical enhancers initially emerge from genomic background as short, weakly constrained “proto-enhancers.” Many proto-enhancers are likely lost, but some may serve as nucleation points for complex enhancers to evolve.

scholarly journals Catalytic/Protective Properties of Martian Minerals and Implications for Possible Origin of Life on Mars

Life ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 56 ◽  
Author(s):  
Teresa Fornaro ◽  
Andrew Steele ◽  
John Brucato
Keyword(s):  
Organic Compounds ◽  
Building Blocks ◽  
Life Forms ◽  
Degradation Mechanisms ◽  
Protective Properties ◽  
Origin And Evolution ◽  
Life On Mars ◽  
Insight Into ◽  
Shed Light

Minerals might have played critical roles for the origin and evolution of possible life forms on Mars. The study of the interactions between the “building blocks of life” and minerals relevant to Mars mineralogy under conditions mimicking the harsh Martian environment may provide key insight into possible prebiotic processes. Therefore, this contribution aims at reviewing the most important investigations carried out so far about the catalytic/protective properties of Martian minerals toward molecular biosignatures under Martian-like conditions. Overall, it turns out that the fate of molecular biosignatures on Mars depends on a delicate balance between multiple preservation and degradation mechanisms, often regulated by minerals, which may take place simultaneously. Such a complexity requires more efforts in simulating realistically the Martian environment in order to better inspect plausible prebiotic pathways and shed light on the nature of the organic compounds detected both in meteorites and on the surface of Mars through in situ analysis.

scholarly journals Structural and Morphogenetic Complexity of Fluorapatite-Gelatine Nanocomposites

2014 ◽  
Vol 70 (a1) ◽  
pp. C595-C595
Author(s):  
Elena Rosseeva ◽  
Paul Simon ◽  
Rüdiger Kniep
Keyword(s):  
Crystallization Process ◽  
Functional Materials ◽  
Double Diffusion ◽  
Nanocomposite Materials ◽  
Self Organization ◽  
Biomimetic Systems ◽  
Composite Formation ◽  
Protein Molecules ◽  
Main Components ◽  
Insight Into

The most fascinating natural examples of nanocomposite materials are represented by so-called biominerals, acting as functional materials in living systems. In particular, apatite-organic (protein) nanocomposites are the main components of bone and teeth hard tissues of vertebrates (including humans) [1]. Biomimetic systems provide an excellent possibility to get deeper insight into the fundamental principles of structuring, organization and formation of biominerals. Therefore, our investigations are focused on biomimetic fluorapatite-gelatine nanocomposites grown by double-diffusion in gelatine gels [2]. In the gelatine gel protein molecules interact with the ions in solution in such a way that they provide nucleation positions for nano apatite and, in this way, give rise to dramatic processes of self-organization and hierarchical composite formation. Numerous experimental observations (by means of XRD, SEM, HRTEM, EH, etc.) together with atomistic computer simulations reveal the material to be best described as a mosaic-dominated nanocomposite superstructure. Furthermore intrinsic electric dipole fields, generated by a non-classical crystallization process of composite nanoboards, cause the integration of a meso/macroscopic pattern of gelatine microfibrils into the superstructure matrix and govern morphogenetic process of fluorapatite-gelatine nanocomposites [3].

scholarly journals New Clues to Reveal Origins of Hot- and Warm-Jupiter: Mutual Occurrence Rate of Hot Jupiter，Warm Jupiter and Cold Jupiter

2021 ◽  
Author(s):  
Xiangning Su ◽  
Hui Zhang ◽  
Jilin Zhou
Keyword(s):  
Effective Temperature ◽  
Giant Planets ◽  
Detection Methods ◽  
Occurrence Rate ◽  
Origin And Evolution ◽  
History Of ◽  
Stellar Properties ◽  
Insight Into ◽  
Hot Jupiter

Abstract Many works based on the correlations between the occurrence rate of various giant planets and stellar properties of their hosts have provided clues revealing planetary formation processes. However, few researches have focused on the mutual occurrence rate of different type of planets and their dependency upon the stellar properties, which may help to provide an insight into the dynamics evolution history of planetary systems. To investigate the mutual occurrence rates, first we define three types of giant planets, i.e. cold Jupiter(CJ), warm Jupiter(WJ) and hot Jupiter(HJ), according to their position normalized by the snow-line in the system, ap > asnow, 0:1asnow < ap ≤ asnow and ap ≤ 0:1asnow, respectively. Then, we derive their occurrence rates(ηHJ,ηwJ,ηcJ) considering completeness correction caused by different detection methods (RV and transit) and surveys (HARPS& CORALIE and Kepler). Finally, we investigate the correlation between the relative occurrence rates, i.e. ηcJ/ηwJ or ηwJ/ηHJ, and various stellar properties, e.g. stellar metallicity and effective temperature Teff . We find that ηWJ from RV and transit surveys show a similar increasing trend with the increasing stellar effective temperature when Teff ≤ 6100K. While ηcJ from RV samples is almost flat within Teff in (4600K;6100K], and ηHJ from transit samples is increasing with increasing stellar effective temperature within 3600K < Te f f < 7100K. Further more, we find that the mutual occurrence rate between CJ and WJ, i.e. ηcJ/ηwJ , shows a decreasing trend with the increasing stellar effective temperature. In contrary, the ratio ηwJ/ηHJ is reversely depends on the stellar effective temperature. After a series of consistency tests, our results suggest the in-situ hypothesis can be excluded from the formation process of both WJ and HJ. However, the origin and evolution history of HJ may be quite different from that of WJ.

scholarly journals SSR marker variations in Brassica species provide insight into the origin and evolution of Brassica amphidiploids

Hereditas ◽  
2017 ◽  
Vol 155 (1) ◽  
Author(s):  
Ajay Kumar Thakur ◽  
Kunwar Harendra Singh ◽  
Lal Singh ◽  
Joghee Nanjundan ◽  
Yasin Jeshima Khan ◽  
...  
Keyword(s):  
Ssr Marker ◽  
Brassica Species ◽  
Origin And Evolution ◽  
Insight Into

scholarly journals 3.10 Mariner Mission to Encke 1980

1976 ◽  
Vol 31 ◽  
pp. 346-355 ◽  
Author(s):  
C. M. Yeates ◽  
K. T. Nock ◽  
R. L. Newburn
Keyword(s):  
Solar System ◽  
Early Stage ◽  
Early Period ◽  
Atmospheric Effects ◽  
Formation Processes ◽  
Small Bodies ◽  
Origin And Evolution ◽  
Great Insight ◽  
Insight Into ◽  
Actual Formation

The planetary program has always been conducted with the hope that the results would reveal great insight into the early period of solar system history and perhaps into the actual formation processes themselves. However, little knowledge has been gained of this very early stage for several reasons: The intense surface bombardment of all larger bodies, particularly in the inner solar system during that period; the subsequent differentiation of large bodies; and atmospheric effects and continued bombardment of the surface. The most promising approach to acquisition of knowledge pertaining to the early state of the solar system, its origin and evolution, therefore seems to be in the study of small bodies, e. g., comets and asteroids.

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