Results 131 to 140 of about 197,812 (267)

Resolution of the cosmological constant problem by unimodular gravity and signature reversal symmetry

Physics Letters B
The (old) cosmological constant problem consists of two different problems. The first is the huge discrepancy between the value of the cosmological constant deduced from observations and its value expected from cosmological constant-like theoretical ...
Recai Erdem
doaj   +1 more source

Confirmation of the impact origin of the Late Ordovician Tvären impact structure (southeast Sweden) and emplacement of impactites in a marine setting

Meteoritics &Planetary Science, EarlyView.
Abstract The Tvären structure in southeastern Sweden has been listed as a confirmed marine‐target impact structure for decades. However, to date, no measurements and/or indexed data of planar deformation features in quartz grains from the structure have been published or any other unequivocal evidence of impact.
Katarzyna J. Gajewska, Sanna Alwmark, Mikael Calner, Sylvain Richoz, Jens Ormö, Erik Sturkell, Carl Alwmark   +6 more
wiley   +1 more source

Polymict melt‐bearing breccia dikes in the Morokweng impact structure formed by slip‐induced mechanical mixing of pseudotachylite and cataclasite along large‐displacement impact faults

Meteoritics &Planetary Science, EarlyView.
Abstract A core drilled through shocked and faulted Archean granitoid gneisses and dolerites in the eroded peak ring of the 70–80 km diameter Morokweng impact structure intersects multiple centimeter‐ to meter‐wide clastic‐matrix breccias containing a polymict clast population of lithic and mineral clasts and altered, millimeter‐ to centimeter ‐size ...
Roger L. Gibson, S'lindile S. Wela, Leonidas C. Vonopartis, Marco A. G. Andreoli   +3 more
wiley   +1 more source

In situ single‐spot Rb/Sr cosmochronology of roedderite in the Ribbeck aubrite (asteroid 2024 BX1)

Meteoritics &Planetary Science, EarlyView.
Abstract The mineralogy and textures of several fragments from the Ribbeck aubrite were analyzed using a combination of scanning electron microscopy, electron microprobe analysis, μRaman spectroscopy, and laser ablation inductively coupled reaction cell mass spectrometry (LA‐ICP‐MS/MS).
Christopher J. Barnes, Aleksander Błasiak, Helge Vinje Birgerheim, Matthias Konrad‐Schmolke, Delia Rösel, Jarosław Majka, Thomas Zack   +6 more
wiley   +1 more source

Rational Ruijsenaars-Schneider model with cosmological constant

Journal of High Energy Physics
The Ruijsenaars-Schneider models are integrable dynamical realizations of the Poincaré group in 1 + 1 dimensions, which reduce to the Calogero and Sutherland systems in the nonrelativistic limit.
Anton Galajinsky
doaj   +1 more source

Charged wormholes in (anti-)de Sitter spacetime

Physics Letters B
We present a family of charged, traversable wormhole solutions in the presence of a cosmological constant. In de Sitter spacetime, two types of wormhole throats can exist–referred to as typical and cosmological throat–located at small and large radial ...
Hyeong-Chan Kim, Wonwoo Lee
doaj   +1 more source

Mountain‐top spherules: Criteria to identify natural and synthetic particles

Meteoritics &Planetary Science, EarlyView.
Abstract Natural microspherules are important tracers of geologic and environmental processes in modern and ancient deposits. However, anthropogenic contamination can dilute natural collections by releasing synthetic microspherules into the environment.
M. R. Boyd, M. J. Genge
wiley   +1 more source

The effect of terrestrial weathering on the mineralogy and petrologic (sub)types of CM chondrites explored by kinetic modeling and laboratory experiments

Meteoritics &Planetary Science, EarlyView.
Abstract Terrestrial weathering alters the chemical and isotopic composition, and mineralogy, of meteorites; its effects on ordinary chondrites are well‐studied, but relatively little is known about the susceptibility of carbonaceous chondrites. We combined laboratory experiments, whereby Chwichiya 002 (C3‐ung find), Murchison (CM2 fall) and Kolang ...
Robin L. Haller, Martin R. Lee, Mark E. Hodson   +2 more
wiley   +1 more source

“We Have Come to Offer Something Which (They) Were Not Even Looking for”: U.S. Christian Conservative Evangelical Faith Missions in the Ecuadorian Upper Amazon

The Journal of American Culture, EarlyView.
Diego Mauricio Cortés
wiley   +1 more source

An unsupervised machine learning approach to iron meteorite classification

Meteoritics &Planetary Science, EarlyView.
Abstract Iron meteorites are usually classified manually using bivariate elemental plots. This study extends iron meteorite classification into multi‐element space. We present a computational method for the classification of iron meteorites by applying unsupervised machine learning using density‐based cluster analysis.
Louis‐Alexandre Lobanov, Hilary Downes
wiley   +1 more source