Results 111 to 120 of about 151,775 (355)

Recycling Argon through Metamorphic Reactions: the Record in Symplectites [PDF]

open access: yes, 2018
The 40Ar/39Ar ages of metamorphic micas that crystallized at high temperatures are commonly interpreted as cooling ages, with grains considered to have lost 40Ar via thermally-driven diffusion into the grain boundary network.
Allaz   +82 more
core   +2 more sources

Time after time – circadian clocks through the lens of oscillator theory

open access: yesFEBS Letters, EarlyView.
Oscillator theory bridges physics and circadian biology. Damped oscillators require external drivers, while limit cycles emerge from delayed feedback and nonlinearities. Coupling enables tissue‐level coherence, and entrainment aligns internal clocks with environmental cues.
Marta del Olmo   +2 more
wiley   +1 more source

Impacts of Common Lead on Apatite U-Pb Geochronology by LA-ICP-MS: Assessment and Correction Strategies

open access: yesYankuang ceshi
Apatite is a widespread U-bearing mineral in igneous, metamorphic, and sedimentary rocks. U-Pb geochronology of apatite can provide significant information for constraining magmatic evolution processes and tracing provenance.
Tao LUO   +4 more
doaj   +1 more source

Is there a Grenvillian basement in the Guerrero-Morelos Platform of Mexico?

open access: yesGeologica Acta, 2007
In the Guerrero-Morelos platform (Guerrero State, Mexico) the adakitic rocks of Early Tertiary age contain abundant hornblende-rich tonalite xenoliths. Zircon crystals have been concentrated from both adakites and xenoliths, and dated using in-situ U-Pb ...
G. Levresse   +3 more
doaj   +1 more source

Earthtime Lesson Plan for U/Pb Dating (grade 8-12) [PDF]

open access: yes
The Earthtime Lesson Plan is a complete description of a radiometric dating module taught to high school students at MIT. U/Pd dating and it's uses, teacher background, materials needed, time frame and National Science Standards are all provided as well ...

core  

Review on the different method of dating mafic-ultramafic rocks in the orogenic belt - taking the Shunchang massif as an example [PDF]

open access: yes, 1996
Based on the analysis of different dating methods of isotopic system and the dating results of the metamorphic mafic-ultramafic rocks in Shunchang, Northern Fujian, it s proposed in the paper that the U-Pb method of single zircon and the method of the ...
Li, J, Ren, S, Sun, M, Zhou, X
core  

Nature and timing of Late Mississippian to Mid-Pennsylvanian glacio-eustatic sea-level changes of the Pennine Basin, UK [PDF]

open access: yes, 2012
The Pennine Basin of northern England contains a comparatively complete Serpukhovian– Moscovian succession characterized by high-resolution ammonoid zonation and cyclic paralic sedimentation.
Condon, Daniel J., Waters, Colin N.
core   +2 more sources

Conserved structural motifs in PAS, LOV, and CRY proteins regulate circadian rhythms and are therapeutic targets

open access: yesFEBS Letters, EarlyView.
Cryptochrome and PAS/LOV proteins play intricate roles in circadian clocks where they act as both sensors and mediators of protein–protein interactions. Their ubiquitous presence in signaling networks has positioned them as targets for small‐molecule therapeutics. This review provides a structural introduction to these protein families.
Eric D. Brinckman   +2 more
wiley   +1 more source

In situ molecular organization and heterogeneity of the Legionella Dot/Icm T4SS

open access: yesFEBS Letters, EarlyView.
We present a nearly complete in situ model of the Legionella Dot/Icm type IV secretion system, revealing its central secretion channel and identifying new components. Using cryo‐electron tomography with AI‐based modeling, our work highlights the structure, variability, and mechanism of this complex nanomachine, advancing understanding of bacterial ...
Przemysław Dutka   +11 more
wiley   +1 more source

New insights from U–Pb zircon dating of Early Ordovician magmatism on [PDF]

open access: yes, 2008
The Central Iberian–Ossa-Morena transition zone (SW Iberian Massif) represents a segment of the northern Gondwana margin with a long geodynamic evolution, characterized by the superposition of Cadomian and Variscan events.
Bea, Fernando   +7 more
core  

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