A new formula for the conserved charges in 3+1 gravity for spacetimes with local anti-de Sitter asymptotic geometry is proposed. It is shown that requiring the action to have an extremum for this class of asymptotia sets the boundary term that must be added to the Lagrangian as the Euler density with a fixed weight factor. The resulting action gives rise to the mass and angular momentum as Noether charges associated to the asymptotic Killing vectors without requiring specification of a reference background in order to have a convergent expression. A consequence of this definition is that any negative constant curvature spacetime has vanishing Noether charges. These results remain valid in the Lambda = 0 limit.
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http://dx.doi.org/10.1103/PhysRevLett.84.1647 | DOI Listing |
Nat Commun
January 2025
Department of Biology, University of Konstanz, Konstanz, Germany.
Phosphorylation of substrates by cyclin-dependent kinases (CDKs) is the driving force of cell cycle progression. Several CDK-activating cyclins are involved, yet how they contribute to substrate specificity is still poorly understood. Here, we discover that a positively charged pocket in cyclin B1, which is exclusively conserved within B-type cyclins and binds phosphorylated serine- or threonine-residues, is essential for correct execution of mitosis.
View Article and Find Full Text PDFNeurochem Res
January 2025
Drosophila and Nanoscience Research Laboratory, Department of Applied Genetics, Karnatak University, Dharwad, Karnataka, 580003, India.
This review explores the intricate connections between Drosophila models and the human blood-brain barrier (BBB) with nanoparticle-based approaches for neurological treatment. Drosophila serves as a powerful model organism due to its evolutionary conservation of key biological processes, particularly in the context of the BBB, which is formed by glial cells that share structural and functional similarities with mammalian endothelial cells. Recent advancements in nanoparticle technology have highlighted their potential for effective drug delivery across the BBB, utilizing mechanisms such as passive diffusion, receptor-mediated transcytosis, and carrier-mediated transport.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Mathematics, Khalifa University of Science and Technology, PO Box 127788, Abu Dhabi, UAE.
We propose a general approach to quasi-deform the Korteweg-De Vries (KdV) equation by deforming its Hamiltonian. The standard abelianization process based on the inherent sl(2) loop algebra leads to an infinite number of anomalous conservation laws, that yield conserved charges for definite space-time parity of the solution. Judicious choice of the deformed Hamiltonian yields an integrable system with scaled parameters as well as a hierarchy of deformed systems, some of which possibly are quasi-integrable.
View Article and Find Full Text PDFJ Environ Manage
January 2025
Conservation Economics Institute, USA and Oregon State University, USA.
The U.S. Department of Interior's Bureau of Land Management regulates oil and gas development on 23 million acres of U.
View Article and Find Full Text PDFEnviron Sci Process Impacts
January 2025
Eberhard Karls University of Tübingen, Department of Geosciences, Schnarrenbergstraße 94-96, 72076 Tübingen, Germany.
Concentrations of pollutants like pharmaceuticals in soils typically decrease over time, though it often remains unclear whether this dissipation is caused by the transformation of the pollutant or a decreasing extractability. We developed a mathematical model that (1) explores the plausibility of different dissipation pathways, and (2) allows the quantification of concentration differences between aqueous soil extracts and soil solution. The model considers soil particles as uniform spheres, kinetic sorption towards an equilibrium (Freundlich model), and two dissipation pathways, irreversible transformation and mineralization (following 1 order kinetics) as well as the formation of non-extractable residues intraparticle diffusion.
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