Maxwell's investigations into the stability of Saturn's rings provide one of the earliest analyses of the dynamics of astrophysical discs. Current research in planetary rings extends Maxwell's kinetic theory to treat dense granular gases of particles undergoing moderately frequent inelastic collisions. Rather than disrupting the rings, local instabilities may be responsible for generating their irregular radial structure. Accretion discs around black holes or compact stars consist of a plasma permeated by a tangled magnetic field and may be compared with laboratory fluids through an analogy that connects Maxwell's researches in electromagnetism and viscoelasticity. A common theme in this work is the appearance of a complex fluid with a dynamical constitutive equation relating the stress in the medium to the history of its deformation.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1098/rsta.2007.2180 | DOI Listing |
J Chem Phys
January 2025
Fritz Haber Research Center for Molecular Dynamics, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
Complex organic molecules are widespread in different areas of the interstellar medium, including cold areas, such as molecular clouds, where chemical reactions occur in ice. Among the observed molecules are oxygen-bearing organic molecules, which are of high interest given their significant role in astrobiology. Despite the observed rich chemistry, the underlying molecular mechanisms responsible for molecular formation in such cold dilute areas are still not fully understood.
View Article and Find Full Text PDFCommun Chem
January 2025
Energy & Materials Transition, Netherlands Organization for Applied Scientific Research (TNO), Urmonderbaan 22, Geleen, 6167RD, The Netherlands.
Time-resolved coherent Raman spectroscopy (CRS) is a powerful non-linear optical technique for quantitative, in-situ analysis of chemically reacting flows, offering unparalleled accuracy and exceptional spatiotemporal resolution. Its application to large polyatomic molecules, crucial for understanding reaction dynamics, has thus far been limited by the complexity of their rotational-vibrational Raman spectra. Progress in developing comprehensive spectral codes for these molecules, a longstanding goal, has been hindered by prohibitively long computation times required for their spectral synthesis.
View Article and Find Full Text PDFACS Infect Dis
January 2025
Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
Alphaviruses, a genus of vector-borne viruses in the family, encode a small ion-channel-forming protein, 6K, and its transframe variant (TF) during infections. Although 6K/TF have vital roles in glycoprotein transport, virus assembly, and budding, there is no mechanistic explanation for these functions. We investigated the distinct biochemical functionalities of 6K and TF from the mosquito-borne alphavirus, Chikungunya Virus.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Univ Paris Est Creteil and Université Paris Cité, CNRS, LISA, F-94010 Créteil, France.
Large amplitude motions (LAMs), most notably represented by proton tunneling, mark a significant departure from small amplitude vibrations where protons merely oscillate around their equilibrium positions. These substantial displacements require tunneling through potential energy barriers, leading to splittings in, e.g.
View Article and Find Full Text PDFNature
December 2024
NRC Herzberg, Victoria British Columbia, Canada.
Recent observations have found a large number of supermassive black holes already in place in the first few hundred million years after the Big Bang, many of which seem to be overmassive relative to their host galaxy stellar mass when compared with local relation. Several different models have been proposed to explain these findings, ranging from heavy seeds to light seeds experiencing bursts of high accretion rate. Yet, current datasets are unable to differentiate between these various scenarios.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!