1,369 research outputs found
Cluster algebras in algebraic Lie theory
We survey some recent constructions of cluster algebra structures on
coordinate rings of unipotent subgroups and unipotent cells of Kac-Moody
groups. We also review a quantized version of these results.Comment: Invited survey; to appear in Transformation Group
On acceleration and motion of ions in corona and solar wind
Equations of motion for ions in corona and solar win
Crew engineering test plan for evaluation of the Array E Antenna Aiming Mechanism
To determine if a pressure-suited deployment of the Array E (Apollo 17) Antenna Aiming Mechanism would present any handling and/or adjustment problems to the crew.prepared by H. W. Geiss
Fractional smoothness and applications in finance
This overview article concerns the notion of fractional smoothness of random
variables of the form , where is a certain
diffusion process. We review the connection to the real interpolation theory,
give examples and applications of this concept. The applications in stochastic
finance mainly concern the analysis of discrete time hedging errors. We close
the review by indicating some further developments.Comment: Chapter of AMAMEF book. 20 pages
Actin assembly ruptures the nuclear envelope by prying the lamina away from nuclear pores and nuclear membranes in starfish oocytes.
The nucleus of oocytes (germinal vesicle) is unusually large and its nuclear envelope (NE) is densely packed with nuclear pore complexes (NPCs) stockpiled for embryonic development. We showed that breakdown of this specialized NE is mediated by an Arp2/3-nucleated F-actin 'shell' in starfish oocytes, in contrast to microtubule-driven tearing in mammalian fibroblasts. Here, we address the mechanism of F-actin-driven NE rupture by correlated live-cell, super-resolution and electron microscopy. We show that actin is nucleated within the lamina sprouting filopodia-like spikes towards the nuclear membranes. These F-actin spikes protrude pore-free nuclear membranes, whereas the adjoining membrane stretches accumulate NPCs associated with the still-intact lamina. Packed NPCs sort into a distinct membrane network, while breaks appear in ER-like, pore-free regions. Thereby, we reveal a new function for actin-mediated membrane shaping in nuclear rupture that is likely to have implications in other contexts such as nuclear rupture observed in cancer cells
Big Bang Nucleosynthesis Constraints on the Self-Gravity of Pressure
Using big bang nucleosynthesis and present, high-precision measurements of
light element abundances, we constrain the self-gravity of radiation pressure
in the early universe. The self-gravity of pressure is strictly non-Newtonian,
and thus the constraints we set provide a direct test of this prediction of
general relativity and of the standard, Robertson-Walker-Friedmann cosmology.Comment: 5 pages, 1 figure. This paper was developed from an earlier version
which was posted as arXiv:0707.358
Big Bang Nucleosynthesis with Long Lived Charged Massive Particles
We consider Big Bang Nucleosynthesis (BBN) with long lived charged massive
particles. Before decaying, the long lived charged particle recombines with a
light element to form a bound state like a hydrogen atom. This effect modifies
the nuclear reaction rates during the BBN epoch through the modifications of
the Coulomb field and the kinematics of the captured light elements, which can
change the light element abundances. It is possible that the heavier nuclei
abundances such as Li and Be decrease sizably, while the ratios ,
D/H, and He/H remain unchanged. This may solve the current discrepancy
between the BBN prediction and the observed abundance of Li. If future
collider experiments found signals of a long-lived charged particle inside the
detector, the information of its lifetime and decay properties could provide
insights to understand not only the particle physics models but also the
phenomena in the early universe in turn.Comment: 20 pages, 6 figures, published version in Physical Review
Implications of the observed anticorrelation between solar wind speed and coronal electron temperature
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95059/1/jgra16514.pd
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