Evolution: functional evolution of nuclear structure.

The evolution of the nucleus, the defining feature of eukaryotic cells, was long shrouded in speculation and mystery. There is now strong evidence that nuclear pore complexes (NPCs) and nuclear membranes coevolved with the endomembrane system, and that the last eukaryotic common ancestor (LECA) had fully functional NPCs. Recent studies have identified many components of the nuclear envelope in living Opisthokonts, the eukaryotic supergroup that includes fungi and metazoan animals. These components include diverse chromatin-binding membrane proteins, and membrane proteins with adhesive lumenal domains that may have contributed to the evolution of nuclear membrane architecture. Further discoveries about the nucleoskeleton suggest that the evolution of nuclear structure was tightly coupled to genome partitioning during mitosis

Sound clocks and sonic relativity

Sound propagation within certain non-relativistic condensed matter models obeys a relativistic wave equation despite such systems admitting entirely non-relativistic descriptions. A natural question that arises upon consideration of this is, "do devices exist that will experience the relativity in these systems?" We describe a thought experiment in which 'acoustic observers' possess devices called sound clocks that can be connected to form chains. Careful investigation shows that appropriately constructed chains of stationary and moving sound clocks are perceived by observers on the other chain as undergoing the relativistic phenomena of length contraction and time dilation by the Lorentz factor, with c the speed of sound. Sound clocks within moving chains actually tick less frequently than stationary ones and must be separated by a shorter distance than when stationary to satisfy simultaneity conditions. Stationary sound clocks appear to be length contracted and time dilated to moving observers due to their misunderstanding of their own state of motion with respect to the laboratory. Observers restricted to using sound clocks describe a universe kinematically consistent with the theory of special relativity, despite the preferred frame of their universe in the laboratory. Such devices show promise in further probing analogue relativity models, for example in investigating phenomena that require careful consideration of the proper time elapsed for observers.Comment: (v2) consistent with published version; (v1) 15 pages, 9 figure

Correlation of the orbach relaxation coefficient with optical linewidths- laf3-er3 plus

Correlation of Orbach coefficient of spin-lattice relaxation with optical transition linewidths for trivalent erbium in lanthanum fluorid

Quantum signatures of breather-breather interactions

The spectrum of the Quantum Discrete Nonlinear Schr\"odinger equation on a periodic 1D lattice shows some interesting detailed band structure which may be interpreted as the quantum signature of a two-breather interaction in the classical case. We show that this fine structure can be interpreted using degenerate perturbation theory.Comment: 4 pages, 4 fig

The Economic Reunification of Korea: A Dynamic General Equilibrium Model

This paper constructs a dynamic specific factors model to examine the impact of the economic reunification of North and South Korea. The model is a compromise between the highly stylized neoclassical models of trade found in the theoretical trade literature, and the highly aggregated models used in dynamic macroeconomics. We find that the policies with the biggest effects on aggregate output are changes in government tax and spending rates, particularly spending on infrastructure. In contrast, we find that both skilled and unskilled wages are much more responsive to the particulars of trade policy, particularly openness to intra-Korea trade and intra-Korea labor mobility. The location of production in a fully integrated Korean economy is determined by the location of infrastructure.factor mobility; dynamic general equilibrium; specific-factors; Korea