Rossby waves and α\alpha-effect

Rossby waves drifting in the azimuthal direction are a common feature at the onset of thermal convective instability in a rapidly rotating spherical shell. They can also result from the destabilization of a Stewartson shear layer produced by differential rotation as expected in the liquid sodium experiment (DTS) working in Grenoble, France. A usual way to explain why Rossby waves can participate to the dynamo process goes back to Busse (1975). In his picture, the flow geometry is a cylindrical array of parallel rolls aligned with the rotation axis. The axial flow component (the component parallel to the rotation axis) is (i) maximum in the middle of each roll and changes its sign from one roll to the next. It is produced by the Ekman pumping at the fluid containing shell boundary. The corresponding dynamo mechanism can be explained in terms of an $\alpha$-tensor with non-zero coefficients on the diagonal. In rapidly rotating objects like the Earth's core (or in a fast rotating experiment), Rossby waves occur in the limit of small Ekman number ($\approx 10^{-15}$). In that case, the main source of the axial flow component is not the Ekman pumping but rather the ``geometrical slope effect'' due to the spherical shape of the fluid containing shell. This implies that the axial flow component is (ii) maximum at the borders of the rolls and not at the centers. If assumed to be stationary, such rolls would lead to zero coefficients on the diagonal of the $\alpha$-tensor, making the dynamo probably less efficient if possible at all. Actually, the rolls are drifting as a wave, and we show that this drift implies non--zero coefficients on the diagonal of the $\alpha$-tensor. These new coefficients are in essence very different from the ones obtained in case (i) and cannot be interpreted in terms of the heuristic picture of Busse (1975)

Comprehensive Monosynaptic Rabies Virus Mapping of Host Connectivity with Neural Progenitor Grafts after Spinal Cord Injury.

Neural progenitor cells grafted to sites of spinal cord injury have supported electrophysiological and functional recovery in several studies. Mechanisms associated with graft-related improvements in outcome appear dependent on functional synaptic integration of graft and host systems, although the extent and diversity of synaptic integration of grafts with hosts are unknown. Using transgenic mouse spinal neural progenitor cell grafts expressing the TVA and G-protein components of the modified rabies virus system, we initiated monosynaptic tracing strictly from graft neurons placed in sites of cervical spinal cord injury. We find that graft neurons receive synaptic inputs from virtually every known host system that normally innervates the spinal cord, including numerous cortical, brainstem, spinal cord, and dorsal root ganglia inputs. Thus, implanted neural progenitor cells receive an extensive range of host neural inputs to the injury site, potentially enabling functional restoration across multiple systems

King v. Burwell and the Triumph of Selective Contextualism

King v. Burwell presented the question of whether the Patient Protection and Affordable Care Act of 2010 (ACA) authorizes the Internal Revenue Service (IRS) to issue tax credits for the purchase of health insurance through Exchanges established by the federal government. The King plaintiffs alleged an IRS rule purporting to authorize tax credits in federal Exchanges was unlawful because the text of the ACA expressly authorizes tax credits only in Exchanges “established by the State.” The Supreme Court conceded the plain meaning of the operative text, and that Congress defined “State” to exclude the federal government. The Court nevertheless disagreed with the plaintiffs, explaining that “the context and structure of the Act compel us to depart from what would otherwise be the most natural reading of the pertinent statutory phrase.” The Court reached its conclusion by disregarding portions of the ACA’s text and considering only selected elements of the ACA’s structure, context, and purpose. The King majority’s selective contextualism embraced an unexpressed congressional “plan” at the expense of the plan Congress actually enacted

Taxation Without Representation: The Illegal IRS Rule to Expand Tax Credits Under the PPACA

The Patient Protection and Affordable Care Act (PPACA) provides tax credits and subsidies for the purchase of qualifying health insurance plans on state-run insurance exchanges. Contrary to expectations, many states are refusing or otherwise failing to create such exchanges. An Internal Revenue Service (IRS) rule purports to extend these tax credits and subsidies to the purchase of health insurance in federal exchanges created in states without exchanges of their own. This rule lacks statutory authority. The text, structure, and history of the Act show that tax credits and subsidies are not available in federally run exchanges. The IRS rule is contrary to congressional intent and cannot be justified on other legal grounds. Because the granting of tax credits can trigger the imposition of fines on millions of individuals and employers, the IRS rule is likely to be challenged in court

King v. Burwell and the Triumph of Selective Contextualism

King v. Burwell presented the question of whether the Patient Protection and Affordable Care Act of 2010 (ACA) authorizes the Internal Revenue Service (IRS) to issue tax credits for the purchase of health insurance through Exchanges established by the federal government. The King plaintiffs alleged an IRS rule purporting to authorize tax credits in federal Exchanges was unlawful because the text of the ACA expressly authorizes tax credits only in Exchanges “established by the State.” The Supreme Court conceded the plain meaning of the operative text, and that Congress defined “State” to exclude the federal government. The Court nevertheless disagreed with the plaintiffs, explaining that “the context and structure of the Act compel us to depart from what would otherwise be the most natural reading of the pertinent statutory phrase.” The Court reached its conclusion by disregarding portions of the ACA’s text and considering only selected elements of the ACA’s structure, context, and purpose. The King majority’s selective contextualism embraced an unexpressed congressional “plan” at the expense of the plan Congress actually enacted

Quantum-Liouville and Langevin Equations for Gravitational Radiation Damping

From a forward--backward path integral, we derive a master equation for the emission and absorption of gravitons by a massive quantum object in a heat bath of gravitons. Such an equation could describe collapse phenomena of dense stars. We also present a useful approximate Langevin equation for such a system.Comment: Author Information under http://www.physik.fu-berlin.de/~kleinert/institution.html . Latest update of paper (including all PS fonts) at http://www.physik.fu-berlin.de/~kleinert/31

Interhemispheric comparison of atmospheric circulation features as evaluated from Nimbus satellite data

A relationship is established between relative geostrophic vorticity on an isobaric surface and the Laplacian of the underlying layer-mean temperature. This relationship is used to investigate the distribution of vorticity and baroclinicity in a jet-stream model which is constantly recurrent in the winter troposphere. The investigation shows that the baroclinic and vorticity fields of the extratropical troposphere must be bifurcated with two extrema in the middle and subpolar latitudes. This pattern is present in daily tropospheric meridional cross-sections. The reasons for the disappearance of bifurcation in the time-and-longitude averaged distributions are discussed

On Di\'osi-Penrose criterion of gravity-induced quantum collapse

It is shown that the Di\'osi-Penrose criterion of gravity-induced quantum collapse may be inconsistent with the discreteness of space-time, which is generally considered as an indispensable element in a complete theory of quantum gravity. Moreover, the analysis also suggests that the discreteness of space-time may result in rapider collapse of the superposition of energy eigenstates than required by the Di\'osi-Penrose criterion.Comment: 5 pages, no figure

Mechanisms of arsenic clustering in silicon

A model of arsenic clustering in silicon is proposed and analyzed. The main feature of the proposed model is the assumption that negatively charged arsenic complexes play a dominant role in the clustering process. To confirm this assumption, electron density and concentration of impurity atoms incorporated into the clusters are calculated as functions of the total arsenic concentration. A number of the negatively charged clusters incorporating a point defect and one or more arsenic atoms are investigated. It is shown that for the doubly negatively charged clusters or for clusters incorporating more than one arsenic atom the electron density reaches a maximum value and then monotonically and slowly decreases as total arsenic concentration increases. In the case of doubly negatively charged cluster incorporating two arsenic atoms, the calculated electron density agrees well with the experimental data. Agreement with the experiment confirms the conclusion that two arsenic atoms participate in the cluster formation. Among all present models, the proposed model of clustering by formation of doubly negatively charged cluster incorporating two arsenic atoms gives the best fit to the experimental data and can be used in simulation of high concentration arsenic diffusion.Comment: 13 pages, 4 figures. Revised and shortened version of the paper has been published in Phys. Rev. B, Vol.74 (3), art. no. 035205 (2006

On the Electromagnetic Properties of Matter in Collapse Models

We discuss the electromagnetic properties of both a charged free particle, and a charged particle bounded by an harmonic potential, within collapse models. By choosing a particularly simple, yet physically relevant, collapse model, and under only the dipole approximation, we are able to solve the equation of motion exactly. In this way, both the finite time and large time behavior can be analyzed accurately. We discovered new features, which did not appear in previous works on the same subject. Since, so far, the spontaneous photon emission process places the strongest upper bounds on the collapse parameters, our results call for a further analysis of this process for those atomic systems which can be employed in experimental tests of collapse models, as well as of quantum mechanics.Comment: 17 pages, LaTeX, updated version with minor change