Effective Hamiltonians for atoms in very strong magnetic fields

We propose three effective Hamiltonians which approximate atoms in very strong homogeneous magnetic fields $B$ modelled by the Pauli Hamiltonian, with fixed total angular momentum with respect to magnetic field axis. All three Hamiltonians describe $N$ electrons and a fixed nucleus where the Coulomb interaction has been replaced by $B$-dependent one-dimensional effective (vector valued) potentials but without magnetic field. Two of them are solvable in at least the one electron case. We briefly sketch how these Hamiltonians can be used to analyse the bottom of the spectrum of such atoms.Comment: 43 page

Inherently Governmental Functions and Other Work Reserved for Performance by Federal Government Employees: The Obama Administration’s Proposed Policy Letter

[Excerpt] On March 31, 2010, the Office of Federal Procurement Policy (OFPP) in the Office of Management and Budget (OMB) issued a proposed policy letter on inherently governmental functions and other “work reserved for performance by federal government employees.” While not final, the policy letter represents the Obama Administration’s proposed guidance for agencies determining (1) whether particular functions are inherently governmental and (2) when functions closely associated with the performance of inherently governmental functions and critical functions should be performed by government personnel. The proposed policy letter was, in part, issued under the authority of the Duncan Hunter National Defense Authorization Act for FY2009 (NDAA\u2709) and President Obama’s memorandum of March 4, 2009, on government contracting. Section 321 of NDAA\u2709 tasked OMB with (1) reviewing existing definitions of “inherently governmental function” to determine whether such definitions are “sufficiently focused” to ensure that only government personnel perform inherently governmental functions or “other critical functions necessary for the mission of a Federal department or agency;” (2) developing a “single consistent definition” of “inherently governmental function” that would address any deficiencies in the existing definitions, reasonably apply to all agencies, and ensure that agency personnel can identify positions that perform inherently governmental functions; (3) developing criteria for identifying critical functions” that should be performed by government personnel; and (4) developing criteria for identifying positions that government personnel should perform in order to ensure that agencies develop and maintain “sufficient organic expertise and technical capacity” to perform their missions and oversee contractors’ work. President Obama’s March 4, 2009, memorandum similarly charged OMB with clarifying when outsourcing is “appropriate.

Fourier transform and rigidity of certain distributions

Let $E$ be a finite dimensional vector space over a local field, and $F$ be its dual. For a closed subset $X$ of $E$, and $Y$ of $F$, consider the space $D^{-\xi}(E;X,Y)$ of tempered distributions on $E$ whose support are contained in $X$ and support of whose Fourier transform are contained in $Y$. We show that $D^{-\xi}(E;X,Y)$ possesses a certain rigidity property, for $X$, $Y$ which are some finite unions of affine subspaces.Comment: 10 page

Excess mortality during heat waves in Ireland

Ireland is not known for having extreme high temperatures, with values above 30C uncommon. Ireland has significant excess winter mortality compared to summer. The objective of this study is to estimate the impact of nation-wide heat waves on the total, cardiovascular and respiratory relationship, for the period 1981–2003, to determine if there are any periods of excess summer mortality

Effect of couplings weakening and reversing in ferromagnetic Ising systems - Rigorous inequalities

We consider Ising systems where all the many-spin couplings $J_A$ are positive. We show that the absolute value of all the many-spin correlations does not increase when the value of any of the couplings is reduced, taking any value in the interval $[-J_A,J_A]$. Results of this type are motivated by work in systems such as random field Ising models.Comment: ps, 5 pages, no figure

Low dimensional magnetic solids and single crystal elpasolites: Need for improved crystal growing techniques

The need for extensive crystal growing experiments to develop techniques for preparing crystals suitable for magnetic anisotropy measurements and detailed X-ray and neutron diffraction studies is rationalized on the basis of the unique magnetic properties of the materials and their hydrogen bonded structures which have many features in common with metalloenzyme and metalloprotein active sites. Single crystals of the single and mixed lanthanide species are prepared by the Bridgeman technique of gradient solidification of molten samples. The effects of crystal imperfections on the optical properties of these materials are an important part of the projected research. A series of a-amido acid complexes of first row transition metals were prepared which crystallize as infinite linear chains and exhibit low dimensional magnetic ordering (one or two) at temperature below 40 K

Using an Egg to Understand the Three Types of Rocks

Bernstein and Wong (1977) have presented an excellent earth science lesson by using the cross-section of a hard-boiled egg. The yolk, white and shell, respectively; represent a model of the earth\u27s core, mantle and crust

Current status of one- and two-dimensional numerical models: Successes and limitations

The capabilities of one and two-dimensional numerical solar cell modeling programs (SCAP1D and SCAP2D) are described. The occasions when a two-dimensional model is required are discussed. The application of the models to design, analysis, and prediction are presented along with a discussion of problem areas for solar cell modeling

Ion kinetic energy conservation and magnetic field strength constancy in multi-fluid solar wind Alfv\'enic turbulence

We investigate properties of the plasma fluid motion in the large amplitude low frequency fluctuations of highly Alfv\'enic fast solar wind. We show that protons locally conserve total kinetic energy when observed from an effective frame of reference comoving with the fluctuations. For typical properties of the fast wind, this frame can be reasonably identified by alpha particles, which, owing to their drift with respect to protons at about the Alfv\'en speed along the magnetic field, do not partake in the fluid low frequency fluctuations. Using their velocity to transform proton velocity into the frame of Alfv\'enic turbulence, we demonstrate that the resulting plasma motion is characterized by a constant absolute value of the velocity, zero electric fields, and aligned velocity and magnetic field vectors as expected for unidirectional Alfv\'enic fluctuations in equilibrium. We propose that this constraint, via the correlation between velocity and magnetic field in Alfv\'enic turbulence, is at the origin of the observed constancy of the magnetic field: while the constant velocity corresponding to constant energy can be only observed in the frame of the fluctuations, the correspondingly constant total magnetic field, invariant for Galilean transformations, remains the observational signature, in the spacecraft frame, of the constant total energy in the Alfv\'en turbulence frame.Comment: 6 pages, 6 figures, Accepted for publication in The Astrophysical Journa