The Notostigmata, a new suborder of Acari

The following studies on this new suborder have been made on material included in the famous French Arachnologist E. Simon's rich collection and lent by him to Drs. H. J. Hansen and W. Sørensen. ..

Molecular charge distribution of CO

The difference electron density of CO is studied by comparison of several calculations. It is shown that the Hartree-Fock-Slater and Hartree-Fock methods yield equally good charge-distributions and that the use of minimal basis sets should be avoided

Learning Mathematics without Limits and All-attainment Grouping in Secondary Schools: Pete's story

This article is about Pete’s story. It is a story about introducing all attainment teaching in a secondary school mathematics department and about espousing and enacting a pedagogy and set of practices to enable learning mathematics without limits

Mean Field Limit for Coulomb-Type Flows

We establish the mean-field convergence for systems of points evolving along the gradient flow of their interaction energy when the interaction is the Coulomb potential or a super-coulombic Riesz potential, for the first time in arbitrary dimension. The proof is based on a modulated energy method using a Coulomb or Riesz distance, assumes that the solutions of the limiting equation are regular enough and exploits a weak-strong stability property for them. The method can handle the addition of a regular interaction kernel, and applies also to conservative and mixed flows. In the appendix, it is also adapted to prove the mean-field convergence of the solutions to Newton's law with Coulomb or Riesz interaction in the monokinetic case to solutions of an Euler-Poisson type system.Comment: Final version with expanded introduction, to appear in Duke Math Journal. 35 page

Who are New England's immigrants?

Foreign immigration is driving New England's population growth and shaping the region's economic and demographic character. Who are the region's immigrants? Where do they live? How are they doing? An analysis by the Federal Reserve Bank of Boston answers some of these questions.Immigrants - New England

Crystal structure and charge distribution of pyrazine: effects of extinction, thermal diffuse scattering and series termination

The crystal structure and electronic charge distribution of pyrazine (1,4-diazabenzene) has been determined at 184 K by X-ray methods. The structural results of Wheatley [Acta Cryst. (1957), 10, 182-187] have been confirmed. A clear indication of bonding effects is obtained. Neither positional and thermal parameters nor difference-Fourier maps are affected by extinction. The effect of thermal diffuse scattering (TDS) on positional parameters is also negligible. However, after correction for TDS, thermal parameters increase significantly. The difference-Fourier map is influenced by TDS as well as the inclusion of high-order Fourier terms