The Rise and Fall of the Oslo School

In 1931 Ragnar Frisch became professor at the University of Oslo. By way of his research, a new study programme and new staff he created the ”Oslo School”, characterised by mathematical modelling, econometrics, economic planning and scepticism towards the market economy. Consequently, detailed state economic planning and governance dominated Norwegian economic policy for three decades after WWII. In the 1970s the School’s dominance came to an end when the belief in competitive markets gained a foothold and the economy had poor performance. As a result a decentralized market economy was reintroduced. However, mathematical modelling and econometrics remain in the core of most economic programmes.

Representations of world coordinates in FITS

The initial descriptions of the FITS format provided a simplified method for describing the physical coordinate values of the image pixels, but deliberately did not specify any of the detailed conventions required to convey the complexities of actual image coordinates. Building on conventions in wide use within astronomy, this paper proposes general extensions to the original methods for describing the world coordinates of FITS data. In subsequent papers, we apply these general conventions to the methods by which spherical coordinates may be projected onto a two-dimensional plane and to frequency/wavelength/velocity coordinates.Comment: 15 Pages, 1 figure, LaTex with Astronomy & Astrophysics macro package, submitted to A&A, related papers at http://www.aoc.nrao.edu/~egreise

Representations of celestial coordinates in FITS

In Paper I, Greisen & Calabretta (2002) describe a generalized method for assigning physical coordinates to FITS image pixels. This paper implements this method for all spherical map projections likely to be of interest in astronomy. The new methods encompass existing informal FITS spherical coordinate conventions and translations from them are described. Detailed examples of header interpretation and construction are given.Comment: Consequent to Paper I: "Representations of world coordinates in FITS". 45 pages, 38 figures, 13 tables, aa macros v5.2 (2002/Jun). Both papers submitted to Astronomy & Astrophysics (2002/07/19). Replaced to try to get figure and table placement right (no textual changes

Ferromagnetism in a hard-core boson model

The problem of ferromagnetism -- associated with a ground state with maximal total spin -- is discussed in the framework of a hard-core model, which forbids the occupancy at each site with more than one particle. It is shown that the emergence of ferromagnetism on finite square lattices crucially depends on the statistics of the particles. Fermions (electrons) lead to the well-known instabilities for finite hole densities, whereas for bosons (with spin) ferromagnetism appears to be stable for all hole densities.Comment: 8 pages, 7 figures, RevTex

The breakdown of the Nagaoka phase in the 2D t-J model

In the limit of weak exchange, J, at low hole concentration, the ground state of the 2D t-J model is believed to be ferromagnetic. We study the leading instability of this Nagaoka state, which emerges with increasing J. Both exact diagonalization of small clusters, and a semiclassical analytical calculation of larger systems show that above a certain critical value of the exchange, Nagaoka's state is unstable to phase separation. In a finite-size system a bubble of antiferromagnetic Mott insulator appears in the ground state above this threshold. The size of this bubble depends on the hole concentration and scales as a power of the system size, N

Development of an expert data reduction assistant

We propose the development of an expert system tool for the management and reduction of complex data sets. The proposed work is an extension of a successful prototype system for the calibration of CCD images developed by Dr. Johnston in 1987. The reduction of complex multi-parameter data sets presents severe challenges to a scientist. Not only must a particular data analysis system be mastered, (e.g. IRAF/SDAS/MIDAS), large amounts of data can require many days of tedious work and supervision by the scientist for even the most straightforward reductions. The proposed Expert Data Reduction Assistant will help the scientist overcome these obstacles by developing a reduction plan based on the data at hand and producing a script for the reduction of the data in a target common language

Multilevel modelling of mechanical properties of textile composites: ITOOL Project

The paper presents an overview of the multi-level modelling of textile composites in the ITOOL project, focusing on the models of textile reinforcements, which serve as a basis for micromechanical models of textile composites on the unit cell level. The modelling is performed using finite element analysis (FEA) or approximate methods (method of inclusions), which provide local stiffness and damage information to FEA of composite part on the macro-level

Desempenho da cultura do milho após três anos da aplicação de pó de basalto ao solo, com e sem fertilização.

O objetivo desse trabalho foi avaliar o efeito de doses de pó de basalto sobre a produtividade de milho, três anos após sua aplicação ao solo, em sistema de plantio direto, combinadas com a presença ou ausência de fertilização química. Não houve efeito de doses de pó de basalto e da interação entre as doses e a adubação sobre a produtividade de milho cultivado após três anos da aplicação do pó de basalto, todavia, houve efeito apenas de adubação, sendo essa prática favorável ao rendimento da cultura

Atributos químicos de um Latossolo Vermelho Distrófico típico afetados pela aplicação de pó de basalto.

Resumo – O pó de basalto, como fertilizante de liberação lenta, tem apresentado uma série de benefícios ao solo, especialmente, na sua capacidade de fornecer nutrientes às plantas. O objetivo deste trabalho foi o de avaliar, em casa de vegetação, o efeito da aplicação de pó de basalto em alguns atributos químicos de um Latossolo Vermelho Distrófico típico, após 30, 60, 120 e 360 dias de incubação. Os tratamentos consistiram de doses de pó de basalto, com granulometria muito fina, cuja composição era: MgO = 4,83 %; K2O = 1,17 %; P2O5 = 0,2% e CaO = 9%. Foram utilizadas doses equivalentes a 0, 2, 4, 8 e 12 t ha-1. Utilizou-se delineamento completamente casualizado com quatro repetições. Os dados coletados foram submetidos à análise de variância e à análise de regressão polinomial. O pó de basalto com a granulometria testada apresenta dissolução em um prazo mínimo de 30 dias. Foi verificado que em ambiente sem dreno de nutrientes há diminuição dos teores de Ca e Mg trocáveis e do pH do solo e aumentos dos teores de Al e P, com a aplicação do pó de basalto