Noncommutative Geometry: Calculation of the Standard Model Lagrangian

The calculation of the standard model Lagrangian of classical field theory within the framework of noncommutative geometry is sketched using a variant with 18 parameters. Improvements compared with the traditional formulation are contrasted with remaining deviations from the requirements of physics.Comment: 10 pages; contribution to the proceedings of the Euroconference "Brane New World and Noncommutative Geometry", Villa Gualino, Turin, Italy, October 2-7, 200

Analysing Russian food expenditure using micro-data

Since the beginning of transition, the level and structure of average food consumption and expenditure of Russian households has changed substantially. This development has gone together with a steep increase in the share of food in total expenditure. Notable differences with respect to food expenditure are observed between distinct household strata. In this paper, food demand of Russian households is investigated. For this purpose, households are classified by sociodemographic characteristics, and differences between food demand patterns of various household types are described using data of a Russian household survey of 1996. Russian food demand is econometrically estimated for seventeen food commodities belonging to five groups using a two-stage linear approximation of the Almost Ideal Demand System (LA/AIDS). Total expenditure allocation on food and non-food is analysed using Working's Engel model. The basic models are extended by sociodemographic factors. In a first step, unit values of food commodities are adjusted for quality differences and Probit analyses are carried out to analyse the decision to purchase food commodities. In a second step, the Engel model and the LA/AIDS are estimated applying the Generalised Heckman procedure in order to account for estimation bias introduced from zero expenditures. The estimates are used to calculate total expenditure and own price elasticities for different household groups. The results indicate that sociodemographic characteristics exert an important influence on the level and composition of food expenditure and on food demand elasticities. Therefore, if demand analysis shall contribute to the design of comprehensive food and social policies, not only average estimates for the population as a whole, but estimates for specific population groups should be considered. -- G E R M A N V E R S I O N: Seit Beginn der Transformation haben sich das Niveau und die Struktur des durchschnittlichen Nahrungsmittelverbrauchs und der Ausgaben für Nahrungsmittel russischer Haushalte stark verändert. Gleichzeitig ist der Anteil des Nahrungsmittel- am Gesamtbudget der Haushalte deutlich angestiegen. Es sind wesentliche Unterschiede in den Ausgaben für Nahrungsmittel unterschiedlicher Haushaltsgruppen festzustellen. In diesem Papier wird die die Nahrungsmittelnachfrage russischer Haushalte untersucht. Diese werden nach soziodemographischen Charakteristika gruppiert und bestehende Unterschiede in Niveau und Struktur ihrer Nahrungsmittelausgaben heraus gearbeitet. Die Evidenz basiert auf Haushaltsbudgetdaten des Jahres 1996. Die Nahrungsmittelnachfrage wird mittels eines zweistufigen linearisierten Almost Ideal Demand Systems für siebzehn Nahrungsmittel ökonometrisch geschätzt. Die Analyse der Allokation der Gesamtausgaben auf Nahrungsmittel und Nicht-Nahrungsmittel geschieht unter Verwendung eines Engel Modells. Die Modelle werden um soziodemographische Faktoren erweitert. In einem ersten Schritt erfolgt eine Anpassung der als Preisproxy verwendeten Einheitswerte der Nahrungsmittel im Hinblick auf Qualitätsunterschiede zwischen den Aggregaten, und die Kaufentscheidung wird mit Probit Modellen untersucht. In einem zweiten Schritt werden die Engel und die AIDS Gleichungen unter Anwendung der Generalised Heckman Procedure geschätzt. Aus den geschätzten Parametern werden Ausgaben- und Preiselastizitäten für unterschiedliche Haushaltsgruppen berechnet. Die Ergebnisse zeigen, daß soziodemographische Faktoren das Niveau und die Struktur der Nahrungsmittelausgaben sowie der Nachfrageelastizitäten beeinflussen. Für die Gestaltung von Ernährungs- und Sozialpolitiken wäre es mithin wünschenswert, nicht nur durchschnittliche Schätzergebnisse zugrunde zu legen, sondern auch haushaltsspezifische Charakteristika zu berücksichtigen.

Emigration and Wages: The EU Enlargement Experiment

The enlargement of the European Union provides a unique opportunity to study the impact of the lifting of migration restrictions on the migrant sending countries. With EU enlargement in 2004, 1.2 million workers from Eastern Europe emigrated to the UK and Ireland. I use this emigration wave to show that emigration significantly changed the wage distribution in the sending country, in particular between young and old workers. Using a novel dataset from Lithuania, the UK and Ireland for the calibration of a structural model of labor demand, I find that over the period of five years emigration increased the wages of young workers by 6%, while it had no effect on the wages of old workers. Contrary to the immigration literature, there is no significant effect of emigration on the wage distribution between high-skilled and low-skilled workers.emigration, EU enlargement, European integration, wage distribution

On the state of low luminous accreting neutron stars

Observational appearance of a neutron star in the subsonic propeller state which is a companion of a wind-fed mass-exchange close binary system is discussed. During the subsonic propeller state the neutron star magnetosphere is surrounded by a spherical quasi-static plasma envelope, which is extended from the magnetospheric boundary up to the star accretion radius. The energy input to the envelope due to the propeller action by the neutron star exceeds the radiative losses and the plasma temperature in the envelope is of the order of the free-fall temperature. Under this condition the magnetospheric boundary is interchange stable. Nevertheless, I find that the rate of plasma penetration from the envelope into the magnetic field of the neutron star due to diffusion and magnetic field line reconnection processes is large enough for the accretion power to dominate the spindown power. I show that the accretion luminosity of the neutron star in the subsonic propeller state is 5*10**{30} - 10**{33} (dM/dt)_{15} erg/s, where dM/dt is the strength of the normal companion stellar wind which is parametrized in terms of the maximum possible mass accretion rate onto the neutron star magnetosphere. On this basis I suggest that neutron stars in the subsonic propeller state are expected to be observed as low luminous accretion-powered pulsars. The magnetospheric radius of the neutron star in this state is determined by the strength of the stellar wind, (dM/dt)_c, while the accretion luminosity is determined by the rate of plasma penetration into the star magnetosphere, (dM/dt)_a, which is (dM/dt)_a << (dM/dt)_c. That is why the classification of the neutron star state in these objects using the steady accretion model (i.e. setting (dM/dt)_a = (dM/dt)_c) can lead to a mistaken conclusion.Comment: 6 pages, accepted for publication in A&

Efficient Wiener filtering without preconditioning

We present a new approach to calculate the Wiener filter solution of general data sets. It is trivial to implement, flexible, numerically absolutely stable, and guaranteed to converge. Most importantly, it does not require an ingenious choice of preconditioner to work well. The method is capable of taking into account inhomogeneous noise distributions and arbitrary mask geometries. It iteratively builds up the signal reconstruction by means of a messenger field, introduced to mediate between the different preferred bases in which signal and noise properties can be specified most conveniently. Using cosmic microwave background (CMB) radiation data as a showcase, we demonstrate the capabilities of our scheme by computing Wiener filtered WMAP7 temperature and polarization maps at full resolution for the first time. We show how the algorithm can be modified to synthesize fluctuation maps, which, combined with the Wiener filter solution, result in unbiased constrained signal realizations, consistent with the observations. The algorithm performs well even on simulated CMB maps with Planck resolution and dynamic range.Comment: 5 pages, 2 figures. Submitted to Astronomy and Astrophysics. Replaced to match published versio