Political Geography and Income Inequalities

This paper displays an analysis of geopolitical organizations within the framework proposed by Alesina and Spolaore (1997), where heterogeneity concerns the geographical space. This model adds heterogeneity in terms of income. Main results of the paper: (i) in the normative equilibrium (social planner solution) there is an inverse relationship between income inequality and public good provision within each jurisdiction; (ii) in the positive equilibrium (equilibrium geography) we find that in some cases there are no equilibria depending upon income inequality.Jurisdiction Size, Public Spending, Income Distribution, Tax Distortion

Imaging and 3D reconstruction of membrane protein complexes by cryo-electron microscopy and single particle analysis

Cryo-electron microscopy (cryo-EM) in combination with single particle image processing and volume reconstruction is a powerful technology to obtain medium-resolution structures of large protein complexes, which are extremely difficult to crystallize and not amenable to NMR studies due to size limitation. Depending on the stability and stiffness as well as on the symmetry of the complex, three-dimensional reconstructions at a resolution of 10-30 ˚ can be achieved. In this range of resolution, we may not be able to answer A chemical questions at the level of atomic interactions, but we can gain detailed insight into the macromolecular architecture of large multi-subunit complexes and their mechanisms of action. In this thesis, several prevalently large membrane protein complexes of great physiological importance were examined by various electron microscopy techniques and single particle image analysis. The core part of my work consists in the imaging of a mammalian V-ATPase, frozen-hydrated in amorphous ice and of the completion of the first volume reconstruction of this type of enzyme, derived from cryo-EM images. This ubiquitous rotary motor is essential in every eukaryotic cell and is of high medical importance due to its implication in various diseases such as osteoporosis, skeletal cancer and kidney disorders. My contribution to the second and third paper concerns the volume reconstruction of two bacterial outer membrane pore complexes from cryo-EM images recorded by my colleague Mohamed Chami. PulD from Klebsiella oxytoca constitutes a massive translocating pore capable of transporting a fully folded cell surface protein PulA through the membrane. It is part of the Type II secretion system, which is common for Gram-negative bacteria. The second volume regards ClyA, a pore-forming heamolytic toxin of virulent Escherichia coli and Salmonella enterica strains that kill target cells by inserting pores into their membranes. To the last two papers, I contributed with cryo-negative stain imaging of the cell division protein DivIVA from Bacillus subtilis and with image processing of the micrographs displaying the siderophore receptor FrpB from Neisseria meningitidis

Inequality, Political Systems and Public Spending

Political regimes and institutions di®er across countries. Such char- acteristics in°uence public spending within each country. The aim of this paper is to check for the existence of a link between political institu- tions, income inequality and public spending. We develop an empirical investigation, based on panel data analysis, on the determinants of pub- lic spending focusing on political, economic, demographic and social variables in large sample of developed and developing countries from 1970 to 2005. In particular, we focus on the e®ects of electoral rules on government consumption ¯nding that in countries with proportional electoral rule an increase in the heterogeneity of the government in- creases government consumption, while in countries with majoriratian electoral rule, a shift from presidential to parliamentary system leads to an increase in government consumption. We ¯nd that the link between income distribution, measured by the Gini index, and public spending depends upon institutional characteristics. Moreover, we ¯nd empiri- cal support for the argument that government spending is a policy tool used by governments to insurance the domestic economy from external shocks stemming from international trade.

Do Campaign Finance Policies Really Improve Voters' Welfare?

In an electoral race, interest groups will be willing to finance political candidates’ campaigns in return for favors that are costly to voters. Starting from the empirical observation of split contributions, we develop a theoretical model of directly informative campaign advertising with rational voters. In this setting, interest groups that demand more favors are less likely to finance candidates to enhance their electoral prospects. We find that the only feasible Pareto improving policy involves providing specific limits and subsidies to each candidate. Unfortunately, this policy is very demanding in terms of information for the policy maker and always involves candidates providing favors to interest groups. We argue that bans on contributions without public subsidies may not be welfare improving, since they negatively affect the informational value of advertisements.Campaign Finance, Interest Groups, Elections, Welfare

Political Geography and Income Inequalities

This paper studies the effect of the introduction of income inequalities in a model of geopolitical organization. We assume the existence of two groups of agents with different incomes. We focus on the policy effects of changes in income differential between the groups and changes in the fraction of the population belonging to the two groups. In the optimal solution, if size is endogenous and public good provision exogenous size increases as income inequality increases; if both size and public good provision are endogenously determined size is neutral to changes in income inequalities and public good provision decreases as inequality increases. There are cases where a stable solution does not exist and the possibility of non existence increases together with inequality, if both size and public good provision are endogenously determined.Country Size, Public Good, Income Inequality, Tax Distortion

Structure of the magnetoionic medium around the FR Class I radio galaxy 3C 449

The goal of this work is to constrain the strength and structure of the magnetic field associated with the environment of the radio source 3C 449, using observations of Faraday rotation, which we model with a structure function technique and by comparison with numerical simulations. We assume that the magnetic field is a Gaussian, isotropic random variable and that it is embedded in the hot intra-group plasma surrounding the radio source. For this purpose, we present detailed rotation measure images for the polarized radio source 3C 449, previously observed with the Very Large Array at seven frequencies between 1.365 and 8.385 GHz. We quantify the statistics of the magnetic-field fluctuations by deriving rotation measure structure functions, which we fit using models derived from theoretical power spectra. We quantify the errors due to sampling by making multiple two-dimensional realizations of the best-fitting power spectrum.We also use depolarization measurements to estimate the minimum scale of the field variations. We then make three-dimensional models with a gas density distribution derived from X-ray observations and a random magnetic field with this power spectrum. Under these assumptions we find that both rotation measure and depolarization data are consistent with a broken power-law magnetic-field power spectrum, with a break at about 11 kpc and slopes of 2.98 and 2.07 at smaller and larger scales respectively. The maximum and minimum scales of the fluctuations are around 65 and 0.2 kpc, respectively. The average magnetic field strength at the cluster centre is 3.5 +/-1.2 micro-G, decreasing linearly with the gas density within about 16 kpc of the nucleus.Comment: 19 pages; 14 figures; accepted for publication on A&A. For a high quality version use ftp://ftp.eso.org/pub/general/guidetti

Multi-Frequency Study of the B3-VLA Sample II. The Database

We present total flux densities of 1049 radio sources in the frequency range from 151 MHz to 10.6 GHz. These sources belong to the B3-VLA sample, which is complete down to 100 mJy at 408 MHz. The data constitute a homogeneous spectral database for a large sample of radio sources, 50 times fainter than the 3C catalogue, and will be used to perform a spectral ageing analysis, which is one of the critical points in understanding the physics and evolution of extragalactic radio sources.Comment: 14 pages, 3 figures, accepted for publication in Astronomy & Astrophysics Supplement Series, gzipped postscript file also available at http://multivac.jb.man.ac.uk:8000/ceres/papers/papers.html or http://gladia.astro.rug.nl:8000/ceres/papers/papers.htm

The teaching of history in secondary school in Tandil through the teachers’ story: the job of teaching and their relationship to the Curriculum Design

El objetivo del presente artículo es analizar el papel que los docentes asignan a las prescripciones curriculares, estableciendo la relación entre dichos documentos y la práctica cotidiana. A partir de la interpretación de entrevistas realizadas a un grupo de profesores, se busca estudiar los modos en que los enseñantes utilizan, descartan y/o reelaboran las prescripciones curriculares, partiendo de presuponer que los mismos tienen un rol activo en la resignificación de dichos documentos. Los resultados de la investigación indican que las resignificaciones y adaptaciones que los docentes realizan de la norma escrita varían de acuerdo a las diferentes realidades áulicas y contextuales.The aim of this paper is to analyze the role that teachers assigned to curricular requirements, establishing the relationship between these documents and everyday practice. From the interpretation of interviews with a group of teachers, is to study the ways in which teachers used, discarded and/or reworked curriculum requirements, based on assume that they have an active role in the redefinition of such documents. The research results indicate that the new meanings and adaptations that teachers do in the written standard change according to different courtly and contextual realities.Fil: Gregorini, Vanesa Mariángeles. Universidad Nacional del Centro de la Provincia de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Long-term monitoring of Molonglo calibrators

Before and after every 12 hour synthesis observation, the Molonglo Observatory Synthesis Telescope (MOST) measures the flux densities of ~5 compact extragalactic radio sources, chosen from a list of 55 calibrators. From 1984 to 1996, the MOST made some 58 000 such measurements. We have developed an algorithm to process this dataset to produce a light curve for each source spanning this thirteen year period. We find that 18 of the 55 calibrators are variable, on time scales between one and ten years. There is the tendency for sources closer to the Galactic Plane to be more likely to vary, which suggests that the variability is a result of refractive scintillation in the Galactic interstellar medium. The sources with the flattest radio spectra show the highest levels of variability, an effect possibly resulting from differing orientations of the radio axes to the line of sight.Comment: 18 pages, 9 embedded EPS files. To appear in Publications of the Astronomical Society of Australia. Data available electronically at http://www.physics.usyd.edu.au/astrop/scan