The NOD3 software package: A graphical user interface-supported reduction package for single-dish radio continuum and polarisation observations

The venerable NOD2 data reduction software package for single-dish radio continuum observations, developed for use at the 100-m Effelsberg radio telescope, has been successfully applied over many decades. Modern computing facilities call for a new design. We aim to develop an interactive software tool with a graphical user interface (GUI) for the reduction of single-dish radio continuum maps. Special effort is given on the reduction of distortions along the scanning direction (scanning effects) by combining maps scanned in orthogonal directions or dual- or multiple-horn observations that need to be processed in a restoration procedure. The package should also process polarisation data and offer the possibility to include special tasks written by the individual user. Based on the ideas of the NOD2 package we developed NOD3, which includes all necessary tasks from the raw maps to the final maps in total intensity and linear polarisation. Furthermore, plot routines and several methods for map analysis are available. The NOD3 package is written in Python which allows to extend the package by additional tasks. The required data format for the input maps is FITS. NOD3 is a sophisticated tool to process and analyse maps from single-dish observations that are affected by 'scanning effects' due to clouds, receiver instabilities, or radio-frequency interference (RFI). The 'basket-weaving' tool combines orthogonally scanned maps to a final map that is almost free of scanning effects. The new restoration tool for dual-beam observations reduces the noise by a factor of about two compared to the NOD2 version. Combining single-dish with interferometer data in the map plane ensures the full recovery of the total flux density.Comment: 8 pages, 10 figures, Accepted for publication in A&

Synchrotron spectral index and interstellar medium densities of star-forming galaxies

The spectral index of synchrotron emission is an important parameter in understanding the properties of cosmic ray electrons (CREs) and the interstellar medium (ISM). We determine the synchrotron spectral index ($\alpha_{\rm nt}$) of four nearby star-forming galaxies, namely NGC 4736, NGC 5055, NGC 5236 and NGC 6946 at sub-kpc linear scales. The $\alpha_{\rm nt}$ was determined between 0.33 and 1.4 GHz for all the galaxies. We find the spectral index to be flatter ($\gtrsim -0.7$) in regions with total neutral (atomic + molecular) gas surface density, $\Sigma_{\rm gas} \gtrsim \rm 50~M_\odot pc^{-2}$, typically in the arms and inner parts of the galaxies. In regions with $\Sigma_{\rm gas} \lesssim \rm 50~M_\odot pc^{-2}$, especially in the interarm and outer regions of the galaxies, the spectral index steepens sharply to $<-1.0$. The flattening of $\alpha_{\rm nt}$ is unlikely to be caused due to thermal free--free absorption at 0.33 GHz. Our result is consistent with the scenario where the CREs emitting at frequencies below $\sim0.3$ GHz are dominated by bremsstrahlung and/or ionization losses. For denser medium ($\Sigma_{\rm gas} \gtrsim \rm 200~M_\odot pc^{-2}$), having strong magnetic fields ($\sim 30~\mu$G), $\alpha_{\rm nt}$ is seen to be flatter than $-0.5$, perhaps caused due to ionization losses. We find that, due to the clumpy nature of the ISM, such dense regions cover only a small fraction of the galaxy ($\lesssim5$ percent). Thus, the galaxy-integrated spectrum may not show indication of such loss mechanisms and remain a power-law over a wide range of radio frequencies (between $\sim 0.1$ to 10 GHz).Comment: 10 pages, 4 figures, 2 tables, Accepted to be published in MNRA

New tools and new tests in comparative political economy - the database of political institutions

This paper introduces a large new cross-country database on political institutions: the Database on Political Institutions (DPI). The authors summarize key variables (many of them new), compare this data set with others, and explore the range of issues for which the data should prove invaluable. Among the novel variables they introduce: 1) Several measures of tenure, stability, and checks and balances. 2) Identification of parties with the government coalition or the opposition. 3) Fragmentation of opposition and government parties in legislatures. The authors illustrate the application of DPI variables to several problems in political economy. Stepan and Skach, for example, find that democracy is more likely to survive under parliamentary governments than presidential systems. But this result is not robust to the use of different variables from the DPI, which raises puzzles for future research. Similarly, Roubini and Sachs, find that divided governments in the OECD run higher budget deficits after fiscal shocks. Replication of their work using DPI indicators of divided government indicates otherwise, again suggesting issues for future research. Among questions in political science and economics, that this database may illuminate: the determinants of democratic consolidation, the political conditions for economic reform, the political and institutional roots of corruption, and the elements of appropriate and institutionally sensitive design of economic policy.Decentralization,Parliamentary Government,National Governance,Information Technology,ICT Policy and Strategies,National Governance,Parliamentary Government,ICT Policy and Strategies,Information Technology,Governance Indicators

Megarian Moments. The Local World of an Ancient Greek City-State

Situated near the main traffic artery in Central Greece and surrounded by poleis that were more powerful, the ancient city-state of Megara was often a punching bag of others. In neighbouring Athens in particular, the Megarians were subject to all sorts of slander and expressions of chauvinism. The people of Megara, by default, had their own assessment of the world and their role in it. A highway to others, the Megarid, was a rich source of meaning and orientation to its inhabitants. This local backdrop, often misunderstood as petty or irrelevant, constituted a unique local discourse environment. Rather than telling a narrative history of Megara – unravelling its local history, as it were –, this volume delves into the local discourse of this ancient city. The various contributions all shed light on the prevailing identity of place, on what it meant to be from Megara. In doing so, the book unpacks the vibrant local life in a Greek city-state. In their endeavour to break the code of a local discourse and recreate its environment, the editors and authors also invite readers to rethink approximations toward the pluriverse of poleis in Greek Antiquity