The B3-Vla CSS sample. III: Evn & Merlin images at 18 cm

EVN and MERLIN observations at 18 cm are presented for 18 Compact Steep--spectrum radio Sources (CSSs) from the B3-VLA CSS sample. These sources were marginally resolved in previous VLA A-configuration observations at 4.9 and 8.4 GHz or had peculiar morphologies, two of them looking like core-jets. The MERLIN images basically confirm the VLA structures at 8.4 GHz while the EVN and/or the combined images reveal several additional details.Comment: 17 pages, many low resoltion figures, A&A accepted. A higher resolution gzipped postscript file can be found at http://www.ira.cnr.it/~ddallaca/h3443.ps.g

Synchrotron Spectra and Ages of Compact Steep Spectrum Radio Sources

The high-frequency integrated spectra of Compact Steep Spectrum (CSS) sources show breaks with a moderate spectral steepening well fitted by continuous injection synchrotron spectra. In lobe-dominated CSS sources the radiative ages deduced by the synchrotron theory are in the range of up to 0.1 Myears, if equipartition magnetic fields are assumed. These radiative ages are well correlated with the source size indicating that the CSS sources are young. In order to maintain the frustration scenario, in which the sources' lifetimes are about 10 Myears, their equipartition magnetic field would be systematically decreased by a factor of more than 20. To complete the sample used in this work, we conducted observations at 230 GHz with the IRAM 30-m telescope of those sources which did not have such high-frequency observations up to now.Comment: 10 pages, 6 figures, 2 tables, accepted for publication in Astron. & Astrophys.; typos corrected; gzipped postscript version also available at: http://multivac.jb.man.ac.uk:8000/ceres/papers/papers.html http://gladia.astro.rug.nl:8000/ceres/papers/papers.htm

Longevity, fertility and Demographic Transition in an OLG model.

The paper investigates the effects of declining mortality on fertility and income in the standard OLG neoclassical growth model under the assumptions of accidental bequests as well as fully annuitised savings. It is shown whether and how different countries may expect increasing or decreasing fertility rates under increasing longevity, and argued that mortality decline may be another explanation of the Demographic Transition process. In particular, the fact that some countries have completed the process while others are entrapped in the second stage may depend on the initial level of mortality as well as on differences in technology and preferences. It is also argued that the third stage may not necessarily occur in some less developed countries even if their mortality rates converge towards those of industrialised countries.longevity

Rich Cluster and Non-Cluster Radio Galaxies & the (P,D) Diagram for a Large Number of FR I and FR II Sources

We present a comparison of the optical and radio properties of radio sources inside and outside the cores of rich clusters from combined samples of more than 380 radio sources. We also examine the nature of FR I and FR II host galaxies, and in particular, we illustrate the importance of selection effects in propagating the misconception that FR I's and FR II's are found in hosts of very different optical luminosity. Given the large sample size, we also discuss the power-size (P,D) distributions as a function of optical luminosity.Comment: to appear in Life Cycles of Radio Galaxies, ed. J. Biretta et al., New Astronomy Reviews; 6 pages, including 2 figure

Public health spending, old-age productivity and economic growth: chaotic cycles under perfect foresight

This paper analyses the dynamics of a double Cobb-Douglas economy with overlapping generations and public health investments that affect the supply of efficient labour of the old-aged. It is shown that the positive steady state of the economy is unique. Moreover, we provide necessary and sufficient conditions for the emergence of endogenous deterministic complex cycles when individuals are perfect foresighted. Interestingly, the equilibrium dynamics shows rather complicated phenomena such as a multiplicity of period-bubbling.OLG model; Productivity; Perfect foresight; Public health expenditure

Profits and Competition in a Unionized Duopoly Model with Product Differentiation and Labour Decreasing Returns

In this paper, we aim at investigating if the conventional wisdom, that an increase of competition linked to a decrease in the degree of product differentiation always reduces firms’ profits, remains true in a unionized duopoly model with labour decreasing returns. In this context, mixed results emerge. In particular, we show that a decrease in the degree of product differentiation may affect wages, hence profits, differently, depending on both the mode of competition in the product market (Cournot or Bertrand competition) and the particular unionization structure (firm-specific or industry-wide union(s)). Interestingly, it is shown that the conventional wisdom can actually be reversed, even if under Bertrand competition only.unionized duopoly, labour decreasing returns, product differentiation, profits

Differentiated Duopoly and Horizontal Merger Profitability under Monopoly Central Union and Convex Costs

Can a merger from duopoly to monopoly be detrimental for profits? This paper deals with this issue by focusing on the interaction between decreasing returns to labour (which imply firms’ convex production costs) and centralised unionisation in a differentiated duopoly model. It is pointed out that the wage fixed by a monopoly central union in the post-merger case is higher than in the pre-merger/Cournot equilibrium, opening up the possibility that merger reduces profits. Indeed, it is shown that this “reversal result” actually applies when the central union is sufficiently little interested to wages with respect to employment. Moreover, the lower the degree of substitutability between firms’ products and the higher the workers’ reservation wage, the higher ceteris paribus the probability that profits decrease as a result of the merger.merger profitability, unionised duopoly, convex costs

The Cournot-Bertrand profit differential in a differentiated duopoly with unions and labour decreasing returns

This paper compares Cournot and Bertrand equilibria in a differentiated duopoly, total wage bill maximizing unions and labour decreasing returns. It is shown that the standard result, that equilibrium profits are always higher under Cournot, may be reversed even for a fairly low degree of product differentiation. Moreover, the presence of diminishing returns to labour tends to reinforce the mechanisms that contribute to the reversal result, making this event possible for a wider range of situations, with respect to those identified by the earlier literature.Cournot-Bertrand profit differential, unions, labour decreasing returns

Extended emission around GPS radio sources

Extended radio emission detected around a sample of GHz Peaked Spectrum (GPS) radio sources is discussed. Evidence for extended emission which is related to the GPS source is found in 6 objects out of 33. Three objects are associated with quasars with core-jet pc-scale morphology, and three are identified with galaxies with symmetric (CSO) radio morphology. We conclude that the core-jet GPS quasars are likely to be beamed objects with a continuous supply of energy from the core to the kpc scale. It is also possible that low surface brightness extended radio emission is present in other GPS quasars but the emission is below our detection limit due to the high redshifts of the objects. On the other hand, the CSO/galaxies with extended large scale emission may be rejuvenated sources where the extended emission is the relic of previous activity. In general, the presence of large scale emission associated with GPS galaxies is uncommon, suggesting that in the context of the recurrent activity model, the time scale between subsequent bursts is in general longer than the radiative lifetime of the radio emission from the earlier activity.Comment: 18 paged, 18 figures, accepted for publication on A&