Stochastic convergence among European economies

The aim of this paper is to test the stochastic convergence in real per capita GDP for 15 European countries using non-stationary panel data approaches over the period 1950-2003. Cross-sectional dependence is assumed due to the existence of strong linkages among European economies. However, tests derived under the assumption of cross-sectional independence are also carried out for completeness and comparison. We also split the whole sample into two sub-periods (1950-1976, 1977-2003) in order to take into account the effects of the first oil crisis (1973-1974) and to evaluate the robustness of the statistical analysis. Our results offer little support to the stochastic convergence hypothesis for the whole period, while suggest the presence of convergence in the first sub-period.Convergence

A Simple Panel-CADF Test for Unit Roots

In this paper we propose a simple extension to the panel case of the covariate-augmented Dickey Fuller (CADF) test for unit roots developed in Hansen (1995). The extension we propose is based on a p-values combination approach that takes into account cross-section dependence. We show that the test is easy to compute, has good size properties and gives power gains with respect to other popular panel approaches. A procedure to compute the asymptotic p-values of Hansen’s CADF test is also a side-contribution of the paper. We also complement Hansen (1995) and Caporale and Pittis (1999) with some new theoretical results. Two empirical applications are carried out for illustration purposes on international data to test the PPP hypothesis and the presence of a unit root in international industrial production indices.Unit root, panel data, approximate p-values, Monte Carlo

New species of Dolichopoda Bolívar, 1880 (Orthoptera, Rhaphidophoridae) from the Aegean Islands of Andros, Paros and Kinaros (Greece)

In this paper two new species of Dolichopoda Bolívar, 1880 from the Cyclades islands of Andros and Paros and one from the Dodecanissos island of Kinaros, are described, increasing the total number of Greek species to 32. The new species from Paros (D. kikladica Di Russo & Rampini, n. sp.) and Kinaros (D. margiolis Di Russo & Rampini, n. sp.) show strong similarities with D. naxia Boudou-Saltet, 1972 from Naxos forming an homogenous group limited to the central Aegean islands. On the other hand the species D. christos-nifoni Di Russo & Rampini, n. sp. from Andros shows a combination of morphological characters that partly resemble characters found in Evvian Dolichopoda, and partly in species from the Cyclades. Relationships among these three new taxa and the other adjacent Dolichopoda species are discussed on the basis of the paleogeological and paleoclimatic events that shaped the present geography of the Aegean area

A Simple Panel-CADF Test for Unit Roots

In this paper we propose a simple extension to the panel case of the covariate- augmented Dickey Fuller (CADF) test for unit roots developed in Hansen (1995). The extension we propose is based on a p values combination approach that takes into account cross-section dependence. We show that the test is easy to compute, has good size properties and gives power gains with respect to other popular panel approaches. A procedure to compute the asymptotic p values of Hansen's CADF test is also a side-contribution of the paper. We also complement Hansen (1995) and Caporale and Pittis (1999) with some new theoretical results. Two empirical applications are carried out for illustration purposes on international data to test the PPP hypothesis and the presence of a unit root in international industrial production indices.Unit Root, Panel data, Approximate p values, Monte Carlo

Relative partition function of Coulomb plus delta interaction

The relative partition function and the relative zeta function of the perturbation of the Laplace operator by a Coulomb potential plus a point interaction centered in the origin is discussed. Applications to the study of the Casimir effect are indicated.Comment: Minor misprints corrected. 24 page

Simplicial Aspects of String Dualities

We will show how the study of randomly triangulated surfaces merges with the study of open/closed string dualities. In particular we will discuss the Conformal Field Theory which arises in the open string sector and its implications.Comment: 3 pages, to appear in the proceeding of the conference XVI SIGRAV - Vietri sul Mar

Narrowband delay tolerant protocols for WSN applications. Characterization and selection guide

This article focuses on delay tolerant protocols for Wireless Sensor Network (WSN) applications, considering both established and new protocols. We obtained a comparison of their characteristics by implementing all of them on an original platform for network simulation, and by testing their behavior on a common test-bench. Thereafter, matching the requirements linked to each application with the performances achieved in the test-bench, allowed us to define an application oriented protocol selection guide