Spatial Externalities and Empirical Analysis: The case of Italy

In the last ten years the space issue, i.e. the study of the role played by space in economic phenomena, has attracted a lot of interest from many economic fields. Both the suitability of spatial economics to address questions posed by globalization, and improves in modeling techniques are at the basis of this revolution. The combination of increasing returns, market imperfections, and trade costs creates new forces that, together with factor endowments, determine the distribution of economic activities. These spatial externalities makes agents' location choice highly interdependent, thus allowing to understand the empirical spatial correlation between demand and production previously observed by the market potential literature. Despite their theoretical relevance, there is still little evidence, especially at large scale level, on the effective contribution of this new identified forces to agents' location decisions. The aim of this work is to directly estimate a model of economic geography on some Italian regional data in order to both test the empirical relevance of this theory and try to give a measure of the geographic extent of spatial externalities.Economic Geography; Spatial Externalities; Market Potential

Drammaturgie musicali per la Settimana Santa in Sicilia

Nel ricco complesso delle cerimonie della Settimana Santa siciliana, la musica e i canti rivestono ruoli primari nell'accompagnare i momenti rituali in cui attraverso vere e proprie rappresentazioni drammatiche viene ricordata la passione di Cristo e la sua resurrezione. Il contributo si sofferma su alcuni esempi particolarmente rappresentativi sotto il profilo musicale e drammaturgico, offrendo al contempo diversi spunti di riflessione sul rapporto tra liturgia canonica e rito popolare: occasioni privilegiate in cui azione scenica e musica si fondono per dar vita a vere e proprie rappresentazioni drammatiche

A New Dimension in the Factorial Techniques: the Response Surface

In this paper we propose to bring together some facets of the Response Surface Methodology used in Design of Experiments and the graphical displays arising from Multidimensional Data Analysis in order to enhance the interpretation of the traditional plots of the Factorial Techniques. By exploiting the peculiar interpretation of a response surface we describe a data-fitting based approach in order to analyse the relationships between an outer quantitative response variable and a set of principal axes. Moreover, we to use this interpretative-aid tool to represent by a surface response the information about the quality of the representation derived by a multidimensional data analysi

Assessment of a calibration procedure to estimate soil water content with Sentek Diviner 2000 capacitance probe

In irrigated systems, soil water content is a major factor determining plant growth. Irrigation scheduling criteria are often related to measurements of soil water content or matric potential. Strategies to manage irrigation can be used to optimize irrigation water use or to maximize crop yield and/or quality, in order to increase the net return for the farmer. Of course, whatever criterion is adopted to schedule irrigation and in particular when crop water stress conditions are considered, the accurate monitoring of the water content in the soil profile, could allow to verify the exact irrigation timing, defined according to the crop response to water stress. Currently many methods are available for determining soil water content on a volume basis (m3m-3) or a tension basis (MPa), as described by Robinson (2008). Recently, distributed fiber optic temperature measurement, has been assessed as a new technique for indirect and precise estimation of soil water contents. Over the past decade Frequency Domain Reflectometry (FDR) probes, allowing to measure the apparent dielectric constant of the soil (K), indirectly related to the volumetric water content (θv), have been improved, due to the good potentiality of capacitance based sensors to in situ measurements of soil water content. However, due to the high variability of K with soil minerals and dry plants tissues, it necessary to proceed to a specific calibration of the sensor for each soil (Baumhardt et al., 2000), even to take into account the effect of soil temperature, bulk density and water salinity (Al Ain et al., 2009). . According to Paltineanu and Starr (1997), the precision of the calibration equation, obtained with in situ measurements, mainly depends on the errors related to the sampling of the soil volume investigated by the sensor, that must be done accurately. For swelling/shrinking soils, the changes of soil bulk volume with water content cause modifications in the geometry of some if not all the soil pores, affecting the bulk density/water content relationship (Allbrook, 1992). Field experiments in shrinking-swelling clay soils evidenced that soil water content can be affect by errors of 20-30% if the soil shrinkage curve is not considered (Fares et al., 2004). The main objective of the paper was to propose a practical calibration procedure for FDR sensor using minilysimeter containing undisturbed soil, allowing to take in to account the possible variations of the bulk density with the soil water content. Moreover, the possibility of using disturbed soil samples for determining the sensor calibration curve was also investigated, in order to simplify the proposed methodology. Experiments were carried out on three different soil, two of which containing a percentage of clay higher than 40%, in order to compare the specific calibration curves with that suggested by the manufactures. The investigation showed how for swelling/shrinkage soils it is necessary the knowledge of the actual soil bulk density and also that using disturbed soil sample is not possible to consider the effects of the soil shrinkage consequent to the soil water content reductions

Social Capital and Self-rated Health: testing association with longitudinal and multilevel methodologies

Since Durkheim’s seminal work over a century ago, research has repeatedly shown that individuals with higher levels of social integration, social networks and social support have better health status. However, the recent introduction of a contextual phenomenon known as social capital to the field of public health has sparked lively debate as to how it may also influence the health of individuals, if at all. Though critics have raised several points of contention regarding reported association between social capital and health over recent years, one outstanding issue remains: the lack of empirical research focusing on causal relationships, due to paucity of adequate longitudinal social capital data. The overall aim of this thesis is to test association between different social capital proxies and self-rated health (SRH), alongside other well-known health determinants, using multilevel and longitudinal data, whilst employing a variety of study designs and methods. All data used in this thesis come from the United Kingdom’s British Household Panel Survey (BHPS) from years 2000, 03, 05, 07 and 08. The underlying premise of this body of work is to investigate temporal (causal) relationships between social capital and health. All four papers of this thesis demonstrate that generalised trust is the most robust of all social capital proxies tested, it maintaining a positive association with SRH over time. Furthermore, results from paper III imply that prior trust levels can predict future SRH, lending weight to the hypothesis that trust is an independent determinant of health. However, debate remains as to whether generalised trust solely captures social capital or other, more tangible aspects of social cohesion

Strip Planarity Testing of Embedded Planar Graphs

In this paper we introduce and study the strip planarity testing problem, which takes as an input a planar graph $G(V,E)$ and a function $\gamma:V \rightarrow \{1,2,\dots,k\}$ and asks whether a planar drawing of $G$ exists such that each edge is monotone in the $y$-direction and, for any $u,v\in V$ with $\gamma(u)<\gamma(v)$, it holds $y(u)<y(v)$. The problem has strong relationships with some of the most deeply studied variants of the planarity testing problem, such as clustered planarity, upward planarity, and level planarity. We show that the problem is polynomial-time solvable if $G$ has a fixed planar embedding.Comment: 24 pages, 12 figures, extended version of 'Strip Planarity Testing' (21st International Symposium on Graph Drawing, 2013

Consistency aspects of Wiener-Hammerstein model identification in presence of process noise

The Wiener-Hammerstein model is a block-oriented model consisting of two linear blocks and a static nonlinearity in the middle. Several identification approaches for this model structure rely on the fact that the best linear approximation of the system is a consistent estimate of the two linear parts, under the hypothesis of Gaussian excitation. But, these approaches do not consider the presence of other disturbance sources than measurement noise. In this paper we consider the presence of a disturbance entering before the nonlinearity (process noise) and we show that, also in this case, the best linear approximation is a consistent estimate of underlying linear dynamics. Furthermore, we analyse the impact of the process noise on the nonlinearity estimation, showing that a standard prediction error method approach can lead to biased results

Critical behaviour of the O(3) nonlinear sigma model with topological term at theta=pi from numerical simulations

We investigate the critical behaviour at theta=pi of the two-dimensional O(3) nonlinear sigma model with topological term on the lattice. Our method is based on numerical simulations at imaginary values of theta, and on scaling transformations that allow a controlled analytic continuation to real values of theta. Our results are compatible with a second order phase transition, with the critical exponent of the SU(2)_1 Wess-Zumino-Novikov-Witten model, for sufficiently small values of the coupling.Comment: Revised version. 24 pages, 7 figure