The World Trade Network

      This paper uses the tools of network analysis and graph theory to graphically and analytically represent the characteristics of world trade. The structure of the World Trade Network is compared over time, detecting and interpreting patterns of trade ties among countries. In particular, we assess whether the entrance of a number of new important players into the world trading system in recent years has changed the main characteristics of the existing structure of world trade, or whether the existing network was simply extended to a new group of countries. We also analyze whether the observed changes in international trade flow patterns are related to the multilateral or the regional liberalization policies. The results show that trade integration at the world level has been increasing but it is still far from being complete, with the exception of some areas, that there is a strong heterogeneity in the countries’ choice of partners, and that the WTO plays an important role in trade integration. The role of the extensive and the intensive margin of trade is also highlighted.Network analysis,International Trade,WTO,Extensive and Intensive Margins of Trade,Gravity

Similarity in export composition and catching-up

In this paper we look at the role of export composition in the growth process, considering how increased similarity in trade structure among countries can induce catching-up in income levels. We apply our analysis to the Central and Eastern European Countries (CEECs) using the EU as a benchmark. We explicitly consider the sectoral export patterns of the CEECs by comparing them to those of the current members of the EU, focusing on countries' specialization as suppliers for the EU market. Our main result is that similarity in export composition has a positive, significant and nonlinear impact on catching-up, and seems to be driven by the growth of the main export market more than by other factors. Results are robust to controlling for openness and country-size and for investment, schooling, and the quality of institutions.EU enlargement,CEECs,,growth,,export composition,

Two-component galaxies with flat rotation curve

Dynamical properties of two-component galaxy models whose stellar density distribution is described by a gamma-model while the total density distribution has a pure r^(-2) profile, are presented. The orbital structure of the stellar component is described by Osipkov-Merritt anisotropy, while the dark matter halo is isotropic. After a description of minimum halo models, the positivity of the phase-space density (the model consistency) is investigated, and necessary and sufficient conditions for consistency are obtained analytically as a function of the stellar inner density slope gamma and anisotropy radius. The explicit phase-space distribution function is recovered for integer values of gamma, and it is shown that while models with gamma>4/17 are consistent when the anisotropy radius is larger than a critical value (dependent on gamma), the gamma=0 models are unphysical even in the fully isotropic case. The Jeans equations for the stellar component are then solved analytically; in addition, the projected velocity dispersion at the center and at large radii are also obtained analytically for generic values of the anisotropy radius, and it is found that they are given by remarkably simple expressions. The presented models, even though highly idealized, can be useful as starting point for more advanced modeling of the mass distribution of elliptical galaxies in studies combining stellar dynamics and gravitational lensing.Comment: 11 pages, 5 figures, accepted by MNRA

Conflict, law and economy in the European Union after the crisis

The economic and financial crisis has led to profound changes, which also concern relations between the European Union and its Member States in the area of so-called economic governance. Thanks to two concepts developed by Michel Foucault –the pastorate and the disciplinary power– this essay examines the nature, scope and consequences of some of these constitutional changes.La crisis económica y financiera ha dado lugar a profundas transformaciones, relativas también a las relaciones entre la Unión Europea y los Estados miembros en el ámbito de la llamada gobernanza económica. Gracias a dos conceptos elaborados por Michel Foucault –el pastorado y el poder disciplinario–, este ensayo examina la naturaleza, el alcance y las consecuencias de algunos de esos cambios constitucionales

Statics and dynamics of dislocations: a variational approach

Dislocations are line defects in the periodic structure of the crystals. In this thesis, we focus the variational analysis of the elastic energy induced by a finite family of dislocations. Moreover, we study the dynamics of a finite system of screw dislocations

Statics and dynamics of dislocations: a variational approach

Dislocations are line defects in the periodic structure of the crystals. In this thesis, we focus the variational analysis of the elastic energy induced by a finite family of dislocations. Moreover, we study the dynamics of a finite system of screw dislocations

N-acylphosphatidylethanolamines, N-acylethanolamines and Endocannabinoids: dietary sources and fate during digestion in humans

N-acylphosphatidylethanolamines (NAPEs), N-acylethanolamines (NAEs) and Endocannabinoids (ECs) are bioactive molecules that participate to the hedonic and homeostatic phenomena underpinning food intake. NAEs and ECs have a wide range of biochemical effects and derive from hydrolysis of NAPEs. NAEs and ECs are involved in different biological pathways since they are agonists of cannabinoid receptor-1 (CB1), transient receptor potential vanilloid 1 (TRPV1) and the peroxisome proliferator-activated receptor-α (PPAR-α). Moreover, NAEs are also able to link GPR119 which is expressed on cells in the small intestine, colon and stomach. The receptors are involved in food intake and in blood glucose control due to the regulation from the gastrointestinal tract (GIT) of GLP-1 secretion. Although NAPEs, NAEs and ECs are compounds widespread in nature, only few studies reported the amount of ECs and NAEs in some food products. The gut microbiota is able to control levels of ECs in both the gut and the adipose tissue in obese mice. In humans, a relationship between the changes in the gut microbiota and in the ECs system tone is not yet demonstrated. The studies described in this PhD thesis investigated the presence of NAPEs, NAEs and ECs in foods and tested their bioaccessibility in the oral cavity during food mastication in vivo and in the GIT in vitro to evaluate their potential availability to activate the receptors present on the alimentary canal mucosa. In the chapter 2 the concentration of NAPEs, NAEs and ECs in foods of different origin was assessed and the daily intakes upon a Mediterranean (MD), Vegetarian (VD) and Western diet (WD) were calculated. Data showed that NAPEs and NAEs were more abundant in vegetal than in animal food products. The estimated daily intake of NAPEs was in the order of hundreds milligrams with abundance being in MD=VD>WD. The intake of NAEs and ECs were in the order of hundreds or tens micrograms; the abundance of NAEs was in MD=VD>WD, while that of ECs was in MD=WD>VD. In the chapter 3 a sham feeding study was described. It showed the concentration of NAEs in stimulated saliva of healthy normal weight subjects. Interestingly, salivary concentration of NAEs increased upon food mastication compared to the mastication of a parafilm piece (stimulated saliva). The concentration of NAEs in the oral cavity within the first hours after food mastication was influenced by the type of dietary fiber (3% of β-glucan or whole-wheat bran) used for the preparation of biscuits. In the chapter 4 another sham feeding study was described. It aimed at evaluating the influence of individual nutritional status on bioaccessibility (release in saliva) of NAPEs and NAEs upon mastication of three biscuits differing for amount and type of fat. To this purpose three types of biscuits were prepared with 8% of extravirgin olive oil (EVOB), 8% of palm oil (PALMB) and without added fat (CONB). Data showed that the obese (OB) subjects had a higher release of NAPEs in unstimulated saliva than normal weight (NW) subjects, while the concentration of NAEs in both unstimulated saliva and stimulated saliva was higher in OB than in NW subjects. During the mastication of biscuits a higher concentration of salivary NAPEs and NAEs than a no food condition in both NW and OB subjects was found. In the chapter 5 the bioaccesibility of NAEs and ECs along the gastrointestinal tract in vitro using Simulator of the Human Intestinal Microbial Ecosystem (SHIME®) simulating both physiological conditions and the microbial ecosystem found in the ascending (AC), transverse (TC) and descending (DC) colon was assessed. To this purpose we prepared two different diets: Mediterranean (MD) and Western diet (WD) and the supernatants deriving from the different phase of colon were analyzed by HRMS analysis to measure NAEs and ECs. Data showed that the diets did not influence the concentration of these compounds, but the microbiota composition could influence the release of compounds in the colon phase. Considering the results obtained from the experiments performed in this PhD thesis it is possible to conclude that: 1) NAPEs, NAEs and ECs are present in many food products at different concentrations. 2) In vivo studies showed that these compounds are released from food matrix during the mastication and that other food components (fibers and fats) as well as the individual nutritional status of individuals may influence both the delivery of these compounds from the food (bioaccessibility) as well as their persistence in the oral cavity after eating; this might influence liking of food and subsequent food intake. 3) During in vitro digestion with SHIME® the concentration of NAPEs, NAEs and ECs was hypothesized to be majorly influenced by the microbiota composition inside the system acting on the biosynthesis and degradation of NAEs and ECs arriving into the colon, independently from the diet. Specifically designed studies are necessary to elucidate better the influence of enzymatic activity of NAPE-PLD and FAAH at different sites of the alimentary canal and in the gut microbiota to ascertain the metabolic fate of dietary NAPEs, NAEs and ECS in vivo and to possibly find dietary strategy to modulate the concentration of these bioactive compounds at intestinal level

Γ\Gamma-convergence analysis of a generalized XYXY model: fractional vortices and string defects

We propose and analyze a generalized two dimensional $XY$ model, whose interaction potential has $n$ weighted wells, describing corresponding symmetries of the system. As the lattice spacing vanishes, we derive by $\Gamma$-convergence the discrete-to-continuum limit of this model. In the energy regime we deal with, the asymptotic ground states exhibit fractional vortices, connected by string defects. The $\Gamma$-limit takes into account both contributions, through a renormalized energy, depending on the configuration of fractional vortices, and a surface energy, proportional to the length of the strings. Our model describes in a simple way several topological singularities arising in Physics and Materials Science. Among them, disclinations and string defects in liquid crystals, fractional vortices and domain walls in micromagnetics, partial dislocations and stacking faults in crystal plasticity