Trade balance and terms of trade in U.S.: a time-scale decomposition analysis

The aim of this paper is to provide evidence on the nature of the relationship between the terms of trade and the trade balance for US on a scale-by-scale basis using wavelet analysis. Thus, after decomposing the two variables into their time-scale components using to the maximum overlap discrete wavelet transform (MODWT) we analyze the time scale relationships between the terms of trade and the trade balance through the wavelet correlation analysis, and nonparametric regression models(GAMs). Wavelet correlation analysis indicates that, if the association between the trade balance and the terms of trade depends mainly on the elasticity of substitution between foreign and domestic goods, the Armington elasticities may be di¤erent across scales, and in particular, tend to get larger as the time horizon of the agents increases. Moreover, the long-run relationship between the trade balance and the terms of trade from the nonparametric …tted functions seems to provide support to the existence of the Harberger-Laursen-Metzler e¤ect .trade variables, wavelet correlation analysis, generalized additive models

Formal Analysis of Vulnerabilities of Web Applications Based on SQL Injection (Extended Version)

We present a formal approach that exploits attacks related to SQL Injection (SQLi) searching for security flaws in a web application. We give a formal representation of web applications and databases, and show that our formalization effectively exploits SQLi attacks. We implemented our approach in a prototype tool called SQLfast and we show its efficiency on real-world case studies, including the discovery of an attack on Joomla! that no other tool can find

Linear and Branching System Metrics

We extend the classical system relations of trace\ud inclusion, trace equivalence, simulation, and bisimulation to a quantitative setting in which propositions are interpreted not as boolean values, but as elements of arbitrary metric spaces.\ud \ud Trace inclusion and equivalence give rise to asymmetrical and symmetrical linear distances, while simulation and bisimulation give rise to asymmetrical and symmetrical branching distances. We study the relationships among these distances, and we provide a full logical characterization of the distances in terms of quantitative versions of LTL and μ-calculus. We show that, while trace inclusion (resp. equivalence) coincides with simulation (resp. bisimulation) for deterministic boolean transition systems, linear\ud and branching distances do not coincide for deterministic metric transition systems. Finally, we provide algorithms for computing the distances over finite systems, together with a matching lower complexity bound

Overall Specialization and Income: Countries Diversity

� � � This paper gives evidence to a stylized fact often disregarded in international trade empir- ics: countries' diversification. In the last fifteen years, the growth of world trade coexisted with the tendency of countries to reduce the specialization of their export composition along the development path. On average, countries do not specialize, they diversify. Our semiparametric empirical analysis shows how this result is robust to the use of different statistical indexes used to measure trade specialization to the level of sectoral aggrega- tion and to the level of smoothing in the nonparametric term associated to income per capita. Using a General Additive Model (GAM) with country-specific fixed-effect, we show that, controlling for countries heterogeneity, sectoral export diversification increases with income. �Nonparametrics,International Trade,Specialization

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

Overall Specialization and Income: Countries Diversify

This paper gives evidence to a stylized fact often disregarded in international trade empirics: countries' diversification. In the last fifteen years, the growth of world trade coexisted with the tendency of countries to reduce the specialization of their export composition along the development path. On average, countries do not specialize, they diversify. Our semiparametric empirical analysis shows how this result is robust to the use of different statistical indexes used to measure trade specialization to the level of sectoral aggregation and to the level of smoothing in the nonparametric term associated to income per capita. Using a General Additive Model (GAM) with country-specific fixed-effect, we show that, controlling for countries heterogeneity, sectoral export diversification increases with income.International Trade, Specialization, Development, Generalized Additive Models

Ground states of a two phase model with cross and self attractive interactions

We consider a variational model for two interacting species (or phases), subject to cross and self attractive forces. We show existence and several qualitative properties of minimizers. Depending on the strengths of the forces, different behaviors are possible: phase mixing or phase separation with nested or disjoint phases. In the case of Coulomb interaction forces, we characterize the ground state configurations

An atypical case of trigeminal trophic syndrome: a legal medicine perspective in medical responsibility

BACKGROUND: Trigeminal trophic syndrome is a rare complication of peripheral or central damage to the trigeminal nerve characterized by anesthesia, paresthesia and a secondary persistent facial ulceration. METHODS: We describe the case of a 40-year-old woman with previous history of Le Fort I osteotomy for a class III malocclusion who developed trigeminal trophic syndrome. Atypically, the cutaneous symptoms appeared bilaterally and 8 years after surgery. RESULTS: Differential diagnosis was based on clinical history, tissue biopsy and serologic evaluation. Atypical findings could be linked to the surgical burdens of Le Fort I osteotomy, a procedure characterized by a bilateral incision on the maxillofacial bones with a reasonable probability of causing a bilateral injury of the peripheral branches of the trigeminal nerve. CONCLUSION: Although the long delay between trigeminal trophic syndrome onset and surgery and the absence of adequate medical evidence cannot confirm a link with previous surgery in this case, the increasing number of maxillofacial surgery cases suggests that this complication may be more frequent in the next decades, and thus, involved specialists should be aware of this condition as a possible complication of maxillofacial surgery procedures

Reduction of gait abnormalities in type 2 diabetic patients due to physical activity: a quantitative evaluation based on statistical gait analysis

The aim of this study is the objective assessment of gait abnormalities in diabetic patients and the quantification of the benefits of physical activity in improving the gait quality. Patients were equipped with foot-switches and knee goniometers and were asked to walk at their natural pace for 2.5 minutes. A statistical gait analysis was performed extracting from hundreds of strides the ‘atypical' cycles, i.e. the cycles which do not show the usual sequence of gait phases (heel contact, flat foot contact, push off, swing), the duration of the heel contact phase and the knee kinematics in the sagittal plane. A sample population of 27 non-neuropathic type 2 diabetic patients was examined before and after attending a light-intensity physical activity program that lasted four months. A fuzzy classifier was used to assign a score to the gait abnormalities of each patient in baseline conditions and after the program completion. More than 50% of the subjects reduced significantly their gait abnormalities and, on the average, the most frequent improvements were the reduction of atypical cycles and heel contact duration. Furthermore we found that, in basal conditions, the left side is more affected by gait abnormalities than the right one (P < 0.003