Non-hyperbolic boundary equilibrium bifurcations in planar Filippov systems: a case study approach

Boundary equilibrium bifurcations in piecewise smooth discontinuous systems are characterized by the collision of an equilibrium point with the discontinuity surface. Generically, these bifurcations are of codimension one, but there are scenarios where the phenomenon can be of higher codimension. Here, the possible collision of a non-hyperbolic equilibrium with the boundary in a two-parameter framework and the nonlinear phenomena associated with such collision are considered. By dealing with planar discontinuous (Filippov) systems, some of such phenomena are pointed out through specific representative cases. A methodology for obtaining the corresponding bi-parametric bifurcation sets is developed.

The Benefits of building barrier-free: a contingent valuation of accessibilty as an attribute of housing

Estimating the social benefits of barrier-free building has always required indirect solutions, such as calculating the savings in social services, hospitalisation or adaptations made possible by the increase in accessibility. This research uses the Contingent Valuation Method to gain a direct appraisal of the benefits from barrier-free housing. When comparing two similar dwellings, with the only difference being their accessibility conditions, the 1,007 randomly chosen households that answered the direct survey would pay, on average 12.5 per cent more for being barrier-free. None of the different appraisals made on accessibility costs reaches 5 per cent. This confirms the social profitability of building without barriers and shows the potential size of the private market for those housing developers that meet the demand. Accessibility is a general concern, an economic good or attribute that most households value, irrespective of the physical conditions of their members.

La influència del dolor i els factors relacionats amb el dolor sobre el nivell de funcionament dels joves entre 8 i 16 anys d'edat

Projecte de recerca elaborat a partir d’una estada al Pain Management Unit de la University of Bath-Royal National Hospital for Rheumatic Disease, a Gran Bretanya, entre juliol i octubre del 2006. El dolor i la discapacitat que hi va associada són experiències comunes. Les relacions entre variables de tipus biològic, social i psicològic han estat rarament investigades en mostres de nens que informen de dolor però extrets de contextos no clínics. L’objectiu d'aquest estudi va ser identificar els predictors de funcionament ens nens escolaritzats, que informaven que el dolor era una experiència força freqüent. Mig miler de nens d'entre 8 i 16 anys i els seus pares van participar en aquest estudi de disseny transversal. Informació de tipus biològic, social i psicològic era recollida a través d'entrevistes individualitzades amb els nens i la complementació de qüestionaris auto-informats per pares. El nivell funcionament del nen va ser avaluat a partir de 4 indicadors: auto-informes de qualitat de vida, assistència a l'escola, implicació en activitats físiques i/o esportives fòra de l'escola, i implicació en activitats de tipus sedentari. Es van recollir diversos tipus de variables psicològiques referents a l’afrontament del nen davant del dolor i tipus d'atenció dels pares a les conductes de dolor dels seu fill. Els resultats mostren un patró variable en funció de la mesura de funcionament específica utilitzada. Més específicament, s'ha proposat que la resposta de por a les experiències de dolor diàries pot ser un important predictor de funcionament. Són necessaris més estudis sobre la relació entre dolor i nivell d'implicació en conductes actives o sedentàries en nens.

On the boundedness on inhomogeneous Lipschitz spaces of fractional integrals, singular integrals and hypersingular integrals associated to non-doubling measures on metric spaces

In this paper we prove T1 type necessary and sufficient conditions for the boundedness on inhomogeneous Lipschitz spaces of fractional integrals and singular integrals defined on a measure metric space whose measure satisfies a n-dimensional growth. We also show that hypersingular integrals are bounded on these spaces.

Study of the influence of grain size and precipitates on the electromagnetic losses in different grades of non-oriented fully processed electrical steel

The study was performed in the installations of OCAS, a Steel Research Centre of ArcelorMittal. Taking M32 steel (3.25%Si+0.9%Al) as the basis chemical composition and three different thicknesses (0.35, 0.5 and 0.65mm), different annealing conditions (temperature and time) have been applied in the laboratory simulator at St. Chély, France. The aim was to link annealing parameters, grain size and energy loss. It was determined the optimum annealing parameters to reach the lowest power losses for three different grades of non-oriented fully processed electrical steel. In addition, M250-50 samples having different magnetic behaviour (high and low losses) but the same grain size and texture, have been analyzed in terms of TEM observations of their precipitates, in the University of Marseille. The results reveal that a high amount of medium and big precipitates (&10 nm) worsen the magnetic properties of the material. The small precipitates (&10nm) do not have a strong influence on the magnetic properties. The presence of precipitates can have a great influence on the power losses and further work is clearly necessary.

Link between microstructure and properties in new metallurgical concepts for very low loss non-oriented electrical steel

The influence of chemistry and soaking temperature (maximal temperature of the continuous annealing) on the final properties of non-oriented electrical steels has been studied. With this objective two different studies have been performed. First the Mn, Ni and Cr content of a low loss electrical steel composition has been modified. An intermediate content and a high content of each element has been added in order to study the influence of this components on the magnetic looses, grain size and texture. Secondly the influence of the soaking temperature on magnetic properties, grain size and oxidation in four grades of non-oriented electrical steels (Steel A, B, C and D) was studied.

Quasiconformal maps, analytic capacity, and non linear potentials

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The non-linear Dirichlet problem in Hadamard manifolds

We prove existence theorems for the Dirichlet problem for hypersurfaces of constant special Lagrangian curvature in Hadamard manifolds. The first results are obtained using the continuity method and approximation and then refined using two iterations of the Perron method. The a-priori estimates used in the continuity method are valid in any ambient manifold.

An Introduction to parametric and non-parametric models for bivariate positive insurance claim severity distributions

We present a real data set of claims amounts where costs related to damage are recorded separately from those related to medical expenses. Only claims with positive costs are considered here. Two approaches to density estimation are presented: a classical parametric and a semi-parametric method, based on transformation kernel density estimation. We explore the data set with standard univariate methods. We also propose ways to select the bandwidth and transformation parameters in the univariate case based on Bayesian methods. We indicate how to compare the results of alternative methods both looking at the shape of the overall density domain and exploring the density estimates in the right tail.

Stable stationary states of non-local interaction equations

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Gaussian estimates for the density of the non-linear stochastic heat equation in any space dimension

In this paper, we establish lower and upper Gaussian bounds for the probability density of the mild solution to the stochastic heat equation with multiplicative noise and in any space dimension. The driving perturbation is a Gaussian noise which is white in time with some spatially homogeneous covariance. These estimates are obtained using tools of the Malliavin calculus. The most challenging part is the lower bound, which is obtained by adapting a general method developed by Kohatsu-Higa to the underlying spatially homogeneous Gaussian setting. Both lower and upper estimates have the same form: a Gaussian density with a variance which is equal to that of the mild solution of the corresponding linear equation with additive noise.

CO2 emissions and economic activity: heterogeneity across countries and non stationary series

This paper explores the homogeneity of the functional form, the parameters, and the turning point, when appropriate, of the relationship between CO2 emissions and economic activity for 31 countries (28 OECD, Brazil, China, and India) during the period 1950 to 2006 using cointegration analysis. With a sample highly overlapped over time between countries, the result reveals that the homogeneity across countries is rejected, both in functional form and in the parameters of long term relationship. This confirms the relevance of considering the heterogeneity in exploring the relationship between air pollution and economic activity to avoid spurious parameter estimates and infer a wrong behavior of the functional form, which could lead to induce that the relationship is reversed when in fact it is direct.

A correlation sensitivity analysis of non-life underwriting risk in solvency capital requirement estimation

This paper analyses the impact of using different correlation assumptions between lines of business when estimating the risk-based capital reserve, the Solvency Capital Requirement (SCR), under Solvency II regulations. A case study is presented and the SCR is calculated according to the Standard Model approach. Alternatively, the requirement is then calculated using an Internal Model based on a Monte Carlo simulation of the net underwriting result at a one-year horizon, with copulas being used to model the dependence between lines of business. To address the impact of these model assumptions on the SCR we conduct a sensitivity analysis. We examine changes in the correlation matrix between lines of business and address the choice of copulas. Drawing on aggregate historical data from the Spanish non-life insurance market between 2000 and 2009, we conclude that modifications of the correlation and dependence assumptions have a significant impact on SCR estimation.

A non-possibility theorem for joint-stability in interindustry models

Joint-stability in interindustry models relates to the mutual simultaneous consistency of the demand-driven and supply-driven models of Leontief and Ghosh, respectively. Previous work has claimed joint-stability to be an acceptable assumption from the empirical viewpoint, provided only small changes in exogenous variables are considered. We show in this note, however, that the issue has deeper theoretical roots and offer an analytical demonstration that shows the impossibility of consistency between demand-driven and supply-driven models.

The non-absoluteness of model existence in uncountable cardinals for Lw1,w

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