The Frisch Elasticity in the Mercosur Countries: A Pseudo-Panel Approach

This paper provides estimates for the Mercosur countries of the Frisch elasticity – i.e., the elasticity of substitution between worked hours and real wages holding constant the marginal utility of wealth. We find a strong heterogeneity, with estimated elasticities ranging from 12.8 in Argentina to -13.1 in Paraguay. Brazil and Uruguay are in between, both with negative values of -1.9 and -1.4, respectively. We argue that the existence of severe liquidity constraints is the main reason behind the negative estimates found in Brazil, Paraguay and Uruguay. The heterogeneity of these estimates is the outcome of differences in many relevant economic dimensions – ranging from sectorial specialization to welfare state provisions and labor market specificities – all of them crucially affecting the socioeconomic situation of individuals. The diversity of Frisch elasticities calls for the development of a cross-country (rather than a within-country) policy approach, since they crucially affect the dynamics of the business cycle and business cycle synchronization is a step prior to the design of macro-convergence policies in the Mercosur context.Frisch elasticity, labor supply, liquidity constraints, Mercosur, life-cycle models, pseudo-panel (synthetic panel)

Estimating hyperbolicity of chaotic bidimensional maps

We apply to bidimensional chaotic maps the numerical method proposed by Ginelli et al. to approximate the associated Oseledets splitting, i.e. the set of linear subspaces spanned by the so called covariant Lyapunov vectors (CLV) and corresponding to the Lyapunov spectrum. These subspaces are the analog of linearized invariant manifolds for non-periodic points, so the angles between them can be used to quantify the degree of hyperbolicity of generic orbits; however, being such splitting non invariant under smooth transformations of phase space, it is interesting to investigate the properties of transversality when coordinates change, e.g. to study it in distinct dynamical systems. To illustrate this issue on the Chirikov-Taylor standard map we compare the probability densities of transversality for two different coordinate systems; these are connected by a linear transformation that deforms splitting angles through phase space, changing also the probability density of almost-zero angles although complete tangencies are in fact invariant. This is completely due to the PDF transformation law and strongly suggests that any statistical inference from such distributions must be generally taken with care.Comment: 14 pages, 23 figures (This paper is for the IJBC Special Issue edited by Prof. Gregoire Nicolis, Prof. Marko Robnik, Dr. Vassilis Rothos and Dr. Haris Skokos

Correlation decay and large deviations for mixed systems

We consider low--dimensional dynamical systems with a mixed phase space and discuss the typical appearance of slow, polynomial decay of correlations: in particular we emphasize how this mixing rate is related to large deviations properties.Comment: 6 pages, 2 figures, submitted to publicatio

Transition metal catalyzed cyclizations and C-H couplings of heterocyclic scaffolds

This thesis work is consecrated to the study of transition metal-catalyzed C-H activation processes for the synthesis or the functionalization of heterocycles. First, a new example of divergent catalysis was developed, which involves the employment of palladium tetrakis complex for the hydroamination or Pt(II) salts for the C-H hydroarylation reaction of O-propargyloxy anilines. The resulting benzopyranes are lately employed through a three steps efficient synthesis for the preparation of pyrano[3,2-h]quinolins. A new efficient version of Ru(0)-catalyzed carbonylative Murai reaction for the C3-H acylation was investigated using bidentate or aromatic imines as directing group. The coupling with vinylsilanes or styrenes was extended to a series of pentatomic heterocycles with moderate or excellent yields and the reaxtion mechanism was clarified by DFT calculation. Lastly, a totally new oxidant-free version of Ru(0)-catalyzed Fujiwara-Moritani reaction was studied. The trimeric complex of Ru3(CO)12 was employed for the C3-alkenylation with acrylates or electronpoor olefins with moderate or excellent yields. The reaction mechanism seems to proceed, after the activation step and the olefin insertion, through a \uf062-elimination step followed by a reductive elimination of the metal species formed.Ce travail de th\ue8se est consacr\ue9 \ue0 l'\ue9tude des processus d'activation C-H catalys\ue9s par les m\ue9taux de transition pour la synth\ue8se ou la fonctionnalisation d'h\ue9t\ue9rocycles. Tout d'abord, un nouvel exemple de catalyse divergente a \ue9t\ue9 d\ue9velopp\ue9, qui implique l'utilisation du complexe t\ue9trakis de palladium pour l'hydroamination ou des sels de Pt(II) pour la r\ue9action d'hydroarylation C-H des O-propargyloxy anilines. Les benzopyranes r\ue9sultants sont r\ue9cemment employ\ue9s \ue0 travers une synth\ue8se efficace en trois \ue9tapes pour la pr\ue9paration de pyrano [3,2-h] quinolines.Une nouvelle version efficace de la r\ue9action carbonylative de Murai catalys\ue9e par Ru(0) pour l'acylation C3-H a \ue9t\ue9 \ue9tudi\ue9e en utilisant des imines bident\ue9es ou aromatiques comme groupe directeur. Le couplage avec des vinylsilanes ou des styr\ue8nes a \ue9t\ue9 \ue9tendu \ue0 une s\ue9rie d'h\ue9t\ue9rocycles pentatomiques avec des rendements mod\ue9r\ue9s ou excellents et le m\ue9canisme de r\ue9extion a \ue9t\ue9 clarifi\ue9 par calcul DFT.Enfin, une toute nouvelle version sans oxydant de la r\ue9action Fujiwara-Moritani catalys\ue9e par Ru(0) a \ue9t\ue9 \ue9tudi\ue9e. Le complexe trim\ue9rique de Ru3(CO)12a \ue9t\ue9 utilis\ue9 pour l'alc\ue9nylation en C3 avec des acrylates ou des ol\ue9fines pauvres en \ue9lectrons avec des rendements mod\ue9r\ue9s ou excellents. Le m\ue9canisme de r\ue9action semble se d\ue9rouler, apr\ue8s l'\ue9tape d'activation et l'insertion d'ol\ue9fine, par une \ue9tape de \uf062-\ue9limination suivie d'une \ue9limination r\ue9ductrice de l'esp\ue8ce m\ue9tallique form\ue9e

Compressive Sensing for Dynamic XRF Scanning

X-Ray Fluorescence (XRF) scanning is a widespread technique of high importance and impact since it provides chemical composition maps crucial for several scientific investigations. There are continuous requirements for larger, faster and highly resolved acquisitions in order to study complex structures. Among the scientific applications that benefit from it, some of them, such as wide scale brain imaging, are prohibitively difficult due to time constraints. However, typically the overall XRF imaging performance is improving through technological progress on XRF detectors and X-ray sources. This paper suggests an additional approach where XRF scanning is performed in a sparse way by skipping specific points or by varying dynamically acquisition time or other scan settings in a conditional manner. This paves the way for Compressive Sensing in XRF scans where data are acquired in a reduced manner allowing for challenging experiments, currently not feasible with the traditional scanning strategies. A series of different compressive sensing strategies for dynamic scans are presented here. A proof of principle experiment was performed at the TwinMic beamline of Elettra synchrotron. The outcome demonstrates the potential of Compressive Sensing for dynamic scans, suggesting its use in challenging scientific experiments while proposing a technical solution for beamline acquisition software.Comment: 16 pages, 7 figures, 1 tabl

Wave-Shaped Round Functions and Primitive Groups

Round functions used as building blocks for iterated block ciphers, both in the case of Substitution-Permutation Networks and Feistel Networks, are often obtained as the composition of different layers which provide confusion and diffusion, and key additions. The bijectivity of any encryption function, crucial in order to make the decryption possible, is guaranteed by the use of invertible layers or by the Feistel structure. In this work a new family of ciphers, called wave ciphers, is introduced. In wave ciphers, round functions feature wave functions, which are vectorial Boolean functions obtained as the composition of non-invertible layers, where the confusion layer enlarges the message which returns to its original size after the diffusion layer is applied. This is motivated by the fact that relaxing the requirement that all the layers are invertible allows to consider more functions which are optimal with regard to non-linearity. In particular it allows to consider injective APN S-boxes. In order to guarantee efficient decryption we propose to use wave functions in Feistel Networks. With regard to security, the immunity from some group-theoretical attacks is investigated. In particular, it is shown how to avoid that the group generated by the round functions acts imprimitively, which represent a serious flaw for the cipher

What memory binding functions is the hippocampus responsible for?

The role of the hippocampus in binding information in working memory (WM) is little understood. When complex experiences comprise associations between different pieces of information such as objects and locations (relational binding), the function of the hippocampus is required to hold them in WM (Mitchell et al., 2000; 2006; Piekema, 2006). However, recent evidence suggests that if the to-be-associated information leads to the formation of integrated objects such as coloured shapes (conjunctive binding), the hippocampus is less involved in holding temporary representations of these complex events in WM (Baddeley et al., 2010; Piekema, 2006). We investigated the relational and conjunctive binding hypotheses of the hippocampal functions in a patient with right hippocampal damage. The patient and controls were asked to study visual arrays of stimuli which consisted of shape-colour relations (shape-colour pairs) or shape-colour conjunctions (coloured shapes). After the study array, they were presented with a new screen consisting of one set of shapes (line drawings) and one set of colours. They were asked to reconstruct the bindings by selecting the shapes and their corresponding colours. As compared to healthy controls, the patient was impaired in holding relations of shapes and colours in WM whereas he could retain the conjunctions similarly to controls. These results lend support to the role of the hippocampus in supporting memory for inter-item associations but not memory for conjunctions of features which define objects' identity