Public investment in basic education and economic growth

The main objective of this paper was to visualize the relation between governmentspending on basic education and the human capital accumulation process, observingthe impacts of this spending on individual investments in higher education, and oneconomic growth. It is used an overlapping-generations model where the governmenttax the adult generation and spent it in basic education of the next generations. Itwas demonstrated that the magnitude of the marginal effect of government spendingin basic education on growth crucially depends on public budget constrains. The paperexplains why some countries with a lot of public investment in basic education growthat low rates. In that sense if a country has only a lot of public investment in basiceducation without investment in higher education it may growth at low rates becausethe taxation can cause distortions in the agents incentives to invest in higher education.

Crime and punishment with habit formation

Moral concepts affect crime supply. This idea is modelled assuming that illegal activities is habit forming. We introduce habits in a intertemporal general equilibrium framework to illegal activities and compare its outcomes with a model without habit formation. The findings are that habit and crime presents a non linear relationship that hinges upon the level of capital and habit formation. It is possible to show that while the effect of habit on crime is negative for low levels o habit formation it becomes positive as habits goes up. Secondly habit reduces the marginal effect of illegal activities return on crime. Finally, the effect of habit on crime depends positively on the amount of capital. This could explain the relationship between size of cities and illegal activity.

Electronic states and transport properties in the Kronig-Penney model with correlated compositional and structural disorder

We study the structure of the electronic states and the transport properties of a Kronig-Penney model with weak compositional and structural disorder. Using a perturbative approach we obtain an analytical expression for the localisation length which is valid for disorder with arbitrary correlations. We show how to generate disorder with self- and cross-correlations and we analyse both the known delocalisation effects of the long-range self-correlations and new effects produced by cross-correlations. We finally discuss how both kinds of correlations alter the transport properties in Kronig-Penney models of finite size.Comment: 23 pages, 5 figure

On the purchasing power parity for latin-american countries

The purpose of this paper is to test the hypothesis of long-run purchasingpower parity (PPP) for all Latin American countries. These countries sharesimilar economic history and contagious effects from currency crises, whichmight lead to comovements in their real exchange rates. New time series unitroot tests found evidence of PPP for the vast majority of countries. In thepanel data framework, tests for the null of unit root, null of stationarity, andunit root under multiple structural breaks indicated stationary real exchangerates. Thus, there is convincing evidence that PPP holds for Latin-Americancountries in the post-1980 period.

Dirac Point and Edge States in a Microwave Realization of Tight-Binding Graphene-like Structures

We present a microwave realization of finite tight-binding graphene-like structures. The structures are realized using discs with a high index of refraction. The discs are placed on a metallic surface while a second surface is adjusted atop the discs, such that the waves coupling the discs in the air are evanescent, leading to the tight-binding behavior. In reflection measurements the Dirac point and a linear increase close to the Dirac point is observed, if the measurement is performed inside the sample. Resonances due to edge states are found close to the Dirac point if the measurements are performed at the zigzag-edge or at the corner in case of a broken benzene ring.Comment: 4 pages, 6 figure

Scanning Fourier Spectroscopy: A microwave analog study to image transmission paths in quantum dots

We use a microwave cavity to investigate the influence of a movable absorbing center on the wave function of an open quantum dot. Our study shows that the absorber acts as a position-selective probe, which may be used to suppress those wave function states that exhibit an enhancement of their probability density near the region where the impurity is located. For an experimental probe of this wave function selection, we develop a technique that we refer to as scanning Fourier spectroscopy, which allows us to identify, and map out, the structure of the classical trajectories that are important for transmission through the cavity.Comment: 4 pages, 5 figure

Perception of categories: from coding efficiency to reaction times

Reaction-times in perceptual tasks are the subject of many experimental and theoretical studies. With the neural decision making process as main focus, most of these works concern discrete (typically binary) choice tasks, implying the identification of the stimulus as an exemplar of a category. Here we address issues specific to the perception of categories (e.g. vowels, familiar faces, ...), making a clear distinction between identifying a category (an element of a discrete set) and estimating a continuous parameter (such as a direction). We exhibit a link between optimal Bayesian decoding and coding efficiency, the latter being measured by the mutual information between the discrete category set and the neural activity. We characterize the properties of the best estimator of the likelihood of the category, when this estimator takes its inputs from a large population of stimulus-specific coding cells. Adopting the diffusion-to-bound approach to model the decisional process, this allows to relate analytically the bias and variance of the diffusion process underlying decision making to macroscopic quantities that are behaviorally measurable. A major consequence is the existence of a quantitative link between reaction times and discrimination accuracy. The resulting analytical expression of mean reaction times during an identification task accounts for empirical facts, both qualitatively (e.g. more time is needed to identify a category from a stimulus at the boundary compared to a stimulus lying within a category), and quantitatively (working on published experimental data on phoneme identification tasks)

Retrospective study of a series of choanal atresia patients

Introduction Although it has been more than 250 years since the first description of choanal atresia (CA), there are still doubts about this abnormality. The differences between unilateral and bilateral forms are seldom discussed. Objectives Aggregate data from patients diagnosed with CA, grouping patients with unilateral and bilateral forms. Methods Retrospective study. Results Eighteen patients were included: 12 (66.6%) presented bilateral atresia, of which 77.8% were mixed bony-membranous type and 22.2% were pure bony type. From the 12 patients with bilateral atresia, 10 presented related malformations, 3 of whom had CHARGE syndrome (coloboma, heart defects, choanal atresia, retardation of growth and development, genitourinary problems, ear abnormalities). From the remaining 6 patients with unilateral atresia, only 2 showed malformations, 1 renal and 1 cardiac. All patients with unilateral atresia needed only 1 surgical procedure, and patients with the bilateral form needed amedian of 2.85 interventions (p ¼ 0.003). The median age of surgical procedure in the unilateral group was 6 years, ranging from 6 months to 18 years, and in the bilateral group was 25 days, ranging from 6 days to 6 years (p ¼ 0.003). The median interval between diagnosis and surgery was 9 months in the unilateral group, ranging from 1 month to 18 years, and in the bilateral group was 1 day, ranging from 1 day to 2 months (p ¼ 0.001). Discussion and Conclusions Success rates with the endoscopic approach vary from 62 to 100%. Nonetheless, most of these reports present results without considering the number of compromised sides. In our opinion, unilateral and bilateral cases involve distinct patients (taking into account the related malformations), have diverging clinical presentations, and show discrepant restenosis rates and therefore could be considered in different groups of analysis