Nonlinear stability of liquid flow down an inclined plan

A modified energy method is proposed to study the nonlinear stability of Poiseuille flow with upper free boundary St, down an inclined plane. Sufficient conditions on Reynolds, and Weber numbers, on the slope of the plane, together with the periodicity along the line of maximum slope are given. All constants are computable. Smallness condition on initial data is required

Structure and Properties of Simple and Aggregate Systems by Circular Dichroism Spectroscopy

This thesis deals with the investigation of structural properties of many different systems via Electronic Circular Dichroism (ECD). The interpretation of experimental data has been carried out mainly with quantum-chemistry methods, such as Density Functional Theory (DFT), on both solution and solid-state systems. The analysis of solution systems is oriented towards applications on biologically active compounds, both natural or synthetic, and its objective is to underline the key role of these approaches in the determination of the absolute configuration and the difficulties that may be encountered in case of flexible molecules. Solid-state measurements represent an attractive alternative to these cases where a lot of conformations are present, but difficulties in the interpretation of the signals due to solid-state interactions which are not observable in solution may be faced. For a better understanding of spectral lineshapes, more detailed analyses have been performed taking into account vibronic effects, which may also assist in the determination of the conformational situation of the investigated substrate. The limitations of the vibronic treatment for coupled electronic states have been considered, leading to a general all-coordinate approach which allows simulating the electronic spectrum of “dimeric” molecules with weakly coupled electronic states through a time dependent approach

Squeezed K^+ K^- correlations in high energy heavy ion collisions

The hot and dense medium formed in high energy heavy ion collisions may modify some hadronic properties. In particular, if hadron masses are shifted in-medium, it was demonstrated that this could lead to back-to-back squeezed correlations (BBC) of particle-antiparticle pairs. Although well-established theoretically, the squeezed correlations have not yet been discovered experimentally. A method has been suggested for the empirical search of this effect, which was previously illustrated for phi-phi pairs. We apply here the formalism and the suggested method to the case of K^+ K^- pairs, since they may be easier to identify experimentally. The time distribution of the emission process plays a crucial role in the survival of the BBC's. We analyze the cases where the emission is supposed to occur suddenly or via a Lorentzian distribution, and compare with the case of a Levy distribution in time. Effects of squeezing on the correlation function of identical particles are also analyzed.Comment: 9 pages and 6 figures (figures 2 to 6 contain 4 plots each). Paragraph added to text, figures 2 to 6 revised for improving visualizatio

HBT Interferometry: Historical Perspective

I review the history of HBT interferometry, since its discovery in the mid 1950's, up to the recent developments and results from BNL/RHIC experiments. I focus the discussion on the contributions to the subject given by members of our Brazilian group.Comment: 32 pages, 42 figures; corrected typos, replaced corrupted figure

Excess Smoothness and Durable Goods: Evidence from Subjective Expectations Data

This paper derives and estimates a model where durable and non-durable consumption are allowed to be non-separable in utility and individuals face a convex adjustment cost whenever they want to purchase a new durable good. Subjective expectations data allow to identify and estimate the marginal propensity to consume out of permanent shocks, which is a key parameter for the understanding of the excess smoothness puzzle and for policy purposes.Durable Goods, Intertemporal Substitution, Excess Smoothness, Subjective Expectations

Households’ saving and debt in Italy

We review savings trends in Italy, summarizing available empirical evidence on Italians’ motives to save, relying on macroeconomic indicators as well as on data drawn from the Bank of Italy’s Survey of Household Income and Wealth from 1984 to 2004. The macroeconomic data indicate that households’ saving has dropped significantly, although Italy continues to rank above most other countries in terms of saving. We then examine with microeconomic data four indicators of household financial conditions: the propensity to save, the proportion of households with negative savings, the proportion of households with debt, and the proportion of households that lack access to formal credit markets. By international comparison, the level of debt of Italian households and default risk are relatively low. But in light of the deep changes undergone by the Italian pension system, the fall in saving is a concern, particularly for individuals who entered the labor market after the 1995 reform and who have experienced the largest decline in pension wealth. JEL Classification: D9

Squeezed correlations of strange particle-antiparticles

Squeezed correlations of hadron-antihadron pairs are predicted to appear if their masses are modified in the hot and dense medium formed in high energy heavy ion collisions. If discovered experimentally, they would be an unequivocal evidence of in-medium mass shift found by means of hadronic probes. We discuss a method proposed to search for this novel type of correlation, illustrating it by means of D_s-mesons with in-medium shifted masses. These particles are expected to be more easily detected and identified in future upgrades at RHIC.Comment: 6 pages, 3 figures with parts a) and b), SQM 2009 contribution; added acknowledgmen

Investment in financial literacy, social security and portfolio choice : [version may 21, 2013]

We present an intertemporal portfolio choice model where individuals invest in financial literacy, save, allocate their wealth between a safe and a risky asset, and receive a pension when they retire. Financial literacy affects the excess return and the cost of stock market participation. Since literacy depreciates over time and has a cost related to current consumption, investors simultaneously choose how much to save, the portfolio allocation, and the optimal investment in literacy. This last depends on households' resources, its preference parameters and on how much financial literacy affects the returns on risky assets and the stock market participation cost, and the returns on social security wealth. The model implies one should observe a positive correlation between stock market participation (and risky asset share, conditional on participation) and financial literacy, and a negative correlation between the generosity of the social security system and financial literacy. The model also implies that the stock of financial literacy accumulated early in life is positively correlated with the individual's wealth and portfolio allocations later in life. Using microeconomic cross-country data, we find support for these predictions

Investment in financial literacy and saving decisions

We present an intertemporal consumption model of consumer investment in financial literacy. Consumers benefit from such investment because their stock of financial literacy allows them to increase the returns on their wealth. Since literacy depreciates over time and has a cost in terms of current consumption, the model determines an optimal investment in literacy. The model shows that financial literacy and wealth are determined jointly, and are positively correlated over the life cycle. Empirically, the model leads to an instrumental variables approach, in which the initial stock of financial literacy (as measured by math performance in school) is used as an instrument for the current stock of literacy. Using microeconomic and aggregate data, we find a strong effect of financial literacy on wealth accumulation and national saving, and also show that ordinary least squares estimates underestate the impact of financial literacy on saving. JEL Classification: E2, D8, G1, J24 Keywords: Financial Literacy, Cognitive Abilities, Human Capital, Savin