Chow groups of weighted hypersurfaces

We extend a result of to Esnault-Levine-Viehweg concerning the Chow groups of hypersurfaces in projective space to those in weighted projective spaces

Saturation Effect and Cyclical Herd Behavior

We analyze a sequential decision model, where in every period a new agent seeks to determine the payoff of some actions. Every agent receives a possibly uninformative signal about the payoffs, and she observes previous choices. Some actions have a saturation effect; i.e., their payoffs become zero if used repeatedly too often albeit the original payoff is recovered later. We show that in every equilibrium and for almost every equilibrium play path, an action will trigger a cyclical herd behavior. We also show that the length of the transition phase between two consecutive herd behavior is at most the time needed to recover from the saturation effect. We thus give an alternative explanation to Kirman (1993) for the cyclicity of herd behavior, based on the negative externality generated by the repeated use of the same action.Herd behavior, Cycles, Saturation effects.

A market microstructure explanation of IPOs underpricing

In a typical IPO game with first-price auctions, we argue that risk-averse investors always underbid in equilibrium because of subjective interpretations of the firm' communication about its actual value and resulting risk aversion about the likelihood of facing investors with higher valuations. We show that the noisier the investors' inferences of the firm' value (in the sense of first-order stochastic dominance) the higher the underbidding level. Our finding is independent of winner's curse effects and possible irrationality, and allows for a testable theory.IPO underpricing; first-price auction; risk aversion; firm' communication

Do Employees’ Sickness Absences React to a Change in Costs for Firms? Evidence from a Natural Experiment

We analyse the impact of a social security reform that changed the costs incurred by firms due to sickness absences. The reform abolished a compulsory insurance for firms, which insured them against the wages paid to sick blue‐collar workers. During the first year after its introduction, we estimate that the reform resulted in about 6.3 percent fewer sickness absences, and in about 8.6 percent fewer absence days. We do not find evidence for changes in hiring or firing, and we find only limited workforce composition changes. We do not find spillover effects on the absences of white‐collar workers. Robustness checks confirm these results

The Failure of the Aetolian Deditio as a Didactic Cultural Clash in the Histories of Polybius (20.9-10)

This paper examines the Aetolian deditio in fidem of 191 as described by Polybius 20.9-10. Erich Gruen influentially interpreted Polybius’ description as inconsistent and exaggerated, on the grounds that Greeks and Romans from the 3rd and 2nd centuries BC had a common understanding of πίστις and fides and that Polybius’ own evidence on deditio was inconsistent. This paper reasserts the older view: that Greeks generally then had a hazy knowledge of Roman culture, including the practice of deditio, and that—even if weight be granted to factors such as the Roman commander’s personal character and ambitions or the historian’s supposed dislike of the Aetolians or his deployment of a degree of dramatic licence or a possible ‘hardening’ in the Romans’ general practice—this passage properly emphasises a genuine cultural clash, thereby promoting Polybius’ fundamental paideia-objective of teaching Greek readers, above all Greek politicians, how to respond competently to the realities of Roman power.Fil: Moreno Leoni, Álvaro Matías. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones y Estudios sobre Cultura y Sociedad. Universidad Nacional de Córdoba. Centro de Investigaciones y Estudios sobre Cultura y Sociedad; Argentin

Psychological Aspects of Market Crashes

This paper analyzes the sensitivity of market crashes to investors'psychology in a standard general equilibrium framwork. Contrary to the traditional view that market crashes are driven by large drops in aggregate endowments, we argue from a theoretical standpoint that individual anticipations of such drops are a necessary condition for crashes to occur, and that the magnitude or such crashes are poritively correlated with the level of individual anticipations of drops

Employability of graduates and development of competencies: mind the gap and mind the step! Empirical evidence for Italy

education; competencies; employability

Symmetry minimizes the principal eigenvalue: an example for the Pucci's sup operator

We explicitly evaluate the principal eigenvalue of the extremal Pucci's sup--operator for a class of special plane domains, and we prove that, for fixed area, the eigenvalue is minimal for the most symmetric set.Comment: 11 pages, 7 figure

Effects of confinement between attractive and repulsive walls on the thermodynamics of an anomalous fluid

We study by molecular dynamics simulations the thermodynamics of an anomalous fluid confined in a slit pore with one wall structured and attractive and another unstructured and repulsive. We find that the phase diagram of the homogeneous part of the confined fluid is shifted to higher temperatures, densities and pressures with respect to the bulk, but it can be rescaled on the bulk case. We calculate a moderate increase of mobility of the homogeneous confined fluid that we interpret as a consequence of the layering due to confinement and the collective modes due to long-range correlations. We show that, as in bulk, the confined fluid has structural, diffusion and density anomalies, that order in the water-like hierarchy, and a liquid-liquid critical point (LLCP). The overall anomalous region moves to higher temperatures, densities and pressure and the LLCP displaces to higher temperature compared to bulk. Motivated by experiments, we calculate also the phase diagram not just for the homogeneous part of the confined fluid but for the entire fluid in the pore and show that it is shifted towards higher pressures but preserves the thermodynamics, including the LLCP. Because our model has water-like properties, we argue that in experiments with supercooled water confined in slit pores with a width of > 3 nm if hydrophilic, and of > 1.5 nm if hydrophobic, the existence of the LLCP could be easier to test than in bulk, where it is not directly accessible