For Whom is MAI? A theoretical Perspective on Multilateral Agreements on Investments

Why do we observe some LDCs objecting the prospect of a Multilateral Agreement on Investment (MAI), although they have been keen to liberalize investment in preferential agreements in recent years? In this paper, we analyse the issue of MAI implementation and assess the welfare consequences of such kind of agreements. In our model, participation to MAI involves a trade-off between less rent extraction from multinational firms (MNEs) and more abundant FDI in‡ows. At equilibrium, either all countries enter MAI, or all countries stay out, or only some of them enter. Coordination problems may induce multiple equilibria: the three types of equilibria may coexist. So, the implementation of MAI may depend not only on structural factors but also on the general ”political climate”. When all countries join MAI, world welfare is maximized because this minimizes the hold-up problem faced by MNEs and stimulates investment. However, in an asymmetric world, welfare gains are not guaranteed for all countries.Foreign Direct Investment, International Agreements, Incomplete

A focus on focal surfaces

We make a systematic study of the focal surface of a congruence of lines in the projective space. Using differential techniques together with techniques from intersection theory, we reobtain in particular all the invariants of the focal surface (degree, class, class of its hyperplane section, sectional genus and degrees of the nodal and cuspidal curve). We study in particular the congruences of chords to a smooth curve and the congruences of bitangents or flexes to a smooth surface. We find that they possess unexpected components in their focal surface, and conjecture that they are the only ones with this property.Comment: Plain TeX, 33 pages with no figure

The late accretion and erosion of Vesta's crust recorded by eucrites and diogenites as an astrochemical window into the formation of Jupiter and the early evolution of the Solar System

For decades the limited thickness of Vesta's basaltic crust, revealed by the link between the asteroid and the howardite-eucrite-diogenite family of meteorites, and its survival to collisional erosion offered an important constraint for the study of the early evolution of the Solar System. Some results of the Dawn mission, however, cast doubts on our understanding of Vesta's interior composition and of the characteristics of its basaltic crust, weakening this classical constraint. In this work we investigate the late accretion and erosion experienced by Vesta's crust after its differentiation and recorded in the composition of eucrites and diogenites and show that it offers an astrochemical window into the earliest evolution of the Solar System. In our proof-of-concept case study focusing on the late accretion and erosion of Vesta's crust during the growth and migration of Jupiter, the water enrichment of eucrites appears to be a sensitive function of Jupiter's migration while the enrichment in highly-siderophile elements of diogenites appears to be particularly sensitive to the size-frequency distribution of the planetesimals. The picture depicted by the enrichments created by late accretion in eucrites and diogenites is not qualitatively affected by the uncertainty on the primordial mass of Vesta. Crustal erosion, instead, is more significantly affected by said uncertainty and Vesta's crust survival appears to be mainly useful to study violent collisional scenarios where highly energetic impacts can strip significant amounts of vestan material while limitedly contributing to Vesta's late accretion. Our results suggest that the astrochemical record of the late accretion and erosion of Vesta's crust provided by eucrites and diogenites can be used as a tool to investigate any process or scenario associated to the evolution of primordial Vesta and of the early Solar System.Comment: 21 pages, 15 figures, accepted for publication on Icaru

Habitable Planet Formation in Binary-Planetary Systems

Recent radial velocity observations have indicated that Jovian-type planets can exist in moderately close binary star systems. Numerical simulations of the dynamical stability of terrestrial-class planets in such environments have shown that, in addition to their giant planets, these systems can also harbor Earth-like objects. In this paper, we study the late stage of terrestrial planet formation in such binary-planetary systems, and present the results of the simulations of the formation of Earth-like bodies in their habitable zones. We consider a circumprimary disk of Moon- to Mars-sized objects and numerically integrate the orbits of these bodies at the presence of the Jovian-type planet of the system and for different values of the mass, semimajor axis, and orbital eccentricity of the secondary star. Results indicate that, Earth-like objects, with substantial amounts of water, can form in the habitable zone of the primary star. Simulations also indicate that, by transferring angular momentum from the secondary star to protoplanetary objects, the giant planet of the system plays a key role in the radial mixing of these bodies and the water contents of the final terrestrial planets. We will discuss the results of our simulation and show that the formation of habitable planets in binary-planetary systems is more probable in binaries with moderate to large perihelia.Comment: 27 pages, 11 figures, submitted for publicatio

Bessel beam illumination reduces random and systematic errors in quantitative functional studies using light-sheet microscopy

Light-sheet microscopy (LSM), in combination with intrinsically transparent zebrafish larvae, is a choice method to observe brain function with high frame rates at cellular resolution. Inherently to LSM, however, residual opaque objects cause stripe artifacts, which obscure features of interest and, during functional imaging, modulate fluorescence variations related to neuronal activity. Here, we report how Bessel beams reduce streaking artifacts and produce high-fidelity quantitative data demonstrating a fivefold increase in sensitivity to calcium transients and a 20 fold increase in accuracy in the detection of activity correlations in functional imaging. Furthermore, using principal component analysis, we show that measurements obtained with Bessel beams are clean enough to reveal in one-shot experiments correlations that can not be averaged over trials after stimuli as is the case when studying spontaneous activity. Our results not only demonstrate the contamination of data by systematic and random errors through conventional Gaussian illumination and but,furthermore, quantify the increase in fidelity of such data when using Bessel beams

IMPORTING JOBS AND EXPORTING FIRMS? ON THE WAGE AND EMPLOYMENT IMPLICATIONS OF ITALY’S TRADE AND FOREIGN DIRECT INVESTMENT FLOWS

International economic integration is often blamed for the deteriorating fortunes of unskilled workers in industrial countries. We look at the labor market impact of trade and foreign direct investment in the case of Italy. Our empirical framework allows for trade, technology and factor supply effects. We find that international trade did not contribute to Italy’s labor market problems. Indeed, given that Italy holds quite a distinct pattern of trade specialization, compared to other industrialized countries, international integration as reflected in falling import prices may have boosted the demand for labor there. We also argue that the inability of the Mezzogiorno’s economy to adjust to the changing international environment is one of the main stumbling blocks in Italy’s economy. Finally, we find that greater firm’s mobility may have weakened the power of trade unions and contributed to wage moderation.international trade, foreign direct investment,wages, employment

Optical mapping of neuronal activity during seizures in zebrafish

Mapping neuronal activity during the onset and propagation of epileptic seizures can provide a better understanding of the mechanisms underlying this pathology and improve our approaches to the development of new drugs. Recently, zebrafish has become an important model for studying epilepsy both in basic research and in drug discovery. Here, we employed a transgenic line with pan-neuronal expression of the genetically-encoded calcium indicator GCaMP6s to measure neuronal activity in zebrafish larvae during seizures induced by pentylenetretrazole (PTZ). With this approach, we mapped neuronal activity in different areas of the larval brain, demonstrating the high sensitivity of this method to different levels of alteration, as induced by increasing PTZ concentrations, and the rescuing effect of an anti-epileptic drug. We also present simultaneous measurements of brain and locomotor activity, as well as a high-throughput assay, demonstrating that GCaMP measurements can complement behavioural assays for the detection of subclinical epileptic seizures, thus enabling future investigations on human hypomorphic mutations and more effective drug screening methods. Notably, the methodology described here can be easily applied to the study of many human neuropathologies modelled in zebrafish, allowing a simple and yet detailed investigation of brain activity alterations associated with the pathological phenotype