Optimal Fiscal Policy in a Small Open Economy with Limited Commitment

We introduce limited commitment into a standard optimal fiscal policy model in small open economies. We consider the problem of a benevolent government that signs a risk-sharing contract with the rest of the world, and that has to choose optimally distortionary taxes on labor income, domestic debt and international debt. Both the home country and the rest of the world may have limited commitment, which means that they can leave the contract if they find it convenient. The contract is designed so that, at any point in time, neither party has incentives to exit. We define a small open emerging economy as one where the limited commitment problem is active in equilibrium. Conversely, a small open developed economy is an economy with full commitment. Our model is able to rationalize two stylized facts about fiscal policy in emerging economies: i) the volatility of tax revenues over GDP is higher in emerging economies than in developed ones; ii) the volatility of tax revenues over GDP is positively correlated with sovereign default risk.

Surface wave excitations and backflow effect over dense polymer brushes

Polymer brushes are being increasingly used to tailor surface physicochemistry for diverse applications such as wetting, adhesion of biological objects, implantable devices and much more. Here we perform Dissipative Particle Dynamics simulations to study the behaviour of dense polymer brushes under flow in a slit-pore channel. We discover that the system displays flow inversion at the brush interface for several disconnected ranges of the imposed flow. We associate such phenomenon to collective polymer dynamics: a wave propagating on the brush surface. The relation between the wavelength, the amplitude and the propagation speed of the flow-generated wave is consistent with the solution of the Stokes equations when an imposed traveling wave is assumed as the boundary condition (the famous Taylor's swimmer)

Surface wave excitations and backflow effect over dense polymer brushes

Polymer brushes are increasingly used to tailor surface physicochemistry for various applications such as wetting, adhesion of biological objects, implantable devices, etc. We perform Dissipative Particle Dynamics simulations to study the behavior of dense polymer brushes under flow in a slit-pore channel. We discover that the system displays flow inversion at the brush interface for several disconnected ranges of the imposed flow. We associate such phenomenon to collective polymer dynamics: a wave propagating on the brush surface. The relation between the wavelength, the amplitude and the propagation speed of the flow-generated wave is consistent with the solution of the Stokes equations when an imposed traveling wave is assumed as boundary condition (the famous Taylor's swimmer).Comment: 5 pages, 6 figures, supplemental material (5 pages, 4 figures) attached below the letter and before bibliography, videos available on request to the corresponding author, submitted to SciRe

3He(α,γ)7Be{^3{\rm He}}(\alpha,\gamma){^7{\rm Be}} and 3H(α,γ)7Li{^3{\rm H}}(\alpha,\gamma){^7{\rm Li}} astrophysical SS factors from the no-core shell model with continuum

The ${^3{\rm He}}(\alpha,\gamma){^7{\rm Be}}$ and ${^3{\rm H}}(\alpha,\gamma){^7{\rm Li}}$ astrophysical $S$ factors are calculated within the no-core shell model with continuum using a renormalized chiral nucleon-nucleon interaction. The ${^3{\rm He}}(\alpha,\gamma){^7{\rm Be}}$ astrophysical $S$ factors agree reasonably well with the experimental data while the ${^3{\rm H}}(\alpha,\gamma){^7{\rm Li}}$ ones are overestimated. The seven-nucleon bound and resonance states and the $\alpha+{^3{\rm He}}/{^3{\rm H}}$ elastic scattering are also studied and compared with experiment. The low-lying resonance properties are rather well reproduced by our approach. At low energies, the $s$-wave phase shift, which is non-resonant, is overestimated.Comment: 8 pages, submitted to Phys. Lett.

STRATEGIES AND OUTCOMES OF BIM EDUCATION: ITALIAN EXPERIENCES

The growing need on the part of operators in the construction sector for expertise in digital management of construction information processes has been answered since 2015 in the first level master course called BIM Master, from the Department of Planning Design and Technology of Architecture of Sapienza University of Rome. The training course is now in its fifth edition, registering a growing number of students. It has evolved in terms of content delivery methods, and always provides opportunities for internships in client, designers and construction organizations, achieving significant results in terms of placement. The BIM Master is one of the most consolidated national experiences, and has been proposed since the first edition as a training opportunity that links the needs of the market and the expectations of students. It is configured as a project in continuous development that adapts itself year after year to the evolutionary dynamics of the digital construction market, also resulting from the recent national regulatory innovations (UNI 11337). The complexity of BIM training also increases in relation to the different nature and needs of the operators in the sector: owners; designers; builders; and managers, who lead the need for articulated training courses in relation to the role played in the construction supply chain. This paper critically examines, also on the basis of the results of past editions, the training experience of the BIM Master course of Sapienza University of Rome, analyzing the structure, examining the articulation of the main training modules, assessing the results produced by the students, measuring the critical points and, at the same time, identifying the drivers of greater effectiveness in the transfer of skills of a theme that lends itself to ambiguous interpretations at this history time by operators in the construction industry