Do Workers' Remittances Reduce the Probability of Current Account Reversals?

The paper combines the literature on financial crises in emerging markets and developing economies with that on international migrations by investigating whether the increasingly large flows of workers' remittances can help reduce the probability of current account reversals. The rationale for this stands in the great stability and low cyclicality of remittances as compared to other private capital flows: these properties, combined with the fact that remittances are cheap inflows of foreign currencies, might reduce the probability that foreign investors suddenly flee out of emerging markets and developing economies and trigger a dramatic current account adjustment. We find that remittances can indeed have such a beneficial effect. In particular, we show that a high level of remittances, as a ratio of GDP, makes the relationship between a decreasing stock of international reserves (over GDP) and a higher probability of current account crises less stringent. The same occurs, though less neatly, for the positive relationship between an increasing stock of external debt (over GDP) and the probability of current account reversals. Our results point also to a threshold effect of remittances: the mechanisms just described are, in fact, much stronger when remittances are above 3 percent of GDP.current account reversals, workers remittances, international reserves, external debt

Distributed Bragg reflectors for the colorimetric detection of bacterial contaminants and pollutants for food quality control

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Design of 1D photonic crystals for colorimetric and ratiometric refractive index sensing

Abstract Photonic crystals can be employed effectively as simple and low-cost colorimetric sensors for monitoring variation in the environmental refractive index. In most cases, the photonic colorimetric approach relies on the use of porous and permeable materials to highlight refractive index (RI) modulation, although a fine control over the size distribution and free volume can be complex to achieve. Here, we propose nonporous low-layer count distributed Bragg reflectors (DBRs) as simple optical devices for colorimetric refractive index sensing. In our feasibility study, we simulated the reflectance of DBRs consisting of two to five SiO2/TiO2 bilayers upon variation of the external refractive index. We found that the 2-bilayers sample exhibits the highest sensitivity to RI variations, and identified the ratio between the first and third order reflectance intensity as simple yet efficient ratiometric parameter to discern analytes with different refractive indices. This approach can provide a promising perspective for the development of cheap and portable devices for environmental detection of a wide range of substances

Anisotropic complex refractive indices of atomically thin materials: determination of the optical constants of few-layer black phosphorus

In this work we briefly review the studies of the optical constants of monolayer transition metal dichalcogenides and few layer black phosphorus, with particular emphasis to the complex dielectric function and refractive index. Specifically, we give an estimate of the complex index of refraction of phosphorene and few-layer black phosphorus. We extracted the complex index of refraction of this material from differential reflectance data reported in literature by employing a constrained Kramers-Kronig analysis. Finally, we studied the linear optical response of multilayer systems embedding phosphorene by using the transfer matrix method.Comment: 11 pages, 3 figure

The physics of plasma membrane photostimulation

Cell membrane perturbation is a common way to stimulate cells by using external actuators. Recently, nanotechnology has added a number of new strategies for doing this, enlarging the scope and the range of mechanisms involved. Here, we describe a number of possible perturbation actions that are driven by light, and we try to capture the underlying phenomena. The discussion is based on the simple equivalent circuit model for the cell membrane

Electrochromism in Electrolyte-Free and Solution Processed Bragg Stacks

Achieving an active manipulation of colours has huge implications in optoelectronics, as colours engineering can be exploited in a number of applications, ranging from display to lightning. In the last decade, the synergy of the highly pure colours of 1D photonic crystals, also known as Bragg stacks, with electro-tunable materials have been proposed as an interesting route to attain such a technologically relevant effect. However, recent works rely on the use of liquid electrolytes, which can pose issues in terms of chemical and environmental stability. Here, we report on the proof-of-concept of an electrolyte free and solution-processed electrochromic Bragg stack. We integrate an electro-responsive plasmonic metal oxide, namely indium tin oxide, in a 1D photonic crystal structure made of alternating layers of ITO and TiO2 nanoparticles. In such a device we observed 15 nm blue-shift upon application of an external bias (5 V), an effect that we attribute to the increase of ITO charge density arising from the capacitive charging at the metal oxide/dielectric interface and from the current flowing throughout the porous structure. Our data suggest that electrochromism can be attained in all-solid state systems by combining a judicious selection of the constituent materials with device architecture optimisation

The side effects of national financial sector policies: framing the debate on financial protectionism

The decrease of financial integration both at the global and European level reflects, to a certain extent, a market response to the crisis. It might, however, also be partly driven by policies such as capital flow management measures (CFMs). In addition, several other measures taken by central banks, regulators and governments in response to the crisis may have had less obvious negative side effects on financial integration. Against this backdrop, this paper explores broad definitions of financial protectionism in order to raise awareness of the fact that the range of policies which could negatively affect financial integration may be much wider than residency-based CFMs. At the same time, the paper acknowledges that these measures have mostly been taken for legitimate financial stability purposes and with no protectionist intentions. The paper considers five categories of policy measures which could contribute to financial fragmentation both at the global and at the EU level: currency-based measures directed towards banks, geographic ring fencing, some financial repression policies, crisis resolution policies with a national bias, and some financial sector taxes

Synthesis of Bioctacene‐Incorporated Nanographene with Near‐Infrared Chiroptical Properties

We report the synthesis of a hexabenzoperihexacene (HBPH) with two incorporated octacene substructures, which was unambiguously characterized by single-crystal X-ray analysis. The theoretical isomerization barrier of the (P,P)-/(P,M)-forms was estimated to be 38.4 kcal mol−1, and resolution was achieved by chiral HPLC. Notably, the enantiomers exhibited opposite circular dichroism responses up to the near-infrared (NIR) region (830 nm) with a high gabs value of 0.017 at 616 nm. Moreover, HBPH demonstrated NIR emission with a maximum at 798 nm and an absolute PLQY of 41 %. The excited-state photophysical properties of HBPH were investigated by ultrafast transient absorption spectroscopy, revealing an intriguing feature that was attributed to the rotational and/or conformational dynamics of HBPH after excitation. These results provide new insight into the design of chiral nanographene with NIR optical properties for potential chiroptical applications.journal articl