Testing for hysteresis in unemployment in OECD countries. New evidence using stationarity panel tests with breaks†

This paper tests hysteresis effects in unemployment using panel data for 19 OECD countries covering the period 1956-2001. The tests exploit the cross-section variations of the series, and additionally, allow for a different number of endogenous breakpoints in the unemployment series. The critical values are simulated based on our specific panel sizes and time periods. The findings stress the importance of accounting for exogenous shocks in the series and give support to the natural-rate hypothesis of unemployment for the majority of the countries analyzed.

Global imbalances and the intertemporal external budget constraint: A multicointegration approach

This paper analyzes the external solvency of a group of 23 OECD countries for the period 1970–2012. The empirical strategy adopted underlines the increasing importance of the financial channel for the external adjustment as proposed in Gourinchas and Rey (2007). We unify the traditional approaches to testing for external sustainability considering the stock-flow system created by the variables representing the external relationships of an open economy. External sustainability is tested using several types of cointegration and multicointegration tests. The results obtained point to weak sustainability in the flows analysis, whereas some degree of strong sustainability is found for up to six countries in the stock-flow approach. Among these countries we find both non-European economies, such as Japan and New Zealand, and Euro-area members, especially those with more restricted access to financing in the international markets

Testing for external sustainability under a monetary integration process. Does the Lawson doctrine apply to Europe?

Monetary integration, and more specifically, the creation of a monetary union in Europe, raises new economic questions concerning its functioning and governance. In particular, we focus on the implications of high and persistent current account deficits for the economic performance of monetary union members in the medium term. Recent literature has argued that conventional measures of external sustainability are misleading because they omit the effects of capital variations on net foreign asset positions due to, among others, stock or debt market crises. In this paper we revisit external sustainability making use of the database developed by Lane and Milesi-Ferretti (2007) that includes these “valuation effects”. The sample period studied covers from the launching of the monetary integration process in Europe (the creation of the European Snake in 1972) up to 2011. Our econometric methodology accounts for the increasing cross-section dependence among EMU countries as well as for possible structural breaks endogenously determined. The results point to the need of abrupt adjustments, either led by the markets or promoted by pro-active policy measures, in order to offset external disequilibria. These results would give support to the surveillance measures proposed by the European Commission (2009, 2010a) and would reject the Lawson's doctrine of “laissez-faire”.M. Camarero and C. Tamarit, and J.L. Carrion-i-Silvestre gratefully acknowledge the financial support from the MICINN CICYT co-ordinated projects CICYT ECO2011-30260-C03-01 and 03 respectively. Cecilio Tamarit and Mariam Camarero are also members of the Research Group of Excellence on Economic Integration INTECO, funded by Generalitat Valenciana Prometeo action 2009/098. This paper has been developed within the research network SOLVEX, (ECO2009-06676-E/ECON) funded by MICINN

The relationship between debt level and fiscal sustainability in OECD countries

In this article we unify the traditional approaches to testing for fiscal sustainability considering the stock-flow system that fiscal variables configure. Our approach encompasses previous ways of testing for sustainability. The results obtained for a group of 17 Organization for Economic Cooperation and Development -OECD- countries point to weak fiscal sustainability, as well as to the existence of cointegration between deficit and debt, confirming the relevance of the stock-flow approach. Allowing for structural breaks and multicointegration turns out to be of critical importance to assess whether the fiscal authorities apply their policies looking for sustainability and whether, simultaneously, they try to stabilize real debt target levels

Reversible barocaloric effects over a large temperature span in fullerite C60

Solid-state cooling methods based on field-driven first-order phase transitions are often limited by significant hysteresis and small temperature span, which increase the input work required to drive the cooling cycle reversibly and reduce the temperature range of operation. Here we show that giant reversible caloric effects can be driven using low hydrostatic pressures in the molecular crystal of fullerene C60 across its order-disorder first-order phase transition due to a small transition hysteresis and a high sensitivity of the transition to pressure. In particular, we obtain isothermal entropy changes ΔS = 25 J K−1 kg−1 under reversible application and removal of a pressure as low as p = 0.05 GPa. We also demonstrate that these features allow us to obtain these giant effects in a wide temperature span around room temperature which, furthermore, is desirable for single-component regenerative coolers. For a pressure change of p = 0.41 GPa, we obtain giant reversible values of ΔS = 31 J K−1 kg−1 and ΔT = 11 K, in a temperature interval larger than 50 K. This very good barocaloric performance postulates C60 as one of the best candidates known so far to be considered by engineers for the development of barocaloric devices. The physics underlying these caloric effects is also analyzed

Análisis de la sostenibilidad del sector exterior en la OCDE con técnicas de multicointegración

Este artículo analiza la sostenibilidad externa de un grupo de 23 países de la OCDE durante el periodo 1970-2020. La estrategia empírica adoptada muestra la importancia del desequilibrio acumulado como desencadenante del ajuste externo, en línea con la propuesta de Gourinchas y Rey (2007). Para ello, contrastamos la sostenibilidad externa a través de la relación acumulado-flujo entre las variables que representan las relaciones externas de una economía abierta utilizando varios tipos de contrastes de cointegración y multicointegración. Los resultados obtenidos apuntan hacia la sostenibilidad en sentido débil en el análisis de los flujos, mientras que desde el punto de vista del enfoque acumulado-flujo se concluye que cuatro países mostrarían sostenibilidad durante parte del periodo investigado tras realizar ajustes. Entre estos países se encuentran tanto economías tradicionalmente acreedoras, como Nueva Zelanda y Suiza, como deudoras (de la zona euro), en concreto, España y Portugal, que tuvieron acceso más restringido a la financiación en los mercados internacionales durante la última crisis financiera

Reversible and irreversible colossal barocaloric effects in plastic crystals

The extremely large latent heat exchanged in phase transitions involving strong molecular orientational disordering has recently led to the proposal of plastic crystals as a feasible solution for solid-state barocaloric eco-friendly cooling technologies. Here we determine the reversible barocaloric response of four plastic crystals derived from neopentane [C(CH3)4]: (NH2)C(CH2OH)3 (TRIS for short), (NH2)(CH3)C(CH2OH)2 (AMP), (CH3)C(CH2OH)3 (PG) and (CH3)3C(CH2OH) (NPA). All of them display colossal entropy changes at their ordered-plastic phase transition, which is a primal requirement for competitive barocaloric materials. However, we show that it is also important to verify that the large barocaloric effects can be achieved using pressures that, while being moderate, are large enough to overcome the pressure-dependent hysteresis. From this quantity and using the quasi-direct method, we determine the minimum pressure needed to achieve reversible barocaloric effects, prev, for each compound. Specifically, we find a small and moderate prev for PG and NPA, respectively, which therefore display colossal reversible barocaloric effects comparable to harmful fluids used in current refrigerators and thus confirm the potential of plastic crystals as excellent alternatives. Instead, in TRIS and AMP, the obtained prev is excessive to yield reversible barocaloric effects useful for cyclic applications

Drug-Biopolymer Dispersions: Morphology- and Temperature- Dependent (Anti)Plasticizer Effect of the Drug and Component-Specific Johari–Goldstein Relaxations

Amorphous molecule-macromolecule mixtures are ubiquitous in polymer technology and are one of the most studied routes for the development of amorphous drug formulations. For these applications it is crucial to understand how the preparation method affects the properties of the mixtures. Here, we employ differential scanning calorimetry and broadband dielectric spectroscopy to investigate dispersions of a small-molecule drug (the Nordazepam anxiolytic) in biodegradable polylactide, both in the form of solvent-cast films and electrospun microfibres. We show that the dispersion of the same small-molecule compound can have opposite (plasticizing or antiplasticizing) effects on the segmental mobility of a biopolymer depending on preparation method, temperature, and polymer enantiomerism. We compare two different chiral forms of the polymer, namely, the enantiomeric pure, semicrystalline L-polymer (PLLA), and a random, fully amorphous copolymer containing both L and D monomers (PDLLA), both of which have lower glass transition temperature (Tg) than the drug. While the drug has a weak antiplasticizing effect on the films, consistent with its higher Tg, we find that it actually acts as a plasticizer for the PLLA microfibres, reducing their Tg by as much as 14 K at 30%-weight drug loading, namely, to a value that is lower than the Tg of fully amorphous films. The structural relaxation time of the samples similarly depends on chemical composition and morphology. Most mixtures displayed a single structural relaxation, as expected for homogeneous samples. In the PLLA microfibres, the presence of crystalline domains increases the structural relaxation time of the amorphous fraction, while the presence of the drug lowers the structural relaxation time of the (partially stretched) chains in the microfibres, increasing chain mobility well above that of the fully amorphous polymer matrix. Even fully amorphous homogeneous mixtures exhibit two distinct Johari–Goldstein relaxation processes, one for each chemical component. Our findings have important implications for the interpretation of the Johari–Goldstein process as well as for the physical stability and mechanical properties of microfibres with small-molecule additives

Reversible adiabatic temperature changes at the magnetocaloric and barocaloric effects in Fe49Rh51

We report on the adiabatic temperature changes (DT) associated with the magnetocaloric and barocaloric effects in a Fe49Rh51 alloy. For the magnetocaloric effect, data derived from entropy curves are compared to direct thermometry measurements. The agreement between the two sets of data provides support to the estimation of DT for the barocaloric effect, which are indirectly determined from entropy curves. Large DT values are obtained at relatively low values of magnetic field (2 T) and hydrostatic pressure (2.5 kbar). It is also shown that both magnetocaloric and barocaloric effects exhibit good reproducibility upon magnetic field and hydrostatic pressure cycling, over a considerable temperature range

Giant barocaloric effect in all-d-metal Heusler shape memory alloys

We have studied the barocaloric properties associated with the martensitic transition of a shape memory Heusler alloy Ni50Mn31.5Ti18.5 which is composed of all-d-metal elements. The composition of the sample has been tailored to avoid long-range ferromagnetic order in both austenite and martensite. The lack of ferromagnetism results in a weak magnetic contribution to the total entropy change, thereby leading to a large transition entropy change. The combination of such a large entropy change and a relatively large volume change at the martensitic transition gives rise to giant barocaloric properties in this alloy. When compared to other shape memory Heusler alloys, our material exhibits values for adiabatic temperature and isothermal entropy changes significantly larger than values reported so far for this class of materials. Furthermore, our Ni50Mn31.5Ti18.5 also compares favorably to the best state-of-the-art magnetic barocaloric materials