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

Double acid etching treatment of dental implants for enhanced biological properties

Background: The topographical features on the surface of dental implants have been considered as a critical parameter for enhancing the osseointegration of implants. In this work, we proposed a surface obtained by a combination of shot blasting and double acid etching. The double acid etching was hypothesized to increase the submicron topography and hence further stimulate the biological properties of the titanium implant. Methods: The topographical features (surface roughness and real surface area), wettability and surface chemical composition were analyzed. Results: The results showed that the proposed method produced a dual roughness, mainly composed of randomly distributed peaks and valleys with a superimposed nanoroughness, and hence with an increased specific surface area. Despite the fact that the proposed method does not introduce significant chemical changes, this treatment combination slightly increased the amount of titanium available on the surface, reducing potential surface contaminants. Furthermore, the surface showed increased contact angle values demonstrating an enhanced hydrophobicity on the surface. The biological behavior of the implants was then assessed by culturing osteoblast-like cells on the surface, showing enhanced osteoblast adhesion, proliferation and differentiation on the novel surface. Conclusions: Based on these results, the described surface with dual roughness obtained by double acid etching may be a novel route to obtain key features on the surface to enhance the osseointegration of the implant. Our approach is a simple method to obtain a dual roughness that mimics the bone structure modified by osteoclasts and increases surface area, which enhances osseointegration of dental implants.Peer ReviewedPostprint (author's final draft

Efectos de la actividad ganadera en los lagos del Parque Nacional de Aigüestortes i Estany de Sant Maurici: aportes de nitrógeno y riesgo de eutrofización

Este capítulo contiene 16 páginas, 2 tablas, 11 figuras.El proyecto EGALA estudió el efecto de la actividad ganadera en los lagos del Parque Nacional de Aigüestortes i Estany de Sant Maurici especialmente por los aportes de N que representa y el riesgo de eutrofización que éste puede provocar. La cuestión se planteó a tres escalas espacio-temporales distintas: a escala de paisaje lacustre (en un conjunto de 19 cuencas lacustres) a escala de cuenca lacustre (en un conjunto de 12 lagos de la Vall de Sant Nicolau) y a escala de lago (valorando los efectos a lo largo de un transecto horizontal de la orilla al centro del lago). La concentración de N de los lagos no depende de manera simple de unos pocos factores. Aunque las variables relacionadas con la ganadería explican una fracción marginal de la variancia de las concentraciones de N, no parecen tener un papel significativo en la biogeoquímica de los lagos a escala de paisaje lacustre. Los lagos de mayor altitud con cuencas pequeñas y poco desarrollo de la vegetación y el suelo, acumulan una mayor cantidad de nitrato proveniente del depósito atmosférico. De manera opuesta los lagos situados en el fondo de los valles, con cuencas mayores cubiertas de pastos donde se concentra el ganado, presentan una menor concentración de nitrato en sus aguas, debido a una mayor retención del depósito en los suelos y la vegetación. Aunque la estima de la carga de N que moviliza anualmente la actividad ganadera en las distintas cuencas raramente supera el 20% del depósito atmosférico, se comprobó que es de una magnitud similar a la carga que realmente entra al lago. Esto podría indicar la importancia de la presencia de ganado en la movilización de un N que permanece retenido en la cuenca. Los lagos son sumideros de N, retienen las formas más oxidadas y exportan en menor medida las formas reducidas. El efecto directo de la presencia de ganado es detectable en la orilla del lago, no solo por el impacto físico y la limitación del desarrollo de la comunidad de macrófitos propia del sistema; sino porque se localiza una zona con mayores concentraciones de N, composición isotópica diferenciada y elevadas actividades microbianas. Por dilución y por mezcla con la masa de agua del lago, el efecto se diluye rá- pidamente al aumentar la profundidad de la columna de agua. En este proyecto se han encontrado evidencias de que el ganado tiene influencia sobre el estado trófico de los lagos, y aunque actualmente en general sea baja, se conoce que hay ciertas masas de agua más sensibles y que en tiempos pasados la presencia humana fue mayor y pudo producir un mayor grado de eutrofización de las aguas.El proyecto EGALA ha estado financiado por el Organismo Autónomo Parques Nacionales (nú- mero de referencia 124/2010).Peer reviewe

Deployment of ENEX enclosures in high‐mountain lake Redon (Spain)

The ENEX experiment in Lake Redon (Pyrenees) investigated the relationship between the changes in plankton stoichiometry, productivity, and community structure occurring during nutrient fluctuations in P‐limited conditions. Columnar enclosures were used for treatments varying P availability, N:P imbalance, and N source. C:N:P seston ratios were stable in P‐limited conditions, with loose coupling with productivity, nutrient supply ratios, and species dominance. The stoichiometric ratios shifted to Redfield proportions in P‐repleted conditions. The results suggest a complex regulation of P scarcity in planktonic communities that goes beyond immediate acclimation growth responses and might include alternative physiological and biogeochemical states

Microbial food web components, bulk metabolism, and single-cell physiology of piconeuston in surface microlayers of high-altitude lakes

12 páginas, 4 tablas, 3 figuras.Sharp boundaries in the physical environment are usually associated with abrupt shifts in organism abundance, activity ,and diversity. Aquatic surface microlayers (SML) from a steep gradient between two contrasted environments, the atmosphere and surface waters, where they regulate the gas exchange between both environments. They usually harbor an abundant and active microbial life: the neuston. Few ecosystems are subjected to such a high UVR regime as high altitude lakes during summer. Here, we measured bulk estimates of heterotrophic activity, community structure and single-cell physiological properties by flow cytometry in 19 high-altitude remote Pyrenean lakes and compared the biological processes in the SML with those in the underlying surface waters. Phototrophic picoplankton (PPP) populations, were generally present in high abundances and in those lakes containing PPP populations with phycoerythrin (PE), total PPP abundance was higher at the SML .Heterotrophic nanoflagellates (HNF) were also more abundant in the SML. Bacteria in the SML had lower leucine incorporation rates, lower percentages of “live” cells, and higher numbers of highly-respiring cells ,likely resulting in a lower growth efficiency. No simple and direct linea rrelationships could be found between microbial abundances or activities and environmental variables, but factor analysis revealed that, despite their physical proximity ,microbial life in SML and underlyingwaters was governed by different and independent processes. Overall, we demonstrate that piconeuston in high altitude lakes has specific features different from those of the picoplankton ,and that they are highly affected by potential stressful environmental factors, such as high UVR radiation.This work was supported by grants 2009SGR/1177 “Grup d’estructura i funcio de xarxes tròfiques microbianes planctòniques” and 2009SGR/361 “Grup d’Ecologia dels Canvis Ambientals, GECA” from Generalitat de Catalunya, AERBAC-2 178/2010 (to EOC) and EGALA 124/2010 (MF, LC) from the Ministerio de Medio Ambiente- Red de Parques Nacionales, and PIRENA CGL2009-13318 (EOC) and NITROPIR CGL2010-19373 (MF, LC) from MINECO. HS’s work was supported by CNPq and FAPESP (Process: 2014/ 14139-3).Peer reviewe

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

Episodic nutrient enrichments stabilise protists coexistence in planktonic oligotrophic conditions

1. Seasonal compositional changes in plankton communities are usually considered as species replacements. Provided the enormous number of individuals integrating the communities and our limited capacity for counting and determining a substantial proportion of them, it may happen that we would only be observing alternative population peaks of a large number of coexisting species. The contemporary coexistence theory addresses coexistence in communities of competing species considering simultaneously relative fitness inequalities and stabilising niche differences as components of average long-term growth rates. Here, we experimentally show that response patterns predicted by the theory occur when varying nutrient pulses fertilise the planktonic community. 2. We used gently self-filling 100 L enclosures to minimise disturbance of the initial community and different pulse P and N additions to manipulate the apparently species-poor epilimnetic community of an ultraoligotrophic P-limited lake. We measured and compared protist species growth response to a gradient of P enrichment and another of N stoichiometric imbalance. The P and N levels selected were within the oligotrophic seasonal and interannual variation of the lake, plus some extreme treatments providing mesotrophic conditions of remote regions affected by N atmospheric contamination. All treatments were replicated using ammonium or nitrate alternatively as N source. 3. Most protist species ¿ recorded across seasons in previous studies in this lake ¿ were recovered, indicating a persistent assemblage of species that is seasonally-hidden to observation. Recovery included some rare species only observed in the slush layers of the seasonal snow and ice cover. Coexistence stabilising mechanisms were indicated by treatment response features such as frequency-dependent growth, inverse relationship between fitness inequality and niche differentiation proxies, high-rank taxonomic levels clustering across the limiting nutrient gradient but segregation at the species level according to the type of nitrogen supply, and resting stage development depending on nutrient conditions. Response similarities between autotrophic and heterotrophic organisms indicate a network of interactions that may reinforce coexistence. 4. Synthesis. The results indicate that many planktonic protist species in oligotrophic waters can show stable long-term non-equilibrium coexistence by alternately recovering from very low densities when episodic nutrient enrichments ¿ of varying P and N amounts and composition ¿ occur