[The renewability of the groundwater resource in clean-up interventions: legal assumptions and technical implications of environmental sustainability]

[This Technical Note highlights some legal aspects and technical principles closely related to the concept of ground water renewability, in as far as this concept is considered when designing and implementing environmental clean-up projects and works. After outlining the quantitative importance of groundwater in meeting Italian water demand, some key points of the current regulations are commented on, and some practical guidelines are proposed which could be adopted during remediation of groundwater at contaminated sites, aiming at the protection and qualitative-quantitative restoration of the aquifers as an indication of sustainability]. [In Italian]

Covid and social distancing with a heterogenous population

Motivated by the Covid-19 epidemic, we build a SIR model with private decisions on social distancing and population heterogeneity in terms of infection-induced fatality rates, and calibrate it to UK data to understand the quantitative importance of these assumptions. Compared to our model, the calibrated benchmark version with constant mean contact rate significantly over-predicts the mean contact rate, the death toll, herd immunity and prevalence peak. Instead, the calibrated counterfactual version with endogenous social distancing but no heterogeneity massively under-predicts these statistics. We use our calibrated model to understand how the impact of mitigating policies on the epidemic may depend on the responses these policies induce across the various population segments. We find that policies that shut down some of the essential sectors have a stronger impact on the death toll than on infections and herd immunity compared to policies that shut down non-essential sectors. Furthermore, there might not be an after-wave after policies that shut down some of the essential sectors are lifted. Restrictions on social distancing can generate welfare gains relative to the case of no intervention. Milder but longer restrictions on less essential activities might be better in terms of these welfare gains than stricter but shorter restrictions, whereas the opposite might be the case for restrictions on more essential activities. Finally, shutting down some of the more essential sectors might generate larger welfare gains than shutting down the less essential sectors.

The role of inventories for the propagation of aggregate fluctuations: lessons for Bulgaria (1999–2019)

PurposeIn this study, inventories are introduced as a productive input into a real-business-cycle (RBC) setup augmented with the government.Design/methodology/approachThe model is calibrated to Bulgarian data for the period 1999–2019. The quantitative importance of the presence of inventories is investigated.FindingsThe quantitative effect of inventories is found to be important: decreasing consumption volatility and increasing employment variability. Those results, however, are at the expense of decreasing wage volatility and increasing investment volatility, and generally worsening the contemporaneous correlations of the main variables with output.Originality/valueFluctuations in inventory levels matter for business cycle fluctuations in Bulgaria, which is a novel result. Still, there is a need for more research on the incorporation of inventories into RBC models to better fit the Bulgarian experience.

Aromatic Plants from “Plateau des Cataractes”: Kinetic modeling of the extraction of leaf essential oils from Curcuma mangga (Valeton and Zijp) acclimatized in Congo-Brazzaville

Curcuma mangga Val. and Zijp is one of the many underutilized species of the genus Curcuma despite their proven interest as spice to color and enhance the taste of food, on the one hand, and as medicinal plants through essential oils extracted from different parts of the plant, on the other hand. Modeling the extraction in order to optimize the yield of essential oil is a pre requisite for the development of this species used as a spice in Congo-Brazzaville. The experimental results of the extraction of essential oil from the leaves analyzed, according to the phenomenological approach, validate both the kinetic model of the pseudo first order, when the washing step is neglected compared to the diffusion step and that of Peleg corresponding to a desorption in two steps (washing/diffusion). The main constituents of the oil adopt different desorption routes depending on their nature and their quantitative importance in the oil. Simple kinetics have been observed for sesquiterpenes present in relatively large amounts and complex for the monoterpenes in much smaller quantities.

The Neoclassical Growth Model and the Labor Share Decline

The labor share may be declining in the data, but it is often assumed constant in neoclassical growth models (NGM). We assess the quantitative importance of this discrepancy by comparing alternative calibration approaches featuring constant and declining labor shares. We find little difference in model performance. Our results derive from strong general equilibrium effects: while a declining labor share mechanically lowers wage growth, the investment response pushes wages back up. Hence, different models deliver nearly identical paths of macro aggregates. Numerous robustness checks (including a CES production function, different time periods, and calculations of the labor share) reinforce the similarity of performance across model specifications. We conclude that the NGM with a constant labor share is still an appropriate choice to study many standard macro aggregates.

The Missing “Cycle” Part and Other Thoughts on the Global Financial Cycle

The paper studies co-movement in capital flows, which gives rise to a phenomenon dubbed the global financial cycle. It first estimates a global common factor in capital flows using a factor model and draws inferences of its quantitative importance. Then the paper studies the cyclical properties of the extracted factor and concludes that, in general, its importance for capital flows is relatively limited. This may suggest that the Mundell-Fleming trilemma (as opposed to dilemma) still describes the trade-off faced by policymakers, and domestic policies play the primary role in maintaining macroeconomic stability.

An RBC model with non-Ricardian households: lessons for Bulgaria (1999–2018)

PurposeThe authors introduce non-Ricardian (“hand-to-mouth”) myopic agents into an otherwise standard real-business-cycle (RBC) setup augmented with a detailed government sector. The authors investigate the quantitative importance of the presence of nonoptimizing households for cyclical fluctuations in Bulgaria.Design/methodology/approachThe authors calibrate the RBC model to Bulgarian data for the period following the introduction of the currency board arrangement (1999–2018).FindingsThe authors find that the inclusion of such non-Ricardian households improves model performance along several dimensions and generally provides a better match vis-a-vis data, as compared to the standard model populated with Ricardian agents only.Originality/valueThis is a novel finding in the macroeconomic studies on Bulgaria using modern quantitative methods.

Situación y retos de la cooperación española para el fortalecimiento de las instituciones públicas

This article analyzes the situation and the current challenges of Spanish development assistance aimed at public institutional development. First, we try to define what we mean by the concept of "public institutional development", as against the idea of "increasing organizational resources". Secondly we analyze the quantitative importance of Spanish cooperation granted to such actions based mainly on the 2010 PACI tracking database. Then we the main strengths and weaknesses of our cooperation in this sector, on the basis of semi-open interviews carried out with technical personnel of three public cooperation agencies, 17 NGO and the evaluations carried out by the Directorate- General of planning and evaluation of development policies. The article ends with a series of conclusions and recommendations for the Spanish aid in this sector to be more effective.

The Decision to Move House and Aggregate Housing-Market Dynamics

Using data on house sales and inventories, this paper shows that housing transactions are driven mainly by listings and less so by transaction speed, thus the decision to move house is key to understanding the housing market. The paper builds a model where moving house is essentially an investment in match quality, implying that moving depends on macroeconomic developments and housing-market conditions. The number of transactions has implications for welfare because each transaction reduces mismatch for homeowners. The quantitative importance of the decision to move house is shown in understanding the U.S. housing-market boom during 1995–2003. (JEL: D83, E22, R31)

A Real-business-cycle Model with a Stochastic Capital Share: Lessons for Bulgaria (1999–2018)

We allow for a stochastic capital share into a real-business-cycle setup with a government sector. We calibrate the model to Bulgarian data for the period following the introduction of the currency board arrangement (1999–2018). We investigate the quantitative importance of the variability in capital share for cyclical fluctuations in Bulgaria. In particular, allowing for a stochastic capital share in the model increases variability of investment and employment, at the cost of decreasing the volatility of wages, and causing employment to become countercyclical. JEL Classification: E24, E32