Long-run relationship between crop-biodiversity and cereal production under the CAP reform: evidence from Italian regions

Biodiversity has a prominent role in defining and preserving ecosystem well-being; the analysis of biodiversity effects on agricultural production is well documented. The paper offers empirical evidence on the role of intra-species biodiversity in sustaining cereal production within Italian regions, covering a time span (1989-2007) which accounts for the important CAP policy reforms. A Cobb-Douglas production function that includes both biodiversity and subsidies as control variables is estimated for 20 Italian regions, controlling for both cross-sectional heterogeneity and the dynamic structure of agricultural production. Different estimation methods are compared, including Mean Group and Pooled Mean Group estimators which allow for the possibility of potential non stationarity of the series and heterogeneous parameters across-groups. We find clear evidence of significant long-run relationships between biodiversity and cereal production; moreover, the evidence on the role of PAC intervention measures is less clear-cut, showing a potentially negative effect on production along the period under analysis that can be attributed to the aforementioned policy shift.

The classical notion of competition revisited

We compare and analyse two different conceptions of market competition: the walrasian notion of perfect competition and the Classical notion of free competition: while the former may be described as an equilibrium state in which atomistic agents treat prices parametrically, the latter is a situation in which agents, endowed by market power, fix prices strategically. We show that price undercutting or outbidding are the typical phenomena that, for the Classical authors, may be observed in a market characterized by free competition. We investigate some problematic aspects of the neoclassical notion of perfect competition and we reconstruct the Classical theory of free competition, as developed, in particular, by Adam Smith and Karl Marx, in the light of the modern notion of mixed strategies equilibria.Classical Economics, Competition, Adam Smith, Karl Marx, mixed strategies

Metrology Infrastructure for Energy and Power Quality in DC Railway Systems

L'abstract è presente nell'allegato / the abstract is in the attachmen

Differences in Types and Severity of Consequences of High-Stakes Testing as Realized Between Low and High Performing High Schools and the Impact on the Instructional Programs in Their Schools

The purpose of this study was to investigate the role of the Pennsylvania System of School Assessment (PSSA) on the beliefs of teachers and principals, and the impact on the instructional program in their schools. This study collected data on (a) teachers\u27 perceptions of the PSSA, (b) how the program affected instructional practices, and to what extent teachers changed their instructional practices, and (c) what factors, if any, may have influenced these changes. Certified teachers and principals from three high performing and three low performing secondary (9-12 grade) schools in northwestern Pennsylvania were included in this study. Teachers volunteering to participate completed and returned the 54-item, three-part, Likert-style survey indicating to what extent he or she may have changed or altered the use of instructional strategies and techniques used in their classroom, as well as what factors influenced changes in educational practices. Results indicate that the use instructional strategies have changed since the implementation of the PSSA high stakes exams. Contrary to findings in the literature that testing will narrow the curriculum and force teachers to drill and practice the identified content, teachers in all six of the participating schools have increased the use of instructional strategies and tools, considered to be consistent with development of high order skills and best practice, and a decline in use of six items that do not properly involve students in learning. These results lead one to believe that the PSSA assessments did contribute to the changes to instructional classroom strategies as implemented by teachers

The Classical notion of competition revisited

The paper seeks to fill a lacuna within classical economics concerning the process of market price determination in situations of market disequilibrium. To this aim, first we distinguish the classical notion of free competition from the Walrasian notion of perfect competition and we argue that the latter is beset with some theoretical difficulties alien to the former. Second, we reconstruct in some detail Smith\u2019s and Marx\u2019s views concerning market price determination and show that Marx\u2019s extensive use of metaphors and numerical examples foreshadows the modern taxonomy of buyers\u2019 market, sellers\u2019 market, and mixed strategy equilibrium in the capacity space of a standard Bertrand duopoly model. Finally, we highlight similarities and differences between the classical notion of competition and contemporary Bertrand competition models

Strategy and Sample Selection -- A Strategic Selection Estimator

The development and proliferation of strategic estimators has narrowed the gap between theoretical models and empirical testing. But despite recent contributions that extend the basic strategic estimator, researchers have continued to neglect a classic social science phenomenon: selection. Compared to non-strategic estimators, strategic models are even more prone to selection effects. First, external shocks or omitted variables can lead to correlated errors. Second, because the systematic parts of actors? utilities usually overlap on certain key variables, the two sets of explanatory variables are correlated. As a result, both the systematic and the stochastic components can be correlated. However, given that the estimates for the first mover are computed based on the potentially biased predicted probabilities of the second actor, we also generate biased estimates for the first actor. In applied work researchers neglect the potential shortcomings due to selection bias. This paper presents an alternative strategic estimator that takes selection into account and allows scholars to obtain consistent, unbiased, and efficient estimates in the presence of both selection and strategic action. I present a Monte Carlo analysis as well as a real world application to illustrate the superior performance of this estimator relative to the standard practice

Energy Efficiency Improvement with Reversible Substations for Electrified Transportation Systems

More and more often overall energy efficiency of an electrified transportation system appears as a target of new constructions, sometimes with incomplete definitions of performance indexes to assess that target has been reached. A worked out example is based on the introduction of reversible substations. Reversible substations are a method to improve energy efficiency, whose application in an existing system can be progressive and does not require large traffic intensity to be effective. Their effectiveness depends on some system parameters (nominal catenary voltage in particular). A simulation model fed with experimental data from a line section of Metro de Madrid is used to demonstrate the operation and optimization of reversible substations

Gold supported on iron oxy-hydroxides: a versatile tool for the synthesis of fine chemicals

A comprehensive overview on gold supported on iron oxy-hydroxides as tool for the synthesis of fine chemicals is given. We will discuss on the catalytic activity of gold supported on iron oxy-hydroxides in several reactions of potential industrial interest, comprising the selective oxidation of primary alcohol to aldehyde, the selective reduction of α,s unsaturated aldehydes and ketones to the corresponding a,b unsaturated alcohols. Furthermore, a significant application of gold supported on iron oxy-hydroxides is the direct synthesis of hydrogen peroxide from H2 and O2. The versatility showed by Au supported on oxy-hydroxides catalysts is an aspect of great importance for industrial applications

Catalytic Processes for The Valorisation of Biomass Derived Molecules

In the last decades, inedible lignocellulosic biomasses have attracted significant attention for being abundant resources that are not in competition with agricultural land or food production and, therefore, can be used as starting renewable material for the production of a wide variety of platform chemicals. The three main components of lignocellulosic biomasses are cellulose, hemicellulose and lignin, complex biopolymers that can be converted into a pool of platform molecules including sugars, polyols, alchols, ketons, ethers, acids and aromatics. Various technologies have been explored for their one-pot conversion into chemicals, fuels and materials. However, in order to develop new catalytic processes for the selective production of desired products, a complete understanding of the molecular aspects of the basic chemistry and reactivity of biomass derived molecules is still crucial. This Special Issue reports on recent progress and advances in the catalytic valorization of cellulose, hemicellulose and lignin model molecules promoted by novel heterogeneous systems for the production of energy, fuels and chemicals

Aggregation Among Binary, Count, and Duration Models: Estimating the Same Quantities from Different Levels of Data

Binary, count, and duration data all code discrete events occurring at points in time. Although a single data generation process can produce all of these three data types, the statistical literature is not very helpful in providing methods to estimate parameters of the same process from each. In fact, only a single theoretical process exists for which known statistical methods can estimate the same parameters—and it is generally used only for count and duration data. The result is that seemingly trivial decisions about which level of data to use can have important consequences for substantive interpretations. We describe the theoretical event process for which results exist, based on time independence. We also derive a set of models for a time-dependent process and compare their predictions to those of a commonly used model. Any hope of understanding and avoiding the more serious problems of aggregation bias in events data is contingent on first deriving a much wider arsenal of statistical models and theoretical processes that are not constrained by the particular forms of data that happen to be available. We discuss these issues and suggest an agenda for political methodologists interested in this very large class of aggregation problems.Statistic