Kleene Algebra with Converse

International audienceThe equational theory generated by all algebras of binary relations with operations of union, composition, converse and reflexive transitive closure was studied by Bernátsky, Bloom, Ésik, and Stefanescu in 1995. We reformulate some of their proofs in syntactic and elementary terms, and we provide a new algorithm to decide the corresponding theory. This algorithm is both simpler and more efficient; it relies on an alternative automata construction, that allows us to prove that the considered equational theory lies in the complexity class PSPACE. Specific regular languages appear at various places in the proofs. Those proofs were made tractable by considering appropriate automata recognising those languages, and exploiting symmetries in those automata

Centralization and Accountability: Theory and Evidence from the Clean Air Act.

This paper studies fi scal federalism when voter information varies across regions. We develop a model of political agency with heterogeneously informed voters. Rent-seeking politicians provide public goods to win the votes of the informed. As a result, rent extraction is lower in regions with higher information. In equilibrium, electoral discipline has decreasing returns. Thus, political centralization efficiently reduces aggregate rent extraction. The model predicts that a region' s benefi ts from centralization are decreasing in its residents' information. We test this prediction using panel data on pollutant emissions across U.S. states. The 1970 Clean Air Act centralized environmental policy at the federal level. In line with our theory, we fi nd that centralization induced a differential decrease in pollution for uninformed relative to informed states

On the Design of Constructively Aligned Educational Unit

Modern pedagogy is moving away from traditional transmissive approaches, and it is extensively embracing constructive theory of learning. A prominent practical embodiment of this paradigm shift is a method called Constructive Alignment (CA). This approach focuses on learners’ actions and starts from a clear communication of the Intended Learning Outcomes (ILOs) of the focal unit. ILOs are made of content, a context, and an Educational Goal Verb (EGV). According to the Bloom Taxonomy, the EGV is the core of an ILO and refers to the action the learners are expected to be able to master after completing the educational unit. The ILO is then aligned to the course activity using the EGV (i.e., EGVs are enacted through Teaching and Learning Activities (TLAs) and verified through Assessment Tasks (ATs)). Despite the ILO definition being extensively investigated and described, the extant literature has poorly explored how to devise suitable TLAs and ATs, lacking comprehensive contributions that identify and describe the different kinds of TLAs and ATs available to course designers. In view of the above gap, the authors searched and reviewed the literature (scientific papers (i.e., top-down, deductive approach)) and practices in higher education (university websites and blogs (i.e., bottom-up, inductive approach)) to identify all the possible sources of TLA and AT descriptions available. The results propose standardized templates that support the course design process, providing extensive descriptions of TLA and AT based on the best practices identified. The proposed templates include the core dimensions that proved to be suitable for designing traditional and remote-learning activities. Finally, the examples provided in the paper show how to use these templates on a few kinds of selected on-campus and digital TLAs and ATs from the educational units identified in the Erasmus+ MAESTRO project, which is based on Industry 4.0 technological enablers and their application in support of manufacturing sustainability

Valorisation of by-products from soybean (Glycine max (L.) Merr.) processing

In recent years, increased awareness of the health benefits associated with consuming soy-based foods, knowledge of milk-related allergies and a move towards more sustainable food production have led to an increase in the number of available soy-based products. The biggest producers in the world, the USA, South America and China, are from the Pacific region. This enormous production is accompanied by the accumulation of related by-products, in particular, a substance that is known as okara. Okara is a paste that is rich in fibre (50%), protein (25%), fat (10%), vitamins and trace elements. Its proper use would lead to economic advantages and a reduction in the potential for polluting the environment. Its high fibre content and low production costs mean that it could also be used as a dietary supplement to prevent diabetes, obesity and hyperlipidaemia. Chemical or enzymatic treatment, fermentation, extrusion, high pressure and micronisation can all increase the soluble fibre content, and thus improve nutritional quality and processing properties. However, the product also degrades rapidly due to its high moisture content (70–80%), which makes it difficult to handle and expensive to dry by conventional means. The aim of this paper is therefore to thoroughly study the existing literature on this subject in order to develop a general protocol for okara exploitation and valorisation. A cost/benefit analysis could drive the design of eco-friendly, sustainable protocols for the preparation of high-value nutritional products

Water Defluoridation: Nanofiltration vs Membrane Distillation

Nowadays, fluoride contamination of drinking water is a major problem for various countries, because high concentrations of fluoride pose a risk of dental and skeletal fluorosis. Over past years, membrane nanofiltration (NF) has been proposed as convenient defluoridation technology. However, NF cannot be applied to water systems with high fluoride concentration, and the disposal of the membrane concentrate remains an issue. In this work, we compared a commercial polyester NF membrane and a polypropylene hollow-fiber membrane distillation (MD) module for their ability to remove fluoride ions from water in the presence of hardness ions and organic fouling agents. The NF membrane can offer more than 10 times higher water productivity than MD, under realistic gradients of temperature and pressure, respectively. Despite that, after reaching a concentration factor of about 3, fouling and scaling caused the flux to drop to about 80% with respect to its initial value. Moreover, F- retention decreased from 90% to below 80%, thus providing a permeate of scarce quality. MD was operated in the direct-contact mode on a polypropylene hollow-fiber membrane, which was charged with a hot feed flow (average T = 58 °C) on one side and a cooled (20 °C) permeate flow of distilled water on the other side. The concentration of fluoride ions in the permeate was always below the detection limit of our electrode (0.2 ppm), regardless of the fluoride concentration in the feed. Moreover, the MD module showed higher resistance to fouling and scaling than NF, and CaF2 crystals were recovered from the MD concentrate after cooling. These results suggest that the synergic combination of the two techniques might be beneficial for the purification of fluoride-contaminated water systems: MD can be used to further concentrate the NF retentate, thus producing high-purity water and recovering CaF2 crystals.Fil: Moran Ayala, Lucia Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Paquet, Marie. University of Aalborg; DinamarcaFil: Janowska, Katarzyna. University of Aalborg; DinamarcaFil: Jamard, Paul. University of Aalborg; DinamarcaFil: Quist Jensen, Cejna A.. University of Aalborg; DinamarcaFil: Bosio, Gabriela Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Martire, Daniel Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Fabbri, Debora. Università di Torino; ItaliaFil: Boffa, Vittorio. University of Aalborg; Dinamarc