¿Vuelve la extensión rural?: Reflexiones y propuestas agroecológicas vinculadas al retorno y fortalecimiento de la extensión rural en Latinoamérica

La actual crisis social y ambiental instala la perspectiva de la sustentabilidad como el paradigma emergente capaz de reconstruir el proceso económico dentro de una nueva racionalidad productiva fundada en la diversidad cultural, la equidad social y la relación ecológica con la naturaleza. La sustentabilidad es un concepto en construcción y la extensión rural puede hacer importantes contribuciones a su desarrollo. En este trabajo se analizan las trayectorias históricas seguidas por la extensión convencional y alternativa. Se demuestra como la trayectoria de la extensión convencional finalizó en la privatización de la misma, lo que significa su desaparición como disciplina científica. Por el contrario, la trayectoria de la extensión alternativa generó desarrollos teóricos y metodológicos congruentes con la nueva perspectiva de la sustentabilidad. De allí que se proponga recuperar y recrear la extensión rural a partir de su historia alternativa como base para nuevos desarrollos teóricos, metodológicos e instrumentales necesarios para la construcción de sociedades sustentables.The actual social and environmental crisis sets the perspective of sustentability as the emergent paradigm for the rebuilding of the economic process into a new productive rationality based in cultural diversity, social equity and ecological relationship with nature. Sustentability is an in building concept and rural extension can make important contributions to its development. In this study the historic trajectories followed by conventional and alternative extension are analysed. The way in which conventional extension trajectory ended in its own privatization is demonstrated. In contrast, the way in which alternative extension generated methodological and theorical developments according with the new perspective of sustentability is discussed. To recover and to recreate rural extension from its alternative history as a base for new theoric, methodological and instrumental developments, that are necessary for the construction of sustentable societies is proposed

Elementos para el estudio de la dinámica y evolución histórica de la extensión rural en Argentina

En este trabajo se han identificado y analizado algunos momentos significativos de la historia de la extensión rural argentina. Para ello, primero se ha desarrollado un marco conceptual sistémico, que permitió abordar la realidad compleja, multidimensional y dinámica de la extensión rural. Así, se ha construido una imagen metafórica comprehensiva compuesta por un conjunto de cinco dimensiones; dos de ellas contexto-estructurales (paradigma social y/o del desarrollo y perspectivas teóricas del pensamiento social agrario), y tres propias de la extensión (enfoques de extensión, sistemas de extensión y praxis/práctica extensionista). Los momentos que se seleccionaron y estudiaron fueron: 1- La extensión rural de los pueblos originarios, antes de la llegada de los españoles a nuestro territorio, para revalorizar su existencia y el desarrollo de una “extensión” indígena; 2- La extensión rural dual generada por la oligarquía argentina, funcional al modelo agroexportador; 3- La extensión rural educativa y crítica de la Argentina industrial y democrática; 4- La extensión rural transferencista, producto del Estado autoritario impulsor de la “revolución verde”, y finalmente; 5- La mercantilización de la extensión rural y su reverso: la extensión rural pública compensadora y focalizada. En el trabajo se puede ver que la evolución de la extensión rural sigue dos trayectorias históricas congruentes con la contradicción principal que expresan las luchas por el poder en la Argentina; por un lado entre las fuerzas económicas, políticas y militares que impulsaron e impulsan procesos neocoloniales de concentración y exclusión y, por el otro, las fuerzas sociales y políticas que los enfrentaron y enfrentan con propuestas alternativas emancipadoras, más autónomas e independientes.In this work, some significant moments in the history of the argentine rural extension have been identified and analyzed. To do this, a systemic conceptual framework, which allowed to address the complex, multidimensional and dynamic reality of rural extension has been developed. Thus, a comprehensive metaphorical image composed of a set of five dimensions has been built; two of these context-structural (social and/or development paradigm and theoretical perspectives of agrarian social thought), and three concerning extension (extension approaches, extension systems and praxis/practical of extension). The moments that were selected and studied were: 1- the rural extension of native peoples before the arrival of the Spaniards to our territory to revalue their existence and development of an indigenous "extension"; 2- The dual rural extension generated by the argentine oligarchy, functional to the agricultural exportation model; 3- The educational and critical rural extension of the industrial and democratic Argentina; 4- The rural extension focused in transference, product of the authoritarian State promoter of the "green revolution", and finally; 5- the mercantilization of the rural extension and its reverse: the compensatory and focused public rural extension. It can be seen in this work, that the evolution of rural extension follows two historical paths, congruent with the main contradiction that express the power struggles in Argentina; on one hand between the economic, political and military forces that propelled and propel neocolonial processes of concentration and exclusion and, on the other hand, the social and political forces that faced and face them with alternative emancipatory proposals, more autonomous and independent

The optimality of syntactic dependency distances

It is often stated that human languages, as other biological systems, are shaped by cost-cutting pressures but, to what extent? Attempts to quantify the degree of optimality of languages by means of an optimality score have been scarce and focused mostly on English. Here we recast the problem of the optimality of the word order of a sentence as an optimization problem on a spatial network where the vertices are words, arcs indicate syntactic dependencies and the space is defined by the linear order of the words in the sentence. We introduce a new score to quantify the cognitive pressure to reduce the distance between linked words in a sentence. The analysis of sentences from 93 languages representing 19 linguistic families reveals that half of languages are optimized to a 70% or more. The score indicates that distances are not significantly reduced in a few languages and confirms two theoretical predictions, i.e. that longer sentences are more optimized and that distances are more likely to be longer than expected by chance in short sentences. We present a new hierarchical ranking of languages by their degree of optimization. The statistical advantages of the new score call for a reevaluation of the evolution of dependency distance over time in languages as well as the relationship between dependency distance and linguistic competence. Finally, the principles behind the design of the score can be extended to develop more powerful normalizations of topological distances or physical distances in more dimensions

Optimality of syntactic dependency distances

It is often stated that human languages, as other biological systems, are shaped by cost-cutting pressures but, to what extent? Attempts to quantify the degree of optimality of languages by means of an optimality score have been scarce and focused mostly on English. Here we recast the problem of the optimality of the word order of a sentence as an optimization problem on a spatial network where the vertices are words, arcs indicate syntactic dependencies, and the space is defined by the linear order of the words in the sentence. We introduce a score to quantify the cognitive pressure to reduce the distance between linked words in a sentence. The analysis of sentences from 93 languages representing 19 linguistic families reveals that half of languages are optimized to a 70% or more. The score indicates that distances are not significantly reduced in a few languages and confirms two theoretical predictions: that longer sentences are more optimized and that distances are more likely to be longer than expected by chance in short sentences. We present a hierarchical ranking of languages by their degree of optimization. The score has implications for various fields of language research (dependency linguistics, typology, historical linguistics, clinical linguistics, and cognitive science). Finally, the principles behind the design of the score have implications for network science.Peer ReviewedPostprint (published version

Isotopic study of the influence of oxygen interaction and surface species over different catalysts on the soot removal mechanism

In order to improve the catalytic formulations for soot removal in after-treatment emission control technologies for gasoline and diesel engine vehicle, an isotopic study was approached using transitory labeled oxygen response method over model catalysts that allows the unraveling of soot oxidation mechanism. Ce-based materials promote oxygen exchange associated with the high population of lattice oxygen species (O2-) denoted as OI type. The incorporation of praseodymium produces a Pr3+ enrichment that decrease the energy for oxygen release and increase oxygen mobility through surface and subsurface oxygen centers (OII type) depending on the synthesis procedure. For PtBaK catalyst, OIII species are responsible for oxygen exchange. Gas-solid reaction between soot and gas phase molecular oxygen is responsible for direct uncatalyzed soot oxidation. For ceria containing catalysts, low-temperature soot removal takes place through the intervention of lattice atomic species and superoxide species. For DPNR model catalyst, PtBaK/Al2O3, the soot elimination occurs with the intervention OIII type centers. In the presence NO, the assisted and cooperative mechanism due to NO2 and the intervention of the adsorbed nitrate species on the trimetallic catalyst enhances soot removal capacity.MCR acknowledges the postdoctoral fellowship obtained from the University of Malaga. MCR, CH, MAL and LJA want to thank the financial support of CTQ 2017-87909R project. MCR also want to thank the University of Alicante for the financial support for the internship (INV19-07). JCMM and AGG gratefully acknowledge the financial support of Generalitat Valenciana (PROMETEO/2018/076 project) and the Spanish Ministry of Science, Innovation and Universities (PID2019-105542RB-I00 project) and the UE-FEDER funding. JCMM also acknowledges Spanish Ministry of Science, Innovation and Universities for the financial support through a FPU grant (FPU17/00603)

Power system reliability considering combined cycle plants

In the nineties in Argentina, the growth of thermal power generation was mainly based on combined cycle plants. Currently, one problem associated with the use of combined cycle plants is the fact that they need to share the use of natural gas with commercial, industrial and domestic uses. Hence, the natural gas availability is becoming a critical issue. Therefore, power system reliability studies must consider fuel availability into the models, and as a consequence, reliability models must take into account the joint operation of electrical generation and natural gas systems. The aim of this paper is to evaluate the influence of combined cycle plants on reliability studies applied to system generation capacity and their dependency on natural gas availability. Monte Carlo simulation method is used to determine reliability indices such as Loss of Load Expectation, Loss of Energy Expectation, Loss of Load Frequency, and Loss of Load Duration. The IEEE RTS 96 test system is used as the base system, with is modified in order to incorporate combined cycle plants.Fil: Alemany, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ingeniería. Departamento de Electricidad y Electrónica; Argentina. Centro de Investigaciones Cientificas ; Facultad de Ciencias Exactas Fisicas y Naturales ; Universidad Nacional de Cordoba;Fil: Moitre, Diego Carlos Alberto. Universidad Nacional de Río Cuarto; Argentina. Pontificia Universidad Católica de Chile; ChileFil: Magnago, Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ingeniería. Departamento de Electricidad y Electrónica; Argentina. Centro de Investigaciones Cientificas ; Facultad de Ciencias Exactas Fisicas y Naturales ; Universidad Nacional de Cordoba; . Texas A&M University; Estados Unido

Dopamine interaction with a polyamine cryptand of 1H-pyrazole in the absence and in the presence of Cu(II) ions. Crystal structure of [Cu2(H21L](ClO4)3·2H2O

The crystal structure of the binuclear Cu2+ complex [Cu2(H21L)](ClO4)3·2H2O of the cryptand L = 1,4,7,8,11,14,17,20,21,24,29,32,33,36-tetradecaazapentacyclo[12.12.12.1^(6,9).1^(19,22),1,^31,34]hentetraconta-6,9(41),19(40), 21,31,34(39)-hexaene is presented; evidence for the formation in solution of binary L–dopamine and ternary Cu2+–L– dopamine complexes is presented.Escarti Alemany, Francisco, [email protected] ; Garcia-España Monsonis, Enrique, [email protected] ; Latorre Saborit, Julio, [email protected]

Tau weak dipole moments from azimuthal asymmetries

We show that transverse and normal single-$tau$ polarization of $tau$ pairs produced at $e^+$ $e^-$ unpolarized collisions, at the $Z$ peak, are sensitive to weak (magnetic and electric) dipole moments of the $tau$. We also show how these components of the $\tau$ polarization are accessible by measuring appropriate azimuthal asymmetries in the angular distribution of its decay products. Sensitivities of the order of $10^{-18}$ $e\cdot cm$, for the weak-electric dipole moment, and $10^{-4}$ ($10^{-3}$), for the real (imaginary) part of the weak-magnetic dipole moment of $\tau$, may be achieved. Compatible bounds are also presented from spin-spin correlated asymmetries.Comment: Talk given at the TAU'98 Workshop, September 1998, Santander, Spain. 8 pages, 2 figure