Bordering spaces in the South American south. Proposals for a conceptual model for their study

Se presenta un modelo conceptual para abordar el estudio geográfico comparado de los espacios fronterizos formados entre estados nacionales. La sistematización empírica en la que se basa la propuesta se viene realizando en el ámbito del sur de sudamericano, entendiendo por tal al área donde se diferenciaron, a lo largo de los siglos XIX y XX, los territorios de seis estados nacionales: Argentina, Bolivia, Brasil, Chile, Paraguay y Uruguay. Este artículo apunta a renovar, desde la tradición geográfica crítica, los estudios sobre fronteras de la Argentina, a partir de una mirada relacional y multiescalar en la construcción de los territorios. El modelo aludido reconoce seis componentes principales para el estudio de los espacios fronterizos: diferenciación territorial, fronterización, territorios interiores, territorios exteriores, lugares de frontera y movilidades. Cada uno de estos componentes será presentado a partir de ejemplos tomados del área de estudio.This is a conceptual model for the comparative geographical study of border areas formed between national states. The empirical systematization this proposal is based on has been carried out in southern South America, defined as the area where, during the nineteenth and twentieth centuries, the territories of six national states were differentiated: Argentina, Bolivia, Brazil, Chile, Paraguay and Uruguay. This article aims to renew the studies on Argentine borders, from a critical geographic tradition point of view and based on a relational and mul-tiscalar aspect on the construction of territories. The model recognizes six main components for the study of border areas: territorial differentiation, frontierization, internal territories, external territories, border areas and mobilities.Fil: Benedetti, Alejandro. Universidad de Buenos Aires. Facultad de Filosofía y Letras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Los espacios fronterizos binacionales del sur sudamericano en perspectiva comparada

O artigo tem duas partes. Na primeira parte, propomos um conjunto de definições relativas a fronteiras como um fenômeno social, com foco em: o vínculo conceitual entre território e fronteiras; fronteiras como conceito relacional e processual; as fronteiras e o sentido de lugar; a relação entre fronteira, multiescalaridade e mobilidades; a distinção entre limite, fronteira e descontinuidade; a fronteira como um sistema de objetos e ações. A segunda parte vai oferecer uma caracterização das áreas de fronteira do sul da América do Sul, através de uma abordagem cartográfica em seis camadas de informação: (1) a diferenciação territorial, (2) frontierização, (3) os territórios interiores, (4) territórios externos; (5) lugares de fronteira, e (6) mobilidades.Fil: Benedetti, Alejandro. Universidad de Buenos Aires. Facultad de Filosofía y Letras. Instituto Interdisciplinario Tilcara; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Fronteras y Movilidades

A partir de la obra publicada por Friedrich Ratzel (1897), las fronteras entre estados nacionales (en adelante solo fronteras) se han convertido en objeto de estudio privilegiado de la geopolítica [...]Fil: Dorfman, Adriana. Universidade Federal do Rio Grande do Sul. Departamento de Geografia; BrasilFil: Benedetti, Alejandro. Universidad de Buenos Aires. Facultad de Filosofía y Letras. Instituto Interdisciplinario Tilcara; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Quantum-Assisted Learning of Hardware-Embedded Probabilistic Graphical Models

Mainstream machine-learning techniques such as deep learning and probabilistic programming rely heavily on sampling from generally intractable probability distributions. There is increasing interest in the potential advantages of using quantum computing technologies as sampling engines to speed up these tasks or to make them more effective. However, some pressing challenges in state-of-the-art quantum annealers have to be overcome before we can assess their actual performance. The sparse connectivity, resulting from the local interaction between quantum bits in physical hardware implementations, is considered the most severe limitation to the quality of constructing powerful generative unsupervised machine-learning models. Here we use embedding techniques to add redundancy to data sets, allowing us to increase the modeling capacity of quantum annealers. We illustrate our findings by training hardware-embedded graphical models on a binarized data set of handwritten digits and two synthetic data sets in experiments with up to 940 quantum bits. Our model can be trained in quantum hardware without full knowledge of the effective parameters specifying the corresponding quantum Gibbs-like distribution; therefore, this approach avoids the need to infer the effective temperature at each iteration, speeding up learning; it also mitigates the effect of noise in the control parameters, making it robust to deviations from the reference Gibbs distribution. Our approach demonstrates the feasibility of using quantum annealers for implementing generative models, and it provides a suitable framework for benchmarking these quantum technologies on machine-learning-related tasks.Comment: 17 pages, 8 figures. Minor further revisions. As published in Phys. Rev.

A generative modeling approach for benchmarking and training shallow quantum circuits

Hybrid quantum-classical algorithms provide ways to use noisy intermediate-scale quantum computers for practical applications. Expanding the portfolio of such techniques, we propose a quantum circuit learning algorithm that can be used to assist the characterization of quantum devices and to train shallow circuits for generative tasks. The procedure leverages quantum hardware capabilities to its fullest extent by using native gates and their qubit connectivity. We demonstrate that our approach can learn an optimal preparation of the Greenberger-Horne-Zeilinger states, also known as "cat states". We further demonstrate that our approach can efficiently prepare approximate representations of coherent thermal states, wave functions that encode Boltzmann probabilities in their amplitudes. Finally, complementing proposals to characterize the power or usefulness of near-term quantum devices, such as IBM's quantum volume, we provide a new hardware-independent metric called the qBAS score. It is based on the performance yield in a specific sampling task on one of the canonical machine learning data sets known as Bars and Stripes. We show how entanglement is a key ingredient in encoding the patterns of this data set; an ideal benchmark for testing hardware starting at four qubits and up. We provide experimental results and evaluation of this metric to probe the trade off between several architectural circuit designs and circuit depths on an ion-trap quantum computer.Comment: 16 pages, 9 figures. Minor revisions. As published in npj Quantum Informatio

Quatro conceitos de fronteira de grande extensão terrestre, claves para a construção do pensamento geográfico da Argentina

Este artículo revisará la emergencia y alguno de los sentidos otorgados a cuatro conceptos de frontera que fueron clave en la construcción territorial de la Argentina y que permitieron establecer algunos de sus lineamientos geopolíticos para la escala nacional. Esos cuatro conceptos son: frontera interior, límites naturales, zonas de frontera y frontera norte. En cada caso se presentará una breve contextualización histórica en clave geopolítica. Asimismo, se identificarán sujetos o instituciones que buscaron establecer una determinada definición de esos conceptos de frontera a través de diferentes estrategias narrativas y de visualización. También se reconocerá, muy en general, los usos sociales que tuvieron esos conceptos. Esto permite reconocer la conformación de uno de los componentes principales en la construcción del pensamiento geográfico de la Argentina: las fronteras.This article reviews the emergence and some of the senses granted to four border concepts which were key in the territorial construction of Argentina, and allowed the establishment of some of its geopolitical guidelines at national scale. Those four concepts are: interior border, natural boundaries, border zones and northern border. In each case, a brief historical contextualization is presented in a geopolitical key. Likewise, through different narrative and visualization strategies subjects or institutions that sought to establish a certain definition of these border concepts are identified. Moreover, different social uses of these concepts are stated in broad terms. This allows recognizing the conformation of one of the main components in the construction of the geographic thinking of Argentina: the borders.Este artigo revisará o surgimento e alguns dos sentidos atribuídos a quatro conceitos de fronteira que foram fundamentais na construção territorial da Argentina e que permitiram estabelecer algumas de suas diretrizes geopolíticas para a escala nacional. Esses quatro conceitos são: fronteira interior, limites naturais, zonas de fronteira e fronteira norte. Em cada caso, será apresentada uma breve contextualização histórica em chave geopolítica. Da mesma forma, serão identificados sujeitos ou instituições que buscaram estabelecer alguma definição desses conceitos de fronteira por meio de diferentes estratégias de narrativa e visualização. Além disso serão reconhecidos, em geral, os usos sociais que esses conceitos tiveram. Isso permite reconhecer a conformação de um dos principais componentes na construção do pensamento geográfico da Argentina: as fronteiras.Fil: Benedetti, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Filosofía y Letras. Instituto de Geografía "Romualdo Ardissone"; Argentin

La salteñización del Territorio de Los Andes: Aproximación a la geografía política del noroeste argentino durante la primera mitad del siglo XX

Durante la primera mitad del siglo XX, la Puna de Atacama tuvo para ciertos sectores del noroeste argentino una función geoestratégica para el desarrollo del comercio ganadero interandino, así como un alto valor por su potencial minero. Desde los primeros años de existencia de la jurisdicción del Territorio de Los Andes, la elite terrateniente salteña la transformó en el “patio trasero” de Salta. Este artículo planteará uno de los rasgos salientes sobre la forma en que se incorporó la Puna de Atacama al territorio de la Argentina a partir de 1900: su anexión, en la práctica, a la geografía económica y política de la provincia de Salta. La gravitación salteña es demostrada analizando varios hechos, como el emplazamiento de la capital territoriana, el manejo del aparato institucional por la dirigencia salteña y las decisiones de inversión en infraestructura, todas situaciones que reforzaron la primacía de Salta sobre Los Andes.During the first half of the XX century, the Puna de Atacama had for some sectors of northwestern Argentina, a geostrategic role for the development of inter-Andean livestock trade, well as a high value by its mining potential. Since the early years of jurisdiction of the Territorio de Los Andes, the landed elite of Salta turned it into the "backyard" of the province. This article will present one of the highlights about the way in which the Puna de Atacama was incorporated to the territory of Argentina from 1900: its annexation, in practice, to the economic and political geography of the province of Salta. The gravitation of Salta is shown analyzing several facts, such as the location of the capital of the Territorio, the management of the institutional apparatus by leaders of Salta and infrastructure investment decisions, situations which strengthened the primacy of Salta on Los Andes.Fil: Benedetti, Alejandro. Universidad de Buenos Aires; Argentina. Universidad Nacional de Jujuy; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

LOS ESPACIOS FRONTERIZOS BINACIONALES DEL SUR SUDAMERICANO EN PERSPECTIVA COMPARADA

Artigo convidado para este número