National University of General Sarmiento

El concepto y la experiencia del aburrimiento son centrales en la autoconcepción estética de la vida desarrollada por el pseudónimo A. En este escrito presentamos un análisis del concepto dividiéndolo en tres momentos: en el primero se analiza, desde algunos de los Diapsálmata, la experiencia del aburrimiento como ruptura del vínculo entre hombre y mundo. En el segundo momento, a partir de El más desdichado, se aborda la vivencia del aburrimiento en su relación con el tiempo. Y, en el tercer momento, se indaga, desde el ensayo La rotación de los cultivos, por la respuesta que propone el esteta A como salida al aburrimiento.

A signed graph is one that features two types of edges: positive and negative. Balanced signed graphs are those in which all cycles contain an even number of negative edges. In the adjacency matrix of a signed graph, entries can be 0, -1, or 1, depending on whether ij represents no edge, a negative edge, or a positive edge, respectively. The index of the adjacency matrix of a signed graph G(center dot) is less or equal to the index of the adjacency matrix of its underlying graph G, i.e., lambda(1)( G(center dot))

In epistatic fitness landscapes, the fitness effect of a mutation depends on the genetic background and may even switch between deleterious and beneficial depending on the presence of another mutation. Epistatic interactions may cause both mutations to change the sign of each other's fitness effects (reciprocal sign epistasis) or only one mutation to do so (simple sign epistasis). Both these forms of epistasis influence evolutionary trajectories. While reciprocal sign epistasis has been associated with multi-peaked landscapes and their ruggedness, the role and relative frequency of simple sign epistasis in fitness landscapes have not been systematically investigated. Here, we prove that the presence of simple sign epistasis is associated with evolutionary detours, i.e., indirect, longer fitness-increasing paths to fitness peaks that include back-mutations. We also show that in experimentally resolved, weakly epistatic landscapes, simple sign epistasis occurs much more frequently than reciprocal sign epistasis. This result is consistent with the theoretical predictions we derive for most landscape models, with the exception of the block model and of landscapes dominated by pairwise allelic incompatibilities, such as RNA stability landscapes. Our results suggest that detours represent a general feature of evolutionary trajectories in weakly epistatic landscapes.

A graph is probe diamond-free if its vertex set admits a partition into probes and nonprobes, where the set of nonprobes is independent, such that adding edges only between pairs of nonprobes yields a diamond-free graph. Although this class admits a characterization by forbidden induced subgraphs, such a characterization does not directly lead to an efficient recognition algorithm. In this work we introduce a new structural characterization of probe diamond-free graphs based on a local condition, called the locally union of complete split property, together with an auxiliary bipartite graph. Using this framework, we obtain an O(nm)-time recognition algorithm for (nonpartitioned) probe diamond-free graphs. A distinctive feature of our algorithm is that it is certificate-producing. When the input graph does not belong to the class, the algorithm outputs a negative certificate in the form of a sequence of vertices inducing a minimal forbidden subgraph, ordered according to a fixed degree–lexicographic rule. This ordered representation enables particularly simple and efficient certificate verification. When the input graph is probe diamond-free, the algorithm outputs a positive certificate consisting of a probe partition and a completion set. To the best of our knowledge, this is the first O(nm)-time recognition algorithm for probe diamond-free graphs that produces explicit certificates, providing an alternative to both sandwich-based approaches and exhaustive forbidden subgraph testing.

La Ciudad Autónoma de Buenos Aires, como muchas otras ciudades, desarrolló desde 2009 una extensa red de ciclovías que transformó la circulación urbana y generó debates sobre infraestructura y política. A pesar de la visibilidad del ciclismo urbano en la conversación pública, son pocos los textos literarios que abordaron ese tema de manera significativa. En 2015, Félix Bruzzone, escritor reconocido con el prestigioso premio Anna Seghers, publicó en la revista Crisis la crónica “Peripecias de un ecobicivolador”, basada en su experiencia con el sistema público de bicicletas de la ciudad. A través de recursos característicos de su literatura, como la ironía y la performance, Bruzzone cuestiona los supuestos sobre los que se construyó el sistema de ciclovías. Leída en la actualidad, la crónica permite pensar el ciclismo urbano desde la noción de deriva y examinar las tensiones sociales y políticas entre pasado y presente.