The Berry phase and the pump flux in stochastic chemical kinetics

We study a classical two-state stochastic system in a sea of substrates and products (absorbing states), which can be interpreted as a single Michaelis-Menten catalyzing enzyme or as a channel on a cell surface. We introduce a novel general method and use it to derive the expression for the full counting statistics of transitions among the absorbing states. For the evolution of the system under a periodic perturbation of the kinetic rates, the latter contains a term with a purely geometrical (the Berry phase) interpretation. This term gives rise to a pump current between the absorbing states, which is due entirely to the stochastic nature of the system. We calculate the first two cumulants of this current, and we argue that it is observable experimentally

El espectáculo religioso barroco

Ofrece el autor en este articulo una serie de reflexiones metodológicas sobre el tema de la fiesta barroca tal como lo estudia la historia social, con la intención de descartar interpretaciones reduccionistas. Establece una "mínima taxonomía elemental" de la fiesta, distinguiendo tres tipos básicos y, finaliza, señalando las carcaterísticas de la fiesta barroca, en tanto que puede concebirse como metáfora, las cuales explican su éxito en la época.Though this article the author, rejecting the reductionist interpretations, makes some methodological reflections un the baroque public festivities as they were studied by social history. Alvárez Santaló establishes a "minimum elemental taxonomy" of those festivities distinguishing among them three basic types of fiesta and he finishes his script indicating the main traits of a baroque rejoicing, conceived as a metaphor, which explain its success in that period

Proceso de heroificación

Ignacio Sánchez Mejías. Periodista y dramaturgo. Seminari

Analysis of consequences of the measures of adaptation to climate variability and change of current storm sewer of Chapinero - Bogotá

En el presente artículo se realiza un análisis de las medidas de adaptación a la variabilidad y cambio climático dadas por el Plan Regional Integral de Cambio Climático de Bogotá – Cundinamarca (PRICC), para el alcantarillado pluvial actual en la localidad de Chapinero - Bogotá, debido a que en este sector se han presentado grandes problemas de inundación y encharcamiento por mal manejo de las aguas lluvias, lo que ha causado inconvenientes en los habitantes de la ciudad. Se da a conocer las diferentes consecuencias pasadas y presentes de los escenarios de encharcamiento que se producen en este sector, debido a que el sistema de alcantarillado pluvial actual no cuenta con las medidas adecuadas que se deben desarrollar e implementar para afrontar los efectos que pueden ocasionar la variabilidad y cambio climático. Por último, se dan a conocer las condiciones actuales del alcantarillado pluvial de Bogotá y las acciones que ha desarrollado el gobierno para poder mitigar los efectos que trae la variabilidad y cambio climático para la ciudad.In the present article an analysis of the adaptation measures to the variability and climate change given by the Integral Regional Plan of Climatic Change of Bogotá - Cundinamarca (PRICC), will be carried out, for the current pluvial sewage system in the locality of Chapinero - Bogotá, because in this sector have presented great problems of floods and flooding by mismanagement of rainwater, which has caused inconveniences in the habitants of the city. It is also intended to make known the different past and present consequences of the flooding scenarios occurring in this sector, because the current storm drainage system does not have the appropriate measures that must be developed and implemented face the effects which can cause variability and climate change. Finally, the current conditions of Bogotá's sewage system and the actions developed by the government are presented to mitigate the effects of climate variability and change for the city

Classifying spaces for families of abelian subgroups of braid groups, RAAGs and graphs of abelian groups

Given a group $G$ and an integer $n\geq 0$ we consider the family $\mathcal{F}_n$ of all virtually abelian subgroups of $G$ of rank at most $n$. In this article we prove that for each $n\ge2$ the Bredon cohomology, with respect to the family $\mathcal{F}_n$, of a free abelian group with rank $k > n$ is nontrivial in dimension $k+n$; this answers a question of Corob Cook, Moreno, Nucinkis and Pasini. As an application, we compute the minimal dimension of a classifying space for the family $\mathcal{F}_n$ for braid groups, right-angled Artin groups, and graphs of groups whose vertex groups are infinite finitely generated virtually abelian groups, for all $n\ge2$. The main tools that we use are the Mayer-Vietoris sequence for Bredon cohomology, Bass-Serre theory, and the L\"uck-Weiermann construction.Comment: 17 pages, 1 figur

El comercio digital y la transformación regional de la economía de América del Norte

North American Free Trade Agreement (NAFTA) was a cornerstone of the 1990s liberal hegemony established with the rise of multilateral trade agreements. On July 1st 2020, NAFTA was replaced by a new trade deal: USMCA (United States-Mexico-Canada Agreement). This article argues that through the inclusion of digital trade provisions, USMCA signifies a vision of a regional economic space that differs substantively from NAFTA’s. To make this case, the article examines the digital trade provisions in USMCA, contrasts them with the vision of trade advanced by NAFTA, and evaluates how they create conditions that can transform the North American space-economy.El Tratado del Libre Comercio de América del Norte (TLCAN, NAFTA en inglés) cimentó la hegemonía liberal que ascendió con los tratados multilaterales en los 1990s. El 1º de julio de 2020 el TLC fue remplazado por el nuevo Tratado entre México, Estados Unidos y Canadá (T-MEC, USMCA en inglés). Este artículo argumenta que, al incluir el comercio digital, el T-MEC significa una transformación en la visión del espacio económico regional. El artículo examina las provisiones de comercio digital en el T-MEC, contrastándolas con el TLCAN, y evalúa las condiciones de cambio en el espacio económico de América del Norte

Recensions

Obra ressenyada: Mercedes VILANOVA, Las mayorías invisibles. Explotación fabril, revolución y represión. Barcelona: Icaria, 1996

Recensions

Obra ressenyada: Pierre BORDIEU, La domination masculine. París: Seuil, 1998

Planarian (Platyhelminthes, Tricladida) Diversity and Molecular Markers: A New View of an Old Group

Planarians are a group of free-living platyhelminths (triclads) best-known largely due to long-standing regeneration and pattern formation research. However, the group"s diversity and evolutionary history has been mostly overlooked. A few taxonomists have focused on certain groups, resulting in the description of many species and the establishment of higher-level groups within the Tricladida. However, the scarcity of morphological features precludes inference of phylogenetic relationships among these taxa. The incorporation of molecular markers to study their diversity and phylogenetic relationships has facilitated disentangling many conundrums related to planarians and even allowed their use as phylogeographic model organisms. Here, we present some case examples ranging from delimiting species in an integrative style, and barcoding them, to analysing their evolutionary history on a lower scale to infer processes affecting biodiversity origin, or on a higher scale to understand the genus level or even higher relationships. In many cases, these studies have allowed proposing better classifications and resulted in taxonomical changes. We also explain shortcomings resulting in a lack of resolution or power to apply the most up-to-date data analyses. Next-generation sequencing methodologies may help improve this situation and accelerate their use as model organisms