The impact of the American Civil War on city growth

This paper analyzes the persistence of the shock caused by the American Civil War on the relative city size distribution of the United States. Our fi�ndings suggest that the effects of this shock were permanent, which sharply contrasts with previous results regarding World War II for Japanese and German cities. It should be taken into account that the conflict considered in this paper took place at an earlier stage of the industrialization and urbanization processes. Moreover, our results are determined by the fact that the battles were fought in the open �field, not in urban areas. Some related evidence regarding the presence of a safe harbour effect is reported.

Control óptimo sobre estructuras termoconvectivas

En este trabajo consideramos un problema Rayleigh- Bénard 2D y estudiamos el control óptimo de flujos termoconvectivos inducidos por gradientes de temperatura horizontales. El control se ejerce mediante un flujo de calor en la parte superior de la frontera del dominio. Situamos el problema en un marco te´orico en el que se demuestra la existencia de control óptimo y se encuentran las condiciones de optimalidad. Calculamos numéricamente los estados controlados con un método de Chebyshev colocación. El control obtenido elimina las soluciones formadas por uno o varios rollos, es decir, elimina la formación de estructuras no deseables y reduce considerablemente la vorticidad del fluido. Dos rollos, uno sobre otro es el nuevo estado bajo control

On the existence of unbiased resilient estimators in discrete quantum systems

Cram\'er-Rao constitutes a crucial lower bound for the mean squared error of an estimator in frequentist parameter estimation, albeit paradoxically demanding highly accurate prior knowledge of the parameter to be estimated. Indeed, this information is needed to construct the optimal unbiased estimator, which is highly dependent on the parameter. Conversely, Bhattacharyya bounds result in a more resilient estimation about prior accuracy by imposing additional constraints on the estimator. Initially, we conduct a quantitative comparison of the performance between Cram\'er-Rao and Bhattacharyya bounds when faced with less-than-ideal prior knowledge of the parameter. Furthermore, we demonstrate that the $n^{th}$order classical and quantum Bhattacharyya bounds cannot be computed -- given the absence of estimators satisfying the constraints -- under specific conditions tied to the dimension $m$ of the discrete system. Intriguingly, for a system with the same dimension $m$, the maximum non-trivial order $n$ is $m-1$ in the classical case, while in the quantum realm, it extends to $m(m+1)/2-1$. Consequently, for a given system dimension, one can construct estimators in quantum systems that exhibit increased robustness to prior ignorance.Comment: typos corrected and we extended some explanation

The initiation of rotational motion of a lying object caused by wind gusts

In this paper, the initiation of motion of an object lying on a horizontal floor due to the aerodynamic force produced by a time-dependent wind is considered. It is assumed in this paper that when the aerodynamic force is large enough, the body starts to rotate around the most rearward supporting contact point, or pivoting point. This motion is analyzed by studying the dynamics of the rotation of the body around a pivoting point fixed to the floor, and placed in a gravity field under time-dependent aerodynamic loads produced by a non-steady incoming flow. This rotation initiation phase, which is relevant in the case of a time-varying gusty flow, is an intermediate phase between the two stages generally considered, namely, the initial static equilibrium without motion, and the final flight. In this intermediate phase, which is studied here, the rotational dynamics of the body should be taken into account and the gust characteristics as well, in order to determine whether once initiated the motion it leads to either a frustrated motion or to a successful one. A non-linear mathematical model has been developed, and a linear approximation is deduced, which allows us to obtain the condition for a successful flight. This condition shows two limits, valid for either long or short duration gusts, respectively. Some experiments have been performed in a gust wind tunnel, and results show a satisfactory agreement. To take into account the intrinsic random character of the phenomena in practical situations, expressions for the probability of exceeding the condition for successful flight under short duration gusts are obtained, assuming common probability density functions for the random parameters involved

La autoridad cultural de la ciencia en tiempos pandémicos y la postnormalidad cultural en México

Recent national surveys in Mexico show an increase in acceptance of pseudo-scientific beliefs and practices, as well as a negative public perception of the social visibility of scientists. The COVID-19 pandemic has created a post-normal context that allows us to analyse the relevance that Mexican citizens confer upon science and scientists in times of crisis. This paper presents the results of two 2020 studies on public perception of the COVID-19 pandemic, as well as the role of science in fighting it, done on two very different population groups in Mexico: the rural (mostly indigenous) population and the urban population. We compare the results from these studies with other national studies on public understanding of science conducted before the pandemic. In this comparison, we use the indicators Progress, Reserves, Knowledge and Engagement, as recently proposed by Bauer et al., as a way of analysing science’s so-called cultural authority. Our study indicates that in this post-normal sociosanitary situation most citizens, as a general rule, show trust in science and recognize its social legitimacy. Finally, in light of some specific results, we argue that the cultural disparities prevalent in Mexico should be considered especially significant in trying to take advantage of science’s current social prestige in order to improve the social appropriation of scientific culture in Mexico in general, that is, beyond specific post-normal contexts.Las últimas encuestas nacionales en México han mostrado una confianza social creciente en creencias y prácticas pseudocientíficas, así como una percepción pública desfavorable sobre la visibilidad social de los científicos. La situación post-normal generada en la pandemia por COVID-19 se presenta como un escenario propicio para poner a prueba la importancia que los ciudadanos otorgan, de hecho, a la ciencia y sus profesionales en tiempos de crisis. Este artículo ofrece los resultados sobre comprensión pública de la COVID-19 y percepción social sobre el papel de la ciencia en la lucha contra la pandemia obtenidos de dos encuestas realizadas, en 2020, a dos grupos poblacionales de México: población rural, mayoritariamente indígena, y población urbana. Se comparan estos datos con los de otros estudios nacionales sobre comprensión pública de la ciencia (PUS en sus siglas en inglés) prepandémicos haciendo uso de los indicadores Progreso, Reticencias, Conocimiento y Compromiso (PREK en sus siglas en inglés), propuestos recientemente por Martin Bauer y colaboradores para valorar la llamada autoridad cultural de la ciencia. Nuestra investigación muestra la confianza y legitimidad sociales otorgadas, en general, a la ciencia en esta situación socio-sanitaria post-normal. Finalmente, a la luz de ciertos resultados, defendemos que las disparidades culturales propias de México se desvelan significativas a la hora de considerar el aprovechar tal prestigio social en el logro de un incremento de la apropiación social de cultura científica en México en general, es decir, más allá de contextos post-normales concretos

Soy grande, contengo multitudes. Pragmatismo epistémico, injusticia testimonial e interseccionalismo positivo

We explore the compatibilities and incompatibilities between two highly successful approaches to knowledge: Brandom’s epistemic pragmatism, [EP], and the view that derives from Fricker’s seminal work on the ethics of knowing, [EK]. [EP] and [EK] are complementary approaches that put forward aspects of the application of the concept that deserve to be preserved. Nevertheless, their mere cumulative superposition produces dysfunctions that call for certain readjustments. We propose a positive kind of intersectionalism, [PI], that accounts for the fact that individuals simultaneously belong to diverse groups with variable epistemic conditions, some advantageous, some disadvantageous. [EP], [EK] and [PI] make a rich and coherent picture of subjects as full epistemic agents.En este trabajo exploramos las compatibilidades e incompatibilidades entre dos enfoques del conocimiento distintos y de gran éxito. El primero es el análisis del conocimiento que ofrece el pragmatismo epistémico de Brandom [PE]. El segundo es el punto de vista que se deriva de la obra seminal de Fricker sobre la ética del conocimiento [EC]. [PE] y [EC] plantean concepciones complementarias de la aplicación del concepto de conocimiento que merecen preservarse. Sin embargo, su mera superposición acumulativa produce disfunciones que exigen ciertos reajustes. Proponemos un tipo de interseccionalismo positivo, [IP], que da cuenta del hecho de que los individuos pertenecen simultáneamente a diversos grupos con condiciones epistémicas variables, algunas ventajosas y otras desventajosas. [EP], [EK] y [PI] conforman un cuadro rico y coherente sobre los sujetos como agentes epistémicos plenos

The impact of the American Civil War on city growth

This paper analyzes the persistence of the shock caused by the American Civil War on the relative city size distribution of the United States. Our fi ndings suggest that the effects of this shock were permanent, which sharply contrasts with previous results regarding World War II for Japanese and German cities. It should be taken into account that the conflict considered in this paper took place at an earlier stage of the industrialization and urbanization processes. Moreover, our results are determined by the fact that the battles were fought in the open field, not in urban areas. Some related evidence regarding the presence of a safe harbour effect is reported