An Alternative Approach to the Calculation and Analysis of Connectivity in the World City Network

Empirical research on world cities often draws on Taylor's (2001) notion of an 'interlocking network model', in which office networks of globalized service firms are assumed to shape the spatialities of urban networks. In spite of its many merits, this approach is limited because the resultant adjacency matrices are not really fit for network-analytic calculations. We therefore propose a fresh analytical approach using a primary linkage algorithm that produces a one-mode directed graph based on Taylor's two-mode city/firm network data. The procedure has the advantage of creating less dense networks when compared to the interlocking network model, while nonetheless retaining the network structure apparent in the initial dataset. We randomize the empirical network with a bootstrapping simulation approach, and compare the simulated parameters of this null-model with our empirical network parameter (i.e. betweenness centrality). We find that our approach produces results that are comparable to those of the standard interlocking network model. However, because our approach is based on an actual graph representation and network analysis, we are able to assess cities' position in the network at large. For instance, we find that cities such as Tokyo, Sydney, Melbourne, Almaty and Karachi hold more strategic and valuable positions than suggested in the interlocking networks as they play a bridging role in connecting cities across regions. In general, we argue that our graph representation allows for further and deeper analysis of the original data, further extending world city network research into a theory-based empirical research approach.Comment: 18 pages, 9 figures, 2 table

Urban Resilience Discourse Analysis: Towards a Multi-Level Approach to Cities

This study aims to understand the current state of research in urban resilience, its relations to urban sustainability and to integrate several distinct approaches into a multi-level perspective of cities comprising micro, meso and macro levels and their interactions. In fact, based on the meta-analysis of nearly 800 papers from Scopus from 1973 to 2018, we show that urban resilience discourses address micro and meso levels, considering shocks of bottom-up origin such as natural disasters. In contrast, the regional resilience approach addresses meso and macro levels (regional and global scales), considering shocks of top-down origin such as world economic crises. We find these approaches complementary and argue that in order to expand the urban resilience theory and overcome its limitations, they should be combined. For that purpose we propose a multi-level perspective that integrates both top-down and bottom-up dynamic processes. We argue that urban resilience is shaped by the synchronicity of adaptive cycles on three levels: micro, meso and macro. To build the multi-level approach of dynamics of adaptive cycles we use the panarchy framework

Equations over free inverse monoids with idempotent variables

We introduce the notion of idempotent variables for studying equations in inverse monoids. It is proved that it is decidable in singly exponential time (DEXPTIME) whether a system of equations in idempotent variables over a free inverse monoid has a solution. The result is proved by a direct reduction to solve language equations with one-sided concatenation and a known complexity result by Baader and Narendran: Unification of concept terms in description logics, 2001. We also show that the problem becomes DEXPTIME hard , as soon as the quotient group of the free inverse monoid has rank at least two. Decidability for systems of typed equations over a free inverse monoid with one irreducible variable and at least one unbalanced equation is proved with the same complexity for the upper bound. Our results improve known complexity bounds by Deis, Meakin, and Senizergues: Equations in free inverse monoids, 2007. Our results also apply to larger families of equations where no decidability has been previously known.Comment: 28 pages. The conference version of this paper appeared in the proceedings of 10th International Computer Science Symposium in Russia, CSR 2015, Listvyanka, Russia, July 13-17, 2015. Springer LNCS 9139, pp. 173-188 (2015

Worldwide spreading of economic crisis

We model the spreading of a crisis by constructing a global economic network and applying the Susceptible-Infected-Recovered (SIR) epidemic model with a variable probability of infection. The probability of infection depends on the strength of economic relations between the pair of countries, and the strength of the target country. It is expected that a crisis which originates in a large country, such as the USA, has the potential to spread globally, like the recent crisis. Surprisingly we show that also countries with much lower GDP, such as Belgium, are able to initiate a global crisis. Using the {\it k}-shell decomposition method to quantify the spreading power (of a node), we obtain a measure of ``centrality'' as a spreader of each country in the economic network. We thus rank the different countries according to the shell they belong to, and find the 12 most central countries. These countries are the most likely to spread a crisis globally. Of these 12 only six are large economies, while the other six are medium/small ones, a result that could not have been otherwise anticipated. Furthermore, we use our model to predict the crisis spreading potential of countries belonging to different shells according to the crisis magnitude.Comment: 13 pages, 4 figures and Supplementary Materia

Estudio longitudinal de lesiones deportivas en practicantes de gimnasia aeróbica de competición

Introduction: Aerobic gymnastics, since its membership in the International Gymnastics Federation, has undergone changes in its regulations. Objective: To analyze the injuries found in Spanish aerobic gymnastics athletes during different editions of the Code of Points. Methods: A descriptive, longitudinal and compara-tive study was carried out on the epidemiology of injuries in aerobic gymnastics published during different editions of the Code of Points. Results: It highlights that the number of injuries decreased from 156 to 38 last year. This decline has been related to the restriction on the number of difficulties in the exercise and the number of elements to be performed on the floor. However, they have increased the number and value of the difficulties. Conclusions: Therefore, it is concluded that the changes made in the regulations are intended to safeguard the health of athletes and ensure that competition develops at its best artistic and technical aspect.Introdução: A ginástica aeróbica, desde sua adesão à Federação Internacional de Ginástica, passou por mudanças em seus regulamentos. Objetivo: Analisar as lesões encontradas nos atletas espanhóis de ginástica aeróbica durante as diferentes edições do Código de Pontos. Métodos: Realizou-se um estudo descritivo, longitudinal e comparativo sobre a epidemiologia de lesões na ginástica aeróbica publicado durante as diferentes edições do Código de Pontos. Resultados Salienta-se que o número de lesões diminuiu de 156 para 38 no ano passado. Este declínio tem sido relacionado com a limitação do número de dificuldades no exercício e o número de elementos a serem feitos no solo. No entanto, eles aumentaram o número e valor das dificuldades. Conclusões: Portanto, concluiu-se que as modificações feitas nos regulamentos destinam-se a salvaguardar a saúde dos atletas e garantir que a competição se desenvolva no seu melhor aspecto artístico e técnico.Introducción: La gimnasia aeróbica desde su pertenencia a la Federación Internacional de Gimnasia ha sufrido cam-bios en su reglamentación. Objetivo: Analizar las lesiones que los deportistas españoles de gimnasia aeróbica presentaron durante las diferentes ediciones del Código de Puntuación. Métodos: Se ha realizado un estudio descriptivo, longitudinal y comparativo sobre la epidemiología de las lesiones en la gimnasia aeróbica publicado durante las diferentes ediciones del Código de Puntuación. Resultados: El estudio destaca la disminución del número de lesiones, de 156 a 38 en el último año. Esta disminución ha tenido relación con la restricción del número de dificultades en el ejercicio y la cantidad de elementos a realizar en el suelo. Sin embargo, han aumentado el número y el valor de las dificultades. Conclusiones: Por tanto, han concluido que las modificaciones que se realizan en la reglamentación tienen como objetivo velar por la salud de los deportistas y garantizar que la competición se desarrolle en su máximo esplendor artístico y técnico

Bullous pemphigoid and neurological disorders among a Jewish population

A retrospective case control study included data regarding 65 Jewish bullous pemphigoid (BP) patients diagnosed in a tertiary medical center and a control group consisting of 182 matched Jewish patients. The study indicates that Jewish patients with BP suffer from a higher prevalence of neurological diseases compared to patients with no BP, similarly to previous reports showing high prevalence of neurological diseases among BP patients from different ethnic groups