96 research outputs found
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
Urban Systems Between National and Global: Recent Reconfiguration Through Transnational Networks
Because the whole book’s issue assumes the uneven integrations of national/continental urban systems inside the global economy, this chapter evaluates the rates and qualitative modes of integration of the national urban systems by
the economic networks that are dominated by multinational firms. The empirical study encompasses the largest 1250 cities of the world delineated in a comparative way according to common definitions of large urban regions (LURs). The position of LURs in multinational firms’ ownership networks in 2 years, 2010 and 2013, corresponds to the deepest period of the crisis and the following recovery, respectively. Thus, we checked that the fast reorganization of multinational firms facing this crisis between 2010 and 2013 did not fundamentally transform their strong urban organization but rather introduced some minor changes, particularly due to the simultaneous breakthrough of emergent countries’ companies (especially the Chinese ones). Synthetic network clustering methods partitioning cities of the world offer clear visions of the structure of the multipolar urban networks. They reveal “regions” of integration of cities for all kinds of multinational companies but also distinguishing companies according to their skill levels either in industry or in services. A special attention is given to some highly integrated cities appearing with properties of “city-states,” i.e., without a strong national urban system
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
A systematic review and secondary data analysis of the interactions between the serotonin transporter 5-HTTLPR polymorphism and environmental and psychological factors in eating disorders
Objectives: to summarize and synthesize the growing gene x environment (GxE) research investigating the promoter region of the serotonin transporter gene (5-HTTLPR) in the eating disorders (ED) field, and overcome the common limitation of low sample size, by undertaking a systematic review followed by a secondary data meta-analysis of studies identified by the review. Method: a systematic review of articles using PsycINFO, PubMed, and EMBASE was undertaken to identify studies investigating the interaction between 5-HTTLPR and an environmental or psychological factor, with an ED-related outcome variable. Seven studies were identified by the systematic review, with complete data sets of five community (n = 1750, 64.5% female) and two clinical (n = 426,100% female) samples combined to perform four secondary-data analyses: 5-I-M1PR x Traumatic Life Events to predict ED status (n = 909), 5-HTTLPR x Sexual and Physical Abuse to predict bulimic symptoms (n = 1097), 5-HTTLPR x Depression to predict bulimic symptoms (n = 1256), and 5-HTTLPRx Impulsiveness to predict disordered eating (n = 1149). Results: under a multiplicative model, the low function (s) allele of 5-HTTLPR interacted with traumatic life events and experiencing both sexual and physical abuse (but not only one) to predict increased likelihood of an ED and bulimic symptoms, respectively. However, under an additive model there was also an interaction between sexual and physical abuse considered independently and 5-HTTLPR, and no interaction with traumatic life events. No other GxE interactions were significant. Conclusion: early promising results should be followed-up with continued cross-institutional collaboration in order to achieve the large sample sizes necessary for genetic research
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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
Recommended from our members
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
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