El valor agregado de las redes sociales: propuesta metodológica para el análisis del capital social

En el presente trabajo se utiliza una variable reticular para estratificar un grupo de actores sociales, lo cual permite exhibir la posición estructural de sus integrantes en base al origen de su capital social. Se utiliza la variable constricción debido a que integra en una sola medida las dos fuentes principales de capital social: cierre e intermediación. Este enfoque, permite generar hipótesis inmediatas sobre los mecanismos subyacentes a la Posición estructural que actualmente posee cada individuo; sobre las razones por las cuales unos individuos son más exitosos que otros (recursos sociales) y, sobre las acciones posibles para generar efectos agregados que generen valor en la red general

Función y sentido de los espacios de la corte en Tirant lo Blanch: aposentos privados, salas de consejo, huertos y espacios públicos del palacio

En un artículo previo (Velázquez 2007), argumentaba que un análisis de la función y el sentido de los espacios en Tirant lo Blanch permitiría brindar una explicación sobre la caracterización y el desarrollo heroico anómalos que presentaba elprotagonista respecto de otras obras de género caballeresco. Dicho estudio estuvo basado en la propuesta teórica de Campos García Rojas (2002), y su propósito fue examinar la relación existente entre los espacios exteriores y el desarrollo heroico que se daba en dichos lugares. Este artículo aborda la problemática antedicha, enfocándose en la corte y sus espacios. Establezco un análisis funcional de los aposentos privados,las salas de consejo, los huertos y los espacios del palacio y considero la relación que existe entre las acciones que ahí tienen lugar y su impacto en la conformación de Tirant.Asimismo, sostengo que los cambios de la visión del mundo en ese momento histórico tienen un correlato en el texto martorelliano. Tirant es un personaje que refleja dicha situación

Venezuela’s case

The resource curse literature’s main lesson is that developing and natural resourcerich countries should save most of their oil windfalls in foreign currency. Moreover, the political cycle literature’s recent contributions predict stronger cycles in these countries. This paper investigates how political cycles might explain low oil windfall savings. Using Venezuela’s case, the paper argues that power concentration during periods of oil price explosiveness leads to increased public investment in prestige projects aimed at increasing the incumbent’s – or his party’s – re-election probabilities. The article backs the argument analyzing the Chavista democratic period of 1999- 2016. It also identifies parallels with Venezuela’s 1970-1988 period

Growth Impacts of the Exchange Rate and Technology

The aim of this paper is to assess whether the impacts of real exchange rate undervaluation and domestic technological capabilities on growth are stable across development levels. On the one hand, a real exchange undervaluation measure is constructed based on the purchasing-power-parity theory corrected by the Balassa-Samuelson effect. On the other hand, the index of technological specialization is used as a measure of domestic technological capabilities. Time-series-cross-section-growth regressions with development level interactions are used to test the stability of these variables’ growth impact. The results show that real undervaluation is a growth driver across all development levels, once technological capabilities are accounted for; however, it is more important for developing and developed countries than for emerging markets. The results also suggest that developing countries grow faster when they are globally competitive in low-technology manufacturing and natural-resource-intensive industries. This research attempts to explain the lack of significance found in previous studies of the growth impact of real undervaluation in middle-income countries by accounting for an explicit role for domestic technological capabilities in the development process

The k-metric dimension of a graph

As a generalization of the concept of a metric basis, this article introduces the notion of $k$-metric basis in graphs. Given a connected graph $G=(V,E)$, a set $S\subseteq V$ is said to be a $k$-metric generator for $G$ if the elements of any pair of different vertices of $G$ are distinguished by at least $k$ elements of $S$, i.e., for any two different vertices $u,v\in V$, there exist at least $k$ vertices $w_1,w_2,...,w_k\in S$ such that $d_G(u,w_i)\ne d_G(v,w_i)$ for every $i\in \{1,...,k\}$. A metric generator of minimum cardinality is called a $k$-metric basis and its cardinality the $k$-metric dimension of $G$. A connected graph $G$ is $k$-metric dimensional if $k$ is the largest integer such that there exists a $k$-metric basis for $G$. We give a necessary and sufficient condition for a graph to be $k$-metric dimensional and we obtain several results on the $k$-metric dimension

Investigating the cross-disciplinary components of earthquake early warning systems

Earthquake early warning (EEW) systems typically provide early estimates of earthquake magnitude, hypocentre location and/or ground-shaking estimates, as well as alerts ranging from a few seconds to tens of seconds, before the arrival of the damaging ground shaking at a target site. The warnings provided by these systems allow for the implementation of fast protection actions carried out by individuals like ‘drop, cover, and hold-on’, or the evacuation of buildings if the lead time is long enough. Nevertheless, the information and warning time provided by an EEW system could also be used by earthquake engineers as EEW seems to bear a powerful potential for the automatic activation of protection measures for infrastructure and critical systems, aiming at the reduction of risk due to earthquakes. Such automatic actions may include stopping elevators at the nearest floor, opening firehouse doors, slowing rapid-transit vehicles and high-speed trains to avoid accidents, to mention some. Few are the attempts found in literature about engineering applicability of EEW. This scarcity might be related to the fact that the real-time estimation of earthquake source parameters contains considerable uncertainty that may lead to potential economic losses if false or missed alarms are not avoided. However, different state-of-the-art studies regarding decision-making procedures for EEW have suggested more reliable approaches that can potentially reduce the uncertainty in the estimates provided by the system (e.g., earthquake source parameters and ground shaking), reducing the probability of triggering missed/false alarms, and therefore minimising the expected losses. The potential of designing new real-time advanced building protection applications for EEW is the motivation of this thesis. Mainly, two applications are considered: 1) Design of controlled structural systems using the early warning information, particularly, the use of semi-active devices denominated magnetorheological dampers. A control algorithm that governs the behaviour of the dampers is calibrated to obtain the most favourable response of a benchmark structure equipped with one damper. The results reveal that the developed EEW-based control algorithm can effectively reduce the expected loss of the considered case-study structure. 2) Prediction of shaking demands that can be expected in mid-rise to high-rise buildings, using a simplified continuum building model. A series of illustrative examples show how the newly developed prediction models can be efficiently used, in a Bayesian framework, for building-specific EEW applications based on the (acceleration) response in buildings, such as a) early warning of floor-shaking sensed by occupants; and b) control of elevator in buildings. The progress of technology and advances in the scientific understanding of engineering and seismology have promoted the rapid development of EEW systems around the world. However, their effectiveness is often limited as they lack the integration between their technical and social components. This thesis also aims at filling this gap to investigate which measures could be needed to increase the organisational resilience of local community stakeholders and the private sector. This topic is explored by implementing a mixed-method approach on the case study Mexico City (Mexico), that can be considered an area at risk due to the combination of high seismic hazard, structural and social vulnerabilities. This thesis shows the promising applicability of engineered applications of EEW systems and suggests a robust framework for the integration of the technical and societal components of EEW

Quantum chaos and nuclear mass systematics

The presence of quantum chaos in nuclear mass systematics is analyzed by considering the differences between measured and calculated nuclear masses as a time series described by the power law 1/ f^alpha. While for the liquid droplet model plus shell corrections a quantum chaotic behavior alpha approx 1 is found, errors in the microscopic mass formula have alpha approx 0.5, closer to white noise. The chaotic behavior seems to arise from many body effects not included in the mass formula.Comment: 4 pages, 6 figures, replaced to match the published versio