The fluid mechanics of bubbly drinks

Bubbly drinks are surprisingly attractive. There is something about the nature of the these beverages that make them preferable among other choices. In this article we explore the physics involved in this particular kind of two-phase, mass-transfer-driven flows.Comment: Extended version of Zenit R and Rodr\'iguez-Rodr\'iguez J. The fluid mechanics of bubbly drinks. Physics Today, Vol. 71(11) pp. 44-50, November 201

Banking on Democracy: The Political Economy of International Private Bank Lending in Emerging Markets

Clearly, a new agenda is emerging for private international banks. Political issues such as human rights seem to be a current concern. But what about democracy? What about political regimes? Are they taken into account by private banks when they decide whether to invest in a country? Put another way, do private banks have democratic political preferences? In this article, we focus on cross-border lending from international bank(er)s. The questions asked are as follows. Do bank(er)s react positively (that is by increasing their lending) when an emerging democracy appears? Do we witness increased bank lending after democratic transitions? Lastly, is there any relation between democratic consolidation and bank lending?Banks;Capital flows;Democracy;Emerging markets

Estimation of the modulation index of cpm signals using hos

Three simple methods are proposed for the estimation of the modulation index of continuous phase modulated signals in noise. These methods employ the estimated autocorrelation and fourth-order cumulant sequences of the received signal after sampling at the symbol rate. Analytic expressions are derived for the asymptotic mean and variance of the estimated parameters which are corroborated by means of Monte Carlo simulations. The performance of the methods is illustrated graphically and numerically. It is concluded that, under significant noise degradation, only the scheme based on the fourth-order cumulant sequence can be used to estimate consistently the modulation index h in the range 0(h(1.Peer ReviewedPostprint (published version

Downlink beamforming for cellular mobile communications

A new technique for downlink transmission beamformer design in cellular mobile communications systems using an antenna array at the base station is presented. The method is based on estimation of an underlying spatial distribution associated with each source's spatial downlink channel. The algorithm isPeer ReviewedPostprint (published version

Causes and success of brand deletions. The role of brand orientation

La eliminación de una marca es una decisión crítica dentro de la estrategia de marketing de una empresa. Pese a que en los últimos años muchas organizaciones han tomado este tipo de decisión y han acometido drásticos programas de eliminación de marcas, la literatura sobre este tema es muy escasa y fragmentada, y son múltiples las cuestiones que se deben abordar. Concretamente, en este trabajo nos proponemos examinar la influencia de las causas de eliminación de una marca –previamente clasificadas en proactivas y reactivas– en el éxito de la decisión. Además, exploramos el efecto que la orientación a la marca tiene en la mayor o menor ocurrencia de eliminaciones por causas proactivas o reactivas. Implícitamente, en el trabajo proponemos que la orientación a la marca tendrá un doble efecto indirecto positivo en el éxito de una eliminación. En primer lugar, a través de incremento de eliminaciones exitosas que ocurren por causas proactivas y, en segundo, por la reducción de eliminaciones no exitosas que sobrevienen por causas reactivas. La propuesta investigadora que realizamos se testa sobre una muestra de 155 casos de eliminación de marca. Los análisis preliminares indican que la orientación a la marca contribuye al éxito a través de la adopción de eliminaciones enfocadas en el aprovechamiento de oportunidades de la marca, tales como un mayor ajuste estratégico o unos menores costes de oportunidad. Además, la orientación a la marca previene de realizar eliminaciones simplemente por causas problemáticas, eliminaciones que no acaban arrojando grandes resultados.Brand deletion (BD) is a critical decision within a firm’s marketing strategy. Despite in recent years many organizations have pruned their brand portfolios and undertaken drastic BD programs, the literature on this topic is extremely scarce and fragmented, and several issues of BD can be investigated. This research is primarily concerned with the study of the impact of BD causes –previously classified as proactive versus reactive– on BD success. In addition, we explore the effect of the firm’s brand orientation on the occurrence of deletions by proactive versus reactive causes. Implicitly, we suggest that brand orientation will have a double positive indirect effect on BD success: first, through the increase of successful BDs due to proactive causes and, second, by the reduction of unsuccessful BDs precipitated by reactive causes. Our research proposal is tested on a sample of 155 cases of BD. Preliminary findings indicate that brand orientation contributes to the BD success through the adoption of BDs focused on taking advantage of brand opportunities, such as searching for a better strategic fit or avoiding opportunity costs. Besides, brand orientation prevents deletions due to merely problematic causes, deletions that, after all, do not generate success

Factors that explain the use of ICT in secondary-education classrooms: the role of teacher characteristics and school infrastructure

Paradoxically, in Spain, schools have relatively ample information and communication technology (ICT)infrastructure but low levels of classroom ICT use. In this study, we analyse the role of school ICTinfrastructure and teacher characteristics to explain ICT use in education. We use data from the Spanishsample in the 2013 Teaching and Learning International Study (TALIS), which consists of 3339 teachersfrom 192 secondary education centres. The analysis was conducted using multilevel logistic regressionmodels. The principal results indicate that the availability of educational software, teacher ICT training,collaboration among teachers, perceived self-efficacy, and teaching concepts influence classroom ICT use.School hardware and internet-connection infrastructure are less significant. Based on thefindings,recommendations are presented to orient Spanish educational policy to encourage the use of ICT in classroom

Blind multiuser detection using hidden markov models theory

We present an adaptive algorithm based on the theory of hidden Markov models (HMM) which is capable of jointly detecting the users in a DS-CDMA system. The proposed technique is near-far resistant and completely blind in the sense that no knowledge of the signature sequences, channel state information or training sequences is required for any user. In addition to this, an estimate of the signature of each user convolved with its physical channel impulse response (CIR), and an estimate of the background noise variance are provided once convergence is achieved (as well as estimated data sequences). At this moment, and using that CIR estimate, we can switch to any decision-directed (DD) adaptation scheme.Peer ReviewedPostprint (published version

Array joint detection for C/TDMA systems in UMTS environments

Two array-based schemes for intracell and intercell interference suppression are proposed. In both cases, the spatial and temporal characteristics of the propagation are jointly exploited by placing a narrowband beamformer prior to the corresponding data detection stage. In the first approach, the filtered training sequence joint detection receiver (FTS-JDR), the beamformer is devoted to exclusively cancel out intercell interference. This way, intracell users can be jointly detected in a MMSE detection block. In contrast, the second algorithm, known as the filtered training sequence multisensor receiver (FTS-MR), aims to attenuate all the interferers in the beamforming stage which allows the user of interest to be detected following a MLSE strategy. In order to assess the performance of the proposed schemes, a set of link-level computer simulations adopting FRAMES' proposal for UMTS air-interface as well as realistic channel models for third generation communication systems is provided. Simulation results indicate that lower BERs can be obtained by concentrating interference cancellation tasks in the beamforming block.Peer ReviewedPostprint (published version