Coherence effects in disordered geometries with a field-theory dual

We investigate the holographic dual of a probe scalar in an asymptotically Anti-de-Sitter (AdS) disordered background which is an exact solution of Einstein's equations in three bulk dimensions. Unlike other approaches to model disorder in holography, we are able to explore quantum wave-like interference effects between an oscillating or random source and the geometry. In the weak-disorder limit, we compute analytically and numerically the one-point correlation function of the dual field theory for different choices of sources and backgrounds. The most interesting feature is the suppression of the one-point function in the presence of an oscillating source and weak random background. We have also computed analytically and numerically the two-point function in the weak disorder limit. We have found that, in general, the perturbative contribution induces an additional power-law decay whose exponent depends on the distribution of disorder. For certain choices of the gravity background, this contribution becomes dominant for large separations which indicates breaking of perturbation theory and the possible existence of a phase transition induced by disorder.Comment: 36 pages, 19 figs, v3 accepted versio

Mapping the Americanization of English in Space and Time

As global political preeminence gradually shifted from the United Kingdom to the United States, so did the capacity to culturally influence the rest of the world. In this work, we analyze how the world-wide varieties of written English are evolving. We study both the spatial and temporal variations of vocabulary and spelling of English using a large corpus of geolocated tweets and the Google Books datasets corresponding to books published in the US and the UK. The advantage of our approach is that we can address both standard written language (Google Books) and the more colloquial forms of microblogging messages (Twitter). We find that American English is the dominant form of English outside the UK and that its influence is felt even within the UK borders. Finally, we analyze how this trend has evolved over time and the impact that some cultural events have had in shaping it.Comment: 16 pages, 6 figures, 2 tables. Published versio

The impact of streaming services and video-on-demand on the cinematic exhibition industry: taking an experiential approach

Streaming services and video-on-demand completely reshaped the cinematic industry, as people now have more convenient alternatives to the traditional movie-going experience. One can say that audiences have fallen out of love and are now disengaged with movie theatres. As such, movie exhibitors are losing business all over the world, including in Portugal, and they need to reimagine themselves. With this in mind, this dissertation will start off by reviewing topics such as brand love and engagement. Both of these are recognized to foster customer satisfaction and loyalty. One of the most interesting conclusions is that both appear to be deeply embedded in brand experiences and co-created value. Thusly, the following topic will revolve around brand experiences and how experiential marketing enhances the interactions and the relationship between consumers and brands. Lastly, this dissertation will attempt to understand if experiential practices are a good fit to the cinematic exhibition industry, and if they have the potential to take Portuguese viewers back to movie theatres. To do this, primary research was conducted where respondents were presented with an experiential scenario to complement their typical movie-going experience. This study provides some interesting ones, along with important insights for the cinematic industry in Portugal. The participants responded overwhelmingly positive to the experiential scenarios, which enhance the brand experience overall. Regarding behavioural intentions and commitment, the results were also encouraging, with respondents feeling like these scenarios would increase their connection to the brand and they would encourage them to be more frequent moviegoers.Os serviços de streaming e de video-on-demand reformularam por completo a indústria cinemática, uma vez que oferecem uma alternativa mais conveniente à tradicional ida ao cinema. Como tal, os exibidores de cinema em todo mundo têm perdido cada vez mais terreno, e Portugal não é exceção, necessitando de se reinventar rapidamente. Com isto em mente, esta dissertação irá começar por analisar tópicos como brand love e brand engagement. Ambos são academicamente reconhecidos por gerar elevados níveis de satisfação e lealdade nos consumidores. Umas das mais importantes ilações é que ambos aparecem frequentemente associados a experiências de marca e valor co-criado. Portanto, o seguinte tópico irá incidir sobre o tema de experiências de marca e a maneira como estas abordagens promovem melhor relação entre consumidores e marca. Por fim, esta dissertação irá procurar perceber se práticas experienciais poderão ser aplicadas na indústria, se têm o potencial para devolver os Portugueses às salas de cinema. Para tal, foi levada a cabo um estudo onde foi apresentado um cenário experiencial aos respondentes, cenário esse que complementa a sua experiência de ida ao cinema. Consequentemente, este estudo é capaz de retirar algumas conclusões relevantes para a indústria. Os participantes demonstraram reações muito positivas quando confrontados com cenários experienciais que, por sua vez, contribuem para a experiência da marca no geral. Em termos comportamentais, os resultados revelam que os participantes sentem que estes cenários iriam melhorar a sua relação com a marca e encorajá-los a serem parte de uma audiência mais assídua nos cinemas

Is T-mobile U.S. a good target for Comcast

Throughout 2015 there was a rumor in the market that the U.S.-based cable company, Comcast, could be expanding its segments to wireless. Despite offering cable TV, broadband and voice or even by operating theme parks, the company may be after T-Mobile U.S., a Deutsche Telekom subsidiary. Despite its failed attempt to buy Time-Warner Cable, it is expected that such a deal would occur for Comcast in a near future. Therefore, following the company strategic objectives, this thesis stresses the effects of acquiring T-Mobile U.S. in both, financial and strategic terms. With total synergies expected to achieve $5,130M and a total premium of$4,429M, such a deal would bring Comcast a net benefit of $5,632M. With a final price offer of$41.61 per share, the deal is recommended and should occur as soon as possible for the sake of the companies in the process.Ao longo de 2015 houve rumores no mercado de que a Comcast - empresa de cabo que opera nos Estados Unidos, poderia expandir a sua atividade em direção à indústria de telecomunicações móveis. Mesmo tendo segmentos como televisão por cabo, internet e voz, ou até mesmo parques de diversão temáticos, é possível que a empresa esteja inclinada a comprar a T-Mobile U.S., subsidiária americana da Deutsche Telekom. Depois de falhada a tentativa de compra da Time Warner Cable, é possível que a Comcast continue a procurar novos negócios dentro do mesmo segmento num futuro próximo. Assim, e de acordo com os objetivos estratégicos da empresa, esta tese pretende identificar quais as consequências de tal aquisição, em termos financeiros e estratégicos. Com sinergias totais estimadas em $5,130M e um prémio de$4,429M, a Comcast teria um benefício líquido de $5,632M. Com um preço final de$41.61 por ação, e tendo em conta os objetivos das duas empresas, o negócio é recomendando e deve até ocorrer nos próximos tempos para beneficio das partes envolvidas

Néstor García Canclini and cultural policy in Latin America

This thesis examines Néstor García Canclini´s relationships with various non-academic institutions in Latin America (focusing on Mexico) during the 1990s and the 2000s. It emphasises the shortage of communication between scholars and non-academic policymaking institutions through its study of García Canclini´s cultural policy activism. By investigating García Canclini’s activities with various Latin American non-academic institutions (and particularly those from Mexico), this thesis argues that he not only conceptualises and proposes cultural policy; he also conducts cultural policy. Through his discussion of cultural issues with bureaucrats, legislators, policy-makers, politicians, private managers and newspaper editors, this thesis evaluates his most important engagements to present how cultural policy can move from being an institutionallyoriented instrument to an intellectually-oriented operation. This thesis raises key theoretical debates such as the role of intellectuals in Latin America, cultural policy institutional development, cultural spaces, national development, urban studies, the cultural industries, globalisation and identities, and the multiplicity of cultural policy-makers. In addition, analyses of García Canclini´s academic and conceptual developments as well as a study of the extensive networks he formed beyond academia show how he utilised his extra-academic activities in Latin America to encourage cultural issues through his cultural policy activism. This thesis concludes that García Canclini broke university boundaries through his cultural policy operation without ever speaking from a position other than that of an academic

O trabalho de prevenção na formação profissional

A Formação Profissional apresenta-se-nos como um local onde interagem duas problemáticas, às quais somos sensíveis e que no nosso entender se correlacionam, a saber: o Desemprego e o Risco Rodoviário. Neste trabalho, apresentamos um modelo de intervenção adaptado ao contexto dos Centros de Formação Profissional e os aspectos mais relevantes que dele emanam, no que concerne às problemáticas em jogo. Apesar de ser ainda um estudo exploratório, a reflexão que temos vindo a fazer, atesta da pertinência destas acções no âmbito da prevenção rodoviária, assim como, da sua importância em termos de Saúde Pública.Professional Training can be seen as a place where two problematics interact, to which we are sensitive and that, according to our opinion, are correlated: Unemployment and Roadway Risk. We present a model of intervention adapted to the context of the Professional Training Centers and the most relevant aspects which proceed from it, concerning the given problematics. Although it is still an exploratory study, the meditation we have been making on this issue proves the pertinence of these actions aiming at Road Safety Prevention, as well as its importance in terms of Public Health.info:eu-repo/semantics/publishedVersio

O trabalho de prevenção na formação profissional

A Formação Profissional apresenta-se-nos como um local onde interagem duas problemáticas, às quais somos sensíveis e que no nosso entender se correlacionam, a saber: o Desemprego e o Risco Rodoviário. Neste trabalho, apresentamos um modelo de intervenção adaptado ao contexto dos Centros de Formação Profissional e os aspectos mais relevantes que dele emanam, no que concerne às problemáticas em jogo. Apesar de ser ainda um estudo exploratório, a reflexão que temos vindo a fazer, atesta da pertinência destas acções no âmbito da prevenção rodoviária, assim como, da sua importância em termos de Saúde Pública

Escaping mediocrity: how two-layer networks learn hard single-index models with SGD

This study explores the sample complexity for two-layer neural networks to learn a single-index target function under Stochastic Gradient Descent (SGD), focusing on the challenging regime where many flat directions are present at initialization. It is well-established that in this scenario $n=O(d\log{d})$ samples are typically needed. However, we provide precise results concerning the pre-factors in high-dimensional contexts and for varying widths. Notably, our findings suggest that overparameterization can only enhance convergence by a constant factor within this problem class. These insights are grounded in the reduction of SGD dynamics to a stochastic process in lower dimensions, where escaping mediocrity equates to calculating an exit time. Yet, we demonstrate that a deterministic approximation of this process adequately represents the escape time, implying that the role of stochasticity may be minimal in this scenario