Noether-Wald energy in Critical Gravity

Criticality represents a specific point in the parameter space of a higher-derivative gravity theory, where the linearized field equations become degenerate. In 4D Critical Gravity, the Lagrangian contains a Weyl-squared term, which does not modify the asymptotic form of the curvature. The Weyl$^{2}$ coupling is chosen such that it eliminates the massive scalar mode and it renders the massive spin-2 mode massless. In doing so, the theory turns consistent around the critical point. Here, we employ the Noether-Wald method to derive the conserved quantities for the action of Critical Gravity. It is manifest from this energy definition that, at the critical point, the mass is identically zero for Einstein spacetimes, what is a defining property of the theory. As the entropy is obtained from the Noether-Wald charges at the horizon, it is evident that it also vanishes for any Einstein black hole.Comment: 7 pages, no figures, Final version for PL

Monitoring water-soil dynamics and tree survival using soil sensors under a big data approach

ArticleThe high importance of green urban planning to ensure access to green areas requires modern and multi-source decision-support tools. The integration of remote sensing data and sensor developments can contribute to the improvement of decision-making in urban forestry. This study proposes a novel big data-based methodology that combines real-time information from soil sensors and climate data to monitor the establishment of a new urban forest in semi-arid conditions. Water-soil dynamics and their implication in tree survival were analyzed considering the application of di erent treatment restoration techniques oriented to facilitate the recovery of tree and shrub vegetation in the degraded area. The synchronized data-capturing scheme made it possible to evaluate hourly, daily, and seasonal changes in soil-water dynamics. The spatial variation of soil-water dynamics was captured by the sensors and it highly contributed to the explanation of the observed ground measurements on tree survival. The methodology showed how the e ciency of treatments varied depending on species selection and across the experimental design. The use of retainers for improving soil moisture content and adjusting tree-watering needs was, on average, the most successful restoration technique. The results and the applied calibration of the sensor technology highlighted the random behavior of water-soil dynamics despite the small-scale scope of the experiment. The results showed the potential of this methodology to assess watering needs and adjust watering resources to the vegetation status using real-time atmospheric and soil datainfo:eu-repo/semantics/publishedVersio

Social security system in Portugal : feasibility and impact of its approximation to the chilean model

Mestrado em Ciências ActuariaisVárias projeções da evolução do sistema de Segurança Social em Portugal indicam que está faltando a sustentabilidade em sua forma atual, daí a necessidade de fazer correções a esta tendência. Em contraste algumas evidências sugerem que o Sistema de Segurança Social em Chile está desfrutando de sustentabilidade. A fim de contribuir para o debate nacional sobre a forma como estes pazes deve ter lugar, uma visão sobre as características de ambos: o sistema de fundos de pensão Português e do modelo chileno será discutido, destacando seus pontos fortes e fracos que nos permitam fazer uma análise custo / benefício para a transição do atual sistema de Português para um sistema mais parecido com o chileno.Several Projections of the Social Security System evolution in Portugal indicate it's lacking of sustainability in its present form, hence the need to make corrections to this trend. In contrast some evidence suggests that the Social Security System in Chile is enjoying sustainability. In order to contribute to the national discussion on the way these amends should take place, an insight into the characteristics of both: the Portuguese pension fund system and the Chilean model will be discussed, highlighting their strengths and weaknesses that will allow us to do a cost/benefit analysis for the transition of the current Portuguese system to a system more similar to the Chilean

Peripheral Meson Model of Deep Inelastic Rapidity Gap Events

We show that a peripheral meson model can explain the large deep inelastic electron-proton scattering rapidity gap events observed at HERA.Comment: 12 pages, 2 figure

Topological Data Analysis for Portfolio Management of Cryptocurrencies

Portfolio management is essential for any investment decision. Yet, traditional methods in the literature are ill-suited for the characteristics and dynamics of cryptocurrencies. This work presents a method to build an investment portfolio consisting of more than 1500 cryptocurrencies covering 6 years of market data. It is centred around Topological Data Analysis (TDA), a recent approach to analyze data sets from the perspective of their topological structure. This publication proposes a system combining persistence landscapes to identify suitable investment opportunities in cryptocurrencies. Using a novel and comprehensive data set of cryptocurrency prices, this research shows that the proposed system enables analysts to outperform a classic method from the literature without requiring any feature engineering or domain knowledge in TDA. This work thus introduces TDA-based portfolio management of cryptocurrencies as a viable tool for the practitioner