Gravitational wave recoils in non-axisymmetric Robinson-Trautman spacetimes

We examine the gravitational wave recoil waves and the associated net kick velocities in non-axisymmetric Robinson-Trautman spacetimes. We use characteristic initial data for the dynamics corresponding to non-head-on collisions of black holes. We make a parameter study of the kick distributions, corresponding to an extended range of the incidence angle $\rho_0$ in the initial data. For the range of $\rho_0$ examined ($3^{\circ} \leq \rho_0 \leq 110^{\circ}$) the kick distributions as a function of the symmetric mass parameter $\eta$ satisfy a law obtained from an empirical modification of the Fitchett law, with a parameter $C$ that accounts for the non-zero net gravitational momentum wave fluxes for the equal mass case. The law fits accurately the kick distributions for the range of $\rho_0$ examined, with a rms normalized error of the order of $5 \%$. For the equal mass case the nonzero net gravitational wave momentum flux increases as $\rho_0$ increases, up to $\rho_0 \simeq 55^{\circ}$ beyond which it decreases. The maximum net kick velocity is about $190 {\rm km/s}$ for for the boost parameter considered. For $\rho_0 \geq 50^{\circ}$ the distribution is a monotonous function of $\eta$. The angular patterns of the gravitational waves emitted are examined. Our analysis includes the two polarization modes present in wave zone curvature.Comment: 10 pages, 5 figures. arXiv admin note: substantial text overlap with arXiv:1403.4581, arXiv:1202.1271, arXiv:1111.122

Escola e tecnologias digitais: conexões contemporâneas

A intenção deste estudo foi analisar uso a tecnologia digital no ensino de primária, secundária e bacheralado em algumas escolas de Sevilha/Espanha, motivados pela centralidade dessas no cotidiano da sociedade. A problematizaçao foi analisar as potencialidades e operacionalidades das tecnologias digitais como dispositivos didáticos implicados no ensino. As analises apontam que conexões entre praticas escolares e tecnologias digitais ampliam as capacidades cognitivas e conectam novos recursos com o mundo dos jovens estudantes.Pesquisa realizada com apoio CAPES, através do Processo BEX 7106-14-9

Towards BitCO2, an individual consumption-based carbon emission reduction mechanism

Human activities, such as burning fossil fuels for electricity generation, heating, and transport, are the primary drivers of a large amount of greenhouse gases emission. The individual consumers, able to influence the supply chains behind the commodities their chose to fulfil their needs is the driver behind production and, consequently, its impacts. Thus, the active and willing participation of citizens in combatting climate change may be pivotal to address this issue. The present work is aimed at presenting and modelling a novel market-based carbon emission reduction mechanism, called BitCO2, designed to incentivize individual consumption choices toward lower carbon footprints. This mechanism is tested for the Italian private transportation sector thanks to an ad hoc developed System Dynamics model. The Battery Electric Vehicle (BEV) adoption, if compared with the Internal Combustion Engine Vehicle (ICEV) one, cause less CO2 emissions per km travelled. After a certain number of travelled km, a BitCO2 token is assigned to BEV owners for each ton of avoided CO2. This token can be exchanged in a dedicated market and used to get a discount on insurance services. Assuming a Social Cost of Carbon of 9.22 [2.13-22.3] euro/tonCO2eq, model results show that the BitCO2 mechanism would allow for a cumulated CO2 emission reduction of 973 [68.9-5'230] ktonCO2eq over 20 years of operation with a peak of 39.3 [5.34-189] thousand additional BEV registration per year

Tsunami hazard for the city of Catania, eastern Sicily, Italy, assessed by means of Worst-case Credible Tsunami Scenario Analysis (WCTSA)

Eastern Sicily is one of the coastal areas most exposed to earthquakes and tsunamis in Italy. The city of Catania that developed between the eastern base of Etna volcano and the Ionian Sea is, together with the neighbour coastal belt, under the strong menace of tsunamis. This paper addresses the estimation of the tsunami hazard for the city of Catania by using the technique of the Worst-case Credible Tsunami Scenario Analysis (WCTSA) and is focused on a target area including the Catania harbour and the beach called La Plaia where many human activities develop and many important structures are present. The aim of the work is to provide a detailed tsunami hazard analysis, firstly by building scenarios that are proposed on the basis of tectonic considerations and of the largest historical events that hit the city in the past, and then by combining all the information deriving from single scenarios into a unique aggregated scenario that can be viewed as the <i>worst virtual scenario</i>. Scenarios have been calculated by means of numerical simulations on computational grids of different resolutions, passing from 3 km on a regional scale to 40 m in the target area. La Plaia beach results to be the area most exposed to tsunami inundation, with inland penetration up to hundreds of meters. The harbour turns out to be more exposed to tsunami waves with low frequencies: in particular, it is found that the major contribution to the hazard in the harbour is due to a tsunami from a remote source, which propagates with much longer periods than tsunamis from local sources. This work has been performed in the framework of the EU-funded project SCHEMA

Economic benefit and social impact derived by a food loss prevention strategy in the vegetable sector: A spatial and temporal analysis at the regional level

Introduction: Reduction of food loss in the horticultural sector is critical to simultaneously support the transition toward a diet with higher consumption of vegetables and the achievement of policy goals aimed at halving the quantity of wastage by 2030. However, the lack of precise information and the presence of múltiple interconnected factors makes it difficult to assess the potential socioeconòmic benefits and therefore the decision-making process of food loss reduction strategies. Methods: A case study approach has been used to assess the econòmic loss and nutrional impact of food loss in the horticulture primary production. The selection of the main vegetable products was based on an historical series while econòmic and nutritional impact were estimated starting from national and European indicator. Results: The food loss correspond to 26% of the total production and 14% of the total agricultural production econòmic value. The social analysis confirm the possibility of redistributing food loss among the population even in the most critical months and areas. Discussion: The combination of social and econòmic indicator resulted essential to provide key information at the decision-making level to pave the way for the elaboration of short- and long-term food loss reduction strategies. Indeed, no single-bullet strategy can be applied to overcome the problem of food loss as many actor with different needs are involved

A life cycle assessment framework for large-scale changes in material circularity

Increasing material circularity is high on the agenda of the European Union in order to decouple environmental impacts and economic growth. While life cycle assessment (LCA) is useful for quantifying the associated environmental impacts, consistent LCA modeling of the large-scale changes arising from policy targets addressing material circularity (i.e., recycled content and recycling rate) is challenging. In response to this, we propose an assessment framework addressing key steps in LCA, namely, goal definition, functional unit, baseline versus alternative scenario definition, and modeling of system responses. Regulatory and economic aspects (e.g., trends in consumption patterns, market responses, market saturation, and legislative side-policies affecting waste management) are emphasized as critical for the identification of potential system responses and for supporting regulatory interventions required to reach the intended environmental benefits. The framework is recommended for LCA studies focusing on system-wide consequences where allocation between product life cycles is not relevant; however, the framework can be adapted to include allocation. The application of the framework was illustrated by an example of implementing a policy target for 2025 of 70% recycled content in PET trays in EU27+1. It was demonstrated that neglecting large-scale market responses and saturation lead to an overestimation of the environmental benefits from the policy target and that supplementary initiatives are required to achieve the full benefits at system level