Classical solutions and their double copy in split signature

The three-point amplitude is the key building block in the on-shell approach to scattering amplitudes. We show that the classical objects computed by massive three-point amplitudes in gauge theory and gravity are Newman-Penrose scalars in a split-signature spacetime, where three-point amplitudes can be defined for real kinematics. In fact, the quantum state set up by the particle is a coherent state fully determined by the three-point amplitude due to an eikonal-type exponentiation. Having identified this simplest classical solution from the perspective of scattering amplitudes, we explore the double copy of the Newman-Penrose scalars induced by the traditional double copy of amplitudes, and find that it coincides with the Weyl version of the classical double copy. We also exploit the Kerr-Schild version of the classical double copy to determine the exact spacetime metric in the gravitational case. Finally, we discuss the direct implication of these results for Lorentzian signature via analytic continuation.Comment: 45 pages, 5 figure

The electric vehicle in smart homes: a review and future perspectives

The electric mobility dissemination is forcing the adoption of new technologies and operation paradigms, not only focusing on smart grids, but also on smart homes. In fact, the emerging technologies for smart homes are also altering the conventional grids toward smart grids. By combining the key pillars of electric mobility and smart homes, this paper characterizes the paradigms of the electric vehicle (EV) in smart homes, presenting a review about the state of the art and establishing a relation with future perspectives. Since the smart home must be prepared to deal with the necessities of the EV, the analysis of both on board and off board battery charging systems are considered in the paper. Moreover, the in-clusion of renewable energy sources, energy storage systems, and dc electrical appliances in smart homes towards sustainability is also considered in this paper, but framed in the perspective of an EV off board battery charging system. As a pertinent contribution, this paper offers future perspectives for the EV in smart homes, including the possibility of ac, dc, and hybrid smart homes. Covering all of these aspects, exemplificative and key results are presented based on numerical simulations and experimental results obtained with a proof of concept prototype.FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2019. This work has been supported by the FCT Project newERA4GRIDs PTDC/EEI-EEE/30283/2017, and by the FCT Project DAIPESEV PTDC/EEI-EEE/30382/2017. Tiago Sousa is supported by the doctoral scholarship SFRH/BD/134353/2017 granted by FC

Weyl Double Copy for Gravitational Waves

We establish the status of the Weyl double copy relation for radiative solutions of the vacuum Einstein equations. We show that all type N vacuum solutions, which describe the radiation region of isolated gravitational systems with appropriate falloff for the matter fields, admit a degenerate Maxwell field that squares to give the Weyl tensor. The converse statement also holds, i.e., if there exists a degenerate Maxwell field on a curved background, then the background is type N . This relation defines a scalar that satisfies the wave equation on the background. We show that for nontwisting radiative solutions, the Maxwell field and the scalar also satisfy the Maxwell equation and the wave equation on Minkowski spacetime. Hence, nontwisting solutions have a straightforward double copy interpretation

The role of off-board EV battery chargers in smart homes and smart grids: operation with renewables and energy storage systems

Concerns about climate changes and environmental air pollution are leading to the adoption of new technologies for transportation, mainly based on vehicle electrification and the interaction with smart grids, and also with the introduction of renewable energy sources (RES) accompanied by energy storage systems (ESS). For these three fundamental pillars, new power electronics technologies are emerging to transform the electrical power grid, targeting a flexible and collaborative operation. As a distinctive factor, the vehicle electrification has stimulated the presence of new technologies in terms of power management, both for smart homes and smart grids. As the title indicates, this book chapter focuses on the role of off-board EV battery chargers in terms of operation modes and contextualization for smart homes and smart grids in terms of opportunities. Based on a review of on-board and off-board EV battery charging systems (EV-BCS), this chapter focus on the off-board EV-BCS framed with RES and ESS as a dominant system in future smart homes. Contextualizing these aspects, three distinct cases are considered: (1) An ac smart home using separate power converters, according to the considered technologies; (2) A hybrid ac and dc smart home with an off-board EV-BCS interfacing RES and ESS, and with the electrical appliances plugged-in to the ac power grid; (3) A dc smart home using a unified 2 off-board EV-BCS with a single interface for the electrical power grid, and with multiple dc interfaces (RES, ESS, and electrical appliances). The results for each case are obtained in terms of efficiency and power quality, demonstrating that the off-board EV-BCS, as a unified structure for smart homes, presents better results. Besides, the off-board EV-BCS can also be used as an important asset for the smart grid, even when the EV is not plugged-in at the smart home.(undefined

Fractal analysis of right ventricular trabeculae in pulmonary hypertension

Purpose: To measure right ventricular (RV) trabecular complexity by its fractal dimension (FD) in healthy subjects and patients with pulmonary hypertension (PH) and assess its relationship to hemodynamic and functional parameters, and future cardiovascular events. Materials and methods: This retrospective study used data acquired from May 2004 to October 2013 for 256 patients with newly-diagnosed PH that underwent cardiac magnetic resonance (CMR) imaging, right heart catheterization and six-minute walk distance testing with a median follow-up of 4.0 years. 256 healthy controls underwent CMR only. Biventricular FD, volumes and function were assessed on short-axis cine images. Reproducibility was assessed by intraclass correlation coefficient, correlation between variables was assessed by Pearson’s correlation test, and mortality prediction compared by univariable and multivariable Cox regression analysis. Results: RV-FD reproducibility had an intraclass correlation coefficient of 0.97 (95% confidence interval [CI]: 0.96, 0.98). RV-FD was higher in PH patients than healthy subjects (median 1.310, inter-quartile range [IQR] 1.281-1.341 vs 1.264, 1.242-1.295, P <.001) with the greatest difference near the apex. RV-FD was associated with pulmonary vascular resistance (r=0.30, P <.001). In univariable Cox regression analysis, RV-FD was a significant predictor of death (hazards ratio [HR]: 1.256, CI: 1.011, 1.560, P =.04), but in a multivariable analysis did not predict survival independently of conventional parameters of RV remodeling (HR: 1.179, CI: 0.871, 1.596, P =0.29). Conclusion: Fractal analysis of RV trabecular complexity is a highly reproducible measure of remodeling in PH associated with afterload, although the gain in survival prediction over traditional markers is not significant

A cryo-EM grid preparation device for time-resolved structural studies

Structural biology generally provides static snapshots of protein conformations that can provide information on the functional mechanisms of biological systems. Time-resolved structural biology provides a means to visualize, at near-atomic resolution, the dynamic conformational changes that macromolecules undergo as they function. X-ray free-electron-laser technology has provided a powerful tool to study enzyme mechanisms at atomic resolution, typically in the femtosecond to picosecond timeframe. Complementary to this, recent advances in the resolution obtainable by electron microscopy and the broad range of samples that can be studied make it ideally suited to time-resolved approaches in the microsecond to millisecond timeframe to study large loop and domain motions in biomolecules. Here we describe a cryo-EM grid preparation device that permits rapid mixing, voltage-assisted spraying and vitrification of samples. It is shown that the device produces grids of sufficient ice quality to enable data collection from single grids that results in a sub-4 Å reconstruction. Rapid mixing can be achieved by blot-and-spray or mix-and-spray approaches with a delay of ∼10 ms, providing greater temporal resolution than previously reported mix-and-spray approaches

Condições de vida e vocabulário receptivo em crianças de dois a cinco anos

OBJECTIVE: To assess the receptive vocabulary of children aged between two years and six months and five years and eleven months who were attending childcare centers and kindergarten schools. METHODS: An analytical cross-sectional study was carried out in the municipality of Embu, Southeastern Brazil. The Peabody Picture Vocabulary Test and analysis of factors associated with children's performance were applied. The sample consisted of 201 children of both genders, aged between two and six years. Statistical analysis was performed using multivariate analysis and logistic regression model. The dependent variable analyzed was test performance and the independent variables were child's age, mother's level of education and family socio-demographic characteristics. RESULTS: It was observed that 44.3% of the children had performances in the test that were below what would be expected for their age. The factors associated with the best performances in the test were child's age (OR=2.4; 95% CI: 1.6-3.5) and mother's education level (OR= 3.2; 95% CI: 1.3-7.4). CONCLUSIONS: Mother's education level is important for child's language development. Settings such as childcare and kindergarten schools are protective factors for child development in families of low income and education.OBJETIVO: Avaliar o vocabulário receptivo de crianças de dois anos e seis meses a cinco anos e 11 meses que freqüentam creches e pré-escolas. MÉTODOS: Estudo transversal e analítico realizado no município de Embu, Estado de São Paulo. Utilizou-se o Teste de Vocabulário por Imagem Peabody e análise de fatores associados ao desempenho. A amostra foi constituída de 201 crianças de ambos os sexos, com idade entre dois e seis anos. Foram realizados análise multivariada e modelo de regressão logística. A variável dependente analisada foi o desempenho no teste e as variáveis independentes foram a idade da criança, tempo de escolaridade e série, e características sociodemográficas de suas famílias. RESULTADOS: Observou-se que 44,3% das crianças apresentaram desempenho inferior ao esperado para a idade no teste e os fatores associados ao melhor desempenho foram a idade da criança (OR=2,4; IC 95%: 1,6-3,5) e a escolaridade materna (OR=3,2; IC 95%: 1,3-7,4). CONCLUSÕES: A escolaridade maternal é importante no desenvolvimento de linguagem da criança. As instituições como creches e pré- escolas são fatores de proteção do desenvolvimento infantil em famílias de baixa renda e com baixa escolaridade.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de FonoaudiologiaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de PediatriaUNIFESP, EPM, Depto. de FonoaudiologiaUNIFESP, EPM, Depto. de PediatriaSciEL