Boundary conditions and renormalized stress-energy tensor on a Poincar\'e patch of AdS2\textrm{AdS}_2

Quantum field theory on anti-de Sitter spacetime requires the introduction of boundary conditions at its conformal boundary, due essentially to the absence of global hyperbolicity. Here we calculate the renormalized stress-energy tensor $T_{\mu\nu}$ for a scalar field $\phi$ on the Poincar\'e patch of $\text{AdS}_2$ and study how it depends on those boundary conditions. We show that, except for the Dirichlet and Neumann cases, the boundary conditions break the maximal $\textrm{AdS}$ invariance. As a result, $\langle\phi^2\rangle$ acquires a space dependence and $\langle T_{\mu\nu}\rangle$ is no longer proportional to the metric. When the physical quantities are expanded in a parameter $\beta$ which characterizes the boundary conditions (with $\beta=0$ corresponding to Dirichlet and $\beta=\infty$ corresponding to Neumann), the singularity of the Green's function is entirely subtracted at zeroth order in $\beta$. As a result, the contribution of nontrivial boundary conditions to the stress-energy tensor is free of singular terms.Comment: 7 pages. Minor Correction. Matches published versio

From rapid prototyping to building in real scale: methodologies for upscaling additive manufacturing in architecture

The manufacture of architectural components mediated by computer-controlled Additive Manufacturing (AM) technologies has highlighted several positive aspects of their application, namely by enabling customised design solutions and high-performance complex geometries. Taking into account the experience of the Advanced Ceramics R&D Lab, in the production of small- / medium- scale prototypes, this paper explores the main variables and constraints of the production of real-scale architectural components. This information points to a set of procedures that should be avoided and others that should be privileged, allowing to anticipate how AM can contribute for the achievement of high performance components on a large scale.This work has the financial support of the Project Lab2PT – Landscapes, Heritage and Territory laboratory – AUR/04509 and FCT through national founds and when applicable of the FEDER cofinancing, in the aim of the new partnership agreement PT2020 and COMPETE2020 – POCI 01 0145FEDER 007528

Contact in Foster Care: Bridge or Collision between Two Worlds?

This study aims not only to analyze the contact in foster care in Portugal compared to results collected from other studies but also to define the implications of its practice so as to propose improvements to the child protection system. It involves 289 foster children from the District of Porto whose results were obtained from official records. Subsequently, this study discusses the insights and practical consequences, the importance of maintaining up-to-date information on the changes of the biological family, the need to improve specific skills in social workers, and how to overlook the negative results of visits regarding the advantages and risks of maintaining contact

Percepciones de los niños sobre contacto y bienestar subjetivo en cuidado residencial y en acogida familiar

[EN] Contact between children in foster and residential care and their birth fami-lies have an impact on children’s development and on placement stability. Contact is also important for their social relationships and sense of belonging and well-being. The aim of this study was, from children’s point of view, to describe, analyse and compare contact in residential care and foster care in terms of its frequency, visit location, feelings during and after the visits, visit difficulties, happiness with their placement, their self-confidence, future perception about their lives, and perception of their subjective well-being. We used a sample of 145 children in residential care and all the children in foster care (39), aged between 11 and 15, from the same four Portuguese districts. Results indicated that children in residential care had more contact and visits with their parents than children in foster care, being phone calls the most used way to contact the children. The majority of the children presented joy or sat-isfaction during parents’ visits and more diffuse feelings after the visit. Also, most of children would like to have more visits and just a minority present some difficulties in their fulfilment. Nevertheless, children in foster care had more self-confidence, optimism in relation to their future, happiness in relation to their placement and higher subjective well-being than children in residential care. In summary, it seemed that the type of placement for children at risk is more important to their future than the existence of contact with their parents. [ES] El contacto entre los niños en acogida familiar y residencial y sus familias bioló-gicas tiene un impacto en el desarrollo de los niños y en la estabilidad de la colocación. El contacto también es importante para sus relaciones sociales y su sentido de pertenencia y bienestar. El objetivo de este estudio fue, desde el punto de vista de los niños, describir, ana-lizar y comparar el contacto en el cuidado residencial y en la acogida familiar en términos de su frecuencia, ubicación de la visita, sentimientos durante y después de las visitas, dificultades de la visita, felicidad con su colocación, su autoconfianza, percepción futura sobre sus vidas y percepción de su bienestar subjetivo. Utilizamos una muestra de 145 niños en cuidado resi-dencial y todos los niños en acogida familiar (39), de edades comprendidas entre 11 y 15 años, de los mismos cuatro distritos portugueses. Los resultados indicaron que los niños en cuidado residencial tuvieron más contacto y visitas con sus padres que los niños en acogida familiar, siendo las llamadas telefónicas la forma más utilizada para contactar a los niños. La mayoría de los niños presentaron alegría o satisfacción durante las visitas de los padres y sentimientos más difusos después de la visita. Además, a la mayoría de los niños les gustaría tener más visitas y solo una minoría presenta algunas dificultades para su cumplimiento. Sin embargo, los niños en acogida familiar tenían más confianza en sí mismos, optimismo en relación con su futuro, felicidad en relación con su colocación y un mayor bienestar subjetivo que los niños en cuidado residencial. En resumen, parecía que el tipo de colocación para niños en riesgo es más importante para su futuro que la existencia de contacto con sus padres. [PT] O contacto entre crianças em acolhimento familiar e residencial e as suas famí-lias de nascimento tem um impacto no desenvolvimento das crianças e na estabilidade da sua colocação. O contacto também é importante para as suas relações sociais e sentido de pertença e bem-estar. O objetivo deste estudo foi, do ponto de vista das crianças, descrever, analisar e comparar o contacto no acolhimento familiar e no acolhimento residencial em ter-mos de frequência, localização da visita, sentimentos durante e após as visitas, dificuldades na visita, felicidade com sua colocação, a sua autoconfiança, a perceção futura sobre as suas vidas e a perceção do seu bem-estar subjetivo. Utilizamos uma amostra de 145 crianças em cuidados residenciais e todas as crianças em acolhimento familiar (39), com idades entre os 11 e os 15 anos, dos mesmos quatro distritos portugueses. Os resultados indicaram que as crianças em cuidados residenciais tiveram mais contacto e visitas com os pais do que crianças em acolhimento familiar, sendo as chamadas telefónicas a forma mais utilizada de contacto com as crianças. A maioria das crianças apresentou alegria ou satisfação durante as visitas dos pais e sentimentos mais difusos após a visita. Além disso, a maioria das crianças gostaria de ter mais visitas e apenas uma minoria apresenta algumas dificuldades com a sua realização. No entanto, as crianças em acolhimento familiar tinham mais autoconfiança, otimismo em relação ao seu futuro, felicidade em relação à sua colocação e maior bem-estar subjetivo do que as crianças em cuidados residenciais. Em resumo, parecia que o tipo de colocação para as crianças em risco seria mais importante para o seu futuro do que a existência de contacto com os pais

Quantum Singularities Around a Global Monopole

The behavior of a massive scalar particle on the spacetime surrounding a monopole is studied from a quantum mechanical point of view. All the boundary conditions necessary to turn into self-adjoint the spatial portion of the wave operator are found and their importance to the quantum interpretation of singularities is emphasized.Comment: 5 pages, revte

A constitutive three-dimensional interface model for masonry walls subjected to high strain rates

Investigation of the dynamic properties of construction materials is critical for structural engineering. The strain rate effect influences the properties of most constructions materials and this effect on materials such as concrete or steel has been intensively investigated. However, such studies on masonry materials are scarce. Understanding the strain rate effect on masonry materials is important for proper modelling and design of masonry structures under high velocity impacts or blast loads. The work, described in this paper, aims to study the behaviour of masonry at different strain rates. First, a drop weight impact machine is used at different heights and weights introducing different levels of strain rate. Then, a dynamic constitutive material interface model that includes an non-associated flow rule and high strain rate effects is proposed. The model capability is validated with numerical simulations of unreinforced block work masonry walls subjected to impact.(undefined

Attitudes and decision-making in the child protection system: a comparison of students and professionals

In the contexts of family neglect or maltreatment, the State intervenes by safeguarding the development and well-being of the child or young person in danger. In more severe situations, the intervention may lead to the child’s removal from the family. The Portuguese Law on the Protection of Children and Young People in Danger (Law 142/2015 of September 8th) favours the placement of the child in a family environment, especially for children up to the age of six. Despite this, in Portugal, in 2015, 8 600 children were in out-of-home care, only 3.5% of which were placed in foster care, while the remaining children were in residential care. Therefore, one of the fundamental rights of the child – living in a family environment – is compromised in practice. This study aims to understand the decision-making process of 200 higher education students in domains related to child protection, and those of 200 professionals who are responsible for providing case assessments and recommendations for intervention in the Portuguese child protection system. Using the Child Welfare Attitudes Questionnaire (Davidson-Arad & Benbenishty, 2008, 2010), the study aimed to identify the participants’ attitudes regarding removal of at-risk children from home, reunification and optimal duration of alternative care, children’s and parents’ participation in the decision-making process, and assessment of foster care and residential care, with the purpose of promoting children’s development and well-being. We concluded that both sets of participants (professionals and students) can be divided in two groups, one which is pro-removal and the other, which is less so. In comparison with students, professionals less often favour the removal of the child and more often defend reunification. There are no significant differences among participants regarding their opinion about the role of foster and residential care, and the participation of the child in the decision-making process. However, professionals tend to support parents’ participation in the decision-making process more than students do. Finally, we present some implications of our findings for the practice of child protection