Senescence in vitro and ionising radiations—the human diploid fibroblast model

The influence of ionising radiations on ageing is still controversial. Since Hayflick established the concept that diploid cells have finite lifespan in vitro, human diploid fibroblast (HDF) cultures have been recognised as a potent experimental model for cytogerontological investigations. In this study HDF cultures in phase II were exposed to acute irradiation with either X-rays on fast neutrons. The replicative potentials and labelling indices with [3H]thymidine were measured post irradiation until the cultures ceased growth in phase III. Cell mortality was measured by cloning. The apparent loss in replicative potential of irradiated mass cultures was wholly attributable to the loss of viable clonogenic cells. The current concept of precocious clonal senescence in vitro as a late effect of irradiation in clonogenic survivors is not supported by the present experiments. Instead, our results suggest that exposure to a single dose of ionising radiations either causes total replicative incapacitation (killing) of HDF cells and their progeny early after irradiation or leaves their replicative potentials unperturbed

Modelo de especificação e controlo de execuções paralelas e distribuídas

O desenvolvimento actual de aplicações paralelas com processamento intensivo (HPC - High Performance Computing) para alojamento em computadores organizados em Cluster baseia-se muito no modelo de passagem de mensagens, do qual é de realçar os esforços de definição de standards, por exemplo, MPI - Message - Passing Interface. Por outro lado, com a generalização do paradigma de programação orientado aos objectos para ambientes distribuídos (Java RMI, .NET Remoting), existe a possibilidade de considerar que a execução de uma aplicação, de processamento paralelo e intensivo, pode ser decomposta em vários fluxos de execução paralela, em que cada fluxo é constituído por uma ou mais tarefas executadas no contexto de objectos distribuídos. Normalmente, em ambientes baseados em objectos distribuídos, a especificação, controlo e sincronização dos vários fluxos de execução paralela, é realizada de forma explicita e codificada num programa principal (hard-coded), dificultando possíveis e necessárias modificações posteriores. No entanto, existem, neste contexto, trabalhos que propõem uma abordagem de decomposição, seguindo o paradigma de workflow com interacções entre as tarefas por, entre outras, data-flow, control-flow, finite - state - machine. Este trabalho consistiu em propor e explorar um modelo de execução, sincronização e controlo de múltiplas tarefas, que permita de forma flexível desenhar aplicações de processamento intensivo, tirando partido da execução paralela de tarefas em diferentes máquinas. O modelo proposto e consequente implementação, num protótipo experimental, permite: especificar aplicações usando fluxos de execução; submeter fluxos para execução e controlar e monitorizar a execução desses fluxos. As tarefas envolvidas nos fluxos de execução podem executar-se num conjunto de recursos distribuídos. As principais características a realçar no modelo proposto, são a expansibilidade e o desacoplamento entre as diferentes componentes envolvidas na execução dos fluxos de execução. São ainda descritos casos de teste que permitiram validar o modelo e o protótipo implementado. Tendo consciência da necessidade de continuar no futuro esta linha de investigação, este trabalho é um contributo para demonstrar que o paradigma de workflow é adequado para expressar e executar, de forma paralela e distribuída, aplicações complexas de processamento intensivo

Pedidos de informação em projectos de construção : caracterização e aplicação a uma caso de estudo

Tese de mestrado integrado. Engenharia Civil. Faculdade de Engenharia. Universidade do Porto. 201

Bundling incentives in markets with product complementarities: The case of triple-play

We analyze firms' incentives to bundle and tie in the telecommunications industry. As a first step, we develop a discrete-choice demand model where firms sell products that may combine several services in bundles, and consumers choose assortments of different types of products available from various vendors. Our approach extends standard discrete-choice demand models of differentiated product to allow for both flexible substitution patterns and to map demand for each choice alternative onto the demand for each service or bundle that a firm may sell. We exploit these properties to examine bundling behavior when firms choose: (i) prices, and (ii) which products to sell. Using consumer-level data and survey data from the Portuguese telecommunications industry, we estimate our demand model and identify firm incentives to bundle and tie in this industry. We use the model to perform several policy related conterfactuals and evaluate their impact on prices and product provision

Utility of virus genes inhibiting the interferon response

"The African Swine Fever Virus (ASFV) is a large double-stranded DNA virus that replicates primarily in macrophages in vivo and endothelial cells in vitro. It causes a persistent infection in its natural host, the warthog, but a fulminant disease in domestic pig. Thus, it is a source of major economic losses in many African countries and a threat to pig farming worldwide. No vaccine currently exists, and therefore options for disease control are limited to destruction of infected pigs.(...)."N/

Architectural Membranes for improving the functional performance of buildings

A well designed envelope separates the interior from the exterior so that the internal conditions are maintained with the minimum energy consumption. Due to its reduced weight, architectural membrane solutions may present some functional problems, namely acoustic and hygrothermal, when compared to conventional, heavier solutions. However, they also have potential and ecological advantages that can be exploited to enable the functional optimization of existing buildings in a sustainable way, due to the minimal use of material and the fact that they are dry assembling, easily reusable and recyclable solutions. This paper presents some emergent technologies for applying architectural membranes in building envelope, revealing ways to overcome the limitations for that they are recognized. Current trends include: hybrid membranes and coatings resulting from nanotechnology solutions; membranes with embedded smart technologies (batteries, LEDs, sensors), membranes incorporating Phase Change Materials and membranes for the purification and regulation of indoor air quality. Technological innovation in this field has advanced at an extraordinary pace in the last decades and has generated solutions that in some cases present functional performance equivalent to conventional solutions, but with less environmental impact.Erasmus+. SFRH/BD/104891/201