Modelo de conhecimento para intermediários de inovação com Crowdsourcing

Tese de Doutoramento em Tecnologias e Sistemas de Informação.

Um modelo para a gestão do conhecimento organizacional no contexto dos serviços partilhados com recurso à utilização do e-Learning

Tese de Doutoramento em Tecnologias e Sistemas de Informação

Regresso ao trabalho: vivências conflituantes no exercício do papel parental

Este estudo procurou compreender as experiências das mães que regressam ao trabalho após o término da licença parental, com a finalidade de poder contribuir para a melhoria da qualidade dos cuidados de enfermagem prestados à família nesta etapa de transição no exercício da parentalidade. Foi realizado com recurso ao referencial metodológico da Grounded Theory, com a participação de cinco pais e cinco mães (casais), profissionalmente ativos, com idades compreendidas entre os 26 e 33 anos e com filho nascido de termo e saudável; recolha de dados através de entrevistas semiestruturadas (total de 30 entrevistas), antes e após o reinício da atividade laboral materna. Os resultados explanam a difícil e desafiadora coexistência de papéis desempenhados pela mulher trabalhadora quando se torna mãe e retratam o sofrimento vivido pela mãe por não poder estar constantemente com o filho ao retomar a atividade profissional, finda a licença parental. Desafiam os enfermeiros a dinamizarem estratégias que facilitem e promovam a saúde das mães trabalhadoras, com orientação antecipatória sobre as realidades do retorno ao trabalho no pós-parto.

Quantum field theory approach to the optical conductivity of strained and deformed graphene

The computation of the optical conductivity of strained and deformed graphene is discussed within the framework of quantum field theory in curved spaces. The analytical solutions of the Dirac equation in an arbitrary static background geometry for one dimensional periodic deformations are computed, together with the corresponding Dirac propagator. Analytical expressions are given for the optical conductivity of strained and deformed graphene associated with both intra and interbrand transitions. The special case of small deformations is discussed and the result compared to the prediction of the tight-binding model.

Pseudofermion dynamical theory for the spin dynamical correlation functions of the half-filled 1D Hubbard model

A modified version of the metallic-phase pseudofermion dynamical theory (PDT) of the 1D Hubbard model is introduced for the spin dynamical correlation functions of the half-filled 1D Hubbard model Mott– Hubbard phase. The Mott–Hubbard insulator phase PDT is applied to the study of the model longitudinal and transverse spin dynamical structure factors at finite magnetic field h, focusing in particular on the sin- gularities at excitation energies in the vicinity of the lower thresholds. The relation of our theoretical results to both condensed-matter and ultra-cold atom systems is discussed.

On the temperature dependence of the absorption cross section for black holes in string theory

We study the low frequency absorption cross section of spherically symmetric nonextremal d-dimensional black holes. In the presence of α′ corrections, this quantity must have an explicit dependence on the Hawking temperature of the form 1/TH. This property of the low frequency absorption cross section is shared by the D1-D5 system from type IIB superstring theory already at the classical level, without α′ corrections. We apply our formula to the simplest example, the classical d-dimensional Reissner-Nordstr¨om solution, checking that the obtained formula for the cross section has a smooth extremal limit. We also apply it for a d-dimensional Tangherlini-like solution with α′3 corrections.

Absorption of scalars by nonextremal charged black holes in string theory

We analyze the low frequency absorption cross section of minimally coupled massless scalar fields by different kinds of charged static black holes in string theory, namely the D1–D5 system in d=5 and a four dimensional dyonic four-charged black hole. In each case we show that this cross section always has the form of some parameter of the solution divided by the black hole Hawking temperature. We also verify in each case that, despite its explicit temperature dependence, such quotient is finite in the extremal limit, giving a well defined cross section. We show that this precise explicit temperature dependence also arises in the same cross section for black holes with string \alpha' corrections: it is actually induced by them.