The Jacobi identity for Dirac-like brackets

For redundant second-class constraints the Dirac brackets cannot be defined and new brackets must be introduced. We prove here that the Jacobi identity for the new brackets must hold on the surface of the second-class constraints. In order to illustrate our proof we work out explicitly the cases of a fractional spin particle in 2+1 dimensions and the original Brink-Schwarz massless superparticle in D=10 dimensions in a Lorentz covariant constraints separation.Comment: 14 pages, Latex. Final version to be published in Int. J. Mod. Phys.

Clinical studies of breathing during sleep and sudden infant death syndrome

The primary aim of the research reported in this thesis was to study breathing patterns during sleep in a) apparently normal symptom-free full-term infants, b) infants admitted to hospital during and following recovery from relatively minor illnesses, and c] infants thought to be at increased risk for Sudden Infant Death Syndrome CSIDS) - siblings of previous SIDS victims, and 'near-miss' for SIDS cases, to quantify apnoea (central and obstructive] and observe its effect on heart rate and transcutaneous oxygen tension, PtcO₂. Secondary aims were to study gross body movements (as an indicator of arousal], and to assess whether infants at 'increased risk' for SIDS were chronicallyhypoxaemic during the early months of life. Polysomniographic studies lasting three to five hours during the night recorded eye movements, digastric muscle tone, electrocardiogram^, electroencephalogram, airflow, chest and abdominal movements and PtcO₂ in 86 index cases and 11 healthy controls studied on 176 and 31 occasions respectively.The results were as follows:1. The 11 normal healthy infants did not have episodes of obstructive or prolonged (^-15 seconds] central apnoea during sleep.2. 33 'symptomatic' infants revealed: a] Bronchiolitis - apnoeic pauses were shorter than 15 seconds. Indices of central apnoea were increased significantly in quiet sleep during the index illness. Prolonged (≥ 6 seconds) obstructive apnoea was uncommon

What are the effects of mass retailers on Lisbon’s municipal markets?

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and EconomicsThe primary purpose of this research is to analyze the impact of mass retailers on Municipal Markets in the city of Lisboa between 2004 and 2009. A Prais-Winsten regression with specific panel AR(1) and PCSEs was used to estimate the model. The findings reveal that, on average, an increase of 1 supermarket per km2 within the “Freguesia” where the municipal market is located leads to a decrease of 3.48% in the occupation rates while an increase of 0.1 hypermarkets per km2 leads to a decrease of 5.62% if it is located within the “Freguesia” and of 10.10% if it is located in the adjacent ones

Positive solutions to find a job: cultural mismatches between companies and employees

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and EconomicsPsychology is not just the study of disease, weakness, and damage; it also is the study of strength and virtue (Seligman & Csikszentmihalyi, 2000). Attempts to change this thinking school is the theory of Positive Psychology from Seligman which is the base for this dissertation. The methodology used in our model followed the hypothesis testing in order to assess the veracity of positive behaviors affecting the outcome of finding a job. Therefore, through the use of Logistic Regressions, several results proved that positive behaviors such as optimism are indeed affecting the way we apply to a job and how satisfied we are with it. Thus, since each country presents a different set of cultural behaviors such as the level of optimism and self-determination, companies and education systems that are internationalizing should concern cultural impacts and maybe mind about cultural teachings to local workers to improve their adaptation to the institution. The models studied in this dissertation should be tested again with different samples in order to bring more consistency to this subject

Model-driven GUI generation and navigation for android BIS apps

This paper presents our approach for producing graphical user interfaces (GUIs) for functionally rich business information system (BIS) prototypes, upon a mobile platform. Those prototypes are specified with annotated UML class diagrams. Navigation in the generated GUIs is allowed through the semantic links that match the associations and cardinalities among the conceptual domain entities, as expressed in the model. We start by reviewing the Android scaffolding for producing flexible GUIs for mobile devices. The latter can present rather different displays, in terms of size, orientation and resolution. Then we show how our model-based generative technique allows producing prototypes that match both the Android GUIs requirements, while implementing our model-driven approach for user navigation.info:eu-repo/semantics/publishedVersio

The Portuguese High Speed Rail Network; Relating Financing to Strategic and Operating Issues

This paper describes the implementation of the Portuguese High Speed Rail (HSR) Network. The business model developed by RAVE for the PPP’s related with the HSR infrastructure is described and discussed. Following a recently awarded research project (EXPRESS) aimed at studying the strategic aspects related with the implementation of HSR is presented and its aspects more directly related with HSR operation which could be relevant in a PPP context are discussed

An investigation into the influence of land-use, social networks and information and communication technologies on destination choice for social activities

Information and Communication Technologies (ICT) enable individuals to travel more flexibly. The choice of location for social activities has become very flexible. In addition to this, land-use characteristics also play a vital role in the location of social activities. This work aims to analyse the influence of land-use characteristics, ICT use, and social networks in the destination choices for face-to-face social activities of university students during both weekdays and weekends. Students from the two different campuses of the Instituto Superior Técnico were presented with an online questionnaire, which was intended to collect information about their use of ICT and social networks, in addition to their travel characteristics and socio-demographics. Emphasis was made upon capturing the characteristics of social networks and ICT usage. Information on land-use characteristics was obtained from secondary sources. Factor analysis was initially carried out to extract factors related to the use of ICT and social networks; these were later used to model the destination choice for social activities. The alternatives considered for destination choice included: home or the vicinity thereof, university or the vicinity thereof, other locations (further away from home and university), and evenly spread locations – having no specific priority for any of the other three locations considered. The analysis was performed separately for travel during weekdays and weekends so that an understanding of the differences and similarities in behaviour during these different time periods could be garnered. A multinomial logit model was estimated to model this choice. The results point to the relevance of land-use characteristics, the location of close friends, and modes of interaction. Individuals residing in more accessible central, and denser areas, were more likely to have activities distributed evenly across the city. These results stress the relevance of accessibility in allowing larger and more diverse spaces to be used for social activities