A bounded heuristic for collection-based routing in wireless sensor networks

Wireless sensor networks are used to monitor and control physical phenomena and to provide interaction between clients and the physical environment. Clients have been typically users or user applications, but next generation wireless sensor networks will also work in machine-to-machine scenarios where some nodes can be interested in some other nodes' data. These scenarios may run the risk of becoming overloaded with messaging, a pernicious fact in particular for constrained networks where both bandwidth and power supply are limited. Resource collections can be used in wireless sensor networks to improve bandwidth usage and to reduce energy consumption, reducing the overall number of notification packets and wrapping overhead, required for the delivery of sensor data. This article proposes a heuristic algorithm for the planning of both routing and collections, in wireless sensor networks. Results show that collections are always worthwhile, and that the heuristic is able to find feasible and cost effective solutions, approaching its lower bound.FCT from Portugal within the CEOT research center [UID/MULTI/00631/2013

Quality of service in optical burst switching networks

Tese dout., Engenharia Electrónica e Computação, Universidade do Algarve, 2009Fundação para e Ciência e a Tecnologi

Bonding structure and hydrogen content in silicon nitride thin films deposited by the electron cyclotron resonance plasma method

The bonding structure and hydrogen content of amorphous hydrogenated silicon nitride (a-SiNx:H) thin films have been investigated by infrared spectroscopy and ion beam techniques. Electron cyclotron resonance plasma enhanced chemical vapor deposition was used to produce these films under different values of gas flow ratio, deposition temperature, and microwave power. The amount of bonded hydrogen was calculated from the N-H and Si-H infrared absorption bands. An increase of the SiH4 partial pressure during deposition was found to have the same effect on the H content as an increase of the substrate temperature: both cause a decrease of the N-H bond density and an increase in the number of Si-H bonds. This is explained by a competitive process in the formation of N-H and Si-H bonds during the growth of the film, whereby Si-H bonds are favored at the expense of N-H bonds when either the SiH4 flow or the substrate temperature are increased. Such tendency to chemical order is compared with previous results in which the same behavior was induced by thermal annealing or ion beam bombardment

RELOAD/CoAP P2P Overlays for Network Coding Based Constrained Environments

The Internet of Things will bring into the Internet all kinds of smart systems, which will be able to interact with each other. Therefore, applications relying on data sharing for collaboration will increase, and effective distributed solutions for data storage become necessary. This need led to the proposal of a CoAP Usage for RELOAD, a generic P2P protocol that accepts pluggable application layers (Usages). This allows P2P overlay networks to be built where constrained systems store their data and clients are able to retrieve it. Since many smart systems rely on wireless networks to communicate, where network coding can be used to reduce packet error rate, P2P overlays should be prepared to store data from network coding based networks. More specifically, encoding vectors and encoded data must be stored, and a decoding service is required. In this article, we propose a CoAP Usage extension so that network coding based constrained networks can use RELOAD/CoAP P2P distributed storage.FCT (Foundation for Science and Technology) from Portugal within CEOT Research Center [UID/MULTI/00631/2013]Thamar University - Yeme

Fast sporophyte replacement after removal suggests banks of latent microscopic stages of Laminaria Ochroleuca (phaeophyceae) in tide pools in northern Portugal

This study investigated the effects of a physical disturbance consisting of the removal of adult kelps (Laminaria ochroleuca Bachelot de la Pylaie)and their corresponding understorey turf assemblage in tide pools in northern Portugal

Presentation_1_Characterization of physiological and antioxidant responses in Run1Ren1 Vitis vinifera plants during Erysiphe necator attack.pptx

Grapevine is a fruit crop of major significance worldwide. Fungal attacks are one of the most relevant factors affecting grapevine yield and fruit quality, and powdery mildew caused by Erysiphe necator is one of the most harmful fungal diseases for this fruit-bearing species. Incorporating resistance genes such as Run1 and Ren1 in new vine selections offers a sustainable alternative to control the disease. These combined loci produce an immune response that prevents the development of the disease. However, to date studies are lacking concerning whether this response generates alterations in the physiological and antioxidant parameters of resistant plants in the presence of the fungus or if it has an associated energy cost. Therefore, the main goal of our research was to determine if Run1Ren1 plants present alterations in their physiological and biochemical parameters in the presence of the fungus. To achieve this target, a previously characterized resistant Run1Ren1 genotype and the susceptible Carménère cultivar were analyzed. We evaluated photochemical parameters (Fv’/Fm’, ΦPSII and ETR), net photosynthesis (Pn), photosynthetic pigments, transpiration (E), stomatal conductance (gs), oxidative stress parameters (MDA), antioxidant activity, and phenols. Our results show that the physiological parameters of Run1Ren1 plants were not negatively affected by the fungus at 10 days post-inoculation, contrasting with alterations observed in the susceptible plants. Therefore, we propose that the resistance response triggered by Run1Ren1 is physiologically and biochemically advantageous to grapevines by preventing the development of powdery mildew infection.</p

Causalidade e epidemiologia Causality and epidemiology

Este texto trata da questão da causalidade em epidemiologia. Começa com um breve retrospecto histórico para recuperar os diversos sentidos dados ao conceito pelos principais filósofos ocidentais. Em seguida, considera as raízes históricas da epidemiologia enquanto disciplina científica e as transformações que o conceito de causa sofreu em seu âmbito. Estabelecidas essas premissas, analisa-se o desenvolvimento da epidemiologia no século XX e a crise de paradigma que enfrenta na atualidade. Como saídas para a crise, no que se refere à questão da causalidade, examina três alternativas: a epidemiologia social, a crítica popperiana a os aportes da biologia molecular. Finalmente, comenta a necessiclade de uma nova teoria epidemiológica construída a partir da teoria da complexidade.<br>In examining the issue of causality whithin epidemiology, the text begins with a brief historical overview that reclaims the different meanings which the West's main philosophers have lent to this concept. It next delves into the historical roots of epidemiology as a scientific discipline and the transformations the concept of cause has undergone to within this realm. With these presuppositions in place, the text goes on to analyse the 20th century development of epidemiology and the crisis ít currently faces in terms of paradigm. Three alternatives are explored as ways out of this crisis: social epidemiology, Popperian criticism and the contributions of molecular biology. Lastly, the tent discusses the need for a new epidemiological theory grounded on the theory of complexity