Browsing by Issue Date, starting with "2015-09"
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- Do Santo Desejo de uma "Boa Morte"Publication . Rosa, José Maria SilvaPara começar, proponho que não tenhamos medo das palavras. Boa morte diz-se em grego «eutanasía» = morte doce, morte bela, pacífica, fácil, sem dor, sem sofrimento, sem o pavor do trespasse, etc., que designa precisamente a «distanasía» = a distanásia, a má morte. Este desejo de «eutanasía», que as gregos trouxeram à consciência e à linguagem, é um das desejos mais arreigados na humanidade e em cada um de nós: ter uma boa morte.
- Giving sense and making choices: supporting ethnographic and discursive approach to the newsPublication . Correia, João CarlosThe need to direct our attention to different events in a permanent flow is the reverse of the ambition of universality that motivates journalism. Journalists cannot turn their attention to all events as if they all have the same relevance. Frames and typifications are procedures used by professionals to establish the relevance of issues. However, this relative relevance is, often, established at the expense of diversity and openness. We stand for a research project in journalism studies, drawing on plural contributions (Discourse Analysis Phenomenology, Interactionism and Ethnography) that help professionals to produce an inclusive news reporting
- Experimental Characterization of WSNs Applied to Swarms of Aquatic Surface DronesPublication . Velez, Fernando J.; Nadziejko, Aleksandra K. N.; Christensen, Andersen; Oliveira, Sancho; Rodrigues, Tiago; Costa, Vasco; Duarte, Miguel; Silva, Fernando; Gomes, JorgeANCAD project aims at developing technologies and communication protocols for swarms of aquatic inexpensive surface drones. The goal is to perform maritime tasks such as sea border patrolling or environmental monitoring, keeping the cost of the drones low. The exchange of information within the swarm is essential for the success of the mission. The most recent solution for control and communications within the current prototypes are supported by Raspberry Pi 2 and XBee-PRO S1 allowing for low power consumption while expanding the range of transmission. Field trial results enabled to verify the potential of the proposed solution, in terms of coverage range and multi-hop capabilities, in actual maritime scenarios.
- Wireless Sensor and Networking Technologies for Swarms of Aquatic Surface DronesPublication . Velez, Fernando J.; Nadziejko, Aleksandra; Christensen, Anders Lyhne; Oliveira, Sancho; Rodrigues, Tiago; Costa, Vasco; Duarte, Miguel; Silva, Fernando; Gomes, JorgeIn this paper, we discuss wireless sensor and networking technologies for swarms of inexpensive aquatic surface drones in the context of the HANCAD project. The goal is to enable the swarm to perform maritime tasks such as sea-border patrolling and environmental monitoring, while keeping the cost of each drone low. Communication between drones is essential for the success of the project. Preliminary experiments show that XBee modules are promising for energy efficient multi-hop drone-to-drone communication.
- Fundamental Limits for LTE Radio and Network PlanningPublication . Velez, Fernando J.; Acevedo Flores, Jessica; Robalo, DanielA comprehensive study on the variation of the carrier-to-noise-plus-interference ratio (CNIR) with different system parameters is of fundamental importance in the context of LTE planning. For cellular planning purposes, the UL and DL CNIRs from/at the mobile station are very important parameters, although we are only considering DL in this work. From a detailed analysis of its variation with the coverage and reuse distances for different modulation and coding schemes (MCS) and given empirical propagation models, an evaluation of the possible range for the reuse pattern is performed. By considering the CQI and reference CNIR requirements recommended by 3GPP. DL peak bit rates along with the Transport Block Size (TBS) assumed for single stream and bandwidth of 5 MHz, physical and supported throughputs are analysed. These formulations shows the clear decrease of the supported throughput for the longest coverage distances in the LTE 2.6 GHz band, a behaviour that is not so clear at 800 MHz, and gives hints to the optimization of the use of different frequency bands in the optimization of carrier aggregation between two different bands in LTE-A scenarios.
- Generalized LUI Propagation Model for UAVs Communications Using Terrestrial Cellular NetworksPublication . Tavares, Tiago; Sebastião, Pedro; Souto, N.; Velez, Fernando J.; Cercas, Francisco; Ribeiro, Marco; Correia, AmericoThis work proposes an empirical propagation model to obtain the path loss, and therefore determine the average received power, of a signal for a specific outdoor urban scenario with UAVs. The proposed 3D propagation model for terrestrial cellular networks generalizes the LUI model and is valid in the frequency ranges from GSM, UMTS and LTE technologies. We report experimental work in 3D space, considering the height, the antennas base station tilt, sectorization, angle and distances profile. The experimental work included in this study appropriately agrees with the proposed theoretical model; hence, the proposed model is adequate for cellular planning tools.
- Scenarios and Architectures for RRM and Optimization of Heterogenous NetworksPublication . Sousa, Sofia C.; Velez, Fernando J.; Huq, Kazi; Mumtaz, Shahid; Rodrigues, JonathanThis work summarizes the state of the art information related to scenarios and architectures from Energy-efficient High-speed Cost Effective Cooperative Backhaul for LTE/LTE-A Small-cells (E-COOP) technologies. One of the proposed architectures exploits infrastructure based on small cell deployment using RRU technology which is connected to the core network using backhaul technology based on fibre optic links. In E-COOP, we go beyond this by addressing four key scenarios in terms of fronthaul deployment strategy (scenario 1) for C-RAN and carrier aggregation (scenario 2). The third scenario exploits the C-RAN architecture to firstly split the control/ data plane where the macro base station improves the signalling service for the whole area. Also, mobile small cells (SCs) are cooperatively specialized towards delivering data services for high-rate transmission with light overhead control and appropriate air interface (mmWave) – scenario 3. This raises significant research challenges in terms of mobile small cell coexistence, and mobility management. In scenario 4, we consider SON in LTE-A for HetNets with ultra-dense small cell deployment with imperfect backhaul. A Primary Network is considered that is overlaid with a cognitive network of Small Cell Networks, performing local sensing and local self-configuration and -optimization algorithms.
- 5α-Dihydrotestosterone regulates the expression of L-type calcium channels and calcium-binding protein regucalcin in human breast cancer cells with suppression of cell growthPublication . Marques, Ricardo; Peres, Carina; Vaz, Cátia; Gomes, Inês; Figueira, Marília I; Cairrão, Elisa; Verde, Ignacio; Baptista, Cláudio; Socorro, SílviaAndrogens have been associated with the development of normal breast, and their role in mammary gland carcinogenesis has also been described. Several studies reported that androgens inhibit breast cancer cell growth, whereas others linked their action with the modulation of calcium (Ca(2+)) pumps, Ca(2+) channels and Ca(2+)-binding proteins. Also, it is known that deregulated Ca(2+) homeostasis has been implicated in the pathophysiology of breast. The L-type Ca(2+) channels (LTCCs) were found to be up-regulated in colon, colorectal and prostate cancer, but their presence in breast tissues remains uncharacterized. On the other hand, regucalcin (RGN) is a Ca(2+)-binding protein involved in the control of mammary gland cell proliferation, which has been identified as an androgen target gene in distinct tissues except breast. This study aimed to confirm the expression and activity of LTCCs in human breast cancer cells and investigate the effect of androgens in regulating the expression of α1C subunit (Cav1.2) of LTCCs and Ca(2+)-binding protein RGN. PCR, Western blot, immunofluorescence and electrophysiological experiments demonstrated the expression and activity of Cav1.2 subunit in MCF-7 cells. The MCF-7 cells were treated with 1, 10 or 100 nM of 5α-dihydrotestosterone (DHT) for 24-72 h. The obtained results showed that 1 nM DHT up-regulated the expression of Cav1.2 subunit while diminishing RGN protein levels, which was underpinned by reduced cell viability. These findings first confirmed the presence of LTCCs in breast cancer cells and opened new perspectives for the development of therapeutic approaches targeting Ca(2+) signaling.
- Enhanced Microfluidic Mixing via a Tricritical Spiral Vortex InstabilityPublication . Haward, Simon J.; Poole, R. J.; Alves, M. A.; Oliveira, Paulo J.; Goldenfeld, Nigel; Shen, Amy Q.Experimental measurements and numerical simulations are made on fluid flow through cross-slot devices with a range of aspect (depth:width) ratios, 0.4 < alpha < 3.87. For low Reynolds numbers Re, the flow is symmetric and a sharp boundary exists between fluid streams entering the cross-slot from opposite directions. Above an alpha-dependent critical value Re_c, the flow undergoes a symmetry-breaking bifurcation (though remains steady and laminar) and a spiral vortex structure develops about the central axis of the outflow channel. An order parameter characterizing the instability grows according to a sixth-order Landau potential, and shows a progression from second order to first order transitions as alpha increases. A tricritical point occurs for alpha ~ 0.55. The spiral vortex acts as a mixing region in the flow field and this phenomenon can be used to drive enhanced mixing in microfluidic devices.
- Urban water reuse in tourism areaPublication . Albuquerque, António; Matos, J.Over the past decades, treated wastewater (reclaimed water) has been used as an alternative to potable water for a range of uses such as irrigation (landscapes, golf courses, and agricultural fields), aquifer recharge, industry applications, stream flow feed- ing, and nonpotable urban applications. In that period, there have been significant advances in reuse technologies, and an increase in the implementation of either rules or guidelines for water reuse. Tourism generates one of the biggest pressures on water needs that coincides with the necessity to manage decreasing water resources more efficiently. As tourism areas continue to grow, pressure on local water sources will continue to increase and significant environmental, economic, and social impacts can arise where local freshwater supplies are limited or are available only with large capital investment. The integration of water reuse in water management strategies will contribute to reducing discharges to receiving waters and reducing reliance on natural water sources to meet water demands. In tourism areas, there are several opportunities for reusing reclaimed water produced from domestic wastewater, stormwater, and graywater. Urban waters can be treated through a variety of physical, chemical, and biological processes in order to produce final reclaimed water for dis- charging into a water stream or for reuse.