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Browsing by Issue Date, starting with "2017-08"

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  • Newborns Safety at Neonatal Intensive Care Units: Are they Exposed to Excessive Noise during Routine Health Care Procedures?
    Publication . Alberto Alves Carvalhais, Carlos; Vieira Da Silva, Manuela; Xavier, Ana; Santos, Joana
    Neonatal Intensive Care Unit (NICU) noise may be stressful to preterm infants. This research evaluated the newborns exposure to noise during several health care activities of two NICU. The measurements of the equivalent continuous A-weighted sound pressure level and peak sound pressure level were carried were performed with a sound level meter, as close as possible of the newborn. The results showed that sound pressure levels were excessive in all the evaluated tasks, exceeding international guidelines. The levels ranged between 46.6 dBA to 74.6 dBA. There is a need for more research in order to verify the effectiveness of specific strategies to reduce the impact of noise in NICU.
    2017-08Journal article Open access Show more
  • Dynamic Pricing for Demand Response Considering Market Price Uncertainty
    Publication . Fotouhi Ghazvini, Mohammad; Soares, João; Morais, Hugo; Castro, Rui; Vale, Zita
    Retail energy providers (REPs) can employ different strategies such as offering demand response (DR) programs, participating in bilateral contracts, and employing self-generation distributed generation (DG) units to avoid financial losses in the volatile electricity markets. In this paper, the problem of setting dynamic retail sales price by a REP is addressed with a robust optimization technique. In the proposed model, the REP offers price-based DR programs while it faces uncertainties in the wholesale market price. The main contribution of this paper is using a robust optimization approach for setting the short-term dynamic retail rates for an asset-light REP.With this approach, the REP can decide how to participate in forward contracts and call options. They can also determine the optimal operation of the self-generation DG units. Several case studies have been carried out for a REP with 10,679 residential consumers. The deterministic approach and its robust counterpart are used to solve the problem. The results show that, with a slight decrease in the expected payoff, the REP can effectively protect itself against price variations. Offering time-variable retail rates also can increase the expected profit of the REPs.
    2017-08Journal article Open access Show more
  • Analysis and quantification of damage in polymer composite materials
    Publication . Durão, Luís Miguel; Matos, João E.; Silva, Pedro
    The specific characteristics of composite materials, like carbon fibre reinforced plastics, have been leading to their rising importance and widespread use. As these parts are normally produced in a nearnet shape, secondary operations, like drilling, are necessary prior to their assembly in complex structures. It is still difficult to define a machining process that enables free damage holes, due to the peculiar laminar nature of these materials. So, the definition of a drilling process that minimizes delamination and increases reliability in produced parts combined with satisfactory cost and productivity is still of major importance in the composites manufacturing industry. In this paper two sets of unidirectional coupons from plates with carbon fibre as reinforcement and epoxy resin as matrix, are drilled using five different drilling tool strategies and two feed rates for uneven damage extension. One of the strategies is the use of a pre-drilling option. Then the delamination is assessed using enhanced radiography and, finally, two diverse mechanical tests are performed on the resulting coupons: three point bending and pin bearing. The results allowed establishing and modelling, with the help of statistical tools, the relations between the damaged area caused by drilling and the material’s mechanical resistance. The bending resistance does not vary greatly with the damage area. On the other hand, the bearing resistance decreases with the increase of the damaged area.
    2017-08Conference object Open access Show more
  • Sistema endocanabinoide y sus efectos en el SNC
    Publication . Pastrana-Trejo Carlos, José; Macías-Triana, Lorena; Romero-Cordero, Karen; Daniela Soriano-Nava, Marcia; Morales-Lara, Daniela; Rocha, Nuno; Barciela Veras, André; Henning, Budde; Machado, Sérgio; Murillo-Rodríguez, Eric
    Los canabinoides endógenos o endocanabinoides son un grupo de moléculas producidas por el sistema nervioso central (SNC), las cuales ejercen efectos muy parecidos a los canabinoides exógenos. Entre los endocanabinoides más estudiados, tenemos a los lípidos anandamida (ANA), y el 2-araquidonoilglicerol (2-AG). Estas moléculas forman parte del complejo sistema de endocanabinoides, el cual incluye a proteínas transmembranales denominadas, receptores para cannabinoides CB1 y CB2. Adicionalmente, el sistema de endocanabinoides está integrado por enzimas responsables de la hidrólisis de ANA y 2-AG, tales como la fatty acid amyde hydrolase (FAAH) y monoacylglycerol lipase (MAGL), así como del transportador membranal de anandamida. Múltiples evidencias experimentales y preclínicas, han demostrado que el sistema de endocanabinoides, regula diversos fenómenos neurobiológicos, tales como enfermedades neurodegenerativas, obesidad, aprendizaje y memoria, así como el ciclo sueño-vigilia. El estudio de las propiedades neurobiológicas del sistema de canabinoides endógenos, permitirá en un futuro no muy lejano, considerar a dicho sistema, como parte importante del diseño de terapias dirigidas para la prevención, y control de múltiples patologías, incluidas la enfermedad de Alzheimer, obesidad, o trastornos del sueño.
    2017-08Conference object Open access Show more
  • Caregivers’ education vs rhinopharyngeal clearance in children with upper respiratory infections: impact on children’s health outcomes
    Publication . Alexandrino, Ana Silva; Santos, Rita; Melo, Cristina; Mesquita Bastos, José; Postiaux, Guy
    Upper Respiratory Tract Infections (URTI) are very common in children having no effective pharmacological treatment. This study aimed to compare the effect of caregivers’ health education regarding children’s respiratory infections and the effect of a rhinopharyngeal clearance protocol in children with URTI. A factorial trial was conducted in 138 children up to 3 years, attending day-care centres. Children were distributed into four groups: control group (CG) (n = 38); education group (EG) (n = 34); intervention group (IG) (n = 35); and education and intervention group (E + IG) (n = 31). A Diary of Records was kept by caregivers during 1 month. There were significant differences between groups concerning: Lower Respiratory Tract Infections (CG = 29.4%; EG = 10.7%; IG = 3.8%; E + IG = 0.0%; p = 0.014); acute otitis media (CG = 32.4%; EG = 7.1%; IG = 11.5%; E + IG = 7.7%; p = 0.014); medical consultations (CG = 70.6%; EG = 42.9%; IG = 38.5%; E + IG = 30.8%; p = 0.021); antibiotics (CG = 44.1%; EG = 7.1%; IG = 23.1%; E + IG = 15.4%; p = 0.006); days missed from day-care (CG = 55 days; EG = 22 days; IG = 14 days; E + IG = 6 days; p = 0.020); days missed from employment (CG = 31 days; EG = 20 days; IG = 5 days; E + IG = 1 day; p = 0.021); and nasal clearance techniques (CG = 41.4%; EG = 78.6%; IG = 57.7%; E + IG = 84.6%; p = 0.011).
    2017-08-28Journal article Open access Show more