180 research outputs found

    Design of a learning environment for embedded system

    Get PDF
    Embedded systems have an everyday presence and direct impact in our lives. Therefore, Universities are continuously improving their courses in microprocessor and embedded programming. Although the diversity of curriculums, the availability of learning tools, where the student can practice and improve their skills, is a key factor to the success of the learning process. The platform developed and presented in this paper results from author’s experience in teaching embedded systems. From the analysis of teaching/learning needs, a learning environment based on the MSP430 family was designed. This tool can be expanded by modules and adjusted, at a specific time, to student's real needs. All modules can be interconnected by an I2C bus, allowing to expand the capabilities of the platform. The developed modules allow the practice of subjects related with digital IO, analog interface, user interface, wireless communications, and energy management and conservation.info:eu-repo/semantics/publishedVersio

    VALIDATION WITH VIDEOMETRY OF AN INTEGRATED SYSTEM TO ASSESS HORIZONTAL INTRA-CYCLIC VELOCITY WITH A MECHANICAL SPEED-METER

    Get PDF
    The aim of this paper was to: validate an integrated system (i.e., software application and hardware after calibration) to assess human‟s horizontal intra-cyclic velocity with a mechanical speedo-meter. System validation was done for a set of land-based human locomotion techniques (from slow walk to maximal running) in four subjects and comparing it with a videometric system (i.e. APAS). There were no significant differences between pair wise data (speedo-meter versus APAS data) using student„s t-test for both velocity coefficient of variation and maximal velocity. Linear regression models were very high for both the velocity coefficient of variation and maximal velocity. More than 80% of the Bland-Altman plots were within 1.96 standard-deviations

    so much work, so many lost opportunities

    Get PDF
    Mainoli, B., Machado, T., Duarte, G. S., Prada, L., Gonçalves, N., Ferreira, J. J., & Costa, J. (2021). Analysis of clinical and methodological characteristics of early COVID-19 treatment clinical trials: so much work, so many lost opportunities. BMC Medical Research Methodology, 21(1), 1-10. [42]. https://doi.org/10.1186/s12874-021-01233-wBackground: The COVID-19 pandemic continues to rage on, and clinical research has been promoted worldwide. We aimed to assess the clinical and methodological characteristics of treatment clinical trials that have been set forth as an early response to the COVID-19 pandemic. Methods: First, we reviewed all registered clinical trials on COVID-19. The World Health Organization International Trials Registry Platform and national trial registries were searched for COVID-19 trials through April 19th, 2020. For each record, independent researchers extracted interventions, participants, and methodological characteristics. Second, on September 14th, 2020 we evaluated the recruitment status and availability of the results of COVID-19 treatment trials previously identified. Results: In April 2020, a total of 580 trials evaluating COVID-19 treatment were registered. Reporting quality was poor (core participant information was missing in 24.1 to 92.7%). Between 54.0 and 93.8% of the trials did not plan to include older people or those with a higher baseline risk. Most studies were randomised (67.9%), single-centre (58.3%), non-industry-funded (81.1%), to be conducted in China (47.6%), with a median duration of 184 days and a median sample size of 100 participants. Core endpoints (mortality, clinical status, and hospitalization length) were planned to be assessed in 5.2 to 13.1% of the trials. Five months later, 66 trials (11.4%) were reported as “Completed”, and only 46 (7.9%) had public results available. One hundred forty-four of 580 trials (24.8%) either had the status “Not yet recruiting” or “Suspended”, and 18 (3.1%) trials were prematurely stopped (“Terminated” or “Withdrawn”) The number of completed trials and trials with results are much lower than anticipated, considering the planned follow-up. Conclusions: Our results raise concerns about the success of the initial global research effort on COVID-19 treatment. The clinical and methodological characteristics of early COVID-19 treatment trials limit their capability to produce clear answers to critical questions in the shortest possible time.publishersversionpublishe

    An experimental investigation on nano-TiO2 and fly ash based high performance concrete

    Get PDF
    High performance concrete (HPC) offers several advantages over normal-strength concrete, namely, high mechanical strength and high durability. Therefore, HPC allows for concrete structures with less steel reinforcement and a longer service life, both of which are crucial issues in the eco-efficiency of construction materials. Nevertheless international publications on the field of concrete containing nanoparticles are scarce when compared to Portland cement concrete (around 1%) of the total international publications. HPC nanoparticle-based publications are even scarcer. This article presents the results of an experimental investigation on the mechanical properties and durability of HPC based on nano-TiO2 and fly ash. The durability performance was assessed by means of water absorption by immersion, water absorption by capillarity, ultrasonic pulse velocity, electric resistivity, chloride diffusion and resistance to sulphuric acid attack. The results show that the concretes containing an increased content of nano-TiO2 show decreased durability performance. The results also show that concrete with 1% nano-TiO2 and 30% fly ash as Portland cement replacement show a high mechanical strength (C55/C67) and a high durability. However, it should be noted that the cost of nano-TiO2 is responsible for a severe increase in the cost of concrete mixtures.(undefined

    A design of experiments (DoE) approach to optimize cryogel manufacturing for tissue engineering applications

    Get PDF
    Marine origin polymers represent a sustainable and natural alternative to mammal counterparts regarding the biomedical application due to their similarities with proteins and polysaccharides present in extracellular matrix (ECM) in humans and can reduce the risks associated with zoonosis and overcoming social- and religious-related constraints. In particular, collagen-based biomaterials have been widely explored in tissue engineering scaffolding applications, where cryogels are of particular interest as low temperature avoids protein denaturation. However, little is known about the influence of the parameters regarding their behavior, i.e., how they can influence each other toward improving their physical and chemical properties. Factorial design of experiments (DoE) and response surface methodology (RSM) emerge as tools to overcome these difficulties, which are statistical tools to find the most influential parameter and optimize processes. In this work, we hypothesized that a design of experiments (DoE) model would be able to support the optimization of the collagen-chitosan-fucoidan cryogel manufacturing. Therefore, the parameters temperature (A), collagen concentration (B), and fucoidan concentration (C) were carefully considered to be applied to the Boxâ Behnken design (three factors and three levels). Data obtained on rheological oscillatory measurements, as well as on the evaluation of antioxidant concentration and adenosine triphosphate (ATP) concentration, showed that fucoidan concentration could significantly influence collagen-chitosan-fucoidan cryogel formation, creating a stable internal polymeric network promoted by ionic crosslinking bonds. Additionally, the effect of temperature significantly contributed to rheological oscillatory properties. Overall, the condition that allowed us to have better results, from an optimization point of view according to the DoE, were the gels produced at −80ºC and composed of 5% of collagen, 3% of chitosan, and 10% fucoidan. Therefore, the proposed DoE model was considered suitable for predicting the best parameter combinations needed to develop these cryogels.This research was funded by the Portuguese Foundation for Science and Technology (FCT) for Ph.D. fellowship (D.N.C.) under the scope of the doctoral program Tissue Engineering, Regenerative Medicine and Stem Cells, ref. PD/BD/143044/2018, for postdoctoral fellowship (C.G.), ref. SFRH/BPD/94277/2013. This work has been partially funded by ERDF under the scope of the Atlantic Area Program through project EAPA_151/2016 (BLUEHUMAN)

    The narrative model of therapeutic change: an exploratory study tracking innovative moments and protonarratives using state space grids

    Get PDF
    Despite the popularity of narrative approaches to the change in psychotherapy, a better understanding of how narrative transformation facilitates therapeutic change is needed. Research on innovative moments (IMs) has explored how IMs in psychotherapy evolve over time. We expand on past studies by exploring how IMs become aggregated in narrative threads, termed protonarratives, which come to constitute an alternative self-narrative at the conclusion of therapy. The results suggest that the good outcome case had a different pattern of IM integration within protonarratives, revealing greater flexibility than the poor outcome case. These results support the heuristic value of the concept of the protonarrative

    Time limit at the minimum velocity of VO2max and intracyclic variation of the velocity of the centre of mass

    Get PDF
    The purpose of this study was to analyse the relationship between time limit at the minimum velocity that elicits maximal oxygen consumption (TLim-vVO2max) and intra-cyclic variations of the velocity of the centre of mass (dv) in the four competitive swimming techniques. Twelve elite male swimmers SWIMMING BIOENERGETICS Rev Port Cien Desp 190 6(Supl.2) 185–197 swam their own best technique until exhaustion at their previously determined v O2max to assess TLim-v O2max. The test was videotaped in the sagittal plan and the APAS software was used to evaluate the horizontal velocity of the centre of mass (Vcm) and its intra-cyclic variation (dv) per swimming technique. Results pointed out that the strokes that presented higher intra-cyclic variations also presented larger values of TLim. Intra-cyclic speed fluctuations (dv) decreased during the TLim test in the four strokes studied, probably due to fatigue. Key words: VO2, intra-cyclic velocity variations, time limit, centre of mass.Authors want to express their gratitude to the Portuguese National Team, and the Portuguese Swimming Federation, for their cooperation
    corecore