Avaliação da usabilidade e da acessibilidade do site de matemática : RPEDU

Um site de apoio à disciplina pode ajudar a motivar os alunos a aprender online. No entanto não se podem descurar alguns aspectos que podem comprometer a sua aceitação. Neste artigo descrevemos o conjunto de testes realizados ao site RPEDU, Matemática para alunos do 3.º ciclo, de forma a potenciar a sua aceitação junto do público-alvo. Nesse sentido procedeu-se à avaliação heurística, à avaliação da acessibilidade e à condução de testes de usabilidade com utilizadores. Os resultados obtidos implicaram algumas reformulações que se apresentam.Fundação para a Ciência e a Tecnologia (FCT

Nonparametric latency estimation for mixture cure models

This version of the article has been accepted for publication, after peer review and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: https://doi.org/10.1007/s11749-016-0515-1[Abstract]: A nonparametric latency estimator for mixture cure models is studied in this paper. An i.i.d. representation is obtained, the asymptotic mean squared error of the latency estimator is found, and its asymptotic normality is proven. A bootstrap bandwidth selection method is introduced and its efficiency is evaluated in a simulation study. The proposed methods are applied to a dataset of colorectal cancer patients in the University Hospital of A Coruña (CHUAC).The first author’s research was sponsored by the Spanish FPU (Formación de Profesorado Universitario) Grant from MECD (Ministerio de Educación, Cultura y Deporte) with reference FPU13/01371. All the authors acknowledge partial support by the MINECO (Ministerio de Economía y Competitividad) grant MTM2014-52876-R (EU ERDF support included), the MICINN (Ministerio de Ciencia e Innovación) Grant MTM2011-22392 (EU ERDF support included) and Xunta de Galicia GRC Grant CN2012/130. The authors are grateful to Dr. Sonia Pértega and Dr. Salvador Pita, at the University Hospital of A Coruña, for providing the colorectal cancer data set.Xunta de Galicia; CN2012/13

Integrated sizing and scheduling of wind/PV/diesel/battery isolated systems

In this paper we address the optimal sizing and scheduling of isolated hybrid systems using an optimization framework. The hybrid system features wind and photovoltaic conversion systems, batteries and diesel backup generators to supply electricity demand. A Mixed-Integer Linear Programming formulation is used to model system behavior over a time horizon of one year, considering hourly changes in both the availability of renewable resources and energy demand. The optimal solution is achieved with respect to the minimization of the levelized cost of energy (LCOE) over a lifetime of 20 years. Results for a case study show that the most economical solution features all four postulated subsystems

Atmosphere assisted FLASH sintering of KNN

The use of FLASH alternative sintering technique allows a significant decrease in sintering time and temperature, contributing to the sustainable processing of high sintering temperature piezoelectrics. This is the case of potassium sodium niobate, K0.5Na0.5NbO3 (KNN), a relevant lead-free piezoelectric, which, due to alkali evaporation, is difficult to produce by conventional sintering, at T \u3e 1100 ºC. Please click Additional Files below to see the full abstract

Dielectric behavior of FLASH sintered KNN

The market for lead-based piezoceramics, mainly (Pb1-x ZrxTiO3, PZT) - based materials, is higher than $100 billion per year. Due to lead-toxicity, the demand for lead-free piezoceramics is increasing. Potassium Sodium Niobate solid solutions, namely K0.5Na0.5NbO3, KNN, is currently one of the most promising materials for electromechanical applications. However, monophasic conventionally sintered KNN is hard to obtain, due to alkali evaporation during sintering (T\u3e 1100 ºC, t \u3e 2h). Within this context, there is an increasing interest in sustainable sintering techniques, as FLASH, to decrease both sintering time and temperature, avoiding alkali vaporization. However, FLASH applied to bulk ceramics, frequently produces inhomogeneous specimens. Figure 1 – Variation of length with temperature of FLASH sintered KNN, after a 2 h isothermal step. SEM micrograph showing the uniformly dense microstructure. In this work, we propose an experimental approach that allows the production of homogeneous, highly dense, KNN. In this method, the use of FLASH sintering contributed to reduce KNN sintering temperature for more than 200 ºC and the cycle time in ~3h. Uniform densification was achieved by using an isothermal step before the application of the electric field. Scanning Electron Microscopy (SEM) and Specific Surface Area (SSA) measurements were performed to characterize the pre-FLASH sintering microstructure. Please click Additional Files below to see the full abstract

A proof-of-concept

Funding Information: C. Costa, T. Casimiro and A. Aguiar-Ricardo are grateful for the financial support of the Associate Laboratory for Green Chemistry-LAQV, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa , Portugal, which is financed by national funds from FCT/MCTES ( UIDB/50006/2020 and UIDP/50006/2020 ). C. Costa thanks FCT (Fundação para a Ciência e Tecnologia) and ESF (European Social Fund) through POCH (Programa Operacional Capital Humano) for her PhD grant ref. PD/BD/142880/2018, COVID/BD/152744/2022 and Project PD/00184/2012-PDQS . C. Costa and A. Aguiar-Ricardo acknowledge also CA18224 GREENERING (“Green Chemical Engineering Network towards upscaling sustainable processes”). COST Actions are funded within the EU Horizon 2020 Programme . M.L. Corvo is grateful for the financial support of the Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa , Lisbon, Portugal, which is supported in part by UID/DTP/04138/2020 and UIDP/04138/2020 from FCT/MCTES , Portugal. The authors are grateful to Prof. M. Dionísio for the DSC facility. Publisher Copyright: © 2023Enzyme-based inhalable therapeutics for lung inflammation are gaining interest as an alternative to long-term corticosteroids treatments. However, enzymes have poor pharmacokinetics. Encapsulating enzymes in liposomes can increase their half-live and modify their biodistribution. But both liposomes and enzymes are susceptible to destabilization during storage. This drawback can be surpassed, by converting liposomal suspension into solid dosage forms for different administration routes, including inhalation. In this study, Cu, Zn- superoxide dismutase (SOD) was encapsulated in liposomes, then dried using supercritical CO2-assisted spray-drying to make SOD-loaded liposomal dry powder formulations (SOD_Lip-DPFs). Upon resuspension in water, liposomes maintained structural integrity, with 99% SOD encapsulation efficiency and preserved enzymatic activity. Stability studies showed that SOD_Lip-DPFs maintained liposomal and enzyme stability for 50 days at 40% relative humidity. This offers a stable and efficient delivery system for enzyme-based inhalable therapeutics.publishersversionpublishe

Halophyte plants from sustainable marine aquaponics are a valuable source of omega-3 polar lipids

Marine aquaponics is a promising sustainable approach for the production of profitable crops such as halophytes. However, the effect of this culture approach on the lipid composition of halophytes remains unknown. In this work, we contrasted the polar lipidome of Salicornia ramosissima and Halimione portulacoides when produced in marine aquaponics (effluent from a super-intensive flatfish aquaculture production), with that of conspecifics from donor wild populations. Phospholipids and glycolipids were identified and quantified by LC-MS and MS/MS and their profile statistically analysed. Halophytes produced in aquaponics have higher levels of glycolipids with n-3 fatty acids (DGDG 36:3; SQDG 36:3; MGDG 36:6) compared with the donor wild populations. In the case of H. portulacoides, a significant increase of phospholipids bearing n-3 fatty acids (most in PC and PE) was also recorded. These lipids have potential applications in food, feed and pharmaceutical industries, contributing to the valorization of halophytes produced under sustainable aquaculture practices.publishe

Estimating lengths-of-stay of hospitalised COVID-19 patients using a non-parametric model: a case study in Galicia (Spain)

Estimating the lengths-of-stay (LoS) of hospitalised COVID-19 patients is key for predicting the hospital beds' demand and planning mitigation strategies, as overwhelming the healthcare systems has critical consequences for disease mortality. However, accurately mapping the time-to-event of hospital outcomes, such as the LoS in the intensive care unit (ICU), requires understanding patient trajectories while adjusting for covariates and observation bias, such as incomplete data. Standard methods, such as the Kaplan-Meier estimator, require prior assumptions that are untenable given current knowledge. Using real-time surveillance data from the first weeks of the COVID-19 epidemic in Galicia (Spain), we aimed to model the time-to-event and event probabilities of patients' hospitalised, without parametric priors and adjusting for individual covariates. We applied a non-parametric mixture cure model and compared its performance in estimating hospital ward (HW)/ICU LoS to the performances of commonly used methods to estimate survival. We showed that the proposed model outperformed standard approaches, providing more accurate ICU and HW LoS estimates. Finally, we applied our model estimates to simulate COVID-19 hospital demand using a Monte Carlo algorithm. We provided evidence that adjusting for sex, generally overlooked in prediction models, together with age is key for accurately forecasting HW and ICU occupancy, as well as discharge or death outcomes.Comment: 14 pages, 4 figure

UV inscription and pressure induced long-period gratings through 3D printed amplitude masks

In this work, we demonstrate for the first time the capability to inscribe long-period gratings (LPGs) with UV radiation using simple and low cost amplitude masks fabricated with a consumer grade 3D printer. The spectrum obtained for a grating with 690 µm period and 38 mm length presented good quality, showing sharp resonances (i.e., 3 dB bandwidth < 3 nm), low out-of-band loss (~0.2 dB), and dip losses up to 18 dB. Furthermore, the capability to select the resonance wavelength has been demonstrated using different amplitude mask periods. The customization of the masks makes it possible to fabricate gratings with complex structures. Additionally, the simplicity in 3D printing an amplitude mask solves the problem of the lack of amplitude masks on the market and avoids the use of high resolution motorized stages, as is the case of the point-by-point technique. Finally, the 3D printed masks were also used to induce LPGs using the mechanical pressing method. Due to the better resolution of these masks compared to ones described on the state of the art, we were able to induce gratings with higher quality, such as low out-of-band loss (0.6 dB), reduced spectral ripples, and narrow bandwidths (~3 nm).publishe