Oscillatory mixed difference systems

The aim of this paper is to discuss the oscillatory behavior of difference systems of mixed type. Several criteria for oscillations are obtained. Particular results are included in regard to scalar equations. Copyright © 2006 J. M. Ferreira and S. Pinelas. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, dis-tribution, and reproduction in any medium, provided the original work is properly cited. 1

Nonoscillations in retarded systems

AbstractThis note is concerned with the existence of nonoscillatory solutions of a linear retarded system. Several criteria for nonoscillations are obtained, some of them regarding specific classes of continuous and differentiable delay functions

Oscillatory Difference Equations and Moment Problems

Abstract In this paper, we first consider some new oscillatory results with respect to the discrete Hermite polynomials of type I, respectively, type II and the Heim-Lorek polynomials. In the second part, we investigate the oscillatory and boundedness properties of the related orthogonality measures and the functions representing them. The polynomials considered so far in this article are closely related to the concept of the Wess-Ruffing discretization.</jats:p

Physical vapor deposition technology in personal protective equipment production: improved antibacterial and hydrophobic character of textiles

Personal protective equipment (PPE) has been adapted as biological threats have emerged, such as increasingly drug-resistant bacteria and the emergence of new viruses such as COVID-19. PPE must be increasingly resilient to prevent the proliferation of pathogens, but using sustainable raw materials and environmentally friendly technologies. The aim of this study is to show a new way of modifying the surface of various types of fabrics to enable their efficient use as PPE. The Ag/DLC coating was successfully deposited by sputtering onto several types of textiles using different chemical compositions of Ag/DLC (0, 8, 10, and 12Ag). As a crucial parameter, wettability was evaluated, showing that silver addition increases the hydrophobicity character of the coated fabrics, namely in cotton, changing from hydrophilic to hydrophobic. Antibacterial activity and cytotoxicity were evaluated on all coatings, revealing that they are efficient in eliminating the spread of bacteria (Staphylococcus aureus and Klebsiella pneumoniae) and pose no risk to the human body. The results presented here are promising in protecting healthcare workers, with the next steps being to study the efficiency of these coatings against viruses. In addition, this study reveals an opportunity to use sustainable fabrics, such as cotton, with high efficiency in protection against pathogens, instead of synthetic fiber textiles.info:eu-repo/semantics/publishedVersio

Analytical and numerical treatment of oscillatory mixed differential equations with differentiable delays and advances

NOTICE: this is the author’s version of a work that was accepted for publication in Journal of computational and applied mathematics. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of computational and applied mathematics, 235(2011), doi: 10.1016/j.cam.2011.04.041This article discusses the oscillatory behaviour of the differential equation of mixed type

Olive yield and physicochemical properties of olives and oil in response to nutrient application under rainfed conditions

The effects of mineral fertilizers on the physicochemical properties of olives and oil under rainfed conditions is scarce. In this three-year study, the results of a nitrogen (N), phosphorus (P), potassium (K) and boron (B) fertilization trial carried out in a young rainfed olive grove and arranged as a nutrient omission trial are reported. The control consisted of the application of N, P, K and B (NPKB) and four other treatments corresponded to the removal of one of them (N0, P0, K0 and B0). Olive yield and several variables associated with the physicochemical properties of olives and oil were evaluated. The NPKB treatment increased olive yield compared to the treatment that did not receive N (N0). Although dependent on the climate conditions of the crop season, the NPKB treatment increased fruit weight and the pulp/pit ratio and its fruits tended to accumulate more oil than K0. However, the phenolics concentrations on fruits and oil tended to be lower. All olive oil samples were classified in the “extra virgin” category and all showed a decrease in its stability between 3 and 15 months of storage, regardless of treatment, especially in N0, P0 and B0 treatments. The results of the sensorial analysis indicate that all the oils fell into the medium fruitiness and greenly-fruity category. Only in P0 and B0 were defects detected, namely muddy sediment. Thus, this study seems to indicate the importance of N application, but also a balanced nutrient application and that further studies are needed, given the difficulty in finding clear trends in the response of measured variables to fertilizer treatments.Ermelinda Silva acknowledges the financial support provided by national funds through FCT -Portuguese Foundation for Science and Technology (PD/BD/128274/2017), under the Doctoral Programme “Agricultural Production Chains—from fork to farm” (PD/00122/2012) and from the European Social Funds and the Regional Operational Programme Norte 2020. This research was funded by the Operational Group “Novas práticas em olivais de sequeiro: estratégias de mitigação e adaptação às alterações climáticas”, funded by PT2020 and EAFRD (European Agricultural Fund for Rural Development). The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UIDB/00690/2020) and CITAB (UIDB/04033/2020) and also to AgriFood XXI Project, No. NORTE-01-0145-FEDER- 000041, co-financed by the European Regional Development Fund (ERDF) through NORTE 2020 (North Regional Operational Program 2014–2020). Ermelinda Silva also acknowledges the present financial support throughout project NORTE-06-3559-FSE-000103 funded by the Fundo Social Europeu (FSE) and FCT research unit Centre BIO R&D Unit (UIDB/05083/2020).info:eu-repo/semantics/publishedVersio