A Lotka-Volterra type model analyzed through different techniques

We consider a modified Lotka-Volterra model applied to the predator-prey system that can also be applied to other areas, for instance the bank system. We show that the model is well-posed (non-negativity of solutions and conservation law) and study the local stability using different methods. Firstly we consider the continuous model, after which the numerical schemes of Euler and Mickens are investigated. Finally, the model is described using Caputo fractional derivatives. For the fractional model, besides well-posedness and local stability, we prove the existence and uniqueness of solution. Throughout the work we compare the results graphically and present our conclusions. To represent graphically the solutions of the fractional model we use the modified trapezoidal method that involves the modified Euler method.Comment: Accepted on June 22, 2023 for publicatio

A bounded model checker for SPARK programs

This paper discusses the design and implementation of a bounded model checker for SPARK code, and provides a proof of concept of the utility and practicality of bounded verification for SPARK.This work is funded by ERDF - European Regional Development Fund through the COMPETE Programme (operational programme for competitiveness) and by National Funds through the FCT - Fundacão para a Ciência e a Tecnologia (Portuguese Foundation for Science and Technology) within project FCOMP-01-0124-FEDER-020486

A generalized program verification workflow based on loop elimination and SA form

This paper presents a minimal model of the functioning of program verification and property checking tools based on (i) the encoding of loops as non-iterating programs, either conservatively, making use of invariants and assume/assert commands, or in a bounded way; and (ii) the use of an intermediate single-assignment (SA) form. The model captures the basic workflow of tools like Boogie, Why3, or CBMC, building on a clear distinction between operational and axiomatic semantics. This allows us to consider separately the soundness of program annotation, loop encoding, translation into SA form, and VC generation, as well as appropriate notions of completeness for each of these processes. To the best of our knowledge, this is the first formalization of a bounded model checking of software technique, including soundness and completeness proofs using Hoare logic; we also give the first completeness proof of a deductive verification technique based on a conservative encoding of invariant-annotated loops with assume/assert in SA form, as well as the first soundness proof based on a program logic.This work is partially financed by the ERDF – European RegionalDevelopment Fund through the Operational Programme for Com-petitiveness and Internationalisation - COMPETE 2020 Programmewithin project ‘POCI-01-0145-FEDER-006961’, and by NationalFunds through the Portuguese funding agency, FCT - Fundação para aCiência e a Tecnologia as part of project ‘UID/EEA/50014/2013’. The first author is also sponsored by FCT grant SFRH/BD/52236/2013

Marketing mix and new product diffusion models

In this paper we analyze the relationship between the marketing mix and new product diffusion models. The goal is to obtain a general new product diffusion model that incorporates the classic 4Ps model of the Marketing Mix: Product, Price, Place, Promotion. An empirical study was conducted using mobile broadband adoption data in Japan.info:eu-repo/semantics/publishedVersio

Animal facility videoendoscopic intubation station: tips and tricks from mice to rabbits

Endotracheal intubation of laboratory animals is a common procedure shared by several research fields for different purposes, such as mechanical ventilation of anaesthetized animals, instillation of cytotoxic nanoparticles, infectious agents or tumour cells for induction of disease models, and even for diagnostic and therapeutic purposes. These different research purposes, achieved in different animal models, require technical expertise and equipment that suits every research need from animal facilities. In this short report we propose a videoendoscopic intubation station that could be shared among the most common laboratory animals, namely the mouse, rat, guinea pig and rabbit, from neonates to adult animals. This report aims to contribute to the reduction of animals excluded from experiments due to false paths during direct and blind intubations and to the refinement of procedures by replacing surgical approaches such as tracheotomy.Project ON.2 SR&TD Integrated Program (NORTE-07-0124-FEDER-000017), co- funded by the North Portugal Regional Operational Program (ON.2-O Novo Norte), under the National Strategic Reference Framework, through the European Regional Development Fund (ERDF). This work was also supported by FEDER funds through the Operational Programme Competitiveness Factors – COMPETE and National Funds through FCT – Foundation for Science and Technology under the project POCI-01-0145-FEDER-007038. A Miranda was supported by an FCT grant (SFRH/BD/52059/2012)info:eu-repo/semantics/publishedVersio

Body composition comparison between gender in institutionalized elderly

Este estudo teve como objetivo averiguar sobre a existência de diferenças entre sexos, da composição corporal de idosos institucionalizados.The purpose of this Study was to compare the body composition differences between gender in institutionalized elderly.info:eu-repo/semantics/publishedVersio

Iron-enriched diet contributes to early onset of osteoporotic phenotype in a mouse model of hereditary hemochromatosis

Osteoporosis is associated with chronic iron overload secondary to hereditary hemochromatosis (HH), but the causative mechanisms are incompletely understood. The main objective of this study was to investigate the role of dietary iron on osteoporosis, using as biological model the Hfe-KO mice, which have a systemic iron overload. We showed that these mice show an increased susceptibility for developing a bone loss phenotype compared to WT mice, which can be exacerbated by an iron rich diet. The dietary iron overload caused an increase in inflammation and iron incorporation within the trabecular bone in both WT and Hfe-KO mice. However, the osteoporotic phenotype was only evident in Hfe-KO mice fed the iron-enriched diet. This appeared to result from an imbalance between bone formation and bone resorption driven by iron toxicity associated to Hfe-KO and confirmed by a decrease in bone microarchitecture parameters (identified by micro-CT) and osteoblast number. These findings were supported by the observed downregulation of bone metabolism markers and upregulation of ferritin heavy polypeptide 1 (Fth1) and transferrin receptor-1 (Tfrc), which are associated with iron toxicity and bone loss phenotype. In WT mice the iron rich diet was not enough to promote a bone loss phenotype, essentially due to the concomitant depression of bone resorption observed in those animals. In conclusion the dietary challenge influences the development of osteoporosis in the HH mice model thus suggesting that the iron content in the diet may influence the osteoporotic phenotype in systemic iron overload conditions.National Funds through Foundation for Science and Technology (FCT) Norte-01-0145-FEDER-000012 Portuguese Foundation for Science and Technology (FCT) SFRH/BD/77056/2011 European Regional Development Fund (FEDER) Norte-01-0145-FEDER-000012info:eu-repo/semantics/publishedVersio

Do the strength levels predict the motor coordination in young basketball players?

O objetivo deste estudo foi averiguar sobre a existência de relação entre os níveis de força e a coordenação motora em basquetebolistas pertencentes ao escalão de sub-18.The aim of this study was to analyse the relation between the strength levels and motor coordination in young basketball players.info:eu-repo/semantics/publishedVersio