2,833 research outputs found
Dynamics of the birational maps arising from and quivers
The dynamics of the maps associated to and quivers is studied in
detail. We show that the corresponding reduced symplectic maps are conjugate to
globally periodic maps by providing explicit conjugations. The dynamics in
\Rb^N_+ of the original maps is obtained by lifting the dynamics of these
globally periodic maps and the solution of the discrete dynamical systems
generated by each map is given. A better understanding of the dynamics is
achieved by considering first integrals. The relationship between the complete
integrability of the globally periodic maps and the dynamics of the original
maps is explored
Economic burden of personal protective strategies for dengue disease: an optimal control approach
Dengue fever is a vector-borne disease that is widely spread. It has a vast impact on the economy of countries, especially where the disease is endemic. The associated costs with the disease comprise prevention and treatment. This study focus on the impact of adopting individual behaviors to reduce mosquito bites - avoiding the disease’s transmission - and their associated costs. An epidemiological model is presented with human and mosquito compartments, modeling the interaction of dengue disease. The model assumed some self-protection measures, namely the use of repellent in human skin, wear treated clothes with repellent, and sleep with treated bed nets. The household costs for these protections are taking into account to study their use. We conclude that personal protection could have an impact on the reduction of the infected individuals and the outbreak duration. The costs associated with the personal protection could represent a burden to the household budget, and its purchase could influence the shape of the infected’s curve.publishe
results from a nationwide population-based study
Funding Information: This study is funded by national funds through FCT - Fundação para a Ciência e Tecnologia, I. P. under the PhD grant SFRH/BD/148420/2019 awarded to the first author. This protocol was included in the PhD previously approved project. EpiReumpaPt was supported by unrestricted grants from Direcção-Geral da Saúde, Fundação Calouste Gulbenkian, Fundação Champalimaud, Fundação AstraZeneca, AbbVie, Merck, Sharp & Dohme, Pfizer, Roche, Servier, Bial, D3A Medical Systems, Happybrands, Center de Medicina Laboratorial Germano de Sousa, Clínica Médica da Praia da Vitória, CAL-Clínica, Galp Energia, Açoreana Seguros, and individual rheumatologists.Background: Worldwide, the current management of knee osteoarthritis appears heterogeneous, high-cost and often not based on current best evidence. The absence of epidemiological data regarding the utilisation of healthcare services may conceal the need for improvements in the management of osteoarthritis. The aim of this study is to explore the profiles of healthcare services utilisation by people with knee osteoarthritis, and to analyse their determinants, according to Andersen’s behavioural model. Methods: We analysed a sample of 978 participants diagnosed with knee osteoarthritis from the population-based study EpiReumaPt, in Portugal. Data was collected with a structured interview, and the diagnosis of knee osteoarthritis was validated by a rheumatologist team. With the Two-step Cluster procedure, we primarily identified different profiles of healthcare utilisation according to the services most used by patients with knee osteoarthritis. Secondly, we analysed the determinants of each profile, using multinomial logistic regression, according to the predisposing characteristics, enabling factors and need variables. Results: In our sample, a high proportion of participants are overweight or obese (82,6%, n = 748) and physically inactive (20,6%, n = 201) and a small proportion had physiotherapy management (14,4%, n = 141). We identified three profiles of healthcare utilisation: “HighUsers”; “GPUsers”; “LowUsers”. “HighUsers” represents more than 35% of the sample, and are also the participants with higher utilisation of medical appointments. “GPUsers” represent the participants with higher utilisation of general practitioner appointments. Within these profiles, age and geographic location – indicated as predisposing characteristics; employment status and healthcare insurance - as enabling factors; number of comorbidities, physical function, health-related quality of life, anxiety and physical exercise - as need variables, showed associations (p < 0,05) with the higher utilisation of healthcare services profiles. Conclusions: Healthcare utilisation by people with knee osteoarthritis is not driven only by clinical needs. The predisposing characteristics and enabling factors associated with healthcare utilisation reveal inequities in the access to healthcare and variability in the management of people with knee osteoarthritis. Research and implementation of whole-system strategies to improve equity in the access and quality of care are paramount in order to diminish the impact of osteoarthritis at individual-, societal- and economic-level.publishersversionpublishe
Theory vs practice: synthesis of red lead following ancient recipes
The synthesis of red lead pigment (chemically lead oxide, Pb3O4) was carried out considering different starting lead compounds. The experimental procedure followed was established according to some recipes of ancient painting treatises and the knowledge of the phase transformation of lead oxides. The samples transformation was monitored by X-ray powder diffraction and selected samples were also characterized by scanning electron microscopy. The pure Pb3O4 phase was obtained for the transformation of PbO2 and 2PbCO3·Pb(OH)2. Morphological studies revealed that the material obtained from PbO2 presented the more homogeneous grain size distribution. The transformation of white lead Kremer Pigment resulted in a mixture of Pbr3O4 (major phase) and cerussite (PbCO3), leading to a sample with low crystallinity.info:eu-repo/semantics/publishedVersio
A Cross-Sectional Population-Based Study
Funding Information: We thank the EpiDoc Unit and EpiReumaPt team for conceptualising, planning, and implementing the main research project. We would like to acknowledge that the present publication was supported by Fundação Ciência e Tecnologia, IP national support through CHRC (UIDP/04923/2020). Funding Information: This work was supported by an independent research grant from Pfizer. DC received national funding through FCT—Fundação para a Ciência e Tecnologia, I. P. under the Ph.D. grant SFRH/BD/148420/2019Background: Hip/knee osteoarthritis (HKOA) is a leading cause of disability and imposes a major socioeconomic burden. The aim of this study is to estimate the prevalence of HKOA in Portugal, characterised the clinical severity of HKOA in the population, and identified sociodemographic, lifestyle, and clinical factors associated with higher clinical and radiographic severity. Methods: Participants with a diagnosis of HKOA from the EpiReumaPt study (2011–2013) were included (n = 1,087). Hip/knee osteoarthritis diagnosis was made through a structured evaluation by rheumatologists according to American College of Rheumatology criteria. Clinical severity was classified based on Hip Disability and Osteoarthritis Outcome Scale (HOOS) and Knee Injury and Osteoarthritis Outcome Scale (KOOS) score tertiles. Radiographic severity was classified based on the Kellgren-Lawrence grades as mild, moderate, or severe. Sociodemographic lifestyle and clinical variables, including the presence of anxiety and depression symptoms, were analysed. Factors associated with higher clinical and radiographic severity were identified using ordinal logistic regression models. Results: Hip/knee osteoarthritis diagnosis was present in 14.1% of the Portuguese population [12.4% with knee osteoarthritis (OA) and 2.9% with hip OA]. Clinical severity was similar between people with hip (HOOS = 55.79 ± 20.88) and knee (KOOS = 55.33 ± 20.641) OA. People in the high HOOS/KOOS tertile tended to be older (64.39 ± 0.70 years), female (75.2%), overweight (39.0%) or obese (45.9%), and had multimorbidity (86.1%). Factors significantly associated with higher clinical severity tertile were age [55–64 years: odds ratio (OR) = 3.18; 65–74 years: OR = 3.25; ≥75 years: OR = 4.24], female sex (OR = 1.60), multimorbidity (OR = 1.75), being overweight (OR = 2.01) or obese (OR = 2.82), and having anxiety symptoms (OR = 1.83). Years of education was inversely associated with higher clinical severity. Factors significantly associated with higher radiographic severity were age (65–74 years: OR = 3.59; ≥75 years: OR = 3.05) and being in the high HOOS/KOOS tertile (OR = 4.91). Being a female and live in Lisbon or in the Centre region were inversely associated with the higher radiographic severity. Conclusion: Hip/knee osteoarthritis is present in ~1.1 million of Portuguese people. Age, educational level, and obesity are independently associated with HKOA clinical severity, whereas age, sex, geographic location, and clinical severity are independently associated with radiographic severity.publishersversionpublishe
Formação reflexiva de professores de Ciências : estudo de casos em suporte multimédia
As estratégias e os dispositivos de formação reflexiva, vantajosamente associados às tecnologias de informação e comunicação (TIC), constituem um potencial a explorar ao nível da formação de professores, na perspectiva de uma melhoria da qualidade do ensino.
É neste âmbito que se enquadra o Projecto Europeu TICEC (As Tecnologias de Informação e de Comunicação e o Estudo de Casos na formação de formadores), procurando desenvolver contributos para a formação reflexiva de professores combinando as TIC e o estudo de casos. A conjugação destes dois recursos permite a análise aprofundada e multidimensional de situações reais de aulas.
O objectivo geral deste projecto consistiu na implementação de metodologias baseadas em estudos de casos, para a formação de professores (inicial e contínua), usando as TIC. Para a sua concretização, foi também objectivo do projecto a criação de materiais multimédia (em formato CD-Rom), usando gravações vídeo de aulas reais. Nesta comunicação apresentamos um dos produtos multimédia construídos, cujo tema - Perguntas dos alunos - assume particular importância na formação didáctica de professores de ciências.Projecto 106483-CP-1-Comenius-CP21, financiado com o apoio da Comissão Europeia.Peer reviewe
Canine hair follicular tumours: a retrospective study
Hair follicular tumours in dog comprise a large and heterogeneous group of neoplasms that display morphological features resembling one or several portions of the normal hair follicle which constitute a huge effort for its diagnosis. Histopathological evaluation is required to better characterize the different types of canine hair follicular tumours, in order to better understand its biological behaviour and to collaborate with the daily clinical practice. Thus, a retrospective, cross-sectional descriptive study was carried out with goal of analyse its frequency and characteristics, in order to contribute to a better understanding of this vast group of tumours. As main results the authors verified a higher incidence of follicular tumours in male dogs, being the most frequent types diagnosed trichoepithelioma, followed by, trichoblastoma, infundibular keratinizing acanthoma and pilomatricoma and the average age of dogs was 8.76 years. Also, malignant tumours represented 31.6% of all canine hair follicular tumours diagnosed (n= 114).info:eu-repo/semantics/publishedVersio
Observing short-range orientational order in small-molecule liquids
AG and TA acknowledge the funding from Slovenian Research Agency, Basic core funding grant P1-0125.
SNF, MGH acknowledge the FCT—Portuguese Foundation for Science and Technology projects PIDDAC (POCI-01-0145-FEDER-007688, Reference UIDB/50025/2020-2023).
Publisher Copyright:
© 2022, The Author(s).Local molecular ordering in liquids has attracted a lot of interest from researchers investigating crystallization, but is still poorly understood on the molecular scale. Classical nucleation theory (CNT), a macroscopic thermodynamic description of condensation, has shortcomings when dealing with clusters consisting of tens of molecules. Cluster formation and local order fluctuations in liquid media are difficult to study due to the limited spatial resolution of electron- and photon-imaging methods. We used NMR relaxometry to demonstrate the existence of dynamic clusters with short-range orientational order in nominally isotropic liquids consisting of elongated molecules. We observed clusters in liquids where the local ordering is driven by polar, steric, and hydrogen-bond interactions between the molecules. In the case of a liquid crystal, measuring the local orientational order fluctuations allowed us to observe the size of these clusters diverging when approaching the phase transition from the isotropic to the nematic phase. These fluctuations are described in terms of rotational elasticity as a consequence of the correlated reorientations of the neighbouring molecules. Our quantitative observations of the dynamic clusters in liquids, numbering about ten or fewer molecules, indicate that this is a general phenomenon in various types of liquids.publishersversionpublishe
a scoping review protocol
Funding Information: This project is funded by National funds through FCT-Fundacao para a Ciencia e Tecnologia, I. P. under the PhD grant SFRH/BD/148420/2019 awarded to the first author. This protocol was included in the PhD previously approved project. Funding Information: Funding This project is funded by national funds through FCT-Fundação para a Ciência e Tecnologia, I. P. under the PhD grant SFRH/BD/148420/2019 awarded to the first author. This protocol was included in the PhD previously approved project. Publisher Copyright: © Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.Introduction Knee osteoarthritis (OA) is a prevalent condition with associated high disability and healthcare costs. Evidence of major gaps in the implementation of evidence-based interventions in people with knee OA led several healthcare systems to implement models of care (MoCs) in order to improve knowledge translation and guaranty their economic sustainability. Nevertheless, there are few studies that analyse the existing body of evidence of MoCs for patients with knee OA in primary healthcare settings. Therefore, we aim to identify MoCs developed for patients with knee OA implemented in primary healthcare and, analyse their core components and outcomes. This scoping review will create knowledge about the components and outcomes of these MoCs which, in the future, will facilitate their transferability to practice. Methods and analysis We will include studies that developed and implemented an MoC for people with knee OA in primary healthcare. We will use the PCC mnemonic, being 'Population' -people with Knee OA, 'Concept' -the MoCs and 'Context' -the primary healthcare setting. We will conduct the search on PubMed, EMBASE, Cochrane Central Register of Controlled Trials, Scopus, Web of Science Core Collection, as well as grey literature databases and relevant institutions and organisations websites, for articles published after 2000. Two independent reviewers will screen titles and abstracts followed by a full-text review to assess papers regarding their eligibility. We will evaluate the methodological quality of the included studies with the Mixed Methods Appraisal tool and apply a data abstraction form to describe and interpret the evidence. Ethics and dissemination As a secondary analysis, this scoping review does not require ethical approval. Findings will be published in peer-review journal, presented in scientific conferences and as a summary through primary healthcare units.publishersversionpublishe
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