Percorrer por data de Publicação, começado por "2026-01"
A mostrar 1 - 7 de 7
Resultados por página
Opções de ordenação
- How many strides are needed for reliable markerless gait analysis?Publication . Carvalho, Andreia; Vanrenterghem, Jos; Pataky, Todd C.; Robinson, Mark A.; Veloso, António P.; Moniz-Pereira, VeraBackground/aim: Markerless motion capture is an emerging tool for gait analysis. In some populations, e.g., older adults, traditional gait analysis poses practical challenges, such as reduced assessment tolerance, and the number of strides collected can be limited. This study aimed to investigate the influence of the number of strides on test-retest reliability and measurement error of markerless gait biomechanics in older adults. Methods: Twenty strides were extracted from 29 healthy older adults for each of two sessions. Lower-limb kinematics and kinetics were computed. Subsequently, non-consecutive random subsets of k = 2-19 strides were averaged within-subjects and within-sessions, including scenarios with unequal k between sessions. Integrated Intraclass Correlation Coefficients (iICCA,k) and Standard Errors of Measurement (SEM) were calculated for trajectory data. ICCA,k [Confidence Intervals] were computed for the range of motion and peaks. Two arbitrary thresholds for the minimally acceptable number of strides were combined: (1) the smallest k that yielded an ICC within 10 % of the maximum ICC across all k, and (2) an absolute ICC threshold of 0.75. SEM≤ 2º was deemed suitable for kinematics, and SEM%≤ 5 % for kinetics. Results: For joint angles and moments, iICC dropped less than 10 % from the highest iICC when using ≥ 7 strides with an equal number of strides across sessions, attaining iICCs≥ 0.75. Reducing the number of strides in one session had less impact than reducing both equally. Lower Confidence intervals were generally ≥ 0.75 for discrete parameters. Kinematic SEM rarely exceeds 2º. Globally, 4 strides are needed to have a kinetics SEM%≤ 5 %. Conclusion: A minimum of 7 strides contributing to the average observation is generally sufficient to achieve reliable markerless kinematics and kinetics in older adults. These results have particular relevance to populations who may experience limited tolerance for lengthy assessments. Allowing flexibility in stride number collected across sessions, while maintaining reliability, contributes to optimizing data collection strategies.
- Applicability of MRI-only technique in external beam radiotherapy: dosimetric evaluation, IGRT, and quality assurance (a systematic review)Publication . Pereira, Daniel; Pereira, Luís; Barbosa, J.; Caetano, MarcoIntroduction: Magnetic Resonance Imaging (MRI) provides superior soft tissue contrast compared to planning Computed Tomography (pCT). Although pCT remains the standard method in radiotherapy planning due to its provision of electron density information required for dose calculations, the MRI-only technique can replace pCT by generating synthetic CTs (sCTs) that supply the necessary density data. Methods: A systematic literature review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The literature search was performed in April 2025 across the PubMed, Scopus, and Web of Science databases, applying inclusion and exclusion criteria defined using the PICOS model. The included studies were assessed using the "Appraising the Evidence: Reviewing Disparate Data Systematically" tool, and extracted data were synthesised in a narrative summary table. Results: A total of 41 studies were included, covering different anatomical regions. The studies reported non-significant differences in dose-volume histograms (DVH) between sCT and CT. Gamma analysis conformity evaluations showed pass rates >87.4 %. The deviations across various image registrations remained <2 mm for translational displacements and <1.2° for rotations. Discrepancies between sCT-CT and sCT-Cone Beam CT were ≤1 %. Conclusion: The MRI-only technique proved to be feasible for use in the central nervous system and pelvic regions, both in terms of dosimetry and image-guided verification. In head and neck oncology, the focus was exclusively on dosimetric planning. Further studies are required to validate and expand the applicability of this technique to other anatomical sites. Implications for practice: These findings reinforce the applicability and versatility of the MRI-only approach across multiple anatomical regions and therapeutic contexts, highlighting its potential to improve patient comfort and streamline clinical workflows.
- Hand eczema, risk factors and microbial skin contamination in the Norwegian waste sorting industry: a cross-sectional studyPublication . Alfonso, Jose Hernán; Graff, Pål; Viegas, Carla; Lossius, Astrid Haaskjold; Eriksen, ElkeIntroduction: Hand eczema, skin barrier function, and skin microbial contamination among waste workers are underexplored. This study aims to assess: (1) the prevalence and risk factors of hand eczema, (2) the levels of transepidermal water loss (TEWL), and (3) skin microbial contamination in waste sorting workers. Methods: Using the Nordic Occupational Skin Questionnaire-2002, data were collected from 69 waste sorting workers and 25 office personnel. TEWL was measured with a Tewameter (TM 300, Courage+ Khazaka Electronic, Köln). Microbial skin samples were collected from the left dorsal hand with sterile swabs (Copan, Italy) and cultured. Analyses included descriptive statistics and multivariate logistic regression. Results: The hand eczema prevalence was 25% among waste workers and 40% in office personnel. The prevalence of hand eczema was significantly lower among exposed workers compared to controls (p = 0.012). TEWL and fungal concentrations were comparable across groups. Atopic dermatitis (AD) and nicotine use were significant predictors of HE. The prevalence of hand eczema experienced during the past week was significantly associated with elevated bacterial concentrations (p value = 0.05) in both groups. Conclusions: Waste sorting workers had up to 2.4 times higher prevalence of hand eczema compared with the general population, but a lower prevalence than office workers in the same industry. These findings may reflect a potential healthy worker effect. The potential role of bacterial concentrations in the occurrence of hand eczema warrants further investigation.
- Association between waist circumference, diabetes mellitus, hypertension and dyslipidemia in a population in Northern AngolaPublication . Vita, Carmel Helena; Francisco, António Hélder; Morais, Humberto; Pedro, João de Almeida; Brito, Miguel; Gonçalves, MauerObesity, particularly when it is centrally located, is an important risk factor for the development of cardiovascular diseases. This study aimed to assess the relationship between waist circumference and the presence of diabetes mellitus, hypertension, and dyslipidaemia. A community-based cross-sectional study was conducted as a sub-analysis of CardioBengo in the municipality of Dande, Bengo Province, involving 2,244 individuals aged 18– 84 years. The study included a structured questionnaire and the collection of sociodemographic, anthropometric, hemodynamic, and biochemical data. Analyses were carried out using correlation methods, the construction of ROC (Receiver Operating Characteristic) curves, and the determination of optimal cut-off points according to the Youden index. Waist circumference was positively associated with metabolic risk factors, particularly hypertension, in both sexes. It demonstrated moderate sensitivity and specificity (area under the curve (AUC): 0.725 in men and 0.612 in women). Waist circumference also proved to be a moderate predictor of diabetes mellitus (AUC: 0.648 in men and 0.596 in women) and hypercholesterolaemia (AUC: 0.673 in men and 0.612 in women), with cut-off points varying between 71.5 cm and 89 cm depending on gender. For hypertriglyceridaemia, however, the association was weak (AUC: 0.557 and 0.503). Waist circumference can be used as an indicator of the risk of developing metabolic factors, highlighting its usefulness in predicting hypertension in the Angolan population.
- Corporate social responsibility and corporate reputation in SMEs of the construction sectorPublication . Cabrera-Gala, Ramsés; Lopes Miranda, Sandra MarisaSMEs in the construction sector are immersed in an industry that can be volatile and controversial. Therefore, taking care of the perceptions and what is said about them in this sector is increasingly relevant. For this, it is necessary to implement Corporate Social Responsibility (CSR) actions, which is essential. The objective of this research was to determine the CSR strategies that build corporate reputation for the SME's of the construction sector. Also, the case method with a qualitative approach, being the purposive sampling the one used for this research, that is, a non-probabilistic sampling was used and the data collection was given through written interviews to eight respondents belonging to different stakeholders, including managers, employees, suppliers and customers of two SMEs in the construction sector, one of which is located in Mexico and the other in Bulgaria. This chapter determined seven integral CSR Strategies that impact on the Corporate Reputation,. Additionally, future research opportunities are discussed.
- Contra os canhões: o cinema brasileiro na cena lusíada, do cinema novo às estéticas de guerrilhaPublication . Morais Alexandre, Paulo Jorge; Weyl, FranciscoO artigo investiga a influência do Cinema Novo brasileiro, especialmente a obra de Glauber Rocha, nas cinematografias de resistência em Portugal. A problemática central é compreender como práticas cinematográficas insurgentes, articuladas entre Brasil, Portugal e África lusófona, se consolidam como instrumentos de contestação cultural, política e social em contextos pós-coloniais e neoliberais. O objetivo é analisar as interações históricas e estéticas entre essas cinematografias, suas metodologias de baixo orçamento, trabalho comunitário e estratégias criativas para contornar limitações estruturais, produzindo narrativas contra-hegemônicas. A metodologia combina pesquisa histórica, análise fílmica, revisão bibliográfica e observação participante em contextos de produção, ensino e exibição, incluindo o papel da Escola Superior de Teatro e Cinema (ESTC) e do Instituto Politécnico de Lisboa como polos de formação e difusão desse cinema.
- Quantum theory of plasmon-phonon scattering in multisubband systemsPublication . Ribeiro, Sofia; Terças, HugoWe present a first-principles quantum theory of a critical yet unexplored energy-loss pathway in low-dimensional semiconductors: resonant second-order scattering between multisubband (MSB) plasmons mediated by longitudinal optical phonons. Specifically, we demonstrate how a high-energy MSB plasmon decays into a lower-energy plasmon state via phonon emission-a fundamental process governing energy relaxation and decoherence in quantum wells. Through exact diagonalization of the coupled plasmon-phonon system and derivation of an effective Hamiltonian, we identify density-tunable resonance conditions that maximize scattering efficiency. Our numerical simulations for GaInAs quantum wells reveal scattering rates ( similar to 10ns-1) competitive with radiative losses, with carrier density acting as a control knob. These results resolve the interplay of collective electronic and vibrational modes in confined systems, providing design principles to mitigate losses in infrared photodetectors, quantum cascade lasers, and plasmon-based quantum devices.