153 research outputs found

    Scaling of spontaneous rotation with temperature and plasma current in tokamaks

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    Using theoretical arguments, a simple scaling law for the size of the intrinsic rotation observed in tokamaks in the absence of momentum injection is found: the velocity generated in the core of a tokamak must be proportional to the ion temperature difference in the core divided by the plasma current, independent of the size of the device. The constant of proportionality is of the order of 10kms1MAkeV110\,\mathrm{km \cdot s^{-1} \cdot MA \cdot keV^{-1}}. When the intrinsic rotation profile is hollow, i.e. it is counter-current in the core of the tokamak and co-current in the edge, the scaling law presented in this Letter fits the data remarkably well for several tokamaks of vastly different size and heated by different mechanisms.Comment: 5 pages, 3 figure

    The population impact of rheumatic and musculoskeletal diseases in relation to other non-communicable disorders: comparing two estimation approaches

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    The aim of this study was to quantify the population impact of rheumatic and musculoskeletal diseases (RMDs) with other non-communicable diseases (NCDs), using two complementary strategies: standard multivariate models based on global burden of disease (GBD)-defined groups vs. empirical mutually exclusive patterns of NCDs. We used cross-sectional data from the Portuguese Fourth National Health Survey (n = 23,752). Six GBD-defined groups were included: RMDs, chronic obstructive pulmonary disease or asthma, cancer, depression, diabetes or renal failure, and stroke or myocardial infarction. The empirical approach comprised the patterns “low disease probability”, “cardiometabolic conditions”, “respiratory conditions” and “RMDs and depression”. As recommended by the outcome measures in rheumatology (OMERACT) initiative, health outcomes included life impact, pathophysiological manifestations, and resource use indicators. Population attributable fractions (PAF) were computed for each outcome and bootstrap confidence intervals (95% CI) were estimated. Among GBD-defined groups, RMDs had the highest impact across all the adverse health outcomes, from frequent healthcare utilization (PAF 7.8%, 95% CI 6.2–9.3) to negative self-rated health (PAF 18.1%, 95% CI 15.4–20.6). In the empirical approach, patterns “cardiometabolic conditions” and “RMDs and depression” had similar PAF estimates across all adverse health outcomes, but “RMDs and depression” showed significantly higher impact on chronic pain (PAF 8.9%, 95% CI 7.6–10.3) than the remaining multimorbidity patterns. RMDs revealed the greatest population impact across all adverse health outcomes tested, using both approaches. Empirical patterns are particularly interesting to evaluate the impact of RMDs in the context of their co-occurrence with other NCDs.This study received no specific funding. The funding for EPI Unit is obtained from the National Foundation for Science and Technology (FCT UID/DTP/04750/2013/002). FAA is supported by Grant FCT SFRH/BD/85398/2012, TM by Grant FCT SFRH/BD/92370/2013 and RL by Grant FCT SFRH/BPD/88729/2012

    Comparative epidemiological study of breast cancer in humans and canine mammary tumors: insights from Portugal

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    Dogs spontaneously develop mammary gland tumors (MGT) and exhibit striking similarities in clinical and epidemiological characteristics to human breast cancer (HBC). Descriptive and comparative analysis of HBC and canine MGT with a focus on evaluating similarities and geographical distribution were the aims of this study. HBC cases were obtained from North Regional Oncological Registry (RORENO) (2010–2015) and canine MGT cases from Vet-OncoNet (2019–2022). Analyses were performed based on published and well accepted classification systems (ICD-O-3.2 for humans and Vet-ICD-O-canine-1). Age-standardized incidence risks (ASIR) of Porto district municipalities were calculated using 2021 Portuguese census (INE) and data from the Portuguese animal registration system (SIAC). Among 7,674 HBC cases and 1,140 MGT cases, a similar age and sex distribution pattern was observed. Approximately 69.2% of HBC cases were between 40 and 69 years old, while 66.9% of MGT cases were diagnosed between 7 and 12 years old (mean age of 9.6 years, SD = 2.6). In women, Invasive breast carcinoma (8500/3) was the most common histological type (n = 5,679, 74%) while in dogs it was the Complex Carcinoma (8983.1/3) (n = 205, 39%). Cocker and Yorkshire Terriers exhibited the highest relative risks (3.2 and 1.6, p < 0.05, respectively) when compared to cross breed dogs. The municipalities' ASIR of the two species exhibited a high correlation (R = 0.85, p < 0.01) and the spatial cluster analysis revealed similar geographic hotspots. Also, higher ASIR values both in women and dogs were more frequently found in urbanized areas compared to rural areas. This research sheds light on the shared features and geographical correlation between HBC and canine MGT, highlighting the potential of cross-species environmental oncology studies. Copyright © 2023 Carvalho, Niza-Ribeiro, Amorim, Queiroga, Severo, Ribeiro and Pinello.The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This study was financed through the financial support of the School of Medicine and Biomedical Sciences, ICBAS, University of Porto. Ana Isabel Ribeiro was supported by National Funds through FCT, under the Stimulus of Scientific Employment—Individual Support programme within the contract CEECIND/02386/2018

    Sex differences in presenting symptoms of acute coronary syndrome: the EPIHeart cohort study

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    Objectives Prompt diagnosis of acute coronary syndrome (ACS) remains a challenge, with presenting symptoms affecting the diagnosis algorithm and, consequently, management and outcomes. This study aimed to identify sex differences in presenting symptoms of ACS. Design Data were collected within a prospective cohort study (EPIHeart). Setting Patients with confirmed diagnosis of type 1 (primary spontaneous) ACS who were consecutively admitted to the Cardiology Department of two tertiary hospitals in Portugal between August 2013 and December 2014. Participants Presenting symptoms of 873 patients (227 women) were obtained through a face-to-face interview. Outcome measures: Typical pain was defined according to the definition of cardiology societies. Clusters of symptoms other than pain were identified by latent class analysis. Logistic regression was used to quantify differences in presentation of ACS symptoms by sex. Results Chest pain was reported by 82% of patients, with no differences in frequency or location between sexes. Women were more likely to feel pain with an intensity higher than 8/10 and this association was stronger for patients aged under 65 years (interaction P=0.028). Referred pain was also more likely in women, particularly pain referred to typical and atypical locations simultaneously. The multiple symptoms cluster, which was characterised by a high probability of presenting with all symptoms, was almost fourfold more prevalent in women (3.92, 95% CI 2.21 to 6.98). Presentation with this cluster was associated with a higher 30-day mortality rate adjusted for the GRACE V.2.0 risk score (4.9% vs 0.9% for the two other clusters, P<0.001). Conclusions While there are no significant differences in the frequency or location of pain between sexes, women are more likely to feel pain of higher intensity and to present with referred pain and symptoms other than pain. Knowledge of these ACS presentation profiles is important for health policy decisions and clinical practice.This study was funded by FEDER through the Operational Programme Competitiveness and Internationalization and national funding from the Foundation for Science and Technology (FCT; Portuguese Ministry of Science, Technology and Higher Education) (FCOMP-01-0124-FEDER-028709), under the project ’Inequalities in coronary heart disease management and outcomes in Portugal' (Ref. FCT PTDC/DTP-EPI/0434/2012) and Unidade de Investigação em Epidemiologia—Instituto de Saúde Pública da Universidade do Porto (EPIUnit) (POCI-01-0145-FEDER-006862; Ref. UID/DTP/04750/2013)

    Do item-writing flaws reduce examinations psychometric quality?

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    Background The psychometric characteristics of multiple-choice questions (MCQ) changed when taking into account their anatomical sites and the presence of item-writing flaws (IWF). The aim is to understand the impact of the anatomical sites and the presence of IWF in the psychometric qualities of the MCQ. Results 800 Clinical Anatomy MCQ from eight examinations were classified as standard or flawed items and according to one of the eight anatomical sites. An item was classified as flawed if it violated at least one of the principles of item writing. The difficulty and discrimination indices of each item were obtained. 55.8 % of the MCQ were flawed items. The anatomical site of the items explained 6.2 and 3.2 % of the difficulty and discrimination parameters and the IWF explained 2.8 and 0.8 %, respectively. Conclusions The impact of the IWF was heterogeneous, the Writing the Stem and Writing the Choices categories had a negative impact (higher difficulty and lower discrimination) while the other categories did not have any impact. The anatomical site effect was higher than IWF effect in the psychometric characteristics of the examination. When constructing MCQ, the focus should be in the topic/area of the items and only after in the presence of IWF.This work was supported by the IJUP Project under Grant Number PP_IJUP2011 67info:eu-repo/semantics/publishedVersio

    Comparative electron temperature measurements of Thomson scattering and electron cyclotron emission diagnostics in TCABR plasmas

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    We present the first simultaneous measurements of the Thomson scattering and electron cyclotron emission radiometer diagnostics performed at TCABR tokamak with Alfven wave heating. The Thomson scattering diagnostic is an upgraded version of the one previously installed at the ISTTOK tokamak, while the electron cyclotron emission radiometer employs a heterodyne sweeping radiometer. For purely Ohmic discharges, the electron temperature measurements from both diagnostics are in good agreement. Additional Alfven wave heating does not affect the capability of the Thomson scattering diagnostic to measure the instantaneous electron temperature, whereas measurements from the electron cyclotron emission radiometer become underestimates of the actual temperature values. (C) 2010 American Institute of Physics. [doi:10.1063/1.3494379]811

    Impact of montelukast as add on treatment to the novel coronavirus pneumonia (COVID-19): protocol for an investigator-initiated open labeled randomized controlled pragmatic trial

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    Background: Montelukast, a safe drug widely use in asthmatic patients, may be an adjuvant in the treatment of Covid-19, either by improving lung injury and inflammation, or by acting as an anti-viral drug. We aim to assess the efficacy and safety of montelukast as add-on treatment in patients with Covid-19. Methods: We propose a randomized, controlled, parallel, open-label trial involving 160 hospitalized adult patients with confirmed Covid-19. Patients will be randomly assigned in a 1:1 ratio to receive either montelukast 10 mg, once a day for 14 days, in addition to standard of care (SoC), or SoC alone. SoC will follow the best practice for treating these patients, according to updated recommendations. The primary outcome is time to recovery. Participants will be assessed using diary cards to capture data on treatment-related improvements in an 8-point ordinal scale. Secondary endpoints will include changes in respiratory and inflammatory parameters, and adverse events. This phase IV clinical trial will take place at the University Hospital of São João, Porto. EudraCT number: 2020-001747-21. Results: This study intends to generate scientific evidence on efficacy and safety of montelukast as add-on treatment in Covid-19. The results will be essential to improve clinical outcomes which remains to be determined. Conclusion: Montelukast has been suggested as a potential drug with 2 main actions on Covid-19. The validation of montelukast as an adjuvant treatment may improve lung injury, inflammation, and symptoms leading to a better prognosis. The use of this drug may fulfil the existing gap on therapeutic options
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