31 research outputs found

    The time evolution of Md/M˙M_{\mathrm{d}}/\dot M in protoplanetary discs as a way to disentangle between viscosity and MHD winds

    Full text link
    As the classic viscous paradigm for protoplanetary disk accretion is challenged by the observational evidence of low turbulence, the alternative scenario of MHD disk winds is being explored as potentially able to reproduce the same observed features traditionally explained with viscosity. Although the two models lead to different disk properties, none of them has been ruled out by observations - mainly due to instrumental limitations. In this work, we present a viable method to distinguish between the viscous and MHD framework based on the different evolution of the distribution in the disk mass (MdM_{\mathrm{d}}) - accretion rate (M˙\dot M) plane of a disk population. With a synergy of analytical calculations and 1D numerical simulations, performed with the population synthesis code \texttt{Diskpop}, we find that both mechanisms predict the spread of the observed ratio Md/M˙M_{\mathrm{d}}/\dot M in a disk population to decrease over time; however, this effect is much less pronounced in MHD-dominated populations as compared to purely viscous populations. Furthermore, we demonstrate that this difference is detectable with the current observational facilities: we show that convolving the intrinsic spread with the observational uncertainties does not affect our result, as the observed spread in the MHD case remains significantly larger than in the viscous scenario. While the most recent data available show a better agreement with the wind model, ongoing and future efforts to obtain direct gas mass measurements with ALMA and ngVLA will cause a reassessment of this comparison in the near future.Comment: 11 pages, 6 figures, 1 table. Published in ApJ

    Spatial data infrastructures in Malta : state of play 2006

    Get PDF
    Based on limited information, we have found that in Malta, production, management and dissemination of (rather large scale) spatial reference and core thematic data is almost the exclusive responsibility of the Malta Environmental and Planning Authority (MEPA) in general and the subordinate National Mapping Agency (NMA) in particular. Other organizations which are producing spatial information and conducting spatial information system projects include the Land Registry, the National Statistics Office and the Local councils. The private sector seems to play an increasing role in data production, besides systems development and consultancies. Utilities are also increasingly looking at GIS as a means to develop and manage their business.peer-reviewe

    Spatial data infrastructures in Malta : state of play 2010

    Get PDF
    This report aims at summarizing the state of play of SDI in Malta, and at reflecting the degree to which the SDI situation in Malta is similar to the ideas set out in the INSPIRE position papers and the more recent INSPIRE scoping documents. Since documents, project references could hardly be found, the report is based mainly on the study of the few web sites readily accessible in English (some sites with technical specifications or illustrations also in Maltese). The report has been completed by integration and consolidation of comments received early 2003 from representatives of the National Statistics Office and the Malta Environment and Planning Authority (MEPA). Early 2004, more comments were received and taken into account, coming from Malta Environment and Planning Authority and from a private GI-company (Datatrak IT services). The comments were provided in written form (e-mail). The update of 2005 was based on input from Ms. Carol Valentino from MEPA. The update for 2006 was based on various sources, focusing on the legal and organisational elements of the SDI. For the update of 2007, no information regarding data sharing, data sets or services was received. Some information on licence fees could be found through other channels. For the 2009 update, no information regarding the survey questionnaire was received and the main source of information was extracted from the 2009 ICT components for a Shared Environmental Information System State of Play report. In this version obsolete information was removed, while a conclusion paragraph regarding the status of each indicator was added for each component.peer-reviewe

    The additive value of CA19.9 monitoring in a pancreatic cyst surveillance program

    Get PDF
    Background:Surveillance of pancreatic cysts focuses on the detection of (mostly morphologic) features warranting surgery. European guidelines consider elevated CA19.9 as a relative indication for surgery. We aimed to evaluate the role of CA19.9 monitoring for early detection and management in a cyst surveillance population. Methods: The PACYFIC-registry is a prospective collaboration that investigates the yield of pancreatic cyst surveillance performed at the discretion of the treating physician. We included participants for whom at least one serum CA19.9 value was determined by a minimum follow-up of 12 months.Results: Of 1865 PACYFIC participants, 685 met the inclusion criteria for this study (mean age 67 years, SD 10; 61% female). During a median follow-up of 25 months (IQR 24, 1966 visits), 29 participants developed high-grade dysplasia (HGD) or pancreatic cancer. At baseline, CA19.9 ranged from 1 to 591 kU/L (median 10 kU/L [IQR 14]), and was elevated (≥37 kU/L) in 64 participants (9%). During 191 of 1966 visits (10%), an elevated CA19.9 was detected, and these visits more often led to an intensified follow-up (42%) than those without an elevated CA19.9 (27%; p &lt; 0.001). An elevated CA19.9 was the sole reason for surgery in five participants with benign disease (10%). The baseline CA19.9 value was (as continuous or dichotomous variable at the 37 kU/L threshold) not independently associated with HGD or pancreatic cancer development, whilst a CA19.9 of ≥ 133 kU/L was (HR 3.8, 95% CI 1.1–13, p = 0.03). Conclusions: In this pancreatic cyst surveillance cohort, CA19.9 monitoring caused substantial harm by shortening surveillance intervals (and performance of unnecessary surgery). The current CA19.9 cutoff was not predictive of HGD and pancreatic cancer, whereas a higher cutoff may decrease false-positive values. The role of CA19.9 monitoring should be critically appraised prior to implementation in surveillance programs and guidelines.</p

    Impact of clinical phenotypes on management and outcomes in European atrial fibrillation patients: a report from the ESC-EHRA EURObservational Research Programme in AF (EORP-AF) General Long-Term Registry

    Get PDF
    Background: Epidemiological studies in atrial fibrillation (AF) illustrate that clinical complexity increase the risk of major adverse outcomes. We aimed to describe European AF patients\u2019 clinical phenotypes and analyse the differential clinical course. Methods: We performed a hierarchical cluster analysis based on Ward\u2019s Method and Squared Euclidean Distance using 22 clinical binary variables, identifying the optimal number of clusters. We investigated differences in clinical management, use of healthcare resources and outcomes in a cohort of European AF patients from a Europe-wide observational registry. Results: A total of 9363 were available for this analysis. We identified three clusters: Cluster 1 (n = 3634; 38.8%) characterized by older patients and prevalent non-cardiac comorbidities; Cluster 2 (n = 2774; 29.6%) characterized by younger patients with low prevalence of comorbidities; Cluster 3 (n = 2955;31.6%) characterized by patients\u2019 prevalent cardiovascular risk factors/comorbidities. Over a mean follow-up of 22.5 months, Cluster 3 had the highest rate of cardiovascular events, all-cause death, and the composite outcome (combining the previous two) compared to Cluster 1 and Cluster 2 (all P &lt;.001). An adjusted Cox regression showed that compared to Cluster 2, Cluster 3 (hazard ratio (HR) 2.87, 95% confidence interval (CI) 2.27\u20133.62; HR 3.42, 95%CI 2.72\u20134.31; HR 2.79, 95%CI 2.32\u20133.35), and Cluster 1 (HR 1.88, 95%CI 1.48\u20132.38; HR 2.50, 95%CI 1.98\u20133.15; HR 2.09, 95%CI 1.74\u20132.51) reported a higher risk for the three outcomes respectively. Conclusions: In European AF patients, three main clusters were identified, differentiated by differential presence of comorbidities. Both non-cardiac and cardiac comorbidities clusters were found to be associated with an increased risk of major adverse outcomes

    Global overview of the management of acute cholecystitis during the COVID-19 pandemic (CHOLECOVID study)

    Get PDF
    Background: This study provides a global overview of the management of patients with acute cholecystitis during the initial phase of the COVID-19 pandemic. Methods: CHOLECOVID is an international, multicentre, observational comparative study of patients admitted to hospital with acute cholecystitis during the COVID-19 pandemic. Data on management were collected for a 2-month study interval coincident with the WHO declaration of the SARS-CoV-2 pandemic and compared with an equivalent pre-pandemic time interval. Mediation analysis examined the influence of SARS-COV-2 infection on 30-day mortality. Results: This study collected data on 9783 patients with acute cholecystitis admitted to 247 hospitals across the world. The pandemic was associated with reduced availability of surgical workforce and operating facilities globally, a significant shift to worse severity of disease, and increased use of conservative management. There was a reduction (both absolute and proportionate) in the number of patients undergoing cholecystectomy from 3095 patients (56.2 per cent) pre-pandemic to 1998 patients (46.2 per cent) during the pandemic but there was no difference in 30-day all-cause mortality after cholecystectomy comparing the pre-pandemic interval with the pandemic (13 patients (0.4 per cent) pre-pandemic to 13 patients (0.6 per cent) pandemic; P = 0.355). In mediation analysis, an admission with acute cholecystitis during the pandemic was associated with a non-significant increased risk of death (OR 1.29, 95 per cent c.i. 0.93 to 1.79, P = 0.121). Conclusion: CHOLECOVID provides a unique overview of the treatment of patients with cholecystitis across the globe during the first months of the SARS-CoV-2 pandemic. The study highlights the need for system resilience in retention of elective surgical activity. Cholecystectomy was associated with a low risk of mortality and deferral of treatment results in an increase in avoidable morbidity that represents the non-COVID cost of this pandemic

    Combination therapy with amantadine and interferon in naive patients with chronic hepatitis C: meta-analysis of individual patient data from six clinical trials

    No full text
    Background/Aims: In chronic hepatitis C, clinical trials evaluating the efficacy of amantadine (AMA) and interferon (INF) compared to INF monotherapy, have produced conflicting results. We performed a meta-analysis of the individual patient's data from previous studies. Methods: Nine hundred and seventy-two patients from six European centres were evaluated by means of individual patient meta-analysis, using mixed models with centres and the centre-treatment interaction fitted as random variables. Results: At the end of therapy, virological responses were 38.5% (95% CI 34.1-42.8) after INF and AMA, and 29.5% (95% CI 25.5-33.6) after INF alone (P = 0.003). Sustained response occurred in 111 (23.1%; 95% CI 19.3-20.2) and 85 patients (17.3%; 95% CI 14.0-20.7), respectively (P = 0.03). Even accounting for the centre effect, therapy with AMA and INF was more effective than IFN alone (P = 0.029). When genotypes and viraemia levels were combined, the response rate after combination therapy doubled that observed with IFN alone in all subgroups, except those with low viraemia and genotypes 2 or 3. Conclusions: In chronic hepatitis C, therapy with AMA and INF is effective and may be an alternative to INF and ribavirin in patients who cannot tolerate ribavirin

    Indications, Detection, Completion and Retention Rates of Capsule Endoscopy in Two Decades of Use : A Systematic Review and Meta-Analysis

    No full text
    Background: Capsule endoscopy (CE) has become a widespread modality for non-invasive evaluation of the gastrointestinal (GI) tract, with several CE models having been developed throughout the years. The aim of this systematic review and meta-analysis is to evaluate performance measures such as completion, detection and retention rates of CE. Methods: Literature through to August 2021 was screened for articles regarding all capsule types: small bowel, double-headed capsule for the colon or PillCam® Crohn’s capsule, magnetically-controlled capsule endoscopy, esophageal capsule and patency capsule. Primary outcomes included detection rate (DR), completion rate (CR) and capsule retention rate (RR). DR, CR and RR were also analyzed in relation to indications such as obscure GI bleeding (OGIB), known/suspected Crohn’s disease (CD), celiac disease (CeD), neoplastic lesions (NL) and clinical symptoms (CS). Results: 328 original articles involving 86,930 patients who underwent CE were included. OGIB was the most common indication (n = 44,750), followed by CS (n = 17,897), CD (n = 11,299), NL (n = 4989) and CeD (n = 947). The most used capsule type was small bowel CE in 236 studies. DR, CR and RR for all indications were 59%, 89.6% and 2%, respectively. According to specific indications: DR were 55%, 66%, 63%, 52% and 62%; CR were 90.6%, 86.5%, 78.2%, 94% and 92.8%; and RR were 2%, 4%, 1%, 6% and 2%. Conclusions: Pooled DR, CR and RR are acceptable for all capsule types. OGIB is the most common indication for CE. Technological advancements have expanded the scope of CE devices in detecting GI pathology with acceptable rates for a complete examination
    corecore