An approximation of flights, delays and costs for different forecast scenarios: A backcasting exercise.

Air Navigation Service Providers (ANSPs) play a critical role as a natural monopoly within the air traffic system and are subject to regulation. Achieving preset performance targets necessitates efficient resource planning, contingent upon accurate traffic forecasts. This means that forecast precision is a key determinant of operational efficiency. In this study, we employ backcasting techniques to gauge the influence of forecast errors on air traffic management performance. This is done for eleven airspaces and seven years of data. The paper seeks to estimate the cost of delays if the actual number of flights for the period 2015-2020 had been as predicted by EUROCONTROL through its specialised service STATFOR. To assess the impact of forecasting errors, we analyse the discrepancy between the predicted and actual figures for flight data, specifically focusing on delays. Our results show that forecast errors have a noteworthy, adverse effect on performance. Inaccurate predictions prevent efficient resource allocation. We prove that a marginal increase in forecast quality would significantly reduce overall costs for stakeholders.

Vertebral endplate changes are not associated with chronic low back pain among Southern European subjects: a case control study.

BACKGROUND AND PURPOSE: Data on the association between vertebral endplate changes and low back pain are contradictory. This study was designed to assess whether this association exists among Southern European subjects. MATERIALS AND METHODS: Patients in this study serving as cases were 35-50 years of age with low back pain lasting >90 days, for whom a lumbar MR imaging had been prescribed. Controls were subjects 35-50 years of age, having a cranial MR imaging for headache with normal findings, and no history of clinically relevant LBP. Two hundred forty cases and 64 controls were recruited consecutively in the radiology services across 6 cities in Spain. Imaging findings and subject characteristics were gathered through previously validated instruments. Radiologists who interpreted MRI were blinded to the subject characteristics. A multivariate logistic regression model was developed to assess the association of vertebral endplate changes with LBP, adjusting for sex, age, body mass index, lifetime exposure to smoking, physical activity, disk degeneration, and the interaction between disk degeneration and vertebral endplate changes. RESULTS: Vertebral endplate changes were found in 80.4% of the cases and in 87.5% of the controls. In the regression model, disk degeneration was the only variable showing a confounding effect. Results showed that after adjusting for disk degeneration, the presence of vertebral endplate changes is associated with the absence of chronic LBP (OR for LBP: 0.31; 95% CI, 0.10-0.95). CONCLUSIONS: In Southern European subjects, vertebral endplate changes are not associated with chronic LBP.

Influence of nomenclature in the interpretation of lumbar disk contour on MR imaging: a comparison of the agreement using the combined task force and the nordic nomenclatures.

BACKGROUND AND PURPOSE: The CTF nomenclature had not been tested in clinical practice. The purpose of this study was to compare the reliability and diagnostic confidence in the interpretation of disk contours on lumbar 1.5T MR imaging when using the CTF and the Nordic nomenclatures. MATERIALS AND METHODS: Five general radiologists from 3 hospitals blindly and independently assessed intravertebral herniations (Schmorl node) and disk contours on the lumbar MR imaging of 53 patients with low back pain, on 4 occasions. Measures were taken to minimize the risk of recall bias. The Nordic nomenclature was used for the first 2 assessments, and the CTF nomenclature, in the remaining 2. Radiologists had not previously used either of the 2 nomenclatures. κ statistics were calculated separately for reports deriving from each nomenclature and were categorized as almost perfect (0.81-1.00), substantial (0.61-0.80), moderate (0.41-0.60), fair (0.21-0.40), slight (0.00-0.20), and poor (<0.00). RESULTS: Categorization of intra- and interobserver agreement was the same across nomenclatures. Intraobserver reliability was substantial for intravertebral herniations and disk contour abnormalities. Interobserver reliability was moderate for intravertebral herniations and fair to moderate for disk contour. CONCLUSIONS: In conditions close to clinical practice, regardless of the specific nomenclature used, a standardized nomenclature supports only moderate interobserver agreement. The Nordic nomenclature increases self-confidence in an individual observer's report but is less clear regarding the classification of disks as normal versus bulged.

Agreement in the interpretation of magnetic resonance images of the lumbar spine.

BACKGROUND: Correlation between clinical features and magnetic resonance imaging (MRI) findings is essential in low-back-pain patients. Most previous studies have analyzed concordance in the interpretation of lumbar MRI among a few radiologists who worked together. This may have overestimated concordance. PURPOSE: To evaluate intra- and interobserver agreement in the interpretation of lumbar MRI performed in an open 0.2 T system. MATERIAL AND METHODS: Seven radiologists from two different geographic settings in Spain interpreted the lumbar MRIs of 50 subjects representative of the general Danish population aged 40 years. The radiologists interpreted the images in routine clinical practice, having no knowledge of the clinical and demographic characteristics of the subjects and blinded to their colleagues' assessments. Six of the radiologists evaluated the same MRIs 14 days later, having no knowledge of the previous results. Data on the existence of disc degeneration, high-intensity zones, disc contour, Schmorl nodes, Modic changes, osteophytes, spondylolisthesis, and spinal stenosis were collected in the Nordic Modic Consensus Group Classification form. Intra- and interobserver agreement was analyzed for variables with a prevalence >or=10% and