Optimum Bayesian thresholds for rebalanced classification problems using class-switching ensembles

Asymmetric label switching is an effective and principled method for creating a diverse ensemble of learners for imbalanced classification problems. This technique can be combined with other rebalancing mechanisms, such as those based on cost policies or class proportion modifications. In this study, and under the Bayesian theory framework, we specify the optimal decision thresholds for the combination of these mechanisms. In addition, we propose using a gating network to aggregate the learners contributions as an additional mechanism to improve the overall performance of the system.We thank the anonymous reviewers for their valuable suggestions and comments. This work is partially funded by Project PID2021-125652OB-I00 from the Ministerio de Ciencia e Innovación of Spain. Funding for APC: Universidad Carlos III de Madrid (Read & Publish Agreement CRUE-CSIC 2022). In memoriam: Prof. Aníbal R. Figueiras-Vidal (1950-2022)

Association Between Preexisting Versus Newly Identified Atrial Fibrillation and Outcomes of Patients With Acute Pulmonary Embolism

Background Atrial fibrillation (AF) may exist before or occur early in the course of pulmonary embolism (PE). We determined the PE outcomes based on the presence and timing of AF. Methods and Results Using the data from a multicenter PE registry, we identified 3 groups: (1) those with preexisting AF, (2) patients with new AF within 2 days from acute PE (incident AF), and (3) patients without AF. We assessed the 90-day and 1-year risk of mortality and stroke in patients with AF, compared with those without AF (reference group). Among 16 497 patients with PE, 792 had preexisting AF. These patients had increased odds of 90-day all-cause (odds ratio [OR], 2.81; 95% CI, 2.33-3.38) and PE-related mortality (OR, 2.38; 95% CI, 1.37-4.14) and increased 1-year hazard for ischemic stroke (hazard ratio, 5.48; 95% CI, 3.10-9.69) compared with those without AF. After multivariable adjustment, preexisting AF was associated with significantly increased odds of all-cause mortality (OR, 1.91; 95% CI, 1.57-2.32) but not PE-related mortality (OR, 1.50; 95% CI, 0.85-2.66). Among 16 497 patients with PE, 445 developed new incident AF within 2 days of acute PE. Incident AF was associated with increased odds of 90-day all-cause (OR, 2.28; 95% CI, 1.75-2.97) and PE-related (OR, 3.64; 95% CI, 2.01-6.59) mortality but not stroke. Findings were similar in multivariable analyses. Conclusions In patients with acute symptomatic PE, both preexisting AF and incident AF predict adverse clinical outcomes. The type of adverse outcomes may differ depending on the timing of AF onset.info:eu-repo/semantics/publishedVersio

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Towards improving automatic partial correction of students' activities/practices

The evaluation of student learning is usually done through activities and exercises where students apply their acquired knowledge in the resolution of problems close to real life, but delimited by the teacher. In these activities and exercises the teacher can evaluate conceptual knowledge and procedural knowledge. In the application area of this project, it is common that in the programming exercises and activities (practices) both types of knowledge are evaluated, since, on the one hand, the application of algorithms (procedural knowledge) and what programming elements and structures are being used (conceptual knowledge) are evaluated. The teacher has the complex task of evaluating this knowledge by making an individualized correction of each practice. While individualized correction of each practice is usually unbeatable in terms of the quality of the correction, on the other hand, automating the evaluation of procedural knowledge provides certain advantages. Routine parts can be evaluated automatically and thus save valuable time for the teacher's correction of other aspects. One of the advantages of automatic correction is that it is immediately available to the students and allows guiding them in essential aspects. In this teaching innovation project, a new online judge called UnitJudge has been developed. This new judge allows automatically evaluating programming practices in a consistent way even when these are long. In the ability to evaluate long practices, it outperforms other existing judges, such as DomJudge, which are more appropriate for short exercises since they are based on global inputs and outputs without allowing students to know which part of the code is failing. The newly developed judge allows to test the different parts based on unit tests. It is implemented for both C++ and Java practices. The new UnitJudge was used in several groups of the Programming Fundamentals subject. Taking into account the averages of 29 students' responses to the validated USE (Usefulness, Satisfaction and Ease of Use) scale, it was concluded that UnitJudge was easy to learn to use (mean of 5.99 out of 7), useful for the students (mean of 5.62 out of 7), and satisfactory for them (mean of 5.12 out of 7). The results of this teaching innovation project have been presented in two papers at the international conference "The 10th International and the 16th National Conference on e-Learning and e-Teaching" (ICELET 2023), respectively about (1) the presentation of UnitJudge and the experiment with the students of Fundamentals of Programming, and (2) intrusion detection from the viewpoint of cybersecurity in online judges exemplified with UnitJudge.La evaluación del aprendizaje de los estudiantes se suele realizar mediante actividades y ejercicios donde los estudiantes aplican sus conocimientos adquiridos en la resolución de problemas cercanos a la vida real, pero acotados por el profesor. En estas actividades y ejercicios el profesor puede evaluar el conocimiento conceptual y el conocimiento procedimental. En el área de aplicación de este proyecto, es común, que en los ejercicios y actividades de programación (prácticas) se evalúen los dos tipos de conocimiento, pues, por un lado, se evalúa la aplicación de algoritmos (conocimiento procedimental) y qué elementos y estructuras de programación se están utilizando (conocimiento conceptual). El profesor tiene la compleja tarea de evaluar estos conocimientos haciendo una corrección individualizada de cada práctica. Si bien la corrección individualizada de cada práctica es habitualmente inmejorable en cuanto a la calidad de la corrección, por otra parte, automatizar la evaluación del conocimiento procedimental proporciona ciertas ventajas. Las partes rutinarias se pueden realizar automáticamente y así ahorrar ese valioso tiempo para la corrección de otros aspectos por parte del profesor. Una de las ventajas de la corrección automática es que está disponible de manera inmediata para los estudiantes y permite guiar al estudiante en aspectos esenciales. En este proyecto de innovación docente se ha desarrollado un nuevo juez en línea llamado UnitJudge. Este nuevo juez permite evaluar automáticamente prácticas de programación de forma coherente incluso aun cuando estas son largas. En la capacidad de evaluar prácticas largas supera a otros jueces existentes, tales como DomJudge, más apropiados para ejercicios cortos dado que se basan en entradas y salidas globales sin permitir detectar qué parte del código está fallando. El nuevo juez desarrollado permite probar las diferentes partes basándose en pruebas unitarias. Está implementado tanto para prácticas con C++ como para Java. El nuevo juez UnitJudge fue usado en varios grupos de la asignatura Fundamentos de Programación. Teniendo en cuenta las medias de las respuestas de 29 estudiantes a la escala validada USE (Usefulness, Satisfaction and Ease of Use), se concluyó que UnitJudge fue fácil de aprender a usar (media de 5.99 sobre 7), fue útil para los estudiantes (media de 5.62 sobre 7), y les resultó satisfactorio (media de 5.12 sobre 7). Los resultados de este proyecto de innovación docente han sido presentados en dos artículos en el congreso internacional “The 10th International and the 16th National Conference on e-Learning and e-Teaching” (ICELET 2023), respectivamente acerca de (1) la presentación de UnitJudge y del experimento con los estudiantes de Fundamentos de Programación, y (2) la detección de intrusiones desde el punto de vista de la ciberseguridad en jueces en línea ejemplificado con UnitJudge.Depto. de Ingeniería de Software e Inteligencia Artificial (ISIA)Fac. de InformáticaFALSEsubmitte

Determinants of Severity in Acute Pancreatitis : A Nation-wide Multicenter Prospective Cohort Study

OBJECTIVE: The aim of this study was to compare and validate the different classifications of severity in acute pancreatitis (AP) and to investigate which characteristics of the disease are associated with worse outcomes. SUMMARY OF BACKGROUND DATA: AP is a heterogeneous disease, ranging from uneventful cases to patients with considerable morbidity and high mortality rates. Severity classifications based on legitimate determinants of severity are important to correctly describe the course of disease. METHODS: A prospective multicenter cohort study involving patients with AP from 23 hospitals in Spain. The Atlanta Classification (AC), Revised Atlanta Classification (RAC), and Determinant-based Classification (DBC) were compared. Binary logistic multivariate analysis was performed to investigate independent determinants of severity. RESULTS: A total of 1655 patients were included; 70 patients (4.2%) died. RAC and DBC were equally superior to AC for describing the clinical course of AP. Although any kind of organ failure was associated with increased morbidity and mortality, persistent organ failure (POF) was the most significant determinant of severity. All local complications were associated with worse outcomes. Infected pancreatic necrosis correlated with high morbidity, but in the presence of POF, it was not associated to higher mortality when compared with sterile necrotizing pancreatitis. Exacerbation of previous comorbidity was associated with increased morbidity and mortality. CONCLUSION: The RAC and DBC both signify an advance in the description and differentiation of AP patients. Herein, we describe the complications of the disease independently associated to morbidity and mortality. Our findings are valuable not only when designing future studies on AP but also for the improvement of current classifications

Clinical Presentation and Short- and Long-term Outcomes in Patients With Isolated Distal Deep Vein Thrombosis vs Proximal Deep Vein Thrombosis in the RIETE Registry

International audienceImportance: Insufficient data exist about the clinical presentation, short-term, and long-term outcomes of patients with isolated distal deep vein thrombosis (IDDVT), that is, thrombosis in infrapopliteal veins without proximal extension or pulmonary embolism (PE).Objective: To determine the clinical characteristics, short-term, and 1-year outcomes in patients with IDDVT and to compare the outcomes in unadjusted and multivariable adjusted analyses with patients who had proximal DVT.Design, setting, and participants: This was a multicenter, international cohort study in participating sites of the Registro Informatizado Enfermedad Tromboembólica (RIETE) registry conducted from March 1, 2001, through February 28, 2021. Patients included in this study had IDDVT. Patients with proximal DVT were identified for comparison. Patients were excluded if they had a history of asymptomatic DVT, upper-extremity DVT, coexisting PE, or COVID-19 infection.Main outcomes and measures: Primary outcomes were 90-day and 1-year mortality, 1-year major bleeding, and 1-year venous thromboembolism (VTE) deterioration, which was defined as subsequent development of proximal DVT or PE.Results: A total of 33 897 patients were identified with isolated DVT (without concomitant PE); 5938 (17.5%) had IDDVT (mean [SD] age, 61 [17] years; 2975 male patients [50.1%]), and 27 959 (82.5%) had proximal DVT (mean [SD] age, 65 [18] years; 14 315 male patients [51.2%]). Compared with individuals with proximal DVT, those with IDDVT had a lower comorbidity burden but were more likely to have had recent surgery or to have received hormonal therapy. Patients with IDDVT had lower risk of 90-day mortality compared with those with proximal DVT (odds ratio [OR], 0.47; 95% CI, 0.40-0.55). Findings were similar in 1-year unadjusted analyses (hazard ratio [HR], 0.52; 95% CI, 0.46-0.59) and adjusted analyses (HR, 0.72; 95% CI, 0.64-0.82). Patients with IDDVT had a lower 1-year hazard of VTE deterioration (HR, 0.83; 95% CI, 0.69-0.99). In 1-year adjusted analyses of patients without an adverse event within the first 3 months, IDDVT was associated with lower risk of VTE deterioration (adjusted HR, 0.48; 95% CI, 0.24-0.97). By 1-year follow-up, symptoms or signs of postthrombotic syndrome were less common in patients with IDDVT (47.6% vs 60.5%).Conclusions and relevance: Results of this cohort study suggest that patients with IDDVT had a less ominous prognosis compared with patients with proximal DVT. Such differences were likely multifactorial, including the differences in demographics, risk factors, comorbidities, particularly for all-cause mortality, and a potential association of thrombus location with VTE deterioration and postthrombotic syndrome. Randomized clinical trials are needed to assess the optimal long-term management of IDDVT

Effects of pre-operative isolation on postoperative pulmonary complications after elective surgery: an international prospective cohort study an international prospective cohort study

We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care. We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care