46 research outputs found

    Effect of the heating of the intergranular water on the softening of a shear band

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    When a landslide takes place, it is believed that a shear band of loose granular media acts as a lubricant between the descending block of soil and the basis on repose. The mechanism involved is known as softening: the granular skeleton looses its stiffness and the shear stress on the block is lost. In the hypothesis of Habib, the friction between grains heats the pore water, increasing its pressure and reducing the effective stress by the Terzagi criterion. Vardoulakis had constructed models on this hypothesis including thermal diffusion and Darcy’s law, plus a double dependence of the friction angle on the displacement and the velocity of the rolling block. Hereby we present a discrete element simulation of the process on a tilted shear band between two soil blocks: one bottom at rest and one upper at move. Soil blocks are assumed with uniform permeability and thermal conductivity. The shear band is modeled as a set of Voronoi polygons with elastic, frictional and damping forces between them. Pore water acts with hydrostatic pressure on the grains and on the upper and lower blocks, with a thermodynamic response that is reproduced by the Steam Tables provided by the International Association for the Properties of Water and Steam (IAPWS 97 report). At each time step, the forces on all grains are computed and all translational and rotational movements are integrated. Then, the heat is computed as the work done by all dissipative forces, distributing between water and grains according to their thermal capacities and increasing water temperature and pressure. Finally, this water pressure pushes the grains apart, reducing the shear stress on the upper block and speeding up the landslide. By this simulation procedure we obtain temperature increments on 10 C° that are strong enough to produce softening. Although the model is in two dimensions, it provides new insights on the study of catastrophic landslides evolutions

    EAACI position paper on occupational rhinitis

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    The present document is the result of a consensus reached by a panel of experts from European and non-European countries on Occupational Rhinitis (OR), a disease of emerging relevance which has received little attention in comparison to occupational asthma. The document covers the main items of OR including epidemiology, diagnosis, management, socio-economic impact, preventive strategies and medicolegal issues. An operational definition and classification of OR tailored on that of occupational asthma, as well as a diagnostic algorithm based on steps allowing for different levels of diagnostic evidence are proposed. The needs for future research are pointed out. Key messages are issued for each item

    The Human Phenotype Ontology in 2024: phenotypes around the world

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    \ua9 The Author(s) 2023. Published by Oxford University Press on behalf of Nucleic Acids Research. The Human Phenotype Ontology (HPO) is a widely used resource that comprehensively organizes and defines the phenotypic features of human disease, enabling computational inference and supporting genomic and phenotypic analyses through semantic similarity and machine learning algorithms. The HPO has widespread applications in clinical diagnostics and translational research, including genomic diagnostics, gene-disease discovery, and cohort analytics. In recent years, groups around the world have developed translations of the HPO from English to other languages, and the HPO browser has been internationalized, allowing users to view HPO term labels and in many cases synonyms and definitions in ten languages in addition to English. Since our last report, a total of 2239 new HPO terms and 49235 new HPO annotations were developed, many in collaboration with external groups in the fields of psychiatry, arthrogryposis, immunology and cardiology. The Medical Action Ontology (MAxO) is a new effort to model treatments and other measures taken for clinical management. Finally, the HPO consortium is contributing to efforts to integrate the HPO and the GA4GH Phenopacket Schema into electronic health records (EHRs) with the goal of more standardized and computable integration of rare disease data in EHRs

    Difficult tracheal intubation in neonates and infants. NEonate and Children audiT of Anaesthesia pRactice IN Europe (NECTARINE): a prospective European multicentre observational study

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    Background: Neonates and infants are susceptible to hypoxaemia in the perioperative period. The aim of this study was to analyse interventions related to anaesthesia tracheal intubations in this European cohort and identify their clinical consequences. Methods: We performed a secondary analysis of tracheal intubations of the European multicentre observational trial (NEonate and Children audiT of Anaesthesia pRactice IN Europe [NECTARINE]) in neonates and small infants with difficult tracheal intubation. The primary endpoint was the incidence of difficult intubation and the related complications. The secondary endpoints were the risk factors for severe hypoxaemia attributed to difficult airway management, and 30 and 90 day outcomes. Results: Tracheal intubation was planned in 4683 procedures. Difficult tracheal intubation, defined as two failed attempts of direct laryngoscopy, occurred in 266 children (271 procedures) with an incidence (95% confidence interval [CI]) of 5.8% (95% CI, 5.1e6.5). Bradycardia occurred in 8% of the cases with difficult intubation, whereas a significant decrease in oxygen saturation (SpO2<90% for 60 s) was reported in 40%. No associated risk factors could be identified among comorbidities, surgical, or anaesthesia management. Using propensity scoring to adjust for confounders, difficult anaesthesia tracheal intubation did not lead to an increase in 30 and 90 day morbidity or mortality. Conclusions: The results of the present study demonstrate a high incidence of difficult tracheal intubation in children less than 60 weeks post-conceptual age commonly resulting in severe hypoxaemia. Reassuringly, the morbidity and mortality at 30 and 90 days was not increased by the occurrence of a difficult intubation event. Clinical trial registration: NCT02350348

    Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

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    BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700

    Elective Cancer Surgery in COVID-19-Free Surgical Pathways During the SARS-CoV-2 Pandemic: An International, Multicenter, Comparative Cohort Study.

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    PURPOSE: As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19-free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS: This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19-free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS: Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19-free surgical pathways. Patients who underwent surgery within COVID-19-free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19-free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score-matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19-free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION: Within available resources, dedicated COVID-19-free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

    Elective cancer surgery in COVID-19-free surgical pathways during the SARS-CoV-2 pandemic: An international, multicenter, comparative cohort study

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    PURPOSE As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19–free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19–free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19–free surgical pathways. Patients who underwent surgery within COVID-19–free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19–free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score–matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19–free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION Within available resources, dedicated COVID-19–free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

    The Human Phenotype Ontology in 2024: phenotypes around the world.

    Get PDF
    The Human Phenotype Ontology (HPO) is a widely used resource that comprehensively organizes and defines the phenotypic features of human disease, enabling computational inference and supporting genomic and phenotypic analyses through semantic similarity and machine learning algorithms. The HPO has widespread applications in clinical diagnostics and translational research, including genomic diagnostics, gene-disease discovery, and cohort analytics. In recent years, groups around the world have developed translations of the HPO from English to other languages, and the HPO browser has been internationalized, allowing users to view HPO term labels and in many cases synonyms and definitions in ten languages in addition to English. Since our last report, a total of 2239 new HPO terms and 49235 new HPO annotations were developed, many in collaboration with external groups in the fields of psychiatry, arthrogryposis, immunology and cardiology. The Medical Action Ontology (MAxO) is a new effort to model treatments and other measures taken for clinical management. Finally, the HPO consortium is contributing to efforts to integrate the HPO and the GA4GH Phenopacket Schema into electronic health records (EHRs) with the goal of more standardized and computable integration of rare disease data in EHRs

    International Consensus Statement on Rhinology and Allergy: Rhinosinusitis

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    Background: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR‐RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR‐RS‐2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence‐based findings of the document. Methods: ICAR‐RS presents over 180 topics in the forms of evidence‐based reviews with recommendations (EBRRs), evidence‐based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary. Results: ICAR‐RS‐2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence‐based management algorithm is provided. Conclusion: This ICAR‐RS‐2021 executive summary provides a compilation of the evidence‐based recommendations for medical and surgical treatment of the most common forms of RS

    Patterns of care and outcome for patients with glioblastoma diagnosed during 2008-2010 in Spain

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    Seit einigen Jahren unterliegt der Bereich der IngenieurgeodĂ€sie einem starken Wandel, da sich diese Disziplin generell den stetig weiterentwickelnden, anwendungsbezogenen Problemstellungen widmet. Unter diesen Aspekten ist insbesondere die flĂ€chenhafte Erfassung von Objekten und ihrer Geometrien – bis hin zur ganzheitlichen Raumkontinuisierung – in den Fokus der IngenieurgeodĂ€sie geraten. In diesem Kontext ergrĂŒndet diese Dissertation, inwieweit die Konfiguration bei der Approximation von OberflĂ€chen, die rĂ€umlich ungleichmĂ€ĂŸig abgetastet wurden, analysiert und gegebenenfalls auch optimiert werden kann. Die zugrunde liegenden Messungen basieren auf Nivellements und terrestrischen Laserscans. Deren OberflĂ€chenabtastung ist jeweils ungleichmĂ€ĂŸig. Bei Nivellements liegt die Ursache in der Wirtschaftlichkeit und Siedlungsstruktur der Untersuchungsgebiete, beim terrestrischen Laserscanning (TLS) kann dies messtechnisch mit der polaren Abtastung begrĂŒndet werden. In beiden FĂ€llen dienen die Messpunkte hĂ€ufig zur Approximation von OberflĂ€chen, um flĂ€chenkontinuierliche Aussagen treffen zu können. GĂ€ngige Anwendungen sind z.B. die Analyse von Bodenbewegungen beim Nivellement oder die Deformationsanalyse beim TLS. Obwohl bei diesen Anwendungen im Allgemeinen eine ausreichend große Anzahl an Messpunkten zur VerfĂŒgung steht, fĂŒhrt die ungleichmĂ€ĂŸige Punktverteilung dennoch oftmals zu einer ungĂŒnstigen Konfiguration des Ausgleichs. Diese kann in Kombination mit dem oft nur limitiert vorhanden Modellwissen bei der FlĂ€chenmodellierung zu verzerrten ParameterschĂ€tzungen fĂŒhren. Diese Konfiguration gilt es demnach zu analysieren und ggf. auch zu optimieren. Auf Basis dieser methodischen Analysen können schwerpunktmĂ€ĂŸig vier Aspekte herausgestellt werden: 1) Anhand der Redundanzanteile sowie anhand von relativen Redundanzanteilunterschieden kann gezeigt werden, dass die ungleichmĂ€ĂŸige Punktverteilung in Kombination mit limitiertem Modellwissen zu einer suboptimalen Konfiguration bei der Approximation von OberflĂ€chen fĂŒhrt. Die Redundanzanteile vereinen sowohl die geometrische Verteilung der Messpunkte, die Objektgeometrie als auch das stochastische Modell der Beobachtungen zur Beurteilung der ZuverlĂ€ssigkeit und der Konfiguration. 2) Zur Optimierung der Konfiguration bei der Approximation flĂ€chenhafter Nivellements wird ein Algorithmus aufgestellt, der die Messpunktverteilung im Bezug zur KomplexitĂ€t der Bodensenkungen objektiv bewertet. Die existierenden Messpunkte werden hinsichtlich ihrer Wichtigkeit fĂŒr die Approximation – auf Basis der Konfiguration – selektiert. ZusĂ€tzlich ist es in der Netzausgleichung erstmals möglich, die Positionen und die Anzahl zusĂ€tzlich benötigter Messpunkte zu bestimmen. 3) Die Approximationen gescannter OberflĂ€chen sind oft verzerrt und abhĂ€ngig vom Standpunkt. Dies kann anhand einer Konfigurationsanalyse unter Betrachtung der Redundanzanteile quantifiziert und analysiert werden. Ferner kann durch eine PunktausdĂŒnnung – also durch die Herstellung einer gleichmĂ€ĂŸigen Abtastung – eine Minimierung der StandpunktabhĂ€ngigkeit erzeugt werden. Dies zeigt sich auch in Form einer verbesserten Konfiguration. 4) Ein weiterentwickeltes Konzept zur scannerbasierten Deformationsuntersuchung integriert die beschriebenen Aspekte der Konfigurationsanalyse und -optimierung anhand eines konkreten Beispiels. Ferner wird der Aspekt der Scannerkalibrierung hervorgehoben und in die Deformationsanalyse integriert. Insgesamt bedeuten diese Maßnahmen einen großen Fortschritt fĂŒr die Nutzung terrestrischer Laserscanner zur zuverlĂ€ssigen und genauen Deformationsanalyse. Diese Ergebnisse sind unmittelbar relevant fĂŒr alle flĂ€chenhaften Approximationen mit hohen Genauigkeitsanforderungen. Im Gesamten stellt diese Dissertation also eine Grundlage zur verbesserten Analyse, Bewertung und Interpretation von Approximationen auf Basis ungleichmĂ€ĂŸig abgetasteter OberflĂ€chen dar. Eingebettet in ebenfalls erwĂ€hnte, weiterfĂŒhrende methodische Untersuchungen ist diese Dissertation damit bei der fĂŒr die IngenieurgeodĂ€sie angestrebten ganzheitlichen Raumkontinuisierung von großem NutzenAnalysis of the configuration at approximating irregularly sampled surfaces based on levellings and terrestrial laser scans Since several years, the field of engineering geodesy has been subject to change. This is due to the fact that engineering geodesy generally attends to applied problem statements. Based on these aspects, especially the area-based acquisition of objects and their geometries – up to an integrated space continualization – got into focus of engineering geodesy. In this context, this dissertation fathoms the possibility of analyzing and optimizing the configuration at approximation surfaces that are spatially irregularly sampled. The underlying measurements are based on levellings and terrestrial laser scans, which both sample the surface irregularly. With levellings, the reason for the irregular sampling is caused by cost effectiveness and the settlement structure of the investigated areas. With terrestrial laser scanning (TLS), the reason is caused by its polar sampling due to its measurement technology. In both cases, the sampling points are often used for approximating surfaces in order to gain area-based conclusions. Established applications are, e.g., the analysis of ground subsidence with levellings or the area-based deformation analysis with TLS. The configuration of approximation suffers from the irregular spatial distribution of the sampling points even if these sampling points are of sufficient quantity. In combination with limited model knowledge, this can result in biased parameter estimates when modelling surfaces. Hence, the configuration needs to be analyzed and – if necessary – also optimized. Based on these methodical analyses, four aspects can be highlighted with emphasis: 1) It can be exposed that the irregular distribution of sampling points in combination with limited model knowledge results in a suboptimal configuration at approximating surfaces. This analysis rests on partial redundancies and relative differences in partial redundancies. Partial redundancies combine the geometric distribution of the sampling points, the object geometry and the stochastic model of the observations for evaluating the reliability and configuration. 2) For optimizing this configuration at approximating area-based levellings, an algorithm is developed. This algorithm objectively evaluates the spatial distribution of the sampling points dependent on the complexity of the ground subsidence. Existing sampling points are selected based on their importance for the approximation – judged by the configuration analysis. Furthermore, the number and position of additionally required sampling points can be determined for the first time in geodetic network optimization. 3) The parameter estimates of scanned surfaces are often biased and due to the station of the laser scanner. This can be quantified and analyzed based on a configuration analysis considering the partial redundancies. A data reduction – which equals a thinning of the point cloud to gain a regular sampling – minimizes the dependence of the parameter estimates on the laser scanner station. This can also be seen in the improved configuration. 4) An advanced concept for laser scanner based deformation analyses integrates the described aspects of configuration analysis and optimization for a concrete application. In this context, also the aspect of laser scanner calibration is pointed out and integrated into this deformation analysis. These steps altogether imply an immense progress at using terrestrial laser scanners for reliable and accurate deformation analyses. These results are instantaneously relevant for all surface-based approximations demanding high accuracy. Overall, this thesis builds up a fundament for an improved analysis, evaluation and interpretation of area-based approximations based on irregularly sampled surfaces. Embedded in other mentioned methodical aspects, this thesis is of great benefit for the integrated space continualization aspired in engineering geodesy
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