The OpenModelica integrated environment for modeling, simulation, and model-based development

OpenModelica is a unique large-scale integrated open-source Modelica- and FMI-based modeling, simulation, optimization, model-based analysis and development environment. Moreover, the OpenModelica environment provides a number of facilities such as debugging; optimization; visualization and 3D animation; web-based model editing and simulation; scripting from Modelica, Python, Julia, and Matlab; efficient simulation and co-simulation of FMI-based models; compilation for embedded systems; Modelica- UML integration; requirement verification; and generation of parallel code for multi-core architectures. The environment is based on the equation-based object-oriented Modelica language and currently uses the MetaModelica extended version of Modelica for its model compiler implementation. This overview paper gives an up-to-date description of the capabilities of the system, short overviews of used open source symbolic and numeric algorithms with pointers to published literature, tool integration aspects, some lessons learned, and the main vision behind its development.Fil: Fritzson, Peter. Linköping University; SueciaFil: Pop, Adrian. Linköping University; SueciaFil: Abdelhak, Karim. Fachhochschule Bielefeld; AlemaniaFil: Asghar, Adeel. Linköping University; SueciaFil: Bachmann, Bernhard. Fachhochschule Bielefeld; AlemaniaFil: Braun, Willi. Fachhochschule Bielefeld; AlemaniaFil: Bouskela, Daniel. Electricité de France; FranciaFil: Braun, Robert. Linköping University; SueciaFil: Buffoni, Lena. Linköping University; SueciaFil: Casella, Francesco. Politecnico di Milano; ItaliaFil: Castro, Rodrigo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Investigación en Ciencias de la Computación. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Investigación en Ciencias de la Computación; ArgentinaFil: Franke, Rüdiger. Abb Group; AlemaniaFil: Fritzson, Dag. Linköping University; SueciaFil: Gebremedhin, Mahder. Linköping University; SueciaFil: Heuermann, Andreas. Linköping University; SueciaFil: Lie, Bernt. University of South-Eastern Norway; NoruegaFil: Mengist, Alachew. Linköping University; SueciaFil: Mikelsons, Lars. Linköping University; SueciaFil: Moudgalya, Kannan. Indian Institute Of Technology Bombay; IndiaFil: Ochel, Lennart. Linköping University; SueciaFil: Palanisamy, Arunkumar. Linköping University; SueciaFil: Ruge, Vitalij. Fachhochschule Bielefeld; AlemaniaFil: Schamai, Wladimir. Danfoss Power Solutions GmbH & Co; AlemaniaFil: Sjolund, Martin. Linköping University; SueciaFil: Thiele, Bernhard. Linköping University; SueciaFil: Tinnerholm, John. Linköping University; SueciaFil: Ostlund, Per. Linköping University; Sueci

An outcome study of severe traumatic head injury using the "Lund therapy" with low-dose prostacyclin

Background: There are two independent head injury outcome studies using the "Lund concept", and both showed a mortality rate of about 10%, and a favourable outcome (Glasgow outcome scale, GOS 4 and 5) of about 70%. The Lund concept aims at controlling intracranial pressure, and improving microcirculation around contusions. Intracranial pressure is controlled by maintaining a normal colloid osmotic pressure and reducing the hydrostatic capillary pressure. Microcirculation is improved by ensuring strict normovolaemia and reducing sympathetic discharge. The endogenous substance prostacyclin with its antiaggregatory/antiadhesive effects may further improve microcirculation, which finds support from a microdialysis-based clinical study and an experimental brain trauma study. The present clinical outcome study aims at evaluating whether the previously obtained good outcome with the Lund therapy can be reproduced, and whether the addition of prostacyclin has any adverse side-effects. Methods: All 31 consecutive patients with severe head injury, Glasgow coma scale (GCS) less than or equal to8, admitted to the University Hospital of Umea during 1998 were included. The Lund therapy including prostacyclin infusion for the first three days at a dose of 0.5 ng kg(-1) min(-1). Outcome was evaluated according to the GOS >10 months after the injury. Results: One patient died, another suffered vegetative state and 7 severe disability. Of the 22 patients with favourable outcome, 19 showed good recovery and 3 moderate disability. No adverse side-effects of prostacyclin were observed. Conclusion: The outcome results from previous studies using the Lund therapy were reproduced, and no adverse side-effects of low-dose prostacyclin were observed

Risk factors for COVID-19-related death, hospitalization and intensive care : a population-wide study of all inhabitants in Stockholm

Since the beginning of the Covid-19 pandemic, the scientific community has explored determinants of Covid 19 disease severity. However, the majority of studies are based on in-hospital patients with high risk of collider- or selection bias. The present investigation details risk factors associated with overall mortality, hospitalization and intensive care unit (ICU) admission in Covid-19 infections, with complete population coverage and high-resolution data on patient characteristics and comorbid conditions This population-based observational study comprises all residents 18 years and older in Stockholm Region-1.8 million inhabitants-using the real-time Covid-19 monitoring framework. The observation period lasted between March 1 to December 31, 2020. Hazard ratios (HR) for risk factors of Covid-19 disease severity were assessed using Cox proportional hazard models. In total, 3322 deaths, 11,508 hospitalizations and 1423 ICU-admissions related to Covid-19 occurred during the study period. Kidney failure, diabetes and obesity increased risk of mortality and so did heart failure and ischemic heart disease. However, atrial fibrillation and hypertension did not. Risk of hospitalization follow a similar pattern, whereas admission to intensive care differs; triage processes where clearly present as certain co-morbid conditions were associated with lower ICU admission. Observed differences in risk of mortality and hospitalization among patients with Covid 19 raise important questions about potentially protective comedication which will be further addressed using the real-time Covid-19 monitoring framework

Linear spin-wave theory of incommensurably modulated magnets

Calculations of linearized theories of spin dynamics encounter difficulties when applied to incommensurable magnetic phases: lack of translational invariance leads to an infinite coupled system of equations. The authors resolve this for the case of a `single-Q' structure by mapping onto the problem of diagonalizing a quasiperiodic Hamiltonian of tight-binding type in one dimension. This allows for calculation of the correlation functions relevant to neutron scattering or magnetic resonance experiments. With the application to the case of a longitudinally modulated magnet a number of new predictions are made: at higher frequency there appear bands of response sharply defined in frequency, but broad in momentum transfer; at low frequencies there is a response maximum at the q vector corresponding to the modulation vector. They discuss generalizations necessary for application to rare-earth magnet

One-Year Survival of Extremely Preterm Infants After Active Perinatal Care in Sweden

Context Up-to-date information on infant survival after extremely preterm birth is needed for assessing perinatal care services, clinical guidelines, and parental counseling. Objective To determine the 1-year survival in all infants born before 27 gestational weeks in Sweden during 2004-2007. Design, Setting, and Patients Population-based prospective observational study of extremely preterm infants (707 live-born and 304 stillbirths) born to 887 mothers in 904 deliveries (102 multiple births) in all obstetric and neonatal units in Sweden from April 1, 2004, to March 31, 2007. Main Outcome Measures Infant survival to 365 days and survival without major neonatal morbidity (intraventricular hemorrhage grade > 2, retinopathy of prematurity stage > 2, periventricular leukomalacia, necrotizing enterocolitis, severe bronchopulmonary dysplasia). Associations between perinatal interventions and survival. Results The incidence of extreme prematurity was 3.3 per 1000 infants. Overall perinatal mortality was 45% (from 93% at 22 weeks to 24% at 26 weeks), with 30% stillbirths, including 6.5% intrapartum deaths. Of live-born infants, 91% were admitted to neonatal intensive care and 70% survived to 1 year of age (95% confidence interval [CI], 67%-73%). The Kaplan-Meier survival estimates for 22, 23, 24, 25, and 26 weeks were 9.8% (95% CI, 4%-23%), 53% ( 95% CI, 44%-63%), 67% (95% CI, 59%-75%), 82% (95% CI, 76%-87%), and 85% ( 95% CI, 81%-90%), respectively. Lower risk of infant death was associated with tocolytic treatment (adjusted for gestational age odds ratio [ OR], 0.43; 95% CI, 0.36-0.52), antenatal corticosteroids (OR, 0.44; 95% CI, 0.24-0.81), surfactant treatment within 2 hours after birth ( OR, 0.47; 95% CI, 0.32-0.71), and birth at a level III hospital (OR, 0.49; 95% CI, 0.32-0.75). Among 1-year survivors, 45% had no major neonatal morbidity. Conclusion During 2004 to 2007, 1-year survival of infants born alive at 22 to 26 weeks of gestation in Sweden was 70% and ranged from 9.8% at 22 weeks to 85% at 26 weeks. JAMA. 2009;301(21):2225-2233 www.jama.co