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  • Helmers, Eckard (11)
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Predicting abnormalities in laboratory values of patients in the intensive care unit using different deep learning models: Comparative study (2022)
Ayad, Ahmad ; Hallawa, Ahmed ; Peine, Arne ; Martin, Lukas ; Begic Fazlic, Lejla ; Dartmann, Guido ; Marx, Gernot ; Schmeink, Anke
Background: In recent years, the volume of medical knowledge and health data has increased rapidly. For example, the increased availability of electronic health records (EHRs) provides accurate, up-to-date, and complete information about patients at the point of care and enables medical staff to have quick access to patient records for more coordinated and efficient care. With this increase in knowledge, the complexity of accurate, evidence-based medicine tends to grow all the time. Health care workers must deal with an increasing amount of data and documentation. Meanwhile, relevant patient data are frequently overshadowed by a layer of less relevant data, causing medical staff to often miss important values or abnormal trends and their importance to the progression of the patient’s case. Objective: The goal of this work is to analyze the current laboratory results for patients in the intensive care unit (ICU) and classify which of these lab values could be abnormal the next time the test is done. Detecting near-future abnormalities can be useful to support clinicians in their decision-making process in the ICU by drawing their attention to the important values and focus on future lab testing, saving them both time and money. Additionally, it will give doctors more time to spend with patients, rather than skimming through a long list of lab values. Methods: We used Structured Query Language to extract 25 lab values for mechanically ventilated patients in the ICU from the MIMIC-III and eICU data sets. Additionally, we applied time-windowed sampling and holding, and a support vector machine to fill in the missing values in the sparse time series, as well as the Tukey range to detect and delete anomalies. Then, we used the data to train 4 deep learning models for time series classification, as well as a gradient boosting–based algorithm and compared their performance on both data sets. Results: The models tested in this work (deep neural networks and gradient boosting), combined with the preprocessing pipeline, achieved an accuracy of at least 80% on the multilabel classification task. Moreover, the model based on the multiple convolutional neural network outperformed the other algorithms on both data sets, with the accuracy exceeding 89%. Conclusions: In this work, we show that using machine learning and deep neural networks to predict near-future abnormalities in lab values can achieve satisfactory results. Our system was trained, validated, and tested on 2 well-known data sets to ensure that our system bridged the reality gap as much as possible. Finally, the model can be used in combination with our preprocessing pipeline on real-life EHRs to improve patients’ diagnosis and treatment.
A novel hybrid methodology for anomaly detection in time series (2022)
Begic Fazlic, Lejla ; Hallawa, Ahmed ; Schmeink, Anke ; Lipp, Robert ; Martin, Lukas ; Peine, Arne ; Morgen, Marlies ; Vollmer, Thomas ; Winter, Stefan ; Dartmann, Guido
Numerous research methods have been developed to detect anomalies in the areas of security and risk analysis. In healthcare, there are numerous use cases where anomaly detection is relevant. For example, early detection of sepsis is one such use case. Early treatment of sepsis is cost effective and reduces the number of hospital days of patients in the ICU. There is no single procedure that is sufficient for sepsis diagnosis, and combinations of approaches are needed. Detecting anomalies in patient time series data could help speed the development of some decisions. However, our algorithm must be viewed as complementary to other approaches based on laboratory values and physician judgments. The focus of this work is to develop a hybrid method for detecting anomalies that occur, for example, in multidimensional medical signals, sensor signals, or other time series in business and nature. The novelty of our approach lies in the extension and combination of existing approaches: Statistics, Self Organizing Maps and Linear Discriminant Analysis in a unique and unprecedented way with the goal of identifying different types of anomalies in real-time measurement data and defining the point where the anomaly occurs. The proposed algorithm not only has the full potential to detect anomalies, but also to find real points where an anomaly starts.
Sustainability subjects in university education - Development of a comprehensive indicator system and quantitative analysis of degree programs at German universities (2019)
Helmers, Eckard ; Ilchmann, Fabienne
A new comprehensive evaluation system presented here allows to compare and to quantify education for a sustainable development (ESD) in degree programs. The evaluation is based on a criteria system working with three hierarchic levels. The highest level considers a list of 35 indicator terms. Primarily, the two most popular undergraduate (bachelor’s) degree programs in Germany (mechanical engineering, ME, and business administration, BA) have been reviewed for ESD contents based on the new evaluation scheme. Additionally we reviewed and quantified ESD subjects and their temporal changes in the entire bandwidth of degree programs of a university (Umwelt-Campus Birkenfeld, University of Applied Sciences Trier), back to 1999. Moreover, a spot check on international ME and BA bachelor’s degree programs was performed. Through our reviews, we found a high number of elective classes dedicated to ESD particularly in BA bachelor programs. However, the percentage of compulsory classes related to ESD is relatively low with 5-6 % in both ME and BA programs, respectively. The spot check on degree programs outside Germany revealed similar results. Analysing the time trend at Umwelt-Campus Birkenfeld, a considerable share of ESD that was part of the original diploma degrees was moved to what are now master’s degrees.
Advances and critical aspects in the life-cycle assessment of battery electric cars (2017)
Helmers, Eckard ; Weiss, Martin
Concerns over climate change, air pollution, and oil supply have stimulated the market for battery electric vehicles (BEVs). The environmental impacts of BEVs are typically evaluated through a standardized life-cycle assessment (LCA) methodology. Here, the LCA literature was surveyed with the objective to sketch the major trends and challenges in the impact assessment of BEVs. It was found that BEVs tend to be more energy efficient and less polluting than conventional cars. BEVs decrease exposure to air pollution as their impacts largely result from vehicle production and electricity generation outside of urban areas. The carbon footprint of BEVs, being highly sensitive to the carbon intensity of the electricity mix, may decrease in the nearby future through a shift to renewable energies and technology improvements in general. A minority of LCAs covers impact categories other than carbon footprint, revealing a mixed picture. Up to date little attention is paid so far in LCA to the efficiency advantage of BEVs in urban traffic, the gap between on-road and certified energy consumption, the local exposure to air pollutants and noise and the aging of emissions control technologies in conventional cars. Improvements of BEV components, directed charging, second-life reuse of vehicle batteries, as well as vehicle-to-home and vehicle-to-grid applications will significantly reduce the environmental impacts of BEVs in the future.
The next generation of site-based long-term ecological monitoring: Linking essential biodiversity variables and ecosystem integrity (2018)
Haase, Peter ; Tonkin, Jonathan D. ; Stoll, Stefan ; Burkhard, Benjamin ; Frenzel, Mark ; Geijzendorffer, Ilse R. ; Häuser, Christoph ; Klotz, Stefan ; Kühn, Ingolf ; McDowell, William H. ; Mirtl, Michael ; Müller, Felix ; Musche, Martin ; Penner, Johannes ; Zacharias, Steffen ; Schmeller, Dirk S.
Global change effects on biodiversity and human wellbeing call for improved long-term environmental data as a basis for science, policy and decision making, including increased interoperability, multifunctionality, and harmonization. Based on the example of two global initiatives, the International Long-Term Ecological Research (ILTER) network and the Group on Earth Observations Biodiversity Observation Network (GEO BON), we propose merging the frameworks behind these initiatives, namely ecosystem integrity and essential biodiversity variables, to serve as an improved guideline for future site-based long-term research and monitoring in terrestrial, freshwater and coastal ecosystems. We derive a list of specific recommendations of what and how to measure at a monitoring site and call for an integration of sites into co-located site networks across individual monitoring initiatives, and centered on ecosystems. This facilitates the generation of linked comprehensive ecosystem monitoring data, supports synergies in the use of costly infrastructures, fosters cross-initiative research and provides a template for collaboration beyond the ILTER and GEO BON communities.
Meta-analysis of multidecadal biodiversity trends in Europe (2020)
Pilotto, Francesca ; Kühn, Ingolf ; Adrian, Rita ; Alber, Renate ; Alignier, Audrey ; Andrews, Christopher ; Bäck, Jaana ; Barbaro, Luc ; Beaumont, Deborah ; Beenaerts, Natalie ; Benham, Sue ; Boukal, David S. ; Bretagnolle, Vincent ; Camatti, Elisa ; Canullo, Roberto ; Cardoso, Patricia G. ; Ens, Bruno J. ; Everaert, Gert ; Evtimova, Vesela ; Feuchtmayr, Heidrun ; Garcia-Gonzalez, Ricardo ; Gomez Garcia, Daniel ; Grandin, Ulf ; Gutowski, Jerzy M. ; Hadar, Liat ; Halada, Lubos ; Halassy, Melinda ; Hummel, Herman ; Huttunen, Kaisa-Leena ; Jaroszewicz, Bogdan ; Jensen, Thomas C. ; Kalivoda, Henrik ; Kappel Schmidt, Inger ; Kröncke, Ingrid ; Leinonen, Reima ; Martinho, Filipe ; Meesenburg, Henning ; Meyer, Julia ; Minerbi, Stefano ; Monteith, Don ; Nikolov, Boris P. ; Oro, Daniel ; Ozolins, Davis ; Padedda, Bachisio M. ; Pallett, Denise ; Pansera, Marco ; Pardal, Miguel Angelo ; Petriccione, Bruno ; Pipan, Tanja ; Pöyry, Juha ; Schäfer, Stefanie M. ; Schaub, Marcus ; Schneider, Susanne C. ; Skuja, Agnija ; Soetaert, Karline ; Springe, Gunta ; Stanchev, Radoslav ; Stockan, Jenni A. ; Stoll, Stefan ; Sundqvist, Lisa ; Thimonier, Anne ; Van Hoey, Gert ; Van Ryckegem, Gunther ; Visser, Marcel E. ; Vorhauser, Samuel ; Haase, Peter
Local biodiversity trends over time are likely to be decoupled from global trends, as local processes may compensate or counteract global change. We analyze 161 long-term biological time series (15–91 years) collected across Europe, using a comprehensive dataset comprising ~6,200 marine, freshwater and terrestrial taxa. We test whether (i) local long-term biodiversity trends are consistent among biogeoregions, realms and taxonomic groups, and (ii) changes in biodiversity correlate with regional climate and local conditions. Our results reveal that local trends of abundance, richness and diversity differ among biogeoregions, realms and taxonomic groups, demonstrating that biodiversity changes at local scale are often complex and cannot be easily generalized. However, we find increases in richness and abundance with increasing temperature and naturalness as well as a clear spatial pattern in changes in community composition (i.e. temporal taxonomic turnover) in most biogeoregions of Northern and Eastern Europe.
Eye fluke infection changes diet composition in juvenile European perch (Perca fluviatilis) (2021)
Vivas Munoz, Jenny C. ; Feld, Christian K. ; Hilt, Sabine ; Manfrin, Alessandro ; Nachev, Milen ; Köster, Daniel ; Jochmann, Maik A. ; Schmidt, Torsten C. ; Sures, Bernd ; Zikova, Andrea ; Knopf, Klaus
Intraspecific diet specialization, usually driven by resource availability, competition and predation, is common in natural populations. However, the role of parasites on diet specialization of their hosts has rarely been studied. Eye flukes can impair vision ability of their hosts and have been associated with alterations of fish feeding behavior. Here it was assessed whether European perch (Perca fluviatilis) alter their diet composition as a consequence of infection with eye flukes. Young-of-the-year (YOY) perch from temperate Lake Müggelsee (Berlin, Germany) were sampled in two years, eye flukes counted and fish diet was evaluated using both stomach content and stable isotope analyses. Perch diet was dominated by zooplankton and benthic macroinvertebrates. Both methods indicated that with increasing eye fluke infection intensity fish had a more selective diet, feeding mainly on the benthic macroinvertebrate Dikerogammarus villosus, while less intensively infected fish appeared to be generalist feeders showing no preference for any particular prey type. Our results show that infection with eye flukes can indirectly affect interaction of the host with lower trophic levels by altering the diet composition and highlight the underestimated role of parasites in food web studies.
Development and validation of a reinforcement learning algorithm to dynamically optimize mechanical ventilation in critical care (2021)
Peine, Arne ; Hallawa, Ahmed ; Bickenbach, Johannes ; Dartmann, Guido ; Begic Fazlic, Lejla ; Schmeink, Anke ; Ascheid, Gerd ; Thiemermann, Christoph ; Schuppert, Andreas ; Kindle, Ryan ; Celi, Leo ; Marx, Gernot ; Martin, Lukas
The aim of this work was to develop and evaluate the reinforcement learning algorithm VentAI, which is able to suggest a dynamically optimized mechanical ventilation regime for critically-ill patients. We built, validated and tested its performance on 11,943 events of volume-controlled mechanical ventilation derived from 61,532 distinct ICU admissions and tested it on an independent, secondary dataset (200,859 ICU stays; 25,086 mechanical ventilation events). A patient “data fingerprint” of 44 features was extracted as multidimensional time series in 4-hour time steps. We used a Markov decision process, including a reward system and a Q-learning approach, to find the optimized settings for positive end-expiratory pressure (PEEP), fraction of inspired oxygen (FiO2) and ideal body weight-adjusted tidal volume (Vt). The observed outcome was in-hospital or 90-day mortality. VentAI reached a significantly increased estimated performance return of 83.3 (primary dataset) and 84.1 (secondary dataset) compared to physicians’ standard clinical care (51.1). The number of recommended action changes per mechanically ventilated patient constantly exceeded those of the clinicians. VentAI chose 202.9% more frequently ventilation regimes with lower Vt (5–7.5 mL/kg), but 50.8% less for regimes with higher Vt (7.5–10 mL/kg). VentAI recommended 29.3% more frequently PEEP levels of 5–7 cm H2O and 53.6% more frequently PEEP levels of 7–9 cmH2O. VentAI avoided high (>55%) FiO2 values (59.8% decrease), while preferring the range of 50–55% (140.3% increase). In conclusion, VentAI provides reproducible high performance by dynamically choosing an optimized, individualized ventilation strategy and thus might be of benefit for critically ill patients.
Temperature drives variation in flying insect biomass across a German malaise trap network (2022)
Welti, Ellen A. R. ; Zajicek, Petr ; Frenzel, Mark ; Ayasse, Manfred ; Bornholdt, Tim ; Buse, Jörn ; Classen, Alice ; Dziock, Frank ; Engelmann, Rolf A. ; Englmeier, Jana ; Fellendorf, Martin ; Förschler, Marc I. ; Fricke, Ute ; Ganuza, Cristina ; Hippke, Mathias ; Hoenselaar, Günter ; Kaus-Thiel, Andrea ; Kerner, Janika ; Kilian, Daniela ; Mandery, Klaus ; Marten, Andreas ; Monaghan, Michael T. ; Morkel, Carsten ; Müller, Jörg ; Puffpaff, Stephanie ; Redlich, Sarah ; Richter, Ronny ; Rojas-Botero, Sandra ; Scharnweber, Tobias ; Scheiffarth, Gregor ; Schmidt Yanez, Paul ; Schumann, Rhena ; Seibold, Sebastian ; Steffan-Dewenter, Ingolf ; Stoll, Stefan ; Tobisch, Cynthia ; Twietmeyer, Sönke ; Uhler, Johannes ; Vogt, Juliane ; Weis, Dirk ; Weisser, Wolfgang W. ; Wilmking, Martin ; Haase, Peter
1. Among the many concerns for biodiversity in the Anthropocene, recent reports of flying insect loss are particularly alarming, given their importance as pollinators, pest control agents, and as a food source. Few insect monitoring programmes cover the large spatial scales required to provide more generalizable estimates of insect responses to global change drivers. 2. We ask how climate and surrounding habitat affect flying insect biomass using data from the first year of a new monitoring network at 84 locations across Germany comprising a spatial gradient of land cover types from protected to urban and crop areas. 3. Flying insect biomass increased linearly with temperature across Germany. However, the effect of temperature on flying insect biomass flipped to negative in the hot months of June and July when local temperatures most exceeded long-term averages. 4. Land cover explained little variation in insect biomass, but biomass was lowest in forests. Grasslands, pastures, and orchards harboured the highest insect biomass. The date of peak biomass was primarily driven by surrounding land cover, with grasslands especially having earlier insect biomass phenologies. 5. Standardised, large-scale monitoring provides key insights into the underlying processes of insect decline and is pivotal for the development of climate-adapted strategies to promote insect diversity. In a temperate climate region, we find that the positive effects of temperature on flying insect biomass diminish in a German summer at locations where temperatures most exceeded long-term averages. Our results highlight the importance of local adaptation in climate change-driven impacts on insect communities.
Influence of plastic recycling: A feasibility study for additive manufacturing using glycol modified polyethylene terephthalate (PETG) (2022)
Bremer, Mats ; Janoschek, Lukas ; Kaschta, Denis ; Schneider, Nick ; Wahl, Michael
This paper presents a feasibility study for the production of recycled glycol modified polyethylene terephthalate (PETG) material for additive manufacturing. Past studies showed a variety of results for the recycling of 3D-printing material, therefore the precise effect on the material properties is not completely clear. For this work, PETG waste of the same grade was recycled once and further processed into 3D printing filament. The study compares three blend ratios between purchased plastic pellets and recycled pellets to determine the degradation effect of one recycling cycle and possible blend ratios to counter these effects. Furthermore, the results include a commercially available filament. The comparison uses the filament diameter, the dimensional accuracy of the printed test specimen and mechanical properties as quality criteria. The study shows that the recycled material has a minor decrease concerning the tensile strength and Young’s modulus.
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