Jacobs University
  • Bremen, Bremen, Germany
Recent publications
The use of Environmental Microorganisms (EMs) offers a highly efficient, low cost and harmless remedy to environmental pollution, by monitoring and decomposing of pollutants. This relies on how the EMs are correctly segmented and identified. With the aim of enhancing the segmentation of weakly visible EM images which are transparent, noisy and have low contrast, a Pairwise Deep Learning Feature Network (PDLF-Net) is proposed in this study. The use of PDLFs enables the network to focus more on the foreground (EMs) by concatenating the pairwise deep learning features of each image to different blocks of the base model SegNet. Leveraging the Shi and Tomas descriptors, we extract each image’s deep features on the patches, which are centred at each descriptor using the VGG-16 model. Then, to learn the intermediate characteristics between the descriptors, pairing of the features is performed based on the Delaunay triangulation theorem to form pairwise deep learning features. In this experiment, the PDLF-Net achieves outstanding segmentation results of 89.24%, 63.20%, 77.27%, 35.15%, 89.72%, 91.44% and 89.30% on the accuracy, IoU, Dice, VOE, sensitivity, precision and specificity, respectively.
Background This study aimed to identify latent moderate-to-vigorous intensity physical activity (MVPA) and sedentary behavior (SB) trajectories in older adults participating in a randomized intervention trial and to explore associations with baseline social-cognitive predictors. Methods Data were assessed at baseline (T0, participants were inactive or had recently become active), after a ten-week physical activity intervention (T1), and a second 24-week intervention phase (T2). Latent class growth analysis was used on accelerometer-assessed weekly MVPA and daily SB, respectively ( n = 215 eligible participants). Activity changes within trajectory classes and baseline social-cognitive predictor differences between trajectory classes were analyzed. Results A “stable insufficient MVPA” ( n = 197, p for difference in MVPA level at T0 and T2 ( p T0-T2 ) = .789, effect size (Cohen’s d ) = .03) and a “stable high MVPA” trajectory ( n = 18, p T0-T2 = .137, d = .39), as well as a “slightly decreasing high SB” ( n = 63, p for difference in SB ( p T0-T2 ) = .022, d = .36) and a “slightly increasing moderate SB” trajectory ( n = 152, p T0-T2 = .019, d = .27) emerged. Belonging to the “stable high MVPA” trajectory was associated with higher action planning levels compared to the “stable insufficient MVPA” trajectory ( M = 5.46 versus 4.40, d = .50). Belonging to the “decreasing high SB” trajectory was associated with higher action self-efficacy levels compared to the “increasing moderate SB” trajectory ( M = 5.27 versus 4.72, d = .33). Conclusions Change occurred heterogeneously in latent (not directly observed) subgroups, with significant positive trajectories only observed in the highly sedentary. Trial registration German Registry of Clinical Trials, DRKS00016073 , Registered 10 January 2019.
Cocoa products have a remarkable chemical and sensory complexity. However, in contrast to other fermentation processes in the food industry, cocoa bean fermentation is left essentially uncontrolled and is devoid of standardization. Questions of food authenticity and food quality are hence particularly challenging for cocoa. Here we provide an illustration how network science can support food fingerprinting and food authenticity research. Using a large dataset of 140 cocoa samples comprising three cocoa fermentation/processing stages and eight countries, we obtain correlation networks between the cocoa samples by computing measures of pairwise correlation from their liquid chromatography-mass spectrometry (LC-MS) profiles. We find that the topology of correlation networks derived from untargeted LC-MS profiles is indicative of the fermentation and processing stage as well as the origin country of cocoa samples. Progressively increasing the correlation threshold firstly reveals network clusters based on processing stage and later country-based clusters. We present both, qualitative and quantitative evidence through network visualization, network statistics and concepts from machine learning. In our view, this network-based approach for classifying mass spectrometry data has broad applicability beyond cocoa.
Reinforcement learning (RL) is capable of sophisticated motion planning and control for robots in uncertain environments. However, state-of-the-art deep RL approaches typically lack safety guarantees, especially when the robot and environment models are unknown. To justify widespread deployment, robots must respect safety constraints without sacrificing performance. Thus, we propose a Black-box Reachability-based Safety Layer (BRSL) with three main components: (1) data-driven reachability analysis for a black-box robot model, (2) a trajectory rollout planner that predicts future actions and observations using an ensemble of neural networks trained online, and (3) a differentiable polytope collision check between the reachable set and obstacles that enables correcting unsafe actions. In simulation, BRSL outperforms other state-of-the-art safe RL methods on a Turtlebot 3, a quadrotor, a trajectory-tracking point mass, and a hexarotor in wind with an unsafe set adjacent to the area of highest reward.
Betriebliche Gesundheitsförderung, die auf gesunde Ernährung und Bewegung abzielt, ist effektiv, um Verhalten zu ändern und die Gesundheit der Mitarbeiterinnen und Mitarbeiter sowie den wirtschaftlichen Erfolg des Betriebes zu sichern. In diesem Kapitel wird eine Übersicht gegeben, welche Ansätze es bereits gibt, damit Mitarbeiterinnen und Mitarbeiter sich gesünder verhalten, d. h. sich gesund ernähren und mehr bewegen und wie sie gesetzlich fundiert sind. Neuere Ansätze können bereits bestehende Angebote innovativer und wirksamer gestalten. Insbesondere das theoretische Verständnis und die Kenntnis von Techniken kann helfen zu verstehen, warum einige Angebote von Mitarbeiterinnen und Mitarbeitern angenommen werden und wirken, und andere nicht bzw. wie sie verbessert werden sollten. Daraus ergeben sich auch Empfehlungen, wie Maßnahmen sinnvoll implementiert werden sollten, damit sie von den Mitarbeiterinnen und Mitarbeitern akzeptiert werden und nachhaltig wirksam sind.
Purpose of Review This review provides an overview of the current state of the art in Underwater Human-Robot Interaction (U-HRI), which is an area that is quite different from standard Human-Robot Interaction (HRI). This is due to several reasons. First of all, there are the particular properties of water as a medium, e.g., the strong attenuation of radio-frequency (RF) signals or the physics of underwater image formation. Second, divers are bound to special equipment, e.g., the breathing apparatus, which makes, for example, speech recognition challenging, if not impossible. Third, typical collaborative marine missions primarily requires a high amount of communication from the diver to the robot, which accordingly receives a lot of attention in U-HRI research. Recent Findings The use of gestures for diver-to-robot communication has turned out to be a quite promising approach for U-HRI as gestures are already a standard form of communication among divers. For the gesture front-ends, i.e., the part dealing with the machine perception of individual signs, Deep Learning (DL) has become to be a very prominent tool. Summary Human divers and marine robots have many complementary skills. There is hence a large potential for U-HRI. But while there is some clear progress in the field, the full potential of U-HRI is far from being exploited, yet.
The toxicity of lead (Pb) in halide-based hybrid perovskite materials stands in the way of their more extensive use, despite their excellent optical properties, high stability and very good photoconversion...
The formation of layered mounds on Mars remains a major topic of debate, with the relationship between their deposition and chemical alteration a major aspect still to be constrained. The association these deposits have with hydrated minerals indicates aqueous processes were active in their past, however the extent and duration of this aqueous period has yet to be fully realized. We studied compositional, stratigraphical, and structural characteristics of two separate layered deposits within Becquerel crater, Arabia Terra, to constrain their origins and the intensity of past aqueous activity. We find that due to key differences in composition, layering, and deformation between the two deposits, the timing of important depositional changes within Becquerel can be identified. We propose a scenario involving differences in fluid expulsion intensity and water level between the two layered deposits, in which diverse depositional and post-depositional environments were able to form. Furthermore, internal collapsing and deformation of the main mound might reflect that fluid upwelling persisted below the mound after formation. Determining the relationship between these two deposits is an important step in unraveling the past climate of Arabia Terra, and more broadly Mars. The evidence of protracted fluid expulsion represents a unique opportunity for future missions searching for signs of past life.
Objectives To develop a new dye formulation for vitreoretinal surgery, which shows increased transparency for better intraoperative handling with better parameters important for use. Methods and analysis A new blue dye, DDG, was synthesised and tested for toxicity and staining. Diglycerol as new density-increasing additive was identified, and its toxicity and lack of influence of the staining with trypan blue (TB) on a collagen membrane as model for the epiretinal membrane was determined. Transparency of the dye solution was evaluated. Results DDG is as alternative to Brilliant Blue G (BBG), with good staining properties for interna limitans models, and a good safety profile. Diglycerol is a new non-toxic additive replacing PEG3350, with reduced viscosity and no reduction in staining, allowing the reduction of TB to achieve the same staining level of the collagen membrane by 40%, with greater transparency of the dye solution and reduced viscosity. Both factors should facilitate a safe removal during surgery. Conclusion A new dye preparation with improved performance in comparison to marketed combinations of BBG and TB was developed. Its reduced TB concentration and viscosity with maintained density allow better tolerance and handling.
Zusammenfassung Das Jahr 2021 hat in Deutschland neuen Schwung in die Bemühungen zum Klimaschutz gebracht. Die Novelle des Klimaschutzgesetzes schreibt eine Reduktion der Treibhausgasemissionen um 65 % bis zum Jahr 2030 gegenüber 1990 fest. Maßgeblich dazu beitragen soll ein massiver Ausbau der Stromerzeugung aus erneuerbaren Energien. Nach Verschärfung der Klimaschutzmaßnahmen stellt sich die Frage, ob das bisherige Strommarktdesign und die damit einhergehenden Vergütungsregeln für die Stromerzeugung auch bei einem von erneuerbaren Energien dominierten Strommarkt weiterhin geeignet sind, um die im Energiewirtschaftsgesetz festgeschriebenen Ziele der Versorgungssicherheit und Preisgünstigkeit bestmöglich zu erreichen.
Tailored transmembrane alpha-helical pores with desired structural and functional versatility have promising applications in nanobiotechnology. Herein, we present a transmembrane pore DpPorA, based on the natural pore PorACj, built from D-amino acid α-helical peptides. Using single-channel current recordings, we show that DpPorA peptides self-assemble into uniform cation-selective pores in lipid membranes and exhibit properties distinct from their L-amino acid counterparts. DpPorA shows resistance to protease and acts as a functional nanopore sensor to detect cyclic sugars, polypeptides, and polymers. Fluorescence imaging reveals that DpPorA forms well-defined pores in giant unilamellar vesicles facilitating the transport of hydrophilic molecules. A second D-amino acid peptide based on the polysaccharide transporter Wza forms transient pores confirming sequence specificity in stable, functional pore formation. Finally, molecular dynamics simulations reveal the specific alpha-helical packing and surface charge conformation of the D-pores consistent with experimental observations. Our findings will aid the design of sophisticated pores for single-molecule sensing related technologies. Alpha-helix nanopores have a range of potential applications and the inclusion of non-natural amino acids allows for modification. Here, the authors report on the creation of alpha-helix pores using D-amino acids and show the pores formed, have different properties to the L-counterparts and were resistant to proteases.
(1) Background: Patient safety is a pressing issue in healthcare. Besides economical and organizational issues, human factors play a crucial role in providing safe care. Safe and clear communication on both the healthcare workers’ and patients’ sides contribute to the avoidance of medical errors and increase patients’ and healthcare workers’ satisfaction. Globally, the incidence of experiencing at least one adverse event in obstetrics is about 10%, of which half are classified as preventable. According to international research, improving communication skills may decrease preventable adverse events. The research question was to what extent communication training for pregnant women impacts the quality of communication and mutual understanding during birth. (2) Methods: Communication interventions with pregnant women were conducted in two German university obstetric departments in a mixed methods research design, based on the Health Action Process Approach. The online classes covered the awareness of personal wishes, the understanding and usage of communication strategies, self-efficacy and empathy. This study presents the qualitative results. Out of 142 mothers who answered two questionnaires before the communication training and after the birth, 24 in-depth semistructured interviews were conducted to explore the subjective impact of the communication training. The results were analyzed with qualitative content analysis. (3) Results: The majority of participants felt incentivized to be aware of their personal wishes for birth and to express them. Perceived positive experiences with sufficient competency in communication, empathy and mutual understanding outweighed negative treatments and experiences in the hospital, some of which could be attributed to structural problems. (4) Discussion: The reported positive effects of the communication training underline the need but also the potential for communication lessons to reflect and improve communication skills in obstetrics. However, negative experiences due to structural problems in the healthcare system may be facilitated by communication skills but not solved.
Zusammenfassung Auf digitalen Märkten besteht, wer die zugrundeliegenden digitalen, unternehmensbezogenen oder akteursübergreifenden institutionellen Arrangements versteht und aktiv gestaltet. Dazu werden ausgereifte, von Forschung und Praxis diskutierte und gemeinsam weiter entwickelte Methoden zum Design digitaler Plattformen, Geschäftsmodelle und Service-Ökosysteme benötigt. Einen gemeinschaftlichen Aufschlag hierzu macht der folgende Artikel. Er entstand aus einem offenen Aufruf in der Wirtschaftsinformatik-Community – über Mailing-Listen und soziale Medien. Im Ergebnis führen sieben Forschergruppen (oder einzelne Forscher und Forscherinnen) ihre aktuellen Erkenntnisse zu diesem Thema zusammen.
Background Web-based multiple health behavior change (MHBC) interventions have demonstrated effectiveness in promoting physical activity (PA) and fruit and vegetable consumption (FVC) among Chinese college students. However, there is limited research examining their effects on promoting a healthy lifestyle (ie, adhering to both PA and FVC behavioral recommendations) among Chinese college students. In addition, the salient psychosocial mediators of successful MHBC interventions need to be researched. Objective This study aims to examine the effectiveness of a previous 8-week web-based MHBC program for promoting a healthy lifestyle and enhancing the psychosocial determinants (intention, self-efficacy, planning, and social support) of behavior change among Chinese college students. Furthermore, the study aims to identify whether changes in these psychosocial determinants mediate intervention effectiveness on the immediate and sustained lifestyle changes. Methods This was a secondary analysis for a 3-arm randomized controlled trial. Chinese college students (N=552) were randomly assigned to 1 of 3 groups: a PA-first group (4-week PA intervention followed by 4-week FVC intervention), an FVC-first group (4-week FVC intervention followed by 4-week PA intervention), and a placebo control group. The intervention content was designed based on the health action process approach model. Data for analyses were collected at baseline (T0), postintervention assessment (T1), and 12-week follow-up assessment (T2). Results At baseline, 13.9% (77/552) of the participants maintained a healthy lifestyle. After 8 weeks, more (200/552, 36.2%) participants achieved a healthy lifestyle. PA-first and FVC-first groups were, respectively, 3.24 times and 5 times more likely to adopt a healthy lifestyle than the control group at T1. After 12 weeks, 35.5% (196/552) of the participants adopted a healthy lifestyle. Intervention groups were approximately 2.99 times (PA first) and 4.07 times (FVC first) more likely to adopt a healthy lifestyle than the control group at T2. Intervention effects favored both intervention groups in self-efficacy and planning for PA and in intention and planning for FVC compared with the control condition. In addition, changes in PA self-efficacy and FVC intention mediated intervention effectiveness on the immediate lifestyle change after 8 weeks. Changes in FVC intention were identified as a salient mediator for facilitating sustained lifestyle change after 12 weeks. Conclusions This study provides empirical evidence for the effectiveness of an 8-week theory- and web-based MHBC intervention program on promoting a healthy lifestyle, self-efficacy and planning for PA, and intention and planning for FVC among Chinese college students. These research findings add new knowledge to the underlying psychosocial mechanisms of successful MHBC interventions. Overall, this study has considerable implications for future web-based MHBC research and practice in terms of addressing PA self-efficacy and FVC intention and helping students to adopt and maintain a healthy lifestyle independently of whether PA or FVC is addressed first. Trial Registration ClinicalTrials.gov NCT03627949; https://clinicaltrials.gov/ct2/show/NCT03627949
For climate-change impact studies at the catchment scale, meteorological variables are typically extracted from ensemble simulations provided by global and regional climate models, which are then downscaled and bias-adjusted for each study site. For bias adjustment, different statistical methods that re-scale climate model outputs have been suggested in the scientific literature. They range from simple univariate methods that adjust each meteorological variable individually, to more complex and more demanding multivariate methods that take existing relationships between meteorological variables into consideration. Over the past decade, several attempts have been made to evaluate such methods in various regions. There is, however, still no guidance for choosing appropriate bias adjustment methods for a study at hand. In particular, the question whether the benefits of potentially improved adjustments outweigh the cost of increased complexity, remains unanswered. This paper presents a comprehensive evaluation of the performance of two commonly used univariate and two multivariate bias adjustment methods in reproducing numerous univariate, multivariate and temporal features of precipitation and temperature series in different catchments in Sweden. The paper culminates in a discussion on trade-offs between the potential benefits (i.e., skills and added value) and disadvantages (complexity and computational demand) of each method to offer plausible, defensible and actionable insights from the standpoint of climate-change impact studies in high latitudes. We concluded that all selected bias adjustment methods generally improved the raw climate model simulations, but that not a single method consistently outperformed the other methods. There were, however, differences in the methods' performance for particular statistical features, indicating that other practical aspects such as computational time and heavy theoretical requirements should also be taken into consideration when choosing an appropriate bias adjustment method.
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1,720 members
Ben Godde
  • Psychology and Methods
Adalbert Franz Wilhelm
  • Psychology and Methods
Anuj Sehgal
  • CASE - Center for Advanced Systems Engineering
Arvid Kappas
  • Psychology and Methods
Campus Ring 1, 28759, Bremen, Bremen, Germany
Head of institution
Prof. Dr. Michael Hülsmann