TY - THES A1 - Hesse, Günter T1 - A benchmark for enterprise stream processing architectures T1 - Ein Benchmark für Architekturen zur Datenstromverarbeitung im Unternehmenskontext N2 - Data stream processing systems (DSPSs) are a key enabler to integrate continuously generated data, such as sensor measurements, into enterprise applications. DSPSs allow to steadily analyze information from data streams, e.g., to monitor manufacturing processes and enable fast reactions to anomalous behavior. Moreover, DSPSs continuously filter, sample, and aggregate incoming streams of data, which reduces the data size, and thus data storage costs. The growing volumes of generated data have increased the demand for high-performance DSPSs, leading to a higher interest in these systems and to the development of new DSPSs. While having more DSPSs is favorable for users as it allows choosing the system that satisfies their requirements the most, it also introduces the challenge of identifying the most suitable DSPS regarding current needs as well as future demands. Having a solution to this challenge is important because replacements of DSPSs require the costly re-writing of applications if no abstraction layer is used for application development. However, quantifying performance differences between DSPSs is a difficult task. Existing benchmarks fail to integrate all core functionalities of DSPSs and lack tool support, which hinders objective result comparisons. Moreover, no current benchmark covers the combination of streaming data with existing structured business data, which is particularly relevant for companies. This thesis proposes a performance benchmark for enterprise stream processing called ESPBench. With enterprise stream processing, we refer to the combination of streaming and structured business data. Our benchmark design represents real-world scenarios and allows for an objective result comparison as well as scaling of data. The defined benchmark query set covers all core functionalities of DSPSs. The benchmark toolkit automates the entire benchmark process and provides important features, such as query result validation and a configurable data ingestion rate. To validate ESPBench and to ease the use of the benchmark, we propose an example implementation of the ESPBench queries leveraging the Apache Beam software development kit (SDK). The Apache Beam SDK is an abstraction layer designed for developing stream processing applications that is applied in academia as well as enterprise contexts. It allows to run the defined applications on any of the supported DSPSs. The performance impact of Apache Beam is studied in this dissertation as well. The results show that there is a significant influence that differs among DSPSs and stream processing applications. For validating ESPBench, we use the example implementation of the ESPBench queries developed using the Apache Beam SDK. We benchmark the implemented queries executed on three modern DSPSs: Apache Flink, Apache Spark Streaming, and Hazelcast Jet. The results of the study prove the functioning of ESPBench and its toolkit. ESPBench is capable of quantifying performance characteristics of DSPSs and of unveiling differences among systems. The benchmark proposed in this thesis covers all requirements to be applied in enterprise stream processing settings, and thus represents an improvement over the current state-of-the-art. N2 - Data Stream Processing Systems (DSPSs) sind eine Schlüsseltechnologie, um kontinuierlich generierte Daten, wie beispielsweise Sensormessungen, in Unternehmensanwendungen zu integrieren. Die durch DSPSs ermöglichte permanente Analyse von Datenströmen kann dabei zur Überwachung von Produktionsprozessen genutzt werden, um möglichst zeitnah auf ungewollte Veränderungen zu reagieren. Darüber hinaus filtern, sampeln und aggregieren DSPSs einkommende Daten, was die Datengröße reduziert und so auch etwaige Kosten für die Datenspeicherung. Steigende Datenvolumen haben in den letzten Jahren den Bedarf für performante DSPSs steigen lassen, was zur Entwicklung neuer DSPSs führte. Während eine große Auswahl an verfügbaren Systemen generell gut für Nutzer ist, stellt es potentielle Anwender auch vor die Herausforderung, das für aktuelle und zukünftige Anforderungen passendste DSPS zu identifizieren. Es ist wichtig, eine Lösung für diese Herausforderung zu haben, da das Austauschen von einem DSPS zu teuren Anpassungen oder Neuentwicklungen der darauf laufenden Anwendungen erfordert, falls für deren Entwicklung keine Abstraktionsschicht verwendet wurde. Das quantitative Vergleichen von DSPSs ist allerdings eine schwierige Aufgabe. Existierende Benchmarks decken nicht alle Kernfunktionalitäten von DSPSs ab und haben keinen oder unzureichenden Tool-Support, was eine objektive Ergebnisberechnung hinsichtlich der Performanz erschwert. Zudem beinhaltet kein Benchmark die Integration von Streamingdaten und strukturierten Geschäftsdaten, was ein besonders für Unternehmen relevantes Szenario ist. Diese Dissertation stellt ESPBench vor, einen neuen Benchmark für Stream Processing-Szenarien im Unternehmenskontext. Der geschäftliche Kontext wird dabei durch die Verbindung von Streamingdaten und Geschäftsdaten dargestellt. Das Design von ESPBench repräsentiert Szenarien der realen Welt, stellt die objektive Berechnung von Benchmarkergebnissen sicher und erlaubt das Skalieren über Datencharakteristiken. Das entwickelte Toolkit des Benchmarks stellt wichtige Funktionalitäten bereit, wie beispielsweise die Automatisierung den kompletten Benchmarkprozesses sowie die Überprüfung der Abfrageergebnisse hinsichtlich ihrer Korrektheit. Um ESPBench zu validieren und die Anwendung weiter zu vereinfachen, haben wir eine Beispielimplementierung der Queries veröffentlicht. Die Implementierung haben wir mithilfe des in Industrie und Wissenschaft eingesetzten Softwareentwicklungsbaukastens Apache Beam durchgeführt, der es ermöglicht, entwickelte Anwendungen auf allen unterstützten DSPSs auszuführen. Den Einfluss auf die Performanz des Verwendens von Apache Beam wird dabei ebenfalls in dieser Arbeit untersucht. Weiterhin nutzen wir die veröffentlichte Beispielimplementierung der Queries um drei moderne DSPSs mit ESPBench zu untersuchen: Apache Flink, Apache Spark Streaming und Hazelcast Jet. Der Ergebnisse der Studie verdeutlichen die Funktionsfähigkeit von ESPBench und dessen Toolkit. ESPBench befähigt Performanzcharakteristiken von DSPSs zu quantifizieren und Unterschiede zwischen Systemen aufzuzeigen. Der in dieser Dissertation vorgestellte Benchmark erfüllt alle Anforderungen, um in Stream Processing-Szenarien im Unternehmenskontext eingesetzt zu werden und stellt somit eine Verbesserung der aktuellen Situation dar. KW - stream processing KW - performance KW - benchmarking KW - dsps KW - espbench KW - benchmark KW - Performanz KW - Datenstromverarbeitung KW - Benchmark Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-566000 ER - TY - JOUR A1 - Mugele, Hendrik A1 - Plummer, Ashley A1 - Baritello, Omar A1 - Towe, Maggie A1 - Brecht, Pia A1 - Mayer, Frank T1 - Accuracy of training recommendations based on a treadmill multistage incremental exercise test JF - PLOS ONE N2 - Competitive runners will occasionally undergo exercise in a laboratory setting to obtain predictive and prescriptive information regarding their performance. The present research aimed to assess whether the physiological demands of lab-based treadmill running (TM) can simulate that of over-ground (OG) running using a commonly used protocol. Fifteen healthy volunteers with a weekly mileage of ≥ 20 km over the past 6 months and treadmill experience participated in this cross-sectional study. Two stepwise incremental tests until volitional exhaustion was performed in a fixed order within one week in an Outpatient Clinic research laboratory and outdoor athletic track. Running velocity (IATspeed), heart rate (IATHR) and lactate concentration at the individual anaerobic threshold (IATbLa) were primary endpoints. Additionally, distance covered (DIST), maximal heart rate (HRmax), maximal blood lactate concentration (bLamax) and rate of perceived exertion (RPE) at IATspeed were analyzed. IATspeed, DIST and HRmax were not statistically significantly different between conditions, whereas bLamax and RPE at IATspeed showed statistical significance (p < 0.05). Apart from RPE at IATspeed, IATspeed, DIST, HRmax and bLamax strongly correlate between conditions (r = 0.815–0.988). High reliability between conditions provides strong evidence to suggest that running on a treadmill are physiologically comparable to that of OG and that training recommendations and be made with assurance. KW - individual anaerobic threshold KW - lactate threshold KW - soccer players KW - performance KW - validity KW - reliability KW - runners Y1 - 2018 U6 - https://doi.org/10.1371/journal.pone.0204696 SN - 1932-6203 VL - 13 IS - 10 SP - 1 EP - 12 PB - PLOS CY - San Francisco ER - TY - GEN A1 - Mugele, Hendrik A1 - Plummer, Ashley A1 - Baritello, Omar A1 - Towe, Maggie A1 - Brecht, Pia A1 - Mayer, Frank T1 - Accuracy of training recommendations based on a treadmill multistage incremental exercise test T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - Competitive runners will occasionally undergo exercise in a laboratory setting to obtain predictive and prescriptive information regarding their performance. The present research aimed to assess whether the physiological demands of lab-based treadmill running (TM) can simulate that of over-ground (OG) running using a commonly used protocol. Fifteen healthy volunteers with a weekly mileage of ≥ 20 km over the past 6 months and treadmill experience participated in this cross-sectional study. Two stepwise incremental tests until volitional exhaustion was performed in a fixed order within one week in an Outpatient Clinic research laboratory and outdoor athletic track. Running velocity (IATspeed), heart rate (IATHR) and lactate concentration at the individual anaerobic threshold (IATbLa) were primary endpoints. Additionally, distance covered (DIST), maximal heart rate (HRmax), maximal blood lactate concentration (bLamax) and rate of perceived exertion (RPE) at IATspeed were analyzed. IATspeed, DIST and HRmax were not statistically significantly different between conditions, whereas bLamax and RPE at IATspeed showed statistical significance (p < 0.05). Apart from RPE at IATspeed, IATspeed, DIST, HRmax and bLamax strongly correlate between conditions (r = 0.815–0.988). High reliability between conditions provides strong evidence to suggest that running on a treadmill are physiologically comparable to that of OG and that training recommendations and be made with assurance. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 477 KW - individual anaerobic threshold KW - lactate threshold KW - soccer players KW - performance KW - validity KW - reliability KW - runners Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-419697 SN - 1866-8364 IS - 477 ER - TY - JOUR A1 - Werfelli, Hanen A1 - Hammami, Raouf A1 - Selmi, Mohamed Amine A1 - Selmi, Walid A1 - Gabrilo, Goran A1 - Clark, Cain C. T. A1 - Duncan, Michael A1 - Sekulic, Damir A1 - Granacher, Urs A1 - Rebai, Haithem T1 - Acute Effects of Different Plyometric and Strength Exercises on Balance Performance in Youth Weightlifters JF - Frontiers in Physiology N2 - Background: High-intensity muscle actions have the potential to temporarily improve the performance which has been denoted as postactivation performance enhancement. Objectives: This study determined the acute effects of different stretch-shortening (fast vs. low) and strength (dynamic vs. isometric) exercises executed during one training session on subsequent balance performance in youth weightlifters. Materials and Methods: Sixteen male and female young weightlifters, aged 11.3±0.6years, performed four strength exercise conditions in randomized order, including dynamic strength (DYN; 3 sets of 3 repetitions of 10 RM) and isometric strength exercises (ISOM; 3 sets of maintaining 3s of 10 RM of back-squat), as well as fast (FSSC; 3 sets of 3 repetitions of 20-cm drop-jumps) and slow (SSSC; 3 sets of 3 hurdle jumps over a 20-cm obstacle) stretch-shortening cycle protocols. Balance performance was tested before and after each of the four exercise conditions in bipedal stance on an unstable surface (i.e., BOSU ball with flat side facing up) using two dependent variables, i.e., center of pressure surface area (CoP SA) and velocity (CoP V). Results: There was a significant effect of time on CoP SA and CoP V [F(1,60)=54.37, d=1.88, p<0.0001; F(1,60)=9.07, d=0.77, p=0.003]. In addition, a statistically significant effect of condition on CoP SA and CoP V [F(3,60)=11.81, d=1.53, p<0.0001; F(3,60)=7.36, d=1.21, p=0.0003] was observed. Statistically significant condition-by-time interactions were found for the balance parameters CoP SA (p<0.003, d=0.54) and CoP V (p<0.002, d=0.70). Specific to contrast analysis, all specified hypotheses were tested and demonstrated that FSSC yielded significantly greater improvements than all other conditions in CoP SA and CoP V [p<0.0001 (d=1.55); p=0.0004 (d=1.19), respectively]. In addition, FSSC yielded significantly greater improvements compared with the two conditions for both balance parameters [p<0.0001 (d=2.03); p<0.0001 (d=1.45)]. Conclusion: Fast stretch-shortening cycle exercises appear to be more effective to improve short-term balance performance in young weightlifters. Due to the importance of balance for overall competitive achievement in weightlifting, it is recommended that young weightlifters implement dynamic plyometric exercises in the fast stretch-shortening cycle during the warm-up to improve their balance performance. KW - postural stability KW - conditioning exercise KW - adolescents KW - performance KW - weightlifting Y1 - 2021 U6 - https://doi.org/10.3389/fphys.2021.716981 SN - 1664-042X VL - 12 PB - Frontiers Research Foundation CY - Lausanne ER - TY - GEN A1 - Werfelli, Hanen A1 - Hammami, Raouf A1 - Selmi, Mohamed Amine A1 - Selmi, Walid A1 - Gabrilo, Goran A1 - Clark, Cain C. T. A1 - Duncan, Michael A1 - Sekulic, Damir A1 - Granacher, Urs A1 - Rebai, Haithem T1 - Acute Effects of Different Plyometric and Strength Exercises on Balance Performance in Youth Weightlifters T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - Background: High-intensity muscle actions have the potential to temporarily improve the performance which has been denoted as postactivation performance enhancement. Objectives: This study determined the acute effects of different stretch-shortening (fast vs. low) and strength (dynamic vs. isometric) exercises executed during one training session on subsequent balance performance in youth weightlifters. Materials and Methods: Sixteen male and female young weightlifters, aged 11.3±0.6years, performed four strength exercise conditions in randomized order, including dynamic strength (DYN; 3 sets of 3 repetitions of 10 RM) and isometric strength exercises (ISOM; 3 sets of maintaining 3s of 10 RM of back-squat), as well as fast (FSSC; 3 sets of 3 repetitions of 20-cm drop-jumps) and slow (SSSC; 3 sets of 3 hurdle jumps over a 20-cm obstacle) stretch-shortening cycle protocols. Balance performance was tested before and after each of the four exercise conditions in bipedal stance on an unstable surface (i.e., BOSU ball with flat side facing up) using two dependent variables, i.e., center of pressure surface area (CoP SA) and velocity (CoP V). Results: There was a significant effect of time on CoP SA and CoP V [F(1,60)=54.37, d=1.88, p<0.0001; F(1,60)=9.07, d=0.77, p=0.003]. In addition, a statistically significant effect of condition on CoP SA and CoP V [F(3,60)=11.81, d=1.53, p<0.0001; F(3,60)=7.36, d=1.21, p=0.0003] was observed. Statistically significant condition-by-time interactions were found for the balance parameters CoP SA (p<0.003, d=0.54) and CoP V (p<0.002, d=0.70). Specific to contrast analysis, all specified hypotheses were tested and demonstrated that FSSC yielded significantly greater improvements than all other conditions in CoP SA and CoP V [p<0.0001 (d=1.55); p=0.0004 (d=1.19), respectively]. In addition, FSSC yielded significantly greater improvements compared with the two conditions for both balance parameters [p<0.0001 (d=2.03); p<0.0001 (d=1.45)]. Conclusion: Fast stretch-shortening cycle exercises appear to be more effective to improve short-term balance performance in young weightlifters. Due to the importance of balance for overall competitive achievement in weightlifting, it is recommended that young weightlifters implement dynamic plyometric exercises in the fast stretch-shortening cycle during the warm-up to improve their balance performance. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 748 KW - postural stability KW - conditioning exercise KW - adolescents KW - performance KW - weightlifting Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-543109 SN - 1866-8364 ER - TY - GEN A1 - Kuik, Friderike A1 - Lauer, Axel A1 - Churkina, Galina A1 - Denier Van der Gon, Hugo Anne Cornelis A1 - Fenner, Daniel A1 - Mar, Kathleen A. A1 - Butler, Tim M. T1 - Air quality modelling in the Berlin–Brandenburg region using WRF-Chem v3.7.1 BT - sensitivity to resolution of model grid and input data T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Air pollution is the number one environmental cause of premature deaths in Europe. Despite extensive regulations, air pollution remains a challenge, especially in urban areas. For studying summertime air quality in the Berlin-Brandenburg region of Germany, the Weather Research and Forecasting Model with Chemistry (WRF-Chem) is set up and evaluated against meteorological and air quality observations from monitoring stations as well as from a field campaign conducted in 2014. The objective is to assess which resolution and level of detail in the input data is needed for simulating urban background air pollutant concentrations and their spatial distribution in the Berlin-Brandenburg area. The model setup includes three nested domains with horizontal resolutions of 15, 3 and 1 km and anthropogenic emissions from the TNO-MACC III inventory. We use RADM2 chemistry and the MADE/SORGAM aerosol scheme. Three sensitivity simulations are conducted updating input parameters to the single-layer urban canopy model based on structural data for Berlin, specifying land use classes on a sub-grid scale (mosaic option) and downscaling the original emissions to a resolution of ca. 1 km x 1 km for Berlin based on proxy data including traffic density and population density. The results show that the model simulates meteorology well, though urban 2m temperature and urban wind speeds are biased high and nighttime mixing layer height is biased low in the base run with the settings described above. We show that the simulation of urban meteorology can be improved when specifying the input parameters to the urban model, and to a lesser extent when using the mosaic option. On average, ozone is simulated reasonably well, but maximum daily 8 h mean concentrations are underestimated, which is consistent with the results from previous modelling studies using the RADM2 chemical mechanism. Particulate matter is underestimated, which is partly due to an underestimation of secondary organic aerosols. NOx (NO + NO2) concentrations are simulated reasonably well on average, but nighttime concentrations are overestimated due to the model's underestimation of the mixing layer height, and urban daytime concentrations are underestimated. The daytime underestimation is improved when using downscaled, and thus locally higher emissions, suggesting that part of this bias is due to deficiencies in the emission input data and their resolution. The results further demonstrate that a horizontal resolution of 3 km improves the results and spatial representativeness of the model compared to a horizontal resolution of 15 km. With the input data (land use classes, emissions) at the level of detail of the base run of this study, we find that a horizontal resolution of 1 km does not improve the results compared to a resolution of 3 km. However, our results suggest that a 1 km horizontal model resolution could enable a detailed simulation of local pollution patterns in the Berlin-Brandenburg region if the urban land use classes, together with the respective input parameters to the urban canopy model, are specified with a higher level of detail and if urban emissions of higher spatial resolution are used. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 531 KW - urban canopy model KW - aqmeii phase-2 KW - Mexico-City KW - Heat-Island KW - ozone KW - performance KW - transport KW - chemistry KW - meteorology KW - simulation Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-410131 SN - 1866-8372 IS - 531 ER - TY - THES A1 - Brigard Torres, Juan Camilo T1 - An aesthetic cartography of fast T1 - Eine ästhetische Kartographie des aktiven Hungers BT - Gandhi and the hunger artists BT - Gandhis Fasten und die Hungerkünstler*innen N2 - In this cartography, I examine M.K. Gandhi’s practice of fasting for political purposes from a specifically aesthetic perspective. In other words, to foreground their dramatic qualities, how they in their expressive repetition, patterning and stylization produced a/effected heightened forms of emotions. To carry out this task, I follow the theater scholar Erika Fischer-Lichte’s features that give name to her book Äesthetik des Performativen (2004). The cartography is framed in a philosophical presentation of Gandhi’s discourse as well as of his historical sources. Moreover, as a second frame, I historicize the fasts, by means of a typology and teleology in context. The historically and discoursively framed cartography maps four main dimensions that define the aesthetics of the performative: mediality, materiality, semioticity and aestheticity. The first part analyses the medial platforms in which the fasts as events have been historically recorded and in which they have left their traces and inscriptions. These historical sources are namely, newspapers, images, newsreels and a documentary film. Secondly, the material dimension depicts Gandhi’s corporeal condition, as well as the spatiality and temporality of the fasts. In the third place, I revise and reformulate critically Fischer-Lichte’s concepts of “presence” and “representation” with resonating concepts of G. C. Spivak and J. Rancière. This revision illustrates Gandhi’s fasts and shows the process of how an individual may become the embodiment or representation of a national body-politic. The last chapter of the cartography explores the autopoetic-feedback loop between Gandhi and the people and finishes with a comparison of the mise en scène of the hunger artists with the fasts of the Indian the politician, social reformer, and theologian. The text concludes interpreting Gandhi’s practice of fasting under the light of the concepts of “intellectual emancipation” and “de-subjectivation” of the philosopher J. Rancière. The four main concerns of this cartography are: Firstly, in the field of Gandhi’s reception, to explore the aesthetic dimension as both alternative and complementary to the two hegemonic interpretative lenses, i.e. a hagiographic or a secular political understanding of the fasts. From a theoretical perspective, the cartography pursues to be a transdisciplinary experiment that aims at deploying concepts that have been traditionally developed, derived from and used in the field of the arts (theater, film, literature, aesthetic performance, etc.) in the field of the political. In brief, inverting an expression of Rancière, to understand politics as aesthetics. Thirdly, from a thematic point of view, the cartography inquires the historical forms of staging and perception of hunger. Last yet importantly, it is an inquiry of the practice of fasting as nonviolence, what Gandhi, its most sophisticated modern theoretician and practitioner considered its most radical expression. N2 - Die Masterarbeit betrachtet M.K. Gandhis politische Ausübung des Fastens aus einer ästhetischen Perspektive. Im Fokus stehen dabei die dramatischen Eigenschaften dieser asketischen Praxis: Von besonderem Interesse sind expressive Wiederholungen, Gestaltungen und Stilisierungen, die Affekte auslösen. Die Analyse greift auf Begriffe und Theorien von Erika Fischer-Lichtes Ästhetik des Performativen (2004) zurück, um damit die ästhetische Dimension von Gandhis Fasten zu beleuchten. Eine historische und philosophische Kontextualisierung rahmt die ästhetische Kartographie ein. Die Analyse untergliedert sich in vier verschiedene Sphären: Medialität, Materialität, Semiotizität und Ästhetizität. Den Beginn macht eine Untersuchung von medialen Plattformen in den bereits historisierten Spuren der Ereignisse. Als historische Quellen dienen Zeitungsartikel, Fotos, die Wochenschau (newsreel) und ein Dokumentarfilm. Die Sphäre der Materialität wird im Anschluss durch die folgenden Kriterien analysiert: den körperlichen Zustand Gandhis, die Temporalität und die Räumlichkeit des Fastens. Zudem beschäftigt sich der Text mit der Konfiguration von Bedeutung durch eine theoretische Überarbeitung der von Fischer-Lichte geprägten Begriffe von „Präsenz“ und „Repräsentation“. Die Grundlage für diese Überarbeitung sind Texte von J. Rancière und G. C. Spivak. Die Überarbeitung soll mit Beispielen von Gandhis Fasten illustriert werden, um zu zeigen, wie ein individueller Mensch zur Verkörperung oder Repräsentation einer Nation werden kann. Zuletzt nimmt die Analyse der ästhetischen Sphäre die autopoietische Feedback-Schleife zwischen Gandhi und dem Volk in den Blick. Zudem vergleicht die Studie die Inszenierungsformen von Gandhis Fasten und die von den Hungerkünstlern*innen im Westen. Der Abschluss der Masterarbeit verbindet Gandhis Fasten als Ritual mit den von Jacques Rancière entwickelten Begriffen der intellektuellen Emanzipation und der De-Subjektivierung. KW - fasting KW - Gandhi KW - performance KW - aesthetics KW - Hunger KW - Fasten KW - Gandhi KW - Performance KW - Ästhetik KW - hunger Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-469333 ER - TY - THES A1 - Schmidtke, Andrea T1 - Biodiversity effects on the performance of terrestrial plant and phytoplankton communities T1 - Der Effekt der Biodiversität auf die Performance von terrestrischen Pflanzen und Phytoplankton-Gemeinschaften N2 - Die Ökosysteme unserer Erde sind durch das rasante Artensterben infolge von Umweltveränderungen durch den Menschen und des globalen Klimawandels stark betroffen. Mit den Auswirkungen dieses Artenverlustes und der damit einhergehenden Veränderung der Diversität beschäftigt sich die heutige Biodiversitätsforschung. Spezieller wird der Effekt der Diversität auf Ökosystemprozesse wie beispielsweise den Biomasseaufbau von Primärproduzenten oder der Resistenz einer Gemeinschaft gegen die Einwanderung neuer Arten untersucht. Die Quantifizierung des Einflusses der Diversität auf die Primärproduktion und das Verständnis der zugrunde liegenden Mechanismen ist von besonderer Wichtigkeit. In terrestrischen Pflanzengemeinschaften wurde bereits ein positiver Diversitätseffekt auf die Gemeinschaftsbiomasse beobachtet. Dies wird hauptsächlich durch den Komplementaritäts- und/oder den Dominanzeffekt erklärt. Die Komplementarität zwischen Arten ist beispielsweise bei Unterschieden in der Ressourcenausnutzung gegeben (z.B. unterschiedliche Wurzeltiefen). Diese kann zu einer besseren Nährstoffausnutzung in diverseren Gemeinschaften führen, die letztlich deren höhere Biomassen erklärt. Der Dominanzeffekt hingegen beruht auf der in diverseren Gemeinschaften höheren Wahrscheinlichkeit, eine hochproduktive Art anzutreffen, was letztlich die höhere Biomasse der Gemeinschaft verursacht. Diversitätseffekte auf Ökosystemprozesse wurden bisher hauptsächlich auf der Gemeinschaftsebene untersucht. Analysen über die Reaktionen, die alle Arten einer Gemeinschaft einschließen, fehlen bisher. Daher wurde der Einfluss der Diversität auf die individuelle Performance von Pflanzenarten innerhalb des Biodiversitätsprojektes „Das Jena Experiment“ untersucht. Dieses Experiment umfasst 60 Arten, die charakteristisch für Mitteleuropäische Graslandschaften sind. Die Arten wurden in die 4 funktionellen Gruppen Gräser, kleine Kräuter, große Kräuter und Leguminosen eingeteilt. Im Freilandversuch zeigte sich, dass mit steigender Artenzahl die individuelle Pflanzenhöhe zunahm, während die individuelle oberirdische Biomasse sank. Der positive Diversitätseffekt auf die pflanzliche Gemeinschaftsbiomasse kann folglich nicht auf der individuellen oberirdischen Biomassezunahme beruhen. Überdies reagierten die einzelnen funktionellen Gruppen und sogar die einzelnen Arten innerhalb einer funktionellen Gruppe unterschiedlich auf Diversitätsveränderungen. Folglich ist zu vermuten, dass einige Ökosystemprozesse auf Gemeinschaftsebene durch die Reaktionen von bestimmten funktionellen Gruppen bzw. Arten hervorgerufen werden. Diversitätseffekte auf Gemeinschaftsbiomassen wurden bislang hauptsächlich mit terrestrischen Pflanzen und weniger mit frei-schwebenden Algenarten (Phytoplankton) erforscht. Demzufolge wurde der Einfluss der Diversität auf die Biomasse von Phytoplankton-Gemeinschaften experimentell untersucht, wobei es sowohl zu negativen als auch positiven Diversitätseffekten kam. Eine negative Beziehung zwischen Diversität und Gemeinschaftsbiomasse zeigte sich, wenn schnell-wüchsige Algenarten nur geringe Biomassen in Mono- und Mischkultur aufbauten. Die vorhandenen Nährstoffe in der Mischkultur wurden von den schnell-wüchsigen Arten monopolisiert und folglich standen sie den langsam-wüchsigen Algenarten, welche viel Biomasse in Monokultur aufbauten, nicht mehr zur Verfügung. Zu einem positiven Diversitätseffekt auf die Gemeinschaftsbiomasse kam es, wenn die Artengemeinschaft eine positive Beziehung zwischen Wachstumsrate und Biomasse in Monokultur zeigte, sodass die schnell-wüchsige Algenarten viel Biomasse aufbauten. Da diese schnell-wüchsigen Algen in der Mischkultur dominant wurden, bestand die Gemeinschaft letztlich aus hoch-produktiven Algenarten, was zu einer erhöhten Gesamtbiomasse führte. Diese beiden Versuchsansätze verdeutlichen Mechanismen für die unterschiedlichen Reaktionen der Gemeinschaften auf Diversitätsveränderungen, welche auch für terrestrische Pflanzengemeinschaften gefunden wurden. Ein anderer wichtiger Ökosystemprozess, der von der Diversität beeinflusst wird, ist die Anfälligkeit von Gemeinschaften gegenüber invasiven Arten (Invasibilität). Die Invasibilität wird von einer Vielzahl von Faktoren beeinflusst und demzufolge wurde der Effekt der Diversität und der Produktivität (Nährstoffgehalt) auf die Invasibilität von Phytoplankton-Gemeinschaften in An- und Abwesenheit eines Herbivoren untersucht. Die zwei funktionell unterschiedlichen invasiven Arten waren die Blaualge Cylindrospermopsis raciborskii (schlecht fressbar) und der Phytoflagellat Cryptomonas sp. (gut fressbar). Es zeigte sich, dass der Fraßdruck, welcher selber durch die Produktivität beeinflusst wurde, einen bedeutenden Effekt auf die Invasibilität von Phytoplankton-Gemeinschaften hat. Die funktionellen Eigenschaften der invasiven und residenten Arten waren zudem bedeutender als die Artenzahl. N2 - To date, positive relationships between diversity and community biomass have been mainly found, especially in terrestrial ecosystems due to the complementarity and/or dominance effect. In this thesis, the effect of diversity on the performance of terrestrial plant and phytoplankton communities was investigated to get a better understanding of the underlying mechanisms in the biodiversity-ecosystem functioning context. In a large grassland biodiversity experiment, the Jena Experiment, the effect of community diversity on the individual plant performance was investigated for all species. The species pool consisted of 60 plant species belonging to 4 functional groups (grasses, small herbs, tall herbs, legumes). The experiment included 82 large plots which differed in species richness (1-60), functional richness (1-4), and community composition. Individual plant height increased with increasing species richness suggesting stronger competition for light in more diverse communities. The aboveground biomass of the individual plants decreased with increasing species richness indicating stronger competition in more species-rich communities. Moreover, in more species-rich communities plant individuals were less likely to flower out and had fewer inflorescences which may be resulting from a trade-off between resource allocation to vegetative height growth and to reproduction. Responses to changing species richness differed strongly between functional groups and between species of similar functional groups. To conclude, individual plant performance can largely depend on the diversity of the surrounding community. Positive diversity effects on biomass have been mainly found for substrate-bound plant communities. Therefore, the effect of diversity on the community biomass of phytoplankton was studied using microcosms. The communities consisted of 8 algal species belonging to 4 functional groups (green algae, diatoms, cyanobacteria, phytoflagellates) and were grown at different functional richness levels (1-4). Functional richness and community biomass were negatively correlated and all community biomasses were lower than their average monoculture biomasses of the component species, revealing community underyielding. This was mainly caused by the dominance of a fast-growing species which built up low biomasses in monoculture and mixture. A trade-off between biomass and growth rate in monoculture was found for all species, and thus fast-growing species built up low biomasses and slow-growing species reached high biomasses in monoculture. As the fast-growing, low-productive species monopolised nutrients in the mixtures, they became the dominant species resulting in the observed community underyielding. These findings suggest community overyielding when biomasses of the component species are positively correlated with their growth rates in monocultures. Aquatic microcosm experiments with an extensive design were performed to get a broad range of community responses. The phytoplankton communities differed in species diversity (1, 2, 4, 8, and 12), functional diversity (1, 2, 3, and 4) and community composition. The species/functional diversity positively affected community biomass, revealing overyielding in most of the communities. This was mainly caused by a positive complementarity effect which can be attributed to resource use complementarity and/or facilitative interaction among the species. Overyielding of more diverse communities occurred when the biomass of the component species was correlated positively with their growth rates in monoculture and thus, fast-growing and high-productive species were dominant in mixtures. This and the study mentioned above generated an emergent pattern for community overyielding and underyielding from the relationship between biomass and growth rate in monoculture as long as the initial community structure prevailed. Invasive species can largely affect ecosystem processes, whereas invasion is also influenced by diversity. To date, studies revealed negative and positive diversity effects on the invasibility (susceptibility of a community to the invasion by new species). The effect of productivity (nutrient concentration ranging from 10 to 640 µg P L-1), herbivory (presence/absence of the generalist feeder) and diversity (3, 4, 6 species were randomly chosen from the resident species pool) on the invasibility of phytoplankton communities consisting of 10 resident species was investigated using semi-continuous microcosms. Two functionally diverse invaders were chosen: the filamentous and less-edible cynaobacterium C. raciborskii and the unicellular and well-edible phytoflagellate Cryptomonas sp. The phytoflagellate indirectly benefited from grazing pressure of herbivores whereas C. raciborskii suffered more from it. Diversity did not affect the invasibility of the phytoplankton communities. Rather, it was strongly influenced by the functional traits of the resident and invasive species. KW - Artenzahl KW - funktionelle Diversität KW - Ökosystemfunktion KW - Performance KW - Primärproduzenten KW - Species number KW - functional diversity KW - ecosystem functioning KW - performance KW - primary producer Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-38936 ER - TY - JOUR A1 - Sommerer, Thomas A1 - Squatrito, Theresa A1 - Tallberg, Jonas A1 - Lundgren, Magnus T1 - Decision-making in international organizations BT - institutional design and performance JF - The review of international organizations N2 - International organizations (IOs) experience significant variation in their decision-making performance, or the extent to which they produce policy output. While some IOs are efficient decision-making machineries, others are plagued by deadlock. How can such variation be explained? Examining this question, the article makes three central contributions. First, we approach performance by looking at IO decision-making in terms of policy output and introduce an original measure of decision-making performance that captures annual growth rates in IO output. Second, we offer a novel theoretical explanation for decision-making performance. This account highlights the role of institutional design, pointing to how majoritarian decision rules, delegation of authority to supranational institutions, and access for transnational actors (TNAs) interact to affect decision-making. Third, we offer the first comparative assessment of the decision-making performance of IOs. While previous literature addresses single IOs, we explore decision-making across a broad spectrum of 30 IOs from 1980 to 2011. Our analysis indicates that IO decision-making performance varies across and within IOs. We find broad support for our theoretical account, showing the combined effect of institutional design features in shaping decision-making performance. Notably, TNA access has a positive effect on decision-making performance when pooling is greater, and delegation has a positive effect when TNA access is higher. We also find that pooling has an independent, positive effect on decision-making performance. All-in-all, these findings suggest that the institutional design of IOs matters for their decision-making performance, primarily in more complex ways than expected in earlier research. KW - international organizations KW - institutional design KW - decision-making KW - global governance KW - performance Y1 - 2021 U6 - https://doi.org/10.1007/s11558-021-09445-x SN - 1559-7431 SN - 1559-744X VL - 17 IS - 4 SP - 815 EP - 845 PB - Springer CY - Boston ER - TY - JOUR A1 - Islam, Khan M. Shaiful A1 - Schaeublin, H. A1 - Wenk, C. A1 - Wanner, Michael A1 - Liesegang, Annette T1 - Effect of dietary citric acid on the performance and mineral metabolism of broiler JF - Journal of animal physiology and animal nutrition N2 - The objective of this study was to investigate the effect of dietary citric acid (CA) on the performance and mineral metabolism of broiler chicks. A total of 1720 Ross PM3 broiler chicks (days old) were randomly assigned to four groups (430 in each) and reared for a period of 35 days. The diets of groups 1, 2, 3 and 4 were supplemented with 0%, 0.25%, 0.75% or 1.25% CA by weight respectively. Feed and faeces samples were collected weekly and analysed for acid insoluble ash, calcium (Ca), phosphorus (P) and magnesium (Mg). The pH was measured in feed and faeces. At the age of 28 days, 10 birds from each group were slaughtered; tibiae were collected from each bird for the determination of bone mineral density, total ash, Ca, P, Mg and bone-breaking strength, and blood was collected for the measurement of osteocalcin, serum CrossLaps (R), Ca, P, Mg and 1,25(OH)(2)Vit-D in serum. After finishing the trial on day 37, all chicks were slaughtered by using the approved procedure. Birds that were fed CA diets were heavier (average body weights of 2030, 2079 and 2086 g in the 0.25%, 0.75% and 1.25% CA groups, respectively, relative to the control birds (1986 g). Feed conversion efficiency (weight gain in g per kg of feed intake) was also higher in birds of the CA-fed groups (582, 595 and 587 g/kg feed intake for 0.25%, 0.75% and 1.25% CA respectively), relative to the control birds (565 g/kg feed intake). The digestibility of Ca, P and Mg increased in the CA-fed groups, especially for the diets supplemented with 0.25% and 0.75% CA. Support for finding was also indicated in the results of the analysis of the tibia. At slaughter, the birds had higher carcass weights and higher graded carcasses in the groups that were fed the CA diets. The estimated profit margin was highest for birds fed the diet containing 0.25% CA. Birds of the 0.75% CA group were found to have the second highest estimated profit margin. Addition of CA up to a level of 1.25% of the diet increased performance, feed conversion efficiency, carcass weight and carcass quality, but only in numerical terms. The addition of CA up to 0.75% significantly increased the digestibility of macro minerals, bone ash content, bone mineral density and bone strength of the broiler chicks. It may, therefore, be concluded that the addition of 0.75% CA in a standard diet is suitable for growth, carcass traits, macromineral digestibility and bone mineral density of broiler chicks. KW - broiler chicks KW - dietary citric acid KW - calcium KW - phosphorus KW - metabolism KW - performance Y1 - 2012 U6 - https://doi.org/10.1111/j.1439-0396.2011.01225.x SN - 0931-2439 VL - 96 IS - 5 SP - 808 EP - 817 PB - Wiley-Blackwell CY - Hoboken ER -