Active Cancellation of Tollmien-Schlichting Waves under Varying Inflow Conditions for In-Flight Application

Active flow control in laminar boundary layers can reduce wall friction on a wing, if laminar-turbulent transition is delayed. In this thesis, (re-)active flow control for active cancellation of Tollmien-Schlichting (TS) waves in a two-dimensional laminar boundary layer is investigated. The TS-waves that initiate the transition to turbulence are attenuated with a DBD plasma actuator by superposition. Active wave cancelation requires the use of control algorithms and their stability is influenced by variable inflow conditions. Model-based (Linear-Quadratic-Gaussian) and adaptive control algorithms (filtered-x-LMS) are investigated under realistic (varying) inflow conditions in wind-tunnel and in-flight experiments. The further developed delayed-x-LMS algorithm allows a stable and robust controller operation for active wave cancelation in flight. All experimental results are validated by direct numerical simulations and linear stability theory. Furthermore, the challenges for the application of DBD plasma actuator arrays to delay natural transition are pointed out. The simplification of transfer paths for reducing the required computational power is discussed

Funktionssicherheit integrierter Laufhöfe gemäß EG-Öko-VO in der Milchviehhaltung

Beim Bau von Außenklimaställen steht das Tierwohl im Vordergrund. Nicht überdachte Laufhöfe gemäß EG-Öko-VO sind zwischenzeitlich fester Bestandteil zukunftsfähiger Stallanlagen. Diese geben den Tieren die Möglichkeit, sich dem direkten Außenklimareiz auszusetzen. Bei einhäusigen Stallanlagen werden Laufhöfe außerhalb, bei mehrhäusigen zwischen den Teilbaukörpern angeordnet. Diese integrierten Laufhöfe weisen Vorteile (u. a. verringerter Investitionsbedarf) auf. Je nach Geometrie und Anordnung der Teilbaukörper kann es aber zum vermehrten Eintrag von Schnee in den Laufhof und unerwünschtem Schlagregen in angrenzende Funktionsbereiche kommen. Bei den untersuchten Varianten für mehrhäusige Stallmodelle zeigen flache Dachneigungen mit großen Vordächern die geringsten Niederschlagseinträge

Funktionssicherheit integrierter Laufhöfe gem. EG-Öko-VO

Gem. Verordnung (EG) Nr. 834/ 2007 (EG-Öko-VO) ist für Milchkühe in ganzjähriger Stallhaltung eine (anteilig) nicht überdachte Auslauffläche gefordert. Ausläufe innerhalb mehrhäusiger Stallanlagen zeigen viele Vorteile (Funktion, Investitionsbedarf), können aber zu Niederschlagseintrag in angrenzende Funktionsbereiche führen. Ziel des Projektes ist es, für diese Fragestellung über gebaute Praxisbeispiele und Stallmodelle im Windkanal Lösungen zu entwickeln. Aus den ersten Messreihen zeigen dabei flach geneigte Dächer (≤ 9°) deutliche Vorteile gegenüber steiler geneigten Dächern

Stärkung der Wettbewerbsfähigkeit der ökologischen Ferkelerzeugung in Bayern - ein interdisziplinäres Projekt

Die Wettbewerbsfähigkeit der für Süddeutschland typischen, bäuerlichen Ferkelerzeugung ist im ökologischen Landbau bisher gering. Dadurch besteht ein Umstellungshemmnis, das die weitere Entwicklung der Schweinhaltung im Ökolandbau behindert. Das vorgestellte interdisziplinäre Projekt soll mithilfe einer engen Zusammenarbeit von Forschung, Beratung und Praxis einen wesentlichen Beitrag zur Verbesserung der Produktionsbedingungen liefern. Ziel ist es, Grundlagen für eine Erhöhung von Leistung und Wertschöpfung in der ökologischen Ferkelerzeugung zu erarbeiten. Dies geschieht durch eine Verbesserung des Stands des Wissens über geeignete Haltungsverfahren, Stallbaulösungen, Arbeitsorganisation, Prozessqualität und Betriebswirtschaft. An dem Projekt sind sieben Arbeitsgruppen und elf Praxisbetriebe beteiligt. Das Projekt startete im Juli 2008 und wird voraussichtlich Ende 2010 abgeschlossen werden

Increased zinc accumulation in mineralized osteosarcoma tissue measured by confocal synchrotron radiation micro X-ray fluorescence analysis

Abnormal tissue levels of certain trace elements such as zinc (Zn) were reported in various types of cancer. Little is known about the role of Zn in osteosarcoma. Using confocal synchrotron radiation micro X-ray fluorescence analysis, we characterized the spatial distribution of Zn in high-grade sclerosing osteosarcoma of nine patients (four women/five men; seven knee/one humerus/one femur) following chemotherapy and wide surgical resection. Levels were compared with adjacent normal tissue. Quantitative backscattered electron imaging as well as histological examinations was also performed. On average, the ratio of medians of Zn count rates (normalized to calcium) in mineralized tumor tissue was about six times higher than in normal tissue. There was no difference in Zn levels between tumor fraction areas with a low fraction and a high fraction of mineralized tissue, which were clearly depicted using quantitative backscattered electron imaging. Moreover, we found no correlation between the Zn values and the type of tumor regression according to the Salzer-Kuntschik grading. The underlying mechanism of Zn accumulation remains unclear. Given the emerging data on the role of trace elements in other types of cancer, our novel results warrant further studies on the role of trace elements in bone cancer

Climate change impacts and adaptation in Europe

The JRC PESETA IV study shows that ecosystems, people and economies in the EU will face major impacts from climate change if we do not urgently mitigate greenhouse gas emissions or adapt to climate change. The burden of climate change shows a clear north-south divide, with southern regions in Europe much more impacted, through the effects of extreme heat, water scarcity, drought, forest fires and agriculture losses. Limiting global warming to well below 2°C would considerably reduce climate change impacts in Europe. Adaptation to climate change would further minimize unavoidable impacts in a cost-effective manner, with considerable co-benefits from nature-based solutions.JRC.C.6-Economics of Climate Change, Energy and Transpor

Identification of heavy-flavour jets with the CMS detector in pp collisions at 13 TeV

Many measurements and searches for physics beyond the standard model at the LHC rely on the efficient identification of heavy-flavour jets, i.e. jets originating from bottom or charm quarks. In this paper, the discriminating variables and the algorithms used for heavy-flavour jet identification during the first years of operation of the CMS experiment in proton-proton collisions at a centre-of-mass energy of 13 TeV, are presented. Heavy-flavour jet identification algorithms have been improved compared to those used previously at centre-of-mass energies of 7 and 8 TeV. For jets with transverse momenta in the range expected in simulated $\mathrm{t}\overline{\mathrm{t}}$ events, these new developments result in an efficiency of 68% for the correct identification of a b jet for a probability of 1% of misidentifying a light-flavour jet. The improvement in relative efficiency at this misidentification probability is about 15%, compared to previous CMS algorithms. In addition, for the first time algorithms have been developed to identify jets containing two b hadrons in Lorentz-boosted event topologies, as well as to tag c jets. The large data sample recorded in 2016 at a centre-of-mass energy of 13 TeV has also allowed the development of new methods to measure the efficiency and misidentification probability of heavy-flavour jet identification algorithms. The heavy-flavour jet identification efficiency is measured with a precision of a few per cent at moderate jet transverse momenta (between 30 and 300 GeV) and about 5% at the highest jet transverse momenta (between 500 and 1000 GeV)

Evenness mediates the global relationship between forest productivity and richness

1. Biodiversity is an important component of natural ecosystems, with higher species richness often correlating with an increase in ecosystem productivity. Yet, this relationship varies substantially across environments, typically becoming less pronounced at high levels of species richness. However, species richness alone cannot reflect all important properties of a community, including community evenness, which may mediate the relationship between biodiversity and productivity. If the evenness of a community correlates negatively with richness across forests globally, then a greater number of species may not always increase overall diversity and productivity of the system. Theoretical work and local empirical studies have shown that the effect of evenness on ecosystem functioning may be especially strong at high richness levels, yet the consistency of this remains untested at a global scale. 2. Here, we used a dataset of forests from across the globe, which includes composition, biomass accumulation and net primary productivity, to explore whether productivity correlates with community evenness and richness in a way that evenness appears to buffer the effect of richness. Specifically, we evaluated whether low levels of evenness in speciose communities correlate with the attenuation of the richness–productivity relationship. 3. We found that tree species richness and evenness are negatively correlated across forests globally, with highly speciose forests typically comprising a few dominant and many rare species. Furthermore, we found that the correlation between diversity and productivity changes with evenness: at low richness, uneven communities are more productive, while at high richness, even communities are more productive. 4. Synthesis. Collectively, these results demonstrate that evenness is an integral component of the relationship between biodiversity and productivity, and that the attenuating effect of richness on forest productivity might be partly explained by low evenness in speciose communities. Productivity generally increases with species richness, until reduced evenness limits the overall increases in community diversity. Our research suggests that evenness is a fundamental component of biodiversity–ecosystem function relationships, and is of critical importance for guiding conservation and sustainable ecosystem management decisions

Reproducibility in the absence of selective reporting: An illustration from large‐scale brain asymmetry research

The problem of poor reproducibility of scientific findings has received much attention over recent years, in a variety of fields including psychology and neuroscience. The problem has been partly attributed to publication bias and unwanted practices such as p‐hacking. Low statistical power in individual studies is also understood to be an important factor. In a recent multisite collaborative study, we mapped brain anatomical left–right asymmetries for regional measures of surface area and cortical thickness, in 99 MRI datasets from around the world, for a total of over 17,000 participants. In the present study, we revisited these hemispheric effects from the perspective of reproducibility. Within each dataset, we considered that an effect had been reproduced when it matched the meta‐analytic effect from the 98 other datasets, in terms of effect direction and significance threshold. In this sense, the results within each dataset were viewed as coming from separate studies in an “ideal publishing environment,” that is, free from selective reporting and p hacking. We found an average reproducibility rate of 63.2% (SD = 22.9%, min = 22.2%, max = 97.0%). As expected, reproducibility was higher for larger effects and in larger datasets. Reproducibility was not obviously related to the age of participants, scanner field strength, FreeSurfer software version, cortical regional measurement reliability, or regional size. These findings constitute an empirical illustration of reproducibility in the absence of publication bias or p hacking, when assessing realistic biological effects in heterogeneous neuroscience data, and given typically‐used sample sizes

Evenness mediates the global relationship between forest productivity and richness

1. Biodiversity is an important component of natural ecosystems, with higher species richness often correlating with an increase in ecosystem productivity. Yet, this relationship varies substantially across environments, typically becoming less pronounced at high levels of species richness. However, species richness alone cannot reflect all important properties of a community, including community evenness, which may mediate the relationship between biodiversity and productivity. If the evenness of a community correlates negatively with richness across forests globally, then a greater number of species may not always increase overall diversity and productivity of the system. Theoretical work and local empirical studies have shown that the effect of evenness on ecosystem functioning may be especially strong at high richness levels, yet the consistency of this remains untested at a global scale. 2. Here, we used a dataset of forests from across the globe, which includes composition, biomass accumulation and net primary productivity, to explore whether productivity correlates with community evenness and richness in a way that evenness appears to buffer the effect of richness. Specifically, we evaluated whether low levels of evenness in speciose communities correlate with the attenuation of the richness–productivity relationship. 3. We found that tree species richness and evenness are negatively correlated across forests globally, with highly speciose forests typically comprising a few dominant and many rare species. Furthermore, we found that the correlation between diversity and productivity changes with evenness: at low richness, uneven communities are more productive, while at high richness, even communities are more productive. 4. Synthesis. Collectively, these results demonstrate that evenness is an integral component of the relationship between biodiversity and productivity, and that the attenuating effect of richness on forest productivity might be partly explained by low evenness in speciose communities. Productivity generally increases with species richness, until reduced evenness limits the overall increases in community diversity. Our research suggests that evenness is a fundamental component of biodiversity–ecosystem function relationships, and is of critical importance for guiding conservation and sustainable ecosystem management decisions