Altered carbon cycling and trace-metal enrichment during the late Valanginian and early Hauterivian

Abstract.: Carbonates of Valanginian age deposited in the Tethys and Atlantic Oceans show a distinct positive δ13C excursion (Δ δ13C = 1.5‰-2‰) in sections of the neritic, hemipelagic, and pelagic environment. This excursion records a major climate-induced perturbation of the global carbon system. The δ13C excursion is accompanied by enrichments in manganese (Mn) and iron (Fe). The correlation of the δ13C excursion with trends in Mn and Fe contents reflects changes in Valanginian paleoceanography and climate. Fe enrichment occurs mainly in terrestrial, platform, and shelf regions. In a basinal direction the Fe content decreases, whereas the Mn/Fe ratio increases. An increase in sedimentary Mn and Fe concentrations is related to elevated continental weathering rates and to widespread dys- or anoxia that favored metal deposition in Valanginian sediments. Various oceanographic changes (e.g., expansion of oxygen-minimum zones) resulting from increased continental runoff led to a strong remobilization and focused reprecipitation of metals in the oceans of the Valanginian stag

Evaluation of improvements in the separation of monolayer and multilayer films via measurements in transflection and application of machine learning approaches

Small plastic packaging films make up a quarter of all packaging waste generated annually in Austria. As many plastic packaging films are multilayered to give barrier properties and strength, this fraction is considered hardly recyclable and recovered thermally. Besides, they can not be separated from recyclable monolayer films using near-infrared spectroscopy in material recovery facilities. In this paper, an experimental sensor-based sorting setup is used to demonstrate the effect of adapting a near-infrared sorting rig to enable measurement in transflection. This adaptation effectively circumvents problems caused by low material thickness and improves the sorting success when separating monolayer and multilayer film materials. Additionally, machine learning approaches are discussed to separate monolayer and multilayer materials without requiring the near-infrared sorter to explicitly learn the material fingerprint of each possible combination of layered materials. Last, a fast Fourier transform is shown to reduce destructive interference overlaying the spectral information. Through this, it is possible to automatically find the Fourier component at which to place the filter to regain the most spectral information possible

Remodeling of biological tissue: Mechanically induced reorientation of a transversely isotropic chain network

A new class of micromechanically motivated chain network models for soft biological tissues is presented. On the microlevel, it is based on the statistics of long chain molecules. A wormlike chain model is applied to capture the behavior of the collagen microfibrils. On the macrolevel, the network of collagen chains is represented by a transversely isotropic eight chain unit cell introducing one characteristic material axis. Biomechanically induced remodeling is captured by allowing for a continuous reorientation of the predominant unit cell axis driven by a biomechanical stimulus. To this end, we adopt the gradual alignment of the unit cell axis with the direction of maximum principal strain. The evolution of the unit cell axis' orientation is governed by a first-order rate equation. For the temporal discretization of the remodeling rate equation, we suggest an exponential update scheme of Euler-Rodrigues type. For the spatial discretization, a finite element strategy is applied which introduces the current individual cell orientation as an internal variable on the integration point level. Selected model problems are analyzed to illustrate the basic features of the new model. Finally, the presented approach is applied to the biomechanically relevant boundary value problem of an in vitro engineered functional tendon construct.Comment: LaTeX2e, 19 pages, 9 figure

Isolated Langerhans cell histiocytosis of the vulva: a case report and review of the literature

Isolated Langerhans cell histiocytosis (LCH) of the female genital tract is very rare. A review of the literature revealed that only 15 cases of primary vulvar LCH have previously been published in the English literature. We describe an additional case of confined vulvar LCH. A 49-year-old woman presented with an ulcerous lesion that turned out to be LCH confined to the vulva only. After surgical excision, four recurrences followed, which were treated again by surgery. After the fourth recurrence, adjuvant radiotherapy was applied. When the fifth recurrence occurred, only surgical excision was performed, and the patient has now been disease-free for 51months. There are no standard treatment options for this rare disease. The most effective treatment options still remain elusive. In our case in the end surgery proved to be effectiv

Can a “state of the art” chemistry transport model simulate Amazonian tropospheric chemistry?

We present an evaluation of a nested high-resolution Goddard Earth Observing System (GEOS)-Chem chemistry transport model simulation of tropospheric chemistry over tropical South America. The model has been constrained with two isoprene emission inventories: (1) the canopy-scale Model of Emissions of Gases and Aerosols from Nature (MEGAN) and (2) a leaf-scale algorithm coupled to the Lund-Potsdam-Jena General Ecosystem Simulator (LPJ-GUESS) dynamic vegetation model, and the model has been run using two different chemical mechanisms that contain alternative treatments of isoprene photo-oxidation. Large differences of up to 100 Tg C yr^(−1) exist between the isoprene emissions predicted by each inventory, with MEGAN emissions generally higher. Based on our simulations we estimate that tropical South America (30–85°W, 14°N–25°S) contributes about 15–35% of total global isoprene emissions. We have quantified the model sensitivity to changes in isoprene emissions, chemistry, boundary layer mixing, and soil NO_x emissions using ground-based and airborne observations. We find GEOS-Chem has difficulty reproducing several observed chemical species; typically hydroxyl concentrations are underestimated, whilst mixing ratios of isoprene and its oxidation products are overestimated. The magnitude of model formaldehyde (HCHO) columns are most sensitive to the choice of chemical mechanism and isoprene emission inventory. We find GEOS-Chem exhibits a significant positive bias (10–100%) when compared with HCHO columns from the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) and Ozone Monitoring Instrument (OMI) for the study year 2006. Simulations that use the more detailed chemical mechanism and/or lowest isoprene emissions provide the best agreement to the satellite data, since they result in lower-HCHO columns

Stochastische Optimierung im Energiehandel: Entscheidungsunterstützung und Bewertung für das Portfoliomanagement

Unsicherheiten im Strommarkt erfordern flexible Reaktionen von Stromversorgungsunternehmen auf sich kontinuierlich wandelnde Strukturen. Marktteilnehmer ohne marktbeherrschende Stellung müssen zunehmend die kurzfristig hochvolatilen und langfristig nicht prognostizierbaren Preisentwicklungen berücksichtigen. Federführend durch die Stadtwerke Gießen AG und motiviert durch ihre konzeptionellen Herausforderungen im Tagesgeschäft hat das ior/cf-HSG gemeinsam mit der österreichischen Energieberatungsgesellschaft Verbundplan GmbH ein leistungsfähiges Portfoliomanagementsystem auf Basis stochastischer Optimierung entwickelt. Es bietet eine anpassungsfähige Ergänzung zu herkömmlichen Ansätzen und integriert ein innovatives Risikomanagement. Neue Bewertungsansätze für komplexe Derivate reduzieren darüber hinaus das Modellrisiko gegenüber traditionellen Methoden

Swing-Optionen im Elektrizitätsmarkt – Bewertung und optimale Ausübungsstrategien komplexer Stromderivate

Die im Elektrizitätsmarkt als Swing-Optionen bekannten Derivate sind hinsichtlich ihres Charakters und ihrer Einsatzgebiete klassischen Call- und Put-Optionen aus der Finanzwelt ähnlich. So geben Swing-Optionen dem Optionshalter das Recht, während der vereinbarten Ausübungsperiode Energie zu einem vertraglich festgelegten Preis zu kaufen (Call) oder zu verkaufen (Put). Analog den klassischen Finanzoptionen eignen sich Swing-Optionen daher einerseits als Absicherungsinstrumente, andererseits lassen sich spekulative Interessen verfolgen. Die Bewertung von Swing-Optionen erweist sich jedoch als ungleich schwerer, denn oft ist eine solche Option nicht nur durch Rechte, sondern auch durch Verpflichtungen gekennzeichnet. Der hohen Komplexität dieser Derivate kann man mit numerischen Bewertungsmethoden begegnen

Development of 14 microsatellite markers for zoonotic tapeworm dibothriocephalus dendriticus (Cestoda: Diphyllobothriidea)

Dibothriocephalus dendriticus is one of the causative agents of the fish-borne zoonosis diphyllobothriosis. Polymorphic microsatellite markers were originally developed for future genetic studies using microsatellite library screening and next-generation sequencing (NGS). Out of 128 microsatellite candidates selected after NGS analysis, 126 yielded PCR products of the expected size. A declared repetitive motif was confirmed in 92 loci by Sanger sequencing. The level of polymorphism was tested by fragment analysis. Statistical tests for observed and expected heterozygosities and deviations from Hardy–Weinberg equilibrium revealed 14 polymorphic microsatellite loci suitable for studies on the finer genetic structure of global populations of D. dendriticus

Femtosecond Transfer and Manipulation of Persistent Hot-Trion Coherence in a Single CdSe/ZnSe Quantum Dot

Ultrafast transmission changes around the fundamental trion resonance are studied after exciting a p-shell exciton in a negatively charged II-VI quantum dot. The biexcitonic induced absorption reveals quantum beats between hot trion states at 133 GHz. While interband dephasing is dominated by relaxation of the P-shell hole within 390 fs, trionic coherence remains stored in the spin system for 85 ps due to Pauli blocking of the triplet electron. The complex spectro-temporal evolution of transmission is explained analytically by solving the Maxwell-Liouville equations. Pump and probe polarizations provide full control over amplitude and phase of the quantum beats

Low-Latency Scheduling in MPTCP

The demand for mobile communication is continuously increasing, and mobile devices are now the communication device of choice for many people. To guarantee connectivity and performance, mobile devices are typically equipped with multiple interfaces. To this end, exploiting multiple available interfaces is also a crucial aspect of the upcoming 5G standard for reducing costs, easing network management, and providing a good user experience. Multi-path protocols, such as multi-path TCP (MPTCP), can be used to provide performance optimization through load-balancing and resilience to coverage drops and link failures, however, they do not automatically guarantee better performance. For instance, low-latency communication has been proven hard to achieve when a device has network interfaces with asymmetric capacity and delay (e.g., LTE and WLAN). For multi-path communication, the data scheduler is vital to provide low latency, since it decides over which network interface to send individual data segments. In this paper, we focus on the MPTCP scheduler with the goal of providing a good user experience for latency-sensitive applications when interface quality is asymmetric. After an initial assessment of existing scheduling algorithms, we present two novel scheduling techniques: the block estimation (BLEST) scheduler and the shortest transmission time first (STTF) scheduler. BLEST and STTF are compared with existing schedulers in both emulated and real-world environments and are shown to reduce web object transmission times with up to 51% and provide 45% faster communication for interactive applications, compared with MPTCP's default scheduler