Anisotropy of third-order structure functions in MHD turbulence

The measure of the third-order structure function, Y, is employed in the solar wind to compute the cascade rate of turbulence. In the absence of a mean field B0=0, Y is expected to be isotropic (radial) and independent of the direction of increments, so its measure yields directly the cascade rate. For turbulence with mean field, as in the solar wind, Y is expected to become more two dimensional (2D), that is, to have larger perpendicular components, loosing the above simple symmetry. To get the cascade rate one should compute the flux of Y, which is not feasible with single-spacecraft data, thus measurements rely upon assumptions about the unknown symmetry. We use direct numerical simulations (DNS) of magneto-hydrodynamic (MHD) turbulence to characterize the anisotropy of Y. We find that for strong guide field B0=5 the degree of two-dimensionalization depends on the relative importance of shear and pseudo polarizations (the two components of an Alfv\'en mode in incompressible MHD). The anisotropy also shows up in the inertial range. The more Y is 2D, the more the inertial range extent differs along parallel and perpendicular directions. We finally test the two methods employed in observations and find that the so-obtained cascade rate may depend on the angle between B0 and the direction of increments. Both methods yield a vanishing cascade rate along the parallel direction, contrary to observations, suggesting a weaker anisotropy of solar wind turbulence compared to our DNS. This could be due to a weaker mean field and/or to solar wind expansion.Comment: Some text editing and typos corrected, 13 pages, 6 figures, to be published in Ap

Improving Surgical Training Phantoms by Hyperrealism: Deep Unpaired Image-to-Image Translation from Real Surgeries

Current `dry lab' surgical phantom simulators are a valuable tool for surgeons which allows them to improve their dexterity and skill with surgical instruments. These phantoms mimic the haptic and shape of organs of interest, but lack a realistic visual appearance. In this work, we present an innovative application in which representations learned from real intraoperative endoscopic sequences are transferred to a surgical phantom scenario. The term hyperrealism is introduced in this field, which we regard as a novel subform of surgical augmented reality for approaches that involve real-time object transfigurations. For related tasks in the computer vision community, unpaired cycle-consistent Generative Adversarial Networks (GANs) have shown excellent results on still RGB images. Though, application of this approach to continuous video frames can result in flickering, which turned out to be especially prominent for this application. Therefore, we propose an extension of cycle-consistent GANs, named tempCycleGAN, to improve temporal consistency.The novel method is evaluated on captures of a silicone phantom for training endoscopic reconstructive mitral valve procedures. Synthesized videos show highly realistic results with regard to 1) replacement of the silicone appearance of the phantom valve by intraoperative tissue texture, while 2) explicitly keeping crucial features in the scene, such as instruments, sutures and prostheses. Compared to the original CycleGAN approach, tempCycleGAN efficiently removes flickering between frames. The overall approach is expected to change the future design of surgical training simulators since the generated sequences clearly demonstrate the feasibility to enable a considerably more realistic training experience for minimally-invasive procedures.Comment: 8 pages, accepted at MICCAI 2018, supplemental material at https://youtu.be/qugAYpK-Z4

Züchterische Weiterentwicklung samenfester Brokkolisorten für den Ökologischen Landbau im Hinblick auf agronomische Merkmale, sekundäre, bioaktive Inhaltsstoffe und sensorische Eigenschaften

Ziel des Projektes war, Zuchtpopulationen bzw. traditionelle, offen blühende Brokkoli-Sorten (keine Hybriden bzw. CMS-Hybriden) speziell für den Ökologischen Landbau zu prüfen. Wichtige Eigenschaften waren dabei Ertragssicherheit, Einheitlichkeit, enges Erntefenster, Festigkeit der Blume sowie hohe Gehalte an sekundären, bioaktiven Inhaltsstoffen, insbesondere von Glucosinolaten. Um eine schnelle und kostengünstige Möglichkeit zum Screening von bioaktiven Inhaltsstoffen zu entwickeln, die für den On-Farm-Einsatz geeignet ist, wurde zudem ein zerstörungsfrei arbeitendes Sensortool getestet. Während der dreijährigen Projektlaufzeit erfolgten On-Farm-Selektionen geeigneter Brokkolilinien/-sorten auf Kultursaat-Zuchtstandorten sowie auf der Versuchsstation für Ökologischen Landbau Kleinhohenheim, Universität Hohenheim. Die Ergebnisse des Projektes zeigten, dass bei großer Variabilität unter den Genotypen einige bereits vielversprechende agronomische Eigenschaften (Blumengewicht, Aberntegrad, Ertrag, Blumendurchmesser) aufwiesen, die nur leicht unter denen der untersuchten Hybriden lagen. Die Glucosinolatgehalte waren signifikant abhängig von Genotyp und Anbauzeitraum, wobei die samenfesten Genotypen und Sorten tendenziell höhere Glucosinolatgehalte zeigten als die Hybridsorten. Im Projektverlauf konnte beim Vergleich der Mutterlinien mit den züchterisch bearbeiteten Genotypen ein Zuchtfortschritt zu höheren Glucosinolatgehalten festgestellt werden. Für Einzelglucosinolate konnte eine Kalibierung des Sensortools erfolgreich durchgeführt werden, wobei der Beginn der Blumenentwicklung sich als Zeitpunkt für erste Messungen als günstig erwies. Der Einsatz des Sensortools im Blattstadium war jedoch nicht möglich. Bei den Verkostungen durch hedonische und analytische Panels wurden zwei samenfeste Genotypen und eine Hybride als besonders schmackhaft bewertet. Schlussendlich konnten zwei samenfeste Genotypen identifiziert werden, die in allen Eigenschaften (agronomisch, Glucosinolatgehalte, Geschmack) gut bis sehr gut bewertet wurden und daher für die weitere Sortenentwicklung geeignet sind

Messung sekundärer Pflanzeninhaltsstoffe von Brokkoliblumen aus ökologischem Anbau

Today, consumer awareness on the healthiness of their foodstuff increases. The main focus is on secondary metabolites and antioxidants. Broccoli (Brassica oleracea L. convar. botrytis Alef. var. italica Plenck) has many compounds beneficial for human health, like Vitamin C, Carotionoids or Anthocyanins. To investigate these compounds two techniques are used in this study which are non-destructive sensor measurements (Multiplex®) to determine the value of anthocyanins (ANTH_RG) and flavonols (FLAV) and measurements of the antioxidant potential (water- (ACW) and lipid- (ACL) soluble antioxidants) on the basis of chemoluminescence. Field trials in autumn of 2011 and spring of 2012 were conducted in a randomized block design with different broccoli genotypes, named “Limba”, “Marathon F1” and “TH-CAN-FK”. Measurements were done two times in 2011 and three times in 2012 on broccoli florets. Results indicate that the effect of the sampling date had a significant effect on FLAV, ANTH_RG, ACL and ACW values in Broccoli florets, while the effect of the genotype had only an influence on the ANTH_RG value. These effects may be due to less rainfall and pest infestations

Open Pollinated Broccoli Genotypes: Agronomic Parameters and Sensory Attributes

Breeding of open pollinated (OP) varieties for organic farming gains further importance as varieties created by breeding techniques like CMS-hybridisation and cell fusion are no longer accepted by several organic farming associations. For broccoli (Brassica oleracea var. italica), the availability of OP varieties is very limited and the ones available are often not suitable for commercial crop production. In a participatory breeding project of the non-governmental, non-profit German association Kultursaat e.V. and the University of Hohenheim new genotypes were tested for agronomic parameters in field trials and sensory traits of cooked and raw broccoli were evaluated by two untrained consumer panels in 2012 and 2013. Agronomic traits of hybrids and OP genotypes varied widely, e.g. one OP genotype showed similar head weights (380 g) and head diameters (18 cm) as the standard hybrid (340 g and 17 cm), while other OP genotypes were often much lower in weight (240 g) and head diameter (13 cm). In addition, some of the OP genotypes were very heterogeneous in colour ranging from green to violet. In the sensory assessment of the varieties, untrained consumers were able to differentiate between the different genotypes. The ranking for the genotypes differed when eaten cooked or raw. Positively associated taste attributes for broccoli were “nutty”, “cabbage-like”, “sweet” and “spicy” for cooked samples, in raw samples “spicy” was evaluated negatively. Other negatively associated attributes were “bitter” and “off-flavour” for both raw and cooked material. On an overall level the OP genotype CHE-MIC showed the highest acceptance amongst consumers for cooked broccoli in 2012 and 2013. Out of the OP genotypes CHE-MIC has the potential to be commercially successful in particular after further selection for homogeneity for example in colour and head diameter has taken place

Second harmonic generation from strongly coupled localized and propagating phonon-polariton modes

We experimentally investigate second harmonic generation from strongly coupled localized and propagative phonon polariton modes in arrays of silicon carbide nanopillars. Our results clearly demonstrate the hybrid nature of the system's eigenmodes and distinct manifestation of strong coupling in the linear and nonlinear response. While in linear reflectivity the intensity of the two strongly-coupled branches is essentially symmetric and well explained by their respective localized or propagative components, the second harmonic signal presents a strong asymmetry. Analyzing it in detail, we reveal the importance of interference effects between the nonlinear polarization terms originating in the bulk and in the phonon polariton modes, respectively.Comment: 7 pages, 4 figure

Crossbred Sows Fed a Western Diet during Pre-Gestation, Gestation, Lactation, and Post-Lactation Periods Develop Signs of Lean Metabolic Syndrome That Are Partially Attenuated by Spirulina Supplementation.

Excessive dietary intake of fats and sugars ("Western diet", WD) is one of the leading causes of obesity. The consumption of the microalga Arthrospira platensis (spirulina, Sp) is increasing due to its presumed health benefits. Both WD and Sp are also consumed by pregnant and breastfeeding women. This study investigated if gestating and lactating domestic pigs are an appropriate model for WD-induced metabolic disturbances similar to those observed in humans and if Sp supplementation may attenuate any of these adverse effects. Pigs were fed a WD high in fat, sugars, and cholesterol or a control diet. Half of the animals per diet group were supplemented with 20 g Sp per day. The WD did not increase body weight or adipose tissue accumulation but led to metabolic impairments such as higher cholesterol concentration in plasma, lower IGF1 plasma levels, and signs of hepatic damage compared to the control group. Spirulina supplementation could not reduce all the metabolic impairments observed in WD-fed animals. These findings indicate limited suitability of gestating and lactating domestic pigs as a model for WD but a certain potential of low-dose Sp supplementation to partially attenuate negative WD effects