384 research outputs found
Apfeltrester im Schweinefutter reduziert die durch das Mykotoxin Deoxynivalenol verursachte Wachtumsreduktion
Fusarium head blight and the contamination of cereals with the Fusarium toxins deoxynivalenol (DON) and zearalenone is more prevalent when fields are not tilled in order to conserve the soil structure. DON impairs the feed intake and the growth rate of young pigs, whereas both, DON and zearalenone affect the fertility of sows. In two feeding trials using a total of 220 weaner pigs the hypothesis was tested that apple pomace alleviates the negative effects of Fusarium toxins. The two experiments had a 2 x 2 factorial design: Fusarium contaminated and uncontaminated wheat, and 8 % apple pomace and no pomace in the diet. In both trials, the animals receiving the mycotoxin contaminated diets without pomace gained less weight than the pigs receiving either uncontaminated diets without pomace (p = 0.03 and = 0.11) or contaminated diets with pomace (p = 0.07 and = 0.03). In the second trial, female piglets receiving the contaminated diets which contained zearalenone as well as DON had heavier uteri than those on uncontaminated diets (p = 0.003), regardless of apple pomace supplementation. In conclusion, apple pomace may be used to counteract the negative effects of DON on growth, but is ineffective against the oestrogenic effects of zearalenone
Reduced clonal reproduction indicates low potential for establishment of hybrids between wild and cultivated strawberries ( Fragaria vesca × F. × ananassa )
The genus Fragaria (Rosaceae) contains 24 species, including hybrid species such as the garden strawberry (Fragaria×ananassa Duch.). Natural hybridization between Fragaria species has repeatedly been reported, and studies on the hybridization potential between F.×ananassa and its wild relatives have become increasingly important with the outlook for genetically modified garden strawberries. In Europe, a candidate species for hybridization with garden strawberries is the common woodland strawberry (Fragaria vesca L.). Although a previous field survey indicated that the potential for hybridization between F. vesca and F.×ananassa is low, it is not clear whether the lack of natural hybrids is caused by known pre- and postzygotic barriers, or whether hybrid plants lack the fitness to establish in natural F. vesca populations. We grew different F. vesca and F. vesca×F.×ananassa hybrid clones with and without competition in a greenhouse and assessed biomass production, clonal reproduction, and sexual reproduction of plants. While some hybrid clones exceeded F. vesca in biomass production, general clonal reproduction was much lower and delayed in hybrids. Furthermore, hybrids were sterile. These results demonstrate a mechanism by which the general lack of F. vesca×F.×ananassa hybrids in natural habitats can be explained, in addition to the known low hybridization potential between garden and woodland strawberries. We conclude that hybrids have a competitive disadvantage against co-occurring F. vesca plants due to inferior and delayed clonal reproduction, and that the potential for hybrid establishment under natural conditions is lo
Performance limits of astronomical arrayed waveguide gratings on silica platform
We present a numerical and experimental study of the impact of phase errors
on the performance of large, high-resolution Arrayed Waveguide Gratings (AWG)
for applications in astronomy. We use a scalar diffraction model to study the
transmission spectrum of an AWG under random variations of the optical
waveguide lengths. We simulate phase error correction by numerically trimming
the lengths of the optical waveguides to the nearest integer multiple of the
central wavelength. The optical length error distribution of a
custom-fabricated silica AWG is measured using frequency-domain interferometry
and Monte-Carlo fitting of interferogram intensities. In the end, we give an
estimate for the phase-error limited size of a waveguide array manufactured
using state-of-the-art technology. We show that post-processing eliminates
phase errors as a performance limiting factor for astronomical spectroscopy in
the H-band.Comment: 14 pages, 13 figures; to be published in Optics Expres
From Prediction to Planning With Goal Conditioned Lane Graph Traversals
The field of motion prediction for automated driving has seen tremendous
progress recently, bearing ever-more mighty neural network architectures.
Leveraging these powerful models bears great potential for the closely related
planning task. In this letter we propose a novel goal-conditioning method and
show its potential to transform a state-of-the-art prediction model into a
goal-directed planner. Our key insight is that conditioning prediction on a
navigation goal at the behaviour level outperforms other widely adopted
methods, with the additional benefit of increased model interpretability. We
train our model on a large open-source dataset and show promising performance
in a comprehensive benchmark
Ein regionaler Arbeitsmarkt im Umbruch : wirtschaftliche Situation und Beschäftigung im Kreis Pirna (Sachsen) beim Übergang zur Marktwirtschaft
"Im Sommer 1990 führte eine Arbeitsgruppe des Zentralen Forschungsinstituts für Arbeit, Dresden (ZFA) eine regionale Analyse zur wirtschaftlichen Situation und zur Arbeitsmarktlage im Kreis Pirna durch. Die Auswertung verschiedener statistischer Materialien zur Beschäftigungsstruktur, zum Ausbildungsstellenmarkt sowie eine Betriebsbefragung bildeten die Basis, den Umstrukturierungsprozeß ansatzweise transparent zu machen. Schwerpunkte der Analyse lagen in der Darstellung der Qualifikationsstruktur des Erwerbstätigenpotentials und der Strukturierung der Arbeitslosigkeit im Juli 1990. Die genutzten arbeitsmarktpolitischen Instrumente - FuU, ABM und Kurzarbeit - werden zusammenfassend abgebildet. Einen weiteren Schwerpunkt bildet die Ableitung und Interpretation der Tendenzen des regionalen Arbeitsmarktes im Kontext der wirtschaftlichen Entwicklung. Es wird deutlich, daß auch weiterhin Arbeitsplätze abgebaut werden; diese werden weder quantitativ noch qualitativ durch neugeschaffene Arbeitsplätze kompensiert." (Autorenreferat)regionaler Arbeitsmarkt, Erwerbspersonenpotenzial, Qualifikationsstruktur, Beschäftigtenstruktur, Ausbildungsstellenmarkt, Arbeitslosigkeit, Wirtschaftszweige, Wirtschaftssystem - Reform, Arbeitsmarktpolitik, Pirna, DDR, Sachsen
Searching for gene flow from cultivated to wild strawberries in Central Europe
Background and Aims Experimental crosses between the diploid woodland strawberry (Fragaria vesca L.) and the octoploid garden strawberry (F. × ananassa Duch.) can lead to the formation of viable hybrids. However, the extent of such hybrid formation under natural conditions is unknown, but is of fundamental interest and importance in the light of the potential future cultivation of transgenic strawberries. A hybrid survey was therefore conducted in the surroundings of ten farms in Switzerland and southern Germany, where strawberries have been cultivated for at least 10 years and where wild strawberries occur in the close vicinity. Methods In 2007 and 2008, 370 wild F. vesca plants were sampled at natural populations around farms and analysed with microsatellite markers. In 2010, natural populations were revisited and morphological traits of 3050 F. vesca plants were inspected. DNA contents of cell nuclei of morphologically deviating plants were estimated by flow cytometry to identify hybrids. As controls, 50 hybrid plants from interspecific hand-crosses were analysed using microsatellite analysis and DNA contents of cell nuclei were estimated by flow cytometry. Key Results None of the wild samples collected in 2007 and 2008 contained F. × ananassa microsatellite markers, while all hybrids from hand-crosses clearly contained markers of both parent species. Morphological inspection of wild populations carried out in 2010 and subsequent flow cytometry of ten morphologically deviating plants revealed no hybrids. Conclusions Hybrid formation or hybrid establishment in natural populations in the survey area is at best a rare even
The relative importance of sexual and clonal reproduction for population growth in the perennial herb Fragaria vesca
The relative importance of sexual and clonal reproduction for population growth in clonal plants is highly variable. Clonal reproduction is often more important than sexual reproduction but there is considerable interspecific variation and the importance of the two reproductive modes can change with environmental conditions. We carried out a demographic study on the woodland strawberry (Fragaria vesca), a widespread clonal herb, at 12 sites in Switzerland during 2years. Study sites were selected in two different habitats, i.e., forest and forest edge. We used periodic matrix models to estimate annual population growth rates and carried out prospective analyses to identify life cycle components that influence population growth rates most. Retrospective analyses were applied to study how the two different habitats affected population dynamics. Furthermore, we tested whether trade-offs between sexual and clonal reproduction occurred. There were large differences in annual population growth rates between sites and large within-site differences between years. Results of the prospective analyses clearly indicate that clonal reproduction is the dominant reproductive pathway whereas sexual reproduction is rather insignificant for population growth. Compared to forest habitats, forest edge habitats had higher population growth rates in the first year but smaller growth rates in the second year. We attribute these differing habitat effects to different water availabilities during consecutive years. No trade-offs between sexual and clonal reproduction were found. In conclusion, population growth of F. vesca relies heavily on clonal reproduction. Furthermore, reproduction and survival rates of F. vesca depend highly on spatio-temporal variation of environmental condition
Uncertainty Propagation of Initial Conditions in Thermal Models
The operation of machine tools often demands a highly accurate knowledge of
the tool center point's (TCP) position. The displacement of the TCP over time
can be inferred from thermal models, which comprise a set of geometrically
coupled heat equations. Each of these equations represents the temperature in
part of the machine, and they are often formulated on complicated geometries.
The accuracy of the TCP prediction depends highly on the accuracy of the
model parameters, such as heat exchange parameters, and the initial
temperature. Thus it is of utmost interest to determine the influence of these
parameters on the TCP displacement prediction. In turn, the accuracy of the
parameter estimate is essentially determined by the measurement accuracy and
the sensor placement.
Determining the accuracy of a given sensor configuration is a key
prerequisite of optimal sensor placement. We develop here a thermal model for a
particular machine tool. On top of this model we propose two numerical
algorithms to evaluate any given thermal sensor configuration with respect to
its accuracy. We compute the posterior variances from the posterior covariance
matrix with respect to an uncertain initial temperature field. The full matrix
is dense and potentially very large, depending on the model size. Thus, we
apply a low-rank method to approximate relevant entries, i.e. the variances on
its diagonal. We first present a straightforward way to compute this
approximation which requires computation of the model sensitivities with with
respect to the initial values. Additionally, we present a low-rank tensor
method which exploits the underlying system structure. We compare the
efficiency of both algorithms with respect to runtime and memory requirements
and discuss their respective advantages with regard to optimal sensor placement
problems
Stay on Track: A Frenet Wrapper to Overcome Off-road Trajectories in Vehicle Motion Prediction
Predicting the future motion of observed vehicles is a crucial enabler for
safe autonomous driving. The field of motion prediction has seen large progress
recently with State-of-the-Art (SotA) models achieving impressive results on
large-scale public benchmarks. However, recent work revealed that
learning-based methods are prone to predict off-road trajectories in
challenging scenarios. These can be created by perturbing existing scenarios
with additional turns in front of the target vehicle while the motion history
is left unchanged. We argue that this indicates that SotA models do not
consider the map information sufficiently and demonstrate how this can be
solved, by representing model inputs and outputs in a Frenet frame defined by
lane centreline sequences. To this end, we present a general wrapper that
leverages a Frenet representation of the scene and that can be applied to SotA
models without changing their architecture. We demonstrate the effectiveness of
this approach in a comprehensive benchmark using two SotA motion prediction
models. Our experiments show that this reduces the off-road rate on challenging
scenarios by more than 90\%, without sacrificing average performance
Design, simulation and characterization of integrated photonic spectrographs for astronomy: generation-I AWG devices based on canonical layouts
We present an experimental study on our first generation of custom-developed arrayed waveguide gratings (AWG) on a silica platform for spectroscopic applications in near-infrared astronomy. We provide a comprehensive description of the design, numerical simulation and characterization of several AWG devices aimed at spectral resolving powers of 15,000-60,000 in the astronomical H-band. We evaluate the spectral characteristics of the fabricated devices in terms of insertion loss and estimated spectral resolving power and compare the results with numerical simulations. We estimate resolving powers of up to 18,900 from the output channel 3-dB transmission bandwidth. Based on the first characterization results, we select two candidate AWGs for further processing by removal of the output waveguide array and polishing the output facet to optical quality with the goal of integration as the primary diffractive element in a cross-dispersed spectrograph. We further study the imaging properties of the processed AWGs with regards to spectral resolution in direct imaging mode, geometry-related defocus aberration, and polarization sensitivity of the spectral image. We identify phase error control, birefringence control, and aberration suppression as the three key areas of future research and development in the field of high-resolution AWG-based spectroscopy in astronomy
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