1,187 research outputs found
Relating color discrimination to photopigment genes in deutan observers
AbstractDeutan observers are a heterogeneous group, varying nearly continuously from deuteranomalous trichromats with fine chromatic discrimination in the red/green range to deuteranopes who have none. We sought to relate chromatic discriminative ability among deutans measured psychophysically (phenotypes) to observers' separation between long-wave visual pigments inferred from visual pigment genes (genotypes). If middle-wave pigment genes are assumed not to be expressed in these deutan observers there is a clear relation between phenotype and genotype
Volume Rendering with Advanced GPU Scheduling Strategies
Modern GPUs are powerful enough to enable interactive display of high-quality volume data even despite the fact that many volume rendering methods do not present a natural fit for current GPU hardware. However, there still is a vast amount of computational power that remains unused due to the inefficient use of the available hardware. In this work, we demonstrate how advanced scheduling methods can be employed to implement volume rendering algorithms in a way that better utilizes the GPU by example of three different state-of-the-art volume rendering techniques
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Learning under Distributed Weak Supervision
The availability of training data for supervision is a frequently encountered bottleneck of medical image analysis methods. While typically established by a clinical expert rater, the increase in acquired imaging data renders traditional pixel-wise segmentations less feasible. In this paper, we examine the use of a crowdsourcing platform for the distribution of super-pixel weak annotation tasks and collect such annotations from a crowd of non-expert raters. The crowd annotations are subsequently used for training a fully convolutional neural network to address the problem of fetal brain segmentation in T2-weighted MR images. Using this approach we report encouraging results compared to highly targeted, fully supervised methods and potentially address a frequent problem impeding image analysis research
Wirkungen differenzierter Bodenbearbeitungssysteme im Dauerversuch Scheyern
After a 12-year differing tillage in a 7-phase crop rotation with lay, potatoes, wheat, sunflowers, lay, wheat and rye it was found, that mouldboard-ploughing (P) resulted in less weed. Crop yields were as high as in the treatment with ploughing after lay and chiselling after potatoes and sunflowers (B). Lowest yields were obtained without ploughing but using the chisel (G). Weeds, esp. grasses, resulted in a huge competition for crops esp. after lay. Profit margins were highest in B due to lower expenditures for tillage and lowest in G. Soil organic carbon amounts differed by 1,5 t/ha and earthworm biomass by 0,25 t/ha between P and G after 12 years. It can be summed up for this experiment that G was not sustainable due to weeds and declining yields, and that B resulted in best economic profit, increasing SOM content and seems to be a sustainable compromise
Spin relaxation times of 2D holes from spin sensitive bleaching of inter-subband absorption
We present spin relaxation times of 2D holes obtained by means of spin
sensitive bleaching of the absorption of infrared radiation in p-type
GaAs/AlGaAs quantum wells (QWs). It is shown that the saturation of
inter-subband absorption of circularly polarized radiation is mainly controlled
by the spin relaxation time of the holes. The saturation behavior has been
determined for different QW widths and in a wide temperature range with the
result that the saturation intensity substantially decreases with narrowing of
the QWs. Spin relaxation times are derived from the measured saturation
intensities by making use of calculated (linear) absorption coefficients for
direct inter-subband transitions. It is shown that spin relaxation is due to
the D'yakonov-Perel' mechanism governed by hole-hole scattering. The problem of
selection rules is addressed.Comment: 14 pages, 5 figure
Wirkungen des Ökologischen Landbaus auf Bodenerosion durch Wasser
Soil erosion is still one of the major problems in relation to soil protection and it is necessary to have tools for assessment of soil losses. Changes of the farm structure like building a biogas power plant or changing the cropping system may affect soil losses. Before implementing those changes knowledge is necessary. The implemen-tation and application of an adequate tool is shown on the research farm Scheyern. The results of this model were compared with measured values for soil losses to demonstrate the applicability. Beside this attention is invited to conditions of ecological farming which have an impact on soil erosion
Langzeituntersuchung der Kohlenstoff- und Stickstoffkreisläufe eines intensiven ökologischen Betriebssystems – am Beispiel des Versuchsgutes Scheyern
Carbon, nitrogen and energy flows are considered as an appropriate basis to characterize farming systems and to evaluate the environmental effects. Using the model REPRO the carbon and nitrogen flows of the experimental farm “Klostergut Scheyern” have been evaluated since 1991 on the basis of complete cultivation data as well as with the help of detailed site and weather data. Thus “Scheyern” is characterised as an intensive organic farming system with a high turnover of C and N
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