1,059 research outputs found

    Deutsche Geo-Forschungsarbeiten auf Island 1964/67

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    Sub-camera calibration of a Penta-camera

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    Penta cameras consisting of a nadir and four inclined cameras are becoming more and more popular, having the advantage of imaging also facades in built up areas from four directions. Such system cameras require a boresight calibration of the geometric relation of the cameras to each other, but also a calibration of the sub-cameras. Based on data sets of the ISPRS/EuroSDR benchmark for multi platform photogrammetry the inner orientation of the used IGI Penta DigiCAM has been analyzed. The required image coordinates of the blocks Dortmund and Zeche Zollern have been determined by Pix4Dmapper and have been independently adjusted and analyzed by program system BLUH. With 4.1 million image points in 314 images respectively 3.9 million image points in 248 images a dense matching was provided by Pix4Dmapper. With up to 19 respectively 29 images per object point the images are well connected, nevertheless the high number of images per object point are concentrated to the block centres while the inclined images outside the block centre are satisfying but not very strongly connected. This leads to very high values for the Student test (T-test) of the finally used additional parameters or in other words, additional parameters are highly significant. The estimated radial symmetric distortion of the nadir sub-camera corresponds to the laboratory calibration of IGI, but there are still radial symmetric distortions also for the inclined cameras with a size exceeding 5μm even if mentioned as negligible based on the laboratory calibration. Radial and tangential effects of the image corners are limited but still available. Remarkable angular affine systematic image errors can be seen especially in the block Zeche Zollern. Such deformations are unusual for digital matrix cameras, but it can be caused by the correlation between inner and exterior orientation if only parallel flight lines are used. With exception of the angular affinity the systematic image errors for corresponding cameras of both blocks have the same trend, but as usual for block adjustments with self calibration, they still show significant differences. Based on the very high number of image points the remaining image residuals can be safely determined by overlaying and averaging the image residuals corresponding to their image coordinates. The size of the systematic image errors, not covered by the used additional parameters, is in the range of a square mean of 0.1 pixels corresponding to 0.6μm. They are not the same for both blocks, but show some similarities for corresponding cameras. In general the bundle block adjustment with a satisfying set of additional parameters, checked by remaining systematic errors, is required for use of the whole geometric potential of the penta camera. Especially for object points on facades, often only in two images and taken with a limited base length, the correct handling of systematic image errors is important. At least in the analyzed data sets the self calibration of sub-cameras by bundle block adjustment suffers from the correlation of the inner to the exterior calibration due to missing crossing flight directions. As usual, the systematic image errors differ from block to block even without the influence of the correlation to the exterior orientation

    Deletion of annexin 2 light chain p11 in nociceptors causes deficits in somatosensory coding and pain behavior

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    The S100 family protein p11 (S100A10, annexin 2 light chain) is involved in the trafficking of the voltage-gated sodium channel Na(V)1.8, TWIK-related acid-sensitive K+ channel (TASK-1), the ligand-gated ion channels acid-sensing ion channel 1a (ASIC1a) and transient receptor potential vanilloid 5/6 (TRPV5/V6), as well as 5-hydroxytryptamine receptor 1B (5-HT1B), a G-protein-coupled receptor. To evaluate the role of p11 in peripheral pain pathways, we generated a loxP-flanked (floxed) p11 mouse and used the Cre-loxP recombinase system to delete p11 exclusively from nociceptive primary sensory neurons in mice. p11-null neurons showed deficits in the expression of NaV1.8, but not of annexin 2. Damage-sensing primary neurons from these animals show a reduced tetrodotoxin-resistant sodium current density, consistent with a loss of membrane-associated NaV1.8. Noxious coding in wide-dynamic-range neurons in the dorsal horn was markedly compromised. Acute pain behavior was attenuated in certain models, but no deficits in inflammatory pain were observed. A significant deficit in neuropathic pain behavior was also apparent in the conditional-null mice. These results confirm an important role for p11 in nociceptor function

    The Cepheid distance to the maser-host galaxy NGC 4258: Studying systematics with the Large Binocular Telescope

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    We identify and phase a sample of 81 Cepheids in the maser-host galaxy NGC 4258 using the Large Binocular Telescope (LBT), and obtain calibrated mean magnitudes in up to 4 filters for a subset of 43 Cepheids using archival HST data. We employ 3 models to study the systematic effects of extinction, the assumed extinction law, and metallicity on the Cepheid distance to NGC 4258. We find a correction to the Cepheid colors consistent with a grayer extinction law in NGC 4258 compared to the Milky Way (RV=4.9R_V =4.9), although we believe this is indicative of other systematic effects. If we combine our Cepheid sample with previously known Cepheids, we find a significant metallicity adjustment to the distance modulus of γ1=−0.61±0.21\gamma_1 = -0.61 \pm 0.21 mag/dex, for the Zaritsky et al. (1994) metallicity scale, as well as a weak trend of Cepheid colors with metallicity. Conclusions about the absolute effect of metallicity on Cepheid mean magnitudes appear to be limited by the available data on the metallicity gradient in NGC 4258, but our Cepheid data require at least some metallicity adjustment to make the Cepheid distance consistent with independent distances to the LMC and NGC 4258. From our ensemble of models and the geometric maser distance of NGC 4258 (μN4258=29.40±0.06\mu_{N4258} = 29.40 \pm 0.06 mag), we estimate μLMC=18.57±0.14\mu_{LMC} = 18.57 \pm 0.14 mag (51.82±3.2351.82 \pm 3.23 kpc).Comment: Accepted for publication in MNRAS. 28 pages, 13 figures, 11 tables. A brief video summarizing the key results of this paper can be found at http://youtu.be/ICTTNyxZ89

    Hierarchical Optimization: Fast and Robust Multiscale Stochastic Reconstructions with Rescaled Correlation Functions

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    © 2018 American Physical Society. Stochastic reconstructions based on universal correlation functions allow obtaining spatial structures based on limited input data or to fuse multiscale images from different sources. Current application of such techniques is severely hampered by the computational cost of the annealing optimization procedure. In this study we propose a novel hierarchical annealing method based on rescaled correlation functions, which improves both accuracy and computational efficiency of reconstructions while not suffering from disadvantages of existing speeding-up techniques. A significant order of magnitude gains in computational efficiency now allows us to add more correlation functions into consideration and, thus, to further improve the accuracy of the method. In addition, the method provides a robust multiscale framework to solve the universal upscaling or downscaling problem. The novel algorithm is extensively tested on binary (two-phase) microstructures of different genesis. In spite of significant improvements already in place, the current implementation of the hierarchical annealing method leaves significant room for additional accuracy and computational performance tweaks. As described here, (multiscale) stochastic reconstructions will find numerous applications in material and Earth sciences. Moreover, the proposed hierarchical approach can be readily applied to a wide spectrum of constrained optimization problems
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