1,113 research outputs found
How risky is the German pension system? The volatility of the internal rates of return
In this paper we analyze exemplarily the volatility of the internal rates of return of the German pension system over the life-cycle of an individual born in 1957. The outcome is compared to an alternative defined-contribution or defined-benefit policy. Based on the actual data, our results show the volatility of the internal rate of return to be significantly higher under the actual policy. We furthermore find that the sustainable internal rates of return are close to zero for the youngest male cohorts and positive for females for optimistic growth scenarios. In more realistic scenarios things turn worse. --Risk,internal rate of return,sustainability
Demographics and Volatile Social Security Wealth: Political Risks of Benefit Rule Changes in Germany
In this paper we address the question how the generosity of the benefit rule of the German public pension system has changed during the past three decades and how this development can be explained by demographic changes. Firstly, we illustrate the political risk of benefit rule changes for individuals. We find that depending on the birth year and the considered scenario the relative losses vary between 30 and nearly 60 percent. Secondly, we estimate how demographic developments have triggered these changes in generosity. Our results suggest that future developments of the old-age dependency ratio have an influence on the determination of generosity.social security wealth, demography, political economy, Germany
Measuring accrued-to-date liabilities of public pension systems: Method, data and limitations
This paper introduces the approach of the Freiburg model to quantify accrued-to-date liabilities (ADL) of public pension schemes. The presented framework has been applied to carry out benchmark calculations for 19 EU member states on behalf of the Eurostat/ECB Contact Group on Pensions. We will show that the Freiburg model represents a valuable instrument to calculate pension schemes' ADL on a relatively small data base. Furthermore, limitations and possible extensions of the model will be outlined. --
Andersonvilles of the North: The Myths and Realities of Northern Treatment of Civil War Confederate Prisoners
Prisoners of War In this important study of northern prisoner of war camps and policies governing them, James M. Gillispie counters many earlier treatments of the subject. Gillispie makes a compelling case that southern Lost Causers trying to counter condemnation of the South for the h...
Photoemission of a doped Mott insulator: spectral weight transfer and qualitative Mott-Hubbard description
The spectral weight evolution of the low-dimensional Mott insulator TiOCl
upon alkali-metal dosing has been studied by photoelectron spectroscopy. We
observe a spectral weight transfer between the lower Hubbard band and an
additional peak upon electron-doping, in line with quantitative expectations in
the atomic limit for changing the number of singly and doubly occupied sites.
This observation is an unconditional hallmark of correlated bands and has not
been reported before. In contrast, the absence of a metallic quasiparticle peak
can be traced back to a simple one-particle effect.Comment: 4 pages, 4 figures, related theoretical work can be found in
arXiv:0905.1276; shortene
Ultrasonic assisted milling of reinforced plastics
The milling of glass and carbon fibre reinforced plastics provides manufacturers from the automotive and aerospace industry with major challenges. The high carbon and glass fibre content increases the risk of insufficient production qualities. The abrasive fibres cause cutting edge rounding which results in the issue that the comparatively thick glass fibre cannot be reliably cut, while the carbon fiber is being less of a challenge. One approach to improve the production quality is the use of ultrasonic assisted milling. At the IWF tests have been undertaken to study the influence of ultrasonic assistance on workpiece quality, cutting forces and dust generation
Deep Learning for mapping retrogressive thaw slumps across the Arctic
Retrogressive thaw slumps (RTS) are typical landscape processes of thawing and degrading permafrost. To this point, their distribution and dynamics are almost completely undocumented across many regions in the permafrost domain, partially due to the lack of data and monitoring techniques in the past. We are tackling this shortcoming by creating a deep learning based semantic segmentation framework to detect RTS, using multi-spectral PlanetScope, derived topographic (ArcticDEM) and multi-temporal Landsat Trend data. We created a highly automated processing pipeline, which is designed to create reproducible results and to be flexible for multiple input features. The processing workflow is based on the pytorch deep-learning framework and includes a variety of different segmentation architectures (UNet, UNet++, DeepLabV3), backbones and includes common data transformation techniques such as augmentation or normalization.
We tested (training, validation) our DL based model in six different regions of 100 to 300 km² size across Canada (Banks Island, Tuktoyaktuk, Horton, Herschel Is.), and Siberia (Kolguev, Lena). We performed a regional cross-validation (5 regions training, 1 region validation) to test the spatial robustness and transferability of the algorithm. Furthermore, we tested different architectures backbones and loss-function to identify the best performing and most robust parameter sets. For training the models we created a training database of manually digitized and validated RTS polygons.
The resulting model performance varied strongly between different regions with maximum Intersection over Union (IoU) scores between 0.15 and 0.58. The strong regional variation emphasizes the need for sufficiently large training data, which is representative for the massive variety of RTS. However, the creation of good training data proved to be challenging due to the fuzzy definition and delineation of RTS, particularly on the lower part.
We have recently expanded our analysis to several RTS-rich regions across the Arctic (Fig.X) for the year 2021 and annual analysis (2018-2021) for RTS hot-spots, e.g. Banks Island, Peel Plateau and others. First model inference runs are promising for detecting RTS, but are still strongly overestimating the number and area of RTS, due to an excessive number of false positives. Model performance however, varies strongly between regions. Due to the strong variability of landscapes with RTS, we expect an improvement in model performance with an increase in the number and spatial distribution of training datasets. The community driven formation of the IPA Action Group RTSIn, which aims to create standardized RTS digitization protocols and training datasets for deep/machine-learning purposes will be a great boost for our purpose.
With our standardized processing pipeline (preprocessing, training, inference), which allows to add more features based on user interest and data availability,, we tested our workflow for surface water and pingos with a mixture of publically available (Jones et al) and digitized data (Grosse pingos, Nitze water). These tests produced very good results and showed that the designed workflow is transferrable beyond the segmentation of RTS only.
In the near future, we are aiming to integrate the community based training data and further gradually improve our training database. Within the framework of the ML4Earth project, we will create a temporal and pan-arctic monitoring system for RTS based on our highly automated processing chain. This will enable us to better understand pan-arctic RTS dynamics, their influencing factors, and consequences. Combining these spatial-temporal datasets with volumetric change information and carbon stock information will enable us to better quantify the consequences of thaw slumping across the permafrost domain
Supercomplex-Associated Cox26 Protein Binds to Cytochrome \u3cem\u3ec\u3c/em\u3e Oxidase
Here we identified a hydrophobic 6.4 kDa protein, Cox26, as a novel component of yeast mitochondrial supercomplex comprising respiratory complexes III and IV. Multi-dimensional native and denaturing electrophoretic techniques were used to identify proteins interacting with Cox26. The majority of the Cox26 protein was found non-covalently bound to the complex IV moiety of the IIIâIV supercomplexes. A population of Cox26 was observed to exist in a disulfide bond partnership with the Cox2 subunit of complex IV. No pronounced growth phenotype for Cox26 deficiency was observed, indicating that Cox26 may not play a critical role in the COX enzymology, and we speculate that Cox26 may serve to regulate or support the Cox2 protein. Respiratory supercomplexes are assembled in the absence of the Cox26 protein, however their pattern slightly differs to the wild type IIIâIV supercomplex appearance. The catalytic activities of complexes III and IV were observed to be normal and respiration was comparable to wild type as long as cells were cultivated under normal growth conditions. Stress conditions, such as elevated temperatures resulted in mild decrease of respiration in non-fermentative media when the Cox26 protein was absent
Volume Averaging of Spectral-Domain Optical Coherence Tomography Impacts Retinal Segmentation in Children
Purpose: To determine the influence of volume averaging on retinal layer thickness measures acquired with spectral-domain optical coherence tomography (SD-OCT) in children.
Methods: Macular SD-OCT images were acquired using three different volume acquisition settings (i.e., ART 1, 3, and 9 volumes) in children enrolled in a prospective OCT study. Total retinal, retinal nerve fiber layer, ganglion cell layer, inner plexiform layer, inner nuclear layer, and outer plexiform layer thicknesses were measured around an ETDRS grid using beta version automated segmentation software for the Spectralis. The magnitude of manual segmentation required to correct the automated segmentation was classified as either minor (less than 12 lines adjusted), moderate (\u3e12 andadjusted), severe (\u3e26 and \u3c 48 lines adjusted) or fail (\u3e 48 lines adjusted or could not adjust due to poor image quality). The frequency of each edit classification was assessed for each volume setting. Thickness, paired difference and 95% limits of agreement of each anatomic quadrant were compared across volumes.
Results: 75 subjects (median age 11.8 years, range 4.3- 18.5 years) contributed 75 eyes. Less than 5% of the 9 and 3 volume scans required more than minor manual segmentation corrections, compared to 71% of 1 volume scans. The inner (3mm) region demonstrated similar measures across all layers, regardless of volume number. The one volume scans demonstrated greater variability of the RNFL thickness, compared to the other volumes in the outer (6mm) region.
Discussion: In children, a minimum acquisition setting of ART 3 for SD-OCT volumes should be obtained to reduce retinal layer segmentation errors
Geodetic Work During the Reconstruction of Jan Neruda Square in Ostrava
Obsahom tejto diplomovej prĂĄce je popĂsaĹĽ postup geodetickĂ˝ch prĂĄc poÄas revitalizĂĄcie nĂĄmestia Jana Nerudy v mestskej Äasti Ostrava-Poruba ktorĂĄ je sĂşÄasĹĽou rozsiahlych rekonĹĄtrukÄnĂ˝ch prĂĄc v okolĂ lokality. PrĂĄca obsahuje popis lokality, popĂsanie jednotlivĂ˝ch fĂĄz geodetickĂ˝ch prĂĄc, pouĹžitĂŠ metĂłdy merania a pomĂ´cky, rozdelenie geodetickĂ˝ch a prĂĄce na danom projekte rekultivĂĄcie nĂĄmestia, vrĂĄtane ÄastĂ kancelĂĄrskych prĂĄc. PrĂlohy obsahujĂş vĂ˝slednĂŠ geodetickĂŠ protokoly.The content of this diploma thesis is to describe the process of geodetic works during the revitalization of Jan Neruda Square in the Ostrava-Poruba district, which is part of extensive reconstruction work in the vicinity of the site. The work contains a description of the site, a description of the various phases of geodetic works, the measurement methods used and aids, the division of geodetics, and works on the project of reclamation of the square, including parts of office works. The appendices contain the resulting geodetic protocols.544 - Katedra geodĂŠzie a dĹŻlnĂho mÄĹictvĂvelmi dobĹ
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