Luhmann T.,University of Oldenburg
ISPRS Journal of Photogrammetry and Remote Sensing | Year: 2010
This article summarizes recent developments and applications of digital photogrammetry in industrial measurement. Industrial photogrammetry covers a wide field of different practical challenges in terms of specified accuracy, measurement speed, automation, process integration, cost-performance ratio, sensor integration and analysis. On-line and off-line systems are available, offering general purpose systems on the one hand and specific turnkey systems for individual measurement tasks on the other. Verification of accuracy and traceability to standard units with respect to national and international standards is inevitable in industrial practice. System solutions can be divided into the measurement of discrete points, deformations and motions, 6DOF parameters, 3D contours and 3D surfaces. Recent and future developments concentrate on higher dynamic applications, integration of systems into production chains, multi-sensor solutions and still higher accuracy and lower costs. © International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS).
Ryabov A.B.,University of Oldenburg |
Blasius B.,University of Oldenburg
Ecology Letters | Year: 2011
Resource competition is a fundamental interaction in natural communities. However, little remains known about competition in spatial environments where organisms are able to regulate resource distributions. Here, we analyse the competition of two consumers for two resources in a one-dimensional habitat in which the resources are supplied from opposite sides. We show that the success of an invading species crucially depends on the slope of the resource gradients shaped by the resident. Our analysis reveals that parameter combinations, which lead to coexistence in a uniform environment, may favour alternative stable states in a spatial system, and vice versa. Furthermore, differences in growth rate, mortality or dispersal abilities allow a consumer to coexist stationarily with - or even outcompete - a competitor with lower resource requirements. Applying our theory to a phytoplankton model, we explain shifts in the community structure that are induced by environmental changes. © 2011 Blackwell Publishing Ltd/CNRS.
Bormann H.,University of Oldenburg
Climatic Change | Year: 2011
Potential evapotranspiration models very often are important part of hydrological catchment models to calculate potential evapotranspiration (PET) which then is used to estimate actual evapotranspiration considering the soil moisture status. As many different approaches exist, the question arises in which way the choice of the PET model affects the impact of climate change on the calculated water balance? Therefore, 18 different PET models were compared with respect to their sensitivity to observed climate change. Long-term climate data of six German climate stations were used to identify changes in the climate data itself and changes in the calculated PET. The results show that all investigated PET models are sensitive to significant trends in climate data. However, it is also shown that all models show different sensitivities, and that the sensitivities cannot be grouped in terms of different types of PET models such as the aerodynamic concept, radiation or temperature based approaches and combination equations. Predominantly, the variability within a group of models of the same type is comparable to the variability between different model types. Therefore it can be concluded that PET models should be validated in a regional context before they are applied to a certain region within a climate change study despite the poor availability of long-term PET measurements. © 2010 Springer Science+Business Media B.V.
Gerkmann T.,University of Oldenburg
IEEE Transactions on Signal Processing | Year: 2014
While most short-time discrete Fourier transform-based single-channel speech enhancement algorithms only modify the noisy spectral amplitude, in recent years the interest in phase processing has increased in the field. The goal of this paper is twofold. First, we derive Bayesian probability density functions and estimators for the clean speech phase when different amounts of prior knowledge about the speech and noise amplitudes is given. Second, we derive a joint Bayesian estimator of the clean speech amplitudes and phases, when uncertain a priori knowledge on the phase is available. Instrumental measures predict that by incorporating uncertain prior information of the phase, the quality and intelligibility of processed speech can be improved both over traditional phase insensitive approaches, and approaches that treat prior information on the phase as deterministic. © 1991-2012 IEEE.
Richter-Landsberg C.,University of Oldenburg |
Leyk J.,University of Oldenburg
Acta Neuropathologica | Year: 2013
The failure to clear misfolded or aggregated proteins from the cytoplasm of nerve cells and glia is a common pathogenic event in a variety of neurodegenerative disorders. This might be causally related to defects in the major proteolytic systems, i.e., the ubiquitin-proteasomal system and the autophagic pathway. Large protein aggregates and defective organelles are excluded from the proteasome. They can be degraded only by macroautophagy, which is a highly selective process. It requires p62 to act as a bridge connecting ubiquitinated protein aggregates and autophagosomes, and the tubulin deacetylase histone deacetylase 6 (HDAC6). HDAC6 has recently been identified as a constituent in Lewy bodies of Parkinson disease and glial cytoplasmic inclusions of multiple system atrophy. It is considered a sensor of proteasomal inhibition and a cellular stress surveillance factor, and plays a central role in autophagy by controlling the fusion process of autophagosomes with lysosomes. Upon proteasomal inhibition, HDAC6 is relocated and recruited to polyubiquitin-positive aggresomes. Tubulin acetylation is a major consequence of HDAC6 inhibition, and HDAC6 inhibition restores microtubule (MT)-dependent transport mechanisms in neurons. This suggests the involvement of HDAC6 in neurodegenerative diseases. Furthermore, the protein tau seems to be a substrate for HDAC6. Tau acetylation impairs MT assembly and promotes tau fibrillization in vitro. It has been suggested that acetylation and phosphorylation of tau at multiples sites may act synergistically in the pathogenesis of tau fibrillization. In this review, we will survey the process of aggresome formation, macroautophagy and the role of autophagosomal proteins and HDAC6 in inclusion body formation. © Springer-Verlag Berlin Heidelberg 2013.
Mattes J.,University of Oldenburg
Regional Studies | Year: 2012
Mattes J. Dimensions of proximity and knowledge bases: innovation between spatial and non-spatial factors, Regional Studies. Innovations face the challenge of integrating knowledge from heterogeneous sources by establishing an appropriate level of proximity. Proximity is thereby not a purely spatial phenomenon, but also includes organizational, institutional, social and cognitive dimensions. Geographical and social proximity are thereby auxiliary factors, whereas organizational, institutional and cognitive proximity act as critical enablers for learning. These dimensions can be connected to synthetic, analytical and symbolic knowledge bases. They thereby trigger a dynamic trade-off between various forms of proximity, whereby the proximity form varies depending on the underlying knowledge base. Hence, innovation is a complex combination of spatial and non-spatial factors. © 2012 Copyright Regional Studies Association.
Kunzel S.,University of Oldenburg
Journal of European Social Policy | Year: 2012
Active inclusion reforms are radically transforming social policies in Europe. Consequently, the welfare state is changing from a social citizenship approach based on uniform benefits and services towards a system of individualized, targeted welfare intervention. Reforms therefore involve a fundamental re-organization of welfare provision. This transformation is usually discussed as a matter of national regimes for active inclusion and European diffusion of 'good' governance. However, active inclusion policies rely on a different social policy approach implying differentiated implementation processes. The implementation of active inclusion reforms can therefore only be understood by taking into account the local level. A series of local studies on French and German minimum income schemes raises questions about national accounts of these schemes, which depict a shift towards workfare. By contrast, this article reveals local variation between market-oriented, bureaucratic and participatory active inclusion strategies dependent on the distinct local governance arrangements. © SAGE Publications 2012.
Springmann M.,University of Oldenburg
Nature Climate Change | Year: 2014
Net emissions transfers via international trade from developing to developed countries have increased fourfold in the past two decades - from 0.4 GtCO 2 in 1990 to 1.6 GtCO 2 in 2008. Consumption of goods and services in developed countries is one of the main driving forces of those emissions transfers. Therefore several proposals have been made to assign the responsibility for those emissions to the beneficiary, that is, to the consumer. Although consumption-based analyses have become popular, few proposals have been made for integrating emissions transfers into actual policy making. This study advances and critically evaluates three potential policy options that could be integrated in the climate-policy framework of developed countries. An energy-economic model with global coverage is used for the analysis. I find that connecting emissions transfers to international offset responsibilities is the most promising option from an environmental and economic perspective and may provide another rationale for international climate finance. The two alternative policy options of adjusting domestic emissions targets in developed countries and of implementing carbon-related tariffs and export subsidies are found to be environmentally ineffective in the latter case and economically detrimental, especially for developing countries, in both cases. © 2014 Macmillan Publishers Limited.
Kaupp G.,University of Oldenburg
CrystEngComm | Year: 2011
A systematic survey over the varied use of milling with metals according to reaction types is presented. After the mechanistic distinction of the brittle milling and ductile kneading also for large-scale industrial processes, the consequences for improved applications are exemplified. This covers milling of metals with infinitely covalent non-metals, with metal salts, molecular crystals and carbon, with metal hydrides, with gases (H2, N2, O2), with semi-metals (As, B, Ge, Se, Si, Te), with organic halides and ketones, and with other metals for mechanical alloying. Homogeneous alloys and nanocomposites are distinguished. Metal-metal mechanical alloying is subdivided under solid solutions of immiscible metals, metal-metal nanocomposites, and intermetallics (crystalline and amorphous). The latter is further subdivided into brittle-brittle, brittle-ductile, and ductile-ductile combinations and followed by superalloy composites. Binary alloys are primarily used for the exemplification in order to limit the already enormous field. Various techniques for the decreasing of unduly long milling times become evident from the mechanistic considerations. Optimal choice of the temperature in heat-controlled mills featuring upgrading and adjustable milling conditions is substantial. This is equally important for milling and for ductile kneading. Essential parameters are the selected temperature and optimal (not maximal) milling impact (for example ball mass, size and speed, ball to powder ratio, chamber filling level) for avoiding clogging or lumping instead of generating the maximal number of collisions. Further tools are cycle operation and semi-continuous processing in closed systems for milling and easy collection under vacuum or with pressurized gases. © 2011 The Royal Society of Chemistry.
Muller H.L.,University of Oldenburg
Endocrine Reviews | Year: 2014
This report is a review of findings on the diagnosis, treatment, clinical course, and prognosis of craniopharyngioma patients. Craniopharyngiomas are rare, partly cystic and calcified embryonic malformations of the sellar/parasellar region with low histological grade (WHO Io). A bimodal age distribution has been shown, with peak incidence rates in childhood-onset at 5-14 years and adult-onset craniopharyngioma at 50-74 years. Clinical manifestations are related to hypothalamic/pituitary deficiencies, visual impairment, and increased intracranial pressure. If the tumor is favorably localized, the therapy of choice is complete resection, with care taken to preserve optical and hypothalamic functions. In patients with unfavorable tumor localization (ie, hypothalamic involvement), recommended therapy is a limited hypothalamus-sparing surgical strategy followed by local irradiation. Although overall survival rates are high (92%), recurrences and progressions are frequent. Irradiation has proven effective in reducing recurrences and progression, and timing of postsurgical irradiation in childhood-onset cases is currently under investigation in a randomized multinational trial (KRANIOPHARYNGEOM 2007). Anatomical involvement and/or surgical lesions of posterior hypothalamic areas can result in serious quality of life-compromising sequelae such as hypothalamic obesity, psychopathological symptoms, and/or cognitive problems. It is crucial that craniopharyngioma be managed as a frequently chronic disease, providing ongoing care of pediatric and adult patients' clinical and quality of life consequences by experienced multidisciplinary teams. © 2014 by the Endocrine Society.