oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2020 ( 2 )

2019 ( 234 )

2018 ( 288 )

2017 ( 313 )

Custom range...

Search Results: 1 - 10 of 138900 matches for " K. Born "
All listed articles are free for downloading (OA Articles)
Page 1 /138900
Display every page Item
Probabilistic downscaling of precipitation data in a subtropical mountain area: a two-step approach
R. Haas ,K. Born
Nonlinear Processes in Geophysics (NPG) , 2011,
Abstract: In this study, a two-step probabilistic downscaling approach is introduced and evaluated. The method is exemplarily applied on precipitation observations in the subtropical mountain environment of the High Atlas in Morocco. The challenge is to deal with a complex terrain, heavily skewed precipitation distributions and a sparse amount of data, both spatial and temporal. In the first step of the approach, a transfer function between distributions of large-scale predictors and of local observations is derived. The aim is to forecast cumulative distribution functions with parameters from known data. In order to interpolate between sites, the second step applies multiple linear regression on distribution parameters of observed data using local topographic information. By combining both steps, a prediction at every point of the investigation area is achieved. Both steps and their combination are assessed by cross-validation and by splitting the available dataset into a trainings- and a validation-subset. Due to the estimated quantiles and probabilities of zero daily precipitation, this approach is found to be adequate for application even in areas with difficult topographic circumstances and low data availability.
Melting of Northern Greenland during the last interglacial
A. Born,K. H. Nisancioglu
The Cryosphere Discussions , 2011, DOI: 10.5194/tcd-5-3517-2011
Abstract: The Greenland ice sheet (GrIS) is losing mass at an increasing rate, making it the primary contributor to global eustatic sea level rise. Large melting areas and rapid thinning at its margins has raised concerns about its stability. However, it is conceivable that these observations represent the transient adjustment of the fastest reacting parts of the ice sheet, masking slower processes that dominate the long term fate of the GrIS and its contribution to sea level rise. Studies of the geological past provide valuable information on the long term response of the GrIS to warm periods. We simulate the GrIS during the Eemian interglacial, a period 126 000 yr before present (126 ka) with Arctic temperatures comparable to projections for the end of this century. The northeastern part of the GrIS is unstable and retreats significantly, despite moderate melt rates. Unlike the south and west, strong melting in the northeast is not compensated by high accumulation, or fast ice flow. The analogy with the present warming suggests that in coming decades, positive feedbacks could increase the rate of mass loss of the northeastern GrIS, exceeding the currently observed melting in the south.
Melting of Northern Greenland during the last interglaciation
A. Born,K. H. Nisancioglu
The Cryosphere , 2012, DOI: 10.5194/tc-6-1239-2012
Abstract: Using simulated climate data from the comprehensive coupled climate model IPSL CM4, we simulate the Greenland ice sheet (GrIS) during the Eemian interglaciation with the three-dimensional ice sheet model SICOPOLIS. The Eemian is a period 126 000 yr before present (126 ka) with Arctic temperatures comparable to projections for the end of this century. In our simulation, the northeastern part of the GrIS is unstable and retreats significantly, despite moderate melt rates. This result is found to be robust to perturbations within a wide parameter space of key parameters of the ice sheet model, the choice of initial ice temperature, and has been reproduced with climate forcing from a second coupled climate model, the CCSM3. It is shown that the northeast GrIS is the most vulnerable. Even a small increase in melt removes many years of ice accumulation, giving a large mass imbalance and triggering the strong ice-elevation feedback. Unlike the south and west, melting in the northeast is not compensated by high accumulation. The analogy with modern warming suggests that in coming decades, positive feedbacks could increase the rate of mass loss of the northeastern GrIS, exceeding the recent observed thinning rates in the south.
Fine-scale precipitation structure of a cold front and the problem of the representativeness error
H. Huebener, K. Born,M. Kerschgens
Advances in Geosciences (ADGEO) , 2007,
Abstract: The simulation of local scale precipitation with nested models often suffers from large errors in the boundary rows. Advection of precipitation into the model domain of the small scale model can lead to an overestimation of precipitation in the boundary grid cells of the nested model and a drying of the interior grid area. Consequently, the finer scale structure of rainfall events of the small scale model can not evolve. These errors result from three main sources: "dynamical", "scale", and "parameterization" problems. As a first step to reduce the "parameterization" boundary errors, we propose a nesting procedure where rainwater from the driving larger scale model is converted to cloud water in the smaller scale model. The nesting method is applied to a case study of heavy rainfall in semi-arid southern Morocco. The results show the elimination of erroneous excessive rainfall in the boundary rows and slightly enhanced rainfall in the interior of the nested model domain. Additionally, fine scale structures in the precipitation patterns develop. The excessive surface runoff is clearly diminished in comparison to the standard nesting procedure. The proposed approach enables scale consistent precipitation patterns resulting from model physics and grid-resolution of the smaller scale model for the complete model domain.
Warm Nordic Seas delayed glacial inception in Scandinavia
A. Born, M. Kageyama,K. H. Nisancioglu
Climate of the Past (CP) & Discussions (CPD) , 2010,
Abstract: We simulate the last glacial inception, 115 000 years ago, with a three dimensional thermomechanical ice sheet model of the Northern Hemisphere, forced by a comprehensive coupled climate model. High oceanic heat transport into the Nordic Seas prevents large scale ice growth over Scandinavia. Glacial inception in the region starts on the highest mountains in the south when sea surface temperatures in the Nordic Seas are reduced by at least 3 °C. Ice growth in Northern Scandinavia requires a cooling by at least 4 °C. This is in good agreement with marine proxy data from the Nordic Seas and North Atlantic as well as available terrestrial data. This study thus provides a physical understanding and revised timing of the first glacier advance over Scandinavia.
Warm Nordic Seas delayed glacial inception in Scandinavia
A. Born,M. Kageyama,K. H. Nisancioglu
Climate of the Past Discussions , 2010, DOI: 10.5194/cpd-6-1503-2010
Abstract: We simulate the last glacial inception, 115 000 years ago, with a three dimensional thermomechanical ice sheet model of the Northern Hemisphere, forced by a comprehensive coupled climate model. High oceanic heat transport into the Nordic Seas prevents large scale ice growth over Scandinavia. Glacial inception in the region starts on the highest mountains in the south when sea surface temperatures in the Nordic Seas are reduced by at least 3 °C. Ice growth in Northern Scandinavia requires a cooling by at least 4 °C. This is in good agreement with marine proxy data from the Nordic Seas and North Atlantic as well as available terrestrial data. This study thus provides a physical understanding and revised timing of the first glacier advance over Scandinavia.
STRUCTURAL DETERMINANTS IN THE CALCITONIN RECEPTOR-LIKE RECEPTOR (CRLR) IMPORTANT FOR CGRP AND ADRENOMEDULLIN (AM) RECEPTOR FUNCTION OF CRLR/RECEPTOR-ACTIVITY-MODIFYING PROTEIN (RAMP) 1 AND CRLR/RAMP2 HETERODIMERS
W. Born,K. Leuthauser,R. Gujer,R. Muff
The Scientific World Journal , 2001, DOI: 10.1100/tsw.2001.405
Abstract:
Correlating cell architecture with osteogenesis: first steps towards live single cell monitoring
A-K Born,M Rottmar,S Lischer,M Pleskova
European Cells and Materials (ECM) , 2009,
Abstract: Cell shape and regulation of biological processes such as proliferation and differentiation are to a large degree connected. Investigation of the possible relationship between cell shape and function is therefore important for developing new material concepts for medical applications as well as developing novel cell based sensors. Cell spreading requires a firm contact with the underlying substrate, with focal contacts (FC) being the primary sites of adhesion. They consist of a large number of clustered transmembrane proteins (integrins). FC integrins connect the cell cytoskeleton with the cell substratum. It has been demonstrated that cell spreading increases osteoblast differentiation in pre-osteoblastic progenitors. The gradual process of osteogenesis can be followed by different proteins being expressed at various time points, comprising early (e.g., bone-specific alkaline phosphatase (bALP)) and late genes (e.g., osteocalcin (OC)). In the present study we have used immunohistochemistry and RT-PCR to determine osteogenic differentiation of human bone cells (HBC). For online monitoring, fluorescently-tagged actin and vinculin were used for transfection of HBCs. Transfection of HBCs with an OC promoter gene construct allowed us to online monitor the gradual process of osteogenesis. We found distinct changes in cell architecture upon osteogenic differentiation thus providing evidence for the connection between cell shape and functional state.
Gênero, trajetória de vida e biografia: desafios metodológicos e resultados empíricos
Born, Claudia;
Sociologias , 2001, DOI: 10.1590/S1517-45222001000100011
Abstract: in order to examine social change of gender specific life courses in germany, results and methodological procedures an empirical research project, which deals with life course and biography research under the perspective of gender, will be presented. as social change in the life course depends on the interlacing of individual actors and social structure, the analysis of life course patterns requires an innovative mixed-methods approach - the integration of quantitative techniques. after a theoretical discussion of the opportunities and restrictions associated with linking qualitative and quantitative methods, their integration is illustrated in practice (with examples of our own research). the research design and the results show the advantages and fruitfulness of the mixed-methods approach within this research project.
Browser-Based Covert Data Exfiltration
Kenton Born
Computer Science , 2010,
Abstract: Current best practices heavily control user permissions on network systems. This effectively mitigates many insider threats regarding the collection and exfiltration of data. Many methods of covert communication involve crafting custom packets, typically requiring both the necessary software and elevated privileges on the system. By exploiting the functionality of a browser, covert channels for data exfiltration may be created without additional software or user privileges. This paper explores novel methods of using a browser's JavaScript engine to exfiltrate documents over the Domain Name System (DNS) protocol without sending less covert Hypertext Transfer Protocol (HTTP) requests.
Page 1 /138900
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.