788 research outputs found
Variability of blowfly head optomotor responses
No full textRosner R, Egelhaaf M, Grewe J, Warzecha A-K. Variability of blowfly head optomotor responses. Journal of Experimental Biology. 2009;212(8):1170-1184
Impact of climate variability on tropospheric ozone
No full textA simulation with the climate–chemistry model (CCM) E39/C is presented, which covers both the troposphere and stratosphere
dynamics and chemistry during the period 1960 to 1999. Although the CCM, by its nature, is not exactly representing observed
day-by-day meteorology, there is an overall model's tendency to correctly reproduce the variability pattern due to an inclusion of
realistic external forcings, like observed sea surface temperatures (e.g. El Niño), major volcanic eruption, solar cycle,
concentrations of greenhouse gases, and Quasi-Biennial Oscillation. Additionally, climate–chemistry interactions are included, like
the impact of ozone, methane, and other species on radiation and dynamics, and the impact of dynamics on emissions (lightning).
However, a number of important feedbacks are not yet included (e.g. feedbacks related to biogenic emissions and emissions due to
biomass burning). The results show a good representation of the evolution of the stratospheric ozone layer, including the ozone
hole, which plays an important role for the simulation of natural variability of tropospheric ozone. Anthropogenic NOx emissions
are included with a step-wise linear trend for each sector, but no interannual variability is included. The application of a number of
diagnostics (e.g. marked ozone tracers) allows the separation of the impact of various processes/emissions on tropospheric ozone
and shows that the simulated Northern Hemisphere tropospheric ozone budget is not only dominated by nitrogen oxide emissions
and other ozone pre-cursors, but also by changes of the stratospheric ozone budget and its flux into the troposphere, which tends to
reduce the simulated positive trend in tropospheric ozone due to emissions from industry and traffic during the late 80s and early
90s. For tropical regions the variability in ozone is dominated by variability in lightning (related to ENSO) and stratosphere–
troposphere exchange (related to Northern Hemisphere Stratospheric dynamics and solar activity). Since tropospheric background
chemistry is regarded only, the results are quantitatively limited with respect to derived trends. However, the main results are
regarded to be robust.
Although the horizontal resolution is rather coarse in comparison to regional models, such kind of simulations provide useful
and necessary information on the impact of large-scale processes and inter-annual/decadal variations on regional air quality
150th anniversary of the Bethel epilepsy center in Germany: An important milestone in the evolution of epilepsy care
No full textGrewe P, Bien C. 150th anniversary of the Bethel epilepsy center in Germany: An important milestone in the evolution of epilepsy care. Seizure. 2017;53:110-113
Multirate coding of 3D medical data
No full textThe last generation medical imaging equipment produce multidimensional (3D or 3D+time) data distributions. On a coding perspective, it is reasonable to expect that the exploitation of the full dimensional correlation among data samples would lead to a sensible improvement in compression performances, especially for isotropic datasets. We propose a fully three-dimensional wavelet-based coding system providing a finely-graded up to lossless data representation in a single bistream. The data are first decorrelated by a 3D discrete wavelet transform, performed by the non-linear lifting scheme mapping integers to integers. This enables the lossless mode and permits the in-place implementation of the transform at a reduced computational complexity. The coding scheme is inspired to the layered-zero coding proposed by Taubman and Zakhor (1994), extended to handle fully 3D subband structures. Performances are characterized with respect to both the 2D version of the same algorithm and the JPEG standard. The rate-saving is strongly influenced by the amount of the data correlation in the z dimension, ranging between 16.5% and 5.5% for the considered datasets
Evaluation of virtual reality applications for neuropsychological assessment and rehabilitation in patients with epilepsy and healthy participants
No full textGrewe P. Evaluation of virtual reality applications for neuropsychological assessment and rehabilitation in patients with epilepsy and healthy participants. Bielefeld; 2013
Epilepsy Center Bethel, Bielefeld, Germany
No full textGrewe P, Siedersleben C, Bien CG. Epilepsy Center Bethel, Bielefeld, Germany. Epilepsy & Behavior. 2017;76:S17-S20
A trans-splicing group I intron and tRNA-hyperediting in the mitochondrial genome of the lycophyte Isoetes engelmannii
No full textGrewe F, Viehöver P, Weisshaar B, Knoop V. A trans-splicing group I intron and tRNA-hyperediting in the mitochondrial genome of the lycophyte Isoetes engelmannii. Nucleic Acids Research. 2009;37(15):5093-5104
Comparison between global models and measurements of trace gases during TROCCINOX
No full textAirborne trace gas measurements carried out over southern Brazil during TROCCINOX-1 with the Falcon aircraft are compared to results from three global models: ECHAM, MATCH and TM4. The agreement between the models, with different parameterizations for lightning-produced NOX (=NO+NO2), and the measurements is investigated along single flight tracks. A new parameterization based on the mass flux in the updrafts [Grewe et al., 2001; Kurz and Grewe, 2002] shows promising results in comparison to the more commonly used parameterization based on the cloud top height [Price and Rind, 1992]. The most realistic model results for the total amount of lightning-produced NOX on the global scale were achieved with 5 Tg(N) yr-1
Application oriented Wavelet-based coding of volumetric medical data
No full textWavelet based coding of medical dat
McGregor, house on the corner of Grewe Street and Darling Street
No full texta247-a-1-i-4-1-36.jpg derived from archival TIFF file. Digital copies were created from a selection of drawings in the original James Walton manuscript collection (MS 247) held in the Manuscripts Section of the Stellenbosch Library and Information Service Collection.This illustration was published in Double-storeyed flat-roofed buildings of the rural Cape by James Walton. Cape Town : Saayman & Weber, 1993, p. 60.Photograph depicting a house on the corner of Grewe Street and Darling Street, McGregor
- …
