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Search Results: 1 - 10 of 45154 matches for " Michael Schumann "
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Service-Fingerprinting mittels Fuzzing
Michael Hanspach,Ralf Schumann,Stefan Schemmer,Sebastian Vandersee
Computer Science , 2014,
Abstract: Service fingerprinting (i.e. the identification of network services and other applications on computing systems) is an essential part of penetration tests. The main contribution of this paper is a study on the improvement of fingerprinting tools. By applying mutation-based fuzzing as a fingerprint generation method, subtle differences in response messages can be identified. These differences in response messages provide means for the differentiation and identification of network services. To prove the feasibility of the approach, an implementation of a fingerprinting tool for ftp servers is presented and compared to preexisting fingerprinting tools. As a result of this study it is shown that mutation-based fuzzing is an appropriate method for service fingerprinting that even offers advantages over preexisting methods.
Sexual Dysfunction before and after Cardiac Rehabilitation
J rg Schumann,Michael J. Zellweger,Marcello Di Valentino,Simone Piazzalonga,Andreas Hoffmann
Rehabilitation Research and Practice , 2010, DOI: 10.1155/2010/823060
Abstract: Background. The aim of this study was to assess sexual function before and after cardiac rehabilitation in relation to medical variables. Methods. Analysis of patients participating in a 12-week exercise-based outpatient cardiac rehabilitation program (OCR) between April 1999 and December 2007. Exercise capacity (ExC) and quality of life including sexual function were assessed before and after OCR. Results. Complete data were available in 896 male patients. No sexual activity at all was indicated by 23.1% at baseline and 21.8% after OCR, no problems with sexual activity by 40.8% at baseline and 38.6% after OCR. Patients showed an increase in specific problems (erectile dysfunction and lack of orgasm) from 18% to 23% (<.0001) during OCR. We found the following independent positive and negative predictors of sexual problems after OCR: hyperlipidemia, age, CABG, baseline ExC and improvement of ExC, subjective physical and mental capacity, and sense of affiliation. Conclusions. Sexual dysfunction is present in over half of the patients undergoing OCR with no overall improvement during OCR. Age, CABG, low exercise capacity are independent predictors of sexual dysfunction after OCR.
PSSA-2, a Membrane-Spanning Phosphoprotein of Trypanosoma brucei, Is Required for Efficient Maturation of Infection
Cristina M. Fragoso, Gabriela Schumann Burkard, Michael Oberle, Christina Kunz Renggli, Karen Hilzinger, Isabel Roditi
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0007074
Abstract: The coat of Trypanosoma brucei consists mainly of glycosylphosphatidylinositol-anchored proteins that are present in several million copies and are characteristic of defined stages of the life cycle. While these major components of the coats of bloodstream forms and procyclic (insect midgut) forms are well characterised, very little is known about less abundant stage-regulated surface proteins and their roles in infection and transmission. By creating epitope-tagged versions of procyclic-specific surface antigen 2 (PSSA-2) we demonstrated that it is a membrane-spanning protein that is expressed by several different life cycle stages in tsetse flies, but not by parasites in the mammalian bloodstream. In common with other membrane-spanning proteins in T. brucei, PSSA-2 requires its cytoplasmic domain in order to exit the endoplasmic reticulum. Correct localisation of PSSA-2 requires phosphorylation of a cytoplasmic threonine residue (T305), a modification that depends on the presence of TbMAPK4. Mutation of T305 to alanine (T305A) has no effect on the localisation of the protein in cells that express wild type PSSA-2. In contrast, this protein is largely intracellular when expressed in a null mutant background. A variant with a T305D mutation gives strong surface expression in both the wild type and null mutant, but slows growth of the cells, suggesting that it may function as a dominant negative mutant. The PSSA-2 null mutant exhibits no perceptible phenotype in culture and is fully competent at establishing midgut infections in tsetse, but is defective in colonising the salivary glands and the production of infectious metacyclic forms. Given the protein's structure and the effects of mutation of T305 on proliferation and localisation, we postulate that PSSA-2 might sense and transmit signals that contribute to the parasite's decision to divide, differentiate or migrate.
The effect of the buffer layer coupling on the lattice parameter of epitaxial graphene on SiC(0001)
Timo Schumann,Martin Dubslaff,Myriano H. Oliveira Jr.,Michael Hanke,J. Marcelo J. Lopes,Henning Riechert
Physics , 2014, DOI: 10.1103/PhysRevB.90.041403
Abstract: Grazing incidence X-ray diffraction (GID) was employed to probe the structure of atomically thin carbon layers on SiC(0001): a so-called buffer layer (BL) with a $6(\sqrt{3}\times\sqrt{3})$R30$^\circ$ periodicity, a monolayer graphene (MLG) on top of the BL, and a bilayer graphene (BLG). The GID analysis was complemented by Raman spectroscopy. The lattice parameter of each layer was measured with high precision by GID. The BL possesses a different lattice parameter and corrugation when it is uncovered or beneath MLG. Our results demonstrate that the interfacial BL is the main responsible for the strain in MLG. By promoting its decoupling from the substrate via intercalation, it turns into graphene, leading to a simultaneous relaxation of the MLG and formation of a quasi-free-standing BLG.
A contrail cirrus prediction model
U. Schumann
Geoscientific Model Development (GMD) & Discussions (GMDD) , 2012, DOI: 10.5194/gmd-5-543-2012
Abstract: A new model to simulate and predict the properties of a large ensemble of contrails as a function of given air traffic and meteorology is described. The model is designed for approximate prediction of contrail cirrus cover and analysis of contrail climate impact, e.g. within aviation system optimization processes. The model simulates the full contrail life-cycle. Contrail segments form between waypoints of individual aircraft tracks in sufficiently cold and humid air masses. The initial contrail properties depend on the aircraft. The advection and evolution of the contrails is followed with a Lagrangian Gaussian plume model. Mixing and bulk cloud processes are treated quasi analytically or with an effective numerical scheme. Contrails disappear when the bulk ice content is sublimating or precipitating. The model has been implemented in a "Contrail Cirrus Prediction Tool" (CoCiP). This paper describes the model assumptions, the equations for individual contrails, and the analysis-method for contrail-cirrus cover derived from the optical depth of the ensemble of contrails and background cirrus. The model has been applied for a case study and compared to the results of other models and in-situ contrail measurements. The simple model reproduces a considerable part of observed contrail properties. Mid-aged contrails provide the largest contributions to the product of optical depth and contrail width, important for climate impact.
Lifestyle of Open Access
Karen Schumann
Libreas : Library Ideas , 2008,
Abstract:
Real-time Animation Scripts for Google Earth
Lars Schumann
Solstice : Electronic Journal of Geography and Mathematics , 2008,
Abstract:
A contrail cirrus prediction model
U. Schumann
Geoscientific Model Development Discussions , 2011, DOI: 10.5194/gmdd-4-3185-2011
Abstract: A new model to simulate and predict the properties of a large ensemble of contrails as a function of given air traffic and meteorology is described. The model is designed for approximate prediction of contrail cirrus cover and analysis of contrail climate impact, e.g. within aviation system optimization processes. The model simulates the full contrail life-cycle. Contrail segments form between waypoints of individual aircraft tracks in sufficiently cold and humid air masses. The initial contrail properties depend on the aircraft. The advection and evolution of the contrails is followed with a Lagrangian Gaussian plume model. Mixing and bulk cloud processes are treated quasi analytically or with an effective numerical scheme. Contrails disappear when the bulk ice content is sublimating or precipitating. The model has been implemented in a "Contrail Cirrus Prediction Tool" (CoCiP). This paper describes the model assumptions, the equations for individual contrails, and the analysis-method for contrail-cirrus cover derived from the optical depth of the ensemble of contrails and background cirrus. The model has been applied for a case study and compared to the results of other models and in-situ contrail measurements. The simple model reproduces a considerable part of observed contrail properties. Mid-aged contrails provide the largest contributions to the product of optical depth and contrail width, important for climate impact.
On the effect of emissions from aircraft engines on the state of the atmosphere
U. Schumann
Annales Geophysicae (ANGEO) , 2003,
Abstract: Emissions from aircraft engines include carbon dioxide, water vapour, nitrogen oxides, sulphur components and various other gases and particles. Such emissions from high-flying global civil subsonic air traffic may cause anthropogenic climate changes by an increase of ozone and cloudiness in the upper troposphere, and by an enhanced greenhouse effect. The absolute emissions by air traffic are small (a few percent of the total) compared to surface emissions. However, the greenhouse effect of emitted water and of nitrogen oxides at cruise altitude is potentially large compared to that of the same emissions near the earth's surface because of relatively large residence times at flight altitudes, low background concentrations, low temperature, and large radiative efficiency. Model computations indicate that emission of nitrogen oxides has doubled the background concentration in the upper troposphere between 40°N and 60°N. Models also indicate that this causes an increase of ozone by about 5-20%. Regionally, the observed annual mean change in cloudiness is 0.4%. It is estimated that the resultant greenhouse effect of changes in ozone and thin cirrus cloud cover causes a climatic surface temperature change of 0.01-0.1 K. These temperature changes are small compared to the natural variability. Recent research indicates that the emissions at cruise altitude may increase the amount of stratospheric aerosols and polar stratospheric clouds and thereby have an impact on the atmospheric environment. Air traffic is increasing about 5-6% per year, fuel consumption by about 3%, hence the effects of the related emissions are expected to grow. This paper surveys the state of knowledge and describes several results from recent and ongoing research.
Gawan MacDowell über Figurenrede in Wolframs Parzival und in Joyces Ulysses
Martin Schumann
Nordlit : Tidsskrift i litteratur og kultur , 2009,
Abstract:
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