Wolfgang Wagner

Bio: Wolfgang Wagner is an academic researcher from Vienna University of Technology. The author has contributed to research in topics: Large Hadron Collider & Top quark. The author has an hindex of 156, co-authored 2342 publications receiving 123391 citations. Previous affiliations of Wolfgang Wagner include University of Pennsylvania & University of Amsterdam.

Measurement of bottom-quark hadron masses in exclusive J/ψ decays with the CDF detector

Abstract: We measure the masses of b hadrons in exclusively reconstructed final states containing a J/{psi}{yields}{mu}{sup -}{mu}{sup +} decay using 220 pb{sup -1} of data collected by the CDF II experiment. We find: m(B{sup +})=5279.10{+-}0.41{sub (stat.)}{+-}0.36{sub (sys.)} MeV/c{sup 2}, m(B{sup 0})=5279.63{+-}0.53{sub (stat.)}{+-}0.33{sub (sys.)} MeV/c{sup 2}, m(B{sub s}{sup 0})=5366.01{+-}0.73{sub (stat.)}{+-}0.33{sub (sys.)} MeV/c{sup 2}, m({lambda}{sub b}{sup 0})=5619.7{+-}1.2{sub (stat.)}{+-}1.2{sub (sys.)} MeV/c{sup 2}. m(B{sup +})-m(B{sup 0})=-0.53{+-}0.67{sub (stat.)}{+-}0.14{sub (sys.)} MeV/c{sup 2}, m(B{sub s}{sup 0})-m(B{sup 0})=86.38{+-}0.90{sub (stat.)}{+-}0.06{sub (sys.)} MeV/c{sup 2}, m({lambda}{sub b}{sup 0})-m(B{sup 0})=339.2{+-}1.4{sub (stat.)}{+-}0.1{sub (sys.)} MeV/c{sup 2}. The measurements of the B{sub s}{sup 0}, {lambda}{sub b}{sup 0} mass, m(B{sub s}{sup 0})-m(B{sup 0}) and m({lambda}{sub b}{sup 0})-m(B{sup 0}) mass difference are of better precision than the current world averages.

Senescence-associated DNA methylation is stochastically acquired in subpopulations of mesenchymal stem cells

Abstract: Summary Replicative senescence has a major impact on function and integrity of cell preparations This process is reflected by continuous DNA methylation (DNAm) changes at specific CpG dinucleotides in the course of in vitro culture, and such modifications can be used to estimate the state of cellular senescence for quality control of cell preparations Still, it is unclear how senescence-associated DNAm changes are regulated and whether they occur simultaneously across a cell population In this study, we analyzed global DNAm profiles of human mesenchymal stem cells (MSCs) and human umbilical vein endothelial cells (HUVECs) to demonstrate that senescence-associated DNAm changes are overall similar in these different cell types Subsequently, an Epigenetic-Senescence-Signature, based on six CpGs, was either analyzed by pyrosequencing or by bar-coded bisulfite amplicon sequencing There was a good correlation between predicted and real passage numbers in bulk populations of MSCs (R2 = 067) and HUVECs (R2 = 097) However, when we analyzed the Epigenetic-Senescence-Signature in subclones of MSCs, the predictions revealed high variation and they were not related to the adipogenic or osteogenic differentiation potential of the subclones Notably, in clonally derived subpopulations, the DNAm levels of neighboring CpGs differed extensively, indicating that these genomic regions are not synchronously modified during senescence Taken together, senescence-associated DNAm changes occur in a highly reproducible manner, but they are not synchronously co-regulated They rather appear to be acquired stochastically—potentially evoked by other epigenetic modifications

Growing stock estimation for alpine forests in Austria: a robust lidar-based approach

Abstract: The overall goal of this study was to describe a novel area-based semiempirical model for estimating growing stock from small-footprint light detection and ranging (lidar) data. The model assumes a linear relationship between growing stock and lidar-derived canopy volume that is stratified according to several canopy height classes to account for height dependent differences in canopy structure and nonlinear tree size-shape relationships. It was applied over a 128 km2 alpine area in Austria where operational forest inventory data and lidar data acquired in winter and summer were available. The analysis showed that the semiempirical model was quite robust against changes in laser point density and acquisition time. Further, it was found that the model performed as well as a widely used iterative regression method based on a multiplicative model. Both models reached a high coefficient of determination (R2 = 0.76–0.86) and a standard deviation of the residuals in the order of 20.4%–29.1%. Although it is less...

Search for a Charged Higgs Boson Produced in the Vector-boson Fusion Mode with Decay H ± →W ± Z using pp Collisions at √s=8 TeV with the ATLAS Experiment

Abstract: A search for a charged Higgs boson, H-+/-, decaying to a W-+/- boson and a Z boson is presented. The search is based on 20.3 fb(-1) of proton-proton collision data at a center-of-mass energy of 8 TeV recorded with the ATLAS detector at the LHC. The H-+/- boson is assumed to be produced via vector-boson fusion and the decays W-+/- -> q (q') over bar and Z -> e(+)e(-)/mu(+)mu(-) are considered. The search is performed in a range of charged Higgs boson masses from 200 to 1000 GeV. No evidence for the production of an H+ boson is observed. Upper limits of 31-1020 fb at 95% C.L. are placed on the cross section for vector-boson fusion production of an H-+/- boson times its branching fraction to W(+/-)Z. The limits are compared with predictions from the Georgi-Machacek Higgs triplet model.

A neural network clustering algorithm for the ATLAS silicon pixel detector

Abstract: A novel technique to identify and split clusters created by multiple charged particles in the ATLAS pixel detector using a set of artificial neural networks is presented. Such merged clusters are a common feature of tracks originating from highly energetic objects, such as jets. Neural networks are trained using Monte Carlo samples produced with a detailed detector simulation. This technique replaces the former clustering approach based on a connected component analysis and charge interpolation. The performance of the neural network splitting technique is quantified using data from proton-proton collisions at the LHC collected by the ATLAS detector in 2011 and from Monte Carlo simulations. This technique reduces the number of clusters shared between tracks in highly energetic jets by up to a factor of three. It also provides more precise position and error estimates of the clusters in both the transverse and longitudinal impact parameter resolution.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Fast parallel algorithms for short-range molecular dynamics

Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。