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.

High-pressure thermodynamic Gibbs functions of ice and sea ice

Abstract: A new Gibbs thermodynamic potential function of ice Ih is proposed to extend and improve already existing ones and to unify various data and formulas for thermodynamic equilibrium properties of natural ice in a consistent manner. It is valid for absolute pressures from 0 to 211 MPa and for temperatures from 0 to 273.16 K. It is consistent with the current 1995 international scientific pure water standard, IAPWS-95, and with the latest 2003 Gibbs potential of seawater. In conjunction with the latter, it provides freezing temperatures of seawater for pressures up to 100 MPa (10,000 dbar). The potential functions of ice and seawater, if combined into a thermodynamic potential function of sea ice, provide all its thermodynamic equilibrium properties over the entire ‘Neptunian’ ranges of pressures and temperatures and brine practical salinities up to 42 (up to 50 at the surface). The new potential function of ice is compiled from an extended set of 26 groups with 339 experimental data points. It obeys the theoretical cubic law of Debye for low-temperature heat capacity, and pressure independence of zero-point entropy. Using the statistically derived residual entropy of Pauling, a physically well-grounded value for the entropy of liquid water at the triple point is provided. The severe 100% compressibility uncertainty of ice, present in former versions of the Gibbs potential, could be reduced to only 1% at normal pressure using various data on elastic lattice constants. The very high accuracy of the Clausius-Clapeyron coefficient at normal pressure of this formulation, which is 100 times more accurate than that of the 1994 international equation for the melting pressure, permits a precise determination of the normal melting temperature to be 273.152 518 K 2 K. On the other hand, users of the new function should be cautioned that some of the background data have been obtained from specimens of uncertain purity and crystalline perfection. The potential function is expressed in the 1990 International Temperature Scale ITS-90.

Measurements of top-quark pair spin correlations in the eμ channel at s√=13 TeV using pp collisions in the ATLAS detector

Abstract: A measurement of observables sensitive to spin correlations in tt¯ production is presented, using 36.1 fb - 1 of pp collision data at s=13 TeV recorded with the ATLAS detector at the Large Hadron Collider. Differential cross-sections are measured in events with exactly one electron and one muon with opposite-sign electric charge as a function of the azimuthal opening angle and the absolute difference in pseudorapidity between the electron and muon candidates in the laboratory frame. The azimuthal opening angle is also measured as a function of the invariant mass of the tt¯ system. The measured differential cross-sections are compared to predictions by several NLO Monte Carlo generators and fixed-order calculations. The observed degree of spin correlation is somewhat higher than predicted by the generators used. The data are consistent with the prediction of one of the fixed-order calculations at NLO, but agree less well with higher-order predictions. Using these leptonic observables, a search is performed for pair production of supersymmetric top squarks decaying into Standard Model top quarks and light neutralinos. Top squark masses between 170 and 230 GeV are largely excluded at the 95% confidence level for kinematically allowed values of the neutralino mass.

Measurement of B(t --> Wb)/B(t--> Wq) at the collider detector at fermilab.

Abstract: We present a measurement of the ratio of top-quark branching fractions R = B(t --> Wb)/B(t --> Wq), where q can be a b, s, or a d quark, using lepton-plus-jets and dilepton data sets with an integrated luminosity of approximately 162 pb(-1) collected with the Collider Detector at Fermilab during Run II of the Tevatron. The measurement is derived from the relative numbers of tt events with different multiplicity of identified secondary vertices. We set a lower limit of R > 0.61 at 95% confidence level.

Essentialist theory of ‘hybrids’: From animal kinds to ethnic categories and race

Abstract: This article presents a theory of the perception of hybrids, resulting from cross-breeding natural animals that pertain to different species and of children parented by couples with a mixed ethnic or racial background. The theory states that natural living beings, including humans, are perceived as possessing a deeply ingrained characteristic that is called ‘essence’ or ‘blood’ or ‘genes’ in everyday discourse and that uniquely determines their category membership. If, by whatever means, the genes or essences of two animals of different species are combined in a hybrid, the two incompatible essences collapse, leaving the hybrid in a state of non-identity and non-belonging. People despise this state and reject the hybrid (Study 1). This devaluation effect holds with cross-kind hybrids and with hybrids that arise from genetically combining animals from incompatible habitats across three cultures: Austria, India and Japan (Study 2). In the social world, groups and ethnic or racial categories frequently are essentialized in an analogue way. When people with an essentialist mindset judge ethnically or racially mixed offspring, they perceive a collapse of ethnic or racial essence and, consequently, denigrate these children, as compared to children from ‘pure’ in-group or out-group parents (Study 3). The findings are discussed in terms of the widespread ‘yuck factor’ against genetically modified animals, in terms of the cultural concepts of monstrosity and of racism and prejudice.

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。