644 research outputs found
Persönlichkeitsrechtsschutz im gegenwĂ€rtigen und zukĂŒnftigen deutschen internationalen Privatrecht
The Infrared Behavior of Gluon and Ghost Propagators in Landau Gauge QCD
A solvable systematic truncation scheme for the Dyson-Schwinger equations of
Euclidean QCD in Landau gauge is presented. It implements the Slavnov-Taylor
identities for the three-gluon and ghost-gluon vertices, whereas irreducible
four-gluon couplings as well as the gluon-ghost and ghost-ghost scattering
kernels are neglected. The infrared behavior of gluon and ghost propagators is
obtained analytically: The gluon propagator vanishes for small spacelike
momenta whereas the ghost propagator diverges stronger than a massless particle
pole. The numerical solutions are compared with recent lattice data for these
propagators. The running coupling of the renormalization scheme approaches a
fixed point, , in the infrared.Comment: 4 pages, 2 figures, Revtex; revised version accepted for publication
in Physical Review Letter
Slavnov-Taylor identities in Coulomb gauge Yang-Mills theory
The Slavnov-Taylor identities of Coulomb gauge Yang-Mills theory are derived
from the (standard, second order) functional formalism. It is shown how these
identities form closed sets from which one can in principle fully determine the
Green's functions involving the temporal component of the gauge field without
approximation, given appropriate input.Comment: 20 pages, no figure
Fermi-edge singularities in linear and non-linear ultrafast spectroscopy
We discuss Fermi-edge singularity effects on the linear and nonlinear
transient response of an electron gas in a doped semiconductor. We use a
bosonization scheme to describe the low energy excitations, which allows to
compute the time and temperature dependence of the response functions. Coherent
control of the energy absorption at resonance is analyzed in the linear regime.
It is shown that a phase-shift appears in the coherent control oscillations,
which is not present in the excitonic case. The nonlinear response is
calculated analytically and used to predict that four wave-mixing experiments
would present a Fermi-edge singularity when the exciting energy is varied. A
new dephasing mechanism is predicted in doped samples that depends linearly on
temperature and is produced by the low-energy bosonic excitations in the
conduction band.Comment: long version; 9 pages, 4 figure
Exclusive generation of rat spermatozoa in sterile mice utilizing blastocyst complementation with pluripotent stem cells
Blastocyst complementation denotes a technique that aims to generate organs, tissues, or cell types in animal chimeras via injection of pluripotent stem cells (PSCs) into genetically compromised blastocyst-stage embryos. Here, we report on successful complementation of the male germline in adult chimeras following injection of mouse or rat PSCs into mouse blastocysts carrying a mutation in Tsc22d3, an essential gene for spermatozoa production. Injection of mouse PSCs into Tsc22d3-Knockout (KO) blastocysts gave rise to intraspecies chimeras exclusively embodying PSC-derived functional spermatozoa. In addition, injection of rat embryonic stem cells (rESCs) into Tsc22d3-KO embryos produced interspecies mouse-rat chimeras solely harboring rat spermatids and spermatozoa capable of fertilizing oocytes. Furthermore, using single-cell RNA sequencing, we deconstructed rat spermatogenesis occurring in a mouse-rat chimera testis. Collectively, this study details a method for exclusive xenogeneic germ cell production in vivo, with implications that may extend to rat transgenesis, or endangered animal species conservation efforts.
Keywords: Blastocyst complementation; artificial reproductive technology; germ cell production; interspecies chimerism; pluripotency; sterility
Influence of measurement on the life-time and the line-width of unstable systems
We investigate the quantum Zeno effect in the case of electron tunneling out
of a quantum dot in the presence of continuous monitoring by a detector. It is
shown that the Schr\"odinger equation for the whole system can be reduced to
Bloch-type rate equations describing the combined time-development of the
detector and the measured system. Using these equations we find that continuous
measurement of the unstable system does not affect its exponential decay to a
reservoir with a constant density of states. The width of the energy
distribution of the tunneling electron, however, is not equal to the inverse
life-time -- it increases due to the decoherence generated by the detector. We
extend the analysis to the case of a reservoir described by an energy dependent
density of states, and we show that continuous measurement of such quantum
systems affects both the exponential decay rate and the energy distribution.
The decay does not always slow down, but might be accelerated. The energy
distribution of the tunneling electron may reveal the lines invisible before
the measurement.Comment: 13 pages, 8 figures, comments and references added; to appear in
Phys. Rev.
Quantum Experimental Data in Psychology and Economics
We prove a theorem which shows that a collection of experimental data of
probabilistic weights related to decisions with respect to situations and their
disjunction cannot be modeled within a classical probabilistic weight structure
in case the experimental data contain the effect referred to as the
'disjunction effect' in psychology. We identify different experimental
situations in psychology, more specifically in concept theory and in decision
theory, and in economics (namely situations where Savage's Sure-Thing Principle
is violated) where the disjunction effect appears and we point out the common
nature of the effect. We analyze how our theorem constitutes a no-go theorem
for classical probabilistic weight structures for common experimental data when
the disjunction effect is affecting the values of these data. We put forward a
simple geometric criterion that reveals the non classicality of the considered
probabilistic weights and we illustrate our geometrical criterion by means of
experimentally measured membership weights of items with respect to pairs of
concepts and their disjunctions. The violation of the classical probabilistic
weight structure is very analogous to the violation of the well-known Bell
inequalities studied in quantum mechanics. The no-go theorem we prove in the
present article with respect to the collection of experimental data we consider
has a status analogous to the well known no-go theorems for hidden variable
theories in quantum mechanics with respect to experimental data obtained in
quantum laboratories. For this reason our analysis puts forward a strong
argument in favor of the validity of using a quantum formalism for modeling the
considered psychological experimental data as considered in this paper.Comment: 15 pages, 4 figure
On the abundance of non-cometary HCN on Jupiter
Using one-dimensional thermochemical/photochemical kinetics and transport
models, we examine the chemistry of nitrogen-bearing species in the Jovian
troposphere in an attempt to explain the low observational upper limit for HCN.
We track the dominant mechanisms for interconversion of N2-NH3 and HCN-NH3 in
the deep, hightemperature troposphere and predict the rate-limiting step for
the quenching of HCN at cooler tropospheric altitudes. Consistent with other
investigations that were based solely on time-scale arguments, our models
suggest that transport-induced quenching of thermochemically derived HCN leads
to very small predicted mole fractions of hydrogen cyanide in Jupiter's upper
troposphere. By the same token, photochemical production of HCN is ineffective
in Jupiter's troposphere: CH4-NH3 coupling is inhibited by the physical
separation of the CH4 photolysis region in the upper stratosphere from the NH3
photolysis and condensation region in the troposphere, and C2H2-NH3 coupling is
inhibited by the low tropospheric abundance of C2H2. The upper limits from
infrared and submillimeter observations can be used to place constraints on the
production of HCN and other species from lightning and thundershock sources.Comment: 56 pages, 0 tables, 6 figures. Submitted to Faraday Discussions [in
press
A Russian Radical Conservative Challenge to the Liberal Global Order: Aleksandr Dugin
The chapter examines Russian political theorist Aleksandr Duginâs (b. 1962) challenge to the Western liberal order. Even though Duginâs project is in many ways a theoretical epitome of Russiaâs contemporary attempt to profile itself as a regional great power with a political and cultural identity distinct from the liberal West, Dugin can also be read in a wider context as one of the currently most prominent representatives of the culturally and intellectually oriented international New Right. The chapter introduces Duginâs role on the Russian right-wing political scene and his international networks, Russian neo-Eurasianism as his ideological footing, and his more recent âfourth political theoryâ as an attempt to formulate a new ideological alternative to liberalism as well as the two other main twentieth-century ideologies, communism and fascism. Duginâs fourth ideology, essentially meant as an alternative to a unipolar postâCold War global hegemony of victorious liberalism, draws inspiration from the German conservative revolutionary movement of the Weimar era. In particular, Martin Heideggerâs philosophy of history, with its thesis of the end of modernity and another beginning of Western thought, and Carl Schmittâs pluralistic model of geopolitics are highlighted as key elements of Duginâs eclectic political thought, which is most appropriately characterized as a form of radical conservatism
Echocardiographic AV-interval optimization in patients with reduced left ventricular function
BACKGROUND: Ritter's method is a tool used to optimize AV delay in DDD pacemaker patients with normal left ventricular function only. The goal of our study was to evaluate Ritter's method in AV delay-interval optimization in patients with reduced left ventricular function. METHODS: Patients with implanted DDD pacemakers and AVB III° were assigned to one of two groups according to ejection fraction (EF): Group 1 (EF > 35%) and Group 2 (EF < 35%). AV delay optimization was performed by means of radionuclide ventriculography (RNV) and application of Ritter's method. RESULTS: For each of the patients examined, we succeeded in defining an optimal AV interval by means of both RNV and Ritter's method. The optimal AV delay determined by RNV correlated well with the delay found by Ritter's method, especially among those patients with reduced EF. The intra-class correlation coefficient was 0.8965 in Group 1 and 0.9228 in Group 2. The optimal AV interval in Group 1 was 190 ± 28.5 ms, and 180 ± 35 ms in Group 2. CONCLUSION: Ritter's method is also effective for optimization of AV intervals among patients with reduced left ventricular function (EF < 35%). The results obtained by RNV correlate well with those from Ritter's method. Individual programming of the AV interval is fundamentally essential in all cases
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