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Es ist nicht üblich, Brecht und Celan in einem Atemzug zu nennen. Zu sehr dominiert die Vorstellung von dem hermetischen Lyriker hier, der eher mit Hölderlin, Mallarmé und Rilke in Zusammenhang gebracht wird und sich in der raffinierten und weltabgewandten Verschlüsselung ausgedrückt haben soll, und dem operativen Dichter dort, der, um in das politische Handgemenge unmittelbar eingreifen zu können und dort seine Wirkungen zu erzielen, sich einer möglichst kommunikativen und transparenten Sprache verschrieb. Woher sollten sich dann ihre Sphären je berühren? Indes, sie berühren sich, und nicht zuletzt dadurch, dass Celan selber noch in seiner letzten und zunehmend umdüsterten Lebensphase sich wiederholt und ausdrücklich auf Brecht bezogen hat.
"Auf eine unüberschreitbare Grenze gestoßen / Hast du, so heißt es / Eine überschreitbare überschritten." Diese Zeilen aus Brechts Gedicht auf den gescheiterten Grenzübergang Walter Benjamins 1940 in den Pyrenäen könnten dann auch, wenn auch bei radikal verändertem Vorzeichen, als Motto über dem ganzen Schaffen des Autors und Grenzgängers Volker Braun stehen. Denn auch sein ersehnter 'Übergang' drohte zu scheitern - und ist dann schließlich auch gescheitert - bei dem Zusammenstoß mit schier unüberwindlichen Hürden, auch hier solche, wie es sich herausstellte, der Macht, also ebenfalls bürokratisch-politischer Art; und auch Braun sah sich aufgefordert, bei der vergeblichen Suche nach dem einen, verwehrten Übergang dann auch alle anderen Möglichkeiten des Übergangs - die denkbaren wie die unausdenkbaren - auszutesten. Dabei ist der, wie es auf den ersten Blick scheinen könnte, wohl nächstliegende Übergang für einen Schriftsteller von Brauns Herkunft und politischer Überzeugung - der erhoffte in den Sozialismus - paradoxerweise gerade der, der sich dann als glatt undurchführbar erwies. Denn gemäß dem einstigen tschechischen Witz von den zwei Stadien in der Entwicklung des Sozialismus - die Schwierigkeiten der Entwicklung, und die Entwicklung der Schwierigkeiten - ist Brauns Werk also schon früh gezeichnet von der Blockade, die sich zwischen dem 'realen Sozialismus' und der Verwirklichung des Marxschen Emanzipationsprogramms auftat. So ist sein Werk wie kaum ein anderes reich an Übergängen, welcher Reichtum aber gleichzeitig die bald ausdrückliche, bald verborgene Klage und Elegie um einen einzigen verwehrten, verfehlten und gescheiterten Übergang darstellt: um jenen Übergang, in dem alle anderen hätten münden sollen, den Übergang in die von Marx evozierte menschliche Gemeinschaft.
The Born cross sections of the e+e− → D*+D*− and e+e− → D*+D− processes are measured using e+e− collision data collected with the BESIII experiment at center-of-mass energies from 4.085 to 4.600 GeV, corresponding to an integrated luminosity of 15.7 fb−1. The results are consistent with and more precise than the previous measurements by the Belle, Babar and CLEO collaborations. The measurements are essential for understanding the nature of vector charmonium and charmonium-like states.
We report a measurement of the observed cross sections of e+ e− → J/ψX based on 3.21 fb − 1 of data accumulated at energies from 3.645 to 3.891 GeV with the BESIII detector operated at the BEPCII collider. In analysis of the cross sections, we measured the decay branching fractions of B(ψ(3686) → J/ψX) = (64.4 ± 0.6 ± 1.6)% and B(ψ(3770) → J/ψX) = (0.5 ± 0.2 ± 0.1)% for the first time. The energy-dependent line shape of these cross sections cannot be well described by two Breit-Wigner (BW) amplitudes of the expected decays ψ (3686) → J/ψX and ψ(3770) → J/ψX. Instead, it can be better described with one more BW amplitude of the decay R(3760)→ J/ψX. Under this assumption, we extracted the R (3760) mass M R (3760 ) = 3766.2 ± 3.8 ± 0.4 MeV/c2, total width Γ tot R ( 3760 ) = 22.2 ± 5.9 ± 1.4 MeV, and product of leptonic width and decay branching fraction
ΓeeR(3760) B[R(3760) → J/ψX] = (79.4 ± 85.5 ± 11.7) eV. The significance of the R(3760) is 5.3σ. The first uncertainties of these measured quantities are from fits to the cross sections and second systematic.
Using a sample of (10.09±0.04)×109 J/ψ events collected with the BESIII detector, a partial wave analysis of J/ψ→γη′η′ is performed.The masses and widths of the observed resonances and their branching fractions are reported. The main contribution is from J/ψ→γf0(2020) with f0(2020)→η′η′, which is found with a significance of greater than 25σ. The product branching fraction B(J/ψ → γf0(2020))⋅B(f0(2020) → η′η′ is measured to be (2.63±0.06(stat.) + 0.31−0.46(syst.))×10−4.
We present the first experimental search for the rare charm decay D0→π0ν¯ν. It is based on an e+e− collision sample consisting of 10.6×10^6 pairs of D0¯D0 mesons collected by the BESIII detector at √s=3.773 GeV, corresponding to an integrated luminosity of 2.93 fb^−1. A data-driven method is used to ensure the reliability of the background modeling. No significant D0→π0ν¯ν signal is observed in data and an upper limit of the branching fraction is set to be 2.1×10^-4 at the 90% confidence level. This is the first experimental constraint on charmed-hadron decays into dineutrino final states.
Using data samples collected with the BESIII detector operating at the BEPCII storage ring at center-of-mass energies from 4.178 to 4.600 GeV, we study the process eþe− → π0Xð3872Þγ and search for Zcð4020Þ0 → Xð3872Þγ. We find no significant signal and set upper limits on σðeþe− → π0Xð3872ÞγÞ · BðXð3872Þ → πþπ−J=ψÞ and σðeþe− → π0Zcð4020Þ0Þ · BðZcð4020Þ0 → Xð3872ÞγÞ · BðXð3872Þ → πþπ−J=ψÞ for each energy point at 90% confidence level, which is of the order of several tenths pb.
We measure the inclusive semielectronic decay branching fraction of the D+s meson. A double-tag technique is applied to e+e− annihilation data collected by the BESIII experiment at the BEPCII collider, operating in the center-of-mass energy range 4.178–4.230 GeV. We select positrons fromD+s→Xe+νe with momenta greater than 200 MeV/c and determine the laboratory momentum spectrum, accounting for the effects of detector efficiency and resolution. The total positron yield and semielectronic branching fraction are determined by extrapolating this spectrum below the momentum cutoff. We measure the D+s semielectronic branching fraction to be(6.30±0.13(stat.)±0.09(syst.)±0.04(ext.))%, showing no evidence for unobserved exclusive semielectronic modes. We combine this result with external data taken from literature to determine the ratio of the D+s and D0 semielectronic widths, Γ(D+s→Xe+νe)Γ(D0→Xe+νe)=0.790±0.016(stat.)±0.011(syst.)±0.016(ext.). Our results are consistent with and more precise than previous measurements.
Encouraging clinical results were reported on a novel cone-in-cone coupling for the fixation of dental implant-supported crowns (Acuris, Dentsply Sirona Implants, Mölndal, Sweden). However, the presence or absence of a microgap and a potential bacterial leakage at the conometric joint has not yet been investigated. A misfit and a resulting gap between the conometric components could potentially serve as a bacterial reservoir that promotes plaque formation, which in turn may lead to inflammation of the peri-implant tissues. Thus, a two-fold study set-up was designed in order to evaluate the bidirectional translocation of bacteria along conometrically seated single crowns. On conometric abutments filled with a culture suspension of anaerobic bacteria, the corresponding titanium nitride-coated (TiN) caps were fixed by friction. Each system was sterilized and immersed in culture medium to provide an optimal environment for microbial growth. Positive and negative controls were prepared. Specimens were stored in an anaerobic workstation, and total and viable bacterial counts were determined. Every 48 h, samples were taken from the reaction tubes to inoculate blood agar plates and to isolate bacterial DNA for quantification using qrt-PCR. In addition, one Acuris test system was subjected to scanning electron microscopy (SEM) to evaluate the precision of fit of the conometric coupling and marginal crown opening. Throughout the observational period of one week, blood agar plates of the specimens showed no viable bacterial growth. qrt-PCR, likewise, yielded a result approaching zero with an amount of about 0.53 × 10−4 µg/mL DNA. While the luting gap/marginal opening between the TiN-cap and the ceramic crown was within the clinically acceptable range, the SEM analysis failed to identify a measurable microgap at the cone-in-cone junction. Within the limits of the in-vitro study it can be concluded that the Acuris conometric interface does not allow for bacterial translocation under non-dynamic loading conditions.