[en] In the present paper the author is concerned with 2D quantum gravity in the conformal gauge. The basic work of David and Distler and Kawai is only used as a guideline, which in particularly provides us with the correct result. He quantizes a special system consisting of a Majorana fermion moving on a 2D surface with the topology of a torus. The system is partially solved by deriving the anomalous scaling dimension of the fermion propagator. The scaling behavior is self-induced, i.e. he needs not to introduce a conformal field theory coupling to independently generated quantum gravity. A rather conventional perturbation theoretic procedure is developed, which links 2D quantum gravity with more traditional quantum field theories

[en] Exposed plasma membrane proteins were labeled with ¹²⁵I before and after incubation of boar sperm under capacitating conditions. Labeled protein profiles were compared to the ability of the sperm to penetrate zona-free hamster ova. Quantitatively, the labeled sperm membrane proteins were primarily low Mr prior to capacitation. The majority of the labeled seminal plasma protein was also low Mr. After capacitation, two new proteins (64,000 Mr and 78,000 Mr) were labeled. Sperm did not exhibit these exposed membrane proteins when incubated under noncapacitating conditions. Appearance of these proteins was not correlated to the percentage of acrosome-reacted sperm. Although the 64,000 Mr protein was not consistently observed, the relative labeling of the 78,000 Mr protein was highly correlated with the ability of sperm to fuse with zona-free hamster ova. The 78,000 Mr protein may be a sperm protein involved in fusion with the egg plasma membrane

[en] Thermoluminescence (TL) dating was applied for artefacts found near the small village of Michelstetten, Lower Austria. Settlements in this region can be traced back a long time and, according to archaeologists, the artefacts discovered may be as old as 6000 years. A modified sample preparation technique based on the fine-grain method was developed. This technique results in a higher reproducibility and reduces the overall preparation time. For some artefacts the new information of the TL dating leads to an unforeseen re-interpretation of the archaeological age. Furthermore, an iron furnace from the period of the Roman Empire could be dated. For the first time, it was possible to estimate correctly the point of time of the burn-down of an ancient wooden house via an analysis of the house's clay plaster. The fire took place in the sixth century; this was confirmed by dating the ceramic artefacts. (author)

[en] Due to the pronounced energy dependence of the neutron quality factor, accurate assessment of the biologically relevant dose requires knowledge of the spectral neutron fluence rate. Bonner sphere spectrometers are the only instruments which provide a sufficient response over practically the whole energy range of the cosmic ray induced neutron component. Measurements in a 62 MeV proton beam at Paul Scherrer Institute, Switzerland, and in the CERN-EU high-energy reference field led to the assumption that conventional active devices for the detection of thermal neutrons inside the BSS, e.g. ⁶LiI(Eu) scintillators, also respond to charged particles when used in high-energy mixed radiation fields. The effects of these particles cannot be suppressed by amplitude discrimination and are subsequently misinterpreted as neutron radiation. In contrast, paired TLD-600 and TLD-700 thermoluminescence dosemeters allow the determination of a net thermal neutron signal. (author)

[en] An effective chiral Lagrangian for the π-ρ-A₁-system is used to study the decay τ^± → ν_τπ⁺π^-π^±. Demanding that the hadronic current <0vertical strokeJ_μvertical stroke3π> agrees at the low energy limit with the one obtained from the corresponding pseudoscalar meson Lagrangian L(π), an ambiguity linked to free parameters in L(π,ρ,A₁) is eliminated. The decay spectrum and branching ratio of τ^± → ν_τπ⁺π^-π^± are calculated as functions of the A₁-mass and compared with the experimental results. So conclusions can be drawn concerning the A₁-parameters, which are found to be m_A1 = (1180±50) MeV; Γ_A1 = (450±100) MeV. The mass-value is smaller than recently published ones. This is attributed to the effect of suppressed decay channels not seen in the experiments up to now. A contribution from direct, non-(ρ⁰π^±) resonance A₁-decay is obtained, being about 15%. (orig.)

[en] The fermion in the gauge invariant formulation of the chiral Schwinger model and its relation to the fermion in the anomalous formulation is studied. A gauge invariant fermion operator is constructed that does not give rise to an asymptotic fermion field. It fits in the scheme prepared by generalized Schwinger models. Singularities in the short-distance limit of the chiral Schwinger model in the anomalous formulation lead to the conclusion that it is not a promising starting point for investigations towards realistic (3+1)-dimensional gauge theories with chiral fermion content. A new anomalous (1+1)-dimensional model is studied, the chiral quantum gravity. It is proven to be consistent if only a limited number of chiral fermions couple. The fermion propagator behaves analogously to the one in the massless Thirring model. A general rule is derived for the change of the fermion operator, which is induced by the breakdown of a gauge symmetry. (orig.)

[en] The chiral Schwinger model's fermionic sector is studied by comparing the fermion propagator of the original Jackiw-Rajaraman formulation with a propagator in the gauge invariant formulation. The main difference consists in the existence of fermionic single particle states in the original formulation, while there are no such states in the gauge invariant formulation. It is suggested that this difference is caused by renormalization, which changes the Hilbert space. (orig.)

[en] Fermionic propagators and the Wilson loop of the gauge invariant chiral Schwinger model are compared with their counterparts in the Schwinger model. In this paper it is made evident that in the chiral Schwinger model the charges are also shielded as in the ordinary Schwinger model. Furthermore we show that the Schwinger model can be reformulated in such a way that it becomes the chiral Schwinger model endowed with a special regularization scheme

[en] Two theories of chiral fermions coupled to different quantum gravities in two dimensions are studied. One employs Jackiw's ansatz for classical gravity by introducing an auxiliary scalar, the other is based on the induced quantum gravity of Polyakov, which has no classical analogue. By investigating a localized theory of the effective action we show that in both cases a limited number of fermions of either chirality may couple consistently. It is stressed that the Weyl variable has to be quantized properly, which is related to recent work done on non-critical strings. (orig.)

[en] The European Council directive 96/29/Euratom requires dosimetric precautions if the effective dose exceeds 1 mSv/a. On an average, this value is exceeded by aircrew members. Roughly half of the radiation exposure at flight altitudes is caused by cosmic ray-induced neutrons. Active (⁶LiI(Eu)-scintillator) and passive (TLDs) Bonner sphere spectrometers were used to determine the neutron energy spectra atop Mt. Sonnblick (3105 m) and Mt. Kitzsteinhorn (3029 m). Further measurements in a mixed radiation field at CERN as well as in a proton beam of 62 MeV at Paul Scherrer Institute, Switzerland, confirmed that not only neutrons but also charged particles contribute to the readings of active detectors, whereas TLD-600 and TLD-700 in pair allow the determination of the thermal neutron flux. Unfolding of the detector data obtained atop both mountains shows two relative maxima around 1 MeV and 85 MeV, which have to be considered for the assessment of the biologically relevant dose equivalent. By convoluting the spectra with appropriate conversion functions the neutron dose equivalent rate was determined to be 150±15 nSv/h. The total dose equivalent rate determined by the HTR-method was 210±15 nSv/h. The results are in good agreement with LET-spectrometer and Sievert counter measurements carried out simultaneously