Despite an increasing research interest in subject-specific teacher knowledge, the scientific understanding regarding teachers’ professional knowledge for teaching English as a foreign language (TEFL) is very limited. This study therefore applies standardized tests to directly assess content knowledge (CK), pedagogical content knowledge (PCK), and general pedagogical knowledge (GPK) of preservice teachers for TEFL in Germany from different programs and stages during initial teacher education (during their master’s studies at university and at the end of their induction phase). Structural analysis provides evidence that teacher knowledge with respect to TEFL is a multidimensional construct and PCK is closely related to both CK and GPK. Test scores vary across preservice teachers from different programs and stages, which adequately reflects differences in the learning opportunities they had during teacher education.

It is generally assumed that verbal inflections in early 12 acquisition primarily mark lexical aspect inherent in the verb or predicate with tense distinctions being neglected (=the aspect hypothesis). 1 This paper gives a brief account of the L2 acquisition of verbal inflections by two German children learning English without formal instruction. The results of the study are discussed in connection with the aspect hypothesis. They support the affiliation of verbal inflections with lexical aspect; however, contrary to the predictions, it is shown that the -ING inflection is not associated mainly with activity verbs but also with a relatively high proportion of achievement verbs. This is accounted for by the fact that the children use the progressive form with future reference. It is argued that although lexical aspect seems to grant the learnability of verbal inflections in early L2 acquisition, tense is not defective, as implied in the aspect hypothesis.

Strongly nonlinear relaxation oscillations of discharge current and plasma potential are investigated in a magnetized thermionic plasma discharge. The quasi-one-dimensional electron motion allows a direct comparison with one-dimensional models and computer simulations. Two different stable discharge modes can be established, the low-current space charge limited and the high-current temperature limited mode. Time resolved probe measurements of the plasma potential distribution demonstrate that the current oscillations result from a strongly nonlinear instability of the potential structure in the weak current discharge mode. This confirms the model based on particle-in-cell simulations [F. Greiner et al., Phys. Plasmas 2, 1810 (1995)]. The oscillation process consists of three distinct phases. The sequence of events and the observed parameter dependencies of the oscillation frequency is in accordance with the model. The periodically driven system shows the characteristic behavior of nonlinear oscillators: quasiperiodicity, mode-locking, and period doubling sequences towards chaos. It is possible to link the complex dynamical behavior to the details of the trigger mechanism that are revealed by the simulation.

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