An empirical investigation of pronunciation problems of young learners of English as a foreign language - identification and remedial strategies

This thesis describes a novel pronunciation training programme devised for young learners of English as a foreign language in schools in Germany. The intervention is grounded in current theories of second language, employs valid and established pronunciation task formats, and targets a core set of significant pronunciation problem areas typical of young learners. This core set was identified from research literature, curricular requirements as well as data from questionnaires completed by 245 English language teachers in the German state of Hesse. The English pronunciation intervention was implemented over five months within the language education setting of English L2 learners (ages 10 to 12) in two schools in Frankfurt/Main. Quasi-experimental classroom research was conducted using a control group design to examine the effects of the pronunciation intervention. To obtain within-subject measurements, the data were collected at three points: prior to the intervention (pre-test), immediately after the intervention (post-test) and six months later (follow-up). There were two types of analyses of the pronunciation data. First there was auditory evaluation: all test utterances by the students were assessed auditorily using a three-point scale to rate their performance. Secondly, acoustic analysis of the same data was conducted using the computer software programme Praat. The acoustic parameters of interest included fundamental and formant frequencies, vowel and fricative durations, spectral peaks and spectral rate of change, to assess changes in pronunciation. The main aim of the analyses was to measure the impacts, if any, of the pronunciation intervention. The results revealed that maturation processes took place for both the intervention and control groups, as predicted. Overall, the auditory analysis presented mixed results but showed some training effects for the fricatives /ð/ and /θ/ and the affricate /dʒ/. Most salient of all, there were clear frequency effects. The acoustic data analysis indicated more systematic effects of the intervention on acoustic parameters associated with precision and stability. The scatter plots and Euclidean distances computed from the acoustic data revealed more precision and stability in the production of the vowels /ɑː, ɔː, ə, æ/, the diphthongs /ɪə; eɪ/ and the approximant /w/ in the intervention group. In addition, the centre of gravity values indicated that the training led to a more native-like production of /θ/ and /ð/

Structured outflow from a dynamo active accretion disc

We present an axisymmetric numerical model of a dynamo active accretion disc. If the dynamo-generated magnetic field in the disc is sufficiently strong (close to equipartition with thermal energy), a fast magneto-centrifugally driven outflow develops within a conical shell near the rotation axis, together with a slower pressure driven outflow from the outer parts of the disc as well as around the axis. Our results show that a dynamo active accretion disc can contribute to driving an outflow even without any external magnetic field. The fast outflow in the conical shell is confined by the azimuthal field which is produced by the dynamo in the disc and advected to the disc corona. This part of the outflow has high angular momentum and is cooler and less dense than its surroundings. The conical shell's half-opening angle is typically about 30 degrees near the disc and decreases slightly with height. The slow outflow is hotter and denser.Comment: 20 pages, 25 figures, accepted for publication in A&

Specific heat measurement and its application to Pd2[rare earth]In alloys

Some experimental details of the construction and programming of the equipment is presented and discussed. The calorimeter is used to determine the specific heat of solid, approximately 1 g samples within the temperature range 4 K to 210 K. Initially the performance of the calorimeter is demonstrated by measuring the specific heat of a spectroscopically pure copper sample. The working of the apparatus is demonstrated with the experimental investigation of the specific heat of some Pd2[rare earth]In alloys. The 4f-electron contribution to the specific heat of Pd2YbIn and Pd2HoIn is determined, by subtraction of isostructural Pd2LuIn from the measured specific heat of Pd2YbIn and Pd2HoIn

Stellar dynamo driven wind braking instead of disc coupling

Star-disc coupling is considered in numerical models where the stellar field is not an imposed perfect dipole, but instead a more irregular self-adjusting dynamo-generated field. Using axisymmetric simulations of the hydromagnetic mean-field equations, it is shown that the resulting stellar field configuration is more complex, but significantly better suited for driving a stellar wind. In agreement with recent findings by a number of people, star-disc coupling is less efficient in braking the star than previously thought. Moreover, stellar wind braking becomes equally important. In contrast to a perfect stellar dipole field, dynamo-generated stellar fields favor field-aligned accretion with considerably higher velocity at low latitudes, where the field is weaker and originating in the disc. Accretion is no longer nearly periodic (as it is in the case of a stellar dipole), but it is more irregular and episodic.Comment: 19 pages, 15 figures, some errors corrected, Astron. Nach. (submitted). For higher quality images, see http://www.nordita.dk/~brandenb/papers/stellardyn

The effects of vertical outflows on disk dynamos

We consider the effect of vertical outflows on the mean-field dynamo in a thin disk. These outflows could be due to winds or magnetic buoyancy. We analyse both two-dimensional finite-difference numerical solutions of the axisymmetric dynamo equations and a free-decay mode expansion using the thin-disk approximation. Contrary to expectations, a vertical velocity can enhance dynamo action, provided it is not too strong. In the nonlinear regime this can lead to super-exponential growth of the magnetic field.Comment: 14 pages, final version after referee comments, accepted in A&

Outflows from dynamo-active protostellar accretion discs

An axisymmetric model of a cool, dynamo-active accretion disc is applied to protostellar discs. Thermally and magnetically driven outflows develop that are not collimated within 0.1 AU. In the presence of a central magnetic field from the protostar, accretion onto the protostar is highly episodic, which is in agreement with earlier work.Comment: 8 pages, 9 figures, to be published in: Magnetic fields and star formation: theory versus observations, eds: A. I. Gomez de Castro et al., Kluwer Acad. Publ., Dordrec

Laboratory biomarkers associated to death in the first three COVID-19 waves in Portugal

Funding Information: This study is inserted in the project Predictive Models of COVID-19 Outcomes for Higher Risk Patients Towards a Precision Medicine (PREMO), supported by Fundação para Publisher Copyright: © 2023 IEEE.Besides the pandemic being over, new SARS-CoV-2 lineages, and sub-lineages, still pose risks to global health. Thus, in this preliminary study, to better understand the characteristics of COVID-19 patients and the effect of certain hematologic biomarkers on their outcome, we analyzed data from 337 patients admitted to the ICU of a single-center hospital in Lisbon, Portugal, in the first three waves of the pandemic. Most patients belonged to the second (40.4%) and third (41.2%) waves. The ones from the first wave were significantly older and relied more on respiratory techniques like invasive mechanic ventilation and extracorporeal membrane oxygenation. There were no significant differences between waves regarding mortality in the ICU. In general, non-survivors had worse laboratory results. Biomarkers significantly associated with death changed depending on the waves. Increased high-sensitivity cardiac troponin I results, and lower eosinophil counts were associated to death in all waves. In the second and third waves, the international normalized ratio, lymphocyte counts, and neutrophil counts were also associated to mortality. A higher risk of death was linked to increased myoglobin results in the first two waves, as well as increased creatine kinase results, and lower platelet counts in the third wave.publishersversionpublishe