The recognition of the prosodic focus position in German-learning infants from 4 to 14 months

The aim of the present study was to elucidate in a study with 4-, 6-, 8-, and 14-month-old German-learning children, when and how they may acquire the regularities which underlie Focus-to-Stress Alignment (FSA) in the target language, that is, how prosody is associated with specific communicative functions. Our findings suggest, that 14-month-olds have already found out that German allows for variable focus positions, after having gone through a development which goes from a predominantly prosodically driven processing of the input to a processing where prosody interacts more and more with the growing lexical and syntactic knowledge of the child

Butterfly hysteresis loop and dissipative spin reversal in the S=1/2, V15 molecular complex

Time resolved magnetization measurements have been performed on a spin 1/2 molecular complex, so called V$_{15}$. Despite the absence of a barrier, magnetic hysteresis is observed over a timescale of several seconds. A detailed analysis in terms of a dissipative two level model is given, in which fluctuations and splittings are of same energy. Spin-phonon coupling leads to long relaxation times and to a particular "butterfly" hysteresis loop.Comment: LaTeX/RevTeX, 3 figures.Approved for publication in PR

Die gepulste alternierende Anregung in der konfokalen Fluoreszenzspektroskopie

Die konfokale Fluoreszenzspektroskopie ermöglicht die Untersuchung der Struktur und Dynamik von Biomolekülen. In den letzten Jahren konnte sie sich zunemend im Bereich der Einzelmolekülspektroskopie etablieren, jedoch besteht gerade im Hinblick auf die zunehmende Zahl der in vivo-Anwendungen Potential, die Sensitivität und die Information, die aus einem einzelnen Datensatz herausgefiltert werden kann , zu erhöhen. In dieser Arbeit konnte die Methode der gepulsten alternierenden Anregung (Pulsed Interleaved Excitation, PIE) entwickelt werden, bei der die zusätzliche Information zugänglich ist, mit welcher Anregungsquelle das jeweilige Photon erzeugt wurde

Super-resolution microscopy reveals specific recruitment of HIV-1 envelope proteins to viral assembly sites dependent on the envelope C-terminal tail

The inner structural Gag proteins and the envelope (Env) glycoproteins of human immunodeficiency virus (HIV-1) traffic independently to the plasma membrane, where they assemble the nascent virion. HIV-1 carries a relatively low number of glycoproteins in its membrane, and the mechanism of Env recruitment and virus incorporation is incompletely understood. We employed dual-color super-resolution microscopy visualizing Gag assembly sites and HIV-1 Env proteins in virus-producing and in Env expressing cells. Distinctive HIV-1 Gag assembly sites were readily detected and were associated with Env clusters that always extended beyond the actual Gag assembly site and often showed enrichment at the periphery and surrounding the assembly site. Formation of these Env clusters depended on the presence of other HIV-1 proteins and on the long cytoplasmic tail (CT) of Env. CT deletion, a matrix mutation affecting Env incorporation or Env expression in the absence of other HIV-1 proteins led to much smaller Env clusters, which were not enriched at viral assembly sites. These results show that Env is recruited to HIV-1 assembly sites in a CT-dependent manner, while Env(ΔCT) appears to be randomly incorporated. The observed Env accumulation surrounding Gag assemblies, with a lower density on the actual bud, could facilitate viral spread . Keeping Env molecules on the nascent virus low may be important for escape from the humoral immune response, while cell-cell contacts mediated by surrounding Env molecules could promote HIV-1 transmission through the virological synapse

Conceptualizations, Images, and Evaluations of Culture in Study Abroad Students

AbstractThis article focuses on the cultural dimension of sojourners’ learning during study abroad periods. By examining the cases of two Canadian learners of German who studied abroad in Germany for 1 year, we aim to amend discussions in existing research on what kind of cultural learning may take place during study abroad and how cultural learning may be conceptualized and operationalized. Our results suggest that assuming that study abroad leads to a heightened intercultural sensitivity, to more cultural knowledge, and to an increased intercultural competence, is problematic with respect to the conceptual underpinnings of “cultural learning.” The notions of culture that underlie much of what participants consider “cultural learning and experience” often remain essentialist. We therefore propose to replace the interculturality paradigm by a transculturality paradigm as it allows us to capture the complexities of study abroad and cultural learning more accurately. RésuméCet article examine l’aspect culturel de l’expérience d’apprentissage lors de périodes d’échange à l’étranger. En nous appuyant sur l’exemple de deux apprenants canadiens de l’allemand qui ont passé une année en Allemagne, nous cherchons à contribuer à la discussion sur le type de connaissances culturelles acquises lors de l’échange et à préciser comment l’apprentissage culturel peut être conceptualisé et mis en usage. Les résultats de nos observations suggèrent qu’il est problématique de s’attendre à une augmentation de la sensibilité et de la compétence interculturelles et à l’apprentissage de la culture à cause de la notion même de « l’apprentissage culturel ». Les notions de culture qui sous-tendent ce que les participants considèrent comme « expérience et apprentissage culturels » restent souvent basiques. Alors, nous proposons de remplacer le paradigme interculturaliste par un paradigme transculturaliste, ce qui permettrait de mieux rendre compte de la complexité de l’expérience des échanges et de l’apprentissage culturel

Melem (2,5,8-Triamino-tri-s-triazine), an Important Intermediate during Condensation of Melamine Rings to Graphitic Carbon Nitride: Synthesis, Structure Determination by X-ray Powder Diffractometry, Solid-State NMR, and Theoretical Studies

Single-phase melem (2,5,8-triamino-tri-s-triazine) C6N7(NH2)3 was obtained as a crystalline powder by thermal treatment of different less condensed C−N−H compounds (e.g., melamine C3N3(NH2)3, dicyandiamide H4C2N4, ammonium dicyanamide NH4[N(CN)2], or cyanamide H2CN2, respectively) at temperatures up to 450°C in sealed glass ampules. The crystal structure was determined ab initio by X-ray powder diffractometry (Cu Kα1:  P21/c (No. 14), a = 739.92(1) pm, b = 865.28(3) pm, c = 1338.16(4) pm, β = 99.912(2)°, and Z = 4). In the solid, melem consists of nearly planar C6N7(NH2)3 molecules which are arranged into parallel layers with an interplanar distance of 327 pm. Detailed 13C and 15N MAS NMR investigations were performed. The presence of the triamino form instead of other possible tautomers was confirmed by a CPPI (cross-polarization combined with polarization inversion) experiment. Furthermore, the compound was characterized using mass spectrometry, vibrational (IR, Raman), and photoluminescence spectroscopy. The structural and vibrational properties of molecular melem were theoretically studied on both the B3LYP and the MP2 level. A structural optimization in the extended state was performed employing density functional methods utilizing LDA and GGA. A good agreement was found between the observed and calculated structural parameters and also for the vibrational frequencies of melem. According to temperature-dependent X-ray powder diffractometry investigations above 560°C, melem transforms into a graphite-like C−N material