The role of external broadcasting in a closed political system

This article investigates the role and impact of external broadcasting (radio and television) on a closed political system, through the example of the two post-war German states: the West German Federal Republic of Germany (FRG) and the East German German Democratic Republic (GDR). The aim is to debunk myths about the influence of external broadcasting on the events that led to German reunification in 1990. The study follows a historical approach and discusses what role external media played during the years of a divided Germany. The findings are based on several historical sources, research reports from the 1950s and 1960s and over 100 biographical interviews with former residents of the German Democratic Republic (GDR). The article analyses the impact of external broadcasting on citizens and the political elite in times of crisis as well as during everyday life

Assessing and monitoring student progress in e-learning environments

E-learning has emerged as a form of pedagogy and as a delivery system with broad implications for meeting personnel needs nationally in special education. At present, it is important to make investments in research and development to ensure that this new pedagogy becomes fully developed and is appropriately applied. Assessment and monitoring of student progress in e-learning environments is an important element of this new form of pedagogy that requires research attention to maximize the effectiveness of e-learning when applied to teacher education. The authors draw upon their personal online teaching experience in addressing strategies for assessing student performance and using electronic portfolios in e-learning environments, both presented as integral aspects of e-learning instructional process. Perspectives from the literature and lessons learned from the authors’ own experience are shared.peerreviewe

Synthesis and biological evaluation of carbamates derived from aminocombretastatin A-4 as vascular disrupting agents

A series of t wenty-six carbamates derived from aminocombretastatin A- 4 (AmCA-4 ) were syn thesized and evaluated for their capacity to affect cell proliferation, tubulin polymerization, mitotic cell arrest, microtubule network organization, apoptos is and endothelial tubular structures in vitro. The anti- pro liferative activity of the synthetic carbamates was measured on several human tumor cell lines (i.e. HT-29, MCF-7, HeLa, A-549, MDA-MB-231, H L-60) as well as on the endothelial cell line HMEC-1 and the non-tumor cell line H EK-293. The compounds showed anti-proliferative activity in the nanomolar range thereby exceeding by far the activity of combretastatin A-4 (CA-4 ) and, in some cases, the activity of AmCA-4. The most active compounds proved to be the carbamates bearing chloro, bromo or methoxy groups in the meta position of the phenyl ring. Moreover, all carbamates inhibited in vitro tubulin polymerization, in a similar manne r to that of CA-4 and Am CA-4 by interacting with the colchicine binding site in tubulin. The synthetic carbamates proved as active as AmCA-4 in causing mitotic arrest, as asses sed in A549 human lung cancer cells, and disruption of the microtubule ce llular network. Some selected carbamates induced apoptosis at concentrations as low as 10 nM, being more active than AmCA-4. Final ly, these selected carbamates displayed a vascular disrupting activity on endothelial cells in a dose-dependent manner. In conclusion, our data indicate that carbamates derived from aminocombretastatin A-4 represent interesting lead compounds for the design of vascular dis- rupting agent

β\beta-BaB2_2O4_4 deep UV monolithic walk-off compensating tandem

The generation of watt-level cw narrow-linewidth sources at specific deep UV wavelengths corresponding to atomic cooling transitions usually employs external cavity-enhanced second-harmonic generation (SHG) of moderate-power visible lasers in birefringent materials. In this work, we investigate a novel approach to cw deep-UV generation by employing the low-loss BBO in a monolithic walkoff-compensating structure [Zondy {\it{et al}}, J. Opt. Soc. Am. B {\bf{20}} (2003) 1675] to simultaneously enhance the effective nonlinear coefficient while minimizing the UV beam ellipticity under tight focusing. As a preliminary step to cavity-enhanced operation, and in order to apprehend the design difficulties stemming from the extremely low acceptance angle of BBO, we investigate and analyze the single-pass performance of a $L_c=8$mm monolithic walk-off compensating structure made of 2 optically-contacted BBO plates cut for type-I critically phase-matched SHG of a cw $\lambda=570.4$nm dye laser. As compared with a bulk crystal of identical length, a sharp UV efficiency enhancement factor of 1.65 has been evidenced with the tandem structure, but at $\sim-1$nm from the targeted fundamental wavelength, highlighting the sensitivity of this technique when applied to a highly birefringent material such as BBO. Solutions to angle cut residual errors are identified so as to match accurately more complex periodic-tandem structure performance to any target UV wavelength, opening the prospect for high-power, good beam quality deep UV cw laser sources for atom cooling and trapping.Comment: 21 pages, 8 figures, to appear in Opt. Commu

Stipa pungens Nees & Meyen

ArequipapublishedVersio

Dynamic Carboniferous tropical forests: new views of plant function and potential for physiological forcing of climate

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138385/1/nph14700_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138385/2/nph14700.pd

Arteries are formed by vein-derived endothelial tip cells

Tissue vascularization entails the formation of a blood vessel plexus, which remodels into arteries and veins. Here we show, by using time-lapse imaging of zebrafish fin regeneration and genetic lineage tracing of endothelial cells in the mouse retina, that vein-derived endothelial tip cells contribute to emerging arteries. Our movies uncover that arterial-fated tip cells change migration direction and migrate backwards within the expanding vascular plexus. This behaviour critically depends on chemokine receptor cxcr4a function. We show that the relevant Cxcr4a ligand Cxcl12a selectively accumulates in newly forming bone tissue even when ubiquitously overexpressed, pointing towards a tissue-intrinsic mode of chemokine gradient formation. Furthermore, we find that cxcr4a mutant cells can contribute to developing arteries when in association with wild-type cells, suggesting collective migration of endothelial cells. Together, our findings reveal specific cell migratory behaviours in the developing blood vessel plexus and uncover a conserved mode of artery formation.Supramolecular & Biomaterials Chemistr

Foliar Morphology And Anatomy Of The Gigantopterid Plant Delnortea Abbottiae, From The Lower Permian Of West Texas

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142005/1/ajb214202.pd