Greek Economists for Reform.com

This blog publishes articles by leading academic economists on issues relevant to economic policy and reforms in Greece. The crisis in Greece is also a time of opportunity: ambitious reforms can be undertaken that will not only stave off bankruptcy, but also modernize Greece’s economy and raise the productivity and incomes of Greek citizens on a sustainable basis. The articles in this blog aim to offer constructive proposals and impartial analysis of potential, proposed or implemented reforms that are based on the principles of modern economics and on lessons from recent cutting-edge research.

Nutzungspotentiale interner Weblogs bei RobinBook.ch

Die interne Kommunikation ist ein zentrales Element erfolgreicher Unternehmensführung. Sie generiert Wissen, welches für die Innovations- und Produktivitätskraft eines Unternehmens entscheidend ist. Je grösser und internationaler dieses jedoch ist, desto schwieriger wird die Vernetzung der Mitarbeiter und der Austausch von Wissen. Heutzutage bietet das Web 2.0 durch interaktive und kollaborative Elemente Wege für einen offenen und transparenten Informationsfluss. Weblogs, Soziale Netzwerke oder Wikis sind beliebte Werkzeuge der Verbreitung von Informationen und Förderung eines kommunikativen Austauschs, da sie durch einfache Bedienung nicht nur IT- Spezialisten vorbehalten sind. In diesem Beitrag wird anhand eines Fallbeispiels gezeigt, wie durch einen intern genutzten Weblog (kurz Blog) eine Alternative zum herkömmlichen Intranet geboten werden kann, um Unternehmen zu vernetzen und dadurch einen Wissensaustausch zu ermöglichen.

The Changing Environment of Audiovisual Media. New Technologies, New Patterns of Consumer/Business Behaviour and Their Implications for Audiovisual Media Regulation

Digital TV offers of 200 channels and 500 video-on-demand films, podcasting, mobile television, a new web blog being created every two seconds - these are some of the factual elements depicting contemporary audiovisual media in the digital environment. The present article looks into some of these technological advances and sketches their implications for the markets of media content, in particular as newly emerging patterns of consumer and business behaviour are concerned. Ultimately, it puts forward the question of whether the existing audiovisual media regulatory models, which are still predominantly analogue-based, have been rendered obsolete by the transformed (and continually transforming) digital environment.

Ayamama, retour sur un bassin-versant après l’inondation de septembre 2009. Compte-rendu de l’excursion urbaine du 25 novembre 2009

Report of an urban excursion organized in Istanbul by Jean-François Pérouse (Observatoire Urbain d'Istanbul - Institut Français d'Etudes Anatoliennes)

Diversity of morphological patterns in supramolecular polymers formed from the amphiphilic oligomers of pyrenes

Herein we demonstrate that a substitution type of the pyrene in short amphiphilic oligomers determines a morphology of the assemblies formed. Thus, 1.6- and 2.7-linkages lead to a formation of micrometer-sized 2D supromolecular polymers with a constant thickness 2 nm (pictures A and B). These assemblies possess a high degree of an internal order: the interior consists of hydrophobic pyrenes and alkyl chains, whereas the exterior exists as a net of hydrophilic negatively charged phosphates. Contrary, a 1.8-linkage exclusiveley leads to a formation of long nanometer thick helical supramolecular polymers (picturee C). These structures tend to form even more complex assemblies (bundles, superhelixes). Moreover, for all samples the polymerization process occurs via a nucleation-elongation mechanism. To study Py3 self-assembly, we carried out whole set of spectroscopic (UV/vis, fluorescence, DLS) and microscopic experiments (AFM).

Hierarchical self-assembly of nucleotide-appended oligopyrenotides into defined supramolecular objects

Supramolecular DNA assembly blends DNA building blocks with synthetic organic molecules giving structural and functional advantages. Incorporating extended aromatic molecules as connectors of DNA strands allows folding of these strands through π-π stacking (DNA 'foldamers'). In previous work it was shown that short oligopyrenotides behave as staircase-like foldamers, which cooperatively self-assemble into 2D supramolecular polymers in aqueous medium. Herein, we demonstrate that 10-mer DNA-sequence conjugated with seven pyrene unites forms dimensionally-defined supramolecular polymers under thermodynamic conditions in water. We present the self-assembly behavior, morphologycal studies (AFM and TEM), and the spectroscopic properties (UV/vis, CD) of the investigated pyrene - conjugated DNA-sequence.

Formation of supramolecular polymers by chrysene oligomers

Supramolecular assembly of π-conjugated systems is of large interested due to the possibility to use them in electronic devices.[1] Chrysene is a polyaromatic hydrocarbon which has been studied e.g for organic light-emitting diodes (OLEDs).[2] In continuation of our previous work involving the supramolecular polymerisation of pyrene oligomers [3] an oligomer consisting of three chrysenes linked by phophodiesters was synthesised (Chry3). UV-Vis measurements show that aggregates of Chry3 are formed in aqueous medium. This is illustrated by general hypochromicity, a change in vibronic band intensities and, in particular, the appearance of a red-shifted absorption band in the S0 → S2 transition. The data suggest the formation of J-aggregates. The formation of supramolecular polymers is further studied by temperature-dependent absorption- and fluorescence measurements, and by atomic force microscopy (AFM).

A modular LHC built on the DNA three-way junction

Over the past years, in numerous studies the DNA double helix serves as a scaffold for the controlled arrangement of functional molecules, including a wide range of different chromophores. Other nucleic acid structures like the DNA three-way junction have been exploited for this purpose as well. Recently, the successful development of DNA-based light-harvesting antenna systems have been reported. Herein, we describe the use of the DNA three-way junction (3WJ) as a versatile scaffold for the modular construction of an artificial light harvesting complex (LHC). The LHC is based on a modular construction in which a phenanthrene antenna is located in one of the three stems and the acceptor is brought into proximity of the antenna through the annealing of the third strand. Phenanthrene excitation (320 nm) is followed by energy transfer to pyrene (resulting in exciplex emission), perylenediimide (quencher) or a cyanine dye (cyanine fluorescence).

From supramolecular sheets to fibers and back: establishing the critical parameters that govern the morphology of pyrene-based self-assembled materials

The precise arraying of functional entities in morphologically well-defined shapes remains one of the key challenges in the processing of organic molecules1. Among various π-conjugated species, pyrene exhibits a set of unique properties, which make it an attractive compound for the utilization in materials science2. In this contribution we report on properties of self-assembled structures prepared from amphiphilic pyrene trimers (Py3) consisting of phosphodiester-linked pyrenes. Depending on the geometry of a pyrene core substitution (1.6-, 1.8-, or 2.7- type, see Scheme), the thermally-controlled self-assembly allows the preparation of supramolecular architectures of different morphologies in a bottom-up approach: two-dimensional (2D) nanosheets3 are formed in case of 1.6- and 2.7-substitution4 whereas one-dimensional (1D) fibers are built from 1.8- substituted isomers. The morphologies of the assemblies are established by AFM and TEM, and the results are further correlated with spectroscopic and scattering data. Two-dimensional assemblies consist of an inner layer of hydrophobic pyrenes, sandwiched between a net of phosphates. Due to the repulsion of the negative charges, the 2D assemblies exist mostly as free-standing sheets. An internal alignment of pyrenes leads to strong exciton coupling with an unprecedented observation (simultaneous development of J- and H-bands from two different electronic transitions). Despite the similarity in spectroscopic properties, the structural parameters of the 2D aggregates drastically depend on the preparation procedure. Under certain conditions extra-large sheets (thickness of 2 nm, aspect ratio area/thickness ~107) in aqueous solution are formed4B. Finally, one-dimensional assemblies are formed as micrometer-long and nanometer-thick fibers. Both, planar and linear structures are intriguing objects for the creation of conductive nanowires that may find interest for applications in supramolecular electronics.