Search results for "figuration"
showing 10 items of 615 documents
Embeddings of graph braid and surface groups in right-angled Artin groups and braid groups
2003
We prove by explicit construction that graph braid groups and most surface groups can be embedded in a natural way in right-angled Artin groups, and we point out some consequences of these embedding results. We also show that every right-angled Artin group can be embedded in a pure surface braid group. On the other hand, by generalising to right-angled Artin groups a result of Lyndon for free groups, we show that the Euler characteristic -1 surface group (given by the relation x^2y^2=z^2) never embeds in a right-angled Artin group.
Heterogeneous Photocatalysis for Selective Formation of High-Value-Added Molecules: Some Chemical and Engineering Aspects
2018
This review deals with the parameters that influence heterogeneous photocatalysis (PC) for selective synthesis of high-value chemicals by itself or in combination with other technologies. In particular, the parameters related to the photocatalysts, such as crystallinity degree, type of polymorph, surface acid-base properties, exposure of particular crystalline facets, coupling of different semiconductors, position of the valence and conduction band edge, addition of doping agents, and those related to the reaction system, such as setup configuration and reactor geometry, type of solvent, type and amount of photocatalyst, affecting the selectivity toward specific products are described and d…
Chiral cyclohexane based fluorescent chemosensors for enantiomeric discrimination of aspartate
2008
Some new chiral cyclohexyl based fluorescent anion receptors have been synthesized and their absolute configuration has been determined by using circular dichroism (CD). Complexation experiments have been carried out with several dicarboxylates, and stoichiometries and complexation constants for the corresponding complexes have been determined. The chiral discrimination ability of these ligands for chiral dicarboxylates has been studied and the best results have been obtained with TMA aspartate.
Prolin-benzylester als chirale Hilfsgruppen in asymmetrischen 1,3-dipolaren Cycloadditionen mit Nitriloxiden
1990
Proline Benzyl Esters as Chiral Auxiliaries in Asymmetric 1,3-Dipolar Cycloadditions N-Acryloylproline benzyl ester (1b) reacts with nitrile oxides at temperatures from −78 to 0°C to give isoxazolines 4/5 with diastereomeric ratios of ca. 3:1 and with the (5S) isomer as the predominating. The corresponding N-methacryloylproline benzyl ester (1c) gives inferior results. The diastereoselectivity is not influenced by the temperature and the substituents of the nitrile oxides. To prove the absolute configuration of the predominating stereoisomer, a reaction sequence is developed which makes use of an enantioselective hydrolysis with pig liver esterase as the key step to generate an optically ac…
Bis[S-hexyl 3-(thiophen-2-ylmethylidene)dithiocarbazato-κ2N3,S]palladium(II)
2016
In the title complex, [Pd(C12H17N2S3)2], the PdIIatom exhibits a square-planar coordination geometry with theN,S-chelating ligands arranged in atransconfiguration. Intramolecular C—H...S hydrogen bonds are observed. In the crystal, molecules are linked by weak C—H...N hydrogen-bond interactions, forming chains parallel to thebaxis.
Dynamic properties of successful plural leadership configuration: An exploratory process-study
2023
Our article introduces an exploratory process study of successful plural leadership configuration in searching for alternative solutions to wicked problems. The study was executed within four educational organisations that solved challenging wicked problems arising from today’s changing contexts. We argue that plural leadership configuration is a dynamic process when people in diverse organisational positions, roles, and levels design profitable endeavours through their ideas and activities, bring about desirable outcomes within diverse conditions and outline the future. We searched for potential systemic patterns, characteristics, and structure within this dynamic process. To find these p…
“When You Live Here, That’s What You Get”: Other-, Ex-, and Non-Religious Outsiders in the Norwegian Bible Belt
2019
This article presents data from our investigations in Kristiansand, the largest city in Southern Norway, an area sometimes called Norway&rsquo
Op art et roman virtuel : correspondances entre Escher et Perec
2012
Op art et roman virtuel : correspondances entre Escher et Perec Les structures mathématiques, la notion de réalité comme « humaine illusion », le défi à l’infini et la structure énigmatique qui donne aux œuvres eschériennes la même structure que celle d’un roman policier permettent d’établir des convergences significatives entre le graveur hollandais et Georges Perec. Dans certaines œuvres de Perec, en effet, il est possible de remarquer des références explicites au graveur bien qu’elles constituent la traduction visuelle de l’angoisse du « retour du semblable », du « retour involontaire au même point ». Mais Perec ne se limite pas seulement à citer Escher, puisque certaines de ses œuvres c…
Sustainable virtual teams: promoting well-being through affect management training and openness to experience configurations
2021
A disruptive digitalization recently occurred that led to the fast adoption of virtual teams. However, membership diversity and team virtuality threaten members’ well-being, especially if faultlines appear (i.e., subgroups). Considering the job demands–resources model and the role of group affect in shaping members’ perceptions of well-being, we test the effectiveness of a short-term affect management training for increasing members’ eudaimonic well-being. Moreover, based on the trait activation theory and the contingent configuration approach, we draw on the personality composition literature to test how different openness to experience configurations of team level and diversity together m…
Struktur-Wirkungs-Beziehungen bei Histaminanaloga, 18. Mitt. Absolute Konfiguration und histaminartige Wirkung der Enantiomere von 5-Amino-4,5,6,7-te…
1979
Es werden die Racemattrennung von 5-Amino-4,5,6,7-tetrahydro-benzimidazol (3), die Bestimmung der absoluten Konfiguration sowie die histaminartige Wirksamkeit der Enantiomere am Ileum (H1) und Atrium (H2) des Meerschweinchens beschrieben. Structure-Activity Relationship of Histamine Analogues, XVIII: Absolute Configuration and Histamine-like Activity of the Enantiomers of 5-Amino-4,5,6,7-tetrahydrobenzimidazole The resolution of 5-amino-4,5,6,7-tetrahydrobenzimidazole (3), the determination of the absolute configuration and the histamine-like activity of the enantiomers on the guinea-pig ileum (H1) and atrium (H2) are reported.