Search results for " sphere"
showing 10 items of 404 documents
Political candidates in infotainment programmes and their emotional effects on Twitter: an analysis of the 2015 Spanish general elections pre-campaig…
2017
[EN] The infotainment format offers candidates an informal setting to show a more personal side of themselves to the electorate, opening themselves up to potential voters. An example of media hybridisation, social networks users can immediately comment on infotainment television programmes, a process known as second screening. These second screeners tend to be especially active in politics. This paper analyses the immediate emotional reaction of these users as they watch infotainment programmes that air during the campaign or pre-campaign seasons and feature political candidates as guests. We have confirmed that second screeners react more emotionally towards the candidate when his or her p…
La herida original de las políticas de inmigración : A propósito del lugar de los derechos humanos en las políticas de inmigración
2002
El artículo plantea algunas condiciones que permitan superar las dos posiciones en las que parece alternativamente preso el debate actual sobre la inmigración: la visión instrumental, torpemente pragmática, y la «humanitaria», anclada en la conmiseración o la piedad. Para alcanzar la dimensión política es preciso superar un análisis de los flujos migratorios erróneo, el que está en la base de ambas posiciones. Y si se supera esa visión, se superarán los actuales instrumentos jurídicos de política de inmigración, que no son acordes con el reconocimiento pleno y la garantía de los derechos humanos fundamentales, pero tampoco con el necesario reconocimiento de la condición de sujeto del espaci…
Uniform continuity of quasiconformal mappings and conformal deformations
2008
We prove that quasiconformal maps onto domains satisfying a suitable growth condition on the quasihyperbolic metric are uniformly continuous even when both domains are equipped with internal metric. The improvement over previous results is that the internal metric can be used also in the image domain. We also extend this result for conformal deformations of the euclidean metric on the unit ball of R n \mathbb {R}^n .
Privacy in Social Network Sites
2011
Are we running out of privacy? Nowadays, for example, we are concerned about whether the maintenance of a private sphere in online environments has become a luxury commodity (Papacharissi 2009). Questions of this kind are justified as online communication plays an increasingly important role in people’s everyday life (cf., e.g., Lundby 2009). While it seems exaggerated to stigmatize today’s youth as “communication junkies” (Patalong 2010), online conversations are increasingly becoming a functional equivalent to face to face communication (Beer 2008). However, some significant differences between online and “offline” communication remain. Face to face communication may remain largely intima…
Diastereospecific control in the synthesis of enantiomerically pure bis-equatorial rhodium(II) catalysts by chiral phosphanes
2000
The reaction of Rh2(O2CR)4 [R = CH3, CF3] with the chiral phosphane (1S,2S,5R)-(2-hydroxy-5-isopropenyl-2-methylcyclohexyl)(diphenyl)phosphane, (+)PPh2(CH−R*−OH) or its enantiomer (1R,2R,5S)-(2-hydroxy-5-isopropenyl-2-methylcyclohexyl)(diphenyl)phosphane, (−)-PPh2(CH−R*−OH), results in the specific formation of the products (P)-Rh2(μ-O2CR)2(η1-O2CR)2{η2-(+)PPh2(CH−R*−OH)}2 [P(+)1, R = CH3; P(+)2 R = CF3] and (M)-Rh2(μ-O2CR)2(η1-O2CR)2{η2-(−)-PPh2(CH−R*−OH)}2 [M(−)1, R = CH3; M(−)2, R = CF3] in a high yield. Their synthesis, characterisation and catalytic behaviour in metal−carbenoid reactions are reported. X-ray analysis of P(+)2 and M(−)2 shows, in each case, a Rh24+ unit supported by two …
3d/4f Sandwich Complex Based on Metallacrowns.
2021
A novel lanthanide double-decker complex with nickel metallacrowns (MCs) as coordinating ligands has been synthesized. In the 3d/4f metallacrown complex TbIII[12-MCNiIIN(shi)-4]2, the central lanthanide ion is sandwiched between two [12-MC-4] units, forming an almost ideal square-antiprismatic coordination sphere. The resulting zenithal angles at the central lanthanide ion are smaller than those for previously reported sandwich compounds. Magnetic measurements reveal an energy barrier of 346 K under zero field and up to 585 K under 3200 Oe, the highest reported for metallacrowns with D4d symmetry.
“Hard” Sphere Behavior of “Soft”, Globular-like, Hyperbranched Polyglycerols – Extensive Molecular Hydrodynamic and Light Scattering Studies
2020
Whether or not hyperbranched polymers behave like quasi “hard spheres” in solution is the subject of numerous fundamental discussions, also motivated by research on the perfectly branched dendrimer...
Structural Transformations and Magnetic Effects Induced by Solvent Exchange in the Spin Crossover Complex [Fe(bpp) 2 ][Cr(bpy)(ox) 2 ] 2
2005
Structural, thermal, magnetic and solvent-exchange properties of the spin crossover compound [Fe(bpp)2][Cr(bpy)(ox)2]2 containing paramagnetic anions are given. This complex salt 1 crystallises as a dihydrate with two inequivalent (high-spin and low-spin) FeII sites. The dehydrated compound is a spin-crossover material with T1/2 ↑ = 369 K and T1/2 ↓ = 353 K. Rehydration takes place without loss of crystallinity, yielding a polymorph (2) with 100 % high-spin Fe II sites. The different high-spin fractions in 1 and 2 have been correlated to structural changes in the FeII second coordination sphere. The magnetic response to the presence of different sorbed molecules has also been explored. © Wi…
Custom coordination environments for lanthanoids: tripodal ligands achieve near-perfect octahedral coordination for two dysprosium-based molecular na…
2017
Controlling the coordination sphere of lanthanoid complexes is a challenging critical step toward controlling their relaxation properties. Here we present the synthesis of hexacoordinated dysprosium single-molecule magnets, where tripodal ligands achieve a near-perfect octahedral coordination. We perform a complete experimental and theoretical investigation of their magnetic properties, including a full single-crystal magnetic anisotropy analysis. The combination of electrostatic and crystal-field computational tools (SIMPRE and CONDON codes) allows us to explain the static behavior of these systems in detail. NRF-2015R1A2A1A10055658 Grant NRF-2012-0008901 NRF2010-0020209 ERC-CoG-647301 DEC…
Coordinatively Unsaturated Lanthanide(III) Helicates: Luminescence Sensors for Adenosine Monophosphate in Aqueous Media
2016
Coordinatively unsaturated double-stranded helicates [(H2 L)2 Eu2 (NO3 )2 (H2 O)4 ](NO3 )4 , [(H2 L)2 Tb2 (H2 O)6 ](NO3 )6 , and [(H2 L)2 Tb2 (H2 O)6 ]Cl6 (H2 L=butanedioicacid-1,4-bis[2-(2-pyridinylmethylene)hydrazide]) are easily obtained by self-assembly from the ligand and the corresponding lanthanide(III) salts. The complexes are characterized by X-ray crystallography showing the helical arrangement of the ligands. Co-ligands at the metal ions can be easily substituted by appropriate anions. A specific luminescence response of AMP in presence of ADP, ATP, and other anions is observed. Specificity is assigned to the perfect size match of AMP to bridge the two metal centers and to replac…