2972 research outputs found
Sort by
Dynamically Self-Assembled Supramolecular Probes in Liposomes
Get PDFLiposomes are artificial vesicles, in which an aqueous inner compartment is separated from its environment by a phospholipid membrane. They have been extensively studied as cell membrane models and offer the possibility to confine molecules and chemical reactions to a small sub-micrometer-sized volume. This short review provides an overview of liposome-encapsulated, dynamically self-assembled, supramolecular structures, in which the assembly and disassembly of the supramolecular structures can be followed by optical spectroscopic methods. This includes self-quenched fluorescent dyes and dye/quencher pairs, helical stacks of guanosine nucleotides, dynamic covalent boronate esters, and supramolecular host–guest complexes. The resulting liposomes are typically used to study membrane transport processes, but the results summarized herein also serve as a potential blueprint for studying dynamic self-assembly in confined spaces by optical spectroscopic methods
Influence of Oxygen Plasma on the Growth and Stability of Epitaxial NiCo2O4 Ultrathin Films on Various Substrates
Get PDFIn this work, we investigated the influence of oxygen plasma on the growth of nickel cobaltite (NiCo2O4) thin films compared to growth in a molecular oxygen atmosphere. The films were grown on MgO(001), MgAl2O4(001) and SrTiO3(001) substrates by oxygen plasma (atmosphere of activated oxygen)-assisted and reactive molecular beam epitaxy (molecular oxygen atmosphere). Soft X-ray photoelectron spectroscopy showed that only the use of oxygen plasma led to a spectrum characteristic of (NiCo2O4). Low energy electron diffraction measurements were conducted to obtain information on the structure of the film surfaces. The results proved the formation of a spinel surface structure for films grown with oxygen plasma, while the formation of a rock salt structure was observed for growth with molecular oxygen. To determine the film thickness, X-ray reflectivity measurements were performed. If oxygen plasma were used to grow (NiCo2O4) films, this would result in lower film thicknesses compared to growth using molecular oxygen although the cation flux was kept constant during deposition. Additional X-ray diffraction experiments delivered structural information about the bulk structure of the film. All films had a rock salt bulk structure after exposure to ambient conditions. Angle-resolved hard X-ray photoelectron spectroscopy revealed a homogeneous depth distribution of cations of the grown film, but no typical (NiCo2O4) spectrum anymore. Thus, on the one hand, (NiCo2O4) films with a spinel structure prepared using activated oxygen were not stable under ambient conditions. The structure of these films was transformed into NiCo oxide with a rock salt structure. On the other hand, it was not possible to form (NiCo2O4) films using molecular oxygen. These films had a rock salt structure that was stable under ambient conditions
Aspects of Non-Equilibrium Behavior in Isolated Quantum Systems
Get PDFBased on the publications [P1–P6], the cumulative dissertation at hand addresses quite diverse
aspects of non-equilibrium behavior in isolated quantum systems. The works presented in
publications [P1, P2] concern the issue of finding generally valid upper bounds on equilibration
times, which ensure the eventual occurrence of equilibration in isolated quantum systems. Recently,
a particularly compelling bound for physically relevant observables has been proposed. Said
bound is examined analytically as well as numerically. It is found that the bound fails to give
meaningful results in a number of standard physical scenarios. Continuing, publication [P4]
examines a particular integral fluctuation theorem (IFT) for the total entropy production of a
small system coupled to a substantially larger but finite bath. While said IFT is known to hold
for canonical states, it is shown to be valid for microcanonical and even pure energy eigenstates
as well by invoking the physically natural conditions of “stiffness” and “smoothness” of transition
probabilities. The validity of the IFT and the existence of stiffness and smoothness are numerically
investigated for various lattice models. Furthermore, this dissertation puts emphasis on the issue
of the route to equilibrium, i.e., to explain the omnipresence of certain relaxation dynamics in
nature, while other, more exotic relaxation patterns are practically never observed, even though
they are a priori not disfavored by the microscopic laws of motion. Regarding this question, the
existence of stability in a larger class of dynamics consisting of exponentially damped oscillations
is corroborated in publication [P6]. In the same vein, existing theories on the ubiquity of certain
dynamics are numerically scrutinized in publication [P3]. Finally, in publication [P5], the recently
proposed “universal operator growth hypothesis”, which characterizes the complexity growth of
operators during unitary time evolution, is numerically probed for various spin-based systems in
the thermodynamic limit. The hypothesis is found to be valid within the limits of the numerical
approach
Willingness of the German population to donate toward bird conservation: An application of the protection motivation theory
Get PDFIn this study, the protection motivation theory (PMT) was used to investigate factors influencing self-reported willingness to donate and actual donations to conserve endangered bird species. The PMT was extended to include sociodemographic factors (gender, age, education, and income), as well as knowledge about and attitudes toward birds. Data were collected in Germany through an online questionnaire (N = 579, MAge = 49.15, SD = 16.93, women = 51.6 %). Regression analyses showed that the cognitive assessment processes of the PMT, (1) threat appraisal of endangered bird species, and (2) coping appraisal of threat toward endangered bird species were significant predictors of an individual’s willingness to donate. An individual’s attitudes toward birds strengthened willingness to donate, but not actual donations. Knowledge about birds had no influence on willingness to donate or actual donation behavior. Women were more likely to donate and higher perceived barriers were associated with lower rates of actual donations. A discrepancy between willingness to donate and actual donations is evident, which indicates an intention-behavior gap. The results suggest that conservation and education campaigns should be used to increase the population's awareness of existing threats toward endangered bird species, including the constructs of PMT, which could positively influence both willingness to donate and actual donations. Similarly, engagement initiatives could target individuals' self-efficacy to engage in bird conservation and possible coping measures should be made transparent and tangible by stakeholders looking to foster bird conservation
Digitalisierung, soziale Klasse und Corona – Berufliche Ungleichheiten in der Organisation des pandemiebedingten Homeoffice
No full textZusammenfassung: Als Beitrag zur Forschung über Ungleichheiten in der Digitalisierung von Arbeit
beschäftigt sich der Artikel mit dem pandemiebedingten Homeoffice. Mit Hilfe des Klassenansatzes
von Daniel Oesch wird untersucht, welchen Einfluss die berufliche Position auf die Organisation des
digital ermöglichten ortsflexiblen Arbeitens in der Corona-Krise hat. Dabei zeigt sich, dass die
Klassenlage nicht nur wesentlich den Zugang zum Homeoffice und das Ausmaß des Arbeitens von zu
Hause bestimmt. Die berufliche Position hat – trotz der relativ engen technologischen Basis des
pandemiebedingten Homeoffice – auch starken Einfluss auf die arbeitspolitische Qualität. Zum einen
sind die unteren Klassen beim Thema Homeoffice mehrfach unterprivilegiert: Beschäftigte in
Ausbildungsberufen und Anlerntätigkeiten haben in der Pandemie deutlich seltener die Möglichkeit,
von zu Hause zu arbeiten, und wenn sie doch die Gelegenheit haben, verbringen sie weniger Zeit im
Homeoffice und die arbeitspolitischen Bedingungen sind schlechter. Zum anderen finden sich auch
deutliche horizontale Differenzen. Die administrativen Berufe haben höhere Chancen, in der
Pandemie im Homeoffice zu landen, dort größere Zeitanteile zu verbringen und unter angemessenen
arbeitspolitischen Bedingungen zu arbeiten. Empirisch basiert der Beitrag auf qualitativen Interviews
(n=35) und einem Survey, an dem sich im Frühjahr 2021 und 2022 über 10.000 abhängig Beschäftigte
beteiligten.
Abstract: Contributing to the research on inequalities in the digitization of work, this article focuses
on the pandemic home office. Using Daniel Oesch's class approach, it examines the influence of the
occupational position on the organization of the digitally enabled home office during the Corona
crisis. It is shown that class position not only determines access to the home office and the extent to
which people work from home. Class location also – despite the relatively narrow technological basis
of pandemic home office - also has a strong influence on labor policy quality. On the one hand, the
lower classes are multiply underprivileged when it comes to home office: Workers in apprenticeship
and semiskilled jobs are significantly less likely to have the opportunity to work from home during
the pandemic, and when they do have the opportunity, they spend less time in the home office and
work-policy conditions are worse. On the other hand, we also find significant horizontal class
differences. Administrative occupations have higher odds of ending up in the home office during the
pandemic, spending larger shares of time there, and working under appropriate labor policy
conditions. Empirically, the paper is based on qualitative interviews (n=35) and a survey in which
more than 10,000 dependent employees participated in spring 2021 and 2022
Regionales Pflegekompetenzzentrum – Innovationsstrategie für die Langzeitversorgung vor Ort (ReKo). IT-Infrastrukturanalyse der Interventionsregion Landkreis Grafschaft Bentheim und Landkreis Emsland sowie der Kontrollregion Landkreise Cloppenburg, Oldenburg und Vechta. Basiserhebung t0 - 2020/2021.
No full textDer demografische Wandel führt dazu, dass die Gesellschaft immer älter wird und somit der Bedarf an gesundheitlicher und pflegerischer Versorgung steigt, während gleichzeitig ein Fachkräftemangel in der Pflege und im Gesundheitswesen allgemein besteht. Im Projekt „Regionales Pflegekompetenzzentrum – Innovationsstrategie für die Langzeitversorgung vor Ort“ (ReKo) wird in den Landkreisen Emsland und Grafschaft Bentheim untersucht, wie das Konzept regionaler Pflegekompetenzzentren dazu beitragen kann, pflegerische Versorgungssicherheit und -qualität in ländlichen Regionen zu unterstützen. Der Schwerpunkt liegt dabei auf einem differenzierten pflegeorientierten Case Management sowie einem unterstützenden digitalen Ökosystem. Gegenstand der Evaluation des ReKo-Projektes ist u.a. die Analyse der IT-Infrastruktur in der Interventions- und Kontrollregion. Im Rahmen der IT-Infrastrukturanalyse der Interventions- und Kontrollregion werden die Hardware- und Softwareausstattung der Akteure im Gesundheitswesen betrachtet, eine Impact-Analyse durchgeführt sowie Handlungsempfehlungen für die Versorgungspraxis abgeleitet
Regionale Case Management-Organisation mit digitalem Ökosystem - Projektbeschreibung Langversion
Get PDFDer Beitrag beschreibt das Innovationsfonds-Projekt des Gemeinsamen Bundesausschusses „Regionales Pflegekompetenzzentrum – Innovationsstrategie für die Langzeitversorgung vor Ort“ (ReKo). Im Rahmen des Projektes wird untersucht, wie ein differenziertes pflegeorientiertes Case Management-System sowie ein digitales Ökosystem, zur Unterstützung der Case Management-Prozesse und der Kommunikationen zwischen den beteiligten Akteuren im System, dazu beitragen können, die Versorgungssicherheit und -qualität in eher ländlich geprägten Regionen zu verbessern
Willkommenskultur
No full textDie Rede von der ‚Willkommenskultur‘ ist so geläufig wie problematisch, da ihr migrationspolitische Setzungen zugrunde liegen, welche Zuwanderung willkommen und welche nicht willkommen ist. Zuletzt diente ‚Willkommenskultur‘ in öffentlich-medialen Debatten, aber auch in der Migrationsforschung dazu, den vielfältigen und meist spontanen ehrenamtlichen Einsatz für Geflüchtete im Laufe des Jahres 2015 begrifflich zu fassen, ohne den Begriff weiter zu historisieren. Doch die Forderung nach einer ‚Willkommenskultur‘ tauchte schon Mitte der 2000er Jahre in Debatten rund um den Umgang mit in Berlin lebenden Zugewanderten auf und erlebte Anfang der 2010er Jahre im Rahmen bundespolitischer Auseinandersetzungen um den prognostizierten ‚Fachkräftemangel‘ ihren Durchbruch. Im Namen einer neuen ‚Willkommenskultur‘ wurde in erster Linie ein Paradigmenwechsel in der rechtlich-bürokratischen Praxis eingefordert: Weil sie als ‚Fachkräfte‘ gebraucht wurden, sollte der Aufenthalt für bestimmte ausländische Arbeitnehmer:innen attraktiver gestaltet und administrative Hürden daher abgebaut werden. Der vorliegende Beitrag spürt der kurzen Begriffsgeschichte der ‚Willkommenskultur‘ nach, beleuchtet die verschiedenen Bedeutungszusammenhänge und Sinnschichten und eröffnet kritische Perspektiven. Denn der Begriff verschleiert Kontinuitäten des gesellschaftlichen, politischen wie rechtlichen Ausschlusses von Migrant:innen in Deutschland und trägt dazu bei, eine folgenreiche Unterscheidung in erwünschte und unerwünschte Migration zu festigen
Insulator-Assisted Regular Arrays of Metal Centres via Metal-Organic Compounds
Get PDFMetal-organic network structures hold the strong promise for novel functionality in the fields of optoelectronics as well as information storage and processing. In this thesis, three different approaches for the formation of metal-organic compounds on insulating surfaces are followed using scanning probe microscopy (SPM) for characterisation of the resulting materials. First, steps towards on-surface synthesis of a metal-organic molecule are taken by investigating protoporphyrin IX on calcium fluoride (CaF2(111)) and silver (Ag(111)) surfaces. A particular focus is set on imaging the flexible molecular side groups with non-contact atomic force microscopy using CO functionalised tips. Second, the deposition and assembly of the metal-organic molecule ferrocenedicarboxylic acid is investigated on both bulk and thin film (111) surfaces of calcium fluoride. SPM experiments support a quadruped anchoring motif on both surfaces. Third, a regular array of metal centres is formed on Au(111) by assembly of trimesic acid and iron into a metal-organic network. A unique unit cell is identified from SPM data and the position of the metal centres within the unit cell is ascertained from determining the intermolecular distances in high-resolution non-contact atomic force microscopy images
Advances in Structural LEED Analyses of Silicon Surfaces
Get PDFLow-energy electron diffraction (LEED) is one possible experimental approach to determine atomic positions within the surface of crystalline surfaces. In this thesis, structural LEED analyses for the clean Si(001) surface as well as the Si(111)-(5 × 2)-Au reconstruction were performed. Additionally, the validity of the use of elastic strain energy as proposed by Keating was shown to improve the starting position for a structural analysis of covalent crystalline surfaces by LEED. Furthermore, an alternative approach to calculate the multiple scattering within the dynamical scattering theory was proposed. Thereby, LEED analyses of very large reconstructions and vicinal surfaces could become feasible