56,964 research outputs found

    Correlative Microscopy of Morphology and Luminescence of Cu porphyrin aggregates

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    Transfer of energy and information through molecule aggregates requires as one important building block anisotropic, cable-like structures. Knowledge on the spatial correlation of luminescence and morphology represents a prerequisite in the understanding of internal processes and will be important for architecting suitable landscapes. In this context we study the morphology, fluorescence and phosphorescence of molecule aggregate structures on surfaces in a spatially correlative way. We consider as two morphologies, lengthy strands and isotropic islands. It turns out that phosphorescence is quite strong compared to fluorescence and the spatial variation of the observed intensities is largely in line with the amount of dye. However in proportion, the strands exhibit more fluorescence than the isotropic islands suggesting weaker non-radiative channels. The ratio fluorescence to phosphorescence appears to be correlated with the degree of aggregation or internal order. The heights at which luminescence saturates is explained in the context of attenuation and emission multireflection, inside the dye. This is supported by correlative photoemission electron microscopy which is more sensitive to the surface region. The lengthy structures exhibit a pronounced polarization dependence of the luminescence with a relative dichroism up to about 60%, revealing substantial perpendicular orientation preference of the molecules with respect to the substrate and parallel with respect to the strands

    No entailing laws, but enablement in the evolution of the biosphere

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    Biological evolution is a complex blend of ever changing structural stability, variability and emergence of new phenotypes, niches, ecosystems. We wish to argue that the evolution of life marks the end of a physics world view of law entailed dynamics. Our considerations depend upon discussing the variability of the very "contexts of life": the interactions between organisms, biological niches and ecosystems. These are ever changing, intrinsically indeterminate and even unprestatable: we do not know ahead of time the "niches" which constitute the boundary conditions on selection. More generally, by the mathematical unprestatability of the "phase space" (space of possibilities), no laws of motion can be formulated for evolution. We call this radical emergence, from life to life. The purpose of this paper is the integration of variation and diversity in a sound conceptual frame and situate unpredictability at a novel theoretical level, that of the very phase space. Our argument will be carried on in close comparisons with physics and the mathematical constructions of phase spaces in that discipline. The role of (theoretical) symmetries as invariant preserving transformations will allow us to understand the nature of physical phase spaces and to stress the differences required for a sound biological theoretizing. In this frame, we discuss the novel notion of "enablement". This will restrict causal analyses to differential cases (a difference that causes a difference). Mutations or other causal differences will allow us to stress that "non conservation principles" are at the core of evolution, in contrast to physical dynamics, largely based on conservation principles as symmetries. Critical transitions, the main locus of symmetry changes in physics, will be discussed, and lead to "extended criticality" as a conceptual frame for a better understanding of the living state of matter

    Nano-structures at martensite macrotwin interfaces in Ni65Al35Ni_{65}Al_{35}

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    The atomic configurations at macrotwin interfaces between microtwinned martensite plates in Ni65Al35Ni_{65}Al_{35} material are investigated using transmission electron microscopy. The observed structures are interpreted in view of possible formation mechanisms for these interfaces. A distinction is made between cases in which the microtwins, originating from mutually perpendicular \{110\} austenite planes, enclose a final angle larger or smaller than 90∘90^{\circ}. Two different configurations, a crossing and a step type are described. Depending on the actual case, tapering, bending and tip splitting of the smaller microtwin variants are observed. The most reproducible deformations occur in a region of approximately 5-10nm width around the interface while a variety of structural defects are observed further away from the interface. These structures and deformations are interpreted in terms of the coalescence of two separately nucleated microtwinned martensite plates and the need to accommodate remaining stresses

    Bologna changes in MA degree programmes. Convergence of the public administration programmes in South-Eastern Europe

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    The provisions of Bologna Declaration are ongoing implemented in several South- Eastern European states, members or non members of the European Union. For most states, important restructuring processes for the legal framework and organisation system of higher education were imperative. At the same time, the content of the programmes for all the three cycles was revised in order to follow closely the finalities stipulated in the European documents, substantiating the European Higher Education Area. In this context, the current paper aims to carry out the comparative analysis for the actual level attained by the mentioned states in implementing Bologna Process, with special attention towards higher education in the area of public administration. Research teams, led by the author of this paper have analysed the degree of curricular compatibility of the Bachelor programmes from various European states. This time, the research will focus on describing the process of convergence related to the delivery modalities and the content of the Master programmes in the area of public administration, corresponding to the second cycle of Bologna system. The indicators of convergence will be defined related to the standards of evaluation,used by EAPAA for accreditation of the public administration programmes.Bologna process,M A public administration programmes,convergence
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