1,191 research outputs found
Improvement of the efficient referencing and sample positioning system for micro focused synchrotron X-ray techniques
An efficient referencing and sample positioning system is a basic tool for a micro focus beamline at a synchrotron. The seven years ago introduced command line based system was upgraded at SUL-X beamline at ANKA [1]. A new combination of current server client techniques offers direct control and facilitates unexperienced users the handling of this frequently used tool
A systemizing research framework for Web 2.0
Web 2.0 has recently been one of the most discussed topics in Information Systems science and practice. However, little consensus is found on what its components and characteristics actually are and what a comprehensive conceptualization might look like. This paper tries to shed light on these questions by systemizing the phenomenonâs characteristics in a hierarchical framework. In a first step, we apply content and cluster analysis on contributions of the field and inductively identify 103 raw categories which are then clustered into ten subcategories and two main categories. Namely these identified main categories of Web 2.0 are: âTechnological Characteristicsâ and âSocioeconomic Characteristicsâ. In a second step, we pretest and optimize the constructs for applicability and ambiguities and finally apply them to evaluate on the importance and weighting of the discovered subcategories. The resulting framework is found to comply with common quality measures for content analysis and classification schemes. It can be used to analyze and explore economic or social phenomena associated with Web 2.0 in a systematic manner
Building Taxonomies in IS and Management â A Systematic Approach Based on Content Analysis
Classification schemes such as taxonomies are important groundwork for research on many topics in Information Systems (IS) and Management. They make investigating topics manageable by allowing researchers to delimit their work to certain taxa or types and provide a basis for generalization. Opposed to theoretically grounded typologies, taxonomies are empirically derived from entities of a phenomenon under investigation and therefore have several advantages such as more detailed and exhaustive coverage. Nevertheless, research is still missing a clear set of procedures on how to empirically build taxonomies. We tackle this topic by suggesting an inductive approach based on the procedures of content and cluster analysis. Each of the proposed six steps is amended with comprehensive state of the art guidelines, suggestions, alternatives and formative measures of reliability and validity
Mongoose Manor: Herpestidae remains from the Early Pleistocene Cooperâs D locality in the Cradle of Humankind, Gauteng, South Africa
Mongooses (Herpestidae) are an important component of African ecosystems, and a common constituent of southern African fossil assemblages. Despite this, mongoose fossils from the Cradle of Humankind, Gauteng, South Africa, have received relatively little interest. This paper presents the diverse mongoose craniodental assemblage from the early Pleistocene fossil locality Cooperâs D. A total of 29 mongoose specimens from five genera were identified at Cooperâs, including numerous first appearances in the Cradle or in South Africa. The exceptional mongoose assemblage at Cooperâs likely reflects the effects of an unknown taphonomic process, although mongooses follow other carnivore groups in the Cradle in displaying an apparent preference for the southern part of the Cradle. This investigation shows the value of mongooses as palaeoecological indicators and supports previous interpretations of the environment at Cooperâs as grassland with a strong woody component near a permanent water source.Palaeontological Scientific Trust (PAST); DST-NRF Centre of Excellence, Palaeosciences (CoE-Pal); the South African National
Research Foundation; and the University of the Witwatersrand Postgraduate Merit
Award.JNC201
EXAFS studies of prostate cancer cell lines
Sulphur plays a vital role in every human organism. It is known, that sulphur-bearing compounds, such as for example cysteine and glutathione, play critical roles in development and progression of many diseases. Any alteration in sulphur's biochemistry could become a precursor of serious pathological conditions. One of such condition is prostate cancer, the most frequently diagnosed malignancy in the western world and the second leading cause of cancer related death in men. The purpose of presented studies was to examine what changes occur in the nearest chemical environment of sulphur in prostate cancer cell lines in comparison to healthy cells. The Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy was used, followed by theoretical calculations. The results of preliminary analysis is presented
Postshock Thermally Induced Transformations in Experimentally Shocked Magnetite
We studied the effect of 973 K heating in argon atmosphere on the magnetic and structural properties of a magnetiteâbearing ore, which was previously exposed to laboratory shock waves between 5 and 30 GPa. For this purpose magnetic properties were studied using temperatureâdependent magnetic susceptibility, magnetic hysteresis and lowâtemperature saturation isothermal remanent magnetization. Structural properties of magnetite were analyzed using Xâray diffraction, highâresolution scanning electron microscopy and synchrotronâassisted Xâray absorption spectroscopy. The shockâinduced changes include magnetic domain size reduction due to brittle and ductile deformation features and an increase in Verwey transition temperature due to lattice distortion. After heating, the crystal lattice is relaxed and apparent crystallite size is increased suggesting a recovery of lattice defects documented by a mosaic recrystallization texture. The structural changes correlate with modifications in magnetic domain state recorded by temperatureâdependent magnetic susceptibility, hysteresis properties and lowâtemperature saturation isothermal remanent magnetization. These alterations in both, magnetic and structural properties of magnetite can be used to assess impactârelated magnetic anomalies in impact structures with a high temperature overprint
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Circum-Mediterranean Neogene (Miocene and Pliocene) marine-continental chronologic correlations of European mammal units
This paper is an update of Steininger et al. 1989. It is mainly concerned with the chronologic correlation of the Miocene and Pliocene European Mammal Biozonations, the "European Neogene Mammal Faunal Zones" (MN zones, for discussion see Steininger et al. 1989) and the "European Mammal Faunal Units" (Agenic, Orleanic, etc., of Fahlbusch 1975; for discussion see Steininger et al. 1989), with the new Geomagnetic Polarity Time Scale (Cande and Kent 1992; in press) and the revised Geomagnetic Polarity Time Scale, Cenozoic Geochronology, Chronostratigraphy, and Planktonic Foraminifera Zonation (Berggren et al., in press). Within the last years rapid progress has been made in dating mammal-bearing Miocene and Pliocene sediments, either by radioisotopic dating (see also Swisher et al., this volume) and/or by geomagnetic dating (see also the following articles in this volume: Bernor et al.; Kappelman et al.: Sen; and Woodburne et al.). These recent results have been incorporated into this new data base. For a more recent compilation of the Pleistocene record see Agusti 1991 and Agusti et al. 1987
Fractal Noise in Quantum Ballistic and Diffusive Lattice Systems
We demonstrate fractal noise in the quantum evolution of wave packets moving
either ballistically or diffusively in periodic and quasiperiodic tight-binding
lattices, respectively. For the ballistic case with various initial
superpositions we obtain a space-time self-affine fractal which
verify the predictions by Berry for "a particle in a box", in addition to
quantum revivals. For the diffusive case self-similar fractal evolution is also
obtained. These universal fractal features of quantum theory might be useful in
the field of quantum information, for creating efficient quantum algorithms,
and can possibly be detectable in scattering from nanostructures.Comment: 9 pages, 8 postscript figure
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