6,887 research outputs found
An Economic Approach to Article 82
This report argues in favour of an economics-based approach to Article 82, in a way similar to the reform of Article 81 and merger control. In particular, we support an effects-based rather than a form-based approach to competition policy. Such an approach focuses on the presence of anti-competitive effects that harm consumers, and is based on the examination of each specific case, based on sound economics and grounded on facts
An Economic Approach to Article 82 - Report by the European Advisory Group on Competition Policy
This report argues in favour of an economics-based approach to Article 82, in a way similar to the reform of Article 81 and merger control. In particular, we support an effects-based rather than a form-based approach to competition policy. Such an approach focuses on the presence of anti-competitive effects that harm consumers, and is based on the examination of each specific case, based on sound economics and grounded on facts.Competition Policy; Abuse of Market Power; Article 82
Correlation Between Student Collaboration Network Centrality and Academic Performance
We compute nodal centrality measures on the collaboration networks of
students enrolled in three upper-division physics courses, usually taken
sequentially, at the Colorado School of Mines. These are complex networks in
which links between students indicate assistance with homework. The courses
included in the study are intermediate Classical Mechanics, introductory
Quantum Mechanics, and intermediate Electromagnetism. By correlating these
nodal centrality measures with students' scores on homework and exams, we find
four centrality measures that correlate significantly with students' homework
scores in all three courses: in-strength, out-strength, closeness centrality,
and harmonic centrality. These correlations suggest that students who not only
collaborate often, but also collaborate significantly with many different
people tend to achieve higher grades. Centrality measures between simultaneous
collaboration networks (analytical vs. numerical homework collaboration)
composed of the same students also correlate with each other, suggesting that
students' collaboration strategies remain relatively stable when presented with
homework assignments targeting different skills. Additionally, we correlate
centrality measures between collaboration networks from different courses and
find that the four centrality measures with the strongest relationship to
students' homework scores are also the most stable measures across networks
involving different courses. Correlations of centrality measures with exam
scores were generally smaller than the correlations with homework scores,
though this finding varied across courses.Comment: 10 pages, 4 figures, submitted to Phys. Rev. PE
An Economic Approach to Article 82
This report argues in favour of an economics-based approach to Article 82, in a way similar to the reform of Article 81 and merger control. In particular, we support an effects-based rather than a form-based approach to competition policy. Such an approach focuses on the presence of anti-competitive effects that harm consumers, and is based on the examination of each specific case, based on sound economics and grounded on facts.competition policy; abuse of market power
Does ultrasonic dispersion and homogenization by ball milling change the chemical structure of organic matter in geochemical samples?—a CPMAS 13C NMR study with lignin
6 pages, 2 figures, 2 tables, 23 references.Ultrasonic dispersion of geochemical samples suspended in water and subsequent homogenization by ball milling is widely used for fractionation of organic matter. The effect of these treatments on organic matter is investigated with lignin as a model compound. Structural alterations detectable by solid-state 13C nuclear magnetic resonance (NMR) spectroscopy were examined. Comparison of the solid-state 13C NMR spectra of untreated lignin and lignin mixed with quartz or soil did not reveal evidence for structural changes in the organic matter composition after ultrasonic dispersion and subsequent ball-milling. The chemical structure of organic matter in geochemical samples is not affected by these treatments as far as such structural alterations can be detected by solid-state 13C NMR spectroscopy.This work was financially supported
by the Deutsche Forschungsgemeinschaft (Ko 1035/6-land
2) and the Deutscher Akademischer Austauschdienst (Ref.
315, D/94/16993).Peer reviewe
Airborne contamination of forest soils by carbonaceous particles from industrial coal processing
In the German Ruhr-area industrial coal processing emitted large amounts of carbonaceous particles for a century until 1970. Our objectives were to detect the presence of airborne carbonaceous particles and assess their impact on the chemical structure of soil organic matter in two forest soils (Podzols) with potential sources of carbonaceous particles approximately 10 to 30 km away. Contamination was not visible macroscopicaily. Organic matter was characterized in bulk soils and in particle-size separates by elemental analysis, magnetic susceptibility measurement, reflected light microscopy, and 13C solid-state nuclear magnetic resonance (NMR) spectroscopy. Organic and mineral horizons contained carbonaceous particles including char, coke, and bituminous coal from coal combustion, coking, coal processing, and steel production. In the organic horizons of both soils we observed a material high in magnetic susceptibility (max. 109 × 10−8 m3 kg−1), whereas in the mineral horizons only the Podzol with an intense intermixing moder-type humus had high magnetic susceptibly. This Aeh horizon was extremely rich in organic carbon (139.4 g organic C kg−1), concentrated in the 20 to 2000 µm size separates. In the second Podzol, like in many natural soils, C concentrations were largest in the <20 µm separates. Bloch decay 13C magic angle spinning (MAS) NMR spectroscopy revealed a highly aromatic structure of the carbonaceous particles. Airborne carbonaceous particles formed a macroscopically indistinguishable mixture with natural soil organic matter and could be present in many soils neighboring industrialized areas.Peer reviewe
High-Resolution Spectroscopic Study of Extremely Metal-Poor Star Candidates from the SkyMapper Survey
The SkyMapper Southern Sky Survey is carrying out a search for the most
metal-poor stars in the Galaxy. It identifies candidates by way of its unique
filter set that allows for estimation of stellar atmospheric parameters. The
set includes a narrow filter centered on the Ca II K 3933A line, enabling a
robust estimate of stellar metallicity. Promising candidates are then confirmed
with spectroscopy. We present the analysis of Magellan-MIKE high-resolution
spectroscopy of 122 metal-poor stars found by SkyMapper in the first two years
of commissioning observations. 41 stars have [Fe/H] <= -3.0. Nine have [Fe/H]
<= -3.5, with three at [Fe/H] ~ -4. A 1D LTE abundance analysis of the elements
Li, C, Na, Mg, Al, Si, Ca, Sc, Ti, Cr, Mn, Co, Ni, Zn, Sr, Ba and Eu shows
these stars have [X/Fe] ratios typical of other halo stars. One star with low
[X/Fe]
[X/Fe values appears to be "Fe-enhanced," while another star has an extremely
large [Sr/Ba] ratio: >2. Only one other star is known to have a comparable
value. Seven stars are "CEMP-no" stars ([C/Fe] > 0.7, [Ba/Fe] < 0). 21 stars
exhibit mild r-process element enhancements (0.3 <=[Eu/Fe] < 1.0), while four
stars have [Eu/Fe] >= 1.0. These results demonstrate the ability to identify
extremely metal-poor stars from SkyMapper photometry, pointing to increased
sample sizes and a better characterization of the metal-poor tail of the halo
metallicity distribution function in the future.Comment: Minor corrections to text, missing data added to Tables 3 and 4;
updated to match published version. Complete tables included in sourc
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