830 research outputs found
Combining EPR spectroscopy and X ray crystallography to elucidate the structure and dynamics of conformationally constrained spin labels in T4 lysozyme single crystals
Electron paramagnetic resonance (EPR) spectroscopy in combination with site-directed spin labeling is used to investigate the structure and dynamics of conformationally constrained spin labels in T4 lysozyme single crystals. Within a single crystal, the oriented ensemble of spin bearing moieties results in a strong angle dependence of the EPR spectra. A quantitative description of the EPR spectra requires the determination of the unit cell orientation with respect to the sample tube and the orientation of the spin bearing moieties within the crystal lattice. Angle dependent EPR spectra were analyzed by line shape simulations using the stochastic Liouville equation approach developed by Freed and co-workers and an effective Hamiltonian approach. The gain in spectral information obtained from the EPR spectra of single crystalline samples taken at different frequencies, namely the X-band and Q-band, allows us to discriminate between motional models describing the spectra of isotropic solutions similarly well. In addition, it is shown that the angle dependent single crystal spectra allow us to identify two spin label rotamers with very similar side chain dynamics. These results demonstrate the utility of single crystal EPR spectroscopy in combination with spectral line shape simulation techniques to extract valuable dynamic information not readily available from the analysis of isotropic systems. In addition, it will be shown that the loss of electron density in high resolution diffraction experiments at room temperature does not allow us to conclude that there is significant structural disorder in the system
Challenging assumptions of the enlargement literature : the impact of the EU on human and minority rights in Macedonia
This article argues that from the very start of the transition process in Macedonia, a fusion of concerns about security and democratisation locked local nationalist elites and international organisations intoa political dynamic that prioritised security over democratisation. This dynamic resulted in little progress in the implementation of human and minority rights until 2009, despite heavy EU involvement in Macedonia after the internal warfare of 2001. The effects of this informally institutionalised relationship have been overlooked by scholarship on EU enlargement towards Eastern Europe, which has made generalisations based on assumptions relevant to the democratisation of countries in Eastern Europe, but not the Western Balkans
Turkish Accession and Defining the Boundaries of Nationalism and Supranationalism: Discourses in the European Commission
The European Union in general and the European Commission in particular are
characterised by supranational governance. The enlargement policy gives the Commission
the opportunity to export and promote supranational norms and define the boundaries of
Europe as a supranational polity through the conditionality of membership and intensive
contact with the candidate countries. This article analyses the discourses of the
Commission on Turkey and gives us insights into how well Turkey fits the supranational
model in the eyes of Commission officials. It demonstrates how the boundaries of
supranationalism are set and even challenged by the prospects of Turkeyâs accession
Environmental governance in a contested state:the influence of European Union and other external actors on energy sector regulation in Kosovo
This article examines environmental governance in Kosovo, with a particular focus on the energy sector. The article considers the degree to which the emerging model of environmental governance is characterised by hierarchical and non-hierarchical modes of coordination. We examine the roles of a number of domestic institutions and actors â ministries, agencies, and regulatory bodiesâ and the influence of external actors, including the EU, the US, and Serbia. The EU is building Kosovoâs own hierarchical governance capacity by strengthening domestic institutions, whilst the US focuses primarily on market liberalization, whilst simultaneously supporting EU efforts. Moreover, environmental policy change is not wholly or predominantly driven by domestic actors, which can partly be attributed to Kosovoâs limited domestic sovereignty. We conclude that the emerging model of environmental governance in Kosovo is characterized by a weak hierarchy, partly as a result of external actor involvement, which disincentivises the government from responding to domestic non-state actor pressure
Towards an improved understanding of biogeochemical processes across surface-groundwater interactions in intermittent rivers and ephemeral streams
Surface-groundwater interactions in intermittent rivers and ephemeral streams (IRES), waterways which do not flow year-round, are spatially and temporally dynamic because of alternations between flowing, non-flowing and dry hydrological states. Interactions between surface and groundwater often create mixing zones with distinct redox gradients, potentially driving high rates of carbon and nutrient cycling. Yet a complete understanding of how underlying biogeochemical processes across surface-groundwater flowpaths in IRES differ among various hydrological states remains elusive. Here, we present a conceptual framework relating spatial and temporal hydrological variability in surface water-groundwater interactions to biogeochemical processing hotspots in IRES. We combine a review of theIRES biogeochemistry literature with concepts of IRES hydrogeomorphology to: (i) outline common distinctions among hydrological states in IRES; (ii) use these distinctions, together with considerations of carbon, nitrogen, and phosphorus cycles within IRES, to predict the relative potential for biogeochemical processing across different reach-scale processing zones (flowing water, fragmented pools, hyporheic zones, groundwater, and emerged sediments); and (iii) explore the potential spatial and temporal variability of carbon and nutrient biogeochemical processing across entire IRES networks. Our approach estimates the greatest reach-scale potential for biogeochemical processing when IRES reaches are fragmented into isolated surface water pools, and highlights the potential of relatively understudied processing zones, such as emerged sediments. Furthermore, biogeochemical processing in fluvial networks dominated by IRES is likely more temporally than spatially variable. We conclude that biogeochemical research in IRES would benefit from focusing on interactions between different nutrient cycles, surface-groundwater interactions in non-flowing states, and consideration of fluvial network architecture. Our conceptual framework outlines opportunities to advance studies and expand understanding of biogeochemistry in IRES
The Pinochet case : cosmopolitanism and intermestic human rights
This article explores the Pinochet case, widely heralded as a landmark, as a case of âintermesticâ human rights that raises difficult normative and empirical questions concerning cosmopolitan justice. The article is a contribution to the sociology of human rights from the perspective of methodological cosmopolitanism, developing conceptual tools and methods to study how cosmopolitanising state institutions and cultural norms are inter-related. The argument is made that in order to understand issues of cosmopolitan justice, sociologists must give more consideration to political culture
Radio emission of highly inclined cosmic ray air showers measured with LOPES
LOPES-10 (the first phase of LOPES, consisting of 10 antennas) detected a
significant number of cosmic ray air showers with a zenith angle larger than
50, and many of these have very high radio field strengths. The most
inclined event that has been detected with LOPES-10 has a zenith angle of
almost 80. This is proof that the new technique is also applicable
for cosmic ray air showers with high inclinations, which in the case that they
are initiated close to the ground, can be a signature of neutrino events.Our
results indicate that arrays of simple radio antennas can be used for the
detection of highly inclined air showers, which might be triggered by
neutrinos. In addition, we found that the radio pulse height (normalized with
the muon number) for highly inclined events increases with the geomagnetic
angle, which confirms the geomagnetic origin of radio emission in cosmic ray
air showers.Comment: A&A accepte
Results from the KASCADE, KASCADE-Grande, and LOPES experiments
The origin of high-energy cosmic rays in the energy range from 10^14 to 10^18
eV is explored with the KASCADE and KASCADE-Grande experiments. Radio signals
from air showers are measured with the LOPES experiment. An overview on results
is given.Comment: Talk at The ninth International Conference on Topics in Astroparticle
and Underground Physics, TAUP 2005, Zaragoza, September 10-14, 200
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