Raumorientiertes Risikomanagement in Technik und Umwelt: ökonomische versus ökologische Sicht

Risiken in Technik und Umwelt sind keine besonderen Risiken, sondern Teil des Umstandes, dass Handeln stets unter Unsicherheit über die Zukunft erfolgt. Sie sind komplex und realisieren sich in der Regel so fern vom „verursachenden“ Akteur, dass der Grundsatz des „rational choice“-Denkens, „die Risiken sollen den Chancen folgen“, nicht realisierbar ist. Ein Grundproblem der Raumordnung im Umgang mit Risiken ist, nicht klar zwischen Gefahr und Risiko trennen zu können, wobei ihre Risiken komplexe, kontingente Situationen darstellen, die spezifischer Handhabung bedürfen. Häufig betreffen im Bereich der Raumordnung Risiken nicht monetär bewertbare „Schäden“. Auf Grund der Komplexität und des zeitlichen und räumlichen Auseinanderfallens von Chancen und Risiken muss in Zukunft weniger auf die Risikominderung als auf die Verwundbarkeit (Vulnerabilität) geachtet werden. Die im Falle des Marktversagens vorgesehene Konsenslösung über die Hinnahme von Risiken führt zu einer Externalisierung in die Zukunft bzw. zu Lasten anderer Regionen sowie in Sonderheit der Natur.Risks in technology and the environment are not special risks but form part of the circumstances that result in action always being linked to uncertainty about the future. They are complex and are generally caused by the “party responsible” if the principle of the “rational choice” way of thinking i.e. “opportunities are likely to be followed by risks” cannot be implemented. A fundamental problem of spatial planning in dealing with risks is the difficulty in clearly separating danger from risk, whereby the risks represent complex, contingent situations that require specific management. In the area of spatial planning, risks often relate to “damage” that cannot be evaluated in terms of money. In view of their complexity and the time-related and spatial divergence between opportunities and risks, in future, more attention must be paid to vulnerability rather than to risk minimisation. The consensus solution planned in the event of market failure, which relates to the acceptance of risks, leads to an externalisation towards the future or at the cost of other regions as well as nature in particular

A Fluorescence-Based Method to Measure ADP/ATP Exchange of Recombinant Adenine Nucleotide Translocase in Liposomes

Several mitochondrial proteins, such as adenine nucleotide translocase (ANT), aspartate/glutamate carrier, dicarboxylate carrier, and uncoupling proteins 2 and 3, are suggested to have dual transport functions. While the transport of charge (protons and anions) is characterized by an alteration in membrane conductance, investigating substrate transport is challenging. Currently, mainly radioactively labeled substrates are used, which are very expensive and require stringent precautions during their preparation and use. We present and evaluate a fluorescence-based method using Magnesium Green (MgGrTM), a Mg2+-sensitive dye suitable for measurement in liposomes. Given the different binding affinities of Mg2+ for ATP and ADP, changes in their concentrations can be detected. We obtained an ADP/ATP exchange rate of 3.49 ± 0.41 mmol/min/g of recombinant ANT1 reconstituted into unilamellar liposomes, which is comparable to values measured in mitochondria and proteoliposomes using a radioactivity assay. ADP/ATP exchange calculated from MgGrTM fluorescence solely depends on the ANT1 content in liposomes and is inhibited by the ANT-specific inhibitors, bongkrekic acid and carboxyatractyloside. The application of MgGrTM to investigate ADP/ATP exchange rates contributes to our understanding of ANT function in mitochondria and paves the way for the design of other substrate transport assays

Vergleichbarkeit manueller und automatischer Haubenmesstechnik zur Erfassung des Ökosystem-CO2-Austauschs

Eine insbesondere für kleinräumige Parzellenversuche gut geeignete Methode zur Quantifizierung des Ökosystem-CO2-Austauschs basiert auf periodischen Messkampagnen mit einem manuellen non-flow-through non-steady-state Haubensystem (Livingston und Hutchinson 1995; Drösler 2005). Da die Datenlücken zwischen den einzelnen Messkampagnen durch Modellierung auf Basis kontinuierlicher Witterungsdaten geschlossen werden, hängt die Güte der Ergebnisse stark von der Frequenz der Messkampagnen und der Passfähigkeit der ermittelten Modellparameter für die Zeiträume zwischen den Kampagnen ab. Der Einsatz eines automatischen Mess-systems mit transparenten Hauben liefert fortlaufend hochaufgelöste Messdaten für den Netto-Ökosystemaustausch (NEE; tagsüber) und Ökosystematmung (Reco; nachts) und begrenzt die Modellierung auf kurze Zeiträume, in denen die Technik z.B. wegen Bewirtschaftungs-maßnahmen deinstalliert werden muss. Eine Kombination manuell und automatisch erhobener CO2-Flussraten wäre zur Erhöhung der Zuverlässigkeit der modellierten CO2-Austauschraten sinnvoll, erfordert jedoch Untersuchungen darüber, ob bzw. unter welchen Voraussetzungen das möglich ist. Ergebnisse von Vergleichsmessungen der beiden Messsysteme zu drei verschiedenen Terminen (2011/2012) zeigen, dass beide Messsysteme tagsüber (NEE) prinzipiell vergleichbare Ergebnisse liefern und somit eine NEE-Modellierung auf Basis kombinierter manuell und automatisch ermittelter CO2-Flussraten zulässig ist. Nachts (Reco) weist jedoch das manuelle Messsystem leicht höhere Flussraten als die automatischen Hauben auf, so dass die Messsysteme diesbezüglich nur eingeschränkt kombinierbar sind. Mögliche Ursachen der Differenzen sind in weiteren Versuchen zu analysieren

Molecular dynamics simulations of mitochondrial uncoupling protein 2

Molecular dynamics (MD) simulations of uncoupling proteins (UCP), a class of transmembrane proteins relevant for proton transport across inner mitochondrial membranes, represent a complicated task due to the lack of available structural data. In this work, we use a combination of homology modelling and subsequent microsecond molecular dynamics simulations of UCP2 in the DOPC phospholipid bilayer, starting from the structure of the mitochondrial ATP/ADP carrier (ANT) as a template. We show that this protocol leads to a structure that is impermeable to water, in contrast to MD simulations of UCP2 structures based on the experimental NMR structure. We also show that ATP binding in the UCP2 cavity is tight in the homology modelled structure of UCP2 in agreement with experimental observations. Finally, we corroborate our results with conductance measurements in model membranes, which further suggest that the UCP2 structure modeled from ANT protein possesses additional key functional elements, such as a fatty acid-binding site at the R60 region of the protein, directly related to the proton transport mechanism across inner mitochondrial membranes

Continuum Halos in Nearby Galaxies -- an EVLA Survey (CHANG-ES) -- II: First Results on NGC 4631

We present the first results from the CHANG-ES survey, a new survey of 35 edge-on galaxies to search for both in-disk as well as extra-planar radio continuum emission. The motivation and science case for the survey are presented in a companion paper (Paper I). In this paper (Paper II), we outline the observations and data reduction steps required for wide-band calibration and mapping of EVLA data, including polarization, based on C-array test observations of NGC 4631. With modest on-source observing times (30 minutes at 1.5 GHz and 75 minutes at 6 GHz for the test data) we have achieved best rms noise levels of 22 and 3.5 $\mu$Jy beam$^{-1}$ at 1.5 GHz and 6 GHz, respectively. New disk-halo features have been detected, among them two at 1.5 GHz that appear as loops in projection. We present the first 1.5 GHz spectral index map of NGC 4631 to be formed from a single wide-band observation in a single array configuration. This map represents tangent slopes to the intensities within the band centered at 1.5 GHz, rather than fits across widely separated frequencies as has been done in the past and is also the highest spatial resolution spectral index map yet presented for this galaxy. The average spectral index in the disk is $\bar\alpha_{1.5 GHz}\,=\,-0.84\,\pm\,0.05$ indicating that the emission is largely non-thermal, but a small global thermal contribution is sufficient to explain a positive curvature term in the spectral index over the band. Two specific star forming regions have spectral indices that are consistent with thermal emission. Polarization results (uncorrected for internal Faraday rotation) are consistent with previous observations and also reveal some new features. On broad scales, we find strong support for the notion that magnetic fields constrain the X-ray emitting hot gas.Comment: Accepted to the Astronomical Journal, Version 2 changes: Added acknowledgement to NRA

Bow-tie optical antenna probes for single-emitter scanning near-field optical microscopy

A method for the fabrication of bow-tie optical antennas at the apex of pyramidal Si3N4 atomic force microscopy tips is described. We demonstrate that these novel optical probes are capable of sub-wavelength imaging of single quantum dots at room temperature. The enhanced and confined optical near-field at the antenna feed gap leads to locally enhanced photoluminescence (PL) of single quantum dots. Photoluminescence quenching due to the proximity of metal is found to be insignificant. The method holds promise for single quantum emitter imaging and spectroscopy at spatial resolution limited by the engineered antenna gap width exclusively

ANT1 Activation and Inhibition Patterns Support the Fatty Acid Cycling Mechanism for Proton Transport

Adenine nucleotide translocase (ANT) is a well-known mitochondrial exchanger of ATP against ADP. In contrast, few studies have shown that ANT also mediates proton transport across the inner mitochondrial membrane. The results of these studies are controversial and lead to different hypotheses about molecular transport mechanisms. We hypothesized that the H+-transport mediated by ANT and uncoupling proteins (UCP) has a similar regulation pattern and can be explained by the fatty acid cycling concept. The reconstitution of purified recombinant ANT1 in the planar lipid bilayers allowed us to measure the membrane current after the direct application of transmembrane potential ΔΨ, which would correspond to the mitochondrial states III and IV. Experimental results reveal that ANT1 does not contribute to a basal proton leak. Instead, it mediates H+ transport only in the presence of long-chain fatty acids (FA), as already known for UCPs. It depends on FA chain length and saturation, implying that FA’s transport is confined to the lipid-protein interface. Purine nucleotides with the preference for ATP and ADP inhibited H+ transport. Specific inhibitors of ATP/ADP transport, carboxyatractyloside or bongkrekic acid, also decreased proton transport. The H+ turnover number was calculated based on ANT1 concentration determined by fluorescence correlation spectroscopy and is equal to 14.6 ± 2.5 s−1. Molecular dynamic simulations revealed a large positively charged area at the protein/lipid interface that might facilitate FA anion’s transport across the membrane. ANT’s dual function—ADP/ATP and H+ transport in the presence of FA—may be important for the regulation of mitochondrial membrane potential and thus for potential-dependent processes in mitochondria. Moreover, the expansion of proton-transport modulating drug targets to ANT1 may improve the therapy of obesity, cancer, steatosis, cardiovascular and neurodegenerative diseases

Continuum Halos in Nearby Galaxies -- an EVLA Survey (CHANG-ES) -- I: Introduction to the Survey

We introduce a new survey to map the radio continuum halos of a sample of 35 edge-on spiral galaxies at 1.5 GHz and 6 GHz in all polarization products. The survey is exploiting the new wide bandwidth capabilities of the Karl G. Jansky Very Large Array (i.e. the Expanded Very Large Array, or EVLA) in a variety of array configurations (B, C, and D) in order to compile the most comprehensive data set yet obtained for the study of radio halo properties. This is the first survey of radio halos to include all polarization products. In this first paper, we outline the scientific motivation of the survey, the specific science goals, and the expected improvements in noise levels and spatial coverage from the survey. Our goals include investigating the physical conditions and origin of halos, characterizing cosmic ray transport and wind speed, measuring Faraday rotation and mapping the magnetic field, probing the in-disk and extraplanar far-infrared - radio continuum relation, and reconciling non-thermal radio emission with high-energy gamma-ray models. The sample size allows us to search for correlations between radio halos and other properties, including environment, star formation rate, and the presence of AGNs. In a companion paper (Paper II) we outline the data reduction steps and present the first results of the survey for the galaxy, NGC 4631.Comment: 17 pages, 1 figure, accepted to the Astronomical Journal, Version 2 changes: added acknowledgement to NRA