6,054 research outputs found
Ökologischer Kreislauf Moorbad Harbach: Life Cycle Assessment (LCA) for Agricultural Plant Production and Transportation
In 1992 the community of Moorbad Harbach (Austria), located near the border of the Czech Republic and dominated by extensive agricultural practice on small scale farms, decided to initiate activities for regional devolopment. About 40 farms (27 %) converted to organic farming, a local marketing service as well as regional food processing businesses (slaughterhouse, dairy), operating as linkages between regional agriculture and the local spa hotel were founded. The basic idea for the work presented here was to evaluate the – especially ecological – consequences of such a regional conversion. One part of this attempt of evaluation was carried out as a LCA for the agricultural production in Moorbad Harbach. The emphasis of the study was to compare plant production before and after the regional conversion to organic farming. In another step changes in transportation distances and quantities with special regard to transport of raw milk and milk products were quantified
The ethical challenge of Touraine's 'living together'
In Can We Live Together? Alain Touraine combines a consummate analysis of crucial social tensions in contemporary societies with a strong normative appeal for a new emancipatory 'Subject' capable of overcoming the twin threats of atomisation or authoritarianism. He calls for a move from 'politics to ethics' and then from ethics back to politics to enable the new Subject to make a reality out of the goals of democracy and solidarity. However, he has little to say about the nature of such an ethics. This article argues that this lacuna could usefully be filled by adopting a form of radical humanism found in the work of Erich Fromm. It defies convention in the social sciences by operating from an explicit view of the 'is' and the 'ought' of common human nature, specifying reason, love and productive work as the qualities to be realised if we are to move closer to human solidarity. Although there remain significant philosophical and political differences between the two positions, particularly on the role to be played by 'the nation', their juxtaposition opens new lines of inquiry in the field of cosmopolitan ethics
Erfolgsfaktoren für regionale Vermarktungsprojekte im Ökologischen Landbau
Unter den vielen, in den letzten Jahren entstandenen regionalen Vermarktungskooperationen zwischen LandwirtInnenen bzw. zwischen LandwirtInnen sowie Verarbeitungs- und Vermarktungseinrichtungen sind einige sehr erfolgreiche Initiativen zu finden. In diesen Fällen ist von Interesse, welche Faktoren und Bedingungen es ermöglichen, dass ein derartiges Projekt „gelingt“ und über längere Zeitdauer bestehen bleibt
Jet-torus connection in radio galaxies: Relativistic hydrodynamics and synthetic emission
High-resolution Very-Long-Baseline Interferometry observations of active
galactic nuclei have revealed asymmetric structures in the jets of radio
galaxies. These asymmetric structures may be due to internal asymmetries in the
jet, could be induced by the different conditions in the surrounding ambient
medium including the obscuring torus, or a combination of the two. In this
paper we investigate the influence of the ambient medium (including the
obscuring torus) on the observed properties of jets from radio galaxies. We
performed special-relativistic hydrodynamic (RHD) simulations of over-pressured
and pressure-matched jets using the special-relativistic hydrodynamics code
\texttt{Ratpenat}, which is based on a second-order accurate finite-volume
method and an approximate Riemann solver. Using a newly developed emission code
to compute the electromagnetic emission, we have investigated the influence of
different ambient medium and torus configurations on the jet structure and
subsequently computed the non-thermal emission produced by the jet and the
thermal absorption due to the torus. To better compare the emission simulations
with observations we produced synthetic radio maps, taking into account the
properties of the observatory. The detailed analysis of our simulations shows
that the observed asymmetries can be produced by the interaction of the jet
with the ambient medium and by the absorption properties of the obscuring
torus.Comment: 14 pages, 17 figures, submitted to A&
F-GAMMA: On the phenomenological classification of continuum radio spectra variability patterns of Fermi blazars
The F-GAMMA program is a coordinated effort to investigate the physics of
Active Galactic Nuclei (AGNs) via multi-frequency monitoring of Fermi blazars.
In the current study we show and discuss the evolution of broad-band radio
spectra, which are measured at ten frequencies between 2.64 and 142 GHz using
the Effelsberg 100-m and the IRAM 30-m telescopes. It is shown that any of the
78 sources studied can be classified in terms of their variability
characteristics in merely 5 types of variability. It is argued that these can
be attributed to only two classes of variability mechanisms. The first four
types are dominated by spectral evolution and can be described by a simple
two-component system composed of: (a) a steep quiescent spectral component from
a large scale jet and (b) a time evolving flare component following the
"Shock-in-Jet" evolutionary path. The fifth type is characterised by an
achromatic change of the broad band spectrum, which could be attributed to a
different mechanism, likely involving differential Doppler boosting caused by
geometrical effects. Here we present the classification, the assumed physical
scenario and the results of calculations that have been performed for the
spectral evolution of flares.Comment: Proceedings of the conference: "The Central Kiloparsec in Galactic
Nucleic: Astronomy at High Angular Resolution 2011", August 29 - September 2,
2011, Bad Honnef, German
Erfolgsfaktoren für regionale Vermarktungsprojekte im Ökologischen Landbau
Unter den vielen, in den letzten Jahren entstandenen regionalen Vermarktungskooperationen zwischen LandwirtInnen bzw. zwischen LandwirtInnen sowie Verarbeitungs- und Vermarktungseinrichtungen sind einige sehr erfolgreiche Initiativen zu finden. Welche Faktoren und Bedingungen es ermöglichen, dass ein derartiges Projekt „gelingt“ und über längere Zeitdauer bestehen bleibt, wurde im Rahmen eines Workshops in Kooperation der Institute für Ökologischen Landbau und Agrarökonomik mit StudentInnen sowie vier ExpertInnen aus der Praxis erarbeitet
Catching the Radio Flare in CTA 102 III. Core-Shift and Spectral Analysis
The temporal and spatial spectral evolution of the jets of AGN can be studied
with multi-frequency, multi-epoch VLBI observations. The combination of both,
morphological and spectral parameters can be used to derive source intrinsic
physical properties such as the magnetic field and the non-thermal particle
density. In the first two papers of this series, we analyzed the single-dish
light curves and the VLBI kinematics of the blazar CTA 102 and suggested a
shock-shock interaction between a traveling and a standing shock wave as a
possible scenario to explain the observed evolution of the component associated
to the 2006 flare. In this paper we investigate the core-shift and spectral
evolution to test our hypothesis of a shock-shock interaction. We used 8
multi-frequency VLBA observations to analyze the temporal and spatial evolution
of the spectral parameters during the flare. We observed CTA 102 between May
2005 and April 2007 using the VLBA at six different frequencies spanning from 2
- 86 GHz. After the calibrated VLBA images were corrected for opacity, we
performed a detailed spectral analysis. From the derived values we estimated
the magnetic field and the density of the relativistic particles. The detailed
analysis of the opacity shift reveals that the position of the jet core is
proportional to nu^-1 with some temporal variations. The value suggests
possible equipartition between magnetic field energy and particle kinetic
energy densities at the most compact regions. From the variation of the
physical parameters we deduced that the 2006 flare in CTA 102 is connected to
the ejection of a new traveling feature (t=2005.9) and the interaction between
this shock wave and a stationary structure around 0.1 mas from the core. The
source kinematics together with the spectral and structural variations can be
described by helical motions in an over-pressured jet.Comment: 35 pages, 46 figure
The impact of the Kasatochi eruption on the Moon's illumination during the August 2008 lunar eclipse
The Moon's changeable aspect during a lunar eclipse is largely attributable
to variations in the refracted unscattered sunlight absorbed by the terrestrial
atmosphere that occur as the satellite crosses the Earth's shadow. The
contribution to the Moon's aspect from sunlight scattered at the Earth's
terminator is generally deemed minor. However, our analysis of a published
spectrum of the 16 August 2008 lunar eclipse shows that diffuse sunlight is a
major component of the measured spectrum at wavelengths shorter than 600 nm.
The conclusion is supported by two distinct features, namely the spectrum's
tail at short wavelengths and the unequal absorption by an oxygen collisional
complex at two nearby bands. Our findings are consistent with the presence of
the volcanic cloud reported at high northern latitudes following the 7-8 August
2008 eruption in Alaska of the Kasatochi volcano. The cloud both attenuates the
unscattered sunlight and enhances moderately the scattered component, thus
modifying the contrast between the two contributions.Comment: Accepted for publication in Geophysical Research Letter
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