539 research outputs found
Online Dating in Tension Between Romantic Love and Economic Rationalization
This paper will at first show how romantic love and economic rationality have emerged in modernity as two distinct spheres, which are characterized by their own normative principles, expectations und practical orientations - two spheres that have systematically been opposed in sociological tradition. In a second part, it will be analyzed how these two distinct sets of normative principles and practical orientations are bath introduced into the field of online dating. This leads to the third part which investigates on an empirical basis how people deal with the ambivalences and tensions between these different orientations in the practice of online dating. Finally, a short conclusion questions if the boundaries between love and the market are being blurred or, in a fragile way, re-established on the Internet today
Advanced dextran based nanogels for fighting Staphylococcus aureus infections by sustained zinc release
Inhibition of activation of transcription factor AP-1 by CD28 signalling in human T-cells
The band structure of BeTe - a combined experimental and theoretical study
Using angle-resolved synchrotron-radiation photoemission spectroscopy we have
determined the dispersion of the valence bands of BeTe(100) along ,
i.e. the [100] direction. The measurements are analyzed with the aid of a
first-principles calculation of the BeTe bulk band structure as well as of the
photoemission peaks as given by the momentum conserving bulk transitions.
Taking the calculated unoccupied bands as final states of the photoemission
process, we obtain an excellent agreement between experimental and calculated
spectra and a clear interpretation of almost all measured bands. In contrast,
the free electron approximation for the final states fails to describe the BeTe
bulk band structure along properly.Comment: 21 pages plus 4 figure
Interchange Slip-Running Reconnection and Sweeping SEP Beams
We present a new model to explain how particles (solar energetic particles;
SEPs), accelerated at a reconnection site that is not magnetically connected to
the Earth, could eventually propagate along the well-connected open flux tube.
Our model is based on the results of a low-beta resistive magnetohydrodynamics
simulation of a three-dimensional line-tied and initially current-free bipole,
that is embedded in a non-uniform open potential field. The topology of this
configuration is that of an asymmetric coronal null-point, with a closed fan
surface and an open outer spine. When driven by slow photospheric shearing
motions, field lines, initially fully anchored below the fan dome, reconnect at
the null point, and jump to the open magnetic domain. This is the standard
interchange mode as sketched and calculated in 2D. The key result in 3D is
that, reconnected open field lines located in the vicinity of the outer spine,
keep reconnecting continuously, across an open quasi-separatrix layer, as
previously identified for non-open-null-point reconnection. The apparent
slipping motion of these field lines leads to form an extended narrow magnetic
flux tube at high altitude. Because of the slip-running reconnection, we
conjecture that if energetic particles would be traveling through, or be
accelerated inside, the diffusion region, they would be successively injected
along continuously reconnecting field lines that are connected farther and
farther from the spine. At the scale of the full Sun, owing to the super-radial
expansion of field lines below 3 solar radii, such energetic particles could
easily be injected in field lines slipping over significant distances, and
could eventually reach the distant flux tube that is well-connected to the
Earth
Solar interacting protons versus interplanetary protons in the core plus halo model of diffusive shock acceleration and stochastic re-acceleration
With the first observations of solar γ-rays from the decay of pions, the relationship of protons producing ground level enhancements (GLEs) on the Earth to those of similar energies producing the γ-rays on the Sun has been debated. These two populations may be either independent and simply coincident in large flares, or they may be, in fact, the same population stemming from a single accelerating agent and jointly distributed at the Sun and also in space. Assuming the latter, we model a scenario in which particles are accelerated near the Sun in a shock wave with a fraction transported back to the solar surface to radiate, while the remainder is detected at Earth in the form of a GLE. Interplanetary ions versus ions interacting at the Sun are studied for a spherical shock wave propagating in a radial magnetic field through a highly turbulent radial ray (the acceleration core) and surrounding weakly turbulent sector in which the accelerated particles can propagate toward or away from the Sun. The model presented here accounts for both the first-order Fermi acceleration at the shock front and the second-order, stochastic re-acceleration by the turbulence enhanced behind the shock. We find that the re-acceleration is important in generating the γ-radiation and we also find that up to 10% of the particle population can find its way to the Sun as compared to particles escaping to the interplanetary space
Observations of Electrons from the Decay of Solar Flare Neutrons
We have found evidence for fluxes of energetic electrons in interplanetary
space on board the ISEE-3 spacecraft which we interpret as the decay products
of neutrons generated in a solar flare on 1980 June 21. The decay electrons
arrived at the s/c shortly before the electrons from the flare and can be
distinguished from the latter by their distinctive energy spectrum. The time
profile of the decay electrons is in good agreement with the results from a
simulation based on a scattering mean free path derived from a fit to the flare
electron data. The comparison with simultaneously observed decay protons and a
published direct measurement of high-energy neutrons places important
constraints on the parent neutron spectrum.Comment: 4 pages (postscript), accepted by Astrophysical Journal Letter
All-sky Galactic radiation at 45 MHz and spectral index between 45 and 408 MHz
Aims: We study the Galactic large-scale synchrotron emission by generating a
reliable all-sky spectral index map and temperature map at 45 MHz. Methods: We
use our observations, the published all-sky map at 408 MHz, and a
bibliographical compilation to produce a map corrected for zero-level offset
and extragalactic contribution. Results: We present full sky maps of the
Galactic emission at 45 MHz and the Galactic spectral index between 45 and 408
MHz with an angular resolution of 5\degs. The spectral index varies between 2.1
and 2.7, reaching values below 2.5 at low latitude because of thermal free-free
absorption and its maximum in the zone next to the Northern Spur.Comment: A&A accepte
The young active star SAO 51891 (V383 Lac)
Our aim is investigating surface inhomogeneities of the young late-type star
SAO51891, from photosphere to upper chromosphere, analyzing contemporaneous
high-resolution spectra and broad-band photometry. The FOCES@CAHA spectral
range is used to determine spectral classification and derive vsini and Vrad.
The Li abundance is measured to estimate the age. The BVRIJHKs bands are used
to construct the SED. The variations of our BV fluxes and Teff are used to
infer the presence of photospheric spots and observe their behavior over time.
The chromospheric activity is studied applying the spectral subtraction
technique to Halpha, CaII H&K, Heps, and CaII IRT lines. We find SAO51891 to be
a young K0-1V star with Li abundance close to the Pleiades upper envelope,
confirming its youth (~100 Myr), also inferred from its kinematical membership
to the Local Association. We detect no IR excess from SED analysis, and
rotational modulation of luminosity, Teff, CaII, and Heps total fluxes. A spot
model with two active regions, ~240 K cooler than the surrounding photosphere,
fits our light/Teff curves, and reproduces the small-amplitude Vrad variations.
The anti-correlation of light curves and chromospheric diagnostics indicates
plages spatially associated with spots. The large amplitude observed in the
Heps-flux curve suggests that this line is very sensitive to the plage
presence. Finally, SAO51891 is a young active star, lacking significant amounts
of circumstellar dust or any evidence for low mass companions. The spots turn
out to be larger and warmer than those in less active MS stars. The Vrad
variation produced by spots has an amplitude comparable with those induced by
Jupiter-mass planets orbiting close to the star. SAO51891 is a good example of
star where the detection of planets may be hampered by the high activity level.Comment: 16 pages, 12 figures, 7 tables, accepted by Astronomy and
Astrophysics; abstract here was shortene
Greenhouse gas emissions in The Netherlands 1990-2012 : National Inventory Report 2014
In 2012 is de totale uitstoot van broeikasgassen van Nederland, zoals CO2, methaan en lachgas, met ongeveer 1,7 procent gedaald ten opzichte van 2011. Deze daling komt vooral door een lager brandstofgebruik in de energie- en transportsector. Dit lijkt een gevolg van de economische recessie, waardoor emissies door elektriciteitsproductie en het wegtransport in Nederland zijn afgenomen. Cijfers De totale broeikasgasemissie wordt uitgedrukt in CO2-equivalenten en bedraagt in 2012 191,7 teragram (megaton of miljard kilogram) . Ten opzichte van de uitstoot in het Kyoto-basisjaar (213,2 Tg CO2-equivalenten) is dit een afname van ongeveer 10 procent. Het basisjaar, dat afhankelijk van het broeikasgas 1990 of 1995 is, dient voor het Kyoto-protocol als referentie voor de uitstoot van broeikasgassen. De uitstoot van de overige broeikasgassen zoals lachgas en methaan is sinds het basisjaar met 51 procent afgenomen. De CO2-uitstoot daarentegen is in deze periode met 4 procent gestegen. Landen zijn voor het Kyoto-protocol verplicht om de totale uitstoot van broeikasgassen op twee manieren te rapporteren: met en zonder het soort landgebruik en de verandering daarin. Dit is namelijk van invloed op de uitstoot van broeikasgassen. Voorbeelden zijn natuurontwikkeling (dat CO2 bindt) of ontbossing (waardoor CO2 wordt uitgestoten). In bovengenoemde getallen zijn deze zogeheten LULUCF-emissies (Land Use, Land Use Change and Forestry) niet meegenomen. Overige onderdelen inventarisatie Het RIVM stelt jaarlijks op verzoek van het Ministerie van Infrastructuur en Milieu (IenM) de inventarisatie van broeikasgasemissies op. De inventarisatie bevat trendanalyses om ontwikkelingen in de uitstoot van broeikasgassen tussen 1990 en 2012 te verklaren, en een analyse van de onzekerheid in deze getallen. Ook is aangegeven welke bronnen het meest aan deze onzekerheid bijdragen. Daarnaast biedt de inventarisatie documentatie van de gebruikte berekeningsmethoden, databronnen en toegepaste emissiefactoren. Met deze inventarisatie voldoet Nederland aan de nationale rapportageverplichtingen voor 2012 van het Klimaatverdrag van de Verenigde Naties (UNFCCC), van het Kyoto-Protocol en van het Bewakingsmechanisme Broeikasgassen van de Europese Unie.Total greenhouse gas emissions from the Netherlands in 2012 decreased by approximately 1.7 per cent, compared with 2011 emissions. This decrease is mainly the result of decreased fuel combustion in the Energy sector (increased electricity import) and in road transport. In 2012, total direct greenhouse gas emissions (excluding emissions from LULUCF - land use, land use change and forestry) in the Netherlands amounted to 191.7 Tg CO2 eq. This is approximately 10 per cent below the emissions in the base year (213.2 Tg CO2 eq.). The 51% reduction in the non-CO2 emissions in this period is counterbalanced by 4 per cent increase in CO2 emissions since 1990. This report documents the Netherlands' 2014 annual submission of its greenhouse gas emissions inventory in accordance with the guidelines provided by the United Nations Framework Convention on Climate Change (UNFCCC), the Kyoto Protocol and the European Union's Greenhouse Gas Monitoring Mechanism. The report comprises explanations of observed trends in emissions; a description of an assessment of key sources and their uncertainty; documentation of methods, data sources and emission factors applied; and a description of the quality assurance system and the verification activities performed on the data.Ministerie van I&
- …