Complexity and trust – experiences from local Danish Food Communities

Generally food consumers in Denmark do not trust the food production and distribution systems and the management of risk related to food consumption has become part of the daily life of many (Halkier & Holm, 2004). This paper explores how relations of trust are formed in two local Danish Food Communities (Fødevarefællesskaber) in Aarhus and Copenhagen. Food Communities are communities of consumers organized around the provision of local fresh vegetables directly from local producers. The Food Communities, together with local farmers, share the responsibilities, normally carried out by other market actors, such as logistics, sale and price formation. The vegetables are sold to the members of the community, at a relatively low price, if they take part in the duty work related to the food provisioning. The community functions despite no binding or long term agreements are made between the communities and the producers. The aim of this paper is to evaluate what role trust plays in order for the communities to function. Focus is given to 1) the mechanisms that create and maintain trust between the actors and 2) the challenges that the relations of trust are exposed to and 3) how the communities are dealing with these challenges

AME - Asteroseismology Made Easy. Estimating stellar properties by use of scaled models

We present a new method to obtain stellar properties for stars exhibiting solar-like oscillations in an easy, fast, and transparent way. The method, called Asteroseismology Made Easy (AME), can determine stellar masses, mean-densities, radii, and surface gravities, as well as estimate ages. In this writing we present AME as a visual and powerful tool which could be useful; in particular in the light of the large number of exoplanets being found. AME consists of a set of figures from which the stellar parameters are deduced. These figures are made from a grid of stellar evolutionary models that cover masses ranging from 0.7 Msun to 1.6 Msun in steps of 0.1 Msun and metallicities in the interval -0.3 dex <= [Fe/H] <= +0.3 dex in increments of 0.1 dex. The stellar evolutionary models are computed using the Modules for Experiments in Stellar Astrophysics (MESA) code with simple input physics. We have compared the results from AME with results for three groups of stars; stars with radii determined from interferometry (and measured parallaxes), stars with radii determined from measurements of their parallaxes (and calculated angular diameters), and stars with results based on the modelling of their individual oscillation frequencies. We find that a comparison of the radii from interferometry to those from AME yield a weighted mean of the fractional differences of just 2%. This is also the level of deviation that we find when we compare the parallax-based radii to the radii determined from AME. The comparison between independently determined stellar parameters and those found using AME show that our method can provide reliable stellar masses, radii, and ages, with median uncertainties in the order of 4%, 2%, and 25% respectively.Comment: 18 pages, 25 figures. To be published in Astronomy & Astrophysic

Evidence for Granulation and Oscillations in Procyon from Photometry with the WIRE satellite

We report evidence for the granulation signal in the star Procyon A, based on two photometric time series from the star tracker on the WIRE satellite. The power spectra show evidence of excess power around 1 milliHz, consistent with the detection of p-modes reported from radial velocity measurements. We see a significant increase in the noise level below 3 milliHz, which we interpret as the granulation signal. We have made a large set of numerical simulations to constrain the amplitude and timescale of the granulation signal and the amplitude of the oscillations. We find that the timescale for granulation is T(gran) = 750(200) s, the granulation amplitude is 1.8(0.3) times solar, and the amplitude of the p-modes is 8(3) ppm. We found the distribution of peak heights in the observed power spectra to be consistent with that expected from p-mode oscillations. However, the quality of the data is not sufficient to measure the large separation or detect a comb-like structure, as seen in the p-modes of the Sun. Comparison with the recent negative result from the MOST satellite reveal that the MOST data must have an additional noise source that prevented the detection of oscillations.Comment: 23 pages, 12 figures, submitted to ApJ; v2 revisions: one reference corrected and a comment in Figure 7 correcte

A public summer school on astronomy in Denmark: experience from the course in 2002, 2003 and 2004

International audienceDuring the summers of 2002, 2003 and 2004 a one-week public course on Astronomy took place at Silkeborg Folk High School in central Jutland, Denmark. The aim of the course was to offer a possibility for students to meet research scientists and discuss central scientific questions and their answers. Researchers from the Department of Physics and Astronomy at Aarhus University in Denmark took an active part in running this summer school and the course could also be seen as a part of the Department's general public outreach activities. The main aim of those activities is to: (1) show why research is important, (2) give students and children the possibility to meet people that do research, and (3) present authentic role models

Measuring stellar oscillations using equivalent widths of absorption lines

Kjeldsen et al. (1995, AJ 109, 1313; astro-ph/9411016) have developed a new technique for measuring stellar oscillations and claimed a detection in the G subgiant eta Boo. The technique involves monitoring temperature fluctuations in a star via their effect on the equivalent width of Balmer lines. In this paper we use synthetic stellar spectra to investigate the temperature dependence of the Balmer lines, Ca II, Fe I, the Mg b feature and the G~band. We present a list of target stars likely to show solar-like oscillations and estimate their expected amplitudes. We also show that centre-to-limb variations in Balmer-line profiles allow one to detect oscillation modes with l<=4, which accounts for the detection by Kjeldsen et al. of modes with degree l=3 in integrated sunlight.Comment: MNRAS (accepted); 7 pages, LaTeX with necessary style file and PostScript figures in a single uuencoded Z-compressed .tar fil

Search for sdB/WD pulsators in the Kepler FOV

In this article we present the preliminary results of an observational search for subdwarf B and white dwarf pulsators in the Kepler field of view, performed using the DOLORES camera attached to the 3.6m Telescopio Nazionale Galileo (TNG).Comment: Communications in Asteroseismology, in press; 2 pages, 1 figur