DARCOF II. Danish research in Organic Food and Farming systems 2000-2005

The aim of this book is to present a comprehensive overview of the 41 research projects undertaken in the period 2000-2005 in the research programme DARCOF II.For each project there is a description of its background and objective in terms of which issues gave rise to the project and what the project aims to achieve. This is followed by a short description of the experiments or investigations that have been undertaken in the project. The general and applicable results derived from the project are finally described. For each project there is a reference to a project home page on www.darcof.dk. Via this page there is direct access to "Organic Eprints", which is the site containing all the project publications – both technical and scientific

Ultrasonic transducer with Gaussian radial pressure distribution

An ultrasonic transducer that produces an output that is a symmetrical function comprises a piezoelectric crystal with several concentric ring electrodes on one side of the crystal. A resistor network applies different amplitudes of an ac source to each of the several electrodes. A plot of the different amplitudes from the outermost electrode to the innermost electrode is the first half of a Gaussian function. Consequently, the output of the crystal from the side opposite the electrodes has a Gaussian profile

Phenotypic mixing and hiding may contribute to memory in viral quasispecies

Background. In a number of recent experiments with food-and-mouth disease virus, a deleterious mutant, was found to avoid extinction and remain in the population for long periods of time. This observation was called quasispecies memory. The origin of quasispecies memory is not fully understood. Results. We propose and analyze a simple model of complementation between the wild type virus and a mutant that has an impaired ability of cell entry. The mutant will go extinct unless it is recreated from the wild type through mutations. However, under phenotypic mixing-and-hiding as a mechanism of complementation, the time to extinction in the absence of mutations increases with increasing multiplicity of infection (m.o.i.). The mutant's frequency at equilibrium under selection-mutation balance also increases with increasing m.o.i. At high m.o.i., a large fraction of mutant genomes are encapsidated with wild-type protein, which enables them to infect cells as efficiently as the wild type virions, and thus increases their fitness to the wild-type level. Moreover, even at low m.o.i. the equilibrium frequency of the mutant is higher than predicted by the standard quasispecies model, because a fraction of mutant virions generated from wild-type parents will also be encapsidated by wild-type protein. Conclusions. Our model predicts that phenotypic hiding will strongly influence the population dynamics of viruses, particularly at high m.o.i., and will also have important effects on the mutation--selection balance at low m.o.i. The delay in mutant extinction and increase in mutant frequencies at equilibrium may, at least in part, explain memory in quasispecies populations.Comment: 10 pages pdf, as published by BM

A Spitzer Study of Interacting Luminous and Ultra-Luminous Infrared Galaxies

We conducted a Spitzer Space Telescope survey of 28 Luminous (11 < log(LIR/L_odot) < 12, LIRGs) and Ultra-Luminous Infrared Galaxies (log(LIR/L_odot) > 12, ULIRGs). Many of these galaxies are found in pairs or associations and are powered by either nuclear activity or starformation (Sanders & Mirabel 1996). Our main goal is to understand the relative importance of starbursts and AGNs in interacting systems. Is the frequency of AGN and starbursts in these interacting galaxies related to their luminosities? What is the importance of the merger stage and the frequency of AGNs? We present our conclusions and diagnostic diagrams based in the observed near infrared lines and compare to studies based solely in optical data.Comment: 3 pages, 2 figures, to appear in the Spectral Energy Distribution of Galaxies (SED2011) conference proceedings, Preston, UK, 201

Variability Abstractions: Trading Precision for Speed in Family-Based Analyses (Extended Version)

Family-based (lifted) data-flow analysis for Software Product Lines (SPLs) is capable of analyzing all valid products (variants) without generating any of them explicitly. It takes as input only the common code base, which encodes all variants of a SPL, and produces analysis results corresponding to all variants. However, the computational cost of the lifted analysis still depends inherently on the number of variants (which is exponential in the number of features, in the worst case). For a large number of features, the lifted analysis may be too costly or even infeasible. In this paper, we introduce variability abstractions defined as Galois connections and use abstract interpretation as a formal method for the calculational-based derivation of approximate (abstracted) lifted analyses of SPL programs, which are sound by construction. Moreover, given an abstraction we define a syntactic transformation that translates any SPL program into an abstracted version of it, such that the analysis of the abstracted SPL coincides with the corresponding abstracted analysis of the original SPL. We implement the transformation in a tool, reconfigurator that works on Object-Oriented Java program families, and evaluate the practicality of this approach on three Java SPL benchmarks.Comment: 50 pages, 10 figure

An overlooked family-group name among bees: Availability of Coelioxoidini (Hymenoptera: Apidae)

Recent phylogenetic analysis of the family Apidae has applied the tribal name Coelioxoidini to the distinctive genus Coelioxoides Cresson, which has been thought to be related to Tetrapedia Klug.&nbsp; However, the nomenclatural status of such a family-group name has not yet been assessed.&nbsp; Herein, we determine that this family-group name is available and discuss its authorship and proposal date

Are the self-employed really jacks-of-all-trades? Testing the assumptions and implications of Lazear's theory of entrepreneurship with German data

Using a large representative German data set and various concepts of self-employment, this paper tests the 'jack-of-all-trades' view of entrepreneurship by Lazear (AER 2004). Consistent with its theoretical assumptions we find that self-employed individuals perform more tasks and that their work requires more skills than that of paid employees. In contrast to Lazear's assumptions, however, self-employed individuals do not just need more basic but also more expert skills than employees. Our results also provide only very limited support for the idea that human capital investment patterns differ between those who become self-employed and those ending up in paid employment. -- Unter Verwendung eines großen, repräsentativen Datensatzes für Deutschland und verschiedener Abgrenzungen der Selbständigkeit überprüft diese Arbeit die 'jack-of-all-trades'-Sicht des Unternehmertums von Lazear (AER 2004). In Übereinstimmung mit ihren theoretischen Annahmen finden wir, dass Selbständige mehr verschiedene Tätigkeiten ausüben und Kenntnisse aus mehr verschiedenen Gebieten benötigen als nicht-selbständige Arbeitnehmer. Im Gegensatz zu Lazear's Annahmen benötigen Selbständige allerdings nicht nur mehr Grundkenntnisse sondern auch mehr Fachkenntnisse als Nicht-Selbständige. Unsere Ergebnisse liefern zudem nur wenig Unterstützung für die Behauptung, dass sich die Muster der Humankapitalaneignung zwischen Selbstständigen und abhängig beschäftigten Arbeitnehmern sichtbar unterscheiden.entrepreneurship,self-employed,Germany