Flickr Images: What & Why Museums Share

This paper presents the results of a study which explored the use of Flickr by cultural heritage institutions. The study examined two aspects of museums’ use of Flickr: the content of images posted by museums, and the reasons behind sharing their images to the social media site. Images were categorized by the researchers into nine classes based on their visible content, and a brief questionnaire was used to gather data about the image sharing process from museum personnel. The findings reveal that imagery of people visiting the museum and taking part in museum events predominated in the total number of images posted by museums (54% of the total). The images posted to Flickr were most often selected by a single individual at the institution. The particular images posted to Flickr were chosen for a variety of reasons, the most common of these being that they were newsworthy recent events at the museum (e.g. openings, exhibitions, lectures, etc.), or that the staff found the images to have strong affective characteristics. In the responses from museum staff regarding the motivations behind posting the images to Flickr two replies were most commonly given: to provide access to the images, and to take advantage of the technical benefits provided by the photo-sharing service

The Quantum Skyrmion in Representations of General Dimension

The representations of general dimension are constructed for the $SU(2)$ Skyrme model, treated quantum mechanically {\it ab initio. } This quantum Skyrme model has a negative mass term correction, that is not present in the classical Hamiltonian. The magnitude of the quantum mechanical mass correction increases with the dimension of the representation of the $SU(2)$ group. In the case of a 5-dimensional representation it is possible to obtain satisfactory predictions for the nucleon mass with the empirical value for the pion decay constant.Comment: Plain latex, 15 page

Symbiotic N2 fixation by soybean in organic and conventional cropping systems estimated by 15N dilution and 15N natural abundance

Nitrogen (N) is often the most limiting nutrient in organic cropping systems. N2 fixing crops present an important option to improve N supply and to maintain soil fertility. In a field experiment, we investigated whether the lower N fertilization level and higher soil microbial activity in organic than conventional systems affected symbiotic N2 fixation by soybean (Glycine max, var. Maple Arrow) growing in 2004 in plots that were since 1978 under the following systems: bio-dynamic (DYN); bio-organic (ORG); conventional with organic and mineral fertilizers (CON); CON with exclusively mineral fertilizers (MIN); non-fertilized control (NON). We estimated the percentage of legume N derived from the atmosphere (%Ndfa) by the natural abundance (NA) method. For ORG and MIN we additionally applied the enriched 15N isotope dilution method (ID) based on residual mineral and organic 15N labeled fertilizers that were applied in 2003 in microplots installed in ORG and MIN plots. These different enrichment treatments resulted in equal %Ndfa values. The %Ndfa obtained by NA for ORG and MIN was confirmed by the ID method, with similar variation. However, as plant growth was restricted by the microplot frames the NA technique provided more accurate estimates of the quantities of symbiotically fixed N2 (Nfix). At maturity of soybean the %Ndfa ranged from 24 to 54%. It decreased in the order ORG>CON>DYN>NON>MIN, with significantly lowest value for MIN. Corresponding Nfix in above ground plant material ranged from 15 to 26g Nm-2, with a decreasing trend in the order DYN=ORG>CON>MIN>NON. For all treatments, the N withdrawal by harvested grains was greater than Nfix. This shows that at the low to medium %Ndfa, soybeans did not improve the N supply to any system but removed significant amounts of soil N. High-soil N mineralization and/or low-soil P availability may have limited symbiotic N2 fixatio

Nitrogen use efficiency of 15N-labelled sheep manure and mineral fertiliser applied to microplots in long-term organic and conventional cropping systems

Nitrogen (N) utilisation by crops has to be improved to minimize losses to the environment. We investigated N use efficiency of animal manure and mineral fertiliser and fate of fertiliser N not taken up by crops in a conventional (CONMIN) and a bio-organic (BIOORG) cropping system of a long-term field experiment over three vegetation periods (winter wheat-soybean-maize). Microplots planted with wheat received a single application of 15N-labelled slurries (either urine or faeces labelled) or mineral fertiliser. At the end of each vegetation period we tested whether higher microbial activity and larger microbial biomass in BIOORG than CONMIN soils, and lower long-term N input level in BIOORG, affected use efficiency and fate of fertiliser N not taken up by crops. Recovery of 15N in wheat was 37%, 10% and 47% from urine, faeces and mineral fertiliser, respectively, and decreased strongly in the residual years. In total 41%, 15% and 50% of 15N applied as urine, faeces and mineral fertiliser was recovered by the three crops. 15N recovered from originally applied urine, faeces and mineral fertiliser in the topsoil (0-18cm) at the end of the third vegetation period was 19%, 25% and 20%, respectively. Of urine-, faeces- and mineral fertiliser-15N, 40%, 61% and 29%, respectively, was not recovered by the three crops and in topsoil suggesting significant transport of 15N-labelled components to deeper soil layers. CONMIN and BIOORG differed neither in fertiliser N use efficiency by crops nor in 15N recovery in soil indicating insignificant difference in the turnover and utilization of the applied manure nitrogen in the conventional and the bio-organic cropping system

Nachweis der Ermüdungssicherheit von Brücken – Teil 1: Veranlassung, Ziel und Messkonzept des Monitoring-Projekts „Bahnbrücke Eglisau"

Durch steigende Anforderungen des modernen Bahnverkehrs (vor allem durch höhere Achslasten und Zugfrequenzen) werden Bahnbrücken immer stärker beansprucht. Entsprechend muss die Trag- und Ermüdungssicherheit dieser Brücken nachgewiesen werden. Dies erfolgt über eine so genannte Aktualisierung, indem die effektiv auftretende Beanspruchung des Brückentragwerks genau ermittelt wird. Im Rahmen eines Pilotprojekts werden zurzeit zerstörungsfreie, statische und dynamische Belastungsversuche an der Bahnbrücke Eglisau, Schweiz, durchgeführt, um Informationen zu erhalten, auf deren Basis zuverlässige Aussagen zur Tragsicherheit und Ermüdungssicherheit gemacht werden sollen. Im laufenden Bahnbetrieb ist die eingleisig befahrene Bahnbrücke schwer zugänglich, weshalb die Langzeitmessungen mit Hilfe eines festinstallierten, vollautomatischen Bauwerk-Monitoring-Systems (swissMon) durchgeführt werden. Mit Hilfe dieses Systems können beliebig viele, unterschiedliche Messsensoren zyklisch oder getriggert durch das Überfahren eines Zuges betrieben werden. Die mit swissMon gewonnen Daten sind eine verlässliche Grundlage für weitere Analysen und Modellrechnungen und unterstützen die beteiligten Tragwerksingenieure insbesondere bei der Beurteilung der Ermüdungssicherhei

Characterisation of the mycobacterial NER system reveals novel functions of uvrD1 helicase

In this study, we investigated the role of the nucleotide excision repair (NER) pathway in mycobacterial DNA repair. Mycobacterium smegmatis lacking the NER excinuclease component uvrB, the helicase uvrD1 and a double knock-out lacking both proteins were constructed and their sensitivity to a series of DNA damaging agents wa analysed. As anticipated, the mycobacterial NER system was shown to be involved in the processing of bulky DNA adducts and inter-strand cross-links. In addition, it could be shown to exert a protective effect against oxidising and nitrosating agents. Interestingly, inactivation of uvrB and uvrD1 significantly increased marker integration frequencies in gene conversion assays. This implies that in mycobacteria, which lack the postreplicative mismatch repair system, NER, and particularly the UvrD1 helicase, is involved in the processing of a subset of recombination-associated mismatches

Nitrogen budgets and soil nitrogen stocks of organic and conventional cropping systems: how reconcile efficiency and sustainability of nitrogen use?

Organic and conventional cropping systems differ in the nature and amounts of nitrogen (N) inputs, which may affect efficiency and sustainability of N use. In the DOK (bio-Dynamic, bio-Organic, Konventionell) field experiment, organic and conventional cropping systems have been compared since 1978 at two fertilization levels (with level 2 being typical for the respective system and level 1 receiving half of this dose)

Characterization of fecal nitrogen forms produced by a sheep fed with 15N labeled ryegrass

Little is known about nitrogen (N) forms in ruminant feces, although this information is important to understand N dynamics in agro-ecosystems. We fed 15N labeled ryegrass hay to a sheep and collected 15N labeled feces. Nitrogen forms in the feces were characterized by chemical extractions, solid-state cross polarization 15N nuclear magnetic resonance spectroscopy (SS CP/MAS 15N NMR) and Curie-point pyrolysis-gas chromatography/mass spectrometry (Cp Py-GC/MS). A 4months incubation experiment was conducted to assess N release from the feces. Half of the fecal N could be ascribed to bacterial and endogenous debris and a third to undigested dietary N. About a tenth of the fecal N was mineralized during the incubation experiment. The 15N abundance of nitrate released during the incubation remained constant and close to the 15N abundance of the total feces N. The NMR analysis of the feces showed that most of the N was present in proteins, while some was present as heterocyclic N, amino acids and ammonium. The Cp Py-GC/MS analysis confirmed the presence of proteins, amino acids and heterocyclic N in the feces. Comparing these results to those obtained from the 15N labeled hay suggests that some N compounds present in the plant were not digested by the animal, and that the animal excreted de novo synthesized N compounds. The low content in ammonium and amino acids, the low rate of N release from these feces during the incubation and the relatively high fecal protein content, particularly the hard to mineralize undigested and microbially bound forms, can explain the low transfer of N from these feces to crops observed in a previous wor

Octet, decuplet and antidecuplet magnetic moments in the chiral quark soliton model revisited

We reanalyse the magnetic moments of the baryon octet, decuplet, and antidecuplet within the framework of the chiral quark-soliton model, with SU(3) symmetry breaking taken into account. We consider the contributions of the mixing of higher representations to the magnetic moment operator arising from the SU(3) symmetry breaking. Dynamical parameters of the model are fixed by experimental data for the magnetic moments of the baryon octet and from the masses of the octet, decuplet and of $\Theta^{+}$. The magnetic moment of $\Theta^{+}$ depends rather strongly on the pion-nucleon sigma term and reads $-1.19 {\rm n.m.}$ to $-0.33 {\rm n.m.}$ for $\Sigma_{\pi N} = 45$ and 75 MeV respectively. The recently reported mass of $\Xi^{--}_{\bar{10}}(1862)$ is compatible with $\Sigma_{\pi N} = 73$ MeV. As a byproduct the strange magnetic moment of the nucleon is obtained with a value of $\mu^{(s)}_N =+0.39$ n.m.Comment: RevTeX is used. 12 pages, 3 figures, final version for publication in Phys. Rev.