Interview Study on the Agile Development of Mechatronic Systems

In order to be as responsive as possible to changes in the dynamic context of mechatronic system development, companies are increasingly integrating agile approaches into their development processes. They are confronted with the challenges of adapting approaches that originate in software development to the conditions of physical development, without neglecting the experiences gained over many years regarding product and process knowledge. In addition, agile development approaches must be integrated into existing processes through a systematic implementation strategy. In order to gain an initial understanding of the current situation in mechatronic companies with regard to agile development approaches, an interview study was conducted with 18 participants from real development practice. This could show that the companies in mechatronic system development are currently at the beginning of agile transformation and need approaches that are modelled on the basis of real development projects and are best possible tailored to the needs of these companies through a clear technical orientation. The findings gained are not universally valid, but represent a basis for further research work

Genome sequence of Desulfurella amilsii strain TR1 and comparative genomics of Desulfurellaceae family

The acidotolerant sulfur reducer Desulfurella amilsii was isolated from sediments of Tinto river, an extremely acidic environment. Its ability to grow in a broad range of pH and to tolerate certain heavy metals offers potential for metal recovery processes. Here we report its high-quality draft genome sequence and compare it to the available genome sequences of other members of Desulfurellaceae family: D. acetivorans, D. multipotens, Hippea maritima, H. alviniae, H. medeae and H. jasoniae. For most species, pairwise comparisons for average nucleotide identity (ANI) and in silico DNA-DNA hybridization (DDH) revealed ANI values from 67.5 to 80% and DDH values from 12.9 to 24.2%. D. acetivorans and D. multipotens, however, surpassed the estimated thresholds of species definition for both DDH (98.6%) and ANI (88.1%). Therefore, they should be merged to a single species. Comparative analysis of Desulfurellaceae genomes revealed different gene content for sulfur respiration between Desulfurella and Hippea species. Sulfur reductase is only encoded in D. amilsii, in which it is suggested to play a role in sulfur respiration, especially at low pH. Polysulfide reductase is only encoded in Hippea species; it is likely that this genus uses polysulfide as electron acceptor. Genes encoding thiosulfate reductase are present in all the genomes, but dissimilatory sulfite reductase is only present in Desulfurella species. Thus, thiosulfate respiration via sulfite is only likely in this genus. Although sulfur disproportionation occurs in Desulfurella species, the molecular mechanism behind this process is not yet understood, hampering a genome prediction. The metabolism of acetate in Desulfurella species can occur via the acetyl-CoA synthetase or via acetate kinase in combination with phosphate acetyltransferase, while in Hippea species, it might occur via the acetate kinase. Large differences in gene sets involved in resistance to acidic conditions were not detected among the genomes. Therefore, the regulation of those genes, or a mechanism not yet known, might be responsible for the unique ability of D. amilsii. This is the first report on comparative genomics of sulfur-reducing bacteria, which is valuable to give insight into this poorly understood metabolism, but of great potential for biotechnological purposes and of environmental significance.The authors thank CNPq (Conselho Nacional de Desenvolvimento Cientifiìco e Tecnoloìgico),organization of the Brazilian Government for supporting the doctoral study program for the development of Science and Technology. Research of IS-A and AM Stams is financed by ERC grant project 323009, and Gravitation grant project 024.002.002 fromTheNetherlands Ministry of Education, Culture and Science. Thanks to Bastian Hornung for the bioinformatics support and to Robert Smith for the English revision.info:eu-repo/semantics/publishedVersio

Activation of Methanogenesis in Arid Biological Soil Crusts Despite the Presence of Oxygen

Methanogenesis is traditionally thought to occur only in highly reduced, anoxic environments. Wetland and rice field soils are well known sources for atmospheric methane, while aerated soils are considered sinks. Although methanogens have been detected in low numbers in some aerated, and even in desert soils, it remains unclear whether they are active under natural oxic conditions, such as in biological soil crusts (BSCs) of arid regions. To answer this question we carried out a factorial experiment using microcosms under simulated natural conditions. The BSC on top of an arid soil was incubated under moist conditions in all possible combinations of flooding and drainage, light and dark, air and nitrogen headspace. In the light, oxygen was produced by photosynthesis. Methane production was detected in all microcosms, but rates were much lower when oxygen was present. In addition, the δ13C of the methane differed between the oxic/oxygenic and anoxic microcosms. While under anoxic conditions methane was mainly produced from acetate, it was almost entirely produced from H2/CO2 under oxic/oxygenic conditions. Only two genera of methanogens were identified in the BSC-Methanosarcina and Methanocella; their abundance and activity in transcribing the mcrA gene (coding for methyl-CoM reductase) was higher under anoxic than oxic/oxygenic conditions, respectively. Both methanogens also actively transcribed the oxygen detoxifying gene catalase. Since methanotrophs were not detectable in the BSC, all the methane produced was released into the atmosphere. Our findings point to a formerly unknown participation of desert soils in the global methane cycle

A quick guide to shaping London : design for London

1 archivo PDF (Tipo: Presentación) : principalmente ilustraciones en color ; 122 diapositivas.Se presentan imágenes de la ciudad de Londres en el presente, se calcula el crecimiento demográfico para dentro de quince años, y se proponen acciones a llevar a cabo hoy para lograr una ciudad sustentable, buscando oportunidades y rediseñando los espacios. SUISE