592 research outputs found
The synthetic substrate succinyl(carbadethia)-CoA generates cob(II)alamin on adenosylcobalamin-dependent methylmalonyl-CoA mutase
Structure of the stationary phase survival protein YuiC from B.subtilis
- Background: Stationary phase survival proteins (Sps) were found in Firmicutes as having
analogous domain compositions, and in some cases genome context, as the resuscitation
promoting factors of Actinobacteria, but with a different putative peptidoglycan cleaving
domain.
- Results: The first structure of a Firmicute Sps protein YuiC from B. subtilis, is found to be a
stripped down version of the cell-wall peptidoglycan hydrolase MltA. The YuiC structures are of
a domain swapped dimer, although some monomer is also found in solution. The protein
crystallised in the presence of pentasaccharide shows a 1,6-anhydrodisaccharide sugar product,
indicating that YuiC cleaves the sugar backbone to form an anhydro product at least on lengthy
incubation during crystallisation.
- Conclusions:
The structural simplification of MltA in Sps proteins is analogous to that of the resuscitation
promoting factor domains of Actinobacteria, which are stripped down versions of lysozyme and
soluble lytic transglycosylase proteins
Low‐temperature growth of high resistivity GaAs by photoassisted metalorganic chemical vapor deposition
We report the photoassisted low‐temperature (LT) metalorganic chemical vapor deposition (MOCVD) of high resistivity GaAs. The undoped as‐grown GaAs exhibits a resistivity of ∼106 Ω cm, which is the highest reported for undoped material grown in the MOCVD environment. Photoassisted growth of doped and undoped device quality GaAs has been achieved at a substrate temperature of 400 °C in a modified atmospheric pressure MOCVD reactor. By using silane as a dopant gas, the LT photoassisted doped films have high levels of doping and electron mobilities comparable to those achieved by MOCVD for growth temperatures, Tg≳600 °C
Kinetics of reduction of FeO from slag by graphite and coal chars
The rates of reduction of FeO from iron-saturated FeO-CaO-Al2O3-SiO2 slags by graphite, coke, bituminous coal and anthracitic coal chars at temperatures in the range 1 673-1873 K have been measured using a sessile drop technique. The extents of reaction were determined using EPMA analysis of quenched samples, and on line gas analysis using a quadrupole mass spectrometer. The reaction rates have been shown to be dependent critically on carbon type. For the reaction geometry used in this investigation the reduction rates of graphite and coke are observed to be faster than with coal chars. This unexpected finding is shown to be associated with differences in the dominant chemical and mass transfer mechanisms occurring at the reaction interface. High reaction rates are observed to occur with the formation of liquid Fe-C alloy product and the associated gasification of carbon from the alloy. The rates of reduction by coal chars are determined principally by the chemical reaction at the carbon/gas interface and slag phase mass transfer
Have Anglo-Saxon concepts really influenced the development of European qualifications policy?
This paper considers how far Anglo-Saxon conceptions of have influenced European Union vocational education and training policy, especially given the disparate approaches to VET across Europe. Two dominant approaches can be identified: the dual system (exemplified by Germany); and output based models (exemplified by the NVQ ‘English style’). Within the EU itself, the design philosophy of the English output-based model proved in the first instance influential in attempts to develop tools to establish equivalence between vocational qualifications across Europe, resulting in the learning outcomes approach of the European Qualifications Framework, the credit-based model of European VET Credit System and the task-based construction of occupation profiles exemplified by European Skills, Competences and Occupations. The governance model for the English system is, however, predicated on employer demand for ‘skills’ and this does not fit well with the social partnership model encompassing knowledge, skills and competences that is dominant in northern Europe. These contrasting approaches have led to continual modifications to the tools, as these sought to harmonise and reconcile national VET requirements with the original design. A tension is evident in particular between national and regional approaches to vocational education and training, on the one hand, and the policy tools adopted to align European vocational education and training better with the demands of the labour market, including at sectoral level, on the other. This paper explores these tensions and considers the prospects for the successful operation of these tools, paying particular attention to the European Qualifications Framework, European VET Credit System and European Skills, Competences and Occupations tool and the relationships between them and drawing on studies of the construction and furniture industries
Landscape science: a Russian geographical tradition
The Russian geographical tradition of landscape science (landshaftovedenie) is analyzed with particular reference to its initiator, Lev Semenovich Berg (1876-1950). The differences between prevailing Russian and Western concepts of landscape in geography are discussed, and their common origins in German geographical thought in the late nineteenth and early twentieth centuries are delineated. It is argued that the principal differences are accounted for by a number of factors, of which Russia's own distinctive tradition in environmental science deriving from the work of V. V. Dokuchaev (1846-1903), the activities of certain key individuals (such as Berg and C. O. Sauer), and the very different social and political circumstances in different parts of the world appear to be the most significant. At the same time it is noted that neither in Russia nor in the West have geographers succeeded in specifying an agreed and unproblematic understanding of landscape, or more broadly in promoting a common geographical conception of human-environment relationships. In light of such uncertainties, the latter part of the article argues for closer international links between the variant landscape traditions in geography as an important contribution to the quest for sustainability
British Thoracic Society Guideline for oxygen use in adults in healthcare and emergency settings
Progress in EU-DEMO in-vessel components integration
In the EU DEMO design (Romanelli, 2012; Federici et al., 2014), due to the large number of complex systems inside the tokamak vessel it is of vital importance to address the in-vessel integration at an early stage in the design process. In the EU DEMO design, after a first phase in which the different systems have been developed independently based on the defined baseline DEMO configuration, an effort has been made to define the interface requirements and to propose the strategies for the mechanical integration of the auxiliary heating and fuelling systems into the Vacuum Vessel and the Breeding Blanket. This work presents the options studied, the engineering solutions proposed, and the issues highlighted for the mechanical in-vessel integration of the DEMO fuelling lines, auxiliaries heating systems, and diagnostics
The UK's exit charge from the EU: insights from modes of accounting
Whatever the final charge on the UK for leaving the EU, the money itself is relatively marginal to the former's public finances. However, this charge is politically sensitive and financially aggravating during one of the longest periods of fiscal austerity in the UK's history. The ways in which leaving is conceptualized have implications for any continuing financial obligations that must be managed within the context of fiscal austerity and political uncertainty. Yet, leaving the EU is a unique transaction: it is not analogous, for example, to a divorce settlement, the leaving of a club, the termination of a commercial contract, the leaving of a treaty‐based international organization, or secession from a state. Analysing the formulation of the charge in terms of the four modes of government accounting—financial reporting, statistical accounting, budgeting, and fiscal sustainability projections—enhances its fiscal transparency. It evidences not only the weakness and inconsistency of the UK's negotiating position but also the dominance in EU thinking of the short‐term budgetary calculations of the 2014–20 Multiannual Financial Framework over its long‐term sustainability without a large net contributor. The final amount paid by the UK will depend on the resolution of competing perspectives as well as on liabilities and contingent liabilities associated with the increasingly complex EU financial architecture
Disentangling the Relative Importance of Changes in Climate and Land-Use Intensity in Driving Recent Bird Population Trends
Threats to biodiversity resulting from habitat destruction and deterioration have been documented for many species, whilst climate change is regarded as increasingly impacting upon species' distribution and abundance. However, few studies have disentangled the relative importance of these two drivers in causing recent population declines. We quantify the relative importance of both processes by modelling annual variation in population growth of 18 farmland bird species in the UK as a function of measures of land-use intensity and weather. Modelled together, both had similar explanatory power in accounting for annual fluctuations in population growth. When these models were used to retrodict population trends for each species as a function of annual variation in land-use intensity and weather combined, and separately, retrodictions incorporating land-use intensity were more closely linked to observed population trends than retrodictions based only on weather, and closely matched the UK farmland bird index from 1970 onwards. Despite more stable land-use intensity in recent years, climate change (inferred from weather trends) has not overtaken land-use intensity as the dominant driver of bird populations
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