810 resultados para Koch, Geoff
Resumo:
The antioxidant capacity of some herbs used in dietology practice was determined by the DPPH free radical method, which was calibrated with ascorbic acid. Partially hydrophilic phenolic compounds are the most active compounds in plants, and therefore water was used as the extraction agent. Besides antioxidant capacity, the content of total phenolic compounds was also measured and a strong correlation between these two variables was found. The extracts of lemon balm (Melissa officinalis L.), peppermint (Mentha x piperita L.), oregano (Origanum vulgare L.), Greek oregano (Origanum heracleoticum L.), sage (Salvia officinalis L.) and winter savory (Satureja montana L.) showed very significant activity. It was comparable with the activity of green tea in the case of oregano and peppermint. Lower activity was observed in the case of rosemary (Rosmarinus officinalis L.), marjoram (Majorana hortensis), hyssop (Hyssopus officinalis L.), sweet basil (Ocimum basilicum), and lovage (Levisticum officinale Koch.). The inhibitory activity of the herb extracts was monitored also during the autooxidation of lard. Very high antioxidant capacity was observed mainly in sage samples, but also in marjoram and Greek oregano. The extracts of peppermint, oregano, rosemary, winter savory, lemon balm and hyssop showed middle activity comparable to that of alpha-tocopherol. The antioxidant capacity of sweet basil and lovage was insignificant.
Resumo:
In this article Geoff Tennant puts forward a range of reasons for using mathematical notation, emphasising the need to allow children learning it time and space to come to terms with it. Examples are given in furthering the argument that the time to introduce notation is after the concept is already fully understood.
Resumo:
In this article Geoff Tennant summarises the first half of Imre Lakatos's seminal 1976 book, "Proofs and refutations: the logic of mathematical discovery". Implications are drawn for the classroom treatment of proof.
Resumo:
We are studying two enzymes from the shikimate pathway, dehydroquinate synthase (DHQS) and 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). Both enzymes have been the subject of numerous studies to elucidate their reaction mechanisms. Crystal structures of DHQS and EPSPS in the presence and absence of substrates, cofactors and/or inhibitors are now available. These structures reveal movements of domains, rearrangements of loops and changes in side-chain positions necessary for the formation of a catalytically competent active site. The potential for using complementary small-angle X-ray scattering (SAXS) studies to confirm the presence of these structural differences in solution has also been explored. Comparative analysis of crystal structures, in the presence and absence of ligands, has revealed structural features critical for substrate-binding and catalysis. We have also analysed these structures by generating GRID energy maps to detect favourable binding sites. The combination of X-ray crystallography, SAXS and computational techniques provides an enhanced analysis of structural features important for the function of these complex enzymes.
Resumo:
This paper argues that early childhood education and care (ECEC) has a legitimate aspiration to be a 'caring profession' like others such as nursing or social work, defined by a moral purpose. For example, practitioners often draw on an ethic of care as evidence of their professionalism. However, the discourse of professionalism in England completely excludes the ethical vocabulary of care. Nevertheless, it necessarily depends on gendered dispositions towards emotional labour, often promoted by training programmes as 'professional' demeanours. Taking control of the professionalisation agenda therefore requires practitioners to demonstrate a critical understanding of their practice as 'emotion work'. At the same time, reconceptualising practice within a political ethic of care may allow the workforce, and new trainees in particular, to champion 'caring' as a sustainable element of professional work, expressed not only in maternal, dyadic key-working but in advocacy for care as a social principle.
Resumo:
Not surprisingly housing researchers and practitioners frequently call for more resources to be devoted to housing. But governments in recent years have devoted fewer resources to housing rather than more. One of the reasons is that housing expenditures have to be seen in terms of the overall resource constraints on the economy and in many instances this requires a macro‐economic perspective. This paper reviews the macro‐economic arguments for and against housing expenditures, particularly through the use of a quantitative policy simulation model.