111 resultados para Development and learning conceptions
Resumo:
Evidence supports local roles for TGFβ superfamily members including activins and bone morphogenetic proteins (BMP) in follicle development. Access of these ligands to signaling receptors is likely modulated by extracellular binding proteins (BP). In this study we compared expression of four BPs (chordin, gremlin, noggin, follistatin) in granulosal (GC) and theca interna (TC) compartments of developing bovine antral follicles (1-18mm). Effects of FSH and IGF on BMP and BP expression by cultured GC, and effects of LH and BMPs on BP expression by cultured TC were also examined. Follicular expression of all four BP transcripts was higher in GC than TC compartments (P<0.001) a finding confirmed by immunohistochemistry. Follicle category affected (P<0.01) gremlin and follistatin mRNA abundance, with a significant cell-type x follicle category interaction for chordin, follistatin and noggin. Noggin transcript abundance was lower (P<0.05) in GC of large 'E-active' than 'E-inactive' follicles while follistatin mRNA level was higher (P<0.01). FSH enhanced CYP19, FSHR, INHBA and follistatin by GC without affecting BMP or BMP-BP expression. IGF increased CYP19 and follistatin, reduced BMP4, noggin and gremlin but did not affect chordin or FSHR mRNA levels. LH increased TC androgen secretion but had no effect on BMP or BP expression. BMPs uniformly suppressed TC androgen production whilst increasing chordin, noggin, and gremlin mRNA levels up to 20-fold (P<0.01). These findings support the hypothesis that extracellular BP, mostly from GC, contribute to the regulation of intrafollicular BMP/activin signaling. Enhancement of thecal BP expression by BMP implies an autoregulatory feedback role to prevent excessive signaling.
Resumo:
The increasing demand for ecosystem services, in conjunction with climate change, is expected to signif- icantly alter terrestrial ecosystems. In order to evaluate the sustainability of land and water resources, there is a need for a better understanding of the relationships between crop production, land surface characteristics and the energy and water cycles. These relationships are analysed using the Joint UK Land Environment Simulator (JULES). JULES includes the full hydrological cycle and vegetation effects on the energy, water, and carbon fluxes. However, this model currently only simulates land surface processes in natural ecosystems. An adapted version of JULES for agricultural ecosystems, called JULES-SUCROS has therefore been developed. In addition to overall model improvements, JULES-SUCROS includes a dynamic crop growth structure that fully fits within and builds upon the biogeochemical modelling framework for natural vegetation. Specific agro-ecosystem features such as the development of yield-bearing organs and the phenological cycle from sowing till harvest have been included in the model. This paper describes the structure of JULES-SUCROS and evaluates the fluxes simulated with this model against FLUXNET measurements at 6 European sites. We show that JULES-SUCROS significantly improves the correlation between simulated and observed fluxes over cropland and captures well the spatial and temporal vari- ability of the growth conditions in Europe. Simulations with JULES-SUCROS highlight the importance of vegetation structure and phenology, and the impact they have on land–atmosphere interactions.
Resumo:
The growing trend of development and diversification in the British countryside stems from three main causes: the decline in farm incomes, the growing influx of non-agricultural commerce into rural areas and a change in planning policies. Even before the foot and mouth disaster, farm incomes have been in decline over the last five years, falling by as much as 90% overall in that period according to the figures issued by the Ministry of Agriculture, Fisheries and Food (MAFF). Farmers have responded to this situation in many ways, but notably through diversification. This paper examines some of the options available.
Resumo:
São Paulo is one of Latin America’s most modern and developed cities, yet around one-third of its 10 million inhabitants live in poor-quality housing in sub-standard settlements. This paper describes the response of the São Paulo municipal government that took office in 2001. Through its Secretariat of Housing and Urban Development, it designed a new policy framework with a strong emphasis on improving the quantity and quality of housing for low-income groups. Supported by new legislation, financial instruments and partnerships with the private sector, the mainstays of the new policy are integrated housing and urban development, modernization of the administrative system, and public participation in all decision-making and implementation processes. The programmes centre on upgrading and legalizing land tenure in informal settlements, and regeneration of the city centre. The new focus on valuing the investments that low-income groups have already made in their housing and settlements has proved to be more cost-effective than previous interventions, leading to improvements on an impressive scale.
Resumo:
Several brand identity frameworks have been published in the B2C and the B2B brand marketing literature. A reliable, valid and parsimonious service brand identity scale that empirically establishes the construct's dimensionality in a B2B market has yet to be developed. This paper reports the findings of a study conducted amongst 421 senior executives working in the UK IT Service sector to develop and validate a B2B Service Brand Identity Scale. Following established scale development procedures support is provided for a B2B Service Brand Identity Scale comprising five dimensions; employee and client focus, visual identity, brand personality, consistent communications and human resource initiatives. Concluding remarks discuss theoretical and managerial implications with limitations and directions for future research.