Sedimentology has seen many significant advances and changes over the past 40 years, ranging from facies modelling to sequence stratigraphy; chemostratigraphy to basin analysis; and the integration of studies of physical, chemical and, increasingly, biological processes in the interpretation and prediction of sedimentary environments and products. The subject is becoming ever more interdisciplinary and applied, and now has far more links to other physical sciences. Research and debate are continuing afresh as we move into this new interdisciplinary phase and promise many developments and increased uses of our subject. Now seemed a good time to publish a series of review papers concerning some key current areas of research. We hope that these papers will provide comprehensive starting points for those wishing to become acquainted with an area, act as stimuli for debate, and provide awareness and ideas for future research avenues. No issue of this sort can, of course, ever be truly comprehensive in its coverage: these reviews concern only selected snippets from the wide scope of sedimentology and each has, of necessity, been selective in its own area.

The 'National Policy on PPP' recently approved by the Government of Ghana (GoG) sets out the government's intention to use Public-Private Partnerships (PPPs) to 'improve the quality, cost-effectiveness, and timely provision of public infrastructure in Ghana.' The PPP Policy highlights the role of the government's financial support to PPPs, as well as the importance of putting in place a system to manage the associated fiscal commitments (FCs). This study proposes an operational framework for managing fiscal obligations arising from PPPs in Ghana. This framework aims to ensure that PPP FCs are consistently identified and assessed during PPP project preparation, and that these assessments are fed into project approval. The framework will also ensure that PPP FCs are monitored, reported on, and budgeted for appropriately over the lifetime of PPP projects. To that end, the report outlines roles and responsibilities, concepts, and processes for managing PPP FCs, drawing on international standards and practices, bearing in mind existing institutions and capacities in Ghana. The report also suggests legislative additions and capacity-building needed to establish this framework in practice.

Nigeria's Vision 2020 has expressed a bold desire for the country to be among the world's top 20 economies by the year 2020. The economy has posted impressive growth figures since 2003, driven by higher oil revenues and a series of home-grown economic reforms. The country is now firmly on the road to middle-income status. But what else do government and the private sector need to do to create the jobs and growth that will underpin the national development strategy? What are the challenges that Nigeria's businesses face today? 'An Assessment of the Investment Climate in Nigeria' provides answers to these questions. Based on a survey of 2,300 companies, it provides evidence-based recommendations designed to support Vision 2020 and the president's seven-point agenda. The authors find that government must move quickly to create jobs and reduce poverty. Key challenges include a desperate shortage of energy and a poor transportation network, as well as low levels of education and continuing unrest in the Niger delta. In addition, Nigeria's workers need to become more productive in order to compete in a globalized economy. As a matter of fact, they are less productive than workers in more dynamic countries, such as Brazil, China, and Kenya. Improving productivity will require simultaneous efforts to foster competition, improve specific aspects of the business environment, and facilitate better management and training within individual firms. In addition to the issues of productivity, Nigeria's best firms have not been able to expand their market share. Consequently, policy makers need to address and elimate obstacles to competition, including barriers to entry, convoluted taxation, property registration, and licensing.