Salt intrusion in multi-channel estuaries: a case study in the Mekong Delta, Vietnam

There is a well-tested theory for the computation of salt intrusion in alluvial estuaries that is fully analytical and predictive. The theory uses analytical equations to predict the mixing behaviour of the estuary based on measurable quantities, such as channel topography, river discharge and tidal characteristics. It applies to single-channel topographies and estuaries that demonstrate moderate tidal damping. The Mekong delta is a multi-channel estuary where the tide is damped due to a relatively strong river discharge (in the order of 2000 m³/s), even during the dry season. As a result the Mekong is a strongly riverine estuary. This paper aims to test if the theory can be applied to such a riverine multi-channel estuary, and to see if possible adjustments or generalisations need to be made. The paper presents salt intrusion measurements that were done by moving boat in 2005, to which the salt intrusion model was calibrated. The theory has been expanded to cater for tidal damping. Subsequently the model has been validated with observations made at fixed locations over the years 1998 and 1999. Finally it has been tested whether the Mekong calibration fits the overall predictive equations derived in other estuaries. The test has been successful and led to a slight adjustment of the predictive equation to cater for estuaries that experience a sloping bottom

Corporate governance compliance and disclosure in the banking sector: using data from Japan

Using regression model this study investigates which characteristics of a bank is associated with the extent of corporate governance disclosure in Japan. The findings suggest that on average 8 banks out of a sample of 46 disclose optimal corporate governance information. The regression model results reveal in general that non-executive directors, cross-ownership, capital adequacy ratio and type of auditors are associated with the extent of corporate governance disclosure. Of these four variables, non-executive directors have a more significant impact on the extent of disclosure contrary to total assets and audit firms of banks in the context of Japan. The findings of this paper are relevant for corporate regulators, professional associations and developers of corporate governance code when designing or updating corporate governance code

CCS from industrial sources

The literature concerning the application of CCS to industry is reviewed. Costs are presented for different sectors including ``high purity'' (processes which inherently produce a high concentration of CO2), cement, iron and steel, refinery and biomass. The application of CCS to industry is a field which has had much less attention than its application to the electricity production sector. Costs range from less than $2011 10/tCO 2 up to above$ 2011 100/tCO 2 . In the words of a synthesis report from the United Nations Industrial Development Organisation (UNIDO) ``This area has so far not been the focus of discussions and therefore much attention needs to be paid to the application of CCS to industrial sources if the full potential of CCS is to be unlocked''

Poverty and Well-being in Post-Apartheid South Africa: An Overview of Data, Outcomes and Policy

WP 2006-03 January 2006This is an overview of poverty and well-being in the first decade of post-apartheid South Africa. It is an introduction to a volume that brings together some of the most prominent academic research done on this topic for the 10-year review process in South Africa. This overview highlights three key aspects of the picture that the detailed research paints. First, data quality and comparability has been a constant issue in arriving at a consensus among analysts on the outcomes for households and individuals in postapartheid South Africa. Second, while the outcomes on unemployment, poverty and inequality are indeed bad, the outcomes on social indicators and access to public services are much more encouraging. Third, the prospects for rapid and sustained economic growth, without which poverty and well-being cannot be addressed in the long run, are themselves negatively affected by increasing inequality, poverty and unemployment

Tracing the early development of harmful algal blooms with the aid of Lagrangian coherent structures

Several theories have been proposed to explain the development of harmful algal blooms (HABs) produced by the toxic dinoflagellate \emph{Karenia brevis} on the West Florida Shelf. However, because the early stages of HAB development are usually not detected, these theories have been so far very difficult to verify. In this paper we employ simulated \emph{Lagrangian coherent structures} (LCSs) to trace the early location of a HAB in late 2004 before it was transported to an area where it could be detected by satellite imagery, and then we make use of a population dynamics model to infer the factors that may have led to its development. The LCSs, which are computed based on a surface flow description provided by an ocean circulation model, delineate past and future histories of boundaries of passively advected fluid domains. The population dynamics model determines nitrogen in two components, nutrients and phytoplankton, which are assumed to be passively advected by the simulated surface currents. Two nearshore nutrient sources are identified for the HAB whose evolution is found to be strongly tied to the simulated LCSs. While one nutrient source can be associated with a coastal upwelling event, the other is seen to be produced by river runoff, which provides support to a theory of HAB development that considers nutrient loading into coastal waters produced by human activities as a critical element. Our results show that the use of simulated LCSs and a population dynamics model can greatly enhance our understanding of the early stages of the development of HABs.Comment: Submitted to JGR-Ocean

Reconciling local structure disorder and the relaxor state in (Bi1/2Na1/2)TiO3 -BaTiO3

Lead-based relaxor ferroelectrics are key functional materials indispensable for the production of multilayer ceramic capacitors and piezoelectric transducers. Currently there are strong efforts to develop novel environmentally benign lead-free relaxor materials. The structural origins of the relaxor state and the role of composition modifications in these lead-free materials are still not well understood. In the present contribution, the solid-solution (100-x)(Bi1/2Na1/2)TiO3-xBaTiO(3) (BNT-xBT), a prototypic lead-free relaxor is studied by the combination of solid-state nuclear magnetic resonance (NMR) spectroscopy, dielectric measurements and ab-initio density functional theory (DFT). For the first time it is shown that the peculiar composition dependence of the EFG distribution width (Delta QIS(width)) correlates strongly to the dispersion in dielectric permittivity, a fingerprint of the relaxor state. Significant disorder is found in the local structure of BNT-xBT, as indicated by the analysis of the electric field gradient (EFG) in Na-23 3QMAS NMR spectra. Aided by DFT calculations, this disorder is attributed to a continuous unimodal distribution of octahedral tilting. These results contrast strongly to the previously proposed coexistence of two octahedral tilt systems in BNT-xBT. Based on these results, we propose that considerable octahedral tilt disorder may be a general feature of these oxides and essential for their relaxor properties.ope

What can go wrong will go wrong: Birthday effects and early tracking in the German school system

At the age of ten German pupils are given a secondary school track recommendation which largely determines the actual track choice. Track choice has major effects on the life course, mainly through labor market outcomes. Using data from the German PISA extension study, we analyze the effect of month of birth and thus relative age on such recommendations. We find that younger pupils are less often recommended to and actually attend Gymnasium, the most attractive track in terms of later life outcomes. Flexible enrolment and grade retention partly offset these inequalities and the relative age effect dissipates as students age