Mine Action Lessons and Challenges: Is Mine Action Making a Difference ... or Avoiding the Question?

Certainly, the international mine action community has learned a great deal over the past 15 years. But has mine action really made a significant difference to the people it is trying to help? Few things in mine action cause more frustration and misunderstanding among donors, recipient governments and programme managers than the question, What results has the programme achieved? Studies have decried that, despite data detailing the number of landmines destroyed, the area of land cleared and the number of people receiving mine awareness training, there are few data allowing an assessment of whether these achievements have enhanced the well-being of mine-afflicted communities

Report on the Mission to Validate the Pilot County Mine Action Plan for Croatia

This report covers the findings, conclusions, and recommendations of a mission from the Geneva International Centre for Humanitarian Mine Action (GICHD) on behalf of the UNDP-Croatia and the Croatian Mine Action Centre (CROMAC) undertaken from 11-15 November 2002. The purpose of the mission was to assess the relevance and effectiveness of the methods used to develop the pilot County Mine Action Plan (CMAC) in Croatia

Local NGOs and Firms in Mine Action

As more local nongovernmental organizations develop, establishing a distinction between local NGOs and commercial companies has become a growing concern for potential donors. The differences between NGOs and firms can be difficult to determine at times

The Road to Mine Action and Development: The Life-Cycle Perspective of Mine Action

There are four main steps to completing the life cycle of mine action, and demining is just a small part. Without development, citizens continue to live in poverty and under oppression. The authors outline the four-step life cycle of mine action

A New Mechanism for Generation of Langmuir Circulations

A new mechanism has been identified that explains the generation of Langmuir circulations. A wind-driven current in the presence of surface waves gives rise to an instability where the emerging circulations redistribute the turbulence in the cross-wind direction. The non-uniform eddy-viscosity locally changes the rate of momentum transfer from the wind to the shear current, producing a non-uniform velocity field. The interaction of this non-uniform velocity field with the surface waves, due to the Craik-Leibovich vortex force, amplifies the circulations and creates a feedback mechanism. The currently accepted CL2 model of instability assumes a constant eddy-viscosity. This paper presents a model which explains the generation of Langmuir circulations and its predictions of both spatial and time scales are in good agreement with experimental results. The modeling approach combines a perturbation method with a RANS turbulence model. Through parametric variation of the perturbation, the growth rate and spatial scales of the circulations are extracted from the simulations

Effects of soil type and composition of rhizodeposits on rhizosphere priming phenomena

Inputs of fresh plant-derived C may stimulate microbially-mediated turnover of soil organic matter (SOM) in the rhizosphere. But studies of such ‘priming’ effects in artificial systems often produce conflicting results, depending on such variables as rates of substrate addition, substrate composition, whether pure compounds or mixtures of substrates are used, and whether the addition is pulsed or continuous. Studies in planted systems are less common, but also produce apparently conflicting results, and the mechanisms of these effects are poorly understood. To add to the evidence on these matters, we grew a C4 grass for 61 d in two contrasting soils – an acid sandy soil and a more fertile clay-loam – which had previously only supported C3 vegetation. We measured total soil respiration and its C isotope composition, and used the latter to partition the respiration between plant- and soil-C sources. We found SOM turnover was enhanced (i.e. positive priming) by plant growth in both soils. In treatments in which the grass was clipped, net growth was greatly diminished, and priming effects were correspondingly weak. In treatments without clipping, net plant growth, total soil respiration and SOM-derived respiration were all much greater. Further, SOM-derived respiration increased over time in parallel with increases in plant growth, but the increase was delayed in the less fertile soil. We conclude the observed priming effects were driven by microbial demand for N, fuelled by deposition of C substrate from roots and competition with roots for N. The extent of priming depended on soil type and plant growing conditions. In a further experiment, we simulated rhizodeposition of soluble microbial substrates in the same two soils with near-continuous additions for 19 d of either C4-labelled sucrose (i.e. a simple single substrate) or a maize root extract (i.e. a relatively diverse substrate), and we measured soil respiration and its C isotope signature. In the more fertile soil, sucrose induced increasingly positive priming effects over time, whereas the maize root extract produced declining priming effects over time. We suggest this was because N and other nutrients were provided from the mineralization of this more diverse substrate. In the less-fertile soil, microbial N demand was probably never satisfied by the combined mineralization from added substrate and soil organic matter. Therefore priming effects were approximately constant over time. We conclude that the chemical nature of putative priming compounds can greatly influence priming phenomena

Fine scale measurement and mapping of uranium in soil solution in soil and plant-soil microcosms, with special reference to depleted uranium

Background and aims: Residues from use of depleted uranium (DU) munitions pose a lasting environmental impact through persistent contamination of soils. Consequently, an understanding of the factors determining the fate of DU in soil is necessary. An understudied factor is the interaction of root exudates with DU. This study describes the use of ‘Single-Cell-Sampling-and-Analysis' (SiCSA) for the first time in soil and investigates the effects of root exudates on DU dissolution. Methods: Soil solutions from soil and plant-soil microcosms containing DU fragments were sampled and analysed using SiCSA and capillary electrophoresis/ICP-MS for organic acids and uranium. Results: Nanolitre volumes of soil solution were sampled and analysed. Soils with DU fragments but no citrate addition showed low uranium concentrations in contrast to those with added citrate. Lupin root exudation gave concentrations up to 8mM citrate and 4.4mM malate in soil solution which solubilised DU fragments yielding transient solution concentrations of up to 30mM. Conclusions: Root exudates solubilise DU giving high localised soil solution concentrations. This should be considered when assessing the environmental risk of DU munitions. The SiCSA method was used successfully in soil for the first time and enables investigations with high spatial and temporal resolution in the rhizosphere. Figur