Superheavy elements: a crossroads

The failure to synthesize superheavy elements by using complete fusion reactions is most likely understandable in terms of the low survival probabilities of the superheavy precursors formed in these reactions or (in some cases) the failure to achieve complete fusion. Further attempts to synthesize these elements by using complete fusion or deep inelastic transfer reactions, or both, are discussed in light of these results.     

The carbon content of soil and its geographical distribution in Great Britain

Abstract. England and Wales have 155 314 1 × 1 km squares, of which 140049 have more than 50% soil cover. The total soil organic carbon content, based on the dominant soil series and dominant land cover type, is estimated to be 2773 × 10⁶ t C. Scotland has 84929 1 × 1 km squares, of which 82 420 have a nominated dominant soil series. The total soil organic carbon content is estimated to be 19011 × 10⁶ t C, 6.85 times the total organic carbon content of the soil of England and Wales. The total organic carbon content of the soil of Great Britain is estimated to be 21 784 × 10⁶ t C, of which 87% is in Scottish soils and 75% is in Scottish peats. A map of the mean soil organic carbon content of 10 × 10 km squares of the National Grid using classes of equal range illustrates the narrow range of organic carbon contents of the soils of England and Wales and the dominance of organic carbon in Scottish soils. A map using the same data, but with classes of unequal ranges increasing in size with increasing carbon content, is better for showing detailed differences within England and Wales.     

Salt-affected soils in England and Wales

Abstract. Soils mainly in alluvial marine sediments around the coast of England and Wales, occupy about 6% of the agricultural land. The extent of salt-affected soils within these parent materials is unknown, but is believed to be significant from the evidence of existing soil surveys.
The principal salt is sodium chloride, and the degree of salinity depends on depth to saline groundwater, the intensity of leaching, and the frequency and severity of past marine flooding. Evidence suggests that while the effects of the flooding are obvious and immediate, long-term salinity owes more to groundwater behaviour and chemistry.
The amount of sodium in these soils, particularly the heavier-textured ones, makes them structurally unstable, especially when wet. The instability in turn makes them difficult to drain. Ameliorative treatments are possible, but are expensive and slow to take effect.
In their natural or semi-natural state these soils form large areas of wetland or unimproved grassland, often of interest to conservationists. In spite of this, and their generally unfavourable properties for cultivation, extensive areas have become arable in recent years.
Structural stability, salt content, and exchangeable sodium percentage are intimately linked and can be measured during soil survey, which then aids rational decisions about land use. Such a survey of the North Kent Marshes is presented as a case study.     

Addressing foundational elements of regional land-use change forecasting

Regional land-use models must address several foundational elements, including understanding geographic setting, establishing regional land-use histories, modeling process and representing drivers of change, representing local land-use patterns, managing issues of scale and complexity, and development of scenarios. Key difficulties include managing an array of biophysical and socioeconomic processes across multiple spatial and temporal scales, and acquiring and utilizing empirical data to support the analysis of those processes. The Southeastern and Pacific Northwest regions of the United States, two heavily forested regions with significant forest industries, are examined in the context of these foundational elements. Geographic setting fundamentally affects both the primary land cover (forest) in the two regions, and the structure and form of land use (forestry). Land-use histories of the regions can be used to parameterize land-use models, validate model performance, and explore land-use scenarios. Drivers of change in the two regions are many and varied, with issues of scale and complexity posing significant challenges. Careful scenario development can be used to simplify process-based land-use models, and can improve our ability to address specific research questions. The successful modeling of land-use change in these two areas requires integration of both top-down and bottom-up drivers of change, using scenario frameworks to both guide and simplify the modeling process. Modular approaches, with utilization and integration of existing process models, allow regional land-use modelers the opportunity to better represent primary drivers of land-use change. However, availability of data to represent driving forces remains a primary obstacle.