Non-random distribution of many terrestrial so-called impact structures and its implication

Criteria used to identify crypto-explosive structures as of impact origin imply only shock. Geographical distribution of many localities is non-random and relates to distribution of carbonatites and other igneous rocks. The implications are important and numerous. One is that some “meteorites” are almost certainly Earth material, another that tektites are entirely terrestrial.     

Spatial and temporal changes in Louisiana's Barataria Basin marshes, 1945–1980

A computerized geographic information system with site-specific change-detection capabilities was developed to document amounts, rates, locations, and sequences of loss of coastal marsh to open water in Barataria Basin, Louisiana, USA. Land-water interpretations based on 1945, 1956, 1969, and 1980 aerial photographs were used as input, and a modified version of the Earth Resources Laboratory Applications Software developed by the National Aeronautics and Space Administration was used as a spatial data base management system. Analysis of these data sets indicates that rates of marsh loss have increased from 0.36% per year in the 1945–56 period, to 1.03% per year in 1956–69, and to 1.96% per year in 1969–80. The patterns of marsh loss indicate that the combination of processes causing degradation of the marsh surface does not affect all areas uniformly. Marsh loss rates have been highest where freshwater marshes have been subject to saltwater intrusion. The increase in the wetland loss rates corresponds to accelerated rates of subsidence and canal dredging and to a cumulative increase in the area of canals and spoil deposits.     

What factors control soil profile nitrogen storage?

Factors influencing soil profile nitrogen storage (SPNS) in GB have been investigated. The SPNS values of moorland peats and podzols in the South Pennines, of permanent grassland in Yorkshire, and of adjacent arable-, semi-permanent grassland- and ancient woodland-soils in Worcestershire have been compared to assess land use effects. The soils exhibited similar SPNS values, because changes in bulk density and organic matter composition offset increases in N concentrations in highly organic soils. Data from the Soil Survey of Scotland were used to show effects of soil parent material on SPNS were also small. Data on Scottish podzol soils under heather moorland and derived from sandstone or quartzite were used to show that SPNS declined with increasing precipitation, but increased with the amount of pollutant N deposited from the atmosphere.     

Integrated manufacturing,empowerment, and company performance

There is controversy over whether integrated manufacturing (IM), comprising advanced manufacturing technology, just‐in‐time inventory control and total quality management, empowers or deskills shop floor work. Moreover, both IM and empowerment are promoted on the assumption that they enhance competitiveness. We examine these issues in a study of 80 manufacturing companies. The extent of use of IM was positively associated with empowerment (i.e., job enrichment and employee skill enhancement), but, with the minor exception of AMT, bore little relationship with subsequent company performance. In contrast, the extent of empowerment within companies predicted the subsequent level of company performance controlling for prior performance, with the effect on productivity mediating that on profit. Copyright © 2004 John Wiley & Sons, Ltd.     

Controls on leaching of N species in upland moorland catchments

Spatial and temporal changes in mobility of N species have been studied for three UK upland river networks, the Etherow in the South Pennines, the Nether Beck in the Lake District and the Dee in NE Scotland. The catchments are subject to N deposition at 35.1, 22.0 and 10.8–15.6 kg N ha^?1 yr^?1, respectively. The NH⁺ ₄ leaching appears to be predominantly regulated by flow path in more polluted upland catchments. It is greatest where water draining acidified peaty soils contributes more to total discharge. Soluble organic matter may provide the dominant counter anion. In the Etherow and Dee catchments, which are dominated by acid mineral and organic soils, at high discharge NO^? ₃ also appears to be associated with greater input of water from acidified soils. In contrast, for the Nether Beck, higher NO^? ₃ concentrations are associated with tributaries draining soils contributing water with higher alkalinity, suggesting nitrification is important. For the Etherow and Dee, dissolved organic N (DON) appears to originate predominantly from acidified, peaty soils. Spiking experiments with peat soil from the Etherow catchment confirmed the limited capacity of these soils to utilize inorganic N inputs, favouring equilibration with NH⁺ ₄ inputs and leaching losses of inorganic N throughout the year.     

Landscape fires as social disasters: An overview of ‘the bushfire problem’

The ‘landscape’, ‘bushfire’ or ‘forest-fire’ problem is exemplified by the destruction of homes and human lives by landscape fires raging out of control. The ‘problem’ involves a series of landscapes (e.g. wildland and suburb), a series of systems (e.g. biophysical system and environmental-effects system), and a series of time phases (e.g. planning phase). It is a multi-stakeholder, multi-variable, multi-scale problem. Land uses, like ‘farmland’, imply a set of specific assets and, therefore, particular perceptions of losses. In all land-use designations, at any one point, fire-proneness may be seen as a function of exposure to ignition sources (embers, burning brands or flame radiation and flame contact) and the ease of ignition. The landscape-fire problem has multiple partial ‘solutions’, not just one overall solution, and these involve social governance, land management (public and private), suppression capacity and personal preparedness. The problem needs to be addressed at multiple temporal and spatial scales in an integrated fashion for the outcome to be of maximal benefit. There will always be a residual risk of severe fire occurrence. Minimisation of residual risk requires effective land management, recurrent funding and the perpetual vigilance of all parties.     

Effects of Simulated Sulphuric Acid Deposition On Calluna Vulgaris/Peat Microcosms and Associated Soil Solutions

Calluna vulgaris/peat microcosms have been used in an outdoor simulated acid rain experiment to test a series of hypotheses about sulphuric acid deposition effects upon the growth of Calluna on peat soil, namely: (1) Initially, enhanced acid input will enhance base cation and ammonium concentrations in soil solution. This may enhance uptake of these species, increasing foliar concentrations of base cations and nitrogen, and possibly foliar chlorophyll a and b concentrations. (2) If changes are induced in nutritional status, they may influence plant growth. (3) in the longer term, enhanced ammonium and base cation solubility occurring as a consequence of cation exchange reactions will lead, especially in winter months, to enhanced leaching losses. Hence any positive effects upon plant nutrition will not be sustainable. (4) the peat will acidify significantly over two years, in the shorter term primarily as a consequence of an enhanced mobile anion effect. (5) Acidification may reduce the rate of mineralisation of organic phosphorus and, in a phosphorus-deficient peat soil, this may lead to reduced foliar phosphate concentration and possibly induce phosphorus deficiency.

Most of these hypotheses were supported to some extent by the experimental results. the peat soil solution pH fell immediately in response to the acid treatments, and longer-term acidification continued progressively over the two years of the experiment. in the first year, the treatments significantly influenced the calcium, magnesium, phosphorus and nitrogen status of the leaves from Calluna new shoots, whereas in the second year calcium, potassium and phosphorus were influenced. However, in both years foliar phosphate concentration was enhanced, rather than reduced, in response to increased acid load. Foliar carbon and nitrogen concentrations fell with increasing acidity of     

Ecological differences and coexistence in a guild of microparasites: Bartonella in wild rodents

The study of ecological differences among coexisting microparasites has been largely neglected, but it addresses important and unusual issues because there is no clear distinction in such cases between conventional (resource) and apparent competition. Here patterns in the population dynamics are examined for four species of Bartonella (bacterial parasites) coexisting in two wild rodent hosts, bank voles (Clethrionomys glareolus) and wood mice (Apodemus sylvaticus). Using generalized linear modeling and mixed effects models, we examine, for these four species, seasonal patterns and dependencies on host density (both direct and delayed) and, having accounted for these, any differences in prevalence between the two hosts. Whereas previous studies had failed to uncover species differences, here all four were different. Two, B. doshiae and B. taylorii, were more prevalent in wood mice, and one, B. birtlesii, was more prevalent in bank voles. B. birtlesii, B. grahamii, and B. taylorii peaked in prevalence in the fall, whereas B. doshiae peaked in spring. For B. birtlesii in bank voles, density dependence was direct, but for B. taylorii in wood mice density dependence was delayed. B. birtlesii prevalence in wood mice was related to bank vole density. The implications of these differences for species coexistence are discussed.