Do metal concentrations in moss from the Zackenberg area,Northeast Greenland,provide a baseline for monitoring?

Purpose  

This study aims at evaluating (a) whether concentrations of a suite of elements in mosses sampled in the arctic region around Zackenberg reflect background concentrations useful for estimating pollution levels in industrialized parts of the northern hemisphere as is attempted, e.g. in the framework of the UNECE ICP Vegetation monitoring programme, and (b) whether there are any influences from Zackenberg research station detectable in these concentrations.     

Migration of Cs in tributaries,lake water and sediment of Lago Maggiore (Italy,Switzerland) – analysis and comparison with Lago di Lugano and other lakes

This paper describes the behaviour of ¹³⁷Cs in Lago Maggiore and other pre-alpine lakes as a consequence of atmospheric nuclear weapons testing fallout and the fallout from the nuclear accident in Chernobyl. It presents data on the ¹³⁷Cs distribution in tributaries, lake water, bottom sediments and reveals the role of ¹³⁷Cs as a marker of the sedimentation processes. The run-off of ¹³⁷Cs from the watershed to the lake is described with a simple compartment model. Measurements of the activity concentration of ¹³⁷Cs in sediments are compared with the output of a model (diffusion–convection type) which describes the input of ¹³⁷Cs into and its vertical distribution within the sediment. Varying sedimentation rates (0.05–0.90 g (cm² y)⁻¹) in Lago Maggiore are compared with data of other authors. Sedimentation rates and total distribution coefficients (of about 10⁵ L kg⁻¹) in Lago Maggiore are discussed and compared with those of Lago di Lugano, Lake Constance, and Lake Vorsee.     

Dynamics and sustainability of urban agriculture: examples from sub-Saharan Africa

Urban agriculture can have many different expressions, varying from backyard gardening to poultry and livestock farming. This article focuses on crop production on larger open spaces in cities of sub-Saharan Africa (SSA) and investigates the sustainability and dynamics of this type of land use, which is common on undeveloped plots particularly in lowlands, such as in inland valleys, or along urban streams or drains. An adapted version of the Framework for Evaluating Sustainable Land Management (FESLM) developed by the Food and Agriculture Organization of the United Nations (FAO) was used to assess the sustainability of urban agriculture. As an example for dynamics, the spatio-temporal changes of open-space agriculture in Dar es Salaam, Tanzania, are analyzed for the period from 1992 to 2005, and compared with data from other cities. Crop production on urban open spaces appears as a market-driven, highly productive and profitable phenomenon. However, it is often constrained by tenure insecurity and non-agricultural land demands. Also, the common use of polluted water limits the official support of irrigated urban farming. However, despite these constraints, the phenomenon of urban farming appears persistent and resilient to its changing environment, although individual farmers might have to shift to other sites when their plots are needed for construction. Open-space vegetable production in urban areas is a dynamic, viable and largely sustainable livelihood strategy, especially for poor urban dwellers. Spatio-temporal analysis shows that it is not a short-lived or transitional phenomenon—probably as long as it can maintain its comparative market advantage. However, its informal nature and resulting lack of political recognition need to be addressed.     

Speciation and toxicological relevance of manganese in humans

Although manganese is an essential trace element, concerns are rising about the Mn exposure of humans being related to neurotoxic effects. This review summarizes several aspects of this topic to provide updated information on Mn related investigations, including chemical speciation of Mn-compounds. The paper starts with some chemical aspects of Mn and its compounds, enlightening oxidation states in general and in biological matrices. This is followed by considerations on natural sources of human exposure, on occupational sources and on anthropogenically caused environmental sources, for example from the use of methylcyclopentadienyl manganese tricarbonyl (MMT). Next, the paper deals with Mn levels in the human organism, showing normal Mn concentrations in various tissues or body fluids, and continues with the toxicology of Mn, i.e. absorption, distribution and excretion. Of specific concern is the transfer of Mn to the brain which is the relevant neurotoxic target. In this context, parallels and differences between primary and Mn-dependent Parkinsonism are discussed, concluding with a risk assessment and a consideration of susceptible groups. The main part of this review focuses on recent investigations on Mn speciation. Analytical problems and their solutions are also described for correct identification of relevant Mn-compounds in matrices of human origin. Finally, future needs are discussed, such as further investigations on those Mn-species which may overcome neural barrier control, on disease-modulated barrier control, on susceptibility to certain Mn-species, and on the interaction of Mn with Fe-homeostasis in the brain.     

The central role of centralisation in environmental policy initialisation

While economic research on environmental policy is mainly concerned with instruments, political science concentrates on actors. The issue of centralisation needs to be analysed using a multidisciplinary approach because it is connected with both actors and instruments. Linking the Advocacy Coalition Framework with an economic approach, the paper first develops an innovative model in order to understand the mechanisms of centralisation and decentralisation in the different phases of policy processes. Focusing on environmental policy, the idea is developed that environmental policy needs the push of centralisation in order to institutionalise the prevailing social norm, but then should be organised decentrally to account for regional differences. The examples of air pollution, climate change and urban sprawl are used to test the explanatory power of the theoretical approach.     

Biomechanical Consequences of the Hand’s Action on Unstable Handle

The concept of muscular stabilization refers to imposing active muscular constraints on the joint degrees of freedom that are not used in a given motor task and the stabilization of unstable working objects. The human organism bears considerable cost due to the realization of this process, which in the case of muscular static force developed in relation to an unstable working object reaches approximately 24%. The aim of this article is twofold: (a) to determine the useful efficiency of the hand-working object system with an unstable handle in relation to the released muscular force and power dynamics and (b) to identify the relative contribution of the upper extremity muscles engaged in the realization of motor or stabilizing functions in the electromyography (EMG) sphere.     

The distribution of lianas and their change in abundance in temperate forests over the past 45 years

Lianas (woody vines) are an important and dynamic component of many forests throughout the world, and increases in CO2, mean winter temperature, and forest fragmentation may promote their growth and proliferation in temperate forests. In this study, we used a 45-year data set to test the hypothesis that lianas have increased in abundance and basal area in the interiors of 14 deciduous temperate forests in Wisconsin (USA) since 1959. We also censused woody plants along a gradient from the forest edge to the interior in seven of these forests to test the hypothesis that the abundance of lianas declines significantly with increasing distance from the forest edge. We found that lianas did not increase in abundance within the interiors of temperate forests in Wisconsin over the last 45 years. However, relative and absolute liana abundance decreased sharply with increasing distance from forest edges. Our findings suggest that forest fragmentation, not climate change, may be increasing the abundance of lianas in northern deciduous temperate forests, and that lianas may further increase in abundance if the severity of forest fragmentation intensifies.     

Diurnal variations of abiotic parameters in a stream,recipient for drainage water in Ranstad,southwest Sweden

During 24 h, water samples were taken for determination of a number of key parameters in a water system containing high concentrations of FeII at circumneutral pH. None of the major constituents (Ca, Mg, Na, K and sulfate) showed diurnal variations, while dissolved oxygen and pH increased during the night. This increase could entirely be explained by the decrease in water temperature. However, the concentration of FeII slightly increased at constant concentration of total Fe during the night, opposite to earlier observations in other systems where the presence of FeII was shown to be controlled by photoreduction. Nocturnal peaks of FeII have also been observed in other systems with high iron concentrations, however, at acidic pH, but without obvious explanation. The mechanisms for this process therefore need further investigation.     

Design trade-offs in rights-based management of small-scale fisheries

Small-scale fisheries collectively have a large ecological footprint and are key sources of food security, especially in developing countries. Many of the data-intensive approaches to fishery management are infeasible in these fisheries, but a strategy that has emerged to overcome these challenges is the establishment of territorial user rights for fisheries (TURFs). In this approach, exclusive fishing zones are established for groups of stakeholders, which eliminates the race to fish with other groups. A key challenge, however, is setting the size of TURFs—too large and the number of stakeholders sharing them impedes collective action, and too small and the movement of target fish species in and out of the TURFs effectively removes the community's exclusive access. We assessed the size of 137 TURFs from across the globe relative to this design challenge by applying theoretical models that predict their performance. We estimated that roughly two-thirds of these TURFs were sized ideally to overcome the challenges posed by resource movement and fisher group size. However, for most of the remaining TURFs, all possible sizes were either too small to overcome the resource-movement challenge or too large to overcome the collective action challenge. Our results suggest these fisheries, which target mobile species in densely populated regions, may need additional interventions to be successful.