A review of the potential impacts of climate change on surface water quality

It is now accepted that some human-induced climate change is unavoidable. Potential impacts on water supply have received much attention, but relatively little is known about the concomitant changes in water quality. Projected changes in air temperature and rainfall could affect river flows and, hence, the mobility and dilution of contaminants. Increased water temperatures will affect chemical reaction kinetics and, combined with deteriorations in quality, freshwater ecological status. With increased flows there will be changes in stream power and, hence, sediment loads with the potential to alter the morphology of rivers and the transfer of sediments to lakes, thereby impacting freshwater habitats in both lake and stream systems. This paper reviews such impacts through the lens of UK surface water quality. Widely accepted climate change scenarios suggest more frequent droughts in summer, as well as flash-flooding, leading to uncontrolled discharges from urban areas to receiving water courses and estuaries. Invasion by alien species is highly likely, as is migration of species within the UK adapting to changing temperatures and flow regimes. Lower flows, reduced velocities and, hence, higher water residence times in rivers and lakes will enhance the potential for toxic algal blooms and reduce dissolved oxygen levels. Upland streams could experience increased dissolved organic carbon and colour levels, requiring action at water treatment plants to prevent toxic by-products entering public water supplies. Storms that terminate drought periods will flush nutrients from urban and rural areas or generate acid pulses in acidified upland catchments. Policy responses to climate change, such as the growth of bio-fuels or emission controls, will further impact freshwater quality.

Influence of dissolved organic matter on the solubility of heavy metals in sewage-sludge-amended soils

Sewage-sludge-amended soils generally contain elevated levels of organic matter and heavy metals compared to control soils. Because organic matter is known to complex with heavy metals, the solubility behavior of the organic matter in such soils may exert a significant influence on the solubility of the metals. Little is known about such a process. Using batch experiments in which the solubility of organic matter in a heavily sludge-amended soil was artificially manipulated, we show that the solubilities of the heavy metals copper (Cu), nickel (Ni), and lead (Pb) show a strong positive relationship to the solubility of organic matter, particularly at high pH. The results suggest that under field conditions, spatiotemporal variations in the solid-solution partitioning of organic matter may have a bearing on the environmental significance (mobility and bioavailability) of these heavy metals.

Geochemical changes to dredged canal sediments following land spreading: a review.

This paper brings together some of the recent research on trace metals in dredged sediments, and in particular freshwater canal sediments. Following a description of the general UK background, geochemical processes that affect metal release and retention in dredged canal sediments are considered, particularly the role of redox and sulphur on metal associations, and the use of sequential extraction for the derivation of metal associations in sediments. The review outlines the importance of oxidation on metal-mobility and shows that many studies have illustrated the increase in metal-leachability from sediments during oxidation. Suggestions are given for sediment-testing requirements which should include an examination of both anoxic and oxidised sediment as well as ecotoxicology in order to account for changes to metal-speciation after disposal to land.

Transnationalism personified: young returning Trinidadians 'in their own words'

In this paper we consider the nexus existing between returning transnational migrants to Trinidad and Tobago's adaptation experiences, matters pertaining to their transnational life-paths, family and community experiences and their views on transnationalism and return. The research is based on an analysis of the detailed narratives provided by forty informants by means of semi-structured interviews. The informants consisted of nine 'second-generation', seven 'one-and-a-half-generation' and twenty-four 'prolonged sojourner' returning transnational migrants to Trinidad and Tobago. The main conceptual themes that characterise Caribbean transnationalism are presented at the beginning of the paper. Addressing these in the context of Trinidad and Tobago, we present our narrative-based findings under the following headings derived from analysis of our informant's experiences and views: transnational family and life-course issues; transnational community relationships; keeping in touch; transnational mobility and 'home as fixed anchor'; transnational identity; transnational economic and commercial interests; and strategic flexibility.

Supporting ad hoc collaborations in peer-to-peer networks

Traditionally, applications and tools supporting collaborative computing have been designed only with personal computers in mind and support a limited range of computing and network platforms. These applications are therefore not well equipped to deal with network heterogeneity and, in particular, do not cope well with dynamic network topologies. Progress in this area must be made if we are to fulfil the needs of users and support the diversity, mobility, and portability that are likely to characterise group work in future. This paper describes a groupware platform called Coco that is designed to support collaboration in a heterogeneous network environment. The work demonstrates that progress in the p development of a generic supporting groupware is achievable, even in the context of heterogeneous and dynamic networks. The work demonstrates the progress made in the development of an underlying communications infrastructure, building on peer-to-peer concept and topologies to improve scalability and robustness.

Incorporation of lead into calcium carbonate granules secreted by earthworms living in lead contaminated soils

The influence of soil organisms on metal mobility and bioavailability in soils is not currently fully understood. We conducted experiments to determine whether calcium carbonate granules secreted by the earthworm Lumbricus terrestris could incorporate and immobilise lead in lead- and calcium- amended artificial soils. Soil lead concentrations were up to 2000 mg kg-1 and lead:calcium ratios by mass were 0.5-8. Average granule production rates of 0.39 + 0.04 mgcalcite earthworm-1 day-1 did not vary with soil lead concentration. The lead:calcium ratio in granules increased significantly with that of the soil (r2 = 0.81, p = 0.015) with lead concentrations in granules reaching 1577 mg kg-1. X-ray diffraction detected calcite and aragonite in the granules with indications that lead was incorporated into the calcite at the surface of the granules. In addition to the presence of calcite and aragonite X-ray absorption spectroscopy indicated that lead was present in the granules mainly as complexes sorbed to the surface but with traces of lead-bearing calcite and cerussite. The impact that lead-incorporation into earthworm calcite granules has on lead mobility at lead-contaminated sites will depend on the fraction of total soil lead that would be otherwise mobile.

Head-controlled assistive telerobot with extended physiological proprioception capability

People with disabilities such as quadriplegia can use mouth-sticks and head-sticks as extension devices to perform desired manipulations. These extensions provide extended proprioception which allows users to directly feel forces and other perceptual cues such as texture present at the tip of the mouth-stick. Such devices are effective for two principle reasons: because of their close contact with the user's tactile and proprioceptive sensing abilities; and because they tend to be lightweight and very stiff, and can thus convey tactile and kinesthetic information with high-bandwidth. Unfortunately, traditional mouth-sticks and head-sticks are limited in workspace and in the mechanical power that can be transferred because of user mobility and strength limitations. We describe an alternative implementation of the head-stick device using the idea of a virtual head-stick: a head-controlled bilateral force-reflecting telerobot. In this system the end-effector of the slave robot moves as if it were at the tip of an imaginary extension of the user's head. The design goal is for the system is to have the same intuitive operation and extended proprioception as a regular mouth-stick effector but with augmentation of workspace volume and mechanical power. The input is through a specially modified six DOF master robot (a PerForceTM hand-controller) whose joints can be back-driven to apply forces at the user's head. The manipulation tasks in the environment are performed by a six degree-of-freedom slave robot (the Zebra-ZEROTM) with a built-in force sensor. We describe the prototype hardware/software implementation of the system, control system design, safety/disability issues, and initial evaluation tasks.

Impact of earthworms on trace element solubility in contaminated mine soils amended with green waste compost

The common practice of remediating metal contaminated mine soils with compost can reduce metal mobility and promote revegetation, but the effect of introduced or colonising earthworms on metal solubility is largely unknown. We amended soils from an As/Cu (1150 mgAs kg−1 and 362 mgCu kg−1) and Pb/Zn mine (4550 mgPb kg−1 and 908 mgZn kg−1) with 0, 5, 10, 15 and 20% compost and then introduced Lumbricus terrestris. Porewater was sampled and soil extracted with water to determine trace element solubility, pH and soluble organic carbon. Compost reduced Cu, Pb and Zn, but increased As solubility. Earthworms decreased water soluble Cu and As but increased Pb and Zn in porewater. The effect of the earthworms decreased with increasing compost amendment. The impact of the compost and the earthworms on metal solubility is explained by their effect on pH and soluble organic carbon and the environmental chemistry of each element.

Modelling of the natural chlorine cycling in a coniferous stand: implications for chlorine-36 behaviour in a contaminated forest environment

Considered as one of the most available radionuclide in soileplant system, 36Cl is of potential concern for long-term management of radioactive wastes, due to its high mobility and its long half-life. To evaluate the risk of dispersion and accumulation of 36Cl in the biosphere as a consequence of a potential contamination, there is a need for an appropriate understanding of the chlorine cycling dynamics in the ecosystems. To date, a small number of studies have investigated the chlorine transfer in the ecosystem including the transformation of chloride to organic chlorine but, to our knowledge, none have modelled this cycle. In this study, a model involving inorganic as well as organic pools in soils has been developed and parameterised to describe the biogeochemical fate of chlorine in a pine forest. The model has been evaluated for stable chlorine by performing a range of sensitivity analyses and by comparing the simulated to the observed values. Finally a range of contamination scenarios, which differ in terms of external supply, exposure time and source, has been simulated to estimate the possible accumulation of 36Cl within the different compartments of the coniferous stand. The sensitivity study supports the relevancy of the model and its compartments, and has highlighted the chlorine transfers affecting the most the residence time of chlorine in the stand. Compared to observations, the model simulates realistic values for the chlorine content within the different forest compartments. For both atmospheric and underground contamination scenarios most of the chlorine can be found in its organic form in the soil. However, in case of an underground source, about two times less chlorine accumulates in the system and proportionally more chlorine leaves the system through drainage than through volatilisation.

Moving on in Neolithic studies: understanding mobile lives

Mobility is a fundamental facet of being human and should be central to archaeology. Yet mobility itself and the role it plays in the production of social life, is rarely considered as a subject in its own right. This is particularly so with discussions of the Neolithic people where mobility is often framed as being somewhere between a sedentary existence and nomadic movements. This volume examines the importance and complexities of movement and mobility, whether on land or water, in the Neolithic period. It uses movement in its widest sense, ranging from everyday mobilities – the routines and rhythms of daily life – to proscribed mobility, such as movement in and around monuments, and occasional and large-scale movements and migrations around the continent and across seas. Papers are roughly grouped and focus on ‘mobility and the landscape’, ‘monuments and mobility’, ‘travelling by water’, and ‘materials and mobility’. Through these themes the volume considers the movement of people, ideas, animals, objects, and information, and uses a wide range of archaeological evidence from isotope analysis; artefact studies; lithic scatters and assemblage diversity.

Movements of neotropical understory passerines affected by anthropogenic forest edges in the Brazilian Atlantic rainforest

Edge effects are suggested to have great impact on the persistence of species in fragmented landscapes. We tested edge avoidance by forest understory passerines in the Brazilian Atlantic Rainforest and also compared their mobility and movement patterns in contiguous and fragmented landscapes to assess whether movements would increase in the fragmented landscape. Between 2003 and 2005, 96 Chiroxiphia caudata, 38 Pyriglena leucoptera and 27 Sclerurus scansor were radio-tracked. The most strictly forest species C. caudata and S scansor avoided forest edges while P leucoptera showed affinities for the edge Both sensitive species showed larger mean step length and maximal observed daily distance in the fragmented forest versus the unfragmented forest. P. leucoptera did not show any significant difference. There were no significant differences in proportional daily home range use for any of the three species. Our results suggested that fragmentation and the consequent increase in edge areas do influence movement behavior of sensitive forest understory birds that avoided the use of edges and increased the speed and distance they covered daily. For the most restricted forest species, it would be advisable to protect larger patches of forest instead of many small or medium fragments connected by narrow corridors. However, by comparing our data with that obtained earlier, we concluded that movement behavior of resident birds differs from that of dispersing birds and might not allow to infer functional connectivity or landscape-scale sensitivity to fragmentation; a fact that should be taken into consideration when suggesting conservation strategies. (c) 2008 Elsevier Ltd. All rights reserved.

The most severe parkinsonian patients are most improved with duodenal levodopa infusion

Objectives:To find variables correlated to improvement with intraduodenal levodopa/carbidopa infusion (Duodopa) in order to identify potential candidates for this treatment. Two clinical studies comparing Duodopa with oral treatments in patients with advanced Parkinson’s disease have shown significant improvement in percent on-time on a global treatment response scale (TRS) based on hourly and half-hourly clinical ratings and in median UPDRS scores.Methods:Data from study 1 comparing infusion with Sinemet CR (12 patients, Nyholm et al, Clin Neuropharmacol 2003; 26(3): 156-163) and study 2 comparing infusion with individually optimised conventional combination therapies (18 patients, Nyholm et al, Neurology, in press) were used. Measures of severity were defined as total UPDRS score and scores for sections II and III, percent functional on-time and mean squared error of ratings on the TRS and as mean of diary questions about mobility and satisfaction (only study 2). Absolute improvement was defined as difference in severity, and relative improvement was defined as percent absolute improvement/severity on oral treatment. Pearson correlation coefficients between measures of improvement and other variables were calculated.Results:Correlations (r2>0.28, p<0.05) between severity during oral treatment and absolute improvement on infusion were found for: Total UPDRS, UPDRS III and TRS ratings (studies 1 and 2) and for diary question 1 (mobility) and UPDRS II (study 2). Correlation to relative improvement was found for total UPDRS (study 2, r2=0.47). Figure 1 illustrates absolute improvement in total UPDRS vs. total UPDRS during oral treatment (study 2).Conclusion:Correlating different measures of severity and improvement revealed that patients with more severe symptoms were most improved and that the relation between severity and improvement was linear within the studied groups. The result, which was reproducible between two clinical studies, could be useful when deciding candidates for the treatment.

O Conselho Municipal de Desenvolvimento Sustentável (CMDS) e a gestão de recursos hídricos: um estudo na Bacia do Rio Itabapoana (RJ)

O objetivo desta dissertação é analisar a forma de atuação do CMDS, e sua contribuição para a gestão dos recursos hídricos nos cinco municípios do Rio de Janeiro pertencentes à bacia do rio Itabapoana. O presente estudo foi conduzido a partir de uma discussão teórica sobre os temas: desenvolvimento local, cidadania, desenvolvimento local com cidadania e gestão social. Posteriormente, foram realizadas entrevistas temáticas, baseadas no método não probabilístico, com uma amostra composta por 38 pessoas, entre conselheiros do CMDS (membros do poder público e sociedade civil organizada), técnico, consultores e gestores do Sebrae/RJ. No tratamento dos dados foi utilizada a análise de discurso. Foram identificados aspectos negativos e positivos no que diz respeito à atuação e funcionamento do Conselho nos municípios analisados. Mesmo assim, pode-se verificar que grande parte dos conselheiros tem experiência anterior em Conselhos e movimentos sociais, e que o Projeto Managé, por meio da atuação dos CMDS, ajudou a construir uma identidade territorial para a bacia e também despertou a necessidade de maior conscientização e preservação do meio ambiente. Pode-se concluir que a forma de atuação do CMDS depende da interação e do nível de comprometimento do poder público e da sociedade civil organizada. Portanto, as condições institucionais locais exercem importante influência nas formas de mobilização social e participação dos indivíduos, visto que o processo de gerenciamento de recursos hídricos da bacia encontra-se ainda em fase de construção

Preconceito e estereótipos relativos a cor, sexo e status

Esta pesquisa investiga os estereótipos positivos e/ou negativos, quando considerados como variáveis de cor, sexo status. O instrumento utilizado consistiu de oito desenhos estímulos, sendo quatro homens e quatro mulheres: homem branco de status alto (HBR), homem negro de status alto (HNR), homem branco de status baixo (HBP), homem negro de status baixo (HNP), mulher branca de status alto (MBR), mulher negra de status alto (MNR), mulher branca de status baixo (MBP) e mulher negra de status baixo (MNP), distribuídos equitativamente pela amostra, em um questionário com nove itens objetivos para pedir sobre o desenho estímulo, a distância social, a escolaridade, a posição hierárquica no trabalho, a ocupação desempenhada pelo estímulo e por seus pais para averiguar a mobilidade social, a classe sócio econômica e um item em aberto para apreender como a amostra percebe os estímulos. A amostra foi composta de 930 sujeitos: 482 de cor epidérmica e atributos físicos (boca, cabelos e sujeitos nariz) brancos e 448 sujeitos negros de cor epidérmica e atributos físicos negros, ou cor epidérmica branca e atributos físicos negros, ou cor epidérmica negra e atributos físicos brancos, atribuídos pelo experimentador. Estes mesmos sujeitos se auto classificaram como sendo 602 sujeitos "brancos" e 328 sujeitos negros. A hipótese básica testada foi: "Há estereótipos positivos e negativos relativos à cor, sexo e status." O único item que rejeitou a hip6tese nula básica, foi aquele sobre a ocupação desempenhada pelas figuras-estímulos onde as amostras brancas, atribuída pelo experimentador e autoclasificada, e negra autoclassificada corno branca, rejeitaram-na quanto às variáveis de sexo e status, sugerindo que os estereótipos aparecem de acordo com as ocupações atribuídas, quanto ao sexo e status das figuras-estímulos. As amostras negras, atribuída pelo experimentador e autoclassificada, rejeitaram-nas três variáveis, mostrando a influência da cor, sexo e status, separadamente, sobre o estereótipo medido através da ocupação atribuída aos estímulos, além da interação cor X status, sugerindo também a presença do estereótipo ocupacional, quando a cor se associa ao status dos desenhos. A amostra negra, atribuída pelo experimentador, rejeita-a, ainda, na interação cor X sexo X status parecendo existir discriminação quanto as ocupações dadas aos estímulas, quando estas três variáveis se associam. As amostras brancas, atribuída pelo experimentador e autoclassificada, apresentaram respostas ambíguas na maioria dos itens. As amostras negras, atribuída pelo experimentador e autoclassificada, não mostraram diferenças significativas entre as respostas, em parte dos itens. O critério ABIPEME expressou que ambas as amostras branca e negra, atribuídas pelo experimentador, apresentaram alta escolaridade e bom nível sócio-econômico. O número de mulheres era superior ao número de homens, embora homens e mulheres se equivalessem em ambas as amostras, o que sugere que mulheres brancas e negras e homens negros se com portaram de acordo com os valores culturais e dominantes, demonstrando auto-desvalorização e baixa auto-estima.