Fine sediment delivery and transfer in lowland catchments: modelling suspended sediment concentrations in response to hydrological forcing

Fine sediment delivery to and storage in stream channel reaches can disrupt aquatic habitats, impact river hydromorphology, and transfer adsorbed nutrients and pollutants from catchment slopes to the fluvial system. This paper presents a modelling toot for simulating the time-dependent response of the fine sediment system in catchments, using an integrated approach that incorporates both land phase and in-stream processes of sediment generation, storage and transfer. The performance of the model is demonstrated by applying it to simulate in-stream suspended sediment concentrations in two lowland catchments in southern England, the Enborne and the Lambourn, which exhibit contrasting hydrological and sediment responses due to differences in substrate permeability. The sediment model performs well in the Enborne catchment, where direct runoff events are frequent and peak suspended sediment concentrations can exceed 600 mg l(-1). The general trends in the in-stream concentrations in the Lambourn catchment are also reproduced by the model, although the observed concentrations are low (rarely exceeding 50 mg l(-1)) and the background variability in the concentrations is not fully characterized by the model. Direct runoff events are rare in this highly permeable catchment, resulting in a weak coupling between the sediment delivery system and the catchment hydrology. The generic performance of the model is also assessed using a generalized sensitivity analysis based on the parameter bounds identified in the catchment applications. Results indicate that the hydrological parameters contributing to the sediment response include those controlling (1) the partitioning of runoff between surface and soil zone flows and (2) the fractional loss of direct runoff volume prior to channel delivery. The principal sediment processes controlling model behaviour in the simulations are the transport capacity of direct runoff and the in-stream generation, storage and release of the fine sediment fraction. The in-stream processes appear to be important in maintaining the suspended sediment concentrations during low flows in the River Enborne and throughout much of the year in the River Lambourn. Copyright (c) 2007 John Wiley & Sons, Ltd.

Metacognitive experience and transfer of logical reasoning

The experiments examine the influence of metacognitive experience on the transfer of logical processes in a problem solving setting. Subjects were presented with two versions of Wason's (1966) selection task. Although they were able to perform successfully on the concrete tasks (following a minimal explanation of the correct solution on an initial trial), the majority were not able to transfer a successful method to the abstract tasks. Verbalization during, or following, the concrete tasks produced substantial transfer effects however. It is suggested that verbalization may lead to an increased awareness of past behaviour, particularly of those aspects necessary for successful solution.

Code-switching and transfer: an exploration of similarities and differences

This handbook article gives an historical overview of the development of research into code-switching and discusses its relationship to other language contact phenomena.

Safeguarding inheritance and enhancing the resilience of orphaned young people living in child- and youth-headed households in Tanzania and Uganda

This paper explores the resilience of orphaned young people in safeguarding the physical assets (land and property) that they inherited from their parents and in sustaining their households without a co-resident adult relative. Drawing on the concept of resilience and the sustainable livelihoods framework, this paper analyses the findings of an exploratory study conducted with 15 orphaned young people heading households,18 of their siblings and 39 NGO workers and community members in Tanzania and Uganda. The research suggests that inherited land and property represent key determining factors in the formation and viability of child- and youth-headed households in both rural and urban areas. Despite experiences of stigma and marginalisation in the community, social networks were crucial in enabling young people to protect themselves and their property, in providing access to material and emotional resources and in enhancing their skills and capabilities to develop sustainable livelihoods. Support for child- and youth-headed households needs to recognise young people's agency and adopt a holistic approach to their lives that analyses the physical assets, material resources, human and social capital available to the household, as well as individual young people's wellbeing, outlook and aspirations. Alongside cash transfers and material support, youth-led collective mobilisation that is sustained over time may also help to build resilience and foster more supportive social environments that challenge property grabbing and the stigmatisation of child- and youth-headed households.

HIV-related stigma, asset inheritance and chronic poverty: vulnerability and resilience of widows and caregiving children and youth in Tanzania and Uganda

This paper develops a framework of risk and protective factors to conceptualise the relationship between HIV-related stigma, asset inheritance and chronic poverty among widows and caregiving children and youth in eastern Africa. Analysis of two qualitative studies with 85 participants in rural and urban areas of Tanzania and Uganda reveals that gendered and generational inequalities and stigmatisation sometimes led to property grabbing and chronic poverty. Human and social capital and preventative measures however may help widows and caregiving young people in HIV-affected households to safeguard land and other assets, within a wider supportive environment that seeks to tackle structural inequalities.

Working with legal pluralism: widowhood, property inheritance and poverty alleviation in urban Senegal

This article explores the role of women's inheritance and ownership of property in urban Senegal. It shows how being able to inherit and own property promotes the economic and emotional security of widows and their children in urban areas, and discusses the challenges posed by legal pluralism in working on poverty alleviation and social protection in the city.

Differential uptake, partitioning and transfer of Cd and Zn in the soil-pea plant-aphid system

The biomagnification of trace metals during transfer from contaminated soil to higher trophic levels may potentially result in the exposure of predatory arthropods to toxic concentrations of these elements. This study examined the transfer of Cd and Zn in a soil−plant−arthropod system grown in series of field plots that had received two annual applications of municipal biosolids with elevated levels of Cd and Zn. Results showed that biosolids amendment significantly increased the concentration of Cd in the soil and the shoots of pea plants and the concentration of Zn in the soil, pea roots, shoots, and pods. In addition, the ratio of Cd to Zn concentration showed that Zn was preferentially transferred compared to Cd through all parts of the system. As a consequence, Zn was biomagnified by the system whereas Cd was biominimized. Cd and Zn are considered to exhibit similar behaviors in biological systems. However, the Cd/Zn ratios demonstrated that in this system, Cd is much less labile in the root−shoot−pod and shoot−aphid pathways than Zn.

Inheritance, access to resources and poverty in Serer families in Senegal

This research explores the relationship between inheritance, access to resources and the intergenerational transmission of poverty among the Serer ethnic group in rural and urban environments in Senegal. In many Sub-Saharan African countries, customary law excludes women from owning and inheriting assets, such as land and property. Yet, assets controlled by women often result in increased investments in the next generation's health, nutrition and schooling and reduce the intergenerational transmission of poverty. Qualitative research with 60 participants in Senegal reveals the important role that land, housing and financial assets may play in building resilience to household shocks and interrupting the intergenerational transmission of poverty. However, the protection afforded by these assets was often dependent on other factors, including human, social and environmental capital. The death of a spouse or parent had major emotional and material impacts on many Serer families. The inheritance and control of assets and resources was strongly differentiated among family members along lines of gender, age and generation. Younger widows and their children were particularly vulnerable to chronic poverty. Although inheritance disputes were rare, the research suggests they are more likely between co-wives in polygamous unions and their children, particularly in urban areas. In addition to experiencing economic and health-related shocks, many interviewees were exposed to a range of climate-related risks and environmental pressures which increased their vulnerability. Family members coped with these shocks and risks by diversifying livelihoods, migrating to urban areas and other regions for work, participating in women's co-operatives and associations and developing supportive social networks with extended family and community members. Policies and practices that may help to alleviate poverty, safeguard women's and young people's inheritance and build resilience to financial, health-related and environmental shocks and risks include: - Social protection measures targeted towards poor widows and orphaned children, such as social and cash transfers to pay for basic needs including food, healthcare and children's schooling. - Micro-finance initiatives and credit and savings schemes, alongside training and capacity-building targeted to women and young people to develop income-generation activities and skills. - Free legal advice, support and advocacy for women and young people to pursue inheritance claims through the legal system. - Raising awareness about women's and children's legal rights and working with government and community and religious leaders to tackle discriminatory inheritance practices and contradictions caused by legal pluralism. - Increasing women's control of land and access to inputs, enhancing their business, organisational, and leadership skills and promoting civic participation in local, regional and national decision-making processes. - Improving access to basic services in rural areas, particularly healthcare, building the quality of education and promoting girls' access to education - Enhancing agricultural production and providing more employment opportunities, apprenticeships and vocational training for young people, particularly in rural areas.

Distribution and mobility of trace elements in soils and vegetation around the mining and smelting areas of Tharsis, Riotinto and Huelva, Iberian Pyrite Belt, SW Spain

Trace elements may present an environmental hazard in the vicinity of mining and smelting activities. However, the factors controlling their distribution and transfer within the soil and vegetation systems are not always well defined. Total concentrations of up to 15,195 mg center dot kg (-1) As, 6,690 mg center dot kg(-1) Cu, 24,820 mg center dot kg(-1) Pb and 9,810 mg center dot kg(-1) Zn in soils, and 62 mg center dot kg(-1) As, 1,765 mg center dot kg(-1) Cu, 280 mg center dot kg(-1) Pb and 3,460 mg center dot kg (-1) Zn in vegetation were measured. However, unusually for smelters and mines of a similar size, the elevated trace element concentrations in soils were found to be restricted to the immediate vicinity of the mines and smelters (maximum 2-3 km). Parent material, prevailing wind direction, and soil physical and chemical characteristics were found to correlate poorly with the restricted trace element distributions in soils. Hypotheses are given for this unusual distribution: (1) the contaminated soils were removed by erosion or (2) mines and smelters released large heavy particles that could not have been transported long distances. Analyses of the accumulation of trace elements in vegetation (median ratios: As 0.06, Cu 0.19, Pb 0.54 and Zn 1.07) and the percentage of total trace elements being DTPA extractable in soils (median percentages: As 0.06%, Cu 15%, Pb 7% and Zn 4%) indicated higher relative trace element mobility in soils with low total concentrations than in soils with elevated concentrations.

Factors affecting distribution and mobility of trace elements (Cu, Pb, Zn) in a perennial grapevine (Vitis vinifera L.) in the Champagne region of France

Soil and Vitis vinifera L (coarse and fine roots, leaves, berries) concentration and geochemical partitioning of Cu, Pb and Zn were determined in a contaminated calcareous Champagne plot to assess their mobility and transfer. Accumulation ratios in roots remained low (0.1-0.4 for Cu and Zn, <0.05 for Pb). Differences between elements resulted from vegetation uptake strategy and soil partitioning. Copper, significantly associated with the oxidisable fraction (27.8%), and Zn with the acid soluble fraction (33.3%), could be mobilised by rhizosphere acidification and oxidisation, unlike Pb, essentially contained in the reducible fraction (72.4%). Roots should not be considered as a whole since the more reactive fine roots showed higher accumulation ratios than coarse ones. More sensitive response of fine roots, lack of correlation between chemical extraction results and vegetation concentrations, and very limited translocation to aerial parts showed that fine root concentrations should be used when assessing bioavailability. (C) 2008 Elsevier Ltd. All rights reserved.

Public values for badgers, bovine TB reduction and management strategies

This paper applies an attribute-based stated choice experiment approach to estimate the value that society places on changes to the size of the badger population in England and Wales. The study was undertaken in the context of a rising incidence of bovine tuberculosis (bTB) in cattle and the government's review of current bTB control policy. This review includes consideration of culling badgers to reduce bTB in cattle, since badgers are thought to be an important wildlife reservoir for the disease. The design of the CE involved four attributes (size of badger population, cattle slaughtered due to bTB, badger management strategy and household tax) at four levels with eight choice sets of two alternatives presented to respondents. Telephone interviews were undertaken with over 400 respondents, which elicited their attitudes and preferences concerning badgers, bTB in cattle and badger management strategies. The study estimated a willingness to pay of 0.10 pound per household per year per 100,000 badgers and 1.52 pound per household per year per 10,000 cattle slaughtered due to bTB which aggregated to 22 per badger and 3298 pound per bTB slaughtered animal for all households in England and Wales. Management strategy toward badgers had a very high valuation, highlighting the emotive issue of badger culling for respondents and the importance of government policy towards badgers.

Identifying and understanding factors influencing the uptake of new technologies on dairy farms in SW England using the theory of reasoned action

Whilst much is known of new technology adopters, little research has addressed the role of their attitudes in adoption decisions; particularly, for technologies with evident economic potential that have not been taken up by farmers. This paper presents recent research that has used a new approach which examines the role that adopters' attitudes play in identifying the drivers of and barriers to adoption. The study was concerned with technologies for livestock farming systems in SW England, specifically oestrus detection, nitrogen supply management, and, inclusion of white clover. The adoption behaviour is analysed using the social-psychology theory of reasoned action to identify factors that affect the adoption of technologies, which are confirmed using principal components analysis. The results presented here relate to the specific adoption behaviour regarding the Milk Development Council's recommended observation times for heat detection. The factors that affect the adoption of this technology are: cost effectiveness, improved detection and conception rates as the main drivers, whilst the threat to demean the personal knowledge and skills of a farmer in 'knowing' their cows is a barrier. This research shows clearly that promotion of a technology and transfer of knowledge for a farming system need to take account of the beliefs and attitudes of potential adopters. (C) 2006 Elsevier Ltd. All rights reserved.