Geographies of children, youth and families: an international perspective

This edited collection brings together international experts from the vibrant and growing field of geographies of children, youth and families. The book provides an overview of current conceptual and theoretical debates, and gives a wide range of examples of cutting-edge research from a variety of national contexts across the globe. The theme of 'disentangling the socio-spatial contexts of young people and/or their families' advances debates in geographies and social studies of young people and families by emphasising the context of young people's social agency. The book is designed to provide an introduction to the topic of geographies of children, youth and families and is an invaluable course text for undergraduate and postgraduate students of geography and the social sciences. This interdisciplinary text is also of likely interest to students and practitioners of education, youth work, social policy and social work.

Youth/youth cultures

Youth is an embodied social construct attached to people who are too young to be classified as fully adult, and yet older than children. It is a term whose meaning is sociospatially specific and shifting. Youth and young people are often perceived as troubling to society, and the earliest studies of youth were tied to attempts to control unruly young people. Studies of youth cultures often utilized ethnographic research to explore the perspectives of young people. Early youth cultural studies inadvertently reproduced some dominant representations of youth, as male and troubling to society, by focusing upon subcultural groupings, such as Punks and Mods, and by excluding accounts of those other than white, heterosexual males. Recent studies have moved beyond these accounts to consider how youth cultures are porous, differentiated rather than holistic, connected to broader sociospatial processes, and can reproduce powerful social relationships, such as gender, along with teasing out how youth cultures are played out differently in various geographical contexts.

Poverty, migration and sex work: youth transitions in Ethiopia

Despite an emerging body of work on youth transitions, research has yet to explore the often unconventional routes to adulthood for young people marginalised through poverty. By drawing on interviews with 60 young commercial sex workers in Ethiopia, this paper explores the connections between poverty, migration and sex work and demonstrates that sex work provides a risky alternative, but often successful, path to independence for some rural-urban migrants. The paper concludes by offering recommendations for policies that seek to support young sex workers by enabling them to maintain their independence while seeking different employment.

Simulating SOC changes in 11 land use change chronosequences from the Brazilian Amazon with RothC and Century models

Land use and land cover changes in the Brazilian Amazon have major implications for regional and global carbon (C) cycling. Cattle pasture represents the largest single use (about 70%) of this once-forested land in most of the region. The main objective of this study was to evaluate the accuracy of the RothC and Century models at estimating soil organic C (SOC) changes under forest-to-pasture conditions in the Brazilian Amazon. We used data from 11 site-specific 'forest to pasture' chronosequences with the Century Ecosystem Model (Century 4.0) and the Rothamsted C Model (RothC 26.3). The models predicted that forest clearance and conversion to well managed pasture would cause an initial decline in soil C stocks (0-20 cm depth), followed in the majority of cases by a slow rise to levels exceeding those under native forest. One exception to this pattern was a chronosequence in Suia-Missu, which is under degraded pasture. In three other chronosequences the recovery of soil C under pasture appeared to be only to about the same level as under the previous forest. Statistical tests were applied to determine levels of agreement between simulated SOC stocks and observed stocks for all the sites within the 11 chronosequences. The models also provided reasonable estimates (coefficient of correlation = 0.8) of the microbial biomass C in the 0-10 cm soil layer for three chronosequences, when compared with available measured data. The Century model adequately predicted the magnitude and the overall trend in delta C-13 for the six chronosequences where measured 813 C data were available. This study gave independent tests of model performance, as no adjustments were made to the models to generate outputs. Our results suggest that modelling techniques can be successfully used for monitoring soil C stocks and changes, allowing both the identification of current patterns in the soil and the projection of future conditions. Results were used and discussed not only to evaluate soil C dynamics but also to indicate soil C sequestration opportunities for the Brazilian Amazon region. Moreover, modelling studies in these 'forest to pasture' systems have important applications, for example, the calculation of CO, emissions from land use change in national greenhouse gas inventories. (0 2007 Elsevier B.V. All rights reserved.

Predicted soil organic carbon stocks and changes in the Brazilian Amazon between 2000 and 2030

Currently we have little understanding of the impacts of land use change on soil C stocks in the Brazilian Amazon. Such information is needed to determine impacts'6n the global C cycle and the sustainability of agricultural systems that are replacing native forest. The aim of this study was to predict soil carbon stocks and changes in the Brazilian Amazon during the period between 2000 and 2030, using the GEFSOC soil carbon (C) modelling system. In order to do so, we devised current and future land use scenarios for the Brazilian Amazon, taking into account: (i) deforestation, rates from the past three decades, (ii) census data on land use from 1940 to 2000, including the expansion and intensification of agriculture in the region, (iii) available information on management practices, primarily related to well managed pasture versus degraded pasture and conventional systems versus no-tillage systems for soybean (Glycine max) and (iv) FAO predictions on agricultural land use and land use changes for the years 2015 and 2030. The land use scenarios were integrated with spatially explicit soils data (SOTER database), climate, potential natural vegetation and land management units using the recently developed GEFSOC soil C modelling system. Results are presented in map, table and graph form for the entire Brazilian Amazon for the current situation (1990 and 2000) and the future (2015 and 2030). Results include soil organic C (SOC) stocks and SOC stock change rates estimated by three methods: (i) the Century ecosystem model, (ii) the Rothamsted C model and (iii) the intergovernmental panel on climate change (IPCC) method for assessing soil C at regional scale. In addition, we show estimated values of above and belowground biomass for native vegetation, pasture and soybean. The results on regional SOC stocks compare reasonably well with those based on mapping approaches. The GEFSOC system provided a means of efficiently handling complex interactions among biotic-edapho-climatic conditions (> 363,000 combinations) in a very large area (similar to 500 Mha) such as the Brazilian Amazon. All of the methods used showed a decline in SOC stock for the period studied; Century and RothC simulated values for 2030 being about 7% lower than those in 1990. Values from Century and RothC (30,430 and 25,000 Tg for the 0-20 cm layer for the Brazilian Amazon region were higher than those obtained from the IPCC system (23,400 Tg in the 0-30 cm layer). Finally; our results can help understand the major biogeochemical cycles that influence soil fertility and help devise management strategies that enhance the sustainability of these areas and thus slow further deforestation. (C) 2007 Elsevier B.V. All rights reserved.

Poverty, migration and sex work: youth transitions in Ethiopia

Despite an emerging body of work on youth transitions, research has yet to explore the often unconventional routes to adulthood for young people marginalised through poverty. By drawing on interviews with 60 young commercial sex workers in Ethiopia, this paper explores the connections between poverty, migration and sex work and demonstrates that sex work provides a risky alternative, but often successful, path to independence for some rural-urban migrants. The paper concludes by offering recommendations for policies that seek to support young sex workers by enabling them to maintain their independence while seeking different employment.

Threshold effects in price transmission: The case of Brazilian wheat, maize, and soya prices

Recent studies into price transmission have recognized the important role played by transport and transaction costs. Threshold models are one approach to accommodate such costs. We develop a generalized Threshold Error Correction Model to test for the presence and form of threshold behavior in price transmission that is symmetric around equilibrium. We use monthly wheat, maize, and soya prices from the United States, Argentina, and Brazil to demonstrate this model. Classical estimation of these generalized models can present challenges but Bayesian techniques avoid many of these problems. Evidence for thresholds is found in three of the five commodity price pairs investigated.

The role of food standards in international trade: evidence from Brazilian beef exports to the EU market

The study reviews the literature on global chain governance and food standards to allow for an assessment of Brazilian beef exports to the European Union. The empirical approach employed is based on company case studies. The results suggest that the Brazilian beef chain has little choice but to adapt to market changes as standards evolve. Costs of compliance for meeting international food standards reduce Brazil's comparative advantage. At the same time, changes in the nature of demand have created the need for a more integrated supply chain in order to enhance confidence in Brazil's beef production and processing abroad.