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    ABSTRACT: Tour or trip chain based travel analysis has been a feature of transportation research for several decades, but has largely been the preserve of developed countries. Furthermore, the important associations between urban form and trip-chaining behaviour have received little attention. Based on detailed land use data and an activity dairy survey for workers in Beijing, China, this paper investigates how socio-demographic attributes of households, individuals and urban form characteristics at both residence and workplace, correlate with the tour-based travel decision process. We focus on tour frequency, tour scheduling (type and order of stops made) and tour interdependence mechanisms. Empirical results show that socio-demographic attributes and commuting time strongly correlate with tour decisions, but that there is no significant gender difference in tour frequency, as seen in developed countries, although women tend to make more stops within a tour. Urban form characteristics at home and at workplace are significantly associated with tour frequency, but differ with respect to tour complexity. For example, higher residential density is associated with more home-based tours with fewer stops, while mixed land use at workplaces having higher density and accessibility is associated with more stops within one work tour, or a more complex tour pattern. The research also reveals, for the first time, a tour interdependence effect for workers who undertake multiple tours.
    Habitat International 07/2014; 43:263–273.
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    ABSTRACT: Developing low carbon cities is a key goal of 21st century planning, and one that can be supported by a better understanding of the factors that shape travel behaviour, and resulting carbon emissions. Understanding travel based carbon emissions in mega-cities is vital, but city size and often a lack of required data, limits the ability to apply linked land use, transport and tactical transport models to investigate the impact of policy and planning interventions on travel and emissions. Here, we adopt an alternative approach, through the development of a static spatial microsimulation of people’s daily travel behaviour. Using Beijing as a case study, we first derive complete activity-travel records for 1026 residents from an activity diary survey. Then, using the 2000 population census data at the sub-district level, we apply a simulated annealing algorithm to create a synthetic population at fine spatial scale for Beijing and spatially simulate the population’s daily travel, including trip distance and mode choice at the sub-district scale. Finally, we estimate transport CO2 emission from daily urban travel at the disaggregate level in urban Beijing.
    Computers Environment and Urban Systems 05/2014; 45:78–88.
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    ABSTRACT: This study focuses on identifying the future trends and spatial concentrations of morbidities in the English elderly population. The morbidities to be estimated are: coronary heart disease; strokes; diabetes; cancer; respiratory illnesses and arthritis in the 60 year and older household residential population. The technique used is a spatial microsimulation of the elderly population of local authorities in England using data from the 2001 Census and the English Longitudinal Study of Ageing. The longitudinal nature of the microsimulated population is then used to estimate the morbidity prevalences for local authorities in 2010/2011. With this knowledge, planners will be able to focus the available health and care resources in those areas with greatest need. For most of these morbidities, there is evidence of a strong correlation between the type of authority and the estimated prevalence rates.
    Health & Place 05/2014; 27:176–185.
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    ABSTRACT: The evolution in number, area and volume of ice-marginal lakes in western Greenland is very poorly documented or understood. It is important to understand ice-marginal lake evolution because they provide an element of meltwater retention, affect ice-margin character and behaviour, and potentially glacier dynamics. This study uses repeat satellite imagery acquired between 1987 and 2010 to reveal a net 44 % (± 6.5 %) increase in the number of lakes, a net 20 % (± 6.5 %) expansion in total lake surface area and an increase of 12% (± 3.3 %) in the estimated volume of meltwater retained along a 1300 km length of the ice margin in western Greenland. Whilst ~ 12 % (± 1.6 %) of the ice margin holds lakes at any one time there is considerable complexity in lake evolution; many lakes have coalesced, drained partially or fully, or become detached from the ice margin. The total lake volume equates to 144 % of the annual runoff combined from Gothab and Jakobshavn hydrological catchments. The rate of increase in meltwater retention between 1987 and 2010 was similar to the rate of increase in ice sheet surface runoff over the same time period. If the study region is representative of the whole Greenland ice sheet margin then as a first-order estimate ~ 5 % of the increased runoff over the last 25 years has been intercepted enroute to the oceans by the increased ice-marginal lake capacity. Interactions between these ice-marginal lakes, the western Greenland ice sheet and climate should be determined to provide insight into future land-terminating ice-marginal conditions, runoff retention and meltwater and sediment fluxes to the oceans.
    Global and Planetary Change 05/2014;
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    ABSTRACT: Understanding the ecohydrological responses of peatlands to climate change is particularly challenging over the late Holocene owing to the confounding influence of anthropogenic activity. To address this, a core spanning the last ∼2400 years from a raised bog in northern England was analysed using a comprehensive suite of proxy methods in an attempt to elucidate the drivers of change. A testate amoebae-based transfer function was used to quantitatively reconstruct changes in water table depth, supported by humification analysis and a plant macrofossil-derived hydroclimatic index. Pollen and plant macrofossil data were used to examine regional and local vegetation change, and human impacts were inferred from charcoal and geochemistry. Chronological control was achieved through a Bayesian age-depth model based on AMS radiocarbon dates and spheroidal carbonaceous particles, from which peat and carbon accumulation rates were calculated. Phases of both increased and decreased bog surface wetness (inferred effective precipitation) are present, with dry phases at c. AD 320–830, AD 920–1190 and AD 1850–present, and a marked period of increased effective precipitation at c. AD 1460–1850. Coherence with other records from across Northern Europe suggests that these episodes are primarily driven by allogenic climatic change. Periods of high bog surface wetness correspond to the Wolf, Spörer and Maunder sunspot activity minima, suggesting solar forcing was a significant driver of climate change over the last ∼1000 years. Following the intensification of agriculture and industry over the last two centuries, the combined climatic and anthropogenic forcing effects become increasingly difficult to separate due to increases in atmospheric deposition of anthropogenically derived pollutants, fertilising compounds, and additions of wind-blown soil dust. We illustrate the need for multiproxy approaches based on high-resolution palaeoecology and geochemistry to examine the recent trajectories of peatlands.
    Quaternary Science Reviews 01/2014; 84:65-85.
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    ABSTRACT: There is concern that ecosystem services provided by blanket peatlands have come under threat due to increasing degradation. Blanket peatlands are subject to a wide range of drivers of degradation and are topographically variable. As a result, many degradation forms can develop, including those resulting from eroding artificial drainage, incising gullies and areas of bare peat. Many degraded blanket peatlands have undergone restoration measures since the turn of the century. However, there has been little formal communication of the techniques used and their success. Using practitioner knowledge and a review of the available literature, this paper discusses the methodologies used for restoring sloping blanket peatlands. It then considers current understanding of the impact of restoration on blanket peatland ecosystem services. There is a paucity of research investigating impacts of several common restoration techniques and much more is needed if informed management decisions are to be made and funding is to be appropriately spent. Where data are available we find that restoration is largely beneficial to many ecosystem services, with improvements being observed in water quality and ecology. However, the same restoration technique does not always result in the same outcomes in all locations. The difference in response is predominantly due to the spatial and temporal heterogeneity inherent in all blanket peatlands. Peatland practitioners must take this variability into account when designing restoration strategies and monitoring impact.
    Journal of Environmental Management 01/2014; 133:193–205.
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    ABSTRACT: Catchment-scale land-use change is recognised as a major threat to aquatic biodiversity and ecosystem functioning globally. In the UK uplands rotational vegetation burning is practised widely to boost production of recreational game birds, and while some recent studies have suggested burning can alter river water quality there has been minimal attention paid to effects on aquatic biota. We studied ten rivers across the north of England between March 2010 and October 2011, five of which drained burned catchments and five from unburned catchments. There were significant effects of burning, season and their interaction on river macroinvertebrate communities, with rivers draining burned catchments having significantly lower taxonomic richness and Simpson's diversity. ANOSIM revealed a significant effect of burning on macroinvertebrate community composition, with typically reduced Ephemeroptera abundance and diversity and greater abundance of Chironomidae and Nemouridae. Grazer and collector-gatherer feeding groups were also significantly less abundant in rivers draining burned catchments. These biotic changes were associated with lower pH and higher Si, Mn, Fe and Al in burned systems. Vegetation burning on peatland therefore has effects beyond the terrestrial part of the system where the management intervention is being practiced. Similar responses of river macroinvertebrate communities have been observed in peatlands disturbed by forestry activity across northern Europe. Finally we found river ecosystem changes similar to those observed in studies of wild and prescribed forest fires across North America and South Africa, illustrating some potentially generic effects of fire on aquatic ecosystems.
    PLoS ONE 11/2013; 8(11):e81023.
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    ABSTRACT: Less than half of anthropogenic carbon emissions are accumulating in the atmosphere, due to large net fluxes into both the oceans and the land (Le Queré et al., 2012). The land sink in particular has increased markedly, doubling in strength since the 1960's, to reach 26 petagrams of carbon in the latest decade. However, the location and drivers of this large terrestrial sink are still relatively poorly constrained by atmospheric measurements (Ciais et al. 2013). Pan et al. (2011) recently utilised >1 million forest inventory plots to provide summaries of forest carbon stocks, and the first global bottom-up estimates of carbon fluxes for the world's forest biomes for the period 1990-2007. One key result was that almost all the residual global terrestrial carbon sink (i.e. carbon uptake after accounting for land use change), some 2.4 ± 0.4 Pg of carbon per year, is located in the world's established forests (Pan et al., 2011). The sink is distributed worldwide, with globally significant net fluxes into boreal and temperate forests, and a large sink in intact tropical forest, albeit with large uncertainty. Furthermore, Pan et al. (2011) showed that this tropical intact forest sink - may have faded from an estimated annual 1.3 ± 0.4 Pg C in the 1990's to 1.0 ± 0.5 Pg C for 2000-2007. The tropical intact sink is offset by a net land-use emission (1.5 Pg C yr(-1) [1990-1999]) declining to 1.1 Pg C yr(-1) [2000-2007]), and as a consequence aircraft measurements and inverse modelling studies indicate the tropics to be close to neutral in terms of net carbon fluxes (reviewed by Ciais et al. 2013). While the intact tropical forest sink values represent updates from similar values published previously (e.g., Lewis et al., 2009a), the fact that almost the entire residual terrestrial carbon sink is accounted for by the forests of the world was a notable discovery. Evidence from the ground now points to established forests being a net sink across almost every major forest region, including all extra-tropical forest regions analysed. This article is protected by copyright. All rights reserved.
    Global Change Biology 10/2013;
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    ABSTRACT: To project the ethnic-group populations of local authorities in England to 2051, estimates of ethnic-specific fertility rates were needed. In the absence of ethnic information on birth records, we developed indirect estimation methods that use a combination of vital statistics, the census (both microdata and aggregate tables), and survey data (Labour Force Survey). We estimated age-specific and total fertility rates successively for five broad ethnic groups encompassed by all data-sets, and for eight ethnic groups encompassed by the 1991 and 2001 Censuses for England. We then used census data to disaggregate the estimates to the 16 ethnic groups required for the subnational projections and the Hadwiger function to estimate single-year-of-age estimates. We estimated the uncertainty around the fertility estimates and used a logistic model to project rates to 2021, after which we assumed rates would remain constant.
    Population Studies 07/2013;
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    ABSTRACT: Glacier retreat is occurring across the world, and associated river ecosystems are expected to respond more rapidly than those in flowing waters in other regions. The river environment directly downstream of a glacier snout is characterised by extreme low water temperature and unstable channel sediments but these habitats may become rarer with widespread glacier retreat. In these extreme environments food web dynamics have been little studied, yet they could offer opportunities to test food web theories using highly resolved food webs owing to their low taxonomic richness. This study examined the interactions of macroinvertebrate and diatom taxa in the Ödenwinkelkees river, Austrian central Alps between 2006 and 2011. The webs were characterised by low taxon richness (13-22), highly connected individuals (directed connectance up to 0.19) and short mean food chain length (2.00-2.36). The dominant macroinvertebrates were members of the Chironomidae genus Diamesa and had an omnivorous diet rich in detritus and diatoms as well as other Chironomidae. Simuliidae (typically detritivorous filterers) had a diet rich in diatoms but also showed evidence of predation on Chironomidae larvae. Food webs showed strong species-averaged and individual size structuring but mass-abundance scaling coefficients were larger than those predicted by metabolic theory, perhaps due to a combination of spatial averaging effects of patchily distributed consumers and resources, and/or consumers deriving unquantified resources from microorganisms attached to the large amounts of ingested rock fragments. Comparison of food web structural metrics with those from 62 published river webs suggest these glacier-fed river food web properties were extreme but in line with general food web scaling predictions, a finding which could prove useful to forecast the effects of anticipated future glacier retreat on the structure of aquatic food webs.
    PLoS ONE 04/2013; 8(4):e60899.
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