A model for predicting dissolved organic carbon distribution in a reservoir water using fluorescence spectroscopy

A number of water treatment works (WTW) in the north of England (UK) have experienced problems in reducing the dissolved organic carbon (DOC) present in the water to a sufficiently low level. The problems are experienced in autumn/ winter when the colour increases and the coagulant dose at the WTW needs to be increased in order to achieve sufficient colour removal. However, the DOC content of the water varies little throughout the year. To investigate this further, the water was fractionated using resin adsorption techniques into its hydrophobic (fulvic and humic acid fractions) and hydrophilic (acid and non-acid fractions) components. The fractionation process yields useful information on the changing concentration of each fraction but is time consuming and labour intensive. Here, a method of rapidly determining fraction concentration was developed using fluorescence spectroscopy. The model created used synchronous spectra of fractionated material compared against bulk water spectra and predicted the fraction concentrations to within 10% for a specific water. The model was unable to predict fraction concentrations for waters from a different watershed

Electron Self-Trapping in Ge\u3csub\u3e2\u3c/sub\u3e Se\u3csub\u3e3\u3c/sub\u3e and Its Role in Ag and Sn Incorporation

We present a set of density functional theory (DFT) calculations on the electronic structure of Ag and Sn in Ge2 Se3 in a periodic model. We show that electron self-trapping is a persistent feature in the presence of many defects. Ag and Sn autoionize upon entering Ge2 Se3 becoming Ag+ and Sn2+ , respectively, and the freed electrons self trap at the lowest energy site. Both Ag and Sn can substitute for Ge, and we present formation energies as a function of Fermi level that show that Sn can substantially alter the incorporation of Ag into the Ge2Se3 network

Designing and evaluating complex interventions to improve health care

Complex interventions are “built up from a number of components, which may act both independently and interdependently.”1 2 Many health service activities should be considered as complex. Evaluating complex interventions can pose a considerable challenge and requires a substantial investment of time. Unless the trials illuminate processes and mechanisms they often fail to provide useful information. If the result is negative, we are left wondering whether the intervention is inherently ineffective (either because the intervention was inadequately developed or because all similar interventions are ineffective), whether it was inadequately applied or applied in an inappropriate context, or whether the trial used an inappropriate design, comparison groups or outcomes. If there is a positive effect, it can be hard to judge how the results of the trial might be applied to a different context (box 1)

Factors influencing the choice of shared bicycles and shared electric bikes in Beijing

AbstractChina leads the world in both public bikeshare and private electric bike (e-bike) growth. Current trajectories indicate the viability of deploying large-scale shared e-bike (e-bikeshare) systems in China. We employ a stated preference survey and multinomial logit to model the factors influencing the choice to switch from an existing transportation mode to bikeshare or e-bikeshare in Beijing. Demand is influenced by distinct sets of factors: the bikeshare choice is most sensitive to measures of effort and comfort while the e-bikeshare choice is more sensitive to user heterogeneities. Bikeshare demand is strongly negatively impacted by trip distance, temperature, precipitation, and poor air quality. User demographics however do not factor strongly on the bikeshare choice, indicating the mode will draw users from across the social spectrum. The e-bikeshare choice is much more tolerant of trip distance, high temperatures and poor air quality, though precipitation is also a highly negative factor. User demographics do play a significant role in e-bikeshare demand. Analysis of impact to the existing transportation system finds that both bikeshare and e-bikeshare will tend to draw users away from the “unsheltered modes”, walk, bike, and e-bike. Although it is unclear if shared bikes are an attractive “first-and-last-mile solution”, it is clear that e-bikeshare is attractive as a bus replacement

The Vulnerability of Groundwater Resources to Climate Change in Timor-Leste. Prepared for the Australian Government Department of Climate Change and Enerfy Efficiency by B. Mayers, R. Fisher, T. Paul P. Wurm. A. Campbell, Research Institute for the Enviro

This report is part of a two part study of the vulnerability of Timor-Leste’s ground water resources, and those who use them, to predicted climate change.In this part of the study by Charles Darwin University (CDU) we focus on potential impact and adaptive capacity to address the vulnerability of Districts to water availability, and provide recommendations for water management. The second part of the study, by Geosciences Australia and presented separately, investigates the biophysical vulnerability of Timor Leste (of the aquifers) to climate change.This report uses a mixed methods approach including:• Review of current climate change predictions• Review of information about aquifer characteristics, provided by the GA study• Assessment of exposure of aquifers to pressure by groundwater users, by reviewing population distribution and growth• Evaluation of adaptive capacity of groundwater users, using census data on indicators of wealth, and field interviews about use and management of water resources.Using these methods we identify priority areas for action in water management and current and potential adaptation options. These options link readily to the National Adaptation Programmes of Action for Timor-Leste (NAPA), and we have also ranked them broadly in terms of predicted cost of implementation.Timor-Leste is a small island developing state, located in the eastern part of the lesser Sunda Islands archipelago. Topography is rugged, with the central mountains of the island reaching altitudes of almost 3000m. The climate is monsoonal, and annual rainfall varies with elevation and aspect, from less than 1000mm in some coastal areas to over 2500mm in the wettest high altitude areas. Timor-Leste has a complex geology and much of the bedrock is sedimentary calcareous rock with shallow soils of low water holding capacity, high alkalinity and low nutrient content.According to the national census, in 2010 Timor-Leste had a population of 1.07 million. Population growth is high (2.4%), fertility rate is high (5.7 births for each fertile aged woman) and the population is relatively young (41% under 14 years, 54% between 15-66 years, and about 5% over 65 years).Already, water insecurity is widespread in Timor-Leste and is a major limitation of food security and livelihoods. Low-input agriculture is the main economic activity in Timor-Leste, with over 86% of households involved in subsistence farming. The main staple crops are rice, maize and cassava, with the limited rice production on the coastal plains fed by gravity irrigation and maize widely grown on the uplands.Geoscience Australia has classified aquifer types in Timor-Leste according to geology and “prospectivity”, i.e. potential flow rates or yields. The major aquifer types in Timor-Leste are:• Sedimentary aquifers with intergranular porosity, which have potential to hold large amounts of groundwater. Alluvial sedimentary aquifers have potential to be high yielding aquifers, with higher yield associated with greater porosity where sediments are more well-sorted (e.g. Dili).• Limestone karstic aquifers with fissured porosity are associated with many springs fed by groundwater and are sensitive to rainfall. In limestone areas, groundwater recharge, storage and yield are affected by the age of the system which determines whether fissures and channels have formed (e.g. in and around Baucau).• Fractured rock aquifers with localised porosity are low yielding and usually only sufficient for household use and animal watering. There is little or no porosity and groundwater is stored in existing fractures, with new channels not becoming larger with time (e.g. Lequidoe in Aileu District).A substantial proportion (about 33%) of the population live on high yielding sedimentary aquifers, particularly on the coast, such as in Dili District, however, most of the population (44%) live on localised aquifers in the highlands (approximately equally on high yielding karst and low yielding localised fractured rock aquifers aquifers).Uncertainty in climate change projections for Timor-Leste is relatively high because Timor-Leste is a similar in size to the grid cells of the models used for projections, has variable topography and little climatic data with which to test the validity of the models that underpin the projections.The most recent climate projections for Timor-Leste have been published by the Pacific Climate Change Science Program (www.pacificclimatechangescience.org). These projections include:• warming of average air and sea temperatures (by 0.4-1.0oC by 2030 under a high emissions scenario);• decrease in dry season and increase in wet season rainfall;• extreme rainfall events to occur more frequently;• decrease in frequency and increase in high intensity cyclones;• sea level rise will continue (by 6-15cm by 2030 under a high emissions scenario)• ocean acidification will continue.Impacts of climate change are discussed within the following framework:Exposure of groundwater resources to climate change were derived from prospectivity of aquifers as determined by Geoscience Australia. Sensitivity of groundwater resources was mapped by overlaying relative aquifer yield and modelled annual rainfall. Areas along the central northern coast and in Oecussi are expected to be particularly sensitive. Sensitivity was also considered in terms of population pressures, both density and rate of change.Potential impacts of climate change were a function of expected exposure to climate change and sensitivity to those changes. High potential impact was identified in several areas on low yielding, localised aquifers: Liquica District, with low rainfall west of Dili; the Districts of Ainaro, Aileu, Bobonaro, and Ermera, with high and rapidly growing populations; Oecussi District, with high population growth and low rainfall. The major towns of Dili and Baucau can also be considered sites of high potential impacts because of high population densities and high population growth rates. This is despite having relatively high yielding aquifers: high yielding sedimentary aquifer in the case of Dili and high yielding fissured aquifer in the case of Baucau. In addition, the surrounding hills are underlain by low yielding fractured rock aquifers.Vulnerability to climate change is a product of potential impacts and adaptive capacity.High adaptive capacity can minimise the vulnerability of a community or nation in the face of high potential impacts. Adaptive capacity is influenced by many factors, including poverty, education, health and social capital. We derived some possible indicators of adaptive capacity using data from the national census and Demographic and Health Survey, and from field surveys at sites representing the main aquifer types. This investigation indicated higher vulnerability due to potentially low adaptive capacity in some Districts. Dili is wealthy compared with other Districts and this may represent relatively high capacity for adaptation. Other factors, such as implementation of some health programs and evidence of community management bodies, suggest high adaptive capacity in other Districts. Current adaptation strategies in some sites included cooperative management of water resources, moving temporarily when water sources became unavailable, carrying water, and collecting rainwater.In summary, the following adaptation options are recommended:1. Documentation and monitoring of ground water resources – to improve understanding of water availability;2. Integrated water harvesting and storage, and irrigation maintenance – to build local resilience and adaptive capacity;3. Agricultural diversification - to build resilience and adaptive capacity;4. Improving governance (policy and regulation) – to reduce waste and over use, to secure availability and access, and to increase adaptive capacity.The people of Timor-Leste face substantial challenges in coping with the variability of the current climate, and further challenges regarding the expected changes to climate and water availability. Options for adaptations to climate change should be considered in the context of food security and sustainable agriculture and natural resource management practices at community, landscape and national scales. The need for this broader framework is stipulated in the National Adaptation Programmes of Action for Timor-Leste (NAPA)

Dynamical Arrest in Attractive Colloids: The Effect of Long-Range Repulsion

We study gelation in suspensions of model colloidal particles with short-ranged attractive and long-ranged repulsive interactions by means of three-dimensional fluorescence confocal microscopy. At low packing fractions, particles form stable equilibrium clusters. Upon increasing the packing fraction the clusters grow in size and become increasingly anisotropic until finally associating into a fully connected network at gelation. We find a surprising order in the gel structure. Analysis of spatial and orientational correlations reveals that the gel is composed of dense chains of particles constructed from face-sharing tetrahedral clusters. Our findings imply that dynamical arrest occurs via cluster growth and association.Comment: Final version: Phys. Rev. Lett. 94, 208301 (2005

Evidence of B Cell Immune Responses to Acute Lymphoblastic Leukemia in Murine Allogeneic Hematopoietic Stem Cell Transplantation Recipients Treated with Donor Lymphocyte Infusion and/or Vaccination

These experiments explored mechanisms of control of acute lymphoblastic leukemia (ALL) following allogeneic hematopoietic stem cell transplantation using a murine model of MHC-matched, minor histocompatibility antigen–mismatched transplantation. The central hypothesis examined was that addition of active vaccination against leukemia cells would substantially increase the effectiveness of allogeneic donor lymphocyte infusion (DLI) against ALL present in the host after transplantation. Although vaccination did increase the magnitude of type I T cell responses against leukemia cells associated with DLI, it did not lead to substantial improvement in long-term survival. Analysis of immunologic mechanisms of leukemia progression demonstrated that the failure of vaccination was not because of antigen loss in leukemia cells. However, analysis of survival provided surprising findings that, in addition to very modest type I T cell responses, a B cell response that produced antibodies that bind leukemia cells was found in long-term survivors. The risk of death from leukemia was significantly lower in recipients that had higher levels of such antibodies. These studies raise the hypothesis that stimulation of B cell responses after transplantation may provide a novel way to enhance allogeneic graft-versus-leukemia effects associated with transplantation

If You Make it Free, Will They Come? Using a Physical Activity Accessibility Model to Understand the Use of a Free Children’s Recreation Pass

Background: Children’s sedentary lifestyles and low physical activity levels may be countered using population-level interventions. This study examines factors influencing the use of a free community-wide physical activity access pass for grade 5 students (G5AP). Methods: A natural experiment with longitudinal data collection. A sample of 881 children completed the 9-month follow-up survey self-reporting where they used the G5AP. Two analyses were conducted: Getis-Ord GI* geographic cluster analysis of the spatial distribution of users, and logistic regression examining the relationship between use and accessibility (informational, economic, and geographic) and mobility options, while accounting for intrapersonal and interpersonal factors. Results: Overall, 44.9% of children used the G5AP with clusters of high use in urban areas and low use in the suburbs. Other factors significantly related to G5AP included gender (girls), informational accessibility (active recruitment), economic accessibility (median household income), geographic accessibility (facilities within 1.6 km of home), and mobility options (access to Boys & Girls Club bus). Conclusions: This study found that a diverse population of children used the G5AP. To continue being successful, community-based physical activity interventions need to ensure that the intervention increases geographic, economic, and informational accessibility and provides mobility options that are available to the target population