862 research outputs found
Modeling of Desalination Concentrate Storage Options for Future Recovery and Use
Ciudad Juárez, Chihuahua, a rapidly growing city across the Rio Grande from El Paso, Texas with a 2005 population in excess of 1.2 million, relies exclusively on ground water from an aquifer known as the Hueco Bolson. The aquifer’s fresh water is being depleted and it is degrading in quality due to the lateral inflow of brackish water. Although the Hueco Bolson’s fresh water is diminishing, it still contains a considerable quantity of brackish water. This paper defines the feasibility of using desalination technology in conjunction with concentrate storage to extend the ‘life’ of the Juárez portion of the Hueco Bolson. Well injection of the concentrate was analyzed based on the premise that the cones of depression created by well pumping could provide a storage area for the concentrate. So doing would enable the brackish concentrate to be ‘stored’ for future use when advances in desalination technology will render the stored concentrate into an economically recoverable resource , unlike evaporation ponds that result in the permanent loss of water due to vaporization. The research team used a combination of three software systems for this portion of the analysis: a ground water modeling software, a mass transport extension to the ground water modeling software, and GIS software to facilitate the visualization of model outputs. The technical report on which this paper is based was authored by Turner and Hamlyn (2004)
Inflammation and microbial translocation in primary HIV infection and the effect of short-course antiretroviral therapy
The duality of ocean acidification as a resource and a stressor
Ecologically dominant species often define ecosystem states, but as human disturbances intensify, their subordinate counterparts increasingly displace them. We consider the duality of disturbance by examining how environmental drivers can simultaneously act as a stressor to dominant species and as a resource to subordinates. Using a model ecosystem, we demonstrate that CO2-driven interactions between species can account for such reversals in dominance; i.e., the displacement of dominants (kelp forests) by subordinates (turf algae). We established that CO2 enrichment had a direct positive effect on productivity of turfs, but a negligible effect on kelp. CO2 enrichment further suppressed the abundance and feeding rate of the primary grazer of turfs (sea urchins), but had an opposite effect on the minor grazer (gastropods). Thus, boosted production of subordinate producers, exacerbated by a net reduction in its consumption by primary grazers, accounts for community change (i.e., turf displacing kelp). Ecosystem collapse, therefore, is more likely when resource enrichment alters competitive dominance of producers, and consumers fail to compensate. By recognizing such duality in the responses of interacting species to disturbance, which may stabilize or exacerbate change, we can begin to understand how intensifying human disturbances determine whether or not ecosystems undergo phase shifts
Ambient interaction and situational influence: case studies in public sites.
An audience's direct physical intervention is widely believed to be instrumental in the field of interactive art. However, this long established expectation faces new challenges through the increasing accessibility of a growing diversity of interactive technologies and ubiquitous smart media. Such innovations are often fully integrated components of interactive public artworks, many of which do not directly involve audiences or individuals as key agents in the functional or aesthetic realisation of the work. Based on three case studies of interactive artworks in public places, this article identifies an important characteristic of interactivity in interactive art, through the largely unexplored concept of 'Ambient Interaction' in which artworks are embodied and enacted through environmental conditions and situational influences rather than exclusively through people's intentional and direct physical engagement
Platelet count and transfusion requirements during moderate or severe postpartum haemorrhage
Limited data exist on platelet transfusion during postpartum haemorrhage. We retrospectively analysed a consecutive cohort from a single centre of 347 women with moderate or severe postpartum haemorrhage, transfused according to national guidelines. Twelve (3%) women required a platelet transfusion. There were no differences between women who did and did not receive platelets with respect to age, mode of initiation of labour or mode of delivery. Women receiving a platelet transfusion had a lower median (IQR [range]) platelet count at study entry than women who did not receive platelets before haemorrhage (135 (97–175 [26–259])×109.l−1 vs 224 (186–274 [91–1006])×109.l−1), respectively), and at diagnosis of postpartum haemorrhage (median 114 (78–153 [58–238])×109.l−1 vs 193 (155–243 [78–762])×109.l−1 respectively). Six women were thrombocytopenic pre-delivery. The cause of haemorrhage that was associated with the highest rate of platelet transfusion was placental abruption, with three of 14 women being transfused. If antenatal thrombocytopenia or consumptive coagulopathy were not present, platelets were only required for haemorrhage > 5000 ml. Early formulaic platelet transfusion would have resulted in many women receiving platelets unnecessarily. Using current guidelines, the need for platelet transfusion is uncommon without antenatal thrombocytopenia, consumptive coagulopathy or haemorrhage > 5000 ml. We found no evidence to support early fixed-ratio platelet transfusion
A structured collaborative approach to intervention design using a modified intervention mapping approach: a case study using the Management and Interventions for Asthma (MIA) project for South Asian children
Background:
To describe how using a combined approach of community-based participatory research and intervention mapping principles could inform the development of a tailored complex intervention to improve management of asthma for South Asian (SA) children; Management and Interventions for Asthma (MIA) study.
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Methods:
A qualitative study using interviews, focus groups, workshops, and modified intervention mapping procedures to develop an intervention planning framework in an urban community setting in Leicester, UK. The modified form of intervention mapping (IM) included: systematic evidence synthesis; community study; families and healthcare professionals study; and development of potential collaborative intervention strategies. Participants in the community study were 63 SA community members and 12 key informants; in-depth semi-structured interviews involved 30 SA families, 14 White British (WB) families and 37 Healthcare Professionals (HCPs) treating SA children living with asthma; prioritisation workshops involved 145 SA, 6 WB and 37 HCP participants; 30 participants in finalisation workshops.
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Results:
Two key principles were utilised throughout the development of the intervention; community-based participatory research (CBPR) principles and intervention mapping (IM) procedures. The CBPR approach allowed close engagement with stakeholders and generated valuable knowledge to inform intervention development. It accounted for diverse perceptions and experiences with regard to asthma and recognised the priorities of patients and their families/caregivers for service improvement. The ‘ACT on Asthma’ programme was devised, comprising four arms of an intervention strategy: education and training, clinical support, advice centre and raising awareness, to be co-ordinated by a central team.
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Conclusions:
The modified IM principles utilised in this study were systematic and informed by theory. The combined IM and participatory approach could be considered when tailoring interventions for other clinical problems within diverse communities. The IM approach to intervention development was however resource intensive. Working in meaningful collaboration with minority communities requires specific resources and a culturally competent methodology
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Spatial and temporal variability of the concentration field from localized releases in a regular building array
Spatial and temporal fluctuations in the concentration field from an ensemble of continuous point-source releases in a regular building array are analyzed from data generated by direct numerical simulations. The release is of a passive scalar under conditions of neutral stability. Results are related to the underlying flow structure by contrasting data for an imposed wind direction of 0 deg and 45 deg relative to the buildings. Furthermore, the effects of distance from the source and vicinity to the plume centreline on the spatial and temporal variability are documented. The general picture that emerges is that this particular geometry splits the flow domain into segments (e.g. “streets” and “intersections”) in each of which the air is, to a first approximation, well mixed. Notable exceptions to this general rule include regions close to the source, near the plume edge, and in unobstructed channels when the flow is aligned. In the oblique (45 deg) case the strongly three-dimensional nature of the flow enhances mixing of a scalar within the canopy leading to reduced temporal and spatial concentration fluctuations within the plume core. These fluctuations are in general larger for the parallel flow (0 deg) case, especially so in the long unobstructed channels. Due to the more complex flow structure in the canyon-type streets behind buildings, fluctuations are lower than in the open channels, though still substantially larger than for oblique flow. These results are relevant to the formulation of simple models for dispersion in urban areas and to the quantification of the uncertainties in their predictions
First recorded eruption of Nabro volcano, Eritrea, 2011
We present a synthesis of diverse observations of the first recorded eruption of Nabro volcano, Eritrea, which began on 12 June 2011. While no monitoring of the volcano was in effect at the time, it has been possible to reconstruct the nature and evolution of the eruption through analysis of re- gional seismological and infrasound data and satellite remote sensing data, supplemented by petrological analysis of erupted products and brief field surveys. The event is notable for the comparative rarity of recorded historical eruptions in the region and of caldera systems in general, for the prodi- gious quantity of SO2 emitted into the atmosphere and the significant human impacts that ensued notwithstanding the low population density of the Afar region. It is also relevant in understanding the broader magmatic and tectonic signifi- cance of the volcanic massif of which Nabro forms a part and which strikes obliquely to the principal rifting directions in the Red Sea and northern Afar. The whole-rock compositions of
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the erupted lavas and tephra range from trachybasaltic to trachybasaltic andesite, and crystal-hosted melt inclusions contain up to 3,000 ppm of sulphur by weight. The eruption was preceded by significant seismicity, detected by regional networks of sensors and accompanied by sustained tremor. Substantial infrasound was recorded at distances of hundreds to thousands of kilometres from the vent, beginning at the onset of the eruption and continuing for weeks. Analysis of ground deformation suggests the eruption was fed by a shal- low, NW–SE-trending dike, which is consistent with field and satellite observations of vent distributions. Despite lack of prior planning and preparedness for volcanic events in the country, rapid coordination of the emergency response miti- gated the human costs of the eruption
A cost effectiveness analysis of the preferred antidotes for acute paracetamol poisoning patients in Sri Lanka
Background: Acute paracetamol poisoning is a rapidly increasing problem in Sri Lanka. The antidotes are expensive and yet no health economic evaluation has been done on the therapy for acute paracetamol poisoning in the developing world. The aim of this study is to determine the cost effectiveness of using N-acetylcysteine over methionine in the management of acute paracetamol poisoning in Sri Lanka. Methods:Economic analysis was applied using public healthcare system payer perspective. Costs were obtained from a series of patients admitted to the National Hospital of Sri Lanka with a history of acute paracetamol overdose. Evidence on effectiveness was obtained from a systematic review of the literature. Death due to hepatotoxicity was used as the primary outcome of interest. Analysis and development of decision tree models was done using Tree Age Pro 2008. Results: An affordable treatment threshold of Sri Lankan rupees 1,537,120/death prevented was set from the expected years of productive life gained and the average contribution to GDP. A cost-minimisation analysis was appropriate for patients presenting within 10 hours and methionine was the least costly antidote. For patients presenting 10-24 hours after poisoning, n-acetylcysteine was more effective and the incremental cost effectiveness ratio of Sri Lankan rupees 316,182/life saved was well under the threshold. One-way and multi-way sensitivity analysis also supported methionine for patients treated within 10 hours and n-acetylcysteine for patients treated within 10-24 hours as preferred antidotes.Conclusions: Post ingestion time is an important determinant of preferred antidotal therapy for acute paracetamol poisoning patients in Sri Lanka. Using n-acetylcysteine in all patients is not cost effective. On economic grounds, methionine should become the preferred antidote for Sri Lankan patients treated within 10 hours of the acute ingestion and n-acetylcysteine should continue to be given to patients treated within 10-24 hours
A method for automatic segmentation and splitting of hyperspectral images of raspberry plants collected in field conditions
Abstract Hyperspectral imaging is a technology that can be used to monitor plant responses to stress. Hyperspectral images have a full spectrum for each pixel in the image, 400–2500 nm in this case, giving detailed information about the spectral reflectance of the plant. Although this technology has been used in laboratory-based controlled lighting conditions for early detection of plant disease, the transfer of such technology to imaging plants in field conditions presents a number of challenges. These include problems caused by varying light levels and difficulties of separating the target plant from its background. Here we present an automated method that has been developed to segment raspberry plants from the background using a selected spectral ratio combined with edge detection. Graph theory was used to minimise a cost function to detect the continuous boundary between uninteresting plants and the area of interest. The method includes automatic detection of a known reflectance tile which was kept constantly within the field of view for all image scans. A method to split images containing rows of multiple raspberry plants into individual plants was also developed. Validation was carried out by comparison of plant height and density measurements with manually scored values. A reasonable correlation was found between these manual scores and measurements taken from the images (r2 = 0.75 for plant height). These preliminary steps are an essential requirement before detailed spectral analysis of the plants can be achieved
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