222 research outputs found

    Pollutant advective spreading in beach sand exposed to high-energy tides

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    yesThis paper presents field measurements in which dye solute was injected into coastal sand to investigate contaminant advection in intertidal beach sand. The measurements show the pathways of a contaminated plume in the unsaturated zone during both the flood and ebb tides. A prescribed amount of dye tracer solution was directly injected through the topsoil, with average porosity 0.3521±0.01, at predetermined locations of the River Mersey’s outer estuarial beach during ebb-tide. The injected dye was monitored, sampled and photographed over several tidal cycles. The distinctive features of the plume (full two dimensional cross-sections), sediments and water-table depth were sampled in-situ, close to the injection point (differing from previous contaminant monitoring tests in aquifers). The advective movement is attributed to tidal impact which is different from contaminant transport in aquifers. The experimental results show that plumes have significantly large spatial variability, diverging upwards and converging downwards, with a conical geometric shape which is different from the usual spherical/elliptical shape reported in literature. The mean vertical motion of the plume reaches three times the top-width within ten tidal cycles, exceeding the narrow bottom-width by a factor of order 2. The observed transport features of the plume within the beach sand have significant relevance to saltwater intrusion, surface water and groundwater quality. The field observations are unique and can serve as a valuable benchmark database for relevant numerical studies.China Ministry of Science and Technology 973 program (2014CB745001), Special Program of future development in Shenzhen (201411201645511650) and Shenzhen Key Laboratory for Coastal Ocean Dynamic and Environment(ZDSY20130402163735964)

    Prevalence et facteurs associes a l’halitose buccale : Etude dans une population generale senegalaise

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    Introduction: Halitosis is a common complain among dental patients, chronic among 50% of the adult population, and of oral origin in 90% of the cases. The objective of this study was to evaluate the prevalence and related factors of oral halitosis among a senegalese population. Material and method: This was a transversal descriptive study of 396 Senegalese adults using a 24-point self-assessment questionnaire on halitosis. All subjects were examined to estimate the organoleptic means and to measure the Sulfur Volatile Compounds (SVC), using a halimeter. Halitosis was diagnosed when the level of sulfur volatile Compound was ≥125 ppb and the organoleptic score ≥ 2. Data were statistically analyzed using the chi2 test. Results: The global prevalence of halitosis was 32.3 %. The difference was not statistically significant between male and female. Among the 396 patients suffering from bad breath, 128 had a permanent halitosis and 52 had a physiological halitosis. The means of the organoleptic scores were 3.12 and that of the (SVC) were 273.9 ppb. Conclusion: The results of the study showed a relation between the organoleptic tests and the level of sulfur volatile compounds (SVC). Keywords: Halitosis, organoleptic tests, sulfur volatile compound, epidemiology, and self-assessment

    Using Higher Ionization States to Increase Coulomb Coupling in an Ultracold Neutral Plasma

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    We report measurements and simulations of the time-evolving rms velocity distribution in an ultracold neutral plasma. A strongly coupled ultracold neutral Ca+ plasma is generated by photoionizing laser-cooled atoms close to threshold. A fraction of these ions is then promoted to the second ionization state to form a mixed Ca+-Ca2+ plasma. By varying the time delay between the first and the second ionization events, a minimum in ion heating is achieved. We show that the Coulomb strong-coupling parameter Γ increases by a factor of 1.4 to a maximum value of 3.6. A pure Ca2+ plasma would have Γ=6.8, moving these strongly coupled systems closer to the regime of liquid-like correlations

    How to Estimate the Cost of Point-of-Care CD4 Testing in Program Settings: An Example Using the Alere Pima™ Analyzer in South Africa

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    Integrating POC CD4 testing technologies into HIV counseling and testing (HCT) programs may improve post-HIV testing linkage to care and treatment. As evaluations of these technologies in program settings continue, estimates of the costs of POC CD4 tests to the service provider will be needed and estimates have begun to be reported. Without a consistent and transparent methodology, estimates of the cost per CD4 test using POC technologies are likely to be difficult to compare and may lead to erroneous conclusions about costs and cost-effectiveness. This paper provides a step-by-step approach for estimating the cost per CD4 test from a provider's perspective. As an example, the approach is applied to one specific POC technology, the Pima™ Analyzer. The costing approach is illustrated with data from a mobile HCT program in Gauteng Province of South Africa. For this program, the cost per test in 2010 was estimated at 23.76(materialcosts=23.76 (material costs = 8.70; labor cost per test = 7.33;andequipment,insurance,anddailyqualitycontrol=7.33; and equipment, insurance, and daily quality control = 7.72). Labor and equipment costs can vary widely depending on how the program operates and the number of CD4 tests completed over time. Additional costs not included in the above analysis, for on-going training, supervision, and quality control, are likely to increase further the cost per test. The main contribution of this paper is to outline a methodology for estimating the costs of incorporating POC CD4 testing technologies into an HCT program. The details of the program setting matter significantly for the cost estimate, so that such details should be clearly documented to improve the consistency, transparency, and comparability of cost estimates

    Vietnam-EU Free Trade Agreement: Impact and Policy Implications for Vietnam

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    On 4 August 2015, after three years and several rounds of negotiation, the European Union –Vietnam Free Trade Agreement officially established principles for the basic content of the Agreement. This study aims to analyse impact of Vietnam-EU FTA on bilateral trade of Vietnam. By using a gravity model and a panel data analysis, we show that the reduction of tariffs in the framework of the FTA will have a positive impact on bilateral trade between Vietnam and the EU. In addition, Vietnam-EU FTA will offer many new opportunities but it also challenges for Vietnam. Based on these analyses, this paper proposes some recommendations for Vietnam to benefit more the Vietnam-EU FTA

    Bringing the Nature Futures Framework to life: creating a set of illustrative narratives of nature futures.

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    UNLABELLED: To halt further destruction of the biosphere, most people and societies around the globe need to transform their relationships with nature. The internationally agreed vision under the Convention of Biological Diversity-Living in harmony with nature-is that "By 2050, biodiversity is valued, conserved, restored and wisely used, maintaining ecosystem services, sustaining a healthy planet and delivering benefits essential for all people". In this context, there are a variety of debates between alternative perspectives on how to achieve this vision. Yet, scenarios and models that are able to explore these debates in the context of "living in harmony with nature" have not been widely developed. To address this gap, the Nature Futures Framework has been developed to catalyse the development of new scenarios and models that embrace a plurality of perspectives on desirable futures for nature and people. In this paper, members of the IPBES task force on scenarios and models provide an example of how the Nature Futures Framework can be implemented for the development of illustrative narratives representing a diversity of desirable nature futures: information that can be used to assess and develop scenarios and models whilst acknowledging the underpinning value perspectives on nature. Here, the term illustrative reflects the multiple ways in which desired nature futures can be captured by these narratives. In addition, to explore the interdependence between narratives, and therefore their potential to be translated into scenarios and models, the six narratives developed here were assessed around three areas of the transformative change debate, specifically, (1) land sparing vs. land sharing, (2) Half Earth vs. Whole Earth conservation, and (3) green growth vs. post-growth economic development. The paper concludes with an assessment of how the Nature Futures Framework could be used to assist in developing and articulating transformative pathways towards desirable nature futures. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11625-023-01316-1
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