1,174 research outputs found

    Field Application of Spent Lime Water Treatment Residual for the Removal of Phosphorus and other Pollutants in Urban Stormwater Runoff

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    The threat of anthropogenic eutrophication and harmful algal blooms in lakes requires the development of innovative stormwater best management practices (BMPs) to reduce the external loading of phosphorus (P). This paper presents the findings of a 5-year study of a full-scale P removal structure constructed in Minnesota, USA with spent lime drinking water treatment residual (DWTR), a by-product of water softening at a local water treatment plant. Influent and effluent water samples were collected by auto-samplers during 43 storm events during the growing season. Samples were analyzed for P constituents, heavy metals, total suspended solids (TSS), and pH. Toxicity of the effluent was assessed using Ceriodaphnia dubia. Flow-weighted removal effectiveness was calculated for each storm event. Overall, the spent lime DWTR reduced total P loading by 70.9%, dissolved reactive P by 78.5%, dissolved P by 74.7%, and TSS by 58.5%. A significant reduction in heavy metals was also observed. Toxicity tests indicated the aquatic toxicity of the effluent treated with spent lime DWTR was not different from untreated stormwater. This study provided long-term real-world data that demonstrated that a full-scale P removal structure with spent lime DWTR significantly reduced P and other pollutants in stormwater discharging to an urban lake. Therefore, spent lime DWTR, which is currently treated as a waste product, is a promising filter material for stormwater treatment

    Low Dose Coagulant and Local Soil Ballast Effectively Remove Cyanobacteria (Microcystis) from Tropical Lake Water without Cell Damage

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    The combination of a low dose of coagulant with a ballast, also known as "flock and sink," has been proposed as a lake restoration and cyanobacteria bloom management strategy. The effectiveness of this technique using aluminum sulfate (alum) as a coagulant and a local soil (LS) from Thailand as a ballast in eutrophic water dominated by positively buoyant Microcystis colonies collected from a tropical lake was investigated by measuring changes in chlorophyll-a (chl-a), pH, and zeta potential. Cell integrity was also evaluated using scanning electron microscopy. Results showed that alum alone could reduce chl-a (up to 60% to 83%) at doses (higher than 3 to 6 mg Al/L) dependent on the initial pH (7.6 to 8.2) and initial chl-a concentration (138 to 615 mu g/L) of the lake water but resulted in morphological changes to cellular structure and generally required a dose that reduced pH to <7. LS ballast alone was able to reduce chl-a concentrations (up to 26% at highest dose of 400 mg/L) and caused no significant changes to pH or zeta potential. Combining a low dose of alum (2 mg Al/L) with some amount of LS ballast (50 to 400 mg/L) created an interaction effect that resulted in 81 to 88% reduction in chl-a without changes to zeta potential or morphological changes to cellular structure. Flock and sink may serve a niche role in lake restoration when positively buoyant cyanobacteria are present in the water column during time of treatment. This research showed that an 800% increase in ballast dose resulted in about an 8% reduction in chl-a when combined with 2 mg Al/L of alum. Therefore, it is recommended that ballast dose should be determined by considering its phosphorus sorption capacity and the potentially releasable phosphorus in the lake sediment in order to realize long-term reductions in sediment nutrient release

    Washing and Heat Treatment of Aluminum-Based Drinking Water Treatment Residuals to Optimize Phosphorus Sorption and Nitrogen Leaching: Considerations for Lake Restoration

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    Drinking water treatment residuals (DWTRs) generated during drinking water treatment have been proposed for use in lake restoration as a solid-phase sorbent to inactivate phosphorus (P) in lake sediment. However, treatments that minimize leaching of nitrogen (N) and optimize P sorption capacity may be necessary prior to use. This study assessed seven different treatment methods, including washing and heat treatments at different temperatures and with and without oxygen limitation, among two DWTRs from Thailand. Results showed that oxygen-limited heat treatment at 600 degrees C substantially reduced N leaching (<0.2 mg/kg TKN) while also improving P sorption capacity (increase of 18-32% compared to untreated DWTR) to a maximum of 45.7 mg P/kg. Washing with deionized water reduced N leaching if a sufficient volume was used but did not improve P sorption. Heating at 200 degrees C with or without the presence of oxygen did not improve N leaching or P sorption. Regression of P sorption parameters from a two-surface Langmuir isotherm against physio-chemical properties indicated that oxalate-extractable (i.e., amorphous) aluminum and iron were significantly associated with total P sorption capacity (R-2 = 0.94), but micropores and oxalate-extractable P modulated the P sorption from high-affinity to low-affinity mechanisms. In conclusion, this study confirmed the importance of amorphous aluminum in DWTRs for inactivating P, and the results suggest that high-temperature treatment under oxygen-limited conditions may be the most reliable way to optimize DWTRs for environmental remediation applications

    Take That Flood+: Does your perspective matter?

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    How does your viewing perspective matter for decision-making with flood risk maps?*

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    The globally increasing frequency of flood events highlights the importance of effective flood risk communication. The influence of the viewing perspective of mapped flood events on human risk perception has not yet been a research focus of the geovisualization community. This empirical study aims to fill this gap by investigating how the viewing perspective of flood risk maps, that is, 2D orthographic vs. 2.5D oblique views, influence human flood risk perception and decision-making. Results on how viewing perspective might influence measured risk perception are in line with prior inconclusive research on the utility and usability of adding a third viewing dimension on static maps. Unlike prior research would have suggested, we find that the individual risk attitude of our participants had no direct influence on their risk ratings in the context of this study. With additional empirical evidence on how static 2D and oblique 2.5D hazard maps might influence the public’s risk perception and decision-making, we hope to further inform policy and decision makers on the critical importance of well-designed cartographic displays for effective and efficient hazard and risk communication. We also provide an open-source code repository for making reproducible experiments with our static maps

    A newly discovered muscle: The tensor of the vastus intermedius

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    The quadriceps femoris is traditionally described as a muscle group composed of the rectus femoris and the three vasti. However, clinical experience and investigations of anatomical specimens are not consistent with the textbook description. We have found a second tensor-like muscle between the vastus lateralis (VL) and the vastus intermedius (VI), hereafter named the tensor VI (TVI). The aim of this study was to clarify whether this intervening muscle was a variation of the VL or the VI, or a separate head of the extensor apparatus. Twenty-six cadaveric lower limbs were investigated. The architecture of the quadriceps femoris was examined with special attention to innervation and vascularization patterns. All muscle components were traced from origin to insertion and their affiliations were determined. A TVI was found in all dissections. It was supplied by independent muscular and vascular branches of the femoral nerve and lateral circumflex femoral artery. Further distally, the TVI combined with an aponeurosis merging separately into the quadriceps tendon and inserting on the medial aspect of the patella. Four morphological types of TVI were distinguished: Independent-type (11/26), VI-type (6/26), VL-type (5/26), and Common-type (4/26). This study demonstrated that the quadriceps femoris is architecturally different from previous descriptions: there is an additional muscle belly between the VI and VL, which cannot be clearly assigned to the former or the latter. Distal exposure shows that this muscle belly becomes its own aponeurosis, which continues distally as part of the quadriceps tendon

    Early results in the treatment of proximal humeral fractures with a polyaxial locking plate

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    Objectives: We report early results using a second generation locking plate, non-contact bridging plate (NCB PH®, Zimmer Inc. Warsaw, IN, USA), for the treatment of proximal humeral fractures. The NCB PH® combines conventional plating technique with polyaxial screw placement and angular stability. Design: Prospective case series. Setting: A single level-1 trauma center. Patients: A total of 50 patients with proximal humeral fractures were treated from May 2004 to December 2005. Intervention: Surgery was performed in open technique in all cases. Main outcome measures: Implant-related complications, clinical parameters (duration of surgery, range of motion, Constant-Murley Score, subjective patient satisfaction, complications) and radiographic evaluation [union, implant loosening, implant-related complications and avascular necrosis (AVN) of the humeral head] at 6, 12 and 24weeks. Results: All fractures available to follow-up (48 of 50) went to union within the follow-up period of 6months. One patient was lost to follow-up, one patient died of a cause unrelated to the trauma, four patients developed AVN with cutout, one patient had implant loosening, three patients experienced cutout and one patient had an axillary nerve lesion (onset unknown). The average age- and gender-related Constant Score (n=35) was 76. Conclusions: The NCB PH® combines conventional plating technique with polyaxial screw placement and angular stability. Although the complication rate was 19%, with a reoperation rate of 12%, the early results show that the NCB PH® is a safe implant for the treatment of proximal humeral fracture

    Socio-culture and Health Problem Factors on Traditional Medicine Use among Indonesian Adult: A Cross-sectional Analysis from National Survey

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    Traditional medicines utilization has been significantly increased over the past years. Knowledge on traditional medicine use and its influencing socio-culture and health problem factors especially among generationally-related group in Indonesia is still limited. This study aimed to determine the prevalence and the association socio-culture and health problems factors and traditional medicine use among adults which were middle-aged (millennial) and elder-adult (generation X) in Indonesia while controlling other covariates. of traditional medicine use among This cross-sectional study used the data from the Indonesia Family Life Survey wave 5 (2014): a cross-sectional national population survey. This national survey used a multistage stratified random sampling to select the respondents to response to a structured questionnaire interview. There were 10,325 adults passed our inclusion criteria for the analysis. The adult who was born between1960 to 1982 was called the Gen X, whereas the Millennia is for those who were born between 1983 and 2000. A multivariable logistic regression was used to identify the association. Among 10,325 respondents, 78.42 % were millennial while 21.58 % were generation x or older adults. &nbsp;Less than a quarter of the respondents used traditional medicine (13.37 %; 95% CI: 12.73-14.04). The factor significantly associated with traditional medicine used among Indonesian adults were; be Gen X (adj. OR = 1.24, 95%CI= 1.08 -1.43), female (adj.OR1.27, 95%CI: 1.13 to 1.43, p&lt;0.001) Islamic (adj. OR = 1.91, 95%CI= 1.47 -2.36), married (adj. OR = 1.64, 95%CI= 1.44 -1.87),lived in urban area (adj. OR = 1.48, 95%CI= 1.31-1.68). Other covariate were unhealthy (adj.OR: 1.36, 95% CI: 1.18-1.1.58), experienced headache (adj.OR: 1.50, 95% CI: 1.31-1.47),&nbsp; experienced stomachache (adj.OR: 1.28, 95% CI: 1.12-.47), and experienced fever (adj.OR: 1.30, 95% CI: 1.15- 1.47). Sociocultural and age group as well as health problems were associated with traditional medicine use

    Disseminated Microsporidiosis Due to Encephalitozoon hellem: Pulmonary Colonization, Microhematuria, and Mild Conjunctivitis in a Patient with AIDS

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    Four genera of microsporidia have been associated with disease in humans, which predominantly affects immunocompromised persons. Systemic infection with a newly characterized microsporidian species, Encephalitozoon hellem, was recently reported in a patient with AIDS. This article describes a second patient with AIDS and disseminated E. hellem infection. In this case the parasite was detected in sputum, urine, and conjunctival swab specimens. Apart from recurrent mild conjunctivitis and asymptomatic microhematuria, the patient had no findings or symptoms that could be related to this parasite. Specifically, no microsporidian-associated pulmonary pathology was documented. Detection of E. hellem in the patient's sputum may have epidemiological implications in that this finding suggests transmission of microsporidia by the aerosol route. Because the patient died of unrelated complications, it remains unknown whether he was an asymptomatic carrier of microsporidia or whether microhematuria heralded early microsporidian disease, with the onset of cellular damage in the urinary trac
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