15 research outputs found

    A Sequential MUSIC algorithm for Scatterers Detection 2 in SAR Tomography Enhanced by a Robust Covariance 3 Estimator

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    Synthetic aperture radar (SAR) tomography (TomoSAR) is an appealing tool for the extraction of height information of urban infrastructures. Due to the widespread applications of the MUSIC algorithm in source localization, it is a suitable solution in TomoSAR when multiple snapshots (looks) are available. While the classical MUSIC algorithm aims to estimate the whole reflectivity profile of scatterers, sequential MUSIC algorithms are suited for the detection of sparse point-like scatterers. In this class of methods, successive cancellation is performed through orthogonal complement projections on the MUSIC power spectrum. In this work, a new sequential MUSIC algorithm named recursive covariance canceled MUSIC (RCC-MUSIC), is proposed. This method brings higher accuracy in comparison with the previous sequential methods at the cost of a negligible increase in computational cost. Furthermore, to improve the performance of RCC-MUSIC, it is combined with the recent method of covariance matrix estimation called correlation subspace. Utilizing the correlation subspace method results in a denoised covariance matrix which in turn, increases the accuracy of subspace-based methods. Several numerical examples are presented to compare the performance of the proposed method with the relevant state-of-the-art methods. As a subspace method, simulation results demonstrate the efficiency of the proposed method in terms of estimation accuracy and computational load

    Mapping geographical inequalities in access to drinking water and sanitation facilities in low-income and middle-income countries, 2000-17

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    Background: Universal access to safe drinking water and sanitation facilities is an essential human right, recognised in the Sustainable Development Goals as crucial for preventing disease and improving human wellbeing. Comprehensive, high-resolution estimates are important to inform progress towards achieving this goal. We aimed to produce high-resolution geospatial estimates of access to drinking water and sanitation facilities. Methods: We used a Bayesian geostatistical model and data from 600 sources across more than 88 low-income and middle-income countries (LMICs) to estimate access to drinking water and sanitation facilities on continuous continent-wide surfaces from 2000 to 2017, and aggregated results to policy-relevant administrative units. We estimated mutually exclusive and collectively exhaustive subcategories of facilities for drinking water (piped water on or off premises, other improved facilities, unimproved, and surface water) and sanitation facilities (septic or sewer sanitation, other improved, unimproved, and open defecation) with use of ordinal regression. We also estimated the number of diarrhoeal deaths in children younger than 5 years attributed to unsafe facilities and estimated deaths that were averted by increased access to safe facilities in 2017, and analysed geographical inequality in access within LMICs. Findings: Across LMICs, access to both piped water and improved water overall increased between 2000 and 2017, with progress varying spatially. For piped water, the safest water facility type, access increased from 40·0% (95% uncertainty interval [UI] 39·4–40·7) to 50·3% (50·0–50·5), but was lowest in sub-Saharan Africa, where access to piped water was mostly concentrated in urban centres. Access to both sewer or septic sanitation and improved sanitation overall also increased across all LMICs during the study period. For sewer or septic sanitation, access was 46·3% (95% UI 46·1–46·5) in 2017, compared with 28·7% (28·5–29·0) in 2000. Although some units improved access to the safest drinking water or sanitation facilities since 2000, a large absolute number of people continued to not have access in several units with high access to such facilities (>80%) in 2017. More than 253 000 people did not have access to sewer or septic sanitation facilities in the city of Harare, Zimbabwe, despite 88·6% (95% UI 87·2–89·7) access overall. Many units were able to transition from the least safe facilities in 2000 to safe facilities by 2017; for units in which populations primarily practised open defecation in 2000, 686 (95% UI 664–711) of the 1830 (1797–1863) units transitioned to the use of improved sanitation. Geographical disparities in access to improved water across units decreased in 76·1% (95% UI 71·6–80·7) of countries from 2000 to 2017, and in 53·9% (50·6–59·6) of countries for access to improved sanitation, but remained evident subnationally in most countries in 2017. Interpretation: Our estimates, combined with geospatial trends in diarrhoeal burden, identify where efforts to increase access to safe drinking water and sanitation facilities are most needed. By highlighting areas with successful approaches or in need of targeted interventions, our estimates can enable precision public health to effectively progress towards universal access to safe water and sanitation

    Megaplasmids encode differing combinations of lantibiotics in Streptococcus salivarius

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    The oral administration of ciprofloxacin (250mg bid) and ofloxacin (300mg bid) in 40 patients with ureteral stents, led to drug levels on all the device surfaces that were higher than the minimum inhibitory concentration (MIC) of Escherichia coli (0.004-0.015 mg/l), the most common uropathogen. The drug levels in the film were higher than the MIC of other common pathogens, namely Pseudomonas aeruginosa (0.25-1.0 mg/l), Enterococcus faecalis (0.25-2.0 mg/l) and Staphylococcus aureus (0.12-0.5 mg/l) in a few cases (six, three and 14 cases out of 40, respectively). For both antibiotics, the concentrations were greater than the MIC of many uropathogens on the film surrounding the devices (0.89 vs 0.31 mg/l respectively, P=0.05), and on the devices themselves (0.22 vs. 0.12 mg/l, P=0.207). Adsorption of the antibiotics was higher to the film than to the stent (P\u3c0.0001). Ciprofloxacin concentration on the film surrounding the stents was significantly higher than that of ofloxacin (P=0.05), while there was no statistical concentration difference between the two antibiotics adsorbed onto the actual devices (P=0.207). No bacteria were found in patients\u27 urine and no biofilms were detected. This is the first report of an oral antibiotic being adsorbed onto medical devices. It potentially provides a new approach of preventing infection, and avoids the need to pre-coat devices with agents whose use will be restricted once bacteria develop resistance to them. If biomaterial properties can be enhanced to increase further the adsorptive concentration of drug, the risk of infections and recalcitrant biofilm formation could be significantly reduced in a highly susceptible patient population. Copyright © 2001 Elsevier Science B.V

    The Effect of Some Herbal Extracts on Nitric Oxide Production in Endothelial Cells 3T3 Cell Line: The Effect of Some Herbal Extracts on Nitric Oxide Production

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    Some studies have demonstrated the potential of herbal drugs for the treatment of various diseases associated with impaired vascular nitric oxide (NO). For diagnosis of the mechanism of these herbal plants, it seems necessary to evaluate the herbal extracts on the Endothelium cell. The aim of the study was to investigate the effect of extract of Trigonella foenum-graecum (T.foenum), Nigella sativa (NS), Allium sativum, and Cannabis sativa on nitric oxide (NO) production by the endothelial cells 3T3 cell line.Ground herbs suspended in water and methanol, were filtered and concentrated under pressure. Remaining contents were dried and obtained powder dissolved in water. The cell line was treated with plant extracts. The clarified supernatant of the culture was used for evaluation of quantitative changes in NO production using Griess test.Among the four extracts, only the group treated with T.foenum extract, significantly increased NO production compared to the control group. Also, NO concentration in other extract group was lower than T.foenum group. This study suggested that the T.foenum extract can significantly increase NO concentration in cell culture and the increase in nitric oxide production is because of the presence of diosgenin T.foenum extracted

    Lipopolysaccharide-induced memory impairment in rats is preventable using 7-nitroindazole

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    Inflammation and oxidative stress have important roles in memory impairment. The effect of 7-nitroindazole (7NI) on lipopolysaccharide (LPS)-induced memory impairment was investigated. Rats were used, divided into four groups that were treated as follows: (1) control (saline); (2) LPS; (3) 7NI-LPS; and (4) 7NI before passive avoidance (PA). In the LPS group, the latency for entering the dark compartment was shorter than in the controls (p < 0.01 and p < 0.001); while in the 7NI-LPS group, it was longer than in the LPS group (p < 0.01 and p < 0.001). Malondialdehyde (MDA) and nitric oxide (NO) metabolite concentrations in the brain tissues of the LPS group were higher than in the controls (p < 0.001 and p < 0.05); while in the 7NI-LPS group, they were lower than in the LPS group (p < 0.001 and p < 0.05, respectively). The thiol content in the brain of the LPS group was lower than in the controls (p < 0.001); while in the 7NI-LPS group, it was higher than in the LPS group (p < 0.001). It is suggested that brain tissue oxidative damage and NO elevation have a role in the deleterious effects of LPS on memory retention that are preventable using 7NI
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