662 research outputs found

    Lidar as a Shoreline Mapping Tool

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    Using Moored Arrays and Hyperspectral Aerial Imagery to Develop Nutrient Criteria for New Hampshire\u27s Estuaries

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    Increasing nitrogen concentrations and declining eelgrass beds in Great Bay, NH are clear indicators of impending problems for the state’s estuaries. A workgroup established in 2005 by the NH Department of Environmental Services and the NH Estuaries Project (NHEP) adopted eelgrass survival as the water quality target for nutrient criteria development for NH’s estuaries. In 2007, the NHEP received a grant from the U.S. Environmental Protection Agency to collect water quality information including that from moored sensors and hyper-spectral imagery data of the Great Bay Estuary. Data from the Great Bay Coastal Buoy, part of the regional Integrated Ocean Observing System (IOOS), were used to derive a multivariate model of water clarity with phytoplankton, Colored Dissolved Organic Matter (CDOM), and non-algal particles. Non-algal particles include both inorganic and organic matter. Most of the temporal variability in the diffuse attenuation coefficient of Photosynthetically Available Radiation (PAR) was associated with non-algal particles. However, on a mean daily basis non-algal particles and CDOM contributed a similar fraction (~30 %) to the attenuation of light. The contribution of phytoplankton was about a third of the other two optically important constituents. CDOM concentrations varied with salinity and magnitude of riverine inputs demonstrating its terrestrial origin. Non-algal particle concentration also varied with river flow but also wind driven resuspension. Twelve of the NHEP estuarine assessment zones were observed with the hyperspectral aerial imagery on August 29 and October 17. A concurrent in situ effort included buoy measurements, continuous along-track sampling, discrete water grab samples, and vertical profiles of light attenuation. PAR effective attenuation coefficients retrieved from deep water regions in the imagery agreed well with in-situ observations. Water clarity was lower and optically important constituent concentrations were higher in the tributaries. Eelgrass survival depth, estimated as the depth at which 22% of surface light was available, ranged from less than half a meter to over two meters. The best water clarity was found in the Great Bay (GB), Little Bay (LB), and Lower Piscataqua River (LPR) assessment zones. Absence of eelgrass from these zones would indicate controlling factors other than water clarity

    Lymphatic Filariasis Control in Tanzania: Effect of Six Rounds of Mass Drug Administration with Ivermectin and Albendazole on Infection and Transmission.

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    Control of lymphatic filariasis (LF) in most countries of sub-Saharan Africa is based on annual mass drug administration (MDA) with a combination of ivermectin and albendazole, in order to interrupt transmission. We present findings from a detailed study on the effect of six rounds of MDA with this drug combination as implemented by the National Lymphatic Filariasis Elimination Programme (NLFEP) in a highly endemic rural area of north-eastern Tanzania.\ud The effect of treatment on transmission and human infection was monitored in a community- and a school-based study during an 8-year period (one pre-intervention and 7 post-intervention years) from 2003 to 2011. Before intervention, 24.5% of the community population had microfilariae (mf) in the blood, 53.3% had circulating filarial antigens (CFA) and 78.9% had specific antibodies to the recombinant filarial antigen Bm14. One year after the sixth MDA, these values had decreased considerably to 2.7%, 19.6% and 27.5%, respectively. During the same period, the CFA prevalence among new intakes of Standard 1 pupils in 10 primary schools decreased from 25.2% to 5.6%. In line with this, transmission by the three vectors (Anopheles gambiae, An. funestus and Culex quinquefasciatus) as determined by dissection declined sharply (overall vector infectivity rate by 99.3% and mean monthly transmission potential by 99.2% between pre-intervention and fifth post-intervention period). A major shift in vector species composition, from predominantly anopheline to almost exclusively culicine was observed over the years. This may be largely unrelated to the MDAs but may have important implications for the epidemiology of LF in the area. Six MDAs caused considerable decrease in all the measured indices for transmission and human infection. In spite of this, indices were still relatively high in the late period of the study, and it may take a long time to reach the recommended cut-off levels for interruption of transmission unless extra efforts are made. These should include increased engagement of the target population in the control activities, to ensure higher treatment coverage. It is expected that the recent initiative to distribute insecticide impregnated bed nets to every household in the area will also contribute towards reaching the goal of successful LF elimination

    Effect of sildenafil citrate on the body weight, blood glucose and white blood cell count during wound healing process in diabetic rats

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    Diabetes mellitus is a chronic metabolic disorder with major complication of delayed wound healing. Objectives: The purpose of this study was to evaluate the effect of sildenafil on blood glucose level, body weight and leucocytecount during wound healing in diabetic rats. Method: Forty-two Albino rats randomly divided into 7 groups of 6 rats per group were treatedorally with sildenafil (50 mg/kg) for 21 days and/or single dose of intraperitoneal injection of insulin (10 I.U.). Before treatments, diabetes was induced in groups A, B, C and D by a singleintraperitoneal injection of alloxan (130mg/kg) and a square-shaped wound measuring 1.5cm was created under anesthesia on the dorsum of rats in all groups except group G. The rats ingroup A were treated with sildenafil citrate orally at the dose rate of 50 mg/kg body weight for 21 days and the rats in group B were treated with insulin injection of 10 international units once and sildenafil citrate as in Group A. The rats in group C were treated with only insulin injection of 10 international units once and the rats in group D were treated with only distilled water. Groups E and F were non diabetic rats with wounds similar to those of diabetic rats in the previous groups and each rat in group E was also treated with sildenafil citrate as in Group A and those in group F were treated with only distilled water. The rats in Group G were normal rats without wound treated with sildenafil citrate as in Group A. Data collected were analysed using SPSS version 20. Results: The results indicated that sildenafil causes a non significant (P>0.05) decrease in the blood glucose of diabetic rats, a significant (P<0.05) increase in the leucocyte count and a significant decrease(p<0.05) in the rate of percentage decrease in bodyweight. Conclusion: Sildenafil may have the potential of reducing the rate of body weight loss in diabetic rats (with or without wound) receiving insulin treatment

    Risk Factors for Cervical Precancer and Cancer in HIV-Infected, HPV-Positive Rwandan Women

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    Although cervical cancer is an AIDS-defining condition, infection with human immunodeficiency virus (HIV) may only modestly increase the risk of cervical cancer. There is a paucity of information regarding factors that influence the natural history of human papillomavirus (HPV) in HIV-infected women. We examined factors associated with cervical intraepithelial neoplasia grade 3 or cancer (CIN3+) in Rwandan women infected with both HIV and HPV (HIV+/HPV+).In 2005, 710 HIV+ Rwandan women ≥25 years enrolled in an observational cohort study; 476 (67%) tested HPV+. Each woman provided sociodemographic data, CD4 count, a cervical cytology specimen and cervicovaginal lavage (CVL), which was tested for >40 HPV genotypes by MY09/MY11 PCR assay. Logistic regression models calculated odds ratios (OR) and 95% confidence intervals (CI) of associations of potential risk factors for CIN3+ among HIV+/HPV+ women.Of the 476 HIV+/HPV+ women 42 (8.8%) were diagnosed with CIN3+. Factors associated with CIN3+ included ≥7 (vs. 0-2) pregnancies, malarial infection in the previous six months (vs. never), and ≥7 (vs. 0-2) lifetime sexual partners. Compared to women infected by non-HPV16 carcinogenic HPV genotypes, HPV16 infection was positively associated and non-carcinogenic HPV infection was inversely associated with CIN3+. CD4 count was significantly associated with CIN3+ only in analyses of women with non-HPV16 carcinogenic HPV (OR = 0.62 per 100 cells/mm(3), CI = 0.40-0.97).In this HIV+/HPV+ population, lower CD4 was significantly associated with CIN3+ only in women infected with carcinogenic non-HPV16. We found a trend for higher risk of CIN3+ in HIV+ women reporting recent malarial infection; this association should be investigated in a larger group of HIV+/HPV+ women

    Surfactant status and respiratory outcome in premature infants receiving late surfactant treatment.

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    BACKGROUND:Many premature infants with respiratory failure are deficient in surfactant, but the relationship to occurrence of bronchopulmonary dysplasia (BPD) is uncertain. METHODS:Tracheal aspirates were collected from 209 treated and control infants enrolled at 7-14 days in the Trial of Late Surfactant. The content of phospholipid, surfactant protein B, and total protein were determined in large aggregate (active) surfactant. RESULTS:At 24 h, surfactant treatment transiently increased surfactant protein B content (70%, p < 0.01), but did not affect recovered airway surfactant or total protein/phospholipid. The level of recovered surfactant during dosing was directly associated with content of surfactant protein B (r = 0.50, p < 0.00001) and inversely related to total protein (r = 0.39, p < 0.0001). For all infants, occurrence of BPD was associated with lower levels of recovered large aggregate surfactant, higher protein content, and lower SP-B levels. Tracheal aspirates with lower amounts of recovered surfactant had an increased proportion of small vesicle (inactive) surfactant. CONCLUSIONS:We conclude that many intubated premature infants are deficient in active surfactant, in part due to increased intra-alveolar metabolism, low SP-B content, and protein inhibition, and that the severity of this deficit is predictive of BPD. Late surfactant treatment at the frequency used did not provide a sustained increase in airway surfactant

    Comparison of four different treatment strategies in teeth with molar-incisor hypomineralization-related enamel breakdown–A retrospective cohort study

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    Background There is little information available on the longevity of non-invasive glass ionomer cement (GIC) and composite restorations as well as conventional composite and ceramic restorations placed on permanent teeth with enamel breakdowns due to molar-incisor hypomineralization (MIH). Aim To compare the longevity of the abovementioned treatment procedures. Design Of 377 identified MIH patients, 118 individuals received restorative treatment and were invited for clinical examination, including caries and MIH status. Finally, survival data from 204 MIH-related restorations placed on 127 teeth were retrospectively collected from 52 children, monitored between 2010 and 2018. Descriptive and explorative analyses were performed, including Kaplan-Meier estimators and the Cox regression model. Results The mean patient observation time was 42.9 months (SD = 35.1). The cumulative survival probabilities after 36 months—7.0% (GIC, N = 28), 29.9% (non-invasive composite restoration, N = 126), 76.2% (conventional composite restoration, N = 27) and 100.0% (ceramic restoration, N = 23)—differed significantly in the regression analysis. Conclusions Conventional restorations were associated with moderate-to-high survival rates in MIH teeth. In contrast, non-invasive composite restorations, which were predominately used in younger or less cooperative children, were linked to lower survival rates

    Methicillin sensitive Staphylococcus aureus producing Panton-Valentine leukocidin toxin in Trinidad & Tobago: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Certain <it>Staphylococcus aureus </it>strains produce Panton-Valentine leukocidin, a toxin that lyses white blood cells causing extensive tissue necrosis and chronic, recurrent or severe infection. This report documents a confirmed case of methicillin-sensitive <it>Staphylococcus aureus </it>strain harboring Panton-Valentine leukocidin genes from Trinidad and Tobago. To the best of our knowledge, this is the first time that such a case has been identified and reported from this country.</p> <p>Case presentation</p> <p>A 13-year-old Trinidadian boy of African descent presented with upper respiratory symptoms and gastroenteritis-like syptoms. About two weeks later he was re-admitted to our hospital complaining of pain and weakness affecting his left leg, where he had received an intramuscular injection of an anti-emetic drug. He deteriorated and developed septic arthritis, necrotizing fasciitis and septic shock with acute respiratory distress syndrome, leading to death within 48 hours of admission despite intensive care treatment. The infection was caused by <it>S. aureus</it>. Bacterial isolates from specimens recovered from our patient before and after his death were analyzed using microarray DNA analysis and <it>spa </it>typing, and the results revealed that the <it>S. aureus </it>isolates belonged to clonal complex 8, were methicillin-susceptible and positive for Panton-Valentine leukocidin. An autopsy revealed multi-organ failure and histological tissue stains of several organs were also performed and showed involvement of his lungs, liver, kidneys and thymus, which showed Hassal's corpuscles.</p> <p>Conclusion</p> <p>Rapid identification of Panton-Valentine leukocidin in methicillin-sensitive <it>S. aureus </it>isolates causing severe infections is necessary so as not to miss their potentially devastating consequences. Early feedback from the clinical laboratories is crucial.</p

    Metabolic analysis of the interaction between plants and herbivores

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    Insect herbivores by necessity have to deal with a large arsenal of plant defence metabolites. The levels of defence compounds may be increased by insect damage. These induced plant responses may also affect the metabolism and performance of successive insect herbivores. As the chemical nature of induced responses is largely unknown, global metabolomic analyses are a valuable tool to gain more insight into the metabolites possibly involved in such interactions. This study analyzed the interaction between feral cabbage (Brassica oleracea) and small cabbage white caterpillars (Pieris rapae) and how previous attacks to the plant affect the caterpillar metabolism. Because plants may be induced by shoot and root herbivory, we compared shoot and root induction by treating the plants on either plant part with jasmonic acid. Extracts of the plants and the caterpillars were chemically analysed using Ultra Performance Liquid Chromatography/Time of Flight Mass Spectrometry (UPLCT/MS). The study revealed that the levels of three structurally related coumaroylquinic acids were elevated in plants treated on the shoot. The levels of these compounds in plants and caterpillars were highly correlated: these compounds were defined as the ‘metabolic interface’. The role of these metabolites could only be discovered using simultaneous analysis of the plant and caterpillar metabolomes. We conclude that a metabolomics approach is useful in discovering unexpected bioactive compounds involved in ecological interactions between plants and their herbivores and higher trophic levels.
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