409 research outputs found

    Empirical wind model for the middle and lower atmosphere. Part 1: Local time average

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    The HWM90 thermospheric wind model was revised in the lower thermosphere and extended into the mesosphere and lower atmosphere to provide a single analytic model for calculating zonal and meridional wind profiles representative of the climatological average for various geophysical conditions. Gradient winds from CIRA-86 plus rocket soundings, incoherent scatter radar, MF radar, and meteor radar provide the data base and are supplemented by previous data driven model summaries. Low-order spherical harmonics and Fourier series are used to describe the major variations throughout the atmosphere including latitude, annual, semiannual, and longitude (stationary wave 1). The model represents a smoothed compromise between the data sources. Although agreement between various data sources is generally good, some systematic differences are noted, particularly near the mesopause. Root mean square differences between data and model are on the order of 15 m/s in the mesosphere and 10 m/s in the stratosphere for zonal wind, and 10 m/s and 4 m/s, respectively, for meridional wind

    Preliminary estimates of radiosonde thermistor errors

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    Radiosonde temperature measurements are subject to errors, not the least of which is the effect of long- and short-wave radiation. Methods of adjusting the daytime temperatures to a nighttime equivalent are used by some analysis centers. Other than providing consistent observations for analysis this procedure does not provide a true correction. The literature discusses the problem of radiosonde temperature errors but it is not apparent what effort, if any, has been taken to quantify these errors. To accomplish the latter, radiosondes containing multiple thermistors with different coatings were flown at Goddard Space Flight Center/Wallops Flight Facility. The coatings employed had different spectral characteristics and, therefore, different adsorption and emissivity properties. Discrimination of the recorded temperatures enabled day and night correction values to be determined for the US standard white-coated rod thermistor. The correction magnitudes are given and a comparison of US measured temperatures before and after correction are compared with temperatures measured with the Vaisala radiosonde. The corrections are in the proper direction, day and night, and reduce day-night temperature differences to less than 0.5 C between surface and 30 hPa. The present uncorrected temperatures used with the Viz radiosonde have day-night differences that exceed 1 C at levels below 90 hPa. Additional measurements are planned to confirm these preliminary results and determine the solar elevation angle effect on the corrections. The technique used to obtain the corrections may also be used to recover a true absolute value and might be considered a valuable contribution to the meteorological community for use as a reference instrument

    Endodontic drug delivery for root surface disinfection: a laboratory feasibility evaluation

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    OBJECTIVES This study aims to assess the potential of a mixture of three antibiotics (TreVitaMix, TVM) as an intracanal dressing to disinfect the outer root surface by applying a new in vitro model. MATERIALS AND METHODS Fifty freshly extracted bovine roots were endodontically treated. Forty samples were then thoroughly scaled, mounted to petri dishes, gas sterilized, and randomly allocated to four groups (n = 10/group) according to their intracanal medication: sterile saline (NaCl; control, A); the TVM carrier material alone, i.e., propylene glycol (PG; B); TVM (C); and calcium hydroxide (D). In an additional group (E), the cementum was not removed and TVM was placed. Petri dishes were filled with Fastidious Anaerobe Agar, inoculated with Fusobacterium nucleatum suspension and then anaerobically incubated during 48-h intervals at 37 °C up to 192 h. Inhibition zones around the roots were then measured after each incubation period (mm(2)). RESULTS Only teeth inoculated with the TVM dressing showed inhibition at all time points, whereas the other treatments showed no peri-radicular growing inhibition. Presence of cementum had no negative effect on disinfection (p = 0.9320). CONCLUSION TVM was able to penetrate through the dentine and inhibit the bacterial growth of F. nucleatum up to 192 h. CLINICAL RELEVANCE TVM might have the potential to sustainably disinfect the outer root surface in perio-endo lesions and serve as an adjunctive antimicrobial agent

    Effect of titanium tetrafluoride and amine fluoride treatment combined with carbon dioxide laser irradiation on enamel and dentin erosion

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    OBJECTIVE: This in vitro study aimed to analyze the influence of carbon dioxide (CO(2)) laser irradiation on the efficacy of titanium tetrafluoride (TiF(4)) and amine fluoride (AmF) in protecting enamel and dentin against erosion. METHODS: Bovine enamel and dentin samples were pretreated with carbon dioxide (CO(2)) laser irradiation only (group I), TiF(4) only (1% F, group II), CO(2) laser irradiation before (group III) or through (group IV) TiF(4) application, AmF only (1% F, group V), or CO(2) laser irradiation before (group VI) or through (group VII) AmF application. Controls remained untreated. Ten samples of each group were then subjected to an erosive demineralization and remineralization cycling for 5 days. Enamel and dentin loss were measured profilometrically after pretreatment, 4 cycles (1 day), and 20 cycles (5 days) and statistically analyzed using analysis of variance and Scheffe's post hoc tests. Scanning electron microscopy (SEM) analysis was performed in pretreated but not cycled samples (two samples each group). RESULTS: After 20 cycles, there was significantly less enamel loss in groups V and IV and significantly less dentin loss in group V only. All other groups were not significantly different from the controls. Lased surfaces (group I) appeared unchanged in the SEM images, although SEM images of enamel but not of dentin showed that CO(2) laser irradiation affected the formation of fluoride precipitates. CONCLUSION: AmF decreased enamel and dentin erosion, but CO(2) laser irradiation did not improve its efficacy. TiF(4) showed only a limited capacity to prevent erosion, but CO(2) laser irradiation significantly enhanced its ability to reduce enamel erosion

    Identifying risk factors for Plasmodium infection and anaemia in Kinshasa, Democratic Republic of Congo

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    There is little data on the risk factors for malaria infection in large cities in central Africa and in all age groups. There may be different associations with the risk factors for areas with different malaria transmission intensities such as the effect of fever or age. This study aimed at identifying risk factors associated with Plasmodium infection and anaemia among children 6-59 months and individuals aged older than 5 years in Kinshasa, a large city with heterogeneity in malaria prevalence.; This study analysed data from 3342 children aged 6-59 months from 25 non-rural health zones (HZs) and for 816 individuals aged older than 5 years from two HZs in Kinshasa (non-rural), collected during a cross sectional malaria survey in 2011. Logistic regression with random effects was used to investigate predictors for malaria and anaemia. Differences in risk factors in areas with a prevalence of less than 10 and 10 % or greater were investigated.; There was evidence of a different age-pattern in the two transmission settings. For children under 5 years, the highest prevalence of malaria was observed in the 48-59 months group in both transmission settings, but it increased more gently for the lower transmission HZs (p = 0.009). In a separate analysis in children over 5 years in two selected HZs, the peak prevalence was in 5-9 years old in the higher transmission setting and in 15-19 years old in the lower transmission setting. Reported fever was associated with malaria in both transmission strata, with no evidence of a difference in these associations (p = 0.71); however in children older than 5 years there was a significant interaction with a stronger association in the low transmission HZ. Insecticide-treated net (ITN) use was associated with a lower risk of malaria infection in children 6-59 months in the high transmission HZs. Similar estimates were found in children over 5 years and the lower transmission HZ but the associations there were not significant. There was no evidence of a difference in these associations by strata. The risk of anaemia decreased with increasing age in all strata, whereas it increased with malaria infection and reported fever. ITN use did not show evidence of protection against anaemia. Low socio-economic status was associated with malaria in high transmission setting in children 6-59 months and anaemia in low transmission setting.; This study shows that in areas of low transmission in Kinshasa, the peak prevalence occurs in older age groups however ITN use was highest in children under 5 years. Targeted distribution of ITN to all age groups should be continued. For most risk factors, there was no evidence of an interaction with transmission intensity however the associations with age and with fever in the last 2 weeks did vary significantly

    Association of 1,5-Anhydroglucitol and 2-h Postprandial Blood Glucose in Type 2 Diabetic Patients

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    OBJECTIVE—To assess the association of 1,5-anhydroglucitol (1,5-AG) with 2-h postprandial glucose values in type 2 diabetic patients followed over 12 months in an outpatient setting

    Geographical variation in the carbon, nitrogen, and phosphorus content of blue mussels, Mytilus edulis

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    Shellfish farming contributes to nutrient removal in coastal and estuarine systems, as bivalves incorporate nutrients into their tissues and shells, which is removed from the marine system on harvest. Fourteen locations around the UK were surveyed to explore geographic variation in carbon, nitrogen and phosphorus content of tissue and shell in blue mussels. Phosphorus in tissue had a significant negative relationship with mean annual seawater temperature for both rope and bottom cultured sites. Per tonne of live mussel, rope culture removed significantly more nitrogen (8.50 ± 0.59 kg) and phosphorus (0.95 ± 0.07 kg) than bottom cultured (5.00 ± 0.013 kg nitrogen and 0.43 ± 0.01 kg phosphorus). Bottom culture, however, provides significantly more C removal in shell (60.15 ± 0.77 kg) than in rope cultured (46.12 ± 1.69 kg). Further studies are required to examine the effect of growth rate, on the nitrogen and phosphorus remediation, and carbon stored in shell, of rope culture and bottom cultured mussel aquaculture

    Propagation of short-period gravity waves at high-latitudes during the MaCWAVE winter campaign

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    As part of the MaCWAVE (Mountain and Convective Waves Ascending Vertically) winter campaign an all-sky monochromatic CCD imager has been used to investigate the properties of short-period mesospheric gravity waves at high northern latitudes. Sequential measurements of several nightglow emissions were made from Esrange, Sweden, during a limited period from 27–31 January 2003. Coincident wind measurements over the altitude range (~80–100 km) using two meteor radar systems located at Esrange and Andenes have been used to perform a novel investigation of the intrinsic properties of five distinct wave events observed during this period. Additional lidar and MSIS model temperature data have been used to investigate their nature (i.e. freely propagating or ducted). Four of these extensive wave events were found to be freely propagating with potential source regions to the north of Scandinavia. No evidence was found for strong orographic forcing by short-period waves in the airglow emission layers. The fifth event was most unusual exhibiting an extensive, but much smaller and variable wavelength pattern that appeared to be embedded in the background wind field. Coincident wind measurements indicated the presence of a strong shear suggesting this event was probably due to a large-scale Kelvin-Helmholtz instability

    Efficacy and safety of intravenous ferric carboxymaltose compared with oral iron for the treatment of iron deficiency anaemia in women after childbirth in Tanzania: a parallelgroup, open-label, randomised controlled phase 3 trial

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    Background: Iron deficiency anaemia is of major concern in low-income settings, especially for women of childbearing age. Oral iron substitution efficacy is limited by poor compliance and iron depletion severity. We aimed to assess the efficacy and safety of intravenous ferric carboxymaltose versus oral iron substitution following childbirth in women with iron deficiency anaemia in Tanzania. Methods: This parallel-group, open-label, randomised controlled phase 3 trial was done at Bagamoyo District Hospital and Mwananyamala Hospital, Tanzania. Eligible participants were close to delivery and had iron deficiency anaemia defined as a haemoglobin concentration of less than 110 g/L and a ferritin concentration of less than 50 μg/L measured within 14 days before childbirth. Participants were randomly assigned 1:1 to receive intravenous ferric carboxymaltose or oral iron, stratified by haemoglobin concentration and site. Intravenous ferric carboxymaltose was administered at a dose determined by the haemoglobin concentration and bodyweight (bodyweight 35 kg to <70 kg and haemoglobin ≥100 g/L: 1000 mg in one dose; bodyweight 35 kg to <70 kg and haemoglobin <100 g/L, or bodyweight ≥70 kg and haemoglobin ≥100 g/L: 1500 mg in two doses at least 7 days apart; bodyweight ≥70 kg and haemoglobin 115 g/L) at 6 weeks. Follow-up visits were at 6 weeks, and 3, 6, and 12 months. Analyses were done in the modified intention-totreat population of participants who had a 6-week haemoglobin concentration result, using logistic and linear regression models for binary and continuous outcomes, adjusted for baseline haemoglobin concentration and site. This trial is registered with ClinicalTrials.gov, NCT02541708. Findings: Between Oct 8, 2015, and March 14, 2017, 533 individuals were screened and 230 were enrolled and randomly assigned to a study group (114 to intravenous iron, 116 to oral iron). At 6 weeks, 94 (82%) participants in the intravenous iron group and 92 (79%) in the oral iron group were assessed for the primary outcome. 75 (80%) participants in the intravenous iron group and 47 (51%) in the oral iron group had normalised haemoglobin (odds ratio 4·65, 95% CI 2·33-9·27). There were two mild to moderate infusion-related adverse events; and five serious adverse events (three in the intravenous iron group, two in the oral iron group), unrelated to the study medication. Interpretation: Intravenous iron substitution with ferric carboxymaltose was safe and yielded a better haemoglobin response than oral iron. To our knowledge, this is the first study to provide evidence of the benefits and safety of intravenous iron substitution in a low-income setting
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