851 research outputs found

    Density measurements using coherence imaging spectroscopy based on Stark broadening

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    A coherence imaging camera has been set up at Pilot-PSI. The system is to be used for imaging the plasma density through the Stark effect broadening of the H(γ) line. Local density values are then obtained by the Abel inversion of the measured interferometric fringe contrast. This report will present the instrument setup and proof-of-principle demonstration. The inverted spatial electron density profiles obtained near the cascaded arc source of Pilot-PSI in discharges with axial magnetic field of B=0.4 T are compared with an independent measurement of electron density by Thomson scattering and good agreement is found.This work, supported by the European Communities under the contract of the Association EURATOM/FOM, was carried out within the framework of the European Fusion Programme with financial support from NWO

    Erosion yields of carbon under various plasma conditions in Pilot-PSI

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    Fine-grain graphite targets have been exposed to ITER divertor relevant plasmas in Pilot-PSI to address material migration issues in fusion devices. Optical emission spectroscopy and mass loss measurements have been employed to quantify gross chemical erosion and net erosion yields, respectively. Effects of the ion impact energy and target geometry on carbon erosion yields have been studied. It is concluded that temporal evolution of gross chemical erosion is strongly connected with changes in morphology of plasma exposed surfaces. The net carbon erosion yield is increased when the targets are partly covered by insulating boron-nitride rings.Comment: 14 pages, 4 figures, Contribution to the 19th International Conference on Plasma Surface Interaction

    Intimate partner violence in early adolescence : the role of gender, socio-economic factors and the school

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    Background: Intimate partner violence (IPV) among adolescents is common worldwide, but our understanding of perpetration, gender differences and the role of social-ecological factors remains limited. Objectives: To explore the prevalence of physical and sexual IPV perpetration and victimisation by gender, and associated risk and protective factors. Methods: Young adolescents (N=2 839) from 41 randomly selected public high schools in the Western Cape region of South Africa (SA), participating in the PREPARE study, completed a self-administered questionnaire. Results: The participants’ mean age was 13.65 years (standard deviation 1.01), with 19.1% (541/2 839) reporting being victims/survivors of IPV and 13.0% (370/2 839) reporting perpetrating IPV. Girls were less likely to report being a victim/survivor of physical IPV (odds ratio (OR) 0.72; 95% confidence interval (CI) 0.57 - 0.92) and less likely to be a perpetrator of sexual IPV than boys (OR 0.33; 95% CI 0.21 - 0.52). Factors associated with perpetration of physical and sexual IPV were similar and included being a victim/survivor (physical IPV: OR 12.42; 95% CI 8.89 - 17.36, sexual IPV: OR 20.76; 95% CI 11.67 - 36.93), being older (physical IPV: OR 1.26; 95% CI 1.08 - 1.47, sexual IPV: OR 1.36; 95% CI 1.14 - 1.62 ), having lower scores on school connectedness (physical IPV: OR 0.59; 95% CI 0.46 - 0.75, sexual IPV: OR 0.56; 95% CI 0.42 - 0.76) and scoring lower on feelings of school safety (physical IPV: OR 0.66; 95% CI 0.57 - 0.77, sexual IPV: OR 0.50; 95% CI 0.40 - 0.62). Conclusions: Physical and sexual IPV was commonly reported among young adolescents in SA. Further qualitative exploration of the role of reciprocal violence by gender is needed, and the role of ‘school climate’-related factors should be taken into account when developing preventive interventions

    Tuning the tide: creating ecological conditions for tidal marsh development in a flood control area

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    The Schelde estuary, characterised as a turbid, polluted and eutrophic system, has nowadays reached a turning point in the restoration of its water quality. During the past century, human activities have reduced the intertidal areas, essential in the estuarine ecosystem for nutrient cycling and the self-cleaning capacity. Today, in combination with a master plan to protect the population from storm surges, an opportunity rises to restore areas with a tidal influence. One specific option of combining safety and ecology is the creation of flood control areas (FCA) under the influence of a controlled reduced tide (CRT). These specific areas will differ in many ways from fully tidal areas. However, these areas can fulfill important ecological functions with effects on aeration, nitrification, denitrification, sedimentation and primary production in the estuary. Opportunities for ecological development within a CRT have been investigated for a specific case. The ecology within a CRT showed to be very case specific, depending e.g. on the morphology of the area, the sluice design and the local water quality. Depending on the sluice design, water quality can be improved and sedimentation can be influenced. Possible measures to design a CRT with a rich habitat variation are discussed

    Prevalence of sexually transmitted infections in women attending antenatal care in Tete province, Mozambique

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    Objective. To determine the prevalence of Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG) and syphilis in pregnant women. Methods. A cross-sectional study was conducted among women attending antenatal care clinics (ANCs). Blood samples were tested for syphilis using the rapid plasma reagin (RPR) and treponemal haemagglutination (TPHA) tests; CT and NG were diagnosed using a manual polymerase chain reaction assay on first-void urine samples. A socio-demographic questionnaire was completed. Results were compared with previous published data on sexually transmitted infection (STI) prevalence in Mozambique. Results. Blood and urine samples were collected from 1 119 and 835 women, respectively. The prevalence of CT was 4.1%, and that of NG 2.5%. The RPR test was positive in 5.2% of the women, and 7.1% had a positive TPHA test. Active syphilis was found in 4.7%. In univariate analysis, CT was associated with having had any level of education (

    Comparison of pap smear, visual inspection with acetic acid, human papillomavirus DNA-PCR testing and cervicography

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    Objective: To assess the test qualities of four screening methods to detect cervical intra-epithelial neoplasia in an urban African setting. Method: Six hundred fiftythree women, attending a family planning clinic in Nairobi (Kenya), underwent four concurrent screening methods: pap smear, visual inspection with acetic acid (VIA), PCR for high risk human papillomavirus (HR HPV) and cervicography. The presence of cervical intra-epithelial neoplasia (CIN) was verified by colposcopy or biopsy. Result: Sensitivity (for CIN2 or higher) and specificity (to exclude any CIN or cancer) were 83.3% (95% CI [73.6, 93.0]) and 94.6% (95% CI [92.6, 96.5]), respectively, for pap smear; 73.3% (95% CI [61.8, 84.9]) and 80.0% (95% CI [76.6, 83.4]) for VIA; 94.4% (95% CI [84.6, 98.8]) and 73.9% (95% CI [69.7, 78.2]) for HR HPV; and 72.3% (95% CI [59.1, 85.6]) and 93.2% (95% CI [90.8, 95.7]) for cervicography. Conclusion: The pap smear had the highest specificity (94.6%) and HPV testing the highest sensitivity (94.4%). The visual methods, VIA and cervicography, were similar and showed an accuracy in between the former two tests

    Thermographic study of heat load asymmetries during MAST L-mode discharges

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    Abstract. A long wavelength range infrared camera (LWIR) has been installed on MAST to compliment the existing medium wave infrared system. Simultaneous LWIR/MWIR temperature measurements have been made in the lower and upper divertors of MAST. As expected, the LWIR system is less sensitive to disturbances from hot spots on the surface. A thorough correction of the surface effects using both systems has improved the reliability of the heat flux calculations in MAST. A careful assessment of the heat load asymmetries as a function of the magnetic geometry has been carried out during a variety of L-mode discharges (single and double null, reversed and forward field). In all cases, most of the energy arriving in the SOL goes to the outer divertor. The in/out power ratio is found to be different for lower and upper single null discharges with more power going to the outer divertor in the latter case. In addition, it is found that the heat flux profile width is different in the upper and lower divertor. The heat flux profile width at the secondary strike point increases with increasing δr sep

    Dissociative recombination and electron-impact de-excitation in CH photon emission under ITER divertor-relevant plasma conditions

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    For understanding carbon erosion and redeposition in nuclear fusion devices, it is important to understand the transport and chemical break-up of hydrocarbon molecules in edge plasmas, often diagnosed by emission of the CH A^2\Delta - X^2\Pi Ger\"o band around 430 nm. The CH A-level can be excited either by electron-impact or by dissociative recombination (D.R.) of hydrocarbon ions. These processes were included in the 3D Monte Carlo impurity transport code ERO. A series of methane injection experiments was performed in the high-density, low-temperature linear plasma generator Pilot-PSI, and simulated emission intensity profiles were benchmarked against these experiments. It was confirmed that excitation by D.R. dominates at T_e < 1.5 eV. The results indicate that the fraction of D.R. events that lead to a CH radical in the A-level and consequent photon emission is at least 10%. Additionally, quenching of the excited CH radicals by electron impact de-excitation was included in the modeling. This quenching is shown to be significant: depending on the electron density, it reduces the effective CH emission by a factor of 1.4 at n_e=1.3*10^20 m^-3, to 2.8 at n_e=9.3*10^20 m^-3. Its inclusion significantly improved agreement between experiment and modeling

    Survival of cervical cancer patients at Moi teaching and Referral Hospital, Eldoret in western Kenya

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    Background Cervical cancer is a major health burden and the second most common cancer after breast cancer among women in Kenya. Worldwide cervical cancer constitutes 3.1% of all cancer cases. Mortality rates are greatest among the low-income countries because of lack of awareness, screening and early-detection programs and adequate treatment facilities. The main aim was to estimate survival and determine survival predictors of women with cervical cancer and limited resources in western Kenya. Methods Retrospective charts review of women diagnosed with cervical cancer and follow-up for two years from the date of the histologic diagnosis. The outcome of interest was death or survival at two years. Kaplan Meier estimates of survival, log-rank test and Cox proportional hazards regression were used in the survival analysis. Results One hundred and sixty-two (162) participants were included in the review. The median duration was 0.8 (interquartile range (IQR) 0.3, 1.6) years. The mean age at diagnosis was 50.6 years (SD12.5). The mean parity was 5.9 (SD 2.6). Fifty percent (50%) did not have health insurance. Twenty six percent (26%) used hormonal contraceptives, 25.9% were HIV positive and 70% of them were on anti-retroviral treatment. The participants were followed up for 152.6 person years. Of the 162 women in the study, 70 (43.2%) died giving an overall incidence rate (IR) of 45.9 deaths per 100 person years of follow up. The hazard ratios were better for the patients who survived (0.44 vs 0.88, p-value \u3c 0.001), those who had medical insurance (0.70 vs 0.48, p-value = 0.007) and those with early stage at diagnosis (0.88 vs 0.39, p-value \u3c 0.001). Participants who were diagnosed at late stage of the disease according to the International Federation of Gynecology and Obstetrics staging for cervical cancer (FIGO stage 2B-4B) had more than eight times increased hazard of death compared to those who were diagnosed at early stage (1-2A): Hazard Ratio: 8.01 (95% CI 3.65, 17.57). Similarly, those who underwent surgical management had 84% reduced hazard of mortality compared to those who were referred for other modes of care: HR: 0.16 (95% CI: 0.07, 0.38). Conclusion: Majority of the participants were diagnosed late after presenting with symptoms. The 1 and 2-year survival probability after diagnosis of cervical cancer was 57% AND 45% respectively. It is imperative that women present early since surgery gives better prognosis or better still screening of all women prioritized
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