87 research outputs found

    Short-time homomorphic wavelet estimation

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    Successful wavelet estimation is an essential step for seismic methods like impedance inversion, analysis of amplitude variations with offset and full waveform inversion. Homomorphic deconvolution has long intrigued as a potentially elegant solution to the wavelet estimation problem. Yet a successful implementation has proven difficult. Associated disadvantages like phase unwrapping and restrictions of sparsity in the reflectivity function limit its application. We explore short-time homomorphic wavelet estimation as a combination of the classical homomorphic analysis and log-spectral averaging. The introduced method of log-spectral averaging using a short-term Fourier transform increases the number of sample points, thus reducing estimation variances. We apply the developed method on synthetic and real data examples and demonstrate good performance.Comment: 13 pages, 5 figures. 2012 J. Geophys. Eng. 9 67

    Screening for latent tuberculosis infection among undocumented immigrants in Swiss healthcare centres; a descriptive exploratory study

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    BACKGROUND: Migration is one of the major causes of tuberculosis in developed countries. Undocumented patients are usually not screened at the border and are not covered by a health insurance increasing their risk of developing the disease unnoticed. Urban health centres could help identify this population at risk. The objective of this study is to assess the prevalence of latent tuberculosis infection (LTBI) and adherence to preventive treatment in a population of undocumented immigrant patients. METHODS: All consecutive undocumented patients that visited two urban healthcare centres for vulnerable populations in Lausanne, Switzerland for the first time were offered tuberculosis screening with an interferon-gamma assay. Preventive treatment was offered if indicated. Adherence to treatment was evaluated monthly over a nine month period. RESULTS: Of the 161 participants, 131 (81.4%) agreed to screening and 125 had complete examinations. Twenty-four of the 125 patients (19.2%; CI95% 12.7;27.2) had positive interferon-gamma assay results, two of which had active tuberculosis. Only five patients with LTBI completed full preventive treatments. Five others initiated the treatment but did not follow through. CONCLUSION: Screening for tuberculosis infection in this hard-to-reach population is feasible in dedicated urban clinics, and the prevalence of LTBI is high in this vulnerable population. However, the low adherence to treatment is an important public health concern, and new strategies are needed to address this problem

    Enhanced Protective Efficacy of a Chimeric Form of the Schistosomiasis Vaccine Antigen Sm-TSP-2

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    The large extracellular loop of the Schistosoma mansoni tetraspanin, Sm-TSP-2, when fused to a thioredoxin partner and formulated with Freund's adjuvants, has been shown to be an efficacious vaccine against murine schistosomiasis. Moreover, Sm-TSP-2 is uniquely recognised by IgG1 and IgG3 from putatively resistant individuals resident in S. mansoni endemic areas in Brazil. In the present study, we expressed Sm-TSP-2 at high yield and in soluble form in E. coli without the need for a solubility enhancing fusion partner. We also expressed in E. coli a chimera called Sm-TSP-2/5B, which consisted of Sm-TSP-2 fused to the immunogenic 5B region of the hookworm aspartic protease and vaccine antigen, Na-APR-1. Sm-TSP-2 formulated with alum/CpG showed significant reductions in adult worm and liver egg burdens in two separate murine schistosomiasis challenge studies. Sm-TSP-2/5B afforded significantly greater protection than Sm-TSP-2 alone when both antigens were formulated with alum/CpG. The enhanced protection obtained with the chimeric fusion protein was associated with increased production of anti-Sm-TSP-2 antibodies and IL-4, IL-10 and IFN-γ from spleen cells of vaccinated animals. Sera from 666 individuals from Brazil who were infected with S. mansoni were screened for potentially deleterious IgE responses to Sm-TSP-2. Anti-Sm-TSP-2 IgE to this protein was not detected (also shown previously for Na-APR-1), suggesting that the chimeric antigen Sm-TSP-2/5B could be used to safely and effectively vaccinate people in areas where schistosomes and hookworms are endemic

    From entry to elite: The relative age effect in the Australian football talent pathway

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    © 2018 Sports Medicine Australia Objectives: This study aimed to assess the first instance and prevalence of the Relative Age Effect (RAE) in the male Australian Football (AF) talent development pathway through to the Australian Football League (AFL). Design: Retrospective cross-sectional analysis. Methods: Birthdate distribution was accessed from an U10–U12 AF academy trial (n = 514), U13–U19 AF academy players (n = 408), AFL state, national and international combines (n = 2989), AFL Rising Star nominees (n = 50) and the top ten AFL Brownlow vote recipients (n = 50) between 2013–2017. Results: Chi-squared analysis showed significant overrepresentation to early born players in the selection year for both quartile and half-year compared to the previously known distribution at different stages of the talent pathway. Odds ratio demonstrated bias to players born in quartiles one and two of the selection year compared to players born in quartile four in every cohort examined. Conclusions: RAEs appear between ages 10–12 in the male AF development pathway and continue to senior professional competition. RAEs are amplified as the competition for positions increases and at points where selection cut-offs occur. Interestingly, players receiving votes for the AFL's best and fairest award were 12.6 times more likely to be born in the first half of the year. This may suggest a latent effect, which has long term benefits for relatively older players. Nonetheless, the RAE affects career progression in a male AF talent pathway

    How effective is spotlighting for detecting the greater glider (Petauroides volans)?

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    The efficacy of spotlighting as a field survey technique for detecting the greater glider (Petauroides volans) was assessed by comparing the precise location of radio-tracked animals with locations determined simultaneously from spotlighting searches. Radio-collars were fitted to 20 greater gliders in three eucalypt patches embedded within an extensive radiata pine (Pinus radiata) plantation near Tumut in south-eastern New South Wales. Our success rate for detecting collared animals was low, even when survey effort was increased. These findings suggest that spotlighting underestimates actual population size. A further, properly designed study, in different forest types is needed to provide precise estimates of the magnitude of the bias in counts of P. volans obtained by spotlighting
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