22,006 research outputs found

    ACUTE OTITIS EXTERNA AS SEEN AT THE UNIVERSITY OF NIGERIA TEACHING HOSPITAL, ENUGU.

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    Aim: is to evaluate clinical features of AOE diagnosed in and to update the previous study from our facility.Methods: A prospective, clinical and laboratory study in a tertiary health facilityResults: A total of 3793 consecutive patients that attended the otorhinolaryngology clinics of the university of Nigeria teaching hospital Enugu during the period under study were assessed for clinical diagnosis of otitis externa. A total of 155 ears from127 patients were diagnosed clinically and confirmed by microbial studies as having acute otitis externa. There were 66 males and 61 females out of the 127 patients seen.71 ears had only bacteria isolated from the culture of their ear swab specimens, 28 fungus only and, 32 ears had both bacterial and fungal isolates while 24 ears had no isolates of microbes of the 3793 patients assessed.Conclusions: Acute otitis externa is a common disease in Enugu  with no gender biasand there were three times more cases of bacterial otitis externa than fungal otitis externa.

    Numerical analysis of microwave detection of breast tumours using synthetic focussing techniques

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    Microwave detection of breast tumours is a non-ionising and potentially low-cost and more certain alternative to X-ray mammography. Analogous to ground penetrating radar (GPR), microwaves are transmitted using an antenna array and the reflected signals, which contain reflections from tumours, are recorded. The work presented here employs a post reception synthetically focussed detection method developed for land mine detection (R. Benjamin et al., IEE Proc. Radar, Sonar and Nav., vol. 148, no.4, pp. 233-40, 2001); all elements of an antenna array transmit a broadband signal in turn, the elements sharing a field of view with the current transmit element then record the received signal. By predicting the path delay between transmit and receive antennas via any desired point in the breast, it is then possible to extract and time-align all signals from that point. Repeated for all points in the breast, this yields an image in which the distinct dielectric properties of malignant tissue are potentially visible. This contribution presents a theoretical evaluation of the breast imaging system using FDTD methods. The FDTD model realistically models a practical system incorporating wide band antenna elements. One major challenge in breast cancer detection using microwaves is the clutter arising from skin interface. Deeply located tumours can be detected using windowing techniques (R. Nilavalan et al., Electronics Letters, vol. 39, pp. 1787-1789, 2003); however tumours closer to the skin interface require additional consideration, as described herein

    Particle production in the outflow of a midlatitude storm

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    The concentrations of atmospheric gases and condensation nuclei (CN) or aerosol in the outflow of a storm were measured aboard a NASA DC-8 aircraft, as described in a companion paper [Twohy et al., 2002]. The data are used here to study the production of the aerosol. Major fluctuations in CN concentration are observed, in correlation with gas-phase species, but these are shown to arise as the result of the mixing of two distinct air masses. It is deduced that the CN originated in a storm outflow air mass and that its concentration before mixing was approximately uniform over a flight distance of about 200 km. The formation of the aerosol by nucleation followed by growth and coagulation is analyzed assuming that it consists of water and sulphuric acid produced locally by the oxidation of SO2. The analysis uses analytic models, and it is concluded that a 5 min burst of nucleation was followed by growth and coagulation over a period of about 5 hours. Both the mass and number concentrations of the observed aerosol can be reproduced by this analysis within a timescale consistent with that of the storm. The final number concentration is very insensitive to the initial SO2 concentration

    Multilayer and conformal antennas using synthetic dielectric substrates

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    Finite difference time domain simulation of the Earth-ionosphere resonant cavity: Schumann resonances

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