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Risk Factors for Acute Otitis Media in Children Aged 0 to 5 Years in Parakou

International j.urnal of Otolaryngology and Head & Neck Surgery 2016年第2期5卷 73-78页

作者： Spero H. Raoul Hounkpatin j.lien Didier Adedemy Marius C. Flatin Senami Florine E. Awassi Sonia Lawson Afouda François Avakoudj. Wassi Adj.abi sogbadji j. vodouh. Faculty of Medicine University of Parakou Parakou Benin Faculy of Health Sciences University of Abomey-Calavi Cotonou Benin

Introduction: Acute otitis media (AOM) is one of the most common ENT childhood diseases. Obj.ctive: To identify risk factors for AOM in children aged 0 to 5 years. Methods: This research work was a cross-sectional, descriptive and analytical study. It focused on 2040 children aged 0 to 5 years from both sexes, who were healthy or sick, and living in the Local government of Parakou for at least one year. Those children were randomly selected in all three districts of Parakou. Results: Frequency of AOM was 2.8% and their prevalence was estimated at 16.3%. The identified risk factors were persistent or chronic cases of rhinitis, exposure to charcoal and wood smoke, low socioeconomic status, personal history of AOM, AOM history among the siblings, and children’s poor nutritional status. No relationship could be established between AOM occurrence and factors like sex, passive smoking, attendance of a day-care centre or stay in nursery, prematurity, exclusive breastfeeding and large number of siblings. Conclusion: The identification of those risk factors will help put in place appropriate measures to reduce AOM prevalence in Parakou.

关键词： Acute Otitis Media Prevalence Risk Factors Children

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Determination of Neutron Fluxes and Spectrum Shaping Factors in Irradiation Sites of Ghana’S Miniature Neutron Source Reactor (mnsr) by Activation Method After Compensation of Loss of Excess Reactivty

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World j.urnal of Nuclear Science and Technology 2011年第2期1卷 50-56页

作者： R.B.M. sogbadji B.j.B. Nyarko E.H.K. Akaho R. G. Abrefah Ghana Atomic Energy Commission National Nuclear Research Institute P.O. Box LG80 Legon Ghana

Accurate neutron flux values in irradiation channels of research reactors are very essential to their usage. The total neutron flux of the Ghana Research Reactor-1(GHARR-1) was measured after a beryllium reflector was added to its shim to compensate for excess reactivity loss. The thermal, epithermal and fast neutron fluxes were determined by the method of foil activation. The experimental samples with and without a cadmium cover of 1-mm thickness were irradiated in the isotropic neutron field of the irradiation sites of Ghana Research Reactor-1 facility. The induced activities in the sample were measured by gamma ray spectrometry with a high purity germanium detector. The necessary correction for gamma attenuation, thermal neutrons and resonance neutron self-shielding effects were taken into account during the experimental analysis. By defining cadmium cutoff energy of 0.55eV, Al-0.1% Au wires of negligible thickness were irradiated at 3kW to determine the neutron fluxes of two irradiation channels, outer channel 7 and inner channel 2 whose Neutron Shaping Factor (α) were found to be (0.037 ± 0.001) and (–0.961 ± 0.034). The neutron flux ratios at the inner irradiation site 2 were found to be, (25.308 ± 3.201) for thermal to epithermal neutrons flux, (0.179 ± 0.021) for epithermal to fast neutrons flux and (4.528 ± 0.524) for thermal to fast neutrons flux, in the outer irradiation site 7, the neutron flux ratios were found to be, (40.865 ± 3.622) for thermal to epithermal neutrons flux, (0.286 ± 0.025) for epithermal to fast neutrons flux and (11.680 ± 1.030) for thermal to fast neutrons flux.

关键词： Fluence Rate Foil Activation Neutron Self-Shielding Flux Ratio

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Delayed Neutrons Energy Spectrum Flux Profile of Nuclear Materials in Ghana’s Miniature Neutron Source Reactor Core

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World j.urnal of Nuclear Science and Technology 2011年第2期1卷 26-30页

作者： R.B.M. sogbadji R.G. Abrefah E. Ampomah-Amoako S.A. Birikorang S.E. Agbemava B.j.B. Nyarko H.C. Odoi Ghana Atomic Energy Commission National Nuclear Research Institute P.O. Box LG80 Legon Ghana

A slightly prompt critical nuclear reactor would increase the neutron flux exponentially at a high rate causing the reactor to become uncontrollable, however due to the delayed neutrons, it is possible to leave the reactor in a subcritical state as far as only prompt neutrons are concerned and to also sustain the chain reaction when it is going to die out. The delay neutron flux spectrum of the compact core of the Ghana’s miniature neutron source reactor (MNSR) was studied using the Monte Carlo method. 20,484 energy groups combined for all three categories of the energy distribution, thermal, slowing down and fast regions were modeled to create small energy bins. The moderator, the inner irradiation channels, the annulus beryllium reflector and the outer irradiation channels were the regions monitored. The delay thermal neutrons recorded its highest flux in the inner irradiation channel with an average flux of (4.0127 0.0076) × 1008 n/cm2?s, followed by the outer irradiation channel with an average flux of (2.4524 0.0049) × 1008 n/cm2?s. The beryllium reflector recorded the lowest flux in the thermal region. These values of the thermal energy range occurred in the energy range (0 – 0.625× 10 – 07) MeV. The inner irradiation channel again recorded the highest average flux of (1.2050 ± 0.0501) × 1007 n/cm2?s at the slowing down region in the energy range (0.821 – 6.94) MeV. The outer irradiation channel recorded the lowest flux in this region. In the fast energy region, (6.96 – 20) MeV, the core, where the moderator is found, the same trend was observed with the inner irradiation channel recording the highest flux at an average flux of (2.0647 ± 0.3260) × 1006 n/cm2?s .The outer irradiation channel recorded the second highest flux while the annulus beryllium reflector recorded very low flux in this region. The final k-effective contribution from only delay neutrons is 0.00834 with the delay neutron fraction being 0.01357 ± 0.00049, hence the Ghana MNSR has good safety

关键词： Radioactivity Doses water Gamma Spectroscopy Oil Areas Nigeria

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