120 research outputs found

    Sand dredging impact on macrobenthic invertebrates of a hallowed river in Delta State of Nigeria

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    River Ethiope is one of the most revered water bodies in Delta State by communities along its course. Macroinvertebrate samples were collected from threes communities; Obi- Iloh, Ebedei-Adonishaka, Ebedei Obi-Ukwuole designated as Station 1, 2 and 3 respectively, that forbids women entrance but allows men folk to sand dredge. The survey conducted between March and April, 2015, identified 17 taxa of macro invertebrate with 219 individuals. Of the nine order, Hemiptera constituted the most abundant set 42.25%, followed by Decapoda 16.90%, Coleoptera 11.74%, Plecoptera and Arachnida 6.57%, Odonata 5.16%, Diptera 4.23%, Annelida(Lumbriculida and Arhynchobdelida) 3.76% and the least Trichoptera 2.82%. However, non-statistical significant richness exists among these organisms at the stations (p ≥0.05). Computed biological indices and lower macro invertebrates census revealed that the macro invertebrates were more abundant in stations 3 and 1 than in station 2, identifying the last two stations as unstable and moderately deteriorated. The enlisted significant correlated variables expressed manifold hydrological factors pinpointing human disturbance as impact

    Evaluation of hermetic technologies in the control of insect infestation and mycotoxin contamination in stored maize grains: Presentation

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    Grain losses due to moulds during on-farm storage increase food insecurity, result in economic losses, negatively affect farmers’ livelihoods, and increase exposure to mycotoxins that can harm human and animal health. Hermetic storage technologies provide a reliable solution for maize grain that may also preserve food safety. Several studies report the effectiveness of these technologies against post-harvest insects in Africa but provide limited evidence on effectiveness against mould proliferation and mycotoxin contamination. Hermetic technologies were superior to farmer practice in reducing insect infestations and mycotoxin accumulation. Among hermetic technologies, there were no significant differences (P>0.05) in performance between metal silos and hermetic bags for mycotoxin accumulation and insect infestation regardless of the mode of infestation. In non-inoculated grain, fungal populations were varied but included mycotoxin-producing Aspergillus and Fusarium spp., indicating that the grain was naturally contaminated and acted as a good reservoir for these fungi. Mycotoxin levels increased with higher moisture even in non-inoculated grain. Meanwhile, aflatoxin and fumonisin levels at 4 months were not significantly different from baseline values in dry inoculated grain across all storage technologies (P>0.05), indicating that hermetic technologies can prevent mycotoxin contamination in dry grain for at least 4 months of storage. Aflatoxin and fumonisin were significantly higher by 1.69 ppb and 0.25 ppm respectively in non-inoculated grains at high moisture indicating the need to adequately dry grain before storage in hermetic technologies. This trend was observed collectively in all the technologies registering 2.03 ppb and 0.311 ppm respectively. In inoculated grains at high moisture, there was an increase in aflatoxin in both hermetic treatments and the control by 5.7 ppb and 12.14 ppb respectively. Therefore, a trial was conducted to compare hermetic technologies with farmer practice in their effectiveness against both insect infestation and mycotoxin contamination.Grain losses due to moulds during on-farm storage increase food insecurity, result in economic losses, negatively affect farmers’ livelihoods, and increase exposure to mycotoxins that can harm human and animal health. Hermetic storage technologies provide a reliable solution for maize grain that may also preserve food safety. Several studies report the effectiveness of these technologies against post-harvest insects in Africa but provide limited evidence on effectiveness against mould proliferation and mycotoxin contamination. Hermetic technologies were superior to farmer practice in reducing insect infestations and mycotoxin accumulation. Among hermetic technologies, there were no significant differences (P>0.05) in performance between metal silos and hermetic bags for mycotoxin accumulation and insect infestation regardless of the mode of infestation. In non-inoculated grain, fungal populations were varied but included mycotoxin-producing Aspergillus and Fusarium spp., indicating that the grain was naturally contaminated and acted as a good reservoir for these fungi. Mycotoxin levels increased with higher moisture even in non-inoculated grain. Meanwhile, aflatoxin and fumonisin levels at 4 months were not significantly different from baseline values in dry inoculated grain across all storage technologies (P>0.05), indicating that hermetic technologies can prevent mycotoxin contamination in dry grain for at least 4 months of storage. Aflatoxin and fumonisin were significantly higher by 1.69 ppb and 0.25 ppm respectively in non-inoculated grains at high moisture indicating the need to adequately dry grain before storage in hermetic technologies. This trend was observed collectively in all the technologies registering 2.03 ppb and 0.311 ppm respectively. In inoculated grains at high moisture, there was an increase in aflatoxin in both hermetic treatments and the control by 5.7 ppb and 12.14 ppb respectively. Therefore, a trial was conducted to compare hermetic technologies with farmer practice in their effectiveness against both insect infestation and mycotoxin contamination

    Performance evaluation of the time delay digital tanlock loop architectures

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    This article presents the architectures, theoretical analyses and testing results of modified time delay digital tanlock loop (TDTLs) system. The modifications to the original TDTL architecture were introduced to overcome some of the limitations of the original TDTL and to enhance the overall performance of the particular systems. The limitations addressed in this article include the non-linearity of the phase detector, the restricted width of the locking range and the overall system acquisition speed. Each of the modified architectures was tested by subjecting the system to sudden positive and negative frequency steps and comparing its response with that of the original TDTL. In addition, the performance of all the architectures was evaluated under noise-free as well as noisy environments. The extensive simulation results using MATLAB/SIMULINK demonstrate that the new architectures overcome the limitations they addressed and the overall results confirmed significant improvements in performance compared to the conventional TDTL system

    Reproductive potential of fall armyworm Spodoptera frugiperda (J.E. Smith) and effects of feeding on diverse maize genotypes under artificial infestation

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    Fall armyworm (FAW) Spodoptera frugiperda (J.E. Smith) has become a major threat to maize production in Africa. In this study, six maize genotypes were assessed for their resistance to FAW under artificial infestation in both laboratory and net house conditions. These included two FAW-tolerant hybrids (CKHFAW180294 and CKH191221), two commercial hybrids (WE2115 and CKH10717), and two open-pollinated varieties (ZM523 and KDV4). Larval development time and reproductive potential were assessed on maize leaves in the laboratory and a life table for FAW was constructed. The maize genotypes were also artificially infested with three FAW neonates at two phenological stages (V5 and V7) and reproductive stage (R1) in the net house. Leaf and ear damage scores were recorded on a scale of 1–9. Larval development time varied significantly between maize genotypes with the highest on CKH191221 (16.4 days) and the lowest on KDV4 (13.7 days). The intrinsic rate of natural increase for life tables varied from 0.24 on CKH191221 to 0.41 on KDV4. Mean generation time of FAW ranged from 17.6 to 22.8 days on KDV4 and CKH191221, respectively. Foliar damage was the lowest on CKH191221, and the highest on KDV4 at V7 infestation stage in week 1. CKH191221 had the lowest ear damage score, whereas ZM523 had the highest scores at V5 infestation stage. The highest and lowest yield reductions were observed on ZM523 (64%) at V7 infestation stage and CKHFAW180294 (6%) at R1 infestation stage, respectively. The results indicated the potential for developing tropical mid-altitude maize germplasm with native genetic resistance to FAW

    Dissection aortique anevrismale chez un adulte infecte par le VIH-1 dans le cadre d'un syndrome de reconstitution immune avec tuberculose

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    We here report the case of a 35-year old man with HIV-1 but with no previous medical-surgical history hospitalized in Abidjan, Cote d'Ivoire, due to fever, cough, dyspnea, chest pain and unfolding of the aortic arch observed on chest x-ray a week after having started antiretroviral therapy (ART). CT angiography of the thoracic aorta showed overall, extended aortic ectasia with mural thrombus. Transesophageal echocardiography objectified type A ascending aortic dissection (Stanford classification). The diagnosis of tuberculosis was confirmed based on Mycobacterium tuberculosis culture isolation. Eight years after, the patient was still alive without surgical treatment and complained of intermittent chest pain. Blood pressure was stable with moderate renal failure. We here report a rare case of aortic aneurism dissection in an adult patient with tuberculosis infected with HIV-1 during immune reconstitution inflammatory syndrome

    Anapole nanolasers for mode-locking and ultrafast pulse generation

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    Nanophotonics is a rapidly developing field of research with many suggestions for a design of nanoantennas, sensors and miniature metadevices. Despite many proposals for passive nanophotonic devices, the efficient coupling of light to nanoscale optical structures remains a major challenge. In this article, we propose a nanoscale laser based on a tightly confined anapole mode. By harnessing the non-radiating nature of the anapole state, we show how to engineer nanolasers based on InGaAs nanodisks as on-chip sources with unique optical properties. Leveraging on the near-field character of anapole modes, we demonstrate a spontaneously polarized nanolaser able to couple light into waveguide channels with four orders of magnitude intensity than classical nanolasers, as well as the generation of ultrafast (of 100 fs) pulses via spontaneous mode locking of several anapoles. Anapole nanolasers offer an attractive platform for monolithically integrated, silicon photonics sources for advanced and efficient nanoscale circuitry

    Performance of Bt maize event MON810 in controlling maize stem borers Chilo partellus and Busseola fusca in Uganda

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    Stem borers are major insect pests of maize in Uganda. A study was conducted in 2014–2016 to assess the performance of Bt hybrids expressing Cry1Ab (event MON810) against the two major stem borer species in Uganda – the African stem borer (Busseola fusca) and the spotted stem borer (Chilo partellus) – under artificial infestation. The study comprised 14 non-commercialized hybrids, including seven pairs of Bt and non-Bt hybrids (isolines), three non-Bt commercial hybrids and a conventional stem borer resistant check. All stem borer damage parameters (leaf damage, number of internodes tunneled and tunnel length) were generally significantly lower in Bt hybrids than in their isolines, the conventionally resistant hybrid, and local commercial hybrids. Mean yields were significantly higher by 29.4–80.5% in the Bt hybrids than in the other three categories of non-Bt hybrids. This study demonstrated that Bt maize expressing Cry1Ab protects against leaf damage and can limit entry of stem borers into the stems of maize plants, resulting in higher yield than in the non-transgenic hybrids. Thus, Bt maize has potential to contribute to the overall management package of stem borers in Uganda

    Efficacy and Safety of Artemether in the Treatment of Chronic Fascioliasis in Egypt: Exploratory Phase-2 Trials

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    Fasciola hepatica and F. gigantica are two liver flukes that parasitize herbivorous large size mammals (e.g., sheep and cattle), as well as humans. A single drug is available to treat infections with Fasciola flukes, namely, triclabendazole. Recently, laboratory studies and clinical trials in sheep and humans suffering from acute fascioliasis have shown that artesunate and artemether (drugs that are widely used against malaria) also show activity against fascioliasis. Hence, we were motivated to assess the efficacy and safety of oral artemether in patients with chronic Fasciola infections. The study was carried out in Egypt and artemether administered according to two different malaria treatment regimens. Cure rates observed with 6×80 mg and 3×200 mg artemether were 35% and 6%, respectively. In addition, high efficacy was observed when triclabendazole, the current drug of choice against human fascioliasis, was administered to patients remaining Fasciola positive following artemether treatment. Concluding, monotherapy with artemether does not represent an alternative to triclabendazole against fascioliasis, but its role in combination chemotherapy regimen remains to be investigated
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