117 research outputs found

    Improvements in Blast Fragmentation Models Using Digital Image Processing

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    One of the fundamental requirements for being able to optimise blasting is the ability to predict fragmentation. An accurate blast fragmentation model allows a mine to adjust the fragmentation size for different downstream processes (mill processing versus leach, for instance), and to make real time adjustments in blasting parameters to account for changes in rock mass characteristics (hardness, fracture density, fracture orientation, etc). A number of blast fragmentation models have been developed in the past 40 years such as the Kuz-Ram model [1]. Fragmentation models have a limited usefulness at the present time because: 1. The input parameters are not the most useful for the engineer to determine and data for these parameters are not available throughout the rock mass. 2. Even if the input parameters are known, the models still do not consistently predict the correct fragmentation. This is because the models capture some but not all of the important rock and blast phenomena. 3. The models do not allow for ‘tuning’ at a specific mine site. This paper describes studies that are being conducted to improve blast fragmentation models. The Split image processing software is used for these studies

    An Evaluation of the Performance and Acceptability of Three LED Fluorescent Microscopes in Zambia: Lessons Learnt for Scale-Up

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    The World Health Organization recommends the roll-out of light-emitting diode (LED) fluorescent microscopes (FM) as an alternative to light microscopes in resource-limited settings. We evaluated the acceptability and performance of three LED FMs after a short orientation among laboratory technicians from government health centers in Zambia. Sixteen technicians with varied light microscopy experience were oriented to FMs and divided into groups; each group read a different set of 40 slides on each LED FM (Primo Star iLEDâ„¢, Luminâ„¢, FluoLEDâ„¢) and on a reference mercury-vapor FM (Olympus BX41TF). Slide reading times were recorded. An experienced FM technician examined each slide on the Olympus BX41TF. Sensitivity and specificity compared to TB culture were calculated. Misclassification compared to the experienced technician and inter-rater reliability between trainees was assessed. Trainees rated microscopes on technical aspects. Primo Star iLEDâ„¢, FluoLEDâ„¢ and Olympus BX41TF had comparable sensitivities (67%, 65% and 65% respectively), with the Luminâ„¢ significantly worse (56%; p<0.05). Specificity was low for trainees on all microscopes (75.9%) compared to the experienced technician on Olympus BX41TF (100%). Primo Star iLEDâ„¢ had significantly less misclassification (21.1% p<0.05) than FluoLEDâ„¢ (26.5%) and Luminâ„¢ (26.8%) and significantly higher inter-rater reliability (0.611; p<0.05), compared to FluoLEDâ„¢ (0.523) and Luminâ„¢ (0.492). Slide reading times for LED FMs were slower than the reference, but not significantly different from each other. Primo Star iLEDâ„¢ rated highest in acceptability measures, followed by FluoLEDâ„¢ then Luminâ„¢. Primo Star iLEDâ„¢ was consistently better than FluoLEDâ„¢ and Luminâ„¢, and performed comparably to the Olympus BX41TF in all analyses, except reading times. The Luminâ„¢ compared least favorably and was thought unacceptable for use. Specificity and inter-rater reliability were low for all microscopes suggesting that a brief orientation was insufficient in this setting. These results provide important data for resource-limited settings to consider as they scale-up LED FMs

    Screening for tuberculosis and testing for human immunodeficiency virus in Zambian prisons

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    Objective: To improve the Zambia Prisons Service's implementation of tuberculosis screening and human immunodeficiency virus (HIV) testing. Methods: For both tuberculosis and HIV, we implemented mass screening of inmates and community-based screening of those residing in encampments adjacent to prisons. We also established routine systems – with inmates as peer educators – for the screening of newly entered or symptomatic inmates. We improved infection control measures, increased diagnostic capacity and promoted awareness of tuberculosis in Zambia's prisons. Findings: In a period of 9 months, we screened 7638 individuals and diagnosed 409 new patients with tuberculosis. We tested 4879 individuals for HIV and diagnosed 564 cases of infection. An additional 625 individuals had previously been found to be HIV-positive. Including those already on tuberculosis treatment at the time of screening, the prevalence of tuberculosis recorded in the prisons and adjacent encampments – 6.4% (6428/100 000) – is 18 times the national prevalence estimate of 0.35%. Overall, 22.9% of the inmates and 13.8% of the encampment residents were HIV-positive. Conclusion: Both tuberculosis and HIV infection are common within Zambian prisons. We enhanced tuberculosis screening and improved the detection of tuberculosis and HIV in this setting. Our observations should be useful in the development of prison-based programmes for tuberculosis and HIV elsewhere

    Re-envisioning Tangintebu Theological College in the context of climate change: An emerging model of coconut theological education and ministerial formation

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    This article engages through an interdisciplinary approach to re-envision Tangintebu Theological College’s (TTC) model of theological education in the context of climate change in Kiribati. It utilises the anthropological theory of symbolic interactionism within missiological, cultural and, theological studies of climate change. It argues for the coconut tree as an appropriate cultural conceptual metaphorical idiom for translating and understanding Christian faith and shaping a theological pedagogy within the Kiribati context of climate change. The coconut image is an indigenous, holistic way of knowing and learning informed by Kiribati cosmology embedded within people’s experiences and understanding of the coconut tree. Its life-centeredness has the potential to contextualise the theological curriculum and teaching methodology to assist in equipping theological students with climate change-sensitive approaches. The qualitative method was utilised to allow participants to reflect on their experiences of climate change in relation to the mission of the church. The data that informs this article was generated through unstructured interviews and focus group discussions with members of the Kiribati Uniting Church (KUC). The data was analysed using symbolic interactionism. The results suggest that the Kiribati people symbolically interact with God through their understanding of the coconut tree, which is conceived as the embodiment of God’s presence. It became clear that while this world view informs the faith of members of the KUC, the TTC curriculum has sidelined it, resulting in miseducation of pastors because this omission means they are not equipped to engage with the challenge of climate change. The participants argued that there is an urgent need to understand theological education and ministerial formation within the indigenous framework of Kiribati coconut imagination that is embedded in the promotion of justice and equitable society not only for human beings but for all of God’s creation through symbolic interaction with the presence of God in the coconut

    Response of six common beans cultivars to phosphate and potassium fertilization in Lichinga, Niassa, Mozambique.

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    A field experiment was conducted to check out the response of the common bean BRS 293 Pontal to basic fertilization with Phosphorus (P) and Potassium, in the environmental conditions of Lichinga, Niassa, Mozambique. A complete factorial 5x4 was used, with five rates of P2O5 (0, 35, 70, 140, and 280 kg/ha, as Triple Superphosphate) and four rates of K2O (0, 50, 100 and 200 kg/ha, as Potassium Chloride). The experimental area was also fertilized with 90 kg/ha of Nitrogen (N), as Urea, spliced in 23 kg N/ha at planting and 67 kg N/ha 20 days after plants emergency. Each treatment was replicated four time in the field, in randomized blocks (18 m2 each, with five liner of six lineal meters each, spaced 0,45 cm, with nine seeds seeded per meter). At harvest (area of 3 m within the central lines), it was evaluated the plant final stand, degree of lodging, number of pods per plant, number of grains per pod, weight of 100 grains, and productivity. Based in the analysis of the data, it is concluded that maximum productivity, equivalent to 3,616 kg of grains/ha, would be obtained with a combination of 406 kg/ha of P2O5 and 43 kg/ha of K2O. Such rate is above what would be expected, which indicates that new studies would be necessary for better recommendation of P2O5 fertilization in this area

    Response of six common beans cultivars to phosphate and potassium fertilization in Lichinga, Niassa, Mozambique.

    Get PDF
    A field experiment was conducted to check out the response of the common bean BRS 293 Pontal to basic fertilization with Phosphorus (P) and Potassium, in the environmental conditions of Lichinga, Niassa, Mozambique. A complete factorial 5x4 was used, with five rates of P2O5 (0, 35, 70, 140, and 280 kg/ha, as Triple Superphosphate) and four rates of K2O (0, 50, 100 and 200 kg/ha, as Potassium Chloride). The experimental area was also fertilized with 90 kg/ha of Nitrogen (N), as Urea, spliced in 23 kg N/ha at planting and 67 kg N/ha 20 days after plants emergency. Each treatment was replicated four time in the field, in randomized blocks (18 m2 each, with five liner of six lineal meters each, spaced 0,45 cm, with nine seeds seeded per meter). At harvest (area of 3 m within the central lines), it was evaluated the plant final stand, degree of lodging, number of pods per plant, number of grains per pod, weight of 100 grains, and productivity. Based in the analysis of the data, it is concluded that maximum productivity, equivalent to 3,616 kg of grains/ha, would be obtained with a combination of 406 kg/ha of P2O5 and 43 kg/ha of K2O. Such rate is above what would be expected, which indicates that new studies would be necessary for better recommendation of P2O5 fertilization in this area

    Genetic diversity and population structure of the African catfish, <i>Clarias gariepinus</i> (Burchell, 1822) in Kenya: implication for conservation and aquaculture

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    African catfish, Clarias gariepinus, is an important species in aquaculture and fisheries in Kenya. Mitochondrial D-loop control region was used to determine genetic variation and population structure in samples of C. gariepinus from 10 sites including five natural populations (Lakes Victoria (LVG), Kanyaboli (LKG), Turkana (LTA), Baringo (LBA) and Jipe (LJP), and five farms (Sangoro Aquaculture Center (SAN), Sagana Aquaculture Centre (SAG), University of Eldoret Fish Farm (UoE), Kibos Fish Farm (KIB), and Wakhungu Fish Farm (WKU)) in Kenya. Similarly, samples from eight localities (four natural populations: LVG/LKG, LTA, LBA, and four farmed: SAN, SAG, KIB, UoE) were genotyped using six microsatellite DNA loci. For the D-loop control region, samples from natural sites exhibited higher numbers of haplotypes and haplotype diversities compared to farmed samples, and 88.2% of haplotypes were private. All except LJP and LTA shared haplotypes, and the highest number of shared haplotypes (8) was detected in KIB. The 68 haplotypes we found in 268 individuals grouped into five phylogenetic clades: LVG/LKG, LTA, LBA, LJP and SAG. Haplotypes of farmed C. gariepinus mostly have haplotypes typical of LVG/LKG, and some shared haplotypes of the LBA population. Microsatellite analysis showed farmed samples have higher numbers of alleles than natural samples, but higher observed and expected heterozygosity levels were found in samples of natural populations. Fifteen pair-wise comparisons had significantly different FST values. All samples were in Hardy-Weinberg equilibrium. Samples from the eight localities grouped into four genetic clusters (LVG/LKG, LTA, LBA and SAG), indicating genetically distinct populations, which should be considered for aquaculture and conservation

    Maternity waiting homes as part of a comprehensive approach to maternal and newborn care: a cross-sectional survey

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    Abstract Background Increased encounters with the healthcare system at multiple levels have the potential to improve maternal and newborn outcomes. The literature is replete with evidence on the impact of antenatal care and postnatal care to improve outcomes. Additionally, maternity waiting homes (MWHs) have been identified as a critical link in the continuum of care for maternal and newborn health yet there is scant data on the associations among MWH use and antenatal/postnatal attendance, family planning and immunization rates of newborns. Methods A cross-sectional household survey was conducted to collect data from women who delivered a child in the past 13 months from catchment areas associated with 40 healthcare facilities in seven rural Saving Mothers Giving Life districts in Zambia. Multi-stage random sampling procedures were employed with a final sample of n = 2381. Logistic regression models with adjusted odds ratios and 95% confidence intervals were used to analyze the data. Results The use of a MWH was associated with increased odds of attending four or more antenatal care visits (OR = 1.45, 95% CI = 1.26, 1.68), attending all postnatal care check-ups (OR = 2.00, 95% CI = 1.29, 3.12) and taking measures to avoid pregnancy (OR = 1.31, 95% CI = 1.10, 1.55) when compared to participants who did not use a MWH. Conclusions This is the first study to quantitatively examine the relationship between the use of MWHs and antenatal and postnatal uptake. Developing a comprehensive package of services for maternal and newborn care has the potential to improve acceptability, accessibility, and availability of healthcare services for maternal and newborn health. Maternity waiting homes have the potential to be used as part of a multi-pronged approach to improve maternal and newborn outcomes. Trial registration National Institutes of Health Trial Registration NCT02620436, Impact Evaluation of Maternity Homes Access in Zambia, Date of Registration - December 3, 2015.https://deepblue.lib.umich.edu/bitstream/2027.42/152216/1/12884_2019_Article_2384.pd
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