An evaluation of conventional and no-tillage systems on soil physical conditions.

Thesis (M.Sc.)-University of Natal, Pietermaritzurg, 2003.The use of no-tillage (NT) system has increased in the past few years in South Africa, but its effects on soil physical conditions have not been adequately documented. This study was undertaken to ascertain these effects, as compared to Conventional tillage (CT) system. Several sites were selected in the Bergville and Winterton areas of the midlands of KwaZulu-Natal, and at the Cedara Agricultural Research Station. NT generally increased bulk density in the topsoil and this altered total porosity and poresize distribution. Water retention, organic C and aggregate stability were increased under NT, partly due to the maintenance of the mulch cover on the surface soil. Organic C and aggregate stability were positively correlated with each other. Differences in bulk density between tillage systems with soil depth did not clearly indicate where soil compaction had occurred. Significant differences in soil compaction between treatments were, however, illustrated by changes in soil penetration resistance (SPR), especially at the. 150 mm depth. In addition, depending on the soil type, SPR was greater in the topsoil under NT than CT. It was suggested that conversion from CT to NT was carried out when the topsoil of the CT-fields was structurally poor, due to a previous history of continuous CT. Tractor traffic under CT and repeated tillage when the soil was wet had, in some cases, resulted in the formation of a compacted layer at the depth of cultivation. In clay soils, this has resulted in subsoil compaction. The formation of compacted layers caused major changes to pore size distribution and continuity and this resulted in substantially reduced hydraulic conductivity, infiltration rate,air-filled porosity and air permeability. It was concluded that compacted subsoil layers need to be broken up prior to conversion from CT to NT, and that compaction in the surface soil under NT has occurred and, in some cases, this will be a limitation to crop production. The use of minimum tillage systems should be considered and researched in these cases.Page 69 (colour photographs) missing from origina

KinSPEAK: Improving speech recognition for Kinyarwanda via semi-supervised learning methods

Despite recent availability of large transcribed Kinyarwanda speech data, achieving robust speech recognition for Kinyarwanda is still challenging. In this work, we show that using self-supervised pre-training, following a simple curriculum schedule during fine-tuning and using semi-supervised learning to leverage large unlabelled speech data significantly improve speech recognition performance for Kinyarwanda. Our approach focuses on using public domain data only. A new studio-quality speech dataset is collected from a public website, then used to train a clean baseline model. The clean baseline model is then used to rank examples from a more diverse and noisy public dataset, defining a simple curriculum training schedule. Finally, we apply semi-supervised learning to label and learn from large unlabelled data in five successive generations. Our final model achieves 3.2% word error rate (WER) on the new dataset and 15.6% WER on Mozilla Common Voice benchmark, which is state-of-the-art to the best of our knowledge. Our experiments also indicate that using syllabic rather than character-based tokenization results in better speech recognition performance for Kinyarwanda.Comment: 9 pages, 2 figures, 5 table

Morphological Disambiguation from Stemming Data

Morphological analysis and disambiguation is an important task and a crucial preprocessing step in natural language processing of morphologically rich languages. Kinyarwanda, a morphologically rich language, currently lacks tools for automated morphological analysis. While linguistically curated finite state tools can be easily developed for morphological analysis, the morphological richness of the language allows many ambiguous analyses to be produced, requiring effective disambiguation. In this paper, we propose learning to morphologically disambiguate Kinyarwanda verbal forms from a new stemming dataset collected through crowd-sourcing. Using feature engineering and a feed-forward neural network based classifier, we achieve about 89% non-contextualized disambiguation accuracy. Our experiments reveal that inflectional properties of stems and morpheme association rules are the most discriminative features for disambiguation

Trade Liberalisation in SADC and the Economic Benefits of belonging to an RTA: The case of Tanzania

This paper examines the dynamics of trade liberalisation in the Southern Development Community (SADC), region and the economic benefits that Tanzania derives from SADC membership. The paper uses qualitative analysis and trade indices. The findings show that SADC is far behind its agreed schedule of transforming the region into a customs union and SADC intra-regional trade is very low, only South Africa and Mozambique seem to carry the potential to increase intraregional trade and benefit from SADC in the short run. On the other hand, Tanzania's economic benefits from SADC membership have remained trivial, though her exports and market share have been steadily increasing since the mid 1990s. However, Tanzania does not suffer adversely from the dual membership of EAC and SADC regions, despite its membership in the two overlapping RTAs making its trade regime complex because tariff reductions under EAC customs union are not compatible with SADC's hence resulting in problems in implementing the SADC Trade Protocol. However, the country may not need to withdraw  its membership from either EAC or SADC due to signs of good prospect in the long run under the proposed harmonisation of the EAC and SADC trade regime through the Tripartiite Free Trade Area arrangement (COMESA-EAC-SADC)

Prevalence of Oral and Maxillofacial Injuries among Patients Managed at a Teaching Hospital in Rwanda

Background: Oral and maxillofacial injuries have been shown worldwide to be a major cause of disability and orofacial deformity. The magnitude and causes of oral and maxillofacial injuries varies from one country to another or even within the same country depending on prevailing conditions such as socioeconomic, cultural and environmental factors. Objectives: To assess the magnitude and etiology of oral and maxillofacial injuries in relation to socio-demographic data among patients attending Kigali University Teaching Hospital (CHUK), Dental department. Methodology: A prospective cross-sectional study recruited a total of 182 subjects who were interviewed to obtained information on socio-demographic data and the cause of the inflicted injuries. Diagnoses of the different types of hard and soft tissue injuries were done by clinical examination of patient and where necessary radiographic investigations were requested to confirm hard tissue fractures. All collected information was recorded in the clinical form. Gathered data was coded and entered into a computer and analyzed using SPSS version 17. Results: Prevalence of oral and maxillofacial injuries was 16%. Most patients (53.8%) were in 21-30 age group with a male to female ratio of 2.2:1. The commonest hard tissue injuries sustained were dentoalveolar and mandibular fracture at 59.3% and 19.8% respectively, while trauma to the lip was the commonest (38.7%) soft tissue injury among the patients. Road traffic accident collectively accounted for 59.8% of all the etiological factors of oral and maxillofacial injuries. Conclusion and recommendations: The prevalence of oral and maxillofacial injuries was 16%. Road Traffic Accident accounted for most of the injuries in the study population. Prevention strategies of maxillofacial injuries among others should emphasize on reduction of road traffic accidents with particular attention to motorcycle and motor vehicle accidents.Key words: Prevalence, oral, maxillofacial, injuries, Rwand

A Case of Imported Plasmodium malariae Malaria

Malaria, the most common vector-borne parasite infection worldwide, results from infection by Plasmodium species. Approximately 80% of malaria cases are caused by P. vivax, which is broadly distributed from tropical to temperate regions; P. falciparum is the second most common infectious species. P. malariae and P. ovale are responsible for a relatively small proportion of malaria cases. Here, we report the case of a 23-yr-old Korean woman who acquired a P. malariae infection while visiting the Republic of Ghana in West Africa for business. She was diagnosed with P. malariae malaria on the basis of peripheral blood smear (PBS) and species-specific conventional and real-time PCR assays for 18S rRNA. She was treated with hydroxychloroquine, and the resulting PBS examination on day 2 suggested that negative conversion occurred. At her 1-month follow-up, however, both the PBS examination and molecular test for malaria demonstrated recurrent parasitemia. We started rescue therapy with mefloquine, and the patient recovered successfully. This is an important finding suggesting possible late recrudescence of a chloroquine-resistant P. malariae strain identified not only by its morphological features, but also by molecular tests

Identification of phenolic compounds and determination of antioxidant activity in extracts and infusions of salvia leaves

Francik, Slawomir/0000-0002-4535-9450; NZEYIMANA, Abdoul/0000-0002-1887-510X; Knapczyk, Adrian/0000-0002-1134-6299; Francik, Renata/0000-0002-7071-8072; Bystrowska, Beata/0000-0001-6501-8656WOS:000602822400001PubMed: 33352787The influence of harvest period and drying method of Salvia officinalis L. leaves on the content of essential oils, polyphenols and antioxidant properties was investigated. Sage leaves were collected twice during plant blossoming (in June and July) and dried traditionally in natural conditions and at 35 degrees C. Antioxidant activity was assayed in methanol-acetone extracts and infusions of dried leaves with the use of free radical scavenging activity (DPPH) and ferric reducing antioxidant power (FRAP) technique. Total phenolic content in extracts as well as in infusions was determined by the means of Folin-Ciocalteu method. Based on the LC/MS analysis, the polyphenol compounds present in both extracts and in infusions were identified. The extracts contained more polyphenols and were characterized by higher antioxidant activity than infusions. in the extracts significant amount of ferulic acid was found, which was influenced both by the harvest period and drying method. The amount of ferulic acid found in extracts obtained from the June leaves dried traditionally was three times lower (6.185 mu g/g DW) than in extracts from July leaves dried in the same conditions. Harvest period had a significant effect on the essential oils' content, leaves collected in July contained 15% more oils than those collected in June.Ministry of Science and Higher Education of the Republic of PolandMinistry of Science and Higher Education, PolandThe study was financed by Ministry of Science and Higher Education of the Republic of Poland