Optical properties of F centers in KCN crystal

Absorption, excitation and emission spectra of F centers in KCN were measured between 4.5-175 K. Due to the cubic to orthorhombic structural phase transition at 168 K, the F band splits into 3 components. Their properties in the antiferroelectric phase (T <83 K) are explained by an internal Stark effect due to the local electric field. The single emission band has a decay time of 21.5 ns at 4.5 K

Banana cultivar distribution in Rwanda

Rwanda is part of the East African plateau where banana (Musa spp.) reach their greatest importance as a staple food crop, covering 23% of land and grown by 90% of households. The region is considered a secondary centre of diversity for banana and many cultivars do exist although limited information is available on the diversity andtheir distribution in the country. In the past, banana have been a highly sustainable crop in Rwanda, but with the introduction of various diseases and pests in the last 10 -20 years, production has fallen by over 40%. The objectives of this study were to (i) establish the current diversity and distribution of banana cultivars, (ii) understand factors that affect the distribution, and (iii) identify possible synonyms and material for expansion of the National Banana Germplasm Collection. A study was conducted in four major banana growing regions ofRwanda. Twelve sites and sixty farms were used in this study. A quadrat method was used to make observations and counts of cultivars grown per farm. Farmer interviews were carried out on each farm to make assessments on the distribution of cultivars. Cultivar identification was done by farmers and subsequently verified using the national banana germplasm collection database of the ISAR-Rubona Research Institute. Clone set identification was done using the Karamura classification system. The Kigali region had the highest diversity index, followedby Kibungo and Cyangugu; while Lake Kivu border region scored the lowest diversity index. Cultivar evenness also differed, with Cyangugu being the highest and Kivu Lake the lowest. There were two major banana subgroups determined at all sites, Lujugira-Mutika with 77.8% abundance and Pisang Awak with 11.9% abundance.A total of 104 cultivar names were recorded, with 53 synonyms identified for 51 cultivars. Forty cultivars belonged to Lujugira-Mutika subgroup, with ‘Intuntu’, ‘Intokatoke’, ‘Injagi’, ‘Mbwaziruma’ being the most abundant cultivars, while eleven cultivars were exotic. Gisubi (ABB), Gros Michel (AAA), and ‘Kamaramasenge’ (AAB) were the most abundant. Farms with a higher proportion of Gisubi contained fewer other cultivars. Also, new cultivars were identified and these should be added to the National Banana germplasm collection

Musa germplasm diversity status across a wide range of agro-ecological zones in Rwanda

Objectives: This study assessed the on-farm Musa germplasm diversity across different agro-ecologies of Rwanda and the socio-economic utilization options and selection practices that create/maintain this diversity on-farm.Methodology and results: A Musa germplasm diagnostic survey was carried out in 2007 in five Rwandan districts on a transect from Lake Kivu (West) to Kirehe district (East) bordering Tanzania. Across all sites, 118 farms, each having at least 50 mats were sampled for determining Musa diversity. Forty three Musa cultivars were recorded across the five districts. Higher diversity was observed in the east declining westwards to the Lake Kivu region as reflected by the number of cultivars and their relative abundance. Nearly half of the recorded cultivars had a low diversity index (Gini-Simpson 1-D &lt; 0.2) and therefore prone to genetic erosion. Cooking cultivars only dominate in the district of Kirehe, while beer cultivars dominate the banana production landscape in the other districts. Taste/flavor, bunch size and market demand were the most important criteria for banana cultivar selection and thus greatly influenced cultivar conservation and distribution on-farm. Diseases such as Fusarium wilt and Xanthomonas wilt greatly contributed to genetic erosion.Conclusion and application of results: Musa cultivar diversity in Rwanda is under threat. Ex-situ conservation of the menaced cultivars is of crucial importance. Beer cultivars dominated the landscape. Cultivar diversity on-farm was influenced by the prevailing altitude; taste/flavor, bunch size, and market demand of the cultivars; and their susceptibility to diseases especially Fusarium and Xanthomonas wilt. Banana breeding or adaptation strategies therefore should take into account the farmer preferred traits. In addition, strategies for managing these diseases are critical for preventing the genetic erosion of the affected cultivars.Keywords: cultivar evenness, cultivar richness, diversity index, genetic erosio

Musa germplasm diversity status across a wide range of agro-ecological zones in Rwanda

This study assessed the on-farm Musa germplasm diversity across different agro-ecologies of Rwanda and the socio-economic utilization options and selection practices that create/maintain this diversity on-farm. Methodology and results: A Musa germplasm diagnostic survey was carried out in 2007 in five Rwandan districts on a transect from Lake Kivu (West) to Kirehe district (East) bordering Tanzania. Across all sites, 118 farms, each having at least 50 mats were sampled for determining Musa diversity. Forty three Musa cultivars were recorded across the five districts. Higher diversity was observed in the east declining westwards to the Lake Kivu region as reflected by the number of cultivars and their relative abundance. Nearly half of the recorded cultivars had a low diversity index (Gini-Simpson 1-D < 0.2) and therefore prone to genetic erosion. Cooking cultivars only dominate in the district of Kirehe, while beer cultivars dominate the banana production landscape in the other districts. Taste/flavor, bunch size and market demand were the most important criteria for banana cultivar selection and thus greatly influenced cultivar conservation and distribution on-farm. Diseases such as Fusarium wilt and Xanthomonas wilt greatly contributed to genetic erosion. Conclusion and application of results: Musa cultivar diversity in Rwanda is under threat. Ex-situ conservation of the menaced cultivars is of crucial importance. Beer cultivars dominated the landscape. Cultivar diversity on-farm was influenced by the prevailing altitudes; taste/flavor, bunch size, and market demand of the cultivars; and their susceptibility to diseases especially Fusarium and Xanthomonas wilt. Banana breeding or adaptation strategies therefore should take into account the farmer preferred traits. In addition, strategies for managing these diseases are critical in the prevention of the genetic erosion of the affected cultivars

Comparative study on the level of bacteriological contamination of automatic teller machines, public toilets and public transport commercial motorcycle crash helmets in Kigali City, Rwanda

Background: The environments can be contaminated by infectious agents that constitute a major health hazards as sources of community and hospital-acquired infections due to various activities.Objective: A comparative study on the level of bacteriological  contamination of automatic teller machines (ATMs), public toilets and commercial motorcycle crash helmets were conducted in Kigali city during the period of January to March, 2013.Design: Samples were collected from selected ATMs, public toilets and commercial motorcycle crash helmets surfaces. Micro-organisms identified from these samples were associated to infecting organisms recovered from unwashed hands surfaces and recorded results in the nearby hospital.Setting: Samples from each device and subject were transported to the laboratory where they were analysed for the presence of coliforms and other airborne, human skin and intestinal disease causing microorganisms. Microbiological methods including spread plate techniques and some  biochemical tests were used to partially identify the microorganisms.Subjects: Subjects involved in this study were consented students from University  of Rwanda and Kigali motorcyclists for collections of samples from hands and crash helmets respectively.Results: The following pathogenic bacteria have been found on the devices, Staphylococcus aureus, Staphylococcus epidermis, Streptococcus species, Escherichia coli, Salmonella, Klebsiella, Enterobacter aerogenes, Pseudomonas. The commercial motorcycle crash helmets had the highest level of bacteriological contamination compared to ATMs and public toilets. There was no growth observed on samples collected after treatment from ATMs, public toilets, and commercial motorcycle crash helmets. Attempt to correlate this finding with infecting organisms recovered from unwashed hands surfaces and recorded results in the nearby hospital show that thepresences of some of these infectious pathogens. Conclusion: This study has revealed the ability of these public devices to serve as vehicle of transmission of microorganisms with serious health implications. To improve and ensure the safety of these public devices the use of disinfectants is of high importance on reducing bacteriological load on those public devices. Proper cleaning regimen to sanitise these facilities regularly and public education on their hygienic usage are recommended to reduce the associated risks

Optical properties of F centers in KCN crystal

Absorption, excitation and emission spectra of F centers in KCN were measured between 4.5-175 K. Due to the cubic to orthorhombic structural phase transition at 168 K, the F band splits into 3 components. Their properties in the antiferroelectric phase (T <83 K) are explained by an internal Stark effect due to the local electric field. The single emission band has a decay time of 21.5 ns at 4.5 K

Diversity and abundance of soil-litter arthropods and their relationships with soil physicochemical properties under different land uses in Rwanda

peer reviewedSoil-litter arthropods are critical for ecosystem functioning and sensitive to land use change, and hence to the variations in soil physicochemical properties. The relationships between soil-litter arthropod communities and soil physicochemical properties, however, remain poorly studied in Rwanda. We explored the relationships between the families of soil-litter arthropods and soil properties in exotic and native tree species, and in varieties of coffee and banana plantations. Soil-litter arthropods were sampled by using Berlese funnels, hand sorting, and pitfall traps, and were identified to the family level. Soil cores were collected and analysed for soil pH, available phosphorus, total nitrogen, soil organic carbon, silt, clay and sand. A total of 3176 individuals of soil-litter arthropods were collected, identified and classified into 13 orders and 23 families. Higher abundance was found in soil and litter sampled in plots of native tree species and banana plantations compared to exotic tree species and coffee plantations. Higher diversity was found in plots of native and exotic tree species. The analysis of soil physicochemical properties indicated that native tree species offer suitable conditions of studied soil properties. The study of the relationships between the land use, soil properties and families of soil-litter arthropods indicated positive correlations and relationships mainly in native tree species. We conclude that forest with native tree species play an important role in the conservation of soil-litter arthropods and for maintenance of better soil conditions

Identification of iron-manganese oxidising bacteria from urban wetland water in Kigali, Rwanda

This work was supported by SIDA grant to University of Rwanda, 2016

Parenting practices and family relationships during the COVID-19 lockdown in Ghana

The effects of the COVID-19 pandemic have been far reaching across almost every sphere of life. Families, which are the basic units of society, have not been spared the ravages of the pandemic. Changes in family daily routines as a result of COVID-19 can affect spousal relationships, parenting and childcare practices. However, the extent to which the pandemic has affected parenting practices and family relationships in Ghana is not known. The goal of this study was to assess how parenting practices and family relationships have been influenced during the COVID-19 pandemic in Ghana. Data for this paper was drawn from an online questionnaire response from 463 participants in Ghana as a subset analysis from a multi-country study on personal and family coping system with COVID-19 pandemic in the global south. The mean score for pre-COVID-19 relationship with partner (36.86) was higher (p<0.0001) than the mean score for during COVID-19 relationship with partner (35.32) indicating that COVID-19 has had negative influence on relationships. The mean score for pre-COVID-19 parenting (32.78) was higher (p<0.0001) compared to the mean score for during COVID-19 parenting (31.40) indicating negative influence on parenting. We have predicted that participants whose coping levels were “Well” on the average, are likely to be doing well in relationship with partners and parenting practices during the COVID-19 period The challenging public health containment measures of the COVID-19 pandemic have negatively influenced the relationship between partners and parenting practices in Ghana