Umma Staff Publications

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Author: search.filters.author.Abdillahi, Halima SaadoHas files: Yes

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    Towards drought impact-based forecasting in a multi-hazard context
    (Elsevier, 2022-01-26) Boult, Victoria L.; Black, Emily; Abdillahi, Halima Saado; Bailey, Meghan; Harris, Clare; Kilavi, Mary; Kniveton, Dominic; MacLeod, David; Mwangi, Emmah; Otieno, George; Rees, Elizabeth; Rowhani, Pedram; Taylor, Olivia; Todd, Martin C.
    The lives and livelihoods of people around the world are increasingly threatened by climate related risks as climate change increases the frequency and severity of high-impact weather. In turn, the risk of multiple hazards occurring simultaneously grows and compound impacts become more likely. The World Meteorological Organization (WMO) proposed the use of multi-hazard impact-based forecasting (IbF) to better anticipate and reduce the impacts of concurrent hazards, but as yet, there are few operational examples in the humanitarian sector. Drought is particularly susceptible to multi-hazard influences. However, challenges encountered in the development of drought IbF systems – including poor understanding of compound impacts and specific hazard-focused mandates – raise important questions for the feasibility of multi-hazard IbF as envisioned by the WMO. With these challenges in mind, we propose an interim approach in which real-time assessment of dynamic vulnerability provides a context for drought-based IbF. The incorporation of dynamic vulnerability indicators account for the local effects of non-drought hazards, whilst the use of a drought-based system facilitates effective intervention. The proposed approach will improve our understanding of compound events, enhance adoption of IbF in the humanitarian sector, and better mitigate the impacts of concurrent hazards.
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    Effect of Disturbance On the Population Structure and Regeneration of Trees: A Case Study of Acacia xanthophloea (Benth) Woodland in Ol-Pejeta Conservancy in Kenya
    (International Journal of Science and Research (IJSR), 2018-03) Muhati, Godwin Leslie; Abdillahi, Halima Saado
    Tree damage was assessed in 1540 Acacia species (A. xanthophloea) in Olpejeta Conservancy. Using belt transects measuring (20 x 50 m), trees in the sample sites (closed and open) were counted. Measurements were made of Acacia tree count, recruits count, diameter at breast height, and mortality for both adult trees and seedlings. Densities were significantly higher in enclosed areas (398.3 ± 16.60 trees/ha) than open areas (243.3 ± 10.13) trees/ha. Elephants recorded the highest damage to the sampled trees with 54.55% damage while human beings caused 12.85% of the damage. Browsing was the main form of damage in open areas. Mean height for enclosed and open sites was 3.77 ± 4.61 and 5.35 ± 8.81, respectively. These findings suggest that herbivory damage did not have a significant effect on seedling regeneration but rather had an effect on population structure. Debarking caused by elephants occurred in the open areas with the highest being 96% of the sampled trees in the 11-25% damage class. The diameter class quotients fluctuated, an indication of the unstable population thus suggesting the impact of herbivory on population structure. Key recommendations include the creation of more enclosure zones, winning back more space by controlling the densities of browsers, long-term monitoring and the promotion of recruitment and regeneration rather than reducing mature tree loss.
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    Determinants of Household Willingness to Pay for Improved Water Supply: A Case Study of Baringo and Samburu Counties, Kenya
    (Researchgate, 2020-09) Kingori, Sarah; Abdillahi, Halima Saado
    Background: In Sub-Saharan Africa, the supply of affordable, accessible and safe drinking water particularly in rural areas lags behind global progress. Achieving the universal and equitable access objectives warrants an understanding of household behavior in relation to water services. Purpose of the study: The aim of the study was to investigate the factors that influence willingness to pay for improved water service provision in a rural context in Kenya. Methods: A total of 601 households in Baringo and Samburu Counties were randomly selected using probability proportional to size technique. The data was analyzed using descriptive statistics and logit regression. Results: The empirical result shows that demographic characteristics of household, water source, quality and quantity, children responsible for fetching water, water access challenges and frequency of diarrhea are significant variables that explain willingness to pay. Conclusion: The findings conclude with important policy recommendations; (i) demand-driven approaches in the design of water supply projects, (ii) enhanced water quality management, and (iii) awareness creation to achieve social and health benefits which can facilitate long-term access and sustainability.
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    Anti-inflammatory, antioxidant,anti-tyrosinase and phenolic contents off our Podocarpus species used in traditional medicine in South Africa
    (Elsevier Ireland, 2010-07-06) Abdillahi, Halima Saado; Finnie, J.F.; Staden, J.Van
    Ethnopharmacological relevance: Species of Podocarpus are used traditionally in their native areas for the treatment of fevers,asthma,coughs,cholera,chest complaints,arthritis,rheumatism,venereal diseases and distemper in dogs. Aims of the study: To investigate the antioxidant,anti-inflammatory and anti-tyrosinase activities off our Podocarpus species, Podocarpus elongatus, Podocarpus falcatus, Podocarpus henkelii and Podocarpus lati-folius, used in traditional medicine in South Africa. Phytochemical analysis to determine the phenolic contents was also carried out. Materials and methods: DPPH, FRAPand -carotene-linoleic acid assays were used to determine the antioxidant/radical scavenging activities of these species. Anti-inflammatory activity of these species was assayed against two cyclooxygenase enzymes(COX-1 and COX-2).Tyrosinase inhibition activity was analysed using the modified dopachrome method with l-DOPA as the substrate. Phenolics were quantitatively determined using spectrophotometric methods. Results: Stems of Podocarpus latifolius exhibited thelowestEC50 (0.84 g/ml) inhibition against DPPH.The percentage antioxidant activity based on the bleaching rate of -carotene rangedfrom96%to99%.High ferric reducing power was observed in all the extracts.For COX-1,the lowest EC50 value was exhibited by stem extracts of Podocarpus elongatus (5.02 g/ml) and leaf extract of Podocarpus latifolius showed the lowest EC50 against COX-2(5.13 g/ml). All extracts inhibited tyrosinase activity in a dose-dependent manner with stem extract of Podocarpus elongatus being the most potent with an EC50 value of 0.14mg/ml. The total phenolic content ranged from 2.38 to 6.94 mg of GAE/g dry sample. Conclusion: The significant pharmacological activities observed support the use of these species in traditional medicine and may also be candidates in the search for modern pharmaceuticals in medicine, food and cosmetic industries.
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    Use of Geo-Information Tools to Investigate Flood Risk: A Case Study of Kwale County
    (International Center for Humanitarian Affairs, 2020) Makena, Betty; Osunga, Michael; King'ori, Sarah; Abdillahi, Halima Saado
    Five years since the adoption of the Sendai Framework for Disaster Risk Reduction 2015-2030, the concept of building resilience amongst communities to flooding is still a major concern in developing countries. This is evident from the ever-increasing flood events across Kenya and the inability of communities affected by floods to act appropriately prior to a flood event. Kwale County, in Kenya, the example of this study typifies this situation. Kenya Red Cross Society implemented a project whose goal was to strengthen institutional and community capacity in anticipatory flood risk management. The project employed the early warning services (EWS) model in understanding knowledge of flood risks. To investigate flood risk in Kwale County, openly available geo-information tools were used in systematic collection of information to understand areas exposed to floods, the communities affected and impacts they experience. These tools included; the Height Above Nearest Drainage (HAND) that identified flood prone areas and dwellings at risk of flooding from satellite imagery analysis. Open Street Map Automated Navigation Directions (OsmAnd) mobile navigation system that geo-located dwellings at risk of flooding and Kobo that collected geo-tagged data to validate inhabited buildings as to whether they are at risk of flooding. The results showed that, HAND technique identified dwellings at risk of flooding with 89% accuracy. Geo-location using OsmAnd showed that most houses identified to be at risk of flooding were falling within a circle with a radius of 5 meters. The results also show that the majority of the study area is characterized by moderate to very high flood hazard risks; 16% characterized by very high flood hazard risk, while 26% are at medium risk of flooding. This study demonstrates that HAND is a reliable tool for identification of houses at risk of flooding. The county government of Kwale and other acting institutions should endeavor in the use of these geo-information tools in investigating flood risk. Information obtained from these tools will enable such institutions to understand flood prone areas and communities at high risk of floods for better prioritization of early warning system needs and in guiding flood preparedness and early response activities.
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    Use of earth observation products to enhance humanitarian disaster response: A Case Study of KRCS Response to West Pokot Mudslides in 2019
    (Researchgate, 2020-12-01) Osunga, Michael; Makena, Betty; Abdillahi, Halima Saado
    Kenya is mostly affected by mudslides and floods during two rainfall seasons, namely March-April-May (MAM) and October-November-December (OND). These landslides, floods and mudslides more often than not lead to loss of human lives, destruction of houses, displacement of people, livestock deaths, loss livelihoods among other impacts. This paper highlights the use of earth observation satellite imageries from the Airbus foundation for-disaster impact assessment during the 2019 OND rainfall season to support effective response. On the 23rd of November 2019 during the OND rainfall season, mudslides and floods occurred in West Pokot resulting in disruption of road accessibility, loss of human lives, loss of livelihoods, houses destruction and displacement of people. Due to continuation of rainfall, roads were cut-off and hence it was difficult to access the area to determine the damage and the number of households affected. Through the partnership with Airbus foundation, International Center for Humanitarian Affairs (ICHA) at Kenya Red Cross Society (KRCS) tasked the Pleiades satellite to acquire imageries of the affected areas five days after the mudslide event. A spot 6 imagery archive captured on the 15th of May 2019 (months before the mudslide event) was downloaded from the Airbus foundation archives. A comparison of these two imageries through change detection was done in order to extract mudslide and flooding hazard extents. A hazard exposure analysis was done in order to determine houses and roads affected by the mudslide and flood hazard. Results from exposure analysis revealed over 145 houses as being destroyed and over 2.1 kilometers of roads being cut-off. Further analysis was done to determine partially and completely destroyed houses. KRCS was able to use this information for post-disaster recovery interventions such as search and rescue as well as shelter initiation of re-construction houses that were completely damaged by floods and mudslides. This study has demonstrated the valuable use of satellite imageries from the Airbus Foundation to KRCS through provision of timely and accurate information on impacts of mudslides and floods in remote and inaccessible areas in a cost-effective manner and further support effective and efficient response and recovery. It is highly recommended for KRCS and other Red Cross and Red Crescent National Societies to use earth observation satellites for post-disaster assessment especially in remote areas that are inaccessible. This by far would improve their humanitarian capacity in conducting post-disaster assessments in a cost-effective and timely manner.
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    Mutagenicity, antimutagenicity and cytotoxicity evaluation of South African Podocarpus species
    (Elsevier, 2011-12-01) Abdillahi, Halima Saado
    Ethnopharmacological relevance: Four species of Podocarpus are used in traditional medicine both in human and animal healthcare in South Africa. In vitro pharmacological screening of leaf and stem extracts of these species exhibited potent antimicrobial, anti-inflammatory, anti-tyrosinase, anthelmintic, acetyl-cholinesterase inhibitory and antioxidant activities. Aim of the study: To investigate the mutagenicity, antimutagenicity and cytotoxicity effects of leaf and stem extract of South African Podocarpus species. Material and methods: The mutagenicity and cytotoxic effects of extracts from four species of Podocar-pus were tested using the Salmonella/microsome assay with and without metabolic activation, based on the plate-incorporation method and neutral red uptake (NRU) assay respectively. Five Salmonellatyphimurium tester strains; TA98, TA100, TA102, TA1535 and TA1537 were used for mutagenicity test- ing. The relative cytotoxicity of the extracts was assessed by determining their NI50 values (50% inhibition of NRU). Results: The extracts did not show any mutagenic effects against all the tester strains with or without metabolic activation. All extracts demonstrated a strong antimutagenic effect on the mutations induced by 4NQO, decreasing its mutagenic effect in a dose-dependent manner. Strong cytotoxic effects were exhibited by petroleum ether extracts as compared to 80% ethanol extracts. When HepG2 cells were in contact with plant extracts in an increasing concentration, slopes of NRU decreased (highest–lowest %) following a concentration-dependent pattern. For 80% ethanol extracts, the most toxic extract in terms of percentage viability was leaves of Podocarpus falcatus whereby at 0.2 mg/ml, the viability of the cells was38.9%. Stem extract of Podocarpus latifolius was the most toxic among PE extracts, giving a percentage viability of 46.4 at 0.1 mg/ml. Conclusion: Absence of mutagenicity does not indicate lack of toxicity, as was observed from these extracts. These findings will help in assessing the safety measures to be considered in the use of these species and also the need to determine the cytotoxic potential of these species against various forms of human cancer cells.