Browsing by Author "Nyaga, Justine M."
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Anti-inflammatory norhopanes from the root bark of Fagaropsis angolensis (Engl.) H.M.Gardner
Nyaga, Justine M.; Mukavia, Justus; Omosa, Leonidah Kerubo; Ngnitedemb, Vaderament Nchiozem; Omoled, Ruth; Bitchagnoc, Gabin Thierry M.; Spitellere, Michael (Elsevier, 2020-06-17)Two new norhopane derivatives namely 3β,6β,22-trihydroxy-7β,11α-di[(4-hydroxybenzoyl)oxy]-21αH-24- norhopa-4(23)-ene (1) and 3β,6β,22-trihydroxy-7β-[(4-hydroxybenzoyl)oxy]-21αH-24-norhopa-4(23)-ene (2) together with two ... -
The Contribution of Occult Precipitation to Nutrient Deposition on the West Coast of South Africa
Nyaga, Justine M.; Neff, Jason C.; Cramer, Michael D. (2015-05-27)The Strandveld mediterranean-ecosystem of the west coast of South Africa supports floristically diverse vegetation growing on mostly nutrient-poor aeolian sands and extending from the Atlantic Ocean tens of kilometers ... -
The Contribution of Occult Precipitation to Nutrient Deposition on the West Coast of South Africa
Nyaga, Justine M.; Neff, Jason C.; Cramer, Michael D. (2015-05)The Strandveld mediterranean-ecosystem of the west coast of South Africa supports floristically diverse vegetation growing on mostly nutrient-poor aeolian sands and extending from the Atlantic Ocean tens of kilometers ... -
Do afroalpine plants differ from other alpine plants by their leaf functional traits?
Onipchenko, Vladimir G.; Kipkeev, Aliy M.; Kopylova, Natalia A.; Nyaga, Justine M.; Elumeeva, Tatiana G.; Dudova, Ksenia V.; Akhmetzhanova, Asem A.; Tiunov, Alexei V.; Karpukhin, Mikhail M.; Makarov, Mikhail I. (UoEm, 2023-06-16)Afroalpine plants develop under specific climate with great daily fluctuations and weak seasonal dynamics of temperature. Do leaf functional traits of the plants in Mt. Kenya differ from those of temperate plants in ... -
Empirical and model derived respiration responses to climate in different soils of an arid South African ecosystem
Nyaga, Justine M. (The University of the Western Cape, 2009)This study examined the magnitude of soil CO2 efflux in an arid South African ecosystem, the flux responses as well as those of key limiting nutrients to soil temperature increases and moisture reductions consistent with ... -
Food web structure of nematode communities in irrigated rice fields
Mokuah, Dorcas; Karuri, Hannah W.; Nyaga, Justine M. (Heliyon, 2023-02)Nematodes are a key component of the soil food web and they play an important role in the provision of ecosystem services. Rice cultivation in Mwea, Kenya involves the intensive use of fertilizers and pesticides which ... -
Human-Wildlife conflicts at the interface between Mt. Kenya National Park/National Forest and small holder farming communities in Embu County
Nyaga, Justine M.; Rock, Kim; Kjellander, Petter (Swedish University of Agricultural Sciences, 2021-06)Human-wildlife conflict (HWC) is a common problem for many farming communities around protected areas like parks, reserves and forests all around the world. In Kenya where most farming occurs at smallholder levels, HWC:s ... -
In vitro anti-cancer efficacy and phyto-chemical screening of solvent extracts of Kigelia africana (Lam.) Benth
Nyaga, Justine M.; Mukavi, Justus Wambua; Mayeku, Philip Wafula; Kituyi, Sarah Naulikha (Cell press, 2021-01-25)Background and objectives: Kigelia africana is a medicinal plant growing naturally in many parts of Africa. In Kenya, a water concoction of the plant is used to treat breast and prostate cancers. Laboratory data on its ... -
Influence of drought on interactions between Rhopalosiphum padi and ground dwelling predators – A mesocosm study
Njue, Martin; Muturi, Phyllis W.; Nyaga, Justine M.; Jonsson, Mattias (Wiley, 2021-05)Climate change will lead to extreme droughts, but it is difficult to predict how this will affect crop pests. In particular, it is unclear how interactions between natural en- emies and pests will be influenced. In the ... -
International Journal of Environment and Climate Change
Nyaga, Justine M.; Nyaga, Samuel K.; Gathungu, Geofrey K.; Njeru, Jafford R. (2020-12-21)Africa is under pressure from climate stresses and is highly vulnerable to the impacts of climate change. In Kenya, agriculture is the backbone of the economy making it an important contributor to food security of rural ... -
Is leaf pubescence of Cape Proteaceae a xeromorphic or radiation-protective trait?
Skelton, R. P.; Midgley, J. J.; Nyaga, Justine M.; Johnson, S. D.; Cramer, M. D. (CSIRO Publishing, 2012-03)Although pubescence has traditionally been considered to be related to the water economy of plants, the results are ambivalent and vary between different species. We tested two contrasting hypotheses for the functional ... -
Low foristic richness of afro‐alpine vegetation of Mount Kenya is related to its small area
Nyaga, Justine M.; Onipchenko, Vladimir G.; Kopylova, Natalia A.; Kipkeev, Alii M.; Elumeeva, Tatiana G.; Azovsky, Andrei; Dudov, Sergei V. (Springer, 2019-10-29)Diversity patterns of tropical alpine vegetation is poorly studied. We estimated vascular plant floristic richness for two typical afro-alpine communities in Mount Kenya using a series of nested plots sized from 25 to 100 ... -
Nutritional contribution of atmospheric deposition to the Strandveld vegetation of West Coast South Africa
Nyaga, Justine M. (University of Cape Town, 2013-07)Ecosystem nutrient availability depends on the balance between rates of nutrient inputs and losses. Nutrients may be lost through fire and displacement of ash, herbivory, leaching and volatilization. The main pathways ... -
Precision Agriculture for Resource Use Efficiency in Smallholder Farming Systems in Sub-Saharan Africa: A Systematic Review
Nyaga, Justine M.; Onyango, Cecilia M.; Wetterlind, Johanna; Söderström, Mats; Piikki, Kristin (MDPI, 2021-01-21)Opportunities exist for adoption of precision agriculture technologies in all parts of the world. The form of precision agriculture may vary from region to region depending on technologies available, knowledge levels and ... -
Precision agriculture research in sub‑Saharan Africa countries a systematic map
Nyaga, Justine M.; Onyango, Cecilia M.; Wetterlind, Johanna; Söderström, Mats (Springer, 2021-01-15)Precision agriculture (PA) has a huge potential for growth in sub-Saharan Africa (SSA), but it faces a number of social-economic and technological challenges. This study sought to map existing PA research and application ... -
Response of Selected Kenyan Rice Cultivars to Infection by Root Knot Nematode (Meloidogyne incognita)
Nyaga, Justine M.; Namu, John; Alakonya, Amos; Karuri, Hannah; Masanga, Joel; Njeri, Editah (Springer, 2019-03-22)Meloidogyne incognita causes huge yield losses in rice which is the third most important cereal crop in Kenya. The aim of this study was to identify M. incognita-resistant rice cultivars from Kenya and relate the responses ... -
SPEI-based spatial and temporal evaluation of drought in Somalia
Nyaga, Justine M.; Musei, Sylus Kipngeno; Dubow, Abdi Zeila (Elsevier, 2020-09-06)Somalia is one of the most drought prone countries both in Africa and globally. Drought events usually develop gradually unnoticed, causing tremendous effects on both agriculture and environment. This study evaluated ... -
Temporal variation in physico-chemical characteristics, phytoplankton composition and biomass in Lake Solai, Kenya
Nyaga, Justine M.; Koskei, Eunice C.; Kotut, Kiplagat; Oduor, Steve Omondi (2019-10-20)The physico-chemical properties and phytoplankton community structure of Lake Solai were investigated between April 2018 and August 2018. Water temperature, conductivity (EC), dissolved oxygen (DO) content and pH were ... -
Value chain and sustainability of mangrove wood harvesting in Lamu, Kenya
Riungu, Purity M.; Nyaga, Justine M.; Githaiga, Michael N.; Kairo, James G. (Elsevier, 2022-08)Mangrove forests provide harvestable wood and non-wood resources to human society globally. The current study evaluated value chain of mangrove wood products from Lamu, Kenya, and how these impacts on resources’ sustainability. ... -
Vertical Distribution of Plant-Parasitic Nematodes in Sweet Potato
Kemboi, Bernard; Karuri, Hannah; Nyaga, Justine M.; Kingsbury, Aaron J. (Sciendo., 2022)Plant-parasitic nematodes (PPN) are harmful pests that have become a severe threat to crop production worldwide. Diversity of PPN at horizontal and spatial scales influence the effectiveness of control strategies. This ...