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Dissertation
Indigenous knowledge and non-food uses of stingless bees honey: a comparative Study in Kenya
Authors: --- --- --- ---
Year: 2022 Publisher: Liège Université de Liège (ULiège)

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Abstract

Stingless bee (tribe Meliponini) are highly eusocial wild bee species found nowhere outside tropical and subtropical regions. Much like Apis mellifera, the Western honey bee, they produce honey whose properties are well known by local communities. Research on stingless bees has so far been mainly concentrated in South America. There is a general lack of documentation on the properties of African stingless bees honeys and on the indigenous knowledge on their uses in Africa. To contribute to filling in this knowledge gap, we conducted 68 semi-structured interviews, with the help of a questionnaire, in two Counties of Kenya: Taita Taveta and Kakamega. 
Our results indicate that interviewees keep stingless bees for food, medicine and income provision. The meanings of the local names given to the species provide information regarding the uses, the nesting habitats/substrates, as well as morphological traits of the bees. Hunting wild colonies is still commonly practiced despite the development of colony division as a means to avoid the recurrent exploitation of wild nests. This is the result of strong cultural habits, i.e. a path dependency.
We also report that stingless bee honeys play a major role in people’s nutrition, health, and in local traditions in both study locations, although they appeared to have much stronger cultural importance in Kakamega. The general observation in Taita is that interviewees do not distinguish between the uses (18 identified) of honeys of different species (Hypotrigona sp. and Liotrigona sp., both called “mbuche” in the local language). By contrast, the Kakamega interviewees recognized different species (7 identified in the area), have more specific uses (26 identified) and distinguish the properties of the honeys of each species. In both locations, the main non-food uses are: as a preventive medicine, as a decongestant, to heal the skin, to treat colds/cough. In Taita, honeys are also commonly brewed to produce a local beverage. In Kakamega, deeper cultural roots revealed that the honeys are used in more specific ways: as an aphrodisiac (M. ferruginea), to treat all kind of stomach aches: deworming, period pain, diarrhoea (M. togoensis), and in circumcision ceremonies (M.lendliana). This also applies to the largest species, M. bocandei, whose honey is often a major source of the non-food uses described above.
Our study documents for the first time the non-food uses of Afrotropical stingless bee honeys in different contexts, not only in terms of environmental conditions, but also in heritage of traditions. Meliponiculture has great potential to contribute to Kenya’s rural development, as well as food security, while conserving biodiversity. It is essential to protect and document indigenous knowledge regarding traditional uses of stingless bees honey.


Dissertation
Astrochemical pathways for the synthesis of amino-acids in interstellar clouds
Authors: --- --- --- ---
Year: 2023 Publisher: Liège Université de Liège (ULiège)

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Abstract

There is much evidence to support the exogeneous origin of amino acids on Earth. For instance, one may cite the identification of amino acids in meteoritic samples with isotopic ratios pointing towards a non-terrestrial origin, the enantiomeric excess found in the Murchison meteorite in the same direction as the homochirality problem found on Earth, or the detection of glycine in the coma of comet Churyumov-Gerasimenko and some of its likely precursors in the Interstellar Medium (ISM). However, if we adopt an exogeneous point of view, one can wonder if these amino acids are formed in the initial molecular cloud, during the formation of the solar system in a cold region of the protoplanetary disk, due to a modification due to a perturbation, or via processing within the parent-body.
To achieve a deeper insight into this issue, this master thesis focuses on a hypothetical formation of glycine in dense molecular clouds. After a deep bibliographic analysis of the many proposed mechanisms and a selection of the most relevant ones to be considered in Chapter 1, the gas-phase Astrochem code has been used. Its basic functionalities have been explained in Chapter 2. Starting from this modelling tool, the most likely precursors of glycine in a pure gas-phase context have been deeply investigated in Chapter 3 in which we have inferred the relative temporal evolution of the abundances and studied their major contributing paths. This has allowed us to deeply discuss the potential of these routes in such a medium. Moreover, we have been able to compare our results with earlier studies, in which much simpler astrochemical networks have been used. The results for the most abundant molecular species present a good match with respect to previous studies, but do not when more complex species are considered. Finally, in Chapter 4, we have focused on potential network extensions, that are based on our results and discussions in the previous chapter and on theoretical considerations.
In a nutshell, this study is offering a deep insight into the behaviour of the simplest precursors of the proposed/selected glycine formation pathways in a pure gas phase context.
Furthermore, this work is paving the way to direct long-term scientific perspectives, as discussed in Chapter 6. For instance, one may indeed cite the call for a much comprehensive and scientifically well funded astrochemical code, accompanied by a network based on rigorous kinetic parameters.

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