The Church of Women: Gendered Encounters between Maasai and Missionaries

The Church of Women: Gendered Encounters between Maasai and Missionaries . Dorothy L. Hodgson. Bloomington: Indiana University Press, 2005.     

Lateralized ultradian rhythms in time and space: a chronobiological field study in Kenyan Maasai.

Lateralized ultradian rhythms oscillating separately in the right and left hemispheres of the human brain can be monitored by variations in the tactile discrimination of either hand. A previous study in male German subjects has shown that the tactile error rates determined for the right and left hands oscillate with significantly different periodicities. In the present study, a group of Kenyan Maasai shepherds was tested while the subjects were leading herds on daily feeding routes. The Maasai exhibit considerable ultradian rhythms of about 2 hours in tactile error rates of either hand, but in contrast to the German subjects there is no significant difference between the right and left side. While an individual is en route, his hemispheres proceed through alternating states in matching segments of the path. Ultradian rhythms thus 'scan' not only the time of day but also the space, and might provide an intrinsic time-frame for neuronal processes of cognitive mapping.     

Caterpillars on a phytochemical landscape: The case of alfalfa and the Melissa blue butterfly

Modern metabolomic approaches that generate more comprehensive phytochemical profiles than were previously available are providing new opportunities for understanding plant‐animal interactions. Specifically, we can characterize the phytochemical landscape by asking how a larger number of individual compounds affect herbivores and how compounds covary among plants. Here we use the recent colonization of alfalfa (Medicago sativa) by the Melissa blue butterfly (Lycaeides melissa) to investigate the effects of indivdiual compounds and suites of covarying phytochemicals on caterpillar performance. We find that survival, development time, and adult weight are all associated with variation in nutrition and toxicity, including biomolecules associated with plant cell function as well as putative anti‐herbivore action. The plant‐insect interface is complex, with clusters of covarying compounds in many cases encompassing divergent effects on different aspects of caterpillar performance. Individual compounds with the strongest associations are largely specialized metabolites, including alkaloids, phenolic glycosides, and saponins. The saponins are represented in our data by more than 25 individual compounds with beneficial and detrimental effects on L. melissa caterpillars, which highlights the value of metabolomic data as opposed to approaches that rely on total concentrations within broad defensive classes.     

The influence of cultural framing on play in the trust game: a Maasai example

The effects of cultural framing on behavior in experimental games were explored with a trust game and the Maasai concept of osotua. Maasai use the term osotua to refer to gift-giving relationships based on obligation, need, respect, and restraint. In the trust game, the first player is given money and an opportunity to give any portion of it to the second player. The amount given is then multiplied by the experimenter, and the second player has an opportunity to give any amount back to the first player. Fifty trust games were played by Maasai men at a field site in north central Kenya. Half of the games were played without deliberate framing, and half were framed with the statement, “This is an osotua game.” Compared to games with no deliberate framing, those played within the osotua rhetorical frame were associated with lower transfers by both players and with lower expected returns on the part of the first players. Osotua rhetorical framing is also associated with a negative correlation between amounts given by the first player and amounts returned by the second. These results have implications both for the experimental game method and for our understanding of the relationship between culture and behavior.     

Risk-Pooling and Herd Survival: An Agent-Based Model of a Maasai Gift-Giving System

We use agent-based modeling to study osotua, a gift giving system used by the Maasai of East Africa. Osotua’s literal meaning is “umbilical cord,” but it is used metaphorically to refer to a specific type of gift-giving relationship. Osotua relationships are characterized by respect, responsibility and restraint. Osotua partners ask each other for help only if they are in need and provide help only when asked and only if they are able. We hypothesize that under the ecologically volatile conditions in which Maasai pastoralists have traditionally lived, such a system is particularly suited to risk pooling. Here we explore whether osotua increases the viability of herds by comparing herd survivorship and stability under osotua rules to a) no exchange and b) probabilistic rules for requesting and giving livestock. Results from this model suggest that this gift-giving system can dramatically increase herd longevity through a limited pooling of risk.     

香蜂花的组织培养与快速繁殖

1植物名称香蜂花(Melissa officinalis L.),又名蜜蜂花、香蜂草、柠檬薄荷等。2材料类别带腋芽的嫩茎段。3培养条件(1)芽诱导培养基:1/2MS 0.45%琼脂 3.0%蔗糖;(2)增殖培养基:MS 6-BA 0.4 mg·L~(-1)(单位下同) NAA 0.1 0.45%琼脂 3.0%蔗糖;(3)壮苗增殖培养基:MS 6-BA 0.1 NAA 0.05     

The effect of triacontanol on micropropagation of balm, Melissa officinalis L.

 Triacontanol, a long-chain primary alcohol was found to be an effective growth regulator in the micropropagation of balm, Melissa officinalis. In both the multiplication and the rooting phase, concentrations of 2, 5, 10 and 20 μg triacontanol per liter were applied. After 4 weeks of culture, the fresh weight of shoots was measured in the multiplication phase and root formation, photosynthetic activity, chlorophyll content and the fresh and dry weights of shoots were analyzed in the root induction phase. In the multiplication phase, 5 μg/l triacontanol was found to be the optimal concentration, while in the rooting phase 2 μg/l was the most effective. Triacontanol increased the number and length of roots, and it enhanced shoot growth, fresh weight, and the chlorophyll content, but it had no effect on the dry weight and the photosynthetic activity of the plants. Results of our work demonstrate that triacontanol can be applied as an effective growth regulator in the tissue culture of balm. Received: 3 December 1997 / Revised: 24 February 1998 / Accepted: 26 February 1999