Blood Press ure of Baka Pygmies Living in Southeastern Cameroon

African hunter-gatherers, Baka Pygmies (N = 276, ≥ 17 years of age) from the southeastern part of Cameroon participated in an assessment study of their blood pressure (BP) measurements. For comparison, data from 2 different Japanese populations (H with n = 632, and Y with n = 131 groups) were used. T here were no differences in systolic/diastolic BP in the Baka Pygmies with respect to the sex. A comparison of BP showed that neither systolic nor diastolic BP increased with age in Baka Pygmies, but it increased in the Y group (from 20 to 60 years). The average systolic/diastolic BP in Baka Pygmies (122.8 ± 10.9/71.2 ± 8.6 mmHg) was significantly lower than that of the H and the Y groups (126.1 ± 17.5/80.3 ± 11.3 and 131.6 ± 15.4/78.8 ± 9.9 mmHg, respectively). Most of the systolic and diastolic BP measurements in the H and the Y groups were classified high-normal or Grade 1 hypertension, whereas BP of most Baka Pygmies were classified as normal or optimal. These results revealed that an average BP of approximately 120/70 mmHg did not increase with age in Baka Pygmies living in the rainforest hunting and gathering for their living

Interactions of fragment ions of tetradecane with solid surfaces

Vapors of tetradecane (C[14]H[30]) were ionized by electron bombardment. The generated fragment ions such as C[3]H[7], C[6]H[13], and C[12]H[25] ions were separated by an E × B filter (Wien filter) and accelerated toward Si(1 0 0) substrates. Thickness measurements showed that thin films were deposited on the Si substrates by C[3]H[7]- and C[6]H[13]-ion irradiation, although the Si substrate surface was predominantly sputtered by C[12]H[25] ions. Rutherford backscattering spectroscopy showed that the irradiation damage by the fragment-ion beams decreased with the increasing molecular weight of the fragment ions at the same acceleration voltage. Furthermore, Raman spectra as well as X-ray photoelectron spectroscopy measurements showed that DLC films were formed by C[3]H[7]- and C[6]H[13]-ion irradiation with the film thickness being larger in case of C[3]H[7]. On the contrary, for C[12]H[25]-ion irradiation, chemical sputtering occurred by surface reactions of hydrogen and methyl radicals with silicon atoms. The chemical reaction at the irradiated substrate surface could be enhanced by the higher temperatures achieved by the high energy–density irradiation effect of the polyatomic ions

A controlled foraging trip in a communal forest of southeastern Cameroon

Since 1995, we have been researching the "Wild Yam Question, " that is, whether or not human beings could live without agricultural products in tropical rainforests. We conducted surveys of the distribution and reserves of yam and yam-like plants and observational surveys of 3 controlled foraging trips, during which the cooperators of the Baka hunter-gatherers could use no agricultural products, in the Ndongo area and showed the possibility human beings be able to live without agricultural products and the high reliability of yam tubers to a foraging life in the tropical rainforest of southeastern Cameroon. But there still remain some issues to be examined. Our 2 controlled foraging trips were done in a forest area which local people rarely visited and was likely to be rich in wild food resources, and the third trip was done in a forest area which they often entered to set snares and was likely to be poor in wild food resources. How does the foraging life style differ between these 2 types of forest? Furthermore, in the previous 2 controlled foraging trips the Baka cooperators used wire-snares, but did not use them on the latest trip as such durable and labor-saving wire-snares would not have been available to Stone Age hunter-gatherers. What difference does the presence or absence of wire-snares make to the foraging life style in tropical rainforests? Based on this survey of a controlled foraging trip in a communal forest which local people communally managed and exploited, we demonstrated that (1) supplying a comparable amount of food to that in remote forests rich in wild food resources, yam tubers remained a staple food for forest foragers even in a communal forest, (2) the present Baka could obtain few game animals without the use of wire snares in the communal forest, (3) game animals, like yam tubers, are a critical food for the foraging lifestyle in southeastern Cameroon forests as their scarcity has a notable impact not only on the hunter-gatherers nutritional intake but also on their emotional state