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The study of Africa has helped to further several healthy trends in the development of the discipline of political science. Confrontation with the rich variety of structural forms and modes of human expression of contemporary Africa has compelled the political analyst to look beyond the narrow “political” realm and conventional “political” structures for a more complete understanding and explanation of political phenomena. This African impact upon the discipline has come at a most propitious time—a time of intensive self-criticism from which at least three new emphases in research are beginning to emerge. One is the holistic approach reflected in efforts to classify and to compare political systems as wholes. A second approach, obviously related to the first but independently pursued by its proponents, is an ever-increasing explicit concern with non-political factors (e. g., the family, voluntary associations, the economic system, the social stratification system, cultural values, and so forth) as they may be related to and effect the political system and political behavior. Here, the impact of other disciplines, and particularly sociology, anthropology and psychology, is clearly manifest not only in the type of data gathered but in such neologisms as “political socialization” and “political acculturation.”
In this work, we conduct particle-resolved direct numerical simulations to investigate the influence of particle inertia on the settling velocity of finite-size particles at low volume fraction in homogeneous isotropic turbulence across various settling numbers. Our results for finite-size particles show only reductions of settling velocity in turbulence compared to the corresponding laminar case. Although increased particle inertia significantly reduces the lateral motion of particles and fluctuations in settling velocity, its effect on the mean settling velocity is not pronounced, except when the settling effect is strong, where increased particle inertia leads to a noticeable reduction. Mechanistically, the nonlinear drag effect, which emphasises contributions from large turbulent scales, cannot fully account for the reduction in settling velocity. The influence of small-scale turbulence, particularly through interactions with the particle boundary layer, should not be overlooked. We also analyse the dependency of turbulence’s modification on particle settling velocity within a broader parameter space, encompassing both sub-Kolmogorov point particles and finite-size particles. Additionally, we develop a qualitative model to predict whether turbulence enhances or retards the settling velocity of particles.
It is a real pleasure to introduce the impressive articles specially prepared for this issue of the Bulletin by members of the Libraries Committee of the African Studies Association. They reveal a fact already discovered by the book dealers of Europe and Africa, namely, the remarkable demand for Africana by American libraries during the past decade.
In its meetings thus far the Libraries Committee has endeavored to identify African library resources and needs in the United States. Certain of the needs we have considered are outlined on pp. 15-16 of the November, 1958 issue (Vol. I, No. II) of the Bulletin. Since that date the Committee has completed, in collaboration wiih Library of Congress officials, a detailed proposal and budget to establish an African Studies Unit in the Library of Congress which, among other duties, would produce a monthly accessions list of publications on Africa acquired by American libraries. This proposal has now been approved by the Board of Directors of the Association which is seeking the funds necessary to implement it.
Hopefully there has been enough contact between humanists and social scientists in recent years and enough attempt at creating a common concern with common problems so that the one no longer entirely distrusts the cold and myopic eye of science peering into the literary intricacies of folklore and the other no longer thinks of folklore as a kind of folk entertainment, “a floating segment of culture,” which is marginal to his main concerns. I cannot speak for the humanist, though I should imagine he has learned to put up with the sometimes heavy hand of the anthropologist or political scientist for the sake of the wealth of contextual crosscultural data he gets from him. But speaking for the anthropologist, I would be surprised if there are any of us left today who would not collect what oral narrative we could, exploiting to the fullest the potentialities of such data in arriving at explanations for the workings of society and culture. We recognize well enough that folklore functions within a social and cultural context whose cultural content and social integration it both reflects and determines; We should therefore find some agreement in regarding folklore as having efficacy in human affairs - as being an agent.
That folklore is an agent of particular vitality and potential in Africa is something that can hardly be denied by those who have been there. We have evidence for this in the many extensive collections of traditional verbal art from the different quarters of that continent, and most recently we have only to mention the Herskovits collection inDahomean Narrative. But folklore is not to be seen only as a manifestation of tribal tradition now on the wane. It must be seen as an aspect of African culture that willenjoy and suffer the greatest exploitation for the sake of the African future. This should surprise neither humanist nor social scientist for they both know well “how inviting, from its very nature the field of folklore is for those who wish to exalt national character and a national destiny.” (Herskovits, 1959: 219). We have watched it being used to these ends in countries as far removed as Ireland and Argentina, and now we see the same thing in Africa. We see, for example, how the concepts and the circumnambient mythologies of “African personality” and “negritude” depend in their expression upon authentic or reinterpreted African folklore. In the matter of migration legends alone one has only to read the work of one of the early African intellectuals to articulate these notions-Cheik Anta Diop's Nations Negres et Culture (1948)-to realize how crucial to the arguments of these cultural pan-Africanists are the migration legends of the various African peoples.
In gas evolving electrolysis, bubbles grow at electrodes due to a diffusive influx from oversaturation generated locally in the electrolyte by the electrode reaction. When considering electrodes of micrometre size resembling catalytic islands, direct numerical simulations show that bubbles may approach dynamic equilibrium states at which they neither grow nor shrink. These are found in undersaturated and saturated bulk electrolytes during both pinning and expanding wetting regimes of the bubbles. The equilibrium is based on the balance of local influx near the bubble foot and global outflux. To identify the parameter regions of bubble growth, dissolution and dynamic equilibrium by analytical means, we extend the solution of Zhang & Lohse (2023 J. Fluid Mech. vol. 975, R3) by taking into account modified gas fluxes across the bubble interface, which result from a non-uniform distribution of dissolved gas. The Damköhler numbers at equilibrium are found to range from small to intermediate values. Unlike pinned nanobubbles studied earlier, for micrometre-sized bubbles the Laplace pressure plays only a minor role. With respect to the stability of the dynamic equilibrium states, we extend the methodology of Lohse & Zhang (2015a Phys. Rev. E vol. 91, 031003(R)) by additionally taking into account the electrode reaction. Under contact line pinning, the equilibrium states are found to be stable for flat nanobubbles and for microbubbles in general. For unpinned bubbles, the equilibrium states are always stable. Finally, we draw conclusions on how to possibly enhance the efficiency of electrolysis.
The opening session was devoted to a discussion of the UNESCO Conference on the Development of Higher Education in Africa held in Tananarive, September 3-12, 1962, and its implications for the United States. Speakers on the panel were Dr. de Kiewiet; Karl Bigelow, Teachers College of Colum-gia University; Robert Van Duyn, Agency for International Development; and Kenneth Snyder, Bureau of International Educational and Cultural Affairs, U.S. Department of State. Dr. de Kiewiet, introducing the panel, paid a tribute to Dr. Ras Johnson of AID, a member of the official delegation, who lost his life while returning to the United States.
Dr. de Kiewiet remarked that, having assumed official delegations went out with highly specific instructions, he had made the reassuring discovery this was not the case. The delegation had largely determined for itself what the issues were and had developed responses to them; this flexibility had been important in establishing a successful relationship between the conference as a whole and the public and private sectors of American higher education.