Dwelling or duelling in possibilities: how (Ir)relevant are African feminisms?

In its four decades of rebirth, the world has debated (enough) the relevance of feminism, but there is, surprisingly, refreshingly emergent dimensions at the turn of the twenty-first century: feminisms from feminism flowing from Africa. The theories or models of Womanism, Stiwanism, Motherism, and Nego-feminism, with their underlying assumptions and values,were all born at various end times of the twentieth century with a common objective of seeking gender justice. This paper examines the crucial question of how relevant these models are to the global practice of woman as human. What propels their separateness, and why didn‘t they combine to make a more solid stance on the plight of the African woman? In fact, why can‘t they simply identify with the general feminism? Put differently, are they dwelling in the same terrain or are they separable and easily recognisable discourses duelling in possibilities for the woman in Africa in particular and the woman of the globe in general? More specifically, how (ir)relevant are African feminisms?In trying to answer these questions, the paper presents a critical review of the afore-mentioned theories of African feminisms with the goal of providing readers an understanding of what is new in each model, and what is similar or different between the various strands of African feminisms. The paper concludes with the author‘s analysis of the model that holds the best promise or possibilities for African feminism to achieve its seemingly elusive goal of gender equality

Zig-zag Sort: A Simple Deterministic Data-Oblivious Sorting Algorithm Running in O(n log n) Time

We describe and analyze Zig-zag Sort--a deterministic data-oblivious sorting algorithm running in O(n log n) time that is arguably simpler than previously known algorithms with similar properties, which are based on the AKS sorting network. Because it is data-oblivious and deterministic, Zig-zag Sort can be implemented as a simple O(n log n)-size sorting network, thereby providing a solution to an open problem posed by Incerpi and Sedgewick in 1985. In addition, Zig-zag Sort is a variant of Shellsort, and is, in fact, the first deterministic Shellsort variant running in O(n log n) time. The existence of such an algorithm was posed as an open problem by Plaxton et al. in 1992 and also by Sedgewick in 1996. More relevant for today, however, is the fact that the existence of a simple data-oblivious deterministic sorting algorithm running in O(n log n) time simplifies the inner-loop computation in several proposed oblivious-RAM simulation methods (which utilize AKS sorting networks), and this, in turn, implies simplified mechanisms for privacy-preserving data outsourcing in several cloud computing applications. We provide both constructive and non-constructive implementations of Zig-zag Sort, based on the existence of a circuit known as an epsilon-halver, such that the constant factors in our constructive implementations are orders of magnitude smaller than those for constructive variants of the AKS sorting network, which are also based on the use of epsilon-halvers.Comment: Appearing in ACM Symp. on Theory of Computing (STOC) 201

Final state interactions in two-particle interferometry

We reconsider the influence of two-particle final state interactions (FSI) on two-particle Bose-Einstein interferometry. We concentrate in particular on the problem of particle emission at different times. Assuming chaoticity of the source, we derive a new general expression for the symmetrized two-particle cross section. We discuss the approximations needed to derive from the general result the Koonin-Pratt formula. Introducing a less stringent version of the so-called smoothness approximation we also derive a more accurate formula. It can be implemented into classical event generators and allows to calculate FSI corrected two-particle correlation functions via modified Bose-Einstein "weights".Comment: 12 pages RevTeX, 2 ps-figures included, submitted to Phys. Rev.

INTERPRETING THE 3D ORIENTATION OF VASCULAR CANALS IN CORTICAL BONE IN BIRDS AND BATS

Vascular canals in cortical bone during growth and development typically show an anisotropic pattern with canals falling into three main categories: circumferential, radial, and longitudinal. Two major hypotheses attempt to explain the preferred orientations in bone: that vascular canal orientation is optimized to resist a predominant strain direction from functional loading, or that it reflects growth requirements and velocity. This thesis presents a novel method to measure the three dimensional (3D) orientation of vascular canals. Image data are obtained from micro-CT scans and two angles are measured: phi, determining how longitudinal a canal is; and theta, determining whether a canal is radial or circumferential. This method offers a direct (3D) method for quantifying features of canal orientation and can be applied easily and non-destructively to multiple species and bones. This thesis describes two major studies to examine the orientation of vascular canals in birds and bats, the two extant groups of flying vertebrates. The first study examined the vascular canal network in the humerus and femur of a comparative sample of 31 bird and 24 bat species to look for a connection between canal orientation and functional loading. In addition to canal orientation several cross-sectional geometric parameters and strength indices were measured. The results indicated that the bat cortices are relatively thicker and poorly vascularized, whereas those of birds are thinner and more highly vascularized, and that bird bones have a greater resistance to torsional stress than the bats; in particular, the humerus in birds is more adapted to resist torsional stresses than the femur. Our results show that birds have a significantly higher laminarity index than bats. Counter to expectation, the birds had a significantly higher laminarity index in the femur than in the humerus. We conducted a comparison between our 3D method and an analogue to 2D histological measurements. This comparison revealed that 2D methods significantly underestimate the amount of longitudinal canals by an average of 20% and significantly overestimate the laminarity index by an average of 7.7%, systematically mis-estimating indices of vascular canal orientations. The second study was a controlled growth experiment using broiler chickens to investigate the effect of growth rate on vascular canal orientation. Using feed restriction we set up a fast growing control group and a slow growing restricted group. We found consistent patterns in the comparison between the humerus and the femur in both groups, with the humerus having higher laminar and longitudinal indices and a lower radial index than the femur. The faster growing group had higher radial indices and lower laminar and longitudinal indices in both the humerus and the femur than the restricted group. The higher radial indices in our control group point to a link between radial canals and faster growth, and laminar canals and slower growth, while the higher laminar indices in the humerus contradict the results of the first study and point to a link between circumferential canals and torsional loading. We believe this difference is due to differences in femoral loading between chickens and other birds. Overall our results indicate that the orientation of the cortical canal network in a bone is the consequence of a complex interaction between that bone’s growth rate and functional loading environment

Comment on "Canonical and Mircocanonical Calculations for Fermi Systems"

In the context of nuclear physics Pratt recently investigated noninteracting Fermi systems described by the microcanonical and canonical ensemble. As will be shown his discussion of the model of equally spaced levels contains a flaw and a statement which is at least confusing.Comment: Comment on S. Pratt, Phys. Rev. Lett. 84, 4255 (2000) and nucl-th/990505

Effects of Nutrients on Productivity and Morphology of Typha angustifolia x latifolia

The productivity of natural stands of cattails (Typha latifolia) has been correlated with the amounts of nutrients in the soil and water by Boyd and Hess (Ecology, 51: 296, 1970). The direct effects of varying levels of nitrogen (N), phosphorus (P) and potassium (K) on productivity were examined in our study by growing cattails in Hoagland\u27s nutrient solution. Concentrations of ¼, 1/16, and 1/64 the amount of N present in complete Hoagland\u27s solution (0.01Ml resulted in 63 percent, 48 percent and 26 percent of the dry weight of plants grown in complete solution. Rhizomes used to start plants contained considerable amounts of P and K since growth in solutions with no P or no K resulted in dry weights up to 37 percent of that of plants grown in complete solution. Nutrient availability also affected plant morphology . Reduced N increased root growth up to 75 percent greater than that of plants grown in complete solution

Optimal Tableaux Method for Constructive Satisfiability Testing and Model Synthesis in the Alternating-time Temporal Logic ATL+

We develop a sound, complete and practically implementable tableaux-based decision method for constructive satisfiability testing and model synthesis in the fragment ATL+ of the full Alternating time temporal logic ATL*. The method extends in an essential way a previously developed tableaux-based decision method for ATL and works in 2EXPTIME, which is the optimal worst case complexity of the satisfiability problem for ATL+ . We also discuss how suitable parametrizations and syntactic restrictions on the class of input ATL+ formulae can reduce the complexity of the satisfiability problem.Comment: 45 page