Tectonics, volcanism, landscape structure and human evolution in the African Rift

Tectonic movements and volcanism in the African Rift have usually been considered of relevance to human evolution only at very large geographical and chronological scales, principally in relation to longterm topographic and climatic variation at the continental scale. At the more loca1 scale of catchment basins and individual sites, tectonic features are generally considered to be at worst disruptive and at best incidental features enhancing the preservation and exposure of early sites. We demonstrate that recent lava flows and fault scarps in a tectonically active region create a distinctive landscape structure with a complex and highly differentiated topography of enclosures, barriers and fertile basins. This landscape structure has an important potential impact on the co-evolution of prey-predator interactions and on interspecific relationships more generally. In particular, we suggest that it would have offered unique opportunities for the development of a hominid niche characterised by bipedalism, meat-eating and stone tool use. These landscape features are best appreciated by looking at areas which today have rapid rates of tectonic movement and frequent volcanic activity, as in eastern Afar and Djibouti. These provide a better analogy for the Plio-Pleistocene environments occupied by early hominids than the present-day landscapes where their fossil remains and artefacts have been discovered. The latter areas are now less active than was the case when the sites were formed. They have also been radically transfomed by ongoing geomorphological processes in the intervening millennia. Thus, previous attempts to reconstruct the local landscape setting adjacent to these early hominid sites necessarily rely on limited geological windows into the ancient land surface and thus tend to filter out small-scale topographic detail because it cannot be reliably identified. It is precisely this local detail that we consider to be of importance in understanding the environmental contribution to co-evolutionary developments

Lagrangian description of world-line deviations

We introduce a Lagrangian which can be varied to give both the equation of motion and world-line deviations of spinning particles simultaneously.Comment: to appear in IJT

Direct and alignment-insensitive measurement of cantilever curvature

We analytically derive and experimentally demonstrate a method for the simultaneous measurement of deflection for large arrays of cantilevers. The Fresnel diffraction patterns of a cantilever independently reveals tilt, curvature, cubic and higher order bending of the cantilever. It provides a calibrated absolute measurement of the polynomial coefficients describing the cantilever shape, without careful alignment and could be applied to several cantilevers simultaneously with no added complexity. We show that the method is easily implemented, works in both liquid mediums and in air, for a broad range of displacements and is especially suited to the requirements for multi-marker biosensors.Comment: 5 Pages, 4 figures, letter forma

General relativistic spinning fluids with a modified projection tensor

An energy-momentum tensor for general relativistic spinning fluids compatible with Tulczyjew-type supplementary condition is derived from the variation of a general Lagrangian with unspecified explicit form. This tensor is the sum of a term containing the Belinfante-Rosenfeld tensor and a modified perfect-fluid energy-momentum tensor in which the four-velocity is replaced by a unit four-vector in the direction of fluid momentum. The equations of motion are obtained and it is shown that they admit a Friedmann-Robertson-Walker space-time as a solution.Comment: Submitted to General Relativity and Gravitatio

Free clinics in the United States : an exploratory review

Free clinics are spread across the nation and serve millions of the poor and uninsured in our communities. As these clinics strive to provide quality care for their patients who have fallen through the cracks of the health care system they face many issues. The purpose of this paper was to use previous research and literature to develop a better understanding of free clinics as a collective whole with hopes of learning more about the issues they face in the process. By showing how clinics are organized and funded, what types of patients they see for what reason, and how they are staffed with medical professionals, it can be seen how they work and what purpose they serve.Honors CollegeThesis (B.?.

Open and Closed Loop Stability of Hingeless Rotor Helicopter Air and Ground Resonance

The air and ground resonance instabilities of hingeless rotor helicopters are examined on a relatively broad parametric basis including the effects of blade tuning, virtual hinge locations, and blade hysteresis damping, as well as size and scale effects in the gross weight range from 5,000 to 48,000 pounds. A special case of a 72,000 pound helicopter air resonance instability is also included. The study shows that nominal to moderate and readily achieved levels of blade inertial hysteresis damping in conjunction with a variety of tuning and/or feedback conditions are highly effective in dealing with these instabilities. Tip weights and reductions in pre-coning angles are also shown to be effective means for improving the air resonance instability

Logos and Psyche in Plato\u27s Phaedo

In this dissertation I argue that, according to the Phaedo, the ψυχή should not be understood as a reified, quasi-physical entity which can travel to another τόπος upon separation from the body; that is, the soul should not be understood as what came to be called a “spiritual substance.” Rather, I will show that the Phaedo presents the proper ontology of the soul to be based in an understanding of its characteristic activity. I will argue that this activity is revealed to be the gathering of multiplicities (‘parts’) into the intelligible unities (‘wholes’) which we experience. This gathering occurs in accord with the λόγοι in which the soul has been educated; that is, it is on the basis of our παιδεία that we gather the ‘many’ of bare perceptual experience into the meaningful ‘ones’ of our world. Attention to this characteristic ἔργον constitutes the root of virtue. Attending to this activity will reveal that, initially and for the most part, humans find themselves in a state of internal multiplicity, conflict, and cognitive dissonance. This internal dissent is not to be ultimately explained with reference to ‘parts’ of the soul. I will argue that the Phaedo reveals this internal multiplicity to be far greater than a ‘tri-partite’ theory can explain. Rather, we need to attend to the disharmonious nature of the λόγοι to which we adhere, and through which we gather the world into an intelligible order such that we are called to act. Ethical responsiveness to the world will be shown to be rooted in ontology. That is, it is in light of the way the world appears to us as a meaningful environment that we are called to act and respond ethically. When this world is fractured by internal dissent – that is, specifically, by conflicting opinions within the soul as to what is best – ethical action becomes difficult, and self-mastery is necessary. This self-mastery, however, is only necessary in the absence of internal harmony; when the self has undergone a process of gathering itself to itself – into a unified whole oriented toward the good – the soul as a unity is drawn toward the good, akrasia appears impossible, and the violence of self-mastery becomes unnecessary. The first step in the development of this harmony is a recognition of the essential, defining activity of the ψυχή. Only on this basis is it possible to ‘care for the soul.’ This basic ontology of the ψυχή must first be understood; the centrality of the condition of the soul to the way we experience the world must be recognized. On this basis we can begin to examine the λόγοι through which we gather the world, and our own selves, into intelligible unity; only then can we begin the difficult process of developing a harmony in these λόγοι which can give rise to unified, ethically and rationally directed actions and responsiveness to the world. The initial step in the development of the defining human ἀρετή is turning the soul toward itself. The development of this ontology, self-knowledge, and harmony of the self is the essential defining work of the philosopher; it is only on the basis of this proper ontology of the soul, and subsequent development of self-understanding, that care of the self can be grounded. That is: In order to know the self, it is essential to understand the nature of the ψυχή; to understand the nature of the ψυχή, it is essential to understand its defining activity. The development of excellence (ἀρετή) of the soul is rooted in a proper understanding of this ἔργον