Post-Newtonian gravitational radiation and equations of motion via direct integration of the relaxed Einstein equations. V. Evidence for the strong equivalence principle to second post-Newtonian order

Using post-Newtonian equations of motion for fluid bodies valid to the second post-Newtonian order, we derive the equations of motion for binary systems with finite-sized, non-spinning but arbitrarily shaped bodies. In particular we study the contributions of the internal structure of the bodies (such as self-gravity) that would diverge if the size of the bodies were to shrink to zero. Using a set of virial relations accurate to the first post-Newtonian order that reflect the stationarity of each body, and redefining the masses to include 1PN and 2PN self-gravity terms, we demonstrate the complete cancellation of a class of potentially divergent, structure-dependent terms that scale as s^{-1} and s^{-5/2}, where s is the characteristic size of the bodies. This is further evidence of the Strong Equivalence Principle, and supports the use of post-Newtonian approximations to derive equations of motion for strong-field bodies such as neutron stars and black holes. This extends earlier work done by Kopeikin.Comment: 14 pages, submitted to Phys. Rev. D; small changes to coincide with published versio

Flock leadership helps teams achieve the firm’s innovation goals

The key is for leaders to promote the right set of norms for each team's work, writes Thomas Wil

1984: the year when young Britons started to become more Europhile than their elders

Older Britons were far more likely to vote Leave than 18-24 year-olds. Will Thomas looks at attitudes to the EU since we joined in 1973. Until the mid-1980s, the young and old shared relatively similar support for the EU – but then their views began to diverge. He suggests that young people are in a better position to take advantage of the EU offers than the old are

In This Great Future, You Can't Forget Your Past

The resiliency of the memory institution is impaired by depending on public or private state power as an anchor. Evidence for this is shown in the ample traces in the archival record of the enmeshing of such Black state power as has been achieved in emancipatory or postcolonial schemes in an international system which will destroy all around it rather than dismantle the structures which maintain it, one of which structures is the subjugation of the many for the benefit of a few. The neutrality of archival practice in the service of such structures is under challenge from both a change in methods of creating and managing records relying on open formats, protocols, and algorithms and a change of industrial organization made possible by interoperable systems and inexpensive broadband networking. The nature of the state under the various revolutions of the past 500 years have changed archives as an institution and as practice; the contemporary change creates the opportunity to drive that change toward the memory commons model. This paper argues that such a drive can come through the bottom-up definition of a specific poetic counternarrative memory and defines how a commons can be built around it

Interregional Analysis of Interstate Dairy Compacts

Livestock Production/Industries, Marketing,

Enhancement and Civic Virtue

Opponents of biomedical enhancement frequently adopt what Allen Buchanan has called the “Personal Goods Assumption.” On this assumption, the benefits of biomedical enhancement will accrue primarily to those individuals who undergo enhancements, not to wider society. Buchanan has argued that biomedical enhancements might in fact have substantial social benefits by increasing productivity. We outline another way in which enhancements might benefit wider society: by augmenting civic virtue and thus improving the functioning of our political communities. We thus directly confront critics of biomedical enhancement who argue that it will lead to a loss of social cohesion and a breakdown in political lif

A multilevel model of multimarket contact: competence depletion and punctuated forbearance hypotheses

Multimarket contact (MMC) research establishes a positive relationship between MMC and firm-in-market level prices and margins, supporting the mutual forbearance hypothesis that firms confronting one another in multiple markets tacitly collude. This article proposes that the MMC dynamics generating short-term firm-in-market level advantages paradoxically undermine firm-level performance over the long term. Examining recursive relationships traversing levels of analysis, I integrate a distinctive competencies perspective with the prevailing positional advantage perspective on MMC. At the firm level, I contend that MMC undermines competence development. At the population level, I propose that MMC attenuates the concentration stability upon which forbearance rests, such that flurries of intense rivalry punctuate extended periods of mutual forbearance. For firms exposed to the competence depleting influences of MMC, punctuated forbearance threatens performance. The competence depletion and punctuated forbearance hypotheses here advanced promise to sensitize future research efforts to MMC’s adverse strategic implications

Structural investigations on experimentally and naturally produced slickensides

This work has involved an experimental approach and a study of naturally produced slickensides. The experiments, carried out on a pyrophyllitic rock, have been performed in order to define some extrinsic parameters that control surface and microstructural features. Normal stress, speed (i.e. strain rate), and amount of slip and total displacement were related to measureable surface features, such as length, and spacing between the developing ridges and grooves. Special attention was paid to a newly recognized type of slickenside lineation (Means, 1986). This lineation produced experimentally cannot be explained in terms of the traditional asperity ploughing or dissolution/precipitation models. It has the following distinctive features: (1) ridges and grooves are present, and occupy about the same amount of area of both hangingwall and footwall blocks, (2) ridges and grooves show a shallow U-shaped profile with planar bottom and top segments, (3) hangingwall and footwall blocks show complementary morphologies and fit perfectly into each other, (4) ridge and groove length can exceed the length of the slip displacement. A model is proposed to explain these features. It could be demonstrated that slickensides are penetrative features. In both, the deformed samples and the naturally produced slickensides, a strain-modified sub-surface zone of variable thickness is present. The microstructural features observed indicate a wide span of deformation processes ranging from brittle (intergranular cracks, open and refilled tension gashes, faulting) to ductile behaviour (undulose extinction, recrystallization). A new slickenside definition is proposed