Partisan Efficiency in an Open-Rule Setting: The Amending Process in the U.S. Senate, 1865–1945

Given significant differences between the House and Senate's amending processes, one would anticipate the Senate majority party to be far less successful when voting on the floor. However, recent work has demonstrated that majority party success on the Senate floor is remarkably similar to the House. We argue that an overlooked explanation for majority party success stems from its ability to control intra-party amending activity through coordination between members of the majority party. Utilizing a new data set consisting of all amendments receiving recorded roll call votes in the Senate from 1865–1945, we demonstrate that majority party extremists refrain from offering amendments despite the relative open-floor setting. Nevertheless, chamber majorities cannot restrict minority legislators from offering amendments designed to force them to cast uncomfortable votes and delay the legislative process.     

Technology based evolution? A biometric test of the effects of handsize versus tool form on efficiency in an experimental cutting task

The use of stone cutting tools opened a novel adaptive niche for hominins. Hence, it has been hypothesised that biomechanical adaptations evolved to maximise efficiency when using such tools. Here, we test experimentally whether biometric variation influences the efficiency of simple cutting tools (n = 60 participants). Grip strength and handsize were measured in each participant. 30 participants used flint flakes, while the other 30 used small (unhafted) steel blades. Variations in basic parameters of tool form (length, width, thickness, cutting edge length) were recorded for the 30 flint flakes. It was ensured that mean handsize and strength in each participant group were not significantly different to investigate the effect of tool variation. The experimental task required cutting through a 10 mm-diameter hessian rope. Cutting efficiency was measured using both ‘Number of cutting strokes required’ and ‘Total time taken’. Results show that both efficiency measures were significantly correlated with handsize using all 60 participants. However, no significant differences were found between the flake and blade groups in terms of mean efficiency. Nor was any significant relationship found between tool form parameters and efficiency in the flint flake group. We stress that our results do not imply that tool form has no impact on tool efficiency, but rather that – all other things being equal – biometric variation has a statistically significant influence on efficiency variation when using simple cutting tools. These results demonstrate that biomechanical parameters related directly to efficiency of use, may plausibly have been subject to selection in the earliest stone tool-using hominins.     

Ancient DNA typing of archaeological pig remains corroborates historical records

The recent increase in both the abundance and taxonomic range of DNA sequence data in public repositories makes it possible to determine the maternal origin of lineages of faunal archaeological material by characterizing its mitochondrial DNA. Among the most commonly represented taxa are domesticated animals, for which extensive genetic characterization has revealed high levels of genetic diversity and (in at least some cases) strong phylogeographic clustering. Such information has significant implications not only for characterizing important aspects of the occupation history of archaeological sites, but also in providing novel insights into colonisation history and the scale and scope of trade and exchange networks. This can be done through studying the origins and dispersal of proxy organisms such as commensal and domesticated animals, as well as economically important wild fauna. To illustrate this approach, we compare historical records of maritime movement of people and pigs from two sites on Lord Howe Island, Australia, to phylogeographic results of DNA extracted from pig bones.     

Expectations of scatter in equivalent-dose distributions when using multi-grain aliquots for OSL dating

In the OSL dating of sediment, the scatter in equivalent dose (D _e) between grains is almost always larger than would be expected due to counting statistics alone. Some scatter may be caused by insufficient (partial) bleaching of some of the grains prior to deposition. In order to date partially bleached sediment, it is essential to estimate the amount of scatter caused by other processes (e.g. grain-to-grain variability in the natural dose rate). Measurements of such scatter are performed at the single-grain level; by contrast, most OSL dating is performed on multi-grain subsamples, for which grain-to-grain scatter is reduced through averaging.