Nonpartisan election formats do not affect voting behaviors

Nonpartisan elections—in which candidates are not endorsed by a political party and their party affiliation does not appear on the ballot—have been criticized as depriving crucial information to voters, making it difficult for them to vote for candidates that represent their beliefs. Chris W. Bonneau and Damon M. Cann tested the impact of nonpartisan election conditions using both a laboratory experiment and data from the Cooperative Congressional Election Survey. They find that there is no significant difference between voting behaviors in partisan and nonpartisan election formats

A 14-day ground-based hypokinesia study in nonhuman primates: A compilation of results

A 14 day ground based hypokinesia study with rhesus monkeys was conducted to determine if a spaceflight of similar duration might affect bone remodeling and calcium homeostatis. The monkeys were placed in total body casts and sacrificed either immediately upon decasting or 14 days after decasting. Changes in vertebral strength were noted and further deterioration of bone strength continued during the recovery phase. Resorption in the vertebrae increased dramatically while formation decreased. Cortical bone formation was impaired in the long bones. The immobilized animals showed a progressive decrease in total serum calcium which rebounded upon remobilization. Most mandibular parameters remained unchanged during casting except for retardation of osteon birth or maturation rate and density distribution of matrix and mineral moieties

Mitochondrial Dna Replacement Versus Nuclear Dna Persistence

In this paper we consider two populations whose generations are not overlapping and whose size is large. The number of males and females in both populations is constant. Any generation is replaced by a new one and any individual has two parents for what concerns nuclear DNA and a single one (the mother) for what concerns mtDNA. Moreover, at any generation some individuals migrate from the first population to the second. In a finite random time $T$, the mtDNA of the second population is completely replaced by the mtDNA of the first. In the same time, the nuclear DNA is not completely replaced and a fraction $F$ of the ancient nuclear DNA persists. We compute both $T$ and $F$. Since this study shows that complete replacement of mtDNA in a population is compatible with the persistence of a large fraction of nuclear DNA, it may have some relevance for the Out of Africa/Multiregional debate in Paleoanthropology

IN VITRO STUDIES OF MAMMALIAN SOMATIC CELL VARIATION : I. DETECTION OF H-2 PHENOTYPE IN CULTURED MOUSE CELL LINES

The isoantigenic phenotype of the H-2 locus has been detected by isohemagglutinin absorption in a line of mouse lymphoma cells growing continuously in culture for 6 years and in two established lines of fibroblastic mouse cells growing continuously in culture for 1 year. Quantitative absorption studies suggest that the concentration of H-2 isoantigens is higher in the cultured lymphoma cells than in the other two fibroblastic cell lines

Real-time observation of fluid flows in tissue during stress relaxation using Raman spectroscopy

This paper outlines a technique to measure fluid levels in articular cartilage tissue during an unconfined stress relaxation test. A time series of Raman spectrum were recorded during relaxation and the changes in the specific Raman spectral bands assigned to water and protein were monitored to determine the fluid content of the tissue. After 1000 s unconfined compression the fluid content of the tissue is reduced by an average of 3.9% ± 1.7%. The reduction in fluid content during compression varies between samples but does not significantly increase with increasing strain. Further development of this technique will allow mapping of fluid distribution and flows during dynamic testing making it a powerful tool to understand the role of interstitial fluid in the functional performance of cartilage

A review of recent determinations of the composition and surface pressure of the atmos- phere of mars

Recent determinations of composition and surface pressure of Mars atmospher

Response of Archaeal Communities in the Rhizosphere of Maize and Soybean to Elevated Atmospheric CO2 Concentrations

BACKGROUND: Archaea are important to the carbon and nitrogen cycles, but it remains uncertain how rising atmospheric carbon dioxide concentrations ([CO(2)]) will influence the structure and function of soil archaeal communities. METHODOLOGY/PRINCIPAL FINDINGS: We measured abundances of archaeal and bacterial 16S rRNA and amoA genes, phylogenies of archaeal 16S rRNA and amoA genes, concentrations of KCl-extractable soil ammonium and nitrite, and potential ammonia oxidation rates in rhizosphere soil samples from maize and soybean exposed to ambient (∼385 ppm) and elevated (550 ppm) [CO(2)] in a replicated and field-based study. There was no influence of elevated [CO(2)] on copy numbers of archaeal or bacterial 16S rRNA or amoA genes, archaeal community composition, KCl-extractable soil ammonium or nitrite, or potential ammonia oxidation rates for samples from maize, a model C(4) plant. Phylogenetic evidence indicated decreased relative abundance of crenarchaeal sequences in the rhizosphere of soybean, a model leguminous-C(3) plant, at elevated [CO(2)], whereas quantitative PCR data indicated no changes in the absolute abundance of archaea. There were no changes in potential ammonia oxidation rates at elevated [CO(2)] for soybean. Ammonia oxidation rates were lower in the rhizosphere of maize than soybean, likely because of lower soil pH and/or abundance of archaea. KCl-extractable ammonium and nitrite concentrations were lower at elevated than ambient [CO(2)] for soybean. CONCLUSION: Plant-driven shifts in soil biogeochemical processes in response to elevated [CO(2)] affected archaeal community composition, but not copy numbers of archaeal genes, in the rhizosphere of soybean. The lack of a treatment effect for maize is consistent with the fact that the photosynthesis and productivity of maize are not stimulated by elevated [CO(2)] in the absence of drought

Zirconia phase transformation in retrieved, wear simulated and artificially aged ceramic femoral heads

Zirconia in Zirconia toughened alumina ceramic hip replacements exists in an unstable state and can transform in response to stress giving the material improved fracture toughness. Phase transformation also occurs under hydrothermal conditions such as exist in vivo. To predict the hydrothermal aging that will occur in vivo accelerated aging procedures have been used, but validation of these models requires the study of retrieved hip joints. Here 26 retrievals are analysed to determine the degree of phase transformation in vivo. These were compared with virgin heads, heads that had undergone the accelerated aging process and heads wear tested to 5 million cycles in a hip simulator. Monoclinic content and surface roughness were measured using Raman spectroscopy and white light interferometry respectively. The monoclinic content for retrieved heads was 28.5% ± 7.8, greater than twice that in virgin, aged or wear tested heads and did not have a significant correlation with time, contrary to the predictions of the hydrothermal aging model. The surface roughness for retrieved heads in the unworn area was not significantly different to that in virgin, aged or unworn areas of wear tested heads. However in worn areas of the retrieved heads, the surface roughness was higher than observed in wear simulator testing. These results indicate that current testing methodologies do not fully capture the operational conditions of the material and the real performance of future new materials may not be adequately predicted by current pre-clinical testing methods. This article is protected by copyright. All rights reserve

Tribological evaluation of a novel hybrid for repair of articular cartilage defects

The friction and wear properties of silica/poly(tetrahydrofuran)/poly(ε-caprolactone) (SiO2/PTHF/PCL-diCOOH) hybrid materials that are proposed as cartilage tissue engineering materials were investigated against living articular cartilage. A testing rig was designed to allow testing against fresh bovine cartilage. The friction force and wear were compared for five compositions of the hybrid biomaterial articulating against freshly harvested bovine cartilage in diluted bovine calf serum. Under a non-migrating contact, the friction force increased and hence shear force applied to the opposing articular cartilage also increased, resulting in minor damage to the cartilage surface. This worse case testing scenario was used to discriminate between material formulations and revealed the increase in friction and damaged area was lowest for the hybrid containing the most silica. Further friction and wear tests on one hybrid formulation with an elastic modulus closest to that of cartilage were then conducted in a custom incubator system. This demonstrated that over a five day period the friction force, cell viability and glucosaminoglycan (GAG) release into the lubricant were similar between a cartilage-cartilage interface and the hybrid-cartilage interface, supporting the use of these materials for cartilage repair. These results demonstrate how tribology testing can play a part in the development of new materials for chondral tissue engineering

Surface-plasmon-enhanced light scattering from microscopic spheres

Copyright © 2003 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters 83 (2003) and may be found at http://link.aip.org/link/?APPLAB/83/3006/1The enhanced light scattering from microscopic latex spheres placed in the optical field associated with a surface-plasmon resonance is explored. Spheres of 200 nm diameter are placed on an optically thin gold film that supports the surface-plasmon and the scattered intensity is then measured as a function of scattering angle. This is compared to the scattering profiles obtained from spheres placed on a bare glass substrate. In both cases, the experimental data are compared to theory. This system is of interest in the field of optical biosensing