OXYGEN CONSUMPTION: EFFECT OF LATERAL PEDAL WIDTH VARIATIONS RELATIVE TO Q-ANGLE IN AVID CYCLISTS

Twenty cyclists completed four trials at 50% of maximal effort. Trials were performed at four different lateral widths (0, 20mm, 25mm, and 30mm) by adding a Kneesaver™ pedal spacer between the crank arm and pedal. Each trial lasted five minutes, during which analysis of expired air took place, as well as video analysis for digitizing purposes. The aim of the study was to determine if changing this lateral pedal width affected oxygen consumption and if lateral pedal width changed Q-angle in the cyclists. Statistically width did not affect Q-angle or oxygen consumption, however a significant, but small correlation was found between Q-angle and oxygen consumption

A Multi-Level Optimization Algorithm and a Ship Design Application

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97130/1/AIAA2012-5555.pd

Context Differences Reveal Insulator and Activator Functions of a Su(Hw) Binding Region

Insulators are DNA elements that divide chromosomes into independent transcriptional domains. The Drosophila genome contains hundreds of binding sites for the Suppressor of Hairy-wing [Su(Hw)] insulator protein, corresponding to locations of the retroviral gypsy insulator and non-gypsy binding regions (BRs). The first non-gypsy BR identified, 1A-2, resides in cytological region 1A. Using a quantitative transgene system, we show that 1A-2 is a composite insulator containing enhancer blocking and facilitator elements. We discovered that 1A-2 separates the yellow (y) gene from a previously unannotated, non-coding RNA gene, named yar for y-achaete (ac) intergenic RNA. The role of 1A-2 was elucidated using homologous recombination to excise these sequences from the natural location, representing the first deletion of any Su(Hw) BR in the genome. Loss of 1A-2 reduced yar RNA accumulation, without affecting mRNA levels from the neighboring y and ac genes. These data indicate that within the 1A region, 1A-2 acts an activator of yar transcription. Taken together, these studies reveal that the properties of 1A-2 are context-dependent, as this element has both insulator and enhancer activities. These findings imply that the function of non-gypsy Su(Hw) BRs depends on the genomic environment, predicting that Su(Hw) BRs represent a diverse collection of genomic regulatory elements

The objectivity of local knowledge. Lessons from ethnobiology

This article develops an account of local epistemic practices on the basis of case studies from ethnobiology. I argue that current debates about objectivity often stand in the way of a more adequate understanding of local knowledge and ethnobiological practices in general. While local knowledge about the biological world often meets criteria for objectivity in philosophy of science, general debates about the objectivity of local knowledge can also obscure their unique epistemic features. In modification of Ian Hacking’s suggestion to discuss “ground level questions” instead of objectivity, I propose an account that focuses on both epistemic virtues and vices of local epistemic practices

Ribonuclease T: new exoribonuclease possibly involved in end-turnover of tRNA.

Examination of double mutants lacking one of the exoribonucleases, RNase II, RNase D, RNase BN, or RNase R, and also devoid of tRNA nucleotidyltransferase has suggested that none of these RNases participates in the end-turnover of tRNA. This prompted a search for and identification of a new exoribonuclease, termed RNase T. RNase T could be detected in mutant Escherichia coli strains lacking as many as three of the known exoribonucleases, and it could be separated from each of the four previously described RNases. RNase T is optimally active at pH 8-9 and requires a divalent cation for activity. The enzyme is sensitive to ionic strengths greater than 50 mM and is rapidly inactivated by heating at 45 degrees C. Its preferred substrate is tRNA-C-C-[14C]A, with much less activity shown against tRNA-C-C. RNase T is an exoribonuclease that initiates attack at the 3' hydroxyl terminus of tRNA and releases AMP in a random mode of hydrolysis. The possible involvement of RNase T in end-turnover of tRNA and in RNA metabolism in general are discussed

RNase T is responsible for the end-turnover of tRNA in Escherichia coli.

A mutant strain deficient in RNase T was isolated and used to study the role of this enzyme in Escherichia coli. Strains lacking as much as 70% of RNase T activity, alone or in combination with the absence of other RNases, display normal growth properties. However, in cca strains, which lack tRNA nucleotidyltransferase, RNase T-deficient derivatives accumulate lower levels of defective tRNA and grow at increased rates compared to their RNase T+ parents. Slow-growing cca strains revert to a faster-growing form that contains less defective tRNA but which is still cca. All of these strains have decreased levels of RNase T. These data indicate that RNase T is responsible for nucleotide removal during the tRNA end-turnover process and that the amount of defective tRNA in cells is determined by the relative levels of RNase T and tRNA nucleotidyltransferase

Disturbance and wetland type alter reed canarygrass cover in northern Michigan

Although much is known about the physiological capabilities of reed canarygrass (RCG) and the consequences of invasion, less is known about the roles that wetland type and surrounding disturbances play in facilitating the spread of RCG in predominantly forested landscapes. Therefore, the goals of our study were to test if (1) certain wetland types in the Northern Great Lakes region were more susceptible to RCG invasion, (2) certain disturbances facilitated RCG, and (3) the level of road development and the presence or absence of a ditch bordering each observed road influences the frequency of adjacent RCG populations. We randomly selected 28 wetlands within the Keweenaw Bay Indian Community reservation in the Upper Peninsula of Michigan. At each wetland, we collected plant community and environmental data and catalogued disturbances. In all, 287 plant species were identified. Cluster analysis revealed 16 distinct vegetation communities, which were distributed among three broader wetland community types: (1) nonforested graminoid, (2) Sphagnum peatlands, and (3) forested wetlands. Occurrence of RCG was most common in the nonforested graminoid communities and was also positively correlated to disturbance. The most frequent disturbances were roads, off-road vehicle trails, and logging activity. Additionally, paved and graded roads, and roads with ditches, were more likely to have RCG alongside them than unpaved dirt roads. Our data suggest that RCG occurrence is controlled by interactions between wetland types and disturbance. © 2013 Weed Science Society of America