Thermoradiation inactivation of naturally occurring organisms in soil

Samples of soil collected from Kennedy Space Center near spacecraft assembly facilities were found to contain microorganisms very resistant to conventional sterilization techniques. The inactivation behavior of the naturally occurring spores in soil was investigated using dry heat and ionizing radiation, first separately, then in combination. Dry heat inactivation rates of spores were determined for 105 and 125 C. Radiation inactivation rates were determined for dose rates of 660 and 76 krad/hr at 25 C. Simultaneous combinations of heat and radiation were then investigated at 105, 110, 115, 120, and 125 C. Combined treatment was found to be highly synergistic requiring greatly reduced radiation doses to accomplish sterilization

Rates of molecular evolution and diversification in plants: chloroplast substitution rates correlate with species-richness in the Proteaceae

BACKGROUND Many factors have been identified as correlates of the rate of molecular evolution, such as body size and generation length. Analysis of many molecular phylogenies has also revealed correlations between substitution rates and clade size, suggesting a link between rates of molecular evolution and the process of diversification. However, it is not known whether this relationship applies to all lineages and all sequences. Here, in order to investigate how widespread this phenomenon is, we investigate patterns of substitution in chloroplast genomes of the diverse angiosperm family Proteaceae. We used DNA sequences from six chloroplast genes (6278bp alignment with 62 taxa) to test for a correlation between diversification and the rate of substitutions. RESULTS Using phylogenetically-independent sister pairs, we show that species-rich lineages of Proteaceae tend to have significantly higher chloroplast substitution rates, for both synonymous and non-synonymous substitutions. CONCLUSIONS We show that the rate of molecular evolution in chloroplast genomes is correlated with net diversification rates in this large plant family. We discuss the possible causes of this relationship, including molecular evolution driving diversification, speciation increasing the rate of substitutions, or a third factor causing an indirect link between molecular and diversification rates. The link between the synonymous substitution rate and clade size is consistent with a role for the mutation rate of chloroplasts driving the speed of reproductive isolation. We find no significant differences in the ratio of non-synonymous to synonymous substitutions between lineages differing in net diversification rate, therefore we detect no signal of population size changes or alteration in selection pressures that might be causing this relationship.This work was funded by the Australian Research Council

Qualitative, Tiered, iClicker Recitation Introductions

Interactively engaging students can significantly help them understand key concepts [Hake 1998]. Additionally, students are most likely to recall the first five minutes of a presentation [Burns 1985]. Capitalizing on both of these, we altered the beginning of PHYS 272 (ELECTRIC AND MAGNETIC INTERACTIONS) recitation to include a series of qualitative, “tiered,” iClicker questions that interactively engage students and socratically teach fundamental principals in electricity and magnetism. The series begin with a question that most students comfortably and correctly answer. Successive questions increase in difficultly and the series stops with most students struggling to identify the correct answer. Along the way, the teaching assistant explains the validity of the correct answer and the shortcomings of the wrong answers. Thus tiered questions are valuable to a wider range of the different levels of conceptual understandings present in the students of each recitation [Keller 2007]. Students who struggle benefit at the beginning and experts at the end. After the iClicker introduction, and now armed with a fuller qualitative understanding, the students work collaboratively in small groups on quantitative problems that employ the same principals. PHYS 272 is a foundational course with a typical yearly enrollment over 500. It’s our goal to demonstrate that qualitative, tiered introductions coupled with quantitative collaborative work positively impacts student’s overall learning gain measured by the Brief Electricity and Magnetism Assessment. If successful, linking qualitative with quantitative instruction could benefit the thousands of students who take PHYS 272 in the years to come. References: Burns, R. A. (1985). Information Impact and Factors Affecting Re- call. Presented at Annual National Conference on Teaching Excel- lence and Conference of Administrators, Austin, TX, May 22–25, 1985. (ERIC Document No. ED 258 639) Hake, R. R. (1998). Interactive-engagement versus traditional methods : A six-thousand-student survey of mechanics test data for introductory physics courses. American Journal of Physics, 66 (May 1996), 64–74. Keller, C., Finkelstein, N., Perkins, K., Pollock, S., Turpen, C., Dubson, M., … McCullough, L. (2007). Research-based Practices For Effective Clicker Use. AIP Conference Proceedings, 128–131. doi:10.1063/1.282091

ESTATE PLANNING IN NORTH DAKOTA: THE BASICS Part 4: Trusts

Formerly published under the HE seriesFE-554 (Revised

Nutrient uptake of wheat from several fertilizers as evaluated by laboratory analyses

Call number: LD2668 .T4 1963 L56Master of Scienc

A note on the expressive power of linear orders

This article shows that there exist two particular linear orders such that first-order logic with these two linear orders has the same expressive power as first-order logic with the Bit-predicate FO(Bit). As a corollary we obtain that there also exists a built-in permutation such that first-order logic with a linear order and this permutation is as expressive as FO(Bit)