Faculty and Staff

Readability formulas are used widely in education, and increasingly in business and government. Over 30 years of research on more than 200 readability formulas has demonstrated moderate to strong predictive correlations with reading comprehension. In this study, five well-known readability formulas correlated highly with each other when applied to selected recent historical articles (N = 22) from two music education research journals. The mean level of difficulty (readability) for all 22 articles was grade 14.04, near the beginning of the second year of college. Since research shows that most people read below their highest completed school grade and also prefer easier materials, this is probably an appropriate level of difficulty for the presumptive readers of these two journals (i.e., holders of undergraduate and graduate degrees). Professors, librarians, and others responsible for guiding students toward reading material at appropriate levels of readability could benefit from these results.

Poster about meeting the academic and cultural needs of international students at the Arizona State University Libraries and the University of Arizona Libraries. The poster presentation focuses on:

1. Strategies to promote information literacy skills of international students in the two university libraries.
2. What the libraries are doing to improve services to meet the needs and encourage library use among international students.
3. Partnerships that have been established with other academic departments or institutions.

Biological Soil Crusts (BSCs) are organosedimentary assemblages comprised of microbes and minerals in topsoil of terrestrial environments. BSCs strongly impact soil quality in dryland ecosystems (e.g., soil structure and nutrient yields) due to pioneer species such as Microcoleus vaginatus; phototrophs that produce filaments that bind the soil together, and support an array of heterotrophic microorganisms. These microorganisms in turn contribute to soil stability and biogeochemistry of BSCs. Non-cyanobacterial populations of BSCs are less well known than cyanobacterial populations. Therefore, we attempted to isolate a broad range of numerically significant and phylogenetically representative BSC aerobic heterotrophs. Combining simple pre-treatments (hydration of BSCs under dark and light) and isolation strategies (media with varying nutrient availability and protection from oxidative stress) we recovered 402 bacterial and one fungal isolate in axenic culture, which comprised 116 phylotypes (at 97% 16S rRNA gene sequence homology), 115 bacterial and one fungal. Each medium enriched a mostly distinct subset of phylotypes, and cultivated phylotypes varied due to the BSC pre-treatment. The fraction of the total phylotype diversity isolated, weighted by relative abundance in the community, was determined by the overlap between isolate sequences and OTUs reconstructed from metagenome or metatranscriptome reads. Together, more than 8% of relative abundance of OTUs in the metagenome was represented by our isolates, a cultivation efficiency much larger than typically expected from most soils. We conclude that simple cultivation procedures combined with specific pre-treatment of samples afford a significant reduction in the culturability gap, enabling physiological and metabolic assays that rely on ecologically relevant axenic cultures.

Readability formulas are used widely in education, and increasingly in business and government. Over 30 years of research on more than 200 readability formulas has demonstrated moderate to strong predictive correlations with reading comprehension. In this study, five well-known readability formulas correlated highly with each other when applied to selected recent historical articles (N = 22) from two music education research journals. The mean level of difficulty (readability) for all 22 articles was grade 14.04, near the beginning of the second year of college. Since research shows that most people read below their highest completed school grade and also prefer easier materials, this is probably an appropriate level of difficulty for the presumptive readers of these two journals (i.e., holders of undergraduate and graduate degrees). Professors, librarians, and others responsible for guiding students toward reading material at appropriate levels of readability could benefit from these results.

||中文摘要
《音樂教育研究期刊》與《音樂教育歷史研究期刊》中部分文章的閱讀難度水準
Alexandra H. Humphreys
Arizona State University—Phoenix, U.S.A.
Jere T. Humphreys
Arizona State University—Tempe, U.S.A.
可讀性估算公式被廣泛運用在教育領域，而且在商業和政府部門的使用頻率與日俱增。在過去的30 年裏，
研究人員共研發了200 多種可讀性估算公式，這些公式所估算的可讀性指標與實際閱讀理解程度具有中度
或很強的相關性。本文使用了五種著名的可讀性估算公式來評估最近發表的22 篇音樂教育史文章，發現這
五種公式的計算結果有很強的相關性。這22 篇文章的平均閱讀難度水準是14.04， 接近大學二年級初期的
閱讀水準。由於先前的研究结果显示大部分人喜歡閱讀難度水準低於本人學歷水準的文章以及比較容易理
解的文章，這兩種期刊中文章的閱讀難度水準非常適合預計的閱讀對象（有學士學位和研究生學位的人）。
本文研究結果可能會對那些大學教授，圖書館員和其他負責指導學生閱讀的人員有所幫助。

The heterocyclic indole-alkaloid scytonemin is a sunscreen found exclusively among cyanobacteria. An 18-gene cluster is responsible for scytonemin production in Nostoc punctiforme ATCC 29133. The upstream genes scyABCDEF in the cluster are proposed to be responsible for scytonemin biosynthesis from aromatic amino acid substrates. In vitro studies of ScyA, ScyB, and ScyC proved that these enzymes indeed catalyze initial pathway reactions. Here we characterize the role of ScyD, ScyE, and ScyF, which were logically predicted to be responsible for late biosynthetic steps, in the biological context of N. punctiforme. In-frame deletion mutants of each were constructed (ΔscyD, ΔscyE, and ΔscyF) and their phenotypes studied. Expectedly, ΔscyE presents a scytoneminless phenotype, but no accumulation of the predicted intermediaries. Surprisingly, ΔscyD retains scytonemin production, implying that it is not required for biosynthesis. Indeed, scyD presents an interesting evolutionary paradox: it likely originated in a duplication event from scyE, and unlike other genes in the operon, it has not been subjected to purifying selection. This would suggest that it is a pseudogene, and yet scyD is highly conserved in the scytonemin operon of cyanobacteria. ΔscyF also retains scytonemin production, albeit exhibiting a reduction of the production yield compared with the wild-type. This indicates that ScyF is not essential but may play an adjuvant role for scytonemin synthesis. Altogether, our findings suggest that these downstream genes are not responsible, as expected, for the late steps of scytonemin synthesis and we must look for those functions elsewhere. These findings are particularly important for biotechnological production of this sunscreen through heterologous expression of its genes in more tractable organisms.

N₂ fixation and ammonia oxidation (AO) are the two most important processes in the nitrogen (N) cycle of biological soil crusts (BSCs). We studied the short-term response of acetylene reduction assay (ARA) rates, an indicator of potential N₂ fixation, and AO rates to temperature (T, -5°C to 35°C) in BSC of different successional stages along the BSC ecological succession and geographic origin (hot Chihuahuan and cooler Great Basin deserts). ARA in all BSCs increased with T until saturation occurred between 15 and 20°C, and declined at 30–35°C. Culture studies using cyanobacteria isolated from these crusts indicated that the saturating effect was traceable to their inability to grow well diazotrophically within the high temperature range. Below saturation, temperature response was exponential, with Q₁₀ significantly different in the two areas (~ 5 for Great Basin BSCs; 2–3 for Chihuahuan BSCs), but similar between the two successional stages. However, in contrast to ARA, AO showed a steady increase to 30–35°C in Great Basin, and Chihuhuan BSCs showed no inhibition at any tested temperature. The T response of AO also differed significantly between Great Basin (Q₁₀ of 4.5–4.8) and Chihuahuan (Q₁₀ of 2.4–2.6) BSCs, but not between successional stages. Response of ARA rates to T did not differ from that of AO in either desert. Thus, while both processes scaled to T in unison until 20°C, they separated to an increasing degree at higher temperature. As future warming is likely to occur in the regions where BSCs are often the dominant living cover, this predicted decoupling is expected to result in higher proportion of nitrates in soil relative to ammonium. As nitrate is more easily lost as leachate or to be reduced to gaseous forms, this could mean a depletion of soil N over large landscapes globally.