Relationships between pyrimidine metabolism and sensitivity to alkylating agents in Aspergillus nidulans.

Relationships between pyrimidine metabolism and sensitivity to alkylating agents in Aspergillus nidulans

Some factors affecting transformation of Aspergillus nidulans - Problems and progress.

Some factors affecting transformation of Aspergillus nidulans - Problems and progress

Multimedia and its effects on different cognitive styles in the mathematics classroom

Technology has provided the education world with 3 many tools to present information. Multimedia is the latest tool. Multimedia in itself is not a new concept. In the past, teachers and students have used multiple forms of media to create projects such as filmstrips, tape recordings and videos. Today, the computer has become the conductor of the multimedia orchestra (Epstein, 1990, p. 40)

Ke models: Theoretical dynamic subsystems of longitudinal web strain

Efficient design and optimization of many production processes often require models which predict transient and steady state web strains. To date, much attention has been given to modeling web strains much less than unity. Considerably less attention however, has been given to modeling strains of relatively lower modulus materials. A particular related challenge often involves selection of dancers vs. load cells as feedback devices in tension control systems.This paper explores derivations of theoretical "Ke" models as primitive functions of roller motions. At a fundamental level, simple linear and nonlinear differential equations exist for each strain component or "subsystem" independent of others. Combinations can determine total strains in web spans including those at inputs and outputs of dancer rollers and within festoons. Validity is retained at any value of strain including zero and negative values (compression). The author demonstrates that mathematical equations of high web strains instead of becoming unwieldy, can be applied with accuracy and with a large degree of natural elegance. Applied classical control theory allows users a natural intuition when interpreting results which are primarily outputs of computer simulations.The "free web span" has been extensively studied within the web handling community and is again examined here as a 1st section of web under any dynamic strain feeding into a 2nd section of web between two driven rollers. A free web span Ke based model is compared to a first order approximate model of the same physical system while applying step changes to roller velocities. Both models are compared as final values of strain approach extremely high values toward infinity. Using Ke models, all strain-time trajectories in the free web span as a result of step changes to roller velocities are shown to be sections of an S-shaped curve designated "The Universal Strain Time Curve". The output of the first order approximate model, when plotted on the Universal Strain Time Curve (USTC), reveals that the first order approximate model may often be applied with acceptable results for strains from 0 through 25%. Finally, an example model of a tension control system with load cell feedback demonstrates how consecutively higher order subsystems may be included as elements of a Ke Subsystem Library.A practical and intuitive method of modeling web strains of any value has been developed here and may be applied by scientists and engineers having a basic knowledge of classical control system theory. With relatively accurate input data, effects on strain resulting from various roller inertias, web span lengths, dancers vs. load cells, and many other design decisions can be simulated. For both high and low modulus materials, Ke models provide a high degree of accuracy when simulating web strains during process design and optimization. This research is applicable to a broad spectrum of webs from thin plastics to paper, textiles, flat metals, wires, films, belts, foils, strips, threads, fabrics, and composites which are manufactured in rolling processes. The academic derivation process which has been applied also reinforces a useful framework to solve similar scientific problems

A sodium fluoride sensitive mutant of Aspergillus nidulans

Fluoride is a widely spread naturally occurring substance in many foods and is used extensively for industrial purposes. The addition of fluoride to drinking water has been assumed to be safe. However, a number of studies have indicated that sodium fluoride is both genotoxic and cytotoxic to mammalian cells (Tsutsui et al. 1984 Mut. Res. 139:193-198). There is conflicting evidence suggesting that NaF is not genotoxic (Kram et al. 1978 Mut. Res. 57:51-55; Martin et al. 1979 Mut. Res. 66:159-167; Li et al. 1987 Mut. Res. 192:191-202) and can suppress the activity of polyfunctional alkylating agents (Obe and Slacik-Erben 1973 Mut. Res. 18:369-371)

Reinventing College Physics for Biologists: Explicating an epistemological curriculum

The University of Maryland Physics Education Research Group (UMd-PERG) carried out a five-year research project to rethink, observe, and reform introductory algebra-based (college) physics. This class is one of the Maryland Physics Department's large service courses, serving primarily life-science majors. After consultation with biologists, we re-focused the class on helping the students learn to think scientifically -- to build coherence, think in terms of mechanism, and to follow the implications of assumptions. We designed the course to tap into students' productive conceptual and epistemological resources, based on a theoretical framework from research on learning. The reformed class retains its traditional structure in terms of time and instructional personnel, but we modified existing best-practices curricular materials, including Peer Instruction, Interactive Lecture Demonstrations, and Tutorials. We provided class-controlled spaces for student collaboration, which allowed us to observe and record students learning directly. We also scanned all written homework and examinations, and we administered pre-post conceptual and epistemological surveys. The reformed class enhanced the strong gains on pre-post conceptual tests produced by the best-practices materials while obtaining unprecedented pre-post gains on epistemological surveys instead of the traditional losses.Comment: 35 pages including a 15 page appendix of supplementary material

Expanding the parameters of academia

This paper draws on qualitative data gathered from two studies funded by the UK Leadership Foundation for Higher Education to examine the expansion of academic identities in higher education. It builds on Whitchurch’s earlier work, which focused primarily on professional staff, to suggest that the emergence of broadly based projects such as widening participation, learning support and community partnership is also impacting on academic identities. Thus, academic as well as professional staff are increasingly likely to work in multi-professional teams across a variety of constituencies, as well as with external partners, and the binary distinction between ‘academic’ and ‘non-academic’ roles and activities is no longer clear-cut. Moreover, there is evidence from the studies of an intentionality about deviations from mainstream academic career routes among respondents who could have gone either way. Consideration is therefore given to factors that influence individuals to work in more project-oriented areas, as well as to variables that affect ways in which these roles and identities develop. Finally, three models of academically oriented project activity are identified, and the implications of an expansion of academic identities are reviewed

The use of continuous spectral analysis for the assessment of postural stability changes after sports-related concussion

© 2019 Elsevier Ltd Impaired postural stability is associated with a variety of pathologies including sports-related concussion (SRC). Quantification of centre of pressure (COP) movement is the most common focus of instrumented assessment. Frequency-domain COP analyses have focused primarily on summary measures or pre-defined frequency bands but continuous analysis may provide novel and complementary insight into pathological control mechanisms. Our aims were (i) to compare post-SRC COP trajectory changes identified using clinician scores (Modified Balance Error Scoring System (M-BESS)), time-domain COP variables and continuous frequency spectral comparison; and (ii) to characterise frequency spectra changes. Male rugby players aged 15–19 years (n = 135) completed a pre-season baseline assessment comprising vision-obscured double-leg, single-leg and tandem stances on a force platform. Participants diagnosed with SRC during the season (n = 15) underwent repeat testing (median 4 days post-SRC; IQR 2.5–6.5). Baseline and post-SRC COP trajectories were compared using common time-domain COP variables, M-BESS scores and continuous frequency spectra. Post-SRC changes were identified using all three approaches. Spectral analysis revealed the largest effect size (Cliff's delta 0.39) and was the only method to identify differences in all three stances and in double-leg stance. All post-SRC increases in spectral content were in the anteroposterior direction; all decreases were in the mediolateral direction. Changes were localised to higher frequencies (1.7–8 Hz) except for double-leg stance anteroposterior direction, for which increases were observed throughout the analysed range. Our findings suggest that this method of spectral comparison may provide a more responsive and meaningful measure of postural stability changes after SRC than other commonly-used variables