Ethnography, education and on-line research

This paper is an attempt to establish the methodological basis for carrying out ethnographies of online education communities, in particular in the Continuing Professional Development VITAL project co-ordinated by the Faculty of Education and Language Studies at The Open University www.vital.ac.uk/ A much shorter earlier draft version of this paper was given at the Qualitative Research For Web 2.0/3.0: The Next Leap! 25 & 26 March 2010 in Berlin. Organised by Merlien. The arguments and references in this paper are almost all to be found in two books 'one authored and one edited – by Professor Christine Hine of Surrey University, UK (Hine 2000; Hine 2005)

Bean pod mottle virus biology and management in Iowa

Bean pod mottle virus (BPMV) and bean leaf beetles, Cerotoma trifurcata (Forster), both reduce yield and seed quality in soybean, Glycine max (L.). Numerous beetle species can transmit BPMV; however, recent outbreak populations of bean leaf beetles have contributed to an epidemic of BPMV in soybean in Iowa. The objective of this research was to understand or identify the contributing sources of the BPMV epidemic in nature and to study novel chemical control tactics for the management of this pest complex. To facilitate the measurement of leaf herbivory of leaves, a tool was developed for the digital measurement of leaf surface area. The effects of shape, size, and capture resolution on digital area measurement were investigated to accurately and precisely estimate leaf surface area. The results indicated that image capture resolutions of either 118.16 or 236.27 pixels cm-1 (300 or 600 pixels in-1, respectively) had the least bias for a variety of sizes and were least affected by shape geometry. Eighteen field-collected, perennial plant species were tested for the presence of BPMV and acceptability to bean leaf beetle herbivory. Five new food hosts, Lespedeza capitata (Michaux), Lotus corniculatus L., Trifolium alexandrinum L., T. ambiguum Bieberstein, and T. incarnatum L., were discovered for bean leaf beetles and one new host, Desmodium illinoense Gray, for BPMV. All of these plant species emerge prior to normal emergence times for soybean in Iowa. The nucleotide and amino acid sequence from the D. illinoense BPMV isolate (I-Di1) was characterized. I-Di1 was determined as a new natural reassortant of BPMV belonging to RNA-1 subgroup I, RNA-2 subgroup II. The nucleotide and amino acid sequences from BPMV isolates (I-P) from an adjacent soybean field were partially characterized. The I-P isolates were all of RNA-1 subgroup II and thus do not appear to be related to I-Di1. However, based on nucleotide sequence analysis the within-field isolate diversity is high. Soybean growers desire earlier planting dates and given the spring-feeding activity of the bean leaf beetle and the potential of early-season injury of soybean from BPMV infection, early planting dates are at risk. Therefore the effects of seedapplied and foliar insecticides on this pest complex were studied within the context of the currently-recommended management strategy: the use of insecticides to reduce F0 and F1 bean leaf beetle populations. The use of a seed-applied insecticide to target F 0 beetles (followed by a foliar insecticide application targeting F 1 bean leaf beetles) gave the greatest improvement in yield (0.9 q ha -1 [∼1.3 bu a-1] at two locations in one year. However, seed quality was protected most if a foliar insecticide was used to suppress F0 and F1 beetles. This work presents discoveries regarding the host range of bean leaf beetles and BPMV, evidence for within-field evolution of BPMV, and provides research results for a novel management tactic for controlling bean leaf beetles and BPMV

Diagnosing the time-dependence of active region core heating from the emission measure: II. Nanoflare trains

The time-dependence of heating in solar active regions can be studied by analyzing the slope of the emission measure distribution cool-ward of the peak. In a previous study we showed that low-frequency heating can account for 0% to 77% of active region core emission measures. We now turn our attention to heating by a finite succession of impulsive events for which the timescale between events on a single magnetic strand is shorter than the cooling timescale. We refer to this scenario as a "nanoflare train" and explore a parameter space of heating and coronal loop properties with a hydrodynamic model. Our conclusions are: (1) nanoflare trains are consistent with 86% to 100% of observed active region cores when uncertainties in the atomic data are properly accounted for; (2) steeper slopes are found for larger values of the ratio of the train duration $\Delta_H$ to the post-train cooling and draining timescale $\Delta_C$, where $\Delta_H$ depends on the number of heating events, the event duration and the time interval between successive events ($\tau_C$); (3) $\tau_C$ may be diagnosed from the width of the hot component of the emission measure provided that the temperature bins are much smaller than 0.1 dex; (4) the slope of the emission measure alone is not sufficient to provide information about any timescale associated with heating - the length and density of the heated structure must be measured for $\Delta_H$ to be uniquely extracted from the ratio $\Delta_H/\Delta_C$

X-ray Source Heights in a Solar Flare: Thick-target versus Thermal Conduction Front Heating

Observations of solar flares with RHESSI have shown X-ray sources traveling along flaring loops, from the corona down to the chromosphere and back up. The 28 November 2002 C1.1 flare, first observed with RHESSI by Sui et al. 2006 and quantitatively analyzed by O'Flannagain et al. 2013, very clearly shows this behavior. By employing numerical experiments, we use these observations of X-ray source height motions as a constraint to distinguish between heating due to a non-thermal electron beam and in situ energy deposition in the corona. We find that both heating scenarios can reproduce the observed light curves, but our results favor non-thermal heating. In situ heating is inconsistent with the observed X-ray source morphology and always gives a height dispersion with photon energy opposite to what is observed.Comment: Accepted to Ap

Design knowledge capture for a corporate memory facility

Currently, much of the information regarding decision alternatives and trade-offs made in the course of a major program development effort is not represented or retained in a way that permits computer-based reasoning over the life cycle of the program. The loss of this information results in problems in tracing design alternatives to requirements, in assessing the impact of change in requirements, and in configuration management. To address these problems, the problem was studied of building an intelligent, active corporate memory facility which would provide for the capture of the requirements and standards of a program, analyze the design alternatives and trade-offs made over the program's lifetime, and examine relationships between requirements and design trade-offs. Early phases of the work have concentrated on design knowledge capture for the Space Station Freedom. Tools are demonstrated and extended which helps automate and document engineering trade studies, and another tool is being developed to help designers interactively explore design alternatives and constraints

Bean leaf beetles: a current and historical perspective

In 2002, bean leaf beetle populations in Iowa reached their highest levels in 14 years (figure, left). In Iowa, this increase in beetle populations has been partly fueled by weather conditions that favor winter survival, such as mild temperatures (2001-2002: second mildest winter on record) or snow cover (2000-2001: snow cover for 99 consecutive days in central Iowa). The increase in beetle populations has followed the trend for warmer weather during the previous six winters (figure, right)

Bean leaf beetles and soybean planting date

Considering the enormous bean leaf beetle populations in recent years, many soybean growers are interested in options for managing this pest. Cultural control, such as planting date, could be very useful for managing bean leaf beetle. Studies conducted by Larry Pedigo and Mike Zeiss at Iowa State University (1998-1992) quantified the effects of soybean planting date on bean leaf beetle abundance, soybean pod injury, and soybean yield