Radiation-induced insulator discharge pulses in the CRRES internal discharge monitor satellite experiment

The Internal Discharge Monitor (IDM) was designed to observe electrical pulses from common electrical insulators in space service. The sixteen insulator samples included twelve planar printed circuit boards and four cables. The samples were fully enclosed, mutually isolated, and space radiation penetrated 0.02 cm of aluminum before striking the samples. Pulsing began on the seventh orbit, the maximum pulse rate occurred on the seventeenth orbit when 13 pulses occurred, and the pulses slowly diminished to about one per 3 orbits six months later. After 8 months, the radiation belts abruptly increased and the pulse rates attained a new high. These pulse rates were in agreement with laboratory experience on shorter time scales. Several of the samples never pulsed. If the pulses were not confined within IDM, the physical processes could spread to become a full spacecraft anomaly. The IDM results indicate the rate at which small insulator pulses occur. Small pulses are the seeds of larger satellite electrical anomalies. The pulse rates are compared with space radiation intensities, L shell location, and spectral distributions from the radiation spectrometers on the Combined Release and Radiation Effects Satellite

Sorghum ergot - a sticky disease problem in southern Africa

Ergot disease of sorghum is not new to Africa - the causal pathogen, Claviceps africana Frederickson, Mantle, and de Milliano was first recorded in Kenya as far back as 1923. However, ergot disease only began to gain recognition as a potential problem in sorghum production in the 1960s, when all the A-lines in Nigeria's national breeding program became infected, to the near complete exclusion of seed production (Futrell and Webster 1965)

Potential Use of Benomyl for Control of Ergot (Claviceps africana) in Sorghum A-lines in Zimbabwe

In the absence of a successful practice for the control of ergot (caused by C. africana) on sorghum A-lines (male-steriles) in Zimbabwe, 2 fungicides, benomyl as Benlate and thiram, were tested in greenhouse and field experiments conducted at the Matopos and Henderson Research Stations, Zimbabwe in 1993. Fungicides were either applied to sorghum panicles singly, at concentrations of 0.1 or 0.2% a.i., or combined in mixtures at 0.1% a.i. each. Fungicides were applied before inoculation at heading or stigma exsertion or after disease became visible. Treatment with either benomyl or thiram was ineffective if applied when disease first became visible. A significant reduction in initial disease severity, rate of disease increase and final disease severity was achieved with 1 application of benomyl at 0.2% a.i. at heading or stigma exsertion. At the concentrations tested benomyl and thiram did not reduce seed-set in R- (restorer) lines

Pearl Millet as an Alternate Host of the Sorghum Ergot Pathogen, Claviceps africana

The infectivity of C. africana on pearl millet (Pennisetum glaucum) lines in Africa was studied. C. africana consistently gave 100% disease incidence on male-sterile sorghum in experiments undertaken in Zimbabwe. C. fusiformis established disease with moderate incidence on most but not all lines tested. In contrast, C. africana established a parasitic association with all the pearl millet lines tested, with incidence as high as 23% in ICMSR 260, the genotype that also supported the highest incidence with C. fusiformis. However, the disease severities were always low, between 1 and 5%. All infections on pearl millet were verified as the sphacelial stage by virtue of their conidial characteristics. After 1 passage through a pearl millet host, C. africana did not apparently become more infectious on this host

RMT 555 - PERSEKITARAN PERUNDANGAN APRIL-MAY 06.

Abstract. We present a linear time algorithm for computing an implicit linear space representation of a minimum cycle basis (MCB) in weighted partial 2-trees, i.e., graphs of treewidth two. The implicit representation can be made explicit in a running time that is proportional to the size of the MCB. For planar graphs, Borradaile, Sankowski, and Wulff-Nilsen [Min st-cut Oracle for Planar Graphs with Near-Linear Preprocessing Time, FOCS 2010] showed how to compute an implicit O(n log n) space representation of an MCB in O(n log 5 n) time. For the special case of partial 2-trees, our algorithm improves this result to linear time and space. Such an improvement was achieved previously only for outerplanar graphs [Liu and Lu: Minimum Cycle Bases of Weighted Outerplanar Graphs, IPL 110:970–974, 2010]

Ergot: A New Disease Threat to Sorghum in the Americas and Australia

Sorghum, Sorghum bicolor (L.) Moench, is the world’s fifth most important cereal crop, cultivated on about 45 million hectares for food, feed, beverage, and fodder. The most significant technological change since the 1960s has been the development and use of F1 hybrid seed (14), which has lead to a dramatic improvement in the crop’s productivity. Sorghum cultivation in intensive, commercialized systems where yields average 3 to 5 t ha-1 relies almost totally on hybrid seed. In contrast, yields vary widely and average less than 1 t ha-1 in low-input production systems

Multi-Informant Predictors of Social Inclusion for Students with Autism Spectrum Disorders Attending Mainstream School

This study examined differential profiles of behavioural characteristics predictive of successful inclusion in mainstream education for children with autism spectrum disorders (ASD) and comparison students. Multiple regression analyses using behavioural ratings from parents, teachers and peers found some evidence for differential profiles predicting peer acceptance and rejection. High levels of peer-rated shyness significantly predicted social rejection in comparison students only. Parent-rated prosocial behaviour also differentially predicted social acceptance; high-levels of prosocial behaviour predicted acceptance in comparison students, but low-levels were predictive for students with ASD. These findings suggest that schools may seek to augment traditional social skills programmes with awareness raising about ASD among mainstream pupils to utilise peers’ apparent willingness to discount characteristics such as ‘shyness’

Language and reading development in children learning English as an additional language in primary school in England

Children learning English as an additional language (EAL) are a growing population of learners in English primary schools. These children begin school with differing levels of English language proficiency and tend to underperform in relation to their non‐EAL peers on measures of English oral language and reading. However, little work has examined the developmental trajectories of these skills in EAL learners in England. EAL learners and 33 non‐EAL peers in Year 4 (age 8–9 years) were assessed at three time points over 18 months on measures of oral language (vocabulary, grammar and listening comprehension), phonological processing (spoonerisms and rapid automatised naming) and reading skills (single‐word decoding and passage reading). At t1, EAL learners scored significantly lower than non‐EAL peers in receptive and expressive vocabulary (breadth but not depth), spoonerisms and passage reading accuracy. Contrary to previous research, no significant group differences were found in listening or reading comprehension skills. With the exception of passage reading accuracy, there was no evidence for convergence or divergence between the groups in rate of progress over time. After three years of English‐medium classroom instruction, EAL learners continue to underperform relative to their non‐EAL peers in breadth of English vocabulary knowledge. This discrepancy in vocabulary knowledge does not appear to narrow as a result of regular classroom instruction in the run up to the final stages of primary school, pinpointing vocabulary as a key target for intervention

A Disease of Pearl Millet in Zimbabwe Caused by Pantoea agglomerans

Necrosis at the leaf tips and margins of pearl millet (Pennisetum glaucum (L.) R. Br.) was observed in 1995 in a Pseudomonas syringae resistance screening nursery near Bulawayo, Zimbabwe. Straw-colored lesions with a chlorotic edge often extended the leaf length, and were atypical of the round spots, with a brown margin, caused by P. syringae (1). Bacteria were isolated from cut lesions macerated in water by dilution streaking onto King's medium B and nutrient agar. A gram-negative, nonfluorescent, fermentative, rod-shaped bacterium, forming yellow colonies on nutrient agar was consistently observed. Three pots of 10, 2-to 3-week-old seedlings of a susceptible cultivar, 852B, were inoculated with a 108 CFU per ml suspension from cultures by misting or injection into the whorl. In three experiments, the treatment and uninoculated control were incubated at 25°C and 95% relative humidity for 48 h before transfer to the greenhouse. The original symptoms of watersoaking at leaf tips and margins were observed after 4 days. Necrotic lesions surrounded by chlorotic tissue were observed a day later. Fluorescence on King's medium B, and levan, oxidase, potato-rot, arginine dihydrolase, 2-keto gluconate, nitrate reduction, gelatin, phenylalanine deaminase, and acid from starch tests were negative. Tobacco hypersensitivity, acid from sucrose and glycerol, aesculin hydrolysis, lipase, indole production, and growth on tetrazolium chloride were positive. The identification of the pathogen to the species level as Pantoea agglomerans (Ewing and Fife 1972) Gavini et al. 1989, formerly Erwinia herbicola, was by fatty acid analysis by the International Mycological Institute (Egham, Surrey, UK). P. agglomerans was recorded as a pathogen of pearl millet in India in 1958 (2)