Extremes in worldwide geomagnetic activity

Geomagnetic storms pose a hazard to many modern technologies. Therefore understanding how severe such storms could be is important to a wide range of space weather data and forecast end-users. Extreme value statistical (EVS) methods are therefore applied to a global set of geomagnetic observatory data to determine the one in 100 and one in 200 year extreme values in the north, east and horizontal field strengths and their time rates-of-change. We use one-minute digital data from geographically widely distributed observatories with typically a few decades of digital operations. Individual generalised Pareto distribution functions are fitted to the tail of each observatory data distribution, above some threshold marking the onset of extreme activity for that location. We discuss the return levels, for the one in 100 and one in 200 year events, with respect to the geographical distribution of the observatories, the proximity to auroral and equatorial electrojets and compare results with a separate EVS study of European-only magnetic observatory dat

Tabusintac Bay (New Brunswick, Canada): an important spring migratory stopover for Atlantic Brant (Branta bernicla hrota)

Atlantic Brant (Branta bernicla hrota) is an Arctic-breeding migratory waterfowl that relies heavily on Common Eelgrass (Zostera marina) for food during migration and overwintering. Although the abundance of Atlantic Brant along the coasts of the Maritime provinces has declined drastically over the past decades, some flocks continue to migrate through the area in spring. Here, we present field observations of Atlantic Brant spring staging in the Tabusintac Bay, New Brunswick, Canada. We surveyed the Tabusintac Bay seven times between 26 May and 6 June 2018. We observed a maximum daily count of 1259 individuals, which is comparable to high counts from the 1970s. These spring surveys indicate the continuing importance of Tabusintac Bay to Atlantic Brant for spring staging. There is a pressing need to increase monitoring and research in the region and to preserve or enhance the quality of the area for spring staging brant

Lucerne for Acid Soils: A Field Evaluation of Early Generation Aluminium Tolerant Genotypes

The development of lucerne germplasm tolerant of acidic soil conditions has long been a research objective of international significance. Many initiatives have previously failed to produce genotypes with adequate improvement in tolerance to be deemed economically viable and as a consequence, still no cultivar of lucerne exists that has improved adaptation to acidic soils. An Australian research program spanning the previous decade sought to redress this issue by developing lucerne genotypes with significantly enhanced tolerance to aluminium (Al) toxicity. Using recurrent selection in hydroponic solution culture, populations selected comprised individuals which displayed enhanced seedling root growth following a pulse of Al toxic solution (Scott et al. 2008). A subsequent pot experiment showed that these populations exhibited up to 40% increase in seedling root length when grown in an acidic soil with high Al concentration, though there was a differential response observed between the elite populations (Hayes et al. 2011). The current study tested the hypothesis that lucerne establishment in the field would be higher in populations selected in high Al solution culture when grown in an acidic soil environment

Book Reviews

The following publications have been reviewed by the authors;The Good Technology Guide 1994 - reviewed by Danny OwenObjects and Images: Studies in Design and Advertising - reviewed by Prof. P. RobertsClassroom Pedagogy and Primary Practice - reviewed by Alan CrossBasic Electronics For Tomorrow's World - reviewed by Allan TruemanBeyond The Core Curriculum - reviewed by  CD. SnellFood For Thought - reviewed by Rhona Humphrie

I Just Want To Be Me, Authentically : Identity Shifting Among Racially and Ethnically Diverse Young Adults

Identity shifting represents a common but complex social, behavioral, and cognitive phenomenon. However, some forms of identity shifting originate in response to structural, institutional, and interpersonal marginalization enacted on lower status groups, such as people of color in the United States. The current study investigated ways young adults from diverse ethnic/racial groups discussed shifting to fit in with White Americans (a dominant group) in the United States and their own ethnic/racial group (a minoritized group) and elucidated self-reported motivations for shifting. Participants consisted of 764 young adults (ages = 18–23) recruited from two large public universities in the Southeast and Southwest regions of the United States. The majority of participants identified as Black/African American (41%), Asian/Asian American (27%), or Hispanic/Latinx (22%). Analysis of participants’ qualitative responses identified six types of shifts and two motivations for shifting. The shifts included: behavioral, linguistic, cognitive, physical, food, and affect. Motivations for shifting focused on avoiding risks and obtaining rewards. The discussion offers interpretation of the results and recommendations for future research on identity shifting

An assessment of Pc5 pulsations observed during the Carrington Storm

The Greenwich observatory magnetogram for 2nd September 1859 shows prolonged periods of ULF Pc5-like pulsations, most likely global Pc5s driven by the solar wind during the recovery phase of the storm. Unlike the very rapid and presumably very high amplitude variations that are off scale during the peak of the magnetic storm on 1st September 1859, the pulsation events have been well preserved in the records of the time. (Further information on and images of the scanned Carrington magnetograms can be found at www.bgs.ac.uk/data/Magnetograms/home.html.) We therefore try to put the measured amplitude and duration of the Carrington Pc5 pulsations into some context by analysing them in relation to modern day records. For this we analyse Pc5 pulsations occurring in data from the Hartland, UK observatory, which is geographically close to Greenwich, and Wingst observatory, Germany. Wingst, in particular, has a geomagnetic latitude believed to be closer to that of Greenwich at the time of the Carrington storm (around 50 degrees north). For both observatories there are complete records from the early 1980s to the present day, providing a continuous data set, over three decades, containing many severe storms from the recent past. We use 1-minute mean horizontal component field data that are filtered in the Pc5 150-600 second pass band, and in other pass bands for comparison, by means of an 8th order Butterworth filter. By means of various measures (e.g. amplitude, duration, root-mean-square over the day, and others) we try to determine how atypical the Carrington pulsations were. We discuss issues such as how the differing magnetometer responses to high frequency magnetic variations, ‘then’ and ‘now’, may affect the interpretation of results across more than 150 years and how the results depend on time of day

Compiler and Runtime Support for Programming in Adaptive Parallel Environments

For better utilization of computing resources, it is important to consider parallel programming environments in which the number of available processors varies at runtime. In this paper, we discuss runtime support for data parallel programming in such an adaptive environment. Executing programs in an adaptive environment requires redistributing data when the number of processors changes, and also requires determining new loop bounds and communication patterns for the new set of processors. We have developed a runtime library to provide this support. We discuss how the runtime library can be used by compilers of HPF-like languages to generate code for an adaptive environment. We present performance results for a Navier-Stokes solver and a multigrid template run on a network of workstations and an IBM SP-2. Our experiments show that if the number of processors is not varied frequently, the cost of data redistribution is not significant compared to the time required for the actual computation. Overall, our work establishes the feasibility of compiling HPF for a network of non-dedicated workstations, which are likely to be an important resource for parallel programming in the future. (Also cross-referenced as UMIACS-TR-95-83

Improving the Feeding Value of Dryland Lucerne in Australia

Lucerne (Medicago sativa L.) is the most widely grown perennial legume species in southern Australia. Within Australian farming systems it plays an important role in the provision of high-quality feed for livestock, nitrogen fixation and dewatering soils to reduce watertable recharge and dryland salinity (Cocks 2001). The majority of lucerne varieties have been developed for the areas with high rainfall or supplementary irrigation. The new challenge is to develop lucerne cultivars specifically for dryland mixed farming systems in temperate and mediterranean climate zones (Humphries and Auricht, 2001). Persistence in these environments and feeding value to sheep are critical selection traits. In this paper we compare nutritive traits of 35 commercial and experimental accessions of lucerne, sampled during the vegetative phase, and test the hypothesis that there will be significant differences between the accessions for in vitro dry matter digestibility (DMD), crude protein (CP), acid detergent fibre (ADF), neutral detergent fibre (NDF) and hemicellulose