3,245 research outputs found
Semantic and self-referent encoding techniques and recall of meanings of unfamiliar adjectives
In order to test the efficacy of levels of processing on memory, recall of unfamiliar adjectives among five encoding groups: a) semantic, b) self-reference specific, c) self-reference general, d) semantic (plural), and e) self-reference specific (plural) was examined. Introductory psychology students at the University of Richmond viewed twenty unfamiliar adjectives and definitions for forty-five seconds each, followed by a five minute distractor task and a seven minute test for recall of the definitions. A second seven minute recall test was administered one week later. There were no significant differences in recall between groups, but a significant effect of time upon recall over retention intervals was indicated, Q. \u3c .01, and simple effects revealed a significant drop in retention for each group between the two retention intervals. It was proposed that the lack of significant differences in recall among encoding groups was the result of such factors as low subject motivation, ambiguity of encoding instructions, informal experimental setting, and inappropriateness of target words. These factors were recommended as points for consideration in future studies
Monitoring of Cape Vulture (Gyps coprotheres) breeding colonies in the Magaliesberg, South Africa: 2007-2009
Cape Vultures (Gyps coprotheres) at three colonies, Skeerpoort, Roberts’ Farm and Nooitgedacht, in the Magaliesberg range in South Africa were monitored during 2007- 2009 to determine their breeding success and population trends. All three colonies showed high levels of breeding success, but while Nooitgedacht and Roberts’ Farm supported increased numbers of breeding pairs over the monitoring period, Skeerpoort (the largest) showed a dramatic decline between 2008 and 2009, the cause of which is unknown.Keywords: Monitoring, breeding colonies, Magaliesberg, South Africa, Cape Vulture, Gyps coprothere
Synthesis and characterization of amorphous astrominerals
Abstract only availableAsymptotic Giant Branch (AGB) stars are the main contributors of solid material (dust) to the interstellar medium. The dust forms as gas escaping from the star cools and condenses to form a circumstellar dust shell. Around oxygen-rich stars, most of the dust particles are silicates, but important questions remain about which minerals are formed and whether the grains are crystalline or amorphous (glassy). Dust grains that form below the glass transition temperature (Tg) of a particular mineral should be amorphous, while those that form much above Tg should be crystalline. The most refractory silicates predicted to form are members of the Melilite group of minerals, whose end-members are Gehlenite (Ca2Al2SiO7), Sodium Melilite (CaNaAlSi2O7) and Åkermanite (Ca2MgSiO7). Synthetic glasses corresponding to these end-member compositions were synthesized from oxide and carbonate powders by melting in Pt crucibles in a muffle furnace at temperatures up to 1650˚C. The viscosity of the melts was measured by the parallel-plate technique in the temperature range 655 to 900˚C, over the viscosity range 2x107 to 91012 Pa s. The viscosity-temperature data were interpolated to determine Tg for each glass, taken to be the temperature at which the viscosity is 1012 Pa s. Two naturally occurring mineral samples, of åkermanite and gehlenite, were also melted. At higher temperatures and lower viscosities than about 108 Pa s, crystallization is expected to be rapid relative to the timescale of cooling in circumstellar dust shells. Our experimentally determined glass transition temperatures therefore provide constraints on the nature (crystalline vs amorphous) of several refractory astrominerals predicted to be found in these shells. Future studies of these glasses will include infrared spectroscopy, in order to better interpret astronomical spectra and test for the presence of amorphous dust with these compositions. The results will be used to test competing models for circumstellar dust formation.Missouri Academy at Northwest Missouri State Universit
The distribution of Bibionidae (Diptera) in Scotland
We review the material of the family Bibionidae from Scotland in the Natural History Museum, London and the National Museums of Scotland, Edinburgh, as well as some material from other collections and published records from the SIRI (Scottish Insect Records Index). Eleven species of the genus Bibio Geoffroy, 1762 and four species in the genus Dilophus Meigen, 1803 have been collected in Scotland. We review the distribution and ecology of each species and present maps of records. Previous Scottish records of Bibio hortulanus (Linnaeus, 1758) and B. reticulatus Loew, 1846 are deemed to be most likely erroneous. Additionally, we have not found any specimens confirming the literature record of Bibio venosus (Meigen, 1804), but we believe this record is most likely correct since this species is distinctive and well defined with no substantial confusion about its identity. There is also a recent record of Dilophus humeralis Zetterstedt, 1850 which we have not been able to confirm. The following species have unambiguous records from Scotland: Bibio clavipes Meigen, 1818; B. ferruginatus (Linnaeus, 1758); B. johannis (Linnaeus, 1767); B. lanigerus Meigen, 1818; B. leucopterus (Meigen, 1804); B. longipes Loew, 1864; B. marci (Linnaeus, 1758); B. nigriventris Haliday, 1833; B. pomonae (Fabricius, 1775); B. varipes Meigen, 1830; Dilophus bispinosus Lundström, 1913; D. febrilis (Linnaeus, 1758); D. femoratus Meigen, 1804
Exposure factors leading to establishment of OJD infection and clinical disease : epidemiology of OJD-1.
This study was conducted in order to provide answers for owners of OJD-infected sheep flocks who wish to minimise the economic and biological impact of the disease on their sheep enterprises. The study has demonstrated that careful management of young sheep can reduce the level of OJD in the flock and reduce the death rate. One key finding is that steps taken to limit the degree of exposure of pre-weaned lambs to infection from pastures will lead to reduced rates of severe infection in those sheep in later years. A second key finding is that continuous exposure to OJD bacteria throughout early life results in higher infection rates than exposure which is limited to either the pre-weaning or the post-weaning period alone. A critical factor in management is to provide ‘low risk’ pastures to young sheep at weaning to give them a break from exposure to infection which occurs in the lambing paddocks. We also found that weaned lambs and adult ewes remain susceptible to infection and that there is little evidence for an age-related resistance to OJD
Exposure factors leading to establishment of OJD infection and clinical disease : epidemiology of OJD-1.
This study was conducted in order to provide answers for owners of OJD-infected sheep flocks who wish to minimise the economic and biological impact of the disease on their sheep enterprises. The study has demonstrated that careful management of young sheep can reduce the level of OJD in the flock and reduce the death rate. One key finding is that steps taken to limit the degree of exposure of pre-weaned lambs to infection from pastures will lead to reduced rates of severe infection in those sheep in later years. A second key finding is that continuous exposure to OJD bacteria throughout early life results in higher infection rates than exposure which is limited to either the pre-weaning or the post-weaning period alone. A critical factor in management is to provide ‘low risk’ pastures to young sheep at weaning to give them a break from exposure to infection which occurs in the lambing paddocks. We also found that weaned lambs and adult ewes remain susceptible to infection and that there is little evidence for an age-related resistance to OJD
Prevalence of sustainability reporting practices of a sample of listed companies on established and emerging stock exchanges
The business sector has a substantial role in addressing current environmental issues and concerns. Consequently, there is a growing adoption of corporate sustainability principles and practices across all market sectors. This study examined four developed and four emerging stock markets and the sustainability reporting practices of the top 20 and bottom 20 companies in each. The results illustrate that the developed market sector was more advanced in its corporate sustainability reporting, both in the proportion of companies issuing a sustainability report (approximately 60 per cent) and the proportion of company webpages dedicated to sustainability reporting. This difference was largely due to the effect of the top 20 companies. There was little difference between developed and developing markets when only the bottom 20 companies were considered, of which less than one-third provided sustainability reports. These results show that sustainability reporting is prevalent in both developed and developing markets, especially among market leading companies, but that overall, most developing markets have some catching up to do
Identification of risk factors for OJD infection-level in sheep flocks.
The level of clinical disease experienced due to ovine Johne’s disease (OJD) appears to vary considerably between infected sheep flocks in Australia, even for flocks in the same locality that appear to have similar characteristics. This has led to speculation on the cause. Risk factors for the severity of OJD were identified in this project. They were related to some farming practices such as fertiliser application, as well as to flock management and soil type. In particular weaner management and nutrition of sheep to hogget stage were important factors that producers can optimise to reduce the impact of OJD. High soil fertility, organic matter and clay content were also important factors associated with higher levels of OJD. There was less OJD associated with sandy soils. Further research is required in order to determine how these soil characteristics affect the prevalence of OJD and how best to manage soil and pasture to mitigate the losses due to OJD
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