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Although there have been repeated calls for empirical evaluations focused on if and how the activities of Indigenous Education Units contribute to Indigenous student success at university, data demonstrating the outcomes of these activities remain scarce. As a first step in addressing this gap, a case study of the Kulbardi Aboriginal Centre is presented which documents the development and implementation of its student success strategy. Informed by research that identifies a range of different barriers and enablers of Indigenous student success, the strategy was built around a ‘whole-of-university’ approach which focuses on influencing across multiple levels of the university (governance and management, teaching and pedagogy and direct student support). The success of the strategy is described in relation to changes in Indigenous student retention and pass rates. The case study offers insight into the activities of an Indigenous Education Unit, which can inform future models of practice in this area and raise awareness of the need for more comprehensive and nuanced evaluation of Indigenous higher education initiatives.
This article presents an analysis of statements from Indigenous students in an Australian university that describe how they use supplementary tutors. The analysis provides some evidence that students use tutors for much more than the prescribed remedial purpose to assist with gaps in assumed academic knowledge and skills to prevent subject failures. Students also use tutors to access hidden knowledge and develop capabilities that assist their progress from dependence on assistance to independence in learning. Our analysis has implications for the conceptualisation and management of supplementary tutoring for Indigenous students.
The current change agenda to improve the persistently lower rates of access, participation and outcomes of Indigenous Australians in higher education is a broad one that attempts to address the complex range of contributing factors. A proposition in this paper is that the broad and longer-term focus runs the risk of distracting from the detailed considerations needed to improve support provisions for enrolled students in the immediate term. To bring more attention to this area of indicated change, we revisit ‘the gaps’ that exist between the performance of Indigenous and all other domestic students and the role that student support services have to play in improving retention and completion rates of enrolled Indigenous students. We outline some principles that can guide strategies for change in Indigenous undergraduate student support practices in Australian universities to respond to individual student needs in more effective and timely ways. These are illustrated using examples from the redevelopment of services provided by an Indigenous Education centre in a Go8 university, along with data gathered from our ARC study into Indigenous academic persistence in formal learning across three Australian universities.
The Perth Astronomy Research Group (PARG), consisting of members from Curtin University of Technology, Perth Observatory and the University of Western Australia, is in the process of developing an automated supernova search system, using the 61-cm Lowell-Perth reflector, a CCD camera and an 80386-based computer for image analysis. Computer control of the telescope and dome, a liquid-nitrogen-cooled CCD camera, and modified VISTA image analysis software will be completed in late 1990, allowing initial semi-automatic searching of external galaxies, together with CCD photometry of flare stars and newly discovered supernovae. Full-scale automation will be introduced subsequently, in collaboration with the Berkeley group. This paper describes the project, and reports on its current status.
Polycrystalline solutions of 0.6(Bi0.9La0.1)FeO3-0.4Pb(Ti1-xMnx)O3(BLF-PTM, x=0 and 0.01)have been fabricated by the so-gel process combined with a solid state reaction method. BLF-PTM exhibits the nonlinear dielectric and piezoelectric responses under applied fields. Rayleigh law has been used to evaluate the irreversible contribution of the domain walls movement to the nonlinear dielectric response. Rayleigh analysis reveals that a mechanism with no associated loss exists in the BLF-PTM of x=0.01. The real part piezoelectric coefficient of BLF-PTM linearly increases with increasing the electric fields. The dielectric and piezoelectric nonlinear coefficient of 0.17×10-3 m/V and 0.897 ×10-17 m2/V2 respectively are obtained for BLF-PTM of x=0.01,which are smaller than those of 0.22×10-3 m/V and 1.19 ×10-17 m2/V2 for BLF-PTM of x=0. Our results indicate that Mn doping increase the intrinsic piezoelectric properties of BLF-PTM reducing the extrinsic contributions to piezoelectric responses.
Interrupted mating methods were used to map the positions on the chromosome of genes for the utilization of acetamide, histidine and proline. An entry time of 22 min was found for a put marker determining the utilization of proline. Two groups of hut mutants were studied. Mutation hut-109 was located at 18 min and mutation hutU108, which results in a defect in urocanase activity, mapped at 28 min. hutU was shown by transduction with bacteriophage F116 to be linked to ser-3 but not to met-28 and ilv-202, giving a map order of hutU-ser-3-ilv-202-met-28.
The amidase genes were assigned an entry time of 65–75 min. A method is described for examining late entry markers by interrupted mating.
Mutants of Pseudomonas aeruginosa, which differed in amide growth phenotype from the wild-type strain, were subjected to genetic analysis using the generalized transducing phage F116. The map order of some mutational sites was determined by 3-factor crosses in which a mutation in the linked regulator gene amiR was used as the outside marker to determine the relative order of mutations in the amidase structural gene amiE. Acetamide-positive transductants were recovered in crosses between amidase-negative strains and strains PhB3(PAC377), V2(PAC353) and V5(PAC356) producing mutant amidases which hydrolyse phenylacetamide and valeramide but not acetamide. Some recombinants carried the mutation amiE16 determining the properties of the mutant B amidase produced by strain B6(PAC351) from which both PhB and V class mutants were derived, while other recombinants produced A amidase determined by the wild-type amiE gene.
Terrestrial environments differ from aquatic environments in terms of the extent and persistence of inundation, with the terrestrial world, of course, drier than the aquatic one. Despite this basic difference between aquatic and terrestrial environments, the survival and reproductive problems faced by bacteriophages in the terrestrial world, such as within soils, can be similar to those faced in aquatic habitats or, for that matter, can be similar to those faced in or on plants or animals. Indeed, to the extent that bacterial hosts grow in biofilms, it matters little — periodic desiccation aside — whether we think of these bacteria as inhabiting rivers, puddles, sediment, soil, or, alternatively, other organisms. Therefore, although this chapter concentrates on soil as the environment, we will review studies performed in various non-terrestrial environments, to the extent that they illuminate our understanding of phage ecology in the terrestrial world. We will briefly consider phage and bacterial host life histories as they are integrally associated, drawing themes together using relevant information derived from the study of associations and interactions between phages and prokaryotes in other environments to see what is consistent, possible, or improbable. In addition, we review common themes associated with phage-mediated horizontal (also described as lateral) gene transfer between bacteria (transduction) as it occurs in the wild.
How do bacteriophages exist in the hostile environments that their bacterial hosts inhabit? In most environments, from the desert to the mammalian gut, bacteria live for most of their existence in a starved state (Koch, 1971; Morita, 1997) where energy, carbon, and other resources are in scarce supply. Under such conditions we know that the latency period for phage infection lengthens, that the burst size is greatly reduced (Kokjohn et al., 1991), and that the half-life of virion infectivity (rate of decay) is short (Miller, 2006); yet total counts of virus-like particles present in environmental samples are high. Clearly bacteriophages have evolved strategies for surviving under these unfavorable conditions. As survival-enhancement strategies, many biological entities, from bears to bacteria, have evolved dormant states. During phage infection we recognize analogous dormant states as lysogeny and as pseudolysogeny. In this chapter we explore several aspects of the ecological consequences of these “reductive” infections.
In addition to the material presented here, we direct the reader to additional reviews considering lysogeny, pseudolysogeny, and phage infection of starved bacteria: Barksdale and Arden (1974), Ackermann and DuBow (1987), Schrader et al. (1997a), Robb and Hill (2000), and Miller and Ripp (2002). Related issues, especially of phage contribution to bacterial genotype and phenotype, are also considered in Chapters 11 and 14.
To provide estimates of horizontal gene transfer from transgenic
crops to indigenous soil bacteria, transformation frequencies were obtained
for naturally transformable Acinetobacter baylyi
BD413 using a chromosomally integrated plant transgene. The transgene
comprised sequences for two phenotypic markers: kanamycin resistance
(npt II) and green fluorescent protein
(gfp), expressed from their own bacterial
promoters. Recipient bacteria carried a copy of these two genes, with
deletions in their 3'-termini abolishing the marker activity, these genes
were integrated into a 16S rRNA gene in the bacterial chromosomal genome or
carried on a broad host range plasmid. Successful recombination between the
plant transgene and the bacterial genome resulted in restoration of the
markers, allowing detection through antibiotic selection and fluorescence.
Transformation parameters of increasing complexity, without any enrichment
steps, were used to approach the field conditions, while still obtaining
measurable transformation frequencies. In pure culture filter experiments,
transformation was detected using ground, chopped and whole leaves, as well
as whole sterile seedlings, and ground roots. In sterile soil microcosms,
transformation was detected using pure plant DNA (3.6 × 10-8
transformants per recipient) and ground leaves (2.5 × 10-11).
Transformation was also detected for the first time in non-sterile soil
using pure plant DNA (5.5 × 10-11). Since the same constructs
were used throughout, these data allow predictions of even more complex
environmental systems where measurable frequencies are not easily
RecA-mediated recombination requires regions of homology between
donor and recipient DNA for successful integration. This paper investigates
the effect of the relationship between the length of gene-sized inserts
(434, 733, 2228 and 2400 bp) and flanking sequence homology (100 –
ca. 11 000 bp) on transformation frequency in
strain BD413. Both insert size and size of the homologous region were
varied, which improves on previous studies that kept insert size constant
and varied only the homologous flank size. Transfer frequency of a
non-homologous single small gene for gentamicin resistance
(aac(3)I; 773 bp) was increased 18-fold when
flanking homology was changed from about 2000 bp to 8000 bp, but was
reduced 234-fold when two genes were inserted
(nptII-gfp; 2400 bp)
between similar homologous regions. To investigate the effect of smaller
regions of flanking homology (100 – 2000 bp), a partial
(434 bp) was restored. This confirmed that a minimum of 500 bp on each flank
was required for transformation to be affected by flanking homology. The
data obtained allowed development of a multiple regression equation to
predict transformation frequency from homology, insert size and total
fragment size for gene insertions. We also show that the ratio of
flanking homology to insert size and not the total size of donor DNA is the
most important variable determining transformation frequency. The
equation developed was consistent with results previously reported by
others, and so will be useful when using A. baylyi as a model for gene transfer by transformation in the
laboratory, environment and for biosafety.
We consider the differential game associated with robust control of a
system in a compact state domain, using Skorokhod dynamics on the
boundary. A specific class of problems motivated by queueing network control
is considered. A constructive approach to the Hamilton-Jacobi-Isaacs
equation is developed which is based on an appropriate family of
extremals, including boundary extremals for which the Skorokhod
dynamics are active. A number of technical lemmas and a structured
verification theorem are formulated to support the use of this
technique in simple examples. Two examples are considered which
illustrate the application of the results. This extends previous work
by Ball, Day and others on such problems, but with a new emphasis on
problems for which the Skorokhod dynamics play a critical role.
Connections with the viscosity-sense oblique derivative conditions of
Lions and others are noted.
Many snow models have been developed for various applications such as hydrology, global atmospheric circulation models and avalanche forecasting. The degree of complexity of these models is highly variable, ranging from simple index methods to multi-layer models that simulate snow-cover stratigraphy and texture. In the framework of the Snow Model Intercomparison Project (SnowMIP), 23 models were compared using observed meteorological parameters from two mountainous alpine sites. The analysis here focuses on validation of snow energy-budget simulations. Albedo and snow surface temperature observations allow identification of the more realistic simulations and quantification of errors for two components of the energy budget: the net short- and longwave radiation. In particular, the different albedo parameterizations are evaluated for different snowpack states (in winter and spring). Analysis of results during the melting period allows an investigation of the different ways of partitioning the energy fluxes and reveals the complex feedbacks which occur when simulating the snow energy budget. Particular attention is paid to the impact of model complexity on the energy-budget components. The model complexity has a major role for the net longwave radiation calculation, whereas the albedo parameterization is the most significant factor explaining the accuracy of the net shortwave radiation simulation.
Nose ringing is widely used in conventional outdoor pig production as the only reliable method of preventing sows destroying pasture by rooting (Edwards et al., 1998), but is prohibited by some organic sector bodies as it inhibits the sows’ behaviour. Some organic producers use a rotation policy in which the sows are moved to fresh pasture about three times a year, after green cover has been destroyed. As well as limiting nutrient leaching, frequent movement also limits parasite build-up in a system which prohibits the routine use of anthelmintics. However, it has a high labour demand. An alternative strategy is to maintain the sows on a larger area for the whole year. This abstract presents initial data on comparison of the two systems regarding annual pattern of pasture damage by sows.
The critically endangered Sichuan Hill-partridge Arborophila rufipectus occupies a restricted range in south-central China. Field surveys within this range were undertaken using line transects in 1996 and 1997. Calling males were recorded from nine subtropical forest tracts within an area totalling 1,793 km2 and consisting of primary, natural secondary and replanted broadleaf forest between 1,100 and 2,235 m elevation. The only sightings obtained were in primary forest. The mean density of calling males estimated from data collected during transect surveys was 0.48 ± 0.06 and 0.24 ± 0.16 calling birds km−2 in 1996 and 1997 respectively. There was no difference in density estimates for calling males between primary forest and secondary/replanted broadleaf forest. The principal threat to the continued survival of the species is clear-felling of primary forest, but clear-felled areas are often replanted with native broadleaf trees and records of Sichuan Hill-partridge calls in such plantations offers hope for its future survival. Forest management should be modified to make forestry practices more sympathetic to the conservation of the Sichuan Hill-partridge.