1,227 research outputs found

    Ecological values of Hamilton urban streams (North Island, New Zealand): constraints and opportunities for restoration

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    Urban streams globally are characterised by degraded habitat conditions and low aquatic biodiversity, but are increasingly becoming the focus of restoration activities. We investigated habitat quality, ecological function, and fish and macroinvertebrate community composition of gully streams in Hamilton City, New Zealand, and compared these with a selection of periurban sites surrounded by rural land. A similar complement of fish species was found at urban and periurban sites, including two threatened species, with only one introduced fish widespread (Gambusia affinis). Stream macroinvertebrate community metrics indicated low ecological condition at most urban and periurban sites, but highlighted the presence of one high value urban site with a fauna dominated by sensitive taxa. Light-trapping around seepages in city gullies revealed the presence of several caddisfly species normally associated with native forest, suggesting that seepage habitats can provide important refugia for some aquatic insects in urban environments. Qualitative measures of stream habitat were not significantly different between urban and periurban sites, but urban streams had significantly lower hydraulic function and higher biogeochemical function than periurban streams. These functional differences are thought to reflect, respectively, (1) the combined effects of channel modification and stormwater hydrology, and (2) the influence of riparian vegetation providing shade and enhancing habitat in streams. Significant relationships between some macroinvertebrate community metrics and riparian vegetation buffering and bank protection suggest that riparian enhancement may have beneficial ecological outcomes in some urban streams. Other actions that may contribute to urban stream restoration goals include an integrated catchment approach to resolving fish passage issues, active reintroduction of wood to streams to enhance cover and habitat heterogeneity, and seeding of depauperate streams with native migratory fish to help initiate natural recolonisation

    Arnotts Blending Project

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    Established and supported under the Australian Government’s Cooperative Research Centre Progra

    Seasonality and predictability shape temporal species diversity

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    Temporal environmental fluctuations, such as seasonality, exert strong controls on biodiversity. While the effects of seasonality are well known, the predictability of fluctuations across years may influence seasonality in ways that are less well understood. The ability of a habitat to support unique, non‐nested assemblages of species at different times of the year should depend on both seasonality (occurrence of events at specific periods of the year) and predictability (the reliability of event recurrence) of characteristic ecological conditions. Drawing on tools from wavelet analysis and information theory, we developed a framework for quantifying both seasonality and predictability of habitats, and applied this using global long‐term rainfall data. Our analysis predicted that temporal beta diversity should be maximized in highly predictable and highly seasonal climates, and that low degrees of seasonality, predictability, or both would lower diversity in characteristic ways. Using stream invertebrate communities as a case study, we demonstrated that temporal species diversity, as exhibited by community turnover, was determined by a balance between temporal environmental variability (seasonality) and the reliability of this variability (predictability). Communities in highly seasonal mediterranean environments exhibited strong oscillations in community structure, with turnover from one unique community type to another across seasons, whereas communities in aseasonal New Zealand environments fluctuated randomly. Understanding the influence of seasonal and other temporal scales of environmental oscillations on diversity is not complete without a clear understanding of their predictability, and our framework provides tools for examining these trends at a variety of temporal scales, seasonal and beyond. Given the uncertainty of future climates, seasonality and predictability are critical considerations for both basic science and management of ecosystems (e.g., dam operations, bioassessment) spanning gradients of climatic variability

    Robust analysis of prokaryotic pangenome gene gain and loss rates with Panstripe

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    Horizontal gene transfer (HGT) plays a critical role in the evolution and diversification of many microbial species. The resulting dynamics of gene gain and loss can have important implications for the development of antibiotic resistance and the design of vaccine and drug interventions. Methods for the analysis of gene presence/absence patterns typically do not account for errors introduced in the automated annotation and clustering of gene sequences. In particular, methods adapted from ecological studies, including the pangenome gene accumulation curve, can be misleading as they may reflect the underlying diversity in the temporal sampling of genomes rather than a difference in the dynamics of HGT. Here, we introduce Panstripe, a method based on generalized linear regression that is robust to population structure, sampling bias, and errors in the predicted presence/absence of genes. We show using simulations that Panstripe can effectively identify differences in the rate and number of genes involved in HGT events, and illustrate its capability by analyzing several diverse bacterial genome data sets representing major human pathogens.Peer reviewe

    How was the intern year?: self and clinical assessment of four cohorts, from two medical curricula

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    BACKGROUND Problem-based curricula have provoked controversy amongst educators and students regarding outcome in medical graduates, supporting the need for longitudinal evaluation of curriculum change. As part of a longitudinal evaluation program at the University of Adelaide, a mixed method approach was used to compare the graduate outcomes of two curriculum cohorts: traditional lecture-based ‘old’ and problem-based ‘new’ learning. METHODS Graduates were asked to self-assess preparedness for hospital practice and consent to a comparative analysis of their work-place based assessments from their intern year. Comparative data were extracted from 692 work-place based assessments for 124 doctors who graduated from the University of Adelaide Medical School between 2003 and 2006. RESULTS Self-assessment: Overall, graduates of the lecture-based curriculum rated the medical program significantly higher than graduates of the problem-based curriculum. However, there was no significant difference between the two curriculum cohorts with respect to their preparedness in 13 clinical skills. There were however, two areas where the cohorts rated their preparedness in the 13 broad practitioner competencies as significantly different: problem-based graduates rated themselves as better prepared in their ‘awareness of legal and ethical issues’ and the lecture-based graduates rated themselves better prepared in their ‘understanding of disease processes’. Work-place based assessment: There were no significant differences between the two curriculum cohorts for ‘Appropriate Level of Competence’ and ‘Overall Appraisal’. Of the 14 work-place based assessment skills assessed for competence, no significant difference was found between the cohorts. CONCLUSIONS The differences in the perceived preparedness for hospital practice of two curriculum cohorts do not reflect the work-place based assessments of their competence as interns. No significant difference was found between the two cohorts in relation to their knowledge and clinical skills. However results suggest a trend in ‘communication with peers and colleagues in other disciplines’ (χ2 (3, N = 596) =13.10, p = 0.056) that requires further exploration. In addition we have learned that student confidence in a new curriculum may impact on their self-perception of preparedness, while not affecting their actual competence.Gillian Laven, Dorothy Keefe, Paul Duggan, and Anne Tonki

    The effect of an interactive tutorial on the prescribing performance of senior medical students

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    Objectives: To evaluate the effectiveness of small group tutorials in teaching senior medical students the requirements of prescription writing. Design: Random allocation to interactive tutorial or didactic lecture with blinded evaluation. Subjects: All 1999 6th year medical students, the University of Adelaide. Results: The Tutorial Attenders (mean 13.3, SD 2.6) performed significantly better than the Lecture Group (mean12.2, SD 3.0) p=0.041 and the Non-attenders (mean10.7, SD 3.1) p=<0.001. The 13 individual OSCE items formed four logical subgroups, and the Tutorial Attenders performed significantly better in Prescription Writing in all comparisons. Conclusion: A single, one-hour interactive tutorial is likely to be the minimum amount of intervention that will be effective in improving prescribing skills.Anne L Tonkin, David Taverner, Jenny Latte, Christopher Doeck
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