2,269 research outputs found

    The influence of habitat quality on the foraging strategies of the entomopathogenic nematodes Steinernema carpocapsae and Heterorhabditis megidis

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    Entomopathogenic nematodes (EPN) are soil-transmitted parasites and their foraging strategies are believed to range from ‘ambush’ to ‘cruise’ foragers. However, research on their behaviour has not considered the natural habitat of these nematodes. We hypothesized that EPN behaviour would be influenced by soil habitat quality and tested this hypothesis using 2 EPN species Steinernema carpocapsae (an ‘ambusher’) and Heterorhabditis megidis (a ‘cruiser’) in 2 contrasting habitats, sand and peat. As predicted from previous studies, in sand most S. carpocapsae remained at the point of application and showed no taxis towards hosts, but in peat S. carpocapsae dispersed much more and showed a highly significant taxis towards hosts. H. megidis dispersed well in both media, but only showed taxis towards hosts in sand. In outdoor mesocosms in which both species were applied, S. carpocapsae outcompeted H. megidis in terms of host finding in peat, whereas the opposite was true in sand. Our data suggest that these 2 EPN may be habitat specialists and highlight the difficulties of studying soil-transmitted parasites in non-soil media

    Lagged relationships between a multilevel model of safety climate and employee safety outcomes

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    In Zohar’s Multilevel Model of Safety Climate (Zohar, 2000; 2003; Zohar & Luria, 2005), workers’ perceptions of their supervisor and manager’s commitment to safety are separately assessed and aggregated to the group and organisational level respectively. Treating safety climate as a multilevel construct has a number of conceptual and methodological advantages over the traditional single-level approach; however few researchers have adopted this practice and examined the cross-level or the lagged effects of safety climate.In the current thesis, the cross-level and lagged relationships safety climate has with safety outcomes was investigated through the use of a recently developed multilevel safety climate survey in the Australian oil and gas context. Data was collected over a two year period in a single organisation. The survey consisted of three scales, separately examining manager, supervisor, and co-worker commitment to safety. Safety outcomes were operationalized as self-reported near misses and injuries.The assessment of cross-level and lagged relationships involved a number of analyses, distributed across five objectives. In Objective One the factorial validity of the scales was assessed using confirmatory factor analysis. In Objective Two the cross-sectional criterion validity of the scales was examined using multilevel logistic regression in order to determine whether commitment to safety at each level of the organisation was associated with safety outcomes. In Objective Three, the predictive validity of each scale was assessed using multilevel Poisson regression in order to determine whether safety climate scores in Year One were predictive of safety outcomes in Year Two. In Objective Four, a series of path models were compared using path analysis in order to examine cross-level relationships between manager, supervisor, and co-worker commitment to safety. This analysis allowed the replication of Zohar and Luria’s (2005) findings, and could determine whether Zohar’s model could be extended to include perceptions of co-workers. In Objective Five, comparisons were made between safety climate operationalized at the individual and aggregate level, given the inconsistent labelling of safety climate at both levels of analysis despite the possibility that they may be distinct constructs.While all three scales demonstrated acceptable factorial validity, only the supervisor and manager scales provided evidence of criterion and predictive validity through significant associations with self-reported near misses. Path model comparisons provided support for Zohar’s Multilevel Model of Safety Climate and further suggested that co-workers were of lesser importance in promoting safety compared to supervisors and managers.Comparisons between safety climate operationalized at the individual and aggregate level demonstrated that level of analysis did affect that pattern of relationships between safety climate and self-reported near misses. While aggregated co-worker safety climate was the weakest predictor of self-reported near misses, individual level co-worker safety climate was the strongest predictor even after controlling for higher level variance. Analyses further indicated that individual level co-worker safety climate mediated the relationship between aggregated supervisor safety climate and individual level self-reported near misses.While replication of these findings is necessary, the results overall supported Zohar’s Multilevel Model of Safety Climate and suggested that the model could be extended to include individual level perceptions of co-workers. Results also indicated that level-of-analysis has a potentially important effect on the pattern of relationships between safety climate and safety outcomes

    Reducing inappropriate antibiotics prescribing: The role of online commentary on physical examination findings

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    Objective: This study investigates the relationship of ‘online commentary’(contemporaneous physician comments about physical examination [PE] findings) with (i) parent questioning of the treatment recommendation and (ii) inappropriate antibiotic prescribing. Methods: A nested cross-sectional study of 522 encounters motivated by upper respiratory symptoms in 27 California pediatric practices (38 pediatricians). Physicians completed a post-visit survey regarding physical examination findings, diagnosis, treatment, and whether they perceived the parent as expecting an antibiotic. Taped encounters were coded for ‘problem’ online commentary (PE findings discussed as significant or clearly abnormal) and ‘no problem’ online commentary (PE findings discussed reassuringly as normal or insignificant). Results: Online commentary during the PE occurred in 73% of visits with viral diagnoses (n = 261). Compared to similar cases with ‘no problem’ online commentary, ‘problem’ comments were associated with a 13% greater probability of parents uestioning a non-antibiotic treatment plan (95% CI 0-26%, p = .05,) and a 27% (95% CI: 2-52%, p < .05) greater probability of an inappropriate antibiotic prescription. Conclusion: With viral illnesses, problematic online comments are associated with more pediatrician-parent conflict over non-antibiotic treatment recommendations. This may increase inappropriate antibiotic prescribing. Practice implications: In viral cases, physicians should consider avoiding the use of problematic online commentary

    Scaffold searching: automated identification of similar ring systems for the design of combinatorial libraries

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    Rigid ring systems can be used to position receptor-binding functional groups in 3D space and they thus play an increasingly important role in the design of combinatorial libraries. This paper discusses the use of shape-similarity methods to identify ring systems that are structurally similar to, and aligned with, a user-defined target ring system. These systems can be used as alternative scaffolds for the construction of a combinatorial library

    Ecohydraulic modelling of anabranching rivers

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    In this paper we provide the first quantitative evidence of the spatial complexity of habitat diversity across the flow regime for locally anabranching channels, and their potential increased biodiversity value in comparison to managed single-thread rivers. Ecohydraulic modelling is used to provide evidence for the potential ecological value of anabranching channels. Hydraulic habitat (biotopes) of an anabranched reach of the River Wear at Wolsingham, UK is compared with an adjacent artificially straightened single-thread reach downstream. 2D hydraulic modelling was undertaken across the flow regime. Simulated depth and velocity data were used to calculate Froude number (Fr) index; known to be closely associated with biotope type, allowing biotope maps to be produced for each flow simulation using published Fr limits. The gross morphology of the anabranched reach appears to be controlling flow hydraulics, creating a complex and diverse biotope distribution at low and intermediate flows. This contrasts markedly with the near uniform biotope pattern modelled for the heavily modified single-thread reach. As discharge increases the pattern of biotopes altered to reflect a generally higher energy system, interestingly, however, a number of low energy biotopes were activated through the anabranched reach as new sub-channels became inundated and this process is creating valuable refugia for macroinvertebrates and fish, during times of flood. In contrast, these low energy areas were not seen in the straightened single thread reach. Model results suggest that anabranched channels have a vital role to play in regulating flood energy on river systems and in creating and maintaining hydraulic habitat diversity

    Memory in Interaction: An Analysis of Repeat Calls to a Home Birth Helpline

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    Drawing on a corpus of 80 calls to a Home Birth helpline, we use conversation analysis to analyze how callers and call takers display to one another that they are talking for a second or subsequent time. We focus in particular on the role of memory in these interactions. We show how caller and call taker are oriented to remembering at the beginning of calls as displayed in what we call the recognition-solicit pre-sequence, how participants are oriented to issues of forgetting and remembering during the course of repeat calls, and how remembering and forgetting are made manifest in interaction. Our analysis shows how the human capacity to remember and propensity to forget have reverberating implications in calling for help

    Culture or communicative conflict? : The analysis of equivocation in broadcast Japanese political interviews

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    The focus of this article is on equivocation in Japanese televised interviews, broadcast over a 14-month period in 2012-2013 (before and after the general election of December 16, 2012). An analysis was conducted of responses to questions by three different groups (national politicians, local politicians, and nonpoliticians). Results showed a striking level of equivocation by both national and local politicians, who together equivocated significantly more than nonpoliticians. Furthermore, national level Diet members equivocated significantly more than local politicians, and both coalition groupings when in power were significantly more likely to equivocate than when in opposition. The results were interpreted in terms of the situational theory of communicative conflict and also in terms of cultural norms characteristic of Japanese politics and society. The failure to consider the role of such norms, it is proposed, represents an important omission in the original theory of equivocation

    Paraphrases and summaries: A means of clarification or a vehicle for articulating a preferred version of student accounts?

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    The use of group discussions as a means to facilitate learning from experiences is well documented in adventure education literature. Priest and Naismith (1993) assert that the use of the circular discussion method, where the leader poses questions to the participants, is the most common form of facilitation in adventure education. This paper draws on transcripts of facilitation sessions to argue that the widely advocated practice of leader summaries or paraphrases of student responses in these sessions functions as a potential mechanism to control and sponsor particular knowledge(s). Using transcripts from recorded facilitation sessions the analysis focuses on how the leader paraphrases the students’ responses and how these paraphrases or ‘formulations’ function to modify or exclude particular aspects of the students’ responses. I assert that paraphrasing is not simply a neutral activity that merely functions to clarify a student response, it is a subtle means by which the leader of the session can, often inadvertently or unknowingly, alter the student’s reply with the consequence of favouring particular knowledge(s). Revealing the subtle work that leader paraphrases perform is of importance for educators who claim to provide genuine opportunities for students to learn from their experience
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