1000 resultados para plant–water relations


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This study examined whether high nutrient concentrations associated with leaf-cutting ant nests influence plant growth and plant water relations in Amazon rain forests. Three nests of Atta cephalotes were selected along with 31 Amaioua guianensis and Protium sp. trees that were grouped into trees near and distant (>10 m) from nests. A 15N leaf-labelling experiment confirmed that trees located near nests accessed nutrients from nests. Trees near nests exhibited higher relative growth rates (based on stem diameter increases) on average compared with trees further away; however this was significant for A. guianensis (near nest 0.224 y−1 and far from nest 0.036 y−1) but not so for Protium sp. (0.146 y−1 and 0.114 y−1 respectively). Water relations were similarly species-specific; for A. guianensis, near-nest individuals showed significantly higher sap flow rates (16 vs. 5 cm h−1), higher predawn/midday water potentials (−0.66 vs. −0.98 MPa) and lower foliar δ13C than trees further away indicating greater water uptake in proximity to the nests while the Protium sp. showed no significant difference except for carbon isotopes. This study thus shows that plant response to high nutrient concentrations in an oligotrophic ecosystem varies with species. Lower seedling abundance and species richness on nests as compared with further away suggests that while adult plants access subterranean nutrient pools, the nest surfaces themselves do not encourage plant establishment and growth.

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This paper looks at employer expectations of advertising and public relations graduates seeking an entry level position. For employers in both disciplines, the top three priorities are the same generic skills – communications skills, personality traits and strategic or analytical thinking. However, some significant differences were observed, with PR practitioners assigning more importance to practical aspects such as experience in the field and internships. Public relations employers also tend to think that advertising graduates require less strategic skills than public relations graduates. Advertising practitioners generally considered the skills of entry level recruits to be more consistent across the two disciplines.

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This article examines the relevance of James Grunig and Todd Hunt’s (1984) theories to public relations practitioners’ roles in south east Queensland schools. It focuses in particular on the two-way symmetric model in this context. The geographical boundaries of the research mean that this article is intended primarily as an exploratory, descriptive analysis of a specific area rather than an exhaustive treatise on the general topic of public relations in Australian schools. However, it is hoped that it will prove useful in identifying bases for further study and discussion.

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The intention of this paper is to further the discussion around the development of theories of public relations by introducing to the mix the concept of the Other from the field of cultural studies. The development of discipline-specific theories as part of a “scholarly body of knowledge” (Wylie, 1994, p.2) – or at least a “unique” knowledge base (Parkinson, 2001) – has been suggested as one of the defining characteristics of a true profession. In the case of public relations, this is a development that has occurred relatively recently. Since public relations first began to emerge as a distinct practice in the early part of the 20th century, there has been a tendency to appropriate theories from other areas (such as organisational and media studies) to create a relevant theory base to explore, describe and predict public relations activities. However, these theories were often rarely more than a ‘best fit’ solution, and resulting areas of discrepancy led to much confusion surrounding the form and function of public relations. It could be argued therefore that the development of dedicated public relations theory – ideas that encompass the creation, maintenance and enhancement of relationships between organisations and publics as primary motivations – only began in the latter half of the 20th century with the work of people such as Grunig and Hunt, and latterly Ledingham and Bruning among others.

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This article takes a critical discourse approach to one aspect of the Australian WorkChoices industrial relations legislation: the government’s major advertisement published in national newspapers in late 2005 and released simultaneously as a 16-page booklet. This strategic move was the initial stage of one of the largest ‘information’ campaigns ever mounted by an Australian government, costing more than $AUD137 million. This article analyse the semiotic (visual and graphic) elements of the advertisement to uncover what these elements contribute to the message, particularly through their construction of both an image of the legislation and a portrayal of the Australian worker. We argue for the need to fuse approaches from critical discourse studies and social semiotics to deepen understanding of industrial relations phenomena such as the ‘hard sell’ to win the hearts and minds of citizens regarding unpopular new legislation.

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Benefit finding is a meaning making construct that has been shown to be related to adjustment in people with MS and their carers. This study investigated the dimensions, stability and potency of benefit finding in predicting adjustment over a 12 month interval using a newly developed Benefit Finding in Multiple Sclerosis Scale (BFiMSS). Usable data from 388 persons with MS and 232 carers was obtained from questionnaires completed at Time 1 and 12 months later (Time 2). Factor analysis of the BFiMSS revealed seven psychometrically sound factors: Compassion/Empathy, Spiritual Growth, Mindfulness, Family Relations Growth, Life Style Gains, Personal Growth, New Opportunities. BFiMSS total and factors showed satisfactory internal and retest reliability coefficients, and convergent, criterion and external validity. Results of regression analyses indicated that the Time 1 BFiMSS factors accounted for significant amounts of variance in each of the Time 2 adjustment outcomes (positive states of mind, positive affect, anxiety, depression) after controlling for Time 1 adjustment, and relevant demographic and illness variables. Findings delineate the dimensional structure of benefit finding in MS, the differential links between benefit finding dimensions and adjustment and the temporal unfolding of benefit finding in chronic illness.

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Indigenous Legal Relations in Australia is a welcome and refreshing addition to the current literature on Indigenous legal issues. Written by a team of highly qualified Indigenous and non-Indigenous academics who share a long term commitment to Indigenous legal and social justice issues, this book provides a clearly written and accessible introductory text for tertiary students and general readers alike who are seeking to gain a deeper understanding of the relationship between Indigenous Australians and the Anglo-Australian legal system.