1,721,006 research outputs found
Sampling size required for determining soil carbon and nitrogen properties at early establishment of second rotation hoop pine plantations in subtropical Australia
No full textInvestigations into forest soils face the problem of the high level of spatial variability that is an inherent property of all forest soils. In order to investigate the effect of changes in residue management practices on soil properties in hoop pine (Araucaria cunninghamii Aiton ex A. Cunn.) plantations of subtropical Australia it was important to understand the intensity of sampling effort required to overcome the spatial variability induced by those changes. Harvest residues were formed into windrows to prevent nitrogen (N) losses through volatilisation and erosion that had previously occurred as a result of pile and burn operations. We selected second rotation (2R) hoop pine sites where the windrows (10{15 m apart) had been formed 1, 2 and 3 years prior to sampling in order to examine the spatial variability in soil carbon (C) and N and in potential mineralisable N (PMN) in the areas beneath and between (inter-) the windrows. We examined the implications of soil variability on the number of samples required to detect differences in means for specific soil properties, at different ages and at specified levels of accuracy. Sample size needed to accurately reflect differences between means was not affected by the position where the samples were taken relative to the windrows but differed according to the parameter to be sampled. The relative soil sampling size required for detecting differences between means of a soil property in the inter-windrow and beneath-windrow positions was highly dependent on the soil property assessed and the acceptable relative sampling error. An alternative strategy for soil sampling should be considered, if the estimated sample size exceeds 50 replications. The possible solution to this problem is collection of composite soil samples allowing a substantial reduction in the number of samples required for chemical analysis without loss in the precision of the mean estimates for a particular soil property.No Full Tex
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Edaphic and Ecophysiological Responses to Early Establishment Weed Control and Fertilisation in F1 Hybrid Pine Plantations of Southeast Queensland
No full textPost-planting silviculture in the exotic pine plantations of Southeast Queensland focuses on fertilisation and weed control at early plantation establishment. Early establishment silviculture in pine plantations aims to reduce the competition for light, nutrients and water in the short term, while maximising resource conversion for growth in the long term. However, silviculture can be applied in a systematic way without necessarily considering the limitations to maximum tree growth at each site. Accordingly, silvicultural treatments could be applied in a site specific manner to better reflect the limitations to tree growth at each site (e.g. nutrition and/or water), or for maximum effectiveness based on seasonal limitations (e.g. weed competition, water availability). This research aimed to investigate the effects of early establishment weed control and fertilisation practices on soil carbon (C) and nitrogen (N) cycling (as an indicator of soil fertility), tree nutrition (particularly N nutrition), growth and eco-physiological responses, in the F1 hybrid exotic pine plantations (Pinus elliottii Engelm var. elliottii x Pinus caribaea Morelet var. hondurensis (Sènècl.) W.H.G. Barett & Golfari.) in the subtropics of Southeast Queensland.Thesis (PhD Doctorate)Doctor of Philosophy (PhD)Griffith School of EnvironmentScience, Environment, Engineering and TechnologyFull Tex
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Effect of Overlying Windrowed Harvest Residues on Soil Carbon and Nitrogen in Hoop Pine Plantations of Subtropical Australia
No full textBackground, Aims and Scope. Harvest residues were formed into windrows to prevent nitrogen (N) losses through volatilisation and erosion that occurred following pile and burn operations in hoop pine (Araucaria cunninghamii Aiton ex A. Cunn.) plantations of subtropical Australia. We selected second rotation (2R) hoop pine sites where the windrows (10-15 m apart) had been formed 1, 2 and 3 years prior to sampling in order to examine soil carbon (C) and N in the areas beneath and between the windrows. Methods. We used conventional chemical methods, anaerobic incubation assay, 13C and 15N natural abundance analyses and, solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. Results. Percent mineralisable N (PCMN) was the only parameter in the underneath windrow position at the Year 1 site that did not show a significant difference to the rest of the positions along the transect. However, positions adjacent to windrows did have significantly greater PCMN at the Year 1 site than other positions along the transect. PCMN, total N and total C were significantly greater underneath the windrows at the Year 3 site, whilst d13C was significantly more negative in the underneath windrow positions. Discussion. PCMN was the most sensitive biological indicator of the changes occurring in the soil due to decomposition of the windrows, with the beneath-windrow position having a significantly higher PCMN than the inter-windrow position (p<0.001) at the Year 3 site. Isotopic natural abundance for both 13C and 15N was able to detect the influx of labile materials from new residues. Solid-state 13C NMR was able to detect inputs of labile C from the windrows at the Year 1 site, whilst the increase in aromatic C at the Year 3 site was indicative of the more advanced stages of windrow decomposition. Conclusions. Decomposition of windrowed residues had a beneficial effect on soil N and C pools. However, the effect remained localised after 3 years, indicating that trees needed to be planted close to the windrows to gain any benefit from residue decomposition. Recommendations and Perspectives. The use of windrows allows a clear planting area and provides a good barrier against soil erosion. However, trees can only gain access to the nutrients from the decomposing residues if they are planted close to the windrows. Limiting the width of the cleared areas to allow for only 2 planting rows will give the maximum benefit to the developing trees.No Full Tex
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