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Search Results: 1 - 10 of 1407 matches for " Eastaugh CS "
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Comment on Chiesi et al. (2011): “Use of BIOME-BGC to simulate Mediterranean forest carbon stocks”
Eastaugh CS
iForest : Biogeosciences and Forestry , 2011, DOI: 10.3832/ifor0593-004
Abstract: The mechanistic forest growth model BIOME-BGC utilizes a “spin-up” procedure to estimate site parameters for forests in a steady-state condition, as they may have been expected to be prior to anthropogenic influence. Forests in this condition have no net growth, as living biomass accumulation is balanced by mortality. To simulate current ecosystems it is necessary to reset the model to reflect a forest of the correct development stage. The alternative approach of simply post-adjusting the estimates of net primary production is fundamentally flawed, and should not be pursued.
Incorporating management history into forest growth modelling
Eastaugh CS,Hasenauer H
iForest : Biogeosciences and Forestry , 2011, DOI: 10.3832/ifor0597-004
Abstract: Mechanistic modelling is an important tool for understanding the impacts of climate change and pollutants on forest growth. One of the common practical limitations of these models is a lack of specific information regarding management activities such as thinning or harvesting, which can have a very strong influence on the accuracy of results. The use of inventory data for model parameterization and calibration is also problematic, as inventories are designed to have large volumes of data amalgamated to give accurate mean results across large areas. The precision of single point estimates is often quite low.This study uses BIOME-BGC to model forest growth on 1133 sites of the Austrian National Forest Inventory, and develops a method to estimate timber removal patterns prior to the commencement of record keeping on the sites. Recognizing the poor precision of individual point estimates in the data, we do not seek to precisely calibrate the model to the data on each point. Rather, we assume that the point-wise inventory estimates will be normally distributed around the true values. We then model each site assuming no management interventions, and compare this with inventory results. Plotting the “error” between model results and NFI data shows a strong right-skew, reflecting the modelled lack of timber removals. A Box-Cox transformation of the error plot, centred on zero, would represent an unbiased model estimate of the data, thus we can determine the historic timber removals as the difference between the original error curve and its Box-Cox transformation. Calibrating the model with this information allow us to represent forest volume with greater accuracy than would otherwise be possible.
Impacts of climate change on the establishment, distribution, growth and mortality of Swiss stone pine (Pinus cembra L.)
Boden S,Pyttel P,Eastaugh CS
iForest : Biogeosciences and Forestry , 2010, DOI: 10.3832/ifor0537-003
Abstract: Anticipated future climate changes are expected to significantly influence forest ecosystems, particularly in treeline ecotones. Climate change will have both direct and indirect effects on the future distribution of alpine tree species, some of which will be positive and others negative. Although increased temperatures are on the whole likely to have a positive impact on growth and distribution of Swiss stone pine (Pinus cembra L.), indirect effects that influence seed dispersal may threaten the population viability of species. The complexity of the interrelations between climatic and non-climatic factors demands further research, which should include long-term monitoring.
Assessing Forest Production Using Terrestrial Monitoring Data
Hubert Hasenauer,Chris S. Eastaugh
International Journal of Forestry Research , 2012, DOI: 10.1155/2012/961576
Abstract: Accurate assessments of forest biomass are becoming an increasingly important aspect of natural resource management. Besides their use in sustainable resource usage decisions, a growing focus on the carbon sequestration potential of forests means that assessment issues are becoming important beyond the forest sector. Broad scale inventories provide much-needed information, but interpretation of growth from successive measurements is not trivial. Even using the same data, various interpretation methods are available. The mission of this paper is to compare the results of fixed-plot inventory designs and angle-count inventories with different interpretation methods. The inventory estimators that we compare are in common use in National Forest Inventories. No method should be described as “right” or “wrong”, but users of large-scale inventory data should be aware of the possible errors and biases that may be either compensated for or magnified by their choice of interpretation method. Wherever possible, several interpretation methods should be applied to the same dataset to assess the possibility of error. 1. Introduction National forest inventories are an expensive and time-consuming operation, particularly in large, remote, and inhospitable regions. There is therefore great interest in alternative measures to estimate forest growth, such as remote sensing [1] or mechanistic process modeling [2]. These methods, however, are not a direct measurement of the same physical characteristics as in an inventory, and it is reasonable to suggest that estimates made with these alternatives should be shown to be unbiased with reference to ground data. In the near future, national forest inventories will form an integral part of the way that many nations determine their national carbon balance, and inventories are used to estimate forest increment as a means of monitoring their value as a carbon sink. Relatively minor errors in current standing volume estimates may have little practical or policy impact, but these may translate to substantial errors and biases in the estimate of forest increment. In some cases, these biases may mean the difference between forest areas being assessed as a sink or a source of CO2 or could result in erroneous (but substantial) financial penalties to countries signing up to successor agreements to the Kyoto protocol. Conversely, countries may claim carbon credits for a degree of forest sequestration that does not in fact exist. Until recently, inventories were conducted solely as a means of measuring the timber resource present in a
A cautionary note regarding comparisons of fire danger indices
C. S. Eastaugh,A. Arpaci,H. Vacik
Natural Hazards and Earth System Sciences (NHESS) & Discussions (NHESSD) , 2012, DOI: 10.5194/nhess-12-927-2012
Abstract: Over the past decade, several methods have been used to compare the performance of fire danger indices in an effort to find the most appropriate indices for particular regions or circumstances. Various authors have proposed comparators and demonstrated different responses of indices to their tests, but rarely has much effort been put into demonstrating the validity of the comparators themselves. We present a demonstration that many of the published comparators are sensitive to the different frequency distributions, that may be inherent in the performance of the different indices, and outline a non-parametric method that may be useful for future work. We compare four hypothetical fire danger indices, three of which are simple mathematical transformations of each other. The hypothesis tested is that the comparators often used in such studies may indicate spurious performance differences between these indices, which is found to be the case. Non-parametric methods are robust to differences in index value frequency distribution and may allow more valid comparisons of fire danger indices. The new comparison method is shown to have advantages over other non-parametric comparators.
A Systematic Examination of Colour Development in Synthetic Ultramarine According to Historical Methods
Ian Hamerton, Lauren Tedaldi, Nicholas Eastaugh
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0050364
Abstract: A number of historical texts are investigated to ascertain the optimum conditions for the preparation of synthetic ultramarine, using preparative methods that would have been available to alchemists and colour chemists of the nineteenth century. The effect of varying the proportion of sulphur in the starting material on the colour of the final product is investigated. The optimum preparation involves heating a homogenised, pelletised mixture of kaolin (100 parts), sodium carbonate (100 parts), bitumen emulsion (or any ‘sticky’ carbon source) (12 parts) and sulphur (60 parts) at 750°C for ca. 4 hours. At this stage the ingress of air should be limited. The sample is allowed to cool in the furnace to 500°C, the ingress of air is permitted and additional sulphur (30 parts) is introduced before a second calcination step is undertaken at 500°C for two hours. The products obtained from the optimum synthesis have CIE ranges of x = 0.2945-0.3125, y = 0.2219–0.2617, Y = 0.4257?0.4836, L* = 3.8455–4.3682, a* = 4.2763–7.6943, b* = ?7.6772–(?)3.3033, L = 3.8455–4.3682, C = 5.3964–10.8693, h = 315.0636–322.2562. The values are calculated using UV/visible near infrared spectra using Lazurite [1], under D65 illumination, and the 1931 2° observer.
Stephenson et al.'s ecological fallacy
C. S. Eastaugh,C. Thurnher,H. Hasenauer,J. K. Vanclay
Quantitative Biology , 2014,
Abstract: After more than a century of research the typical growth pattern of a tree was thought to be fairly well understood. Following germination height growth accelerates for some time, then increment peaks and the added height each year becomes less and less. The cross sectional area (basal area) of the tree follows a similar pattern, but the maximum basal area increment occurs at some time after the maximum height increment. An increase in basal area in a tall tree will add more volume to the stem than the same increase in a short tree, so the increment in stem volume (or mass) peaks very late. Stephenson et al. challenge this paradigm, and suggest that mass increment increases continuously. Their analysis methods however are a textbook example of the ecological fallacy, and their conclusions therefore unsupported.
International Journal of Bioinformatics Research , 2011,
Abstract: One of the major tasks carried by biologist today is to understand the nature of proteins. How this largeprotein molecule folds themselves into some form and carryout the prescribed biochemical reactions.Hydrophobic interaction is the dominant force towards this task. To understand this interaction, a simple statisticalanalysis on the contribution of hydrophobic residues was carried out. Large Hydrophobic Residues (LHR) such asPhenylalanine (F), Isoleucine (I), Leucine (L), Methionine (M) and Valine (V) – (FILMV) as well as smallhydrophobic residues (SHR) Glycine (G), Alanine (A), Proline (P), Cysteine (C) and Tryptophan (W) - (GAPCW)were studied in all proteins of given organisms. The organisms include Homo sapiens, Macaca Mullatta, Pantroglodytes, Canis familiaris, Gallus gallus, Mus musculus, Rattus norvegicus, Bos taurus, Drosophilamelonogaster, Monodelphis domestica, Danio rerio, Stronglycentrolus purpuratus, Anopheles gambiae, Apismellifera, Arabidopsis thaliana, Tribolium castaneum, Saccharomyces cerevisae, Schizosaccharomyces pombeand Caenorhabditis elegans. It is observed that the protein prefers to have 27% large hydrophobic residues tomaintain the required hydrophobicity. In animal, particularly in human, it is observed less. It is interesting to notethat small hydrophobic residues balance this lack in number by a factor of 1:3. So is the reason why the length ofthe animal proteins increases. This new finding on the contribution of hydrophobic residues in protein stability willbe discussed in detail
Editorial Circumcision: Controversies and Prospects
CS Lukong
Journal of Surgical Technique and Case Report , 2011,
Abstract: Click on the link to view the editorial. Journal of Surgical Technique and Case Report | Jul-Dec 2011 | Vol-3 | Issue-2
Evaluating the rural health placements of the Rural Support Network at the Faculty of Health Sciences, University of Cape Town
CS Naidu
South African Family Practice , 2012,
Abstract: Objectives: The Rural Support Network (RSN) is an undergraduate student society that aims to raise awareness among the student body of the plight of rural health in South Africa, and organises individual and group placements in rural hospitals during vacations. This research aimed to evaluate these placements from the students’ perspectives. Design: In-depth, face-to-face interviews were conducted with 10 students and nine placement-reflective reports were reviewed. The data were analysed and coded for key themes using a constant, comparative grounded theory approach. Setting: Faculty of Health Sciences (FHS) at the University of Cape Town. Subjects: Students who had been on RSN placements in 2010. Results: Students reported that the experience exceeded their expectations of learning new skills and observing and performing procedures. They gained significant insights into rural health care and were inspired to contribute to rural health in future. Their experiences helped them to gain confidence and an appreciation of the psycho-social aspects of patient care. The importance of community empowerment and of connecting and building relationships with communities was also emphasised. Challenges pertained to conflict within groups, incidents of unprofessional health care and being unable to help as much as they would have liked. Conclusion: The study highlights the impact that positive experiences of rural health may have on health science students’ interest in, passion for, and commitment to practising in underserved rural areas. Students’ key recommendations for the FHS included the development of a rural programme within the undergraduate curriculum. Better group composition and improved planning and co-ordination of placements by the RSN were also recommended.
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