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| 2. |
- Fransson, Ann-Mari
(författare)
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Can silver and other heavy metal concentrations in leaves be used in order to identify tree root intrusion into sewage systems and storm-water drains?
- 2019
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Ingår i: Arboricultural Journal, The International Journal of Urban Forestry. - : Taylor & Francis. - 0307-1375 .- 2168-1074. ; 41:4, s. 212-225
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Tidskriftsartikel (refereegranskat)abstract
- There is a growing awareness of the value of trees for climate adaptation, human health, and biodiversity in urban spaces, and methods for identifying and calculating the benefits of trees have been developed. However, tree roots frequently intrude into sewer pipes and storm-water drains, causing costly damage. Identifying the individual trees that cause damage would be helpful but has proved difficult. There is a need for non-destructive identification of root intruding trees, in order to evaluate the cost and benefits of individual trees. The concentrations of eight heavy metals (silver, gold, cadmium, lead, palladium, rubidium, antimony, and zinc) and of potassium were evaluated in 19 pairs of trees/shrubs in Malmö, southern Sweden. It was found that the concentrations of silver were approximately 28% higher in leaves from trees whose roots had entered sewers than in control trees. Trees whose roots intruded storm-water drains had slightly higher leaf potassium levels, while the concentrations of other elements did not differ from those in control trees. Thus, it may be possible to use the silver concentration in tree leaves to identify individuals with roots intruding into sewer systems. However, considerable differences were found between species, so further tests are required before the method can be adopted in practice.
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| 5. |
- Packham, J. R., et al.
(författare)
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Swedish beech forests and the storm gap theory.
- 2012
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Ingår i: Arboricultural Journal, The International Journal of Urban Forestry. - 0307-1375 .- 2168-1074. ; 34:3, s. 151-159
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Tidskriftsartikel (refereegranskat)
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| 7. |
- Sjöman, Henrik
(författare)
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Magnolias as urban trees - a preliminary evaluation of drought tolerance in seven magnolia species
- 2018
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Ingår i: Arboricultural Journal. - : Informa UK Limited. - 0307-1375 .- 2168-1074. ; 40, s. 47-56
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Tidskriftsartikel (refereegranskat)abstract
- Tree selection must ensure that trees are capable of thriving in the environment in which they are placed. Inappropriate species or trees of poor quality will never develop any substantial capacity for delivering ecosystem services. The aim of this study is to evaluate seven species of Magnolia for their drought tolerance by estimating their water potential at leaf turgor loss to help provide quantitative data for their capacity to tolerate dry urban sites. According to the results, Magnolia virginiana is ranked as the most drought-tolerant, while Magnolia x loebneri Leonard Messel is the most sensitive to drought. However, in comparison with other plant groups previously studied, magnolias have to be treated as drought sensitive. Consequently, magnolias used in this study should be used in garden and park environments, as their potential for use along streets can be limited by their vulnerability to drought. The turgor loss point methodology used in the study provides an efficient alternative to decades of observation, especially when new genotypes or underutilised trees are being evaluated. It is now possible to show the group's general sensitivity to drought as well as quantifying individual species sensitivity to drought.
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| 8. |
- Benninga, Simon, et al.
(författare)
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On the Use of Numeraires in Option Pricing
- 2002
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Ingår i: The Journal of derivatives. - : Pageant Media. - 2168-8524 .- 1074-1240. ; 10:2, s. 43-58
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Tidskriftsartikel (refereegranskat)abstract
- Significant computational simplification is achieved when option pricing is approached through the change of numeraire technique. By pricing an asset in terms of another traded asset (the numeraire), this technique reduces the number of sources of risk that need to be accounted for. The technique is useful in pricing complicated derivatives. This article discusses the underlying theory of the numeraire technique, and illustrates it with five pricing problems: pricing savings plans that offer a choice of interest rates; pricing convertible bonds; pricing employee stock ownership plans; pricing options whose strike price is in a currency different from the stock price; and pricing options whose strike price is correlated with the short-term interest rate. [PUBLICATION ABSTRACT]
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| 9. |
- Larsson, Karl, 1974-
(författare)
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Pricing Commodity Swaptions in Multifactor Models
- 2011
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Ingår i: Journal of Derivatives. - : Institutional Investor. - 1074-1240 .- 2168-8524. ; 19:2, s. 32-44
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Tidskriftsartikel (refereegranskat)abstract
- The menu of swaps available in the market today ranges far beyond the basic fixed-for-floating interest rateswap. Commodity swaps specifying a series of future cash flows, whereby one counterparty pays a fixed dollar amount and the other pays the price appreciation on some underlying commodity, are a prime example. And if commodity swaps become popular, commodity swaptions will naturally be introduced. But valuing commodity swaptions involves modeling the behavior of both future interest rates and future commodity prices for all of the payment dates. The standard approach is Monte Carlo simulation, which is complicated and time consuming. Here, Larsson introduces an approximation that is quite mild in terms of the error it introduces and for which the execution time for a given level of accuracy is improved by several orders of magnitude.
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| 10. |
- Lindström, Erik
(författare)
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Fourier Method for Valuation of Options under Parameter and State Uncertainty
- 2019
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Ingår i: Journal of Derivatives. - : Pageant Media US. - 1074-1240 .- 2168-8524. ; 27:2, s. 62-80
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Tidskriftsartikel (refereegranskat)abstract
- Mainstream option valuation theory relies implicitly on the assumption that latent states (such as stochastic volatility) and parameters are perfectly known, an assumption that is dubious in many ways. Computing the value of options under the assumption of perfect knowledge will typically introduce bias. Correcting for the bias is straightforward but can be computationally expensive. Fourier-based methods for computing option values are nowadays the preferred computational technique in the financial industry as a result of speed and accuracy. The author shows that the bias correction for parameter and state uncertainty for a large class of processes can be incorporated into the Fourier framework, resulting in substantial computational savings compared with Monte Carlo methods or deterministic quadrature rules previously used. In addition, the author proposes extensions, such as time varying parameters and hyperparameters, to the class of uncertainty models. The author finds that the proposed Fourier method is retaining all the good properties that are associated with Fourier methods; it is fast, accurate, and applicable to a wide range of models. Furthermore, the empirical performance of the corrected models is almost uniformly better than that of their noncorrected counterparts when evaluated on S&P 500 option data.
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