3,158 research outputs found

    A comparison of UK equity and property duration

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    This paper considers the duration of property and equity. A general formula for duration of asset classes is derived. It is shown that calculations which assume, usually implicitly, that the flow-through of inflation to cash flow is zero, produce misleadingly high durations for property and equities. These are typically in the range 15 to 25 years. Simulations using the formulae show that property has some bond-like characteristics. The results indicate that, for realistic flow-through rates, equities have a higher duration than property. The flow-through rate is the most important variable in the estimation of equities. Using historical data, equity duration is estimated at 8.65 years and property’s at 3.15 years. These are substantially lower than those commonly cited. If these values can be substantiated, and if higher values are used in practice, portfolio immunisation strategies may need to be reconsidered

    Covariate linkage analysis of GAW14 simulated data incorporating subclinical phenotype, sex, population, parent-of-origin, and interaction

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    BACKGROUND: We evaluate a method for the incorporation of covariates into linkage analysis using the Genetic Analysis Workshop 14 simulated data. Focusing on a randomly chosen replicate (42) we investigated the effect of the 12 subclinical phenotypes, sex, population, and parent-of-origin on the linkage signal from a model-free linkage analysis of Kofendrerd Personality Disorder. RESULTS: We detected a linkage peak on chromosome 1, at about 175 cM, which varied depending upon individuals' status for subclinical phenotype b. A linkage peak on chromosome 3 (310 cM) was found not to depend upon subclinical phenotype status. Further peaks were found on chromosomes 5 (12 cM), 9 (4 cM), and 10 (95 cM), depending on the status of subclinical phenotypes a, k, and c/d/g, respectively. CONCLUSION: Retrospective comparison of our results with the simulation model showed correct identification of disease loci D1-5 on chromosomes 1, 3, 5, 9 and 10, respectively

    Species interactions regulate the collapse of biodiversity and ecosystem function in tropical forest fragments

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    Competitive interactions among species with similar ecological niches are known to regulate the assembly of biological communities. However, it is not clear whether such forms of competition can predict the collapse of communities and associated shifts in ecosystem function in the face of environmental change. Here, we use phylogenetic and functional trait data to test whether communities of two ecologically important guilds of tropical birds (frugivores and insectivores) are structured by species interactions in a fragmented Amazonian forest landscape. In both guilds, we found that forest patch size, quality, and degree of isolation influence the phylogenetic and functional trait structure of communities, with small, degraded, or isolated forest patches having an increased signature of competition (i.e., phylogenetic and functional trait overdispersion in relation to null models). These results suggest that local extinctions in the context of fragmentation are nonrandom, with a consistent bias toward more densely occupied regions of niche space. We conclude that the loss of biodiversity in fragmented landscapes is mediated by niche-based competitive interactions among species, with potentially far-reaching implications for key ecosystem processes, including seed dispersal and plant damage by phytophagous insects

    Evaluation of ultrasound technology to break seed dormancy of common lambsquarters (Chenopodium album)

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    Although seed dormancy is advantageous for annual plants in the wild, unsynchronized germination in the laboratory leads to increased error in measurements. Therefore techniques to promote and synchronize germination are routinely used. Ultrasound is one of the newest methods for breaking dormancy in weed seeds. We have investigated whether ultrasonic waves can be used to break seed dormancy of common lambsquarters (Chenopodium album), a highly competitive annual weed that leads to significant reduction of yields of corn, soybeans, and sugar beets. Ultrasonic waves with frequency of 35kH were applied for 0 (control), 5, 10, 15 and 30 minutes using a completely randomized design. The results showed that the use of ultrasound waves generally enhanced the traits under investigation in the treated samples compared to the control sample. The maximum enhancement of germination percentage (180%), seedling dry weight (78%), and seedling vigor index I (271%) and II (392%) was seen in the common lambsquarters samples treated with ultrasound for 15 minutes and seedling length (40%) at 30 minutes compared to the control samples. Radical lengths were not statistically different from controls under any treatment and plumule length only increased marginally. These changes are reflected in seedling vigor index I and II measurements. For some of these traits, increasing the length of ultrasound treatment to 30 minutes had negative effects. These results demonstrate that ultrasound technology can be used as a quick, and efficient non-destructive method to break seed dormancy in common lambsquarters

    Excitations in the Halo Nucleus He-6 Following The Li-7(gamma,p)He-6 Reaction

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    A broad excited state was observed in 6-He with energy E_x = 5 +/- 1 MeV and width Gamma = 3 +/- 1 MeV, following the reaction Li-7(gamma,p)He-6. The state is consistent with a number of broad resonances predicted by recent cluster model calculations. The well-established reaction mechanism, combined with a simple and transparent analysis procedure confers considerable validity to this observation.Comment: 3 pages of LaTeX, 3 figures in PostScript, approved for publication in Phys. Rev. C, August, 200

    On the Hausdorff and packing measures of typical compact metric spaces

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    We study the Hausdorff and packing measures of typical compact metric spaces belonging to the Gromov–Hausdorff space (of all compact metric spaces) equipped with the Gromov–Hausdorff metric.Publisher PDFPeer reviewe

    Tailored second line therapy in asthmatic children with the arginine-16 genotype

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    The arginine-16 beta-2 receptor genotype confers increased susceptibility to exacerbations in asthmatic children taking regular long acting beta-2 agonists. We therefore evaluated using montelukast as an alternative to salmeterol as tailored second line asthma controller therapy in children expressing this susceptible genotype. 62 persistent asthmatic children with the homozygous arginine-16 genotype were randomized to receive salmeterol 50ug bid or montelukast 5/10mg od as add on to inhaled fluticasone for 1 year. School absences (the primary outcome) were reduced with montelukast arm compared to salmeterol: difference in score = 0.40 (95%CI 0.07-0.87) p=0.005. Albuterol use was also reduced with montelukast compared with salmeterol: difference in score = 0.47 (95%CI 0.16-0.79) p<0.0001. Greater improvements occurred in both symptom and quality of life scores with montelukast vs salmeterol, while there was no difference in FEV1. Montelukast may be suitable as tailored second line controller therapy instead of salmeterol in asthmatic children expressing the susceptible arginine-16 genotype - moving towards a personalised medicine approach to management
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