136 resultados para Bruggeman, Carol


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Services are very important to the UK balance of trade; a surplus has been recorded for trade in services every year since 1966. Construction professional services exports (CPS), which cover architecture, engineering and surveying (AES), have also increased, contributing over £3bn to the UK trade balance in 2007. The changing environment of construction professional services exports complicates the validity of the characteristics and definitions of services as described in the research literature and official export statistics. Through semi-structured interviews undertaken with large consulting engineers and a round-table discussion with industry and government representatives, the research found that the impact of globalisation and the changes in the construction business environment, such as increasing foreign ownership and changing forms of procurement, are not fully reflected in the official statistics. There have also been rapid changes in technology, procurement and methods of delivery which have impacted exporting AES firms and a more appropriate set of characteristics is needed to better reflect the project-specific and knowledge-intensive nature of AES firms.

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Globalisation has prompted increasing numbers of construction profes-sional services (CPS) firms to internationalise and export their services. The driver has been twofold; firstly to increase turnover/profits and sec-ondly, to minimise the risk of a reliance on working in a single domestic market which has a fluctuating demand. Secondly, where firms have out-grown their domestic market, and in order to expand, they must export overseas. There has been little research into the way CPS firms operate overseas, yet construction represents approximately 10% of global GDP; this means that understanding CPS firms is important. This paper investigates how CPS firms internationalise and the drivers that impact their decisions and operations overseas. A survey was undertaken and interviews conducted that showed CPS firms are project driven, in-vesting heavily in the process of seeking work/bidding for projects, and are very focused on delivering projects with minimum risk. Increasing foreign ownership, changing procurement approaches and more consolidation of CPS firms in the global marketplace present a changing business land-scape. The research develops a framework of tangible and intangible factors, such as competencies, business organisation culture, leadership and reputation in order to better understand how CPS firms export their ser-vices. Whilst all CPS firms share the same framework of factors, the re-sulting synergies are different not only for each firm but also for each pro-ject. The knowledge-intensive and project-based nature of CPS firms presents a challenge in understanding the way they operate in the global service economy.

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Petal development and senescence entails a normally irreversible process. It starts with petal expansion and pigment production, and ends with nutrient remobilization and ultimately cell death. In many species this is accompanied by petal abscission. Post-harvest stress is an important factor in limiting petal longevity in cut flowers and accelerates some of the processes of senescence such as petal wilting and abscission. However, some of the effects of moderate stress in young flowers are reversible with appropriate treatments. Transcriptomic studies have shown that distinct gene sets are expressed during petal development and senescence. Despite this, the overlap in gene expression between developmental and stress-induced senescence in petals has not been fully investigated in any species. Here a custom-made cDNA microarray from Alstroemeria petals was used to investigate the overlap in gene expression between developmental changes (bud to first sign of senescence) and typical post-harvest stress treatments. Young flowers were stressed by cold or ambient temperatures without water followed by a recovery and rehydration period. Stressed flowers were still at the bud stage after stress treatments. Microarray analysis showed that ambient dehydration stress accelerates many of the changes in gene expression patterns that would normally occur during developmental senescence. However, a higher proportion of gene expression changes in response to cold stress were specific to this stimulus and not senescence related. The expression of 21 transcription factors was characterized, showing that overlapping sets of regulatory genes are activated during developmental senescence and by different stresses.

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It is proposed that post-harvest longevity and appearance of salad crops is closely linked to pre-harvest leaf morphology (cell and leaf size) and biophysical structure (leaf strength). Transgenic lettuce plants (Lactuca sativa cv. Valeria) were produced in which the production of the cell wall-modifying enzyme xyloglucan endotransglucosylase/hydrolase (XTH) was down-regulated by antisense inhibition. Independently transformed lines were shown to have multiple members of the LsXTH gene family down-regulated in mature leaves of 6-week-old plants and during the course of shelf life. Consequently, xyloglucan endotransglucosylase (XET) enzyme activity and action were down-regulated in the cell walls of these leaves and it was established that leaf area and fresh weight were decreased while leaf strength was increased in the transgenic lines. Membrane permeability was reduced towards the end of shelf life in the transgenic lines relative to the controls and bacteria were evident inside the leaves of control plants only. Most importantly, an extended shelf-life of transgenic lines was observed relative to the non-transgenic control plants. These data illustrate the potential for engineering cell wall traits for improving quality and longevity of salad crops using either genetic modification directly, or by using markers associated with XTH genes to inform a commercial breeding programme.

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We have been using Virus-Induced Gene Silencing (VIGS) to test the function of genes that are candidates for involvement in floral senescence. Although VIGS is a powerful tool for assaying the effects of gene silencing in plants, relatively few taxa have been studied using this approach, and most that have are in the Solanaceae. We typically use silencing of phytoene desaturase (PDS) in preliminary tests of the feasibility of using VIGS. Silencing this gene, whose product is involved in carotene biosynthesis, results in a characteristic photobleaching phenotype in the leaves. We have found that efficient silencing requires the use of fragments that are more than 90% homologous to the target gene. To simplify testing the effectiveness of VIGS in a range of species, we designed a set of universal primers to a region of the PDS gene that is highly conserved among species, and that therefore allows an investigator to isolate a fragment of the homologous PDS gene from the species of interest. We report the sequences of these primers and the results of VIGS experiments in horticultural species from the Asteraceae, Leguminosae, Balsaminaceae and Solanaceae.

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This paper introduces a method for simulating multivariate samples that have exact means, covariances, skewness and kurtosis. We introduce a new class of rectangular orthogonal matrix which is fundamental to the methodology and we call these matrices L matrices. They may be deterministic, parametric or data specific in nature. The target moments determine the L matrix then infinitely many random samples with the same exact moments may be generated by multiplying the L matrix by arbitrary random orthogonal matrices. This methodology is thus termed “ROM simulation”. Considering certain elementary types of random orthogonal matrices we demonstrate that they generate samples with different characteristics. ROM simulation has applications to many problems that are resolved using standard Monte Carlo methods. But no parametric assumptions are required (unless parametric L matrices are used) so there is no sampling error caused by the discrete approximation of a continuous distribution, which is a major source of error in standard Monte Carlo simulations. For illustration, we apply ROM simulation to determine the value-at-risk of a stock portfolio.

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We derive general analytic approximations for pricing European basket and rainbow options on N assets. The key idea is to express the option’s price as a sum of prices of various compound exchange options, each with different pairs of subordinate multi- or single-asset options. The underlying asset prices are assumed to follow lognormal processes, although our results can be extended to certain other price processes for the underlying. For some multi-asset options a strong condition holds, whereby each compound exchange option is equivalent to a standard single-asset option under a modified measure, and in such cases an almost exact analytic price exists. More generally, approximate analytic prices for multi-asset options are derived using a weak lognormality condition, where the approximation stems from making constant volatility assumptions on the price processes that drive the prices of the subordinate basket options. The analytic formulae for multi-asset option prices, and their Greeks, are defined in a recursive framework. For instance, the option delta is defined in terms of the delta relative to subordinate multi-asset options, and the deltas of these subordinate options with respect to the underlying assets. Simulations test the accuracy of our approximations, given some assumed values for the asset volatilities and correlations. Finally, a calibration algorithm is proposed and illustrated.

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