Advantage of single-trial models for response to selection in wheat breeding multi-environment trials

An investigation was conducted to evaluate the impact of experimental designs and spatial analyses (single-trial models) of the response to selection for grain yield in the northern grains region of Australia (Queensland and northern New South Wales). Two sets of multi-environment experiments were considered. One set, based on 33 trials conducted from 1994 to 1996, was used to represent the testing system of the wheat breeding program and is referred to as the multi-environment trial (MET). The second set, based on 47 trials conducted from 1986 to 1993, sampled a more diverse set of years and management regimes and was used to represent the target population of environments (TPE). There were 18 genotypes in common between the MET and TPE sets of trials. From indirect selection theory, the phenotypic correlation coefficient between the MET and TPE single-trial adjusted genotype means [r(p(MT))] was used to determine the effect of the single-trial model on the expected indirect response to selection for grain yield in the TPE based on selection in the MET. Five single-trial models were considered: randomised complete block (RCB), incomplete block (IB), spatial analysis (SS), spatial analysis with a measurement error (SSM) and a combination of spatial analysis and experimental design information to identify the preferred (PF) model. Bootstrap-resampling methodology was used to construct multiple MET data sets, ranging in size from 2 to 20 environments per MET sample. The size and environmental composition of the MET and the single-trial model influenced the r(p(MT)). On average, the PF model resulted in a higher r(p(MT)) than the IB, SS and SSM models, which were in turn superior to the RCB model for MET sizes based on fewer than ten environments. For METs based on ten or more environments, the r(p(MT)) was similar for all single-trial models.

A microarray study of post-mortem mRNA degradation in mouse brain tissue

Background: Although there is evidence that post-mortem interval (PMI) is not a major contributor to reduced overall RNA integrity, it may differentially affect a subgroup of gene transcripts that are susceptible to PMI-related degradation. This would particularly have ramifications for microarray studies that include a broad spectrum of genes. Method: Brain tissue was removed from adult mice at 0, 6, 12, 18, 24,36 and 48 h post-mortem. RNA transcript abundance was measured by hybridising RNA from the zero time point with test RNA from each PMI time point, and differential gene expression was assessed using cDNA microarrays. Sequence and ontological analyses were performed on the group of RNA transcripts showing greater than two-fold reduction. Results: Increasing PMI was associated with decreased tissue pH and increased RNA degradation as indexed by 28S/18S ribosomal RNA ratio. Approximately 12% of mRNAs detected on the arrays displayed more than a two-fold decrease in abundance by 48 It post-mortem. An analysis of nucleotide composition provided evidence that transcripts with the AUUUA motif in the 3' untranslated region (3'UTR) were more susceptible to PMI-related RNA degradation, compared to transcripts not carrying the 3'UTR AUUUA motif. Consistent with this finding, ontological analysis showed transcription factors and elements to be over-represented in the group of transcripts susceptible to degradation. Conclusion: A subgroup of mammalian mRNA transcripts are particularly susceptible to PMI-related degradation, and as a group, they are more likely to carry the YUTR AUUUA motif. PMI should be controlled for in human and animal model post-mortem brain studies, particularly those including a broad spectrum of mRNA transcripts. (c) 2005 Elsevier B.V. All rights reserved.

Variance components analyses of multiple asthma traits in a large sample of Australian families ascertained through a twin proband

Background: Intermediate phenotypes are often measured as a proxy for asthma. It is largely unclear to what extent the same set of environmental or genetic factors regulate these traits. Objective: Estimate the environmental and genetic correlations between self-reported and clinical asthma traits. Methods: A total of 3073 subjects from 802 families were ascertained through a twin proband. Traits measured included self-reported asthma, airway histamine responsiveness (AHR), skin prick response to common allergens including house dust mite (Dermatophagoides pteronyssinus [D. pter]), baseline lung function, total serum immunoglobulin E (IgE) and eosinophilia. Bivariate and multivariate analyses of eight traits were performed with adjustment for ascertainment and significant covariates. Results: Overall 2716 participants completed an asthma questionnaire and 2087 were clinically tested, including 1289 self-reported asthmatics (92% previously diagnosed by a doctor). Asthma, AHR, markers of allergic sensitization and eosinophilia had significant environmental correlations with each other (range: 0.23-0.89). Baseline forced expiratory volume in 1 s (FEV1) showed low environmental correlations with most traits. Fewer genetic correlations were significantly different from zero. Phenotypes with greatest genetic similarity were asthma and atopy (0.46), IgE and eosinophilia (0.44), AHR and D. pter (0.43) and AHR and airway obstruction (-0.43). Traits with greatest genetic dissimilarity were FEV1 and atopy (0.05), airway obstruction and IgE (0.07) and FEV1 and D. pter (0.11). Conclusion: These results suggest that the same set of environmental factors regulates the variation of many asthma traits. In addition, although most traits are regulated to great extent by specific genetic factors, there is still some degree of genetic overlap that could be exploited by multivariate linkage approaches.

Molecular systematics of the Philippine malaria vector Anopheles flavirostris

Allozyme and molecular sequence data from the malaria vector Anopheles flavirostris (Ludlow) (Diptera: Culicidae) were analysed from 34 sites throughout the Philippines, including the type locality, to test the hypothesis that this taxon is a single panmictic species. A finer-scaled allozyme study, of mainly Luzon samples, revealed no fixed genetic differences in sympatric sites and only low levels of variation. We obtained data from partial sequences for the internal transcribed spacer 2 (ITS2) (483 bp), the third domain (D3) (330 bp) of the 28S ribosomal DNA subunit and cytochrome c oxidase subunit I (COI) of mitochondrial DNA (261 bp). No sequence variation was observed for ITS2, only a one base pair difference was observed between Philippine and Indonesian D3 sequences and An. flavirostris sequences were unique, confirming their diagnostic value for this taxon. Sixteen COI haplotypes were identified, giving 25 parsimony informative sites. Neighbour-Joining, Maximum Parsimony, Maximum Likelihood and Bayesian phylogenetic analysis of COI sequences for An. flavirostris and outgroup taxa revealed strong branch support for the monophyly of An. flavirostris, thus confirming that Philippine populations of this taxon comprise a single separate species within the Minimus Subgroup of the Funestus Group. Variation in the behaviour of An. flavirostris is likely to be intraspecific rather than interspecific in origin. © 2006 The Royal Entomological Society.

Some results on the design of field experiments for comparing unreplicated treatments

In early generation variety trials, large numbers of new breeders' lines need to be compared, and usually there is little seed available for each new line. A so-called unreplicated trial has each new line on just one plot at a site, but includes several (often around five) replicated check or control (or standard) varieties. The total proportion of check plots is usually between 10% and 20%. The aim of the trial is to choose some good performing lines (usually around 1/3 of those tested) to go on for further testing, rather than precise estimation of their mean yield. Now that spatial analyses of data from field experiments are becoming more common, there is interest in an efficient layout of an experiment given a proposed spatial analysis. Some possible design criteria are discussed, and efficient layouts under spatial dependence are considered.

Efficient experimental designs when most treatments are unreplicated

In early generation variety trials, large numbers of new breeders' lines (varieties) may be compared, with each having little seed available. A so-called unreplicated trial has each new variety on just one plot at a site, but includes several replicated control varieties, making up around 10% and 20% of the trial. The aim of the trial is to choose some (usually around one third) good performing new varieties to go on for further testing, rather than precise estimation of their mean yields. Now that spatial analyses of data from field experiments are becoming more common, there is interest in an efficient layout of an experiment given a proposed spatial analysis and an efficiency criterion. Common optimal design criteria values depend on the usual C-matrix, which is very large, and hence it is time consuming to calculate its inverse. Since most varieties are unreplicated, the variety incidence matrix has a simple form, and some matrix manipulations can dramatically reduce the computation needed. However, there are many designs to compare, and numerical optimisation lacks insight into good design features. Some possible design criteria are discussed, and approximations to their values considered. These allow the features of efficient layouts under spatial dependence to be given and compared. (c) 2006 Elsevier Inc. All rights reserved.

BIBLIOTECA VIRTUAL: UMA ANÁLISE DOS FATORES ANTECEDENTES DA INTENÇÃO DE USO DOS ESTUDANTES DO ENSINO SUPERIOR

Diversos estudos sobre a aceitação e o uso de tecnologias de informação têm sido realizados por diferentes modelos conceituais que buscam demonstrar a existência de fatores que influenciam a intenção e comportamento dos usuários sobre um determinado sistema de informação. Alguns aspectos que potencializam as intenções de uso podem ser fundamentais para que o indivíduo adote, ou não, uma determinada tecnologia. Este estudo analisou os fatores antecedentes que podem influenciar a intenção de uso da Biblioteca Virtual de uma Instituição de Ensino Superior (IES). Dentre os modelos conceituais que estudam a adoção de tecnologias de informação, optou-se nesta pesquisa pelo Modelo de Aceitação de Tecnologia (TAM) proposto por Davis (1986). Neste modelo ainda foram adicionadas as variáveis externas Estímulo Docente e Hábito a fim de ampliar o poder de explicação da intenção de uso dos usuários em questão. Através de uma abordagem de investigação quantitativa, os dados foram coletados por meio de um instrumento de pesquisa com obtenção de resposta de 406 questionários. Os resultados obtidos por esta pesquisa confirmam a influência de diversos fatores posicionados em diferentes dimensões e proporcionam conclusões relevantes à adoção da biblioteca virtual. Conclui-se que o Estímulo Docente influencia positivamente a Facilidade de Uso, Utilidade Percebida e o Habito dos alunos de graduação sobre a intenção de uso da Biblioteca Virtual. Com isso, constatou-se que a influência do professor torna-se um fator determinante na intenção de uso da biblioteca virtual, o que ressalta a importância da orientação e recomendação dos professores no uso desta ferramenta tecnológica. O estudo concluiu que a utilidade percebida revelou-se o fator que mais influencia a intenção de uso desta tecnologia, pois há a percepção de que, caso o aluno venha utilizar a biblioteca virtual, pode-se melhorar seu desempenho nos estudos, entre outros aspectos. O Hábito também pode influenciar à adoção da biblioteca virtual de forma paralela às percepções sobre os benefícios que podem ser obtidos com o uso desta tecnologia.

Determining the influence of strategic planning's elements in its success

This paper presents the results of a multinational large-scale survey, investigating the current trends in strategic planning. The survey was conducted online using the Warwick Business School alumni database. Considering the development and implementation of strategy within a multi-process framework, the 'Strategic Development Process' model by Dyson and O'Brien (1998), using factor analysis, four distinct factors of strategic planning have been produced and with regression analysis, their impact on the success of strategic planning from a process point of view has been assessed. The results indicate that significant variation in practices involved is created by complexity either of the organizational size or environmental turbulence.

Representation and parameterisation issues in genetic algorithms

A multi-chromosome GA (Multi-GA) was developed, based upon concepts from the natural world, allowing improved flexibility in a number of areas including representation, genetic operators, their parameter rates and real world multi-dimensional applications. A series of experiments were conducted, comparing the performance of the Multi-GA to a traditional GA on a number of recognised and increasingly complex test optimisation surfaces, with promising results. Further experiments demonstrated the Multi-GA's flexibility through the use of non-binary chromosome representations and its applicability to dynamic parameterisation. A number of alternative and new methods of dynamic parameterisation were investigated, in addition to a new non-binary 'Quotient crossover' mechanism. Finally, the Multi-GA was applied to two real world problems, demonstrating its ability to handle mixed type chromosomes within an individual, the limited use of a chromosome level fitness function, the introduction of new genetic operators for structural self-adaptation and its viability as a serious real world analysis tool. The first problem involved optimum placement of computers within a building, allowing the Multi-GA to use multiple chromosomes with different type representations and different operators in a single individual. The second problem, commonly associated with Geographical Information Systems (GIS), required a spatial analysis location of the optimum number and distribution of retail sites over two different population grids. In applying the Multi-GA, two new genetic operators (addition and deletion) were developed and explored, resulting in the definition of a mechanism for self-modification of genetic material within the Multi-GA structure and a study of this behaviour.

Noise generated at the tyre/road interface

The work described in this thesis is directed towards the reduction of tyre/road interface noise and embodies a study of the factors involved in its generation. These factors comprise: (a) materials and construction of tyres and road surfaces (b) the spectral distribution of the noise. The importance of this work has become greater with reduction in engine noise. A review of the literature shows what has been achieved so far, and stresses the importance of maintaining other desirable tyre properties such as adhesion in wet conditions. The work has involved an analysis of mechanical factors in tyre construction and the behaviour of road surfaces. Measurements on noise have been carried out under practical conditions and also on replica surfaces in the laboratory, and in addition tests of wet road adhesion have been carried out with a variety of road surfaces. Consideration has been given to the psychological effects of the spectral distribution of noise. A major part of the work under-taken has been the development of a computer program, the results of which have made it possible to design a tyre tread block pattern to give an optimum spectral distribution. Sample tyres built to this design have been subjected to noise measurements and these have been shown to agree closely with the theoretical prediction and other properties of this tyre have proved to be satisfactory.

Knowledge, capabilities and manufacturing innovation: a US-Europe comparison

In this paper we report a comparative analysis of the factors which contribute to the innovation performance of manufacturing firms in the US state of Georgia, and three European regions, the UK regions of Wales and the West Midlands, and the Spanish region of Catalonia. We consider the factors which shape firms’ ability to generate new products and processes and undertake various forms of organisational and structural change. We are particularly concerned with how firms collect the knowledge on which they base their innovation and their effectiveness in translating that knowledge into new innovations. Three main empirical conclusions result. First, US firms have more widespread links to external knowledge sources than those in Europe and notably the universities make a greater contribution to innovation in the US than in Europe. Second, UK firms prove more effective at capturing synergies between their innovation activities than US and Catalan firms. Third, firms’ operating environment proves more conducive to innovation in the US than in either the UK regions or Catalonia. Our results suggest the potential for mutual learning. For the UK there are lessons in terms of the way in which the universities in Georgia are supporting innovation. For firms in Georgia and in Catalonia the potential lessons are more strategic or organisational and relate to how they can better capture potential synergies between their innovation activities.

Adoption of e-business solutions in food supply chains

The aim of this chapter is to increase understanding of e-business adoption in the food supply chain. In the first part of the paper an analysis of the concept and the context of e-business are presented along with a classification of the various e-business applications based on the dimensions of involvement and complexity. Next emphasis is given to the issue of e-business adoption. In particular an analysis of the factors that influence the adoption process is provided by exploring the specific characteristics of the food industry as well as the potential impact of the use of e-business solutions. These factors are not only related to the company but also to the supply chain of each company and the actual value of e-business applications. The chapter concludes that in many cases e-business is wrongly considered as a sole application and its adoption as mainly an intra-firm issue. Finally future trends are considered and discussed. © 2010 Woodhead Publishing Limited All rights reserved.