1,826 research outputs found

    Taking forward public procurement reforms in Ghana

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    The construction industry in Ghana, like many others worldwide, has had its fair share of damning independent reviews. Huge and unsustainable foreign debt, excessive budget deficits, huge contractual payment arrears, poor construction performance, corruption and pressure from international financial institutions, forced the government to commit to a reform of public procurement, which culminated in the passing of the Public Procurement Act, 2003 (Act 663). The paper outlines the events leading to, and features of, the public procurement reform in Ghana and analyses its potential impact and the unique challenges it presents. Comparisons are also drawn from relevant scenarios in other countries. The paper concludes that while the Procurement Act sets out the legal, institutional and regulatory framework to secure fiscal transparency and public accountability, the sole reliance on traditional contracting and price-based selection limits the scope for the value for money achievable. Expanding the reforms to cover procurement and project delivery methods and strategies, with a focus on ‘best value’, will increase the potential and likelihood of achieving value for money in public construction in Ghana

    The Effects of Pre-service Training and Experience on Preparation for the Principalship in England.

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    This paper provides a synopsis of the findings of a national survey of headteachers conducted during 1999 by means of a self-completion postal questionnaire. The survey sought to establish the perceptions of English headteachers with regard to their state of readiness on taking up the role. Where respondents reported themselves as well prepared or extremely well prepared for aspects of their role they were asked to attribute their perceived state of readiness to training, experience, or a combination of the two. In addition respondents were asked to complete open-ended questions which asked them to identify activities and support which would help the induction of newly appointed headteachers working in the special education sector

    Spectral fluctuations of tridiagonal random matrices from the beta-Hermite ensemble

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    A time series delta(n), the fluctuation of the nth unfolded eigenvalue was recently characterized for the classical Gaussian ensembles of NxN random matrices (GOE, GUE, GSE). It is investigated here for the beta-Hermite ensemble as a function of beta (zero or positive) by Monte Carlo simulations. The fluctuation of delta(n) and the autocorrelation function vary logarithmically with n for any beta>0 (1<<n<<N). The simple logarithmic behavior reported for the higher-order moments of delta(n) for the GOE (beta=1) and the GUE (beta=2) is valid for any positive beta and is accounted for by Gaussian distributions whose variances depend linearly on ln(n). The 1/f noise previously demonstrated for delta(n) series of the three Gaussian ensembles, is characterized by wavelet analysis both as a function of beta and of N. When beta decreases from 1 to 0, for a given and large enough N, the evolution from a 1/f noise at beta=1 to a 1/f^2 noise at beta=0 is heterogeneous with a ~1/f^2 noise at the finest scales and a ~1/f noise at the coarsest ones. The range of scales in which a ~1/f^2 noise predominates grows progressively when beta decreases. Asymptotically, a 1/f^2 noise is found for beta=0 while a 1/f noise is the rule for beta positive.Comment: 35 pages, 10 figures, corresponding author: G. Le Cae

    Optimal Determination of Size and Site of DGs in Mesh System Using PSO

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    Nowadays, the penetration of Distributed Generation (DG) in power networks takes special place for them worldwide and is increasing in developed countries. In order to improve of voltage profile, stability, reduction of power losses and etc, it is necessary that this increasing of installation of DGs in Distribution system should be becomes systematically. This paper introduces an optimal placement method in order to sizing and sitting of distributed generation in IEEE 30 bus mesh test system. The algorithm for optimization is Particle Swarm Optimization (PSO). Proposed objective function is Multi Objective Function that considers active power losses of the system and the voltage profile. High performance of the proposed algorithm is proved by applying algorithm in 30 bus IEEE system using MATLAB software and in order to illustrate of feasibility of proposed method this optimization will achieved with Three DG units

    A Study of Competence in Mathematics and Mechanics in an Engineering Curriculum

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    Professional bodies expect engineers to show competence in both mathematics and engineering topics such as mechanics, using their abilities in both of these to solve problems. Yet within engineering programmes there is a phenomena known as ‘The Mathematics Problem’, with students not demonstrating understanding of the subject. This paper will suggest that students are constructing different concept images in engineering and mathematics, based on their perception of either the use or exchange value for the topics. Using a mixed methods approach, the paper compares ten different types of concept image constructed by students, which suggests that familiar procedural images are preferred in mathematics. In contrast strategic and conceptual images develop for mechanics throughout the years of the programme, implying that different forms of competence are being constructed by students between the two subjects. The paper argues that this difference is attributed to the perceived use-value of mechanics in the career of the engineer, compared to the exchange-value associated with mathematics. Questions are raised about the relevance of current definitions of competence given that some routine mathematical operations previously performed by engineers are now being replaced by technology, in the new world of work

    Electrochemical titrations and reaction time courses monitored in situ by magnetic circular dichroism spectroscopy

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    Magnetic circular dichroism (MCD) spectra, at ultraviolet–visible or near-infrared wavelengths (185–2000 nm), contain the same transitions observed in conventional absorbance spectroscopy, but their bisignate nature and more stringent selection rules provide greatly enhanced resolution. Thus, they have proved to be invaluable in the study of many transition metal-containing proteins. For mainly technical reasons, MCD has been limited almost exclusively to the measurement of static samples. But the ability to employ the resolving power of MCD to follow changes at transition metal sites would be a potentially significant advance. We describe here the development of a cuvette holder that allows reagent injection and sample mixing within the 50-mm-diameter ambient temperature bore of an energized superconducting solenoid. This has allowed us, for the first time, to monitor time-resolved MCD resulting from in situ chemical manipulation of a metalloprotein sample. Furthermore, we report the parallel development of an electrochemical cell using a three-electrode configuration with physically separated working and counter electrodes, allowing true potentiometric titration to be performed within the bore of the MCD solenoid

    Design management: changing roles of the professions

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    This paper sets out to explore how recent changes in procurement in construction have affected the roles that professions play in the design process. It discusses how professions that traditionally took the role of design manager now find themselves participating within previously unforeseen contexts, working in multidisciplinary teams led by contractors and with changed responsibilities at the design stage. Supply chain members who were not previously involved during the early project phases are being engaged at the earliest phases of the project life cycle and even taking leadership roles while designers sometimes work as supply chain partners. A study of design in construction and other sectors shows that in dealing with design management issues it is critical to deepen appreciation for the unique characteristics of design and the design process. The paper argues that contractors and designers taking on design management roles in a dynamic industry seeking to explore best practice and innovative approaches to procurement and in the delivery of projects need to acquire new skills, management education and develop the necessary qualities

    Structural analysis of pathogenic mutations in the DYRK1A gene in patients with developmental disorders.

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    Haploinsufficiency in DYRK1A is associated with a recognizable developmental syndrome, though the mechanism of action of pathogenic missense mutations is currently unclear. Here we present 19 de novo mutations in this gene, including five missense mutations, identified by the Deciphering Developmental Disorder study. Protein structural analysis reveals that the missense mutations are either close to the ATP or peptide binding-sites within the kinase domain, or are important for protein stability, suggesting they lead to a loss of the protein's function mechanism. Furthermore, there is some correlation between the magnitude of the change and the severity of the resultant phenotype. A comparison of the distribution of the pathogenic mutations along the length of DYRK1A with that of natural variants, as found in the ExAC database, confirms that mutations in the N-terminal end of the kinase domain are more disruptive of protein function. In particular, pathogenic mutations occur in significantly closer proximity to the ATP and the substrate peptide than the natural variants. Overall, we suggest that de novo dominant mutations in DYRK1A account for nearly 0.5% of severe developmental disorders due to substantially reduced kinase function

    Rapid prenatal diagnosis using targeted exome sequencing: a cohort study to assess feasibility and potential impact on prenatal counseling and pregnancy management.

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    Purpose Unexpected fetal abnormalities occur in 2-5% of pregnancies. While traditional cytogenetic and microarray approaches achieve diagnosis in around 40% of cases, lack of diagnosis in others impedes parental counseling, informed decision making, and pregnancy management. Postnatally exome sequencing yields high diagnostic rates, but relies on careful phenotyping to interpret genotype results. Here we used a multidisciplinary approach to explore the utility of rapid fetal exome sequencing for prenatal diagnosis using skeletal dysplasias as an exemplar. Methods Parents in pregnancies undergoing invasive testing because of sonographic fetal abnormalities, where multidisciplinary review considered skeletal dysplasia a likely etiology, were consented for exome trio sequencing (both parents and fetus). Variant interpretation focused on a virtual panel of 240 genes known to cause skeletal dysplasias. Results Definitive molecular diagnosis was made in 13/16 (81%) cases. In some cases, fetal ultrasound findings alone were of sufficient severity for parents to opt for termination. In others, molecular diagnosis informed accurate prediction of outcome, improved parental counseling, and enabled parents to terminate or continue the pregnancy with certainty. Conclusion Trio sequencing with expert multidisciplinary review for case selection and data interpretation yields timely, high diagnostic rates in fetuses presenting with unexpected skeletal abnormalities. This improves parental counseling and pregnancy management.Genetics in Medicine advance online publication, 29 March 2018; doi:10.1038/gim.2018.30
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