4,484 research outputs found
Impact of Information and Communication Technology (ICT) on construction projects
The changing face of construction projects has resulted in a movement towards the use of technology as a primary means of communication. The consequences of this rise in the use of information and communication technology (ICT) is a loss of interpersonal communication skills. A number of resulting issues within the human – electronic and human – human interfaces are identified in an attempt to define the efficiency of communication in projects. The research shows how ICT effects the social environment of construction project teams and the project outcome. The study seeks to confirm the need for further work in order to develop new forms of communication protocols and behaviour. An initial literature review was undertaken to develop a theoretical review of the impacts of ICT on construction project teams. This review identified a number of issues that were then tested in the field through an observation and two verification interviews. The research confirms the existence of tensions and conflicts in the human – electronic and human - human communication interfaces within the studies environment. It is proposed that the increasing use of ICT occur at the expense of soft system communication. The principal impact of this is a form of ‘human distraction’ which adversely affects the performance of project teams. There is limited theory exploring these issues that suggests the problems identified are not well understood and consequently indicates a gap in knowledge
Are Asset Demand Functions Determined by CAPM?
The Capital Asset Pricing Model (CAPH) says that the responsiveness of asset-demands to expected returns depends (inversely) on the variance-covariance matrix of returns, rather than being an arbitrary set of parameters.Previous tests of CAPM have usually computed covariances of returns around sample means, and then checked whether the riskier assets are those with the higher mean returns. We offer a new technique for testing CAPM. The technique requires the use of time series data on actual asset-holdings, and non-linear maximum likelihood estimation. We claim superiority to earlier tests on three grounds. (1) We allow expected returns to vary freely overtime.(2) The alternative hypothesis is well-specified: asset-demands are linear functions of expected returns that do not depend on the variance-covariance matrix.(3) The test-statistic has a known distribution; it is simply a likelihood ratio test. We try the technique on yearly data, 1954-1980, for household holdings of a portfolio of six assets: short-term bills and deposits, tangible assets, federal debt, state and local debt, corporate debt, and equities. Our test rejects the CAPM hypothesis.
Near-Rational Wage and Price Setting and the Long-Run Phillips Curve
macroeconomics, Near-Rational Wage, Price Setting, Long-Run Phillips Curve
Temperature-stable Gunn-diode oscillator
Oscillator consisting of Gunn diode embedded in coaxial circuit has excellent temperature stability and low fabrication costs as compared with automatic-frequency-control crystal oscillators
Genome-wide mapping reveals single-origin chromosome replication in Leishmania, a eukaryotic microbe
Background
DNA replication initiates on defined genome sites, termed origins. Origin usage appears to follow common rules in the eukaryotic organisms examined to date: all chromosomes are replicated from multiple origins, which display variations in firing efficiency and are selected from a larger pool of potential origins. To ask if these features of DNA replication are true of all eukaryotes, we describe genome-wide origin mapping in the parasite Leishmania.
Results
Origin mapping in Leishmania suggests a striking divergence in origin usage relative to characterized eukaryotes, since each chromosome appears to be replicated from a single origin. By comparing two species of Leishmania, we find evidence that such origin singularity is maintained in the face of chromosome fusion or fission events during evolution. Mapping Leishmania origins suggests that all origins fire with equal efficiency, and that the genomic sites occupied by origins differ from related non-origins sites. Finally, we provide evidence that origin location in Leishmania displays striking conservation with Trypanosoma brucei, despite the latter parasite replicating its chromosomes from multiple, variable strength origins.
Conclusions
The demonstration of chromosome replication for a single origin in Leishmania, a microbial eukaryote, has implications for the evolution of origin multiplicity and associated controls, and may explain the pervasive aneuploidy that characterizes Leishmania chromosome architecture
Inflation and Unemployment in the U.S. and Canada: A Common Framework
This paper summarizes the results of our efforts to broaden the theory of the Phillips curve and to explain the joint evolution of inflation and unemployment in the United States and Canada since 1930.Phillips curve, unemployment, inflation
Why has it been so difficult to prove the efficacy of alpha-1-antitrypsin replacement therapy? Insights from the study of disease pathogenesis
Alpha-1-antitrypsin is the most abundant circulating protease inhibitor. It is mainly produced by the liver and secreted into the circulation where it acts to prevent excessive proteolytic damage in the lungs by the enzyme neutrophil elastase. The most common severe deficiency allele is the Z mutation, which causes the protein to self-associate into ordered polymers. These polymers accumulate within hepatocytes to cause liver damage. The resulting lack of circulating α1-antitrypsin predisposes the Z homozygote to proteolytic lung damage and emphysema. Other pathways may also contribute to the development of lung disease. In particular, polymers of Z α1-antitrypsin can form within the lung where they act as a pro-inflammatory stimulus that may exacerbate protease-mediated lung damage. Researchers recognized in the 1980s that plasma α1-antitrypsin levels could be restored by intravenous infusions of purified human protein. Alpha-1-antitrypsin replacement therapy was introduced in 1987 but subsequent clinical trials have produced conflicting results, and to date there remains no widely accepted clinical evidence of the efficacy of α1-antitrypsin replacement therapy. This review addresses our current understanding of disease pathogenesis in α1-antitrypsin deficiency and questions why this treatment in isolation may not be effective. In particular it discusses the possible role of α1-antitrypsin polymers in exacerbating intrapulmonary inflammation and attenuating the efficacy of α1-antitrypsin replacement therapy
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GRIDCC: Real-time workflow system
The Grid is a concept which allows the sharing of resources between distributed communities, allowing each to progress towards potentially different goals. As adoption of the Grid increases so are the activities that people wish to conduct through it. The GRIDCC project is a European Union funded project addressing the issues of integrating instruments into the Grid. This increases the requirement of workflows and Quality of Service upon these workflows as many of these instruments have real-time requirements. In this paper we present the workflow management service within the GRIDCC project which is tasked with optimising the workflows and ensuring that they meet the pre-defined QoS requirements specified upon them
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