4,631 research outputs found

    Everyday and prospective memory deficits in ecstasy/polydrug users

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    The impact of ecstasy/polydrug use on real-world memory (i.e. everyday memory, cognitive failures and prospective memory [PM]) was investigated in a sample of 42 ecstasy/polydrug users and 31 non-ecstasy users. Laboratory-based PM tasks were administered along with self-reported measures of PM to test whether any ecstasy/polydrug-related impairment on the different aspects of PM was present. Self-reported measures of everyday memory and cognitive failures were also administered. Ecstasy/polydrug associated deficits were observed on both laboratory and self-reported measures of PM and everyday memory. The present study extends previous research by demonstrating that deficits in PM are real and cannot be simply attributed to self-misperceptions. The deficits observed reflect some general capacity underpinning both time- and event-based PM contexts and are not task specific. Among this group of ecstasy/polydrug users recreational use of cocaine was also prominently associated with PM deficits. Further research might explore the differential effects of individual illicit drugs on real-world memory

    THE SPECTROSCOPY OF CRYSTAL DEFECTS - A COMPENDIUM OF DEFECT NOMENCLATURE

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    The authors bring together tables of current defect nomenclature and a summary of the rules actually practised (rather than idealised schemes) in choosing such labels for signals obtained with a range of spectroscopies. As well as providing a source of reference for the user lost in a maze of labels, the compilation also indicates parallels between similar defect species in very different systems (e.g. ice and quartz), even though the relationships may be far from obvious from the labels. The systems considered are all non-metals, namely ionic crystals (including oxides), silica, semiconductors (e.g. III-V and tetrahedrally coordinated II-VI), valence crystals (e.g. diamond, c-Si, a-Si) and other special hosts like ice and conducting polymers

    A metrics paradigm for object-oriented analysis and design.

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    For several years, the software industry has been affected by a problem called the software crisis. Many software developers have worked hard to determine remedies for this crisis. The crisis deals with products being produced over costs, behind schedule, with low quality, and not meeting customer satisfaction. Processes are being used which waste resources and build low quality products. In dealing with the software crisis, software practitioners have used many tools, methodologies, and metrics to help produce better products, save resources, and increase productivity. Metrics are meaningful measures used to determine how well software is being produced, where weaknesses are in products, processes, or resources, and indicate where to make improvements. Today, the most popular methodology is the Object-Oriented (00) methodology. Users of this methodology want to prove that it helps resolve the software crisis. There is a belief that 00 systems are developed earlier, easier to understand and maintain, and contain reusable components. However, without metrics, the effectiveness of the 00 approach cannot be proven. Metrics must be used to show if the process or resources being used is responsible for the success or failure of software development, if management of the process is responsible, if the complexity or size of the product being produced is responsible, or if a lack of communication or misunderstandings of requirements is responsible. There are many, many reasons why metrics are used and can be seen in this Thesis. Many metrics are being used for traditional software development methodologies that deal with processes, products, and resources. However, there is no metric paradigm for the 00 development methodology. But, there is a small set of metrics proposed for 00 programming. We provide a 00 metric paradigm that contains metrics grouped into nine categories. We grouped the metrics into categories to make the selection of a particular· metric easier. These nine metrics fit nicely into the 00 methodology. The metrics can be used to measure processes, products, and resources. We provide a size estimation method that helps determine progress, costs, quality, effort, complexity, and schedule. The metrics can be used to prove the effectiveness of the 00 methodology and indicate areas for further improvement

    Limitations on the extent of off-center displacements in TbMnO3 from EXAFS measurements

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    We present EXAFS data at the Mn K and Tb L3 edges that provide upper limits on the possible displacements of any atoms in TbMnO3. The displacements must be less than 0.005-0.01A for all atoms which eliminates the possibility of moderate distortions (0.02A) with a small c-axis component, but for which the displacements in the ab plane average to zero. Assuming the polarization arises from a displacement of the O2 atoms along the c-axis, the measured polarization then leads to an O2 displacement that is at least 6X10^{-4}A, well below our experimental limit. Thus a combination of the EXAFS and the measured electrical polarization indicate that the atomic displacements likely lie in the range 6X10^{-4} - 5X10^{-3}A.Comment: submitted to PRB; 11 pages (preprint form) 7 figure
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