17,361 research outputs found

    Characterization of the Noise in Secondary Ion Mass Spectrometry Depth Profiles

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    The noise in the depth profiles of secondary ion mass spectrometry (SIMS) is studied using different samples under various experimental conditions. Despite the noise contributions from various parts of the dynamic SIMS process, its overall character agrees very well with the Poissonian rather than the Gaussian distribution in all circumstances. The Poissonian relation between the measured mean-square error (MSE) and mean can be used to describe our data in the range of four orders. The departure from this relation at high counts is analyzed and found to be due to the saturation of the channeltron used. Once saturated, the detector was found to exhibit hysteresis between rising and falling input flux and output counts.Comment: 14 pages, 4 postscript figures, to appear on J. Appl. Phy

    Stigma: a linguistic analysis of the UK red-top tabloids press’s representation of ‘schizophrenia’

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    Aims. Media representations of mental health problems may influence readers’ understanding of, and attitude towards, people who have received psychiatric diagnoses. Negative beliefs and attitudes may then lead to discriminatory behaviour, which is understood as stigma. This study explored the language used in popular national newspapers when writing about schizophrenia and considered how this may have contributed to the processes of stigmatisation towards people with this diagnosis. Methods. Using corpus linguistic methods, a sample of newspaper articles over a 24 month period that mentioned the word ‘schizophrenia’ was compared with a similar sample of articles about diabetes. This enabled a theory-driven exploration of linguistic characteristics to explore stigmatising messages, whilst supported by statistical tests (Log-Likelihood) to compare the data sets and identify words with a high relative frequency. Results. Analysis of the ‘schizophrenia’ data set identified that overtly stigmatising language (e.g. “schizo”) was relatively infrequent, but that there was frequent use of linguistic signatures of violence. Articles frequently used graphic language referring to: acts of violence, descriptions of violent acts, implements used in violence, identity labels and exemplars of well-known individuals who had committed violent acts. The word ‘schizophrenic’ was used with a high frequency (n=108) and most commonly to name individuals who had committed acts of violence. Discussion. The study suggests that whilst the press have largely avoided the use of words that press guidance has steered them away from (e.g. “schizo” and “psycho”) that they still use a range of graphic language to present people with a diagnosis of schizophrenia as frighteningly ‘other’ and as prone to violence. This repetition of negative stereotypical messages may well contribute to the processes of stigmatisation many people who experience psychosis have to contend

    Standardization and application of microsatellite markers for variety identification in tomato and wheat

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    The present study is part of a EU project that aims to demonstrate the technical viability of STMS markers for variety identification. As examples two important European crop species, tomato and wheat were chosen. Initially, about 30-40 STMS markers were used to identify a set of 20 good markers per crop and to standardise the methodology and the interpretation of the results in different laboratories. Several systems were used for the detection of STMS polymorphisms. The selected STMS markers are being tested on 500 varieties of each species and databases are being constructed. The first comparisons of data generated by the different laboratories revealed a high degree of agreement. The causes of discrepancies between duplicate samples analysed in different laboratories and precautions to prevent them, are discussed

    Composting paper and grass clippings with anaerobically treated palm oil mill effluent

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    Purpose The purpose of this study is to investigate the composting performance of anaerobically treated palm oil mill effluent (AnPOME) mixed with paper and grass clippings. Methods Composting was conducted using a laboratory scale system for 40 days. Several parameters were determined: temperature, mass reduction, pH, electrical conductivity, colour, zeta potential, phytotoxicity and final compost nutrients. Results The moisture content and compost mass were reduced by 24 and 18 %, respectively. Both final compost pH value and electrical conductivity were found to increase in value. Colour (measured as PtCo) was not suitable as a maturity indicator. The negative zeta potential values decreased from −12.25 to −21.80 mV. The phytotoxicity of the compost mixture was found to decrease in value during the process and the final nutrient value of the compost indicates its suitability as a soil conditioner. Conclusions From this study, we conclude that the addition of paper and grass clippings can be a potential substrate to be composted with anaerobically treated palm oil mill effluent (AnPOME). The final compost produced is suitable for soil conditioner

    NASA-JSC antenna near-field measurement system

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    Work was completed on the near-field range control software. The capabilities of the data processing software were expanded with the addition of probe compensation. In addition, the user can process the measured data from the same computer terminal used for range control. The design of the laser metrology system was completed. It provides precise measruement of probe location during near-field measurements as well as position data for control of the translation beam and probe cart. A near-field range measurement system was designed, fabricated, and tested

    Asynchronous displays for multi-UV search tasks

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    Synchronous video has long been the preferred mode for controlling remote robots with other modes such as asynchronous control only used when unavoidable as in the case of interplanetary robotics. We identify two basic problems for controlling multiple robots using synchronous displays: operator overload and information fusion. Synchronous displays from multiple robots can easily overwhelm an operator who must search video for targets. If targets are plentiful, the operator will likely miss targets that enter and leave unattended views while dealing with others that were noticed. The related fusion problem arises because robots' multiple fields of view may overlap forcing the operator to reconcile different views from different perspectives and form an awareness of the environment by "piecing them together". We have conducted a series of experiments investigating the suitability of asynchronous displays for multi-UV search. Our first experiments involved static panoramas in which operators selected locations at which robots halted and panned their camera to capture a record of what could be seen from that location. A subsequent experiment investigated the hypothesis that the relative performance of the panoramic display would improve as the number of robots was increased causing greater overload and fusion problems. In a subsequent Image Queue system we used automated path planning and also automated the selection of imagery for presentation by choosing a greedy selection of non-overlapping views. A fourth set of experiments used the SUAVE display, an asynchronous variant of the picture-in-picture technique for video from multiple UAVs. The panoramic displays which addressed only the overload problem led to performance similar to synchronous video while the Image Queue and SUAVE displays which addressed fusion as well led to improved performance on a number of measures. In this paper we will review our experiences in designing and testing asynchronous displays and discuss challenges to their use including tracking dynamic targets. © 2012 by the American Institute of Aeronautics and Astronautics, Inc

    The Ucsd/Keck Damped Lya Abundance Database: A Decade of High Resolution Spectroscopy

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    We publish the Keck/HIRES and Keck/ESI spectra that we have obtained during the first 10 years of Keck observatory operations. Our full sample includes 42 HIRES spectra and 39 ESI spectra along 65 unique sightlines providing abundance measurements on ~85 damped Lya systems. The normalized data can be downloaded from the journal or from our supporting website: http://www.ucolick.org/~xavier/DLA/. The database includes all of the sightlines that have been included in our papers on the chemical abundances, kinematics, and metallicities of the damped Lya systems. This data has also been used to argue for variations in the fine-structure constant. We present new chemical abundance measurements for 10 damped Lya systems and a summary table of high-resolution metallicity measurements (including values from the literature) for 153 damped Lya systems at z>1.6. We caution, however, that this metallicity sample (and all previous ones) is biased to higher N(HI) values than a random sample.Comment: 55 pages, 11 figures. Accepted to ApJS. See http://www.ucolick.org/~xavier/DLA/ for the dat
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