4,093 research outputs found

    The planning and control of multiple task work: a study of secretarial office administration

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    This paper reports an attempt to construct a design-oriented model of the planning and control of multiple task work (PCMT) based on observations of secretarial office administration (SOA). The model is design-oriented in that it is intended to assist a designer to reason about the behaviours of an interactive human-computer worksystem; in this case, the planning and control behaviours of worksystems which carry out multiple task work. Design-oriented models of engineering contrast with the understanding-oriented models of science, which offer an understanding of phenomena in the form of their explanation and prediction

    Precise measurement of positronium hyperfine splitting using the Zeeman effect

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    Positronium is an ideal system for the research of the quantum electrodynamics (QED) in bound state. The hyperfine splitting (HFS) of positronium, ΔHFS\Delta_{\mathrm{HFS}}, gives a good test of the bound state calculations and probes new physics beyond the Standard Model. A new method of QED calculations has revealed the discrepancy by 15\,ppm (3.9σ\sigma) of ΔHFS\Delta_{\mathrm{HFS}} between the QED prediction and the experimental average. There would be possibility of new physics or common systematic uncertainties in the previous all experiments. We describe a new experiment to reduce possible systematic uncertainties and will provide an independent check of the discrepancy. We are now taking data and the current result of ΔHFS=203.395 1±0.002 4(stat.,12 ppm)±0.001 9(sys.,9.5 ppm) GHz\Delta_{\mathrm{HFS}} = 203.395\,1 \pm 0.002\,4 (\mathrm{stat.}, 12\,\mathrm{ppm}) \pm 0.001\,9 (\mathrm{sys.}, 9.5\,\mathrm{ppm})\,\mathrm{GHz} has been obtained so far. A measurement with a precision of OO(ppm) is expected within a year.Comment: 8 pages, 8 figures, 2 tables, proceeding of LEAP2011, accepted by Hyperfine Interaction

    Transverse Cerebellar Diameter On Cranial Ultrasound Scan In Preterm Neonates In An Australian Population

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    Objective: Fetal measurement of transverse cerebellar diameter (TCD) has been shown to correlate well with gestational age (GA), even in the presence of growth retardation. The aim of this study was to define the normal range of TCD in preterm neonates in an Australian population between 23 and 32 weeks GA. Methodology: Infants admitted to the Royal Women's Hospital, Melbourne, having routine cranial ultrasound scans (< 1500 g and/or of gestational age 32 weeks at birth) had their TCD measured on a cranial scan performed during the first 3 days of life. The posterior fossa was examined through the asterion using a General Electric LOGIQ 500 scanner (GE Medical Systems, Waukesha, USA) and TCD measurement was taken in the coronal plane. Results: 106 infants < 1500 g and/or of GA 32 weeks at birth had their TCD measured between 1 January 1997 and 30 November 1997. Transverse cerebellar diameter and associated 95% confidence intervals are described for infants between 23 and 32 weeks GA. The linear regression equation relating TCD and GA was: TCD (mm) = 12.9 + 1.61 GA (weeks). R2 = 0.80, P< 0.001. Conclusion: This is the only study of TCD measurement using cranial ultrasound in a group of preterm newborns, and forms the basis for nomograms of TCD which can be used as a tool to assist in the assessment of GA, even in growth-retarded preterm newborns, and in the diagnosis of cerebellar hypoplasia

    The orphan germinant receptor protein GerXAO (but not GerX3b) is essential for L-alanine induced germination in Clostridium botulinum Group II

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    Clostridium botulinum is an anaerobic spore forming bacterium that produces the potent botulinum neurotoxin that causes a severe and fatal neuro-paralytic disease of humans and animals (botulism). C. botulinum Group II is a psychrotrophic saccharolytic bacterium that forms spores of moderate heat resistance and is a particular hazard in minimally heated chilled foods. Spore germination is a fundamental process that allows the spore to transition to a vegetative cell and typically involves a germinant receptor (GR) that responds to environmental signals. Analysis of C. botulinum Group II genomes shows they contain a single GR cluster (gerX3b), and an additional single gerA subunit (gerXAO). Spores of C. botulinum Group II strain Eklund 17B germinated in response to the addition of L-alanine, but did not germinate following the addition of exogenous Ca2+-DPA. Insertional inactivation experiments in this strain unexpectedly revealed that the orphan GR GerXAO is essential for L-alanine stimulated germination. GerX3bA and GerX3bC affected the germination rate but were unable to induce germination in the absence of GerXAO. No role could be identified for GerX3bB. This is the first study to identify the functional germination receptor of C. botulinum Group II

    Validity and reliability of the Norwegian version of the Musculoskeletal Health Questionnaire in people on sick leave.

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    BACKGROUND: The Musculoskeletal Health Questionnaire (MSK-HQ) is a recently developed generic questionnaire that consists of 14 items assessing health status in people with musculoskeletal disorders. The objective was to translate and cross-culturally adapt the MSK-HQ into Norwegian and to examine its construct validity and reliability in people on sick leave with musculoskeletal disorders. METHODS: A prospective cohort study was carried out in Norway on people between 18 and 67 years of age and sick leave due to a musculoskeletal disorder. The participants were recruited through the Norwegian Labour and Welfare Administration during November 2018-January 2019 and responded to the MSK-HQ at inclusion and after four weeks. Internal consistency was assessed by Cronbach's alpha, and structural validity with a factor analysis. Construct validity was assessed by eight "a priori" defined hypotheses regarding correlations between the MSK-HQ and other reference scales. Correlations were analyzed by Spearman's- or Pearson's correlation coefficient and interpreted as high with values ≥ 0.50, moderate between 0.30-0.49, and low < 0.29. Reliability was tested with test-retest, standard error of measurement (SEM) and smallest detectable change (SDC). RESULTS: A total of 549 patients, mean age (SD) 48.6 (10.7), 309 women (56.3%), were included. The mean (SD) MSK-HQ sum scores (min-max 3-56) were 27.7 (8.2). Internal consistency was 0.86 and a three-factor structure was determined by factor analysis. Construct validity was supported by the confirmation of all hypotheses; high correlation with HRQOL, psychosocial risk profile, and self-perceived health; moderate correlation with physical activity, self-perceived work ability, and work presenteeism; and low correlation with the number of sick days. The test-retest reliability was good with an intraclass correlation coefficient of 0.83 (95% CI, 0.74-0.89), SEM was 2.3 and SDC 6.5. CONCLUSIONS: The Norwegian version of the MSK-HQ demonstrated high internal consistency, a three-factor structure, good construct validity and good test-retest reliability when used among people on sick leave due to musculoskeletal disorders

    A tool for functional brain imaging with lifespan compliance

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    The human brain undergoes significant functional and structural changes in the first decades of life, as the foundations for human cognition are laid down. However, non-invasive imaging techniques to investigate brain function throughout neurodevelopment are limited due to growth in head-size with age and substantial head movement in young participants. Experimental designs to probe brain function are also limited by the unnatural environment typical brain imaging systems impose. However, developments in quantum technology allowed fabrication of a new generation of wearable magnetoencephalography (MEG) technology with the potential to revolutionise electrophysiological measures of brain activity. Here we demonstrate a lifespan-compliant MEG system, showing recordings of high fidelity data in toddlers, young children, teenagers and adults. We show how this system can support new types of experimental paradigm involving naturalistic learning. This work reveals a new approach to functional imaging, providing a robust platform for investigation of neurodevelopment in health and disease

    Pneumococcal carriage in sub-Saharan Africa--a systematic review.

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    BACKGROUND: Pneumococcal epidemiology varies geographically and few data are available from the African continent. We assess pneumococcal carriage from studies conducted in sub-Saharan Africa (sSA) before and after the pneumococcal conjugate vaccine (PCV) era. METHODS: A search for pneumococcal carriage studies published before 2012 was conducted to describe carriage in sSA. The review also describes pneumococcal serotypes and assesses the impact of vaccination on carriage in this region. RESULTS: Fifty-seven studies were included in this review with the majority (40.3%) from South Africa. There was considerable variability in the prevalence of carriage between studies (I-squared statistic = 99%). Carriage was higher in children and decreased with increasing age, 63.2% (95% CI: 55.6-70.8) in children less than 5 years, 42.6% (95% CI: 29.9-55.4) in children 5-15 years and 28.0% (95% CI: 19.0-37.0) in adults older than 15 years. There was no difference in the prevalence of carriage between males and females in 9/11 studies. Serotypes 19F, 6B, 6A, 14 and 23F were the five most common isolates. A meta-analysis of four randomized trials of PCV vaccination in children aged 9-24 months showed that carriage of vaccine type (VT) serotypes decreased with PCV vaccination; however, overall carriage remained the same because of a concomitant increase in non-vaccine type (NVT) serotypes. CONCLUSION: Pneumococcal carriage is generally high in the African continent, particularly in young children. The five most common serotypes in sSA are among the top seven serotypes that cause invasive pneumococcal disease in children globally. These serotypes are covered by the two PCVs recommended for routine childhood immunization by the WHO. The distribution of serotypes found in the nasopharynx is altered by PCV vaccination

    Cardiorespiratory and perceptual responses to self-regulated and imposed submaximal arm-leg ergometry

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    Purpose: This study compared cardiorespiratory and perceptual responses to exercise using self-regulated and imposed power outputs distributed between the arms and legs. Methods Ten males (age 21.7 ± 3.4 years) initially undertook incremental arm-crank ergometry (ACE) and cycle ergometry (CYC) tests to volitional exhaustion to determine peak power output (Wpeak). Two subsequent tests involved 20-min combined arm–leg ergometry (ALE) trials, using imposed and self-regulated protocols, both of which aimed to elicit an exercising heart rate of 160 beats min−1. During the imposed trial, arm and leg intensity were set at 40% of each ergometer-specific Wpeak. During the self-regulated trial, participants were asked to self-regulate cadence and resistance to achieve the target heart rate. Heart rate (HR), oxygen uptake (V˙O2 ), pulmonary ventilation (V˙E ), and ratings of perceived exertion (RPE) were recorded continuously. Results As expected, there were no differences between imposed and self-regulated trials for HR, V˙O2 , and V˙E (all P ≥ 0.05). However, central RPE and local RPE for the arms were lower during self-regulated compared imposed trials (P ≤ 0.05). Lower RPE during the self-regulated trial was related to preferential adjustments in how the arms (33 ± 5% Wpeak) and legs (46 ± 5% Wpeak) contributed to the exercise intensity. Conclusions: This study demonstrates that despite similar metabolic and cardiovascular strain elicited by imposed and self-regulated ALE, the latter was perceived to be less strenuous, which is related to participants doing more work with the legs and less work with the arms to achieve the target intensity
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