30 research outputs found

    Vacuum phototriodes for the CMS electromagnetic calorimeter endcap

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    The measurement of scintillation light from the lead tungstate crystals of the Compact Muon Solenoid (CMS) electromagnetic calorimeter (ECAL) poses a substantial technical challenge, particularly in the endcap regions, where the radiation levels are highest. The photodetectors must be fast, sensitive, radiationhard, and operate with significant internal gain in a magnetic field of 4 Tesla. The measured performance characteristics of the first batches of series production vacuum phototriodes (VPT), developed to satisfy the needs of CMS, will be described

    An ecological theory of learning transfer in human activity

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    All theoretical approaches to learning transfer assume some form of similarity. Behavioral science has, however, conceptualised similarity in superficial terms. Furthermore, no transfer theory has been developed to account for the full range of skills deployed in operational or intellectual activities. Dynamical systems theory is, at its core, a similarity theory. We leverage from a dynamical systems account of human activity to outline a theory of transfer that views repeatable patterns of behavior as macroscale properties that emerge from interactions between microscale processes of perception, cognition, and action. Dynamic coordination’s constitute solutions to goal directed activity and as such, must be tuned to the affordance structure of the situation and to the capabilities of the agent. Learning transfer, defined as improved performance on a criterion activity from prior experience on another activity, is contingent on improved detection and use of crucial affordances because of that prior experience. We bring together arguments relating to similarity, behavioral dynamics, affordances, learning, and analysis at both macroscales and microscales to identify potentially transferable elements of authentic, multifaceted activities that demand an appreciable level of skill.</p

    A whole-cell biosensor for the detection of gold

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    Geochemical exploration for gold (Au) is becoming increasingly important to the mining industry. Current processes for Au analyses require sampling materials to be taken from often remote localities. Samples are then transported to a laboratory equipped with suitable analytical facilities, such as Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) or Instrumental Neutron Activation Analysis (INAA). Determining the concentration of Au in samples may take several weeks, leading to long delays in exploration campaigns. Hence, a method for the on-site analysis of Au, such as a biosensor, will greatly benefit the exploration industry. The golTSB genes from Salmonella enterica serovar typhimurium are selectively induced by Au(I/III)-complexes. In the present study, the golTSB operon with a reporter gene, lacZ, was introduced into Escherichia coli. The induction of golTSB::lacZ with Au(I/III)-complexes was tested using a colorimetric β-galactosidase and an electrochemical assay. Measurements of the β-galactosidase activity for concentrations of both Au(I)- and Au(III)-complexes ranging from 0.1 to 5 µM (equivalent to 20 to 1000 ng g⁻¹ or parts-per-billion (ppb)) were accurately quantified. When testing the ability of the biosensor to detect Au(I/III)-complexes(aq) in the presence of other metal ions (Ag(I), Cu(II), Fe(III), Ni(II), Co(II), Zn, As(III), Pb(II), Sb(III) or Bi(III)), cross-reactivity was observed, i.e. the amount of Au measured was either under- or over-estimated. To assess if the biosensor would work with natural samples, soils with different physiochemical properties were spiked with Au-complexes. Subsequently, a selective extraction using 1 M thiosulfate was applied to extract the Au. The results showed that Au could be measured in these extracts with the same accuracy as ICP-MS (P<0.05). This demonstrates that by combining selective extraction with the biosensor system the concentration of Au can be accurately measured, down to a quantification limit of 20 ppb (0.1 µM) and a detection limit of 2 ppb (0.01 µM).Carla M. Zammit, Davide Quaranta, Shane Gibson, Anita J. Zaitouna, Christine Ta, Joël Brugger, Rebecca Y. Lai, Gregor Grass, Frank Reit

    Dense, fast, radiation-tolerant Fluoro-Hafnate glass scintillators for electromagnetic calorimeters in high energy physics

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    Over 200 different compositions of heavy metal fluoride glasses have been produced and evaluated as possible candidates for the active medium in homogeneous electromagnetic calorimeters for high energy particles. Promising glasses, based on mixtures containing hafnium fluoride, have densities of 6 g/cm^3, radiation lengths of 1.6 cm, and good optical transmission from the UV to the IR. Glasses containing the Ce3+ ion are fast scintillators, with properties similar to those of pure cerium fluoride crystal. We have made glasses which have up to 14% of the light yield of CeF3, fast scintillation characterised by typical exponential decay constants of 10 ns and 25 ns, and a temperature dependence of light yield of -0.4%/C over the range -10C to 60C. We have carried out a detailed investigation of the effects of gamma irradiation (up to doses of 6kGy) on the optical transmission, and systematic studies into the role of indium and other elements on radiation tolerance and light yield. Some glasses have shown complete optical annealing of radiation-induced absorbance when exposed to UV light.PPAR

    Airborne concentration and deposition of trace metals and metalloids in an urban area downwind of a manganese alloy plant

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    The evaluation of the content of metals and metalloids in particulate matter (PM) and in atmospheric deposition in areas impacted by local industries is essential from an environmental and health risk perspective. In this study, the PM10 levels and atmospheric deposition fluxes of potentially toxic metals and metalloids were quantified at three urban sites of the Cantabrian region (northern Spain), located at different distances downwind of a Mn alloy plant. The content of Mn, V, Fe, Ni, Cu, Zn, As, Mo, Cd, Sb and Pb in PM10 and in the water-soluble and insoluble fractions of the deposition was determined by ICP-MS. Among the studied elements, the highest concentrations in PM10 and deposition rates were found for Mn, Fe, Zn and Pb, associated with the Mn alloy industry, and for Cu, related to non-exhaust traffic emissions. The levels of Mn, Fe, Zn and Pb in PM10 were higher in autumn, when the most frequent winds blow from the S-SW, whereas their highest deposition rates were found in winter and autumn, which are characterized by high monthly average precipitations. The water-soluble fraction of the atmospheric deposition of most metals increased with distance from the Mn alloy plant. The highest water-soluble fractions were found for Ni (72%), Zn (62%), Cu (60%) and Mn (49%). These results will be useful for the health risk assessment of the metal exposure associated with Mn alloy plants, as well as for the evaluation of the metal burden to soil, water and ecosystems related to this industrial activity.This work was financially supported by the Spanish Ministry of Economy and Competitiveness (MINECO) through the CTM2013-43904R Project. Ana Hernández-Pellón would like to thank the Ministry of Economy and Competitiveness (MINECO) for the FPI grant awarded, reference number BES-2014-068790

    A Validated Model of Serum Anti-Müllerian Hormone from Conception to Menopause

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    Background Anti-Müllerian hormone (AMH) is a product of growing ovarian follicles. The concentration of AMH in blood may also reflect the non-growing follicle (NGF) population, i.e. the ovarian reserve, and be of value in predicting reproductive lifespan. A full description of AMH production up to the menopause has not been previously reported. Methodology/Principal Findings By searching the published literature for AMH concentrations in healthy pre-menopausal females, and using our own data (combined ) we have generated and robustly validated the first model of AMH concentration from conception to menopause. This model shows that 34% of the variation in AMH is due to age alone. We have shown that AMH peaks at age 24.5 years, followed by a decline to the menopause. We have also shown that there is a neonatal peak and a potential pre-pubertal peak. Our model allows us to generate normative data at all ages. Conclusions/Significance These data highlight key inflection points in ovarian follicle dynamics. This first validated model of circulating AMH in healthy females describes a transition period in early adulthood, after which AMH reflects the progressive loss of the NGF pool. The existence of a neonatal increase in gonadal activity is confirmed for females. An improved understanding of the relationship between circulating AMH and age will lead to more accurate assessment of ovarian reserve for the individual woman.Publisher PDFPeer reviewe

    Nursing home care for people with dementia and residents' quality of life, quality of care and staff well-being: Design of the Living Arrangements for people with Dementia (LAD) - study

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    <p>Abstract</p> <p>Background</p> <p>There is limited information available on how characteristics of the organization of nursing home care and especially group living home care and staff ratio contribute to care staff well being, quality of care and residents' quality of life. Furthermore, it is unknown what the consequences of the increasingly small scale organization of care are for the amount of care staff required in 2030 when there will be much more older people with dementia.</p> <p>Methods/Design</p> <p>This manuscript describes the design of the 'Living Arrangements for people with Dementia study' (LAD-study). The aim of this study is to include living arrangements from every part of this spectrum, ranging from large scale nursing homes to small group living homes. The LAD-study exists of quantitative and qualitative research. Primary outcomes of the quantitative study are wellbeing of care staff, quality of care and quality of life of residents. Furthermore, data concerning staff ratio and characteristics of the living arrangements such as group living home care characteristics are assessed. To get more in-depth insight into the barriers and facilitators in living arrangements for people with dementia to provide good care, focus groups and Dementia Care Mapping are carried out.</p> <p>Discussion</p> <p>Results of this study are important for policymakers, directors and staff of living arrangements providing nursing home care to people with dementia and essential for the development of methods to improve quality of care, residents' and staff well-being. Data collection will be repeated every two years, to generate knowledge on the results of changing policies in this field.</p

    Rapid Development of a Hospital Checklist in a Time of COVID-19

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    The discipline of human factors and ergonomics is largely focused on principled development of generalizable solutions. The process is typically slow, spanning months, even years. A crisis such as the COVID-19 pandemic presents a different problem. How can human factors and ergonomics professionals react quickly, within hours or days, to provide viable solutions to unanticipated problems as they become apparent? Here we report on a small project in which we were able to respond rapidly to an emergent COVID-19 requirement. Given time constraints, we had no opportunity to follow a systematic analysis and design strategy. Our development and testing strategies reveal lessons that can be applied more generally to development of human factors and ergonomics interventions within emerging crises. </jats:p
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