We describe the development of a charge-coupled device (CCD) array for use as a soft X-ray (0.4-12 keV) imaging spectrometer for the ASCA (formerly Astro-D) satellite. The CCDs are 420/spl ...times/420-pixel frame-transfer devices designed to be closely abutted to other chips on three sides of the imaging array. The imagers are made on 6500-/spl Omega//spl middot/cm p-type float-zone silicon for depletion depths of about 50 /spl mu/m under typical CCD bias conditions. The read noise of the CCD is typically 3-4 e/sup /spl minus// rms at data rates of 50 KHz resulting in an energy resolution E//spl delta/E/spl ap/50 at 5.9 keV. The complete focal-plane sensor consists of a 2/spl times/2 array of these devices mounted on a common substrate. Radiation damage from energetic protons is mitigated by the use of a narrow potential trough along the center of the CCD channel to confine the small X-ray event charge to a reduced volume and thereby minimize trapping effects. Charged-particle events from the non-X-ray space background are minimized by using a junction on the back of the chip to deplete most of the neutral bulk and draw background charge away from the CCD. Wafer-level device screening at low temperatures and the focal-plane packaging methods are also described.< >
Document assembly software is a technology that is fundamental to disrupting law firms. This article uses the framework set out by Clayton Christensen in The Innovator’s Dilemma and subsequent books ...to examine the range of business models that use document assembly software, from those that are sustaining in relation to law firms to those that are disruptive in relation to law firms. It looks at three barriers that slow down the pace of disruption: a shortage of the right people, rules against unauthorised practice, and inadequate capitalisation of law firms. These barriers will be overcome on a piecemeal basis as disruptive forces advance and undercut the billable hour.
Lung cancer (LC) is one of the most common causes of cancer death globally. Adults aged 55+, (ex)-smokers and living in areas of deprivation are at greater risk from lung cancer. Leading to a 20% ...decrease in mortality rates, screening with Low Dose CT (LDCT) is a promising means of detecting LC early. Autoantibody biomarker blood tests may play a role in identifying people suitable for LDCT screening, forming a national LCS programme. To increase the likelihood of the success of such a programme, suitable ways of providing the service must firstly be identified. A 2-phase co-design process, with 2 population groups. Group 1-Aged 55+, (ex)-smoker, high deprivation (N = 39). Group 2-Health and community professionals (N = 16). Phase 1: Interviews and focus groups. Conversations focussed on barriers, facilitators and potential pathways for the uptake and provision of a biomarker blood test and LCS. Phase 2: Interactive surveys (offline/online), focussing on the prioritisation of key barriers and solution generation. Qualitative data was transcribed and analysed using thematic analysis. Descriptive statistics were generated for quantitative data. Phase 1 identified key barriers, facilitators and pathways for uptake and provision. Service users indicated options for uptake and a means to embed the programme in the community as essential. From the perspective of providers, capacity and time for provision were key. Phase 2 found a home test kit was the preferred method of blood test for service users (independently or with assistance). Service providers leaned towards provision via venesection. Barriers were ranked by service users, the most dominant barrier was Fear of test result. Working in a collaborative manner has led to the identification of new knowledge and insights regarding the best means to target a future LCS programme to those who may benefit most. Future implementation of such a programme should consider the results from this study.
This is a CSO funded project.
Key messages
This process has illuminated key barriers, facilitators and pathway options that could improve the implementation of a LCS programme, using an autoantibody blood test to identify LDCT candidates.
Measures to overcome barriers from both the perspective of the service users and providers are necessary to ensure the success of the LCS programme.
Pollen, a regular component of tropical ice cores, has been shown to have great potential as a sensitive paleoenvironmental proxy in ice-core research. However, questions remain as to the modern ...dispersal and depositional patterns of pollen on high-alpine tropical ice caps. This information is vital to the accurate interpretation of the environmental reconstructions being derived from fossil pollen. In this study, 11 surface snow samples were collected around the caldera rim at the summit of Mt. Parinacota along the Bolivian-Chilean border. Results show that pollen concentration and assemblage are uniform in samples taken from the southwestern quadrant and the entire eastern half of the mountain. However, the pollen signatures are significantly different in the northwestern quadrant, probably due to long-distance transport of xerophytic Compositae shrub pollen from the prevailing winds. The sections of the mountain not directly impacted by the prevailing northwesterlies reflect a more locally influenced pollen assemblage dominated by grasses. These results are consistent with previous findings from the Quelccaya Ice Cap and confirm the importance of the prevailing winds in the dispersal and deposition of pollen on these high-alpine tropical ice caps.
Data collected between 1974 and 2016 from snow pits and core samples from two Peruvian ice fields demonstrate the effect of the recent warming over the tropical Andes, augmented by El Niño, on the ...preservation of the climate record. As the 0°C isotherm is approaching the summit of the Quelccaya ice cap in the Andes of southern Peru (5,670 meters above sea level (masl)), the distinctive seasonal δ18O oscillations in the fresh snow deposited within each thermal year are attenuated at depth due to melting and percolation through the firn. This has become increasingly pronounced over 43 years. In the Andes of northern Peru, the ice field on the col of Nevado Huascarán (6050 masl) has retained its seasonal δ18O variations at depth due to its higher elevation. During the 2015/2016 El Niño, snow on Quelccaya and Huascarán was isotopically (δ18O) enriched and the net sum of accumulation over the previous year (NSA) was below the mean for non–El Niño years, particularly on Quelccaya (up to 64% below the mean) which was more pronounced than the NSA decrease during the comparable 1982/1983 El Niño. Interannual large‐scale oceanic and middle to upper‐level atmospheric temperatures influence δ18O in precipitation on both ice fields, although the influences are variably affected by strong El Niño–Southern Oscillation events, especially on Quelccaya. The rate of ice wastage along Quelccaya's margin was dramatically higher during 2015/2016 compared with that of the previous 15 years, suggesting that warming from future El Niños may accelerate mass loss on Peruvian glaciers.
Key Points
Midtropospheric warming in the Peruvian Andes is destroying climate signals preserved in glaciers and driving glacier retreat
The impact of the 2015/2016 El Niño on Quelccaya ice cap was more pronounced than for previous events in the last four decades
Peruvian Andes snow δ18O is linked to tropical Pacific SSTs, regional 500 mb temperatures, and convection
Hydration for a Series of Hydrocarbons Mountain, Raymond D.; Thirumalai, D.
Proceedings of the National Academy of Sciences - PNAS,
07/1998, Letnik:
95, Številka:
15
Journal Article
Recenzirano
Odprti dostop
The hydrophobic hydration in a series of hydrocarbons is probed by using molecular dynamics simulations. The solutes considered range from methane to octane. Examination of the shapes of the ...hydration shell suggests that there is no single stable structure surrounding these solutes. The structure of the water molecules around the solute is not significantly perturbed, even for octane, and the hydrogen bond network is essentially preserved. The solutes are accommodated in the voids of the tetrahedral network of water in such a way as to leave the local environment almost intact. The hydrophobic hydration arises primarily because of the plasticity of the hydrogen bond network. Even for octane we find very little evidence for water-mediated interactions between nonbonded carbon atoms, leading us to suggest that the transition to globular conformations can only occur for very long, linear hydrocarbon chains.
The industrial fluid properties simulation challenge was established in 2001 to provide a realistic assessment of the value of molecular simulation methods for predicting thermophysical properties of ...industrially important fluids. The organizing committee (the authors of this paper) wished to establish reliable comparisons between the available methods, to assess the state of the art, and to enhance alignment of academic efforts with industrial needs. The first contest was held in 2002. Commercial modeling companies, academic groups and government laboratories were challenged to predict vapor–liquid equilibria, densities, and viscosities for a specified set of organic fluids, mixtures and aqueous solutions. Based on the success of that endeavor a second contest was held, concluding in September 2004. Modeling groups from around the world attempted to predict vapor pressure and heats of vaporization, Henry's law constants, and heats of mixing using molecular simulation methods (the focus of this contest). The contestants applied a wide range of different methods, and different forcefields. Accurate benchmark values were obtained, based on experimental data, by a team from NIST and Dow Chemical and used to assess the accuracy of the predicted values. Predictions of Henry's constant were judged sufficiently accurate to be of value in an industrial environment. The results for vapor pressure and heats of vaporization were mixed. Reasonable qualitative predictions of heats of mixing were obtained for an organic/organic mixture. But results for aqueous solutions revealed an area where although, for the most part, the methods by which predictions were made are sound, the forcefield descriptions are inadequate.
Plasma cell mucositis: a review and case report Smith, M. E.; Crighton, A. J.; Chisholm, D. M. ...
Journal of oral pathology & medicine,
April 1999, Letnik:
28, Številka:
4
Journal Article
Recenzirano
The simultaneous involvement of the mucous membranes of the oral cavity and upper aerodigestive tract by lesions characterised clinically by an intensely erythematous, lobulated surface and ...histologically by a dense connective tissue in‐ Key words: plasma cell mucositis filtrate composed of non‐neoplastic plasma cells may be called plasma cell mucositis. We present a review of the literature, consisting of 14 cases, outlining the Malvin Smith, Unit of Oral Medicine and multifocal site distribution, chronicity and systemic background that distin‐ Surgery, Dental School, Park Place, Dundee, DD1 4HR, Scotland guish this entity and report a single case with confirmation of the polyclonal nature of the plasma cell infiltrate using gene rearrangement studies.
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