Self-induced structure in the current-voltage characteristics of RSQUIDs

Resistive two-junction SQUIDs (RSQUIDs) made from high-temperature superconductors are being developed as narrow-linewidth tunable oscillators in the GHz frequency range. We present here the results of numerical simulation of RSQUIDs of this type. These studies have identified conditions where sub-harmonic steps and other features are apparent in the current-voltage characteristics, driven by the internally-generated heterodyne frequency. The behavior is sensitive to the frequency (set by the voltage across the resistive element in the RSQUID), the temperature and also the loop inductance. We have studied the effects of thermal noise on these features. We also assess how these effects might be observed, and consider how they might affect practical applications of high frequency heterodyne RSQUID oscillators

Simulation and measurement of hts josephson heterodyne oscillator

We report continuing investigations into practical applications of the ac Josephson effect as the basis for a voltage-tunable radio-frequency oscillator. We have previously demonstrated experimentally that useful power levels (10 s of nW) and linewidths of a few kHz can be achieved in the heterodyne output from a High-Temperature-Superconducting Resistive SQUID (HTS-RSQUID) operating in the frequency range 1-50 MHz. Those results were achieved with 2-junction R-SQUIDs incorporating current-biased shunt resistors of a few micro-ohms. We have now modified the fabrication procedures, and adjusted the shunt resistors and bias current values so that higher frequencies can be achieved. The Josephson junctions are of step-edge type, rather than the bi-crystal type used in our earlier work. The step-edge technique permits much more flexibility in the geometrical lay-out and utilizes the more cost-effective single-crystal MgO substrates. In the present paper, we report numerical simulations and experimental measurements on these devices in the frequency range up to 2 GHz

Managing chronic widespread pain in primary care : a qualitative study of patient perspectives and implications for treatment delivery

Funding The MUSICIAN trial was supported by an award from Arthritis Research UK, Chesterfield, UK. Grant number: 17292. The funding body approved the design of the study. They played no role in the collection, analysis, and interpretation of data or the writing of the manuscript.Peer reviewedPublisher PD

Les miasmes, les microbes et les médecines. La diffusion des idées anciennes et nouvelles dans l’Union médicale du Canada : le cas de la fièvre typhoïde (1872-1900)

Les dernières décennies du 19e siècle sont connues comme une période de transition importante dans le monde médicale. Les nouvelles découvertes ont révolutionné la façon de voir et de combattre les maladies. Les microbes, pas les miasmes, furent la cause des maladies, qui furent contrôlé plus avec les mesures sanitaires pour la prévention, que par les traitements miraculeuses. En dépouillant les articles sur la fièvre typhoïde dans la revue l’Union médicale du Canada entre 1872 et 1900 on constate que les médecins acceptaient rapidement quelques innovations importantes. Par contre, en ce qui concerne les innovations où leurs anciennes affirmations furent mises en doute, ou leur popularité auprès de la population mis en péril, certains médecins démontraient une hésitation d’accepter ces avances. Cette étude présente la coexistence des idées nouvelles avec des idées plus anciennes, qui continuaient à être diffusé, parfois des années après des découvertes importantes. Nous verrons comment ils furent finalement gagné aux idées nouvelles.The final decades of the 19th century have become known as a period of important transition in the medical world. New discoveries revolutionized the way diseases were seen and fought. Germs, not miasmas, caused disease and sanitary measures of prevention not miracle treatments controlled them. The articles in l’Union médicale du Canada, from 1872 to 1900 concerning typhoid fever reveal that doctors rapidly accepted some important innovations. However, when it came to innovations refuting their former theories or risking to jeopardize their popularity with the public, certain doctors hesitated to adopt the new theories. This study presents the coexistance of new ideas with the older ideas, which continued to be presented, sometimes years after important discoveries. This paper looks at how they were finally won over to the newer ideas

Treatment expectations but not preference affect outcome in a trial of CBT and exercise for pain

The following are members of the MUSICIAN study team: Gary Macfarlane (Principal Investigator), John McBeth (Investigator), Deborah Symmons (Investigator), Karina Lovell (investigator), Philip Keeley (Investigator), Phil Hannaford (Investigator), Chrysa Gkazinou (Trial manager), Marcus Beasley (Research Assistant), Elizabeth Jones (PhD student), Gordon Prescott (Statistician), and Steve Woby (Investigator). We are grateful to the practices and patients in Aberdeen city and Cheshire, which participated in the study: Carden medical centre, Elmbank medical practice, Great Western Road medical practice, Garthdee medical group, Readesmoor medical group practice, Lawton House surgery, Bollington medical practice, Park Lane surgery. The Scottish Primary Care Research Network facilitated access to patient information at the practices in Aberdeen city. Charlie Stockton was the study manager and Ashraf El-Metwally an Investigator during the setting up and for part of the conduct of the study. John Norrie was originally an investigator of the MUSICIAN study while Director of the Centre for Health Care Randomised Trials (CHART) at the University of Aberdeen. We are grateful for the input of members of the Health Services Research Unit (HSRU) at The University of Aberdeen in the conduct of the study: Alison MacDonald and Gladys McPherson. We are grateful to the project assistants who worked on the survey: Dev Acharya, Jennifer Bannister, Flora Joyce, Michelle Rein., Karen Kane, and Rowan Jasper. Alison Littlewood was responsible for study management at the Cheshire site. Finally, we thank the independent members of the trial steering committee (Professor Matthew Hotopf, Professor Tracey Howe, Professor Martin Underwood) and data monitoring committee (Dr. Marwan Bukhari, Professor Hazel Inskip, Dr. Chris Edwards). Funding details The study was funded by Arthritis Research UK, grant number 17292.Peer reviewedPublisher PD

Blood rheology, cardiovascular risk factors, and cardiovascular disease: The West of Scotland Coronary Prevention Study

The West of Scotland Coronary Prevention Study (WOSCOPS) showed that pravastatin reduced the risk of coronary heart disease (CHD) events in 6,595 middle-aged hypercholesterolaemic men aged 45-64 years without prior myocardial infarction followed for an average of 4.9 years. We hypothesised prospectively (a) that baseline levels of haemorheological variables were related to baseline and incident CHD and to mortality; and (b) that reduction in lipoproteins by pravastatin would lower plasma and blood viscosity, a potential contributory mechanism to CHD events. We therefore studied plasma and blood viscosity, fibrinogen, haematocrit, and blood cell counts at baseline and 1 year. At baseline, plasma and blood viscosity were related to risk factors, CHD measures, and claudication. On univariate analysis, baseline levels of all rheological variables (except platelet count) were related to incident CHD; CHD mortality; and total mortality. On multivariate analysis including baseline CHD and risk factors, plasma and blood viscosity, haematocrit and white cell count each remained significantly associated with incident CHD; while fibrinogen remained an independent predictor of mortality (all p<0.03). After one year, lipoprotein reduction by pravastatin was associated with significant reductions (about one quarter of a standard deviation) in plasma viscosity (mean difference 0.02 mPa.s, p<0.001) and in blood viscosity (mean difference 0.06 mPa.s, p<0.001), but was not associated with significant changes in other rheological variables. We therefore suggest that pravastatin therapy, which reduces elevated lipoproteins in hypercholesterolaemic men, may lower risks of CHD and mortality partly by lowering plasma and blood viscosity. Further studies are required to test this hypothesis

Field analysis of groundwater for volatile organic contaminants using on-column aqueous injection capillary gas chromatography

Northeast Utilities Service Company, Southern California Edison Company, Empire State Electric Energy Research Corporation, American Power Service Company, Standard Oil Company and New England Power Service Company under the MIT Energy Laboratory Utilites Progra

Are hygiene standards useful in assessing infection risk?

We monitored the surface level cleanliness of a five-bedded surgical intensive care unit (SICU) over a ten-week period in order to evaluate proposed hygiene standards.Ten environmental sites within SICU were sampled twice weekly along with collection of clinical and patient activity data. The standards designate aerobic colony counts (ACCs) >2.5cfu/cm2 from hand-touch sites and the presence of Staphylococcus aureus as hygiene failures. Nearly a quarter of 200 samples failed the standards, mostly from hand-touch sites on curtains, beds and medical equipment. The total number of fails each week was associated with bed occupancy (p=0.04), trending towards association with SICU-acquired infections (p=0.11). Environmental S.aureus was associated with the proportion of beds occupied (p = 0.02). Indistinguishable genotypes were found between patient and environmental staphylococci, with timescales supporting staphylococcal transmission in both directions. Hygiene standards based on microbial growth levels and the presence of S.aureus reflect patient activity and provide a means to risk manage infection. They also exposed a staphylococcal reservoir that could represent a more tangible risk to patients. Standards for surface level cleanliness deserve further evaluation

Mobilization of colloids in groundwater due to infiltration of water at a coal ash disposal site

We investigated groundwaters in the vicinity of a coal ash site near an electric generating station in the western U.S.A. The purpose of the study was to ascertain why fine particles or colloids appear in some subsurface water samples there. If such fine particles are merely introduced during bailing or pumping operations which suspend otherwise immobile soil colloids, we should exclude these particulate materials from the water samples before analysis intended to quantify what is moving through the aquifer. However, if the colloids were truly suspended and moving with the groundwater flow in situ, then we should include their contribution to our assessment of the mobile loads. Application of very careful sampling techniques (slow pumping rates, no atmospheric exposure) did not cause the large quantities of colloids observed previously to disappear from well water in which they occurred. Additionally, the same sampling procedures did not cause similar abun- dances of colloids to appear in waters collected from neighboring wells installed and' developed in the same manner and in the same geologic strata. Thus we believe sampling artifacts do not explain the colloids' presence in the groundwater samples. On the other hand, the groundwater chemistry and the nature of the suspended colloids (size, composition) strongly suggest these fine particles were suspended and therefore moving with the groundwater flow. At wells exhibiting large amounts of suspended colloids (- 10-100mg L-), the water was enriched in CO2 and depleted in 02 relative to nearby locations. The colloids were typically between 0.1 and 2 gm in size and were primarily silicates. These results suggest to us that, where infiltrating water is percolating through a site that has been mixed with coal ash, the secondary carbonate minerals in the soils are being dissolved; removal of this cementing carbonate phase may consequently release soil silicate colloids to be carried in the flowing water. Such processes may enhance contaminant transport in groundwater by augmenting the pollutant load moving in the groundwater, and increasing the permeability of the porous medium to pollutant infiltration with waste water and/or rainwater