734 research outputs found
Analyses of the dynamic docking test system for advanced mission docking system test programs
Results are given of analytical studies performed in support of the design, implementation, checkout and use of NASA's dynamic docking test system (DDTS). Included are analyses of simulator components, a list of detailed operational test procedures, a summary of simulator performance, and an analysis and comparison of docking dynamics and loads obtained by test and analysis
Does a monetary incentive improve the response to a postal questionnaire in a randomised controlled trial? : the MINT incentive study
Background: Sending a monetary incentive with postal questionnaires has been found to improve
the proportion of responders, in research in non-healthcare settings. However, there is little
research on use of incentives to improve follow-up rates in clinical trials, and existing studies are
inconclusive. We conducted a randomised trial among participants in the Managing Injuries of the
Neck Trial (MINT) to investigate the effects on the proportion of questionnaires returned and
overall non-response of sending a £5 gift voucher with a follow-up questionnaire.
Methods: Participants in MINT were randomised to receive either: (a) a £5 gift voucher (incentive
group) or (b) no gift voucher (no incentive group), with their 4 month or 8 month follow-up
questionnaire. We recorded, for each group, the number of questionnaires returned, the number
returned without any chasing from the study office, the overall number of non-responders (after
all chasing efforts by the study office), and the costs of following up each group.
Results: 2144 participants were randomised, 1070 to the incentive group and 1074 to the no
incentive group. The proportion of questionnaires returned (RR 1.10 (95% CI 1.05, 1.16)) and the
proportion returned without chasing (RR 1.14 (95% CI 1.05, 1.24) were higher in the incentive
group, and the overall non-response rate was lower (RR 0.68 (95% CI 0.53, 0.87)). Adjustment for
injury severity and hospital of recruitment to MINT made no difference to these results, and there
were no differences in results between the 4-month and 8-month follow up questionnaires.
Analysis of costs suggested a cost of £67.29 per additional questionnaire returned.
Conclusion: Monetary incentives may be an effective way to increase the proportion of postal
questionnaires returned and minimise loss to follow-up in clinical trials
A national survey of clinical practice for the management of whiplash-associated disorders in UK emergency departments
Objective: To undertake a national survey to determine current practice for the management of whiplash injuries in UK emergency departments (ED).
Methods: Postal questionnaire survey. 316 lead consultants from all UK ED with annual new attendances of over 50 000 people were asked to indicate the use of a range of treatments and the frequency with which these treatments were used. Samples of written advice were requested and content analysis was conducted and compared with survey responses.
Results: The response rate was 79% (251/316). The intervention most frequently used was verbal advice to exercise, reported by 84% of respondents for most or all cases, and advice against the use of a collar (83%). Other treatments reported as being used frequently were written advice and anti-inflammatory medication. 106 consultants (42%) provided a sample of written materials. Reference to expected recovery and encouragement for early return to activities were included in less than 6%. Nearly 50% of written materials contained information on how to use a soft collar and 61% contained information on solicitors and pursuing a personal injury claim. There were important differences between reported verbal behaviours and written advice.
Conclusion: Verbal advice is the primary method for managing whiplash injuries in ED and is usually supplemented by written advice. Within individual hospitals there is a lack of consistency between verbal and written advice. The promotion of personal injury claims is a common feature of written advice. Research is required to develop effective and consistent models of advice
A Detailed Model Atmosphere Analysis of Cool White Dwarfs in the Sloan Digital Sky Survey
We present optical spectroscopy and near-infrared photometry of 126 cool
white dwarfs in the Sloan Digital Sky Survey (SDSS). Our sample includes high
proper motion targets selected using the SDSS and USNO-B astrometry and a dozen
previously known ultracool white dwarf candidates. Our optical spectroscopic
observations demonstrate that a clean selection of large samples of cool white
dwarfs in the SDSS (and the SkyMapper, Pan-STARRS, and the Large Synoptic
Survey Telescope datasets) is possible using a reduced proper motion diagram
and a tangential velocity cut-off (depending on the proper motion accuracy) of
30 km/s. Our near-infrared observations reveal eight new stars with significant
absorption. We use the optical and near-infrared photometry to perform a
detailed model atmosphere analysis. More than 80% of the stars in our sample
are consistent with either pure hydrogen or pure helium atmospheres. However,
the eight stars with significant infrared absorption and the majority of the
previously known ultracool white dwarf candidates are best explained with mixed
hydrogen and helium atmosphere models. The age distribution of our sample is
consistent with a Galactic disk age of 8 Gyr. A few ultracool white dwarfs may
be as old as 12-13 Gyr, but our models have problems matching the spectral
energy distributions of these objects. There are only two halo white dwarf
candidates in our sample. However, trigonometric parallax observations are
required for accurate mass and age determinations and to confirm their
membership in the halo.Comment: ApJ Supplements, in pres
Is diversity good?
Prominent ethical and policy issues such as affirmative action and female
enrollment in science and engineering revolve around the idea that diversity is
good. However, even though diversity is an ambiguous concept, a precise
definition is seldom provided. We show that diversity may be construed as a
factual description, a craving for symmetry, an intrinsic good, an instrumental
good, a symptom, or a side effect. These acceptions differ vastly in their
nature and properties. The first one cannot lead to any action and the second
one is mistaken. Diversity as intrinsic good is a mere opinion, which cannot be
concretely applied; moreover, the most commonly invoked forms of diversity
(sexual and racial) are not intrinsically good. On the other hand, diversity as
instrumental good can be evaluated empirically and can give rise to policies,
but these may be very weak. Finally, symptoms and side effects are not actually
about diversity. We consider the example of female enrollment in science and
engineering, interpreting the various arguments found in the literature in
light of this polysemy.
Keywords: ethics, policy, higher education, female students, minority
students, affirmative actionComment: 7 page
An Evaluation of Agreement of Breathing Rates Measured by a Novel Device, Manual Counting, and Other Techniques Used in Clinical Practice: Protocol for the Observational VENTILATE Study.
BACKGROUND: Respiratory rate (RR) is the most sensitive physiological observation to predict clinical deterioration on hospital wards, and poor clinical monitoring has been highlighted as a primary contributor to avoidable mortality. Patients in intensive care have their RR monitored continuously, but this equipment is rarely available on general hospital wards. OBJECTIVE: The primary objective is to assess the accuracy of the RespiraSense device in comparison with other methods currently used in clinical practice. The secondary objective is to assess the accuracy of the RespiraSense device in participants in different positions and when reading aloud. METHODS: A single-center, prospective observational study will investigate the agreement of the RespiraSense device as compared with other device measurements (capnography, electrocardiogram) and the current standard measurement of RR (manual counting by a trained health care professional). The different methods will be employed concurrently on the same participant as part of a single study visit. RESULTS: Recruitment to this study has not yet started as funding decisions are still pending. Therefore, results are not available at this stage. It is anticipated that the data required could be collected within 2 months of first recruitment to the study and data analysis completed within 6 months of the study start date. CONCLUSIONS: The Evaluation of Agreement of Breathing Rates Measured by a Novel Device, Manual Counting, and Other Techniques Used in Clinical Practice (VENTILATE) study will provide further validation of the use of the RespiraSense device in subjects with abnormal respiratory rates. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/15437
The Lick AGN Monitoring Project 2011: Dynamical Modeling of the Broad-Line Region
We present models of the H-emitting broad-line region (BLR) in seven
Seyfert 1 galaxies from the Lick AGN (Active Galactic Nucleus) Monitoring
Project 2011 sample, drawing inferences on the BLR structure and dynamics as
well as the mass of the central supermassive black hole. We find that the BLR
is generally a thick disk, viewed close to face-on, with preferential emission
back toward the ionizing source. The dynamics in our sample range from
near-circular elliptical orbits to inflowing or outflowing trajectories. We
measure black hole masses of for PG 1310108, for Mrk 50,
for Mrk 141, for Mrk 279,
for Mrk 1511, for NGC 4593, and
for Zw 229015. We use these black hole mass
measurements along with cross-correlation time lags and line widths to recover
the scale factor used in traditional reverberation mapping measurements.
Combining our results with other studies that use this modeling technique,
bringing our sample size to 16, we calculate a scale factor that can be used
for measuring black hole masses in other reverberation mapping campaigns. When
using the root-mean-square (rms) spectrum and using the line dispersion to
measure the line width, we find . Finally, we search for correlations between and other AGN
and BLR parameters and find marginal evidence that is correlated with
and the BLR inclination angle, but no significant evidence of a
correlation with the AGN luminosity or Eddington ratio.Comment: 26 pages, 14 figures. Accepted for publication in Ap
Managing Injuries of the Neck Trial (MINT) : design of a randomised controlled trial of treatments for whiplash associated disorders
Background: A substantial proportion of patients with whiplash injuries develop chronic
symptoms. However, the best treatment of acute injuries to prevent long-term problems is
uncertain. A stepped care treatment pathway has been proposed, in which patients are given advice
and education at their initial visit to the emergency department (ED), followed by review at three
weeks and physiotherapy for those with persisting symptoms. MINT is a two-stage randomised
controlled trial to evaluate two components of such a pathway: 1. use of The Whiplash Book versus
usual advice when patients first attend the emergency department; 2. referral to physiotherapy
versus reinforcement of advice for patients with continuing symptoms at three weeks.
Methods: Evaluation of the Whiplash Book versus usual advice uses a cluster randomised design
in emergency departments of eight NHS Trusts. Eligible patients are identified by clinicians in
participating emergency departments and are sent a study questionnaire within a week of their ED
attendance. Three thousand participants will be included. Patients with persisting symptoms three
weeks after their ED attendance are eligible to join an individually randomised study of
physiotherapy versus reinforcement of the advice given in ED. Six hundred participants will be
randomised. Follow-up is at 4, 8 and 12 months after their ED attendance. Primary outcome is the
Neck Disability Index (NDI), and secondary outcomes include quality of life and time to return to
work and normal activities. An economic evaluation is being carried out.
Conclusion: This paper describes the protocol and operational aspects of a complex intervention
trial based in NHS emergency and physiotherapy departments, evaluating two components of a
stepped-care approach to the treatment of whiplash injuries. The trial uses two randomisations,
with the first stage being cluster randomised and the second individually randomised
The observation and simulation of diurnal surface thermal contrast in an Alaskan alpine pass
A simple surface climate simulator was employed in the analysis of thermal regimes in rough alpine terrain at Chitistone Pass, Alaska. The simulator favorably abstracts observations of thermal regimes on flat and sloping surfaces with variable thermal and radiative properties. It is shown that slope and exposure control variations in surface thermal regimes. The simulator predicts these controls and it is suggested that simulation of surface thermal regimes can be performed before and after field investigations, thus increasing the effective information content of thermal maps acquired using aircraft and orbital platforms. It is concluded that the removal by spatial filtering of the low frequency effects of slope and exposure on thermal maps is necessary before site material effects can be discriminated and analyzed. Ein einfaches Rechenmodell des Bodenklimas wurde auf die Analyse des Temperaturregimes im unebenen Terrain des Chitistone-Passes in Alaska angewandt. Das Modell bildet die beobachteten Temperaturregime ebener und geneigter Bodenflächen mit veränderlichen Wärmeleit- und Strahlungscharakteristiken zufriedenstellend ab. Es wird gezeigt, daß Hangneigung und Hanglage im wesentlichen das Bodentemperaturregime bedingen. Das Modell sagt diese Bedingungsfaktoren richtig voraus. Es wird daher vorgeschlagen, daß Modellrechnungen vor und nach Feldmessungen angestellt werden sollten, um den effektiven Informationsgehalt der Temperaturverteilungskarten zu erhöhen, die von Flugzeugen oder Satelliten vermessen wurden. Es wird darauf hingewiesen, daß die Unterdrückung niederfrequenter Effekte von Hangneigung und Hanglage auf die kartographisch festgehaltene Temperaturverteilung notwendig ist, bevor Bodenbeschaffenheitseffekte diskriminiert und analysiert werden können. Diese Unterdrückung kann durch räumliche Filterung geschehen.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41669/1/704_2005_Article_BF02243725.pd
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