1,953 research outputs found
Time and dose dependency of bone-sarcomas in patients injected with radium-224
The time course and dose dependency of the incidence of bone-sarcomas among 900 German patients treated with high doses of radium-224 is analysed in terms of a proportional hazards model with a log-normal dependency of time to tumor and a linear-quadratic dose relation. The deduced dose dependency agrees well with a previous analysis in terms of a non-parametric proportional hazards model, and confirms the temporal distribution which has been used in the Radioepidemiological Tables of NIH. However, the linear-quadratic dose-response model gives a risk estimate for low doses which is somewhat less than half that obtained under the assumption of linearity.
Dedicated to Prof. W. Jacobi on the occasion of his 60th birthday
Work performed under Euratom contracts BI6-D-083-D, BI6-F-111-D, U.S. Department of Energy contract DE-AC 02-76 EV-00119, the U.S. National Cancer Institut
The organisational and human resource challenges facing primary care trusts : protocol of a multiple case study
BACKGROUND: The study is designed to assess the organisational and human resource challenges faced by Primary Care Trusts (PCTs). Its objectives are to: specify the organisational and human resources challenges faced by PCTs in fulfilling the roles envisaged in government and local policy; examine how PCTs are addressing these challenges, in particular, to describe the organisational forms they have adopted, and the OD/HR strategies and initiatives they have planned or in place; assess how effective these structures, strategies and initiatives have been in enabling the PCTs to meet the organisational and human resources challenges they face; identify the factors, both internal to the PCT and in the wider health community, which have contributed to the success or failure of different structures, strategies and initiatives. METHODS: The study will be undertaken in three stages. In Stage 1 the key literature on public sector and NHS organisational development and human resources management will be reviewed, and discussions will be held with key researchers and policy makers working in this area. Stage 2 will focus on detailed case studies in six PCTs designed to examine the organisational and human resources challenges they face. Data will be collected using semi-structured interviews, group discussion, site visits, observation of key meetings and examination of local documentation. The findings from the case study PCTs will be cross checked with a Reference Group of up to 20 other PCG/Ts, and key officers working in organisational development or primary care at local, regional and national level. In Stage 3 analysis of findings from the preparatory work, the case studies and the feedback from the Reference Group will be used to identify practical lessons for PCTs, key messages for policy makers, and contributions to further theoretical development
The Reverse Protraction Factor in the Induction of Bone Sarcomas in Radium-224 Patients
Verification of real-time WSA-ENLIL+Cone simulations of CME arrival-time at the CCMC from 2010-2016
The Wang-Sheeley-Arge (WSA)-ENLIL+Cone model is used extensively in space
weather operations world-wide to model CME propagation. As such, it is
important to assess its performance. We present validation results of the
WSA-ENLIL+Cone model installed at the Community Coordinated Modeling Center
(CCMC) and executed in real-time by the CCMC space weather team. CCMC uses the
WSA-ENLIL+Cone model to predict CME arrivals at NASA missions throughout the
inner heliosphere. In this work we compare model predicted CME arrival-times to
in-situ ICME leading edge measurements at STEREO-A, STEREO-B, and Earth (Wind
and ACE) for simulations completed between March 2010-December 2016 (over 1,800
CMEs). We report hit, miss, false alarm, and correct rejection statistics for
all three locations. For all predicted CME arrivals, the hit rate is 0.5, and
the false alarm rate is 0.1. For the 273 events where the CME was predicted to
arrive at Earth, STEREO-A, or STEREO-B, and was actually observed (hit event),
the mean absolute arrival-time prediction error was 10.4 +/- 0.9 hours, with a
tendency to early prediction error of -4.0 hours. We show the dependence of the
arrival-time error on CME input parameters. We also explore the impact of the
multi-spacecraft observations used to initialize the model CME inputs by
comparing model verification results before and after the STEREO-B
communication loss (since September 2014) and STEREO-A sidelobe operations
(August 2014-December 2015). There is an increase of 1.7 hours in the CME
arrival time error during single, or limited two-viewpoint periods, compared to
the three-spacecraft viewpoint period. This trend would apply to a future space
weather mission at L5 or L4 as another coronagraph viewpoint to reduce CME
arrival time errors compared to a single L1 viewpoint
Scoping studies: towards a methodological framework
This paper focuses on scoping studies, an approach to reviewing the literature which to date has received little attention in the research methods literature. We distinguish between different types of scoping studies and indicate where these stand in relation to full systematic reviews. We outline a framework for conducting a scoping study based on our recent experiences of reviewing the literature on services for carers for people with mental health problems. Where appropriate, our approach to scoping the field is contrasted with the procedures followed in systematic reviews. We emphasize how including a consultation exercise in this sort of study may enhance the results, making them more useful to policy makers, practitioners and service users. Finally, we consider the advantages and limitations of the approach and suggest that a wider debate is called for about the role of the scoping study in relation to other types of literature reviews
Use of Drawings to Explore US Women's Perspectives on Why People Might Decline HIV Testing
The purpose of this research is to explore through drawings and verbal descriptions women's perspectives about reasons why persons might decline human immunodeficiency virus (HIV) testing. We asked 30 participants to draw a person that would NOT get tested for HIV and then explain drawings. Using qualitative content analysis, we extracted seven themes. We found apprehension about knowing the result of an HIV test to be the most commonly identified theme in women's explanations of those who would not get tested. This technique was well received and its use is extended to HIV issues
Using XML and XSLT for flexible elicitation of mental-health risk knowledge
Current tools for assessing risks associated with mental-health problems require assessors to make high-level judgements based on clinical experience. This paper describes how new technologies can enhance qualitative research methods to identify lower-level cues underlying these judgements, which can be collected by people without a specialist mental-health background.
Methods and evolving results: Content analysis of interviews with 46 multidisciplinary mental-health experts exposed the cues and their interrelationships, which were represented by a mind map using software that stores maps as XML. All 46 mind maps were integrated into a single XML knowledge structure and analysed by a Lisp program to generate quantitative information about the numbers of experts associated with each part of it. The knowledge was refined by the experts, using software developed in Flash to record their collective views within the XML itself. These views specified how the XML should be transformed by XSLT, a technology for rendering XML, which resulted in a validated hierarchical knowledge structure associating patient cues with risks.
Conclusions: Changing knowledge elicitation requirements were accommodated by flexible transformations of XML data using XSLT, which also facilitated generation of multiple data-gathering tools suiting different assessment circumstances and levels of mental-health knowledge
LOSS OF PHOSPHORUS BY RUNOFF FOR AGRICULTURAL WATERSHEDS
The loss of nutrients in runoff from agricultural land is a major cause of poor surface water quality in the United State. Scientists (NRCS) developed a technique to estimate the impact of agricultural watersheds on natural water resources. The objectives of this study were to apply this technique on the Wagon Train (WT),watershed to predict (1) loss of water by surface runoff, (2) loss of phosphorus (P) from soils by runoff and P loading for WT reservoir. The annual loss of water by runoff was estimated at 4.32 million m3 . The USGS data for a 50-year period (1951 to 2000) indicated that the average annual inflow for WT reservoir was 4.25 million m3 . The predicted annual P loss by runoff was 844 kg and could be considered as the annual loading for WT reservoir. The predicted P concentration in the runoff water at field sites was 196 μg/L. Phosphorus concentration observed in major streams at the beginning of spring (March) ranged from 99 μg/L to 240 μg/L with an average of 162 μg/L (S.D..= 40 μg/L), and the average P concentration in water samples taken from different locations in the reservoir was 140 μg/L. Phosphorus uptake by algae, weeds and aquatic plants, as well as high pH in the reservoir and streams might explain the slight drop of P concentration in waters. Further, the average P concentration observed in the main stream samples for the entire rainy season (March through October), ranged between 157 and 346 μg/L with an average of 267 μg/L (S.D. = 65 μg/L). Application of P fertilizers (April/May) for summer crops might explain the increase in P concentration. When factors affecting P concentration in streams are considered, the technique could provide a reasonable estimation of P concentration in stream water
- …