299 research outputs found
Microstructural characterisation of TiAlTiAu and TiAlPdAu ohmic contacts to AlGaN/GaN
Ti/Al/Ti/Au and Ti/Al/Pd/Au contacts to AlGaN/GaN have been investigated to ascertain the effect of annealing temperature on the structural evolution of the contacts. Ti/Al/Ti/Au contacts become ohmic after rapid thermal annealing at 750°C or higher, corresponding to the formation of an interfacial TiN phase, with inclusions penetrating through the AlGaN layer observed after annealing at 950°C. The Pd layer is shown to be more efficient at inhibiting diffusion of Au to the interface than Ti. Ohmic behaviour was not seen with the Ti/Al/Pd/Au scheme. Either the presence of Au at the interface may improve ohmic behaviour, or the Ti:Al ratio is insufficient in this scheme
Microstructural characterisation of TiAlTiAu and TiAlPdAu ohmic contacts to AlGaN/GaN
Ti/Al/Ti/Au and Ti/Al/Pd/Au contacts to AlGaN/GaN have been investigated to ascertain the effect of annealing temperature on the structural evolution of the contacts. Ti/Al/Ti/Au contacts become ohmic after rapid thermal annealing at 750°C or higher, corresponding to the formation of an interfacial TiN phase, with inclusions penetrating through the AlGaN layer observed after annealing at 950°C. The Pd layer is shown to be more efficient at inhibiting diffusion of Au to the interface than Ti. Ohmic behaviour was not seen with the Ti/Al/Pd/Au scheme. Either the presence of Au at the interface may improve ohmic behaviour, or the Ti:Al ratio is insufficient in this scheme
Supervised machine learning algorithms can classify open-text feedback of doctor performance with human-level accuracy
Background: Machine learning techniques may be an effective and efficient way to classify open-text reports on doctorâs activity for the purposes of quality assurance, safety, and continuing professional development. Objective: The objective of the study was to evaluate the accuracy of machine learning algorithms trained to classify open-text reports of doctor performance and to assess the potential for classifications to identify significant differences in doctorsâ professional performance in the United Kingdom. Methods: We used 1636 open-text comments (34,283 words) relating to the performance of 548 doctors collected from a survey of cliniciansâ colleagues using the General Medical Council Colleague Questionnaire (GMC-CQ). We coded 77.75% (1272/1636) of the comments into 5 global themes (innovation, interpersonal skills, popularity, professionalism, and respect) using a qualitative framework. We trained 8 machine learning algorithms to classify comments and assessed their performance using several training samples. We evaluated doctor performance using the GMC-CQ and compared scores between doctors with different classifications using t tests. Results: Individual algorithm performance was high (range F score=.68 to .83). Interrater agreement between the algorithms and the human coder was highest for codes relating to âpopularâ (recall=.97), âinnovatorâ (recall=.98), and ârespectedâ (recall=.87) codes and was lower for the âinterpersonalâ (recall=.80) and âprofessionalâ (recall=.82) codes. A 10-fold cross-validation demonstrated similar performance in each analysis. When combined together into an ensemble of multiple algorithms, mean human-computer interrater agreement was .88. Comments that were classified as ârespected,â âprofessional,â and âinterpersonalâ related to higher doctor scores on the GMC-CQ compared with comments that were not classified (P.05). Conclusions: Machine learning algorithms can classify open-text feedback of doctor performance into multiple themes derived by human raters with high performance. Colleague open-text comments that signal respect, professionalism, and being interpersonal may be key indicators of doctorâs performance
The Global Campaign turns 18: a brief review of its activities and achievements
The Global Campaign against Headache, as a collaborative activity with the World Health Organization (WHO), was formally launched in Copenhagen in March 2004. In the month it turns 18, we review its activities and achievements, from initial determination of its strategic objectives, through partnerships and project management, knowledge acquisition and awareness generation, to evidence-based proposals for change justified by cost-effectiveness analysis
Ambient BTEX exposure and mid-pregnancy inflammatory biomarkers in pregnant African American women
Air pollution is associated with preterm birth (PTB), potentially via inflammation. We recently showed the mixture benzene, toluene, ethylbenzene, and xylene (BTEX) is associated with PTB. We examined if ambient BTEX exposure is associated with mid-pregnancy inflammation in a sample of 140 African-American women residing in Detroit, Michigan. The Geospatial Determinants of Health Outcomes Consortium study collected outdoor air pollution measurements in Detroit; these data were coupled with Michigan Air Sampling Network measurements to develop monthly BTEX concentration estimates at a spatial density of 300âm(2). First trimester and mid-pregnancy BTEX exposure estimates were assigned to maternal address. Mid-pregnancy (mean 21.3â±â3.7 weeks gestation) inflammatory biomarkers (high-sensitivity C-reactive protein, interleukin [IL]-6, IL-10, IL-1ÎČ, and tumor necrosis factor-α) were measured with enzyme immunoassays. After covariate adjustment, for every 1-unit increase in first trimester BTEX, there was an expected mean increase in log-transformed IL-1ÎČ of 0.05â±â0.02 units (Pâ=â0.014) and an expected mean increase in log-transformed tumor necrosis factor-α of 0.07â±â0.02 units (Pâ=â0.006). Similarly, for every 1-unit increase in mid-pregnancy BTEX, there was a mean increase in log IL-1ÎČ of 0.06â±â0.03 units (Pâ=â0.027). There was no association of either first trimester or mid-pregnancy BTEX with high-sensitivity C-reactive protein, IL-10, or IL-6 (all Pâ\u3eâ0.05). Ambient BTEX exposure is associated with inflammation in mid-pregnancy in African-American women. Future studies examining if inflammation mediates associations between BTEX exposure and PTB are needed
âWhy havenât I got one of those?â A consideration regarding the need to protect non-participant children in early years research
It is widely documented that young children participating in research should be protected from harm and that ethical considerations should be applied throughout a research project. What this paper strives to assert, however, is that protecting these participants is insufficient. A research project into childrenâs speech and language development, using audioâ-visual methods, highlighted that children who are non-participants, those on the periphery of research, can also be affected by the research process. It is acknowledged throughout this paper that although ethical procedures were adhered to whilst undertaking a specific research project, this was insufficient. It is therefore argued that all children within a research environment, whether participatory or not, should be given equal consideration with regards to ethical protection when undertaking research. It is asserted that ââwhy havenât I got one of thoseââ, or the equivalent, is a phrase to be avoided at all costs when undertaking research with children
The impact of the CalmanâHine report on the processes and outcomes of care for Yorkshire's colorectal cancer patients
The 1995 CalmanâHine plan outlined radical reform of the UK's cancer services with the aim of improving outcomes and reducing inequalities in NHS cancer care. Its main recommendation was to concentrate care into the hands of site-specialist, multi-disciplinary teams. This study aimed to determine if the implementation of CalmanâHine cancer teams was associated with improved processes and outcomes of care for colorectal cancer patients. The design included longitudinal survey of 13 colorectal cancer teams in Yorkshire and retrospective study of population-based data collected by the Northern and Yorkshire Cancer Registry and Information Service. The population was all colorectal cancer patients diagnosed and treated in Yorkshire between 1995 and 2000. The main outcome measures were: variations in the use of anterior resection and preoperative radiotherapy in rectal cancer, chemotherapy in Dukes stage C and D patients, and five-year survival. Using multilevel models, these outcomes were assessed in relation to measures of the extent of CalmanâHine implementation throughout the study period, namely: (i) each team's degree of adherence to the Manual of Cancer Service Standards (which outlines the specification of the âidealâ colorectal cancer team) and (ii) the extent of site specialisation of each team's surgeons. Variation was observed in the extent to which the colorectal cancer teams in Yorkshire had conformed to the CalmanâHine recommendations. An increase in surgical site specialisation was associated with increased use of preoperative radiotherapy (OR=1.43, 95% CI=1.04â1.98, P<0.04) and anterior resection (OR=1.43, 95% CI=1.16â1.76, P<0.01) in rectal cancer patients. Increases in adherence to the Manual of Cancer Service Standards was associated with improved five-year survival after adjustment for the casemix factors of age, stage of disease, socioeconomic status and year of diagnosis, especially for colon cancer (HR=0.97, 95% CI=0.94â0.99 P<0.01). There was a similar trend of improved survival in relation to increased surgical site specialisation for rectal cancer, although the effect was not statistically significant (HR=0.93, 95% CI=0.84â1.03, P=0.15). In conclusion, the extent of implementation of the CalmanâHine report has been variable and its recommendations are associated with improvements in processes and outcomes of care for colorectal cancer patients
The Role of Hospitalists in the Acute Care of Stroke Patients
Stroke care has become progressively more complicated with advances in therapies necessitating timely intervention. There are multiple potential providers of stroke care, which traditionally has been the province of general neurologists and primary care physicians. These new players, be they vascular neurologists, neurohospitalists, internal medicine hospitalists, or neurocritical care physicians, at the bedside or at a distance, are poised to make a significant impact on our care of stroke patients. The collaborative model of care may be or become the most prevalent as physicians apply their distinct skill sets to the complex care of inpatients with cerebrovascular disease
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