Field statistics in an enclosure with an aperture: Effect of Q-factor and Number of Modes

The statistics of the fields within an enclosure illuminated by an external field via an aperture have been investigated using Monte-Carlo methods. The field statistics in the volume of the enclosure are shown to correspond to the Rayleigh statistics found in properly functioning reverberation chambers when a sufficiently large number of modes is excited. The variation of field behaviour near the conducting walls is investigated. The deviation of the field statistics from the Rayleigh distribution as the number of excited modes falls is also investigated

The relationship between hiv duration, insulin resistance and diabetes risk

The risk of developing Type 2 Diabetes Mellitus in people living with HIV (PLWH) can be four times greater and can occur at an earlier age and even without the presence of obesity compared to those without HIV. Therefore, the purpose of this analytical cross-sectional study was to determine the relationship between HIV duration and glucose metabolism among PLWH. Eighty-two PLWH were categorized into shorter (≤15 years) or longer HIV duration (≥16 years) and then compared for differences in demographics, physical and clinical characteristics, biomarkers, and dietary intake. Compared to those with shorter HIV duration (n = 34), those with longer HIV duration (n = 48) were on average older (p = 0.02), reported lower consumption of alcohol (p = 0.05), had higher levels of homeostasis model assessment of insulin resistance (HOMA-IR, p = 0.02), were also more likely to be a woman (p = 0.06), and have higher levels of fasting insulin (p = 0.06). When adjusted for age and body weight, the levels of HOMA-IR and fasting insulin were higher (p = 0.02 and p = 0.04) with longer compared to shorter HIV duration, respectively. Longer exposure to HIV infection is associated with impaired insulin sensitivity. Continuing research aimed at the long-term effects of HIV infection and (antiretroviral therapy) is required

Computational electromagnetic (CEM) model validation against measured and calculated results

The paper presents examples of the validation of numerical models using measured and calculated results from a range of research projects undertaken at York. These aim to show that both the measurement and computational model are approximate representations of the real-world, and that significant effort must be made to ensure that they are sufficiently similar if useful results and validation are to be obtained. We shall also discuss how the choice of metrics for the comparison of numerical, analytical and measured data is influenced by the nature of the EM problem being investigate

The use of reverberation chambers in the quantitative assessment of the risk associated with the installation of electronic systems on vehicles.

The EU SAFETEL Project was concerned with the safety implications of installing electronic equipment on vehicles. Part of the project concerned the development of a risk assessment model suitable for predicting an upper bound on the probability of failure of an electronic system installed inside a vehicle that is irradiated externally or internally. Only limited information on the immunity of the device and associated cabling is required. As an example, the model is used to demonstrate the probability of failure of a system due to irradiation from Digital Audio Broadcast (DAB) transmitters in the United Kingdom (UK). The failure probability is found to be highly sensitive to the clearance above the vehicle chassis of wire looms attached to the system, and to the accuracy with which the electric field is measured during an immunity test for the system/cable combination. The failure probability predicted by the risk assessment model is consistent with common observations of a log-normal distribution in the terminating power of receiving cables inside an irradiated vehicle confirmed by measurements in a reverberation chamber. In this paper we describe the experiments undertaken in the reverberation chamber and present the results of the experiments which illustrate their correspondence with the theoretical and observed statistics of the power received by cable terminations in a lossy enclosed space such as a vehicle. The rotational positions of the stirrer substitute for the statistical nature of the excitation fields in the vehicle and the variations of positioning of the cables within the vehicle. An example system comprising a multisensor ultrasonic parking warning system was used in the experiments and good agreement was achieved between the predictions and the observed failures of the system when under test. This paper is illustrates the potential for the use of reverberation chambers for testing systems that may be installed on vehicles and integrating the test results with a quantitative risk assessment of the vehicle operated in a real environment

Efficient simulations for automotive design

Some preliminary results are presented for the statistical coupling of EM radiation to a transmission line inside a lossy chamber with an aperture. The rapid Intermediate Level Circuit Modelling (ILCM) technique has been used to obtain the results, which have relevance to the calculation of the probability of failure of a vehicle subsystem in situ

Randomized controlled trial comparing four strategies for delivering e-curriculum to health care professionals [ISRCTN88148532]

BACKGROUND: Internet education is increasingly provided to health professionals, but little is known about the most effective strategies for delivering the content. The purpose of this study is to compare four strategies for delivering an Internet-based (e-) curriculum on clinicians' knowledge (K), confidence (CONF), and communication (COMM) about herbs and other dietary supplements (HDS). METHODS: This national randomized 2 × 2 factorial trial included physicians, pharmacists, nurses, nutritionists and trainees in these fields. Participants were randomly assigned to one of four curriculum delivery strategies for 40 brief modules about HDS: a) delivering four (4) modules weekly over ten (10) weeks by email (drip-push); b) modules accessible on web site with 4 reminders weekly for 10 weeks (drip-pull); c) 40 modules delivered within 4 days by email (bolus-push); and d) 40 modules available on the Internet with one email informing participants of availability (bolus-pull). RESULTS: Of the 1,267 enrollees, 25% were male; the average age was 40 years. The completion rate was 62%, without significant differences between delivery groups. There were statistically significant improvements in K, CONF and COMM scores after the course (P<0.001 for all), although the difference in COMM was small. There were no significant differences in any of the three outcomes by delivery strategy, but outcomes were better for those who paid for continuing education credit. CONCLUSION: All delivery strategies tested similarly improved K, CONF, COMM scores about HDS. Educators can use the strategy that is most convenient without diminishing effectiveness. Additional curricula may be necessary to make substantial changes in clinicians' communication practices

Electromagnetic coupling to an enclosure via a wire penetration

Abstract: The paper presents results which demonstrate that radiated emissions from heatsinks are reduced by an amount that depends upon the distribution and impedance of the grounding structure. Results are also presented which show the effect on radiated emissions of the presence of conductors (e.g. PCB tracks) passing under the heatsink. The presence of conductors reduces the effectiveness of the heatsink grounding but, in most case, emissions at high frequencies do not exceed those without conductors attached

Knowledge and exposure to complementary and alternative medicine in paediatric doctors: a questionnaire survey

<p>Abstract</p> <p>Background</p> <p>Complementary and alternative medicines are increasingly used by the general population. A survey was conducted to ascertain the knowledge of Complementary and Alternative Medicines (CAMs) amongst paediatric physicians, and whether seniority increases the likelihood of its use being considered in consultations, or of families discussing it.</p> <p>Methods</p> <p>Anonymous survey of general paediatric doctors in a large inner-city district general hospital (DGH) and tertiary children's centre (TC) using a questionnaire. Statistical analysis was calculated using Minitab.</p> <p>Results</p> <p>43/49 (88%) questionnaires were returned correctly. 13 (30%, CI 17 – 46%) doctors had personally used CAMs. 24 (56%, CI 40 – 71%) of their families had used CAMs. 13 (30%, CI 17 – 46%) had received formal CAMs education. 21 (49%, CI 40 – 71%) could name a total of 5 types of CAMs. Consultants were significantly more likely to ask about CAM use than middle-grades and juniors (p < 0.05, CI 48 – 93%, 35 – 90%, 8 – 33% respectively) and have had a clinical encounter where they felt it was significant. 32 (74%, CI 59 – 86%) of the clinicians had been asked about CAMs. 33 (77%, CI 61 – 88%) of doctors had successful CAM use reported to them, and 20 (47%, CI 31 – 62%) had failure of CAMs reported to them.</p> <p>Conclusion</p> <p>CAM use is relatively common in paediatric doctors and their families. They have received little formal CAMs education. Consultants were more likely than juniors to ask about CAM use and have had a clinical encounter where it played a significant part. Around half of all doctors irrespective of grade have been asked about CAMs in a clinical encounter.</p

FRUITFLYRISKMANAGE: A Euphresco project for Ceratitis capitata Wiedemann (Diptera: Tephritidae) risk management applied in some European countries

Ceratitis capitata (Wiedemann), the Mediterranean fruit fly or medfly, is one of the world's most serious threats to fresh fruits. It is highly polyphagous (recorded from over 300 hosts) and capable of adapting to a wide range of climates. This pest has spread to the EPPO region and is mainly present in the southern part, damaging Citrus and Prunus. In Northern and Central Europe records refer to interceptions or short-lived adventive populations only. Sustainable programs for surveillance, spread assessment using models and control strategies for pests such as C. capitata represent a major plant health challenge for all countries in Europe. This article includes a review of pest distribution and monitoring techniques in 11 countries of the EPPO region. This work compiles information that was crucial for a better understanding of pest occurrence and contributes to identifying areas susceptible to potential invasion and establishment. The key outputs and results obtained in the Euphresco project included knowledge transfer about early detection tools and methods used in different countries for pest monitoring. A MaxEnt software model resulted in risk maps for C. capitata in different climatic regions. This is an important tool to help decision making and to develop actions against this pest in the different partner countries