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 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

A cross-sectional assessment of metabolic syndrome in HIV-infected people of low socioeconomic status receiving antiretroviral therapy

BACKGROUND: Metabolic syndrome (MetS) is a constellation of symptoms used as a measure to identify patients at increased risk for cardiovascular disease, type 2 diabetes, and all-cause mortality. The results of prolonged life expectancy and cumulative toxic effects of antiretroviral therapy increase the chance that HIV can cause clinical abnormalities, including MetS. METHODS: We evaluated 89 people living with HIV (PLWH; mean age 48 ± 7 years; mean duration of HIV infection 17 ± 12 years; 47% men; 66% African-American, 22% Hispanic, and 10% non-Hispanic white; and 84% unemployed) enrolled in a community-based exercise training and nutrition education program targeting individuals of low socio-economic status (SES). The prevalence of MetS characteristics and the factors associated with the presence of MetS were analyzed. RESULTS: One in three (33%; 12 men and 17 women) PLWH met ATPIII criteria for MetS. In our cohort, MetS was driven by high waist circumference and elevated blood pressure. In addition, higher use of protease inhibitors, elevated hemoglobin A1c (HbA1c), greater self-reported daily caloric intake and consumption of carbohydrates, sugar, added sugar, and higher glycemic load were found among the individuals with MetS, compared to those without it. Elevated HbA1c and high total sugar consumption were the strongest predictors and accounted for 30% of the occurrence of MetS. CONCLUSIONS: The overall prevalence of MetS in our PLWH cohort receiving antiretroviral therapy is higher than previously reported in the general population and in other PLWH cohorts. Additional work is needed to determine whether MetS is a more disease dependent or lifestyle dependent condition in PLWH

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

Pediatric Hand Treadmill Injuries

The great popularity of physical fitness in modern society has brought many pieces of exercise equipment into our homes for convenience and privacy. This trend has come with an increasing rate of injuries to children who curiously touch moving parts, including treadmill belts. Experience with a recent series of treadmill contact burns to children&apos;s hands is described in this article. A retrospective chart review at a tertiary referral center from June 1998 until June 2001 found six children sustaining hand burns from treadmills. The patients&apos; ages at presentation ranged from 15 to 45 months (average of 31 months, three boys and three girls). All injuries occurred in the home while a parent was using the treadmill. Burns involved the palmar aspect of the hand, mostly confined to the fingers, and the severity ranged from partialto full-thickness burns. All patients were initially managed with collagenase and bacitracin zinc/polymyxin B powder dressings to second-and third-degree burns, along with splinting and rangeof-motion exercises. Two patients required skin grafting at 2 weeks and 2 months for full-thickness tissue loss and tight joint contracture, respectively. At an average follow-up of 12 months, all patients had full range of motion and no physical limitation. The rate of children injured by exercise equipment is expected to increase. Friction burns to the hands remain a concern, although early recognition and appropriate management are associated with excellent functional outcomes. Protective modification of exercise machines seems to be the best approach to eliminating these injuries

Effect of Dupilumab on Sleep Apnea Severity in Patients With Chronic Rhinosinusitis

Patients with chronic rhinosinusitis (CRS) report improved sleep quality after dupilumab, an anti IL4/13 therapy. Concurrent CRS and obstructive sleep apnea (OSA) cases are not rare, and CRS seemingly raises nasal resistance. Thus, we hypothesized that improved sleep quality by dupilumab therapy in CRS patients might be due to lowered nasal resistance and subsequent improvement of unrecognized comorbid OSA. Patients with concurrent CRS and OSA were recruited. Nasal resistance was measured invasively with transnasal pressure and flow data collected during normal respiration in the supine position. Results from the first five participants did not support our hypothesis. Subjective and objective measures for CRS and nasal resistance values were improved with dupilumab therapy in CRS patients with nasal polyps. However, apnea severity and sleep-related subjective parameters did not change. In the patients with CRS without nasal polyps, no significant changes in either CRS or OSA-related measures were observed

Critical Dietetics and Sustainable Food Systems

In this chapter, we invite readers to consider a food system that is based on values where individual health, the health of the society (social system) and ecosystem health are of equal importance. With this as a lens, there is a clear need to move beyond the biosciences to consider transdisciplinary approaches as important for nutrition and Dietetic in today and tomorrow’s reality