29 research outputs found

    On the feasibility of using IEEE 802.11ad mmWave for accurate object detection

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    Millimeter wave (mmWave) bands are considered highly for localization and object detection. In this paper we assess the potential of commercial IEEE 802.11ad mmWave equipment to offer accurate object detection, ultimately providing models of the physical environment. Unlike solutions using bespoke mmWave equipment for detection, the use of IEEE 802.11ad ensures a low-cost system, and one in which detection can be integrated with communication, creating potential for innovative applications. Our approach is to build a laboratory testbed in which we capture reflected mmWave signals that are generated and transmitted by a commercial off-the-shelf (COTS) IEEE 802.11ad mmWave device. From the measured channel impulse response, we measured the distance from the mmWave transceiver to the objects in the environment, by some simple signal processing techniques. By knowing the angle of mmWave departure/arrival and this measured distance, we can develop a 2D model of the physical environment. We report on the achieved accuracy, which is 2cm in most experiments, and discuss technology limitations and research opportunities

    Prevalence of dyslipidaemia and associated risk factors in a rural population in south-western Uganda : a community based survey

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    BACKGROUND: The burden of dyslipidaemia is rising in many low income countries. However, there are few data on the prevalence of, or risk factors for, dyslipidaemia in Africa. METHODS: In 2011, we used the WHO Stepwise approach to collect cardiovascular risk data within a general population cohort in rural south-western Uganda. Dyslipidaemia was defined by high total cholesterol (TC) ≥ 5.2 mmol/L or low high density lipoprotein cholesterol (HDL-C) 6% (men aOR=3.00, 95%CI=1.37-6.59; women aOR=2.74, 95%CI=1.77-4.27). The odds of high TC was also higher among married men, and women with higher education or high BMI. CONCLUSION: Low HDL-C prevalence in this relatively young rural population is high whereas high TC prevalence is low. The consequences of dyslipidaemia in African populations remain unclear and prospective follow-up is required

    Climatic, edaphic factors and cropping history help predict click beetle (Coleoptera: Elateridae) (Agriotes spp.) abundance

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    It is assumed that the abundance of Agriotes wireworms (Coleoptera: Elateridae) is affected by agro-ecological factors such as climatic and edaphic factors and the crop/previous crop grown at the sites investigated. The aim of this study, conducted in three different geographic counties in Croatia from 2007 to 2009, was to determine the factors that influence the abundance of adult click beetle of the species Agriotes brevis Cand., Agriotes lineatus (L.), Agriotes obscurus (L.), Agriotes sputator (L.), and Agriotes ustulatus Schall. The mean annual air temperature, total rainfall, percentage of coarse and fine sand, coarse and fine silt and clay, the soil pH, and humus were investigated as potential factors that may influence abundance. Adult click beetle emergence was monitored using sex pheromone traps (YATLORf and VARb3). Exploratory data analysis was preformed via regression tree models and regional differences in Agriotes species\u27 abundance were predicted based on the agro-ecological factors measured. It was found that the best overall predictor of A. brevis abundance was the previous crop grown. Conversely, the best predictor of A. lineatus abundance was the current crop being grown and the percentage of humus. The best predictor of A. obscurus abundance was soil pH in KCl. The best predictor of A. sputator abundance was rainfall. Finally, the best predictors of A. ustulatus abundance were soil pH in KCl and humus. These results may be useful in regional pest control programs or for predicting future outbreaks of these species

    Ethnic differences in behavioural risk factors for stroke: implications for health promotion

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    Objectives. Ethnic minority groups are at a higher risk of stroke and heart disease. However, designing effective prevention strategies requires responding to the needs of different ethnic groups. The aims of this study were to estimate the prevalence of four behavioural risk factors (smoking, drinking, exercise and weight) for stroke among Black Caribbeans, Black Africans and Whites, and also to examined reported willingness to change these behaviours. Design. A random sample of 311 Black Caribbean, 300 White, and 105 Black Africans aged 45-74 registered with 16 practices in south London were surveyed in 1995. Information was obtained on smoking, drinking and exercise patterns, body mass index and perceptions of being at risk of stroke, and willingness to change risk behaviour. Results. White respondents (31% age and sex standardised prevalence) were more likely to smoke than Black Caribbeans (23%) and Black Africans (10%) (p < 0.001). Self-reported rates of drinking were higher than the government's 'sensible drinking levels' for 19% of Whites, 11% of Black Caribbeans and 4% Black Africans (p < 0.001). In contrast, fewer Whites (51%) were overweight (BMI > 27) than Black Caribbeans (60%) and Black Africans (68%) (p = 0.001). A high proportion of smokers wished to give up (89% Black African; 83% Black Caribbean; 74% White). A higher proportion of Black Caribbeans (35%) reported a willingness to reduce their alcohol intake compared to only 15% of Whites (p = 0.040). There was a difference between groups in attitudes to weight reduction with 69% Black Caribbean women expressing a desire to be thinner compared to 86% Whites and 82% Black Africans (p = 0.051). Conclusion. Strategies to reduce behavioural risk factors for heart attack and stroke need to emphasise different risk factors among ethnic groups, especially in relation to alcohol use in the White population and weight in the Black Caribbean population. Influencing the change of these behaviours requires working in partnership with local community groups

    Finite element analysis of vertically loaded cylindrical Ti implants

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    The following study was conducted in order to evaluate the effects of height, width and design variations on the stress distribution of vertically loaded, cylindrical titanium implants using finite element analysis (FEA). Three groups of cylindrical titanium TPS surface implants (Premium, Sweden & Martina, Italy) inserted into mandible segments were analysed. The three Premium implants in the first group were of different length (10.0, 11.5 and 13.0 mm) but possessed the same diameter of 3.80 mm. The second group consisted of three Premium implants with the same length of 11.5 mm but with different diameters (3.30, 3.80 and 4.25 mm). In the last group two different implant designs were compared, one featuring platform switching and a straight emergence profile and the other without platform switching. Overall, eight implant-bone samples were analyzed and the resulting stress distributions during vertical loading were obtained. For all eight samples, maximum stress values were found in the area of the implant neck and the stress values decreased in the apical direction. The higher stress values in the second group were detected in the implant with smaller diameter. It was noted that the implant with platform switching experienced lower stresses than the one without platform switching. Changes in length did not have any significant effect on the stress distribution. Under a vertical occlusal load, an implant with a larger diameter and with platform switching had the most favorable stress distribution throughout the implant structure and the adjacent bone tissue
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