228 research outputs found

    Performance, emissions, and physical characteristics of a rotating combustion aircraft engine, supplement A

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    Testing was conducted using the basic RC2-75 engine, to which several modifications were incorporated which were designed to reduce the hydrocarbon emissions and reduce the specific fuel consumption. The modifications included close-in surface gap spark plugs, increased compression ratio rotors, and provisions for utilizing either side or peripheral intake ports, or a combination of the two if required. The proposed EPA emissions requirements were met using the normal peripheral porting. The specific fuel economy demonstrated for the modified RC2-75 was 283 g/kW-hr at 75% power and 101 brake mean effective pressure (BMEP) and 272.5 g/kW-hr at 75% power and 111 BMEP. The latter would result from rating the engine for takeoff at 285 hp and 5500 rpm, instead of 6000 rpm

    Modelling Clock Synchronization in the Chess gMAC WSN Protocol

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    We present a detailled timed automata model of the clock synchronization algorithm that is currently being used in a wireless sensor network (WSN) that has been developed by the Dutch company Chess. Using the Uppaal model checker, we establish that in certain cases a static, fully synchronized network may eventually become unsynchronized if the current algorithm is used, even in a setting with infinitesimal clock drifts

    Parameter estimation of the kinetic α-Pinene isomerization model using the MCSfilter algorithm

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    This paper aims to illustrate the application of a derivative-free multistart algorithm with coordinate search filter, designated as the MCSFilter algorithm. The problem used in this study is the parameter estimation problem of the kinetic α -pinene isomerization model. This is a well known nonlinear optimization problem (NLP) that has been investigated as a case study for performance testing of most derivative based methods proposed in the literature. Since the MCSFilter algorithm features a stochastic component, it was run ten times to solve the NLP problem. The optimization problem was successfully solved in all the runs and the optimal solution demonstrates that the MCSFilter provides a good quality solution.(undefined)info:eu-repo/semantics/publishedVersio

    UbiqLog: a generic mobile phone based life-log framework

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    Smart phones are conquering the mobile phone market; they are not just phones they also act as media players, gaming consoles, personal calendars, storage, etc. They are portable computers with fewer computing capabilities than personal computers. However unlike personal computers users can carry their smartphone with them at all times. The ubiquity of mobile phones and their computing capabilities provide an opportunity of using them as a life logging device. Life-logs (personal e-memories) are used to record users' daily life events and assist them in memory augmentation. In a more technical sense, life-logs sense and store users' contextual information from their environment through sensors, which are core components of life-logs. Spatio-temporal aggregation of sensor information can be mapped to users' life events. We propose UbiqLog, a lightweight, configurable and extendable life-log framework that uses mobile phone as a device for life logging. The proposed framework extends previous research in this field, which investigated mobile phones as life-log tool through continuous sensing. Its openness in terms of sensor configuration allows developers to create exible, multipurpose life-log tools. In addition to that this framework contains a data model and an architecture, which can be used as reference model for further life-log development, including its extension to other devices, such as ebook readers, T.V.s, etc

    First-Trimester Follistatin-Like-3 Levels in Pregnancies Complicated by Subsequent Gestational Diabetes Mellitus

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    Objective: To determine whether maternal levels of follistatin-like-3 (FSTL3), an inhibitor of activin and myostatin involved in glucose homeostasis, are altered in the first trimester of pregnancies complicated by subsequent gestational diabetes mellitus (GDM). Research Design and Methods: This was a nested case-control study of subjects enrolled in a prospective cohort of pregnant women with and without GDM (\geq2 abnormal values on a 100-g glucose tolerance test at ~28 weeks of gestation). We measured FSTL3 levels in serum collected during the first trimester of pregnancy. Logistic regression analyses were used to determine the risk of GDM. Results: Women who developed GDM (n = 37) had lower first-trimester serum levels of FSTL3 compared with women who did not (n = 127) (median 10,789 [interquartile range 7,013-18,939] vs. 30,670 [18,370-55,484] pg/ml, P < 0.001). When subjects were divided into tertiles based on FSTL3 levels, women with the lowest levels demonstrated a marked increase in risk for developing GDM in univariate (odds ratio 11.2 [95% CI 3.6-35.3]) and multivariate (14.0 [4.1-47.9]) analyses. There was a significant negative correlation between first-trimester FSTL3 levels and ~28-week nonfasting glucose levels (r = -0.30, P < 0.001). Conclusions: First-trimester FSTL3 levels are associated with glucose intolerance and GDM later in pregnancy

    The human resource for health situation in Zambia: deficit and maldistribution

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    <p>Abstract</p> <p>Introduction</p> <p>Current health policy directions in Zambia are formulated in the National Health Strategic Plan. The Plan focuses on national health priorities, which include the human resources (HR) crisis. In this paper we describe the way the HRH establishment is distributed in the different provinces of Zambia, with a view to assess the dimension of shortages and of imbalances in the distribution of health workers by province and by level of care.</p> <p>Population and methods</p> <p>We used secondary data from the "March 2008 payroll data base", which lists all the public servants on the payroll of the Ministry of Health and of the National Health Service facilities. We computed rates and ratios and compared them.</p> <p>Results</p> <p>The highest relative concentration of all categories of workers was observed in Northern, Eastern, Lusaka, Western and Luapula provinces (in decreasing order of number of health workers).</p> <p>The ratio of clinical officers (mid-level clinical practitioners) to general medical officer (doctors with university training) varied from 3.77 in the Lusaka to 19.33 in the Northwestern provinces. For registered nurses (3 to 4 years of mid-level training), the ratio went from 3.54 in the Western to 15.00 in Eastern provinces and for enrolled nurses (two years of basic training) from 4.91 in the Luapula to 36.18 in the Southern provinces.</p> <p>This unequal distribution was reflected in the ratio of population per cadre. The provincial distribution of personnel showed a skewed staff distribution in favour of urbanized provinces, e.g. in Lusaka's doctor: population ratio was 1: 6,247 compared to Northern Province's ratio of 1: 65,763.</p> <p>In the whole country, the data set showed only 109 staff in health posts: 1 clinical officer, 3 environmental health technologists, 2 registered nurses, 12 enrolled midwives, 32 enrolled nurses, and 59 other.</p> <p>The vacancy rates for level 3 facilities(central hospitals, national level) varied from 5% in Lusaka to 38% in Copperbelt Province; for level 2 facilities (provincial level hospitals), from 30% for Western to 70% for Copperbelt Province; for level 1 facilities (district level hospitals), from 54% for the Southern to 80% for the Western provinces; for rural health centres, vacancies varied from 15% to 63% (for Lusaka and Luapula provinces respectively); for urban health centres the observed vacancy rates varied from 13% for the Lusaka to 96% for the Western provinces. We observed significant shortages in most staff categories, except for support staff, which had a significant surplus.</p> <p>Discussion and Conclusions</p> <p>This case study documents how a peaceful, politically stable African country with a longstanding tradition of strategic management of the health sector and with a track record of innovative approaches dealt with its HRH problems, but still remains with a major absolute and relative shortage of health workers. The case of Zambia reinforces the idea that training more staff is necessary to address the human resources crisis, but it is not sufficient and has to be completed with measures to mitigate attrition and to increase productivity.</p

    Clonal diversity and detection of carbapenem resistance encoding genes among multidrug-resistant Acinetobacter baumannii isolates recovered from patients and environment in two intensive care units in a Moroccan hospital

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    Background Carbapenem-resistant Acinetobacter baumannii has recently been defined by the World Health Organization as a critical pathogen. The aim of this study was to compare clonal diversity and carbapenemase-encoding genes of A. baumannii isolates collected from colonized or infected patients and hospital environment in two intensive care units (ICUs) in Morocco. Methods The patient and environmental sampling was carried out in the medical and surgical ICUs of Mohammed V Military teaching hospital from March to August 2015. All A. baumannii isolates recovered from clinical and environmental samples, were identified using routine microbiological techniques and Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry. Antimicrobial susceptibility testing was performed using disc diffusion method. The carbapenemase-encoding genes were screened for by PCR. Clonal relatedness was analyzed by digestion of the DNA with low frequency restriction enzymes and pulsed field gel electrophoresis (PFGE) and the multi locus sequence typing (MLST) was performed on two selected isolates from two major pulsotypes. Results A total of 83 multidrug-resistant A. baumannii isolates were collected: 47 clinical isolates and 36 environmental isolates. All isolates were positive for the bla OXA51-like and bla OXA23-like genes. The coexistence of bla NDM-1 /bla OXA-23-like and bla OXA 24-like /bla OXA-23-like were detected in 27 (32.5%) and 2 (2.4%) of A. baumannii isolates, respectively. The environmental samples and the fecally-colonized patients were significantly identified (p < 0.05) as the most common sites of isolation of NDM-1-harboring isolates. PFGE grouped all isolates into 9 distinct clusters with two major groups (0007 and 0008) containing up to 59% of the isolates. The pulsotype 0008 corresponds to sequence type (ST) 195 while pulsotype 0007 corresponds to ST 1089.The genetic similarity between the clinical and environmental isolates was observed in 80/83 = 96.4% of all isolates, belonging to 7 pulsotypes. Conclusion This study shows that the clonal spread of environmental A. baumannii isolates is related to that of clinical isolates recovered from colonized or infected patients, being both associated with a high prevalence of the bla OXA23-like and bla NDM-1genes. These findings emphasize the need for prioritizing the bio-cleaning of the hospital environment to control and prevent the dissemination of A. baumannii clonal lineages

    Statistical Estimation of T1 Relaxation Time Using Conventional Magnetic Resonance Imaging

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    Quantitative T1 maps estimate T1 relaxation times and can be used to assess diffuse tissue abnormalities within normal-appearing tissue. T1 maps are popular for studying the progression and treatment of multiple sclerosis (MS). However, their inclusion in standard imaging protocols remains limited due to the additional scanning time and expert calibration required and susceptibility to bias and noise. Here, we propose a new method of estimating T1 maps using four conventional MR images, which are intensity- normalized using cerebellar gray matter as a reference tissue and related to T1 using a smooth regression model. Using leave-one-out cross-validation, we generate statistical T1 maps for 61 subjects with MS. The statistical maps are less noisy than the acquired maps and show similar accuracy. Tests of group differences in normal-appearing white matter across MS subtypes give similar results using both methods, but tests performed using statistical maps are more powerful

    Personal endotoxin exposure in a panel study of school children with asthma

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    <p>Abstract</p> <p>Background</p> <p>Endotoxin exposure has been associated with asthma exacerbations and increased asthma prevalence. However, there is little data regarding personal exposure to endotoxin in children at risk, or the relation of personal endotoxin exposure to residential or ambient airborne endotoxin. The relation between personal endotoxin and personal air pollution exposures is also unknown.</p> <p>Methods</p> <p>We characterized personal endotoxin exposures in 45 school children with asthma ages 9-18 years using 376 repeated measurements from a PM<sub>2.5 </sub>active personal exposure monitor. We also assayed endotoxin in PM<sub>2.5 </sub>samples collected from ambient regional sites (N = 97 days) and from a subset of 12 indoor and outdoor subject home sites (N = 109 and 111 days, respectively) in Riverside and Whittier, California. Endotoxin was measured using the Limulus Amoebocyte Lysate kinetic chromogenic assay. At the same time, we measured personal, home and ambient exposure to PM<sub>2.5 </sub>mass, elemental carbon (EC), and organic carbon (OC). To assess exposure relations we used both rank correlations and mixed linear regression models, adjusted for personal temperature and relative humidity.</p> <p>Results</p> <p>We found small positive correlations of personal endotoxin with personal PM<sub>2.5 </sub>EC and OC, but not personal PM<sub>2.5 </sub>mass or stationary site air pollutant measurements. Outdoor home, indoor home and ambient endotoxin were moderately to strongly correlated with each other. However, in mixed models, personal endotoxin was not associated with indoor home or outdoor home endotoxin, but was associated with ambient endotoxin. Dog and cat ownership were significantly associated with increased personal but not indoor endotoxin.</p> <p>Conclusions</p> <p>Daily fixed site measurements of endotoxin in the home environment may not predict daily personal exposure, although a larger sample size may be needed to assess this. This conclusion is relevant to short-term exposures involved in the acute exacerbation of asthma.</p
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