| 282. |
- Vanfretti, Luigi, et al.
(författare)
-
Application of ambient analysis techniques for the estimation of electromechanical oscillations from measured PMU data in four different power systems
- 2011
-
Ingår i: European transactions on electrical power. - : Wiley-Blackwell. - 1430-144X .- 1546-3109. ; 21:4, s. 1640-1656
-
Tidskriftsartikel (refereegranskat)abstract
- The application of advanced signal processing techniques to power system measurement data for the estimation of dynamic properties has been a research subject for over two decades. Several techniques have been applied to transient (or ringdown) data, ambient data, and to probing data. Some of these methodologies have been included in off-line analysis software, and are now being incorporated into software tools used in control rooms for monitoring the near real-time behavior of power system dynamics. In this paper we illustrate the practical application of some ambient analysis methods for electromechanical mode estimation in different power systems. We apply these techniques to phasor measurement unit (PMU) data from stored archives of several hours originating from the US Eastern Interconnection (EI), the Western Electricity Coordinating Council (WECC), the Nordic Power System, and time-synchronized Frequency Disturbance Recorder (FDR) data from Nigeria. It is shown that available signal processing tools are readily applicable for analysis of different power systems, regardless of their specific dynamic characteristics. The discussions and results in this paper are of value to power system operators and planners as they provide information of the applicability of these techniques via readily available signal processing tools, and in addition, it is shown how to critically analyze the results obtained with these methods.
|
|
| 285. |
- Yusuf, S., et al.
(författare)
-
Use of secondary prevention drugs for cardiovascular disease in the community in high-income, middle-income, and low-income countries (the PURE Study): a prospective epidemiological survey
- 2011
-
Ingår i: Lancet. - 1474-547X. ; 378:9798, s. 1231-43
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Although most cardiovascular disease occurs in low-income and middle-income countries, little is known about the use of effective secondary prevention medications in these communities. We aimed to assess use of proven effective secondary preventive drugs (antiplatelet drugs, beta blockers, angiotensin-converting-enzyme [ACE] inhibitors or angiotensin-receptor blockers [ARBs], and statins) in individuals with a history of coronary heart disease or stroke. METHODS: In the Prospective Urban Rural Epidemiological (PURE) study, we recruited individuals aged 35-70 years from rural and urban communities in countries at various stages of economic development. We assessed rates of previous cardiovascular disease (coronary heart disease or stroke) and use of proven effective secondary preventive drugs and blood-pressure-lowering drugs with standardised questionnaires, which were completed by telephone interviews, household visits, or on patient's presentation to clinics. We report estimates of drug use at national, community, and individual levels. FINDINGS: We enrolled 153,996 adults from 628 urban and rural communities in countries with incomes classified as high (three countries), upper-middle (seven), lower-middle (three), or low (four) between January, 2003, and December, 2009. 5650 participants had a self-reported coronary heart disease event (median 5.0 years previously [IQR 2.0-10.0]) and 2292 had stroke (4.0 years previously [2.0-8.0]). Overall, few individuals with cardiovascular disease took antiplatelet drugs (25.3%), beta blockers (17.4%), ACE inhibitors or ARBs (19.5%), or statins (14.6%). Use was highest in high-income countries (antiplatelet drugs 62.0%, beta blockers 40.0%, ACE inhibitors or ARBs 49.8%, and statins 66.5%), lowest in low-income countries (8.8%, 9.7%, 5.2%, and 3.3%, respectively), and decreased in line with reduction of country economic status (p(trend)<0.0001 for every drug type). Fewest patients received no drugs in high-income countries (11.2%), compared with 45.1% in upper middle-income countries, 69.3% in lower middle-income countries, and 80.2% in low-income countries. Drug use was higher in urban than rural areas (antiplatelet drugs 28.7% urban vs 21.3% rural, beta blockers 23.5%vs 15.6%, ACE inhibitors or ARBs 22.8%vs 15.5%, and statins 19.9%vs 11.6%; all p<0.0001), with greatest variation in poorest countries (p(interaction)<0.0001 for urban vs rural differences by country economic status). Country-level factors (eg, economic status) affected rates of drug use more than did individual-level factors (eg, age, sex, education, smoking status, body-mass index, and hypertension and diabetes statuses). INTERPRETATION: Because use of secondary prevention medications is low worldwide-especially in low-income countries and rural areas-systematic approaches are needed to improve the long-term use of basic, inexpensive, and effective drugs. FUNDING: Full funding sources listed at end of paper (see Acknowledgments).
|
|
