منابع مشابه
An Introduction to Natural Experiment Studies
در دو سخن سردبیری شمارههای قبل به مطالعات مداخلهای (Interventional and/or experimental studies) [1] و مطالعات نیمه تجربی (studies Quasi-experiment) [2] پرداختیم. همان جا، به این نکته اشاره کردیم که برای اندازهگیری کارآیی یک دارو، واکسن، برنامه بهداشت عمومی و متغیرهای دیگری از این دست، مطالعات مداخلهای بهترین گزینه هستند. تقسیم تصادفی و کورسازی از مؤلفههای اساسی یک مطالعه مداخلهای است [1]....
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in the area of automotive engineering there is a tendency to more electrification of power train. in this work control of an induction machine for the application of electric vehicle is investigated. through the changing operating point of the machine, adapting the rotor magnetization current seems to be useful to increase the machines efficiency. in the literature there are many approaches wh...
15 صفحه اولA ray model of sound focusing with a balloon lens: an experiment for high school students.
A weather balloon filled with carbon dioxide gas is used as a positive spherical acoustic lens. High frequency but audible sound from a circular loudspeaker ensonifies the balloon and produces increased sound pressure levels in a region along the principal axis according to a ray acoustics model. This enhancement was measured experimentally and was found to agree with theory. The possibility th...
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Background A growing body of public management literature sheds light on potential shortcomings to quality improvement (QI) and performance management efforts. These challenges stem from heuristics individuals use when interpreting data. Evidence from studies of citizens suggests that individuals’ evaluation of data is influenced by the linguistic framing or context of that information an...
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ژورنال
عنوان ژورنال: Scientific American
سال: 1910
ISSN: 0036-8733
DOI: 10.1038/scientificamerican05281910-446a