Prospective Cohort Study

25. Multiple Imputation for Nonresponse in Surveys. By D. B. Rubin. ISBN 0 471 08705 X. Wiley, Chichester, 1987. 258 pp. £30.25.

Multiple Imputation for Nonresponse in Surveys

Much has been written about theory and practice in the law, and the tension between practitioners and theorists. Judges do not cite theoretical articles often; they rarely "apply" theories to particular cases. These arguments are not revisited. Instead the Essay explores the working and interaction of theory and practice, practitioners and theorists. The Essay starts with a story about solving a legal issue using our intellectual tools - theory, practice, and their progenies: experience and "gut." Next the Essay elaborates on the nature of theory, practice, experience and "gut." The third part of the Essay discusses theories that are helpful to practitioners and those that are less helpful. The Essay concludes that practitioners theorize, and theorists practice. They use these intellectual tools differently because the goals and orientations of theorists and practitioners, and the constraints under which they act, differ. Theory, practice, experience and "gut" help us think, remember, decide and create. They complement each other like the two sides of the same coin: distinct but inseparable.

Of Theory and Practice

Definition: To what extent does the study allow us to draw conclusions about a causal effect between two or more constructs? Issues: Selection, maturation, history, mortality, testing, regression towrd the mean, selection by maturation, treatment by mortality, treatment by testing, measured treatment variables Increase: Eliminate the threats, above all do experimental manipulations, random assignment, and counterbalancing.

Reliability and validity

저작근 근전도에 관한 정상교합자와 ii급 부정교합자의 비교 연구

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0218 Effects Of Sleep Deprivation And Recovery Sleep On Human Brain Network Organization

As part of the NORAH study the German Aerospace Center (DLR) examined during three measurement periods in 2011-2013 the "Effects of aircraft noise on sleep" around Frankfurt airport before and after the implementation of a night flight ban (11 p.m. - 5 a.m.) in October 2011. 
A total of 202 healthy adult airport residents aged 18 to 78 years were investigated at their homes during these three study years. Polysomnograms of 49 subjects in 2011 and 83 subjects in 2012 were recorded for three nights each. In 2013, a total of 187 volunteers were examined for 3 nights with a less expensive method, measuring heart rate and body movements in order to assess vegetativ-motoric reactions to noise. In each study year, the sound pressure level and the noise at night were continuously registered at the sleeper's ear. 
Exposure-response curves representing the awakening/vegetative-motoric reaction probabilities for an overflight depending on the maximum sound pressure level were calculated for the different years as well as sleep quality parameters for 2011 and 2012. Sleep behavior of two bed time groups (one exposed to aircraft noise in the evening and in the morning, the other just in the morning) were compared.

The NORAH-Sleep Study: Effects of the Night Flight Ban at Frankfurt Airport

Large quantities of carbon dioxide (CO2) originate from human metabolism and typically, within spacecraft, remain about 10-fold higher in concentration than at the earth's surface. There have been recurring complaints by crew members of episodes of "mental viscosity" adversely affecting their performance, and there is evidence from the International Space Station (ISS) that associates CO2 levels with reports of headaches by crewmembers. Additionally, there is concern that CO2 may contribute to vision impairment and intracranial pressure that has been observed in some crewmembers. Consequently, flight rules have been employed to control the level of CO2 below 4 mm Hg, which is well below the existing Spacecraft Maximum Allowable Concentration (SMAC) of 10 mm Hg for 24-hour exposures, and 5.3 mm Hg for exposures of 7 to 180 days. However, the flight rule imposed limit, which places additional demands upon resources and current technology, still exceeds the lower bound of the threshold range for reportable headaches (2 - 5 mm Hg). Headaches, while sometime debilitating themselves, are also symptoms that can provide evidence that physiological defense mechanisms have been breached. The causes of the headaches may elicit other subtle adverse effects that occur at CO2 levels well below that for headaches. The concern that CO2 may have effects at levels below the threshold for headaches appears to be substantiated in unexpected findings that CO2 at concentrations below 2 mm Hg substantially reduced some cognitive functions that are associated with the ability to make complex decisions in conditions that are characterized by volatility, uncertainty, complexity, ambiguity, and delayed feedback. These are conditions that could be encountered by crews in off-nominal situations or during the first missions beyond low earth orbit. If findings of the earlier study are confirmed in crew-like subjects, our findings would provide additional evidence that CO2 may need to be controlled at levels that are well below current spacecraft limits. Our study will extend the earlier study to determine if crew-like subjects are similarly effected by CO2. In addition to employing the Strategic Management Simulation tool, we will use the Cognition battery of psychometric measures that are being utilized aboard the ISS. It will be important to learn, by using Cognition, if additional cognitive domains are sensitive to concentrations of CO2 at or below limits currently controlled by flight rules. While spaceflight Cognition data will greatly enhance the knowledge base related to inflight behavioral health and performance, some of the measures may be influenced by fatigue (related to sleep deprivation and or workload) and changes in circadian rhythms. Therefore our use of this battery of tests in a well-controlled, ground-based study that is free of these potential confounding influences will establish a baseline terrestrial data set against which Cognition data collected in flight may be assessed. The findings from this study will be useful to the NASA Toxicology Office and the National Research Council Committee on Toxicology, which assists NASA in setting environmental standards, for revision of the SMAC for CO2, and for designing further studies on effects of CO2 upon cognitive functions.

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Effects of Acute Exposures to Carbon Dioxide Upon Cognitive Functions

Within the planning process concerning the future expansion of Frankfurt Airport (construction of a new runway) in September 2007 the Regional Dialogue Forum Frankfurt Airport (RDF) proposed an Anti-Noise-Pact (ANP). ANP includes suggestions of upper limits and quantitative reduction goals for noise effects after the airport expansion and recommends the implementation of active noise control measures. Moreover, two regional aircraft noise indices for the description and control of the noise development in the vicinity of Frankfurt Airport are proposed. These are the 'Frankfurt Aircraft Noise Index' (FFI), and 'Frankfurt Night Index' (FNI). FFI is the primary index. Based on the 24 hours of the day, it describes the number of subjects highly annoyed by aircraft noise in areas within Ldn -contour 55 dB. FNI solely serves to assess nocturnal air traffic by displaying the number of awakenings additionally induced by aircraft noise emitted between 10pm and 6am, including regions where at least 0.5 additionally aircraft noise induced awakenings are expected. The proposed indices were subjected to a scientific evaluation by the authors of this contribution. In this contribution FFI and FNI and the involved requirements and objectives are described. It is concluded that effect based noise indices like FFI and FNI are in principle suitable to assess aircraft noise development around the airport as far as the underlying noise calculation method is able to reproduce the acoustical effects of changes in air traffic. However, several recommendations are given in order to improve the indices initially proposed by RDF.

FFI and FNI - two effect based aircraft noise indices at Frankfurt Airport

AIM: To test the hypothesis that aircraft noise causes more awakenings and alterations of sleep structure than rail and road traffic noise. METHODS: 12 women and 12 men (19-28 years) slept, following a habituation night, 4 nights each during 3 consecutive weeks in the laboratory. They were exposed with weekly changes to road-, rail-, or aircraft noise. Each week consisted of a random sequence of a quiet night and 3 nights with equivalent noise levels of 39, 44 and 50 dBA indoors. The polysomnogram was recorded throughout all nights, sleep quality was assessed and performance tests were completed in the morning. RESULTS: Noise-induced awakenings and structural parameters of sleep, subjective quality and performance indicated more disturbances with increasing noise levels. Where decreased subjective sleep quality was not related to the type of noise, noise-induced awakenings and other physiological parameters of sleep were most affected by rail and least by road traffic noise. CONCLUSIONS: As road-, rail- and aircraft noise caused the same after-effects but different physiological effects integrated noise metrics might be suitable for the prediction of subjective sleep quality but not for the physiological disturbances of sleep.

Mathias Basner

Papers

0218 Effects Of Sleep Deprivation And Recovery Sleep On Human Brain Network Organization

The NORAH-Sleep Study: Effects of the Night Flight Ban at Frankfurt Airport

Effects of Acute Exposures to Carbon Dioxide Upon Cognitive Functions

FFI and FNI - two effect based aircraft noise indices at Frankfurt Airport

Awakenings related to noises from various traffic modes