104 research outputs found

    Space Station CMIF extended duration metabolic control test

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    The Space Station Extended Duration Metabolic Control Test (EMCT) was conducted at the MSFC Core Module Integration Facility. The primary objective of the EMCT was to gather performance data from a partially-closed regenerative Environmental Control and Life Support (ECLS) system functioning under steady-state conditions. Included is a description of the EMCT configuration, a summary of events, a discussion of anomalies that occurred during the test, and detailed results and analysis from individual measurements of water and gas samples taken during the test. A comparison of the physical, chemical, and microbiological methods used in the post test laboratory analyses of the water samples is included. The preprototype ECLS hardware used in the test, providing an overall process description and theory of operation for each hardware item. Analytical results pertaining to a system level mass balance and selected system power estimates are also included

    Uncertainty causes rounding: an experimental study

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    Rounding is a common phenomenon when subjects provide an answer to an open-ended question, both in experimental tasks and in survey responses. From a statistical perspective, rounding implies that the measured variable is a coarsened version of the underlying continuous target variable. Since the coarsening process is non-random, inference from rounded data is generally biased. Despite the potentially severe consequences of rounding, little is known about its causes. In this paper, we focus on subjects' uncertainty about the target variable as one potential cause for rounding behavior. We present a novel experimental method that induces uncertainty in a controlled way, thus providing causal evidence for the effect of subjects' uncertainty on the extent of rounding. Then, we specify and estimate a mixture model that relates uncertainty and rounding. The results suggest that an increase in the exogenous level of uncertainty translates into higher variance of the subjects' beliefs, which in turn results in more rounding

    Energy losses of low-energy photoelectrons to thermal electrons

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33736/1/0000251.pd

    Epidemiology and clinical features of vivax malaria imported to Europe: Sentinel surveillance data from TropNetEurop

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    BACKGROUND: Plasmodium vivax is the second most common species among malaria patients diagnosed in Europe, but epidemiological and clinical data on imported P. vivax malaria are limited. The TropNetEurop surveillance network has monitored the importation of vivax malaria into Europe since 1999. OBJECTIVES: To present epidemiological and clinical data on imported P. vivax malaria collected at European level. MATERIAL AND METHODS: Data of primary cases of P. vivax malaria reported between January 1999 and September 2003 were analysed, focusing on disease frequency, patient characteristics, place of infection, course of disease, treatment and differences between network-member countries. RESULTS: Within the surveillance period 4,801 cases of imported malaria were reported. 618 (12.9%) were attributed to P. vivax. European travellers and immigrants were the largest patient groups, but their proportion varied among the reporting countries. The main regions of infection in descending order were the Indian subcontinent, Indonesia, South America and Western and Eastern Africa, as a group accounting for more than 60% of the cases. Regular use of malaria chemoprophylaxis was reported by 118 patients. With 86 (inter-quartile range 41–158) versus 31 days (inter-quartile range 4–133) the median symptom onset was significantly delayed in patients with chemoprophylaxis (p < 0.0001). Common complaints were fever, headache, fatigue, and musculo-skeletal symptoms. All patients survived and severe clinical complications were rare. Hospitalization was provided for 60% and primaquine treatment administered to 83.8% of the patients, but frequencies varied strongly among reporting countries. CONCLUSIONS: TropNetEurop data can contribute to the harmonization of European treatment policies

    Photoelectron energy losses to thermal electrons

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    The photoelectron energy loss rate to the ambient electrons is discussed. It is shown that the conventional Butler and Buckingham expression has been incorrectly applied in photoelectron calculations. The appropriate energy loss rates are indicated. It is also shown that the geomagnetic field has little influence on the photoelectron energy loss rate.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33734/1/0000248.pd

    Theoretical N2 vibrational distribution in an aurora

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    The N2 vibrational distribution in an aurora is investigated. During the auroral bombardment the vibrational distribution is non-Boltzmann. The deviation from the Boltzmann distribution increases with increasing altitude. Above 200 km the loss rate of O+ due to the reaction O+ + N2 --&gt; NO+ + N is increased by a factor of 1.5 when allowance is made for the non-Boltzmann character of the N2 distribution. This increased loss rate persists for 1000-2000 sec after auroral bombardment commences.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33545/1/0000044.pd

    Uncertainty causes rounding : an experimental study

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    Rounding is a common phenomenon when subjects provide an answer to an open-ended question, both in experimental tasks and in survey responses. From a statistical perspective, rounding implies that the measured variable is a coarsened version of the underlying continuous target variable. Since the coarsening process is non-random, inference from rounded data is generally biased. Despite the potentially severe consequences of rounding, little is known about its causes. In this paper, we focus on subjects' uncertainty about the target variable as one potential cause for rounding behavior. We present a novel experimental method that induces uncertainty in a controlled way, thus providing causal evidence for the effect of subjects' uncertainty on the extent of rounding. Then, we specify and estimate a mixture model that relates uncertainty and rounding. The results suggest that an increase in the exogenous level of uncertainty translates into higher variance of the subjects' beliefs, which in turn results in more rounding
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