1,575 research outputs found

    Data acquisition system for NASA LaRC impact dynamics research facility

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    A data system is designed to permit the simultaneous recording of 90 data channels on one 28 track magnetic tape recorder using a constant bandwidth FM multiplexing technique. Dynamic signals from transducers located in the test aircraft are amplified and fed to voltage controlled oscillators where they are converted to discrete FM signals. The signals from each group of five VCO's are fed to a mixer/distribution amplifier where they are combined into one composite signal and recorded, using direct recording techniques, on one magnetic tape recorder track. Millivolt signals from the recorders reproduce heads are amplified to one volt and then electronically switched to an FM demultiplexing system where appropriate frequency discrimination and signal filtering recover the original analog information

    Variations in the spatial distribution of 11 Micron radiation from omicron Ceti

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    The spatial distribution of 11 micron radiation from omicron Ceti was observed at various phases of its light cycle using a stellar interferometer. Changes were seen which can be attributed to variation in the strength of thermal emission from circumstellar dust relative to the stellar continuum at 11 microns. These changes are shown to be correlated with the changes in luminosity of micron Ceti in such a way that dust grain emission at 11 microns was increased more than the continuum during the period of maximum luminosity. The degree of the change in dust grain emission implies that the maximum dust temperature is in the range of 500 K to 700 K during minimum stellar luminosity

    The brightness distribution of IRC +10216 at 11 microns

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    The brightness distribution of IRC +10216 at a wavelength of 11 microns was measured in detail using a spatial interferometer. This brightness distribution appears to have azimuthal symmetry; an upper limit of 1.1 may be set to the ellipticity at 11 microns if the object has a major axis oriented either along or perpendicular to the major axis of the optical image. The radial distribution shows both compact and extended emission. The extended component, which is due to thermal emission from circumstellar dust, contributes 91% of the total flux and has a 1/e diameter of 0.90 minutes. The tapered shape of this component is consistent with a l/r squared dust density dependence. The compact component is unresolved (less than 0.2 minutes in diameter) and represents emission from the central star seen through the circumstellar envelope

    Spatial heterodyne interferometry of VY Canis Major's, alpha Orionis, alpha Scorpii, and R leonis at 11 microns

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    Using the technique of heterodyne interferometry, measurements were made of the spatial distribution of 11 micron radiation from four late type stars. The circumstellar shells surrounding VY Canis Majoris, alpha Orionis, and alpha Scorpii were resolved, whereas that of R Leonis was only partially resolved at a fringe spacing of 0.4 sec

    Extracting Information from Adaptive Control Experiments

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    Optical control of chemical reactivity is achieved through the use of photonic reagents, that is, “shaped” ultrafast optical pulses created using a pulse shaper. It has been demonstrated in a number of molecular systems that these pulses can effectively guide the system into a desired final state. Effective pulses are often found through an experimental search involving thousands of individual measurements. An examination of the pulses tested in these experiments can reveal the pulse features responsible for control and also the underlying molecular dynamics. In this article we review attempts to extract information from optical control experiments using adaptive learning algorithms to search the available parameter space, and we discuss how these kinds of experiments can be used to achieve and understand multiphoton optical control.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91361/1/397_ftp.pd

    Reduction of the size of datasets by using evolutionary feature selection: the case of noise in a modern city

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    Smart city initiatives have emerged to mitigate the negative effects of a very fast growth of urban areas. Most of the population in our cities are exposed to high levels of noise that generate discomfort and different health problems. These issues may be mitigated by applying different smart cities solutions, some of them require high accurate noise information to provide the best quality of serve possible. In this study, we have designed a machine learning approach based on genetic algorithms to analyze noise data captured in the university campus. This method reduces the amount of data required to classify the noise by addressing a feature selection optimization problem. The experimental results have shown that our approach improved the accuracy in 20% (achieving an accuracy of 87% with a reduction of up to 85% on the original dataset).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This research has been partially funded by the Spanish MINECO and FEDER projects TIN2016-81766-REDT (http://cirti.es), and TIN2017-88213-R (http://6city.lcc.uma.es)

    Comparison between the for-profit human milk industry and nonprofit human milk banking: Time for regulation?

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    Human milk (HM) is a highly evolutionary selected, complex biofluid, which provides tailored nutrition, immune system support and developmental cues that are unique to each maternal-infant dyad. In the absence of maternal milk, the World Health Organisation recommends vulnerable infants should be fed with screened donor HM (DHM) from a HM bank (HMB) ideally embedded in local or regional lactation support services. However, demand for HM products has arisen from an increasing awareness of the developmental and health impacts of the early introduction of formula and a lack of prioritisation into government-funded and nonprofit milk banking and innovation. This survey of global nonprofit milk bank leaders aimed to outline the trends, commonalities and differences between nonprofit and for-profit HM banking, examine strategies regarding the marketing and placement of products to hospital and public customers and outline the key social, ethical and human rights concerns. The survey captured information from 59 milk bank leaders in 30 countries from every populated continent. In total, five companies are currently trading HM products with several early-stage private milk companies (PMCs). Products tended to be more expensive from PMC than HMB, milk providers were financially remunerated and lactation support for milk providers and recipients was not a core function of PMCs. Current regulatory frameworks for HM vary widely, with the majority of countries lacking any framework, and most others placing HM within food legislation, which does not include the support and care of milk donors and recipient prioritisation. Regulation as a Medical Product of Human Origin was only in place to prevent the sale of HM in four countries; export and import of HM was banned in two countries. This paper discusses the safety and ethical concerns raised by the commodification of HM and the opportunities policymakers have globally and country-level to limit the potential for exploitation and the undermining of breastfeeding

    When are anti-fat attitudes understood as prejudice versus truth? An experimental study of social influence effects

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    Background/Objectives If people who hold anti-fat attitudes believe these attitudes to be true, then anti-prejudice appeals are likely to be unsuccessful, if only because the targets will not see their attitudes as in need of change. The current study examined processes that may lead people to see their anti-fat attitudes as 'truth' or as 'prejudice'. Subjects/Methods Participants (N = 482) read anti-fat statements and were then presented with an interpretation of these statements as 'truth' or 'prejudice'. The source of this interpretation was either an (i) in-group or out-group member and (ii) expert or non-expert. Participants' judgements of the statements were expected to vary such that in-group others and experts would exert more influence than would out-group others and non-experts. Results Participants aligned their own interpretations of an anti-fat statement with those of an expert, but not with those of a non-expert, F(1,466) = 8.97, p <0.05, eta(2)(p) = 0.02. The group membership variable had no effect on judgements of 'truth' or 'prejudice' of the anti-fat statement. Conclusion The expressions that people believe constitute anti-fat prejudice versus truth about people described as overweight are influenced by exposure to expert opinion (in this case, by medical doctors). Implications for the success of weight-based anti-prejudice appeals and for healthcare provision are discussed

    Open defecation and childhood stunting in India: an ecological analysis of new data from 112 districts.

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    Poor sanitation remains a major public health concern linked to several important health outcomes; emerging evidence indicates a link to childhood stunting. In India over half of the population defecates in the open; the prevalence of stunting remains very high. Recently published data on levels of stunting in 112 districts of India provide an opportunity to explore the relationship between levels of open defecation and stunting within this population. We conducted an ecological regression analysis to assess the association between the prevalence of open defecation and stunting after adjustment for potential confounding factors. Data from the 2011 HUNGaMA survey was used for the outcome of interest, stunting; data from the 2011 Indian Census for the same districts was used for the exposure of interest, open defecation. After adjustment for various potential confounding factors--including socio-economic status, maternal education and calorie availability--a 10 percent increase in open defecation was associated with a 0.7 percentage point increase in both stunting and severe stunting. Differences in open defecation can statistically account for 35 to 55 percent of the average difference in stunting between districts identified as low-performing and high-performing in the HUNGaMA data. In addition, using a Monte Carlo simulation, we explored the effect on statistical power of the common practice of dichotomizing continuous height data into binary stunting indicators. Our simulation showed that dichotomization of height sacrifices statistical power, suggesting that our estimate of the association between open defecation and stunting may be a lower bound. Whilst our analysis is ecological and therefore vulnerable to residual confounding, these findings use the most recently collected large-scale data from India to add to a growing body of suggestive evidence for an effect of poor sanitation on human growth. New intervention studies, currently underway, may shed more light on this important issue

    When non-activists care: group efficacy mediates the effect of social identification and perceived instability on the legitimacy of collective action

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    In recent years, multiple social movements have emerged around the world. In addition, public surveys indicate the highest recorded levels of support for protest. In this context of acceptance of collective action, we examine the role of non-activists in the legitimacy of social movements, as this ‘passive’ support can contribute to social change. Given that antecedents of legitimacy have been neglected in the literature, we carried out a survey (N = 605) among a general sample of the population in Chile to shed light on this issue. We found that social identification with movements and perceived instability predicted the perceived legitimacy of protests by social movements, and that both variables had only indirect effects, through group efficacy. This suggests that perceiving social movements as able to achieve success can lead non-activists to perceive their actions as legitimate, highlighting the importance to movements of being seen to be effective
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