17,975 research outputs found

    The effects of high energy particles on planetary missions

    Get PDF
    Researchers review the background and motivation for the detailed study of the variability and uncertainty of the particle environment from a space systems planning perspective. The engineering concern raised by each environment is emphasized rather than the underlying physics of the magnetosphere or the sun. Missions now being planned span the short term range of one to three years to periods over ten years. Thus the engineering interest is beginning to stretch over periods of several solar cycles. Coincidentally, detailed measurements of the environment are now becoming available over that period of time. Both short term and long term environmental predictions are needed for proper mission planning. Short term predictions, perhaps based on solar indices, real time observations, or short term systematics, are very useful in near term planning -- launches, EVAs (extravehicular activities), coordinated observations, and experiments which require the magnetosphere to be in a certain state. Long term predictions of both average and extreme conditions are essential to mission design. Engineering considerations are many times driven by the worst case environment. Knowledge of the average conditions and their variability allows trade-off studies to be made, implementation of designs which degrade gracefully under multi-stress environments

    Unit Root Testing in a Central Bank

    Get PDF
    Central bank economists have to understand and forecast macroeconomic time series. A serious problem that they face is that those series are often trended or a.ected by persistent innovations to the process. To try to get round this problem, or at least to understand its possible e.ects, it is common to test whether series are stationary. These tests are often called unit-root tests.1 In this handbook we discuss such testing. A model-builder should use appropriate econometric techniques. In order to choose between alternative estimators, the model-builder needs to think carefully about the relevant theory and the available data. But economic theory is rarely unambiguous in its implications for the data generating process. Subjecting the data to pre-estimation testing can help to gauge the relevance of different theories and possible data problems.Unit, Root, Testing, Central Bank

    'It'll get worse before it gets better': Local experiences of living in a regeneration area

    Get PDF
    The negative consequences of living in deprived neighbourhoods for residents’ quality of life are well documented. Area-based regeneration initiatives are invariably concerned with improving local quality of life over the long term. The process of regeneration, however, can itself directly result in immediate and potentially lasting negative effects for local communities. This paper discusses some of the ways in which living in an area undergoing regeneration can adversely affect inhabitants’ quality of life, including problems associated with voids, relocation, demolitions, environmental quality, complexity, funding issues, uncertainty, frustration, fear for the future and consultation fatigue. A case study approach draws examples from a deprived neighbourhood in the North East of England. The conclusion discusses some of the possible implications for future regeneration policy, including: the importance of ongoing communication between professionals and communities; the need to value local people’s experience, judgement and the contribution they can make to local decision-making processes; recognition that successful regeneration can take many years; and the implications of current UK government policy

    "I Ain't No Tea Lady": Identifying and addressing barriers to non-traditional employment, training and education from a female perspective, SOVA

    Get PDF
    The aim of this research was to examine perceptions and experiences of accessing non-traditional Education Training and Employment (ETE) from the vantage point of disadvantaged women using innovative sampling and research techniques. The research design and strategy sought to access the participant’s views and valuable experience. Many of the women whose opinions the research was trying to elicit had never considered non-traditional ETE, in their own words it simply was 'not on their radar'. We decided to adopt a 'workshop' approach. A workshop format was designed which used fun and thought provoking exercises to promote discussion. These interactive and dynamic workshops proved successful in generating some excellent data. In total 80 women from a range of areas of disadvantage participated in the research

    Sport-Related Injuries in Canadian Interuniversity Athletics: A Descriptive Epidemiologic Analysis of Knee Injuries, 2014-2017

    Get PDF
    The purpose of this study was to identify and establish the extent of sport-related injury in Canadian university varsity athletics, focusing on knee injury and significant sport injury. Of the SRIs reported, 20% were significant in nature and 23.2% were knee injuries. A larger percentage of knee SRIs were significant compared non-knee SRIs. Those suffering a knee injury were 4.5 times more likely to suffer a significant injury than those afflicted with non-knee injuries. Mens volleyball athletes are two times more likely to suffer a knee injury, once controlled for sport group. Once controlled for sport, mens hockey athletes are 2.3 times more likely to suffer a significant injury than any other sport (Table 4). Mens basketball has the highest rate of injury (3.32 per athlete) during this reporting period and football has the highest rate of significant knee injury at 0.27 per athlete (Table 1)

    Lifetime Adherence to Physical Activity Recommendations and Fall Occurrence in Community-dwelling Older Adults: a Retrospective Cohort Study

    Get PDF
    Falling is a major health concern for community-dwelling older adults. Regular physical activity has been proposed to prevent falls. The aim of this study was to assess whether the achievement of the 2004 UK Department of Health physical activity recommendations over a lifetime had a protective effect against falling in older people. 313 community-dwelling older adults completed a questionnaire about lifetime physical activity and fall occurrence. There were significantly fewer falls in those who had led an active lifestyle compared to those who had not (χ2Yates=4.568, p=0.033), with a lower relative risk of fall occurrence for the active respondents (RR=0.671) compared to the inactive (RR=1.210). Of those who were sufficiently active in their early adulthood, the decade where there was the biggest decrease in remaining active enough was in the 60s. It is concluded that an active lifestyle may have decreased the likelihood of having a fall in older ag

    Comment on "Large Difference in the Elastic Properties of fcc and hcp Hard-Sphere Crystals"

    Get PDF
    As is well known, hard-sphere crystals of the fcc and hcp type differ very little in their thermodynamic properties. Nonetheless, recent computer simulations by Pronk and Frenkel indicate that the elastic response to mechanical deformation of the two types of crystal should be quite different. By invoking a geometrical argument put forward by R. Martin some time ago, we suggest that this is largely due to the different symmetries of the fcc and hcp crystal structures. Indeed, we find that elastic constants obtained by means of computer simulations for the fcc hard-sphere crystal can be mapped onto the equivalent ones of the hcp crystal to very high accuracy. The same procedure applied to density functional theoretical predictions for the elastic properties of the fcc hard-sphere crystal also produces remarkably accurate predictions for those of the hcp hard-sphere crystal.Comment: 7 pages, 5 figure

    BiofilmQuant: A Computer-Assisted Tool for Dental Biofilm Quantification

    Full text link
    Dental biofilm is the deposition of microbial material over a tooth substratum. Several methods have recently been reported in the literature for biofilm quantification; however, at best they provide a barely automated solution requiring significant input needed from the human expert. On the contrary, state-of-the-art automatic biofilm methods fail to make their way into clinical practice because of the lack of effective mechanism to incorporate human input to handle praxis or misclassified regions. Manual delineation, the current gold standard, is time consuming and subject to expert bias. In this paper, we introduce a new semi-automated software tool, BiofilmQuant, for dental biofilm quantification in quantitative light-induced fluorescence (QLF) images. The software uses a robust statistical modeling approach to automatically segment the QLF image into three classes (background, biofilm, and tooth substratum) based on the training data. This initial segmentation has shown a high degree of consistency and precision on more than 200 test QLF dental scans. Further, the proposed software provides the clinicians full control to fix any misclassified areas using a single click. In addition, BiofilmQuant also provides a complete solution for the longitudinal quantitative analysis of biofilm of the full set of teeth, providing greater ease of usability.Comment: 4 pages, 4 figures, 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC 2014
    corecore