1,886 research outputs found

    Apollo experience report: Television system

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    The progress of the Apollo television systems from the early definition of requirements through the development and inflight use of color television hardware is presented. Television systems that have been used during the Apollo Program are discussed, beginning with a description of the specifications for each system. The document describes the technical approach taken for the development of each system and discusses the prototype and engineering hardware built to test the system itself and to perform the testing to verify compatibility with the spacecraft systems. Problems that occurred during the design and development phase are described. Finally, the flight hardware, operational characteristics, and performance during several Apollo missions are described, and specific recommendations for the remaining Apollo flights and future space missions are made

    Organizational Change

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    This chapter examines how organizational change principles may be applied to promote organizational greening and employee pro-environmental behaviour. Four key areas of change management are focused upon: organizational culture; leadership and change agents; employee engagement; and the differing forms that change may take. The role of each factor in supporting environmental change is discussed, together with relevant research evidence drawn from the corporate sustainability; WPEB; management and organizational change literatures. Socio-Technical Systems Thinking is offered as a guiding framework with which to approach the design and implementation of holistic organizational change. The chapter concludes by outlining a number of important research developments that are required to aid progression within this domain and key practical recommendations for enacting organizational change for environmental sustainability are offered

    Analytical and experimental determination of signal-to-noise ratio and figure of merit in three phase-contrast imaging techniques

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    International audienceWe present a theoretical and experimental comparison of three X-ray phase-contrast techniques: propagation-based imaging, analyzer-based imaging and grating interferometry. The signal-to-noise ratio and the figure of merit are quantitatively compared for the three techniques on the same phantoms and using the same X-ray source and detector. Principal dependencies of the signal upon the numerous acquisition parameters, the spatial resolution and X-ray energy are discussed in detail. The sensitivity of each technique, in terms of the smallest detectable phase shift, is also evaluated

    A continuous sampling scheme for edge illumination x-ray phase contrast imaging

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    We discuss an alternative acquisition scheme for edge illumination (EI) x-ray phase contrast imaging (XPCi) based on a continuous scan of the object, and compare its performance to that of a previously used scheme, which involved scanning the object in discrete steps rather than continuously. By simulating signals for both continuous and discrete methods under realistic experimental conditions, the e ect of the spatial sampling rate is analysed with respect to metrics such as image contrast and accuracy of the retrieved phase shift. Experimental results con rm the theoretical predictions. Despite being limited to a speci c example, the results indicate that continuous schemes present advantageous features compared to discrete ones. Not only can they be used to speed up the acquisition, but they also prove superior in terms of accurate phase retrieval. The theory and experimental results provided in this study will guide the design of future EI experiments through the implementation of optimised acquisition schemes and sampling rates

    Comorbidades associadas às epilepsias e cefaleias

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    Comorbidities are often associated with chronic neurological diseases, such as headache and epilepsy. OBJECTIVES: To identify comorbidities associated with epilepsy and headaches, and to determine possible drug interactions. METHODS: A standardized questionnaire with information about type of epilepsy/headache, medical history, and medication was administered to 80 adult subjects (40 with epilepsy and 40 with chronic headache). RESULTS: Patients with epilepsy had an average of two comorbidities and those with headache of three. For both groups, hypertension was the most prevalent. On average, patients with epilepsy were taking two antiepileptic medications and those with headache were taking only one prophylactic medication. Regarding concomitant medications, patients with epilepsy were in use, on average, of one drug and patients with headache of two. CONCLUSIONS: Patients with chronic neurological diseases, such as epilepsy and headaches, have a high number of comorbidities and they use many medications. This may contribute to poor adherence and interactions between different medications.As comorbidades geralmente estão associadas a doenças neurológicas crônicas, tais como cefaleia e epilepsia. OBJETIVOS: Identificar comorbidades associadas à epilepsia e cefaleia e determinar as possíveis interações de drogas. MÉTODOS: Questionário padronizado com informações sobre o tipo de epilepsia/cefaleia, os antecedentes médicos e as medicações foi aplicado a 80 indivíduos adultos (40 com epilepsia e 40 com cefaleia crônica). RESULTADOS: Pacientes com epilepsia e cefaleia apresentaram uma média de duas e três comorbidades, respectivamente, sendo, para ambos, hipertensão arterial sistêmica a mais prevalente. Em média, os pacientes com epilepsia estavam em uso de duas medicações antiepilépticas; aqueles com cefaleia, uma medicação profilática. Em relação às medicações concomitantes, os pacientes com epilepsia estavam em uso, em média, de uma droga e os pacientes com cefaleia de duas. CONCLUSÕES: Pacientes com doenças neurológicas crônicas, como epilepsia e cefaleia, apresentam elevado número de comorbidades e utilizam grande número de medicações. Isso pode contribuir para diminuir a aderência ao tratamento e facilitar interações entre diversas medicações.27427

    Sponsored messaging about climate change on Facebook: Actors, content, frames

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    Online communication about climate change is central to public discourse around this contested issue. Facebook is a dominant social media platform known to be a major source of information and online influence, yet discussion of climate change on the platform has remained largely unstudied due to difficulties in accessing data. This paper utilises Facebook's repository of social/political ads to study how climate change is framed as an issue in adverts placed by different actors. Sponsored content is a strategic investment and presumably intended to be persuasive, so patterns of who pays for adverts and how those adverts frame the issue can reveal large-scale trends in public discourse. We show that most money spent on climate-related messaging is targeted at users in the US, GB and CA. While the number of advert impressions correlates with total spend by an actor, there is a secondary effect of unpaid social sharing which can substantially affect the number of impressions per dollar spent. Most spend in the US is by political actors, while environmental non-governmental organisations dominate spend in GB. Analysis shows that climate change solutions are well represented in GB, while climate change impacts such as extreme weather events are strongly represented in the US and CA. Different actor types frame the issue of climate change in different ways; political actors position the issue as party political and a point of difference between candidates, whereas environmental NGOs frame climate change as the focus of collective action and social mobilisation. Overall, our study provides a first empirical exploration of climate-related advertising on Facebook. It shows the diversity of actors seeking to use Facebook as a platform for their campaigns and how they utilise different topic frames to persuade users to act.Comment: 44 pages, 9 figure

    Using Intervention Mapping to Develop an Efficacious Multicomponent Systems-Based Intervention to Increase Human Papillomavirus (HPV) Vaccination in a Large Urban Pediatric Clinic Network

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    Background: The CDC recommends HPV vaccine for all adolescents to prevent cervical, anal, oropharyngeal, vaginal, vulvar, and penile cancers, and genital warts. HPV vaccine rates currently fall short of national vaccination goals. Despite evidence-based strategies with demonstrated efficacy to increase HPV vaccination rates, adoption and implementation of these strategies within clinics is lacking. The Adolescent Vaccination Program (AVP) is a multicomponent systems-based intervention designed to implement five evidence-based strategies within primary care pediatric practices. The AVP has demonstrated efficacy in increasing HPV vaccine initiation and completion among adolescents 10-17 years of age. The purpose of this paper is to describe the application of Intervention Mapping (IM) toward the development, implementation, and formative evaluation of the clinic-based AVP prototype. Methods: Intervention Mapping (IM) guided the development of the Adolescent Vaccination Program (AVP). Deliverables comprised: a logic model of the problem (IM Step 1); matrices of behavior change objectives (IM Step 2); a program planning document comprising scope, sequence, theory-based methods, and practical strategies (IM Step 3); functional AVP component prototypes (IM Step 4); and plans for implementation (IM Step 5) and evaluation (IM Step 6). Results: The AVP consists of six evidence-based strategies implemented in a successful sequenced roll-out that (1) established immunization champions in each clinic, (2) disseminated provider assessment and feedback reports with data-informed vaccination goals, (3) provided continued medical and nursing education (with ethics credit) on HPV, HPV vaccination, message bundling, and responding to parent hesitancy, (4) electronic health record cues to providers on patient eligibility, and (5) patient reminders for HPV vaccine initiation and completion. Conclusions: IM provided a logical and systematic approach to developing and evaluating a multicomponent systems-based intervention to increase HPV vaccination rates among adolescents in pediatric clinics

    Theoretical comparison of three X-ray phase-contrast imaging techniques: propagation-based imaging, analyzer-based imaging and grating interferometry

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    Various X-ray phase-contrast imaging techniques have been developed and applied over the last twenty years in different domains, such as material sciences, biology and medicine. However, no comprehensive inter-comparison exists in the literature. We present here a theoretical study that compares three among the most used techniques: propagation-based imaging (PBI), analyzer-based imaging (ABI) and grating interferometry (GI). These techniques are evaluated in terms of signal-to-noise ratio, figure of merit and spatial resolution. Both area and edge signals are considered. Dependences upon the object properties (absorption, phase shift) and the experimental acquisition parameters (energy, system point-spread function etc.) are derived and discussed. The results obtained from this analysis can be used as the reference for determining the most suitable technique for a given application
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