872 research outputs found

    A tabulation of pipe length to diameter ratios as a function of Mach number and pressure ratios for compressible flow

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    Computer programs and resulting tabulations are presented of pipeline length-to-diameter ratios as a function of Mach number and pressure ratios for compressible flow. The tabulations are applicable to air, nitrogen, oxygen, and hydrogen for compressible isothermal flow with friction and compressible adiabatic flow with friction. Also included are equations for the determination of weight flow. The tabulations presented cover a wider range of Mach numbers for choked, adiabatic flow than available from commonly used engineering literature. Additional information presented, but which is not available from this literature, is unchoked, adiabatic flow over a wide range of Mach numbers, and choked and unchoked, isothermal flow for a wide range of Mach numbers

    Runtime Verification of Temporal Properties over Out-of-order Data Streams

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    We present a monitoring approach for verifying systems at runtime. Our approach targets systems whose components communicate with the monitors over unreliable channels, where messages can be delayed or lost. In contrast to prior works, whose property specification languages are limited to propositional temporal logics, our approach handles an extension of the real-time logic MTL with freeze quantifiers for reasoning about data values. We present its underlying theory based on a new three-valued semantics that is well suited to soundly and completely reason online about event streams in the presence of message delay or loss. We also evaluate our approach experimentally. Our prototype implementation processes hundreds of events per second in settings where messages are received out of order.Comment: long version of the CAV 2017 pape

    The lived experience of dysphagia following non-surgical treatment for head and neck cancer

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    The prevalence and severity of dysphagia in people treated non-surgically for primary head and neck cancer (HNC) is well documented. However, few studies have looked beyond the physiological impairment to explore the lived experience of dysphagia in the post-treatment period of HNC. The current study adopted a person-centred, qualitative approach to describe the experiences of people living with dysphagia in the months and years following non-surgical treatment for HNC. Using maximum variation sampling, 24 participants who had undergone radiotherapy treatment for HNC were recruited. Individual interviews were conducted to explore the impact of dysphagia on participants' everyday lives. The themes identified included: (1) physical changes related to swallowing; (2) emotions evoked by living with dysphagia; (3) altered perceptions and changes in appreciation of food; and (4) personal and lifestyle impacts. The data revealed the breadth and significance of the impact of dysphagia on the lives of people treated curatively for HNC. Assessment and management in the post-treatment period must be sufficiently holistic to address both the changing physical states and the psychosocial needs of people with dysphagia following HNC. Rehabilitation services which focus only on impairment-based management will fail to fully meet the support needs of this clinical population

    Fatty Acid Blood Levels, Vitamin D Status, and Physical Performance and Its Relationship to Resiliency and Mood in Active Duty Soldiers

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    The mental health of soldiers is a growing concern as rates of depression and suicide have increased in soldiers with recently more deaths attributed to suicide than deaths due to combat in Afghanistan in 2012. Previous research has demonstrated the potential for eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), vitamin D, physical activity, and physical fitness to improve and arachidonic acid (AA) to threaten depression/quality of life scores. This study examined whether blood fatty acid levels, vitamin D status and/or physical activity are associated with physical fitness scores, measures of mood, and measures of resiliency in active duty soldiers. 100 active duty males at Fort Hood, TX underwent a battery of psychometric tests, anthropometric, fitness tests, and donated fasting blood samples. Pearson bivariate correlation analysis revealed significant correlations among psychometric tests, anthropometric, physical performance, reported physical inactivity (sitting time), and fatty acid and vitamin D blood levels. Categorical analysis revealed significant difference in levels of fatty acids and vitamin D, anthropometric, physical performance, and psychometric measures. Based on these findings, a regression equation was developed to predict a depressed mood status as determined by the Patient Health Questionnaire-9. The equation accurately predicted 80% of our participants with a sensitivity of 76.9% and a specificity of 80.5%. Results indicate that lack of physical activity and fitness, high levels of AA and low levels of EPA, DHA, and vitamin D could increase the risk of depressed mood and that use of a regression equation may be helpful in identifying soldiers at higher risk for possible intervention. Future studies should evaluate the impact of exercise and diet interventions as a means of improving resiliency and reducing depressed mood in soldiers

    Attitudes of Secondary Teachers toward Mainstreaming Mildly Educationally Handicapped Students

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    With the enactment of Public Law 94-142, the Education For All Handicapped Children Act of 1975, while most educators have been influenced by the requirement to meet the needs of youngsters in the least restrictive environment, onus of responsibility generally filters down to the classroom teachers. It was the purpose of this study to determine just what are the attitudes of secondary teachers toward integrating the mildly educationally handicapped student into the regular class. The primary question was whether exposure to the concept of mainstreaming positively influences attitudes. The investigation involved 501 secondary teachers selected by a stratified random sampling from across the state of Iowa. They were classified into three teaching groups: regular class, special class and special education. From each category, 167 were then randomly selected in order to equally represent each teaching category. Instrumentation was accomplished through a questionnaire which solicited educator response to 20 items relating to the integration of mildly educationally handicapped students into the secondary classroom. Analysis of variance results were obtained. Conclusions of the study, as taken from the selected population, indicated that attitudes were significantly associated positively with teacher assignment (special education), prior contact (yes), perceived adequacy of training (adequate) and gender of the teacher (female). Degree held, years of teaching experience and community service(d) affected attitudes only insofar as they were mediated by the four more dominant factors. When all independent variables were paired with each other in 21 conditions, no instance of significant interaction effects were discovered. All independent variables were found to be operating independently of each other in their relationship to receptivity scores

    A foundation for runtime monitoring

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    Runtime Verification is a lightweight technique that complements other verification methods in an effort to ensure software correctness. The technique poses novel questions to software engineers: it is not easy to identify which specifications are amenable to runtime monitor-ing, nor is it clear which monitors effect the required runtime analysis correctly. This exposition targets a foundational understanding of these questions. Particularly, it considers an expressive specification logic (a syntactic variant of the modal μ-calculus) that is agnostic of the verification method used, together with an elemental framework providing an operational semantics for the runtime analysis performed by monitors. The correspondence between the property satisfactions in the logic on the one hand, and the verdicts reached by the monitors performing the analysis on the other, is a central theme of the study. Such a correspondence underpins the concept of monitorability, used to identify the subsets of the logic that can be adequately monitored for by RV. Another theme of the study is that of understanding what should be expected of a monitor in order for the verification process to be correct. We show how the monitor framework considered can constitute a basis whereby various notions of monitor correctness may be defined and investigated.peer-reviewe

    From Parametric Trace Slicing to Rule Systems

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    Parametric runtime verification is the process of verifying properties of execution traces of (data carrying) events produced by a running system. This paper continues our work exploring the relationship between specification techniques for parametric runtime verification. Here we consider the correspondence between trace-slicing automata-based approaches and rule-systems. The main contribution is a translation from quantified automata to rule-systems, which has been implemented in Scala. This then allows us to highlight the key differences in how the two formalisms handle data, an important step in our wider effort to understand the correspondence between different specification languages for parametric runtime verification

    Non-solvolytic synthesis of aqueous soluble TiO2 nanoparticles and real-time dynamic measurements of the nanoparticle formation.

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    Highly aqueously dispersible (soluble) TiO2 nanoparticles are usually synthesized by a solution-based sol-gel (solvolysis/condensation) process, and no direct precipitation of titania has been reported. This paper proposes a new approach to synthesize stable TiO2 nanoparticles by a non-solvolytic method - direct liquid phase precipitation at room temperature. Ligand-capped TiO2 nanoparticles are more readily solubilized compared to uncapped TiO2 nanoparticles, and these capped materials show distinct optical absorbance/emission behaviors. The influence of ligands, way of reactant feeding, and post-treatment on the shape, size, crystalline structure, and surface chemistry of the TiO2 nanoparticles has been thoroughly investigated by the combined use of X-ray diffraction, transmission electron microscopy, UV-visible (UV-vis) spectroscopy, and photoluminescence (PL). It is found that all above variables have significant effects on the size, shape, and dispersivity of the final TiO2 nanoparticles. For the first time, real-time UV-vis spectroscopy and PL are used to dynamically detect the formation and growth of TiO2 nanoparticles in solution. These real-time measurements show that the precipitation process begins to nucleate after an initial inhibition period of about 1 h, thereafter a particle growth occurs and reaches the maximum point after 2 h. The synthesis reaction is essentially completed after 4 h.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

    Fair game: exploring the dynamics, perception and environmental impact of ‘surplus’ wild foods in England 10kya-present

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    This paper brings together zooarchaeological data from Neolithic to Post-medieval sites in England to explore the plasticity of cultural attitudes to the consumption of wild animals. It shows how, through time, game has been considered variously as ‘tabooed’ and ‘edible’, each having implications for patterns of biodiversity and wildlife management. The essential points being made are that deeper-time studies can reveal how human perceptions of ‘surplus foods’ have the potential to both create and remedy problems of environmental sustainability and food security. Perhaps more significantly, this paper argues that understanding the bio-cultural past of edible wild animal species has the potential to transform human attitudes to game in the present. This is important at a time when food security and the production of surplus are pressing national and global concerns

    The international entrepreneurial firm's social networks

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    This paper investigates theoretically the importance and impact of the international entrepreneurial firms’ (IEFs) social networks on selected firms’ strategies. We focus specifically on some core attributes of IEFs and the impact of social networks on such strategies as the choice of the foreign markets to operate and the foreign entry modes. The social networks are a major driver of the internationalization from inception and help in overcoming a variety of physical and social resource limitations as well as transactional hazards. We conclude that it is likely that both some fundamental characteristics of the IEFs and those of the foreign markets entered account for these firms reliance on their social networks
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