323 research outputs found

    Temporal Evolution of the Vela Pulsar's Pulse Profile

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    The mechanisms of emission and changes in rotation frequency ('glitching') of the Vela pulsar (J0835-4510) are not well understood. Further insight into these mechanisms can be achieved by long-term studies of integrated pulse width, timing residuals, and bright pulse rates. We have undertaken an intensive observing campaign of Vela and collected over 6000 hours of single pulse data. The data shows that the pulse width changes with time, including marked jumps in width after micro-glitches (frequency changes). The abundance of bright pulses also changes after some micro-glitches, but not all. The secular changes in pulse width have three possible cyclic periods, that match with X-ray periodicities of a helical jet that are interpreted as free precession.Comment: 6 pages, 8 figures. Accepted for publication in The Astrophysical Journa

    Modeling biochemical transformation processes and information processing with Narrator

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    BACKGROUND: Software tools that model and simulate the dynamics of biological processes and systems are becoming increasingly important. Some of these tools offer sophisticated graphical user interfaces (GUIs), which greatly enhance their acceptance by users. Such GUIs are based on symbolic or graphical notations used to describe, interact and communicate the developed models. Typically, these graphical notations are geared towards conventional biochemical pathway diagrams. They permit the user to represent the transport and transformation of chemical species and to define inhibitory and stimulatory dependencies. A critical weakness of existing tools is their lack of supporting an integrative representation of transport, transformation as well as biological information processing. RESULTS: Narrator is a software tool facilitating the development and simulation of biological systems as Co-dependence models. The Co-dependence Methodology complements the representation of species transport and transformation together with an explicit mechanism to express biological information processing. Thus, Co-dependence models explicitly capture, for instance, signal processing structures and the influence of exogenous factors or events affecting certain parts of a biological system or process. This combined set of features provides the system biologist with a powerful tool to describe and explore the dynamics of life phenomena. Narrator's GUI is based on an expressive graphical notation which forms an integral part of the Co-dependence Methodology. Behind the user-friendly GUI, Narrator hides a flexible feature which makes it relatively easy to map models defined via the graphical notation to mathematical formalisms and languages such as ordinary differential equations, the Systems Biology Markup Language or Gillespie's direct method. This powerful feature facilitates reuse, interoperability and conceptual model development. CONCLUSION: Narrator is a flexible and intuitive systems biology tool. It is specifically intended for users aiming to construct and simulate dynamic models of biology without recourse to extensive mathematical detail. Its design facilitates mappings to different formal languages and frameworks. The combined set of features makes Narrator unique among tools of its kind. Narrator is implemented as Java software program and available as open-source from

    Social Media Adoption in Adult Education ? Administrators' Experience

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    The rapid development of social media poses a multitude of considerations on this technology adoption. The emphasis in literature is put mainly on student or teacher perspective and less emphasis is dedicated upon administrators who also represent an important group of stakeholders. The aim of the study is to examine the phenomenon of potential educational use of social media at the public institutions of adult education based on administrators’ lived experience, taking into account how administrative factor influences social media adoption in education. The findings reveal that admitting the advantages of social media use, administrators also identify certain problematic areas and have cautious attitudes towards social media in education

    Hyperbolic limit on the early arrival time of bright pulses from PSR~J0835−-4510 (Vela)

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    Astronomers have studied the Vela pulsar (PSR~J0835−-4510) for decades. This study analyses almost one hundred hours of single-pulse data collected over three consecutive days from 2016 and 2020. The work investigates the fascinating phenomena of the earlier arrival of brighter pulses with their increase in peak intensity. We found a hyperbolic relation between them by constructing integrated pulse profiles using flux density intervals and examining the relationship between pulse arrival time and intensity. We identified a phase limit of −0.85 ±0.0109-0.85~\pm 0.0109~ms for the earliest arrival of the brightest pulses. This study offers exciting prospects for further exploring the emission regions responsible for the Vela pulsar's regular and giant micro-pulses.Comment: 9 pages, 11 figure

    Family mealtime emotions and food parenting practices among mothers of young children : development of the Mealtime Emotions Measure for Parents (MEM‐P)

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    Family mealtimes can be important for supporting children's healthy development, yet the emotional context of mealtimes can vary considerably, likely impacting their overall success and enjoyment. Yet, despite having an important role, little is known about how parents emotionally experience mealtimes with their family. The first aim of the current study was to assess the factor structure of a novel self‐report measure to assess parents’ emotional responses experienced during family mealtimes (Mealtime Emotions Measure for Parents; MEM‐P). The second aim was to examine relationships between maternal mealtime emotions and their food parenting practices. Mothers of children aged between 1.5 and 6 years participated in this study. Mothers were invited to complete an online questionnaire measuring family mealtime emotions, anxiety, depression and food parenting practices. Exploratory factor analysis produced a three‐factor solution comprising both positive and negative emotion subscales: MEM‐P Efficacy; MEM‐P Anxiety; MEM‐P Stress and Anger. Mothers' positive mealtime emotions (mealtime efficacy) were related to greater use of practices promoting autonomy, providing a healthy home food environment, and modelling healthy eating. Higher anxiety about mealtimes was related to greater reports of child control over eating, and mealtime stress and anger was associated with greater use of food to regulate emotions. These findings highlight novel relationships between how mothers emotionally experience family mealtimes and the food parenting practices they use with their children. It is important to develop resources to help promote positive maternal experiences of family mealtimes and food‐based interactions

    Developing a questionnaire to determine the impact of self-management in diabetes: giving people with diabetes a voice

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    Background The prevalence of diabetes mellitus (DM) is increasing dramatically, placing considerable financial burden on the healthcare budget of each country. Patient self-management is crucial for the control of blood glucose, which largely determines the chances of developing diabetes-related complications. Self-management interventions vary widely, and a method is required for assessing the impact of self-management. This paper describes the development of a questionnaire intended for use to measure the impact of self-management in diabetes. Methods An iterative development process was undertaken to identify the attributes of self-management using 5 steps. First, a literature review was undertaken to identify and understand themes relating to self-management of DM to inform a topic guide. Second, the topic guide was further refined following consultation with a Patient and Public Involvement group. Third, the topic guide was used to inform semi-structured interviews with patients with Type 1 DM (T1DM) and Type 2 DM (T2DM) to identify how self-management of DM affects individuals. Fourth, the research team considered potential attributes alongside health attributes from an existing measure (Diabetes Health Profile, DHP) to produce an instrument reflecting both health and self-management outcomes simultaneously. Finally, a draft instrument was tested in a focus group to determine the wording and acceptability. Results Semi-structured interviews were carried out with 32 patients with T1DM and T2DM. Eight potential attributes were identified: fear/worry/anxiety, guilt, stress, stigma, hassle, control, freedom, and feeling supported. Four of these self-management attributes were selected with four health attributes (mood, worry about hypos (hypoglycaemic episodes), vitality and social limitations) to produce the Health and Self-Management in Diabetes (HASMID v1) questionnaire. Conclusions HASMID v1 is a short questionnaire that contains eight items each with four response levels to measure the impact of self-management in diabetes for both T1DM and T2DM. The measure was developed using a mixed-methods approach that involved semi-structured interviews with people with diabetes. The measure has high face validity. Ongoing research is being undertaken to assess the validity of this questionnaire for measuring the impact of self-management interventions in economic evaluation

    Characterization of a radial turbocharger turbine in pulsating flow by means of CFD and its application to engine modeling

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    This paper presents a numerical study analyzing the effect of pulsating flow in a variable geometry radial inflow turbine. The turbine behavior is analyzed under isentropic pulses, which are similar to those created by a rotating disk in a turbocharger test rig. Three different pulse frequencies (50, 90 and 130 Hz) and two pulse amplitudes (100 and 180 kPa) were considered. Turbine flow was studied throughout the pressure pulsation cycles in a wide range of off-design operating conditions, from low pressure ratio flow detachment to high pressure ratio choked flow. An overall analysis of the phasing of instantaneous mass flow and pressure ratio was first performed and the results show the non-quasi-steady behavior of the turbine as a whole as described in the literature. However, the analysis of the flow in the different turbine components independently gives a different picture. As the turbine volute has greater length and volume than the other components, it is the main source of non-quasi-steadiness of the turbine. The stator nozzles cause fewer accumulation effects than the volute, but present a small degree of hysteretic behavior due to flow separation and reattachment cycle around the vanes. Finally, the flow in the moving rotor behaves as quasi-steady, as far as flow capacity is concerned, although the momentum transfer between exhaust gas and blades (and thus work production and thermal efficiency) is affected by a hysteretic cycle against pressure ratio, but not if blade speed ratio is considered instead. A simple model to simulate the turbine stator and rotor is proposed, based on the results obtained from the CFD computations.The authors are indebted to the Spanish Ministerio de Economia y Competitividad through Project TRA 2010-16205. The proof-reading of the paper was funded by the Universitat Politecnica de Valencia, Spain.Galindo, J.; Fajardo, P.; Navarro GarcĂ­a, R.; GarcĂ­a-Cuevas GonzĂĄlez, LM. (2013). Characterization of a radial turbocharger turbine in pulsating flow by means of CFD and its application to engine modeling. Applied Energy. 103:116-127. https://doi.org/10.1016/j.apenergy.2012.09.013S11612710

    Prescribing for the management of venous leg ulceration

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    Venous leg ulceration affects a large proportion of the elderly population and can have a profound impact on quality of life. Most patients with leg ulcers receive care from community nurses who are principally responsible for prescribing decisions in the management of venous leg ulceration. There is evidence to support the use of potable tap water for cleansing. Evidence supports the use of compression bandaging or compression hosiery for all patients with adequate arterial supply to the lower leg. There is also good evidence to support the prescription of oral pentoxifylline, preferably as an adjunct to compression or, for patients unable to tolerate compression, as a stand-alone therapy. The evidence base for dressings is less robust, but simple low-cost, low-adherent dressings are a reasonable first-line choice for under-compression

    Patient reported out come measures in patients with abdominal a ortic a neurysms: a systematic review p rotocol

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    Background: Abdominal aortic aneurysm (AAA) is a dilatation of the abdominal aorta, which is usually asymptomatic. However, rupture of the aneurysm can be fatal or require complex surgery with potential complications, leading to a poor quality of life. Patient reported outcome measures (PROMs) are becoming increasing ly important in the current era of healthcare management. PROMs are used to directly assess how patients feel or function in relation to their health condition without any interpretation . Generic, disease - specific and preference - based PROMs ca n be used to assess the quality of life (QoL), symptoms and functional limitations in patients with AAA including those under surveillance or undergoing endovascular or open surgery or screening . However, these tools vary in terms of their reliability, validity and suitability for use in patients with AAA in a clinical setting. Objectives: To identify, summarise and assess PROMs that have been administered to patients with a diagnosis of AAA including those under surveillance or undergoing endovascular or open surgery or screening . Methods: Key electronic databases and research registers will be searched including: MEDLINE and MEDLINE in Process, EMBASE, PsycINFO, PROQOLID, CINAH L, PROMS Bibliography (Oxford University), Web of Science and the Cochrane Library databases from inception. A two - stage search approach will be used. The first stage will utilise general terms for PROMs to identify studies. These will be retrieved and t he title and abstract will be examined for additional PROM terms. Stage 2 will incorporate these terms with the preliminary search strategy and a methodological search filter . Searches will be supplemented by hand - searching reference lists of relevant reviews and included studies. Study selection, data extraction and quality assessment will be performed independently by at least 2 reviewers. All English language instruments identified as PROMs for patients with AAA will be included. Data will be extracted regarding type of PROM, methods and results. Methodological quality of included studies will be assessed using the CO nsensus - based S tandards for the selection of health st atus Measurement IN struments checklist (COSMIN) and the psychometric properties of the PROMs will be assessed on criteria bas ed in published recommendations. Findings will be presented as narrative and tabular summaries. Discussion : This systematic review will identify PROMs that are used to assess QoL , symptoms and functional limitations in patients with AAA and assess their effectiveness for this population and application to clinical practice. The findings of the review will help inform a project examining the re-configuration of vascular services in the UK, and identify targets for future research

    Patient-reported outcome measures in patients with peripheral artery disease: Protocol for a systematic review

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    Peripheral arterial disease (PAD) results in reduced health-related quality of life and significant functional impairment. Patient-reported outcome measures (PROMs) are important when considering the impact of treatments and management strategies in patients with PAD. A variety of studies have reported the use of different PROMs in patients with PAD. However, PROMs should provide valid and reliable findings to help in healthcare decision-making. The aim of this proposed systematic review is to comprehensively evaluate the psychometric properties of PROMs developed and/ or validated in patients with PAD
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