717 research outputs found

    Revised time-of-flight calculations for high-latitude geomagnetic pulsations using a realistic magnetospheric magnetic field model

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    We present a simple time-of-flight analysis of Alfvén pulsations standing on closed terrestrial magnetic field lines. The technique employed in this study in order to calculate the characteristic period of such oscillations builds upon earlier time-of-flight estimates via the implementation of a more recent magnetospheric magnetic field model. In this case the model employed is the Tsyganenko (1996) field model, which includes realistic magnetospheric currents and the consequences of the partial penetration of the interplanetary magnetic field into the dayside magnetopause. By employing a simple description of magnetospheric plasma density, we are therefore able to estimate the period of standing Alfvén waves on geomagnetic field lines over a significantly wider range of latitudes and magnetic local times than in previous studies. Furthermore, we investigate the influence of changing season and upstream interplanetary conditions upon the period of such pulsations. Finally, the eigenfrequencies of magnetic field lines computed by the time-of-flight technique are compared with corresponding numerical solutions to the wave equation and experimentally observed pulsations on geomagnetic field lines

    The representation of scientific research in the national curriculum and secondary school pupils’ perceptions of research, its function, usefulness and value to their lives

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    Young people’s views on what research is, how it is conducted and whether it is important, influences the decisions they make about their further studies and career choices. In this paper we report the analysis of questionnaire data with a particular focus on pupil perceptions of research in the sciences and of the scientific method. The questionnaire was a 25-item Likert Scale (1-5) distributed to seven collaborating schools. We received 2634 returns from pupils across key stages 3, 4 and 5. We also asked teachers to complete the questionnaire in order to explore how they thought their pupils would respond. We received 54 teacher responses. Statistically significant differences in the responses were identified through a chi-square test on SPSS. As what is being taught influences secondary pupil views on research we also consider how the term ‘research’ appears in the national curriculum for England and Wales and the three main English exam boards. The main theoretical construct that informs our analysis of the questionnaire data and the national curriculum is Angela Brew’s 4-tier descriptor of perceptions of research (domino, trading, layer, journey). We use this framework in order to map what, when and how research is presented to school pupils in England and Wales. We also use this framework in order to highlight and discuss certain pupil views that emerged from the questionnaire data and which indicate areas where curriculum and pedagogy intervention may be necessary: pupils seem less confident in their understanding of research as involving the identification of a research question; and, they often see research as a means to confirm one’s own opinion. They do however understand research as involving the generation of new knowledge and the collection of new data, such as interviews and questionnaires as well as laboratory work, field trips and library searches and they appear relatively confident in their statements about their ability to do research, their school experiences of research and the importance of research in their future career choice

    Cluster spacecraft observations of a ULF wave enhanced by Space Plasma Exploration by Active Radar (SPEAR)

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    Space Plasma Exploration by Active Radar (SPEAR) is a high-latitude ionospheric heating facility capable of exciting ULF waves on local magnetic field lines. We examine an interval from 1 February 2006 when SPEAR was transmitting a 1 Hz modulation signal with a 10 min on-off cycle. Ground magnetometer data indicated that SPEAR modulated currents in the local ionosphere at 1 Hz, and enhanced a natural field line resonance with a 10 min period. During this interval the Cluster spacecraft passed over the heater site. Signatures of the SPEAR-enhanced field line resonance were present in the magnetic field data measured by the magnetometer on-board Cluster-2. These are the first joint ground- and space-based detections of field line tagging by SPEAR

    Development and Evaluation of an Undergraduate Science Communication Module

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    This paper describes the design and evaluation of an undergraduate final year science communication module for the Science Faculty at the University of East Anglia. The module focuses specifically on science communication and aims to bring an understanding of how science is disseminated to the public. Students on the module are made aware of the models surrounding science communication and investigate how the science culture interfaces with the public. During the module they learn how to adapt science concepts for different audiences and how to talk confidently about science to a lay-audience. Student motivation for module choice centres on the acquisition of transferable skills and students develop these skills through designing, running and evaluating a public outreach event at a school or in a public area. These transferable skills acquired include communication, interaction with different organisations such as museums and science centres, developing understanding of both the needs of different audiences and the importance of time management. They also develop skills relating to self-reflection and how to use this as a tool for future self development. The majority of students completing the module go on to further study, either a PhD, MSc or teacher training. The module can be sustained in its present formed if capped at 40 students, however it is recognised that to increase cohort size, further investment of faculty time and resources would be required

    Observations and modelling of the wave mode evolution of an impulse-driven 3 mHz ULF wave

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    A combination of an HF Doppler sounder, a network of ground magnetometers, upstream solar wind monitors and a numerical model is used to examine the temporal evolution of an Ultra Low Frequency (ULF) wave. The event occurred on 16 April 1998 and followed a solar wind density and pressure increase seen in the upstream ACE spacecraft data. The magnetometer and HF Doppler sounder data show that the event develops into a low-<I>m</I> (&minus;6) field line resonance. HF signals that propagate via the ionosphere exhibit Doppler shifts due to a number of processes that give rise to a time-dependent phase path. The ULF electric and magnetic fields are calculated by a one-dimensional model which calculates the wave propagation from the magnetosphere, through the ionosphere to the ground with an oblique magnetic field. These values are then used to determine a model HF Doppler shift which is subsequently compared to HF Doppler observations. The ULF magnetic field at the ground and Doppler observations are then used to provide model inputs at various points throughout the event. We find evidence that the wave mode evolved from a mixture of fast and Alfvén modes at the beginning of the event to an almost purely shear Alfvénic mode after 6 wavecycles (33 min)

    Adverse Childhood Experiences and Adult Smoking, Nebraska, 2011

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    Introduction Smoking is a public health risk; the prevalence of smoking among adults in Nebraska is 18-4%. Studies indicate that maltreatment of children alters their brain development, possibly increasing risk for tobacco use. Previous studies have documented associations between childhood maltreatment and adult health behaviors, demonstrating the influence of adverse experiences on tobacco use. We examined prevalence and associations between adverse childhood experiences and smoking among Nebraskans. Methods We analyzed 2011 Nebraska Behavioral Risk Factor Surveillance System (Adverse Childhood Experience module) data, defining adverse childhood experience exposures as physical, sexual, and verbal abuse (ie, direct exposures), and household dysfunction associated with mental illness, substance abuse, divorce, domestic violence, and living with persons with incarceration histories (ie, environmental exposures). We estimated prevalence of exposures, taking into account the complex survey design. We used logistic regression with predicted margins to estimate adjusted relative risk for smoking by direct or environmental exposure. Results Approximately 51% of Nebraskans experienced 1 or more adverse childhood events; 7% experienced 5 or more. Prevalence of environmental exposures (42%) was significantly higher than that of direct exposures (31%). Prevalence of individual exposures ranged from 6% (incarceration of a household member) to 25% (verbal abuse). Adjusted relative risks of smoking for direct and environmental exposures were 1.5 and 1.8, respectively. Conclusion We present a new method of evaluating adverse childhood experience data. Prevalence of adverse childhood experiences is high among Nebraskans, and these exposures are associated with smoking. State-specific strategies to monitor adverse events among children and provide interventions might help to decrease the smoking rate in this population

    Adverse Childhood Experiences and Adult Smoking, Nebraska, 2011

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    Introduction Smoking is a public health risk; the prevalence of smoking among adults in Nebraska is 18-4%. Studies indicate that maltreatment of children alters their brain development, possibly increasing risk for tobacco use. Previous studies have documented associations between childhood maltreatment and adult health behaviors, demonstrating the influence of adverse experiences on tobacco use. We examined prevalence and associations between adverse childhood experiences and smoking among Nebraskans. Methods We analyzed 2011 Nebraska Behavioral Risk Factor Surveillance System (Adverse Childhood Experience module) data, defining adverse childhood experience exposures as physical, sexual, and verbal abuse (ie, direct exposures), and household dysfunction associated with mental illness, substance abuse, divorce, domestic violence, and living with persons with incarceration histories (ie, environmental exposures). We estimated prevalence of exposures, taking into account the complex survey design. We used logistic regression with predicted margins to estimate adjusted relative risk for smoking by direct or environmental exposure. Results Approximately 51% of Nebraskans experienced 1 or more adverse childhood events; 7% experienced 5 or more. Prevalence of environmental exposures (42%) was significantly higher than that of direct exposures (31%). Prevalence of individual exposures ranged from 6% (incarceration of a household member) to 25% (verbal abuse). Adjusted relative risks of smoking for direct and environmental exposures were 1.5 and 1.8, respectively. Conclusion We present a new method of evaluating adverse childhood experience data. Prevalence of adverse childhood experiences is high among Nebraskans, and these exposures are associated with smoking. State-specific strategies to monitor adverse events among children and provide interventions might help to decrease the smoking rate in this population

    Modulation of radio frequency signals by ULF waves

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    The ionospheric plasma is continually perturbed by ultra-low frequency (ULF; 1&amp;ndash;100 mHz) plasma waves that are incident from the magnetosphere. In this paper we present a combined experimental and modeling study of the variation in radio frequency of signals propagating in the ionosphere due to the interaction of ULF wave energy with the ionospheric plasma. Modeling the interaction shows that the magnitude of the ULF wave electric field, &lt;B&gt;e&lt;/B&gt;, and the geomagnetic field, &lt;B&gt;B&lt;/B&gt;&lt;sub&gt;0&lt;/sub&gt;, giving an &lt;B&gt;e&lt;/B&gt;&amp;times;&lt;B&gt;B&lt;/B&gt;&lt;sub&gt;0&lt;/sub&gt; drift, is the dominant mechanism for changing the radio frequency. We also show how data from high frequency (HF) Doppler sounders can be combined with HF radar data to provide details of the spatial structure of ULF wave energy in the ionosphere. Due to spatial averaging effects, the spatial structure of ULF waves measured in the ionosphere may be quite different to that obtained using ground based magnetometer arrays. The ULF wave spatial structure is shown to be a critical parameter that determines how ULF wave effects alter the frequency of HF signals propagating through the ionosphere
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