2,121 research outputs found

    Flows in the solar atmosphere due to the eruptions on the 15th July, 2002

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    <p>Which kind of flows are present during flares? Are they compatible with the present understanding of energy release and which model best describes the observations? We analyze successive flare events in order to answer these questions. The flares were observed in the magnetically complex NOAA active region (AR) 10030 on 15 July 2002. One of them is of GOES X-class. The description of these flares and how they relate to the break-out model is presented in Gary & Moore (2004). The Coronal Diagnostic Spectrometer on board SOHO observed this active region for around 14 h. The observed emission lines provided data from the transition region to the corona with a field of view covering more than half of the active region. In this paper we analyse the spatially resolved flows seen in the atmosphere from the preflare to the flare stages. We find evidence for evaporation occurring before the impulsive phase. During the main phase, the ongoing magnetic reconnection is demonstrated by upflows located at the edges of the flare loops (while downflows are found in the flare loops themselves). We also report the impact of a filament eruption on the atmosphere, with flows up to 300 km s<sup>-1</sup> observed at transition-region temperatures in regions well away from the location of the pre-eruptive filament. Our results are consistent with the predictions of the break out model before the impulsive phase of the flare; while, as the flare progresses, the directions of the flows are consistent with flare models invoking evaporation followed by cooling and downward plasma motions in the flare loops.</p&gt

    Critical Foundations for Civic Engagement: Reimagining Civic Learning for a University Honors Program

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    Scholars are calling attention to shortcomings of service-learning, including the development of civic skills and adoption of a social change framework. Informed by this literature, this article uses a mixed-methods case study to detail the development, and initial outcomes, of a civic engagement course intended to lay a critical foundation for future service. This study documents the process of reimagining the class, formerly organized as a service project, and course evaluations and reflections are used to assess outcomes. Initial assessment signals impact in challenging previous assumptions about service, understanding the multifaceted nature of civic engagement, and motivating future responsible engagement

    Simultaneous Observations of the Chromosphere with TRACE and SUMER

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    Using mainly the 1600 angstrom continuum channel, and also the 1216 angstrom Lyman-alpha channel (which includes some UV continuum and C IV emission), aboard the TRACE satellite, we observed the complete lifetime of a transient, bright chromospheric loop. Simultaneous observations with the SUMER instrument aboard the SOHO spacecraft revealed interesting material velocities through the Doppler effect existing above the chromospheric loop imaged with TRACE, possibly corresponding to extended non-visible loops, or the base of an X-ray jet.Comment: 14 pages, 10 figures, accepted by Solar Physic

    Depth Studies of Wisconsin Loess in Southwestern Iowa: IV. Shear Strength

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    This report is the fourth in a series of papers dealing with depth variations in the engineering properties of Wisconsin-age loess in Iowa. Previous studies have included graduation and in-place density (Davidson, et. al. 1953), clay and carbonate contents (Handy and Davidson, 1956), and organic matter, manganese and iron contents (Daniels et. al. 1960). This paper discusses the variation of the Coulomb shear strength parameters c (cohesive shear strength) and ø (angle of internal friction) in the loess in a cut located in N. W. 1/4 Sec. 3, T77N, R44W, Harrison County, Iowa. This cut was described in detail and proposed as a new type section for the Loveland formation by Daniels and Handy (1959). In general, the hill and cut consist of approximately 130 feet of post-Farmdale loess, over 12 feet of Farmdale loess, over 20 feet of Loveland loess, over oxidized calcareous Kansan (?) till. The upper 30 feet of loess is not cut and was not included in the description by Daniels et. al. (1959). Below this, the upper 40\u27 of the cut has a slope of 50 per cent, and the lower 90 feet is cut into three near-vertical benches

    Doing it differently: Engaging interview participants with imaginative variation

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    Imaginative variation was identified by Husserl (1936/1970) as a phenomenological technique for the purpose of elucidating the manner in which phenomena appear to consciousness. Briefly, by engaging in the phenomenological reduction and using imaginative variation, phenomenologists are able to describe the experience of consciousness, having stepped outside of the natural attitude through the epochē. Imaginative variation is a stage aimed at explicating the structures of experience, and is best described as a mental experiment. Features of the experience are imaginatively altered in order to view the phenomenon under investigation from varying perspectives. Husserl argued that this process will reveal the essences of an experience, as only those aspects that are invariant to the experience of the phenomenon will not be able to change through the variation. Often in qualitative research interviews, participants struggle to articulate or verbalise their experiences. The purpose of this article is to detail a radical and novel way of using imaginative variation with interview participants, by asking the participants to engage with imaginative variation, in order to produce a rich and insightful experiential account of a phenomenon. We will discuss how the first author successfully used imaginative variation in this way in her study of the erotic experience of bondage, discipline, dominance & submission, and sadism & masochism (BDSM), before considering the usefulness of this technique when applied to areas of study beyond sexuality

    Teleworking practice in small and medium-sized firms: Management style and worker autonomy

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    In an empirical study of teleworking practices amongst small and medium-sized enterprises (SMEs) in West London, organisational factors such as management attitudes, worker autonomy and employment flexibility were found to be more critical than technological provision in facilitating successful implementation. Consequently, we argue that telework in most SMEs appears as a marginal activity performed mainly by managers and specialist mobile workers

    Social and cultural origins of motivations to volunteer a comparison of university students in six countries

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    Although participation in volunteering and motivations to volunteer (MTV) have received substantial attention on the national level, particularly in the US, few studies have compared and explained these issues across cultural and political contexts. This study compares how two theoretical perspectives, social origins theory and signalling theory, explain variations in MTV across different countries. The study analyses responses from a sample of 5794 students from six countries representing distinct institutional contexts. The findings provide strong support for signalling theory but less so for social origins theory. The article concludes that volunteering is a personal decision and thus is influenced more at the individual level but is also impacted to some degree by macro-level societal forces

    Automated Detection of Coronal Loops using a Wavelet Transform Modulus Maxima Method

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    We propose and test a wavelet transform modulus maxima method for the au- tomated detection and extraction of coronal loops in extreme ultraviolet images of the solar corona. This method decomposes an image into a number of size scales and tracks enhanced power along each ridge corresponding to a coronal loop at each scale. We compare the results across scales and suggest the optimum set of parameters to maximise completeness while minimising detection of noise. For a test coronal image, we compare the global statistics (e.g., number of loops at each length) to previous automated coronal-loop detection algorithms

    Study of a class of non-polynomial oscillator potentials

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    We develop a variational method to obtain accurate bounds for the eigenenergies of H = -Delta + V in arbitrary dimensions N>1, where V(r) is the nonpolynomial oscillator potential V(r) = r^2 + lambda r^2/(1+gr^2), lambda in (-infinity,\infinity), g>0. The variational bounds are compared with results previously obtained in the literature. An infinite set of exact solutions is also obtained and used as a source of comparison eigenvalues.Comment: 16 page

    Commute replacement and commute displacement the rise of part-day home working

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    Working by telecommunication has been the subject of research attention in transportation studies for many years. Particular consideration has been given to occasional working from home (home working) by (full-time, paid) employees who represent a tangible removal of commute trips on days that people work from home. However, little recognition or attention has been given to the fact that home working not only may be undertaken for part of a week but also may be undertaken for parts of given days. This paper focuses particularly on part-day home working. It defines and uses the term "varied spatiotemporal (VST) working" to describe working days in which at least 30 min of continuous working takes place at home accompanied by work taking place at the workplace. Notably, such home working does not remove the commute trips but can temporally displace one or both of them. The research reported in this paper builds on preceding survey work that had established that the number of people who practice VST working and the number of VST days worked appear to be about double those for full-day home working (which has typically been the focus of research attention). The results presented in this paper are based on 25 in-depth interviews with individuals who practice VST working. The aim of the research was to examine more closely and to understand the nature of VST working and the motivations and constraints for its practice and to consider its potential contribution as a transportation demand management measure
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