The distribution of the ring current: Cluster observations

Extending previous studies, a full-circle investigation of the ring current has been made using Cluster 4-spacecraft observations near perigee, at times when the Cluster array had relatively small separations and nearly regular tetrahedral configurations, and when the Dst index was greater than −30 nT (non-storm conditions). These observations result in direct estimations of the near equatorial current density at all magnetic local times (MLT) for the first time and with sufficient accuracy, for the following observations. The results confirm that the ring current flows westward and show that the in situ average measured current density (sampled in the radial range accessed by Cluster 4–4.5RE) is asymmetric in MLT, ranging from 9 to 27 nAm−2. The direction of current is shown to be very well ordered for the whole range of MLT. Both of these results are in line with previous studies on partial ring extent. The magnitude of the current density, however, reveals a distinct asymmetry: growing from 10 to 27 nAm−2 as azimuth reduces from about 12:00MLT to 03:00 and falling from 20 to 10 nAm−2 less steadily as azimuth reduces from 24:00 to 12:00MLT. This result has not been reported before and we suggest it could reflect a number of effects. Firstly, we argue it is consistent with the operation of region-2 field aligned-currents (FACs), which are expected to flow upward into the ring current around 09:00MLT and downward out of the ring current around 14:00MLT. Secondly, we note that it is also consistent with a possible asymmetry in the radial distribution profile of current density (resulting in higher peak at 4– 4.5RE). We note that part of the enhanced current could reflect an increase in the mean AE activity (during the periods in which Cluster samples those MLT).

The dependence of contrail formation on the weather pattern and altitude in the North Atlantic

Aircraft flying through cold ice-supersaturated air produce persistent contrails which contribute to the climate impact of aviation. Here, we demonstrate the importance of the weather situation, together with the route and altitude of the aircraft through this, on estimating contrail coverage. The results have implications for determining the climate impact of contrails as well as potential mitigation strategies. Twenty-one years of re-analysis data are used to produce a climatological assessment of conditions favorable for persistent contrail formation between 200 and 300 hPa over the north Atlantic in winter. The seasonal-mean frequency of cold ice-supersaturated regions is highest near 300 hPa, and decreases with altitude. The frequency of occurrence of ice-supersaturated regions varies with large-scale weather pattern; the most common locations are over Greenland, on the southern side of the jet stream and around the northern edge of high pressure ridges. Assuming aircraft take a great circle route, as opposed to a more realistic time-optimal route, is likely to lead to an error in the estimated contrail coverage, which can exceed 50% for westbound north Atlantic flights. The probability of contrail formation can increase or decrease with height, depending on the weather pattern, indicating that the generic suggestion that flying higher leads to fewer contrails is not robust.

Lorrie Moore: Mo(o)re than an interim assessment

Lorrie Moore has long shed the image of the precocious talent who won the Seventeen story prize with her first submission as a nineteen-year-old undergraduate, but there is still a sense that her best work may be yet to come. In that respect, this mini special issue represents by no means the final word on Moore, but rather an interim assessment of a career that is already substantial and that promises much more to come. Together these three essays (and introduction) offer a coherent and striking exploration of Moore's work that develops new directions for future criticism and will help cement her growing reputation as one of the most original and distinctive contemporary writers. They sometimes circle around the same stories, even the same quotations, reading them in a variety of frames and picking up (and at) the nuances of Moore's sustained wordplay and careful documenting of space, of identity, of gender. Thus these essays work together rather than separately, layering over multiple understandings of Moore's incisive American literature.

Roll of the rhythmic component in the proactive control of a human hand

In terms of evolution, the strategy of catching prey would have been an important part of survival in a constantly changing environment. A prediction mechanism would have developed to compensate for any delay in the sensory-motor system. In a previous study, “proactive control” was found, in which the motion of the hands preceded the virtual moving target. These results implied that the positive phase shift of the hand motion represents the proactive nature of the visual-motor control system, which attempts to minimize the brief error in the hand motion when the target changes position unexpectedly. In our study, a visual target moves in circle (13 cm diameter) on a computer screen, and each subject is asked to keep track of the target’s motion by the motion of a cursor. As the frequency of the target increases, a rhythmic component was found in the velocity of the cursor in spite of the fact that the velocity of the target was constant. The generation of a rhythmic component cannot be explained simply as a feedback mechanism for the phase shifts of the target and cursor in a sensory-motor system. Therefore, it implies that the rhythmic component was generated to predict the velocity of the target, which is a feed-forward mechanism in the sensory-motor system. Here, we discuss the generation of the rhythmic component and its roll in the feed-forward mechanism.

Evaluation of a boundary integral representation for the conformal mapping of the unit disk onto a simply-connected domain

A representation of the conformal mapping g of the interior or exterior of the unit circle onto a simply-connected domain Ω as a boundary integral in terms ofƒ|∂Ω is obtained, whereƒ :=g -l. A product integration scheme for the approximation of the boundary integral is described and analysed. An ill-conditioning problem related to the domain geometry is discussed. Numerical examples confirm the conclusions of this discussion and support the analysis of the quadrature scheme.

A self-similar expansion model for use in solar wind transient propogation studies

Since the advent of wide-angle imaging of the inner heliosphere, a plethora of techniques have been developed to investigate the three-dimensional structure and kinematics of solar wind transients, such as coronal mass ejections, from their signatures in single- and multi-spacecraft imaging observations. These techniques, which range from the highly complex and computationally intensive to methods based on simple curve fitting, all have their inherent advantages and limitations. In the analysis of single-spacecraft imaging observations, much use has been made of the fixed φ fitting (FPF) and harmonic mean fitting (HMF) techniques, in which the solar wind transient is considered to be a radially propagating point source (fixed φ, FP, model) and a radially expanding circle anchored at Sun centre (harmonic mean, HM, model), respectively. Initially, we compare the radial speeds and propagation directions derived from application of the FPF and HMF techniques to a large set of STEREO/Heliospheric Imager (HI) observations. As the geometries on which these two techniques are founded constitute extreme descriptions of solar wind transients in terms of their extent along the line of sight, we describe a single-spacecraft fitting technique based on a more generalized model for which the FP and HM geometries form the limiting cases. In addition to providing estimates of a transient’s speed and propagation direction, the self-similar expansion fitting (SSEF) technique provides, in theory, the capability to estimate the transient’s angular extent in the plane orthogonal to the field of view. Using the HI observations, and also by performing a Monte Carlo simulation, we assess the potential of the SSEF technique.

Bootstrap prediction intervals for autoregressive time series

The calculation of interval forecasts for highly persistent autoregressive (AR) time series based on the bootstrap is considered. Three methods are considered for countering the small-sample bias of least-squares estimation for processes which have roots close to the unit circle: a bootstrap bias-corrected OLS estimator; the use of the Roy–Fuller estimator in place of OLS; and the use of the Andrews–Chen estimator in place of OLS. All three methods of bias correction yield superior results to the bootstrap in the absence of bias correction. Of the three correction methods, the bootstrap prediction intervals based on the Roy–Fuller estimator are generally superior to the other two. The small-sample performance of bootstrap prediction intervals based on the Roy–Fuller estimator are investigated when the order of the AR model is unknown, and has to be determined using an information criterion.

The absent body: representations of dying early modern women in a selection of seventeenth-century diaries

This article seeks to explore the absence of the body in the depiction of dying women in a selection of seventeenth-century diaries. It considers the cultural forces that made this absence inevitable, and the means by which the physical body was replaced in death by a spiritual presence. The elevation of a dying woman from physical carer to spiritual nurturer in the days before death ensured that gender codes were not broken. The centrality of the body of the dying woman, within a female circle of care and support, was paradoxically juxtaposed with an effacement of the body in descriptions of a good death. In death, a woman might achieve the stillness, silence and compliance so essential to perfect early modern womanhood, and retrospective diary entries can achieve this ideal by replacing the body with images that deflect from the essential physicality of the woman.

Sustainability assessment indicators and methodology for intelligent buildings

The sustainable intelligent building is a building that has the best combination of environmental, social, economic and technical values. And its sustainability assessment is related with system engineering methods and multi-criteria decision-making. Therefore firstly, the wireless monitoring system of sustainable parameters for intelligent buildings is achieved; secondly, the indicators and key issues based on the “whole life circle” for sustainability of intelligent buildings are researched; thirdly, the sustainable assessment model identified on the structure entropy and fuzzy analytic hierarchy process is proposed.

Teaching and learning Chinese: heritage language classroom discourse in Montreal

This paper explores issues of teaching and learning Chinese as a heritage language in a Chinese heritage language school, the Zhonguo Saturday School, in Montreal, Quebec. With a student population of more than 1000, this school is the largest of the eight Chinese Heritage Language schools in Montreal. Students participating in this study were from seven different classes (grade K, two, three, four, five, six, and special class), their ages ranging from 4 to 13 years. The study took place over a period of two years between 2000 and 2002. Focusing on primary level classroom discourse and drawing on the works of Vygotsky and Bakhtin, I examine how teachers and students use language to communicate, and how their communication mediates teaching, learning and heritage language acquisition. Data sources include classroom observations, interviews with students and their teachers, students’ writings, and video and audio taping of classroom activities. Implications for heritage language development and maintenance are discussed with reference to the findings of this study.

Aretusa: continuity, rupture, and space for intervention, 1944-1946

This article focuses on the cultural activity of Aretusa (1944-1946), a journal that was deeply connected to the inner circle of philosopher and politician Benedetto Croce (1866-1952). The article analyses the role played by periodical editors Francesco Flora (1891-1962) and Carlo Muscetta (1912-2004) in shaping the mission and direction of this journal. By drawing on Pierre Bourdieu’s theory of habitus, and the notion of hysteresis in particular, this study details the factors influencing the aesthetic dispositions, political positioning, and the wider impact of historical circumstances on the cultural practice of each editor while at the helm of the review.

For the public without the public

How is the notion of public interest operationalised in the regulatory practices of the International Public Sector Accounting Standards Board (IPSASB)? A fundamental objective in setting international accounting standards for both the private and public sector is to serve the ‘public interest’. Who or what constitutes ‘public interest’ however remains a highly complex and controversial issue. Private sector financial reporting research posits that users (of financial information) are used as a proxy for the ‘public’ and users are further refined to current and potential investors - a small proportion of the public. The debates surrounding public interest are even more contentious in public sector financial reporting which deals with ‘public’ (tax payers’) money. In our study we use Bourdieu’s notion of semi-homogenous fields to show how autonomous and heteronomous pressures from the epistemic community of the accounting profession and political/government interests compete for the right to define the public interest and determine how (by what accounting solutions) this interest is best served. This is a theoretical study grounded in the analysis of empirical data from interviews with the board members of the IPSASB. The main contribution of the paper is to further our understanding of the perceptions of the main decision makers from the ‘inner regulatory circle’ with regards to the problematic construct of public interest. The main findings suggest a paternal and un-reflexive attitude of the board members leading to the conclusion that the public have no real voice in these matters.

Cue properties change timing strategies in group movement synchronisation

To maintain synchrony in group activities, each individual within the group must continuously correct their movements to remain in time with the temporal cues available. Cues might originate from one or more members of the group. Current research suggests that when synchronising movements, individuals optimise their performance in terms of minimising variability of timing errors (asynchronies) between external cues and their own movements. However, the cost of this is an increase in the timing variability of their own movements. Here we investigate whether an individual’s timing strategy changes according to the task, in a group scenario. To investigate this, we employed a novel paradigm that positioned six individuals to form two chains with common origin and termination on the circumference of a circle. We found that participants with access to timing cues from only one other member used a strategy to minimise their asynchrony variance. In contrast, the participant at the common termination of the two chains, who was required to integrate timing cues from two members, used a strategy that minimised movement variability. We conclude that humans are able to flexibly switch timekeeping strategies to maintain task demands and thus optimise the temporal performance of their movements.

The Coronation mantle and the Westminster sanctuary pavement

The Great Sanctuary pavement at Westminster Abbey, on which the kings of England were crowned, features a design of rotated squares, around a central roundel of unusual Egyptian alabaster, set within a circle of bright blue glass. The roundel’s visual resemblance to the world and the firmament is underlined by a surrounding inscription, identifying it as the world, the macrocosm. This paper proposes that the design and meaning of the Great Sanctuary pavement reflect the square macrocosmic mantle in which the English king was wrapped during the coronation ceremony. This paper underlines the special nature of the English coronation mantle within the context of other royal and imperial cosmic mantles. Its square form was unique, and it featured in the English coronation liturgies in a way that European mantles did not. The English liturgies stressed its role as a representation of the world or macrocosm