Ionospheric and geomagnetic responses to changes in IMF B_Z: a superposed epoch study

Superposed epoch studies have been carried out in order to determine the ionospheric response at mid-latitudes to southward turnings of the interplanetary magnetic field (IMF). This is compared with the geomagnetic response, as seen in the indices K p, AE and Dst. The solar wind, IMF and geomagnetic data used were hourly averages from the years 1967–1989 and thus cover a full 22-year cycle in the solar magnetic field. These data were divided into subsets, determined by the magnitudes of the southward turnings and the concomitant increase in solar wind pressure. The superposed epoch studies were carried out using the time of the southward turning as time zero. The response of the mid-latitude ionosphere is studied by looking at the F-layer critical frequencies, f o F2, from hourly soundings by the Slough ionosonde and their deviation from the monthly median values, δf o F2. For the southward turnings with a change in B z of δB z > 11.5 nT accompanied by a solar wind dynamic pressure P exceeding 5 nPa, the F region critical frequency, f o F2, shows a marked decrease, reaching a minimum value about 20 h after the southward turning. This recovers to pre-event values over the subsequent 24 h, on average. The Dst index shows the classic storm-time decrease to about −60 nT. Four days later, the index has still to fully recover and is at about −25 nT. Both the K p and AE indices show rises before the southward turnings, when the IMF is strongly northward but the solar wind dynamic pressure is enhanced. The average AE index does register a clear isolated pulse (averaging 650 nT for 2 h, compared with a background peak level of near 450 nT at these times) showing enhanced energy deposition at high latitudes in substorms but, like K p, remains somewhat enhanced for several days, even after the average IMF has returned to zero after 1 day. This AE background decays away over several days as the Dst index recovers, indicating that there is some contamination of the currents observed at the AE stations by the continuing enhanced equatorial ring current. For data averaged over all seasons, the critical frequencies are depressed at Slough by 1.3 MHz, which is close to the lower decile of the overall distribution of δf o Fl values. Taking 30-day periods around summer and winter solstice, the largest depression is 1.6 and 1.2 MHz, respectively. This seasonal dependence is confirmed by a similar study for a Southern Hemisphere station, Argentine Island, giving peak depressions of 1.8 MHz and 0.5 MHz for summer and winter. For the subset of turnings where δB z > 11.5 nT and P ≤ 5 nPa, the response of the geomagnetic indices is similar but smaller, while the change in δf o F2 has all but disappeared. This confirms that the energy deposited at high latitudes, which leads to the geomagnetic and ionospheric disturbances following a southward turning of the IMF, increases with the energy density (dynamic pressure) of the solar wind flow. The magnitude of all responses are shown to depend on δB z . At Slough, the peak depression always occurs when Slough rotates into the noon sector. The largest ionospheric response is for southward turnings seen between 15–21 UT.

The Devil’s Daughters and a question of translation between Occitan and Anglo-Norman French: ‘De las .vii. filhas del diable’ (British Library Add. MS 17920).

The evidence for vernacular-to-vernacular translation is hard to demonstrate in medieval Romance languages. This article analyses a hypothesis published a century ago that there is an identifiable Anglo-Norman source for an Occitan prose text. Both texts spring from a Latin exemplum in which the seven capital vices are personified as the Devil's daughters, married off to seven social categories (the clergy, knights, peasants, etc.). Although the hypothesis is disproved, it remains that the dialogue between Anglo-Norman French and Occitan has been overlooked, and deserves further exploration.

The Vida of Queen Fredegund in Tote Listoire de France: vernacular translation and genre in thirteenth-century French and Occitan literature

This article examines the role that translation may have played in the development of medieval vernacular literature. It analyses an extract of an early 13th-c. translation into a hybrid French-Occitan vernacular of an 8th-c. historical text, the 'Liber Historiae Francorum'. The translation coincides with the adoption of narrative prose both in Old French and in Occitan literature, which reflects a growing interest in historical writings. The second half of the article compares the anecdote with the narrative structures and content of one of the troubadour 'vidas' and 'razos' - biographical texts in prose that emerged in the same period and regions as this translation. The article concludes by suggesting that the new vernacular genre shares narrative features with the early medieval Latin text that are preserved in its translation.

Beyond description to pattern: The contribution of Batesonian epistemology to critical realist research

This paper proposes a limitation to epistemological claims to theory building prevalent in critical realist research. While accepting the basic ontological and epistemological positions of the perspective as developed by Roy Bhaskar, it is argued that application in social science has relied on sociological concepts to explain the underlying generative mechanisms, and that in many cases this has been subject to the effects of an anthropocentric constraint. A novel contribution to critical realist research comes from the work and ideas of Gregory Bateson. This is in service of two central goals of critical realism, namely an abductive route to theory building and a commitment to interdisciplinarity. Five aspects of Bateson’s epistemology are introduced: (1) difference, (2) logical levels of abstraction, (3) recursive causal loops, (4) the logic of metaphor, and (5) Bateson’s theory of mind. The comparison between Bateson and Bhaskar’s ideas is seen as a form of double description, illustrative of the point being raised. The paper concludes with an appeal to critical realists to start exploring the writing and outlook of Bateson himself.

Technology, ritual and Anglo-Saxon agrarian production: the biography of a seventh-century century plough coulter from Lyminge, Kent

The discovery of an unusual early medieval plough coulter in a well-dated Anglo-Saxon settlement context in Kent suggests that continentally derived technology was in use in this powerful kingdom centuries before heavy ploughs were first depicted in Late Saxon manuscripts. The substantial investment required to manufacture the coulter, the significant damage and wear that it sustained during use and the circumstances of its ultimate ritual deposition are explored. Investigative conservation, high-resolution recording and metallographic analysis illuminate the form, function and use-life of the coulter. An examination of the deposition contexts of plough-irons in early medieval northern Europe sheds important new light on the ritual actions of plough symbolism in an age of religious hybridity and transformation.

On the threshold of adulthood: a new approach for the use of maturation indicators to assess puberty in adolescents from medieval England

Objectives: This study provides the first large scale analysis of the age at which adolescents in medieval England entered and completed the pubertal growth spurt. This new method has implications for expanding our knowledge of adolescent maturation across different time periods and regions. Methods: In total, 994 adolescent skeletons (10-25 years) from four urban sites in medieval England (AD 900-1550) were analysed for evidence of pubertal stage using new osteological techniques developed from the clinical literature (i.e. hamate hook development, CVM, canine mineralisation, iliac crest ossification, radial fusion). Results: Adolescents began puberty at a similar age to modern children at around 10-12 years, but the onset of menarche in girls was delayed by up to 3 years, occurring around 15 for most in the study sample and 17 years for females living in London. Modern European males usually complete their maturation by 16-18 years; medieval males took longer with the deceleration stage of the growth spurt extending as late as 21 years. Conclusions: This research provides the first attempt to directly assess the age of pubertal development in adolescents during the tenth to seventeenth centuries. Poor diet, infections, and physical exertion may have contributed to delayed development in the medieval adolescents, particularly for those living in the city of London. This study sheds new light on the nature of adolescence in the medieval period, highlighting an extended period of physical and social transition.

Is children's reading “good enough”? Links between online processing and comprehension as children read syntactically ambiguous sentences

We monitored 8- and 10-year-old children’s eye movements as they read sentences containing a temporary syntactic ambiguity to obtain a detailed record of their online processing. Children showed the classic garden-path effect in online processing. Their reading was disrupted following disambiguation, relative to control sentences containing a comma to block the ambiguity, although the disruption occurred somewhat later than would be expected for mature readers. We also asked children questions to probe their comprehension of the syntactic ambiguity offline. They made more errors following ambiguous sentences than following control sentences, demonstrating that the initial incorrect parse of the garden-path sentence influenced offline comprehension. These findings are consistent with “good enough” processing effects seen in adults. While faster reading times and more regressions were generally associated with better comprehension, spending longer reading the question predicted comprehension success specifically in the ambiguous condition. This suggests that reading the question prompted children to reconstruct the sentence and engage in some form of processing, which in turn increased the likelihood of comprehension success. Older children were more sensitive to the syntactic function of commas, and, overall, they were faster and more accurate than younger children.

The Earls of Kildare and their books at the end of the Middle Ages

The two surviving inventories of the library of the Fitzgerald Earls of Kildare bear witness to a particularly large and diverse collection of books in the Earls' castle at Maynooth, Co. Kildare. Between them, the lists record well over one hundred separate items in four languages: Latin, French, English and Irish. This paper traces the history of the library and analyses the Fitzgeralds' particular interests as book collectors and as readers. It provides the first full published set of suggested identifications and bibliographical details for the books at Maynooth. It also includes a fresh transcription of the library lists and a discussion of the manuscript context in which they are preserved. Sources like the Kildare library lists provide valuable evidence for the potential circulation of a wide range of non-native manuscripts and prints in late-medieval Ireland.

Roger Machado, Perkin Warbeck and heraldic espionage

An examination of the medieval herald's role in international espionage. It is argued that heralds were used as spies, despite their creation oaths stipulating that their job should not encompass this task. The herald Roger Machado's involvement in the diplomacy surrounding the pretender to the English throne, Perkin Warbeck, is scrutinized and is offered as evidence that Machado did act as a spy for Henry VII on the international stage.

Examining the relationships between Holocene climate change, hydrology, and human society in Ireland

This thesis explores human-environment interactions during the Mid-Late Holocene in raised bogs in central Ireland. The raised bogs of central Ireland are widely-recognised for their considerable palaeoenvironmental and archaeological resources: research over the past few decades has established the potential for such sites to preserve sensitive records of Holocene climatic variability expressed as changes in bog surface wetness (BSW); meanwhile archaeological investigations over the past century have uncovered hundreds of peatland archaeological features dating from the Neolithic through to the Post-Medieval period including wooden trackways, platforms, and deposits of high-status metalwork. Previous studies have attempted to explore the relationship between records of past environmental change and the occurrence of peatland archaeological sites reaching varying conclusions. More recently, environmentally-deterministic models of human-environment interaction in Irish raised bogs at the regional scale have been explicitly tested leading to the conclusion that there is no relationship between BSW and past human activity. These relationships are examined in more detail on a site-by-site basis in this thesis. To that end, testate amoebae-derived BSW records from nine milled former raised bogs in central Ireland were produced from sites with known and dated archaeological records. Relationships between BSW records and environmental conditions within the study area were explored through both the development of a new central Ireland testate amoebae transfer function and through comparisons between recent BSW records and instrumental weather data. Compilation of BSW records from the nine fossil study sites show evidence both for climate forcing, particularly during 3200-2400 cal BP, as well as considerable inter-site variability. Considerable inter-site variability was also evident in the archaeological records of the same sites. Whilst comparisons between BSW and archaeological records do not show a consistent linear relationship, examination of records on a site-by-site basis were shown to reveal interpretatively important contingent relationships. It is concluded therefore, that future research on human-environment interactions should focus on individual sites and should utilise theoretical approaches from the humanities in order to avoid the twin pitfalls of masking important local patterns of change, and of environmental determinism.