Studies of iron impurities in YxPr1-xBa2Cu3O7-delta

Pr is the only rare earth which, when substituted for Y in YBa2Cu3O7, significantly alters the superconducting transition temperature T(sub c) without changing the crystal structure. For YxPr1-xBa2Cu3O7-delta with delta approx. equal to 0, T(sub c) is reduced rapidly as x is increased, reaching zero for x about 0.5. For x above 0.5 the compound is antiferromagnetic with a Neel temperature that increases with increasing x, rising to above room temperature for x near 1. A similar behavior is observed when the oxygen deficit delta is increased from zero to 1 with x=0. For the case of Pr substitution, the drop in T(sub c) is believed due to magnetic interactions. For the case of varying delta with x=0, the drop can be attributed to a combination of magnetic interactions, band filling, and changes in crystal structure. To study these effects, the Mossbauer effect of 57 Fe atoms substituted for the Cu atoms has been observed as a function of delta, x, and temperature. The observed spectra are all well described by a two quadrupole-split pairs, a central singlet, and a six-line magnetic hyperfine field pattern. For several Pr compositions both delta and temperature were varied, and the results support the hypothesis that a magnetic interaction exists between the Fe in the Cu lattice and the substitutional Pr atoms

Motivated monitors: the importance of institutional investors’ portfolio weights

Studies of institutional monitoring focus on the fraction of the firm held by institutions. We focus on the fraction of the institution’s portfolio represented by the firm. In the context of acquisitions, we hypothesize that institutional monitoring will be greatest when the target firm represents a significant allocation of funds in the institution’s portfolio. We show that this measure is important in reconciling mixed findings for total institutional ownership in the prior literature. The results indicate that our measure of institutional holdings leads to greater bid completion rates, higher premiums and lower acquirer returns. This empirical evidence provides support for theories predicting a beneficial effect of blockholders in monitoring the firm in general and in enhancing the gains to takeover targets in particular

Effects of phonological phrasing on syntactic structure

Bantu languages are renowned as tone languages that utilize this suprasegmental feature not only on the lexical level to distinguish lexical items, but also on the grammatical level to distinguish clause types. This article investigates one such use of grammatical tone in relative clauses in Bemba where a low tone can be used in place of a segmental relative marker. This low tone relative morpheme functions in conjunction with phrase boundary tone indicated on the head noun and which entails either restrictive or non-restrictive interpretations of relatives. Considering a mapping of XPs to major phonological phrases in the syntax-prosody interface, the resultant phonological phrasing in relatives influences the choice of syntactic structure. In the case at hand, a head-raising analysis provides an optimal mapping between syntax and prosody for restrictives. Further, a more direct influence of phonology on syntax can be seen in a perception-based model like Dynamic Syntax where the on-line building of syntactic trees can gain import from phonological information. © Walter de Gruyter 2007

Julian of Norwich and her children today: Editions, translations and versions of her revelations

The viability of such concepts as "authorial intention," "the original text," "critical edition" and, above all, "scholarly editorial objectivity" is not what it was, and a study of the textual progeny of the revelations of Julian of Norwich--editions, versions, translations and selections--does little to rehabilitate them. Rather it tends to support the view that a history of reading is indeed a history of misreading or, more positively, that texts can have an organic life of their own that allows them to reproduce and evolve quite independently of their author. Julian's texts have had a more robustly continuous life than those of any other Middle English mystic. Their history--in manuscript and print, in editions more or less approximating Middle English and in translations more or less approaching Modern English--is virtually unbroken since the fifteenth century. But on this perilous journey, many and strange are the clutches into which she and her textual progeny have fallen

Characterisation of Walker 256 breast carinoma cells from two tumour cell banks as assessed using two models of secondary brain tumours

Background: Metastatic brain tumours are a common end stage of breast cancer progression, with significant associated morbidity and high mortality. Walker 256 is a rat breast carcinoma cell line syngeneic to Wistar rats and commonly used to induce secondary brain tumours. Previously there has been the assumption that the same cancer cell line from different cell banks behave in a similar manner, although recent studies have suggested that cell lines may change their characteristics over time in vitro. Methods: In this study internal carotid artery injection and direct cerebral inoculation models of secondary brain tumours were used to determine the tumorigenicity of Walker 256 cells obtained from two cell banks, the American Type Culture Collection (ATCC), and the Cell Resource Centre for Medical Research at Tohoku University (CRCTU). Results: Tumour incidence and volume, plus immunoreactivity to albumin, IBA1 and GFAP, were used as indicators of tumorigenicity and tumour interaction with the host brain microenvironment. CRCTU Walker 256 cells showed greater incidence, larger tumour volume, pronounced blood–brain barrier disruption and prominent glial response when compared to ATCC cell line. Conclusions: These findings indicate that immortalised cancer cell lines obtained from different cell banks may have diverse characteristics and behaviour in vivo.Kate M Lewis, Elizabeth Harford-Wright, Robert Vink and Mounir N Ghabrie

Phonological and syntactic phrasing in Bemba relatives

Tone as a distinctive feature used to differentiate not only words but also clause types, is a characteristic feature of Bantu languages. In this paper we show that Bemba relatives can be marked with a low tone in place of a segmental relative marker. We treat this low tone as a morpheme rather than as just triggering a change in tone pattern that can then be related to relativization. The low tone strategy of relativization, which imposes a restrictive reading of relatives, manifests a phonological phrasing that requires the head noun to be phrased together with the relative clause that it modifies as opposed to non-restrictives where this is not the case. The paper shows that the resultant phonological phrasing favours a head-raising analysis of relativization where the head noun is considered to be inside CP. Despite the syntactic use of the relative tonal morpheme we see that it is also subject to purely phonological constraints that results in its being unable to be used to mark headless relatives. This paper therefore highlights the phonology-syntax connection and shows that phonology can directly inform syntactic analyses. © Walter de Gruyter

Different Myosin Head Conformations in Bony Fish Muscles Put into Rigor at Different Sarcomere Lengths

At a resting sarcomere length of approximately 2.2 µm bony fish muscles put into rigor in the presence of BDM (2,3-butanedione monoxime) to reduce rigor tension generation show the normal arrangement of myosin head interactions with actin filaments as monitored by low-angle X-ray diffraction. However, if the muscles are put into rigor using the same protocol but stretched to 2.5 µm sarcomere length, a markedly different structure is observed. The X-ray diffraction pattern is not just a weaker version of the pattern at full overlap, as might be expected, but it is quite different. It is compatible with the actin-attached myosin heads being in a different conformation on actin, with the average centre of cross-bridge mass at a higher radius than in normal rigor and the myosin lever arms conforming less to the actin filament geometry, probably pointing back to their origins on their parent myosin filaments. The possible nature of this new rigor cross-bridge conformation is discussed in terms of other well-known states such as the weak binding state and the ‘roll and lock’ mechanism; we speculate that we may have trapped most myosin heads in an early attached strong actin-binding state in the cross-bridge cycle on actin