bluuebunny/crossref_metadata_2025 huggingface dataset:
II.—Bronze Age Metalwork from Lincolnshire
Authors: Davey P. J.
Published: April 2011

The aim of this paper has been to collect together, describe, and illustrate, all known finds of Lincolnshire Bronze Age metalwork. It is based on the assumption that for future research adequate publication of the available material is a primary requirement. There is a brief survey of some of the problems involved in interpreting the typology, chronology, distribution, and over-all cultural significance of the finds. This is followed by a catalogue which contains as accurate documentation for each object as is possible. The bibliography is intended to include all original references to Lincolnshire objects, all the more general works referred to in the text, and other relevant literature.
III.—The Gates of Roman Lincoln
Authors: Thompson F. H. , Whitwell J. B.
Published: April 2011

The Royal Archaeological Institute held its summer meeting in 1946 in Lincoln and members were able to inspect excavations undertaken by the Lincoln Archaeological Research Committee, formed in the previous year. Volume 103 of the Archaeological Journal was published in 1947 and was largely devoted to the archaeology of Lincoln and Lincolnshire. A notable feature was the late Sir Ian Richmond's paper, ‘The Roman City of Lincoln’, in which he synthesized the widely scattered evidence into one coherent picture, followed by an equally valuable general study, ‘The Four Coloniae of Roman Britain’. His account of Roman Lincoln included a section on the four gates of the original colonia on the hill-top above the Witham (fig. 1), in which he included reconstructed plans of those on the north and south. It would have been remarkable if all his conjectures had proved accurate; he was already aware, well before his death, of the extent to which excavation had corrected his suggestions and was able to make a brief mention of this in print.
VI.—The Reliquary of St. Petroc and the Ivories of Norman Sicily
Authors: Pinder-Wilson R. H. , Brooke C. N. L.
Published: April 2011

A little less than 800 years ago the bones of St. Petroc were removed from his priory church in Bodmin by a seditious canon and carried into Brittany. About a year later, after the prior of Bodmin had mobilized his friend, the head of the royal chancery, and through him King Henry II himself, and the regent of Brittany, not without some miraculous interventions by the saint himself, the bones were returned to Bodmin in an ivory casket and solemnly installed again in the priory church by the learned and saintly Bishop Bartholomew.
II. Silver Picture Plates of Late Antiquity: A.D. 300 to 700
Authors: Toynbee J. M. C. , Painter K. S.
Published: April 2011

One of the first questions likely to be asked by someone confronted for the first time by the great Oceanus plate (missorium) from Mildenhall (I, pl. VIIa)** is, What was it used for? The answer is that neither it nor any of its fellow flat, decorated plates of silver, whether round or rectangular, to be surveyed in this paper, was everusedfor practical, domestic purposes to serve as table-ware. It is hard to imagine the highly sophisticated and often elaborate relief- or incised-work that they carry being concealed beneath piles of fruit, vegetables, cakes, or portions of meat or fish greasy with gravy or sauce. These reliefs or engravings, whether covering the whole surface of a plate or confined to its central medallion or to its central medallion and flange, were essentiallypictures for displayin their owners' houses, or in temples or churches, probably mounted on brackets or shelves fixed to walls or to cupboards or chests (some are pierced by one or more holes as though for suspension on a wall), where they could be studied and admired for their beauty as works of art and/or their political, cultic or mythological implications.
IV. The Anglo-Saxon Friezes at Breedon-on-the-Hill, Leicestershire
Authors: Jewell R. H. I.
Published: April 2011

Let into various walls inside the church of St. Mary and St. Hardulph at Breedon-on-the-Hill, Leicestershire, is a group of frieze sculpture and relief-carved panels. It is now generally accepted that these are of Anglo-Saxon origin, and have been reused in the present church, of which no part is earlier than the twelfth century.
VII. The Glass of Herkenrode Abbey
Authors: Bemden Yvette Vanden , Kerr Jill , Opsomer Carmelia
Published: April 2011

In 1865 the great antiquarian connoisseur of medieval painted glass, Charles Winston, said of the Herkenrode glass at Lichfield: ‘I do not know of any works in glass which are so powerful, without in the least degree violating the essential conditions of art’. This study, which illustrates all the glass of known Herkenrode provenance for the first time, demonstrates clearly the vision and skill of the glaziers in translating highly sophisticated designs into glass of startling luminosity and in achieving the visual power and transcendence of the limitations of the medium recognized by Winston.
IX. The Devonshire Parure
Authors: Scarisbrick Diana
Published: April 2011

On 13th May 1856 Granville George Leveson Gower, 2nd Earl Granville (1819–91), Liberal diplomat and politician, wrote to Viscount Canning announcing his appointment as representaive of Queen Victoria at the coronation of Tsar Alexander II in Moscow that summer. He added that before accepting he had consulted his wife Marie, who had ‘pronounced some sage aphorisms, but danced a hornpipe and lamented that it would be necessary to buy twenty gowns and have her diamonds reset’. Marie Granville's sense of the importance of jewellery on such an occasion was shared by her husband's uncle, William, 6th Duke of Devonshire (1790–1858), who, on behalf of George IV, had attended the coronation of Tsar Nicholas I in 1825. Having himself experienced Russian hospitality at its most magnificent he knew what was expected of the representatives of foreign royalty, and he not only gave the Granvilles money and lent them also his silver, but he commissioned a set of jewels incorporating hundreds of diamonds and eighty-eight cameos and intaglios from his ancestral collection.
V.—Westminster Abbey: The Timber Roofs of the Collegiate Church of St. Peter at Westminster
Authors: McDowall R. W. , Smith J. T. , Stell C. F.
Published: April 2011

The timber roofs above the main vaults of the abbey, coeval with the parts of the building they cover, are illustrated in J. P. Neale and E. W. Brayley, History and Antiquities of the Abbey Church of St. Peter, Westminster (1823), ii. These important medieval roofs are described only very briefly in an addendum to the Inventory of Westminster Abbey by the Royal Commission on Historical Monuments published in 1924 (entry no. 22a, slip p. 58), and no detailed description of them has so far been published. They underwent heavy restoration at the beginning of the eighteenth century, but survived in great part until the present repairs under the direction of Mr. S. E. Dykes Bower were put in hand. By 1964 the whole of the nave roof had been reconstructed and the roof over the south transept had been taken down and reconstruction was in progress. No major repairs to the roofs of the presbytery or the north transept had been started. At this stage, by kind permission of the Dean and Chapter, the Royal Commission was given facilities to make detailed records of the surviving medieval structures. In the following account the documentary evidence relating to their building and repair is outlined, their construction is described in some detail, and, finally, their historical context and their setting in the general development of roof construction are discussed. The photographs were taken by Mr. J. Parkinson, and the work has been co-ordinated by Mr. A. R. Dufty, Secretary to the Commission.
II.—The Dover Ring-sword and Other Sword-rings and Beads
Authors: Evison Vera I.
Published: April 2011

In August 1951 skeletons were found during the building operations of the Buckland Estate, Dover, Kent, and were brought to the notice of the late W. P. D. Stebbing, who visited the site and supervised the excavation of one grave. The contents of this grave were sent to the Inspectorate of Ancient Monuments, and the writer supervised the remainder of the excavation under the auspices of the Inspectorate.
I.—The Sark Hoard
Authors: Allen D. F.
Published: April 2011

On 9th March 1718 five citizens of the island of Sark, William Tanquerel, Henry de Carteret, Pirre de Carteret, Philipe Guille, and Nicholas Guille appeared before the Seneschal. They had been summoned by the Procurator Substitute, Philipe Slowley, on behalf of the Very Honourable Seigneur, Jean, Lord Carteret, Baron of Hawnes, Seigneur of St. Ouen, Sark, etc. Philipe Guille had been punished earlier in the day for having allowed his dog to run loose against the regulations. As a result of the proceedings the Seneschal ordered the five to deliver into the hands of the Procurator intact a treasure which they had found in the ground in making a ditch in a farm, commonly called La Voroque, which belonged to William Tanquerel, and this was duly done. The event is recorded in the Ledger for 1718, preserved in the Greffe Office in Sark.
III.—The Tombs of Archbishops Walter de Gray (1216–55) and Godfrey de Ludham (1258–65) in York Minster, and their Contents
Authors: Ramm H. G.
Published: April 2011

The restoration in 1967–8 of the tomb of Archbishop Walter de Gray in the south transept of York Minster was undertaken during the general programme of restoration of the Minster as a whole. The dismantling of the tomb afforded an opportunity to open the underlying coffin and examine its contents. Both coffin and contents proved to be of outstanding interest and the results were communicated to the Society on 7th November 1968 by some of the authors responsible for this paper. The second tomb, identified as that of Archbishop Godfrey de Ludham, was opened in February 1969 and the contents, though less spectacular, afford so many useful comparisons with those from the de Gray burial that it was thought useful to present the findings in a combined paper. I must emphasize that my own contributions, on the pastoral staves, are brief factual statements inserted in the interests of speedy publication; they are not intended to replace the full discussion of them which had originally been hoped for from Mr. Michael Taylor before he relinquished his post at the British Museum. The Society is deeply indebted to the Dean, the Very Reverend Alan Richardson, M.A., D.D., and Chapter of York Minster for permitting the original communication and for encouraging the subsequent study and publication of the notable material from both these tombs. Grateful thanks are also due to the Royal Commission on Historical Monuments (England) and the Trustees of the British Museum for the provision of the excellent photographs which illustrate this paper (pls. XXXVI–LXV) and for their permission to publish them.
VI.—Isaac Fuller's Paintings of Charles II's Escape after the Battle of Worcester
Authors: Croft-Murray Edward
Published: April 2011

Charles II's hiding in the Royal Oak of Boscobel has taken its place among those picturesque memorabilia—such as Alfred and the cakes, Canute and the waves, Bruce and the spider, Drake and his bowls, and Raleigh and his cloak—which have enlivened our history books both before and after 1066-and-all-that. And of all these episodes it is perhaps the story of the Royal Oak which rings the truest: two versions of it, England's Triumph by an anonymous author, and Thomas Blount's Boscobel, were both published in the year of the Restoration, 1660; and the chief actor himself was always ready to give his own account of the adventure, and on two occasions, on 3rd and 5th October 1680, entertained Samuel Pepys with it.
II.—A Technical Study of the Designs on the British Mirror Series
Authors: Lowery P. R. , Savage R. D. A. , Wilkins R. L.
Published: April 2011

We have studied the techniques of decoration of the backs of the British bronze mirrors according to the methods outlined by us in Lowery, Savage, Wilkins, 1971, 176 f., and the construction of the design on the newly discovered Holcombe mirror (Fox, 1973). Our intention is to examine the technical relationships between the mirror backs and to note some details of bronzesmiths' practice which they illustrate, and on which the Holcombe mirror sheds much light. Our conclusions are based mainly on examination of silicone rubber moulds which, with the co-operation of the museums concerned, have been made of all the decorated mirror backs now available. In default of a similar study of any extensive body of other material, no comparisons outside the mirror series are cited. We are not here concerned with mirrors whose backs are undecorated.
III.—The Excavation of the Roman Amphitheatre at Chester
Authors: Thompson F. H. , Sunter Nigel J. , Weaver O. J.
Published: April 2011

Amphitheatres, although not so ubiquitous as, say, bath-buildings, were common enough in the Roman world to attract a set of terms applicable to their very distinctive structural features. It is true that they varied in construction from a simple earth bank to an elaborate masonry building like the Colosseumat Rome. But certain characteristics were constant, and it seems useful to list the technical terms used to describe amphitheatres. Some of these are scarcely applicable to the relatively simple Chester amphitheatre, while others are etymologically rather dubious. This list itself is almost entirely confined to the structural features since there are easily accessible descriptions of the spectacles which took place within amphitheatres. Previous lists have been given by Dyggve in his description of the amphitheatre at Salona and by Heidenreich in his report on the civil amphitheatre of Colonia Traiana at Xanten.
IV. The Discoveries of the Westminster Retable
Authors: Macek Pearson M.
Published: April 2011

The Westminster Retable is the most important thirteenth-century panel painting to survive from northern Europe and, quite arguably, from all of western Europe (pl. XXVIa). An oak panel measuring approximately 0.95m high by 3.33m wide, it is divided vertically into five compartments. In the centre is the figure of Christ, standing, blessing and holding in his left hand an orb or globe upon which is painted a delicate miniature landscape (pl. XXVIb). He is flanked by the Virgin Mary and St John the Evangelist who both hold palm fronds. Iconographically this grouping is unique in medieval art. Each figure stands in an architectural niche of high Gothic design. To either side of the central group are four medallions arranged in the Islamic star-and-cross pattern. Each of these eight-pointed star medallions contained a narrative scene, of which three on the left survive: the Raising of the Daughter of Jairus, the Healing of the Blind Man and the Feeding of the Five Thousand (pl. XXVIc). Such miracle scenes from the adult life of Christ were but rarely depicted in the Middle Ages. At either end of the panel are niches for standing figures of saints; only St Peter on the left survives, although ghostly vestiges of his counterpart, presumably St Paul, on the right remain visible.
VI. The Pilgrims' Hall, Winchester. Hammerbeams, Base Crucks and Aisle-Derivative Roof Structures
Authors: Crook John
Published: April 2011

The roof of the so called ‘Pilgrims’ Hall’, Winchester, now dated to c. 1308, has long been recognized as one of the earliest surviving examples of hammerbeam construction. It is somewhat surprising, therefore, that the complete medieval structure, of which the Pilgrims’ Hall forms rather less than half, has not previously been investigated in detail. In its original form it was a six bay building covered by a single roof, which, though of one constructional phase, employed a variety of principal truss types (fig. 1). The three bays at the north end of the complex have masonry walls: they comprise the actual Pilgrims’ Hall, whose most impressive feature is its pair of hammerbeam trusses (pl. XLa). The other three bays had timber framed walls, and were subdivided into a second, two bay hall with a central base cruck truss, and a single bay at the south end of the building. In this paper the term ‘Pilgrims’ Hall’ is used to denote only the three bay hammerbeam hall, while the entire original structure is referred to as the ‘Pilgrims’ range’.

The roof and timber framing of the complex must surely rank with those few structures that, in the words of the late R. T. Mason, ‘stand out for their contribution to overall knowledge’. The outstanding significance of the Pilgrims' range in the study of early medieval carpentry is that it included four major ‘aisle-derivative’ roof truss types in a single building: a true aisled truss, a base cruck truss, two hammerbeam trusses, and at least one raised aisle truss. The existence of continuous longitudinal members (arcade plates, cornice plates and a central purlin) and the uniform upper roof structure throughout the length of the range show that the entire roof was erected in a single campaign.
Archaeology and the unstoppable excavation machine. A Swedish point of view
Authors: Nilsson Björn
Published: April 2011

In trying to understand why archaeology is so strongly associated with the method of excavation, this paper examines different relationships between excavation, archaeology, archaeologists and modern society.
Pullout tests of root analogs and natural root bundles in soil: Experiments and modeling
Authors: Schwarz M. , Cohen D. , Or D.
Published: April 2011

Root‐soil mechanical interactions are key to soil stability on steep hillslopes. Motivated by new advances and applications of the Root Bundle Model (RBM), we conducted a series of experiments in the laboratory and in the field to study the mechanical response of pulled roots. We systematically quantified the influence of different factors such as root geometry and configuration, soil type, and soil water content considering individual roots and root bundles. We developed a novel pullout apparatus for strain‐controlled field and laboratory tests of up to 13 parallel roots measured individually and as a bundle. Results highlight the importance of root tortuosity and root branching points for prediction of individual root pullout behavior. Results also confirm the critical role of root diameter distribution for realistic prediction of global pullout behavior of a root bundle. Friction between root and soil matrix varied with soil type and water content and affected the force‐displacement behavior. Friction in sand varied from 1 to 17 kPa, with low values obtained in wet sand at a confining pressure of 2 kPa and high values obtained in dry sand with 4.5 kPa confining pressure. In a silty soil matrix, friction ranged between 3 kPa under wet and low confining pressure (2 kPa) and 6 kPa in dry and higher confining pressure (4.5 kPa). Displacement at maximum pullout force increased with increasing root diameter and with tortuosity. Laboratory experiments were used to calibrate the RBM that was later validated using six field measurements with natural root bundles of Norway spruce (Picea abies L.). These tests demonstrate the progressive nature of root bundle failure under strain‐controlled pullout force and provide new insights regarding force‐displacement behavior of root reinforcement, highlighting the importance of considering displacement in slope stability models. Results show that the magnitude of maximum root pullout forces (1–5 kPa) are important for slope stability. The force‐displacement relations characterized in this study are fundamental inputs for quantifying the resistive force redistribution on vegetated slopes and may provide explanation for abrupt loss of strength during landslide initiation and deformation.
Flaw-tolerance in silk fibrils explains strength, extensibility and toughness of spider silk
Authors: Arslan Melis , Buehler Markus
Published: April 2011

Silk is an ancient but remarkably strong, extensible and tough material made from simple protein building blocks. Earlier work has shown that the particular molecular geometry of silk with a composite of semi-amorphous and nanocrystalline beta-sheet protein domains provides the structural basis for its characteristic softening-stiffening behavior and remarkable strength at the nanoscale. Yet, an open question remains as to how these nanoscale properties are upscaled so effectively to create strong, extensible and tough silk fibers. Here we discover that the geometric confinement of fibrils to ≈50-100 nm width and arranged in bundles to form larger-scale silk fibers, is the key to explaining the upscaling of the mechanical properties of silk from the atomistic scale upwards. We find that under this geometric confinement, hundreds of thousands of protein domains unfold simultaneously and thereby act synergistically to resist deformation and failure, providing access to enhanced large-scale strength, extensibility and toughness. Moreover, since the material is in a flaw-tolerant state under this geometric confinement, structural inhomogeneities such as cavities or tears that typically act as stress concentrators do not compromise the material performance. Indeed, experimental work showed that the diameter of silk fibrils that make up larger-scale silk fibers are on the order of 20-100 nm, in agreement with our findings. The exploitation of this mechanism in engineering design enables the synthesis of hierarchical fiber materials for superior performance despite limited and inferior building blocks.
The Effect of Ponderal Index at Birth on the Relationships Between Common LEP and LEPR Polymorphisms and Adiposity in Adolescents
Authors: Labayen Idoia , Ruiz Jonatan R. , Moreno Luis A. , Ortega Francisco B. , Beghin Laurent , DeHenauw Stefaan , Benito Pedro J. , Diaz Ligia E. , Ferrari Marika , Moschonis George , Kafatos Anthony , Molnar Dénes , Widhalm Kurt , Dallongeville Jean , Meirhaeghe Aline , Gottrand Frédéric ,   On behalf of the HELENA study group
Published: April 2011

This study examined the effect of ponderal index (PI) at birth on the relationships between eight common polymorphisms of the leptin (LEP) and leptin receptor (LEPR) genes and adiposity in adolescents. A total of 823 European adolescents (45.4% girls) aged 14.8 ± 1.4 years were genotyped for the LEP (rs2167270, rs12706832, rs10244329, rs2071045, and rs3828942) and LEPR (rs1137100, rs1137101, and rs8179183) polymorphisms. The PI was calculated from parental reports of birth weight and length. Fat mass index (FMI) was calculated. Analyses were adjusted for relevant confounders. An “adiposity‐risk‐allele score” based on genotypes at the three single‐nucleotide polymorphisms (SNPs) associated with adolescents' FMI in adolescents within the lower tertile of PI was calculated. The LEP rs10244329 and rs3828942 polymorphisms were associated with higher FMI only in adolescents within the lower PI tertile (+0.55 kg/m2 per minor T allele, P = 0.040, and +0.58 kg/m2 per major G allele, P = 0.028, respectively). The LEPR rs8179183 polymorphism was significantly associated with higher FMI in adolescents within the lower PI tertile (+0.87 kg/m2 per minor C allele, P = 0.006). After correction for multiple comparisons, only the association between the LEPR rs8179183 and FMI persisted. However, each additional risk allele conferred 0.53 kg/m2 greater FMI in adolescents within the lower tertile of PI (P = 0.008). In conclusion, our results suggest that those adolescents born with lower PI could be more vulnerable to the influence of the LEP rs10244329 and rs3828942 polymorphisms and LEPR rs8179183 polymorphism on total adiposity content. Due to the relatively small sample size, these findings should be replicated in further larger population samples.
Attitudes to Publicly Funded Obesity Treatment and Prevention
Authors: Lund Thomas B. , Sandøe Peter , Lassen Jesper
Published: April 2011

The aim of this study was to investigate the Danish public's support for publicly funded obesity treatment and prevention. It was also examined whether levels of support could be explained by dislike of obese people and/or the belief that those who are obese are personally responsible for their condition. A representative survey of members of the Danish public (N = 1,141) was conducted using a web‐based questionnaire. The survey was designed to assess attitudes to public funding for obesity‐related health care, and to investigate the impact, on those attitudes, of dislike of obese people, the perceived controllability of obesity, self‐reported BMI, and additional attitudinal and socio‐demographic characteristics. Public funding of some obesity treatments, such as weight‐loss surgery, attracted only limited public support. A majority of the Danish public did support “softer” treatment interventions and preventive initiatives. Attitudes to the treatment of obesity were clearly best predicted by the belief that individuals are personally responsible for their own obesity. Dislike of obese persons had no direct effect on the preference for collective treatment initiatives and only a small effect on support for publicly funded obesity prevention. The high level of disapproval for publicly funded obesity treatment should be cause for concern for decision makers aiming to ensure equal access to health care. Since it is the belief that obese people are personally responsible which explains this disapproval, strategies for challenging public opinion on this issue are discussed.
Optofluidic Tomography on a Chip
Authors: Isikman Serhan O. , Bishara Waheb , Zhu Hongying , Ozcan Aydogan
Published: April 2011

Using lensfree holography we demonstrate optofluidic tomography on a chip. A partially coherent light source is utilized to illuminate the objects flowing within a microfluidic channel placed directly on a digital sensor array. The light source is rotated to record lensfree holograms of the objects at different viewing directions. By capturing multiple frames at each illumination angle, pixel super-resolution techniques are utilized to reconstruct high-resolution transmission images at each angle. Tomograms of flowing objects are then computed through filtered back-projection of these reconstructed lensfree images, thereby enabling optical sectioning on-a-chip. The proof-of-concept is demonstrated by lensfree tomographic imaging of C. elegans.
Wave equation on Riemannian symmetric spaces
Authors: Hassani A.
Published: April 2011

We consider the wave equation on Riemannian symmetric spaces of the noncompact type. We prove that the solutions of the homogeneous equation have dispersion properties and we deduce Strichartz-type estimates for these solutions. We use these estimates to treat nonlinear equations with power type. As a byproduct, we prove the global well-posedness for small energy.
Electrode dependence of filament formation in HfO2 resistive-switching memory
Authors: Lin Kuan-Liang , Hou Tuo-Hung , Shieh Jiann , Lin Jun-Hung , Chou Cheng-Tung , Lee Yao-Jen
Published: April 2011

This study investigates bipolar and nonpolar resistive-switching of HfO2 with various metal electrodes. Supported by convincing physical and electrical evidence, it is our contention that the composition of conducting filaments in HfO2 strongly depends upon the metal electrodes. Nonpolar resistive-switching with the Ni electrode is attributed to the migration of metal cations and the corresponding electrochemical metallization. Conversely, oxygen-deficient filaments induced by anion migration are responsible for bipolar resistive-switching. It was also found that the characteristic nature of the conducting filaments influences many aspects of switching characteristics, including the switching power, cycling variations, and retention at elevated temperatures.
Analysis of the weak coupling of the IrMn/Co/Ru/NiFe structures by ferromagnetic resonance
Authors: Alayo W. , Sousa M. A. , Pelegrini F. , Baggio-Saitovitch E.
Published: April 2011

The Ir20Mn80/Co/Ru/Ni81Fe19 spin valve structures have been produced by sputtering deposition and analyzed by ferromagnetic resonance. Two well resolved modes are identified in the FMR spectra as the resonance of the Co and NiFe layers. The in-plane angular dependence of the resonance peaks for the NiFe layer present a small asymmetry, which is attributed to the interlayer exchange interaction between ferromagnetic layers across the nonmagnetic spacer. The data were analyzed considering the exchange bias at the IrMn/Co interface and the indirect coupling between Co and NiFe. The in-plane angular dependence of the resonance fields of both Co and NiFe layers present an upward (downward) shift for antiferromagnetic (ferromagnetic) coupling with respect to a system with no interlayer coupling.
Computational comparison of conductivity and mobility models for silicon nanowire devices
Authors: Frey M. , Esposito A. , Schenk A.
Published: April 2011

In this paper, a comparison of three different models for the conductivity and mobility is given for the case of silicon nanowire devices in the presence of electron-phonon scattering. The consistency of all three models in the case of homogeneous nanowires is demonstrated. The scattering limited conductivity and mobility is a well defined quantity in this case. For nonhomogeneous systems like triple-gate nanowires FETs, these scattering limited quantities are no longer well defined for very short gate lengths. The quality of the underlying assumptions and the physical interpretation of the differences in the resulting transport characteristics are discussed.
Residual stress-dependent electric conductivity of sputtered co-doped CeO2 thin-film electrolyte
Authors: Liu Wei , Liu Hongqin , Ou Gang , Pan Wei
Published: April 2011

Sm3+ and Nd3+ co-doped ceria thin-film electrolytes have been deposited on polycrystalline alumina substrates via RF magnetron sputtering. Electric conductivity is evaluated with respect to the residual stress in the film by sin2 ψ-methodology, indicating that an in-plane tensile stress is applied to the as-deposited film. The stress in the film increases as annealing temperature decreases, and there is an enlarged crystal lattice. The results also reveal that the annealed film with a greater stress shows a higher electric conductivity, which might be due to the lower activation energy. The conductivity of the film annealed at 600 °C is as high as 0.009 S cm−1 at 500 °C, and the residual stress is determined to be 542.70 MPa at room temperature.
Iron distribution in silicon after solar cell processing: Synchrotron analysis and predictive modeling
Authors: Fenning D. P. , Hofstetter J. , Bertoni M. I. , Hudelson S. , Rinio M. , Lelièvre J. F. , Lai B. , del Cañizo C. , Buonassisi T.
Published: April 2011

The evolution during silicon solar cell processing of performance-limiting iron impurities is investigated with synchrotron-based x-ray fluorescence microscopy. We find that during industrial phosphorus diffusion, bulk precipitate dissolution is incomplete in wafers with high metal content, specifically ingot border material. Postdiffusion low-temperature annealing is not found to alter appreciably the size or spatial distribution of FeSi2 precipitates, although cell efficiency improves due to a decrease in iron interstitial concentration. Gettering simulations successfully model experiment results and suggest the efficacy of high- and low-temperature processing to reduce both precipitated and interstitial iron concentrations, respectively.
Analytical model for interaction of short intense laser pulse with solid target
Authors: Luan S. X. , Yu Wei , Yu M. Y. , Ma G. J. , Zhang Q. J. , Sheng Z. M. , Murakami M.
Published: April 2011

A simple but comprehensive two-dimensional analytical model for the interaction of a normally incident short intense laser pulse with a solid-density plasma is proposed. Electron cavitation near the target surface by the laser ponderomotive force induces a strong local electrostatic charge-separation field. The cavitation makes possible mode conversion of the laser light into longitudinal electron oscillation at laser frequency, even for initial normal incidence of laser pulse. The intense charge-separation field in the cavity can significantly enhance the laser induced u×B electron oscillation at twice laser frequency to density levels even higher than that of the initial target.
Resonance theory for discrete models: Methodology and isolated resonances
Authors: Klaiman Shachar , Hatano Naomichi
Published: April 2011

We here consider open quantum systems defined on discretized space, motivated by experimental and theoretical interest in the electronic conduction through nanoscale devices such as molecular junctions and quantum dots. We particularly focus on effects of resonances on the conductance through the systems. We develop a method of calculating the conductance with the use of Green's function expansion with respect to the eigenstates of the effective Hamiltonian for the open quantum systems. Unlike previous methodologies where one can treat only narrow resonances far from the band edges in a satisfactory manner with a Lorentzian profile, our method provides a novel resonance profile which can be used to describe any isolated resonance in the spectrum even close to the band edges.
Versatile, high sensitivity, and automatized angular dependent vectorial Kerr magnetometer for the analysis of nanostructured materials
Authors: Teixeira J. M. , Lusche R. , Ventura J. , Fermento R. , Carpinteiro F. , Araujo J. P. , Sousa J. B. , Cardoso S. , Freitas P. P.
Published: April 2011

Magneto-optical Kerr effect (MOKE) magnetometry is an indispensable, reliable, and one of the most widely used techniques for the characterization of nanostructured magnetic materials. Information, such as the magnitude of coercive fields or anisotropy strengths, can be readily obtained from MOKE measurements. We present a description of our state-of-the-art vectorial MOKE magnetometer, being an extremely versatile, accurate, and sensitivity unit with a low cost and comparatively simple setup. The unit includes focusing lenses and an automatized stepper motor stage for angular dependent measurements. The performance of the magnetometer is demonstrated by hysteresis loops of Co thin films displaying uniaxial anisotropy induced on growth, MnIr/CoFe structures exhibiting the so called exchange bias effect, spin valves, and microfabricated flux guides produced by optical lithography.
Preparation of W–Ta thin-film thermocouple on diamond anvil cell for in-situ temperature measurement under high pressure
Authors: Yang Jie , Li Ming , Zhang Honglin , Gao Chunxiao
Published: April 2011

In this paper, a W–Ta thin-film thermocouple has been integrated on a diamond anvil cell by thin-film deposition and photolithography methods. The thermocouple was calibrated and its thermal electromotive force was studied under high pressure. The results indicate that the thermal electromotive force of the thermocouple exhibits a linear relationship with temperature and is not associated with pressure. The resistivity measurement of ZnS powders under high pressure at different temperatures shows that the phase transition pressure decreases as the temperature increases.
Flip chip lamination to electrically contact organic single crystals on flexible substrates
Authors: Coll M. , Goetz K. P. , Conrad B. R. , Hacker C. A. , Gundlach D. J. , Richter C. A. , Jurchescu O. D.
Published: April 2011

The fabrication of top metal contacts for organic devices represents a challenge and has important consequences for electrical properties of such systems. We report a robust, low-cost and nondestructive printing process, flip chip lamination, to fabricate top contacts on rubrene single crystals. The use of surface chemistry treatments with fluorinated self-assembled monolayers, combined with pliable substrates, and mild nanoimprint conditions, ensures conformal contact between ultrasmooth metal contacts and the organic crystal. Space-charge limited current measurements point to better interfacial electrical properties with the flip chip lamination-fabricated contacts compared to the analog architecture of e-beam evaporated top contacts.
Improved tunneling magnetoresistance at low temperature in manganite junctions grown by molecular beam epitaxy
Authors: Werner R. , Petrov A. Yu. , Miño L. Alvarez , Kleiner R. , Koelle D. , Davidson B. A.
Published: April 2011

We report resistance versus magnetic field measurements for a La0.65Sr0.35MnO3/SrTiO3/La0.65Sr0.35MnO3 tunnel junction grown by molecular-beam epitaxy, that show a large field window of extremely high tunneling magnetoresistance (TMR) at low temperature. Scanning the in-plane applied field orientation through 360°, the TMR shows fourfold symmetry, i.e., biaxial anisotropy, aligned with the crystalline axis but not the junction geometrical long axis. The TMR reaches ∼1900% at 4 K, corresponding to an interfacial spin polarization of >95% assuming identical interfaces. These results show that uniaxial anisotropy is not necessary for large TMR, and lay the groundwork for future improvements in TMR in manganite junctions.
Composite scaffold provides a cell delivery platform for cardiovascular repair
Authors: Godier-Furnémont Amandine F. G. , Martens Timothy P. , Koeckert Michael S. , Wan Leo , Parks Jonathan , Arai Kotaro , Zhang Geping , Hudson Barry , Homma Shunichi , Vunjak-Novakovic Gordana
Published: April 2011

Control over cell engraftment, survival, and function remains critical for heart repair. We have established a tissue engineering platform for the delivery of human mesenchymal progenitor cells (MPCs) by a fully biological composite scaffold. Specifically, we developed a method for complete decellularization of human myocardium that leaves intact most elements of the extracellular matrix, as well as the underlying mechanical properties. A cell–matrix composite was constructed by applying fibrin hydrogel with suspended cells onto decellularized sheets of human myocardium. We then implanted this composite onto the infarct bed in a nude rat model of cardiac infarction. We next characterized the myogenic and vasculogenic potential of immunoselected human MPCs and demonstrated that in vitro conditioning with a low concentration of TGF-β promoted an arteriogenic profile of gene expression. When implanted by composite scaffold, preconditioned MPCs greatly enhanced vascular network formation in the infarct bed by mechanisms involving the secretion of paracrine factors, such as SDF-1, and the migration of MPCs into ischemic myocardium, but not normal myocardium. Echocardiography demonstrated the recovery of baseline levels of left ventricular systolic dimensions and contractility when MPCs were delivered via composite scaffold. This adaptable platform could be readily extended to the delivery of other reparative cells of interest and used in quantitative studies of heart repair.
Non-isomorphism invariant Borel quantifiers
Authors: Engström Fredrik , Schlicht Philipp
Published: April 2011

Every isomorphism invariant Borel subset of the space of structures on the natural numbers in a countable relational language is definable in

L

ω
1

ω

{\mathscr {L}}_{\omega _1\omega }

by a theorem of Lopez-Escobar. We derive variants of this result for stabilizer subgroups of the symmetric group

S
y
m

(

N

)

{\mathrm {Sym}}(\mathbb {N})

for families of relations and non-isomorphism invariant generalized quantifiers on the natural numbers such as “for all even numbers”. Moreover we produce a binary quantifier

Q
Q

for every closed subgroup of

S
y
m

(

N

)

{\mathrm {Sym}}(\mathbb {N})

such that the Borel sets of structures invariant under the subgroup action are exactly the sets of structures definable in

L

ω
1

ω

(
Q
)

{\mathscr {L}}_{\omega _1\omega }(Q)

.
On the derivative of the Hausdorff dimension of the quadratic Julia sets
Authors: Jaksztas Ludwik
Published: April 2011

Let

d
(
c
)

d(c)

denote the Hausdorff dimension of the Julia set

J
c

J_c

of the polynomial

f
c

(
z
)
=

z
2

+
c

f_c(z)=z^2+c

. The function

c
↦
d
(
c
)

c\mapsto d(c)

is real-analytic on the interval

(
−
3

/

4
,
1

/

4
)

(-3/4,1/4)

, which is included in the main cardioid of the Mandelbrot set. It was shown by G. Havard and M. Zinsmeister that the derivative

d
′

(
c
)

d’(c)

tends to

+
∞

+\infty

as fast as

(
1

/

4
−
c

)

d
(
1

/

4
)
−
3

/

2

(1/4-c)^{d(1/4)-3/2}

when

c
↗
1

/

4

c\nearrow 1/4

. Under numerically verified assumption

d
(
−
3

/

4
)
>
4

/

3

d(-3/4)>4/3

, we prove that

d
′

(
c
)

d’(c)

tends to

−
∞

-\infty

as

−
(
c
+
3

/

4

)

3
d
(
−
3

/

4
)

/

2
−
2

-(c+3/4)^{3d(-3/4)/2-2}

when

c
↘
−
3

/

4

c\searrow -3/4

.
Chromatin remodelers clear nucleosomes from intrinsically unfavorable sites to establish nucleosome-depleted regions at promoters
Authors: Tolkunov Denis , Zawadzki Karl A. , Singer Cara , Elfving Nils , Morozov Alexandre V. , Broach James R.
Published: April 2011

Most promoters in yeast contain a nucleosome-depleted region (NDR), but the mechanisms by which NDRs are established and maintained in vivo are currently unclear. We have examined how genome-wide nucleosome placement is altered in the absence of two distinct types of nucleosome remodeling activity. In mutants of both SNF2, which encodes the ATPase component of the Swi/Snf remodeling complex, and ASF1, which encodes a histone chaperone, distinct sets of gene promoters carry excess nucleosomes in their NDRs relative to wild-type. In snf2 mutants, excess promoter nucleosomes correlate with reduced gene expression. In both mutants, the excess nucleosomes occupy DNA sequences that are energetically less favorable for nucleosome formation, indicating that intrinsic histone–DNA interactions are not sufficient for nucleosome positioning in vivo, and that Snf2 and Asf1 promote thermodynamic equilibration of nucleosomal arrays. Cells lacking SNF2 or ASF1 still accomplish the changes in promoter nucleosome structure associated with large-scale transcriptional reprogramming. However, chromatin reorganization in the mutants is reduced in extent compared to wild-type cells, even though transcriptional changes proceed normally. In summary, active remodeling is required for distributing nucleosomes to energetically favorable positions in vivo and for reorganizing chromatin in response to changes in transcriptional activity.
A yeast model for polyalanine-expansion aggregation and toxicity
Authors: Konopka Catherine A. , Locke Melissa N. , Gallagher Pamela S. , Pham Ngan , Hart Michael P. , Walker Claire J. , Gitler Aaron D. , Gardner Richard G.
Published: April 2011

Nine human disorders result from the toxic accumulation and aggregation of proteins with expansions in their endogenous polyalanine (polyA) tracts. Given the prevalence of polyA tracts in eukaryotic proteomes, we wanted to understand the generality of polyA-expansion cytotoxicity by using yeast as a model organism. In our initial case, we expanded the polyA tract within the native yeast poly(Adenine)-binding protein Pab1 from 8A to 13A, 15A, 17A, and 20A. These expansions resulted in increasing formation of Pab1 inclusions, insolubility, and cytotoxicity that correlated with the length of the polyA expansion. Pab1 binds mRNA as part of its normal function, and disrupting RNA binding or altering cytoplasmic mRNA levels suppressed the cytotoxicity of 17A-expanded Pab1, indicating a requisite role for mRNA in Pab1 polyA-expansion toxicity. Surprisingly, neither manipulation suppressed the cytotoxicity of 20A-expanded Pab1. Thus longer expansions may have a different mechanism for toxicity. We think that this difference underscores the potential need to examine the cytotoxic mechanisms of both long and short expansions in models of expansion disorders.
Interleukin-15 regulates proliferation and self-renewal of adult neural stem cells
Authors: Gómez-Nicola Diego , Valle-Argos Beatriz , Pallas-Bazarra Noemí , Nieto-Sampedro Manuel
Published: April 2011

The impact of inflammation is crucial for the regulation of the biology of neural stem cells (NSCs). Interleukin-15 (IL-15) appears as a likely candidate for regulating neurogenesis, based on its well-known mitogenic properties. We show here that NSCs of the subventricular zone (SVZ) express IL-15, which regulates NSC proliferation, as evidenced by the study of IL-15−/− mice and the effects of acute IL-15 administration, coupled to 5-bromo-2′-deoxyuridine/5-ethynyl-2′-deoxyuridine dual-pulse labeling. Moreover, IL-15 regulates NSC differentiation, its deficiency leading to an impaired generation of neuroblasts in the SVZ–rostral migratory stream axis, recoverable through the action of exogenous IL-15. IL-15 expressed in cultured NSCs is linked to self-renewal, proliferation, and differentiation. IL-15–/– NSCs presented deficient proliferation and self-renewal, as evidenced in proliferation and colony-forming assays and the analysis of cell cycle–regulatory proteins. Moreover, IL-15–deficient NSCs were more prone to differentiate than wild-type NSCs, not affecting the cell population balance. Lack of IL-15 led to a defective activation of the JAK/STAT and ERK pathways, key for the regulation of proliferation and differentiation of NSCs. The results show that IL-15 is a key regulator of neurogenesis in the adult and is essential to understanding diseases with an inflammatory component.
Evidence for reduced selection pressure on the hepatitis B virus core gene in hepatitis B e antigen-negative chronic hepatitis B
Authors: Warner Brook G. , Tsai Peter , Rodrigo Allen G. , ‘Ofanoa Malakai , Gane Edward J. , Munn Stephen R. , Abbott William G. H.
Published: April 2011

The mechanisms underlying the high levels of hepatitis B virus (HBV) replication that cause hepatitis B e antigen (HBeAg)-negative chronic hepatitis B (e−CHB) are unknown. Impaired anti-HBV immunity, which may be measurable as a relaxation of selection pressure on the virus, is possible. A group of Tongans (n = 345) with a chronic HBV infection, including seven with e−CHB, were genotyped at HLA class I. The repertoire of HBV core-gene codons under positive selection pressure was defined by phylogenetic analysis (by using thepamlprogram) of 708 cloned sequences extracted from the 67 of these 345 subjects with the same repertoire of HLA class I alleles as the seven e−CHB individuals and matched controls (see below). The frequency of non-synonymous mutations at these codons was measured in longitudinal data from 15 subjects. Finally, the number of non-synonymous mutations at these codons was compared in seven groups comprised of one subject with e−CHB and 1–3 HLA class I-matched controls with an inactive, HBeAg-negative chronic HBV infection (e−InD). Nineteen codons in the core gene were under positive selection pressure. There was a high frequency of new non-synonymous mutations at these codons (P<0.0001) in longitudinal data. The mean number of these 19 codons with non-synonymous mutations was lower (P = 0.02) in HBV from subjects with e−CHB (4.4±0.5 codons per subject) versus those with e−InD (6.4±0.4 codons per subject). There is a subtle relaxation in selection pressure on the HBV core gene in e−CHB. This may be due to impaired antiviral immunity, and could contribute to the high levels of viral replication that cause liver inflammation in this disease.