bluuebunny/crossref_metadata_2025 huggingface dataset:
Rustic Country House to Refined Farmhouse: The Evolution and Migration of an Architectural Form
Authors: Lazzaro Claudia
Published: April 2006

This study seeks to isolate a distinctive architectural tradition of the countryside in Italy through the examination of a single building type which served, over the course of its history, as both a country house for landowners and a farmhouse for tenant farmers. The hipped-roof block with central hipped-roof belvedere, apparently the invention of Vignola, appeared as a country house in Tuscany and Latium from the 1560s through the early 18th century. The sources of this building type reside in the local traditions of the countryside, castles, and farmhouses, and in the designs for country houses by several architects from the beginning of the 16th century which classicized, but still recalled, existing rural forms. The associations with both landowners and workers made it the preferred building type for the construction of new farmhouses under the land reforms of the late 18th century. This study of the development of a country house type and the characteristics of farmhouse architecture reveals that the two building traditions repeatedly interacted and that no clear distinction between monumental and vernacular architecture can be made, but rather that buildings in the countryside shared a set of symbolic forms particular to their setting.
Frank Lloyd Wright in Moscow: June 1937
Authors: Johnson Donald Leslie
Published: April 2006

In June 1937 Frank Lloyd Wright attended the First All-Union Congress of Soviet Architects held in Moscow. His visit at the request of the Union of Soviet Architects is known mainly, in fact almost exclusively as a result of the American's own frenetic promotions, including his autobiography. The nature of his visit has not heretofore been objectively reported. As well, a paper he delivered has remained obscure in the absence of knowledge.
Joseph Hoffer and the Study of Ancient Architecture
Authors: Sisa József
Published: April 2006

Joseph Hoffer, a Hungarian-born architect trained at the Polytechnikum of Vienna, worked in the newly independent Kingdom of Greece between 1833 and 1838. In Athens he surveyed with extraordinary accuracy the buildings of the Acropolis, which led to the discovery of one of the "refinements" of ancient architecture, the curvature of the horizontal parts of Greek temples. He published his findings in the Vienna Allgemeine Bauzeitung in 1838, but for some time his achievement was ignored. John Pennethorne, an English architect, claimed to have observed this same fact first, but he published it only later. After his return from Greece, Hoffer, already a master-builder in his native Arad, was admitted to the builders' guild of Pest, but with only limited rights; in Hungary, his scholarly achievement was not appreciated.
Belluschi and the Equitable Building in History
Authors: Clausen Meredith L.
Published: April 2006

When the Equitable Building opened in 1948 in Portland, Oregon, it was recognized immediately as one of the most significant buildings of the time. Simple, spare, elegant, its concrete structural frame reduced to a minimum and further dematerialized by a shimmering aluminum skin, it filled the image of the transparent, metal-and-glass skyscraper, the first to realize the Miesian dream. With it, Belluschi culminated the development of the Chicago frame, synthesizing Sullivan's legacy with the aspirations of the future and transforming the old, masonry-clad, historicizing, prewar high-rise into the new, sleek, prismatic slab of the postwar era. The building marked a pivotal moment in the history of Modernism. The basic concept of the Equitable was, however, conceived well before the end of the war. The story of this landmark building provides a revealing glimpse into the processes of history-what buildings are recorded, how they achieve their fame, and how their reputations are sustained or lost.
H. H. Richardson: The Design of the William Watts Sherman House
Authors: Ochsner Jeffrey Karl , Hubka Thomas C.
Published: April 2006

Henry Hobson Richardson's design for the William Watts Sherman house, in Newport, Rhode Island, has long been considered an anomaly among his projects. While its living hall plan has always been credited to Richardson, the exterior has often been thought to have been the work of Richardson's assistant, Stanford White, drawing on the published work of Richard Norman Shaw. Study of surviving sketches, drawings, and other records, along with an examination of the house itself, shows that this explanation of the Sherman house is inadequate. Not only did Richardson control both plan and massing, but he must also be credited with the design of critical front gable, which did not derive from Shaw's work. Analysis of Richardson's sketches also offers clues to Richardson's typical architectural design method and compositional approach, as well as to his specific blending of English, Continental, and especially American colonial vernacular influences in the Sherman design. These influences also provide a basis for understanding why the house became such an important source for the development of multiple themes in American domestic architecture in succeeding decades, especially the Shingle Style.
Recent Excavations under the "Ombrellone" of Sant'Andrea in Mantua: Preliminary Report
Authors: Saalman Howard , Ghirardini Livio Volpi , Law Anthony
Published: April 2006

Recent excavations have revealed the existence of an integrated complex of vaulted rooms, stairs, and passages under the so-called ombrellone of the western portico of Sant'Andrea in Mantua. The authors suggest that this complex and its adjacent rooms may have been intended to serve for the exposition of the relics of the Most Precious Blood of Christ, preserved in Sant'Andrea, possibly in times of danger and plague, and for the guardian brotherhood of the relics, the Venerable Company of the Most Precious Blood, established in Sant'Andrea by Pius II in 1462. The adjacent rooms over the first side chapels of the nave may have served for "ritual habitation" by members of the ruling Gonzaga family, particularly for the patron, the marchese Ludovico Gonzaga.
Structural Innovation and Structural Design in Renaissance Architecture
Authors: Betts Richard J.
Published: April 2006

The characteristic structural forms of large Renaissance churches-domes, drums, pendentives, and barrel vaults-were the products of innovation in theory and practice during the later fifteenth century in Italy that culminated in Bramante's projects for the new Saint Peter's. Significant ideas were contributed by Leon Battista Alberti, Francesco di Giorgio, and Leonardo da Vinci. Francesco di Giorgio's geometrical methods of design for churches as described in his second treatise incorporate a procedure for calculating the thickness of walls bearing vaults. Francesco di Giorgio tested the procedure in his own churches, and it was later used by Bramante.
Speaking of Architecture: The Evolution of a Vocabulary in Vasari, Jones, and Sir John Vanbrugh
Authors: Cast David
Published: April 2006

The reading Jones gave to the books he owned could serve him in various ways. This article is concerned with one such use he made of the materials in the Vite by Giorgio Vasari, one volume of which we know he possessed and on which he made notes. It is suggested that this text gave him an opportunity to construct a critical vocabulary for architecture, different in character from that available to him from such sources as Palladio, Vitruvius, or Serlio. And it is also suggested that this new vocabulary is specifically reflected in two passages about architecture, and in what J. A. Gotch called Jones' sentiments about architecture, written in the notebook now at Chatsworth. In addition, this article is concerned with the development of a more general vocabulary in England in the seventeenth century, for gentlemen and architects alike, that came from the tradition of praise, or epideixis, together with terms of a more particular kind to refer to the parts of architecture that came both from Italian and French.
Frank Lloyd Wright's Guggenheim Museum: A Historian's Report
Authors: Quinan Jack
Published: April 2006

This is the first of a series of occasional reports that will focus on special problems related to major works of world architecture. In these reports, scholar-experts will be asked to give an account of the state of a work of architecture or a historical problem. In this report, Jack Quinan views Frank Lloyd Wright's Guggenheim Museum in relation to the new addition by Gwathmey Siegel and in the context of Wright's career as a whole. Quinan shows how the spiral was rooted within Wright's consciousness from his earliest education in Unitarianism and transcendentalism. The spiral represented the geometric shape of utmost importance to Wright, one which he frequently tried to include in his architectural designs. Quinan argues that the Gwathmey Siegel slab represents an unsympathetic response to Wright's greatest spiraling form, the Guggenheim Museum.
Richardson's Web: A Client's Assessment of the Architect's Home and Studio
Authors: Molloy Mary Alice
Published: April 2006

John Jacob Glessner appears to have been the only person outside Henry Hobson Richardson's circle of friends and employees to have written a detailed account of his experiences visiting the architect's home and office in Brookline, Mass. Glessner's account documents the interrelationship between house and work spaces in Richardson's career and details the ways in which Richardson used both places to urge his client to accept his ideas for a proposed residence in Chicago. Richardson died believing he had convinced Glessner of the rightness of all of his proposals. Glessner's second thoughts, however, resulted in one serious deviation from the architect's intentions.
The Vernacular, Modernism, and Le Corbusier
Authors: Passanti Francesco
Published: April 2006

The modernist architecture of the 1920s, often referred to by the terms "machine aesthetic" and "International Style," has been seen as antithetical to the vernacular. Focusing on Le Corbusier, this essay argues that, to the contrary, the vernacular played an essential role in the construction of modernist architecture, as conceptual model for a notion of modern vernacular-one as naturally the issue of modern industrial society, and as representative of it, as the traditional vernacular of common parlance had been of earlier societies. Le Corbusier arrived at this notion by layering on each other several discourses concerning regionalism, folklore, and the more complex concept of Sachlichkeit (factualness), developed in Vienna and Germany at the turn of the century by such figures as Adolf Loos and Hermann Muthesius.
Reformation to Millennium: Pugin's Contrasts in the History of English Thought
Authors: Hill Rosemary
Published: April 2006

Pugin's Contrasts of 1836 was the book that marked the turning point of the Gothic Revival and the end of the Georgian age. It also launched its author's career as an apologist for the moral and religious value of architecture. The much modified second edition of 1841 has assumed a greater importance for historians. It was the first edition, however, that impressed contemporaries and made Pugin's name. This essay looks at the process by which the book as it appeared in 1836 was composed, including the first, previously unpublished, scheme of 1833. It also examines its social and intellectual context. It suggest that Contrasts marked the meeting of two currents of thought in which Pugin had been steeped since childhood: the English antiquarian tradition, which was, from the Reformation itself, deeply imbued with Catholic sympathy, and the Romantic millenarianism of the 1830s, which determined the form that Contrasts eventually took. It also suggests that Pugin's early life, his contact with the theories of the Picturesque, with the theater and popular journalism, as well as the influence of his mother, all played a greater part than has been thought in the composition of Contrasts.
On the Idea of the Mandala as a Governing Device in Indian Architectural Tradition
Authors: Bafna Sonit
Published: April 2006

This paper is an attempt to reconsider our current understanding of the role accorded to the mandala within traditional Indian architecture. It is generally held that the mandala-in particular the Vāstupuruṣamaṇḍala, the mandala associated with vāstu (inhabited or built site)-has played a determining role in the genesis of architectural form in India. Within more popular, and less circumspect, writings, this influence is held to be directly formal; the Vāstupuruṣamaṇḍala is traditionally drawn within a square grid, and any sign of an orthogonal planning or a grid-like layout is taken to be a sign that the form in question was based upon the mandala. In investigating the foundations of such a belief, this paper reviews two bodies of literature. The first is modern art-historical scholarship, an examination of which shows that the idea of a morphogenetic mandala emerged only recently, and that it was not so much culled from the traditional writing as constructed afresh by art historians such as Kramrisch. The other body of literature examined is that of the traditional writings on architecture, many of which are cited as key sources of evidence for this idea. Here it is argued that there is almost no direct evidence for the use of mandalas in laying out complexes or designing buildings, and that such ideas of the use of mandalas rest on several assumptions that must themselves be questioned.
Jacopo Sansovino, Giacomo Torelli, and the Theatricality of the Piazzetta in Venice
Authors: Johnson Eugene J.
Published: April 2006

The architectural forms of Jacopo Sansovino's Libreria di San Marco in Venice, begun in 1537, have generally been interpreted in terms of a revival of the ancient Roman forum. Another way of looking at the building, suggested here, concentrates on its theatrical nature, both in terms of the typology of architectural forms and in terms of use. Sansovino's library completed the Piazzetta in Venice as a theatrical space, and it did so at the same time that the modern theater with boxes was first developed in Venice. The great seventeenth-century scene designer Giacomo Torelli in turn used the space completed by Sansovino as a set for the opera Bellerofonte, produced in Venice in 1642. In Torelli's scene, Venice is shown as a theater of justice.
Inside Front Cover: Three‐Dimensionally Ordered Gold Nanocrystal/Silica Superlattice Thin Films Synthesized via Sol–Gel Self‐Assembly (Adv. Funct. Mater. 7/2006)
Authors: Fan H. , Wright A. , Gabaldon J. , Rodriguez A. , Brinker C. J. , Jiang Y.‐B.
Published: April 2006

The synthesis of three‐dimensionally ordered, transparent gold‐nanocrystal (NC)/silica superlattice thin films using the self‐assembly (by spin‐coating) of water‐soluble gold nanocrystal micelles and soluble silica is reported by Fan and co‐workers on p. 891. The robust, 3D NC/silica superlattice films are of interest for the development of collective optical and electronic phenomena, and, importantly, for the integration of NC arrays into device architectures.

Nanocrystals and their ordered arrays hold many important applications in fields such as catalysis, surface‐enhanced Raman spectroscopy based sensors, memory storage, and electronic and optical nanodevices. Herein, a simple and general method to synthesize ordered, three‐dimensional, transparent gold nanocrystal/silica superlattice thin films by self‐assembly of gold nanocrystal micelles with silica or organosilsesquioxane by spin‐coating is reported. The self‐assembly process is conducted under acidic sol–gel conditions (ca. pH 2), ensuring spin‐solution homogeneity and stability and facilitating the formation of ordered and transparent gold nanocrystal/silica films. The monodisperse nanocrystals are organized within inorganic host matrices as a face‐centered cubic mesostructure, and characterized by transmission electron spectroscopy and X‐ray diffraction.
Synthesis and Antimicrobial Screening of 5H,7H‐N‐(Coumarin‐6‐yl) ‐2,8‐diphenyl‐5,7‐dioxo‐4,5,6,7‐tetrahydrobenzimidazo[5,6‐c]furan and 5H,7H‐N‐(Coumarin‐6‐yl)‐2,8‐diphenyl‐5,7‐dioxo‐6‐ (7‐methoxy‐4‐methylcoumarin‐6‐yl)‐4,5,6,7‐tetrahydrobenzimidazo [5,6‐c]pyrrole.
Authors: Choudhari B. P. , Mulwad V. V.
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Skeletal Modification of a Non‐Planar Phthalocyanine Analogue under Very Mild Conditions.
Authors: Fukuda Takamitsu , Ogi Yusuke , Kobayashi Nagao
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Design and Synthesis of Nanostructured Catalysts
Authors: Ying Jackie Y.
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Palladium‐Catalyzed Reactions on 1,2‐Diazines
Authors: Maes Bert U. W. , Tapolcsanyi Pal , Meyers Caroline , Matyus Peter
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Catalysis by Homo‐ and Heteronuclear Polymetallic Systems
Authors: Moiseev I. I. , Gekhman A. E. , Tsodikov M. V. , Kugel V. Ya. , Yandieva F. A. , Glebov L. S. , Kliger G. Yu. , Mikaya A. I. , Zaikin V. G. , Maksimov Yu. V. , et al. et al.
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Chemical Synthesis of Nucleoside 5′‐Triphosphate
Authors: Vaghefi Morteza M.
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis of Optically Pure 1,4‐Dioxanes from Alkenes Promoted by Organoselenium Reagents
Authors: Tiecco M. , Testaferri L. , Marini F. , Sternativo S. , Santi C. , Bagnoli L. , Temperini A.
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
In Search of Simplicity and Flexibility: A Rational Access to Twelve Fluoroindolecarboxylic Acids
Authors: Schlosser Manfred , Ginanneschi Assunta , Leroux Frédéric
Published: April 2006

All twelve indolecarboxylic acids 1–12 carrying both a fluorine substituent and a carboxy group at the benzo ring have been prepared either directly from the corresponding fluoroindoles 13–16 or from the chlorinated derivatives 22, 23 and 25 by hydrogen/metal permutation (“metalation”), or from the bromo‐ or iodofluoroindoles 17–20 and 26, 27, 29 and 30 by halogen/metal permutation, the organometallic intermediate being each time trapped with carbon dioxide. In most, though not all cases, the nitrogen atom in the five‐membered ring had to be protected by a trialkylsilyl group. Some of the bromo‐ or iodofluoroindoles (26 and 27) were successfully subjected to a basicity gradient‐driven selective migration of the heavy halogen. An unexpected finding on the way to the target compounds were the rigorously site‐selective metalation of the 5‐fluoro‐N‐(trialkylsilyl)indole (14b; exclusive deprotonation of the 4‐position). The fluoroindoles 13–16, although previously known, were accessed more conveniently from suitably substituted nitrobenzenes using the Bartoli or the Leimgruber–Batcho method. A new and very attractive indole synthesis was elaborated consisting of the ortho‐lithiation of an N‐acyl‐protected aniline followed by ortho‐formylation, Wittig chloromethylenation and base‐catalyzed cyclization accompanied by dehydrochlorination. These five consecutive steps can be contracted to a convenient one‐pot protocol.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Amplitude propagation in slowly varying trains of shear-flow instability waves
Authors: Russell J. M.
Published: April 2006

The analog of Whitham's law of conservation of wave action density is derived in the case of Rayleigh instability waves. The analysis allows for wave propagation in two space dimensions, non-unidirectionality of the background flow velocity profiles and weak horizontal nonuniformity and unsteadiness of those profiles. The small disturbance equations of motion in the Eulerian flow description are subject to a change of dependent variable in which the new variable represents the pressure-driven part of a disturbance material coordinate function as a function of the Cartesian spatial coordinates and time. Several variational principles expressing the physics of the small disturbance equations of motion are presented in terms of this new variable. A law of conservation of ‘bilinear wave action density’ is derived by a method intermediate between those of Jimenez and Whitham (1976) and Hayes (1970a). The distinction between the observed square amplitude of an amplified wavetrain and the wave action density is discussed. Three types of algebraic focusing are discussed, the first being the far-field ‘caustics’, the second being near-field ‘movable singularities’, and the third being a focusing mechanism due to Landahl (1972) which we here derive under somewhat weaker hypotheses.
Geoffrey Ingram Taylor, 7 March 1886–27 June 1975
Authors: Batchelor G. K.
Published: April 2006

G. I. Taylor was a happy man who spent a long life doing what he wanted most to do and doing it supremely well. He was a natural scientist whose character and activities were perfectly matched, and that allowed the fullest use of his creative talents. This short article is intended to help the understanding of G. I. Taylor's approach to his research by providing some information about the man and his life, in particular the major events in his early adult years which determined the direction of much of his subsequent research. A list of the now rather numerous articles about the man and his family and his work is appended.
Vortex excitation of prisms with elongated rectangular, H and [vdash ] cross-sections
Authors: Nakamura Yasuharu , Nakashima Masamichi
Published: April 2006

This is an experimental investigation of vortex excitation of prisms with elongated rectangular, H- and [vdash ]-shaped cross-sections, where the depth parallel to the flow is much greater than the height perpendicular to the flow. Measurements are made of free oscillations in a wind tunnel and flow visualizations in a water tank. The flow around elongated bluff prisms is dominated by the impinging-shear- layer instability where the separated shear layers become unstable in the presence of different kinds of shape of the rear part of the cross-section, which may include sharp trailing edges. The two unstable shear layers interact with each other when they meet together downstream of the prism, thereby forming Kármán vortices with the same frequency of oscillation. The former impinging-shear-layer instability is largely responsible for vortex excitation of elongated bluff prisms.
Simultaneous flow visualization and Reynolds-stress measurement in a turbulent boundary layer
Authors: Talmon A. M. , Kunen J. M. G. , Ooms G.
Published: April 2006

Flow visualization and Reynolds-stress measurement were combined in an investigation of a turbulent boundary layer in a water channel. Hydrogen bubbles were used to visualize the flow; a laser-Doppler anemometer capable of measuring two velocity components was applied to measure the instantaneous value of the Reynolds stress. Owing to the three-dimensional, time-dependent character of the flow it was rather difficult to identify flow structures from measured velocity signals, especially at larger distances from the wall. Despite this difficulty a method based on the instantaneous value of the Reynolds stress could be developed for detecting bursts in the wall region of the boundary layer. By this method the three-dimensional, time-dependent character of the flow is taken into account by attributing to the same burst ejections occurring successively with very short time intervals. This identification procedure is based on a comparison on a one-to-one basis between visualized flow structures and measured values of the Reynolds stress. The detected bursts were found to make a considerable contribution to the momentum transport in the boundary layer.
Ordered and chaotic vortex streets behind circular cylinders at low Reynolds numbers
Authors: Atta C. W. Van , Gharib M.
Published: April 2006

We report some experiments undertaken to investigate the origin of ordered and chaotic laminar vortex streets behind circular cylinders at low Reynolds numbers. We made simultaneous measurements of near wake longitudinal velocity and cylinder lateral vibration amplitude spectra for cylinder Reynolds numbers in the range from 40 to 160. For a non-vibrating cylinder the velocity energy spectra contained only a single peak, at the Strouhal frequency. When the cylinder was observed to vibrate in response to forcing by the vortex wake, additional dominant spectral peaks appeared in the resulting ‘ordered’ velocity spectra. Cylinder vibrations too small to be noticed with the naked eye or from audible Aeolian tones produced a coupled wake-cylinder response with dramatic effects in hot-wire and cylinder vibration detector signals. The velocity spectra associated with these coupled motions had dominant peaks at the Strouhal frequency fs, at a frequency fc proportional to the fundamental cylinder vibration frequency, and at sum and difference combinations of multiples of fs and fc. In windows of chaos the velocity spectra were broadened by switching between different competing coupling modes. The velocity spectra were very sensitive to the nature of the boundary conditions at the ends of the cylinder. Our measurements strongly suggest that the very similar regions of ‘order’ and ‘chaos’ observed by Sreenivasan and interpreted by him as transition through quasi-periodic states in the sense of the Ruelle, Takens, and Newhouse theory were also due to aeroelastic coupling of the vortex wake with cylinder vibration modes.
Large-scale vortex structures in turbulent wakes behind bluff bodies. Part 1. Vortex formation processes
Authors: Perry A. E. , Steiner T. R.
Published: April 2006

An investigation of turbulent wakes was conducted and phase-averaged velocity vector fields are presented, as well as phase-averaged and global Reynolds normal and shear stresses. The topology of the phase-averaged velocity fields is discussed in terms of critical point theory. Here in Part 1, the vortex formation process in the cavity region of several nominally two-dimensional bluff bodies is investigated and described using phase-averaged streamlines where the measurements were made in a nominal plane of symmetry. It was found that the flows encountered were always three-dimensional and that the mean-flow patterns in the cavity region were quite different from those expected using classical two-dimensional assumptions.
Timescale and structure of ejections and bursts in turbulent channel flows
Authors: Luchik T. S. , Tiederman W. G.
Published: April 2006

Burst structures in the near wall region of turbulent flows are associated with a large portion of the turbulent momentum transport from the wall. However, quantitative measures of the timescales associated with the burst event are not well defined, largely due to ambiguities associated with the methods used to detect a burst.

In the present study, Eulerian burst-detection schemes were developed through extensions of the uv quadrant 2, VITA, and u-level techniques. Each of the basic techniques detects ejections. One or more ejections are contained in each burst and hence the key idea is to identify and to group those ejections from a single burst into a single-burst detection. When the ejection detections were grouped appropriately into burst detections, all of the extended techniques yielded the same average time between bursts as deduced from flow visualization for fully-developed channel flow in the range 8700 [les ] Reh [les ] 17 800. The present results show that inner variables (wall shear stress and kinematic viscosity) are the best candidates for the proper scaling of the average time between bursts. Conditional velocity sampling during burst and ejection detections shows that these burst events are closely correlated with slower-than-average moving fluid, moving both away from the wall and toward the wall.
The nonlinear growth of a gravitationally unstable interface in a Hele-Shaw cell
Authors: Maxworthy T.
Published: April 2006

We report observations of the nonlinear growth of an unstable interface in, a large Hele-Shaw cell in which it is possible, in the most extreme case, to follow the emergence of a single ‘finger’ from approximately thirty initial wavelets. The larger ‘fingers’ that emerge undergo further instability to form a highly contorted interface. We have measured a number of the averaged characteristics of this interface and can relate the various cases studied through length and time scales constructed from the independent parameters of the problem. We show that the most distorted interfaces may have a fractal dimension at scales larger than the instability wavelength and discuss the significance of this possibility.
On nonlinear K-l and K-ε models of turbulence
Authors: Speziale Charles G.
Published: April 2006

The commonly used linear K-l and K-ε models of turbulence are shown to be incapable of accurately predicting turbulent flows where the normal Reynolds stresses play an important role. By means of an asymptotic expansion, nonlinear K-l and K-ε models are obtained which, unlike all such previous nonlinear models, satisfy both realizability and the necessary invariance requirements. Calculations are presented which demonstrate that this nonlinear model is able to predict the normal Reynolds stresses in turbulent channel flow much more accurately than the linear model. Furthermore, the nonlinear model is shown to be capable of predicting turbulent secondary flows in non-circular ducts - a phenomenon which the linear models are fundamentally unable to describe. An additional application of this model to the improved prediction of separated flows is discussed briefly along with other possible avenues of future research.
Velocity and vorticity distributions in periodic separating laminar flow
Authors: Mathioulakis D. S. , Telionis D. P.
Published: April 2006

Steady and unsteady velocity components over a backward-facing circular arc are measured by laser-Doppler velocimetry. A periodic disturbance is added to the mean flow and the response of unsteady separation is investigated. Special attention is given to the distribution and the flux of vorticity.
The spreading of oil on water in the surface-tension regime
Authors: Camp David W. , Berg John C.
Published: April 2006

Data which describe the unidirectional spreading of several pure oils and oilsurfactant mixtures on water in the surface-tension regime are reported. Leadingedge position and profiles of velocity, thickness and film tension are given as functions of time. The data are consistent with the numerical similarity solution of Foda & Cox (1980), although the measured dependence of the film tension on the film thickness often differs from the equilibrium relationship. The configuration of the oil film near the spreading origin may be either a coherent multimolecular layer or a multitude of thinning, outward-moving lenses surrounded by monolayer. The pure oils show an acceleration zone connecting the slow-moving inner region to a fast-moving outer region, while the oil-surfactant mixtures show a much more gradual increase in film velocity.
Mechanisms for the generation of edge waves over a sloping beach
Authors: Evans D. V.
Published: April 2006

Two mechanisms for the generation of standing edge waves over a sloping beach are described using classical linear water-wave theory. The first is an extension of the result of Yih (1984) to a class of localized bottom protrusions on a sloping beach in the presence of a longshore current. The second is a class of longshore surface-pressure distributions over a beach. In both cases it is shown that Ursell-type standing edge-wave modes can be generated in an appropriate frame of reference. Typical curves of the mode shapes are presented and it is shown how in certain circumstances the dominant mode is not the lowest.
Surface waves due to resonant horizontal oscillation
Authors: Funakoshi M. , Inoue S.
Published: April 2006

Experiments on surface waves were made using a cylindrical container oscillated horizontally with the period T close to that associated with the two known degenerate modes. Outside a certain region in the (T,x0)-plane, where x0 is the amplitude of the forcing displacement, surface waves exhibit either of the two kinds of regular motions whose amplitudes are constant. Within this region, however, the wave amplitude slowly changes, expressing the irregular or periodic motion of surface waves. In order to analyse these motions in detail, the slow evolution of four variables associated with the amplitudes and phases of the two modes is computed from the free-surface displacement at two measuring points. It is shown that the most common attractor corresponding to the irregular wave motion is the strange attractor with a positive maximum Liapunov exponent and a correlation dimension of 2.1–2.4. Furthermore, another kind of chaotic attractor and a few periodic orbits are found in a small parametric region. The route to chaos associated with period-doubling bifurcation is also observed. The above experimental results are compared with the solutions to weakly nonlinear evolution equations derived by Miles. We find that the equations can explain well many of the experimental results on regular and irregular wave motions. In particular, the most common chaotic attractors both in the experiments and in the theory have similar shapes in a phase space, and also yield similar values for maximum Liapunov exponents and correlation dimensions.
Thickness noise of a propeller and its relation to blade sweep
Authors: Amiet R. K.
Published: April 2006

Linearized acoustic theory is applied to the calculation of the thickness noise produced by a supersonic propeller with sharp leading and trailing edges. The theoretical development is summarized and numerical calculations of the pressure-time waveform are presented. The erratic behaviour of previous time-domain calculations has been completely eliminated by careful numerical treatment of singular points, multiple singular points and nearly singular points that appear in the analysis. This allows a close inspection of the details of the calculated waveform and leads to the discovery of abrupt changes of slope in the pressure-time waveform, produced by singular points entering or leaving the blade at the tip. The behaviour of the pressure-time waveform is shown to be closely related to changes in the retarded rotor shape. Logarithmic singularities in the waveform are shown to be produced by regions on the blade edges that move towards the observer at sonic speed while at the same time having the edge normal to the line joining the source point and the observer. The logarithmic singularities are closely related to the shock waves produced by a swept airfoil in supersonic rectilinear motion, and they can be eliminated throughout the entire flow field by sweeping the rotor so that the Mach-number component normal to the leading and trailing edges is subsonic for all points on the rotor edges.
Vindication of mode-coupled descriptions of multiple-scale water wave fields
Authors: Brueckner Keith A. , West Bruce J.
Published: April 2006

Herein we show that the modal description of deep-water waves on the sea surface Watson & West 1975) is independent of any reference surface around which expansions of the velocity potential and the surface velocity are done. We demonstrate by direct construction that the interaction between long and short waves does not lead to divergent terms in the equations of motion when this formalism is used.
Substructures in a turbulent spot
Authors: Sankaran R. , Sokolov M. , Antonia R. A.
Published: April 2006

Substructures within a turbulent spot which develops in a slightly heated laminar boundary layer have been identified using arrays of cold wires aligned in either a streamwise direction or in a direction normal to the wall. At any given streamwise distance from the spot origin, histograms of the number of detected substructures exhibit a peak, defining the most probable spot or the spot with the most likely number of substructures. The number of substructures in the most probable spot increases with streamwise distance but all substructures are convected at approximately the same velocity for any given distance from the wall. This velocity is approximately equal to that of the leading edge of the spot and increases slightly with distance from the wall. The increase in the number of substructures accounts for the streamwise growth of the spot. A simple relation is derived for determining the number of substructures at a particular streamwise station and a geometrical construction is proposed for identifying the origin of a new substructure. There is sufficient evidence for suggesting that the new substructures are formed near the trailing edge of the spot. The convection velocity, inclination and lengthscales of the substructures compare favourably with the corresponding characteristics of hairpin vortices.
The Bury Psalter and the descendants of Edward the Exile
Authors: Rushforth Rebecca
Published: April 2006

The Bury Psalter (Rome, Biblioteca Apostolica Vaticana, Reg. lat. 12) is
a famously beautiful copy of the Psalms with marginal line-drawings,
made probably at Bury St Edmunds, and certainly for its use. Rebecca
Rushforth discussses two hexametrical obits added to the calendar in the
early twelfth century, and identifies them as referring to two
descendants of the royal Anglo-Saxon House of Wessex: Christina,
daughter of Edward the Exile; and her nephew Edgar king of Scotland (d.
1107), son of St Margaret and Malcolm Canmore.
The role of fluid wall association on adsorption of chain molecules at functionalized surfaces: A density functional approach
Authors: Tscheliessnig R. , Billes W. , Fischer J. , Sokołowski S. , Pizio O.
Published: April 2006

We present a density functional theory to describe adsorption in systems where selected segments of chain molecules of fluids can bond (or associate) with functional groups attached to the surfaces. Association of active segments with the surface is modeled within the framework of the first-order thermodynamic perturbation theory. We discuss the influence of several parameters such as the density of surface active sites, the energy of association, the chain length, and the number of the active segment in the chain molecule on the structure of the fluid adjacent to the wall. The proposed model can be considered as a first step towards developing a density functional theory of molecular brushes chemically bonded to solid surfaces.
Evolution of bacteriophages infecting encapsulated bacteria: lessons from Escherichia coli K1‐specific phages
Authors: Stummeyer Katharina , Schwarzer David , Claus Heike , Vogel Ulrich , Gerardy‐Schahn Rita , Mühlenhoff Martina
Published: April 2006

Bacterial capsules are not only important virulence factors, but also provide attachment sites for bacteriophages that possess capsule degrading enzymes as tailspike proteins. To gain insight into the evolution of these specialized viruses, we studied a panel of tailed phages specific for Escherichia coli K1, a neuroinvasive pathogen with a polysialic acid capsule. Genome sequencing of two lytic K1‐phages and comparative analyses including a K1‐prophage revealed that K1‐phages did not evolve from a common ancestor. By contrast, each phage is related to a different progenitor type, namely T7‐, SP6‐, and P22‐like phages, and gained new host specificity by horizontal uptake of an endosialidase gene. The new tailspikes emerged by combining endosialidase domains with the capsid binding module of the respective ancestor. For SP6‐like phages, we identified a degenerated tailspike protein which now acts as versatile adaptor protein interconnecting tail and newly acquired tailspikes and demonstrate that this adapter utilizes an N‐terminal undecapeptide interface to bind otherwise unrelated tailspikes. Combining biochemical and sequence analyses with available structural data, we provide new molecular insight into basic mechanisms that allow changes in host specificity while a conserved head and tail architecture is maintained. Thereby, the present study contributes not only to an improved understanding of phage evolution and host‐range extension but may also facilitate the on purpose design of therapeutic phages based on well‐characterized template phages.
Exclusive enteral feeding as primary therapy for Crohn’s disease in Australian children and adolescents: A feasible and effective approach
Authors: Day Andrew S , Whitten Kylie E , Lemberg Daniel A , Clarkson Cathy , Vitug‐Sales Maribel , Jackson Reuben , Bohane Tim D
Published: April 2006

Background:  Exclusive enteral feeding has been shown to be as efficacious as corticosteroids in inducing remission in children with Crohn’s disease (CD), with additional nutritional benefits. The use of polymeric formulae provides superior palatability and acceptance over elemental feeds, but polymeric formulae have not been universally adopted. The present retrospective analysis of enteral feeding in children with Crohn’s disease aims to demonstrate the short‐term benefits of enteral feeding in children upon disease activity and nutrition parameters.

Methods:  The case records of children with CD managed with exclusive enteral nutrition (EEN) by a multidisciplinary team over a 2‐year period were reviewed. Data relating to therapy, background disease details, and outcome were collated. Primary outcome measures established were weight change and disease activity (Pediatric Crohn’s Disease Activity Index: PCDAI).

Results:  Twenty‐seven children received EEN with polymeric formulae. Fifteen children had newly diagnosed CD and 12 had known long‐standing CD. Twenty‐four children completed the prescribed period of EEN. Twelve of 15 (80%) newly diagnosed CD and seven of 12 (58%) with long‐standing disease entered remission. Children with newly diagnosed CD responding to EEN took all feeds orally and gained an average of 4.7 ± 3.5 kg with mean PCDAI decreasing from 37.1 ± 10.8 to 6.7 ± 5.1 after 8 weeks. In addition, four children continued supplementary polymeric formula (without other medical therapies) and all have maintained remission during an average follow‐up period of 15.2 months.

Conclusion:  Exclusive enteral feeds induced remission in 80% of children with newly diagnosed CD (on intention‐to‐treat basis) when used as sole initial therapy while also improving nutritional status. All newly diagnosed children treated with EEN, who were able to establish feeds, achieved remission. In addition, remission may be prolonged with oral supplementary formula as sole ongoing treatment. Further study of the role(s) of enteral feeds and of longer‐term benefits of enteral feeding in children with CD is now required.
Activity of fin muscles and fin motoneurons during swimming motor pattern in the lamprey
Authors: Mentel Tim , Krause Alexander , Pabst Milan , El Manira Abdeljabbar , Büschges Ansgar
Published: April 2006

Coordination of motoneuron activity is a fundamental prerequisite for the generation of functional locomotor patterns. We investigate the neural mechanisms that coordinate activity of motoneuron pools in the vertebrate spinal cord with differing phases of activity in the locomotor cycle in a simple motor system, the lamprey swimming network. In the region of dorsal fins the lamprey spinal cord contains two groups of motoneurons: the myotomal motoneurons that innervate the trunk muscles; and the fin motoneurons controlling muscle fibres of the dorsal fins. We investigated the activity of fin muscles during swimming in vivo and that of fin motoneurons during fictive swimming in vitro. During swimming in vivo with cycle periods of 4–8 Hz, fin muscle activity covered a broad portion of the cycle, with the peak of activity out‐of‐phase to the ipsilateral myotomal muscles. During fictive swimming evoked by N‐methyl‐d‐aspartate in the isolated spinal cord, fin motoneurons expressed similar out‐of‐phase activity. The phase relationship of the synaptic drive to fin motoneurons was examined by recording their activity intracellular during fictive swimming. Three different forms of membrane potential oscillation with different time courses in the locomotor cycle could be distinguished. Sagittal lesions of the spinal cord in the segment where fin motoneurons are recorded and up to one segment rostral and caudal from it did not influence the out‐of‐phase activity pattern of the motoneurons. Our results indicate that coordination of fin motoneuron activity with the locomotor activity of myotomal motoneurons does not depend on intrasegmental contralateral premotor elements.
Patterns of bushmeat hunting and perceptions of disease risk among central African communities
Authors: LeBreton M. , Prosser A.T. , Tamoufe U. , Sateren W. , Mpoudi‐Ngole E. , Diffo J. L. D. , Burke D. S. , Wolfe N. D.
Published: April 2006

There is a great need to determine the factors that influence the hunting, butchering and eating of bushmeat to better manage the important social, public health and conservation consequences of these activities. In particular, the hunting and butchering of wild animals can lead to the transmission of diseases that have potentially serious consequences for exposed people and their communities. Comprehension of these risks may lead to decreased levels of these activities. To investigate these issues, 3971 questionnaires were completed to examine the determinants of the hunting, butchering and eating of wild animals and perceptions of disease risk in 17 rural central African villages. A high proportion of individuals reported perceiving a risk of disease infection with bushmeat contact. Individuals who perceived risk were significantly less likely to butcher wild animals than those who perceived no risk. However, perception of risk was not associated with hunting and eating bushmeat (activities that, compared with butchering, involve less contact with raw blood and body fluids). This suggests that some individuals may act on perceived risk to avoid higher risk activity. These findings reinforce the notion that conservation programs in rural villages in central Africa should include health‐risk education. This has the potential to reduce the levels of use of wild animals, particularly of certain endangered species (e.g. many non‐human primates) that pose a particular risk to human health. However, as the use of wild game is likely to continue, people should be encouraged to undertake hunting and butchering more safely for their own and their community's health.