bluuebunny/crossref_metadata_2025 huggingface dataset:
Aquila's Bible Translation in Late Antiquity: Jewish and Christian Perspectives
Authors: Labendz Jenny R.
Published: July 2009

In the early or mid-second century c.e., a Jewish proselyte named Aquila1 translated the Hebrew Bible into Greek.2 The translation survives today only in fragments, but both Jewish and Christian sources from Late Antiquity offer perspectives on and information about Aquila as well as citations of his translation. To fully understand the role his legacy played in Jewish and Christian communities requires careful analysis of each of the sources. I believe that prior scholarship, especially regarding ancient perspectives on Aquila and his translation, as well as the popularity of his translation in various communities, has drawn conclusions based on overall impressions of texts that may appear quite differently when examined closely and in context. My goal in the following pages is to develop a more nuanced understanding of the history of Aquila's Bible translation in Late Antiquity.
Radiological balloon dilatation of post-treatment benign pharyngeal strictures
Authors: Williams L R , Kasir D , Penny S , Homer J J , Laasch H-U
Published: July 2009

Aims:

To assess the technical success, clinical outcomes and complications of radiologically guided balloon dilatation of benign strictures developing after treatment for head and neck cancer.

Materials and methods:

Forty-six balloon dilatations were performed in 20 patients. All dilatations were performed over a guidewire.

Results:

Technical success was 100 per cent. Fifteen of the 20 patients demonstrated clinical improvement in dysphagia scores. Improvement in dysphagia was temporary in all patients (median 102 days), with multiple dilatations usually required (total dilatations ranged from one to seven). Immediate complications were encountered in six of the 46 (13 per cent) dilatations and were all minor. Late complications occurred after two procedures (4 per cent): localised perforation (later complicated by secondary infection) and recurrence of a previous, small, pharyngo-cutaneous fistula.

Conclusion:

Radiologically guided balloon dilatation is straightforward to perform and is well tolerated, but there is a small risk of perforation. Relief of symptoms is likely to be temporary, requiring multiple subsequent dilatations. A minority of patients will obtain no symptomatic relief.
A summative, Objective, Structured, Clinical Examination in ENT used to assess postgraduate doctors after one year of ENT training, as part of the Diploma of Otorhinolaryngology, Head and Neck Surgery
Authors: Drake-Lee A B , Skinner D , Hawthorne M , Clarke R ,   and the Examiners for the Diploma of Otorhinolaryngology, Head and Neck Surgery
Published: July 2009

Context:

‘High stakes’ postgraduate medical examinations should conform to current educational standards. In the UK and Ireland, national assessments in surgery are devised and managed through the examination structure of the Royal Colleges of Surgeons. Their efforts are not reported in the medical education literature. In the current paper, we aim to clarify this process.

Objectives:

To replace the clinical section of the Diploma of Otorhinolaryngology with an Objective, Structured, Clinical Examination, and to set the level of the assessment at one year of postgraduate training in the specialty.

Methods:

After ‘blueprinting’ against the whole curriculum, an Objective, Structured, Clinical Examination comprising 25 stations was divided into six clinical stations and 19 other stations exploring written case histories, instruments, test results, written communication skills and interpretation skills. The pass mark was set using a modified borderline method and other methods, and statistical analysis of the results was performed.

Results:

The results of nine examinations between May 2004 and May 2008 are presented. The pass mark varied between 68 and 82 per cent. Internal consistency was good, with a Cronbach's α value of 0.99 for all examinations and split-half statistics varying from 0.96 to 0.99. Different standard settings gave similar pass marks.

Conclusions:

We have developed a summative, Objective, Structured, Clinical Examination for doctors training in otorhinolaryngology, reported herein. The objectives and standards of setting a high quality assessment were met.
Inverted papilloma with osteogenesis in the anterior ethmoid and frontal sinuses
Authors: Tsuzuki K , Nishigami T , Takebayashi H , Sakaguchi A , Oka H , Fukazawa K , Sakagami M
Published: July 2009

Objective:

We report a rare case of new bone formation (osteogenesis) within an inverted papilloma, occurring in the ethmoid and frontal sinuses.

Method:

The histopathological and radiological findings, differential diagnosis, and treatment of tumour-induced osteogenesis are discussed.

Results:

A 68-year-old man complained of headache and left-sided, purulent rhinorrhoea of five years' duration. On nasal endoscopy, lesions similar to inflammatory nasal polyps were seen. Pre-operative radiological images demonstrated opacification of the left nasal cavity and anterior ethmoid and frontal sinuses, plus a bone-density lesion. The mass with bony lesion was completely removed endoscopically. The mass was histopathologically diagnosed as an inverted papilloma surrounding bony tissue. Furthermore, the histopathological findings (including immature bony tissue rimmed by osteoblasts) indicated an extremely rare case of inverted papilloma induced osteogenesis. Six months after surgery, no recurrence was detected.

Conclusion:

This case highlights the importance of clinical awareness of tumour-induced osteogenesis.
Osteoradionecrosis of tympanic bone: reconstruction of outer ear canal with pedicled skin flap, combined with hyperbaric oxygen therapy, in five patients
Authors: Metselaar M , Dumans A G , van der Huls M P C , Sterk W , Feenstra L
Published: July 2009

Objective:

To evaluate the results of one-stage surgical repair of the meatal skin defect in patients with long-lasting osteoradionecrosis of the outer ear canal, using a postauricular, inferiorly pedicled skin flap. All patients were also treated with hyperbaric oxygen both pre- and post-operatively.

Methods:

A prospective study evaluating the results of a one-stage surgical procedure to repair the meatal skin defect in five patients with osteoradionecrosis of the outer ear canal. All patients were treated with hyperbaric oxygen both pre- and post-operatively.

Results:

In four of the five patients, intact canal skin was achieved after surgery and hyperbaric oxygen therapy. One patient needed a second operation to cover a small remaining area of bare bone. In one patient, wound healing was unsatisfactory and an area of bare bone remained.

Conclusion:

In cases of osteoradionecrosis of the outer ear canal, the skin defect can be repaired with an inferiorly pedicled skin flap. Although not yet scientifically proven, the peri-operative application of hyperbaric oxygen may be of additional value to improve wound healing in areas of compromised tissue.
Solutions for the two-phase Stefan problem with the Gibbs–Thomson Law for the melting temperature
Authors: Luckhaus Stephan
Published: July 2009

The coupling of the Stefan equation for the heat flow with the Gibbs–Thomson law relating the melting temperature to the mean curvature of the phase interface is considered. Solutions, global in time, are constructed which satisfy the natural a priori estimates. Mathematically the main difficulty is to prove a certain regularity in time for the temperature and the indicator function of the phase separately. A capacity type estimate is used to give an L1 bound for fractional time derivatives.
Models of elastic–perfectly plastic materials
Authors: Greenberg J. M.
Published: July 2009

This note deals with a new model of elastic–perfectly plastic materials in which the yield stress is regarded as a threshold above which plastic flow occurs rather than a constraint which cannot be violated. This modelling change allows us to treat a number of signalling and impact problems not solvable within the classic framework of elastic–perfectly plastic materials.
Phosphorus diffusion in silicon
Authors: King J. R.
Published: July 2009

Phosphorus diffusion in silicon shows a number of anomalous effects, and we apply asymptotic methods to a model problem which includes most of these. Both constant surface concentration problems and the diffusion of implanted dopant are considered. An unusual feature of the model is the non-local dependence of the tail diffusivity on the peak concentration.
Symmetry-based algorithms to relate partial differential equations: II. Linearization by nonlocal symmetries
Authors: Bluman G. W. , Kumei S.
Published: July 2009

An algorithm is presented to linearize nonlinear partial differential equations by non-invertible mappings. The algorithm depends on finding nonlocal symmetries of the given equations which are realized as appropriate local symmetries of a related auxiliary system. Examples include the Hopf-Cole transformation and the linearizations of a nonlinear heat conduction equation, a nonlinear telegraph equation, and the Thomas equations.
On a two-phase continuous casting Stefan problem with nonlinear flux
Authors: Rodrigues José Francisco , Yi Fahuai
Published: July 2009

We prove the existence of a weak solution for a two-phase continuous casting Stefan problem with a general monotone nonlinear cooling condition. We establish a sufficient condition for stability, which yields uniqueness and comparison results for the evolutionary and the steady- state solutions. We also discuss the asymptotic behaviour as t←∞ of the corresponding temperatures and enthalpies.
On the correctness of a model for phase transitions in binary alloys
Authors: Götz I. G.
Published: July 2009

The main result of this paper is a non-uniqueness theorem for the self-similar solutions of a model for phase transitions in binary alloys. The reason for this non-uniqueness is the discontinuity in the coefficients of heat conduction and diffusion at the inter-phase. Also the existence of a self-similar solution and the stability criterion are discussed.
Diffraction of sound by a surface scratch on an elastic solid
Authors: Howe M. S.
Published: July 2009

An analysis is made of the diffraction of sound by a scratch (or groove) in the nominally plane surface of a fluid-loaded elastic solid. The solid is modelled as an isotropic half-space, and an exact representation of the diffracted sound is obtained as an integral over the surface of the scratch involving a Green's function and the acoustic field for the homogeneous solid. The restriction of the range of integration to the surface of the scratch permits the use of an approximate form of Green's function which is valid for source positions confined to a limited region of space. Details are worked out for the case in which the acoustic wavelength is much larger than the diameter of the scratch cross-section (Rayleigh approximation). The results are illustrated by application to sound waves in water inicident on a rectilinear scratch of circular cross-section in steel or rubber. In the former case an important rôle in diffraction is played by leaky Rayleigh waves on the fluid-solid interface.
Coronas and the space charge problem
Authors: Budd Chris
Published: July 2009

This paper presents a detailed analysis of a model for a positive corona discharge, and discusses the relationship between the model and the space charge equations which predict the macroscopic motion of charged ions in a gas. The study is restricted to the asymptotic behaviour of the discharge for large time, and it does not consider its initial or burst phases in detail.

One prediction of this model is the existence of a steady state solution to the space charge equations that may lose stability to a travelling wave disturbance which then grows into a strongly pulsed oscillation.

We compare some numerical calculations with an asymptotic analysis of the discharge and find good agreement.
Global solutions in one-dimensional magneto-thermoviscoelasticity
Authors: Sprekels Jürgen
Published: July 2009

Global smooth solutions are shown to exist for the system governing magneto-thermoviscoelastic phenomena in an electrically and thermally conducting isotropic solid immersed in an electromagnetic field. It is assumed that displacement currents are negligible, and that all field quantities depend on one space variable only; Joule heating is included.
Explicit Galoisian solutions in anisotropic elasticity
Authors: Head A. K.
Published: July 2009

A practical method is given that can determine whether or not it is possible for all or part of a problem in crystal elasticity to be expressed in explicit rational or radical terms when the characteristic sextic polynomial is known to be unsolvable. It involves the determination of the group to which an elastic quantity (displacement, stress, strain, energy density) belongs under permutations of the roots of the sextic polynomial. If this is not the symmetric group then a rational or radical expression is impossible. It is applied to the three-dimensional problem of a point force (the Green's function) in a cubic crystal. It is proved that it is impossible that the Green's function could be given by any radical expression that is valid for all elastic constants and directions in the crystal, as the existence of such an expression would lead to the solution of a proven unsolvable polynomial. It follows that the rational expression given by Dikici (1986) for the Green's function is not just incorrect, but that it is impossible that there could be any such rational expression. The same impossibility is found to apply to the displacements, stresses and strains of a straight dislocation in a cubic crystal. The application to other elasticity problems is discussed.
The Cahn–Hilliard gradient theory for phase separation with non-smooth free energy Part I: Mathematical analysis
Authors: Blowey J. F. , Elliott C. M.
Published: July 2009

A mathematical analysis is carried out for the Cahn–Hilliard equation where the free energy takes the form of a double well potential function with infinite walls. Existence and uniqueness are proved for a weak formulation of the problem which possesses a Lyapunov functional. Regularity results are presented for the weak formulation, and consideration is given to the asymptotic behaviour as the time becomes infinite. An investigation of the associated stationary problem is undertaken proving the existence of a nontrivial stationary solution and further regularity results for any stationary solution. Stationary solutions are constructed in one and two dimensions; a formula for the number of stationary solutions in one dimension is derived. It is then natural to study the asymptotic behaviour as the phenomenological parameter λ→0, the main result being that the interface between the two phases has minimal area.
Vector hysteresis models
Authors: Krejčí Pavel
Published: July 2009

Following Krasnoselskii & Pokrovskii (1983) we express the constitutive law for the Prandtl–Reuss elastoplastic model in terms of a hysteresis operator, and introduce the vector Ishlinskii model. We investigate some properties (continuity, energy inequalities, dependence on spatial variables) of these operators.
Algorithms for reducing a system of PDEs to standard form, determining the dimension of its solution space and calculating its Taylor series solution
Authors: Reid Gregory J.
Published: July 2009

We present several algorithms, executable in a finite number of steps, which have been implemented in the symbolic language maple. The standard form algorithm reduces a system of PDEs to a simplified standard form which has all of its integrability conditions satisfied (i.e. is involutive). The initial data algorithm uses a system's standard form to calculate a set of initial data that uniquely determines a local solution to the system without needing to solve the system. The number of arbitrary constants and arbitrary functions in the general solution to the system is directly calculable from this set. The taylor algorithm uses a system's standard form and initial data set to determine the Taylor series expansion of its solution about any point to any given finite degree. All systems of linear PDEs and many systems of nonlinear PDEs can be reduced to standard form in a finite number of steps. Our algorithms have simple geometric interpretations which are illustrated through the use of diagrams. The standard form algorithm is generally more efficient than the classical methods due to Janet and Cartan for reducing systems of PDEs to involutive form.
Young measures and the absence of fine microstructures in a class of phase transitions
Authors: Matos João Palhoto
Published: July 2009

It is shown that for a class of pairs of energy wells the only Young measures having these wells as support must reduce to spatially constant Dirac masses. This implies the prediction that fine structures will be absent in certain crystal phase transitions.
On the pulsating instability of two-dimensional flames
Authors: Pereira Carlos Alvarez , Vega José M.
Published: July 2009

We consider a well-known thermo-diffusive model for the propagation of a premixed, adiabatic flame front in the large-activation-energy limit. That model depends only on one nondimensional parameter β, the reduced Lewis number. Near the pulsating instability limit, as β↓β0= 32/3, we obtain an asymptotic model for the evolution of a quasi-planar flame front, via a multi-scale analysis. The asymptotic model consists of two complex Ginzburg–Landau equations and a real Burgers equation, coupled by non-local terms. The model is used to analyse the nonlinear stability of the flame front.
Two-dimensional slow viscous flows with time-dependent free boundaries driven by surface tension
Authors: Richardson S.
Published: July 2009

We consider the two-dimensional quasi-steady Stokes flow of an incompressible Newtonian fluid occupying a time-dependent simply-connected region bounded by a free surface. The motion is driven by a constant surface tension acting at the free boundary so that, with the effects of gravity ignored, one expects the boundary to approach a circular form as time evolves. It is shown that, if at some initial instant the region occupied by the fluid is given by a rational conformal map of the unit disc, then it must retain this property as long as the region remains simply-connected. Moreover, its evolution may be described analytically; in simple cases this description is explicit, but in more complicated problems the numerical integration of a system of first order differential equations may be required.
Symmetrization of interface dynamics equations
Authors: Antanovskii Leonid K.
Published: July 2009

The system of conservation laws governing heat and mass transfer processes in a continuous medium is obtained in a symmetric form on the basis of the successive application of fundamental thermodynamic principles. This approach involves reformulating the problem in intensive thermodynamic variables such as the temperature and chemical potential. The equations of capillary fluid mechanics and phase transitions with moving free boundaries are analysed in detail. The unsteady motion of a drop driven by buoyancy forces in an unbounded ambient fluid with dilute surfactants is investigated where the LeChatelier principle is established for an arbitrary surfactant. The general procedure for construction of self-similar solutions for the thermodiffusive Stefan problem with piecewise constant matrices of coefficients is described
The semilinear heat equation with a Heaviside source term
Authors: Gianni Roberto , Hulshof Josephus
Published: July 2009

We consider the initial value problem for the equationut=uxx+H(u), whereHis the Heaviside graph, on a bounded interval with Dirichlet boundary conditions, and discuss existence, regularity and uniqueness of solutions and interfaces.
Transnational Hindu law adoptions: recognition and treatment in Britain
Authors: Shah Prakash
Published: July 2009

This article examines how the adoption of children under Hindu law in India is regarded by British private international law and immigration law. Through an analysis of case-law, it focuses particularly on how British judges regard the legitimacy of exclusion by the British immigration control system of children who have been adopted under a ‘foreign’ legal system which essentially permits private adoption arrangements. Examining the background to the regime of Indian Hindu law adoptions (which applies to Sikhs as well as Hindus), and the private international law and immigration rules which apply to such adoptees in the UK, the article finds some evidence in the judicial decisions of a more activist, human-rights-based, plurality-conscious position being taken. However, tracking the case-law further, the article concludes that such activism has not been followed through in more recent decisions leaving the conflictual position between transnational adopters and British legal systems largely unresolved.
The prejudices of Mary Hays
Authors: Ward Ian
Published: July 2009

During the 1790s, Mary Hays was one of the most influential radical novelists and polemicists in England. She counted amongst her closest friends and mentors the likes of Joseph Johnson, William Godwin and Mary Wollstonecraft. During this tumultuous final decade of the century, she published two novels,The Memoirs of Emma CourtneyandThe Victim of Prejudice. Both were controversial in the extreme, attracting the opprobrium of conservative critics. What caused such consternation was not merely their vivid description of the myriad political and social injustices suffered by her female compatriots, but the role of the law in perpetuating such injustices. For much of the last two hundred years Hays has been a largely forgotten figure, her novels occasioning rare interest amongst literary critics and historians, rarer interest still amongst jurists. The purpose of this article is to address this neglect, and to recommend Hays as one of the most intriguing and urgent prophets of modern literary and jurisprudential feminism.
Ice‐ocean processes over the continental shelf of the southern Weddell Sea, Antarctica: A review
Authors: Nicholls Keith W. , Østerhus Svein , Makinson Keith , Gammelsrød Tor , Fahrbach Eberhard
Published: July 2009

Interactions between the Southern Ocean and the Weddell Sea ice shelves are important both to the Antarctic Ice Sheet and to the production of globally significant water masses. Here we review the interaction between the Filchner‐Ronne Ice Shelf and the shelf sea in which it floats. The continental shelf processes leading to the production of Weddell Sea deep and bottom waters from the original off‐shelf source waters are discussed, and a new view is offered of the initial production of High‐Salinity Shelf Water. Data from ship‐based measurements at the ice front, from glaciological methods, and from measurements made within the sub–ice shelf cavity itself are used to describe the pattern of flows beneath the ice shelf. We also consider the variability observed within the cavity from tidal to interannual time scales and finish with a discussion of future research priorities in the region.
Hydrohalite in cold sea ice: Laboratory observations of single crystals, surface accumulations, and migration rates under a temperature gradient, with application to “Snowball Earth”
Authors: Light Bonnie , Brandt Richard E. , Warren Stephen G.
Published: July 2009

When NaCl precipitates out of a saturated solution, it forms anhydrous crystals of halite at temperatures above +0.11°C, but at temperatures below this threshold it instead precipitates as the dihydrate “hydrohalite,” NaCl · 2H2O. When sea ice is cooled, hydrohalite begins to precipitate within brine inclusions at about −23°C. In this work, hydrohalite crystals are examined in laboratory experiments: their formation, their shape, and their response to warming and desiccation. Sublimation of a sea ice surface at low temperature leaves a lag deposit of hydrohalite, which has the character of a fine powder. The precipitation of hydrohalite in brine inclusions raises the albedo of sea ice, and the subsequent formation of a surface accumulation further raises the albedo. Although these processes have limited climatic importance on the modern Earth, they would have been important in determining the surface types present in regions of net sublimation on the tropical ocean in the cold phase of a Snowball Earth event. However, brine inclusions in sea ice migrate downward to warmer ice, so whether salt can accumulate on the surface depends on the relative rates of sublimation and migration. The migration rates are measured in a laboratory experiment at temperatures from −2°C to −32°C; the migration appears to be too slow to prevent formation of a salt crust on Snowball Earth.
Rock‐and‐soil avalanches: Theory and simulation
Authors: Taboada Alfredo , Estrada Nicolas
Published: July 2009

We present a 2‐D Contact Dynamics discrete element model for simulating initiation and motion of rock avalanches, integrating hillslope geometry, Mohr‐Coulomb rock behavior, pore pressure before avalanche triggering, and avalanche trigger. Avalanche motion is modeled as a dense granular flow of dry frictional and cohesive particles. On the basis of granular physics and shear experiments, we review some of the theories for the unexpectedly long runout of rock avalanches. Different causes are evoked, according to the strength (strong or weak) of the slip surface relative to the bulk. “Mechanical fluidization” and “acoustic fluidization” theories state that agitation of rock particles reduces frictional strength, increasing runout. Conversely, granular mechanics suggests that, as “shear‐strain” rate increases, granular material becomes more agitated, more dissipative, and more resistant. Another theory states that dynamic fragmentation of clasts creates an isotropic pressure that drives longer runout. In contrast, granular mechanics suggests that fragmentation may induce fluidization and strengthening of the granular material, while particle size reduction (among others) induces weakening of the granular flow and enhances long runout. Runout is also enhanced for column‐like rock masses collapsing from steep hillslopes. Long runout may also be linked to thermal weakening mechanisms at the slip surface (e.g., thermal pressurization, and shear melting), which may lower drastically the shear strength. The model is illustrated with a hypothetical example of a rain‐triggered avalanche, mobilizing shallowly dipping layers. Several phases are identified, including slope failure, avalanche triggering resulting from slip weakening, and avalanche motion in which rocks are folded and sheared.
Probability density functions for advective‐reactive transport with uncertain reaction rates
Authors: Tartakovsky Daniel M. , Dentz Marco , Lichtner Peter C.
Published: July 2009

We derive probability density functions for advective transport of a solute that undergoes a heterogeneous chemical reaction involving an aqueous solution reacting with a solid phase. This enables us to quantify uncertainty associated with spatially varying reaction rate constants for both linear and nonlinear kinetic rate laws. While many standard techniques for uncertainty quantification in groundwater hydrology yield only concentration's mean and variance, the proposed approach leads to its full probabilistic description. This allows one to compute so‐called rare events (distribution tails), which are required in modern probabilistic risk analyses. We also compute an effective (apparent and upscaled) kinetic rate constant, a parameter that enters transport equations governing the spatiotemporal evolution of mean concentration. We demonstrate that the effective kinetic rate of nonlinear reactions is time‐dependent. This behavior provides a possible explanation for the observed discrepancy between laboratory‐measured rate constants on uniform grain sizes and measurements in natural systems where the grain size distributions are heterogeneous.
Ground‐based thermal imaging of groundwater flow processes at the seepage face
Authors: Deitchman Richard S. , Loheide Steven P.
Published: July 2009

There is no existing method to quantitatively image groundwater processes along a seepage face. Thus, it is often difficult to quantify the magnitude and spatial variability of groundwater flux. The objective of this work is to assess the use of ground‐based thermal remote sensing for fine‐scale mapping of groundwater discharge and for locating the water table position along a stream bank seepage face. Seepage faces are poorly understood and often neglected in regional hydrologic studies though they likely exert significant influence on hydrologic and ecologic processes in riparian zones. Although the importance of riparian areas is broadly recognized, our ability to quantify hydrologic, ecologic and biogeochemical processes and ecosystem services is hampered by our inability to characterize spatially variable processes such as groundwater discharge. This work employs a new, transferable, non‐invasive method that uses heat as a natural tracer to image spatially‐variable groundwater flow processes and distinguish between focused and diffuse groundwater discharge to the surface. We report, for the first time, that thermal remote sensing of groundwater at the seepage face provides indirect imaging of both the saturated zone‐unsaturated zone transition and groundwater flux at the centimeter scale, offering insight into flow heterogeneity.
Why is the stability of the Agulhas Current geographically bi‐modal?
Authors: Paldor N. , Lutjeharms J. R. E.
Published: July 2009

The Agulhas Current, the largest western boundary current of the southern hemisphere, becomes fully constituted along the eastern coast of South Africa at about 25°S, from where is flows poleward along this coast. South of the continent it retroflects with most of its water being returned to the Indian Ocean in the Agulhas Return Current whereas the rest is injected into the South Atlantic by the shedding of Agulhas Rings at the retroflection point of the current. The flow of the Agulhas Current between its initiation and retroflection points can be divided into two distinct segments by trajectorial characteristics: a northern and a southern Agulhas Current. The path of the northern Current is exceptionally stable, whereas the southern Current meanders in a way more characteristic of western boundary currents. By applying a two‐layer, linear, stability theory that specifically considers the effect of a lateral boundary (i.e. the shelf‐break) on the stability of an adjacent current flowing parallel to it, we show that the stability of the northern Current is attributable to its proximity to the African land mass, which is located only one tenth of the internal radius of deformation west of the current. By comparison, the southern Current on average flows at a distance of over nine‐tenths of the internal radius of deformation from the shelf break, where according to the theory the instability is over twice that of the northern Current.
Slow jet plume due to submarine groundwater discharge
Authors: Kinoshita Tsuguki , Tabeta Shigeru , Tanabe Nao
Published: July 2009

Ocean coastal zones are eutrophicated by fertilizer loading from agricultural activity. Contaminant loading occurs not only from rivers but also from groundwater. Recent studies have found that patterns of seaweed growth in groundwater discharge areas differ from those in other areas. We studied the behavior of groundwater discharged from the sea bottom into ocean currents by both conducting a hydraulics experiment to simulate groundwater discharge, and mathematically modeling the rising trajectory of water discharged with low velocity into a constant horizontal background flow. Both approaches showed that, due to turbulence of the horizontal background flow, low velocity discharged water flows first along the sea bottom, then follows a gently rising trajectory. This result is helpful to know the influence of submarine groundwater discharge on marine ecosystem.
On the size distribution of Atlantic tropical cyclones
Authors: Dean L. , Emanuel K. A. , Chavas D. R.
Published: July 2009

The size of a tropical cyclone is known to vary considerably across storms, though little is understood about the environmental and internal factors that modulate it. Making use of newly available extended tropical cyclone records that include information about storm structure, we examine the size distribution of Atlantic tropical cyclones, using as a metric the radius of vanishing storm winds normalized by the theoretical upper bound given by the ratio of the potential intensity to the Coriolis parameter. We find that the distribution of this normalized outer radius is closely log‐normal.
Nonlocal symmetries and integrable ordinary differential equations: ẍ+3xẋ+x3= and its generalizations
Authors: Karasu (Kalkanlı) A. , Leach P. G. L.
Published: July 2009

The equation ẍ+3xẋ+x3=0 is well known in many areas of mathematics and physics. It possesses the algebra sl(3,R) of Lie point symmetries, hence is equivalent to the equation for a free particle, and both left and right Painlevé series. We investigate two higher-dimensional analogs in terms of their symmetry and singularity structures. We find a drastic reduction in symmetry and a loss of some of the singularity properties. From the nonlocal symmetries we are able to determine the complete symmetry group as being represented by a five-dimensional Abelian algebra.
Measurement of charge distribution in actin bundles by surface potential microscopy
Authors: Zhang Peng , Cantiello Horacio F.
Published: July 2009

Bundles of filamentous actin (F-actin) deposited on a gold-plated surface were concurrently imaged using atomic force microscopy (AFM) and surface potential microscopy (SPM). The surface potential was mapped as a function of tip distance to surface using a constant bias potential. There was an uneven spatial distribution of charges detected by SPM, consistent with the segmented topological features shown by AFM of the actin bundles. SPM analysis showed localized changes in surface potential between the axial and transversal sections of the bundles, which are consistent with nonuniform charge distributions of adsorbed salt ions on F-actin.
Correlation between defect density and current leakage in InAs∕GaAs quantum dot-in-well structures
Authors: Sanchez A. M. , Beanland R. , Hasbullah N. F. , Hopkinson M. , David J. P. R.
Published: July 2009

We present a study of InAs∕GaAs quantum dot-in-well (DWELL) material using transmission electron microscopy and leakage current-voltage measurements. The spacer layers between the DWELL layers have a variety of annealing and growth temperatures. We show that there is a strong correlation between spacer layer, annealing temperature, defect density, and these leakage currents, with the most defective sample having 30 times more defects and a leakage current several orders of magnitude above that of the least defective. Cross section transmission electron microscope (TEM) shows that surface roughness above defective dots is responsible for the high defect densities. However, even in the best sample the reverse bias leakage current is several orders of magnitude above that typically seen in quantum well materials and a measurable density of defective dots are observed in planar view TEM.
CdTe nanoparticles synthesized by laser ablation
Authors: Semaltianos N. G. , Logothetidis S. , Perrie W. , Romani S. , Potter R. J. , Sharp M. , Dearden G. , Watkins K. G.
Published: July 2009

Nanoparticle generation by laser ablation of a solid target in a liquid environment is an easy, fast, and “green” method for a large scale production of nanomaterials with tailored properties. In this letter we report the synthesis of CdTe nanoparticles by femtosecond laser [387 nm, 180 fs, 1 kHz, pulse energy=6 μJ (fluence=1.7 J/cm2)] ablation of the target material. Nanoparticles with diameters from ∼2 up to ∼25 nm were observed to be formed in the colloidal solution. Their size distribution follows the log-normal function with a statistical median diameter of ≈7.1 nm. Their crystal structure is the same as that of the bulk material (cubic zincblende) and they are slightly Cd-rich (Cd:Te percentage ratio ∼1:0.9). Photoluminescence emission from the produced nanoparticles was detected in the deep red (∼652 nm).
Network of hydrogen bonds in Pro-Ala-Pro and Pro-Phe-Pro diamides: A first principles study of Ala→Phe point mutation in proline environment
Authors: Wang Hui , Csizmadia Imre G. , Marsi Istvan , Chasse Gregory A. , Fang DeCai , Viskolcz Bela
Published: July 2009

Intramolecular hydrogen bonding in the Pro-Ala-Pro and Pro-Phe-Pro tripeptides has been characterized using Bader’s atoms in molecule (AIM) analyses of relevant electron density topologies. The properties of hydrogen bonds with corresponding ring strains were investigated. Good correlations along the decrease in electron densities at ring critical points were examined from five- to ten-membered hydrogen-bound ring sizes; seven-membered rings being the most energetically favored. AIM analysis confirms the logical conclusion that the molecule has to become very compact to form as many hydrogen bonds as possible. The relatively large hydrogen bond stabilization attributed to the pronounced network of interactions comes at the “energetic expense” of a relatively large internal repulsion due to the compactness of the structures. The net balanced result was a very modest increase in the zero point corrected conformation energy (ΔEZPEC). These findings aid in establishing hydrogen bonding rules in reductionist “bottoms-up” approaches to peptide and protein folding.
Recrystallization under electromigration of a solder alloy
Authors: Kuo Shih-Ming , Lin Kwang-Lung
Published: July 2009

Electromigration induces the flux of metal elements and causes separation of the elements in an alloy. Electromigration also possibly induces the recrystallization of metal. Nevertheless, no experimental evidence has been reported for such recrystallization behavior. We report the observation of recrystallization of dispersed Zn second phases in Sn–9Zn alloy. The Zn polycrystal of aged Sn–9Zn alloy recrystallizes under electromigration to form a thin prism sheet crystal of basal plane unit with (0001) preferred orientation.
Stochastic description of the light scattered by a polydisperse colloidal suspension: Simulation and experiment
Authors: Roldán-Vargas Sándalo , Quesada-Pérez Manuel , Callejas-Fernández José
Published: July 2009

In this work, the stochastic properties of the detected signal in dynamic light scattering experiments are examined in light of Doob’s theorem. For Markovian observations of the Brownian particle position, we prove from this theorem that the electric field scattered by a polydisperse suspension can be accounted for by a linear combination of Ornstein–Uhlenbeck processes. A new algorithm for generating the fluctuating field scattered by a polydisperse system is proposed from this alternative formalism. The statistics of our synthetic data is compared satisfactorily with that resulting from the experimental signal scattered by a binary suspension of polystyrene microspheres.
Coupled photonic crystal nanobeam cavities
Authors: Deotare Parag B. , McCutcheon Murray W. , Frank Ian W. , Khan Mughees , Lončar Marko
Published: July 2009

We describe the design, fabrication, and spectroscopy of coupled, high quality (Q) factor silicon nanobeam photonic crystal cavities. We show that the single nanobeam cavity modes are coupled into even and odd superposition modes, and we simulate the frequency and Q factor as a function of nanobeam spacing, demonstrating that a differential wavelength shift of 70 nm between the two modes is possible while maintaining Q factors greater than 106. For both on substrate and freestanding nanobeams, we experimentally monitor the response of the even mode as the gap is varied, and measure Q factors as high as 2×105.
Improvements on a gravity-driven low-rate particle feeder
Authors: Wan Shaolong , Chen Wei-Yin , Gowan George
Published: July 2009

A gravity-driven particle feeder has been modified to achieve sustained operation at steady rates. Particle reservoirs and rod for controlling the nozzle opening are completely redesigned. Particle attrition and rod wobbling are the two main contributors to the feed instabilities. They, in turn, are affected by the height of the particle bed, particle contact time with the moving rod, strength of the magnetic field, and the weight, shape, and position of the rod in the magnetic field. A secondary reservoir minimizes the residence time of particles in the main reservoir. Its shape, orientation, and connection with the main reservoir have profound influences on the feeding stabilities. Tests have been conducted with particles of different types, sizes, and feed rates; results showed good long-term and short-term stabilities.
Influence of sputter rate and crystal orientation on the distribution of carbon in polycrystalline copper surfaces treated by plasma immersion ion implantation
Authors: Flege S. , Kraft G. , Bruder E. , Baba K. , Hatada R. , Ensinger W.
Published: July 2009

The sputter rate influences the resulting thickness of the carbon containing layer within a surface that was treated by plasma immersion ion implantation. Choosing a polycrystalline substrate with rather large crystals and a material with an inherent high sputter rate, inhomogeneous distributions of carbon over the substrate area due to different thicknesses of the incorporated carbon can be detected. A correlation of three factors namely the carbon x-ray intensity in electron probe microanalysis, the thickness of the carbon layer, and the sputter rate in depth profiling measurements via secondary ion mass spectrometry can be shown. Essential for these factors is the crystal orientation that is visualized by mapping via electron backscatter diffraction. The differences in carbon content due to the orientation are most likely one of the reasons that the adhesion of diamond-like carbon films on copper does not improve with an interlayer of implanted carbon.
Model based atomic resolution tomography
Authors: Saghi Zineb , Xu Xiaojing , Möbus Günter
Published: July 2009

Electron tomography is a valuable three-dimensional characterization method, but the technique has so far been limited to a nanometer scale resolution, and therefore complementary two-dimensional structural analysis is generally performed using other techniques. In this paper, computer simulations of the latest transmission electron microscope technologies are performed on a CeO2 supercell to investigate the extension of electron tomography to the atomic scale resolution, from a tilt series of high resolution electron microscopy (HREM) images. We showed that high-voltage and aberration-corrected microscopes were both capable of retrieving adjacent oxygen and Ce atoms for a thickness up to 2.5 nm. In the case where only a few tilt angle projections are in zone-axis orientations, we introduced a hybrid tomography method, whereby a lattice-resolved tomogram obtained from a few zone-axis projections is combined with the external shape reconstruction of the crystal from binary projections. Finally, we discussed some experimental challenges related to the proposed HREM tomography technique.
Band structure design and photocatalytic activity of In2O3/N–InNbO4 composite
Authors: Lv Jun , Kako Tetsuya , Zou Zhigang , Ye Jinhua
Published: July 2009

In this study, the band structure of In2O3/N–InNbO4 composite was considered to be advantageous for the transportation and separation of photoexcited electron/hole pairs. This composite was synthesized and characterized by powder x-ray diffraction, UV-visible diffuse reflectance spectroscopy, transmission electron microscope, and x-ray photoelectrons spectroscopy. The photocatalytic experiments indicated the H2 evolution rate of In2O3/N–InNbO4 composite was 27.3 μmol h−1 g−1 under visible light irradiation (λ>420 nm), which was 18.6 times the rate of In2O3 and 2.3 times the rate of N–InNbO4.
Hole diffusion profile in a p-p+ silicon homojunction determined by terahertz and midinfrared spectroscopic ellipsometry
Authors: Hofmann T. , Herzinger C. M. , Tiwald T. E. , Woollam J. A. , Schubert M.
Published: July 2009

Noninvasive optical measurement of hole diffusion profiles in p-p+ silicon homojunction is reported by ellipsometry in the terahertz (0.2–1.5 THz) and midinfrared (9–50 THz) spectral regions. In the terahertz region a surface-guided wave resonance with transverse-electrical polarization is observed at the boundary of the p-p+ homojunction, and which is found to be extremely sensitive to the low-doped p-type carrier concentration as well as to the hole diffusion profile within the p-p+ homojunction. Effective mass approximations allow determination of homojunction hole concentrations as p=2.9×1015 cm−3, p+=5.6×1018 cm−3, and diffusion time constant Dt=7.7×10−3 μm2, in agreement with previous electrical investigations.
Mechanism of strain relaxation by twisted nanocolumns revealed in AlGaN/GaN heterostructures
Authors: Kladko V. P. , Kuchuk A. V. , Safryuk N. V. , Machulin V. F. , Belyaev A. E. , Hardtdegen H. , Vitusevich S. A.
Published: July 2009

The structural properties of AlGaN/GaN heterostructures grown by metal organic chemical vapor deposition on sapphire substrates with different thicknesses were studied by high-resolution x-ray diffraction. The relation between the deformations and dislocation densities in the layer and substrate was established. The dependence of the system’s curvature on the lattice mismatch, caused by different fractions of nanoblock twists with respect to the c-plane, was determined. A mechanism of elastic strain relaxation was proposed.
Nonlinear electromagnetic wave equations for superdense magnetized plasmas
Authors: Shukla Nitin , Brodin G. , Marklund M. , Shukla P. K. , Stenflo L.
Published: July 2009

By using the quantum hydrodynamic and Maxwell equations, we derive the generalized nonlinear electron magnetohydrodynamic, the generalized nonlinear Hall-MHD (HMHD), and the generalized nonlinear dust HMHD equations in a self-gravitating dense magnetoplasma. Our nonlinear equations include the self-gravitating, the electromagnetic, the quantum statistical electron pressure, as well as the quantum electron tunneling and electron spin forces. They are useful for investigating a number of wave phenomena including linear and nonlinear electromagnetic waves, as well as three-dimensional electromagnetic wave turbulence spectra and structures arising from mode coupling processes at nanoscales in dense quantum magnetoplasmas.
Probing microwave capacitance of self-assembled quantum dots
Authors: Cheng Guanglei , Levy Jeremy , Medeiros-Ribeiro Gilberto
Published: July 2009

Self-assembled quantum dots have remarkable optical, electronic, and spintronic properties that make them leading candidates for quantum information technologies. Their characterization requires rapid and local determination of both charge and spin degrees of freedom. We present a way to probe the capacitance of small ensembles of quantum dots at microwave frequencies. The technique employs a capacitance sensor based on a microwave microstrip resonator with sensitivity ∼10−19 F/Hz, high enough to probe single electrons. The integration of this design in a scanning microscope will provide an important tool for investigating single charge and spin dynamics in self-assembled quantum dot systems.