bluuebunny/crossref_metadata_2025 huggingface dataset:
The topologies of separate continuity. I
Authors: Knight C. J. , Moran W. , Pym J. S.
Published: November 2008

A functionf( , ) of two variables is said to beseparately continuousif for each fixedyand each fixedx, the functionsf(,y) andf(x,) are continuous functions of one variable. Separately continuous functions seem to be playing a larger rôle in analysis than formerly. In (1) there is an account of the theory of semigroups in which the multiplication is separately continuous, and in (9) various analytic theorems are obtained by the study of separately continuous functionsf(s,t), wheretranges over a setT, andsranges over a set of functions onT.
Some results on hypoelliptic pseudo-differential operators
Authors: Elliott Robert J.
Published: November 2008

In this paper, by extending the results of Yoshikawa (8), we obtain local a priori inequalities for hypoelliptic pseudo-differential operators. Using these inequalities we then show how the results of Hormander ((3), Theorem 8·7·2), on the solvability of the adjoint operator of a principally normal operator can be extended to the adjoint operator of a hypoelliptic pseudo-differential operator. Finally, we consider a class of operators which satisfy more particular a priori inequalities and we show that these operators are hypoelliptic. This class of operators was studied by Egorov (1), and he shows them to be ‘of principal type’. They include elliptic operators and also the subelliptic operators of Hormander (4).
Non-Newtonian effects in axially symmetric oscillatory flows of some elastico-viscous liquids
Authors: Jones J. R.
Published: November 2008

In (general) elastico-viscous liquids the response to stress at any instant will depend on previous rheological history, the equations of state needed to describe the rheological properties of a typical material element at any instant t being expressible in the form of a (properly invariant†) set of integro-differential equations relating its deformation, stress and temperature histories (as defined by a metric tensor (of a convected frame of reference), a stress tensor and the temperature measured in the element as functions of previous time t'( < t)) together with the time lag (t – t') and physical constant tensors associated with the element (1). Thus in any type of oscillatory motion a rheological history will necessarily be a function of the frequency of the forcing agent, the rheological history of a number of different types of elastico-viscous liquids in some simple shearing oscillatory flows being a rather simple oscillatory history (see, for example, (2–4)). It is, therefore, to be expected that a liquid with elastic properties will behave somewhat differently from any inelastic viscous liquid when subjected to any kind of oscillatory motion, and it is for this reason that oscillatory motions have been used extensively to detect and measure the elastic properties of liquids (see, for example, (2–5)).
On a class of commutative Noetherian rings
Authors: Burch Lindsay
Published: November 2008

If A, B are ideals of a commutative ring R, such that B ⊆ A, and, for some positive integer r, Ar = BAr−1 then B is said to be a reduction of A. (This concept was defined and developed by Northcott and Rees in (1).) In this paper, I shall consider commutative Noetherian rings with the property that no non-zero principal ideal is a reduction of an ideal properly containing it.
On a theory of laminar flow in channels of a certain class
Authors: Fraenkel L. E.
Published: November 2008

This paper is concerned with the steady plane flow of a viscous fluid in symmetrical channels with slowly curving walls. The product of local channel half-width and local wall curvature is bounded by a small parameter ∈. We review the essentials of the formal approximation, in powers of ∈, proposed in (4) and (5); resolve a question, left open there, regarding the existence of the approximate series for the stream function for any value of the Reynolds number and to arbitrary order in ∈ and prove that, under certain restrictions on the Reynolds number and the divergence angle of the channel walls, this formal series is in fact a strict asymptotic expansion (for ∈ → 0) of an exact solution of the Navier–Stokes equations. As a result, the traditional picture of laminar separation, due to Prandtl, emerges as part of the steady flow field predicted by an exact solution that is known explicitly to arbitrary asymptotic order.
The Cousin complex and integral extensions of Noetherian domains
Authors: Sharp Rodney Y.
Published: November 2008

In this article, the word ‘ring’ will mean ‘commutative, Noetherian ring with non-zero multiplicative identity’, and it is to be understood that ring homomorphisms respect identity elements.
Binary forms and pencils of quadrics
Authors: Edge W. L.
Published: November 2008

The incitement, or provocation, to assemble the following pages was the recognition in a recent paper (5) of a geometrical property characterizing those pairs, in a pencil of quadric surfaces, such that the quadrics of a pair are both outpolar and inpolar to each other: symmetrically apolar let it be said. That there are three such pairs was known (8), but their identification by means of the principal chords of their common curve had apparently not been remarked upon. The question naturally arose as to the number and identification of such pairs of quadrics of a pencil in n-dimensional projective space [n]; it is easy to show that the number is ½n(n–1), but geometrical identification seems quite another matter and no success whatever has yet been achieved even when n is 4.
On the propagation of disturbances in a laminar boundary layer. II
Authors: Brown S. N. , Stewartson K.
Published: November 2008

The assumption that disturbances are confined to the neighbourhood of the wall in the problem of Part I is invalidated by an exact solution of the resulting equation which shows that disturbances rapidly travel out of the region in which the equation is applicable. The asymptotic methods of Part I are also applied to this equation, which was studied by Lam and Rott (1), and an assessment is made of the role of the eigensolutions found by these authors.
The use of Lagrangian coordinates in the water entry and related problems
Authors: Johnstone Eveline A. , Mackie A. G.
Published: November 2008

Lagrangian coordinates are used in conjunction with the self-similarity hypothesis in order to examine the problem of the vertical entry at constant speed of a wedge and also of a cone into an incompressible fluid initially at rest. Certain known properties of the free surface are recovered in a very direct and simple manner and new exact results concerning the inclination of the free surface and the angle of contact with the rigid surface are obtained.
The Spectrum of the Normal Frequencies of a Polar Linear Lattice
Authors: Broch E. K.
Published: November 2008

1. Introduction. The importance of the frequency spectrum of the lattice in problems concerning the properties of the crystalline state has often been emphasized. In particular, all the properties of a crystal which depend on the heat motion of the constituent particles require for their explanation a knowledge of the actual form of the vibrational spectrum.
The Dependence on Composition of the Critical Ordering Temperature in Alloys
Authors: Easthope C. E.
Published: November 2008

The statistical treatment of order-disorder transformations, as developed by Bethe and Peierls, has been extended to alloys having superlattices of the AB and AB3 types but compositions which differ slightly from the ideal compositions required for the formation of perfect superlattices. If the composition of the alloy is specified by the concentration c of one component, which we have chosen to be the A component, then the results show that for alloys of the AB type the critical temperature should have a maximum value when c = ½, that is, for the ideal composition. This is in agreement with experiment. For alloys of the AB3 type it is found that the maximum value should occur for some value of c > ¼. This result disagrees with that obtained experimentally, but both results agree, at least qualitatively, with those obtained by the theory of Bragg and Williams.
An A.C. Method of Measuring Resistance
Authors: Shoenberg D.
Published: November 2008

Some applications of an alternating field method to various problems of superconductivity are described. It is shown how the method can be used to measure the resistance and self inductance of a metal ring, and this was applied to show how the resistance of a superconducting tin ring is restored by a magnetic field. The method is also convenient for a rapid determination of the order of magnitude of the specific resistance of a substance, and to see whether or not it becomes superconducting; several elements were examined in this way, but no new superconductors were found.
Using types as search keys in function libraries
Authors: Rittri Mikael
Published: November 2008

A method is proposed to search for an identifier in a functional program library by using its Hindley–Milner type as a key. This can be seen as an approximation of using the specification as a key.

Functions that only differ in their argument order or currying are essentially the same, which is expressed by a congruence relation on types. During a library search, congruent types are identified. If a programmer is not satisfied with the type of a found value, he can use a conversion function (like curry), which must exist between congruent types, to convert the value into the type of his choice.

Types are congruent if they are isomorphic in all cartesian closed categories. To put it more simply, types are congruent if they are equal under an arithmetical interpretation, with cartesian product as multiplication and function space as exponentiation. This congruence relation is characterized by seven equational axioms. There is a simple term-rewriting algorithm to decide congruence, using which a search system has been implemented for the functional language Lazy ML, with good performance.

The congruence relation can also be used as a basis for other search strategies, e.g. searching for identifiers of a more general type, modulo congruence or allowing free type variables in queries.
A semantic basis for Quest
Authors: Cardelli Luca , Longo Giuseppe
Published: November 2008

Quest is a programming language based on impredicative type quantifiers and subtyping within a three-level structure of kinds, types and type operators, and values.

The semantics of Quest is rather challenging. In particular, difficulties arise when we try to model simultaneously features such as contravariant function spaces, record types, subtyping, recursive types and fixpoints.

In this paper we describe in detail the type inference rules for Quest, and give them meaning using a partial equivalence relation model of types. Subtyping is interpreted as in previous work by Bruce and Longo (1989), but the interpretation of some aspects – namely subsumption, power kinds, and record subtyping – is novel. The latter is based on a new encoding of record types.

We concentrate on modelling quantifiers and subtyping; recursion is the subject of current work.
A practical functional program for the CRAY X-MP
Authors: Boyle James M. , Harmer Terence J.
Published: November 2008

One can have all the advantages of functional programming – correctness, clarity, simplicity, and flexibility – without any sacrifice in performance, even for a scientifically significant computation on a supercomputer. Therefore, why use Fortran? We demonstrate parity – equality of speed and storage use – between a program generated automatically from a functional specification and a program written by hand in the procedural style. To our knowledge, this demonstration of parity is the first for a program that solves a scientifically significant problem – quasi-linear hyperbolic partial differential equations – on a scientifically interesting supercomputer – the CRAY X-MP. We use pure Lisp, including higher-order functions, to express the functional specification for the PDE solver. We designed this specification for maximal clarity and flexibility, rather than for efficiency. Nevertheless, we obtain a highly efficient program to solve the PDEs: automated program transformations put back the missing efficiency as they produce an executable Fortran program from the specification. The generated Fortran program vectorizes on the CRAY X-MP and runs about 4% faster than a handwritten Fortran program for the same problem. We describe the problem and the specification, and some of the problem-domain-specific and hardware-specific transformations that we use to obtain the high-efficiency program.
A run-time algorithm for managing the granularity of parallel functional programs
Authors: Aharoni Gad , Feitelson Dror G. , Barak Amnon
Published: November 2008

We present an on-line (run-time) algorithm that manages the granularity of parallel functional programs. The algorithm exploits useful parallelism when it exists, and ignores ineffective parallelism in programs that produce many small tasks. The idea is to balance the amount of local work with the cost of distributing the work. This is achieved by ensuring that for every parallel task spawned, an amount of work that equals the cost of the spawn is performed locally. We analyse several cases and compare the algorithm to the optimal execution. In most cases the algorithm competes well with the optimal algorithm, even though the optimal algorithm has information about the future evolution of the computation that is not available to the on-line algorithm. This is quite remarkable considering we have chosen extreme cases that have contradicting optimal executions. Moreover, we show that no other on-line algorithm can be consistently better than it. We also present experimental results that demonstrate the effectiveness of the algorithm.
The interactive Lazy ML system
Authors: Augustsson Lennart
Published: November 2008

In this paper we describe an implementation of an interactive version of the purely functional programming language Lazy ML (LML). The most remarkable fact about the interactive system is that it is written in a pure functional style using LML, yet the efficiency still compares favourably to other conventional interpretative systems.

We describe how the system is designed, and also the exception mechanism that was added to facilitate the handling of errors in the system.
Correctness of binding-time analysis
Authors: Palsberg Jens
Published: November 2008

A binding-time analysis is correct if it always produces consistent binding-time information. Consistency prevents partial evaluators from ‘going wrong’. A sufficient and decidable condition for consistency, called well-annotatedness, was first presented by Gomard and Jones. In this paper we prove that a weaker condition implies consistency. Our condition is decidable, subsumes the one of Gomard and Jones, and was first studied by Schwartzbach and the present author. Our result implies the correctness of the binding-time analysis of Mogensen, and it indicates the correctness of the core of the binding-time analyses of Bondorf and Consel. We also prove that all partial evaluators will on termination have eliminated all ‘eliminable’-marked parts of an input which satisfies our condition. This generalizes a result of Gomard. Our development is for the pure λ-calculus with explicit binding-time annotations.
A critique of Standard ML
Authors: Appel Andrew W.
Published: November 2008

Standard ML is an excellent language for many kinds of programming. It is safe, efficient, suitably abstract, and concise. There are many aspects of the language that work well.

However, nothing is perfect: Standard ML has a few shortcomings. In some cases there are obvious solutions, and in other cases further research is required.
A functional animation starter-kit
Authors: Arya Kavi
Published: November 2008

A functional approach presents a fresh perspective on the problem of animation. We present an implementation of a functional animation system written in Haskell, and illustrate how it may be used to create simple and colourful animations.
Worst case scheduling for parallel functional programs
Authors: Burton F. Warren , Rayward-Smith V. J.
Published: November 2008

Many of the details that a programmer must manage when programming in a procedural language are handled by the implementation in a functional language. In a parallel functional language, we would expect the assignment of processes to processors and the scheduling of processes to be handled by the implementation. The partitioning of a program into processes may be handled by the implementation as well.

We will assume that a parallel functional program may create processes dynamically, and that processes may synchronize in an arbitrary manner. It does not matter whether processes are defined in the source program or generated by the implementation.

On parallel systems where each processor has some local memory, it is common practice not to move processes once they have started to execute. We will show that if each process must be executed on a single processor, then no fully automatic scheduling strategy can ensure good performance.

We also will show that if all processes are sequential processes (i.e. do not contain internal parallelism), and if a process may be moved whenever it resumes execution following synchronization with another process, then good performance can be assured, at least in theory.
Funser: a functional server for textual information retrieval
Authors: Ziff Donald A , Spackman Stephen P , Waclena Keith
Published: November 2008

This paper describes a data-intensive application written in a lazy functional language: a server for textual information retrieval. The design illustrates the importance of interoperability, the capability of interacting with code written in other programming languages. Lazy functional programming is shown to be a powerful and elegant means of accomplishing several desirable concrete goals: delivering initial results promptly, using space economically, and avoiding unnecessary I/O. Performance results, however, are mixed.
Implementing a functional spreadsheet in clean
Authors: De Hoon Walter A. C. A. J , Rutten Luc M. W. J , van Eekelen Marko C. J. D
Published: November 2008

It has been claimed that recent developments in the research on the efficiency of code generation and on graphical input/output interfacing have made it possible to use a functional language to write efficient programs that can compete with industrial applications written in a traditional imperative language. As one of the early steps in verifying this claim, this paper describes a first attempt to implement a spreadsheet in a lazy, purely functional language. An interesting aspect of the design is that the language with which the user specifies the relations between the cells of the spreadsheet is itself a lazy, purely functional and higher order language as well, and not some special dedicated spreadsheet language. Another interesting aspect of the design is that the spreadsheet incorporates symbolic reduction and normalisation of symbolic expressions (including equations). This introduces the possibility of asking the system to prove equality of symbolic cell expressions: a property which can greatly enhance the reliability of a particular user-defined spreadsheet. The resulting application is by no means a fully mature product. It is not intended as a competitor to commercially available spreadsheets. However, with its higher order lazy functional language and its symbolic capabilities it may serve as an interesting candidate to fill the gap between calculators with purely functional expressions and full-featured spreadsheets with dedicated non-functional spreadsheet languages. This paper describes the global design and important implementation issues in the development of the application. The experience gained and lessons learnt during this project are discussed. Performance and use of the resulting application are compared with related work.
A polymorphic library for constructive solid geometry
Authors: Davy J. R. , Dew P. M.
Published: November 2008

Solid modelling using constructive solid geometry (CSG) includes many examples of stylised divide-and-conquer algorithms. We identify the sources of these recurrent patterns and describe a Geometric Evaluation Library (GEL) which captures them as higher-order functions. This library then becomes the basis of developing CSG applications quickly and concisely. GEL is currently implemented as a set of separately compiled modules in the pure functional language Hope+. We evaluate our work in terms of performance and general applicability. We also assess the benefits of the functional paradigm in this domain and the merits of programming with a set of higher-order functions.
Proof-irrelevance out of excluded-middle and choice in the calculus of constructions
Authors: Barbanera Franco , Berardi Stefano
Published: November 2008

We present a short and direct syntactic proof of the fact that adding the axiom of choice and the principle of excluded-middle to Coquand–Huet's Calculus of Constructions gives proof-irrelevance.
The bologna optimal higher-order machine
Authors: Asperti Andrea , Giovannetti Cecilia , Naletto Andrea
Published: November 2008

The Bologna Optimal Higher-order Machine (BOHM) is a prototype implementation of the core of a functional language based on (a variant of) Lamping's optimal graph reduction technique (Lamping, 1990; Gonthier et al., 1992a; Asperti, 1994). The source language is a sugared λ-calculus enriched with booleans, integers, lists and basic operations on these data types (following the guidelines of Interaction Systems – Asperti and Laneve (1993b, 1994), Laneve (1993)). In this paper, we shall describe BOHM's general architecture (comprising the garbage collector), and give a large set of benchmarks and experimental results.
Formalization and computational aspects of image analysis
Authors: Alvarez Luis , Morel Jean Michel
Published: November 2008

In this article we shall present a unified and axiomatized view of several theories and algorithms of image multiscale analysis (and low level vision) which have been developed in the past twenty years. We shall show that under reasonable invariance and assumptions, all image (and shape) analyses can be reduced to a single partial differential equation. In the same way, movie analysis leads to a single parabolic differential equation. We discuss some applications to image segmentation and movie restoration. The experiments show how accurate and invariant the numerical schemes must be and we compare several (old and new) algorithms by discussing how well they match the axiomatic invariance requirements.
Ultraschalldiagnose der Echinokokken-Cholangitis
Authors: Badea R. , Badea Gh. , Drağhici A. , Cazacu M. , Porr P. J.
Published: November 2008

Anhand eines klinischen Falles wird die Rolle der Sonographieuntersuchung bei Echinokokken-Cholangitis unterstrichen. Durch Perforation der zystischen Echinokokkose der Leber in die Gallenwege entsteht das klinische Bild einer akuten Cholangitis, die schwer von dem einer Choledocholithiasis abzugrenzen ist. Durch Sonographieuntersuchung wurde die richtige Diagnose gestellt und intraoperativ bestätigt. Es wird auf die Bedeutung der Notfall-Sonographieuntersuchung bei Schwerkranken hingewiesen.
Die „Reifung“ des Darmes während der Schwangerschaft; fortlaufende Beobachtung mit Ultraschall
Authors: Bonilla-Musoles F. , Perez Gil M. , Ramirez J. V. , Pelliger A. , Ferrez-Barriendos J. , Sanchez-Peña J. M.
Published: November 2008

Die echographischen Bilder des Darmes während der letzten 20 Schwangerschaftswochen werden beschrieben. Vergleiche mit dem biparietalen und abdominalen Durchmesser sowie mit dem echographischen Bild der Plazenta werden durchgeführt.

Die “Reifung” des Darmes wird in 4 Stufen unterteilt; die beiden letzten Stufen sind nur bei reifen Feter vorhanden.
Development of and Clinical Experience with a New TV Monitoring System in Electronic Endoscopy
Authors: Okano H. , Kodama T. , Takino T.
Published: November 2008

We developed a bi-plane TV monitoring system using a TV endoscope (Electronic endoscope manufactured by Toshiba-Machida, Tokyo, Japan) that permits simultaneous display of real-time and prerecorded images. Various findings of the two examinations can be precisely compared using this system, and a detailed evaluation of the progress of peptic ulcers obtained. In addition, the effects of various endoscopic therapies can be accurately evaluated. In endoscopic injection sclerotherapy of esophageal varices, now varices (or recurrent varices) were differentiated. In laser therapy for early gastric cancer, precise delimitation of the lesion for radiation was possible, and the therapeutic effects were more accurately evaluated. These results show the diagnostic as well as therapeutic usefulness of this system. Furthermore, for the examination of the lower digestive tract, X-ray images were incorporated into this system. This is a useful modality for diagnostic and therapeutic procedures in colonic disease.
High-Resolution-CT bei interstitiellen Lungenerkrankungen
Authors: Kullnig P.
Published: November 2008

Das Erscheinungsbild im High-Resolution-CT (HR-CT) des Thorax von 39 Patienten mit histologisch gesicherten interstitiellen Lungenerkrankungen wurde untersucht (22 fibrosierende Alveolitis, 12 Lymphangitis carcinomatosa, 5 Lymphangioleiomyomatose (LAM)). Das markanteste Merkmal in der Gruppe der Patienten mit fibrosierender Alveolitis waren Honigwabenzysten in vornehmlich subpleuraler Distribution und mit Destruktion der zugrundeliegenden Lungenarchitektur. Bei LAM fanden sich zystische Strukturen ohne Distraktion des Lungengerüstes und ohne prädominante Lokalisation. Die Patienten mit Lymphangitis carcinomatosa zeigten septale und polygonale Strukturen mit unregelmäßiger Dicke sowie noduläre Läsionen entlang der bronchovaskulären Leitstrukturen. Die HR-CT erlaubt eine exzellente Korrelation mit der zugrundeliegenden Pathologie. Des weiteren konnten mittels der HR-CT Merkmale identifiziert werden, welche eine Differenzierung der Krankheitsgruppen untereinander erlaubten.
Getrennte Messung von Kompakta- und Spongiosadichte mit einem Transversal-Rotations-Scanner
Authors: Schneider P. , Berger P. , Moll E. , Reiners Chr. , Börner W.
Published: November 2008

Mit einem hochauflösenden mikrocomputergesteuerten Transversal-Rotations-Scanner, der eine eng kollimierte 125J-Photonenquelle und einen Szintillationsdetektor bewegt, werden die von der Knochenmineralisation abhängigen Absorptionsprofile am distalen Unterarm gemessen. In zwei Schritten erfolgt zunächst die Rekonstruktion der anatomischen Struktur an der Meßstelle. Dann werden über einen Least-Square-Algorithmus die drei linearen Schwächungskoeffizienten für Weichteile, Kompakta und Spongiosa ermittelt. Die Schwächungskoeffizienten der Kompakta und Spongiosa dienen als Maß für die Mineralisation des Knochens. Die Übereinstimmung zwischen rekonstruiertem Bild mit den daraus berechneten Ergebnissen und den Meßwerten kann durch eine spezielle Fehlerrechnung geprüft werden. Am physikalischen Modell bzw. bei In-vivo-Messungen ergibt sich für 10fach-Messungen ein Variationskoeffizient von 1,8 bzw. 3,3 % für die Kompakta und von 2,5 bzw. 3,8 % für die Spongiosa. Die relative Abweichung vom Sollwert als Maß für die Richtigkeit liegt - in Abhängigkeit von der Dichte - zwischen +1,3 und -1,0 %. Das vorgestellte neue, technisch wenig aufwendige Verfahren zur getrennten Bestimmung der Dichte von Kompakta und Spongiosa am distalen Radius soll zur Früherfassung von Änderungen der Knochenmineralisation dienen, die sich im allgemeinen zuerst in der Spongiosa abspielen.
Constitutive modeling of Hugoniot for a highly porous material
Authors: Resnyansky A. D.
Published: November 2008

This paper studies the constitutive behavior of highly porous materials subject to shock wave loading. A two-phase model accounting for the interphase heat transfer is suggested and employed. Experimental shock velocity data, widely available in literature, are used for the purpose of model validation. The importance of the nonequilibrium Hugoniot analysis is demonstrated. It is argued that the apparent anomalous behavior of the experimental Hugoniots for a highly porous material is closely associated with the thermal interphase nonequilibrium. In particular, an experimental copper powder Hugoniot correlates with a composite curve constructed from a fragment of the pressure-temperature equilibrium Hugoniot at pressures below 40 GPa and from a fragment of the pressure equilibrium Hugoniot at higher pressures.
Hysteresis in In2O3:Zn nanowire field-effect transistor and its application as a nonvolatile memory device
Authors: Zhang Wenfeng , Jie Jiansheng , Luo Linbao , Yuan Guodong , He Zhubing , Yao Zhiqiang , Chen Zhenhua , Lee Chun-Sing , Zhang Wenjun , Lee Shuit-Tong
Published: November 2008

Control and utilization of hysteresis in nanodevices is an important issue. In this paper, we show an enormous hysteresis in zinc-doped In2O3 nanowire field-effect transistors. Various measurements including changing the operating atmosphere, ozone treatment, and surface passivation were performed to understand and control the hysteresis. The hysteresis could be readily controlled by modifying the nanowire surface. Utilizing the hysteresis, the as-fabricated devices can function as nonvolatile memory elements with high charge storage stability exceeding 4 h. We propose that chemical species such as water molecules adsorbed on the devices and surface oxygen defects in the amorphous layer mainly originated from Zn2+ substitution of In3+ are the main causes of the large hysteresis and the nonvolatile memory effect.
Resolving the characteristics of morphotropic phase boundary in the (1−x)Pb(Fe1/2Nb1/2)O3–xPbTiO3 system: A combined dielectric and synchrotron x-ray diffraction study
Authors: Singh Satendra Pal , Pandey Dhananjai , Yoon Songhak , Baik Sunggi , Shin Namsoo
Published: November 2008

Frequency dependent dielectric studies on the mixed system (1−x)Pb(Fe1/2Nb1/2)O3–xPbTiO3 reveal contributions from the electrodes, grain boundaries, and grains. It is shown that the intrinsic value of the dielectric permittivity coming only from the grains peaks at x=0.08. Analysis of synchrotron x-ray diffraction profiles using the Rietveld technique shows that this peaking is linked with a monoclinic to tetragonal morphotropic phase transition in the multiferroic system.
Understanding eigenfrequency shifts observed in vortex gyrotropic motions in a magnetic nanodot driven by spin-polarized out-of-plane dc current
Authors: Choi Youn-Seok , Kim Sang-Koog , Lee Ki-Suk , Yu Young-Sang
Published: November 2008

We observed sizable eigenfrequency shifts in spin-polarized dc-current-driven vortex gyrotropic motions in a soft magnetic nanodot, and clarified the underlying physics through micromagnetic numerical calculations. It was found that the vortex eigenfrequency is changed to higher (lower) values with increasing Oersted field (OH) strength associated with the out-of-plane dc current for the vortex chirality parallel (antiparallel) to the rotation sense of the OH circumferential in-plane orientation. The eigenfrequency shift was found to be linearly proportional to the current density j0 in the linear regime as in ΔνD≃±ηj0/|G|, where G is the gyrovector constant and η is a positive constant, e.g., 1.9×10−8 erg/A for a model Permalloy dot of 300 nm diameter and 20 nm thickness. This behavior originates from the sizable contribution of the OH to the effective potential energy of a displaced vortex core in the gyrotropic motion. The present results reveal that νD, an intrinsic dynamic characteristic of a given nanodot vortex state, is controllable by changes in both the density and direction of spin-polarized out-of-plane dc currents.
Permittivity enhancement of hafnium dioxide high-κ films by cerium doping
Authors: Chalker P. R. , Werner M. , Romani S. , Potter R. J. , Black K. , Aspinall H. C. , Jones A. C. , Zhao C. Z. , Taylor S. , Heys P. N.
Published: November 2008

The effect of cerium doping on the dielectric properties of hafnium dioxide is reported. Thin films of cerium-doped hafnium oxide Cex–Hf1−xO2 (x=0.10,0.17,0.34) have been grown by liquid injection atomic layer deposition. After annealing at 900 °C, all films were transformed from an amorphous state into a stabilized cubic or tetragonal phase. As-deposited films of Ce0.1–Hf0.9O2 showed low hysteresis voltages and negligible flat band voltage shifts. After annealing to form the crystalline cubic or tetragonal phase, the relative permittivity (κ) increased from 25 to 32 at 100 kHz with leakage current densities at ±1 MV cm−1 of ∼1.58×10−5 A cm−2.
Use of statistical process control for coastal marine biological impact analysis
Authors: Maurer D. , Robertson G. , Mengel M. , Gerlinger T. , Lissner A.
Published: November 2008

Statistical process control, a procedure long practiced in industry, was assessed to determine its applicability as an ecological analysis technique. The procedure is easy to calculate, emphasizes visual display of data, facilitates analysis and comparison, and uses well tested zone rules to objectively identify out-of-control conditions. Statistical process control was applied to a marine database involving number of species, abundance and biomass of benthic invertebrates sampled over 13 years (July 1985 to April 1998). Two stations were evaluated representing reference and impact (i.e. test) conditions.

Statistical process control revealed that some out-of-control conditions were naturally induced whereas others were probably related to anthropogenic activities. The procedure also effectively depicted seasonal fluctuations and long-term trends. Patterns and major trends identified using the technique corroborated those previously documented by analyses using more conventional approaches. While the procedure is well established as an industrial quality control protocol, it has the flexibility and latitude to be considered as a useful tool in evaluating biological impacts. Comments on management applications are included.
Organochlorine pesticides and polychlorinated biphenyls in the environment of the Baikal region
Authors: Politov S.V. , Anokhin Yu.A. , Surnina N.N.
Published: November 2008

The pollution level of some organochlorine pesticides and polychlorinated biphenyls in snow and surface waters of all main altitudinal belts of the mountains surrounding Lake Baikal was estimated for the first time.

The southern part of the Baikal region was more polluted by hexachlorocyclohexanes (consisting of the pesticide lindane and the isomer α-hexachlorocyclohexane and polychlorinated biphenyls) than the northern part, pointing out the role of atmospheric pollution sources, located mainly to the west of Lake Baikal. Dichlorodiphenyltrichloroethane (sum of the isomers) contents in snow did not show spatial differences and varied little with altitude. In the Baikal region this pesticide is apparently mainly of global origin.

The organochlorine contamination of surface waters of the Lake Baikal catchment area showed great spatial and temporal variations. Organochlorine pesticides were observed in the main tributaries of Lake Baikal throughout the year.

Dichlorodiphenyltrichloroethane balance showed that this substance in soil exceeds by dozens of times its atmospheric deposition, which proves the great resistance of the pesticide to breakdown in the Baikal environment and indicates the large volume of its deposition in previous years.
Ecotoxicological studies of the impact of construction materials for shore protection on Lake Baikal
Authors: Kudelin V.M.
Published: November 2008

Shore slopes of the majority of reservoirs are subjected to wave abrasion. Mainly ferro-concrete structures for shore protection against destruction were built on Lake Baikal. A plan to use new structures, such as wave extinguishing berms and artificial beaches of non-sorting rock material, is in effect at present. For the practical evaluation of this plan, it was necessary to perform an ecotoxicological assessment.

The investigations started in 1988 and were carried out annually. At the first stage of the investigations, toxic potential of construction material was examined. Model experiments conducted on various biota did not reveal any toxicity.

In the second stage, in the region of soil embankment, the influence of the construction material on hydrochemical composition of coastal waters and on ichthyofauna was studied. The analyses of water samples revealed that there was no negative influence of embankment on chemical composition of water of the littoral zone. The berm construction did not cause any changes in fish community composition. The construction did not influence the number of benthic littoral sculpins (Family Cottidae) or the reproduction of littoral spawning fish.

The data reveal no negative influence of the soil embankment on shallow littoral areas.
Preliminary results about contaminants in the biota of Lake Baikal
Authors: Beim A. , Grocheva E. , Renzoni A.
Published: November 2008

Recent analyses of the muscle of several fish specimens and the muscle, liver and fat of the Baikal seal show low levels of heavy metals and organochlorine compounds.

Present and past observations suggest that despite land-based sources of pollution, the general health status of the lake is good. However, because of increasing local air pollution, the long-range transport of pollutants emitted elsewhere and the expected increase in pollutants reaching the lake via rivers, extremely careful control measures in the hydrographic basin and continuous monitoring of the lake water are essential.
Ecotoxicological assessment in the rivers Rhine (The Netherlands) and Po (Italy)
Authors: Camusso M. , Vignati D. , van de Guchte C.
Published: November 2008

This paper compares several aspects of water and sediment pollution in the Rhine and Po rivers. The data were selected from previously published material following criteria that considered natural differences between the two river basins and also differences in the experimental approaches employed. One aim of the comparison was to highlight differences in approach between the Italian and Dutch water authorities and to assess the advantages of standardising methodologies for water quality assessment between Italy, The Netherlands, and other member countries of the European Union.

Water quality in the Po and the Rhine was found to be similar; levels of trace metals, with the exception of copper, were below current environmentally acceptable targets, and the toxicity of water extracts to water fleas were closely similar. The main problem in both basins was diffuse inputs of nutrients and biocides from agriculture.

By contrast, there were considerable differences between the rivers in terms of sediment contamination, which was much worse in the Rhine. Potentially dangerous levels of organochlorides were found in sediments from both rivers, yet concentrations were much higher in Rhine sediments, particularly in the deltaic area, which contained very high levels of certain trace metals and polyaromatic hydrocarbons.

It is concluded that the two rivers share many environmental quality problems, and that harmonisation of experimental and monitoring procedures between the two rivers would not only assist research but promote more efficient management policies.
Influence of sediment organic matter and fluoranthene-spiked sediments on some bacterial parameters in laboratory freshwater/formulated sediment microcosms
Authors: Verrhiest G. , Clément B. , Merlin G.
Published: November 2008

Aquatic microcosm tests are widely used to assess the toxic effects of chemical contaminants on higher pelagic and benthic organisms, but rarely take into account bacteria and other microorganisms. In this study, the bacterial compartment of freshwater/formulated sediment laboratory microcosms was monitored in 4-week tests. In a first experiment, the influence of various organic matter compositions (cellulose + TetraMin®, cellulose + spirulin + meat extract, peat moss + TetraMin®) on bacterial communities was studied. In a second experiment, the effect of fluoranthene on bacterial communities was estimated. The following bacterial parameters were measured: total bacteria counts (epifluorescence microscopy) and enzymatic activities (INT-reductase and β-glucosidase). Compared to natural sediments, the artificial sediment was a satisfactory support for bacterial development. The organic composition of the formulated sediments had no apparent influence on bacterial populations. This result could be due to the high variability of parameters, such as the using 2-p-iodophenyl-3-p-nitrophenyl-5-phenyltetrazolium chloride-reductase activity, and to the C/N ratio similarity between the tested organic matters. The fluoranthene-contaminated sediment had no apparent effect on bacterial populations. The absence of toxicity could be due in part to the uncontaminated surficial sand layer of the sediment which might have protected pelagic organisms by limiting the rate of suspended contaminated particles and creating an uncontaminated refuge for benthic organisms.
Sediment mutagenicity testing: development of substance specific bacterial strains for the detection of mutagenic aromatic nitrogen compounds and oxidative mutagens
Authors: Vahl H.H. , Karbe L. , Prieto-Alamo M.J. , Pueyo C. , Westendorf J.
Published: November 2008

The arabinose resistance forward mutation assay was chosen for the development of bacterial strains in order to get specific mutagenic responses. Special strains of Salmonella typhimurium were constructed which show an elevated expression of nitroreductase and O-acetyltransferase. They were shown to be highly sensitive to mutagenic nitro-compounds (e.g. 1-nitropyrene and 1,8-dinitropyrene) and, after metabolic activation by rat liver S9-mix, also to mutagenic amino-compounds (2-aminoanthracene). Furthermore, strains of Escherichia coli with reduced expression of antioxidative enzymes (catalase and superoxide dismutase) were constructed. However, they were only moderately sensitive to oxidative mutagens such as quinones, nitrogen compounds, and the herbicide paraquat, because, in contrast to the Salmonella strains used, they build up a complete gram-negative cell wall. For this reason, the Escherichia strains were further genetically altered in order to make their cell wall penetrable to lipophilic compounds. This alteration increased the sensitivity to more lipophilic compounds. The strains were more sensitive to 1-nitropyrene by a factor of more than 10 and to 1,8-dinitropyrene by a factor of more than 100.

In order to validate the arabinose resistance test with the newly constructed strains, sediments of the whole German part of the Elbe River were examined. Overall mutagenicity (standard strains) as well as enhanced effects with the special strains were observed in sediment samples of the river. Mutagenic hot spots reflect direct industrial influences as well as hydrologic situations, which has led to concentration of the organic content of suspended matter, loaded with industrial or rural contamination. Generally, high mutagenic effects were observed where chemical analyses showed a high degree of contamination.
An integrated approach to assess the benthic quality after sediment capping in Venice lagoon
Authors: Bona F. , Cecconi G. , Maffiotti A.
Published: November 2008

The present study was conducted in the Lago dei Teneri area of the Venice Lagoon in Italy. This area has long received massive pollutant input from the industrial area of Porto Marghera. It is adjacent to the Canale dei Petroli, an important industrial waterway. Because of its location, this area represents an ideal site for applying a new remedial solution: the capping of contaminated sediment with clean sand to support the benthic recolonization of the sediment. Capping was selected for this anoxic and most contaminated portion of the area as the most cost-effective way to provide a clean benthic habitat, to isolate the contamination and prevent contaminate release. An extensive sediment monitoring program was in place before, during and after the capping operations. Monitoring activities included hydrodynamics, measurement of cap thickness, in situ sediment profile imaging, benthos colonization, analysis of contaminants, and toxicity tests with Microtox and amphipods. To evaluate the efficiency of the capping, the results were analyzed with an integrated approach, which includes the Habitat Evaluation System. This approach allowed the quantification of the environmental benefits with respect to remediation of the Venice lagoon.
SEDS: setting environmental decisions for sediment, a decision making tool for sediment management
Authors: Krantzberg G. , Reynoldson T. , Jaagumagi R. , Bedard D. , Painter S. , Boyd D. , Pawson T.
Published: November 2008

The need for guidance on the management of contaminated sediment has been articulated by the International Joint Commission, scientists and resource managers in many jurisdictions. There is a growing convergence on what constitutes a valid comprehensive sediment assessment but active debate on how to synthesize multiple pieces of information on sediment chemistry, biological information from field monitoring and laboratory sediment bioassessment.

Recognizing the current state of knowledge, we provide a recommended approach to bioassessment sediment management strategies. The intent is to facilitate the formulation of data interpretation tools needed for a decision making process that is flexible to enable site-specific determination regarding the need to take action beyond the control of sources of contamination.

While the concepts contained herein have been employed implicitly in Canada and Ontario, the details on data collection, evaluation, and reaching a management decision are explicitly laid out in this paper. It is expected that field application of this approach could lead to modifications of this framework.
An unusual 4-methyl sterol present in abyssal sediments from the north-east Atlantic Ocean
Authors: Santos V.L.C.S. , Billett D.S.M. , Wolff G.A.
Published: November 2008

Four undisturbed sediment cores were collected from the Porcupine Abyssal Plain, an area in the north-east Atlantic ocean (48°N,16°W) characterised by seasonal surface phytoplankton blooms which lead to the pulsed input of organic matter to the benthos of which holothurians are considered to be the dominant biomass. In order to investigate the geochemistry of sedimentary organic matter in the deep ocean, these sediments were analysed for sterols by gas chromatography and mass spectrophotometry. Ten sterols were detected in the surficial sediments (Z-cholesta-5,22-dien-3β-ol, E-cholesta-5,22-dien-3β-ol, cholest-5-en-3β-ol, 5α(H)-cholestan-3β-ol, 24-methylcholesta-5,22-dien-3β-ol, 4α-methyl-5α(H)-cholestan-3β-ol, 24-ethylcholesta-5,22-dien-3β-ol, 24-ethylcholest-5-en-3β-ol, 5α(H)-24-ethyl-cholestan-3β-ol, 4α,23,24-trimethyl-5α-cholest-22-en-3β-ol) which decreased rapidly in concentration with increasing sediment depth. The prominent sterol of almost all surficial samples was 4α-methyl-5α-(H)-cholestan-3β-ol, the predominant sterol in two out of four samples. The exact reason for the abundance of this unusual compound in marine sediments is still not clear. However, two possible explanations for its high concentration are: (i) a contribution from one or several species of dinoflagellate (or possibly other algae) that were present in the phytoplankton bloom, which occurred in surface waters some two months prior to sampling; and (ii) a contribution to the sediment by benthic invertebrates (from faecal material), specifically holothurians. The total sterol concentration rapidly decreased with depth in the sediments and in the deeper sections of all of the cores, only cholest-5-en-3β-ol and 24-ethyl-cholest-5-en-3β-ol were detected.