bluuebunny/crossref_metadata_2025 huggingface dataset:
A new solution for the acoustic pressure‐field in a perfect wedge
Authors: Borejko Piotr
Published: June 2004

A time domain analytical solution is presented for the acoustic pressure‐field due to an impulsive point source in a liquid wedge with a rigid sloping bottom. The horizontal boundary of the wedge is a pressure‐release surface. The wedge is isovelocity, and it is three‐dimensional (3‐D) in that the source and the receiver are not restricted to the plane perpendicular to the wedge apex. This 3‐D wedge with perfectly reflecting (i.e., impenetrable) boundaries, the 3‐D perfect wedge, is the simplest theoretical model of a shallow water environment in which the ocean bottom has a constant slope, but it is inadequate in that it cannot account for acoustic penetration of the bottom typical for a real ocean floor.

In a perfect wedge, the acoustic field produced by a point source consists of two components: the diffraction field due to scattering at the apex, which under certain conditions vanishes [1], and the image field including the wave emitted by the source and a number of waves reflected off the wedge boundaries. These waves with spherical wave fronts propagate along the stationary time paths (the ray paths). The repeated reflections from the sloping bottom introduce the curvature into the projection of the ray path onto the horizontal boundary, provided that the first segment of this path originating at the source has a cross‐slope component. This path curvature in the horizontal is known as “horizontal, or bathymetric refraction” [2]. The ray path that leaves the source propagating up‐slope may be turned around to reach the receiver propagating back down‐slope. This change in propagation direction, known as “backscattering” [2], is due to multiple bottom reflections. The receiver can thus be reached along one of the two ray paths: the direct path or the indirect path which is turned around on approaching the apex. The image field in the wedge is thus three‐dimensional, i.e., it depends on three spatial coordinates: the range (normal to the apex), the cross‐range (parallel to the apex), and the depth coordinate.
Sound Insulation by Laminated Viscoelastic Plates
Authors: Langer S. , Schanz M. , Antes H.
Published: June 2004

Plates are basic components in industrial structural design whose acoustical properties are often very important to reduce noise, e.g., in a car or a building. The sound insulation by plates is influenced by various effects, e.g., by the plate's mass but also by their damping capability. Hence, for a realistic analysis, damping should be taken into account which can approximatively be modelled by the use of a viscoelastic material law.

Moreover, in automotive industry and structural engineering, laminated plates are very common to improve stiffness and stability, where plates with a viscoelastic core and rigid faces show additionally an excellent acoustical behaviour. Those laminated panes with a viscoelastic core are used in the design of windscreens, and, to improve sound insulation, in the design of building windows.

Here, the mechanical behaviour of such a laminated plate is described by using a homogenisation procedure. The damping property of the plate is influenced by the stiffness of the viscoelastic core, it's dissipation factor, and by the thickness of the dissipating layer. These properties of a three‐layer‐plate are mapped on homogenised material parameters of a simple plate via the Ansatz of Ross, Kerwin and Ungar (RKU‐Ansatz).

Finally, the sound insulation effectiveness of plates is analysed numerically.
Influence of Incompressibility on Different Wave Types in Porous Media
Authors: Pryl Dobromil , Schanz Martin
Published: June 2004

There are three wave types in poroelastic continua, the fast compressional wave, with solid and fluid moving inphase, the shear wave, and the second (slow) compressional wave, which has no equivalent in elastic materials, with solid and fluid moving in opposite directions. The fast compressional wave propagates with infinite speed if both constituents are modelled incompressible.

Numerical results of BEM calculations showing the influence of incompressible constituents will be presented as well as elements employing different shape functions for the solid displacements and the pore pressure.
Capillary and Gravity Waves on Bounded Region of Flow Free Surface
Authors: Sherykhalina Nataliya , Zhitnikov Vladimir
Published: June 2004

The problems of two‐dimensional flow of inviscid incompressible fluid are considered. The flow is bounded on one side with rectilinear wall possessing a gap. The fluid is assumed to be weightless in the first problem and surface tension is taken into account. The fluid is to be gravity in the second problem. The problems are solved at linear and nonlinear statement.
Stieltjes Truncated Moment Problem with Point Constraints
Authors: Adamyan Vadim M. , Tkachenko Igor M.
Published: June 2004

The truncated Hamburger and Stieltjes moment problems [1] were solved elsewhere (see [3] and references therein) using the methods of the extension theory of Hermitian operators and, in particular, the results on extensions of nonnegative operators and matrices. Moreover, applying methods of the extension theory we found a purely algebraic algorithm for the solution of both problems. Here we solve the corresponding moment problems with point constraints.
On the representation of generalized axially symmetric potentials in the neighbourhood of an isolated singularity
Authors: Berglez Peter
Published: June 2004

We give explicit representations of generalized axially symmetric potentials using certain differential operators acting on holomorphic functions. This is done for potentials defined in simply connected domains as well as defined in the neighbourhood of an isolated singularity. Further the kernel of an integral operator ‐ the so called Riemann matrix function ‐ is given in an explicit form for an integral representation of the potentials.
Anisotropic Wavelet Bases and Restricted Nonlinear Approximation
Authors: Hochmuth Reinhard
Published: June 2004

Restricted nonlinear approximation is a generalization of n‐term approximation in which a weight function is used to control the terms of the approximant. Here, restricted nonlinear approximation is considered with respect to anisotropic wavelet bases. In particular, characterizations for those functions, which provide a specific convergence rate by restricted nonlinear approximation, are presented.
Thermal control of Huygens mock up probe in Earth atmosphere: Thermo‐fluid dynamic simulation and mission data
Authors: Bettanini Carlo , Antonello Marco , Bianchini Giannandrea
Published: June 2004

A mock up of Huygens probe with 76 channels acquisition has been developed at University of Padova and successfully flown with a stratospheric space balloon from Italian Space Agency Base in Trapani on May 30th 2002. Temperature sensors have monitored temperature profiles in critical points of electronics, batteries and structure during raise at 40 km altitude, floating and parachuted descent. A thermal model of the probe has been implemented taking into consideration incoming external fluxes (solar direct, albedo and radiative heat fluxes), internal heat fluxes generation and convective heat transfer with atmosphere as a function of probe altitude. For the evaluation of convective fluxes and probe spinning rates an algebraic turbulent model, developed by the present authors, has been employed. This model is suitable to predict effects such as flow curvature and separation and solid boundary rotations. Simulation results have been utilized during project phase to optimize thermal paths in order to keep critical components in the allowable temperature range and for post flight analysis of mission data. These data show that passive thermal control of the probe has performed as expected contributing to a extremely successful scientific flight.
On the boundary value problem of water infiltration into a nonhomogeneous unsaturated soil
Authors: Marinoschi Gabriela , Morega Alexandru
Published: June 2004

The paper deals with the resolution of an optimization problem related to the nonlinear water infiltration into a stratified soil with two layers, for the hydraulic model introduced by Broadbridge and White.
On the mathematical modelling of dynamic problems in a micro‐periodic composite material
Authors: Rychlewska Jowita , Wozniak Czeslaw
Published: June 2004

The aim of this paper is to propose a certain new approach to the formulation of both discrete and continuum models for the analysis of dynamic problems in elastic composite solids with a periodic microstructure. The proposed approach is based on a periodic simplicial division of the unit cell and on the assumption of a uniform strain in every simplex. The main feature of the obtained discrete model is the finite‐difference form of governing equations. By applying smoothing operation the continuum models are derived directly from the discrete ones.
Traveling waves for chemotaxis–systems
Authors: Schwetlick Hartmut
Published: June 2004

In this paper we study the existence of traveling wave solutions to the Keller‐Segel model, a general model of chemotaxis, where the species do not reproduce. In the case of logarithmic sensitivity we show that various functionals modeling the reactive feedback on the chemo‐attractant do allow for traveling waves and a wide range of qualitatively different behavior is possible. We can find monotone fronts as well as pulse solutions in the densities of the population and the chemical. In particular, a new kind of solution exists, where both densities travel as pulses.
A constructive approach to modelling the tight shapes of some linked structures
Authors: Starostin E.L.
Published: June 2004

A variational approach is used to find the shortest curves confined to lie in two orthogonal planes and separated by a constant distance. The method is applicable to constructing tight shapes of linked structures each component of which is known to be planar. The shapes of the Borromean rings and two clasped pieces of rope are two examples. A concept of tight periodic structures is introduced and discussed.
Vibration of the soil caused by a vehicle moving over the randomly uneven surface of a slab track
Authors: Grundmann H. , Lenz S.
Published: June 2004

A vehicle which passes an uneven surface of a slab track causes vibrations of the whole system: the vehicle, the slab track and the subsoil. For a given random unevenness Δw of the slab track surface, covariances of the soil surface motion are calculated.
Sparse Quadrature as an Alternative to Monte Carlo for Stochastic Finite Element Techniques
Authors: Keese A. , Matthies H. G.
Published: June 2004

We consider the solution of nonlinear stochastic partial differential equations by a Galerkin‐method and by projection in the stochastic dimension and compute the occurring high‐dimensional integrals by sparse (Smolyak)‐ and Monte Carlo‐integration.
On the application of a combined heuristic technique in structural reliability analysis
Authors: Rottschäfer J. , Schmidt H. , Thierauf G.
Published: June 2004

In approximate reliability analysis usually an optimization problem has to be solved. In this contribution a combined heuristic algorithm is described which is well‐suited for problems, for which the application‐requirements of gradientbased algorithms are not fulfilled.
Reliability of a Rail with Respect to the Shakedown
Authors: Sieniawska R. , Wysocka A. , Żukowski S.
Published: June 2004

An approach for calculating the reliability of a rail with respect to elastic‐plastic work of the material is presented. The algorithm integrates the random nature of static and dynamic load with elastic‐plastic strains of the structure. The rail is modelled as a beam of infinite length founded on a rigid sleepers and visco‐elastic soil. The rail is loaded by a moving train in which the locomotive and railway cars are modelled by random point forces. The approach presented can be useful in reliability analysis of railway rails. Numerical examples have been provided.
Application of the Stochastic Renewal Processes in the Dynamics of Beams under Moving Load
Authors: Śniady P. , Sieniawska R. , Żukowski S.
Published: June 2004

The problem of stochastic dynamics of elastic beams of deterministic parameters loaded by the trafic flow is considered. Each vehicle is modelled by one or more random point forces travelling with the same constant speed. As a model of vehicle arrivals the renewal stochastic processes are adopted. An analytical technique is developed to determine the two first probabilistic characteristics of the beams response. Numerical examples are provided.
Crack Identification as an Optimization Task
Authors: Engelhardt M. , Stavroulakis G.E. , Antes H.
Published: June 2004

In this paper, crack and hole identification problems are studied. From the knowledge about the reflected wave forms of an embedded crack, an identification may be performed by an evolutionary strategy or by a neural network. This approach corresponds to a generalization of the impact‐echo nondestructive evaluation technique. The numerical solution of the two‐dimensional elastodynamical problem, i.e., to determine the reflected waveforms, is performed by means of boundary element techniques.
Optimal design of an ellipsoidal head of a pressure cylindrical vessel
Authors: Magnucki Krzysztof , Lewinski Jerzy
Published: June 2004

The subject of analysis is a stress concentration problem in a circular cylindrical vessel with ellipsoidal heads. The region of the junction of ellipsoidal and cylindrical shells is subject to stress concentration. Intensity of the concentration depends, first of all, on relative convexity of the ellipsoidal head, and the ratio of thicknesses of the shells. Based on the boundary disturbance theory the stress state in this cylindrical vessel was analytically described. Optimal ellipsoidal heads were determined on the grounds of three optimisation criteria.
Multi‐grid solver for the p‐version of the fem.
Authors: Beuchler Sven
Published: June 2004

In this paper we propose a pre‐conditioner for an element stiffness matrix of the p‐version of the fem in two dimensions. We prove that the condition number of the preconditioned system matrix is bounded by a constant independent of the polynomial degree. The origin of this pre‐conditioner is the multi‐grid method.
Bounds for the Effective Interest Rate for Constant, Periodic Annuities
Authors: Boese F. G.
Published: June 2004

For the title's financial credit class, arbitrary tight bounds for the effective interest rate, evaluable on (+, −, ∗︁, /,√)‐pocket calculators, are propounded. Starting with an initial bound with at most 0.85% relative error, in each refinement step about 61% more valid decimal places are won.
A multi‐level solution of scalar and vectorial interpolation problems based on iterated elliptic operators
Authors: Gáspár Csaba
Published: June 2004

One of the most popular methods to solve scattered data interpolation problems is the method of radial basis functions. However, it leads to a linear system with large, dense and ill‐conditioned matrix, which causes severe numerical difficulties. Here a relatively new approach is presented which completely avoids the large and dense matrices and significantly reduces the computational cost. The interpolation problem is converted to a higher order (typically to an iterated elliptic) partial differential equation supplied with the interpolation condition as special boundary conditions. This new problem is well‐posed in a suitable Sobolev space and can be solved by using robust, multi‐level methods. The approach is generalized also to vectorial interpolation problems, where the interpolation vector field is assumed to satisfy some additional conditions e.g. it is irrotational or divergence‐free.
Relationship Between Geršgorin‐type Theorems for Certain Subclasses of H‐Matrices
Authors: Cvetković Ljiljana , Kovačević Maja , Kostić Vladimir
Published: June 2004

It is well known that the eigenvalue inclusion domain can be obtained by Geršgorin theorem. It is also known that the Geršgorin theorem is equivalent to the statement that each strictly diagonally dominant (SDD) matrix is nonsingular. Similarly, statements about nonsingularity of some classes of matrices, which are generalizations of SDD class, produce new Geršgorin‐type theorems for eigenvalue inclusion domain. In this paper we will consider some subclasses of H‐matrices and corresponding (Geršgorin‐type) eigenvalue inclusion theorems. Finally, we will establish relationship between given inclusion domains.
Iterative Method with the Preconditioner (I + Smax) for H‐Matrices
Authors: Kostić Vladimir , Cvetković Ljiljana
Published: June 2004

In 2002 Kotakemori et al. have reported the Modified Gauss‐Seidel method with a preconditioner (I + Smax). The convergence of the new method they investigated only for Z‐matrices, for which the new method can be superior to other iterative methods. But, in the case of H‐matrices this method can be superior to the others, too. In this paper we will give some sufficient conditions for the convergence in the case of H‐matrices.
Special preconditioners for solution of transport‐dominated convectiondiffusion problem
Authors: Krukier L.A. , Lapshina O.A. , Krukier B.L.
Published: June 2004

Special class of preconditioners based on skew‐symmetric part of the matrix have been created for CG and BiCG type's methods. Theoretical and numerical investigation was carried out by the model of the linear algebraic equation system generated by finite‐difference approximation of the convection‐diffusion equation.
Energy conservation in modified Nyström methods for separable Hamiltoniansystems
Authors: Arnold Martin , Pfeiffer Andreas
Published: June 2004

Numerical integration methods that preserve structural properties of time dependent di.erential equations have often improved stability and smaller errors in long‐term simulations than classical standard methods like Runge–Kutta or BDF. In the present paper an energy conserving Galerkin type approach of Betsch and Steinmann is generalized to modified Nyström methods for separable Hamiltonian systems. The bene.ts of this new class of methods are illustrated by numerical tests for a benchmark problem from celestial mechanics.
Implicit Extension of Taylor Series Method with Numerical Derivatives
Authors: Molnárka Gy. , Miletics E.
Published: June 2004

The Taylor series method is one of the earliest analytic‐numeric algorithms for approximate solution of initial value problems for ordinary differential equations. The main idea of the rehabilitation of these algorithms is based on the approximate calculation of higher order derivatives using well‐known technique for the partial differential equations. The implicit extension based on a collocation term added to the explicit truncated Taylor series. This idea is different from the general collocation method construction, which led to the implicit R‐K algorithms [1].
H−1 LSFEM for Fluid‐Structure Problems
Authors: Kayser‐Herold Oliver , Matthies Hermann G.
Published: June 2004

The instationary incompressible Navier‐Stokes equations, which appear in the context of a instationary fluid‐structure problem are solved with a Space‐Time LSFEM formulation. Convergence rates of the proposed scheme are examined using the Taylor vortex.
Algebraic Multigrid Preconditioners for Sparse Approximations of Boundary Element Matrices
Authors: Langer U. , Pusch D. , Reitzinger S.
Published: June 2004

This paper presents new algebraic multigrid preconditioners for sparse representations of boundary element matrices which arise from the so‐called adaptive‐cross‐approximation to dense boundary element matrices resulting from the standard collocation, or Galerkin boundary element discretization of the single layer potential operator.
The approximate solution of integro‐ differential equations
Authors: Takaci Djurdjica
Published: June 2004

We consider a class of partial integro‐differential equations with appropriate conditions and its corresponding equation in the field of Mikusiński operators. As is usual in numerical analysis, we construct the corresponding difference equation, determine its solution, analyze its character and treat it as the approximate solution of the considered problem. We also estimate the error of approximation.
Genetic lineage of poorly differentiated gastric carcinoma with a tubular component analysed by comparative genomic hybridization
Authors: Peng Dun‐Fa , Sugihara Hiroyuki , Mukaisho Ken‐ichi , Ling Zhi‐Qiang , Hattori Takanori
Published: June 2004

Analysis of cell lineage is based on the use of genetic markers inherent to the lineage to be analysed. The breakpoints of unbalanced translocations, and the pattern of chromosomal loss/gain determined by comparative genomic hybridization (CGH), have been previously used to demonstrate lineages in diffuse‐type gastric carcinoma. Signet ring cell carcinoma was shown to progress to poorly differentiated adenocarcinoma, and early diffuse‐type gastric carcinoma to advanced diffuse‐type gastric carcinoma. The present study focuses on poorly differentiated adenocarcinoma with a tubular component to clarify its derivation. CGH and array CGH were applied to DNA extracted from multiple portions of individual tumours and amplified by degenerate oligonucleotide‐primed (DOP) PCR and the changes common to the samples in each tumour (stemline changes) were compared between the tumours with and those without a tubular component. Within individual tumours, the samples from the tubular component and those from the other components had common stemline changes and a very similar frequency pattern of chromosomal changes, indicating their common derivation. Frequent stemline changes were 8q+, 7p+, 3q+, 20q+, and 10p+, and these were different from those in the tumours without a tubular component. It was noticed that there were two subgroups in the tumours with a tubular component: one with 5p+, 6p+, 7p+, and 10p+, and the other without these changes. The latter had cytogenetic and clinicopathological features similar to those of the tumours without a tubular component. Analysis of the clonal evolution process by constructing dendrograms for each tumour gave results consistent with the notion that the latter subgroup may derive from signet ring cell carcinoma and the former from tubular adenocarcinoma. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Gastric B‐cell mucosa‐associated lymphoid tissue (MALT) lymphoma in an animal model of ‘Helicobacter heilmannii’ infection
Authors: O'Rourke JL , Dixon MF , Jack A , Enno A , Lee A
Published: June 2004

While Helicobacter pylori is accepted as the dominant human gastric bacterial pathogen, a small percentage of human infections have been associated with another organism, commonly referred to as ‘Helicobacter heilmannii’, which is more prevalent in a range of animal species. This latter bacterium has been seen in association with the full spectrum of human gastric diseases including gastritis, peptic ulceration, and gastric carcinomas, including gastric B‐cell mucosa‐associated lymphoid tissue (MALT) lymphoma. This study describes an analysis of the pathogenic potential of a number of ‘H heilmannii’ isolates in an animal model of gastric MALT lymphoma. BALB/c mice were infected with ten different ‘H heilmannii’ isolates originating from both human and animal hosts. The animals were examined at various time points for up to 28 months after infection. The infected animals initially developed a chronic inflammatory response within 6 months. This histological response increased in severity with the length of infection, with the development of overt lymphoma in some animals 18 months after infection. MALT lymphomas were detected in up to 25% of the infected animals. The prevalence of lymphoma was dependent on the length of infection and the origin of the infecting isolates. A range of other histological features accompanied the lymphocytic infiltration, including invaginations of the gastric epithelium and associated hyperplastic tissue, mucus metaplasia, and a small number of diffuse large B‐cell lymphomas. The ability to manipulate experientially the presence of the bacterium in the animal model will allow further studies examining the role of antigen drive in the development of Helicobacter‐associated MALT lymphoma. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Automated methods for improved protein identification by peptide mass fingerprinting
Authors: Levander Fredrik , Rögnvaldsson Thorsteinn , Samuelsson Jim , James Peter
Published: June 2004

In order to maximize protein identification by peptide mass fingerprinting noise peaks must be removed from spectra and recalibration is often required. The preprocessing of the spectra before database searching is essential but is time‐consuming. Nevertheless, the optimal database search parameters often vary over a batch of samples. For high‐throughput protein identification, these factors should be set automatically, with no or little human intervention. In the present work automated batch filtering and recalibration using a statistical filter is described. The filter is combined with multiple data searches that are performed automatically. We show that, using several hundred protein digests, protein identification rates could be more than doubled, compared to standard database searching. Furthermore, automated large‐scale in‐gel digestion of proteins with endoproteinase LysC, and matrix‐assisted laser desorption/ionization‐time of flight (MALDI‐TOF) analysis, followed by subsequent trypsin digestion and MALDI‐TOF analysis were performed. Several proteins could be identified only after digestion with one of the enzymes, and some less significant protein identifications were confirmed after digestion with the other enzyme. The results indicate that identification of especially small and low‐abundance proteins could be significantly improved after sequential digestions with two enzymes.
Phenol radical cations and phenoxyl radicals in electron transfer from the natural phenols sesamol, curcumin and trolox to the parent radical cations of 1‐chlorobutane
Authors: Joshi R. , Naumov S. , Kapoor S. , Mukherjee T. , Hermann R. , Brede O.
Published: June 2004

The free electron transfer from sesamol, curcumin and trolox to solvent (1‐chlorobutane) radical cations was studied. The solutes (ArOH) react with BuCl⋅+ at diffusion‐controlled rates (∼1010 dm3 mol−1 s−1) resulting, simultaneously, in phenol‐type radical cations (ArOH⋅+) and phenoxyl radicals (ArO⋅) with an ArOH⋅+/ArO⋅ ratio  > 1;1. It was found that the kinetics are markedly affected by the different substituents on the aromatic ring of ArOH⋅+. The various ArOH⋅+ react with triethylamine with rate constants of ∼109 dm3 mol−1 s−1, whereas ethanol and dioxane are ineffective as cation scavengers. The effect of substituents on the electron transfer and the ArOH⋅+/ArO⋅ ratio is discussed on the basis of experimental data and quantum chemical calculations. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis and characterization of secondary‐amine‐functional microparticles
Authors: Altintaş E. Banu , Kiliç Soner
Published: June 2004

Secondary‐amine‐functional microparticles were prepared in the range of 50–250 μm through the suspension polymerization of styrene, divinylbenzene (DVB), and 2‐(tert‐butylamino)ethyl methacrylate (tBAEMA). This study focused on the effects of the DVB, tBAEMA, initiator, and stabilizer concentrations and shaking rate on the experimental amine content, swelling ratio, average particle size, and particle size distribution. The suspension polymerization experiments were carried out in two different systems. In the first system, an organic phase, including the monomers and initiator, was dispersed in an aqueous medium in the presence of Al2(SO4)3. Al2(SO4)3, in the presence of an amine monomer (pH ∼ 10), formed colloidal Al(OH)3, which built a nonsticky layer on the surface of the polymerizing droplets that prevented them from coalescing and aggregating. Individual and spherical particles within the range of 50–200 μm were obtained by this polymerization method. The second method was similar to the first polymerization protocol, except that a certain amount of sodium dodecyl sulfate was added as a costabilizer in the presence of Al2(SO4)3. In these experiments, individual and spherical particles were obtained within the range of 130–250 μm. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem: 3708–3719, 2004
Impacts of neuroimaging on psycho‐oncology
Authors: Tashiro Manabu
Published: June 2004

Non‐invasive neuroimaging has become important in the field of psycho‐oncology. Positron emission tomography (PET) is a highly advanced form of scintigraphy and used for observation of regional tissue activities such as metabolism and perfusion. Nowadays, PET measurement of glucose consumption has been widely used not only for cancer diagnosis but also for evaluation of brain activity in various psychiatric and neurological disorders. Recently, it has been used for evaluation of relatively mild depression among cancer patients. In addition, magnetic resonance imaging (MRI) has been used for detection of brain metastasis in cancer patients, but also useful for evaluation of stressful events by measuring the sizes of tiny neural structures such as hippocampus and amygdala.

In this report, recent findings of non‐invasive neuroimaging in cancer patients are overviewed, putting emphasis on the possible impacts of neuroimaging on psycho‐oncology. Copyright © 2004 John Wiley & Sons, Ltd.
Evaluation of a Protocol for Postmortem Examination of Stillbirths and Neonatal Deaths with Congenital Anomalies
Authors: Cernach Mirlene C.S.P. , Patrício Francy R.S. , Galera Marcial F. , Moron Antonio F. , Brunoni Decio
Published: June 2004

A study was conducted on 75 perinatal deaths with congenital anomalies through clinical, radiographic, cytogenetic, and autopsy evaluation, and the diagnoses of 72 patients (96%) were determined. In 11 patients with chromosomal anomalies, the cytogenetic study was sufficient to determine the diagnosis and the reproductive risk. In these cases, the value of the autopsy results resided above all in the description of the clinical variability. Radiographic evaluation was the best method to establish a diagnosis of skeletal dysplasias (14.7%). Furthermore, the X-rays showed small skeletal defects which are difficult to see on dissection. The clinical genetic evaluation with a detailed description of the phenotype and anthropometric exam, performed by a clinical geneticist, and the autopsy with gross and microscopic evaluation, facilitated the diagnoses of 50 cases (66.7%). We concluded that, in perinatal death with congenital anomalies, the teamwork of clinical geneticists and fetal pathologists increases the probability of determining the etiological diagnosis. This is essential to define the parents' reproductive risk, thus contributing to primary prevention of congenital anomalies.
Rhabdomyosarcoma Arising in the Hand or Foot: A Clinicopathologic Analysis
Authors: Miller Dylan V. , Coffin Cheryl M. , Zhou Holly
Published: June 2004

Rhabdomyosarcomas (RMS) arising at different anatomic sites have distinct clinicopathologic features that affect prognosis and outcome. RMS arising in the extremities generally have a worse prognosis. Case reports and anecdotal experience suggests the possibility that RMS of the hand or foot (RMSHF) may behave even more aggressively than RMS elsewhere in the extremities. This study describes clinicopathologic features and outcome of RMSHF. Charts and pathologic material from RMSHF cases from institutional files over a 32-year interval were reviewed. Additional cases from published reports and series over a 42-year interval were identified by a MEDLINE search. Pertinent clinicopathologic features for each case were compiled. Survival analysis and other data from these patients were compared with previously reported statistics in the literature for RMS at other anatomic sites, including elsewhere in the extremities. Six patients from the institutional files and 46 from published reports were identified. A number of adverse prognostic indicators were observed in the majority of these patients including alveolar morphology (86%) and distant metastasis at presentation (63%). Despite the aggressive nature of these tumors, the majority were smaller than 5 cm (61%). A propensity was observed for metastases to unusual sites such as breast, ovary, testis, pancreas, and kidney. The median survival was 19 months, and the 5-year survival was 27%. While these may reflect a constellation of findings related to site, it is also possible that alveolar histology is the main influence. RMSHF can present as a very small primary tumor with clinically evident or occult metastatic disease. Whether this reflects the location, the predominantly alveolar histologic type, or a molecular genetic subtype will require further analysis. Patients presenting with RMSHF should be thoroughly evaluated for occult metastases at the time of diagnosis and followed closely throughout treatment for subsequent involvement of unusual sites.
Spatial heterogeneity and structure of bird populations: a case example with the eagle owl
Authors: Penteriani Vincenzo , Delgado María del Mar , Gallardo Max , Ferrer Miguel
Published: June 2004

If individuals of the same population inhabit territories different in landscape structure and composition, experiencing habitat‐specific demographic rates, then the landscape features become major determinants of the overall population characteristics. Few studies have tested how habitat‐specific demography interacts with landscape heterogeneity to affect populations of territorial species. Here we report a 29‐year study of an eagle owl (Bubo bubo) population in southern France. The aim of this study was to analyse how habitat heterogeneity could affect density and breeding performance. Mean productivity for the overall sample was 1.69±0.76 fledglings per breeding pair and, after controlling for year effect, significant differences between territories were detected for productivity. A positive correlation was found between the percentage of pairs producing 50% of the annual fledged young (an index of the distribution of fecundity among nesting territories) and the mean reproductive outputs, that is the heterogeneous structure of the population determined that most/all pairs contributed to the annual production of young during good years, but the opposite during poor years (i.e. fewer pairs produced the majority of fledglings). Mean reproductive output was positively affected by percentage of open country and diet richness. Although other factors different to territory quality could affect demography parameters (e.g. quality of breeders), our results clearly showed a significant correlation between landscape features and population productivity.
Chance and adaptation in the evolution of island bumblebee behaviour
Authors: Chittka Lars , Ings Thomas C. , Raine Nigel E.
Published: June 2004

We used a population biological approach to assist our understanding of the evolution of behaviour, with island bumblebees as our model system. The widespread European speciesBombus terrestrisoccurs on all major Mediterranean, and some Atlantic islands. Bees from different populations differ in a variety of behavioural traits, including floral colour preferences, flower detection, and learning behaviour. We attempted to correlate these behavioural differences with each population's environment, but could not find straightforward adaptive explanations. We also performed reciprocal transplant studies to compare nectar foraging performance of bees from three different populations, but found that non‐native bees consistently outcompeted native bees. Thus, we consider genetic drift, exaptation, and pleiotropy as possible alternative explanations to a strictly adaptive explanation for between population behavioural differences in bumblebees.
Community assembly along a species pool gradient: implications for multiple‐scale patterns of species diversity
Authors: Fukami Tadashi
Published: June 2004

Various ecological processes influence patterns of species diversity at multiple spatial scales. One process that is potentially important but rarely considered is community assembly. I assembled model communities using species pools of differing size to examine how the history of community assembly may affect multi‐scale diversity patterns. The model contained three scales at which diversity could be measured: local community, metacommunity, and species pool. Local species saturation occurred, as expected from the competition and predation built in the model. However, local communities did not become resistant to invasions except when the species pool was very small. Depending on dispersal rate and trophic level, the larger the species pool, the harder it was to predict which species invades which local community at a given time. Consequently, local‐community dissimilarity maintained by assembly history increased linearly with pool size, even though local diversity was decoupled from pool size. These results have two implications for multi‐scale diversity patterns. First, assembly history may provide an explanation for scale‐dependent relationships between local and regional diversity: assembly causes the relationship to be curvilinear at one scale (local community), while linear at another (metacommunity). Second, assembly history influences how γ‐diversity is partitioned into α‐ and β‐diversity: assembly causes the relative contribution of β to increase with pool size. Overall, this study suggests that community assembly history interacts with species pool size to regulate multi‐scale patterns of species diversity.
Modeling spatial dynamics of episodic and synchronous reproduction by plant populations: the effect of small‐scale pollen coupling and large‐scale climate
Authors: Satake Akiko
Published: June 2004

Many plant species show masting, intermittent and synchronized reproduction at population level. In the present paper, we review the resource‐based model providing a theoretically plausible physiological mechanism underlying masting. In the model, a non‐linear allocation of energy reserves is considered: plants accumulate photosynthate every year, produce flowers when the energy reserve level exceeds a threshold, and set seeds at a rate limited by pollen availability. The model predicted that individual plants alter their reproductive dynamics from annual to intermittent depending on how heavily the plant invests resource in reproduction. When fruit production is limited by the availability of outcross pollen, a plant population showed diverse reproductive behavior such as completely synchronized or desynchronized reproduction. Spatial scale of reproductive synchrony tended to be a few times larger than the range of direct pollen exchange. Impact of climatic fluctuation correlated at a large spatial scale was also investigated as an alternative synchronizing factor. The variation in annual productivity and the reproductive threshold induced from climatic fluctuation was accounted for by incorporating an additional term in the model. When plants show a 2 year reproductive cycle, highly synchronized reproduction at a regional scale was induced due to correlated environmental forcing, but reproductive synchrony with long intermast periods was realized only when pollen coupling and environmental forcing were at work. These results suggest that distance‐dependent processes, such as pollen exchange between nearby trees, induce synchrony at a local scale and external environmental forcing correlated at geographically large scales works to strengthen and maintain such a synchrony.
Additive and non‐additive effects from a larger spatial scale determine small‐scale densities in a web spiderNeriene brongersmai
Authors: Takada Mayura , Miyashita Tadashi
Published: June 2004

We examined 15 populations ofNeriene brongersmai, a common sheet‐web spider inhabiting cedar forest floor, to find out how density at a small spatial scale (patch level) is determined by processes operating at this scale as well as those from a larger spatial scale (population level). Here we focus on two types of large‐scale effects that may influence small‐scale density: an additive effect that changes the density at patch level; and a non‐additive effect that changes the relationship between the density and its limiting factor at the patch level. ANCOVA showed that patch‐level density of this spider was positively correlated with web‐site availability at this level, but the density with a given amount of web‐site differed among populations (cedar forests), indicating the existence of an additive large‐scale effect. Multiple regression analysis showed that web‐site availability at a population level explained the additive large‐scale effect well, but prey availability and forest size did not. It seemed likely that increased web‐site availability may have reduced the mortality of spiders while moving to a new web‐site, and hence increased population density. A non‐additive large‐scale effect was also revealed: i.e. the relationship between density and web‐site availability at the patch level tended to be stronger in populations with a greater additive large‐scale effect. Higher intraspecific competition for web‐sites in these populations appeared to have strengthened this relationship.
A field assessment of reproductive seasonality in the threatened wild Namaqua dune mole‐rat (Bathyergus janetta)
Authors: Herbst M. , Jarvis J. U. M. , Bennett N. C.
Published: June 2004

The Namaqua dune mole‐rat Bathyergus janetta breeds seasonally, producing up to two litters during the early summer in the Cape. Females exhibit elevated urinary progesterone and oestradiol‐17β concentrations and males raised concentrations of testosterone, these correlate with the onset of the seasonal winter rainfall. The rains moisten the soil allowing excavation and provide the mole‐rats with the opportunity not only to extend burrow systems but also to search for mates. An increased incidence of hindfoot drumming and visitations to neighbouring burrow systems occurs during this period. Plural occupancy of burrows by adult mole‐rats was found during the onset of the winter, and pups, lactating and pregnant females were caught at the end of October and November (early Cape summer). Pups develop rapidly and their eyes open after c. 1 week. Pup body mass increases exponentially from birth to about 70 days. Inter‐sibling aggression increases progressively and after c. 60 days captive‐born pups had to be separated, suggesting that in the wild they would have dispersed.
Calcium availability affects bone growth in nestlings of free‐living great tits (Parus major), as detected by plasma alkaline phosphatase
Authors: Tilgar Vallo , Mänd Raivo , Ots Indrek , Mägi Marko , Kilgas Priit , Reynolds S. James
Published: June 2004

Recent studies have revealed that calcium limitation of avian reproduction may be a widespread phenomenon, affecting both egg properties and chick development. The effect of calcium shortage on the final body size of fledglings is usually rather weak, possibly owing to compensatory growth. Achieving full skeletal size is not, however, a reliable indication of complete ossification and it is possible that chicks with similar tarsus lengths are in different stages of skeletal development. We hypothesized that measuring plasma activity of the bone alkaline phosphatase (ALP), a highly specific marker for bone calcification, may reveal subtle developmental differences in full‐grown fledglings, having experienced different levels of calcium availability during growth. In two seasons, a number of pairs of great tit Parus major were provided with calcium‐rich material during the nestling period, while others were not supplemented (controls). While no significant differences in size of fledglings were detected between groups, bone‐ALP activity at the pre‐fledging stage was lower in the calcium‐provided nestlings than in the control nestlings. This may indicate that supplemented chicks had completed the rapid phase of bone formation, but this process was delayed in controls. Measuring ALP as a marker of skeletal development expands our knowledge of how delayed skeletal development of chicks can result in protraction of the nestling period, thereby reducing the breeding success of adult birds.
Threshold height (h′F)c for the meridional wind to play a deterministic role in the bottom side equatorial spread F and its dependence on solar activity
Authors: Jyoti N. , Devasia C. V. , Sridharan R. , Tiwari Diwakar
Published: June 2004

Detailed investigations have been carried out on the occurrence of bottom side Equatorial Spread F (ESF) and the thermospheric meridional wind characteristics just before the former's initiation using ground based ionospheric data corresponding to the equinoctial periods of 1993–1998, from Trivandrum (8.5°N, 76.5°E, dip = 0.5°N) and Sriharikota (13.7°N, 80.2°E, dip ∼ 10°N) in the Indian longitudes. Critical analysis of the base height of the F‐region h′F at the time of triggering of ESF and the polarity of the meridional winds revealed that, if the h′F is above a certain level ESF occurred under both equatorward and poleward wind conditions. Below that level, ESF occurred only when equatorward winds were present implying that the equatorward winds must somehow be able to offset the reduced growth rate of the plasma instability responsible for ESF. A plausible explanation linking Equatorial Ionization Anomaly (EIA) and the consequent Equatorial Temperature and Wind Anomaly (ETWA) and the consequent neutral dynamics effectively enabling the instability even at lower height has been offered. The threshold height (h′F)c gleaned out on the basis of the polarity of the meridional winds has been shown to bear a linear relation to the solar activity and sheds light on the enigmatic short and long term variability of ESF.
Specific 14-3-3 isoform detection and immunolocalization in prion diseases
Authors: Baxter H. C. , Fraser J. R. , Liu W.-G. , Forster J. L. , Clokie S. , Steinacker P. , Otto M. , Bahn E. , Wiltfang J. , Aitken A.
Published: June 2004

14-3-3 proteins are involved in signalling processes in neuronal cells. Using isoform-specific antibodies we have examined the variation in 14-3-3 isoform neurolocation in normal and scrapie-infected murine brain and show that in defined areas of the brain there are significant changes associated with the pathology of the disease process. The appearance of 14-3-3 proteins in the cerebrospinal fluid (CSF) is a consequence of neuronal disease and the detection of specific isoforms of the 14-3-3 proteins in the CSF is characteristic of some neurodegenerative diseases. In this study, monitoring specifically for theγ 14-3-3 isoform in the CSF by both Western-blot analysis and ELISA we can show a level of correlation between the assays.