bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustic and auditory phonetics: the adaptive design of speech sound systems
Authors: Diehl Randy L
Published: September 2007

Speech perception is remarkably robust. This paper examines how acoustic and auditory properties of vowels and consonants help to ensure intelligibility. First, the source–filter theory of speech production is briefly described, and the relationship between vocal-tract properties and formant patterns is demonstrated for some commonly occurring vowels. Next, two accounts of the structure of preferred sound inventories, quantal theory and dispersion theory, are described and some of their limitations are noted. Finally, it is suggested that certain aspects of quantal and dispersion theories can be unified in a principled way so as to achieve reasonable predictive accuracy.
Listening to speech in the presence of other sounds
Authors: Darwin C.J
Published: September 2007

Although most research on the perception of speech has been conducted with speech presented without any competing sounds, we almost always listen to speech against a background of other sounds which we are adept at ignoring. Nevertheless, such additional irrelevant sounds can cause severe problems for speech recognition algorithms and for the hard of hearing as well as posing a challenge to theories of speech perception. A variety of different problems are created by the presence of additional sound sources: detection of features that are partially masked, allocation of detected features to the appropriate sound sources and recognition of sounds on the basis of partial information. The separation of sounds is arousing substantial attention in psychoacoustics and in computer science. An effective solution to the problem of separating sounds would have important practical applications.
Fronto-temporal brain systems supporting spoken language comprehension
Authors: Tyler Lorraine K , Marslen-Wilson William
Published: September 2007

The research described here combines psycholinguistically well-motivated questions about different aspects of human language comprehension with behavioural and neuroimaging studies of normal performance, incorporating both subtractive analysis techniques and functional connectivity methods, and applying these tasks and techniques to the analysis of the functional and neural properties of brain-damaged patients with selective linguistic deficits in the relevant domains. The results of these investigations point to a set of partially dissociable sub-systems supporting three major aspects of spoken language comprehension, involving regular inflectional morphology, sentence-level syntactic analysis and sentence-level semantic interpretation. Differential patterns of fronto-temporal connectivity for these three domains confirm that the core aspects of language processing are carried out in a fronto-temporo-parietal language system which is modulated in different ways as a function of different linguistic processing requirements. No one region or sub-region holds the key to a specific language function; each requires the coordination of activity within a number of different regions. Functional connectivity analysis plays the critical role of indicating the regions which directly participate in a given sub-process, by virtue of their joint time-dependent activity. By revealing these codependencies, connectivity analysis sharpens the pattern of structure–function relations underlying specific aspects of language performance.
Sustainable agriculture and plant diseases: an epidemiological perspective
Authors: Gilligan Christopher A
Published: September 2007

The potential for modern biology to identify new sources for genetical, chemical and biological control of plant disease is remarkably high. Successful implementation of these methods within globally and locally changing agricultural environments demands new approaches to durable control. This, in turn, requires fusion of population genetics and epidemiology at a range of scales from the field to the landscape and even to continental deployment of control measures. It also requires an understanding of economic and social constraints that influence the deployment of control. Here I propose an epidemiological framework to model invasion, persistence and variability of epidemics that encompasses a wide range of scales and topologies through which disease spreads. By considering how to map control methods onto epidemiological parameters and variables, some new approaches towards optimizing the efficiency of control at the landscape scale are introduced. Epidemiological strategies to minimize the risks of failure of chemical and genetical control are presented and some consequences of heterogeneous selection pressures in time and space on the persistence and evolutionary changes of the pathogen population are discussed. Finally, some approaches towards embedding epidemiological models for the deployment of control in an economically plausible framework are presented.
Introduction. The perception of speech: from sound to meaning
Authors: Moore Brian C.J , Tyler Lorraine K , Marslen-Wilson William
Published: September 2007

Spoken language communication is arguably the most important activity that distinguishes humans from non-human species. This paper provides an overview of the review papers that make up this theme issue on the processes underlying speech communication. The volume includes contributions from researchers who specialize in a wide range of topics within the general area of speech perception and language processing. It also includes contributions from key researchers in neuroanatomy and functional neuro-imaging, in an effort to cut across traditional disciplinary boundaries and foster cross-disciplinary interactions in this important and rapidly developing area of the biological and cognitive sciences.
Methods for obtaining the strain-free lattice parameter when using diffraction to determine residual stress
Authors: Withers P. J. , Preuss M. , Steuwer A. , Pang J. W. L.
Published: September 2007

The determination of residual stress by diffraction depends on the correct measurement of the strain-free lattice spacing d_{hkl}^0, or alternatively the enforcement of some assumption about the state of strain or stress within the body. It often represents the largest uncertainty in residual stress measurements since there are many ways in which the strain-free lattice spacing can vary in ways that are unrelated to stress. Since reducing this uncertainty is critical to improving the reliability of stress measurements, this aspect needs to be addressed, but it is often inadequately considered by experimenters. Many different practical strategies for the determining of d_{hkl}^0 ordrefhave been developed, some well known, others less so. These are brought together here and are critically reviewed. In practice, the best method will vary depending on the particular application under consideration. Consequently, situations for which each method are appropriate are identified with reference to practical examples.
High-resolution three-dimensional mapping of individual grains in polycrystals by topotomography
Authors: Ludwig Wolfgang , Lauridsen Erik Mejdal , Schmidt Soeren , Poulsen Henning Friis , Baruchel José
Published: September 2007

By orienting a crystal grain with its diffraction vector along the sample rotation axis, it is possible to use powerful tomographic and topographic imaging techniques to reconstruct the three-dimensional grain shape inside a polycrystalline sample. The acquisition and reconstruction can be performed from projection images with the detector positioned either in the diffracted-beam or in the direct-beam position. In the first case, the projection data consist of a series of integrated, monochromatic beam X-ray diffraction topographs of the grain under investigation. In the second case, the corresponding diffraction contrast in the transmitted beam may be interpreted as an additional contribution to the X-ray attenuation coefficient of the material. This latter variant is restricted to grains with small orientation spread but offers the possibility to characterize simultaneously the three-dimensional grain shape and the absorption microstructure of the surrounding sample material. The contrast mechanism is sensitive to local strain fields and can, in certain cases, reveal details of the grain microstructure, such as the presence of second-phase inclusions. The methodology is successfully demonstrated on an aluminium polycrystal, with a resulting three-dimensional mapping accuracy better than 7 µm. The possibilities and limitations of the technique are listed and its performance relative to other three-dimensional mapping techniques is discussed.
Data reduction practice in X-ray reflectometry
Authors: Salah F. , Harzallah B. , van der Lee A.
Published: September 2007

Data reduction practice in X-ray reflectometry is described. The several approaches for applying certain corrections, such as background subtraction, geometrical effects and normalization, are compared and discussed. Two widely employed setups, one with beam knife-edge and one without, are compared with respect to a number of corrections to be applied.
The revenge of the Patterson methods. III.Ab initiophasing from powder diffraction data
Authors: Burla Maria Cristina , Caliandro Rocco , Carrozzini Benedetta , Cascarano Giovanni Luca , De Caro Liberato , Giacovazzo Carmelo , Polidori Giampiero , Siliqi Dritan
Published: September 2007

In the present paper, the third and last of a series (the first two papers were dedicated to the crystal structure solution of proteins), the Patterson superposition method, based on the use of the symmetry minimum function, has been applied to powder diffraction patterns. The method has been modified to take into account the special challenges of this kind of data and to optimize the performance of the approach. The new algorithms have been implemented in a computer program and applied also to single-crystal data of small and medium-size crystal structures. The experimental results have been compared with those obtainedviadirect methods, so enabling the role and the perspectives of these two approaches in the global phasing problem to be established, no matter what the experimental technique (powder or single-crystal diffraction) or the size of the structures (small, medium or macro-molecules).
A comparison of modern data analysis methods for X-ray and neutron specular reflectivity data
Authors: van der Lee A. , Salah F. , Harzallah B.
Published: September 2007

Data analysis methods for specular X-ray or neutron reflectivity are compared. The methods that have been developed over the years can be classified into different types. The so-called classical methods are based on Parrat's or Abelès' formalism and rely on minimization using more or less evolved Levenberg–Marquardt or simplex routines. A second class uses the same formalism, but optimization is carried out using simulated annealing or genetic algorithms. A third class uses alternative expressions for the reflectivity, such as the Born approximation or distorted Born approximation. This makes it easier to invert the specular data directly, coupled or not with classical least-squares or iterative methods using over-relaxation or charge-flipping techniques. A fourth class uses mathematical methods founded in scattering theory to determine the phase of the scattered waves, but has to be coupled in certain cases with (magnetic) reference layers. The strengths and weaknesses of a number of these methods are evaluated using simulated and experimental data. It is shown that genetic algorithms are by far superior to traditional and advanced least-squares methods, but that they fail when the layers are less well defined. In the latter case, the methods from the third or fourth class are the better choice, because they permit at least a first estimate of the density profile to be obtained that can be refined using the classical methods of the first class. It is also shown that different analysis programs may calculate different reflectivities for a similar chemical system. One reason for this is that the representation of the layers is either described by chemical composition or by scattering length or electronic densities, between which the conversion of the absorptive part is not straightforward. A second important reason is that routines that describe the convolution with the instrumental resolution function are not identical.
Grain-size distributions and grain boundaries of chalcopyrite-type thin films
Authors: Abou-Ras D. , Schorr S. , Schock H. W.
Published: September 2007

CuInSe2, CuGaSe2, Cu(In,Ga)Se2and CuInS2thin-film solar absorbers in completed solar cells were studied in cross section by means of electron-backscatter diffraction. From the data acquired, grain-size distributions were extracted, and also the most frequent grain boundaries were determined. The grain-size distributions of all chalcopyrite-type thin films studied can be described well by lognormal distribution functions. The most frequent grain-boundary types in these thin films are 60°−〈221〉tetand 71°−〈110〉tet(near) Σ3 twin boundaries. These results can be related directly to the importance of {112}tetplanes during the topotactical growth of chalcopyrite-type thin films. Based on energetic considerations, it is assumed that the most frequent twin boundaries exhibit a 180°−〈221〉tetconstellation.
Relationship between structure and optical properties of lithium triborate
Authors: Etxebarria J. , Ortega J. , Folcia C. L.
Published: September 2007

Measurements of the optical rotation of LiB3O5have been carried out using a high-accuracy universal polarimeter in the temperature range 298–503 K. The results have been analyzed within the framework of a point-dipole model for the optical rotation. Though the magnitude of the rotation is very small, its sign has been clearly determined and linked to the crystallographic structure. A slight modification of the point-dipole model also permits an explanation of the values of the second-order susceptibility coefficients for second-harmonic generation.
Toward fully fledged high-pressure macromolecular crystallography
Authors: Girard Eric , Dhaussy Anne-Claire , Couzinet Bernard , Chervin Jean-Claude , Mezouar Mohamed , Kahn Richard , Ascone Isabella , Fourme Roger
Published: September 2007

Pressure allows one to explore the energy landscape and the various conformations of macromolecules. This might be one of the most interesting prospects of combining macromolecular crystallography (MX) with pressure perturbation. This paper presents innovations in high-pressure macromolecular crystallography (HPMX). A new-generation diamond anvil cell extends the technical feasibility of HPMX experiments up to about 2.5 GPa (depending on the sample). Thanks to the large useful aperture (82°) provided by this cell and special loading techniques (use of splinter and/or multiple samples), HPMX can now be more readily applied to crystals with very anisotropic habits and/or low-symmetry space groups, as demonstrated by analysis of diffraction data collected at 140 MPa from orthorhombic urate oxidase crystals. The behaviour of hexagonal crystals of an octanucleotide was investigated up to 2 GPa.
Threading dislocations in domain-matching epitaxial films of ZnO
Authors: Liu W.-R. , Hsieh W. F. , Hsu C.-H. , Liang Keng S. , Chien F. S.-S.
Published: September 2007

The structures of high-quality ZnO epitaxial films grown by pulsed-laser deposition on sapphire (0001) without an oxygen gas flow were investigated by X-ray diffraction and transmission electron microscopy. The great disparity of X-ray diffraction line widths between the normal and in-plane reflections reveals the specific threading dislocation geometry of ZnO. Most threading dislocations are pure edge dislocations. From a combination of scattering and microscopic results, it is found that threading dislocations are not uniformly distributed in the ZnO films, but the films consist of columnar epitaxial cores surrounded by annular regions of edge threading dislocations in large density. The local surface morphology and capacitance signal obtained from atomic force and scanning capacitance microscopes indicate that the aggregation of threading dislocations leads to high interface traps at the annular regions.
Direct observation of elastic displacement modes by grazing-incidence X-ray diffraction
Authors: Prévot Geoffroy , Coati Alessandro , Croset Bernard , Garreau Yves
Published: September 2007

It is demonstrated that grazing-incidence X-ray diffraction is a direct tool for measuring the elastic displacement modes near the surface of a crystal. Due to the fact that X-ray diffraction is a Fourier transform of the electronic density, and thus, of the atomic positions, elastic displacement modes appear as additional spots in the reciprocal space. Their characteristics can be directly derived from the elastic constants of the material. Measuring the amplitude of the diffracted wave for these peaks allows direct determination of the force distribution at the surface, which is at the origin of the elastic displacements. Various examples of such determinations are given for self-organized surfaces and for vicinal surfaces.
Effect of texture on the intrinsic dissolution behaviour of acetylsalicylic acid and tolbutamide compacts
Authors: Tenho Mikko , Aaltonen Jaakko , Heinänen Paula , Peltonen Leena , Lehto Vesa-Pekka
Published: September 2007

Preferred orientation of crystallites,i.e.texture, is a common result when a sample with an irregular habit of particles is compacted to form a tablet. Since texturization alters the random distribution of the crystal planes on the surface of the compacted sample, the dissolution properties of highly texturized tablets could differ from the properties of a tablet with a less preferred orientation. Three batches from both acetylsalicylic acid and tolbutamide were recrystallized using different crystallization parameters to obtain powders with different texturization behaviour. Several X-ray diffraction procedures were used to characterize the texture and other crystallographic properties of the samples. The intrinsic dissolution profiles were measured using the channel flow technique. In addition, the attachment energy of the crystal planes lying on the surface of the compacts was calculated theoretically. The results indicate that the most texturized compacts had a clearly lower intrinsic dissolution rate than the compacts with a lower degree of preferred orientation. By combining the results of the texture measurements with the calculated attachment energy values, the surface energies of the samples could be estimated and the estimated energy values were in agreement with the results of the dissolution studies. Moreover, it was found that by using the results of the texture measurements, the habit of the sample particles can be successfully predicted.
Shake-and-Bakeon the grid
Authors: Miller Russ , Shah Naimesh , Green Mark L. , Furey William , Weeks Charles M.
Published: September 2007

Computational and data grids represent an emerging technology that allows geographically and organizationally distributed resources (e.g.computing and storage resources) to be linked and accessed in a fashion that is transparent to the user, presenting an extension of the desktop for users whose computational, data and visualization needs extend beyond their local systems. The New York State Grid is an integrated computational and data grid that provides web-based access for users from around the world to computational, application and data storage resources. This grid is used in a ubiquitous fashion, where the users have virtual access to their data sets and applications, but do not need to be made aware of the details of the data storage or computational devices that are specifically employed. Two of the applications that users worldwide have access to on a variety of grids, including the New York State Grid, are theSnBandBnPprograms, which implement theShake-and-Bakemethod of molecular structure (SnB) and substructure (BnP) determination, respectively. In particular, through our grid portal (i.e.logging on to a web site),SnBhas been run simultaneously on all computational resources on the New York State Grid as well as on more than 1100 of the over 3000 processors available through the Open Science Grid.
Canonical correlation and quantitative phase analysis of microdiffraction patterns in bone-tissue engineering
Authors: Guagliardi Antonietta , Giannini Cinzia , Ladisa Massimo , Lamura Antonio , Laudadio Teresa , Cedola Alessia , Lagomarsino Stefano , Cancedda Ranieri
Published: September 2007

A novel method is described that combines high-resolution scanning microdiffraction techniques, Rietveld quantitative phase analysis and a statistical method known as canonical correlation analysis (CCA). The method has been applied to a sample taken from a bone-tissue-engineered bioceramic porous scaffold implanted in a mouse for six months. The CCA technique allows the detection of those pixels throughout the investigated sample that best correlate with signal models. Besides the standard usage of this approach, which requires theoretical profiles as signal models, a novel application is presented here, which consists of picking the model spectra out of the experimental data set. Patterns representative of a reasonable range of phase compositions were selected among the huge number of two-dimensional patterns (folded in one-dimensional profiles) to extract quantitative phase fractions. At this stage, the CCA approach was also used to overcome the low Poisson statistic of signal models, so making Rietveld quantitative analysis more reliable. These patterns have been used as profile models for CCA. The final classification map, obtained by assigning the considered pixel to the model spectrum with the highest canonical coefficient, provides the spatial variation of phase concentration.
Advances inab initioprotein phasing by Patterson deconvolution techniques
Authors: Caliandro Rocco , Carrozzini Benedetta , Cascarano Giovanni Luca , De Caro Liberato , Giacovazzo Carmelo , Siliqi Dritan
Published: September 2007

New algorithms have been devised and implemented in the programSIR2007for the deconvolution of Patterson mapsviathe use of implication transformations and of the minimum superposition function. The new algorithms concern several practical aspects, such as the use of weighted Patterson syntheses to simplify the recognition of useful pivot peaks, the definition of a ranking criterion for them, the introduction of an early figure of merit to discard useless pivots and the fast Fourier transform transposition of theRELAXalgorithm, aiming to find the correct location when the current molecular model is translated with respect to the true position. The advantages of the new procedure have been assessed using a large set of test structures. The results have been analysed with respect to four parameters: the CPU time necessary for obtaining and recognizing the correct solution, the presence of heavy atoms, the complexity limit of the structures solvableab initio, and the data resolution limit.
Detailed analysis of gyroid structures in diblock copolymer thin films with synchrotron grazing-incidence X-ray scattering
Authors: Jin Sangwoo , Yoon Jinhwan , Heo Kyuyoung , Park Hae-Woong , Kim Jehan , Kim Kwang-Woo , Shin Tae Joo , Chang Taihyun , Ree Moonhor
Published: September 2007

In this study, a grazing-incidence X-ray scattering (GIXS) formula was derived for gyroid structures formed in thin films supported on substrates. Two-dimensional GIXS patterns were measured for gyroid structures formed in polystyrene-b-polyisoprene (PS-b-PI) diblock copolymer nanometre-scale thin films supported on silicon substrates, and a quantitative analysis of the obtained two-dimensional GIXS data was conducted with the scattering formula. This analysis provided details (lattice parameter, width of the PS phase, positional distortion factor, orientation and orientation distribution) of the gyroid structures developed in the diblock copolymer thin films that are not easily obtained using conventional techniques. Moreover, it was possible to simulate complete and detailed two-dimensional GIXS patterns with the determined structure parameters.
Monte Carlo simulation of the effect of counting losses on measured X-ray intensities
Authors: Ida T.
Published: September 2007

The statistical properties of intensities affected by counting loss based on conventional non-extended and extended dead-time models are examined by a Monte Carlo method. It has been confirmed that the variance of the counted pulses for the non-extended dead-time model with the rate of generated pulsesr and the dead-time τ is given by \sigma_{\rm non}^2 = \mu_{\rm non}/(1+r \tau)^2, while that for the extended dead-time model is given by \sigma_{\rm ext}^2 = \mu_{\rm ext} [1 - 2r\tau \exp(-r \tau)], as proposed by Laundy & Collins [(2003).J. Synchrotron Rad.10, 214–218], for the mean values of counted pulses μnonand μext, respectively. Practical formulae to estimate the statistical errors of the corrected intensities are also presented.
Analysis of binary outcomes with missing data: missing = smoking, last observation carried forward, and a little multiple imputation
Authors: Hedeker Donald , Mermelstein Robin J. , Demirtas Hakan
Published: September 2007

Aims  Analysis of binary outcomes with missing data is a challenging problem in substance abuse studies. We consider this problem in a simple two‐group design where interest centers on comparing the groups in terms of the binary outcome at a single timepoint.

Design  We describe how the deterministic assumptions of missing = smoking and last observation carried forward (LOCF) can be relaxed by allowing missingness to be related imperfectly to the binary outcome, either stratified on past values of the outcome or not. We also describe use of multiple imputation to take into account the uncertainty inherent in the imputed data.

Setting  Data were analyzed from a published smoking cessation study evaluating the effectiveness of adding group‐based treatment adjuncts to an intervention comprised of a television program and self‐help materials.

Participants  Participants were 489 smokers who registered for the television‐based program and who indicated an interest in attending group‐based meetings.

Measurements  The measurement of the smoking outcome was conducted via telephone interviews at post‐intervention and at 24 months.

Findings and conclusions  The significance of the group effect did vary as a function of the assumed relationship between missingness and smoking. The ‘conservative’ missing = smoking assumption suggested a beneficial group effect on smoking cessation, which was confirmed via a sensitivity analysis only if an extreme odds ratio of 5 between missingness and smoking was assumed. This type of sensitivity analysis is crucial in determining the role that missing data play in arriving at a study's conclusions.
A safe, sensible and social AHRSE: New Labour* and alcohol policy
Authors: Anderson Peter
Published: September 2007

When the Labour government came to power in the UK in 1997, it took over high and rising levels of alcohol consumption and alcohol‐related harm. Contrary to ‘old Labour’'s views on alcohol policy, New Labour did nothing to reverse this trend, and, if anything, exacerbated it. Since New Labour has been in power, alcohol has become 40% more affordable; consumption has increased by 14% and alcohol‐related deaths have increased by over 40%. New Labour viewed alcohol‐related harm as a question of individual responsibility and, as expressed in its long awaited 2004 alcohol harm reduction strategy (commonly known as AHRSE), viewed partnerships with the alcohol industry as the solution to reducing harm. Ten years on we have safe, sensible and social, the 3Ss, AHRSE's next steps. On first reading it would seem that the government has learnt nothing from its mistakes of the previous ten years, and in its approach to alcohol policy continues to disable the public interest. Nevertheless, there remain areas where science might inform policy, including health sector policy where there is an emphasis on early diagnosis and treatment, and transport policy, where reducing the legal blood alcohol level to the European Commission maximum recommended level of 0.5g/L is again on the agenda. The 3Ss propose an independent review of the evidence of the relationship between alcohol price, promotion and harm. However, unless this fully reviews the international evidence of the relationship between the economic and physical availability of alcohol, the marketing of alcohol and alcohol related harm, AHRSE and its successor will continue to be a recipe for ineffectiveness.
Assessing the quality of colorectal cancer care: do we have appropriate quality measures? (A systematic review of literature)
Authors: Patwardhan Meenal , Fisher Deborah A. , Mantyh Christopher R. , McCrory Douglas C. , Morse Michael A. , Prosnitz Robert G. , Cline Kathryn , Samsa Gregory P.
Published: September 2007

Rationale, aims and objectives  The burden of illness from colorectal cancer (CRC) can be reduced by improving the quality of care. Identifying appropriate quality measures is the first step in this direction. We identified process measures currently available to assess the quality of diagnosis and management of CRC. We also evaluated the extent to which these measures are ready to be implemented in clinical practice, and identified areas for future research.

Methods  We searched MEDLINE®, Cochrane Database of Systematic Reviews, and relevant grey literature. We identified 3771 abstracts and reviewed 74 articles that included quality measures for diagnosis or management of CRC. Measures from traditional quality improvement literature, and from epidemiological and other studies that included quality measures as part of their research agenda, were considered. In addition, we devised a summary rating scale (IST) to appraise the extent of a measure’s importance and usability, scientific acceptability and extent of testing.

Results  The coverage of general process measures in CRC is extensive. Most measures are important, but need to be developed and field‐tested. The best available measures relate to pathology and chemotherapy. No measures are available for assessing quality of management of stage IV rectal cancer and hepatic metastasis; chemotherapy for stage II colon cancer; and procedure notes.

Conclusions  There is an urgent need to refine existing measures and to develop scientifically accurate quality measures for a comprehensive assessment of the quality of CRC care. The role of the federal government and professional societies is critical in pursuing this goal.
Development and validation of a mobile computer anxiety scale
Authors: Wang Yi‐Shun
Published: September 2007

Although researchers have developed various scales for measuring users' computer anxiety or Internet anxiety, none of the literature has addressed the measurement of mobile computer anxiety (MCA). The purpose of this study is to develop and validate a multidimensional mobile computer anxiety scale (MCAS) based on previous research on computer anxiety and Internet anxiety. In this study, I introduce and define the construct of MCA, provide an empirical validation of the construct and its underlying dimensionality, develop a generic MCA scale with desirable psychometric properties and explore the scale's theoretical and practical applications. By analysing data from a sample of 287 respondents, this study proposes a 7‐factor, 38‐item MCAS. This empirically validated scale will be useful to researchers in developing and testing mobile learning (m‐learning) theories, as well as to educators and m‐learning managers in understanding an individual's MCA and in promoting the use of mobile computing and learning systems.
Automatic identification of seasonal transfer function models by means of iterative stepwise and genetic algorithms
Authors: Chiogna Monica , Gaetan Carlo , Masarotto Guido
Published: September 2007

Abstract. In this article, we introduce an automatic identification procedure for transfer function models. These models are commonplace in time‐series analysis, but their identification can be complex. To tackle this problem, we propose to couple a nonlinear conditional least‐squares algorithm with a genetic search over the model space. We illustrate the performances of our proposal by examples on simulated and real data.
Density estimation with locally identically distributed data and with locally stationary data
Authors: Klemelä Jussi
Published: September 2007

Abstract. We consider multivariate density estimation when the assumptions of identically distributed data or stationary data are relaxed to the assumptions of locally identically distributed data or locally stationary data. We assume that the distribution of the data is changing continuously as function of time. To estimate densities non‐parametrically with these local regularity conditions, we need time localization in addition to the usual space localization. We define a time‐localized kernel estimator that estimates the density non‐parametrically at any given point of time. The consistency of the time‐localized kernel estimator is proved and the rates of convergence of the estimator are derived under conditions on theβ‐andα‐mixing coefficients. Both the time‐series setting and spatial setting are covered.
Asymptotics for stationary very nearly unit root processes
Authors: Andrews Donald W. K. , Guggenberger Patrik
Published: September 2007

Abstract.  This article considers a mean zero stationary first‐order autoregressive (AR) model. It is shown that the least squares estimator and t statistic have Cauchy and standard normal asymptotic distributions, respectively, when the AR parameter ρn is very near to one in the sense that 1 − ρn = o(n−1).
PERMANENT GENETIC RESOURCES: Ten polymorphic microsatellite markers for the pygmy rabbit (Brachylagus idahoensis)
Authors: ESTES‐ZUMPF WENDY A. , RACHLOW JANET L. , WAITS LISETTE P.
Published: September 2007

We developed 10 polymorphic microsatellite loci for the pygmy rabbit (Brachylagus idahoensis). Nine of the 10 loci amplified reliably and had a low frequency of null alleles. Number of alleles per locus ranged from four to 12, and observed and expected heterozygosities ranged from 0.26 to 0.89 and from 0.63 to 0.88, respectively. These loci will be useful in determining population genetic structure and assessing patterns of gene flow in the pygmy rabbit.
PERMANENT GENETIC RESOURCES: Development of microsatellite markers in Rhinanthus angustifolius and cross‐species amplification
Authors: DUCARME V. , RISTERUCCI A. M. , WESSELINGH R. A.
Published: September 2007

Fifteen polymorphic microsatellite loci were developed from an enriched genomic library of the annual plant Rhinanthus angustifolius and characterized using 36 individuals. These markers provided high polymorphism ranging from two to 15 alleles per locus. Four loci showed significant departure from Hardy–Weinberg equilibrium, probably because of the occurrence of null alleles. No significant linkage disequilibrium was detected between pairs of loci. Tests of cross‐species transferability were performed on four congeners with a success rate of 100% in Rhinanthus minor, 93% in R. mediterraneus and R. glacialis, and 80% in R. alectorolophus. These microsatellite loci will be useful tools to study mating system, gene flow and hybridization in the genus Rhinanthus.
TECHNICAL ADVANCES: New strategies for telomere‐based age estimation
Authors: HAUSSMANN MARK F. , MAUCK ROBERT A.
Published: September 2007

Telomere dynamics link molecular and cellular mechanisms with organismal processes and therefore may explain variation in a number of important life‐history traits. Telomere length has been used to estimate age in free‐living populations of animals. Such estimation is a potentially powerful tool in the context of population dynamics and management, as well as the study of life‐history trade‐offs. The number of studies utilizing telomere restriction fragment assays in the fields of ecology and evolution is steadily growing. However, the field lacks methodological and analytical standardization resulting in considerable variation in telomere length and therefore in the usefulness of these techniques. Here, we illustrate new laboratory and analytical methods to reliably measure telomere length from blood erythrocytes and accurately assess the relationship between telomeres and age. We demonstrate the importance of analysing those telomeres most relevant to age‐related studies: the shortest telomeres. We present a reliable method to quickly identify an analysis window (the telomere optimal estimate, TOE) which approaches the optimal window for age estimation. Because the TOE focuses on the shortest telomeres — those telomeres which signal cellular senescence and ageing — TOE can also be used to compare telomeres in age‐matched individuals. We also compare constant‐ and pulsed‐field gel electrophoresis to show how each can influence telomere measurement. The use of TOE should provide powerful telomere‐based age estimation and enable organismal biologists to readily uncover individual and longitudinal differences with regard to telomere dynamics.
PERMANENT GENETIC RESOURCES: A set of primer pairs for amplifying the complete mitochondrial DNA of endangered Chinese egret (Aves, Ardeidae, Egretta eulophotes)
Authors: ZHOU XIAOPING , WANG YIQUAN , CHEN XIAOLIN , LIN QINGXIAN , FANG WENZHEN , WEI DONG
Published: September 2007

The Chinese egret is a globally endangered species. Here we describe a set of primer pairs to amplify its entire mtDNA. The polymerase chain reaction products (1000–2000 bp) were successfully amplified by using this primer set and were then sequenced and aligned. The contiguous mtDNA sequences of the Chinese egret were assembled to be a circular molecule (17 579 bp). This primer set was also confirmed to be useful for six other species of ardeid birds. The versatility of this primer set will provide a groundwork for further studies on the genetic structure and molecular evolution of the ardeid species.
PERMANENT GENETIC RESOURCES: Polymorphic microsatellite loci and interspecific cross‐amplification in the parasitoid wasps Megastigmus stigmatizans and Megastigmus dorsalis
Authors: GARNIER S. , VERDUIJN M. , PREUSS S. , WOLFF K. , STONE G. N.
Published: September 2007

We isolated and characterized 19 polymorphic microsatellite loci in the congeneric parasitoid wasps Megastigmus stigmatizans and Megastigmus dorsalis associated with cynipid oak galls. Loci isolated from species‐specific libraries showed extensive cross‐amplification, resulting in a total of 15 polymorphic loci for M. stigmatizans and 13 for M. dorsalis.
Neuroactive Properties of Reproductive Steroids
Authors: Herzog Andrew G.
Published: September 2007

Migraine is 3 times more common in postpubertal women than in men. Migraine is frequently exacerbated perimenstrually and commonly occurs exclusively at that time. It is often benefited by pregnancy and menopause. Estrogen withdrawal has been implicated as a mechanism for triggering migraines. The mechanism, however, is not well understood. Reproductive steroids have neuroactive properties that can modulate neuronal morphology and physiology. Increasing evidence suggests that circulating reproductive steroid levels regulate the balance of neuroexcitatory and neuroinhibitory activities in some brain regions by influencing synaptic plasticity. Estrogen has neuroexcitatory, whereas progesterone has neuroinhibitory, effects in most preclinical and clinical models. Several neurotransmitter systems that are implicated in migraine vary with reproductive steroid levels during the reproductive cycle. Estrogen stabilization may provide effective treatment in susceptible women, especially for catamenially exacerbated migraine.
Understanding the Causes and Prevention of Menstrual Migraine: The Role of Estrogen
Authors: Newman Lawrence C.
Published: September 2007

Menstruation increases the risk of migraine in susceptible women. In a subpopulation of women with menstrual migraine, headaches occurring in association with onset of menses may be more severe and of longer duration than headaches experienced by the same woman at other times of her menstrual cycle. Although menstrual migraines share many clinical characteristics of other types of migraines, their occurrence is predictable provided that the patient has regular menstrual cycles. Therefore, short‐term prevention regimens can be considered for women whose headaches are not adequately managed with acute therapies.
Migration of a Kirschner wire to the heart in a Yorkshire terrier
Authors: Crosara S. , Zabarino S. , Morello E. , Iussich S. , Buracco P. , Borgarelli M.
Published: September 2007

A 12‐year‐old, male Yorkshire terrier was presented for acute pulmonary oedema. Thoracic radiographs showed a linear metallic foreign body within the cardiac silhouette. Echocardiogram showed a hyperechoic line extending through the left ventricle, the mitral valve, leading into the left atrium. A 4 cm long Kirschner wire was surgically removed by left fourth thoracotomy. The dog died two days after surgery for acute pulmonary oedema. Necropsy showed thrombi on the mitral leaflets that impeded their movement.
A study of inherited short tail and taillessness in Pembroke Welsh corgi
Authors: Indrebø A. , Langeland M. , Juul H. M. , Skogmo H. K. , Rengmark A. H. , Lingaas F.
Published: September 2007

Objectives: To study whether natural short tail in adult Pembroke Welsh corgi is associated with congenital spinal defects. To report anatomical defects in two newborn tailless puppies from short‐tailed parents, and to check whether they were homozygous for the dominant mutation in the T‐gene (C295G).

Methods: The vertebral column of 19 adult dogs with natural short tail, from short‐tail×long‐tail crossings, was radiographically examined. Two tailless puppies were radiographed and submitted for necropsy. Samples from the puppies, their parents and five siblings were analysed for the mutation of the T‐gene.

Results: No congenital spinal defects were diagnosed in any of the short‐tailed dogs. The tailless puppies had anorectal atresia, had multiple spinal defects and were homozygous for the mutation in the T‐gene.

Clinical Significance: As tail docking is forbidden in many countries, breeding Pembroke Welsh corgis with natural short tail is becoming increasingly common. Previous studies indicated that the mutation in homozygotes is lethal in early fetal life. It is of clinical significance that natural short tail is probably not associated with congenital spinal defects, as is known from studies of other species, and that homozygotes for this mutation with serious anatomical defects may be born.
The use of magnetic resonance imaging in the management of pharyngeal penetration injuries in dogs
Authors: Dobromylskyj M. J. , Dennis R. , Ladlow J. F. , Adams V. J.
Published: September 2007

Objectives: To investigate the correlation between the magnetic resonance imaging findings and subsequent surgical findings for a series of dogs presenting with suspected pharyngeal stick injuries to the Animal Health Trust, Newmarket, between 1995 and 2004.

Methods: Magnetic resonance imaging findings were reviewed for patients undergoing a scan of the pharyngeal or cervical area for suspected foreign bodies during the years 1995 to 2004.

Results: Case signalment, history and clinical signs were similar to those reported in previous studies. Magnetic resonance imaging demonstrated foreign material in six of seven cases where this was present. There was good correlation between diagnosis of a foreign body at magnetic resonance imaging and subsequent surgical identification.

Clinical Significance: Compared with other imaging modalities, magnetic resonance imaging is very helpful for this type of injury, especially in chronic cases where radiographic evidence of a foreign body is unlikely. It is a valuable aid in the diagnosis of pharyngeal penetration injury and in surgical planning.
Antibiotic susceptibility of bacteria isolated from cats with ulcerative keratitis in Taiwan
Authors: Lin C.‐T. , Petersen‐Jones S. M.
Published: September 2007

Objectives:To assess the antibiotic susceptibility of bacteria isolated from corneal ulcers in cats.

Methods:A total of 92 cats with infected corneal ulcers were swabbed for bacterial culture and the antibiotic sensitivity of the isolates analysed.

Results:Bacteria were isolated from 54 of 92 infected eyes with corneal ulcers and purulent discharge. A total of 59 bacterial isolates were obtained from the 54 ulcers. The ratio of Gram‐positive to Gram‐negative isolates was approximately 3:1. The most commonly isolated Gram‐positive bacteria wereStaphylococcusspecies (51 per cent of all isolates), whilePseudomonas aeruginosa(13·5 per cent of all isolates) was the most common Gram‐negative bacteria isolated. The Gram‐negative isolates demonstrated a greater incidence of antibiotic resistance than the Gram‐positive ones. The most effective antibiotics against the isolates were ciprofloxacin, tobramycin and gentamicin, with erythromycin and lincomycin showing the greatest number of resistant isolates.

ClinicalSignificance:StaphylococcusandPseudomonasspecies were the most common Gram‐positive and Gram‐negative bacteria, respectively, isolated from feline eyes with ulcerative keratitis. The second‐generation fluoroquinolone, ciprofloxacin and the aminoglycoside gentamicin were found to be highly effective against the majority of isolates.
Methaemoglobinaemia caused by hydroxycarbamide (hydroxyurea) ingestion in a dog
Authors: Wray J. D.
Published: September 2007

A three‐year‐old female neutered greyhound was presented after ingestion of its owner’s hydroxycarbamide (hydroxyurea) tablets. The dog was found to be cyanosed, and methaemoglobinaemia was demonstrated by co‐oximetry. Therapy included methylene blue, oxygen, packed red blood cell transfusion, N‐acetylcysteine and crystalloid fluids. Methaemoglobinaemia resolved within 16 hours. Granulocyte colony‐stimulating factor was administered for five days in an attempt to prevent severe neutropenia. Mild delayed transient myelotoxicity was suspected. The dog made a full recovery.
Treatment of pancreatitis‐associated extrahepatic biliary tract obstruction by choledochal stenting in seven cats
Authors: Mayhew P. D. , Weisse C. W.
Published: September 2007

Objectives: To report the clinicopathological findings and outcome in cats with pancreatitis‐associated extrahepatic biliary tract obstruction (EHBO) treated by choledochal tube stenting.

Methods: Medical records of cats with EHBO secondary to pancreatitis that underwent choledochal stenting were reviewed. Information on outcome was obtained by re‐examination of the cat or by telephone interview with the owners.

Results: All cats had pancreatitis confirmed by histopathological examination of biopsy samples (n=6) or suspected based on gross examination at surgery (n=1). In six cats, a section of 3·5 to five French gauge red rubber catheter and in one cat a section of 22 G intravenous catheter were used as a choledochal stent. Two cats developed re‐obstruction of the biliary tract within a week of the original surgery. One cat had confirmed episodes of ascending cholangitis postoperatively. Two cats had chronic intermittent vomiting in the postoperative period. Two cats died during the perioperative period. Five cats survived to discharge, three of which died seven to 24 months postoperatively and two of which remain alive to date.

Clinical Significance: Choledochal stenting is an alternative to biliary diversion for management of feline pancreatitis‐associated EHBO in select cases. However, there may be greater morbidity with this technique in cats compared with dogs.