bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationships among fire frequency, rainfall and vegetation patterns in the wet–dry tropics of northern Australia: an analysis based on NOAA‐AVHRR data
Authors: Spessa Allan , McBeth Bevan , Prentice Colin
Published: August 2005

Aim  To quantify the regional‐scale spatio‐temporal relationships among rainfall, vegetation and fire frequency in the Australian wet–dry tropics (AWDT).

Location  Northern Australia: Cape York Peninsula, central Arnhem, central Kimberly, Einasleigh Uplands, Gulf Fall Uplands and northern Kimberley.

Methods  Monthly ‘fraction of photosynthetic active radiation absorbed by green vegetation’ (fAPAR) was decomposed into monthly evergreen (EG) and monthly raingreen (RG) components using time‐series techniques applied to monthly normalized difference vegetation index (NDVI) data from Advanced Very High Resolution Radiometer (AVHRR) imagery. Fire affected areas were independently mapped at the same spatio‐temporal resolution from AVHRR imagery. Weather station records were spatially interpolated to create monthly rainfall surfaces. Vegetation structural classes were derived from a digitized map of northern Australian vegetation communities (1 : 1,000,000). Generalized linear models were used to quantify relationships among the fAPAR, EG and RG signals, vegetation structure, rainfall and fire frequency, for the period November 1996–December 2001.

Results  The fAPAR and EG signals are positively correlated with annual rainfall and canopy cover, notably: EGclosed forest > EGopen heathland > EGopen forest > EGwoodland > EGopen woodland > EGlow woodland > EGlow open woodland > EGopen grassland. Vegetation height and fAPAR are positively correlated, excluding the special case of open heathland. The RG signal is highest where intermediate annual rainfall and strong seasonality in rainfall coincide, and is associated with vegetation structure as follows: RGopen grassland > RGwoodland > RGopen forest > RGopen heathland > RGlow woodland > RGopen woodland > RGlow open woodland > RGclosed forest. Monthly RG tracks monthly rainfall. Annual proportion of area burnt (PB) is maximal where high RG coincides with low EG (open grassland, several woodland communities). PB is minimal in vegetation where both RG and EG are low (low open woodland); and in vegetation where EG is high (closed forest, open heathland).

Conclusions  The RG–EG scheme successfully reflects digitally mapped tree and grass covers in relation to rainfall. RG–EG patterns are strongly associated with fire frequency patterns. PB is maximal in areas of high RG, where high biomass production during the wet season supports abundant fine fuel during the dry season. PB is minimal in areas with high EG, where relatively moist fuel limits fire ignition; and in areas with low EG and RG, where a relative short supply of fuel limits fire spread.
Mammalian beta diversity in the Great Basin, western USA: palaeontological data suggest deep origin of modern macroecological structure
Authors: Davis Edward Byrd
Published: August 2005

Aim  Recent work indicates that desert assemblages have elevated beta (β) diversity (between‐locality turnover of species composition). This study compares β diversities between the Great Basin and the Great Plains of the western USA over the last 17 Myr. Today, the Great Basin is a topographically diverse desert scrubland to woodland and the Great Plains are low‐relief temperate grassland, but 17 Ma they were more similar in topography, climate and land cover. A georeferenced database of mammal occurrences, complied from several sources, is used to test two hypotheses for the elevation of Great Basin β diversity: (1) that tectonic change of the topography has driven increased habitat packing in high‐ and low‐elevation habitats, and (2) that climatic cycling in the Pleistocene has driven faunas from neighbouring provinces to overlap in the region.

Location  The Great Basin of the USA, centred on Nevada, and the central Great Plains of the USA, centred on Nebraska.

Methods  Mammalian faunal lists compiled from published records and the records of many museums, available online, were partitioned into time‐slices ranging from the recent to 17 Myr old. Beta diversity was calculated for each time‐slice in two ways: multiplicative β diversity using first‐order jackknife richness, and additive beta diversity using Simpson's evenness.

Results  Beta diversity is elevated in Nevada relative to Nebraska today. Beta diversity has been higher in the Great Basin since the Pleistocene and possibly since the late Early Hemphillian (c. 7 Ma). Beta diversity in the Late Barstovian (c. 13.5 Ma) of the Great Plains was higher even than β diversity in the Great Basin of today.

Main conclusions  The elevated β diversity in the Hemphillian supports the tectonic change hypothesis. The patterns of β diversity in the Recent, Pleistocene and Hemphillian all suggest that local‐scale processes are important. The β diversity of the Late Barstovian Great Plains supports other studies indicating increased primary productivity or species packing.
Revisiting Fayol: Anticipating Contemporary Management
Authors: Parker Lee D. , Ritson Philip A.
Published: August 2005

This study argues that in classifying Fayol as a founding father of the Classical Management School, we have to some extent misrepresented this still important management theorist. The received Fayol portrayed in contemporary texts invariably emerges as a caricature of a much more insightful, complex, visionary and rounded management thinker. This study re‐examines Fayol's personal and career history, as well as the arguments presented in his original work, General and Industrial Management. It finds that he was a much more complex and multidimensional figure than his conventional stereotype today, and that his management theories embraced a wider spectrum of approaches and concepts than traditionally identified with the classical management school of thought. In marked contrast to his traditional portrayal, this study uncovers traces of ideas and concepts that anticipated aspects of the human relations movement, systems‐based contingency theory, the movement towards greater employee involvement in decision‐making and elements of knowledge management.
Performance Perceptions of Organizational Citizenship Behaviours at Work: a Bi‐Level Study among Managers and Employees
Authors: Turnipseed David L. , Rassuli Ali
Published: August 2005

Organizational citizenship behaviours (OCB) are ‘extra‐role’, work‐directed actions theorized to contribute to organizational effectiveness. However, the link between OCB and performance is not firmly based on empirical study. First, we argue that managers and employees may have different perceptions of OCB. The level of OCB will be perceived to be higher by managers than by employees. Second, we suggest that ‘best’ performing employees will have higher levels of OCB, and a stronger OCB–performance linkage than ‘worst’ performers. Using a sample of unionized workers and their managers, we investigated perceptions of OCB and the magnitude of OCB performance relationships from two hierarchical levels: managers and employees. ‘Best’ performing employees scored higher on OCB, and had a stronger OCB–performance linkage than the ‘worst’ performing group for helping‐type OCBs. Managers scored employees lower on OCB than employees scored their peers. In addition, managers perceived a stronger OCB–performance link than employee respondents. The results provide new and pragmatic implications of the OCB construct, including managerial clarification of ‘extra’ versus expected behaviours, review of job descriptions, moving valuable OCBs from ‘extra‐role’ to expected, and enhancing OCB by providing rewards. We suggest further causal studies to determine the specific contributions of various OCBs, identification and management of workplace antecedents of OCB, and determination of the reasons for the bi‐level differences in perceptions.
The Impact of Downsizing on Corporate Reputation
Authors: Zyglidopoulos Stelios C.
Published: August 2005

This study investigates the impact that downsizing has on corporate reputation. Drawing on the relevant literatures, two hypotheses are developed and tested. The findings of the study are as follows. First, downsizing has a negative impact on corporate reputation. Second downsizing is more damaging to corporate reputation than ‘downscoping’–the sale of a division.
Estimated Estimating Equations: Semiparametric Inference for Clustered and Longitudinal Data
Authors: Chiou Jeng-Min , Müller Hans-Georg
Published: August 2005

We introduce a flexible marginal modelling approach for statistical inference for clustered and longitudinal data under minimal assumptions. This estimated estimating equations approach is semiparametric and the proposed models are fitted by quasi-likelihood regression, where the unknown marginal means are a function of the fixed effects linear predictor with unknown smooth link, and variance–covariance is an unknown smooth function of the marginal means. We propose to estimate the nonparametric link and variance–covariance functions via smoothing methods, whereas the regression parameters are obtained via the estimated estimating equations. These are score equations that contain nonparametric function estimates. The proposed estimated estimating equations approach is motivated by its flexibility and easy implementation. Moreover, if data follow a generalized linear mixed model, with either a specified or an unspecified distribution of random effects and link function, the model proposed emerges as the corresponding marginal (population-average) version and can be used to obtain inference for the fixed effects in the underlying generalized linear mixed model, without the need to specify any other components of this generalized linear mixed model. Among marginal models, the estimated estimating equations approach provides a flexible alternative to modelling with generalized estimating equations. Applications of estimated estimating equations include diagnostics and link selection. The asymptotic distribution of the proposed estimators for the model parameters is derived, enabling statistical inference. Practical illustrations include Poisson modelling of repeated epileptic seizure counts and simulations for clustered binomial responses.
Modelling Directional Dispersion through Hyperspherical Log-Splines
Authors: Ferreira José T. A. S. , Steel Mark F. J.
Published: August 2005

We introduce the directionally dispersed class of multivariate distributions, a generalization of the elliptical class. By allowing dispersion of multivariate random variables to vary with direction it is possible to generate a very wide and flexible class of distributions. Directionally dispersed distributions have a simple form for their density, which extends a spherically symmetric density function by including a function D modelling directional dispersion. Under a mild condition, the class of distributions is shown to preserve both unimodality and moment existence. By adequately defining D, it is possible to generate skewed distributions. Using spline models on hyperspheres, we suggest a very flexible, yet practical, implementation for modelling directional dispersion in any dimension. Finally, we use the new class of distributions in a Bayesian regression set-up and analyse the distributions of a set of biomedical measurements and a sample of US manufacturing firms.
Where Did the Bureaucrats Go? Role and Influence of the Public Bureaucracy in the Swedish and French Pension Reform Debate
Authors: MARIER PATRIK
Published: August 2005

This article has two key objectives. First, despite having been considered as a key element to favor the expansion and elaboration of the welfare state in industrial countries, bureaucrats have been largely ignored by the “New” Politics of the Welfare State. This article demonstrates that bureaucrats still matter in times of retrenchment, because they can facilitate or obstruct various phases of the policy process. The degree of independence of the bureaucracy vis‐à‐vis the government, the government's level of dependency  and  trust  on  public  expertise, the locus of ministerial power, and political deadlocks contribute to either accentuate or decrease the influence of the bureaucracy in the retrenchment of social policies. Second, these elements are analyzed via a comparison of the pension reform processes in France and Sweden. This article argues that the French bureaucracy, despite its high degree of centralization and powers, has been far less successful than its Swedish counterpart. The Swedish institutional structure, the predominance of social ministries in pension affairs, and the trust given to an independent agency account for this puzzling outcome.
Civil Servants, Economic Ideas, and Economic Policies: Lessons from Italy
Authors: QUAGLIA LUCIA
Published: August 2005

Building on theoretically oriented and empirically grounded research on two key macroeconomic institutions in Italy, this article explains how and why civil servants can engineer major policy changes, making a difference in a country's trajectory. Italy provides a challenging testing ground for this kind of analysis, as it is generally portrayed as a highly politicized system in which political parties and politicians fully control public policies. Three general lessons can be learned, the first being that the role of civil servants in changing modes of economic governance depends on the resources that they master in the system in which they operate. “Intangible assets” are of primary importance in complex and perceived technical policies, such as monetary and exchange rate policy, which have high potential for “technocratic capture.” Second, in these policies, certain intangible assets, such as specific bodies of economic knowledge or policy paradigms, have a considerable impact on policy making. Third, besides interactions in international fora, the professional training of civil servants is a mainstream way through which economic policy beliefs circulate and gain currency, laying the foundations for policy shifts. By highlighting the importance of the intangible assets of macroeconomic institutions, this research makes an unorthodox contribution to the primarily economic literature on central bank independence.
Coordinating the Government Bureaucracy in Hong Kong: An Institutional Analysis
Authors: LAM WAI FUNG
Published: August 2005

The change in sovereignty of Hong Kong in 1997 has brought about an interesting puzzle: despite a high degree of institutional continuity, the Hong Kong bureaucracy that was considered highly efficient during the colonial era has appeared to turn into an inept administrative structure generating blunder after blunder. The bureaucracy seems to face greater difficulties in horizontal coordination under the new governance, and has lost the ability to produce coherent policy actions.

Drawing upon a literature of institutional analysis, this article examines the institutional design for coordination in the Hong Kong government. The article argues that the bureaucracy in Hong Kong is designed upon a logic of colonial rule. Like any institutional arrangements, the colonial administrative system has inherent coordination limitations. During the colonial era, some smoothing mechanisms were developed as the lubricant for the bureaucracy's operation, but the new governance has inevitably impinged upon some of these—making the bureaucracy more prone to coordination problems.
The Recasting of Insolvency Law
Authors: Finch Vanessa
Published: August 2005

Over the last decade corporate insolvency laws and processes have changed in two important ways. There has been a philosophical shift away from ex post responses to corporate crises and towards influencing the way that corporate actors manage the risks of insolvency ex ante. In addition, there has been a revision of insolvency roles so that participants in corporate and insolvency processes are increasingly encouraged to see corporate decline as a matter to be anticipated and prevented rather than responded to after the event. In this development turnaround specialists have gained a new prominence. These are changes that reflect broader social and governmental trends to audit performance more actively and to see issues in terms of needs to manage risks. Such developments are important for corporate and insolvency lawyers – they recast a host of issues within new framing assumptions and they force a re‐thinking of corporate insolvency law's challenges and agendas.
Developmental trajectories of conduct problems and hyperactivity from ages 2 to 10
Authors: Shaw Daniel S. , Lacourse Eric , Nagin Daniel S.
Published: August 2005

Background:  Conduct problems (CP) and hyperactivity/attention problems (HAP) are thought to covary with regularity, yet few studies have examined their co‐occurrence or risk factors that discriminate their trajectories beginning in early childhood.

Method:  The present study sought to advance our understanding of this issue by examining separate trajectories of overt CP and HAP symptomatology among 284 boys from urban, low‐income families followed from ages 1.5 to 10. We also investigated the co‐occurrence of persistent CP and HAP and explored risk factors that discriminate CP and HAP trajectories.

Results:  Four similar trajectory groups were identified for both CP and HAP symptoms. Chronic CP was differentiated from persistent low CP by risk factors in child, parenting, and family domains, while chronic trajectories of HAP were typified by elevated maternal depressive symptoms compared to children with persistent low HAP.

Conclusions:  The findings extend previous research with older children of HAP and/or CP, highlighting the effects of proximal family and child risk factors that are identifiable in the first two years of children's lives and associated with trajectories of disruptive behavior.
Dynamic process of family burden in dementia caregiving: a new field for psychotherapeutic interventions
Authors: MICHON Agnès , WEBER Kerstin , RUDHARD‐THOMAZIC Valérie , GIANNAKOPOULOS Panteleimon
Published: August 2005

Families caring for a patient with dementia are prone to significant physical, psychological and social stress. It is now well established that the caregiver burden does not only negatively affect the caregiver's physical and mental health, but is also associated with an increase in behavioural and psychiatric symptoms of dementia. Burden determinants include the quality of the relationship between the patient and caregiver; patient variables, such as the need to manage the behavioural and psychological symptoms of dementia; and also caregiver variables, such as the satisfaction of caring, demographic characteristics and societal roles. The standardised assessment of interventions for caregivers in dementia care remains a difficult task. In recent years, family interventions that focus on the process of burden itself in relation to the caregiver's subjective experience of personal growth and enrichment have been proposed. This new approach is based on the identification of tasks and challenges faced by family members throughout the different stages of the disease. In this context, brief crisis interventions transform periods of disorganisation experienced by the family into opportunities for change, whereas rehabilitation interventions developed by professional caring networks offer a continuous assessment and advice to the family. This article provides a critical review of the consequences and determinants of caregiver burden in dementia care with special reference to the emerging notion of the caregiver's subjective experience in the context of family processes.
Evaluation of a computerized test system to screen for mild cognitive impairment
Authors: INOUE Masashi , URAKAMI Katsuya , TANIGUCHI Miyako , KIMURA Yuki , SAITO Jun , NAKASHIMA Kenji
Published: August 2005

Background:  Mild cognitive impairment (MCI) refers to the clinical condition between normal aging and Alzheimer's disease (AD) and has a high probability of developing into AD. Early detection of MCI is important because early detection and appropriate follow‐up treatment can prevent the disease from progressing. Therefore, MCI is an important candidate for screening and possible intervention.

Methods:  We have developed a computerized screening test system to identify cognitive decline. This system consists of six tests (age and year‐of‐birth validity test, three‐word memory test, time orientation test, first modified delayed‐recall test, visual working memory test and second modified delayed‐recall test). The scores obtained from three groups (MCI patients, AD patients and healthy control subjects) were analyzed to evaluate the sensitivity and specificity required for the screening of MCI.

Results:  The system was well accepted by the patients. All of the test procedures were completed within 5 min. Significant group differences in all test results were found. The system has sensitivity and specificity values of 82% and 87%, respectively, when used as a screen for MCI.

Conclusion:  The system is useful for the screening of cognitive disorders.
Relation between schizophrenia and Alzheimer's disease: the reelin signaling pathway
Authors: AOKI Takeya , MIZUKI Yasushi , TERASHIMA Toshio
Published: August 2005

Reelin is an extracellular matrix protein that is related to neuronal migration at the embryonic stage. Recently, the relation between reelin and schizophrenia and Alzheimer's disease was established. The authors summarize these two disorders from the perspective of the reelin signaling pathway. Reelin and reelin mRNA are reduced in the schizophrenic brain and Cajal–Retzius cells, which secrete reelin, are reduced in the Alzheimer's brain. From the reelin signaling pathway, a reduction or deficit of reelin leads to the disturbance of neuronal migration and abnormal phosphorylation of tau protein, and may be a pathologic factor involved in the etiology of schizophrenia and Alzheimer's disease. Reelin may be the common feature of both schizophrenia and Alzheimer's disease.
Uses of Agent‐Based Modeling in Innovation/New Product Development Research*
Authors: Garcia Rosanna
Published: August 2005

Little has been written in the new product development literature about the simulation technique agent‐based modeling, which is a by‐product of recent explorations into complex adaptive systems in other disciplines. Agent‐based models (ABM) are commonly used in other social sciences to represent individual actors (or groups) in a dynamic adaptive system. The social system may be a marketplace, an organization, or any type of system that acts as a collective of individuals. Agents represent autonomous decision‐making entities that interact with each other and/or with their environment based on a set of rules. These rules dictate the behavioral choices of the agents. In these simulation models, heterogeneous agents interact with each other in a repetitive process. It is from the interactions between agents that aggregate macroscale behaviors or trends emerge. The simulated environment can be thought of as a “virtual” society in which actions taken by one agent may have an effect on the resulting actions of another agent.

This article is an introduction to the ABM methodology and its possible uses for innovation and new product development researchers. It explores the benefits and issues with modeling dynamic systems using this methodology. Benefits of ABMs found in sociology and management studies have found that as the heterogeneity of individuals increase in a system or as network effects become more important in a system, the effectiveness of ABMs as a methodology increases. Additionally, the more adaptive a system or the more the system evolves over time, the greater the opportunity to learn more about the adaptive system using ABMs. Limitations to using this methodology include some knowledge of computer‐programming techniques.

Three potential areas of research are introduced: diffusion of innovations, organizational strategy, and knowledge and information flows. A common use of ABMs in the extant literature has been the modeling of the diffusion process between networked heterogeneous agents. ABMs easily allow the modeling of different types of networks and the impact of these networks on the diffusion process. A demonstrative example of an agent‐based model to address the research question of how should manufacturers allocate resources to research (exploration) and development (exploitation) projects is provided. Future courses of study using ABMs also are explored.
New Product Development Performance and the Interaction of Cross‐Functional Integration and Knowledge Management
Authors: Daniel Sherman J. , Berkowitz David , Souder William E.
Published: August 2005

Previous research on cross‐functional integration between research and development (R&D) and marketing has focused on the development of appropriate structural modes and levels of integration and cooperation across the R&D–marketing interface. A gap in the previous research in this area has been the failure to investigate the integration of information from past related product development projects (i.e., knowledge management). In this investigation of R&D–marketing integration, variables from the emerging research literature on organizational learning and knowledge management are examined. By simultaneously investigating the effects of knowledge management variables and R&D–marketing integration, this gap in the literature is addressed. The results demonstrate that the combined effects of R&D–marketing integration and knowledge management in the form of recording, retrieving, and reviewing information from past projects results in interaction effects. In 8 of 18 tests interactions were found. In 6 of 18 tests these resulted in the form of amplification effects with dependent variables such as product prototype development proficiency, product launch proficiency, technological core competency fit, and design change frequency.
The Growing Contributions of Molecular Biology and Immunology to Protistan Ecology: Molecular Signatures as Ecological Tools1
Authors: CARON DAVID A. , COUNTWAY PETER D. , BROWN MARK V.
Published: August 2005

ABSTRACT. Modern genetic and immunological techniques have become important tools for assessing protistan species diversity for both the identification and quantification of specific taxa in natural microbial communities. Although these methods are still gaining use among ecologists, the new approaches have already had a significant impact on our understanding of protistan diversity and biogeography. For example, genetic studies of environmental samples have uncovered many protistan phylotypes that do not match the DNA sequences of any cultured organisms, and whose morphological identities are unknown at the present time. Additionally, rapid and sensitive methods for detecting and enumerating taxa of special importance (e.g. bloom‐forming algae, parasitic protists) have enabled much more detailed distributional and experimental studies than have been possible using traditional methods. Nevertheless, while the application of molecular approaches has advanced some aspects of aquatic protistan ecology, significant issues still thwart the widespread adoption of these approaches. These issues include the highly technical nature of some of the molecular methods, the reconciliation of morphology‐based and sequence‐based species identifications, and the species concept itself.
A Multidisciplinary Approach to Describe Protists: a Morphological, Ultrastructural, and Molecular Study on Peritromus kahliVilleneuve‐Brachon, 1940 (Ciliophora, Heterotrichea)
Authors: ROSATI GIOVANNA , MODEO LETIZIA , MELAI MICHELE , PETRONI GIULIO , VERNI FRANCO
Published: August 2005

ABSTRACT. This study represents the first extended report on a species of the ciliathd genus Peritromus, widespread in marine biotopes, characterized by a dorso‐ventral differentiation peculiar among Heterotrichea. Morphological observations (live, stained, scanning, and transmission electron microscope) were combined with behavioral and molecular data. On the basis of the whole body of observations, the species was recognized as Peritromus kahli. Scanning and transmission electron microscopy have revealed a number of features such as peculiar chalice‐like structures external to the dorsal surface, two types of extrusomes, and differences between dorsal and ventral somatic ciliature. The almost complete SSrDNA gene sequence was also determined. A molecular phylogenetic analysis indicated that Peritromus diverged early from other members of the Class Heterotrichea. The dorso‐ventral differentiation that certainly influences the behavior of P. kahli (e.g. preference for crawling and thigmotaxis) may have been selected as an adaptation to the constraints of the interstitial habitat.
Evidence for Adhesive Activity of the Ventrolateral Flange in Giardia lamblia
Authors: ERLANDSEN STANLEY L. , RUSSO A. PETER , TURNER JAMES N.
Published: August 2005

ABSTRACT. Giardia lamblia is an intestinal protozoan that inhabits the intestinal tract of man and other mammals by attaching to the mucosal surface via the contractile activity of an attachment organelle called the ventral adhesive disk. We have investigated the presence of other attachment mechanisms in G. lamblia trophozoites by using microfabricated substrates that sterically interfere with formation of the hypothesized “negative pressure” under the ventral adhesive disk that would mediate attachment to a substratum. Pillars measuring 1 μm high and 2 μm in diam. were constructed in microarrays with spacings smaller than the diameter of the ventral adhesive disk. Using high resolution field emission scanning electron microscopy, the attachment of trophozoites to the tops of pillars in the microfabricated substrates was investigated. Firm adhesion of trophozoites was observed to be mediated by direct attachment of the ventrolateral flange membrane to the tops of microfabricated pillars. Attachment to microfabricated surfaces was 16% of that observed for attachment mediated by the ventral adhesive disk (4.4 ± 1.5 cells/100 μ2 micropillar surface vs. 25.9 ± 3.1 cells/100 μ2 flat substrate, p < 0.0001) This is the first report of trophozoite adhesion to a substratum by a mechanism other than the direct attachment of the ventral adhesive disk, and provides experimental evidence that the ventrolateral flange may play a role in trophozoite adhesion. A hypothesis is presented describing how the adhesive nature of the ventrolateral flange might be involved in normal attachment of G. lamblia trophozoites to a substratum.
Injection‐Molded Alumina Prepared with Mg‐Containing Binders
Authors: Hwang K. S. , Hsieh C. C.
Published: August 2005

It is generally accepted that MgO additions enhance the sintering of alumina. The distribution of the low concentration required is, however, difficult to attain and critical to the final properties and microstructures. To improve the MgO distributions in ceramic injection‐molded (CIM) alumina, Mg‐containing precursors, Mg‐stearate and Mg‐acetate, were added during the kneading step of the CIM process, and the results were compared with those from adding MgO particles. Of the three additives, the Mg‐stearate showed the highest sintered density and bending strength. This was attributed to its high molecular weight and it being able to mix with other binder components homogeneously in the liquid state, which leads to a better distribution of the MgO. In contrast, the MgO powder was kneaded in the solid particle form, and its distribution was not uniform. The Mg‐acetate also imparted poorer MgO distribution because the liquid Mg‐acetate dehydrated in the early stage of the kneading and formed solid lumps before it was well mixed into the binder system. The resulting sintered densities and bending strength using these two additives were, therefore, inferior to those for specimens in which Mg‐stearate was used.
Fatigue Crack Growth for BaTiO3 Ferroelectric Single Crystals Under Cyclic Electric Loading
Authors: Fang F. , Yang W. , Zhang F. C. , Luo H. S.
Published: August 2005

Electrically induced fatigue crack growth is an important degradation mechanism for ferroelectric devices. Reliability concerns for ferroelectric devices place stringent demands for ferroelectric materials. In situ observation of electrically induced fatigue crack growth was carried out for ferroelectric single crystals under alternating electric field. Electrically induced fatigue crack growth was observed both below and above the coercive field. Crack closure and open behavior were observed together with 90° ferroelectric domain switching during the electric cycling. The crack propagation behavior is a repeated process of continuous but small increments followed by a sudden increase in the crack length. It was suggested that the electric boundary condition along the crack face, from its mouth to its tip, is a variation from the impermeable to the permeable state. The gradual attainment of an impermeable crack tip after an incubation period of field cycling causes the observed jump in crack propagation.
The Bi2O3–Nb2O5–NiO Phase Diagram
Authors: Valant Matjaz , Suvorov Danilo
Published: August 2005

The Bi2O3–Nb2O5–NiO phase diagram at 1100°C was determined by means of solid‐state synthesis, X‐ray diffraction, and scanning electron microscopy. A ternary eutectic with a melting point below 1100°C was found to exist in the field between NiO, Bi2O3, and the end‐member of the δBi2O3–Nb2O5 solid solution. The existence of the previously reported Bi3Ni2NbO9 phase was disproved. A pyrochlore homogeneity range around Bi1.5Ni0.67Nb1.33O6.25 was determined together with all the phase relations in this phase diagram.
Phase Equilibria and Thermodynamics in the Al2O3–SiO2 System—Modeling of Mullite and Liquid
Authors: Mao Huahai , Selleby Malin , Sundman Bo
Published: August 2005

The Al2O3–SiO2 system has been reassessed using a solution model for mullite extending from sillimanite to a hypothetical state of alumina. The property of sillimanite, to be used to describe one of the end‐members, was extracted from an analysis of the T–P phase diagram for Al2SiO5 polymorphs. It was possible to represent the information on the range of stability of mullite, including some showing that mullite extends to higher SiO2 contents than represented by the composition of 3:2 mullite. An attempt was made to model the liquid with the ionic two‐sublattice model using a new species AlO2−1. The pressure dependence of Al2SiO5 polymorphs was optimized by a new model recently implemented in Thermo‐Calc.
Porous Silicon Nitride Ceramics Prepared by Reduction–Nitridation of Silica
Authors: Shan Shao‐Yun , Yang Jian‐Feng , Gao Ji‐Qiang , Zhang Wen‐Hui , Jin Zhi‐Hao , Janssen Rolf , Ohji Tatsuki
Published: August 2005

A new method for preparing porous silicon nitride ceramics with high porosity had been developed by carbothermal reduction of die‐pressed green bodies composed of silicon dioxide, carbon, sintering additives, and seeds. The resultant porous silicon nitride ceramics showed fine microstructure and uniform pore structure. The influence of SiO2 particle size and sintering process (sintering temperature and retaining time) on the microstructure of sintering bodies was analyzed. X‐ray diffractometry demonstrated the formation of single‐phase β‐Si3N4 via the reaction between silicon dioxide and carbon at high temperature. SEM analysis showed that pores were formed by the banding up of rod‐like β‐Si3N4 grains. Porous Si3N4 ceramics with a porosity of 70–75%, and a strength of 5–8 MPa, were obtained.
A Novel Process for Low‐Density Alumina Foams
Authors: Prabhakaran Kuttan , Gokhale Nitin Madhusudan , Sharma Suresh Chandra , Lal Ramji
Published: August 2005

A novel process for low‐density alumina foams has been studied. Aqueous acidic sucrose solution containing aluminum nitrate when concentrated by heating formed a viscous resin. The resin mixed well with aqueous alumina slurry and the resulting powder‐filled resin underwent foaming on heating in a Teflon mold. The green foams produced had very good handling strength. Binder removal and sintering of the green foam prepared at sucrose to alumina weight ratio in the range 0.69–1.03 produced alumina foam bodies with porosities 93.5%–96.7%. Microstructure of the foams depends on sucrose to alumina weight ratio such that a clear transition from reticulated structure to cellular foam structure took place at sucrose to alumina weight ratio below 0.89. Average pore size depends on sucrose to alumina weight ratio and was observed in the range 0.48–2.69 mm.
Scandium‐Doped Anatase (TiO2) Nanoparticles Directly Formed by Hydrothermal Crystallization
Authors: Hirano Masanori , Date Kazuhiro
Published: August 2005

Anatase‐type TiO2solid solutions doped with 0–10 mol% scandium were formed by hydrothermal crystallization under weak basic conditions above 180°C for 5 h from amorphous co‐precipitates that were obtained from the aqueous precursor solutions of TiOSO4and Sc(NO3)3using aqueous ammonia. The anatase particles were spindle‐like and consisted of nanosized‐crystallites (23–25 nm). The lattice parameterc0of anatase and the length and width of the spindle‐like anatase gradually increased when the scandium content was increased. The diffuse reflectance spectra of the as‐prepared TiO2doped with scandium showed that the onset of absorption slightly shifted to longer wavelengths with increasing scandium content. The band gap of anatase was slightly increased by making solid solutions with scandium oxide.
Characterization and Microwave Dielectric Properties of M2+Nb2O6 Ceramics
Authors: Pullar Robert C. , Breeze Jonathan D. , Alford Neil McN.
Published: August 2005

This paper details the investigation of the quality factor (Q), dielectric permittivity (ɛr) and temperature coefficient of resonant frequency (τf) of the TE01δ mode of the columbite binary niobate ceramics, with the formula MNb2O6 where M=2+ cation, in relation to their degree of sintering, microstructure and phase composition. The ceramics were made from a mixed oxide preparative route and fired over a range of temperatures from 800° to 1400°C, and most formed the columbite structure. A comprehensive study was made of the niobates containing the transition metal cations M=Mn2+, Co2+, Ni2+, Cu2+, and Zn2+, and the group II metal cations M=Mg2+, Ca2+, Sr2+, and Ba2+. All columbite niobates were found to have ɛr between 17 and 22 and negative τf values between –45 and –76 ppm/°C, and ZnNb2O6, MgNb2O6, CaNb2O6, and CoNb2O6 had high Qf values of 84 500, 79 600, 49 600, and 41 700 GHz, respectively. The Qf of MgNb2O6 was found to rise to over 95 000 GHz when heated at 1300°C for 50 h.
A Low‐Temperature Molten Salt Synthesis of LiNiVO4 Cathode Material for Lithium Ion Batteries
Authors: Zhao Zhongqiang , Ma Junfeng , Xie Lijin , Tian Hua , Zhou Jun , Hu Yingmo , Huang Xiang , Wu Pingwei , Dai Jinhui , Zhu Zhibin , Wang Hongfen , Chen Haiyan
Published: August 2005

A newly developed molten salt method was applied at a temperature as low as 350°C to successfully synthesize an inverse spinel LiNiVO4 cathode by reacting lithium nitrate, nickel nitrate, and ammonium vanadate. As shown in XRD and TEM, the resultant product was a pure phase of LiNiVO4 without any other impurities. The powders showed a narrow particle size distribution with an average particle size of about 80 nm. No organic materials were introduced in the whole process.
Oxidation Resistance and High‐Temperature Lubricating Properties of Magnesium‐Phosphate‐Treated Graphite
Authors: Kita Hideki , Fukushima Manabu , Jayaseelan D. Doni , Zeng Yu‐Ping , Ohsumi Kazuo
Published: August 2005

The oxidation resistance and lubricating properties of graphite treated with magnesium phosphate were investigated. Magnesium‐phosphate‐treated graphite showed improved oxidation resistance. That is, with magnesium‐phosphate treatment, the oxidation temperature of graphite increased by almost 200°C. Furthermore, the friction coefficient of magnesium‐phosphate‐treated graphite measured at 500°C was about 0.05, which was smaller than that measured at room temperature.
Fabrication and Characterization of High‐Conductivity Bilayer Electrolytes for Intermediate‐Temperature Solid Oxide Fuel Cells
Authors: Park Jun‐Young , Yoon Heesung , Wachsman Eric D.
Published: August 2005

A stable bilayer electrolyte with high ionic conductivity was developed for intermediate‐temperature solid oxide fuel cell operation. The bilayer structure improved the limited thermodynamic stability of bismuth oxides and prevented electronic conductivity of ceria‐based oxides in reducing atmosphere. Bilayer electrolytes were formed by depositing thin and thick layers of erbia‐stabilized bismuth oxide (ESB) on samaria‐doped ceria (SDC) substrates, via pulsed laser deposition and dip‐coating techniques. Scanning electron microscope (SEM) images of the ESB/SDC samples showed dense ESB layers and excellent adherence between both ESB and SDC phases. Interdiffusion between the two phases was not detected by X‐ray diffraction and EDX. Measurements of the conductivity of SDC coated with ESB exhibited slightly higher total conductance than SDC.
Apatite Induction on Ca‐Containing Titania Formed by Micro‐Arc Oxidation
Authors: Song Won‐Hoon , Ryu Hyun Sam , Hong Seong‐Hyeon
Published: August 2005

Ca‐containing, particularly CaTiO3, titania films were prepared by micro‐arc oxidation (MAO) of Ti in an electrolytic solution containing calcium acetate monohydrate (CA), and their apatite‐inducing ability was evaluated in a simulated body fluid (SBF). The phase, Ca content, and morphology of the films were found to be strongly dependent on the applied voltage. The CaTiO3‐embedded titania was obtained at higher voltages (>300 V). When immersed in SBF, no apatite was induced in all the MAO specimens irrespective of the presence of CaTiO3, which has been claimed to be an apatite inducer. However, after a hydrothermal treatment at 250°C, apatite was formed on the surfaces of the CaTiO3‐embedded titania after 28 days, which was closely related to the formation of amorphous Ca(OH)2 and presumably surface Ti–OH groups.
Subsolidus Phase Relationships in the Ga2O3–Al2O3–TiO2 System
Authors: Jaromin Andrea L. , Edwards Doreen D.
Published: August 2005

Subsolidus phase relationships in the Ga2O3–Al2O3–TiO2 system at 1400°C were studied using X‐ray diffraction. Phases present in the pseudoternary system include TiO2 (rutile), Ga2−2xAl2xO3 (x≤0.78 β‐gallia structure), Al2−2yGa2yO3 (y≤0.12 corundum structure), Ga2−2xAl2xTiO5 (0≤x≤1 pseudobrookite structure), and several β‐gallia rutile intergrowths that can be expressed as Ga4−4xAl4xTin−4O2n−2 (x≤0.3, 15≤n≤33). This study showed no evidence to confirm that aluminum substitution of gallium stabilizes the n=7 β‐gallia–rutile intergrowth as has been mentioned in previous work.
Effects of CuO Content on the Wetting Behavior and Mechanical Properties of a Ag–CuO Braze for Ceramic Joining
Authors: Kim Jin Yong , Hardy John S. , Scott Weil K.
Published: August 2005

A silver‐based joining technique referred to as reactive air brazing has been recently developed for joining high‐temperature structural ceramic components of the type used in gas turbines, combustion engines, heat exchangers, and burners. It was found that additions of copper oxide to silver exhibit a tremendous effect on both the wettability and joint strength characteristics of the subsequent braze relative to polycrystalline alumina substrates. The effect is particularly significant at low copper oxide content, with substantial improvements in wetting observed in the 1–8 mol% range. The corresponding strength of the brazed polycrystalline alumina joints appears to be maximized at a copper oxide content of 8 mol%, with a maximum room temperature flexural strength approaching that of monolithic alumina. While further increases in oxide content lead to improved wetting on polycrystalline alumina, the effect on joint strength is deleterious. It appears that the formation of a continuous brittle copper‐based oxide layer along the interface between the braze and alumina faying surface is responsible for the poor mechanical behavior observed in joints fabricated with higher copper oxide content brazes.
Key Factors Controlling Camber Behavior During the Cofiring of Bi‐Layer Ceramic Dielectric Laminates
Authors: Hsu Rung‐Tsung , Jean Jau‐Ho
Published: August 2005

A bi‐layer low‐temperature‐cofired ceramic laminate with different dielectric constants has been used to investigate the key factors controlling camber behavior during cofiring. Camber development, which is caused by the linear shrinkage rate difference between dielectrics, becomes more significant with decreasing thickness of dielectric. No cofiring defects, such as de‐densification, de‐bonding, and channel cracks, are observed in the multilayer structure of mixed dielectric laminates. This is because of the fact that a common sintering flux is used in both dielectrics, and the sintering mismatch stress generated in the dielectric layer is less than that of sintering potential.
HEROShapers®: the adapted pitch concept
Authors: Calas Paul
Published: August 2005

The adapted pitch concept involves varying the pitch and the length of the cutting portion as a function of the taper of the instruments. By modifying these parameters, it is possible to select the instrument with the strength, efficacy, flexibility, and taper best suited for the root canal being prepared.

In the HEROShaper® sequence, instruments with a 0.06 taper are used to prepare and enlarge the coronal and middle thirds of the canal. These instruments have a longer pitch for enhanced flexibility and dentine cutting efficacy. The removal of dentinal chips is facilitated and the tendency to screw in is reduced. Instruments with a 0.04 taper are used to prepare the apical portion because they have a shorter pitch and cutting portion (12 mm), which makes them stronger and more flexible. They can thus negotiate apical curvatures without deviating from the initial canal axis.

The files are used in a continuous rotation mode (450–600 r.p.m.) to progressively prepare the root canal (crown‐down). The sequences are selected based on the difficulty of the original canal shape.
The K3 rotary nickel titanium instrument system
Authors: Gianluca Gambarini
Published: August 2005

K3 nickel–titanium rotary instruments were introduced to allow efficient and safe root canal preparation, due to their innovative design, with few if any limitations. Instruments can be moved smoothly down with the canal without threading themselves into it, cut well and resist to torsional and cyclic fatigue. The wide range of sizes allows different operative sequences, according to practitioners' choice. Guidelines for instrumentation and clinical hints are provided to maximize efficiency and safety.
FlexMaster: a universal system
Authors: Sonntag David
Published: August 2005

FlexMaster® NiTi files have been in successful application for some years, not only in Germany but also worldwide, and their use is becoming increasingly widespread. The cutting blade design of K‐type files provides for efficient working and effective removal of dentinal debris. Due to their convex cross‐sectional profile, these instruments are moreover equipped with a more solid instrument core which reduces the risk of fractures and deformations. FlexMaster® instruments are among the most comprehensively investigated rotary NiTi instruments. Very good results have been reported both in numerous in vitro studies and in an in vivo setting. The present article elucidates and assesses both the scientific setting and the clinical aspects of the system.