bluuebunny/crossref_metadata_2025_split huggingface dataset:
The RootChip: An Integrated Microfluidic Chip for Plant Science
Authors: Grossmann Guido , Guo Woei-Jiun , Ehrhardt David W. , Frommer Wolf B. , Sit Rene V. , Quake Stephen R. , Meier Matthias 
Published: December 2011

Abstract
Studying development and physiology of growing roots is challenging due to limitations regarding cellular and subcellular analysis under controlled environmental conditions. We describe a microfluidic chip platform, called RootChip, that integrates live-cell imaging of growth and metabolism of Arabidopsis thaliana roots with rapid modulation of environmental conditions. The RootChip has separate chambers for individual regulation of the microenvironment of multiple roots from multiple seedlings in parallel. We demonstrate the utility of The RootChip by monitoring time-resolved growth and cytosolic sugar levels at subcellular resolution in plants by a genetically encoded fluorescence sensor for glucose and galactose. The RootChip can be modified for use with roots from other plant species by adapting the chamber geometry and facilitates the systematic analysis of root growth and metabolism from multiple seedlings, paving the way for large-scale phenotyping of root metabolism and signaling.
Different Gene Families inArabidopsis thalianaTransposed in Different Epochs and at Different Frequencies throughout the Rosids
Authors: Woodhouse Margaret R. , Tang Haibao , Freeling Michael 
Published: December 2011

AbstractCertain types of gene families, such as those encoding most families of transcription factors, maintain their chromosomal syntenic positions throughout angiosperm evolutionary time. Other nonsyntenic gene families are prone to deletion, tandem duplication, and transposition. Here, we describe the chromosomal positional history of all genes in Arabidopsis thaliana throughout the rosid superorder. We introduce a public database where researchers can look up the positional history of their favorite A. thaliana gene or gene family. Finally, we show that specific gene families transposed at specific points in evolutionary time, particularly after whole-genome duplication events in the Brassicales, and suggest that genes in mobile gene families are under different selection pressure than syntenic genes.
Convergence acceleration in the polarization method for nonlinear periodic fields
Authors: Ciric Ioan R. , Hantila Florea I. , Maricaru Mihai 
Published: December 2011

PurposeThe purpose of this paper is to present three novel techniques aimed at increasing the efficiency of the polarization fixed point method for the solution of nonlinear periodic field problems.Design/methodology/approachFirstly, the characteristic B‐M resulting from the constitutive relation B‐H is replaced by a relation between the components of the harmonics of the vectors B and M. Secondly, a dynamic overrelaxation method is implemented for the convergence acceleration of the iterative process involved. Thirdly, a modified dynamic overrelaxation method is proposed, where only the relation B‐M between the magnitudes of the field vectors is used.FindingsBy approximating the actual characteristic B‐M by the relation between the components of the harmonics of the vectors B and M, the amount of computation required for the field analysis is substantially reduced. The rate of convergence of the iterative process is increased by implementing the proposed dynamic overrelaxation technique, with the convergence being further accelerated by applying the modified dynamic overrelaxation presented. The memory space is also well reduced with respect to existent methods and accurate results for nonlinear fields in a real world structure are obtained utilizing a normal size processor notebook in a time of about one‐half of one minute when no induced currents are considered and of about one minute when eddy currents induced in solid ferromagnetic parts are also fully analyzed.Originality/valueThe originality of the novel techniques presented in the paper consists in the drastic approximations proposed for the material characteristics of the nonlinear ferromagnetic media in the analysis of periodic electromagnetic fields. These techniques are highly efficient and yield accurate numerical results.
Decomposition and regularization of nonlinear anisotropic curl‐curl DAEs
Authors: Clemens Markus , Scho¨ps Sebastian , De Gersem Herbert , Bartel Andreas 
Published: December 2011

PurposeThe space discretization of eddy‐current problems in the magnetic vector potential formulation leads to a system of differential‐algebraic equations. They are typically time discretized by an implicit method. This requires the solution of large linear systems in the Newton iterations. The authors seek to speed up this procedure. In most relevant applications, several materials are non‐conducting and behave linearly, e.g. air and insulation materials. The corresponding matrix system parts remain constant but are repeatedly solved during Newton iterations and time‐stepping routines. The paper aims to exploit invariant matrix parts to accelerate the system solution.Design/methodology/approachFollowing the principle “reduce, reuse, recycle”, the paper proposes a Schur complement method to precompute a factorization of the linear parts. In 3D models this decomposition requires a regularization in non‐conductive regions. Therefore, the grad‐div regularization is revisited and tailored such that it takes anisotropies into account.FindingsThe reduced problem exhibits a decreased effective condition number. Thus, fewer preconditioned conjugate gradient iterations are necessary. Numerical examples show a decrease of the overall simulation time, if the step size is small enough. 3D simulations with large time step sizes might not benefit from this approach, because the better condition does not compensate for the computational costs of the direct solvers used for the Schur complement. The combination of the Schur approach with other more sophisticated preconditioners or multigrid solvers is subject to current research.Originality/valueThe Schur complement method is adapted for the eddy‐current problem. Therefore, a new partitioning approach into linear/non‐linear and static/dynamic domains is proposed. Furthermore, a new variant of the grad‐div gauging is introduced that allows for anisotropies and enables the Schur complement method in 3D.
Multi‐domain topology optimization with ant colony systems
Authors: Batista Lucas S. , Campelo Felipe , Guimarães Frederico G. , Ramírez Jaime A. 
Published: December 2011

PurposeThe purpose of this paper is to present a graph representation of the design space that is suitable for the ant colony optimization (ACO) method in topology optimization (TO) problems.Design/methodology/approachThe ACO is employed to obtain optimal routes in an equivalent graph representation of the discretized design space, with each route corresponding to a given distribution of material.FindingsThe problem associated with the maximization of the torque of a c‐core magnetic actuator is investigated, in which part of the yoke is discretized into a 16×8 grid and can assume three different materials: air, pure iron and a magnetic material.Research limitations/implicationsThe results of the c‐core magnetic actuator problem, which are in agreement with literature available, show the adequacy of the proposed approach to TO of electromagnetic devices.Practical implicationsThe graph representation of the design space permits the solution of topological design problems with an arbitrary number of materials.Originality/valueThe results illustrate the potential of the methodology in dealing with multi‐domain TO problems, and the possibility to extend the application to 3D problems.
Accelerated Markov chain Monte Carlo sampling in electrical capacitance tomography
Authors: Watzenig Daniel , Neumayer Markus , Fox Colin 
Published: December 2011

PurposeThe purpose of this paper is to establish a cheap but accurate approximation of the forward map in electrical capacitance tomography in order to approach robust real‐time inversion in the framework of Bayesian statistics based on Markov chain Monte Carlo (MCMC) sampling.Design/methodology/approachExisting formulations and methods to reduce the order of the forward model with focus on electrical tomography are reviewed and compared. In this work, the problem of fast and robust estimation of shape and position of non‐conducting inclusions in an otherwise uniform background is considered. The boundary of the inclusion is represented implicitly using an appropriate interpolation strategy based on radial basis functions. The inverse problem is formulated as Bayesian inference, with MCMC sampling used to efficiently explore the posterior distribution. An affine approximation to the forward map built over the state space is introduced to significantly reduce the reconstruction time, while maintaining spatial accuracy. It is shown that the proposed approximation is unbiased and the variance of the introduced additional model error is even smaller than the measurement error of the tomography instrumentation. Numerical examples are presented, avoiding all inverse crimes.FindingsProvides a consistent formulation of the affine approximation with application to imaging of binary mixtures in electrical tomography using MCMC sampling with Metropolis‐Hastings‐Green dynamics.Practical implicationsThe proposed cheap approximation indicates that accurate real‐time inversion of capacitance data using statistical inversion is possible.Originality/valueThe proposed approach demonstrates that a tolerably small increase in posterior uncertainty of relevant parameters, e.g. inclusion area and contour shape, is traded for a huge reduction in computing time without introducing bias in estimates. Furthermore, the proposed framework – approximated forward map combined with statistical inversion – can be applied to all kinds of soft‐field tomography problems.
Adaptive strategies for fast frequency sweeps
Authors: Konkel Yves , Farle Ortwin , Köhler Andreas , Schultschik Alwin , Dyczij‐Edlinger Romanus 
Published: December 2011

PurposeThe purpose of this paper is to compare competing adaptive strategies for fast frequency sweeps for driven and waveguide‐mode problems and give recommendations for practical implementations.Design/methodology/approachThe paper first summarizes the theory of adaptive strategies for multi‐point (MP) sweeps and then evaluates the efficiency of such methods by means of numerical examples.FindingsThe authors' numerical tests give clear evidence for exponential convergence. In the driven case, highly resonant structures lead to pronounced pre‐asymptotic regions, followed by almost immediate convergence. Bisection and greedy point‐placement methods behave similarly. Incremental indicators are trivial to implement and perform similarly well as residual‐based methods.Research limitations/implicationsWhile the underlying reduction methods can be extended to any kind of affine parameter‐dependence, the numerical tests of this paper are for polynomial parameter‐dependence only.Practical implicationsThe present paper describes self‐adaptive point‐placement methods and termination criteria to make MP frequency sweeps more efficient and fully automatic.Originality/valueThe paper provides a self‐adaptive strategy that is efficient and easy to implement. Moreover, it demonstrates that exponential convergence rates can be reached in practice.
Finite element analysis of electrical machines and transformers
Authors: Schmidt Erich 
Published: December 2011

PurposeThe purpose of this paper is to discuss the state of the art of finite element analysis of electrical machines and transformers. Electrical machines and transformers are prime examples of multi‐physical systems involving electromagnetics, thermal issues, fluid dynamics, structural mechanics as well as acoustic phenomena. An accurate operational performance with different electrical and mechanical load situations is more and more evaluated using various numerical analysis methods including the couplings between the various physical domains. Therefore, numerical analysis methods are increasingly utilized not only for the verification of contractual values of existing machines, but also for the initial design process and for the design optimization of new machines.Design/methodology/approachThe finite element method is the most powerful numerical analysis method for such multi‐physical devices. Since optimizations with respect to the overall performance and also the total manufacturing costs will become more important, the utilization of coupled multi‐physical analyses is of growing interest. For the fast and powerful application of this numerical analysis method, special attention should be given to the requirements of these electromagnetic devices.FindingsVarious methods of coupling the different physical domains of multi‐field finite element analyses are described. Thereby, weakly coupled cascade algorithms can be used with most problems in the field of electrical machines and transformers. On the other hand, a prime objective is to derive comprehensive, multi‐physical simulation models which are easily incorporated into design tools used by engineering professionals.Research limitations/implicationsThe development of robust and reliable computer‐aided tools for an optimal design of multi‐physical devices such electrical machines and transformers has to argue about the best possible coupling of various simulation methods. Special consideration shall be paid more and more to a treatment of uncertainties and tolerances by means of statistical and probabilistic approaches.Originality/valueThe paper discusses state of the art of finite element analyses of the mentioned devices. Various optimized methods of modelling and analysis concerning the repetitive structure of electrical machines for electromagnetic analyses are compared with their advantages and drawbacks. Further, various methods of coupling the different domains of multi‐field analyses in case of electrical machines and transformers are described.
Stress zone imaging in steel plates of electrical machines
Authors: Neumayer Markus , Watzenig Daniel , Brandstätter Bernhard 
Published: December 2011

PurposeThe purpose of this paper is to demonstrate an inverse problem approach for the determination of stress zones in steel plates of electrical machines. Steel plates of electrical machines suffer large mechanical stress by processes like cutting or punching during the fabrication. The mechanical stress has effects on the electrical properties of the steel, and thus on the losses of the machine.Design/methodology/approachIn this paper, the authors present a sensor arrangement and an appropriate algorithm for determining the spatial permeability distribution in steel plates. The forward problem for stress zone imaging is explained and an appropriate numerical solution technique is proposed. Then an inverse problem formulation is introduced and the nature of the problem is analyzed.FindingsBased on sensitivity analysis, different measurement procedures are compared and a measurement setup is suggested. Further the ill‐posed nature of the inverse problem is analyzed by the Picard condition.Practical implicationsBecause of the increased losses due to stress zones, the quantification of stress effects is of interest to adjust the production process. Stress zone imaging is a first approach for the application of an imaging system to quantify these material defects.Originality/valueThis paper presents a simulation study about the applicability of an inverse problem for stress zone imaging and presents first reconstruction results. Further, the paper discusses several issues about stress zone imaging for the ongoing research.
I have seen the future and it sucks: reactionary reflections on reading, writing and research
Authors: Brown Stephen 
Published: December 2011

PurposeReading and writing are crucial components of the research process and academic life as a whole. The purpose of this paper is to ask if conventional reading and writing practices are fit for marketing purpose.Design/methodology/approachThe paper consists of an extended autobiographical essay, which reflects on the relevance of academic research output. The concerns of marketing thought leaders are also incorporated as required.FindingsAcademic articles are unreadable and unread. This is due to extant writing practices which result in characterless papers with little reader appeal.Research limitations/implicationsThe best way forward is to look back at the approaches that prevailed prior to marketing's mid‐'60s “scientific revolution”. If adopted, they'll make learned research papers and monographs much more readable than they are at present.Practical implicationsIf marketing academics embrace this paper's recommendations, their writings are more likely to be read and acted upon by practitioners, policy makers and other important stakeholders.Originality/valueThe style of the article is in keeping with the content. It demonstrates as well as describes.
Internal and external pressures
Authors: Turcato Carolina , Barin‐Cruz Luciano , Avila Pedrozo Eugenio 
Published: December 2011

PurposeThis study aims to investigate how an organic cotton production network learns to maintain its hybrid network and its sustainability in the face of internal and external pressures.Design/methodology/approachA qualitative case study was conducted in Justa Trama, a Brazilian‐based organic cotton production network formed by six members with different roles and organisational logics.FindingsThe study contributes to the literature on hybrid organisations by suggesting that in the case of networks, a compromise strategy is required at the internal level and a manipulation strategy is required at the external level. The network has to learn how to engineer a compromise among internal members and to enforce change among external institutions to maintain its sustainability.Social implicationsThe study was performed in Brazil, a country with serious social and environmental problems. The study thus informs managers of social economy organisations on how to deal with internal and external pressures to maintain their organisation's sustainability as well as policy makers on the importance of these alternative organisations and the importance of specific legislation to stimulate this type of initiative.Originality/valueThe body of research on how hybrid organisations learn to deal with the mutual influence of internal organisational responses and changes in external institutions is limited. Furthermore, this mutual influence has rarely been studied in the context of networks, in which multiple members have to work together to achieve organisational and network‐level objectives as well as to respond to institutional pressures.
Introducing sustainability into business education contexts using active learning
Authors: MacVaugh Jason , Norton Mike 
Published: December 2011

PurposeThe purpose of this paper is to explore how active learning may help address the legitimacy and practicability issues inherent in introducing education for sustainability into business‐related degree programs.Design/methodology/approachThe focus of this study is the experience of the authors in the development and implementation of education for sustainability within their business‐related higher education programs. To address the inherent challenges of the task, they apply the principles of active learning, with substantial use of problem‐based learning, in the classroom and engage in a process of staff development in their personal time. The method used is a simplified version of action research where the authors worked together over two years and then reflected on the experience through interviews and extensive discussions with each other, with their respective teaching teams, and with sustainability educators from outside of their programs.FindingsThe findings suggest that active learning approaches move learners away from dependence on (possibly illegitimate and unprepared) educators and towards a personal responsibility approach. This also means accepting that learners are free to understand sustainability in a “global” sense or instead choose only its “business as usual” applications.Originality/valueThe paper provides a useful insight into the practical value of active learning for educators grappling with the dilemma of delivering globally responsible business and/or management‐related education programs.
Reflecting on the delivery of a structured alcohol and drug group in a medium‐secure forensic unit
Authors: Edwards Richard , Guy Ruth , Bartholomew Mark , Buckland Rosie 
Published: December 2011

PurposeThis review aims to discuss the planning, implementation and evaluation of a 24‐session alcohol and drug group for eight service users, based on the Behavioural Treatment for Substance Abuse in Severe and Persistent Mental Illness Model (BTSAS), delivered by a group of multi‐disciplinary staff in a medium secure forensic setting.Design/methodology/approachEvaluation tools were completed pre‐ and post‐group to measure attendee outcomes and perceptions of their group experience.FindingsThe group programme was well received, although adaptations to meet specific medium‐secure needs will be required for future group work.Practical implicationsThe development and implementation of the group has raised awareness within the medium‐secure setting, facilitating a less punitive and more collaborative response.Originality/valueThe paper highlights interventions to support the medium‐secure setting to develop a more pragmatic bespoke response to meet alcohol and drug needs.
Building capacity of local governments, service users and carers to scale up provision for community mental health services in Africa: a case study of Kenya and Uganda
Authors: Kingori Joyce , Angela Ntulo Christina 
Published: December 2011

PurposeThe purpose of this case study is to describe the experiences of a development organization operating in Africa to make mental health services accessible to communities in Kenya and Uganda through partnerships. The lessons that can be learnt from this work are also considered.Design/methodology/approachThe paper is a case study that builds on operations research gathered over five to seven years by the authors who have managed the country mental health programmes in Uganda and Kenya. The case study describes the problem of mental illness and its magnitude in Kenya and Uganda, and why it is important that this is addressed. Existing mechanisms in place and gaps in current service provision are also discussed.FindingsMethods used to address gaps in current service provision include capacitating different service providers, their roles and their contribution to community mental health. The inclusion and training of non‐psychiatrists can contribute to the management, treatment and recovery of people with mental health problems in African communities.Research limitations/implicationsThe case study is limited in its applicability in full to other low to middle income countries (LMICs). Causality cannot be established between improvement in access and training of the different health service providers.Practical implicationsThe case study gives practical experiences that practitioners in LMICs can further test in improving access to community‐based mental health services. These experiences can help to form a promising practice in how LMICs can reduce health workforce gaps in mental health and planners can consider using this to reduce such gaps.Social implicationsThe case study shows how the participation of service users and other stakeholders and using family resources can bring ownership and sustainability of mental health care at the community level.Originality/valueThe case study adds value to practice and social development theories and models of care.