bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of reconstructed 3D VMEC equilibria to match effects of toroidally rotating discharges in DIII-D
Authors: Wingen A. , Wilcox R.S. , Cianciosa M.R. , Seal S.K. , Unterberg E.A. , Hanson J.M. , Hirshman S.P. , Lao L.L. , Logan N.C. , Paz-Soldan C. , Shafer M.W.
Published: October 2016

A technique for tokamak equilibrium reconstructions is used for multiple DIII-D discharges, including L-mode and H-mode cases when weakly 3D fields

(
δ
B

/

B
∼

10

−
3

)

are applied. The technique couples diagnostics to the non-linear, ideal MHD equilibrium solver VMEC, using the V3FIT code, to find the most likely 3D equilibrium based on a suite of measurements. It is demonstrated that V3FIT can be used to find non-linear 3D equilibria that are consistent with experimental measurements of the plasma response to very weak 3D perturbations, as well as with 2D profile measurements. Observations at DIII-D show that plasma rotation larger than 20 krad s−1 changes the relative phase between the applied 3D fields and the measured plasma response. Discharges with low averaged rotation (10 krad s−1) and peaked rotation profiles (40 krad s−1) are reconstructed. Similarities and differences to forward modeled VMEC equilibria, which do not include rotational effects, are shown. Toroidal phase shifts of up to

30

°

are found between the measured and forward modeled plasma responses at the highest values of rotation. The plasma response phases of reconstructed equilibra on the other hand match the measured ones. This is the first time V3FIT has been used to reconstruct weakly 3D tokamak equilibria.
On particles in equilibrium on the real line
Authors: Georgakopoulos Agelos , Kolountzakis Mihail
Published: October 2016

We study equilibrium configurations of infinitely many identical particles on the real line or finitely many particles on the circle, such that the (repelling) force they exert on each other depends only on their distance. The main question is whether each equilibrium configuration needs to be an arithmetic progression. Under very broad assumptions on the force we show this for the particles on the circle. In the case of infinitely many particles on the line we show the same result under the assumption that the maximal (or the minimal) gap between successive points is finite (positive) and assumed at some pair of successive points. Under the assumption of analyticity for the force field (e.g. the Coulomb force) we deduce some extra rigidity for the configuration: knowing an equilibrium configuration of points in a half-line determines it throughout. Various properties of the equlibrium configuration are proved.
Embeddings of algebras in derived categories of surfaces
Authors: Belmans Pieter , Raedschelders Theo
Published: October 2016

By a result of Orlov there always exists an embedding of the derived category of a finite-dimensional algebra of finite global dimension into the derived category of a high-dimensional smooth projective variety. In this article we give some restrictions on those algebras whose derived categories can be embedded into the bounded derived category of a smooth projective surface. This is then applied to obtain explicit results for hereditary algebras.
On the complexity of the chip-firing reachability problem
Authors: Hujter Bálint , Kiss Viktor , Tóthmérész Lilla
Published: October 2016

In this paper, we study the complexity of the chip-firing reachability problem. We show that for Eulerian digraphs, the reachability problem can be decided in strongly polynomial time, even if the digraph has multiple edges. We also show a special case when the reachability problem can be decided in polynomial time for general digraphs: if the target distribution is recurrent restricted to each strongly connected component. As a further positive result, we show that the chip-firing reachability problem is in co-NP for general digraphs. We also show that the chip-firing halting problem is in co-NP for Eulerian digraphs.
yMap: an automated method to map yeast variants to protein modifications and functional regions
Authors: Arslan Ahmed , van Noort Vera
Published: October 2016

Recent advances in sequence technology result in large datasets of sequence variants. For the human genome, several tools are available to predict the impact of these variants on gene and protein functions. However, for model organisms such as yeast such tools are lacking, specifically to predict the effect of protein sequence altering variants on the protein level. We present a python framework that enables users to map in a fully automated fashion large set of variants to protein functional regions and post-translationally modified residues. Furthermore, we provide the user with the possibility to retrieve predicted functional information on modified residues from other resources for example that are predicted to play a role in protein-protein interactions. The results are complemented by statistical tests to highlight the significance of underlying functions and pathways affected by mutations. We show the application of this package on a yeast dataset derived from a recent evolutionary experiment on adaptation to ethanol.

Availability and Implementation

The package is available from https://github.com/CSB-KUL/yMap and is implemented in Python.

Supplementary information

Supplementary data are available at Bioinformatics online.
Equal Distribution of Mating Type Alleles and the Presence of Strobilurin Resistance in Algerian Zymoseptoria tritici Field Populations
Authors: Meamiche Neddaf Hayet , Aouini Lamia , Bouznad Zouaoui , Kema Gert H. J.
Published: October 2016

Zymoseptoria tritici, the causal agent of septoria tritici blotch, is an important wheat pathogen responsible for high yield losses worldwide. The assessment of the distribution of both mating type idiomorphs was studied in several wheat-growing areas in North Algeria. Both mating types occurred at all spatial scales tested and showed an equal frequency distribution at the country level, with 53% for Mat1-1 and 47% for Mat1-2. At finer scales, co-occurrence of both mating types was found in 38% of leaves analyzed and 44% of the studied lesions. Additionally, efficacy reduction of strobilurin applications prompted us to study strobilurin resistance conferred by the G143A substitution in the mitochondrial cytochrome b gene, which was found for the first time in six strains. The results suggest that the Algerian Z. tritici population undergoes frequent sexual reproduction mirrored by co-occurrence of both mating types, which likely will rapidly increase the fraction of strobilurin-resistant isolates in the Algerian population, as has been shown in all other regions where strobilurin resistance surfaced.
Development and Validation of an Infection Risk Model for Bacterial Canker of Kiwifruit, Using a Multiplication and Dispersal Concept for Forecasting Bacterial Diseases
Authors: Beresford R. M. , Tyson J. L. , Henshall W. R.
Published: October 2016

A weather-based disease prediction model for bacterial canker of kiwifruit (known worldwide as Psa; Pseudomonas syringae pv. actinidiae biovar 3) was developed using a new mechanistic scheme for bacterial disease forecasters, the multiplication and dispersal concept. Bacterial multiplication is estimated from a temperature function, the M index, accumulated from hourly air temperature over 3 days for hours when the leaf canopy is wet. Rainfall provides free water to move inoculum to infection sites, and the daily risk indicator, the R index, is the 3-day accumulation of the M index output on days with total rainfall >1 mm; otherwise, R is zero. The model was field-tested using potted kiwifruit trap plants exposed for discrete periods in infected kiwifruit orchards to identify when leaf infection occurred. In a 9-week study during spring, the R index predicted leaf-spot intensity with high accuracy (R2= 93%) and, in an 82-week seasonal accuracy study, prediction of infection incidence was most accurate from spring to late summer and lower during other times. To implement the risk model for the New Zealand kiwifruit industry, a modified risk index, R’, used relative humidity (RH) >81% instead of wetness, so that 2- and 6-day weather forecasts of RH could be used. Risk index values were affected by the shape of the temperature function and an alternative ‘low temperature’ function for the M index was identified that could be used in climates in which high temperatures are known to limit Psa development during some parts of the year. This study has shown how infection risk for bacterial diseases can be conceptualized as separate processes for temperature-dependent bacterial multiplication and rain-dependent dispersal and infection. This concept has potentially wide application for bacterial disease prediction in the same way that the infection monocycle concept has had for fungal disease prediction.
CatB is Critical for Total Catalase Activity and Reduces Bactericidal Effects of Phenazine-1-Carboxylic Acid on Xanthomonas oryzae pv. oryzae and X. oryzae pv. oryzicola
Authors: Pan Xiayan , Wu Jian , Xu Shu , Duan Yabing , Zhou Mingguo
Published: October 2016

Rice bacterial leaf blight, caused by Xanthomonas oryzae pv. oryzae, and rice bacterial leaf streak, caused by X. oryzae pv. oryzicola, are major diseases of rice. Phenazine-1-carboxylic acid (PCA) is a natural product that is isolated from Pseudomonas spp. and is used to control many important rice diseases in China. We previously reported that PCA disturbs the redox balance, which results in the accumulation of reactive oxygen species in X. oryzae pv. oryzae. In this study, we found that PCA significantly upregulated the transcript levels of catB and katE, which encode catalases, and that PCA sensitivity was reduced when X. oryzae pvs. oryzae and oryzicola were cultured with exogenous catalase. Furthermore, catB deletion mutants of X. oryzae pvs. oryzae and oryzicola showed dramatically decreased total catalase activity, increased sensitivity to PCA, and reduced virulence in rice. In contrast, deletion mutants of srpA and katG, which also encode catalases, exhibited little change in PCA sensitivity. The results indicate that catB in both X. oryzae pvs. oryzae and oryzicola encodes a catalase that helps protect the bacteria against PCA-induced stress.
Chromosomal dynamics predicted by an elastic network model explains genome-wide accessibility and long-range couplings
Authors: Sauerwald Natalie , Zhang She , Kingsford Carl , Bahar Ivet
Published: October 2016

Understanding the three-dimensional (3D) architecture of the chromatin and its relation to gene expression and regulation is fundamental to understanding how the genome functions. Advances in Hi-C technology now permit us to have a glimpse into the 3D genome organization and identify topologically associated domains (TADs), but we still lack an understanding of the structural dynamics of chromosomes. The dynamic couplings between regions separated by large genomic distances (> 50 megabases) have yet to be characterized. We adapted a well-established protein-modeling framework, the Gaussian Network Model (GNM), to the task of modeling chromatin dynamics using Hi-C contact data. We show that the GNM can identify structural dynamics at multiple scales: it can quantify the fluctuations in the positions of gene loci, find large genomic compartments and smaller TADs that undergo en-bloc movements, and identify dynamically coupled distal regions along the chromosomes. We show that the predictions of the GNM correlate well with DNase-seq and ATAC-seq measurements on accessibility, the previously identified A and B compartments of chromatin structure, and pairs of interacting loci identified by ChIA-PET. We describe a method to use the GNM to identify novel cross-correlated distal domains (CCDDs) representing regions of long-range dynamic coupling and show that CCDDs are often associated with increased gene coexpression using a large-scale analysis of 212 expression experiments. Together, these results show that GNM provides a mathematically well-founded unified framework for assessing chromatin dynamics and the structural basis of genome-wide observations.
Identification of new bacterial type III secreted effectors with a recursive Hidden Markov Model profile-alignment strategy
Authors: Cheng Xi , Hui Xinjie , White Aaron P. , Guo Zhirong , Hu Yueming , Wang Yejun
Published: October 2016

To identify new bacterial type III secreted effectors is computationally a big challenge. At least a dozen machine learning algorithms have been developed, but so far have only achieved limited success. Sequence similarity appears important for biologists but is frequently neglected by algorithm developers for effector prediction, although large success was achieved in the field with this strategy a decade ago. In this study, we propose a recursive sequence alignment strategy with Hidden Markov Models, to comprehensively find homologs of known YopJ/P full-length proteins, effector domains and N-terminal signal sequences. Using this method, we identified 155 different YopJ/P-family effectors and 59 proteins with YopJ/P N-terminal signal sequences from 27 genera and more than 70 species. Among these genera, we also identified one type III secretion system (T3SS) fromUliginosibacteriumand two T3SSs fromRhizobacterfor the first time. Higher conservation of effector domains, N-terminal fusion of signal sequences to other effectors, and the exchange of N-terminal signal sequences between different effector proteins were frequently observed for YopJ/P-family proteins. This made it feasible to identify new effectors based on separate similarity screening for the N-terminal signal peptides and the effector domains of known effectors. This method can also be applied to search for homologues of other known T3SS effectors.
An actor-network theory perspective to study the non-adoption of a collaborative technology intended to support online community participation
Authors: Rivera Gibran , Cox Andrew M.
Published: October 2016

Purpose

The purpose of this paper is to explore the value of Actor-network theory as an approach to explain the non-adoption of collaborative technology.

Design/Methodology/Approach

The notion of translation and related concepts pertaining to Actor-network theory are used to explore the case of non-participation in an organizational online community. Semi-structured interviews were conducted with 30 HR professionals belonging to a multi-campus university system in Mexico.

Findings

The study shows that participation in the online community did not occur as expected by those promoting its use. An initial inductive analysis showed that the factors that undermine participation had to do with the interface design of the technology and the individual motivations and benefits derived from participation. A second analysis, using ANT showed how processes of negotiation, conflict, enrolment, alignment, and betrayal that occurred during the emergence and evolution of the new network played a critical role in technology adoption leading to the dissolution of the initiative to adopt the collaborative technology.

Originality/value

The study shows the value of ANT as a tool to better understand the adoption and use of collaborative technology. The analysis goes beyond existing explanations of participation, which tend to focus attention on matters such as the interface design or the personal motivations and benefits derived from participation. It does so by moving away from solely looking at what occurs within the boundaries of a community and understanding the context within which it is being introduced. It prompts the analysis of moments of problematization, interessement, enrolment, and mobilization to explore the adoption process, including the role of non-human actors.
The votes are in: a process for selecting reference books and managing the reference budget
Authors: Collins Susan L.
Published: October 2016

Purpose

The purpose of this study is to describe the process that is used for selecting reference books and managing the reference budget at one academic library reference unit. While there have been articles written on reference collection development, none have explained the process in detail.

Design/methodology/approach

This paper describes the process used to select reference books via a voting system and how the budget is managed over ordering periods.

Findings

Using the system described, librarians can effectively manage a reference budget that fairly distributes resources across different subjects and gives selectors greater control of the resources they purchase.

Originality/value

This is a unique book selection and ordering system that has not been described in the literature.
Reducing carbon footprint of facilities using a facility management approach
Authors: Dixit Manish K. , Culp Charles H. , Fernandez-Solis Jose L. , Lavy Sarel
Published: October 2016

Purpose

The purpose of this paper is to emphasize the importance of a life cycle approach in facilities management practices to reduce the carbon footprint of built facilities. A model to holistic life cycle energy and carbon reduction is also proposed.

Design/methodology/approach

A literature-based discovery approach was applied to collect, analyze and synthesize the results of published case studies from around the globe. The energy use results of 95 published case studies were analyzed to derive conclusions.

Findings

A comparison of energy-efficient and conventional facilities revealed that decreasing operating energy may increase the embodied energy components. Additionally, the analysis of 95 commercial buildings indicated that nearly 10 per cent of the total US carbon emissions was influenced by facilities management practices.

Research limitations/implications

The results were derived from case studies that belonged to various locations across the globe and included facilities constructed with a variety of materials.

Practical implications

The proposed approach to holistic carbon footprint reduction can guide facility management research and practice to make meaningful contributions to the efforts for creating a sustainable built environment.

Originality/value

This paper quantifies the extent to which a facilities management professional can contribute to the global efforts of reducing carbon emission.
Depoliticised activism? Ambivalence and pragmatism at the COP16
Authors: Sealey-Huggins Leon Ayo
Published: October 2016

Purpose

The purpose of this paper is to interrogate the forms of activist organisation at the United Nations Framework Convention on Climate Change COP16 in Cancún and reveals their attempts to create alternatives to a seemingly “depoliticised” response to climate change. The paper argues that existing attempts to challenge depoliticisation face problems in the form of governmental opposition, limitations on forms of organising, and internal conflicts between activists.

Design/methodology/approach

This paper utilises “scholar-activist” engagement with actors at alternative “popular” spaces established outside the COP16 in Cancún, Mexico. It draws upon extensive participant observation and in-depth interviews with 20 English-speaking activists.

Findings

Common among activists was a concern to try and model alternative forms of social relations, to the depoliticised and hierarchical forms found in the formal Conference of Parties, via forms of anarchist-influenced “prefigurative” practice. In spite, or perhaps because, of perceived challenges to attempts to organise their political praxis along non-hierarchical lines, many people were ambivalent about the scope of their action, revealing highly reflexive accounts of the limitations of these whilst simultaneously remaining pragmatic in trying to make the most of their involvement.

Originality/value

The paper helps us to better understand the potential to politicise climate change. Understanding the challenges faced by activists is important for trying to organise more effective political responses to climate injustice. It is suggested that we must understand activists’ responses to these challenges and limitations in terms of the pragmatism in response that allows them to continue to invest in activism in the face of unsuccessful actions.
Innovation policy in a global economy
Authors: Potts Jason
Published: October 2016

Purpose

The purpose of this paper is to examine how national innovation policies strategically interact to form emergent de facto global entrepreneurship and innovation policies.

Design/methodology/approach

Reviews the innovation economics theory and policy literature, synthesizing the existing work into three models (autarky, cooperation and competition), then adds four new models of strategic interaction (asymmetric information, duopolistic competition, competitive factor mobility and complementary assets).

Findings

The different models predict very different outcomes. Therefore, it matters which model is true. Entrepreneurship and innovation policy needs to start with an improved science of strategic global interaction of national innovation policy.

Research limitations/implications

Conceptual approach only, without empirical analysis, calls for empirical analysis to test the different models.

Practical implications

Points to the problem of absence of global coordination in innovation policy arising from strategic interactions between national innovation policies. Recognizes that entrepreneurship public policy is caught in this strategic game, and that there are missing global institutions here.

Social implications

Improved innovation policy should enable more effective entrepreneurial environments.

Originality/value

Proposes seven models for understanding global strategic interaction of innovation policy, out of which four are new. These new ones are highly relevant to entrepreneurship policy.
Exploration of multi-layered knowledge sharing participation: the roles of perceived benefits and costs
Authors: Sedighi Mohammadbashir , van Splunter Sander , Brazier Frances , van Beers Cees , Lukosch Stephan
Published: October 2016

Purpose

This paper aims to explore participants’ perceived benefits and costs that influence the quantity and the quality of voluntary participation in knowledge networks in a resources-constrained economy.

Design/methodology/approach

A conceptual model of perceived benefits and costs of knowledge sharing is designed on the basis of literature. The influence of perceived benefit and cost on perceived quantity and quality of knowledge sharing are assessed on the basis of a survey with 283 participants in a business context within a resource-restrained economy.

Findings

The results indicate that reputation, reciprocity and altruism are perceived to benefit quantity of participation, whereas reciprocity, altruism and knowledge self-efficacy are perceived to benefit the quality of participation in knowledge networks. Effort and time have a negative impact on both quantity and quality of participation in knowledge sharing.

Research limitations/implications

This study provides insights into the factors that influence acceptance and use of knowledge networks and can thus influence business policies.

Originality/value

This exploratory study explores both perceived benefits and costs of participation in knowledge sharing in a resource-constrained economy.
Commercial property tax in the UK: business rates and rating appeals
Authors: Greenhalgh Paul Michael , Muldoon-Smith Kevin , Angus Sophie
Published: October 2016

Purpose

The purpose of this paper is to investigate the impact of the introduction of the business rates retention scheme (BRRS) in England which transferred financial liability for backdated appeals to LAs. Under the original scheme, business rates revenue, mandatory relief and liability for successful appeals is spilt 50/50 between central government and local government which both share the rewards of growth and bear the risk of losses.

Design/methodology/approach

The research adopts a microanalysis approach into researching local government finance, conducting a case study of Leeds, to investigate the impact of appeals liability and reveal disparities in impact, through detailed examination of multiple perspectives in one of the largest cities in the UK.

Findings

The case study reveals that Leeds, despite having a buoyant commercial economy driven by retail and service sector growth, has been detrimentally impacted by BRRS as backdated appeals have outweighed uplift in business rates income. Fundamentally BRRS is not a “one size fits all” model – it results in winners and losers – which will be exacerbated if local authorities get to keep 100 per cent of their business rates from 2020.

Research limitations/implications

LAs’ income is more volatile as a consequence of both the rates retention and appeals liability aspects of BRRS and will become more so with the move to 100 per cent retention and liability.

Practical implications

Such volatility impairs the ability of local authorities to invest in growth at the same time as providing front line services over the medium term – precisely the opposite of what BRRS was intended to do. It also incentivises the construction of new floorspace, which generates risks overbuilding and exacerbating over-supply.

Originality/value

The research reveals the significant impact of appeals liability on LAs’ business rates revenues which will be compounded with the move to a fiscally neutral business rates system and 100 per cent business rates retention by 2020.
Reflecting sustainability in property valuation – a progress report
Authors: Michl Peter , Lorenz David , Lützkendorf Thomas , Sayce Sarah
Published: October 2016

Purpose

The purpose of this paper is to report on the findings of a survey conducted by the Royal Institution of Chartered Surveyors (RICS) to discuss the extent to which qualified valuers have adapted their valuation practices in the light of guidance published by RICS in respect of sustainability and commercial property. The findings are placed within a wider debate between assessment of market value and investment value (worth).

Design/methodology/approach

The paper is a theoretical discussion incorporating the results from an empirical survey of valuation practitioners.

Findings

The paper reveals that guidance published by RICS in 2011 has achieved limited, but variable, impact in terms of impacting on valuation practice due to a combination of factors including lack of knowledge of the guidance, non-requirement of clients to request sustainability reporting within valuations, paucity of data. It found that where worth (investment value) is required, sustainability factors are more likely to impact the calculation than where an estimate of market value is prepared. The paper identifies theoretical problems and practical barriers hindering an integration of sustainability aspects into valuation practice.

Research limitations/implications

The empirical work was conducted prior to the embedding of guidance within the mandatory provisions of the “Red Book”; the study therefore reports on a direction of travel rather than the current position. The implications for research are the requirement to enhance data capture and to seek ways to break down the barriers to more comprehensive integration of such data so that worth and market values may begin to converge.

Practical implications

The paper has practical implications for both the education of valuers which is proposed through the RenoValue project discussed in the paper and for the RICS in monitoring progress towards more specific integration within valuers’ calculations. Further, the paper identifies that clients and lenders have a key role to play through the instructions given to valuers.

Social implications

There is now widespread recognition that properties which are not resource efficient and which are not equipped to flex to changing occupier needs may not currently be “future proofed” in investment value terms and are likely to see value erosion over time. Further, buildings have a key role in terms of climate change policy. Whilst new buildings can be mandated to meet improved efficiency standards, the ways in which buildings owners can be encouraged to upgrade will be important moving forward. One way is through a value chain response.

Originality/value

The survey is the most comprehensive investigation of valuer’s practice in relation to sustainability and the assessment of market value and worth undertaken. This provides a unique insight into the effectiveness of professional guidance and enables an informed discussion as to appropriate ways to enhance guidance moving forward.
Principles of management efficiency and organizational inefficiency
Authors: Lin (Jeffrey Forrest) Yi , Orvis Bruce
Published: October 2016

Purpose

The purpose of this paper is to introduce two important principles of efficiency, one on the management of a business entity and the other on the structure of employees’ efforts and devotion toward realizing the mission of their organization.

Design/methodology/approach

All discussion and reasoning are established on some of the traditional methods of microeconomics and on the basis of the systemic yoyo model. Here, the yoyo model plays the role of intuition, while the traditional methods are utilized to present the exact details underneath the systemic thinking.

Findings

What is discovered include how management efficiency can be achieved by being flexible in terms of allowing individual employees to have conflicting personal values and how organizational inefficiency always exists no matter how the business entity is set up.

Research limitations/implications

The established results are applicable in all business scenarios without foreseeable limitations.

Practical implications

By understanding these results, business managers could simply devote more of their time and effort on being flexible in terms of management styles and focusing on the “big” picture of the corporation instead of dwelling on how to improve employees’ efficiencies.

Originality/value

This paper establishes two very important, very useful results for managers. These results are expected to enrich the managerial understanding on what can be improved and what cannot.
Co-creating luxury brands in an emerging market
Authors: Stiehler Beate Elizabeth
Published: October 2016

Purpose

The purpose of this paper is to explore consumer meaning-making and brand co-creation and the role of brand value and the consumption context of luxury goods in the emerging South African market.

Design/methodology/approach

An extant segmentation approach that classifies luxury brand consumers into four different segments was used to guide the identification of a total of 16 luxury consumers with whom in-depth interviews were conducted.

Findings

The findings identify differences between four consumer segments’ levels of brand knowledge and indicate how these differing levels produce interesting meanings assigned to luxury brands which in turn co-create the brands. A framework is also proposed that maps each of the four luxury segments according to the value they derive from luxury brands and the context in which luxury consumption holds the most meaning for each segment.

Practical implications

Managerial recommendations concerning the implications of consumers assigning meaning and value to luxury brands and recommendations pertaining to the managing and positioning of luxury brands to each of the four luxury segments in this market are proposed.

Originality/value

The study provides interesting insights with regards to how consumers assign meaning and value to luxury brands in the emerging South African market. The proposed framework also uniquely demonstrates underlying behaviours within each of the four luxury segments and contributes to a better understanding of how and why these segments consume luxury brands.
Polygonal model based cutter location data generation with offset error compensation
Authors: Wen Hao , Gao Jian , Chen Xin
Published: October 2016

Purpose

As manufacturing technology has developed, digital models from advanced measuring devices have been widely used in manufacturing sectors. To speed up the production cycle and reduce extra errors introduced in surface reconstruction processes, directly machining digital models in the polygonal stereolithographyformat has been considered as an effective approach in rapid digital manufacturing. In machining processes, Cutter Location (CL) data for numerical control (NC) machining is generated usually from an offset model. This model is created by offsetting each vertex of the original model along its vertex vector. However, this method has the drawback of overcut to the offset model. The purpose of this paper is to solve the overcut problem through an error compensation algorithm to the vertex offset model.

Design/methodology/approach

Based on the analysis of the vertex offset method and the offset model generated, the authors developed and implemented an error compensation method to correct the offset models and generated the accurate CL data for the subsequent machining process. This error compensation method is verified through three polygonal models and the tool paths generated were used for a real part machining.

Findings

Based on the analysis of the vertex offset method and the offset model generated, the authors developed an error compensation method to correct the offset models and generated the accurate CL data for the subsequent machining process. The developed error compensation algorithm can effectively solve the overcut drawback of the vertex offset method.

Research limitations/implications

The error compensation method to the vertex offset model is used for generating the CL data with the using of a ball-end cutter.

Practical implications

On the study of CL data generation for a STL model, most of the current studies are focused on the determination of the offset vectors of the vertexes. The offset distance is usually fixed to the radius of the cutter used. Thus, the overcut problem to the offset model is inevitable and has not been much studied. The authors propose an effective approach to compensate the insufficient distance of the offset vertex and solve the overcut problem.

Social implications

The directly tool paths generation from a STL model can reduce the error of surface reconstruction and speed up the machining progress.

Originality/value

The authors investigate the overcut problem occurred in vertex offset for CL data generation and present a new error compensation algorithm for generating the CL data that can effectively solve the overcut problem.
Process capability study of three dimensional printing as casting solution for non ferrous alloys
Authors: Kumar Rajesh , Singh Rupinder , Ahuja IPS
Published: October 2016

Purpose

The purpose of this paper is to investigate the process capability of three-dimensional printing (3DP)-based casting solutions for non-ferrous alloy (NFA) components.

Design/methodology/approach

After selection and design of benchmark, prototypes for six different NFA materials were prepared by using 3DP (ZCast process)-based shell moulds. Coordinate measuring machine has been used for calculating the dimensional tolerances of the NFA components. Consistency with the tolerance grades of the castings has been checked as per IT grades.

Findings

The results of process capability investigation highlight that the 3DP process as a casting solution for NFA component lies in ±5sigma (s) limit, as regards to dimensional accuracy is concerned. Further, this process ensures rapid production of pre-series industrial prototypes for NFA. Final components prepared are also acceptable as per ISO standard UNI EN 20,286-I (1995).

Originality/value

This research work presents capability of the 3DP process supported with experimental data on basis of various process parameters for the tolerance grade of NFA castings. These statistics can help to enhance the application of 3DP-based NFA casting process in commercial foundry industry.
The effect of EBM process parameters upon surface roughness
Authors: Klingvall Ek Rebecca , Rännar Lars-Erik , Bäckstöm Mikael , Carlsson Peter
Published: October 2016

Purpose

The surface roughness of products manufactured using the additive manufacturing (AM) technology of electron beam melting (EBM) has a special characteristic. Different product applications can demand rougher or finer surface structure, so the purpose of this study is to investigate the process parameters of EBM to find out how they affect surface roughness.

Design/methodology/approach

EBM uses metal powder to manufacture metal parts. A design of experiment plan was used to describe the effects of the process parameters on the average surface roughness of vertical surfaces.

Findings

The most important electron beam setting for surface roughness, according to this study, is a combination of “speed and current” in the contours. The second most important parameter is “contour offset”. The interaction between the “number of contours” and “contour offset” also appears to be important, as it shows a much higher probability of being active than any other interaction. The results show that the “line offset” is not important when using contours.

Research limitations/implications

This study examined “contour offset”, “number of contours”, “speed in combination with current” and “line offset”, which are process parameters controlling the electron beam.

Practical implications

The surface properties could have an impact on the product’s performance. A reduction in surface processing will not only save time and money but also reduce the environmental impact.

Originality/value

Surface properties are important for many products. New themes containing process parameters have to be developed when introducing new materials to EBM manufacturing. During this process, it is very important to understand how the electron beam affects the melt pool.
Maternal factors and the risk of birth defects after IVF and ICSI: a whole of population cohort study
Authors: Davies MJ , Rumbold AR , Marino JL , Willson K , Giles LC , Whitrow MJ , Scheil W , Moran LJ , Thompson JG , Lane M , Moore VM
Published: October 2016

Objective

To assess the contribution of maternal factors to major birth defects after in vitro fertilisation (IVF), intracytoplasmic sperm injection (ICSI), and natural conception.

Design

Retrospective cohort study in South Australia for the period January 1986 to December 2002.

Setting

A whole of population study.

Population

A census of all IVF and ICSI linked to registries for births, pregnancy terminations, and birth defects (diagnosed before a child's fifth birthday).

Methods

Odds ratios (ORs) for birth defects were calculated among IVF, ICSI, and natural conceptions for maternal age, parity, pre‐pregnancy BMI, smoking, pre‐existing diseases, and conditions in pregnancy, with adjustment for confounding factors.

Main outcome measures

Birth defects classified by International Classification of Diseases (ninth revision) and British Paediatric Association (ICD9‐BPA) codes.

Results

There were 2211 IVF, 1399 ICSI, and 301 060 naturally conceived births. The unadjusted prevalence of any birth defect was 7.1, 9.9, and 5.7% in the IVF, ICSI, and natural conception groups, respectively. As expected, the risk of birth defects increased with maternal age among the natural conceptions. In contrast, for IVF and ICSI combined, relative to natural conceptions, births to women aged ≤29 years had a higher risk (adjusted odds ratio, aOR 1.42; 95% confidence interval, 95% CI 1.04–1.94), births to women aged 35–39 years had no difference in risk (aOR 1.01; 95% CI 0.74–1.37), and births to women aged ≥40 years had a lower risk of defects (aOR 0.45; 95% CI 0.22–0.92). Defects were also elevated for nulliparity, anaemia, and urinary tract infection in births after ICSI, but not after IVF.

Conclusions

The usual age–birth defect relationship is reversed in births after IVF and ICSI, and the associations for other maternal factors and defects vary between IVF and ICSI.

Tweetable abstract

Risk of birth defects in women over 40 years is lower after infertility treatment than for natural conceptions.
Experiences and characteristics of women seeking and completing at‐home medical termination of pregnancy through online telemedicine in Ireland and Northern Ireland: a population‐based analysis
Authors: Aiken ARA , Gomperts R , Trussell J
Published: October 2016

Objective

To examine the characteristics and experiences of women in Ireland and Northern Ireland seeking at‐home medical termination of pregnancy (TOP) using online telemedicine.

Design

Population‐based study.

Setting

Ireland and Northern Ireland.

Population

Between 1 January 2010 and 31 December 2015, 5650 women requested at‐home medical TOP through online telemedicine initiative Women on Web.

Methods

We examined the demographics and circumstances of women requesting medical TOP and examined the experiences of the 1023 women who completed TOP between January 2010 and December 2012. We conducted a content analysis of women's evaluations and used logistic regression to examine factors associated with lack of emotional support during and after TOP

Main outcome measures

Satisfaction with TOP; feelings before and after TOP; emotional support during TOP.

Results

Women requesting TOP were diverse with respect to age, pregnancy circumstances and reasons for seeking TOP. Among those completing TOP, 97% felt they made the right choice and 98% would recommend it to others in a similar situation. Women commonly reported serious mental stress caused by their pregnancies and their inability to afford travel abroad to access TOP. The feelings women most commonly reported after completing TOP were ‘relieved’ (70%) and ‘satisfied’ (36%). Women with financial hardship had twice the risk of lacking emotional support (odds ratio = 2.0, P < 0.001).

Conclusions

The vast majority of women who completed at‐home medical TOP through Women on Web had a positive experience. These demonstrated benefits to health and wellbeing contribute new evidence to the debate surrounding abortion laws in Ireland and Northern Ireland.

Tweetable abstract

Irish and Northern Irish women completing at‐home medical TOP report benefits for health, wellbeing and autonomy.
Factors predisposing to stone migration from the gallbladder into the common bile duct
Authors: Gan Jonathan , Chang Stephen
Published: October 2016

Aim

Endoscopic retrograde cholangiopancreatography (ERCP), followed by laparoscopic cholecystectomy (LC), has an important role in the treatment of gallstone cholangitis. The aim of the present study was to investigate the optimal timing of LC, and factors that predispose early recurrence in patients who undergo ERCP for common bile duct (CBD) stones.

Patients and Methods

A retrospective study was carried out for all patients who were treated conservatively in our hospital from 2006 to 2008. A total of 116 patients were followed up. Patients were divided into three groups: early recurrence, late recurrence and no recurrence. Risk factors evaluated included age, sex, number of stones, largest stone size, gallbladder wall thickness, CBD diameter, presence of stones in the gallbladder and CBD and the presence of pericholecystic fluid.

Results

CBD stone recurrence occurred in 29 patients (25 per cent). Fifteen patients had recurrent symptoms within 2.6 months. These patients were subsequently placed in the early recurrence group. Multivariate analysis showed that lager stone size [odds ratio (OR): 1.084, 95 per cent confidence interval (CI): 1.007–1.167, P = 0.033] is a significant risk factor for early recurrence, but older age is a protective factor (OR: 0.994, CI: 0.907–0.984, P = 0.006).

Conclusion

Gallstone size is significantly associated with early CBD stone recurrence. Advancing age is protective against early recurrence. LC should be performed within 2.6 months after the first event.
Paying a ‘Fair Share’: Multinational Corporations’ Perspectives on Taxation
Authors: Elbra Ainsley , Mikler John
Published: October 2016

Global economic integration undermines the effectiveness of national corporate taxation regimes. Being able to shift their revenues to states where they pay little tax, multinational corporations (MNCs) legally minimise what they pay. However, corporations’ reputations are precious assets that they may jeopardise if they are widely perceived to not be paying their ‘fair share’ of taxation. Does this affect corporate perspectives? We first consider the reality that the global economy is both geographically and economically concentrated. This market and geographical concentration is the source of MNCs’ power and it affects their strategic perspective on minimising tax payments. It also supports a liberal preoccupation with shareholder value that reflects the institutional context of their major headquarters: the US. Second, we analyse indices of corporate reputation to demonstrate how this perspective dominates other attributes, particularly social responsibility. Third, we consider corporate responses to recent inquiries. We find that a liberal ideological belief in free markets and a focus on shareholder value dominate corporate conceptions of legitimacy. We therefore conclude it is unlikely MNCs will voluntarily pay their fair share of tax, but that in declaring their right not to do so they have opened the way to national and international re‐regulation.
Comparison of combined antioxidants and thymoquinone in the prevention of testis ischemia – reperfusion injury
Authors: Erol B. , Sari U. , Amasyali A. S. , Ozkanli S. , Sogut S. , Hanci V. , Efiloglu O. , Danacioglu Y. O. , Engin P. , Yencilek F. , Atis G. , Yildirim A. , Alkoc O. A. , Caskurlu T.
Published: October 2016

We aimed to compare the preventive effects of combined antioxidants (CA1, 2) with a single antioxidant drug (thymoquinone; TQ) on experimental testis Ischemia/Reperfusion (I/R) injury. Thirty‐five adult male Wistar rats were divided into five groups of seven rats each: control, testis I/R, testis I/R + CA1, testis I/R + CA2, and testis I/R + TQ. After 1 h of testicular ischemia, reperfusion was achieved by detorsion for 4 h. Antioxidants were intraperitoneally administered for 30 min prior to reperfusion. All rats were sacrificed 4 h after reperfusion to evaluate the tissue levels of malondialdehyde (MDA) and total antioxidant status (TAS) and the immunohistochemical evaluation of tissue inducible and endothelial nitric acid synthase (iNOS, eNOS) and apoptosis protease‐activating factor 1 (APAF‐1). MDA levels were lower and TAS values were higher in the I/R + antioxidant groups than in the I/R group (p < 0.05). iNOS and eNOS levels in the I/R + antioxidant groups were also lower than those in the I/R group (p < 0.05). There were no significant differences between the CA groups and the TQ group according to aforementioned parameters. In addition, tissue APAF‐1 values were significantly higher in the I/R group than in the other groups. However, there was a significant difference between the TQ and CA groups in APAF‐1 levels, which were highest in the TQ group (p < 0.05). Although TQ alone increased TAS values and reduced tissue iNOS and eNOS levels, combined antioxidant treatment may more effectively reduce apoptosis and increase preventive effects in testis I/R injury.