bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural and functional characterization of CMP-N-acetylneuraminate synthetase fromVibrio cholerae
Authors: Bose Sucharita , Purkait Debayan , Joseph Deepthi , Nayak Vinod , Subramanian Ramaswamy
Published: May 2019

Several pathogenic bacteria utilize sialic acid, including host-derivedN-acetylneuraminic acid (Neu5Ac), in at least two ways: they use it as a nutrient source and as a host-evasion strategy by coating themselves with Neu5Ac. Given the significant role of sialic acid in pathogenesis and host-gut colonization by various pathogenic bacteria, includingNeisseria meningitidis,Haemophilus influenzae,Pasteurella multocidaandVibrio cholerae, several enzymes of the sialic acid catabolic, biosynthetic and incorporation pathways are considered to be potential drug targets. In this work, findings on the structural and functional characterization of CMP-N-acetylneuraminate synthetase (CMAS), a key enzyme in the incorporation pathway, fromVibrio choleraeare reported. CMAS catalyzes the synthesis of CMP-sialic acid by utilizing CTP and sialic acid. Crystal structures of the apo and the CDP-bound forms of the enzyme were determined, which allowed the identification of the metal cofactor Mg2+in the active site interacting with CDP and the invariant Asp215 residue. While open and closed structural forms of the enzyme from eukaryotic and other bacterial species have already been characterized, a partially closed structure ofV. choleraeCMAS (VcCMAS) observed upon CDP binding, representing an intermediate state, is reported here. The kinetic data suggest that VcCMAS is capable of activating the two most common sialic acid derivatives, Neu5Ac and Neu5Gc. Amino-acid sequence and structural comparison of the active site of VcCMAS with those of eukaryotic and other bacterial counterparts reveal a diverse hydrophobic pocket that interacts with the C5 substituents of sialic acid. Analyses of the thermodynamic signatures obtained from the binding of the nucleotide (CTP) and the product (CMP-sialic acid) to VcCMAS provide fundamental information on the energetics of the binding process.
Structural insight into a matured humanized monoclonal antibody HuA21 against HER2-overexpressing cancer cells
Authors: Wang Zhenyi , Cheng Liansheng , Guo Gongrui , Cheng Baoyun , Hu Siyi , Zhang Hongmin , Zhu Zhongliang , Niu Liwen
Published: May 2019

HER2, a member of the epidermal growth factor receptor (EGFR) family, has been associated with human breast, ovarian and gastric cancers. Anti-HER2 monoclonal antibodies (mAbs) have demonstrated clinical efficacy for HER2-overexpressing breast cancer. A chimeric antibody chA21 that specifically inhibits the growth of HER2-overexpressing cancer cells both in vitro and in vivo has previously been developed. To reduce a potential human anti-mouse immune response, the humanized antibody HuA21 was developed and was further subjected to affinity maturation by phage display on the basis of chA21. Here, the crystal structure of HuA21-scFv in complex with the extracellular domain of HER2 is reported, which demonstrates that HuA21 binds almost the same epitope as chA21 and also provides insight into how substitutions in HuA21 improve the binding affinity compared with chA21, which could facilitate structure-based optimization in the future. Furthermore, the effects of HuA21 variants with constant domains of different lengths were explored and it was noticed that the deletion of constant domain 1 could improve the inhibition efficacy in a cell-proliferation assay, possibly functioning via increased internalization, which might guide the design of other monoclonal antibodies.
Entropy of centrality values for topological vulnerability analysis of water distribution networks
Authors: Zarghami Seyed Ashkan , Gunawan Indra , Schultmann Frank
Published: May 2019

Purpose

The increased complexity of water distribution networks (WDNs) emphasizes the importance of studying the relationship between topology and vulnerability of these networks. However, the few existing studies on this subject measure the vulnerability at a specific location and ignore to quantify the vulnerability as a whole. The purpose of this paper is to fill this gap by extending the topological vulnerability analysis further to the global level.

Design/methodology/approach

This paper introduces a two-step procedure. In the first step, this work evaluates the degree of influence of a node by employing graph theory quantities. In the second step, information entropy is used as a tool to quantify the global vulnerability of WDNs.

Findings

The vulnerability analysis results showed that a network with uniformly distributed centrality values exhibits a lower drop in performance in the case of partial failure of its components and therefore is less vulnerable. In other words, the failure of a highly central node leads to a significant loss of performance in the network.

Practical implications

The vulnerability analysis method, developed in this work, provides a decision support tool to implement a cost-effective maintenance strategy, which relies on identifying and prioritizing the vulnerabilities, thereby reducing expenditures on maintenance activities.

Originality/value

By situating the research in the entropy theory context, for the first time, this paper demonstrates how heterogeneity and homogeneity of centrality values measured by the information entropy can be interpreted in terms of the network vulnerability.
A global taxonomic review and analysis of the development of BIM research between 2006 and 2017
Authors: Saka Abdullahi Babatunde , Chan Daniel W.M.
Published: May 2019

Purpose

This paper aims to review the status of development of building information modelling (BIM), its trends and themes across the six continents of the world.

Design/methodology/approach

A total of 914 journal articles sought from the search engine of Web of Science (WOS) based on the country/region option of the WOS to group them into continents. A best-fit approach was then applied in selecting the suitable software programmes for the scientometric analysis and comparisons and deductions were made.

Findings

The findings revealed that there are differences in the development of BIM across the six continents of the world. South America and Africa are lagging in the BIM research and Australia and Asia are growing, whilst Europe and North America are ahead. In addition, there exist differences in the research themes and trends in these continents as against the single view presented in extant studies.

Originality/value

This study introduced a new approach to carry out a comparative and taxonomic review and has provided both academic researchers and industrial practitioners with a clear status of development of BIM research and the trend across the six continents of the world.
Utilising trade unions in business continuity management to create resilience
Authors: Ferguson Cliff
Published: May 2019

Purpose

Trade unions are the political arm of the working class, economically active masses, whilst industrial action is a demonstration of the will to reach their objectives. However, the crippling of systems through such contradicts business continuity. Yet, the opposite is true for a natural disaster that traumatises the union member and has a direct impact on their well-being. Inculcating a service continuity and resilience in government, with trade unions as majority stakeholders, may be a challenge. Moreover, it is further complicated by the African perspective, which will become prevalent in the author’s deliberations, as the trade union landscape is open to revolutionary Marxism, Socialism and Capitalistic precepts and concepts. Testing the problem and solutions with the period model produces evidence that purports a future praxis for business continuity management (BCM) that involves trade union representatives and their members. Ultimately, trade unions, cumbersome as they may seem, have much to offer as far as human resources, mass membership, knowledge and skill are concerned. The paper aims to discuss these issues.

Design/methodology/approach

An action learning approach linked to the period model to answer five research questions, namely: What is the actual modus operandi of trade unions with regard to business continuity and resilience?; What is the actual interest of union representatives in the understanding and implementation of BCM and resilience standards and concepts?; What would be required to utilise trade union platforms for the purposes of BC induction and awareness?; How will BCM certification for trade union stewards affect or impact on their industrial actions or campaigns?; How can the BCM fora develop a theory and possible praxis, to involve trade unions as part of the business continuity and resilience programme of an organisation?

Findings

The findings are as follows: the period model works as an agent of action learning. The likelihood of trade unions to participate in business continuity outside of labour action is commendable. Trade union representatives are keen on being certified as BCM practitioners. BCPs are inclined to fail with industrial action when involving trade union representatives. The BCM Policy and ISO 22301 standards bring about a good understanding of the roles of BC practitioners and union representatives in a crisis period.

Research limitations/implications

Research was limited to the pilot site, i.e. The Government Pensions Administration Agency – South Africa.

Originality/value

The paper brings about a new dimension to a business continuity programme, where the trade unions are no longer an interested party but rather they become active members of a business continuity team.
Free element method and its application in CFD
Authors: Gao X.W. , Liu Huayu , Cui Miao , Yang Kai , Peng Haifeng
Published: May 2019

Purpose

The purpose of this paper is to propose a new strong-form numerical method, called the free element method, for solving general boundary value problems governed by partial differential equations. The main idea of the method is to use a locally formed element for each point to set up the system of equations. The proposed method is used to solve the fluid mechanics problems.

Design/methodology/approach

The proposed free element method adopts the isoparametric elements as used in the finite element method (FEM) to represent the variation of coordinates and physical variables and collocates equations node-by-node based on the newly derived element differential formulations by the authors. The distinct feature of the method is that only one independently formed individual element is used at each point. The final system of equations is directly formed by collocating the governing equations at internal points and the boundary conditions at boundary points. The method can effectively capture phenomena of sharply jumped variables and discontinuities (e.g. the shock waves).

Findings

a) A new numerical method called the FEM is proposed; b) the proposed method is used to solve the compressible fluid mechanics problems for the first time, in which the shock wave can be naturally captured; and c) the method can directly set up the system of equations from the governing equations.

Originality/value

This paper presents a completely new numerical method for solving compressible fluid mechanics problems, which has not been submitted anywhere else for publication.
Social representations of marketing work: advertising workers and social media
Authors: Cluley Robert , Green William
Published: May 2019

Purpose

Informed by social representation theory, the study aims to explore how marketing workers represent their activities on social media.

Design/methodology/approach

A naturalistic data set of 17,553 messages posted on Twitter by advertising workers was collected. A sample of over 1,000 unique messages from this data set, incorporating all external links and images, was analysed inductively using structured thematic analysis.

Findings

Advertising workers represent marketing work as a series of fun yet constrained activities involving relationships with clients and colleagues. They engage in cognitive polyphasia by evaluating these productive differences in both a positive and negative light.

Research limitations/implications

The study marks a novel use of social representation theory and innovative social media analysis. Further research should explore these relations in greater depth by considering the networks that marketing workers create on social media and establish how, when and why marketing workers turn to social media in their everyday activities.

Practical implications

Marketing workers choose to represent aspects of their work to one another, using social media. Marketing managers should support such activities and consider social media as a way to understand the lives and experiences of marketing workers.

Originality/value

Marketing researchers have embraced digital media as a route to understanding consumers. This study demonstrates the value of analysing digital media to develop an understanding of marketing work. It sheds new light on the ways marketing workers create social relationships and enables marketing managers to understand and observe the social aspects of effective marketing.
Legislative framework for implementing recognition of prior learning
Authors: Hlongwane Ike
Published: May 2019

Purpose

The purpose of this paper is to identify and highlight the key constructs of an enabling policy environment and their probable impact on development and implementation of recognition of prior learning (RPL) process in higher education and training in South Africa with reference to library and information science (LIS) field.

Design/methodology/approach

The study adopted quantitative methods, and utilised questionnaires and document analysis to collect data. The study used a combination of quantitative and qualitative methods to collect data from all the ten LIS schools in the South African higher education and training landscape. The questionnaire was used as the main data collection tool to collect quantitative data through a survey research design. In addition, the researcher employed content analysis to analyse qualitative data collected from institutional RPL policy documents.

Findings

The study found that the LIS schools have aligned most of their institutional RPL policies and procedures with South African Qualifications Authority’s national RPL policy (2013). However, in terms of the institutional RPL policy environment, the study found that there was a low level of compliance regarding certain aspects of the policy environment among LIS schools despite their express explicit commitment to the principles of equity of access and redress.

Research limitations/implications

In-depth interviews were not conducted to ascertain the reasons for low level of compliance regarding certain aspects of the RPL policy.

Practical implications

This study is valuable for higher education institutions, policy and governance, government and other stakeholders to assess the level of compliance to legislative and regulatory framework in RPL implementation in higher education and training in South Africa. In addition, the study was important for LIS schools in particular as RPL can be used as a tool to open access and increase participation in learning programmes to counteract low level of student enrolments in this field.

Originality/value

There is very little published concerning compliance to legislative framework RPL implementation in higher education and training. Furthermore, most published work relate to RPL implementation in higher education and training in general. The paper describes compliance to legislative framework to RPL implementation in higher education and training in South Africa with special reference to LIS field.
A recommended closed-loop assessment of learning outcomes process for hospitality programs
Authors: Reich Allen Z. , Collins Galen R. , DeFranco Agnes L. , Pieper Suzanne L.
Published: May 2019

Purpose

Because of the increasingly higher expectations of accrediting organizations, calls for greater accountability from state governments and students’ demand for an education that prepares them for a career, most hospitality programs are now required to have an effective assessment of learning outcomes process. The increasing popularity of the assessment of learning outcomes process is viewed as highly positive because it can be considered as best-practices in higher education. The paper aims to discuss this issue.

Design/methodology/approach

This is Part 2 of a two-part article that provides an overview of the justifications for implementing an assessment of learning outcomes process, the steps that were developed by two hospitality programs, and the experiences of the two programs during implementation.

Findings

The steps in a closed-loop assessment of learning outcomes process are relatively detailed; however, because of changes in expectations of stakeholders and the requirements of accreditors, they are now mandatory for most hospitality programs. Therefore, the choice is not whether to implement them, but when. From a competitive standpoint, it is to the program’s advantage to begin as soon as possible. Another factor to consider is that the implementation of a closed-loop assessment of learning outcomes process will take several years to complete.

Originality/value

This paper is presenting a critical view of one of, if not the most important concepts in higher education, the closed-loop assessment of learning outcomes process. Hopefully, the information on the process that is provided and the experiences of the two programs can shorten the learning curve for other hospitality programs.
Physique differences and psychophysiological response under clothing pressure using waist belt
Authors: Uemae Mayumi , Uemae Tomohiro , Kamijo Masayoshi
Published: May 2019

Purpose

The purpose of this paper is to examine the physique difference and psychophysiological response under clothing pressure by a waist belt.

Design/methodology/approach

The influences of clothing pressure on physiological and psychological responses were evaluated by the following measurements: functional near-infrared spectroscopy, electrocardiogram and sensory evaluation. The authors investigated the correlation between the anthropometric data and psychophysiological response data.

Findings

There were significant correlations between body fat and physiological responses. It was suggested that differences in body fat affect changes in cerebral hemodynamics and heart rate due to clothing pressure. It is inferred that the participants having lower body fat reacted more sensitively to the compression stimulus, while those having higher body fat were more tolerant of physiological reactions to compression stimulus.

Originality/value

This paper has presented the necessity of clothing comfort evaluation considering individual differences in physique due to body fat.
GCG, financial architecture on stock return, financial performance and corporate value
Authors: Suhadak Suhadak , Mangesti Rahayu Sri , Handayani Siti Ragil
Published: May 2019

Purpose

The purpose of this paper is to observe and analyze the influence of good corporate governance (GCG) and financial architecture on stock returns and financial performance and its implication for corporate value.

Design/methodology/approach

The data were analyzed using generalized structured component analysis. The unit of analysis for this research was LQ45 listed companies at the Indonesian Stock Exchange, taking data from the Indonesia Capital Market Directory (ICMD), and the annual reports and financial reports of these companies. The population researched was as many as 84 companies. For the sample, LQ45 companies with annual reports, financial reports and long-standing, continuous ICMD membership were examined using “purposive sampling.” The research sample was about 22 companies assessed over the course of five years (i.e. 110 samples).

Findings

First, GCG has a significant and negative relationship to stock returns; second, financial architecture has a significant and positive relationship to stock returns, financial performance and corporate value; third, stock returns have a significant and positive relationship to financial performance and corporate value; and fourth, financial performance has a significant and positive relationship to stock returns and corporate value.

Originality/value

The originality of this research is to be found in its examination and analysis of relationships between stock returns and financial performance, which was discovered to be reciprocal, namely, the relationship between the variables occurring affected each other (causality alternating with turning), whereas in previous studies the relationship between variables was unidirectional. Besides the research undertaken before, an analysis was made to understand the influence of GCG on stock returns, corporate value and financial performance. There are differences in the results between studies that support the conjecture that financial architecture has a significant positive effect on financial performance and corporate value, and also that financial architecture has a significant positive effect on financial performance and corporate value. Given those existing differences, this study reexamines the effect of financial architecture on financial performance and corporate value.
Piston-ring performance: limitations from cavitation and friction
Authors: Dellis Polychronis Spyridon
Published: May 2019

Purpose

Cavitation in piston-ring lubrication is studied as part of the performance of piston-ring assemblies. Cavitation degrades performance in engineering applications and its effect is that it alters the oil film pressure, generated at the converging-diverging wedge of the interface. Studies tried to shed light to the phenomenon of cavitation and compare it with cavities that have been identified in bearings. The paper aims to discuss this issue.

Design/methodology/approach

Lubricant formulations were used for parametric study of oil film thickness (OFT) and friction providing the OFT throughout the stroke and LIF for OFT point measurements. Lubricant formulation affects cavitation appearance and behaviour when fully developed.

Findings

Cavitation affects the ring load carrying capacity. Different forms of cavitation were identified and their shape and size (length and width) is dictated from reciprocating speed and viscosity of the lubricant. A clear picture is given from both techniques and friction results give quantifiable data in terms of the effect in wear and cavitation, depending on the lubricant properties.

Research limitations/implications

Engine results are limited due to manufacturing difficulties of visualisation windows and oil starvation. Therefore, full stroke length sized windows were not an option and motoring tests were implemented due to materials limitations (adhesive and quartz windows). Lubricant manufacturer has to give data regarding the chemistry of the lubricants.

Originality/value

The contribution of cavitation in piston-ring lubrication OFT, friction measurements and lubricant parameters that try to shed light to the different forms of cavitation. A link between viscosity, cavitation, shear thinning properties, OFT and friction is given.
Understanding the expression of grievances in the Arabic Twitter-sphere using machine learning
Authors: Al-Saggaf Yeslam , Davies Amanda
Published: May 2019

Purpose

The purpose of this paper is to discuss the design, application and findings of a case study in which the application of a machine learning algorithm is utilised to identify the grievances in Twitter in an Arabian context.

Design/methodology/approach

To understand the characteristics of the Twitter users who expressed the identified grievances, data mining techniques and social network analysis were utilised. The study extracted a total of 23,363 tweets and these were stored as a data set. The machine learning algorithm applied to this data set was followed by utilising a data mining process to explore the characteristics of the Twitter feed users. The network of the users was mapped and the individual level of interactivity and network density were calculated.

Findings

The machine learning algorithm revealed 12 themes all of which were underpinned by the coalition of Arab countries blockade of Qatar. The data mining analysis revealed that the tweets could be clustered in three clusters, the main cluster included users with a large number of followers and friends but who did not mention other users in their tweets. The social network analysis revealed that whilst a large proportion of users engaged in direct messages with others, the network ties between them were not registered as strong.

Practical implications

Borum (2011) notes that invoking grievances is the first step in the radicalisation process. It is hoped that by understanding these grievances, the study will shed light on what radical groups could invoke to win the sympathy of aggrieved people.

Originality/value

In combination, the machine learning algorithm offered insights into the grievances expressed within the tweets in an Arabian context. The data mining and the social network analyses revealed the characteristics of the Twitter users highlighting identifying and managing early intervention of radicalisation.
Do Australian media apply recommendations when covering a suicide prevention campaign?
Authors: Thienel Renate , Bryant Marc , Hazel Gavin , Skehan Jaelea , Tynan Ross
Published: May 2019

Purpose

Media reporting and portrayals of mental illness and suicide can play an important role in shaping and reinforcing community attitudes and perceptions. Depending on the content, a report about suicide can have either a negative (Werther-) or a positive (Papageno-) effect. Evidence-informed recommendations for the reporting of suicide in Australia are provided under the Mindframe initiative. The purpose of this paper is to assess the application of these recommendations in broadcasts associated with one of the largest national campaigns to promote suicide prevention, the R U OK? Day, a yearly campaign of the Australian suicide prevention charity R U OK?

Design/methodology/approach

The sample consisted of 112 (32 TV, 80 radio) Australian broadcasts discussing the R U OK? Day suicide prevention campaign during the month preceding the 2015 campaign and on the national R U OK? Day itself. Broadcasts were coded for medium (TV or radio), content (suicide focus, mental illness focus or both) and consistency with Mindframe recommendations.

Findings

Over 97 per cent of broadcasts used language consistent with Mindframe recommendations. None of the broadcasts used images that negatively portrayed mental illness or suicide; there were no instances of using mental illness to describe a person’s behaviour; and no sensationalizing or glamorising terminology was used in the broadcasts. However, less than 40 per cent of the broadcasts included help-seeking information (e.g. helplines) and some of the broadcasts used negative or outdated terminology (e.g. “commit” suicide; “suffering” from mental illness).

Originality/value

The present study is the first to examine consistency with reporting recommendations around a national suicide prevention campaign (R U OK? Day). The results can steer improvements in current reporting and inform strategies to optimise future reporting.
Reducing perceived vulnerability to increase utilization of nonprofit services
Authors: Tanner Emily C. , Su Lixun
Published: May 2019

Purpose

The purpose of this study is to understand how perceived vulnerability reduces consumers’ willingness to utilize services offered by nonprofit organizations (NPOs).

Design/methodology/approach

Three online surveys were conducted across two research contexts to test the proposed model. Hayes’ PROCESS was used to analyze the data.

Findings

Perceived vulnerability decreases the perception of relational benefits, which in turn decrease consumers’ commitment to NPOs. Reduced commitment lessens consumers’ willingness to cooperate and acquiesce to organizations’ recommendations. Risk aversion and cognitive ability mediate the relationship between perceived vulnerability and perceived relational benefits.

Research limitations/implications

The findings uncover mechanisms through which perceived vulnerability influences perceived relational benefits, contributing to the understanding of behaviors of consumers that perceive vulnerable. This paper does not manipulate consumers’ perceived vulnerability but only measures their perceived vulnerability, limiting the explanatory power of causal relationships between perceived vulnerability and perceived relational benefits.

Practical implications

This study can provide some insight for NPOs about how to better serve their target population. To increase willingness to utilize service offerings, NPOs should decrease their perceived risks of new services.

Originality/value

This paper clarifies why consumers that perceive vulnerability are not willing to deploy the NPOs’ services which could improve their situation by demonstrating that cognitive ability and risk aversion mediate the relationship between perceived vulnerability and perceived relational benefits.
Establishing a maker culture beyond the makerspace
Authors: Beavers Karen , Cady Jennifer Esteron , Jiang Amy , McCoy Liberty
Published: May 2019

Purpose

The purpose of this paper is to describe the process of fostering a maker culture in a liberal arts university. It explores the impact of making on student learning and engagement, as well as the role of the library’s maker program.

Design/methodology/approach

This paper is a case study that presents the tools and activities used in an academic library’s maker program. Structured interviews were conducted with faculty, staff and students to review the program and maker culture influence on campus.

Findings

Findings highlight the library’s role in supporting maker culture on a liberal arts campus and address ways making contributes to student engagement and learning. Interviewees also recommend strategies to increase awareness and market the library’s maker program to engage a wider community.

Originality/value

Though there are many articles written about the maker movement and libraries, this study contributes to the growing body of research on makerspaces in higher education, with particular focus on a library at a liberal arts university.
Social enterprises in quasi-markets: exploring the critical knowledge gaps
Authors: Mason Chris , Roy Michael J. , Carey Gemma
Published: May 2019

Purpose

This paper aims to explore how social enterprises are treated in scholarly research on quasi-markets. In so doing, the paper aims to show that a number of critical knowledge gaps persist which require deeper engagement from researchers, practitioners and policymakers alike.

Design/methodology/approach

This study adopts a conceptual analysis of the existing literature concerning social enterprises and quasi-markets.

Findings

The paper finds that there are four main knowledge gaps in this area. First, there are moral dilemmas created by boundary shifts, arising from the development of quasi-markets. Second, the phenomenon of “tactical mimicry” (Day and Teasdale 2016) represents a key theoretical platform not yet fully explored. Third, the lack of clear, comparative assessments of social enterprises across quasi-markets, and other types of service providers is also apparent despite offering a significant methodological opportunity for scholars. Fourth, there is the issue of how social enterprises engage in, and resource the operational functions that will support their management of conflicting logics, especially rigorous impact measurement.

Originality/value

This paper uses a synthesis of key social enterprise and quasi-market studies to extend current debate in this area, which tends to be diffused and complex. By focussing on critical knowledge gaps, the paper contributes a meta-level appraisal of the key areas for future research, providing a focussed agenda for scholars to target their efforts in growing this important body of knowledge.
Outline Shape Analysis on the Trochlear Constriction and Olecranon Fossa of the Humerus: Insights for Sex Estimation and a New Computational Tool,
Authors: Ammer Saskia , d'Oliveira Coelho João , Cunha Eugénia Maria
Published: May 2019

Sex estimation through visual analysis of the distal humerus can contribute to establishing the biological profile of an unidentified skeletal individual. Using statistical shape modeling, the trochlear constriction open curves and olecranon fossa closed outlines of 151 humeri were digitized and analyzed. The shape configurations exhibited strikingly different degrees of sexual dimorphism when evaluated using linear discriminant analysis with leave‐one‐out cross‐validation. The trochlear constriction performed poorly, correctly classifying 63.6% of the individuals. However, the olecranon fossa showed high sexual dimorphism, presenting a 94.0% accuracy. A simpler model using only two principal components was also generated. While the accuracy is slightly inferior (88.1%), it has the advantage of being constrained to bidimensional components that were translated into morphoscopic variables within a simulator interface. This allowed us to implement the method through a web application that does not require users to be trained in landmark digitization or have knowledge of geometric morphometrics.
EM telemetry assessment for horizontal drilling in part of the Tarim basin through numerical simulation
Authors: Fayemi Olalekan , Di Qingyun , Zhen Qihui
Published: May 2019

Electromagnetic telemetry is bi‐directional transmission of borehole data for effective drilling, especially in unconventional wells. In this study, numerical simulations was used to investigate the possibility of applying EM telemetry for measurement while drilling (MWD) in an ultra‐deep borehole in the Tahe region of the Tarim basin, using the drill string as an antenna excited as a gaped dipole source to quantify spatial variations of the electromagnetic field from subsurface to the surface. Results confirm that the distribution of the electric field along the drill string is sensitive to vertical variations of electric conductivity in the host rock. The simulated results show a high attenuation within the conductive formations, thereby limiting the effectiveness of EM telemetry in data transfer to the surface. In addition, the changes in thickness and resistivity of the target region affects the amplitude of the desired response.
Zircon Growth During Subduction and Exhumation Metamorphism of Mafic Rocks, Aktyuz terrain, North Tiahshan, Kyrgyzstan
Authors: DONG Hanwen , XU Zhiqin , YI Zhiyu , MA Zeliang
Published: May 2019

The Yardoi dome is located in the eastern end of the north Himalayan domes (NHD), distributed in northwest‐southeast direction. Previous mapping and analytical studies established the distribution of three lithologic–tectonic units, positions of the upper detachment fault and the lower detachment fault. The lower detachment fault is a strongly deformed top‐NW shear zone with ∼800 m thick, termed as the Yardoi detachment fault (YDF). LA‐ICP‐MS zircon U–Pb dating yielded a crystallization age of 19.57 ± 0.23 Ma ∼15.5 ± 0.11 Ma for the leucogranite dyke swarm, which indicates that the ductile motion along the YDF began at ca.20 Ma. Muscovite from the three studied samples yielded 40Ar/39Ar ages between 14.05 ± 0.2 Ma and 13.2 ± 0.2 Ma. The biotite from the garnet‐bearing two‐mica gneiss have 40Ar‐39Ar age of 13.15 ± 0.2 Ma. These results suggest that the exhumation led to cooling through the 370°C Ar closure temperature in muscovite at ∼14 Ma to the 335°C Ar closure temperature in bioitte at ∼13 Ma. Thermochronological data indicates that ductitle motion along the YDF continued until at least 13 Ma. We correlate the YDF to the South Tibet detachment system (STDS) on the basis of lithological, metamorphic, structural, and chronological criteria and consider the YDF, a top‐to‐northwest shear zone, may represent the northern extension of the STDS. Comparing the Yardoi dome to the other domes in the NHD, the cooling ages show a clear diachronism and they are progressively younger from the west to east Himalaya.
The origin and emplacement of the Lajishankou ophiolite complex in the South Qilian belt: evidences from geological mapping
Authors: FU Changlei , YAN Zhen , BUCHMAN Solomon , AITCHISON Jonathan , NIU Manlan
Published: May 2019

Many ophiolite complexes like those of Oman and New Caledonia represent fragments of ancient oceanic crust and upper mantle generated at supra‐subduction zone environments and have been obducted onto the adjacent rifted continental margin together with the accretionary complexes and intra‐oceanic arcs. The Lajishan ophiolite complexes in the Qilian orogenic belt along the NE edge of the Tibet‐Qinghai Plateau are one of several ophiolites situated to the south of the Central Qilian block. Our geological mapping and petrological investigations suggest that the Lajishankou ophiolite complex consists of serpentinite, wehrlite, pyroxenite, gabbro, dolerite, and pillow and massive basalts that occur in a series of elongate fault‐bounded slices. An accretionary complex composed mainly of basalt, radiolarian chert, sandstone, mudstone, and mélange lies structurally beneath the ophiolite complex. The Lajishankou ophiolite complex and accretionary complex were emplaced onto the Qingshipo Formation of the Central Qilian block which shows features typical of turbidites deposited in a deep‐water environment of passive continental margin. Our geochemical and geochronological studies indicate that the mafic rocks in the Lajishankou ophiolite complex can be categorized into three distinct groups: massive island arc tholeiites, 509 Ma back‐arc dolerite dykes, and 491 Ma pillow basaltic and dolerite slices that are of seamount origin in a back‐arc basin. The ophiolite and accretionary complex constitute a Cambrian‐early Ordovician trench‐arc system within the South Qilian belt during the early Paleozoic southward subduction of the South Qilian Ocean prior to Early Ordovician obduction of this system onto the Central Qilian block.
Kalaymyo Peridotite Massif in the Indo‐Myanmar Ranges (western Myanmar): Its Mineralogy, Geochemistry and Tectonic Implications
Authors: NIU Xiaolu , LIU Fei , YANG Jingsui , DILEK Yildirim
Published: May 2019

Mesozoic ophiolites crop out discontinuously in the Indo‐Myanmar Ranges in NE India and Myanmar, and represent the remnants of the Neotethyan oceanic lithosphere. These ophiolites in the Indo‐Myanmar Ranges are the southern continuation of the Neotethyan ophiolites occurring along the Yarlung Zangbo Suture Zone in southern Tibet farther northwes, as indicated by their coeval crystallization ages and geochemical compositions. The Kalaymyo ophiolite is located in the central part of the Indo‐Myanmar Ranges (Myanmar). The Kalaymyo ophiolite are composed of olivine (Fo = 89.8–90.5), orthopyroxene (En86‐91Wo1‐4Fs8‐10; Mg#=89.6–91.9), clinopyroxene (En46‐49Wo47‐50Fs3‐5; Mg# = 90.9–93.6) and spinel (Mg# = 67.1–78.9; Cr# = 13.5–31.5), and have relatively homogeneous whole‐rock compositions with Mg# of 90.1–90.8 and SiO2 (41.5–43.65 wt.%), Al2O3 (1.66–2.66 wt.%) and CaO (1.45–2.67 wt.%) contents. They display Light Rare Earth Element (LREE)‐depleted chondrite‐normalized REE patterns and show a slight enrichment from Pr to La. The Kalaymyo peridotites are characterized by Pd‐enriched chondrite‐normalized PGE patterns with superchondritic (Pd/Ir)CN ratios (1.15–2.36). Their calculated oxygen fugacities range between QFM–0.57 and QFM+0.90. These features collectively suggest that the Kalaymyo peridotites represent residual upper mantle rocks after low to moderate degrees (5–15%) of partial melting at a mid‐ocean‐ridge environment. The observed enrichment in LREE and Pd was a result of their reactions with enriched MORB‐like melts, percolating through these already depleted, residual peridotites. The Kalaymyo and other ophiolites in the Indo‐Myanmar Ranges hence represent mid‐ocean ridge–type Tethyan oceanic lithosphere derived from a downgoing plate and accreted into a westward migrating subduction–accretion system along the eastern margin of India.
Unusual Uranium‐rich Fluid Flow During Exhumation of Deeply Subducted Continental Crust
Authors: SHENG Yingming
Published: May 2019

In‐situ SIMS analyses of O and U‐Pb isotopes were carried out for zircons from a quartz vein hosted by ultrahigh‐pressure metagranite (UHP) in the Dabie orogen. The results are integrated to decipher the property of unusual U‐rich aqueous fluids and their effects on both metamorphic and magmatic zircons during exhumation of the UHP metagranite. In CL images, most zircon grains show distinct core‐rim structures. Relict cores are bright and exhibit oscillatory or patchy zonation, giving Neoproterozoic upper‐intercept ages of 795 ± 26 Ma. Newly grown rims are dark and exhibit no zoning, yielding Triassic concordant ages of 215 ± 5 Ma. The cores give Th contents of 59 to 463 ppm and U contents of 98 to 558 ppm, with Th/U ratios of 0.263 to 1.423. The rims yield reduced Th contents of 11 to 124 ppm but significantly elevated U contents of 1051 to 3531 ppm, with Th/U ratios of 0.010 to 0.035. Comparison with the cores of magmatic origin, the unusual enrichment in U but depletion in Th in the rims of metamorphic origin are interpreted as zircon growth from Cl‐rich oxidized vein‐forming aqueous fluids that were produced by dehydration reactions of the wallrock during continental exhumation. The cores have variably positive δ18O values with concordant or discordant Neoproterozoic U‐Pb ages, suggesting their solid‐state modification of both O and U‐Pb isotopes through interaction with the fluids. The rims yield negative δ18O values, indicating their growth from the negative δ18O fluids. Taken together, the proposed Cl‐rich oxidized negative‐δ18O vein‐forming aqueous fluids have such an ability to not only cause variable metamorphic recrystallization in the relict magmatic zircons but also produce dramatic fractionation of U over Th in the metamorphic zircons during quartz veining, and potentially impact on the overlain metasomatite in the mantle wedge.
Diamond‐bearing Occurrences of the Ural‐Timan Fold Belt (Russia): The Result of Ultra‐deep Subduction?
Authors: SHMELEV Vladimir
Published: May 2019

Large deposits of diamonds are associated mainly with kimberlites (and related rocks) of the cratons, but they are also known in the folded belts surrounding them. As an example is the Baltica craton and the surrounding its the Ural‐Timan (UT) folded belt. With the first object are associated diamonds of the Arkhangelsk (kimberlites and placers) provinces, and with the second one ‐ mostly placer deposits of the UT province, the probable source of which are also kimberlites. The structural position, composition and age of the potentially diamond‐bearing complexes of the Urals and Timan make it possible to propose a new petrological‐geodynamic interpretation of their formation. According to this model, during the Vendian‐Cambrian subduction of the Pechora Ocean crust, several different depth complexes have been formed, being changed in the western direction. At a shallow depth level the oceanic crust subduction is accompanied only by fluid processing, without the magmatism participation. As a result, this process leads to the formation of fluidizate‐explosive rocks of the Sertynya complex, which marks the outlet of the ancient subduction zone into the surface. At a moderately deep (up to 100–150 km) level melts are being produced, the derivatives of which are not diamond‐bearing depleted kimberlites of the Khartes (V‐Cm) complex. Apparently by the beginning of the Ordovician the active subduction of the Pechora Ocean stops. It occurs an opening of a new Ural paleoocean, and the earlier submerged the oceanic slab continues moving under the Baltica craton. At a deep (above 150 km) level the slab interaction with the mantle produces typical kimberlite magmas (from the Ordovician to the Middle Devonian) transporting diamonds to the surface of the Ural‐Timan province proper.
High‐ and low‐Cr chromitite in a Tibetan Ophiolite: Evolution from Mature Subduction System to Incipient Forearc in the Neo‐Tethyan Ocean
Authors: XIONG Qing , ZHENG Jianping , GRIFFIN William , O'REILLY Suzanne
Published: May 2019

The microstructures, major‐ and trace‐element compositions of minerals and electron backscattered diffraction (EBSD) maps of high‐ and low‐Cr# [spinel Cr# = Cr3+/(Cr3++Al3+)] chromitites and dunites from the Zedang ophiolite in the Yarlung Zangbo Suture (South Tibet) have been used to reveal their genesis and the related geodynamic processes in the Neo‐Tethyan Ocean. The high‐Cr# (0.77‐0.80) chromitites (with or without diopside exsolution) have chromite compositions consistent with initial crystallization by interaction between boninitic magmas, harzburgite and reaction‐produced magmas in a shallow, mature mantle wedge. Some high‐Cr# chromitites show crystal‐plastic deformation and grain growth on previous chromite relics that have exsolved needles of diopside. These features are similar to those of the Luobusa high‐Cr# chromitites, possibly recycled from the deep upper mantle in a mature subduction system. In contrast, mineralogical, chemical and EBSD features of the Zedang low‐Cr# (0.49‐0.67) chromitites and dunites and the silicate inclusions in chromite indicate that they formed by rapid interaction between forearc basaltic magmas (MORB‐like but with rare subduction input) and the Zedang harzburgites in a dynamically extended, incipient forearc lithosphere. The evidence implies that the high‐Cr# chromitites were produced or emplaced in an earlier mature arc (possibly Jurassic), while the low‐Cr# associations formed in an incipient forearc during the initiation of a new episode of Neo‐Tethyan subduction at ∼130‐120 Ma. This two‐episode subduction model can provide a new explanation for the coexistence of high‐ and low‐Cr# chromitites in the same volume of ophiolitic mantle.
Iron Isotopic Compositions of Forearc Mantle Peridotites Constrained by Ophiolites from the North Qilian Orogen, Northern Tibet
Authors: ZHANG Long , SUN Weidong , AN Yajun , LIU Fang , ZHANG Zhaofeng
Published: May 2019

Previous studies on iron isotope compositions of subduction zone magmas have revealed significant and complex variations that have great bearings on petrogenetic processes in the mantle wedge, e.g., partial melting, fluid metasomatism and redox state. However, interpretations for the fractionations are highly debatable and lack direct constraints from mantle wedge peridotites. This study presents iron isotope compositions for whole rocks and mineral separates in fresh forearc peridotites from the Yushigou ophiolite, North Qilian orogen in northern Tibet. Major and trace element compositions of whole rock and mineral indicate that the peridotites are highly depleted forearc peridotites overprinted by melt metasomatism, in contrast to the long‐holding opinion that the peridotites are derived from mid‐oceanic ridges. The minerals fall on a line with a slope of ∼1 on the plot of δ56Fe vs. δ56Fe, indicating isotope equilibrium between minerals. δ56Fe fractionation between olivine and orthopyroxene is within the range of 0∼0.05, while fractionation between olivine and spinel is about 0.05∼0.10. The fractionation trend between olivine and spinel is opposite to previous theoretical and experimental constraints, which may be due to substantial Cr substitution into the spinel. This indicates that negative correlations between spinel Cr#, fO2 and spinel δ56Fe in previous studies are probably a reflection of gradual Cr enrichment in spinel during melt extraction, and spinel δ56Fe values are not a proxy for oxygen fugacity. Whole rock δ56Fe values are well correlated with mineral δ56Fe values, varying from overlapping with depleted mantle to slightly lower than depleted mantle. Therefore, variations in iron isotope compositions of subduction zone magmas are probably due to combined effect of source heterogeneity and partial melting fractionation.