bluuebunny/crossref_metadata_2025 huggingface dataset:
Repeated co-option of a conserved gene regulatory module underpins the evolution of the crustacean carapace, insect wings and other flat outgrowths
Authors: Shiga Yasuhiro , Kato Yasuhiko , Aragane-Nomura Yuko , Haraguchi Takayuki , Saridaki Theodora , Watanabe Hajime , Iguchi Taisen , Yamagata Hideo , Averof Michalis
Published: July 2017

Summary statement

The genesvestigial, scallopedandwinglesscomprise a conserved regulatory module that was co-opted repeatedly for the evolution of flat structures, such as insect wings, and crustacean carapace, tergites and coxal plates.

How novelties arise is a key question in evolutionary developmental biology. The crustacean carapace is a novelty that evolved in the early Cambrian. In an extant crustacean,Daphnia magna, the carapace grows from the body wall as a double-layered sheet with a specialized margin. We show that the growing margin of this carapace expressesvestigial, scallopedandwingless, genes that are known to play key roles in regulating growth at the insect wing margin. RNAi-mediated knockdown ofscallopedandwinglessimpair carapace development, indicating that carapace and wing might share a common mechanism for margin outgrowth. However, carapace and wings arise in different parts of the body and their margins have different orientations, arguing that these structures have independent evolutionary origins. We show thatscallopedis also expressed at the margin of unrelated flat outgrowths (tergites and coxal plates) in the distantly related crustaceanParhyale hawaiensis. Based on these observations, we propose that thevestigial-scalloped-winglessgene module has a common role in the margin of diverse flat structures, originating before the divergence of major crustacean lineages and the emergence of insects. Repeated co-option of this module occurred independently in the carapace, wing and other flat outgrowths, underpinning the evolution of distinct novelties in different arthropod lineages.
Associations between polygenic liability for schizophrenia and level of psychosis and mood-incongruence in bipolar disorder
Authors: Allardyce Judith , Leonenko Ganna , Hamshere Marian , Pardiñas Antonio F. , Forty Liz , Knott Sarah , Smith Katherine-Gordon , Porteus David J. , Haywood Caroline , Di Florio Arianna , Jones Lisa , McIntosh Andrew M. , Owen Michael J. , Holmans Peter , Walters James T.R. , Craddock Nicholas , Jones Ian , O’Donovan Michael C. , Escott-Price Valentina
Published: July 2017

Importance

Bipolar disorder (BD) overlaps schizophrenia in its clinical presentation and genetic liability. Alternative approaches to patient stratification beyond current diagnostic categories are needed to understand the underlying disease processes/mechanisms.

Objectives

To investigate the relationship between common-variant liability for schizophrenia, indexed by polygenic risk scores (PRS) and psychotic presentations of BD, using clinical descriptions which consider both occurrence and level of mood-incongruent psychotic features.

Design

Case-control design: using multinomial logistic regression, to estimate differential associations of PRS across categories of cases and controls.

Settings & Participants

4399 BDcases, mean [sd] age-at-interview 46[12] years, of which 2966 were woman (67%) from the BD Research Network (BDRN) were included in the final analyses, with data for 4976 schizophrenia cases and 9012 controls from the Type-1 diabetes genetics consortium and Generation Scotland included for comparison.

Exposure

Standardised PRS, calculated using alleles with an association p-value threshold < 0.05 in the second Psychiatric Genomics Consortium genome-wide association study of schizophrenia, adjusted for the first 10 population principal components and genotyping-platform.

Main outcome measure

Multinomial logit models estimated PRS associations with BD stratified by (1) Research Diagnostic Criteria (RDC) BD subtypes (2) Lifetime occurrence of psychosis.(3) Lifetime mood-incongruent psychotic features and (4) ordinal logistic regression examined PRS associations across levels of mood-incongruence. Ratings were derived from the Schedule for Clinical Assessment in Neuropsychiatry interview (SCAN) and the Bipolar Affective Disorder Dimension Scale (BADDS).

Results

Across clinical phenotypes, there was an exposure-response gradient with the strongest PRS association for schizophrenia (RR=1.94, (95% C.1.1.86, 2.01)), then schizoaffective BD (RR=1.37, (95% C.I. 1.22, 1.54)), BD I (RR= 1.30, (95% C.I. 1.24, 1.36)) and BD II (RR=1.04, (95% C.1. 0.97, 1.11)). Within BD cases, there was an effect gradient, indexed by the nature of psychosis, with prominent mood-incongruent psychotic features having the strongest association (RR=1.46, (95% C.1.1.36, 1.57)), followed by mood-congruent psychosis (RR= 1.24, (95% C.1. 1.17, 1.33)) and lastly, BD cases with no history of psychosis (RR= 1.09, (95% C.1. 1.04, 1.15)).

Conclusion

We show for the first time a polygenic-risk gradient, across schizophrenia and bipolar disorder, indexed by the occurrence and level of mood-incongruent psychotic symptoms.
Robust and Bright Genetically Encoded Fluorescent Markers for Highlighting Structures and Compartments in Mammalian Cells
Authors: Chertkova Anna O. , Mastop Marieke , Postma Marten , van Bommel Nikki , van der Niet Sanne , Batenburg Kevin L. , Joosen Linda , Gadella Theodorus W.J. , Okada Yasushi , Goedhart Joachim
Published: July 2017

To increase our understanding of the inner working of cells, there is a need for specific markers to identify biomolecules, cellular structures and compartments. One type of markers comprises genetically encoded fluorescent probes that are linked with protein domains, peptides and/or signal sequences. These markers are encoded on a plasmid and they allow straightforward, convenient labeling of cultured mammalian cells by introducing the plasmid into the cells. Ideally, the fluorescent marker combines favorable spectroscopic properties (brightness, photostability) with specific labeling of the structure or compartment of interest. Here, we report our ongoing efforts to generate robust and bright genetically encoded fluorescent markers for highlighting structures and compartments in living cells. The plasmids are distributed by addgene:https://www.addgene.org/browse/article/28189953/

Abstract Figure
More features, more tools, moreCrysTBox
Authors: Klinger Miloslav
Published: July 2017

A new release of theCrysTBoxsoftware is introduced. The original toolbox allows for an automated analysis of transmission electron microscope (TEM) images and for crystallographic visualization. The existing tools, which are capable of highly precise analyses of high-resolution TEM images, as well as spot, disc and ring diffraction patterns, are extended to include a tool for automatically measuring TEM sample thickness using convergent beam electron diffraction in a two-beam approximation. An implementation of geometric phase analysis is newly available, employing one of the existing tools to identify parameters and indices of crystallographic planes depicted in the input image and allowing easier and more accurate analysis. The crystallographic visualization capabilities are extended as well. Along with the simulated diffraction pattern and atomic structure, a stereographic projection and inverse pole figure tool is newly offered. A new tool able to visualize the atomic structure of two different phases and their interface is also introduced.
(1R,2R,7S,8R,9R)-N-(2-Hydroxy-2,6,6,9-tetramethyl-12-oxatricyclo[7.2.1.01,7]dodecan-8-yl)acetamide
Authors: Benharref Amed , Ait Elhad Mustapha , Mazoir Noureddine , Daran Jean-Claude , Oukhrib Abdelouahd , Berraho Moha
Published: July 2017

The title compound, C17H29NO3, was synthesized in two steps from β-himachalene (2,6,6,9-tetramethylbicyclo[5.4.01,7]undeca-1,8-diene), which was isolated from an oil of the Atlas cedar (Cedrus Atlantica). The asymmetric unit contains two independent molecules (A and B): B features an intramolecular O—H...O hydrogen bond whereas A forms an intermolecular O—H...O link to B. Each molecule is built up from a seven-membered ring to which a bridged six-membered ring is fused: the cycloheptane rings have twist-chair conformations, while the bridged cyclohexane rings display near-perfect boat conformations. In the crystal, the molecules are linked by N—H...O and O—H...O hydrogen bonds forming helical chains propagating along the b-axis direction. Some weak C—H...O interactions are also observed.
Learning control of flexible manipulator with unknown dynamics
Authors: Chen Zhiguang , Yang Chenguang , Liu Xin , Wang Min
Published: July 2017

Purpose

The purpose of this paper is to study the controller design of flexible manipulator. Flexible manipulator system is a nonlinear, strong coupling, time-varying system, which is introduced elastodynamics in the study and complicated to control. However, due to the flexible manipulator, system has a significant advantage in response speed, control accuracy and load weight ratio to attract a lot of researchers.

Design/methodology/approach

Since the order of flexible manipulator system is high, designing controller process will be complex, and have a large amount of calculation, but this paper will use the dynamic surface control method to solve this problem.

Findings

Dynamic surface control method as a controller design method which can effectively solve the problem with the system contains nonlinear and reduced design complexity.

Originality/value

The authors assume that the dynamic parameters of flexible manipulator system are unknown, and use Radial Basis Function neural network to approach the unknown system, combined with the dynamic surface control method to design the controller.
Impedance control of a cable-driven SEA with mixed H2/H∞ synthesis
Authors: Yu Ningbo , Zou Wulin
Published: July 2017

Purpose

This paper aims to present an impedance control method with mixed H2/H∞ synthesis and relaxed passivity for a cable-driven series elastic actuator to be applied for physical human–robot interaction.

Design/methodology/approach

To shape the system’s impedance to match a desired dynamic model, the impedance control problem was reformulated into an impedance matching structure. The desired competing performance requirements as well as constraints from the physical system can be characterized with weighting functions for respective signals. Considering the frequency properties of human movements, the passivity constraint for stable human–robot interaction, which is required on the entire frequency spectrum and may bring conservative solutions, has been relaxed in such a way that it only restrains the low frequency band. Thus, impedance control became a mixed H2/H∞ synthesis problem, and a dynamic output feedback controller can be obtained.

Findings

The proposed impedance control strategy has been tested for various desired impedance with both simulation and experiments on the cable-driven series elastic actuator platform. The actual interaction torque tracked well the desired torque within the desired norm bounds, and the control input was regulated below the motor velocity limit. The closed loop system can guarantee relaxed passivity at low frequency. Both simulation and experimental results have validated the feasibility and efficacy of the proposed method.

Originality/value

This impedance control strategy with mixed H2/H∞ synthesis and relaxed passivity provides a novel, effective and less conservative method for physical human–robot interaction control.
Deep Spatial-Temporal Model for rehabilitation gait: optimal trajectory generation for knee joint of lower-limb exoskeleton
Authors: Liu Du-Xin , Wu Xinyu , Du Wenbin , Wang Can , Chen Chunjie , Xu Tiantian
Published: July 2017

Purpose

The purpose of this paper is to model and predict suitable gait trajectories of lower-limb exoskeleton for wearer during rehabilitation walking. Lower-limb exoskeleton is widely used for assisting walk in rehabilitation field. One key problem for exoskeleton control is to model and predict suitable gait trajectories for wearer.

Design/methodology/approach

In this paper, the authors propose a Deep Spatial-Temporal Model (DSTM) for generating knee joint trajectory of lower-limb exoskeleton, which first leverages Long-Short Term Memory framework to learn the inherent spatial-temporal correlations of gait features.

Findings

With DSTM, the pathological knee joint trajectories can be predicted based on subject’s other joints. The energy expenditure is adopted for verifying the effectiveness of new recovery gait pattern by monitoring dynamic heart rate. The experimental results demonstrate that the subjects have less energy expenditure in new recovery gait pattern than in others’ normal gait patterns, which also means the new recovery gait is more suitable for subject.

Originality/value

Long-Short Term Memory framework is first used for modeling rehabilitation gait, and the deep spatial–temporal relationships between joints of gait data can obtained successfully.
Compliant training control of ankle joint by exoskeleton with human EMG-torque interface
Authors: Li Zhan , Cheng Hong , Guo Hongliang , Sun Xiaohong
Published: July 2017

Purpose

The purpose of this paper is to make compliant training control of exoskeleton for ankle joint with electromyograph (EMG)-torque interface.

Design/methodology/approach

A virtual compliant mapping which is modeled by mass-spring-damper system is incorporated into the whole system at the reference input. The EMG-torque interface contains both data acquisition and torque estimator/predictor, and extreme learning machine is utilized for joint torque estimation/prediction from multiple channels of EMG signals.

Findings

The reference ankle joint angle to follow is produced from the compliance mapping whose input is the measured/predicted torque on healthy subjects. The control system works well with the desired angle to track. In the actuation level, the input torque to drive the ankle exoskeleton is less than the actual torque of the subject(s). This may have positive influence on diminishing overshoot of input torque from motors and protect the actuators. The torque prediction and final tracking control performance demonstrate the efficiency of the presented architecture.

Originality/value

This work can be beneficial to compliant training of ankle exoskeleton system for pilots and enhance current training control module in rehabilitation.
Genetic algorithm-based compliant robot path planning: an improved Bi-RRT-based initialization method
Authors: Lin Du , Shen Bo , Liu Yurong , Alsaadi Fuad E. , Alsaedi Ahmed
Published: July 2017

Purpose

The purpose of this paper is to improve the performance of the genetic algorithm-based compliant robot path planning (GACRPP) in complex dynamic environment by proposing an improved bidirectional rapidly exploring random tree (Bi-RRT)-based population initialization method.

Design/methodology/approach

To achieve GACRPP in complex dynamic environment with high performance, an improved Bi-RRT-based population initialization method is proposed. First, the grid model is adopted to preprocess the working space of mobile robot. Second, an improved Bi-RRT is proposed to create multi-cluster connections between the starting point and the goal point. Third, the backtracking method is used to generate the initial population based on the multi-cluster connections generated by the improved Bi-RRT. Subsequently, some comparative experiments are implemented where the performances of the improved Bi-RRT-based population initialization method are compared with other population initialization methods, and the comparison results of the improved genetic algorithm (IGA) combining with the different population initialization methods are shown. Finally, the optimal path is further smoothed with the help of the technique of quadratic B-spline curves.

Findings

It is shown in the experiment results that the improved Bi-RRT-based population initialization method is capable of deriving a more diversified initial population with less execution time and the IGA combining with the proposed population initialization method outperforms the one with other population initialization methods in terms of the length of optimal path and the execution time.

Originality/value

In this paper, the Bi-RRT is introduced as a population initialization method into the GACRPP problem. An improved Bi-RRT is proposed for the purpose of increasing the diversity of initial population. To characterize the diversity of initial population, a new notion of breadth is defined in terms of Hausdorff distance between different paths.
Public-sector reforms and balanced scorecard adoption: an Ethiopian case study
Authors: Bobe Belete Jember , Mihret Dessalegn Getie , Obo Degefe Duressa
Published: July 2017

Purpose

The purpose of this paper is to examine adoption of the balanced scorecard (BSC) by a large public-sector health organisation in an African country, Ethiopia as part of a programme to implement a unified sector-wide strategic planning and performance monitoring system. The study explains how this trans-organisational role of the BSC is constituted, and explores how it operates in practice at the sector-and organisation-levels.

Design/methodology/approach

The study employs the case-study method. Semi-structured interview data and documentary evidence are analysed by drawing on the concept of translation from actor-network theory.

Findings

The case-study organisation adopted the BSC as a part of broader public-sector reforms driven by political ideology. Through a centralised government decision, the BSC was framed as a sector-wide system aimed at: aligning the health sector’s strategic policy goals with strategic priorities and operational objectives of organisations in the sector; and unifying performance-monitoring of the sector’s organisations by enabling aggregation of performance information to a sector level in a timely manner to facilitate health sector policy implementation. While the political ideology facilitated BSC adoption for trans-organisational use, it provided little organisational discretion to integrate financial administration and human resource management practices to the BSC framework. Further, inadequate piloting of information system use for the anticipated BSC model, originating from the top-down approach followed in the BSC implementation, inhibited implementation of the BSC with a balanced emphasis between the planning and performance monitoring roles of the BSC. As a result, the BSC underwent a pragmatic shift in emphasis and was reconceptualised as a system of enhancing strategic alignment through integrated planning, compared to the balanced emphasis between the planning and performance monitoring roles initially anticipated.

Originality/value

The study provides a theory-based explanation of how politico-ideological contexts might facilitate the framing of novel roles for the BSC and how the roles translate into practice.
The accounting profession and education
Authors: Verhoef Grietjie , Samkin Grant
Published: July 2017

Purpose

The purpose of this paper is to examine how the actions of the accounting profession, the state, universities, and academics have inhibited the development of South African accounting research.

Design/methodology/approach

A multiple history approach using traditional archival material and oral history is used.

Findings

Since the late nineteenth-century, a network of human and non-human actors has ensured that accounting education in South Africa retained a technical focus. By prescribing and detailing the accounting syllabuses required for university accreditation, the South African Institute of Chartered Accountants (SAICA) and its predecessors exercise direct control over accounting education. As a result, little appetite exists for a discipline based on academic enquiry or engagement with international scholars. While the SAICA claims to support accounting research, this support is conditional on its meeting the professional body’s particular view of scholarship.

Research limitations/implications

The limitations associated with this research are that it focusses on one particular professional body in one jurisdiction. The South African situation provides a cautionary tale of how universities, particularly those in developing countries, should take care not to abdicate their responsibilities for the setting of syllabi or course content to professional bodies. Accounting academics, particularly those in a developing country currently experiencing major social, political, and economic problems, are in a prime position to engage in research that will benefit society as a whole.

Originality/value

Although actor network theory has been used in accounting research and in particular to explain accounting knowledge creation, the use of this particular theoretical lens to examine the construction of professional knowledge is limited. This study draws on Callon’s (1986) four moments to explain how various human actors including the accounting profession, the state, universities, and accounting academics, along with non-human actors such as accreditation, regulation, and transformation, have brought about South African academic disengagement with the discipline.
The anatomy of business failure
Authors: Dias Artur , Teixeira Aurora A.C.
Published: July 2017

Purpose

The purpose of this paper is to analyze the aftermath of business failure (BF) by addressing: how the individual progressed and developed new ventures, how individuals changed business behaviors and practices in light of a failure, and what was the effect of previous failure on the individual’s decisions to embark on subsequent ventures.

Design/methodology/approach

The authors resort to qualitative methods to understand the aftermath of BF from a retrospective point of a successful entrepreneur. Specifically, the authors undertook semi-structured interviews to six entrepreneurs, three from the north of Europe and three from the south and use interpretative phenomenological analysis.

Findings

The authors found that previous failure impacted individuals strongly, being shaped by the individual’s experience and age, and their perception of blame for the failure. An array of moderator costs was identified, ranging from antecedents to institutions that were present in the individual’s lives. The outcomes are directly relatable to the failed experience by the individual. The authors also found that the failure had a significant effect on the individual’s career path.

Originality/value

While predicting the failure of healthy firms or the discovery of the main determinants that lead to such an event have received increasingly more attention in the last two decades, the focus on the consequences of BF is still lagging behind. The present study fills this gap by analyzing the aftermath of BF.
Response of fire exposed composite girders under dominant flexural and shear loading
Authors: Naser Mohannad , Kodur Venkatesh
Published: July 2017

Purpose

This paper aims to present results from numerical studies on the response of fire exposed composite girders subjected to dominant flexural and shear loading. A finite element-based numerical model was developed to trace the thermal and structural response of composite girders subjected to simultaneous structural loading and fire exposure. This model accounts for various critical parameters including material and geometrical nonlinearities, property degradation at elevated temperatures, shear effects, composite interaction between concrete slab and steel girder, as well as temperature-induced local buckling. To generate test data for validation of the model, three composite girders, each comprising of hot-rolled (standard) steel girder underneath a concrete slab, were tested under simultaneous fire and gravity loading.

Design/methodology/approach

The validated model was then applied to investigate the effect of initial geometric imperfections, load level, thickness of slab and stiffness of shear stud on fire response of composite girders.

Findings

Results from experimental and numerical analysis indicate that the composite girder subjected to flexural loading experience failure through flexural yielding mode, while the girders under shear loading fail through in shear web buckling mode. Further, results from parametric studies clearly infer that shear limit state can govern the response of fire exposed composite girders under certain loading configuration and fire scenario.

Originality/value

This paper presents results from numerical studies on the response of fire exposed composite girders subjected to dominant flexural and shear loading.
Fire resistance of extruded hollow-core slabs
Authors: Hertz Kristian , Giuliani Luisa , Sørensen Lars Schiøtt
Published: July 2017

Purpose

Prefabricated extruded hollow-core slabs are preferred building components for floor structures in several countries. It is therefore important to be able to document the fire resistance of these slabs proving fulfilment of standard fire resistance requirements of 60 and 120 min found in most national building regulations. The paper aims to present a detailed analysis of the mechanisms responsible for the loss of load-bearing capacity of hollow-core slabs when exposed to fire.

Design/methodology/approach

Furthermore, it compares theoretical calculation and assessment according to the structural codes with data derived from a standard fire test and from a thorough examination of the comprehensive test documentation available on fire exposed hollow-core slabs.

Findings

Mechanisms for loss of load-bearing capacity are clarified, and evidence of the fire resistance is found.

Originality value

For the first time, the mechanisms responsible for loss of load-bearing capacity are identified, and test results and calculation approach are for the first time applied in accordance with each other for assessment of fire resistance of the structure.
Thermal behaviour of unstressed and stressed high strength concrete containing polypropylene fibers at elevated temperature
Authors: Cree Duncan , Pliya Prosper , Green Mark F. , Noumowé Albert
Published: July 2017

Purpose

The purpose of this paper is to evaluate high strength concrete (HSC) containing polypropylene fibers (PP-fibers) at high temperature under a compressive load.

Design/methodology/approach

The use of PP fibers in HSC is known to reduce and at times eliminate the risk of spalling. HSC containing 0, 1 and 2 kg/m3 of PP-fibers were subjected to various temperatures from 20°C to 150°C, 300°C and 450°C and evaluated in a “hot condition”. One group of specimens was in a non-stressed condition during heating (unstressed hot), while a second group was subjected to an initial preload of 40 per cent of the room temperature compressive strength during the heating (stressed hot).

Findings

Results showed that stressed concrete containing PP-fibers had lower thermal gradients (the temperature difference between the surface and center temperatures as a function of radial distance) and a decrease in relative porosity. However, the compressive strength of stressed specimens was improved with or without fibers as compared to that of the unstressed HSC. The increased stress levels due to concrete expansion at elevated temperature were also reported. The PP-fibers did not have a significant effect on the compressive strength of stressed concrete as compared to the unstressed state.

Originality/value

This paper reports the compressive strength of PP-fibers in HSC at elevated temperature with and without a pre-load.
Mechanical properties of low-strength concrete at exposure to elevated temperatures
Authors: Rafi Muhammad Masood , Aziz Tariq , Lodi Sarosh Hashmat
Published: July 2017

Purpose

This paper aims to present the results of testing of low-strength concrete specimens exposed to elevated temperatures. These data are limited in the existing literature and do not exist in Pakistan.

Design/methodology/approach

An experimental testing programme has been employed. Cylindrical specimens of 100 × 200 mm were used in the testing programme. These were heated at temperatures which were varied from 100°C to 900°C in increment of 100°C. Similar specimens were tested at ambient temperature as control specimens. The compressive and tensile properties of heat treated specimens were determined.

Findings

The colour of concrete started to change at 300°C and hairline cracks appeared at 400°C. Explosive spalling was observed in few specimens in the temperature range of 400°C-650°C which could be attributed to the pore pressure generated by steam. Significant loss of concrete compressive strength occurred on heating temperatures larger than 600°C, and the residual compressive strength was found to be 15 per cent at 900°C. Residual tensile strength of concrete became less than 10 per cent at 900°C. The loss of concrete stiffness reached 85 per cent at 600°C. Residual Poisson’s ratio of concrete increased at high temperatures and became nearly six times larger at 900°C as compared to that at ambient temperature.

Research limitations/implications

The parameters of the study included heating temperature and effects of temperature on strength and stiffness properties of the concrete specimens.

Practical implications

Building fire incidents have increased in Pakistan. As a large number of reinforced concrete (RC) buildings exist in the country, the data related to elevated temperature properties of concrete are required. These data are not available in Pakistan presently. The study aims at providing this information for the design engineers to enable them to assess and increase fire resistance of RC structural members.

Originality/value

The presented study is unique in its nature in that there is no published contribution to date, to the best of authors’ knowledge, which has been carried out to assess the temperature-dependent mechanical properties of concrete in Pakistan.
Exploring the antecedents of ambidexterity: a taxonomic approach
Authors: Asif Muhammad
Published: July 2017

Purpose

Ambidexterity is the ability of an organization to balance exploitation and exploration. Ambidextrous organizations perform better in managing productivity-innovation dilemma. Although the literature on ambidexterity has expanded, much less attention has been paid to the antecedents of ambidexterity. The purpose of this paper is to explore the antecedents of ambidexterity and develop a multi-level taxonomy of the antecedents.

Design/methodology/approach

Based on an extensive review of the literature, the paper develops criteria for categorizing the antecedents and then develops a taxonomy of the antecedents.

Findings

Two taxonomy frameworks have been developed: one is based on infrastructural elements, including organizational structures, processes, and context, while the other is based on different organizational levels (i.e. organizational, group, and individual) at which different antecedents exist. Most of the antecedents of ambidexterity reported in the literature fall in the category of “processes” – both individual/social and technical/procedural.

Practical implications

The paper provides an enhanced understanding of the antecedents of ambidexterity, how they relate to each other, and how they can be grouped together. The framework can help managers to apply the antecedents at various organizational levels, resulting in a more structured approach to ambidexterity.

Originality/value

The key contribution of the paper is in providing a multi-level understanding of the antecedents of ambidexterity. To the best of the author’s knowledge, such a taxonomy of the antecedents of ambidexterity has not been provided in previous publications.
Mutual funds in Greece: case study of domestic equity mutual funds during a financial crisis
Authors: Koutsokostas Drosos , Papathanasiou Spyros
Published: July 2017

Purpose

The purpose of this paper is to examine the performance of Greek equity mutual funds for the period 2012-2016, analyzing further the selectivity and market timing ability, and short-term performance persistence for the period 2015-2016.

Design/methodology/approach

Utilizing a survivorship-bias-controlled sample of 25 funds and daily data, the authors use single-index (Jensen, 1968) and multi-factor (Carhart, 1997) models to evaluate risk-adjusted returns using the General Index of Athens Stock Exchange as a benchmark. The Treynor-Mazuy (1966) and Henriksson-Merton (1981) models are used to assess the stock selection and market timing abilities of fund managers. In order to investigate short-term performance persistence, the authors implement a variety of parametric (Bollen and Busse, 2005) and nonparametric tests (Malkiel, 1995; Brown and Goetzmann, 1995; Kahn and Rudd, 1995).

Findings

Results show that the funds underperformed the General Index, mainly due to the managers’ market timing inability. Furthermore, weak evidence for short-term performance persistence has been documented.

Research limitations/implications

Checking for performance persistence, it was impossible to rank funds and form deciles according to their estimated abnormal returns, as in Bollen and Busse (2005), due to the small number of mutual funds operating in Greece.

Originality/value

Empirical studies regarding the performance of Greek equity mutual funds are still limited. Therefore, this paper intends to fill this gap by providing further evidence of performance evaluation.
Rethinking educational tourism: proposing a new model and future directions
Authors: McGladdery Christine A. , Lubbe Berendien A.
Published: July 2017

Purpose

Educational tourism is under-researched in the literature. The purpose of this paper is to argue that this stems from a lack of consensus regarding the nature and scope of educational tourism as a theoretical concept and market segment.

Design/methodology/approach

Through a review of research over the last decade and a half, the paper aims at providing a concise overview of the key perspectives and concepts in educational tourism whilst highlighting the potential for future directions of the sector.

Findings

Ritchie’s (2003) segmentation model of educational tourism is usually considered the international standard for writing on the subject. However, it excludes certain sectors of tourism that may be considered educational. In response to this, a new conceptual model is presented. Further research is needed to understand the schools’ educational tourism market. When international educational tourism is considered, the majority of empirical research and academic debate has originated in the closely related field of international education. Educational tourism has the potential for hybridisation with other segments of tourism and non-tourism sectors and to contribute towards global peace.

Originality/value

This paper offers an alternative process-driven and outcomes-based conceptual model of educational tourism. It identifies directions for future research in schools’ and international educational tourism and proposes a typology to aid hybridisation of the phenomenon with other sectors. Finally, it discusses the potential of educational tourism to foster peace through the integration of global learning into touristic practice.
Preparedness: Unpacking and clarifying the concept
Authors: Staupe‐Delgado Reidar , Kruke Bjørn Ivar
Published: July 2017

Crisis studies increasingly focus on developing proactive strategies to minimize the effects of unwanted occurrences and contingencies. Preparedness constitutes a key component of this approach, as many crises are difficult to prevent. However, at the conceptual and practical levels, it remains difficult to distinguish preparedness from other crisis‐related concepts. This study draws on an extensive survey of the preparedness literature with the goal of elucidating its defining attributes. The results show that preparedness can be minimally characterized as measures that are of an active, continuous and anticipatory nature. Contextually definitions, however, may also include social, planned, non‐structural or enabling conceptual attributes.
Evolutionary changes of Hox genes and relevant regulatory factors provide novel insights into mammalian morphological modifications
Authors: LI Kui , SUN Xiaohui , CHEN Meixiu , SUN Yingying , TIAN Ran , WANG Zhengfei , XU Shixia , YANG Guang
Published: July 2017

The diversity of body plans of mammals accelerates the innovation of lifestyles and the extensive adaptation to different habitats, including terrestrial, aerial and aquatic habitats. However, the genetic basis of those phenotypic modifications, which have occurred during mammalian evolution, remains poorly explored. In the present study, we synthetically surveyed the evolutionary pattern of Hox clusters that played a powerful role in the morphogenesis along the head–tail axis of animal embryos and the main regulatory factors (Mll, Bmi1 and E2f6) that control the expression of Hox genes. A deflected density of repetitive elements and lineage‐specific radical mutations of Mll have been determined in marine mammals with morphological changes, suggesting that evolutionary changes may alter Hox gene expression in these lineages, leading to the morphological modification of these lineages. Although no positive selection was detected at certain ancestor nodes of lineages, the increased ω values of Hox genes implied the relaxation of functional constraints of these genes during the mammalian evolutionary process. More importantly, 49 positively‐selected sites were identified in mammalian lineages with phenotypic modifications, indicating adaptive evolution acting on Hox genes and regulatory factors. In addition, 3 parallel amino acid substitutions in some Hox genes were examined in marine mammals, which might be responsible for their streamlined body.
Inter‐group associations in Mongolian gerbils: Quantitative evidence from social network analysis
Authors: DENG Ke , LIU Wei , WANG Dehua
Published: July 2017

Animals often interact non‐randomly with conspecifics, and association preferences can differ across life‐history stages to maximize individuals' fitness. Mongolian gerbils (Meriones unguiculatus) are a social rodent that live in highly seasonal habitats and display seasonal fluctuations in population density, growth rate and the size of overlapped home ranges. Nevertheless, whether gerbils modify their social relationships at different life‐history stages remains unknown. Here, we used social network analysis to examine whether social associations differ between the sexes and between life‐history stages in a wild population of Mongolian gerbils. We quantified social attributes at both group level (assortativity) and individual level (social differentiation and degree, closeness and betweenness centrality); these attributes reflect individuals' social preferences and their potential influence on others in the network. We found that both male and female gerbils established fewer inter‐group social connections during the food‐hoarding season than during the breeding season, revealing constraints on sociality. Similarly, during the food‐hoarding season, degree centrality and social differentiation increased significantly whereas closeness and betweenness centrality decreased significantly. Together, these results suggest that gerbils have relatively more partners and preferred associations and decreased influence over others in the network during the food‐hoarding season. In addition, we found no significant difference in any of the social attribute between males and females, but there was a significant interaction effect between sex and season on degree, closeness and betweenness centrality. Our results demonstrate that Mongolian gerbils adjust their association strategies to adapt to the changes of life history. Such adjustments may balance the costs/benefits associated with survival and reproduction.
Emergency appendicectomy in Australia: findings from a multicentre, prospective study
Authors: Arthur Thomas , Gartrell Richard , Manoharan Bavahuna , Parker David ,   QUEST Collaboration
Published: July 2017

Background

Emergency appendicectomy is the most common emergency surgical procedure performed in Australia. Despite this frequency, there is a relative paucity of contemporary, broad‐based, local data that examine how emergency appendicectomies are currently performed and what are the outcomes from these operations.

Methods

A multicentre, prospective, observational study was performed. Patients were recruited by local investigators for a period of 2 months with 30‐day follow‐up. Patients were eligible for study inclusion if they underwent an emergency appendicectomy for suspected acute appendicitis. The primary outcome of the study was the negative appendicectomy rate (NAR), with secondary outcomes including 30‐day complication rates, method of operation and conversion rates.

Results

A total of 1189 patients were recruited across 27 centres. The NAR across all centres was 19.0%. 98.2% of appendicectomies were performed with a laparoscopic‐first approach. The rate of conversion from laparoscopy to open operation was 2.4%. 9.4% of patients were recorded as having one or more of the following complications: readmission (6.6%), surgical site infection (1.9%), intra‐abdominal abscess (2.7%) or further intervention (1.5%). Patients who had an open operation had higher rates of readmission and surgical site infection.

Conclusion

The NAR found in this study is within the traditional measures of acceptance; however, this rate is high when measured against modern international benchmarks.
Prognostic value of positron emission tomography/computed tomography for adjuvant chemotherapy of colon cancer
Authors: Baik HyungJoo , Lee Seok Mo , Seo Sang Hyuk , An Min Sung , Kim Kwang Hee , Bae Ki Beom , Oh Min Kyung , Hong Kwan Hee
Published: July 2017

Background

To assess the prognostic value of preoperative 18F‐fluorodeoxyglucose positron emission tomography/computed tomography in patients with high‐risk stage II or stage III colon cancer who underwent FOLFOX chemotherapy.

Methods

The study included 166 patients with high‐risk stage II or stage III colon cancer who received FOLFOX4 chemotherapy. Retrospective patient data were analysed including pathological stage, histology, disease‐free survival (DFS) and the maximum standardized uptake value (SUVmax) of the primary tumour on 18F‐fluorodeoxyglucose positron emission tomography/computed tomography. The primary end point was DFS.

Results

There were recurrences in 29 of the 166 patients (17.4%). Measuring the area under the receiver operating characteristic curve, the cut‐off value of SUVmax with maximum sensitivity and specificity was 10.95. Using the Kaplan–Meier method, the DFS of the patients categorized by SUVmax tended to differ (P = 0.055). In univariate analyses, the risk factors for DFS were age over 70 years, higher N stage and neural invasion. SUVmax ≤ 10.95 showed a tendency, but was not significant (P = 0.0604). In multivariate analyses, the risk factors for DFS were age over 70 and neural invasion.

Conclusions

The results of this study suggest that high fluorodeoxyglucose uptake of the primary mass in high‐risk stage II and stage III colon cancer does not significantly correlate with DFS.
Promoting Positive Youth Development Through School‐Based Social and Emotional Learning Interventions: A Meta‐Analysis of Follow‐Up Effects
Authors: Taylor Rebecca D. , Oberle Eva , Durlak Joseph A. , Weissberg Roger P.
Published: July 2017

This meta‐analysis reviewed 82 school‐based, universal social and emotional learning (SEL) interventions involving 97,406 kindergarten to high school students (Mage = 11.09 years; mean percent low socioeconomic status = 41.1; mean percent students of color = 45.9). Thirty‐eight interventions took place outside the United States. Follow‐up outcomes (collected 6 months to 18 years postintervention) demonstrate SEL's enhancement of positive youth development. Participants fared significantly better than controls in social‐emotional skills, attitudes, and indicators of well‐being. Benefits were similar regardless of students’ race, socioeconomic background, or school location. Postintervention social‐emotional skill development was the strongest predictor of well‐being at follow‐up. Infrequently assessed but notable outcomes (e.g., graduation and safe sexual behaviors) illustrate SEL's improvement of critical aspects of students’ developmental trajectories.
Prediction of outcome after curative surgery for colorectal cancer: preoperative haemoglobin, C‐reactive protein and albumin
Authors: Egenvall M. , Mörner M. , Martling A. , Gunnarsson U.
Published: July 2017

Aim

The aim was to evaluate a scoring system using the values of preoperative haemoglobin, C‐reactive protein (CRP) and albumin to predict colorectal cancer recurrence and survival.

Method

Data on all curative resections for Stages I–III colorectal cancer performed at a tertiary referral hospital in 2007–2010 were recorded in the Swedish Colorectal Cancer Registry and were matched to local databases for laboratory results and blood transfusion. Patients who died within 30 days or during primary hospital admission were excluded. Preoperative haemoglobin, CRP and albumin levels were recorded for 417 patients. A score (0–3) was derived on the presence of anaemia (Hb < 120 g/l for women and < 130 g/l for men), raised CRP (> 10 mg/ml) and low albumin (< 35 g/dl). The risks for recurrence and impaired overall survival were assessed using Cox regression analyses.

Results

Impaired overall survival was found when one, two or three of the criteria anaemia, elevated CRP and low albumin were present prior to surgery [hazard ratio (HR) 3.61, 95% CI 1.66–7.85; HR 3.91, 95% CI 1.75–8.74; HR 4.85, 95% CI 2.15–10.93, respectively]. The risk for recurrence, however, was not related to the presence of these criteria.

Conclusion

Overall survival after curative surgery for Stages I–III colorectal cancer is impaired when anaemia, elevated CRP or low albumin exist prior to surgery.
EUS‐FNA of the Merkel cell carcinoma metastasis to the pancreas: Cytomorphology and immunocytochemistry on direct cytological smears
Authors: Stoos‐Veic T. , Tadic M. , Aralica G. , Milicic V. , Tomasovic‐Loncaric C.
Published: July 2017

Objective

To report two cases of Merkel cell carcinoma (MCC) metastatic to the pancreas diagnosed with endoscopic ultrasound‐guided‐fine needle aspiration (EUS‐FNA) and to add the case of concomitant chronic lymphocytic leukaemia/small lymphocytic lymphoma (CLL/SLL) and MCC to the literature. The aim is to alert the cytopathologists once more to the problems of differential diagnosis of pancreatic metastasis of MCC and to describe the possibilities of ancillary methods performed on direct cytological smears.

Methods

EUS‐FNA procedures were performed according to standard institution protocol, using 22‐G needles with cytopathologist on‐site. Based on rapid on‐site evaluation (ROSE), additional passes were made for immunocytochemistry (ICC). A mini panel of antibodies was used to aid the differential diagnosis.

Results

Smears revealed a dispersed pattern of small round cells with scant cytoplasm, round nuclei with inconspicuous nucleoli and occasional nuclear moulding, suspicious of small cell carcinoma. Results of ICC applied to the direct cytological smears were as follows: LCA negative, Cytokeratin (clone MNF116) positive, TTF‐1 negative, CD 56 positive, NSE weakly positive, Chromogranin A weakly positive and CK20 positive, in one case in a dot‐like perinuclear pattern. The diagnosis of MCC was made.

Conclusion

Increasing incidence of MCC warrants the inclusion of MCC in the differential diagnosis of tumours of small round blue cell morphology even in unusual sites. The cytomorphological features coupled with an ICC panel are usually enough to make a confident diagnosis of MCC. EUS‐FNA is a minimally invasive technique which enables sampling adequate tissue for all the ancillary methods eventually needed to support the diagnosis.