bluuebunny/crossref_metadata_2025 huggingface dataset:
FGA-MMF method for the simulation of two-phase flows
Authors: Behrangi Farhang , Banihashemi Mohammad Ali , Montazeri Namin Masoud , Bohluly Asghar
Published: April 2018

Purpose

This paper aims to present a novel numerical technique for solving the incompressible multiphase mixture model.

Design/methodology/approach

The multiphase mixture model contains a set of momentum and continuity equations for the mixture phase, a second phase continuity equation and the algebraic equation for the relative velocity. For solving continuity equation for the second phase and advection term of momentum, an improved approach fine grid advection-multiphase mixture flow (FGA-MMF) is developed. In the FGA-MMF method, the continuity equation for the second phase is solved with higher-order schemes in a two times finer grid. To solve the advection term of the momentum equation, the advection fluxes of the volume fraction in the continuity equation for the second phase are used.

Findings

This approach has been used in various tests to simulate unsteady flow problems. Comparison between numerical results and experimental data demonstrates a satisfactory performance. Numerical examples show that this approach increases the accuracy and stability of the solution and decreases non-monotonic results.

Research limitations/implications

The solver for the multi-phase mixture model can only be adopted to solve the incompressible fluid flow.

Originality/value

The paper developed an innovative solution (FGA-MMF) to find multi-phase flow field value in the multi-phase mixture model. Advantages of the FGA-MMF technique are the ability to accurately determine the phases interpenetrating, decreasing the numerical diffusion of the interface and preventing instability and non-monotonicity in solution of large density variation problems.
Adaptive finite element analysis for damage detection of non-uniform Euler–Bernoulli beams with multiple cracks based on natural frequencies
Authors: Wang Yongliang , Ju Yang , Zhuang Zhuo , Li Chenfeng
Published: April 2018

Purpose

This study aims to develop an adaptive finite element method for structural eigenproblems of cracked Euler–Bernoulli beams via the superconvergent patch recovery displacement technique. This research comprises the numerical algorithm and experimental results for free vibration problems (forward eigenproblems) and damage detection problems (inverse eigenproblems).

Design/methodology/approach

The weakened properties analogy is used to describe cracks in this model. The adaptive strategy proposed in this paper provides accurate, efficient and reliable eigensolutions of frequency and mode (i.e. eigenpairs as eigenvalue and eigenfunction) for Euler–Bernoulli beams with multiple cracks. Based on the frequency measurement method for damage detection, using the difference between the actual and computed frequencies of cracked beams, the inverse eigenproblems are solved iteratively for identifying the residuals of locations and sizes of the cracks by the Newton–Raphson iteration technique. In the crack detection, the estimated residuals are added to obtain reliable results, which is an iteration process that will be expedited by more accurate frequency solutions based on the proposed method for free vibration problems.

Findings

Numerical results are presented for free vibration problems and damage detection problems of representative non-uniform and geometrically stepped Euler–Bernoulli beams with multiple cracks to demonstrate the effectiveness, efficiency, accuracy and reliability of the proposed method.

Originality/value

The proposed combination of methodologies described in the paper leads to a very powerful approach for free vibration and damage detection of beams with cracks, introducing the mesh refinement, that can be extended to deal with the damage detection of frame structures.
Automated layout design of multi-span reinforced concrete beams using charged system search algorithm
Authors: Uz Mehmet Eren , Sharafi Pezhman , Askarian Mahya , Fu Weiqing , Zhang Chunmei
Published: April 2018

Purpose

The preliminary layout design of structures impacts upon the entire design process and, consequently, the total cost. The purpose of this paper is to select the most economical layouts that satisfy structural and architectural requirements, while considering the reciprocal effects of cost factors and layout variables at the preliminary stages of design.

Design/methodology/approach

This paper presents an automated method for cost optimization of geometric layout design of multi-span reinforced concrete (RC) beams subjected to dynamic loading by using the charged system search (CSS) algorithm. First, a novel cost optimization approach for geometric layout problems is introduced, in which both cost parameters and dynamic responses are considered in the preliminary layout design of beams. The proposed structural optimization problem with constraints on the static and dynamic equilibrium, architectural dimensions and structural action effects is solved using the CSS algorithm.

Findings

The proposed CSS algorithm for solving the cost optimization problem can be easily used for optimizing the span lengths and is also capable of working with various cost functions. The presented examples show that the proposed algorithm using the new cost optimization function provides satisfactory results and can result in over 7 per cent cost saving.

Originality/value

This is an original paper proposing a novel methodology for preliminary layout design of concrete beams.
Nonlinear temperature and thermal stress analysis of annular fins with time dependent boundary condition
Authors: Lee Sen-Yung , Chou Li-Kuo , Chen Chao Kuang
Published: April 2018

Purpose

The purpose of this paper is to propose the Laplace Adomian Decomposition Method (LADM) for studying the nonlinear temperature and thermal stress analysis of annular fins with time-dependent boundary condition.

Design/methodology/approach

The nonlinear behavior of temperature and thermal stress distribution in an annular fin with rectangular profile subjected to time-dependent periodic temperature variations at the root is studied by the LADM. The radiation effect is considered. The convective heat transfer coefficient is considered as a temperature function.

Findings

The proposed solution method is helpful in overcoming the computational bottleneck commonly encountered in industry and in academia. The results show that the circumferential stress at the root of the fin will be important in the fatigue analysis.

Originality/value

This study presents an effective solution method to analyze the nonlinear behavior of temperature and thermal stress distribution in an annular fin with rectangular profile subjected to time-dependent periodic temperature variations at the root by using LADM.
A note on the stiffness and flexibility natural approach to the triangular spring cell
Authors: Doltsinis I. St
Published: April 2018

Purpose

An intended numerical analysis of solids and structures by spring cell substitutes in place of finite elements has occasioned considerable research on the subject. This paper aims to expose two alternative concepts evolving out of Argyris’ natural approach to the simplex triangular element. One is based on an approximation of the element flexibility and the other approximates the stiffness with coincidence at the ideal conditions of complete substitution.

Design/methodology/approach

Characteristic of the natural formalism is the homogeneous definition of strain and stress along the sides of the triangular element. The associated elastic compliance offers itself for the transition to the spring cell. The diagonal entities are interpreted immediately as springs along the element sides, and the off-diagonal terms account for the completeness of the substitution. In addition to the flexibility concept, the spring cell is deduced alternatively from the element’s natural stiffness. The difference in the flexibility result lies in the calculatory cross-sectional areas of the elastic bar members.

Findings

From the natural point of view, the spring cell evolves out of the continuum element to the desired degree of substitution. The simplest configuration of pin-joined bars discards all geometrical and physical cross effects. The approach is attractive because of its transparent simplicity.

Research limitations/implications

The difference between the stiffness and the flexibility approach to spring cells is demonstrated for triangular elements that suit the problems lying in plane stress or plane strain. More general states of stress and strain involve spring cell counterparts of the tetrahedral finite element.

Practical implications

Apart from plane geometries, triangular spring cells are assembled to lattice models of space structures, such as membrane shells and similar.

Originality/value

The natural formalism of simplex finite elements is used for deducing spring cells in two variants and exploring their properties. This is a novel approach to spring cells and an original employment of the natural concept.
Development of a crisis in a project: a process perspective
Authors: Simard Magali , Laberge Danielle
Published: April 2018

Purpose

The purpose of this paper is to analyze the development and outbreak of a crisis in a high-priority project within a large organization.

Design/methodology/approach

Single-case study using extreme case sampling, a type of purposeful sampling, because this case provides rich information on a rare research opportunity: a project crisis that emerged during the fieldwork. Research data are semi-structured interviews, observations, project and organization documentation, logbook, notes and memos.

Findings

The paper shows the relevance of notions from organizational crisis management to an internal crisis in a temporary setting. This allowed a deeper understanding of crisis development. The paper reveals the wealth of meaningful, transparent data that can be collected when a crisis emerges. It highlights the high potential of project crises to reveal parent organizations’ dysfunctions. Indeed, findings suggest that the parent organization’s usual project management practices greatly contributed to the crisis affecting this project, which was unusually large and complex.

Research limitations/implications

The main potential limitation relates to transferability. However, a single-case study is appropriate when it represents a rare phenomenon that is not easily accessible for researchers – a crisis outbreak.

Practical implications

Results can provide insights enabling practitioners to improve their understanding of the ambiguous, stressful situations created by a crisis.

Originality/value

The results show the relevance of notions from organizational crisis management to the development of a project crisis and demonstrate the potentially harmful impact of a parent organization’s “usual” practices, especially on “unusually” large and complex projects.
Environmental performance measurement for green supply chains
Authors: Tuni Andrea , Rentizelas Athanasios , Duffy Alex
Published: April 2018

Purpose

The majority of the environmental impacts in a typical supply chain can arise beyond the focal firm boundaries. However, no standardised method to quantify these impacts at the supply chain level currently exists. The purpose of this paper is to identify the quantitative methods developed to measure the environmental performance of supply chains and evaluate their key features.

Design/methodology/approach

A systematic literature review is conducted at the intersection of performance measurement and green supply chain management (GSCM) fields, covering 78 publications in peer-reviewed academic journals. The literature is reviewed according to several perspectives, including the environmental aspects considered, the main purpose of measurement, model types and the extent of supply chain covered by performance measurements.

Findings

Adopted environmental metrics show a low degree of standardisation and focus on natural resources, energy and emissions to air. The visibility and traceability of environmental aspects are still limited; the assessment of environmental impacts does not span in most cases beyond the direct business partners of the focal firms. A trade-off was observed between the range of environmental aspects and the extent of the supply chain considered with no method suitable for a holistic evaluation of the environmental supply chain performance identified. Three major streams of research developing in the field are identified, based on different scope.

Originality/value

This paper is the first attempt to examine in detail what tiers of the supply chain are actually involved in green performance assessment, ultimately contributing to clarify the scope of the supply chain dimension in GSCM performance measurement research. The work also recognises which methods are applicable to extended supply chains and explores how different methodologies perform in terms of supply chain extent covered.
Competitive performance as a substitute for competiveness measurement in tourism destinations: an integrative study
Authors: Añaña Edar da Silva , Rodrigues Raphaella Costa , Flores Luiz Carlos da Silva
Published: April 2018

Purpose

The purpose of this paper is to address a new method to evaluate the competitiveness of tourist destinations based on competitive performance from the consumers’ perspective. The main objective is to assess the sources of relative strength and weakness perceived in a destination, and to evaluate its performance vis-à-vis to the main competitors identified by tourists through measurement indexes.

Design/methodology/approach

The strengths and weaknesses of the focal destination were identified by plotting 12 tourism-specific variables (attractors) and 12 business-related variables in importance-performance matrix (IPA) grids. The set of destinations identified as “the main competitors” were built according to the frequency they were mentioned, and the indicators of competitiveness were estimated by averaging variables representing dimensions identified by exploratory-confirmatory factor analysis. The variables were aggregated into dimensions to permit comparisons in relation to the main competitors.

Findings

The results suggest that tourism-specific variables converge to “tourist attractions” and “conviviality,” and that business-related variables converge into “accessibility,” “infrastructure” and “macrostructure.” The competitiveness against competition was evaluated twice: by using an IPA grid to evaluate competition against “all others,” and by comparing the factors of performance across the most cited competitors. The results show that the focal destination surpasses most of its main competitors in conviviality, but has some deficiencies in tourist attractions, and that dimensions representing the business-related variables fit in the middle.

Research limitations/implications

The authors acknowledge that competitive performance, used as surrogate for competitiveness, is fairly limited once it does not consider the supply side potential forces that also influence the destination competitiveness (DC) at large. But although limited to the demand side, the proxy used to assess (DC) is in accordance with previous literature.

Practical implications

The results have high value to DMO managers, especially to those ones involved in developing tourism attractions.

Originality/value

This research advances over previous works: by identifying the nearest competitors of a destination; and by representing the competitive distance between the focal destination and its main competitors.
Financial institution ties and survival of small commercial poultry farms (SCPFs) in Ghana
Authors: Acheampong George
Published: April 2018

Purpose

The purpose of this study was to understand the usefulness of financial institution class ties in small commercial poultry farms’ (SCPFs’) survival in Ghana.

Design/methodology/approach

The study uses data from a network survey with associated attribute data on poultry small- and medium-sized enterprises. The data were collected in two waves between January 2014 and March 2015. Survival is estimated using a lagged probit model.

Findings

It was found that the survival rate of SCPFs is influenced by ties to universal banks and cooperative credit unions that have a positive effect while those with ties to savings and loans companies have a reduced survival probability.

Originality/value

The findings of the study make a significant contribution to the agricultural enterprise financing literature showing the relevance of the different financial institution types in the continued survival of agricultural SCPFs.
Patterns and perception of alcohol drinking among the Lahu people, Northern Thailand
Authors: Detpitukyon Sudkhed , Apidechkul Tawatchai , Sunsern Rachanee , Anuwatnonthakate Amornrat , Singhhorn Onnalin , Putsa Bukhari , Thutsanti Phitnaree
Published: April 2018

Purpose

The purpose of this paper is to understand the pattern and perception of alcohol drinking among the Lahu people in northern Thailand.

Design/methodology/approach

A qualitative method was used to elicit information on the patterns and perceptions of alcohol drinking amongst the Lahu tribespeople. Question guidelines had been developed from literature reviews and approved by three experts in the field of public health and alcohol studies. A total of 21 participants of different ages and sexes from 3 separate Lahu villages were invited to provide information. All interviews were taped and transcribed before analysis. A content analysis was used.

Findings

Lahu people begin alcohol consumption at an average of 12 years, with males usually beginning before females of the same age. Consuming alcohol is perceived to be a sign of adulthood and is also used as a means of gaining social acceptance from others in the community. Alcohol is consumed throughout the year with young and old, male and females, describing varied reasons for drinking. Income, parental behavior, and peer pressure contributes to the onset of alcohol drinking among young Lahu people. Several factors contributed to the use of alcohol among the Lahu people such as sex, age, occupation and income, peer pressure, taste and price as well as cultural adaptations amongst the farming community that play a significant role in the frequency of alcohol consumption amongst the Lahu community.

Originality/value

The results should support the development of peer education on the negative impact of alcohol use among the young people, and development of a community agreement on reducing excessive alcohol use in the Lahu community should be implemented.
Influence of emotional regulation on successful aging among Thai older adults
Authors: Tuicomepee Arunya , Suttiwan Panrapee , Watakakosol Rewadee , Ngamake Sakkaphat T. , Iamsupasit Sompoch
Published: April 2018

Purpose

Successful aging represents a positive development in older adults. The emphasis on aging well has sought to understand resources such as emotional regulation that facilitates healthy and happy aging. The purpose of this paper is to investigate the impact of two common emotional regulation strategies (i.e. cognitive reappraisal and expressive suppression) on successful aging among Thai older adults.

Design/methodology/approach

The participants selected for this paper were 150 older adults living in Bangkok and adjacent areas. Their mean age was 69.7 (±6.7) years old. Instruments were the Successful Aging Inventory and Emotion Regulation Questionnaire. Each participant voluntarily completed an individual self -reported questionnaire.

Findings

The results revealed that the two emotional regulation strategies (cognitive reappraisal and expressive suppression) have collectively explained 6 percent of the variance of successful aging. The cognitive reappraisal strategy was a sole significant predictor (β=0.20).

Originality/value

Promoting emotional regulation strategies in particular a cognitive reappraisal strategy among Thai older adults can facilitate their cognitive functioning, and their successful aging.
Effectiveness of hand foot mouth disease prevention and control measures between high and low epidemic areas, Northern Thailand
Authors: Sittisarn Siriyaporn , Wongnuch Pilasinee , Laor Pussadee , Inta Chadaporn , Apidechkul Tawatchai
Published: April 2018

Purpose

Hand foot mouth disease (HFMD) is an emerging disease caused by Enterovirus. HFMD usually occurs in South-East Asian countries including Thailand. Thailand has been indicated as one of the countries having high epidemic rate in children less than five years of age, particularly in the northern regions. The paper aims to discuss this issue.

Design/methodology/approach

A qualitative method was used to extract information from 48 informants from two different areas; high and low epidemic areas of HFMD. Question guidelines were developed from literature review and viewed by three external experts in the field before use. Interviews took place in a private and confidential room. Each interview lasted approximately 50 minutes.

Findings

There are no policies regarding HFMD control in both high and low epidemic areas of HFMD. The staff at sub-district local government level did not have the necessary qualifications for HFMD control. Additionally, staff were not stable, and there was a lack of a disease control team. Antiseptics for cleaning day care centers (DCC) were not effective for disease control; most DCC use Dettol®, soap, dishwashing liquid, detergent and water for cleaning the environment. These antiseptics do not include chlorine making it ineffective in destroying the virus.

Originality/value

The sub-district local government should be concerned about HFMD control; the staff should have the necessary qualifications suitable for disease control. Standard and practical HFMD control guideline should be set up and used in DCC.
Determinants of compliance with child immunization among mothers of children under five years of age in Ekiti State, Nigeria
Authors: Konwea Patience Esohe , David Funmilayo Alice , Ogunsile Seyi Elizabeth
Published: April 2018

Purpose

Vaccine preventable diseases are major threats to the health and well-being of children under five years of age. They contribute a great deal to childhood illnesses and disabilities, and are accountable for a high percentage of childhood mortality worldwide. In Nigeria, the government has made a lot of effort to provide immunizations against these childhood diseases. It is however sad to note that many children still do not complete their routine immunization. The purpose of this paper is to determine factors which influence mothers’ compliance with childhood immunization.

Design/methodology/approach

This was a descriptive study carried out among 600 mothers of under-five children randomly selected from nine postnatal clinics in Ekiti State between January and August 2016. A self-structured validated questionnaire containing items to explore demographic characteristics of respondents, compliance with child immunization (Cronbach’s α=0.92) and determinants of compliance (Cronbach’s α=0.83) was the instrument for data collection. Multiple regression analysis was used to identify determinants of mothers’ compliance with childhood immunization.

Findings

The level of compliance of mothers with childhood immunization was high (80 percent). The two factors which contributed significantly to mothers’ compliance were the mothers’ knowledge of childhood immunization (β weight= 0.243) and mothers’ educational status (β weight=0.169). Mothers with tertiary education had the highest level of compliance (76.8 percent).

Originality/value

Having good knowledge of childhood immunization and a high educational status positively influence a mothers’ compliance with child immunization.
Efficacy of district tuberculosis co-ordinating team on health service performance for suspected TB patient in district hospital
Authors: Tangsawad Sasithorn , Taneepanichskul Surasak
Published: April 2018

Purpose

The purpose of this paper is to study the efficacy of a district tuberculosis (TB) co-ordinating team on health service performance for suspected TB patients in a district hospital in northeastern Thailand.

Design/methodology/approach

A comparison study of pre- and post-evaluations of TB system improvement was conducted in a district hospital in northeastern Thailand between October 2016 and June 2017. Data collection reviewed the record of suspected TB cases reported in the district hospital in the past nine months as a base line for describing the health service performance in term of received investigation for TB diagnosis. Participants from a TB clinic, district health office and health center set up a TB co-ordinating team to explore situations and systematic gaps. The TB co-ordinating team gave recommendations of health service performance for suspected TB patients over a nine-month period. Records of suspected TB cases health service performance were collected nine months after intervention. Data analysis by descriptive statistics and to test the effect of intervention was performed.

Findings

The records from 324 and 379 suspected TB cases reported in the hospital from the 9 months preceding and 9 months, respectively, after intervention were reviewed. A TB co-ordinating team was set up to improve the system and health service performance in terms of investigation for TB diagnosis. The results revealed that health service performance in terms of complete microscopy and investigation in both chest radiography and microscopy increased after intervention. When comparing between pre- and post-intervention, suspected cases received both chest radiography and microscopy in 176 cases and 283 cases, respectively (p-value=0.001). There were 27 cases diagnosed for smear positive TB in pre-intervention and 51 cases diagnosed in post-intervention (p-value=0.011). There were 21 cases pre- and 36 cases post-intervention that had referral documents from health center with no statistically significant difference.

Originality/value

The TB co-ordinating team had the role to improve health service performance for suspected TB cases to enroll in investigation process for increase TB diagnosis in district hospital.
The comparison of causal relationships of job stress between Thai immigrant employees with and without rearing their aging parents
Authors: Kaewanuchit Chonticha , Sawangdee Yothin
Published: April 2018

Purpose

The occupational stress is a disadvantage resulting in mental health illnesses that have been found when looking at those migrants who were young adults and migrated to work in the urban areas, leaving behind their aging parents to live alone at home. The purpose of this paper is to compare the causal relationships of job stress between Thai immigrant employees with and without rearing aging parents.

Design/methodology/approach

The research was a cross-sectional survey. The sample for this study included 600 Thai immigrant employees (300 cases per group) in 2016. Measures included individual characteristics, working conditions, and a Thai Job Content Questionnaire (Thai-JCQ) on related job stress. The model was verified using a path model by Mplus software.

Findings

The distance traveled between the house and the workplace, wages, working conditions had a direct effect on job stress. Working conditions among Thai immigrants employees with rearing aging parents had the most direct effect on job stress with a standardized regression weight of 0.552 (p-value <0.05) as well as working conditions among their without rearing aging parents had the most direct effect on job stress with a standardized regression weight of −0.292.

Originality/value

This research demonstrated that working conditions were an important factor.
Corporate values from a personal perspective
Authors: Illes Katalin , Vogell Christiane
Published: April 2018

Purpose

The paper aims to analyse organisational values from a personal perspective. The purpose was to explore how employees learn about corporate values and how they relate to these values. The motivation has been one of discovery of current practices in businesses, with a strong focus on corporate values and their effects on employees.

Design/methodology/approach

The authors offer a review of the key definitions and main theoretical frameworks of values. Four case studies provide empirical data to establish some understanding of how values are identified and the extent to which they are translated into behaviours and attitudes in the workplace. The paper combines an overview of literature on values and semi-constructed telephone interviews with 26 interviewees from four organisations about corporate and individual values.

Findings

Values are positively related to, and central to the concept of the self, and are distinct from norms. Both the literature review and the multiple case studies’ empirical findings suggest that values are worth striving for and successful embedding of them requires a “culture of sharing”. Without the culture of sharing corporate values will not penetrate the organisation or have any meaningful impact on behaviour.

Originality/value

The paper highlights the importance of considering corporate values from a personal perspective. Organisations wanting to strengthen corporate values need to engage in conversations about values regularly across the organisation. Leaders need to be part of these discussions without dominating or forcefully influencing them.
In vivo effect of a TLR5 SNP (C1205T) on Salmonella enterica serovar Typhimurium infection in weaned, specific pathogen‐free Landrace piglets
Authors: Muneta Yoshihiro , Arai Nobuo , Yakabe Yoko , Eguchi Masahiro , Shibahara Tomoyuki , Sakuma Akiko , Shinkai Hiroki , Uenishi Hirohide , Hirose Kensuke , Akiba Masato
Published: April 2018

Toll‐like receptor 5 is a pattern‐recognition receptor for bacterial flagellin. We previously reported that a single nucleotide polymorphism (SNP) of swine TLR5, C1205T, impairs recognition of Salmonella typhimurium (ST) flagellin and ethanol‐killed Salmonella Choleraesuis (SC). In the present study, weaned, specific pathogen‐free (SPF) Landrace piglets with CC, CT or TT genotypes were orally infected with ST (L‐3569 strain) to determine the effect of this specific SNP on ST infection in vivo. Eighteen ST‐infected piglets (six each with CC, CT, or TT) exhibited fever and diarrhea for 1 week after infection. TT piglets had the longest duration of fever. TT piglets had the greatest mean diarrhea score during the experimental period, followed by CT and CC piglets. Fecal ST shedding was greater in CT and TT pigs than CC pigs from 2 days after infection. Serum haptoglobin concentration increased in ST‐infected piglets and to greater extents in CT and TT pigs than CC pigs. Daily weight gain was lower in infected pigs, particularly TT piglets, than control pigs. To the best of our knowledge, this study is the first to demonstrate that impairment of TLR recognition affects pig susceptibility to disease in vivo. Thus, piglets with the T allele of swine TLR5 (C1205T) exhibit impaired resistance to ST infection. Furthermore, elimination of the T allele of this SNP from Landrace pigs would lead to enhancement of their resistance to ST infection.
Generalisation and specialisation in hoverfly (Syrphidae) grassland pollen transport networks revealed by DNA metabarcoding
Authors: Lucas Andrew , Bodger Owen , Brosi Berry J. , Ford Col R. , Forman Dan W. , Greig Carolyn , Hegarty Matthew , Neyland Penelope J. , de Vere Natasha
Published: April 2018

Pollination by insects is a key ecosystem service and important to wider ecosystem function. Most species‐level pollination networks studied have a generalised structure, with plants having several potential pollinators, and pollinators in turn visiting a number of different plant species. This is in apparent contrast to a plant's need for efficient conspecific pollen transfer.

The aim of this study was to investigate the structure of pollen transport networks at three levels of biological hierarchy: community, species and individual. We did this using hoverflies in the genus Eristalis, a key group of non‐Hymenopteran pollinators.

We constructed pollen transport networks using DNA metabarcoding to identify pollen. We captured hoverflies in conservation grasslands in west Wales, UK, removed external pollen loads, sequenced the pollen DNA on the Illumina MiSeq platform using the standard plant barcode rbcL, and matched sequences using a pre‐existing plant DNA barcode reference library.

We found that Eristalis hoverflies transport pollen from 65 plant taxa, more than previously appreciated. Networks were generalised at the site and species level, suggesting some degree of functional redundancy, and were more generalised in late summer compared to early summer. In contrast, pollen transport at the individual level showed some degree of specialisation. Hoverflies defined as “single‐plant visitors” varied from 40% of those captured in early summer to 24% in late summer. Individual hoverflies became more generalised in late summer, possibly in response to an increase in floral resources. Rubus fruticosus agg. and Succisa pratensis were key plant species for hoverflies at our sites

Our results contribute to resolving the apparent paradox of how generalised pollinator networks can provide efficient pollination to plant species. Generalised hoverfly pollen transport networks may result from a varied range of short‐term specialised feeding bouts by individual insects. The generalisation and functional redundancy of Eristalis pollen transport networks may increase the stability of the pollination service they deliver.
Functional traits and environmental characteristics drive the degree of competitive intransitivity in European saltmarsh plant communities
Authors: Ulrich Werner , Kubota Yasuhiro , Piernik Agnieszka , Gotelli Nicholas J.
Published: April 2018

Competitive intransitivity, the existence of loops in competitive hierarchies, is one mechanism that can promote the local coexistence of competitors and maintain high local species diversity, although its prevalence and importance remain largely unknown. A full understanding of local community assembly needs knowledge of how transitive and intransitive competitive interactions are linked to species functional traits and the strength of biotic and abiotic filters.

We apply a recently developed statistical tool to quantitative data on central European inland saltmarsh plant communities to infer causal relationships between soil characteristics, species occurrences and functional traits, and we estimated coefficients of competition.

We found a predominance of intransitive competitive hierarchies. The proportion of such hierarchies was positively correlated with local species richness and compositional variability. Average soil characteristics were not correlated with competitive intransitivity, whereas high soil pH and the high variability in local pH and soil salinity decreased the overall impact of competition on community composition. In pairwise comparisons of species, dissimilarity in morphology, resource demand and reproductive phenology was significantly negatively correlated with differences in competitive performance, while higher environmental dissimilarity was particularly linked to intermediate degrees of competitive superiority.

Our results suggest that habitat filtering for similar traits might intensify competitive interactions, but might also give rise to intransitive competitive loops that subsequently promote species coexistence and permit species’ functional equivalence. Intransitive competition appears to increase local diversity and small scale‐species turnover. The observed local differences in competitive structures suggest frequent competitive plasticity and context‐dependent competitive interactions. Finally, our results support the view that local abundance distributions can be used to infer the strength and outcome of competitive interactions.

Synthesis. Our results confirm that intransitive competitive interactions might be a strong force structuring local plant communities. Intransitivity needs to be considered when studying plant community assembly and species co‐existence.
Emergence of weak‐intransitive competition through adaptive diversification and eco‐evolutionary feedbacks
Authors: Gallien Laure , Landi Pietro , Hui Cang , Richardson David M.
Published: April 2018

Indirect biotic interactions—such as intransitive competition—are increasingly recognized as being important in shaping ecological patterns in natural systems. Over long time‐scales, such indirect interactions may affect the evolution of species phenotypes, which in turn can modify these interactions, thereby begetting eco‐evolutionary feedbacks. If indirect intransitive interactions can emerge in situ during lineage diversification, they could profoundly affect species’ phenotypic diversity, temporal stability, and subsequent diversification rates.

We address these questions by investigating the conditions under which indirect intransitive competition can emerge from a lineage diversifying in sympatry. We use an adaptive dynamics model to study the ecological and evolutionary properties of this lineage under different scenarios where competition for resources between phenotypes varies in strength and (a)symmetry.

Results show that weak‐intransitive competition can emerge during the sympatric diversification of a single lineage. “Weak‐intransitivity” here refers to situations where species interactions are not perfectly transitive, that is, there is no strict hierarchy in species competitive abilities. The strength of such weak‐intransitivity increases when the competition between phenotypes increases in strength and asymmetry. The strength of intransitivity also correlates with other system properties. We notably found that the strength of intransitivity increases with the number of phenotypes, and that greater intransitivity correlates with the evolution of greater functional trait divergences between phenotypes, greater resistance to invasion by new phenotypes but lower resistance to disturbances as well as slower evolutionary rates.

Synthesis. This theoretical exploration of the evolution of intransitive competition provides the first formal bridge between the ecological and evolutionary aspects of intransitive competition. We show that, when competitive interactions are strong enough, weak‐intransitive competition is more likely to emerge through adaptive diversification than from a random community assembly. Intransitive competition is, therefore, not only restricted to between‐species interactions but can also function as a regulator of diversification within species, thereby affecting lineage functional diversity, and ecological and evolutionary stability.
At, with and beyond risk: expectations of living with the possibility of future dementia
Authors: Milne Richard , Diaz Ana , Badger Shirlene , Bunnik Eline , Fauria Karine , Wells Katie
Published: April 2018

Biomedical research aimed at the development of therapies for chronic and late‐onset conditions increasingly concentrates on the early treatment of symptom‐less disease. This broad trend is evidenced in prominent shifts in contemporary dementia research. Revised diagnostic criteria and new approaches to clinical trials propose a focus on earlier stages of disease and prompt concerns about the implications of communicating test results associated with the risk of developing dementia when no effective treatments are available. This article examines expectations of the implications of learning test results related to dementia risk, based on focus group research conducted in the UK and Spain. It points to the extended social and temporal aspects of the dementia risk experience. Three key dimensions of this risk experience are elaborated: living ‘at risk’, represented in efforts to reduce risk and plan for the future; ‘with risk’, through vigilance towards cognitive health and earlier or prolonged contact with healthcare services; and finally, ‘beyond risk’ through a cessation of the self in its current social, legal and financial form. A virtual abstract of this paper can be viewed at: https://www.youtube.com/channel/UC_979cmCmR9rLrKuD7z0ycA
Patterns of statin use and long‐term adherence and persistence among older adults with diabetes
Authors: Ofori‐Asenso Richard , Ilomäki Jenni , Tacey Mark , Zomer Ella , Curtis Andrea J. , Bell J. Simon , Zoungas Sophia , Liew Danny
Published: April 2018

Background

Statins reduce the risk of cardiovascular disease in patients with diabetes. This study examined the prevalence of statin use and assessed long‐term adherence and persistence among people aged ≥65 years with diabetes.

Methods

Pharmaceutical Benefits Scheme data covering a 10% random sample of the Australian population were analyzed. Among older adults with diabetes, the yearly prevalence of statin use was compared via Poisson regression modeling using 2006 as the reference year. A cohort of 7400 new statin users (mean age 72.9 years; 46.2% female) was followed longitudinally. Adherence was assessed via the proportion of days covered (PDC). Statin discontinuation was defined as the first ≥90 days without statin coverage.

Results

The prevalence of statin use increased from 52.0% in 2006 to 71.2% in 2016 (age and sex‐adjusted rate ratio 1.37; 95% confidence interval 1.33–1.41). No gender differences in statin use were observed, but the likelihood of being dispensed statin decreased with increasing age. Among the longitudinal cohort, the proportion adherent (PDC ≥0.80) decreased from 54.0% at 6 months to 37.0% at 9 years. Over a mean follow‐up of 4.9 years, 66.8% discontinued, and the likelihood of stopping statin medication within the first year was 42.7%. No age or gender differences in statin discontinuation were evident.

Conclusions

Statin use has increased among older adults with diabetes. However, adherence is low and discontinuation is high. Further investigations into the factors associated with non‐adherence or discontinuation of statins are important so as to optimize statin use towards achieving the intended cardiovascular benefits among older people with diabetes.
Scene‐specific convolutional neural networks for video‐based biodiversity detection
Authors: Weinstein Ben G.
Published: April 2018

Finding, counting and identifying animals is a central challenge in ecology. Most studies are limited by the time and cost of fieldwork by human observers. To increase the spatial and temporal breadth of sampling, ecologists are adopting passive image‐based monitoring approaches. While passive monitoring can expand data collection, a remaining obstacle is finding the small proportion of images containing ecological objects among the majority of frames containing only background scenes.

I proposed a scene‐specific convolutional neural network for detecting animals of interest within long duration time‐lapse videos. Convolutional neural networks are a type of deep learning algorithm that have recently made significant advances in image classification.

The approach was tested on videos of floral visitation by hummingbirds. Despite low frame rates, poor image quality, and complex video conditions, the model correctly classified over 90% of frames containing hummingbirds. Combining motion detection and image classification can substantially reduce the time investment in scoring images from passive monitoring studies.

These results underscore the promise of deep learning to lead ecology into greater automation using passive image analysis. To help facilitate future applications, I created a desktop executable that can be used to apply pre‐trained models to videos, as well as reproducible scripts for training new models on local and cloud environments.
Development of a Tissue‐Engineered Artificial Ligament: Reconstruction of Injured Rabbit Medial Collateral Ligament With Elastin‐Collagen and Ligament Cell Composite Artificial Ligament
Authors: Hirukawa Masaki , Katayama Shingo , Sato Tatsuya , Inoue Kota , Niwa Kosuke , Ito Naoya , Hattori Tetsuya , Hosoi Takashi , Unno Hironori , Suzuki Yoshiaki , Hasegawa Masahiro , Miyamoto Keiichi , Horiuchi Takashi
Published: April 2018

Ligament reconstruction using a tissue‐engineered artificial ligament (TEAL) requires regeneration of the ligament‐bone junction such that fixation devices such as screws and end buttons do not have to be used. The objective of this study was to develop a TEAL consisting of elastin‐coated polydioxanone (PDS) sutures covered with elastin and collagen fibers preseeded with ligament cells. In a pilot study, a ring‐type PDS suture with a 2.5 mm (width) bone insertion was constructed with/without elastin coating (Ela‐coat and Non‐coat) and implanted into two bone tunnels, diameter 2.4 mm, in the rabbit tibia (6 cases each) to access the effect of elastin on the bond strength. PDS specimens taken together with the tibia at 6 weeks after implantation indicated growth of bone‐like hard tissues around bone tunnels accompanied with narrowing of the tunnels in the Ela‐coat group and not in the Non‐coat group. The drawout load of the Ela‐coat group was significantly higher (28.0 ± 15.1 N, n = 4) than that of the Non‐coat group (7.6 ± 4.6 N, n = 5). These data can improve the mechanical bulk property of TEAL through extracellular matrix formation. To achieve this TEAL model, 4.5 × 106 ligament cells were seeded on elastin and collagen fibers (2.5 cm × 2.5 cm × 80 µm) prior to coil formation around the elastin‐coated PDS core sutures having ball‐shape ends with a diameter of 2.5 mm. Cell‐seeded and cell‐free TEALs were implanted across the femur and the tibia through bone tunnels with a diameter of 2.4 mm (6 cases each). There was no incidence of TEAL being pulled in 6 weeks. Regardless of the remarkable degradation of PDS observed in the cell‐seeded group, both the elastic modulus and breaking load of the cell‐seeded group (n = 3) were comparable to those of the sham‐operation group (n = 8) (elastic modulus: 15.4 ± 1.3 MPa and 18.5 ± 5.7 MPa; breaking load: 73.0 ± 23.4 N and 104.8 ± 21.8 N, respectively) and higher than those of the cell‐free group (n = 5) (elastic modulus: 5.7 ± 3.6 MPa; breaking load: 48.1 ± 11.3 N) accompanied with narrowed bone tunnels and cartilage matrix formation. These data suggest that elastin increased the bond strength of TEAL and bone. Furthermore, our newly developed TEAL from elastin, collagen, and ligament cells maintained the strength of the TEAL even if PDS was degraded.