bluuebunny/crossref_metadata_2025 huggingface dataset:
Co-regulation of hormone receptors, neuropeptides, and steroidogenic enzymes across the vertebrate social behavior network
Authors: Horton Brent M. , Ryder T. Brandt , Moore Ignacio T. , Balakrishnan Christopher N.
Published: October 2018

The vertebrate basal forebrain and midbrain contain a set of interconnected nuclei that control social behavior. Conserved anatomical structures and functions of these nuclei have now been documented among fish, amphibians, reptiles, birds and mammals, and these brain regions have come to be known as the vertebrate social behavior network (SBN). While it is known that nuclei (nodes) of the SBN are rich in steroid and neuropeptide activity linked to behavior, simultaneous variation in the expression of neuroendocrine genes among several SBN nuclei has not yet been described in detail. In this study, we use RNA-seq to profile gene expression across seven brain regions representing five nodes of the vertebrate SBN in a passerine bird, the wire-tailed manakin Pipra filicauda. Using weighted gene co-expression network analysis (WGCNA), we reconstructed sets of coregulated genes, revealing striking patterns of variation in neuroendocrine gene expression across the SBN. We describe regional expression variation networks comprising a broad set of hormone receptors, neuropeptides, steroidogenic enzymes, catecholamines, and other neuroendocrine signaling molecules. Our findings highlight how heterogeneity of brain gene expression across the SBN can provide functional insights into the neuroendocrine and genetic mechanisms that underlie vertebrate social behavior.
RefSoil+: A reference for antimicrobial resistance genes on soil plasmids
Authors: Dunivin TK , Choi J , Howe AC , Shade A
Published: October 2018

Plasmids harbor transferable genes that contribute to the functional repertoire of microbial communities, yet their contributions to metagenomes are often overlooked. Environmental plasmids have the potential to spread antibiotic resistance to clinical microbial strains. In soils, high microbiome diversity and high variability in plasmid characteristics present a challenge for studying plasmids. To improve understanding of soil plasmids, we present RefSoil+, a database containing plasmid sequences from 922 soil microorganisms. Soil plasmids were relatively larger than other described plasmids, which is a trait associated with plasmid mobility. There was no relationship between chromosome size and plasmid size or number, suggesting that these genomic traits are independent in soil. Soil-associated plasmids, but not chromosomes, had fewer antibiotic resistance genes than other microorganisms. These data suggest that soils may offer limited opportunity for plasmid-mediated transfer of described antibiotic resistance genes. RefSoil+ can serve as a baseline for the diversity, composition, and host-associations of plasmid-borne functional genes in soil, a utility that will be enhanced as the database expands. Our study improves understanding of soil plasmids and provides a resource for assessing the dynamics of the genes that they carry, especially genes conferring antibiotic resistances.

Importance

Soil-associated plasmids have the potential to transfer antibiotic resistance genes from environmental to clinical microbial strains, which is a public health concern. A specific resource is needed to aggregate knowledge of soil plasmid characteristics so that the content, host-associations, and dynamics of antibiotic resistance genes can be assessed and then tracked between the environment and the clinic. Here, we present RefSoil+, a database of soil-associated plasmids. RefSoil+ presents a contemporary snapshot of antibiotic resistance genes in soil that can serve as a reference as novel plasmids and transferred antibiotic resistances are discovered. Our study broadens our understanding of plasmids in soil and provides a community resource for investigating clinic-environment dynamics of important plasmid-associated genes, including antibiotic resistance genes.
Structural basis of HEAT-kleisin interactions in the human condensin I subcomplex
Authors: Hara Kodai , Kinoshita Kazuhisa , Migita Tomoko , Murakami Kei , Shimizu Kenichiro , Takeuchi Kozo , Hirano Tatsuya , Hashimoto Hiroshi
Published: October 2018

ABSTRUCT

Condensin I is a multi-protein complex that plays an essential role in mitotic chromosome assembly and segregation in eukaryotes. It is composed of five subunits: two SMC (SMC2 and SMC4), a kleisin (CAP-H) and two HEAT-repeat (CAP-D2 and -G) subunits. Although it has been shown that balancing acts of the two HEAT-repeat subunits enable this complex to support dynamic assembly of chromosomal axes in vertebrate cells, its underlying mechanisms remain poorly understood. Here, we report the crystal structure of a human condensin I subcomplex comprising hCAP-G and hCAP-H. hCAP-H binds to the concave surfaces of a harp-shaped HEAT repeat domain of hCAP-G. A physical interaction between hCAP-G and hCAP-H is indeed essential for mitotic chromosome assembly recapitulated in Xenopus egg cell-free extracts. Furthermore, this study reveals that the human CAP-G-H subcomplex has the ability to interact with not only a double-stranded DNA, but also a single-stranded DNA, implicating potential, functional divergence of the vertebrate condensin I complex in mitotic chromosome assembly.
The ATR kinase of Trypanosoma brucei links DNA damage signalling and monoallelic control of surface antigen gene expression during antigenic variation
Authors: Black Jennifer Ann , Crouch Kathryn , Lemgruber Leandro , Lapsley Craig , Dickens Nicholas , Mottram Jeremy C. , McCulloch Richard
Published: October 2018

To evade mammalian immunity, Trypanosoma brucei switches the variant surface glycoprotein (VSG) expressed on its surface. Key to this reaction are controls exerted to ensure only one of many subtelomeric multigene VSG expression sites are transcribed at a time. DNA repair activities have to date been implicated only in catalysis of VSG switching by recombination, not transcriptional control. However, how VSG switching is signalled to guide the appropriate reaction, or to integrate switching into parasite growth, is unknown. Here we show that loss of ATR, a DNA damage signalling protein kinase, is lethal and causes increased nuclear genome lesions. ATR depletion also causes expression of mixed VSGs on the cell surface, increased transcription of genes from silent expression sites, and altered localisation of RNA Polymerase I and VEX1, factors involved in VSG transcription. The work therefore reveals that VSG expression control is mediated by a nuclear DNA damage signalling factor.
Evolution of influenza genome diversity during infection in immunocompetent patients
Authors: Pichon Maxime , Simon Bruno , Valette Martine , Bal Antonin , Picard Caroline , Escuret Vanessa , Ottmann Michèle , Gillet Yves , Ader Florence , Lina Bruno , Josset Laurence
Published: October 2018

Introduction

Minor frequency viruses play many important roles during viral infection that cannot be explained by the consensus sequence alone. In influenza, immunosuppressed individuals appear to generate numerous viral variants, leading to subpopulations with important role in infection. The objective of the present study was to describe viral diversification over time in immunocompetent patients during influenza virus infection.

Methods

All clinical records of patients admitted to the Lyon university hospital (Lyon, France) during the influenza infection epidemics of the 2010-2015 period and sampled at least twice during their clinical management were retrospectively analyzed. To estimate performance of the sequencing procedures, well-characterized plasmids containing each of the 8 segments of influenza viruses were used as quality controls. Diversity, i.e. the number of validated single nucleotide variants, was analyzed to compare characteristics over time and according to clinical severity (mild, severe with neurological complications, severe with respiratory complications).

Results

After validation on quality controls (n=51), and verification of possible confusion bias, a 5%-threshold of detection was applied to clinical viral sequences (n=29). At this threshold, amino-acid coordinates (n=183/4,246, 4.31%) were identified as having at least one mutation during clinical course, independently of the clinical severity. Considering a threshold of 4 days of symptoms, as a limit for early and late sampling, diversity was significantly higher in late samples for the mild group, compared to both early mild and severe groups (p<0.05). At a single-segment scale, for PB2-coding segment, diversity was significantly higher in early samples of the neurological group than in both early and late samples in the respiratory group and for late samples in the mild group (p<0.05). For the NS1-coding segment, significant differences were observed between initial diversity of mild and severe patients, as for early and late samples in mild patients (p<0.01). Discussion. This study is the first describing diversity through time, associating biological and clinical information during viral diversification, during the infection of an immunocompetent human host. This latter opens a large field of investigation in infectious disease management using next-generation sequencing and suggest development of new therapies, focusing on non-antigenic viral properties, in non-vaccine fields of research
Combined strategy of siRNA and osteoclast actin cytoskeleton automated imaging to identify novel regulators of bone resorption shows a non-mitotic function for anillin
Authors: Maurin Justine , Morel Anne , Hassen-Khodja Cedric , Vives Virginie , Jurdic Pierre , Machuca-Gayet Irma , Blangy Anne
Published: October 2018

Osteoclasts are the main cells responsible for the resorption of mineralized extracellular matrices. They are the major targets for anti-resorptive therapies to manage osteoporosis, a major public health problem. Osteoclasts are giant multinucleated cells that can organize their a unique adhesion structure based on a belt of podosomes, which is the keystone of the bone resorption apparatus. We combined differential transcriptomics and siRNA screening approaches to get a broader view of cytoskeletal regulators that participate in the control of osteoclast cytoskeleton and identify novel regulators of bone resorption by osteoclasts. We identified 20 new candidate regulators of osteoclasts cytoskeleton including Fkbp15, Spire1, Tacc2 and RalA, for which we confirmed they are necessary for proper organization of the podosome belt. We also showed that Anillin, well known for its role during cytokinesis, is essential in osteoclasts for correct podosome patterning and efficient bone resorption. In particular, Anillin controls the levels of the GTPase RhoA, a known regulator of osteoclast cytoskeleton and resorption activity. Finally, we set up and validated an automated imaging strategy based on open-source software for automatic and objective measurement of actin cytoskeleton organization in osteoclasts. We provide these pipelines that are useful to automatically assess the effect of collections of siRNAs or chemical compounds on osteoclast cytoskeleton or differentiation.
Posterior axis formation requiresDlx5/Dlx6expression at the neural plate border
Authors: Narboux-Neme Nicolas , Ekker Marc , Levi Giovanni , Heude Églantine
Published: October 2018

Neural tube defects (NTDs), one of the most common birth defects in human, present a multifactorial etiology with a poorly defined genetic component. TheDlx5andDlx6bigenic cluster encodes two evolutionary conserved homeodomain transcription factors, which are necessary for proper vertebrate development. It has been shown thatDlx5/6genes are essential for anterior neural tube closure, however their role in the formation of the posterior structures has never been described. Here, we show thatDlx5/6expression is required during vertebrate posterior axis formation.Dlx5presents a similar expression pattern in neural plate border cells during posterior neurulation of zebrafish and mouse.Dlx5/6-inactivation in the mouse results in a phenotype reminiscent of NTDs characterized by open thoracic and lumbar vertebral arches and failure of epaxial muscle formation at the dorsal midline. Thedlx5a/6azebrafish morphants present posterior NTDs associated with abnormal delamination of neural crest cells showing altered expression of cell adhesion molecules and defects of motoneuronal development. Our findings provide new molecular leads to decipher the mechanisms of vertebrate posterior neurulation and might help to gather a better understanding of human congenital NTDs etiology.
More Insights into the Relation between DNA Ionization Potentials, Single Base Substitutions and Pathogenic Mutations
Authors: Pucci Fabrizio , Rooman Marianne
Published: October 2018

It is nowadays clear that the single base substitutions that occur in the human genome, of which some lead to pathogenic conditions, are non-random and influenced by their flanking nucleobase sequences. However, despite recent progress, the understanding of these “non-local” effects is still far from being achieved. In order to advance this problem, we analyzed the relationship between the base mutability in gene regions and the electron hole transport along the DNA base stacks, as it is one of the mechanisms that have been suggested to contribute to these effects. More precisely, we studied the connection between the observed frequency of single base substitutions and the vertical ionization potential of the base and its flanking sequence, estimated using MP2/6-31G*ab initioquantum chemistry calculations. We found a good correlation between the two quantities, whose sign depend on whether SBS is in an exon, an intron or an untranslated region. Interestingly, the correlation appears to be higher for synonymous than for missense mutations, and when considering the flanking sequence of the substituted base in the 3’ rather than in the 5’ direction. A weaker but still statistically significant correlation it found between the ionization potentials and the pathogenicity of the base substitutions. Moreover, pathogenicity is also preferentially associated with larger changes in ionization potentials upon base substitution. With this analysis we gained new insights into the complex biophysical mechanisms that are at the basis of mutagenesis and pathogenicity, and supported the role of electron-hole transport in these matters.
Epigenetic transmission of cardiometabolic risk in offspring discordant for maternal gestational metabolic fitness
Authors: Guénard Frédéric , Marceau Simon , Simard Serge , Kral John G , Vohl Marie-Claude , Marceau Picard
Published: October 2018

OBJECTIVE

Diabesity during gestation predisposes offspring to lifetime cardiometabolic risk. We demonstrated that maternal biliopancreatic diversion surgery (BPD) improved metabolic fitness and pregnancies reducing cardiometabolic risk in siblings born after (AMS) compared to before maternal surgery (BMS). We found differential methylation of inflammatory and glucoregulatory genes in peripheral blood cell DNA in offspring and in mothers after BPD compared to preoperative “control” women. Here we study offspring trajectories of cardiometabolic risk markers and determine persistence of the methylome related to body weight (BMI) and gestational weight gain (GWG).

RESEARCH DESIGN AND METHODS

Prospective, cross-sectional study of 133 mothers with 89 BMS and 183 AMS offspring born mean 4 years after BPD and 83 unoperated control women was conducted, and differential methylation patterns in mothers were compared with those of offspring during 2-26 years.

RESULTS

Independent of maternal or offspring BMI and GWG, postoperative maternal metabolic fitness was associated with improved cardiometabolic phenotype in AMS vs. BMS offspring sustained beyond puberty. BMS offspring exhibited increasing linear trajectories of weight, cardiometabolic and inflammation risk factorsversusnormative horizontal trajectories of AMS offspring. Methylation differences between AMS and BMS offspring identified 45 625 differentially methylated sites, 73% overlapping with those of mothers vs. controls; 4 446 demonstrated similar sustained directionality of differences in methylation levels; 154 sites exhibited significant correlation coefficients (r≥0.4) overrepresented within genes associated with cardiometabolic risk, growth and inflammation.

CONCLUSION

Maternal BPD appears to epigenetically prevent transmission of cardiometabolic risk independent of BMI.
Telomere DNA G-quadruplex folding within actively extending human telomerase
Authors: Jansson Linnea I. , Parks Joseph W. , Hentschel Jendrik , Chang Terren R. , Baral Rishika , Bagshaw Clive R. , Stone Michael D.
Published: October 2018

Telomerase maintains telomere length by reverse transcribing short G-rich DNA repeat sequences from its internal RNA template. G-rich telomere DNA repeats readily fold into G-quadruplex (GQ) structures in vitro, and the presence of GQ-prone sequences throughout the genome introduces challenges to replication in vivo. Using a combination of ensemble and single-molecule telomerase assays we discovered that GQ folding of the nascent DNA product during processive addition of multiple telomere repeats modulates the kinetics of telomerase catalysis and dissociation. Telomerase reactions performed with telomere DNA primers of varying sequence or using K+ versus Li+ salts yield changes in DNA product profiles consistent with formation of GQ structure within the telomerase-DNA complex. Single-molecule FRET experiments reveal complex DNA structural dynamics during real-time catalysis, supporting the notion of nascent product folding within the active telomerase complex. To explain the observed distributions of telomere products, we fit telomerase time series data to a global kinetic model that converges to a unique set of rate constants describing each successive telomere repeat addition cycle. Our results highlight the potential influence of the intrinsic folding properties of telomere DNA during telomerase catalysis and provide a detailed characterization of GQ modulation of polymerase function.

SIGNIFICANCE

Telomeres protect the ends of linear chromosomes from illicit DNA processing events that can threaten genome stability. Telomere structure is built upon repetitive G-rich DNA repeat sequences that have the ability to fold into stable secondary structures called G-quadruplexes (GQs). In rapidly dividing cells, including the majority of human cancers, telomeres are maintained by the specialized telomerase enzyme. Thus, telomerase and its telomere DNA substrates represent important targets for developing novel cancer drugs. In this work, we provide evidence for GQ folding within the newly synthesized DNA product of an actively extending telomerase enzyme. Our results highlight the delicate interplay between the structural properties of telomere DNA and telomerase function.
A Method for Tensile Test of Geotextiles with Confining Pressure
Authors: Wang Youjiang
Published: October 2018

Geotextiles are playing an increasingly important role in civil and environment engineering applications. The performance characteristics of woven and nonwoven geotextiles and tensile test methods are reviewed. To better simulate the in-soil tensile behavior of nonwoven geotextiles, it is desirable to test their tensile properties when they are under a lateral confining pressure, and this often requires complex loading fixtures. In this study, a simple test device and a special test method are developed for testing the tensile properties of geotextiles under confining pressure. The confining device consists of two airtight aluminum chambers covered with flexible rubber membranes between which the specimen is placed, pressurized, and tested. By using specially prepared “composite” specimens, the test device can be used as an attachment to any ordinary tensile test setup. Tests are conducted on two types of nonwoven geotextiles, on an Instron tester with the confining pressure device installed. The tensile behavior of the geotextiles with and without confining pressure is evaluated and the results are reported.
Blind lattice-parameter determination of cubic and tetragonal phases with high accuracy using a single EBSD pattern
Authors: Han Ming , Chen Chen , Zhao Guangming , Li Lili , Nolze Gert , Yu Baojun , Huang Xiaodong , Zhu Ye
Published: October 2018

The Bravais lattices and their lattice parameters are blindly determined using electron backscatter diffraction (EBSD) patterns of materials with cubic or tetragonal crystal structures. Since the geometric relationships in a single EBSD pattern are overdetermined, the relative errors of determining the lattice parameters as well as the axial ratios are confined to about 0.7 ± 0.4% and 0.07 ± 0.03%, respectively, for ideal simulated EBSD patterns. The accuracy of the crystal orientation determination reaches about 0.06 ± 0.03°. With careful manual band detection, the accuracy of determining lattice parameters from experimental patterns can be as good as from simulated patterns, although the results from simulated patterns are often better than expermental patterns, which are lower quality and contain uncertain systematic errors. The reasonably high accuracy is obtained primarily because the detection of the diffracting-plane traces and zone axes is relatively accurate. The results here demonstrate that the developed procedure based on the EBSD technique presents a reliable tool for crystallographic characterization of the Bravais lattices of unknown phases.
Solving a mixture model of two-phase flow with velocity non-equilibrium using WENO wavelet methods
Authors: Kozakevicius Alice de Jesus , Zeidan Dia , Schmidt Alex A. , Jakobsson Stefan
Published: October 2018

Purpose

The purpose of this work is to present the implementation of weighted essentially non-oscillatory (WENO) wavelet methods for solving multiphase flow problems. The particular interest is gas–liquid two-phase mixture with velocity non-equilibrium. Numerical simulations are carried out on different scenarios of one-dimensional Riemann problems for gas–liquid flows. Results are validated and qualitatively compared with solutions provided by other standard numerical methods.

Design/methodology/approach

This paper extends the framework of WENO wavelet adaptive method to a fully hyperbolic two-phase flow model in a conservative form. The grid adaptivity in each time step is provided by the application of a thresholded interpolating wavelet transform. This facilitates the construction of a small yet effective sparse point representation of the solution. The method of Lax–Friedrich flux splitting is used to resolve the spatial operator in which the flux derivatives are approximated by the WENO scheme.

Findings

Hyperbolic models of two-phase flow in conservative form are efficiently solved, as shocks and rarefaction waves are precisely captured by the chosen methodology. Substantial computational gains are obtained through the grid reduction feature while maintaining the quality of the solutions. The results indicate that WENO wavelet methods are robust and sufficient to accurately simulate gas–liquid mixtures.

Originality/value

Resolution of two-phase flows is rarely studied using WENO wavelet methods. It is the first time such a study on the relative velocity is reported in two-phase flows using such methods.
Influence of factors on collapse risk of loess tunnel: a multi-index assessment model
Authors: Zhang Xueliang , Wang Meixia , Zhou Binghua , Wang Xintong
Published: October 2018

Purpose

Because of the properties of loess, the occurrence of collapse following deformation of a large settlement is a common problem during the excavation of tunnels on loess ground. Hence, risk management for safer loess tunnel construction is of great significance. The purpose of this paper is to explore the influence of factors on collapse risk of loess tunnels and establish a risk assessment model using rough set theory and extension theory.

Design/methodology/approach

The surrounding rock level, groundwater conditions, burial depth, excavation method and support close time were selected as the factors and settlement deformation was the verification index for risk assessment. First, using rough set theory, the influence of risk factors on the collapse risk of loess tunnels was calculated by researching engineering data of excavated sections. Then, a collapse risk assessment model was developed based on extension theory. As the final step, the model was applied to practical engineering in the Loess Plateau of China.

Findings

The weights of surrounding rock level, groundwater conditions, burial depth, excavation method and support close time obtained using rough set theory were respectively 10.811 per cent, 18.919 per cent, 24.324 per cent, 40.541 per cent and 5.406 per cent. The assessment results obtained using the model were in good agreement with field observations.

Originality/value

This study highlights key points in collapse risk management of loess tunnels, which could be very useful for future construction methods. The model, using easily obtained parameters, helps in predicting the collapse risk level of loess tunnels excavated under different geological conditions and by different construction organizations and provides a reference for future studies.
Factors confronting quantity surveying practice: the case of Nigeria
Authors: Ogunsina Olusola , Ekwus Obiegbu Micah , Adeniyi Onaopepo
Published: October 2018

Purpose

As the challenges confronting a system are better addressed when known and understood, this paper aims to report the findings of a study that investigated the factors confronting professional quantity surveying using Nigeria as a case.

Design/methodology/approach

A questionnaire was developed and pre-tested as the instrument for collecting data. A total of 64 quantity surveyors practicing in Lagos, Port Harcourt and Enugu completed the questionnaire out of a non-probabilistic sample of 100. Severity Index and Spearman rank correlation coefficient were used in data analysis.

Findings

The outcome revealed that the top five factors perceived to be confronting the profession include poor marketing of the profession, opposition from engineers, the dominance of multinational companies that do not have quantity surveying as a distinct profession in their country of origin, widespread corruption in Nigeria and professional incompetence of some quantity surveyors. Furthermore, the two categories of respondents – professional quantity surveyors and probationers – agree in their ranking of the factors confronting the profession. The ranking of the 17 factors between the two categories of respondents was tested using Spearman’s rho. The result showed that the difference in perception of professional members of the Nigerian Institute of Quantity Surveyors and the probationers with regard to factors confronting the quantity surveying profession is not significant at p < 0.01. These findings are then discussed in the light of previous works, and implications for both academics and professionals within the quantity surveying profession were highlighted.

Originality/value

This study has highlighted the key issues to consider as stakeholders attempt to advance the course of quantity surveying and construction cost management profession.
Coworking spaces: a new way of achieving productivity
Authors: Bueno Salvador , Rodríguez-Baltanás Gonzalo , Gallego M. Dolores
Published: October 2018

Purpose

This paper aims to explore the relationship between coworking spaces and productivity.

Design/methodology/approach

A research model was designed to carry out the analysis. Specifically, this model attempts to reveal the influence of social interactions and the coworking environment on productivity. Furthermore, three moderated variables were incorporated into the model: gender, age and level of education. A Web-based survey was conducted.

Findings

The findings confirm the positive influence of social interactions and coworking environment on productivity.

Research limitations/implications

There are two limitations. First, it is based on the perception of coworkers. It would be interesting to add the perception of coworking space managers to provide more solid findings. The second limitation is that it has not suggested any additional potential factors which could affect productivity.

Practical implications

Implications of this study are grouped into two categories. First, from an academic perspective, it contributes to the development of knowledge about the increasing use of coworking spaces. Second, from a managerial perspective, this paper highlights how environmental factors and the facilities of a workplace can help to achieve better conditions for productivity, in particular in coworking spaces.

Social implications

Furthermore, the use of social interactions in professional relationships can be understood as an alternative way to carry out new ways of doing business.

Originality/value

This paper contributes to the enrichment of knowledge-concerning coworking spaces developed a pioneering study.
Organizational archives and historical narratives
Authors: Barros Amon , Carneiro Adéle de Toledo , Wanderley Sergio
Published: October 2018

Purpose

The purpose of this paper is to present the role of reflexivity in relation to archives and narratives.

Design/methodology/approach

The authors problematize the concept of “archive,” by engaging with debates in philosophy and the archival theory. The authors also revisit historical theories and debates on the role of the narrative within historiography. Finally, the authors consider reflexivity as a methodological attitude taken by the researcher at all stages of the investigation from challenging theoretical assumptions of empirical materials to questioning the very narrative that is created when looking for alternative ones.

Findings

This paper poses questions about documents and archives that emerge from reflexivity. The authors claim that reflexivity is an ethos that allows researchers to keep the multiple narratives in which they are entangled in check. The paper brings a framework that allows researchers to use reflexivity to become more conscious of the complexities and ambiguities within the research process that leads to the writing of historical narratives.

Research limitations/implications

This paper points to the need to enhance the reflexivity at every stage of the research, including “interrogating” the archives and documents, which are compiled under a narrative.

Practical implications

The authors highlighted the multiple characteristics of archives, their meanings and the possibilities of writing narratives about them through reflexivity. The authors have the historical narrative as one possible reconstruction of a historical object, which is connected to the production conditions of the text. Through reflexivity, the authors discussed the socially constructed nature of the documents and the archives. Finally, the authors believe that debates around the production of this knowledge should continue, focusing especially on building bridges with the field of history.

Social implications

Historical narratives do not depend on the scientific character of historical sources, but it considers reflexivity by the researcher regarding the search, collection, reading and analysis of historical documents. In addition, it is necessary to think about the use of documents and archives and histories in a reflective way for a writing of history and, indirectly, for a contextual understanding of the time observed and as forged sources – or discarded – and made available.

Originality/value

Challenging the use of documents and archives in a reflexive way for the writing of historical narratives and for contextual understanding of the past is key to a richer relationship between management and history. This paper points to the role of reflexivity in relation to archives and narratives in the practice of (re)constructing the organizational past from memories and silences. It also highlights how reflexivity can be incorporated in the research process to enrich the writing of the historical narrative.
Design optimisation for cold-formed steel residential roof truss using genetic algorithm
Authors: Kok Ka Yee , Lau Hieng Ho , Phan Thanh Duoc , Ting TIina Chui Huon
Published: October 2018

Purpose

This paper aims to present the design optimisation using genetic algorithm (GA) to achieve the highest strength to weight (S/W) ratio, for cold-formed steel residential roof truss.

Design/methodology/approach

The GA developed in this research simultaneously optimises roof pitch, truss configurations, joint coordinates and applied loading of typical dual-pitched symmetrical residential roof truss. The residential roof truss was considered with incremental uniform distributed loading, in both gravitational and uplift directions. The structural analyses of trusses were executed in this GA using finite element toolbox. The ultimate strength and serviceability of trusses were checked through the design formulation implemented in GA, according to the Australian standard, AS/NZS 4600 Cold-formed Steel Structures.

Findings

An optimum double-Fink roof truss which possess highest S/W ratio using GA was determined, with optimum roof pitch of 15Â°. The optimised roof truss is suitable for industrial application with its higher S/W ratio and cost-effectiveness. The combined methodology of multi-level optimisation and simultaneous optimisation developed in this research could determine optimum roof truss with consistent S/W ratio, although with huge GA search space.

Research limitations/implications

The sizing of roof truss member is not optimised in this paper. Only single type of cold-formed steel section is used throughout the whole optimisation. The design of truss connection is not considered in this paper. The corresponding connection costs are not included in the proposed optimisation.

Practical implications

The optimum roof truss presented in this paper is suitable for industrial application with higher S/W ratio and lower cost, in either gravitational or uplift loading configurations.

Originality/value

This research demonstrates the approaches in combining multi-level optimisation and simultaneous optimisation to handle large number of variables and hence executed an efficient design optimisation. The GA designed in this research determines the optimum residential roof truss with highest S/W ratio, instead of lightest truss weight in previous studies.
The Role of Gender in Entrepreneur–Investor Relationships: A Signaling Theory Approach
Authors: Alsos Gry Agnete , Ljunggren Elisabet
Published: October 2018

This study adopts a gender perspective to analyze funding decisions made by an investment fund that invests equity stakes in new ventures. Prior research has indicated that there is gender skewness in risk capital investments resulting from a combination of demand‐ and supply‐side issues. We apply signaling theory to examine the interface between demand and supply to understand gender biases related to risk capital investments. In‐depth analyses of decision documents from four investment cases show that gender plays a role in the signals that are communicated in the prefunding entrepreneur–investor relationship.
Streamlining the Power Generation Profile of Concentrating Solar Power Plants
Authors: Abutayeh Mohammad , Alazzam Anas , El-Khasawneh Bashar
Published: October 2018

A scheme to streamline the electric power generation profile of concentrating solar power plants of the parabolic trough collector type is suggested. The scheme seeks to even out heat transfer rates from the solar field to the power block by splitting the typical heat transfer fluid loop into two loops using an extra vessel and an extra pump. In the first loop, cold heat transfer fluid is pumped by the cold pump from the cold vessel to the solar field to collect heat before accumulating in the newly introduced hot vessel. In the second loop, hot heat transfer fluid is pumped by the hot pump from the hot vessel to a heat exchanger train to supply the power block with its heat load before accumulating in the cold vessel. The new scheme moderately decouples heat supply from heat sink allowing for more control of heat delivery rates thereby evening out power generation.
Performance Prediction and Optimization of an Organic Rankine Cycle (ORC) Using Back Propagation Neural Network for Diesel Engine Waste Heat Recovery
Authors: Yang Fubin , Cho Heejin , Zhang Hongguang
Published: October 2018

This paper presents a methodology to predict and optimize performance of an organic Rankine cycle (ORC) using a back propagation neural network (BPNN) for diesel engine waste heat recovery. A test bench of an ORC with a diesel engine is established to collect experimental data. The collected data is used to train and test a BPNN model for performance prediction and optimization. After evaluating different hidden layers, a BPNN model of the ORC system is determined with consideration of mean squared error and correlation coefficient. The effects of key operating parameters on the power output of the ORC system and exhaust temperature at the outlet of the evaporator are evaluated using the proposed model and further discussed. Finally, a multi-objective optimization of the ORC system are conducted for maximizing power output and minimizing exhaust temperature at the outlet of the evaporator based on the proposed BPNN model. The results show that the proposed BPNN model has a high prediction accuracy and the maximum relative error of the power output is less than 5%. It also shows that when the operations are optimized based on the proposed model, the power output of the ORC system can be higher than the experimental results.
100% Test Burn of Torrefied Wood Pellets at a Full-Scale Pulverized Coal Fired Utility Steam Generator
Authors: Hatt Rod , Rodgers David A. T. , Curtis Randy
Published: October 2018

Portland General Electric’s (PGE) Boardman plant is a nominal 600 megawatt (MW) coal fired unit that burns sub-bituminous Powder River Basin (PRB) coal from Wyoming. This paper will cover the experience and results of PGE’s Boardman plant operating on 100% torrefied wood (TW) pellets at 255 MW consuming almost 5000 tons of pellets. Results were positive and include suitable handing after inclement weathering for months. Pulverizers were able to handle the TW pellets with adjustments, resulting in near 100% combustion efficiency. Particulates were controlled with an electrostatic precipitator (ESP). Topics investigated include torrefied wood production, fuel handling and storage on the front end of the test. Fuel handling, pulverization, combustion, emissions, and ESP performance were monitored during the test and are reported here. Several one mill tests were conducted prior to the 100% test to evaluate and improve mill performance. This test showed that a pulverized coal (PC) boiler can operate on 100% TW fuel with minimal operational changes.
Utilization of Hydro-Turbines in Wastewater Treatment Plants (WWTPs)
Authors: Abbas Ahmad I. , Qandil Mohammad D. , Al-Haddad Muhannad R. , Saravani Mandana S. , Amano Ryoichi S.
Published: October 2018

Wastewater treatment plants (WWTPs) are a significant energy consumer, yet there are several opportunities of implementing on-site power generation systems. Within the treatment process, the high flow rate of effluent is produced and discharged to a nearby water body by gravity. Thus, hydro turbines can be utilized to generate power in such application due to a difference in elevation and high flow rate. This paper presents a case study of introducing a hydro turbine in wastewater treatment plant in Wisconsin and evaluating the power output in addition to determining the energy savings. The wastewater treatment plant considered in this study has an effluent flow rate of 190 MGD (million gallons per day) and elevation difference of 3 meters (10 feet) between the final stage of treatment and the discharge point. Based on the aforementioned parameters; hubless rim-drive Kaplan type hydro turbine (RDT) is the optimal choice to be used in such application. The RDT is designed and optimized by using in-house code. A computational fluid dynamics (CFD) software is applied to evaluate the performance of the proposed model, and the system is simulated through HOMER software to validate the results generated by the CFD. The expected savings is estimated to be 1,564 MWh/year.
Accurate and Data-Limited Prediction for Smart Home Energy Management
Authors: Aksanli Baris
Published: October 2018

Residential energy applications have become an important domain of cyber-physical systems. These applications provide significant opportunities for end-users to reduce their electricity costs and for the utilities to balance their supply and demand in the most effective way. One of the most important applications is predicting the total energy usage of a house. However, an accurate time-series prediction may require significant amount of data, e.g. per appliance energy consumption values, that need costly installations, data storage units, and computation and communication devices. In this paper, we propose a framework that uses a forward-selection-based input filtering mechanism for residential prediction applications. Our framework can effectively reduce the amount of data required for residential energy prediction without sacrificing prediction performance. We demonstrate that 94% of the houses can leverage our method, which leads to up to 80% reduction in required data, greatly reducing the system cost and overhead.
Effective Thermal Conductivity of Wall-Adjacent Layer in Gravity-Driven Vertical Dense Granular Flows
Authors: Watkins Megan F. , Chilamkurti Yesaswi N. , Gould Richard D.
Published: October 2018

Particle-based heat transfer fluids for concentrated solar power (CSP) tower applications offer a unique advantage over traditional fluids as they have the potential to reach very high operating temperatures. Our work studies the heat transfer behavior of dense granular flows through cylindrical tubes as a potential system configuration for CSP towers. Thus far, we have experimentally investigated the heat transfer to such flows. Our results corroborate the observations of other researchers; namely, that the discrete nature of the flow limits the heat transferred from the tube wall to the flow due to an increased thermal resistance in the wall-adjacent layer. The present study focuses on this near-wall phenomenon, examining how it varies with system configuration and flow rate. A correlation to predict the thermal resistance, in the form of an effective thermal conductivity, was developed based on the underlying physics controlling the heat transfer. The model developed focuses on heat transfer via conduction, considering the heat transfer to particles in contact with the wall, heat transfer to particles not in contact with the wall, and heat transfer through the void spaces. Discrete Element Method simulations were used to examine the flow parameters necessary to understand the heat transfer in the wall-adjacent layer, in particular the packing fraction in the wall-adjacent layer and the number of particle-wall contacts. Incorporation of the model into the single-resistance model developed by Sullivan & Sabersky [1] showed good agreement with their experimental results and those of Natarajan & Hunt [2].
Melting Process Expedition of Phase Change Materials via Silicone Oil
Authors: Sobhansarbandi Sarvenaz , Hassanipour Fatemeh
Published: October 2018

This paper presents a novel method of heat transfer enhancement and melting process expedition of phase change materials (PCMs) via silicone oil for the application in thermal energy storage systems. Sudden spot heating/cooling of the PCM causes a non-uniform melting process and in some cases the volume expansion/contraction. To avoid this malfunction, silicone oil can be applied in these systems to increase convective heat transfer (stirring effect). The feasibility of this method is investigated by two experimental analysis, one by having the mixture in a cylindrical container and one in a cubic container. The results from the images taken by Charge-Coupled Device (CCD) camera in the first analysis show a uniform melting process of the PCM. In the second analysis, the comparison is made for the two parallel setups with and without the silicone oil with the same operating conditions. The results show that in the system that lacks silicone oil, the paraffin starts melting after around 11 minutes from the heater start-up, while this time is around 6 minutes in the system with silicone oil. The effectiveness of silicone oil in enhancing the heat transfer rate is shown by a temperature rise of around 10 °C in the container. Applying PCMs in conjunction with silicone oil in various thermal storage systems for heating/cooling applications specifically in solar thermal collectors, enables heat transfer enhancement and consequently heat storage directly on the system.
Evaluation of Alternative Designs for a High Temperature Particle-to-SCO2 Heat Exchanger
Authors: Ho Clifford K. , Carlson Matthew , Albrecht Kevin J. , Ma Zhiwen , Jeter Sheldon , Nguyen Clayton M.
Published: October 2018

This paper presents an evaluation of alternative particle heat-exchanger designs, including moving packed-bed and fluidized-bed designs, for high-temperature heating of a solar-driven supercritical CO2 (sCO2) Brayton power cycle. The design requirements for high pressure (≥ 20 MPa) and high temperature (≥ 700 °C) operation associated with sCO2 posed several challenges requiring high-strength materials for piping and/or diffusion bonding for plates. Designs from several vendors for a 100 kW-thermal particle-to-sCO2 heat exchanger were evaluated as part of this project. Cost, heat-transfer coefficient, structural reliability, manufacturability, parasitics and heat losses, scalability, compatibility, erosion and corrosion, transient operation, and inspection ease were considered in the evaluation. An analytical hierarchy process was used to weight and compare the criteria for the different design options. The fluidized-bed design fared the best on heat transfer coefficient, structural reliability, scalability and inspection ease, while the moving packed-bed designs fared the best on cost, parasitics and heat losses, manufacturability, compatibility, erosion and corrosion, and transient operation. A 100 kWt shell-and-plate design was ultimately selected for construction and integration with Sandia’s falling particle receiver system.