bluuebunny/crossref_metadata_2025 huggingface dataset:
Disrupted cholinergic modulation can underlie abnormal gamma rhythms in schizophrenia and auditory hallucination
Authors: Lee Jung Hoon
Published: September 2016

The pathophysiology of auditory hallucination, a common symptom of schizophrenia, has yet been understood, but during auditory hallucination, primary auditory cortex (A1) shows paradoxical responses. When auditory stimuli are absent, A1 becomes hyperactive, while A1 responses to auditory stimuli are reduced. Such activation pattern of A1 responses during auditory hallucination is consistent with aberrant gamma rhythms in schizophrenia observed during auditory tasks, raising the possibility that the pathology underlying abnormal gamma rhythms can account for auditory hallucination. Moreover, A1 receives top-down signals in the gamma frequency band from an adjacent association area (Par2), and cholinergic modulation regulates interactions between A1 and Par2. In this study, we utilized a computational model of A1 to ask if disrupted cholinergic modulation could underlie abnormal gamma rhythms in schizophrenia. Furthermore, based on our simulation results, we propose potential pathology by which A1 can directly contribute to auditory hallucination.
Evolutionary Genetics of Insecticide Resistance and the Effects of Chemical Rotation
Authors: Siniard Dylan J. , Wade Michael J. , Drury Douglas W.
Published: September 2016

Repeated use of the same class of pesticides to control a target pest is a form of artificial selection that leads to pesticide resistance. We studied insecticide resistance and cross-resistance to five commercial insecticides in each of six populations of the red flour beetle,Tribolium castaneum. We estimated the dosage response curves for lethality in each parent population for each insecticide and found an 800-fold difference among populations in resistance to insecticides. As expected, a naïve laboratory population was among the most sensitive of populations to most insecticides. We then used inbred lines derived from five of these populations to estimate the heritability (h2) of resistance for each pesticide and the genetic correlation (rG) of resistance among pesticides in each population. These quantitative genetic parameters allow insight into the adaptive potential of populations to further evolve insecticide resistance. Lastly, we use our estimates of the genetic variance and covariance of resistance and stochastic simulations to evaluate the efficacy of “windowing” as an insecticide resistance management strategy, where the application of several insecticides is rotated on a periodic basis.
Unraveling the differential dynamics of developmental fate in central and peripheral nervous systems
Authors: Sengupta Dola , Kar Sandip
Published: September 2016

Bone morphogenetic protein 2 (BMP2), differentially regulates the developmental lineage commitment of neural stem cells (NSC’s) in central and peripheral nervous systems. However, the precise mechanism beneath such observations still remains illusive. To decipher the intricacies of this mechanism, we propose a generic mathematical model of BMP2 driven differentiation regulation of NSC’s. The model efficiently captures the dynamics of the wild-type as well as various mutant and over-expression phenotypes for NSC’s in central nervous system. Our model predicts that the differential developmental dynamics of the NSC’s in peripheral nervous system can be reconciled by altering the relative positions of the two mutually interconnected bi-unstable switches inherently present in the steady state dynamics of the crucial developmental fate regulatory proteins as a function of BMP2 dose. This model thus provides a novel mechanistic insight and has the potential to deliver exciting therapeutic strategies for neuronal regeneration from NSC’s of different origin.
Pleiotropy-robust Mendelian Randomization
Authors: van Kippersluis Hans , Rietveld Cornelius A
Published: September 2016

Background

The potential of Mendelian Randomization studies is rapidly expanding due to (i) the growing power of GWAS meta-analyses to detect genetic variants associated with several exposures, and (ii) the increasing availability of these genetic variants in large-scale surveys. However, without a proper biological understanding of the pleiotropic working of genetic variants, a fundamental assumption of Mendelian Randomization (the exclusion restriction) can always be contested.

Methods

We build upon and synthesize recent advances in the econometric literature on instrumental variables (IV) estimation that test and relax the exclusion restriction. Our Pleiotropy-robust Mendelian Randomization (PRMR) method first estimates the degree of pleiotropy, and in turn corrects for it. If a sample exists for which the genetic variants do not affect the exposure, and pleiotropic effects are homogenous, PRMR obtains unbiased estimates of causal effects in case of pleiotropy.

Results

Simulations show that existing MR methods produce biased estimators for realistic forms of pleiotropy. Under the aforementioned assumptions, PRMR produces unbiased estimators. We illustrate the practical use of PRMR by estimating the causal effect of (i) cigarettes smoked per day on Body Mass Index (BMI); (ii) prostate cancer on self-reported health, and (iii) educational attainment on BMI in the UK Biobank data.

Conclusions

PRMR allows for instrumental variables that violate the exclusion restriction due to pleiotropy, and corrects for pleiotropy in the estimation of the causal effect. If the degree of pleiotropy is unknown, PRMR can still be used as a sensitivity analysis.

Key messages

If genetic variants have pleiotropic effects, causal estimates of Mendelian Randomization studies will be biased.

Pleiotropy-robust Mendelian Randomization (PRMR) produces unbiased causal estimates in case (i) a subsample can be identified for which the genetic variants do not affect the exposure, and (ii) pleiotropic effects are homogenous.

If such a subsample does not exist, PRMR can still routinely be reported as a sensitivity analysis in any MR analysis.

If pleiotropic effects are not homogenous, PRMR can be used as an informal test to gauge the exclusion restriction.
Regions of very low H3K27me3 partition theDrosophilagenome into topological domains
Authors: El-Sharnouby Sherif , Fischer Bettina , Magbanua Jose Paolo , Umans Benjamin , Flower Rosalyn , Choo Siew Woh , Russell Steven , White Robert
Published: September 2016

Background

It is now well established that eukaryote genomes have a common architectural organization into topologically associated domains (TADs) and evidence is accumulating that this organization plays an important role in gene regulation. However, the mechanisms that partition the genome into TADs and the nature of domain boundaries are still poorly understood.

Results

We have investigated boundary regions in the Drosophila genome and find that they can be identified as domains of very low H3K27me3. The genome-wide H3K27me3 profile partitions into two states; very low H3K27me3 identifies Depleted (D) domains that contain housekeeping genes and their regulators such as the histone acetyltransferase-containing NSL complex, whereas domains containing mid-to-high levels of H3K27me3 (Enriched or E domains) are associated with regulated genes, irrespective of whether they are active or inactive. The D domains correlate with the boundaries of TADs and are enriched in a subset of architectural proteins, particularly Chromator, BEAF-32, and Z4/Putzig. However, rather than being clustered at the borders of these domains, these proteins bind throughout the H3K27me3-depleted regions and are much more strongly associated with the transcription start sites of housekeeping genes than with the H3K27me3 domain boundaries.

Conclusions

We suggest that the D domain chromatin state, characterised by very low H3K27me3 and established by housekeeping gene regulators, acts to separate topological domains thereby setting up the domain architecture of the genome.
Selection on heterozygosity drives adaptation in intra- and interspecific hybrids
Authors: Smukowski Heil Caiti S. , DeSevo Christopher G. , Pai Dave A. , Tucker Cheryl M. , Hoang Margaret L. , Dunham Maitreya J.
Published: September 2016

Hybridization is often considered maladaptive, but sometimes hybrids can invade new ecological niches and adapt to novel or stressful environments better than their parents. However, the genomic changes that occur following hybridization and facilitate genome resolution and/or adaptation are not well understood. Here, we address these questions using experimental evolution of de novo interspecific hybrid yeastSaccharomyces cerevisiaexSaccharomyces uvarumand their parentals. We evolved these strains in nutrient limited conditions for hundreds of generations and sequenced the resulting cultures to identify genomic changes. Analysis of 16 hybrid clones and 16 parental clones identified numerous point mutations, copy number changes, and loss of heterozygosity events, including a number of nuclear-mitochondrial mutations and species biased amplification of nutrient transporters. We focused on a particularly interesting example, in which we saw repeated loss of heterozygosity at the high affinity phosphate transporter genePHO84in both intra- and interspecific hybrids. Using allele replacement methods, we tested the fitness of different alleles in hybrid andS. cerevisiaestrain backgrounds and found that the loss of heterozygosity is indeed the result of selection on one allele over the other in bothS. cerevisiaeand the hybrids. This illuminates an example where hybrid genome resolution is driven by positive selection on existing heterozygosity, and generally demonstrates that outcrossing need not be frequent to have long lasting impacts on adaptation.
Natural Variation in ArabidopsisCvi-0 Accession Uncovers Regulation of Guard Cell CO2Signaling by MPK12
Authors: Jakobson Liina , Vaahtera Lauri , Tõldsepp Kadri , Nuhkat Maris , Wang Cun , Wang Yuh-Shuh , Hõrak Hanna , Valk Ervin , Pechter Priit , Sindarovska Yana , Tang Jing , Xiao Chuanlei , Xu Yang , Gerst Talas Ulvi , Remm Maido , Kangasjärvi Saijaliisa , Roelfsema M. Rob G. , Hu Honghong , Kangasjärvi Jaakko , Loog Mart , Schroeder Julian I. , Kollist Hannes , Brosché Mikael
Published: September 2016

Plant gas exchange is regulated by guard cells that form stomatal pores. Stomatal adjustments are crucial for plant survival; they regulate uptake of CO2for photosynthesis, loss of water and entrance of air pollutants such as ozone. We mapped ozone hypersensitivity, more open stomata and stomatal CO2-insensitivity phenotypes of theArabidopsis thalianaaccession Cvi-0 to a single amino acid substitution in MAP kinase 12 (MPK12). In parallel we showed that stomatal CO2-insensitivity phenotypes of a mutantcis(CO2-insensitive) were caused by a deletion ofMPK12. Lack of MPK12 impaired bicarbonate-induced activation of S-type anion channels. We demonstrated that MPK12 interacted with the protein kinase HT1, a central node in guard cell CO2signaling, and that MPK12 can function as an inhibitor of HT1. These data provide a new function for plant MPKs as protein kinase inhibitors and suggest a mechanism through which guard cell CO2signaling controls plant water management.
Activity of theC. elegansegg-laying behavior circuit is controlled by competing activation and feedback inhibition
Authors: Collins Kevin M. , Bode Addys , Fernandez Robert W. , Tanis Jessica E. , Brewer Jacob , Creamer Matthew S. , Koelle Michael R.
Published: September 2016

Like many behaviors,Caenorhabditis elegansegg laying alternates between inactive and active states. To understand how the underlying neural circuit turns the behavior on and off, we optically recorded circuit activity in behaving animals while manipulating circuit function using mutations, optogenetics, and drugs. In the active state, the circuit shows rhythmic activity phased with the body bends of locomotion. The serotonergic HSN command neurons initiate the active state, but accumulation of unlaid eggs also promotes the active state independent of the HSNs. The cholinergic VC motor neurons slow locomotion during egg-laying muscle contraction and egg release. The uv1 neuroendocrine cells mechanically sense passage of eggs through the vulva and release tyramine to inhibit egg laying, in part via the LGC-55 tyramine-gated Cl−channel on the HSNs. Our results identify discrete signals that entrain or detach the circuit from the locomotion central pattern generator to produce active and inactive states.
Precommitment low-level Neurog3 expression defines a long-lived mitotic endocrine-biased progenitor pool that drives production of endocrine-committed cells
Authors: Bechard Matthew E. , Bankaitis Eric D. , Hipkens Susan B. , Ustione Alessandro , Piston David W. , Yang Yu-Ping , Magnuson Mark A. , Wright Christopher V.E.
Published: September 2016

The current model for endocrine cell specification in the pancreas invokes high-level production of the transcription factor Neurogenin 3 (Neurog3) in Sox9+ bipotent epithelial cells as the trigger for endocrine commitment, cell cycle exit, and rapid delamination toward proto-islet clusters. This model posits a transient Neurog3 expression state and short epithelial residence period. We show, however, that a Neurog3TA.LO cell population, defined as Neurog3 transcriptionally active and Sox9+ and often containing nonimmunodetectable Neurog3 protein, has a relatively high mitotic index and prolonged epithelial residency. We propose that this endocrine-biased mitotic progenitor state is functionally separated from a pro-ductal pool and endows them with long-term capacity to make endocrine fate-directed progeny. A novel BAC transgenic Neurog3 reporter detected two types of mitotic behavior in Sox9+Neurog3TA.LO progenitors, associated with progenitor pool maintenance or derivation of endocrine-committed Neurog3HI cells, respectively. Moreover, limiting Neurog3 expression dramatically increased the proportional representation of Sox9+Neurog3TA.LO progenitors, with a doubling of its mitotic index relative to normal Neurog3 expression, suggesting that low Neurog3 expression is a defining feature of this cycling endocrine-biased state. We propose that Sox9+Neurog3TA.LO endocrine-biased progenitors feed production of Neurog3HI endocrine-committed cells during pancreas organogenesis.
IKKβ promotes metabolic adaptation to glutamine deprivation via phosphorylation and inhibition of PFKFB3
Authors: Reid Michael A. , Lowman Xazmin H. , Pan Min , Tran Thai Q. , Warmoes Marc O. , Ishak Gabra Mari B. , Yang Ying , Locasale Jason W. , Kong Mei
Published: September 2016

Glutamine is an essential nutrient for cancer cell survival and proliferation. Enhanced utilization of glutamine often depletes its local supply, yet how cancer cells adapt to low glutamine conditions is largely unknown. Here, we report that IκB kinase β (IKKβ) is activated upon glutamine deprivation and is required for cell survival independently of NF-κB transcription. We demonstrate that IKKβ directly interacts with and phosphorylates 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase isoform 3 (PFKFB3), a major driver of aerobic glycolysis, at Ser269 upon glutamine deprivation to inhibit its activity, thereby down-regulating aerobic glycolysis when glutamine levels are low. Thus, due to lack of inhibition of PFKFB3, IKKβ-deficient cells exhibit elevated aerobic glycolysis and lactate production, leading to less glucose carbons contributing to tricarboxylic acid (TCA) cycle intermediates and the pentose phosphate pathway, which results in increased glutamine dependence for both TCA cycle intermediates and reactive oxygen species suppression. Therefore, coinhibition of IKKβ and glutamine metabolism results in dramatic synergistic killing of cancer cells both in vitro and in vivo. In all, our results uncover a previously unidentified role of IKKβ in regulating glycolysis, sensing low-glutamine-induced metabolic stress, and promoting cellular adaptation to nutrient availability.
Making projects critical 15 years on: a retrospective reflection (2001-2016)
Authors: Hodgson Damian , Cicmil Svetlana
Published: September 2016

Purpose

The purpose of this paper is to review the formation and evolution of the “Making Projects Critical” movement in project management research.

Design/methodology/approach

Retrospective and discursive paper.

Findings

Reflections on tensions and challenges faced by the MPC movement.

Originality/value

The paper establishes the historical trajectory of this movement and clarifies the tensions and challenges faced by MPC.
Fast damaging processes in the TaN thin film absorbers under action of nanosecond electrical pulses
Authors: Ardaravičius Linas , Keršulis Skirmantas , Kiprijanovič Oleg , Šimkevicius Česlovas , Vengalis Bonifacas
Published: September 2016

Purpose

The purpose of this paper is to investigate damaging processes in TaN thin film absorbers under action of high-voltage electrical pulse of nanosecond duration. Despite having mechanical origin of crack opening, estimation based on the readings from oscillograms shows uncharacteristically high velocities of the crack propagation.

Design/methodology/approach

Microscopic images of damaged absorbers showing the final result of the damaging process provided initial information about its geometrical peculiarities. Then, to clarify the dynamics of the process, the authors create the model of the crack, having elements of self-similarities and multiple stage opening. The influence of heating induced by current concentration at crack tip and of magnetic stress of this concentrated current are both included in the model.

Findings

Using physical parameters of TaN layers with flowing current and performing calculations the authors define the conditions required to initiate the damaging process and to sustain it. Danger of such damage is relevant for high-Tc superconducting thin films after their switching to normal state which is induced by the high-voltage pulse.

Practical implications

There were made recommendations to manufactures aiming to improve electrical durability of the absorbers in an effort to prevent the damaging influence of power nanosecond electrical pulses.

Originality/value

Three stage opening model implies the appearance of zone of high-energy dissipation that can lead to detonation-like destruction of the film and, therefore, explain the high velocities of crack propagation.
Influence of country image on country brand equity: application to higher education services
Authors: Herrero-Crespo Ángel , San Martín Gutiérrez Héctor , Garcia-Salmones Maria del Mar
Published: September 2016

Purpose

The purpose of this paper is to analyze how country image affects the dimensions of country brand equity (CBE) (i.e. awareness, image, perceived quality and loyalty) in the higher education sector, as well as the interrelationships between these dimensions.

Design/methodology/approach

Quantitative research with 208 international students who were starting the academic year at a Spanish university was performed to test the hypotheses. In accordance with the characteristics of the target population, the subjects interviewed were mainly from Europe and the Americas.

Findings

The results indicate that the country image affects the perceived quality and awareness of the universities in the country. Additionally, a hierarchy of effects between the dimensions of CBE was found. In particular, loyalty toward the universities of a country is positively influenced by their perceived quality, which is affected by image and awareness of these universities. For its part, the image of universities is positively influenced by the awareness attributed to them by international students.

Practical implications

These results have implications for marketing activities aimed at the internationalization of higher education institutions and, therefore, their appeal to international students.

Originality/value

The paper’s findings represent an important step in the advancement of knowledge about CBE by taking as a basis a complex model that involves the different dimensions of this construct together with a relevant variable in international marketing, that is, country image.
Here, there and everywhere: a study of consumer centrism
Authors: Prince Melvin , Davies Mark A.P. , Cleveland Mark , Palihawadana Dayananda
Published: September 2016

Purpose

A first objective is to add insight into how constructs of ethnocentrism, xenocentrism and cosmopolitanism relate to each other. Knowledge of how these constructs overlap or work together in affecting consumer preferences will offer global marketers insights for designing appropriate marketing strategies. The second objective is to extend this knowledge by examining the correspondence of these three constructs to a nomological network of dispositional concepts pertinent for product positioning and market segmentation. The third objective is to empirically examine the extent to which the measures, construct structure and associative relationships are robust in different national research settings. The paper aims to discuss these issues.

Design/methodology/approach

Surveying British and American consumers, this study examines and analyzes the correspondence of these identity-relevant constructs within a nomological net of pertinent concepts: consciousness-of-kind, global consumption orientation, materialism and natural environment concern.

Findings

The hypothesized negative links between CET-XEN and CET-COS, and the predicted positive connection between XEN-COS were all confirmed on the latent factor results for the combined data set. The negative correlation between CET-XEN was of a considerably lower magnitude than that for CET-COS.

Originality/value

To date, no research has used an identity theory framework and simultaneously examined in a cross-cultural context the interrelationships of consumer ethnocentrism consumer xenocentrism and cosmopolitanism – and their differentiating linkages to a multiplicity of consumer dispositions.
Maltese certified public accountants and whistle-blowing: traits, influences and propensity
Authors: Francalanza Charles , Buttigieg Emanuela
Published: September 2016

Purpose

The purpose of this paper is to deal with an important element of the whistle-blowing decision, the whistle-blower. It is set within the environment of the small Mediterranean island of Malta. It has two objectives. The first is to identify the more important personality traits of the potential Maltese accountant whistle-blower and the situational factors that mostly affect his/her whistle-blowing decision. The second objective is to develop a regression model that can be used to identify the potential Maltese accountant whistle-blower.

Design/methodology/approach

The study is in the form of two e-mail questionnaires sent to Maltese accounting practitioners.

Findings

The personality traits of conscientiousness, openness to experience and extraversion and the situational factors of ethical considerations and professional requirements were found to be the more significant. The regression model proved substantially correct in singling out the potential Maltese accountant whistle-blower.

Research limitations/implications

The results are based on the replies of respondents to two questionnaires and not actual whistle-blowing behaviour. Also, the propensity to be a whistle-blower or not may not be a constant since it can be affected by shifts in internal attributes and situational factors.

Practical implications

Besides academic qualifications, the personality of the individual and his/her potential reaction to the working environment should be given due consideration in the recruitment of accounting staff.

Originality/value

The research contributes to the literature on the accountant whistle-blower in a small country setting that is rarely the subject of study.
Corporate share repurchases in the UK
Authors: Dhanani Alpa
Published: September 2016

Purpose

The purpose of this paper is to examine motivations underlying UK repurchase activity. Specifically, the paper inquires into the relevance of a range of different explanations for repurchases and perceptions of regulation surrounding them. Emphasis of the paper is, however, on motives linked specifically to repurchases rather than income distribution, more generally.

Design/methodology/approach

The study uses a survey approach to capture the views on repurchases of corporate managers and investors. It supplements the survey data with secondary information about the companies to better understand repurchase behaviour.

Findings

Results indicate that repurchase use is influenced by motives linked specifically to this tool rather than those associated with income distribution, more generally. In particular, repurchases are used to return surplus cash to investors, signal undervaluation and influence gearing and earnings per share levels. In the latter case, companies appear to use repurchases to perform a value added role, alongside manipulating the EPS level and thus the latter may simply be a by-product of the former. Private investors may nevertheless be vulnerable to such manipulation, given their limited financial literacy.

Research limitations/implications

The study relied on a survey of managers and investors and univariate analysis. In the former case, respondent numbers, particularly for the investor community were low, raising questions as to the generalisability of the data. In the latter, the results may be mis-stated owing to the simplicity of the analysis.

Practical implications

Overall, the survey results suggest that firms use repurchase programmes in different contexts to dividend payments and in appropriate circumstances. While managers and investors broadly share similar views, private shareholders may be in a vulnerable position given their limited financial literacy.

Originality/value

This is the first UK study on repurchases that examines the relative importance of a range of motives underlying repurchases. Moreover, it assesses in detail the core hypotheses that are linked specifically to repurchase programmes to better understand UK repurchase behaviour. It does so by supplementing the survey data with additional company information and comparing the views of the different audiences surveyed.
Tax reforms and revenue mobilization in Ghana
Authors: Bekoe William , Danquah Michael , Senahey Sampson Kwabena
Published: September 2016

Purpose

The purpose of this paper is to comprehensively examine Ghana’s tax reform programme and investigate whether it has facilitated the revenue mobilization capacity of the overall tax system and of individual taxes on the basis of estimates of tax buoyancies and elasticities.

Design/methodology/approach

This study uses the proportional adjustment approach to estimate tax buoyancies and elasticities of the overall tax system and of individual taxes for the pre and post tax reform period over the 1970-2013 period.

Findings

The results show that in general, tax reforms had a positive influence on the overall tax structure and on the individual tax handles as evidenced in the more than unity buoyancy and elasticity. All the individual taxes, except excise duties, recorded buoyancies and elasticities of more than unity during the reform period.

Practical implications

Tax authorities ought to move away from income-based taxation which discriminates against saving and investment, in favour of consumption-based taxes in conformity with international standards. Emphasis must also be placed on those taxes that have high revenue elasticities. These taxes include the personal, corporate, the Value Added Tax, and the import duties.

Originality/value

In this study, the paper extends and disaggregates the data on taxes, account for discretionary tax changes from the historical time series data, and use the adjusted historical time series data to estimate tax elasticity. The study therefore provides an in-depth understanding of the effects of the tax reforms on the overall tax system and of individual taxes in Ghana.
Monetary decentralization in the United States: is there a case for multiple currencies?
Authors: Chupp Benjamin Andrew
Published: September 2016

Purpose

When sectoral shocks hit a large, regionally heterogeneous economy, it is likely that regions with sectoral specialization will be affected in different ways. In these cases, it might be optimal for the country to decentralize the currency into a number of regional currencies, thus allowing for differentiated monetary policy. The paper aims to discuss these issues.

Design/methodology/approach

The author explicates the potential benefits and costs to decentralization. The author also highlights characteristics that should be satisfied in order to consider multiple currencies. This paper uses a theoretical and empirical model to test if the USA contains regional optimal currency areas. The author tests five potential divisions of the states into monetary subunions.

Findings

One of these divisions is proven to result in higher welfare (a 2 percent increase) than the status quo national monetary union. Thus, the USA is not an optimal currency area, and monetary decentralization could be a feasible and welfare-improving option for future policy.

Originality/value

There have been no previous studies of monetary divisions. Given the importance of fiscal decentralization, it is important to also understand the implications of monetary decentralization.
What econo-physics can tell us about Korean equity market co-movements?
Authors: Shah Aasif , Deo Malabika , King Wayne
Published: September 2016

Purpose

The purpose of this paper is to derive crucial insights from multi-scale analysis to detect equity return co-movements between Korean and emerging Asian markets.

Design/methodology/approach

Wavelet correlation, wavelet coherence and wavelet clustering measures are used to uncover Korean equity market interactions which are hard to see using any other modern econometric method and which would otherwise had remained hidden.

Findings

The authors observed that Korean equity market is strongly integrated with Asian equity markets at lower frequency scales and has a relatively weak correlation at higher frequencies. Further this correlation eventually grows strong in the interim of crises period at lower frequency scales. The authors, however, do not found any significant deviation in dendrograms generated in data clustering process from wavelet scale 2 to 6 which are associated with four and 64 weeks period, respectively. Overall the findings are relevant and have strong policy and practical implications.

Originality/value

The unique contribution of this paper is that it introduces wavelet clustering analysis to produce a nested hierarchy of similar markets at each frequency level for the first time in finance literature
Older workers: stereotypes and occupational self-efficacy
Authors: Chiesa Rita , Toderi Stefano , Dordoni Paola , Henkens Kene , Fiabane Elena Maria , Setti Ilaria
Published: September 2016

Purpose

The purpose of this paper is to explore the relationship between organizational age stereotypes and occupational self-efficacy. First, the authors intend to test the measurement invariance of Henkens’s (2005) age stereotypes scale across two age group, respectively, under 50 and 50 years and older. Then, the moderator role of age groups in the relationship between age stereotypes and occupational self-efficacy is investigated.

Design/methodology/approach

The survey involved a large sample of 4,667 Italian bank sector’s employees.

Findings

The results show the invariance of the three dimensional structure of organizational stereotypes towards older workers scale: productivity, reliability and adaptability. Furthermore, the moderation is confirmed: the relationship between organizational age stereotypes and occupational self-efficacy is significant only for older respondents.

Research limitations/implications

Future studies should aim to replicate the findings with longitudinal designs.

Practical implications

The study suggests the importance to emphasize the positive characteristics of older workers and to reduce the presence of negative age stereotypes in the workplace, especially in order to foster the occupational self-efficacy of older workers.

Originality/value

The findings are especially relevant in view of the lack of evidence about the relationship between age stereotypes and occupational self-efficacy.
Do women only talk about “female issues”? Gender and issue discussion on Twitter
Authors: Evans Heather
Published: September 2016

Purpose

Recent research has shown that female US House candidates were more likely to talk about so-called “female issues” on Twitter during the 2012 election (Evans and Clark, 2015). In this paper, the author extends this former work by investigating the Twitter activity of all US House representatives during their 2012 election and seven months later (June and July of 2013). The purpose of this paper is to show that women do talk more about “female issues” than men, but do not only focus on these issues.

Design/methodology/approach

This paper content analyzes the tweets sent by female and male representatives in the 113th Congress during their 2012 elections, and seven months later.

Findings

Female representatives spend significantly more time devoted to “female issues” on Twitter than male representatives, but their time is not dominated entirely by “female issues.” Even though the difference is not statistically significant, women sent more tweets about “male issues” than men both during and after the 2012 election. Women tweet more than men about “women,” but they also care about business issues, as is evidenced by that issue being one of the most discussed on Twitter by female representatives during both the election and seven months later.

Originality/value

Unlike other studies on gender and issue discussion, this paper examines a new type of communication: Twitter. Tweets are split by issue type (female/male) and the author sees that while women do discuss “female issues” more than men, they do not exclude “male issues.” This paper also shows that women focus on “female issues” both during elections and after.
Innovating with STEAM in middle school classrooms: remixing education
Authors: Herro Danielle , Quigley Cassie
Published: September 2016

Purpose

This paper aims to broaden the conversation regarding STEAM by investigating the new form of education. The novelty of science, technology, engineering, art and mathematics (STEAM) instruction in K-12 classrooms means few cases of STEAM teaching are documented in depth.

Design/methodology/approach

As part of a larger multi-year study researching STEAM teaching practices in 14 middle school classrooms in the southeastern USA, the article first summarizes prior research findings and then presents ideas for higher education and K-12 researchers to consider when incorporating STEAM teaching in pre-service education, professional development and in classrooms. Then, the authors use a second-order narrative approach to describe three cases of teachers enacting STEAM practices in classrooms.

Findings

Drawing on the notion of “remixing” education in the context of STEAM, the authors show how each teacher alters existing practices, instead of offering entirely new instruction, as they implement STEAM teaching.

Originality/value

With few cases of STEAM teaching detailed in the depth, this paper advances the understanding of STEAM teaching practices in K-12 classrooms.
Mind the metaphor: charting the rhetoric about introductory programming in K-12 schools
Authors: Burke Quinn
Published: September 2016

Purpose

The purpose of this article is to review and discuss the varied ways computer programming is introduced to schools and families as a new form of learning. The paper examines the rhetoric around coding within academic journals and popular media articles over the past three decades. This article argues that despite the best intentions of media researchers and enthusiasts, if the rhetoric around computer science (CS) in all K-12 schools is to become a reality, there first needs to be a greater focus on monitoring such rhetoric and better understanding exactly how programming is presented to the wider public.

Design/methodology/approach

This paper represents an analysis of 67 peer-reviewed books and journal articles as well as news articles and editorials related to students’ learning (or needing to learn) computer programming on the K-12 level. In terms of criteria for inclusion, in addition to publication date and article readership, there were three considerations: the article needed to focus on CS on the K-12 grade levels; the article needed to focus on introductory computer programming initiatives, rather than more advanced courses/topics); the article needed to specifically focus on school-based learning environments.

Findings

Findings point to three distinct ways in which introductory coding initiatives have been portrayed (and been perceived): new literacy, “grounded” math and technical skill. Ultimately, the paper does not propose a single defining metaphor. Rather it argues that the metaphors one selects matter considerably in determining programming’s future in entering (or not entering) schools, and that educators need to make a conscientious effort to consider multiple metaphors without choosing just one.

Research limitations/implications

In terms of research limitations, the article does not purport to be an exhaustive analysis of all the metaphors that have been used to introduce CS to K-12 schools over the past 30 years. Rather it only identifies the leading metaphors from the literature, and in doing so, makes an important first step in examining the role of metaphor in the presentation of CS as a “new” course of study.

Practical implications

The article is intended for educators, researchers and administrators to gain a better understanding of what CS is (and could be) for K-12 schooling.

Social implications

The article is intended for educators, researchers and administrators to likewise understand how they, themselves, can present CS to students and families as a potential course of study.

Originality/value

There is currently considerable discussion about teaching CS in all US high schools, middle schools and even elementary schools. There is however little examination of past attempts to bring CS into K-12 schools and what these attempts may inform current advocacy.
Can incidental sighting data be used to elucidate habitat preferences and areas of suitable habitat for a cryptic species?
Authors: HAUSER Wesley R. , HEISE‐PAVLOV Sigrid R.
Published: September 2016

The involvement of communities in ecological studies has been shown to augment conservation efforts, especially for cryptic species. However, there is a lack of studies addressing the utility of incidental sighting records from community members in gaining knowledge on habitat preferences and distribution of suitable habitat for these organisms. This study compares preferences of the Lumholtz's tree kangaroo (Dendrolagus lumholtzi; LTK), a cryptic rainforest folivore in northeastern Australia, for various habitat and climatic variables derived from data collected during scientific projects to those derived from incidental sighting records using ArcGIS and Maxent. Incidental sighting records suggest that the species uses a wider range of altitudes, annual rainfalls, annual mean temperatures and vegetation types than predicted by scientific studies. Incidental records also show that the species can persist in areas of lower rainfall during the wettest month and lower minimum temperature during the coldest month. Both data place the species within a comparable range of rainfalls during the driest month, maximum temperatures of the warmest month and soil types. When using identified preferences to assess the extent and distribution of suitable habitat, incidental records predicted more areas of suitable habitat than scientific records with an overlap of up to 91% between them. The present study proves that incidental sighting records can be a valuable part of the study of cryptic species and should be considered complementarily alongside scientific studies to obtain comprehensive ecological information of a species that can assist in its conservation.
Phenolic Profiles, Antioxidant Activities, and Neuroprotective Properties of Mulberry (Morus atropurpurea Roxb.) Fruit Extracts from Different Ripening Stages
Authors: Yang Jiufang , Liu Xuanjun , Zhang Xiaoxu , Jin Qing , Li Jingming
Published: September 2016

The present work investigated the phenolic profiles (including nonanthocyanin and anthocyanin phenolics), antioxidant activities, and neuroprotective potential of mulberry fruit (MF) (Morus atropurpurea Roxb.) grown in China at different ripening stages. High‐performance liquid chromatography‐tandem mass spectrometry method (HPLC‐MS/MS) was used to identify and quantify the phenolic compounds. The antioxidant capacity, total phenolic content (TPC), total flavonoid content (TFC), and total monomeric anthocyanin content (TAC) were determined using spectrophotometric methods. The neuroprotective effects of MFs at different ripening stages were investigated using Aβ25‐35‐treated PC12 cells as the cellular model of Alzheimer's disease. Of the 19 phenolic compounds characterized from the MF extracts, the contents of rutin and anthocyanins increased and that of chlorogenic acid decreased significantly with maturity. At the fully ripened stage, MF extracts showed the highest amounts of TPC (11.23 mg gallic acid equivalents/g fresh weight), TFC (15.1 mg rutin equivalents/g fresh weight), and TAC (1177 mg cyanidin 3‐O‐glucoside equivalents/100 g fresh weight). Meanwhile, antioxidant activity of MF extracts at this stage was highest according to ABTS (an IC50 value of 4.11 μg/mL) and DPPH (an IC50 value of 10.08 μg/mL) assays. Cellular assays revealed increased cell viability in cells treated with the ripe MF extracts; compared with the control groups, the ripening fruits also increased the antioxidant enzyme levels in PC12 cells. Together, these results suggest that the antioxidant activities and neuroprotective properties of ripening MFs are related to the contents and types of phenolic compounds that are present in the fruits.
Rainforest seed rain into abandoned tropical Australian pasture is dependent on adjacent rainforest structure and extent
Authors: Charles Lachlan S. , Dwyer John M. , Mayfield Margaret M.
Published: September 2016

It is well known that the recovery of abandoned tropical pastures to secondary rainforest benefits from the arrival of seeds from adjacent rainforest patches. Less is known, however, about how the structural attributes of adjacent rainforest (e.g. tree density, canopy cover and tree height) impact seed rain patterns into abandoned pastures. Between 2011 and 2013, we used seed traps and ground seed surveys to track the richness and abundance of rainforest seeds entering abandoned pastures in Australia's wet tropics. We also tested how seed rain diversity is related to the distance from forest, the proportion of forest cover in the landscape and several structural attributes of adjacent forest patches, specifically average tree height, canopy cover, tree species richness and density. Almost no seeds were captured in elevated pasture seed traps, even near forest remnants. Abundant forest seeds were found in ground surveys but only within 10 m of forest edges. In ground surveys, seeds from wind‐dispersed species were more abundant, but less species rich, than animal‐dispersed species. A survey of pasture seedling recruits suggested that some forest seeds must be dispersing more than 10 m into pasture at very low frequencies, but only a few species are establishing there. Recruits were predominantly animal‐dispersed not wind‐dispersed species. In addition to distance from forest and the proportion of forest within a 100‐ to 200‐m radius of sampling sites, the richness and density of adjacent forest trees were the most important factors for explaining the probability of seed occurrence in abandoned pastures. Results suggest that without some restoration assistance, the recovery of abandoned pastures into secondary rainforest in Australia's tropical rainforests will likely be limited, at least in part, by a very low rate of seed dispersal away from forest edges and by the diversity and density of trees in adjacent remnant forests.
Systematic review shows that pathological lead points are important and frequent in intussusception and are not limited to infants
Authors: Fiegel Henning , Gfroerer Stefan , Rolle Udo
Published: September 2016

Intussusception is the most clinically relevant cause of bowel obstruction in infancy and can be idiopathic or occur as a result of pathological lead points. The incidence of these pathological lead points varies from 0.3 to 20%, and they can be mucosal, intramural or extrinsic structures. A systematic literature review was performed from 1998 to 2016 to evaluate the incidence and types of pathological lead points in paediatric intussusception, and this identified 31 epidemiological and retrospective case cohort studies, reviews and case reports.

Conclusion: Pathological lead points were frequent in intussusceptions and not limited to infants.
Impact of Sulfatase‐2 on cancer progression and prognosis in patients with renal cell carcinoma
Authors: Kumagai Shin , Ishibashi Kei , Kataoka Masao , Oguro Toshiki , Kiko Yuichirou , Yanagida Tomohiko , Aikawa Ken , Kojima Yoshiyuki
Published: September 2016

Heparan sulfate‐specific endosulfatase‐2 (SULF‐2) can modulate the signaling of heparan sulfate proteoglycan‐binding proteins. The involvement of SULF‐2 in cancer growth varies by cancer type. The roles of SULF‐2 expression in the progression and prognosis of renal cell carcinomas (RCC) have not yet been fully clarified. In the present study, the expression levels of SULF‐2 mRNA and protein in 49 clinical RCC samples were determined by RT‐PCR and immunostaining. The existence of RCC with higher SULF‐2 expression and lower SULF‐2 expression compared to the adjacent normal kidney tissues was suggested. High SULF‐2 expression was correlated with an early clinical stage and less invasive pathological factors. Low SULF‐2 expression was correlated with an advanced stage and higher invasive factors. Three‐year cancer‐specific survival (CSS) for high SULF‐2 RCC and low SULF‐2 RCC were 100% and 71.4%, respectively (log‐rank P = 0.0019), with a significantly shorter CSS observed in low SULF‐2 RCC patients. The influence of SULF‐2 expression level on Wnt/VEGF/FGF signaling, cell viability and invasive properties was examined in three RCC cell lines, Caki‐2, ACHN and 786‐O, using a SULF‐2 suppression model involving siRNA or a SULF‐2 overexpression model involving a plasmid vector. High SULF‐2 expression enhanced Wnt signaling and Wnt‐induced cell viability, but not cell invasion. In contrast, low levels of SULF‐2 expression significantly enhanced both cell invasion and viability through the activation of VEGF/FGF pathways. RCC with lower SULF‐2 expression might have a higher potential for cell invasion and proliferation, leading to a poorer prognosis via the activation of VEGF and/or FGF signaling.