bluuebunny/crossref_metadata_2025_split huggingface dataset:
A wave interaction approach to studying non-modal homogeneous and stratified shear instabilities
Authors: Guha Anirban , Lawrence Gregory A. 
Published: August 2014

AbstractHomboe (Geophys. Publ., vol. 24, 1962, pp. 67–112) postulated that resonant interaction between two or more progressive, linear interfacial waves produces exponentially growing instabilities in idealized (broken-line profiles), homogeneous or density-stratified, inviscid shear layers. Here we have generalized Holmboe’s mechanistic picture of linear shear instabilities by (i) not initially specifying the wave type, and (ii) providing the option for non-normal growth. We have demonstrated the mechanism behind linear shear instabilities by proposing a purely kinematic model consisting of two linear, Doppler-shifted, progressive interfacial waves moving in opposite directions. Moreover, we have found a necessary and sufficient (N&S) condition for the existence of exponentially growing instabilities in idealized shear flows. The two interfacial waves, starting from arbitrary initial conditions, eventually phase-lock and resonate (grow exponentially), provided the N&S condition is satisfied. The theoretical underpinning of our wave interaction model is analogous to that of synchronization between two coupled harmonic oscillators. We have re-framed our model into a nonlinear autonomous dynamical system, the steady-state configuration of which corresponds to the resonant configuration of the wave interaction model. When interpreted in terms of the canonical normal-mode theory, the steady-state/resonant configuration corresponds to the growing normal mode of the discrete spectrum. The instability mechanism occurring prior to reaching steady state is non-modal, favouring rapid transient growth. Depending on the wavenumber and initial phase-shift, non-modal gain can exceed the corresponding modal gain by many orders of magnitude. Instability is also observed in the parameter space which is deemed stable by the normal-mode theory. Using our model we have derived the discrete spectrum non-modal stability equations for three classical examples of shear instabilities: Rayleigh/Kelvin–Helmholtz, Holmboe and Taylor–Caulfield. We have shown that the N&S condition provides a range of unstable wavenumbers for each instability type, and this range matches the predictions of the normal-mode theory.
Second-order perturbation of global modes and implications for spanwise wavy actuation
Authors: Tammisola O. , Giannetti F. , Citro V. , Juniper M. P. 
Published: August 2014

AbstractSensitivity analysis has successfully located the most efficient regions in which to apply passive control in many globally unstable flows. As is shown here and in previous studies, the standard sensitivity analysis, which is linear (first order) with respect to the actuation amplitude, predicts that steady spanwise wavy alternating actuation/modification has no effect on the stability of planar flows, because the eigenvalue change integrates to zero in the spanwise direction. In experiments, however, spanwise wavy modification has been shown to stabilize the flow behind a cylinder quite efficiently. In this paper, we generalize sensitivity analysis by examining the eigenvalue drift (including stabilization/destabilization) up to second order in the perturbation, and show how the second-order eigenvalue changes can be computed numerically by overlapping the adjoint eigenfunction with the first-order global eigenmode correction, shown here for the first time. We confirm the prediction against a direct computation, showing that the eigenvalue drift due to a spanwise wavy base flow modification is of second order. Further analysis reveals that the second-order change in the eigenvalue arises through a resonance of the original (2-D) eigenmode with other unperturbed eigenmodes that have the same spanwise wavelength as the base flow modification. The eigenvalue drift due to each mode interaction is inversely proportional to the distance between the eigenvalues of the modes (which is similar to resonance), but also depends on mutual overlap of direct and adjoint eigenfunctions (which is similar to pseudoresonance). By this argument, and by calculating the most sensitive regions identified by our analysis, we explain why an in-phase actuation/modification is better than an out-of-phase actuation for control of wake flows by spanwise wavy suction and blowing. We also explain why wavelengths several times longer than the wake thickness are more efficient than short wavelengths.
REVERSE MATHEMATICS OF FIRST-ORDER THEORIES WITH FINITELY MANY MODELS
Authors: BELANGER DAVID R. 
Published: August 2014

AbstractWe examine the reverse-mathematical strength of several theorems in classical and effective model theory concerning first-order theories and their number of models. We prove that, among these, most are equivalent to one of the familiar systems RCA0, WKL0, or ACA0. We are led to a purely model-theoretic statement that implies WKL0 but refutes ACA0 over RCA0.
Quantitative super-resolution imaging of Bruchpilot distinguishes active zone states
Authors: Ehmann Nadine , van de Linde Sebastian , Alon Amit , Ljaschenko Dmitrij , Keung Xi Zhen , Holm Thorge , Rings Annika , DiAntonio Aaron , Hallermann Stefan , Ashery Uri , Heckmann Manfred , Sauer Markus , Kittel Robert J. 
Published: August 2014

AbstractThe precise molecular architecture of synaptic active zones (AZs) gives rise to different structural and functional AZ states that fundamentally shape chemical neurotransmission. However, elucidating the nanoscopic protein arrangement at AZs is impeded by the diffraction-limited resolution of conventional light microscopy. Here we introduce new approaches to quantify endogenous protein organization at single-molecule resolution in situ with super-resolution imaging by direct stochastic optical reconstruction microscopy (dSTORM). Focusing on the Drosophila neuromuscular junction (NMJ), we find that the AZ cytomatrix (CAZ) is composed of units containing ~137 Bruchpilot (Brp) proteins, three quarters of which are organized into about 15 heptameric clusters. We test for a quantitative relationship between CAZ ultrastructure and neurotransmitter release properties by engaging Drosophila mutants and electrophysiology. Our results indicate that the precise nanoscopic organization of Brp distinguishes different physiological AZ states and link functional diversification to a heretofore unrecognized neuronal gradient of the CAZ ultrastructure.
Treats: low socioeconomic status Australian parents’ provision of extra foods for their overweight or obese children
Authors: Pescud Melanie , Pettigrew Simone 
Published: August 2014

Issue addressedChild obesity is a global issue, with rates highest among disadvantaged groups. Overconsumption of treats is a contributor to children's weight problems. The objective of this study was to explore low socioeconomic parents' beliefs and behaviours relating to their provision of treat foods for their overweight or obese children.MethodsQualitative methods were used to collect data; these included introspections, interviews and focus groups. A total of 37 parents of overweight or obese children aged between 5 and 9 years took part in the 12‐month study.ResultsMost parents provided their children with treats on a daily basis. Factors affecting parents' provision of treats included parents' desire to control their children's behaviour, to demonstrate love and affection, and to address deprivation beliefs.ConclusionThere is considerable scope for improving these parents' treating behaviours by understanding the relevant factors underpinning their situations and choices.So what?The findings provide an indication of the kinds of health promotion interventions that may be needed to assist in addressing treating behaviours among disadvantaged parents with overweight or obese children.
Relationships between facial temperature changes, end‐exercise affect and during‐exercise changes in affect: A preliminary study
Authors: Legrand Fabien D. , Bertucci William M. , Arfaoui Ahlem 
Published: August 2014

AbstractThe present study was performed as an evaluation of the relationships between changes in facial temperature and self‐reported pleasure–displeasure during an acute aerobic exercise bout. Ninety‐two students performed a 10‐minute long session of cycle ergometry at 80–85% of age‐predicted maximal heart rate. Using infrared thermography and a single‐item measure of pleasure–displeasure (the Feeling Scale, FS), facial temperature and the FS score were sampled at the beginning (Min1:00) and at the end of the exercise session (Min9:00). Statistical analyses revealed that cheek (but not forehead) temperature was higher at the end of the exercise bout compared to Min1:00 (it increased by about 5%). Change in cheek temperature was negatively related to end‐exercise affect (β = −0.28, P < 0.001) and to during‐exercise affective changes (β = −0.35, P < 0.001). No significant relationship with forehead temperature was found. Some of the possible reasons for this differential effect as well as theoretical and practical implications of our findings are discussed.
Random bin picking: has its time finally come?
Authors: Bogue Consultant Robert 
Published: August 2014

Purpose
– This paper aims to provide details of recent developments in random bin picking (RBP) technologies and products, together with an insight into its commercial status and prospects.

Design/methodology/approach
– Following an introduction to RBP, this article discusses the technology, benefits and limitations of RBP. It then considers a number of products and applications and concludes with a brief discussion.

Findings
– This article shows that RBP offers significant economic and operational benefits, but it is a complex technology and applications remain limited. It is underpinned by advanced machine vision and sophisticated image processing algorithms and continues to be the topic of academic research. Many RBP products have been launched in the past but the latest generation of dedicated vision systems, software packages and fully integrated robotic systems suggest that more widespread applications are imminent.

Originality/value
– This paper provides a timely introduction to the rapidly developing field of RBP by discussing the technologies and a range of products and applications.
Non-destructive evaluation of stacking sequence in textile composite: different techniques and experimental verification
Authors: Saboktakin A. , Vu-Khanh T. , Bonnefon Y. 
Published: August 2014

Purpose
– The purpose of this paper is to experimentally investigate the capability of four non-destructive testing (NDT) techniques to detect the layer orientation in textile composite laminates. The aerospace industry has been the primary driving force in the use of textile composites.

Design/methodology/approach
– Woven glass fiber composite samples were inspected using C-scan ultrasonic, vibration analyzer, X-ray micro-tomography and ultraviolet technique. In a complementary study, mechanical testing was carried out to investigate the effect of mid-layer orientation on in-plane tensile strength and their failure modes using microscopic imagining.

Findings
– During C-scan ultrasonic, the high attenuation and scattering of ultrasonic waves caused by the textile fabric layers limited its application to only detect the first layer of samples. Frequency response tests of composite samples were also conducted to investigate the effect of mid-layer orientation on dynamic responses. The same trend was observed in the finite element modeling results with a clear effect of the fiber orientation defect seen in frequency response function response and higher mode shapes. Moreover, the results of micro computed tomography demonstrate that this technique could definitely detect the orientation of each layer; however, X-ray imaging at small scales introduced some challenges. Images obtained from ultraviolet technique did not reveal mid-layer orientation.

Originality/value
– In this paper, the application of different NDT techniques along with finite element modeling to inspect two-dimensional textile composites was presented. Hopefully, the research results presented here will lead to much published papers in inspection of textile composites.
The repeatability positioning analysis of the industrial robot arm
Authors: Kluz Rafał , Trzepieciński Tomasz 
Published: August 2014

Purpose
– The purpose of the following work was to work out the dependency to allow for the determination of the repeatability positioning error value of the robot at any given point in its workspace, without the necessity of conducting time-consuming measurements while routing a precise surface of repeatability positioning.

Design/methodology/approach
– The presented dependency permits for the possibility to determine, even at the planning phase, the optimal connection point in the workspace, ensuring the best parameters for the process of machine assembly, without needless overestimation of precision of the utilized equipment. To solve the task the sequential quadratic programming (SQP) method implemented in the MATLAB(R) environment was used. To verify the hypothesis of the compatibility of the empirical distribution with the hypothetical distribution of the robot’s positioning error, the Kolmogorov test was used.

Findings
– In this paper, it has been demonstrated theoretically and experimentally that the industrial robot accuracy can vary over a very wide range in the workspace. This provides an additional opportunity to increase reliability of the assembly process through the appropriate choice of the point of parts joining. The methodology presented here allows the designer of assembly workstations to rapidly estimate the repeatability of robot positioning and to allocate at the design stage of assembly process the optimal position in the robot workspace to ensure the required precision, without unnecessarily high accuracy of equipment used and, therefore, without inflated costs.

Originality/value
– An alternative solution to the stated problem can be the proposed method for determining the robot’s positioning errors, requiring a much smaller amount of measurements to be taken that would be necessary to determine the parameters of the random variable errors of the joint coordinates of the robot and for their verification by the repeatability of positioning in randomly selected points in the workspace. Additionally discussed in the study, the methodology of identifying connection place was designed for typical combinations of machine parts, most frequently encountered in assembly process and was taken into account, typical limitations occurring in actual manufacturing conditions.
Earnings management around tax rate reduction: evidence from China's 2007 corporate tax reform
Authors: Zeng Tao 
Published: August 2014

Purpose– The purpose of this paper is to examine earnings management around tax rate reduction in the wake of the 2007 corporate tax reform in China.Design/methodology/approach– This paper is an empirical work using a sample of listed Chinese real estate firms.Findings– This study finds that firms managed earnings, including accrual-based earnings management and real earnings management, to decrease income in the fourth quarter of 2007, and to increase income in the first quarter of 2008. It suggests that the real estate firms were shifting income from the fourth quarter of 2007, when the statutory tax rate was 33 per cent, to the first quarter of 2008, when the statutory tax rate was 25 per cent, and therefore saved on tax payments. It also finds that corporate ownership structures, including ownership concentration and state ownership, affect earnings management. In the fourth quarter, state ownership is negatively associated with accrual-based earnings management, while ownership concentration is positively related to both accrual and real earnings management. In the first quarter, state ownership is negatively related to real earnings management.Social implications– Tax authority and policy makers might be interested in evidence on earnings management around tax rate reduction. Changes in tax rates increase the incentives to shift income, which may warrant a closer scrutiny by both outside auditors and tax auditors.Originality/value– This paper is the first study that relates to both accrual-based earnings management and real earnings management to corporate tax rate changes by showing that firms manipulate income upward in the low-tax-rate periods and downward in the high-tax-rate periods.
An integrative approach to eWOM and marketing communications
Authors: Weisfeld-Spolter Suri , Sussan Fiona , Gould Stephen 
Published: August 2014

Purpose
– The purpose of this paper is to improve the understanding of how different forms of electronic word-of-mouth (eWOM) and simultaneous marketing communications (MC), two crucial components of relationship marketing, affect consumer persuasion when presented in a business-to-customer (B2C)-sponsored vs a customer-to-customer (C2C)-sponsored social network site (SNS). A concise typology of eWOM is also proposed.

Design/methodology/approach
– An experiment involving different social network movie sites was conducted testing the effects of different eWOM along with a comparison to MC on consumers’ interest in, and likelihood to watch movie DVDs.

Findings
– The empirical results showed that not all eWOM types have the same persuasiveness and community sponsorship as a source credibility cue is more influential from a C2C-sponsored SNS than from a B2C one, particularly for many-to-one eWOM communications.

Research limitations/implications
– Future research should include both positive and negative types of eWOM using different product categories to increase the generalizability of the results.

Practical implications
– Not all eWOM types are created equal, and thus, SNS sponsorship can lead to source bias and affect the persuasiveness of eWOM embedded in SNSs. The results also imply that not all positive word-of-mouth has a more positive effect than MC.

Originality/value
– The approach of measuring two forms of communications simultaneously adds to the much-needed integrative approach of studying the simultaneous delivery of MC and WOM and provides a more nuanced view of persuasion knowledge.
Exploring the benefits of mentoring activities for the mentor
Authors: Grima François , Paillé Pascal , H. Mejia Jorge , Prud'homme Lionel 
Published: August 2014

Purpose– Mentoring is more and more studied by researchers on account of its professional and personal impact on mentees. This contribution has two main objectives. First, to empirically validate the benefits for the mentor and to test links between mentoring activities and benefits through a multidimensional analysis. Second, to incorporate two variables structuring the relationship into the analysis: the formal vs informal nature of the mentoring relationship and the gender composition of the dyad. The paper aims to discuss these issues.Design/methodology/approach– In total, 161 French managers have been surveyed.Findings– The results show that mentors value the personal dimension of the relationship more than the professional dimension. Moreover, informal mentoring favours the perception of a rewarding experience by the mentor, whereas formal mentoring is synonymous with improved professional performance. This research calls into question the advantage of same-sex dyads, suggesting that heterogeneity favours improved performance.Originality/value– The originality of the paper was to focus on the homogeneity of the mentor-protégé dyad in terms of gender.
Job insecurity and job satisfaction
Authors: Zheng Xingshan , Diaz Ismael , Tang Ningyu , Tang Kongshun 
Published: August 2014

Purpose– The purpose of this paper is to examine optimism and how facets of subordinates’ psychological characteristics, such as their attitudes and personalities, are similar to their direct supervisors’ (as person-supervisor deep-level similarity or P-S deep-level similarity) in order to understand their interactions with job insecurity in predicting employee job satisfaction.Design/methodology/approach– Empirical study had been conducted. Sample firms in this study consist of eight state-run electric power companies and 16 licensed chemical companies in central Hubei Province in China. In total, 368 valid samples were included in the analyses (with a valid return rate of 73 percent). All constructs were rated on a five-point Likert-type response scale. In order to diminish the possibility of common method biases, the authors used participants’ dyad supervisors to rate P-S deep-level similarity and P-S guanxi. The authors tested the hypotheses by implementing hierarchical linear regression.Findings– The results show that when certain demographic variables (e.g. age, gender, education, post, employment type, income proportion, position) and P-S guanxi are controlled, optimism and P-S deep-level similarity significantly interact with job insecurity to predict job satisfaction. Job satisfaction is bolstered when job security increases among those who report a high level of both optimism and P-S deep-level similarity.Originality/value– Researchers have found that job insecurity has negative effects on job satisfaction (Sverkeet al., 2002). But there is a lack of understanding about the mechanism of how job insecurity affects job satisfaction. In this study, the authors found that optimism and P-S deep level similarity could jointly moderate the relation (and direction) between job insecurity and job satisfaction. The work illustrates how positive traits (such as optimism) and psychological factors (such as P-S deep-level similarity) could affect employee job satisfaction with different levels of job insecurity.
Aspirations and occupational achievements of Dutch fathers and mothers
Authors: van der Horst Mariska , van der Lippe Tanja , Kluwer Esther 
Published: August 2014

Purpose– The purpose of this paper is to investigate how work and family aspirations relate to occupational achievements and gender differences herein.Design/methodology/approach– Using data from 2009 the authors examined the relationship between career and childrearing aspirations and occupational achievements of Dutch parents. Using path modeling in Mplus, the authors investigated both direct and indirect pathways where aspirations were related to occupational achievements via time allocations.Findings– The authors found that ranking being promoted instead of a non-career aspiration as the most important job aspiration was positively related to occupational achievements. Surprisingly, the authors also found that ranking childrearing as the most important life role aspiration was positively related to earnings among fathers.Research limitations/implications– Investigating aspirations in multiple domains simultaneously can provide new information on working parents’ occupational achievements.Practical implications– The results imply that parents who want to achieve an authority position or high earnings may need to prioritize their promotion aspiration among their job aspirations in order to increase the likelihood of achieving such a position. Moreover, this is likely to require sacrifices outside the work domain, since spending more time on paid work is an important way to achieve this aspiration.Originality/value– This paper adds to previous research by explicitly taking life role aspirations into account instead of focussing solely on job aspirations. Moreover, this study extends previous research by investigating indirect pathways from aspirations to occupational achievements via family work in addition to the previously found pathway via paid work.