bluuebunny/crossref_metadata_2025 huggingface dataset:
Moving Up! Or Down? Mathematics Anxiety in the Transition From Elementary School to Junior High
Authors: Klee Holly L. , Miller Angela D.
Published: January 2019

Mathematics anxiety negatively impacts cognitive processing, performance, expectations, motivation, and future choices. However, research has not examined patterns in students’ mathematics anxiety levels over time. The current study addresses this gap by exploring group-based trajectories in mathematics anxiety during the transition to junior high school. Five trajectories are described: consistently low anxiety, consistently high anxiety, steady decline, summer decrease, and summer increase. Predictors of trajectory membership, including student demographics and motivational variables like self-concept, are explored. Trajectory membership predicts longitudinal differences in expectations and values after high school. Implications for research on students’ mathematics anxiety over time and especially during transition are discussed.
Cancer Screening Markers: A Simple Strategy to Substantially Reduce the Sample Size for Validation
Authors: Baker Stuart G.
Published: January 2019

Background. Studies to validate a cancer prediction model based on cancer screening markers collected in stored specimens from asymptomatic persons typically require large specimen collection sample sizes. A standard sample size calculation targets a true-positive rate (TPR) of 0.8 with a 2.5% lower bound of 0.7 at a false-positive rate (FPR) of 0.01 with a 5% upper bound of 0.03. If the probability of developing cancer during the study is P = 0.01, the specimen collection sample size based on the standard calculation is 7600. Methods. The strategy to reduce the specimen collection sample size is to decrease both the lower bound of TPR and the upper bound of FPR while keeping a positive lower bound on the anticipated clinical utility. Results. The new sample size calculation targets a TPR of 0.4 with a 2.5% lower bound of 0.10 and an FPR of 0.0 with a 5% upper bound of 0.005. With P = 0.01, the specimen collection sample size based on the new calculation is 1800 instead of 7600. Limitations. The new sample size calculation requires a minimum benefit/cost ratio (number of false positives traded for a true positive). With P = 0.01, the minimum cost-benefit ratio is 5, which is plausible in many studies. Conclusion. In validation studies for cancer screening markers, the strategy can substantially reduce the specimen collection sample size, substantially reducing costs and making some otherwise infeasible studies now feasible.
Potential value of non-echo-planar diffusion-weighted imaging of the nasopharynx: a primary study for differential diagnosis between recurrent nasopharyngeal carcinoma and post-chemoradiation fibrosis
Authors: Huang Wenhui , Liu Jing , Zhang Bin , Liang Long , Luo Xiaoning , Mei Yingjie , Zhang Shuixing
Published: January 2019

Background

Distinguishing recurrent nasopharyngeal carcinoma (rNPC) from post-therapeutic inflammatory changes remains a challenging clinical problem.

Purpose

To qualitatively and quantitatively evaluate image quality and compare the diagnostic value of non-echo-planar diffusion-weighted imaging (DWI) based on turbo spin-echo (TSE) and echo-planar imaging (EPI), to distinguish rNPC from post-chemoradiation fibrosis.

Material and Methods

Twenty-seven patients with newly diagnosed rNPC and 35 with biopsy-proven post-chemoradiation fibrosis were categorized into tumor and fibrosis groups, respectively. All patients underwent TSE and EP-DWI on a 3-T magnetic resonance unit. The image quality, lesion conspicuity, and distortions of the EPI and TSE images were qualitatively evaluated by two radiologists. The apparent diffusion coefficient values (ADCs), signal-to-noise ratios (SNRs), and contrast-to-noise ratios (CNRs) of the two sequences were also compared.

Results

The image quality scores indicated that TSE significantly improved image quality and reduced distortion of the nasopharyngeal lesions. Its SNR was slightly lower and CNR was significantly higher than those of EPI. The mean ADCs of the rNPC and post-chemoradiation fibrosis groups showed a significant difference in both sequences ( P < 0.001). However, the ADCs of rNPC on EP-DWI showed a wide variation and more importantly, they appreciably overlapped with those of post-chemoradiation fibrosis. The area under the curve was 0.932 in TSE, which was significantly larger than 0.835 in EPI.

Conclusions

The images of nasopharyngeal lesions obtained with TSE-DWI were of better quality and higher diagnostic capability than those obtained with EP-DWI for differential diagnosis between rNPC and post-treatment sequelae.
Short-term effect of intravitreal conbercept injection on major and macular branch retinal vein occlusion
Authors: Tao Yuan , Huang Chao , Liu Min , Sun Liyuan , Li Linlin , Wei Yuhua , Yu Xiaoting , Wang Hong
Published: January 2019

Objective

To evaluate the effectiveness of intravitreal conbercept injection on major and macular branch retinal vein occlusion (BRVO).

Methods

This retrospective analysis involved 43 patients with BRVO (major BRVO n = 24; macular BRVO, n = 19) who were diagnosed by fluorescein fundus angiography (FFA) and injected with intravitreal conbercept. The following outcomes were measured at baseline and follow-up (1-6 months): best-corrected visual acuity (BCVA), central foveal thickness (CFT), total retinal volume in a 6-mm diameter section of the macula, choroidal thickness under the central fovea of the macula, relative area of retinal hemorrhage, complications, and times when repeated injection was performed.

Results

There were significant differences between the two groups in terms of BCVA, CFT, and total retinal volume in a 6-mm diameter section of the macula at 6 months after treatment. Choroidal thickness under the central fovea of the macula and relative area of retinal hemorrhage showed no significant differences between the two groups at 6 months after treatment; however, they significantly differed from baseline measurements.

Conclusion

In general, intravitreal injection of conbercept may have a better short-term effect in patients with macular BRVO than in patients with major BRVO.
Stress distribution in a mandibular premolar after separated nickel-titanium instrument removal and root canal preparation: a three-dimensional finite element analysis
Authors: Ni Na , Ye Jing , Wang Liyuan , Shen Simin , Han Lei , Wang Yuxia
Published: January 2019

Objective

This study used finite element analysis (FEA) to assess the von Mises stresses of a mandibular first premolar after removing a separated instrument with an ultrasonic technique.

Methods

FEA models of the original and treated mandibular first premolar were reconstructed, and three models (the original canal, size 30/taper 0.04 canal, and separated instrument removal canal) were created. Two-direction (vertical and lateral) loading patterns were simulated with a 175-N force. The maximum von Mises stresses of the models within the roots from the apex to the cervical region were collected and summarized.

Results

Under vertical and lateral loads, all maximal values in the three models were localized in the straight-line access region. Compared with the original model (model 1), the treated models (models 2 and 3) had greater maximum stress values from the apex to the cervical region. Greater differences in the maximum von Mises stresses between models 2 and 3 were present in the straight-line access region.

Conclusions

Separated instrument removal caused changes in stress distribution and increases in stress concentration in the straight-line access region of roots.
Spreadsheet computations of a symmetric double wedge airfoil in supersonic flow
Authors: Keith TG , Cioc S , Jiang H
Published: January 2019

In this paper, the virtues of spreadsheet computation are demonstrated by determining the well-known lift and drag characteristics of a symmetric double wedge airfoil in supersonic flow. The computations require the use of shock-expansion theory of gas dynamics. This determination is a standard problem in gas dynamics that, while simple in nature, involves considerable computation. Spreadsheet solvers greatly diminish this effort and allow students to focus more on the physics of the problem. Moreover, they enable students to explore the problem in more detail.
An effective teaching strategy for engineering mechanics to develop structural optimization modeling skills of undergraduates
Authors: Huang Zhiliang , Wen Mingcai , Yang Tongguang , Fan Bin
Published: January 2019

In this paper, a teaching strategy which effectively enhances the students’ ability to solve practical problems is developed, and thus it can provide a potential tool for engineering mechanics teaching. Through organically integrating optimization theory into mechanics modeling, students’ skill of structural optimization modeling is improved, which help them understand basic concepts involved in mechanics and mathematics and master a general method for practical problem solving. The corresponding course unit is designed to instruct students to perform structural optimization modeling for a series of similar but non-identical mechanics problems, which can motivate them to actively explore the essential relationship between mechanics equations and mathematical models. The effectiveness of the proposed strategy is demonstrated by the “six principles” for designing thought-revealing activities and the feedback from all participants in the course.
Understanding the meaning and use of occupational engagement: Findings from a scoping review
Authors: Black Melissa H , Milbourn Ben , Desjardins Kyle , Sylvester Victoria , Parrant Kimberley , Buchanan Angus
Published: January 2019

Introduction

It is theorized that occupational therapy practice is underpinned by the construct of occupational engagement, with a focus on examining the subjective meaning of occupation. The theoretical definition of occupational engagement presents significant challenges to its use, evaluation, and measurement within evidence-based contemporary occupational therapy practice.

Method

A scoping review was conducted to examine how occupational engagement is defined within occupational therapy literature and how occupational engagement is evaluated.

Results

Twenty-six journal articles were identified. Definitions were fragmented and inconsistent across studies. Key themes relating to definitions of occupational engagement included active involvement in occupation, finding value and meaning, balanced engagement, subjective experience of engagement, developing identity through occupation, and social and environmental interactions. Measures seeking to understand occupational engagement were varied across studies, with a consistent measure applied only in the area of mental health.

Conclusion

The lack of consistency in definitions and measurement of occupational engagement presents significant issues for occupational therapy practice and evaluation. There is a need for a common definition of occupational engagement to be applied in the literature. Outcome measures seeking to understand occupational engagement are also required; however, these rely on a clearly defined construct.
Epidural Morphine by the Thoracic or Lumbar Routes in Cholecystectomy. Effect on Postoperative Pain and Respiratory Variables
Authors: Hakanson E. , Bengtsson M. , Rutberg H. , Ulrick A. M.
Published: January 2019

Thirty-seven women undergoing elective cholecystectomy were randomised into two groups, receiving either lumbar epidural morphine (group L) or epidural morphine via the thoracic route (group T). The effect on pain relief was assessed by a visual analogue scale and included both resting pain and ‘provoked’ pain. Respiratory parameters (PEF, FEVI and FVC) were also studied. The patients were investigated preoperatively, and 4, 6, 12 and 24 hours after the start of surgery. No significant difference was observed between the groups concerning pain relief or respiratory performance. We conclude that after cholecystectomy lumbar epidural morphine is as effective as thoracic epidural morphine in relieving postoperative pain.
Patient-Controlled Analgesia in Children
Authors: Gaukroger P. B. , Tomkins D. P. , van der Walt J. H.
Published: January 2019

The use of patient-controlled analgesia is described for forty children who had undergone major orthopaedic or general surgery. Ages ranged from 6 to 18 years (mean 11.4 years) and PCA was used for an average of 46.2 hours postoperatively. Morphine requirements overall averaged 40.5 μg/kg/hr (SD 22.6). Requirements for the first six hours were not significantly different to a similar period 24 hours later. There was a large individual variation for patients undergoing similar procedures.

Patients undergoing scoliosis surgery required significantly more morphine than any other group of patients. Problems with patient-controlled analgesia have been of a minor nature. We conclude that patient-controlled analgesia is a suitable and safe method of pain relief for paediatric patients and that the lower age limit is that at which a child can understand the concept after suitable explanation. In this study children as young as six years were able to successfully use the method.
For the Record
Authors: Dwyer Brian Eric , Horan B. F.
Published: January 2019

The New South Wales Anaesthetics Continuing Education Committee conducted their 23rd meeting in Sydney on April 7–8, 1989. This was titled ‘Local Anaesthesia and Acute Pain’ and dedicated to the honour of Brian Dwyer who will retire from an illustrious clinical career early in 1990. We record the foreword to the proceedings of the meeting and addresses given at the associated dinner for the benefit of those whose lives and practice have been touched, whether they are aware of it or not, by a great anaesthetist and a great man.
CGRP ligand and receptor monoclonal antibodies for migraine prevention: Evidence review and clinical implications
Authors: Dodick David W
Published: January 2019

Background: Monoclonal antibodies that target calcitonin gene-related peptide or the canonical calcitonin gene-related peptide receptor have emerged as effective and well tolerated for the preventive treatment of migraine. These large molecules appear ideally suited for migraine prevention. They have an extended biological half-life, are administered either monthly or quarterly either by subcutaneous injection or intravenous infusion, require minimal or no dose-titration and have the potential for a rapid onset of effect compared to conventional oral preventive drugs. There is high selectivity and they target an important mediator in the pathogenesis of migraine. Investigation: Phase II and pivotal phase III studies have all yielded positive results with a favorable adverse event profile. No serious treatment-related adverse outcomes have thus far been reported in controlled or long-term open-label extension studies. This tolerability profile promises to improve adherence and, possibly, long-term outcomes. Conclusions: Calcitonin gene-related peptide monoclonal antibodies are effective and well tolerated for the preventive treatment of migraine. They have distinct advantages over currently available oral preventive drugs. While treatment-related serious adverse events have not been observed in open-label extension studies, long-term outcomes and safety will require broad exposure in heterogeneous patient populations in clinical practice. In addition, their safety in women, especially during pregnancy, will require longitudinal surveillance. Given the overlapping mechanism(s), the effectiveness of existing (triptans) and emerging (calcitonin gene-related peptide receptor antagonists) acute therapies in those using a calcitonin gene-related peptide mAb will require further study.
Impact of Traffic Volume on Pavement Macrotexture and Skid Resistance Long-Term Performance
Authors: Plati Christina , Pomoni Maria
Published: January 2019

Pavement skid resistance is influenced by both pavement macrotexture and microtexture, with the two components providing the skid resistance properties required to assist in ensuring road safety. In addition to these factors the cumulative traffic along a pavement is a known determinant factor influencing pavement surface characteristics leading to deterioration. However, previous research efforts in this area have been evaluated based on laboratory experiments that have not proven to be easily extrapolated to represent field conditions. With this in mind, the present study aims to investigate and comprehend the long-term effect of cumulative traffic on both skid resistance and macrotexture evolution based on actual field measurements. The ultimate research goal is to develop a practical approach for analysis and interpretation of in-situ performance characteristics that could be utilized by road agencies in evaluating long-term skid resistance performance. For the investigation, an 11-year field dataset consisting of three categories of pavement sections defined by their traffic volume/characteristics and geometric design was analyzed. The analysis results showed that skid resistance and macrotexture can be separated into two defined zones during their evolution, which are determinant for the remainder of the pavement service-life. In addition, the varying characteristics of the three investigated cases were presented and a sensitivity analysis performed. Overall, knowledge gained from understanding the long-term field pavement performance can provide valuable information to road agencies for on-time pavement maintenance actions that can help ensure pavement sustainability.
Development of an Improved Test Setup for Measuring the Resilient Modulus of Stabilized Pavement Materials
Authors: Louw Stefan , Wu Rongzong , Hammack Joseph , Jones David
Published: January 2019

In a recent study to develop mechanistic empirical relationships for full depth reclamation (FDR) in California, it was determined that the commonly used triaxial testing setup detailed in American Association of State Highway and Transportation Officials (AASHTO) T 307 was not suitable for testing stabilized materials. This paper investigates different testing setups, based on a comprehensive literature review, to determine an appropriate approach for measuring strains on both laboratory-compacted and field-cored specimens. Five different test setups were evaluated, ranging from measurements on the top cap of the triaxial cell, to third-point measurements on the specimen. This study also investigated methods of mounting transducer gauge points on the specimen in a repeatable and accurate manner, and for preparing the specimen ends to mitigate point loads. Two field cores, one sampled from an FDR project with cement stabilization (FDR-PC) and the other from an FDR project with foamed asphalt stabilization (FDR-FA), were subjected to unconfined, low stress cyclic triaxial testing using different deviatoric and seating stresses using each of the five test setups. The effects of non-linear strain distribution on the cyclic stress strain curves were compared. Based on these results, the recommended test setup for determining the resilient modulus of the stabilized material is the third point on-specimen setup for measuring strain. This approach was minimally influenced by the non-linear strain distribution, and provided resilient moduli that closely correlated with stiffnesses back calculated from the falling weight deflectometer deflections measured close to the core locations.
Factors Affecting the Adoption of Autonomous Vehicles for Commute Trips: An Analysis with the 2015 and 2017 Puget Sound Travel Surveys
Authors: Wang Kailai , Akar Gulsah
Published: January 2019

The emergence of autonomous vehicles (AVs) may shape the future landscape of urban mobility. Although there is a growing literature on public opinions with regard to self-driving, little attention has been explicitly given to the commuters and their preferences for their commute trips. Using data from the 2015 and 2017 Puget Sound Regional Household Travel Studies, this study investigates the factors associated with employees’ propensity for using AVs. We develop a bivariate ordered probit model to jointly estimate the determinants of levels of interest in (i) commuting alone using AVs and (ii) commuting with others using shared AVs. Not surprisingly, it was found that current solo drivers are more likely to commute alone using AVs compared with other mode users. Significant differences were not found between current drivers and other commuters when it comes to the potential use of shared AVs. The results also reveal that, controlling for other factors, commuters surveyed in 2017 are less likely to be interested in shared AVs compared with their 2015 counterparts. The conclusion is that more planning efforts are needed to support the market penetration of shared AVs.
Glare Screen Use in Road Design: A Synthesis of the Practice
Authors: Johnson Daniel T. , McDonald David R.
Published: January 2019

In 2011, TRB Geometric Design Committee (AFB10) drafted a research needs statement to complete an updated synthesis of the practice to the 1979 Glare Screen Guidelines, Synthesis of Highway Practice. This study completes the efforts of the 2011 research needs statement on glare screens and their use in road design. The research identifies the uses and types of glare screen in road design, examines national-level glare screen guidance, and provides a summary of the findings from 30 transportation agencies in the United States.
Pavement Structural Capacity from Traffic Speed Deflectometer for Network Level Pavement Management System Application
Authors: Nasimifar Mahdi , Thyagarajan Senthilmurugan , Chaudhari Sarah , Sivaneswaran Nadarajah
Published: January 2019

Structural number (SN) represents the structural capacity of a flexible pavement system to sustain anticipated traffic and is among the structural indices most commonly used by pavement design engineers in the U.S. Effective structural number (SNeff) is an indicator of structural capacity of in-service pavement sections and is conventionally estimated from nondestructive testing (NDT) device data such as falling weight deflectometers (FWDs) using methods such as suggested by AASHTO. In addition to pavement design, structural condition is a critical input for the selection of maintenance and rehabilitation strategies in pavement management system (PMS) application. However, use of SN in network level application has not been practical because of limitations of FWD such as stop-and-go operation, lane closures, and low testing frequency. The traffic speed deflectometer (TSD), a continuous deflection device, has recently been gaining worldwide application as a reliable NDT device for network level PMS applications. The objective of this study is to develop a practical approach to compute and utilize SN of in-service flexible pavements from TSD data for network level PMS applications. The study is based on the fundamental that, for the same pavement, SNeff from the TSD using the proposed method should be in good agreement with SNeff from the FWD using AASHTO method. The developed method was field validated with TSD and FWD data collected at in-service pavement sections. In addition, the use of structural number ratio, defined as a ratio of SNeff to required SN, in network level prioritization of structural capacity improvements was illustrated.
Effects of Compaction Moisture Content on Permanent Deformation of Soils Subjected to Repeated Triaxial Load Tests
Authors: de Lima Caroline Dias Amancio , da Motta Laura Maria Goretti , Aragão Francisco Thiago Sacramento
Published: January 2019

Water content is one of the key parameters that can cause variations in the elastic and plastic deformation of pavement layers. More specifically, both the compaction moisture and the post-compaction moisture should be carefully controlled. The objective of this study is to analyze the effects of compaction moisture on the accumulation of permanent deformation when unbound materials are subjected to repeated triaxial loads. The moisture contents were defined according to the compaction curve of each soil, being one above and one below the optimum moisture content which has been typically considered for the design of asphalt pavements in Brazil. The four soils evaluated in the study are commonly used in flexible pavements and have different classifications according to the Brazilian Miniature, Compacted, Tropical (MCT) methodology tailored to classify tropical soils. Specimens were subjected to permanent deformation tests and the results obtained show that the moisture content can significantly affect the mechanical behavior of soils. That effect is significant on both sides of the compaction curve, but the permanent deformation increases as the compaction moisture content increases on the wet side. This work is part of a broader and comprehensive research project in progress in Brazil to continuously update the current version of the Brazilian mechanistic-empirical pavement design guide. The proper understanding and characterization of the resistance to permanent deformation of unbound materials is a key part of that design guide.
The positive influence of psychological intervention on the level of anxiety and depression in dialysis patients: A pilot study
Authors: Bargiel-Matusiewicz Kamilla , Łyś Agnieszka , Stelmachowska Paulina
Published: January 2019

Medical progress in dialysis therapy made it possible to treat patients with the end-stage renal disease for many years. But at the other side it may lead to profound changes in everyday life and may induce depression and anxiety. The research presented in this article explores the influence of psychological interventions on anxiety and depression levels in patients undergoing dialysis therapy. The experimental design included two experimental groups: cognitive intervention and cognitive/narrative intervention and one control group (standard treatment). In total, 139 participants aged 22–75, including 67 women and 72 men diagnosed with end-stage renal disease and treated with dialysis, were divided into a control group and two experimental groups. Two well-known tools were used in the study: Beck Depression Inventory and State-Trait Anxiety Inventory. It was indicated that cognitive intervention may decrease the level of anxiety as a state, whereas cognitive/narrative intervention may decrease the level of anxiety as a state and the level of depression in dialysis patients. The stronger effect in the case of using narrative therapy may be the consequence of the fact that narrative therapy stimulates deeper analysis of the discussed issues (involving emotional level).
Contracting and the Bureaucratic Representation of Minorities and Women: Examining Evidence From Federal Agencies
Authors: Brown Lawrence A. , Kellough J. Edward
Published: January 2019

This study examines the question of whether the extent of contracting out by U.S. federal agencies has an impact on the representation of minorities and women in those agencies. Contracting often results in reductions in force (RIF), which may occur at the lower and middle levels where there is significant representation of minorities and women. As a result, agencies that engage in higher levels of contracting may have lower levels of representation of minorities and women overall and in selected grade levels, controlling for other known determinants of minority and female representation. A panel design is employed with data on outside contracts as a proportion of each agency’s budget from 2009 to 2015. Those data are matched with a 1-year lag to data on the employment of African Americans, Hispanics, and women from 2010 to 2016. Findings indicate that contracting is associated with lower levels of African American, Hispanic, and female employment in selected grade levels.
Masculinity, Injury, and Death: Implications for Anti-Knife-Carrying Messages
Authors: Palasinski Marek , Brown William , Shortland Neil , Riggs Damien W. , Chen Minsi , Bowman-Grieve Lorraine
Published: January 2019

Although knives are the most common homicide instrument in Britain, factors that influence knife-carrying tolerance (i.e., the extent to which it is seen as acceptable and justified) and perceptions of anti-knife messages (i.e., slogans and posters aimed at reducing knife crime) have not been examined, which the current article will cover by featuring progressively related studies. In Study 1, 227 men took part in a study on factors associated with knife-carrying. In Study 2, 200 participants took part in an experimental study on anti-knife slogans. In Study 3, 169 men took part in a study on existing anti-knife injury posters. In Study 4, 151 men took part in a study on anti-knife CGI posters featuring an avatar with different types of knife injury. Study 1 proposes a structural equation model that shows the intercorrelations between physical defense ability, limited trust in authority, limited control over one’s status and the need for respect, and how they predict aggressive masculinity (i.e., macho culture), which, in turn, predicts knife-carrying tolerance. The model also reveals two significant latent factors: saving face inter-male competition (i.e., honor) and perceived social ecological constraints (i.e., socioeconomic limitations). Study 2 shows that the injury slogan was rated as most persuasive. Study 3 shows that the fresh injury poster was rated as most persuasive, emotional, and believable. Study 4 shows that it was the eye injury that was rated as most persuasive, emotional, and believable. The article supports protection motivation theory and offers practical insights into tackling knife crime.
A Longitudinal Study of the Bidirectional Relations Between Anxiety Symptoms and Peer Victimization in Urban Adolescents
Authors: Drazdowski Tess K. , Kliewer Wendy L. , Farrell Albert , Sullivan Terri , Roberson-Nay Roxann , Jäggi Lena
Published: January 2019

The current study examined bidirectional relations between anxious symptoms and two forms of peer victimization (i.e., overt and relational) within an underrepresented sample of urban adolescents during key transition periods (i.e., elementary to middle school; middle school to high school) and the following 2 years. A predominantly African American sample (91%) of 358 adolescents (56% female, mean age = 12.10 years) living in low-income urban areas were assessed annually across 4 years. Using self-report measures, adolescents reported on their past year experiences of anxiety and peer victimization. Longitudinal path analyses tested progressively complex models for each type of victimization. Anxious symptoms predicted both overt and relational victimization at the time of transition (Wave 1 to Wave 2) and the following year (Wave 2 to Wave 3). Furthermore, whereas previous levels of victimization and future anxious symptoms were positively correlated over time, only relational victimization at Wave 1 predicted anxious symptoms at Wave 2. Prior levels of each construct were the strongest predictor of future outcomes (e.g., anxious symptoms at Wave 1 predicting anxious symptoms at Wave 2). Overall, there was little support for bidirectional relations between anxiety symptoms and peer victimization. Intervention and prevention programs seeking to reduce peer victimization or anxiety should start by targeting the symptom/behavior of interest. Interventions that target anxious thoughts and feelings during these key transition times in adolescence should be assessed as areas of priority.
Walking the Walk: Testing a Theory-Derived Measure of Campus Sexual Assault Policy Implementation
Authors: Moylan Carrie A. , Hammock Amy C.
Published: January 2019

Institutional Theory posits that organizations sometimes engage in practices that are inconsistent with their stated policies—a process called “decoupling”—due to three types of legitimacy pressures: normative, coercive, and mimetic. Limited previous research suggests that such decoupling between policy and practice may be occurring in institutions of higher education (IHEs) when addressing sexual assault. The objective of this study was to test a measure designed to assess sexual assault policy implementation using the constructs of Institutional Theory. The measure was tested with a national sample of 210 staff and faculty at IHEs who work on sexual assault prevention and response on their campuses. This study assessed (a) the reliability of the measure; (b) the degree to which the measure identified legitimacy pressures and decoupling in the sample; (c) the degree to which legitimacy pressures were linked to decoupling in the sample, as the theory suggests; and (d) the degree to which campuses and individual characteristics were differentially associated with decoupling and legitimacy pressures. Principal factor analysis resulted in a factor structure that conformed reasonably well to the existing constructs of Institutional Theory, with the addition of a new construct reflecting an institution’s stated commitment to addressing sexual assault. Regression analyses found that only normative legitimacy pressures significantly predicted decoupling and commitment. Higher decoupling scores were found for public campuses and larger institutions. Campus-based victim advocates reported significantly higher rates of decoupling than Title IX coordinators. The findings suggest that the process of policy implementation may vary across campus types and that further research is needed to better understand the impact of campus sexual assault regulatory attention.
The empowerment of rural migrantlalas: Contending queerness and heteronormativity in China
Authors: Liu Tingting
Published: January 2019

In today’s China, women’s social roles continue to be rigidly associated with gender-based responsibilities that include defending the integrity of their family, entering into heteronormative marriage, and showing reproductive capabilities. Most of those who self-identify as lalas (lesbians) struggle with such issues as self-shaming emotions, disclosing their homosexuality to family members, friends, or colleagues, and dealing with family and social pressures. Within this context, I investigate queerness in a group of young Chinese rural migrant lalas working and living in the industrial area of the Pearl River Delta economic zone in South China. I draw two conclusions. First, rural-to-urban labour migration empowers rural female lalas by providing a measure of economic independence and an escape from patriarchal and homophobic family relations. Second, the integration of traditional (offline and face-to-face) socializing locations and emerging virtual communicative spaces plays an important role in the process through which possibilities of living a queer life are carved out.
A novel stability prediction method for milling operations using the holistic-interpolation scheme
Authors: Qin Chengjin , Tao Jianfeng , Liu Chengliang
Published: January 2019

Currently, accurate and efficient determination of chatter-free cutting conditions is becoming increasingly important. This paper proposes a semi-analytical stability prediction method for milling processes using the holistic-interpolation scheme. The dynamics considering regeneration effect for milling operations is formulated as delay differential equations with time-periodic coefficients. The period of milling dynamic system is divided into two time periods according to the value of the coefficient matrix. On each small time interval for the forced vibration time period, the holistic-interpolation method is utilized by approximating the state term, the delay term, and the time-periodic parameter matrix as a whole unit with the second-order Lagrange interpolating polynomials. Then the Floquet transition matrix can be semi-analytically constructed for milling stability prediction according to Floquet theory. Finally, the benchmark examples of milling models are utilized to validate the effectiveness of the proposed method, which shows that the proposed algorithm achieves both high computational accuracy and efficiency.
Flexural Testing of Composite Laminates for Drilling Trial Assessment
Authors: Farrow I.R. , Lee J. , Kong C.D.
Published: January 2019

This work presents a study of flexural testing as a convenient method for ranking drilling trials of composite materials. The work includes an experimental study of drilling parameter effects on composite laminate hole quality as measured by static tension, compression and flexural open hole tests. Flexural testing and results processed in terms of the outermost 0° layer provides a consistent ranking of holes drilled with different process parameters despite only subtle changes in static notched strength for the thick composite samples tested. Specific observations from flexural tests are consistent with current drilling practices in terms of best process parameter settings and the method shows sufficient sensitivity to distinguish between the effects of drill-entry and drill-exit damage and subtle changes in lay-up.
Prediction of the Compresion-After-Impact Strength of Thin-Skin Stiffened Composite Panels
Authors: Zhuk Y. , Soutis C. , Guz I.
Published: January 2019

The compressive response of thin-skin stiffened composite panels with low velocity impact damage is examined. The finite element method together with the Soutis-Fleck fracture mechanics model is used to predict damage initiation in the form of fibre microbuckling in the 0° plies, propagation and final failure; in the model the impact damage is replaced with an equivalent circular or elliptical open hole. Theoretical results are compared to experimental data and found in good agreement.
Low Energy Impact Performance of Interleaved Carbon Fibre Reinforced Epoxy Laminates
Authors: Yuan Q. , Karger-Kocsis J. , Ye L.
Published: January 2019

Cross-ply and quasi-isotropic carbon fibre reinforced epoxy (CF/EP) laminates were toughened by addition of interleaves, which consisted of either a modified epoxy resin or random PET mat embedded in a modified epoxy resin. Impact and multiple impact performances of the laminates were studied using an instrumented falling weight impact tester. A simple model was used to correlate the performance of the laminates under multiple impact.
Atmospheric Pressure Helium Plasma Treatment of Ultrahigh Modulus Polyethylene Fibres
Authors: Qiu Y. , Anantharamaiah N. , Xie S. , Vaidya N.P. , Zhang C.
Published: January 2019

UHMPE fibres were treated for 0, 1, and 2 min respectively by atmospheric pressure He plasma on a capacitivelycoupled device at a frequency of 7.5 kHz and He pressure of 3430 Pa. The 2-min He plasma treatment etched the surface of the fibre resulting in a 70% increase of fibre/epoxy interfacial shear strength over the control and 1 -min treated group.
Interlaminar Tensile Strength of Carbon Fibre-Epoxy – Specimen Size, Layup and Manufacturing Effects
Authors: Wisnom M. R. , Jones M. I. , Hill G. F. J.
Published: January 2019

Curved beam bending tests have been carried out to measure interlaminar tensile strength of HTA/913 carbon fibre-epoxy. Scaled tests on high quality unidirectional specimens showed a size effect with a 20% reduction in strength for a factor of 4 increase in specimen dimensions. Specimens with (0/±45) layup gave similar strengths to unidirectional ones. A reduction of at least 21% was found for specimens failing in areas where manufacturing quality was not so high.
A Special Single-Fibre Pull-Out Technique for Determining the Fiber/Cement Interfacial Bond Strength
Authors: Caceres J. M. , Netravali A. N.
Published: January 2019

The paper discusses a simple specimen geometry to obtain the fibre/cement interfacial shear strength (IFSS). The specimens are easy to prepare and easy to test. The technique gives reliable and reproducible results. IFSS results for five different fibres with cement were measured. Most IFSS values obtained are in the range of 0.15 to 1.5 MPa. Despite the simplicity of the technique presented in this study, the results are in agreement with those obtained by several other researchers using different techniques and specimen geometry.
Mechanical Behaviour of Nickel Aluminide Reinforced Alumina (AL2O3-NiAl) Composites
Authors: Davies I. J. , Pezzotti G. , Bellosi A. , Sciti D. , Guicciardi S.
Published: January 2019

The microstructure and mechanical properties of hot-pressed alumina (Al2O3) matrix composites containing 20, 35, or 50 vol% of nickel aluminide (NiAl) were investigated. The mean Al2O3 grain size was found to decrease from approximately 2.0 μm (monolithic Al2O3) to 1.0 μm for the composite containing 50 vol% NiAl. Composite flexural strength values were lower than both the monolithic Al2O3 and NiAl and attributed to the weakly bonded NiAl particles acting as flaw origins. In contrast to this, the fracture toughness increased with NiAl volume fraction to a maximum of 4.90 MPa·m1/2, thus confirming the toughening effect of NiAl addition on Al2O3 ceramics, with the slope of the rising R-curve for the composite being approximately 8 times that of monolithic Al2O3.
Tensile Properties of Polypropylene Filled with Nanoscale Calcium Carbonate Particles
Authors: Zhang Ming Qiu , Rong Min Zhi , Pan Shun Long , Friedrich Klaus
Published: January 2019

To bring the positive effect of nanoscale calcium carbonate into play, macromolecular chains were introduced onto the particles by irradiation grafting polymerisation so that the hydrophobicity of the particles was increased and the loosen agglomerates became stronger. Tensile testing results demonstrated that polypropylene composites incorporated with the grafted nano-CaCO3 particles exhibited improved stiffness, strength and toughness at low filler content when proper grafting polymers are introduced. Species of grafting polymers adhered to the nanoparticles is an important factor affecting the modification effect of the matrix polymer. Therefore, composites performance can be purposely tailored accordingly.
Wear Behaviour and Friction Property of SiCp/Al Composites at Elevated Wear Environment Temperature
Authors: Ahn JJ , Ochiai S.
Published: January 2019

The effects of sliding speed and wear environment temperature (hereafter denoted as temperature) on the wear behaviour and friction coefficient of SiC particle reinforced A16061 composites (SiCp/Al) were studied using wear and friction test of a ring on disc type, and difference of wear mechanism in terms of temperature was also examined by a microscopic observation of worn surfaces. Thin surface layer (TSL) formed on the worn surface during the experiment was enhanced with increase of temperature. However, such a TSL was cracked due to point contact between the counter material and coarse SiC particles (and/or SiC clusters) existing on the worn surface of the SiCp/Al. Contour of worn surfaces became rougher with increase of temperature and sliding speed. Wear mechanism of the AA6061 changed from abrasive wear into adhesive wear at 300°C while for the SiCp/Al, wear mechanism did not changed in the test conditions. That is, abrasive wear was maintained up to 300°C. Due to the presence of SiC particles, Friction coefficient of the SiCp/Al was larger than that of the AA6061 regardless of the temperature. However, scatter of friction coefficient against temperature was smaller in the SiCp/Al than in the AA6061. Furthermore, the weight loss, the difference of specimen weight before and after the experiment, under the severest test condition was less in the SiCp/Al than in the AA6061.
Two - Dimensional Finite Element Analysis of Composite Patch Repairs Using Shell Laminate Elements
Authors: Tsamasphyros George J , Kanderakis George N , Furnarakis Nikos K , Marioli-Riga Zaira P
Published: January 2019

A host of one and two-sided composite patch reinforcements of metallic structures with different patch thickness were considered, in order to compare two-dimensional finite element analysis using shell laminate elements with three-dimensional finite element analysis. In order to verify the accuracy of this approach a parametric study has been performed and the 2D results were compared to the outcome of the corresponding three-dimensional finite element analysis, which accuracy has been experimentally verified in previous works. It was found that for the case of two-sided reinforcement the results obtained by the two methods were in very good agreement. For the case of one-sided reinforcement some deviation of the results of two-dimensional analysis has been observed, which was due to the tendency of the structure for out-of-plane bending, resulting from the bonding of a reinforcing patch to only one face of the structure. According to the results of this parametric study and since most aircraft structures are constrained against local out-of-plane bending (e.g. aircraft skins through stringers) two-dimensional finite elements analysis using shell laminate elements is proposed as an accurate and easy to use analysis tool for the design of both one and two-sided composite patch repairs of relatively simple structures.
Interpenetrating Vinylester/Epoxy Resins Reinforced by Flax Fibre Mat
Authors: Szabo J. S. , Romhany G. , Czigany T. , Karger-Kocsis J.
Published: January 2019

Vinylester/epoxy (VE/EP) hybrid resins of interpenetrating network (IPN) structure were reinforced by needled flax fibre mat. The flax content of the composites was kept constant (20 wt%) whereas the VE/EP ratio varied (70/30, 50/50, and 30/70). The mechanical properties of the composites, produced by resin transfer moulding, were determined in tensile and flexural loading. The mechanical anisotropy detected was traced to the orientation of the flax fibres during carding. The higher was the VE content of the hybrid IPN resin the better the mechanical performance was.
Structural Design with Angle Ply Laminates – Why and How
Authors: Piggott M. R.
Published: January 2019

In this paper we show that angle ply laminates are eminently practical for critical applications such as aircraft wings. The design methodology developed in the paper is relatively simple. It also lends itself automated construction and will likely lead to organic structures, which mimic natural ones.
Buckling of Foam Stabilised Composite Beams Analytical Modelling and Experiments
Authors: Rivallant S. , Ferrero J.F. , Barrau J.J.
Published: January 2019

An analytical modelling of symmetrical wrinkling is proposed: from original assumptions on displacements within the core, and from an energy minimisation method, it is possible to predict critical loads and buckling modes better than traditional models do, and to distinguish the influence of each structure component. Compression tests were carried out on sandwich structures to validate the model. A FE analysis has been achieved in parallel: a fine modelling allows finding results close to experimental ones.
Hysteresis Modelling in Ferromagnetic Composites
Authors: Ktena A. , Fotiadis D. I. , Massalas C. V.
Published: January 2019

The class of models presented here, targeting the modelling of hysteresis processes in the magnetic and elastic properties of ferromagnetic composites, is based on the Preisach formalism. The 1D and 2D formulations are equipped with a set of five different local hysteresis operators, to address different hysteretic responses. The resulting algorithms are efficient enough to be used as core models in simulations or real-time control. The types of hysteretic responses discussed and modeled include the magnetization vs. magnetic field response, M(H), the deformation vs. temperature response, x(T), and the deformation vs. field response, λ(H), also known as magnetostriction.
Effects of Loop Density of Knitted Fabric Preform on the Tensile Properties of Composites
Authors: Zaixia Fan , Zhangyu  , Yanmo Chen , Hairu Long
Published: January 2019

The effects of the loop density of knitted fabric preform made from GF/PP commingled yarns on the tensile properties of the composites are investigated. Six groups of composite specimens made from preforms with different loop densities are studied. It has been found that the elastic modulus and tensile strength of the composites show an increase followed by a slight decrease as the increase of the loop density of the preform, while the failure strain just changes totally contrarily.