bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acute HIV Infection and CD4/CD8 Ratio Normalization After Antiretroviral Therapy Initiation
Authors: Davy-Mendez Thibaut , Napravnik Sonia , Zakharova Oksana , Kuruc JoAnn , Gay Cynthia , Hicks Charles B. , Mcgee Kara S. , Eron Joseph J. 
Published: August 2018

Background:
We estimated the effect of initiating virologically suppressive antiretroviral therapy (ART) during acute HIV infection versus chronic HIV infection (AHI vs. CHI) on CD4/CD8 ratio normalization.

Setting:
A prospective clinical cohort study.

Methods:
We included patients initiating ART with AHI and CHI between 2000 and 2015 and compared time from ART initiation to the first normal CD4/CD8 ratio (defined as CD4/CD8 ≥1) using Kaplan–Meier curves and multivariable Cox proportional hazards models. Patient time was censored at virologic failure, lost to follow-up, or death. We also characterized CD4, CD8, and CD4/CD8 trajectories over the first 3 years of ART.

Results:
The 1198 patients were 27% female and 60% African American, with a median age of 37 years (interquartile range 28–47) at ART initiation. The 83 AHI patients were more likely male, younger, and of white race, than CHI patients. After 2 years of suppressive ART, 70% of AHI patients achieved a normal CD4/CD8 ratio, compared to 6%–38% of CHI patients, with greater likelihood of normalization at higher baseline CD4 counts. Time to normalization was shortest among AHI patients, followed by CHI patients with higher baseline CD4. The adjusted hazard ratio for time to normalization for AHI patients compared to CHI patients with baseline CD4 >350 was 4.33 (95% CI: 3.16 to 5.93). Higher baseline CD4/CD8 ratio was also associated with time to normalization (adjusted hazard ratio 1.54; 1.46, 1.63, per 0.1 increase in ratio).

Conclusions:
Initiating ART during AHI at higher baseline CD4 cell counts and CD4/CD8 ratios was associated with shorter time to CD4/CD8 ratio normalization.
Trajectories of inflammatory biomarkers over the eighth decade and their associations with immune cell counts and epigenetic ageing
Authors: Stevenson Anna J , McCartney Daniel L , Harris Sarah E , Taylor Adele M , Redmond Paul , Starr John M , Zhang Qian , McRae Allan F , Wray Naomi R , Spires-Jones Tara L , McColl Barry W , McIntosh Andrew M , Deary Ian J , Marioni Riccardo E 
Published: August 2018

ABSTRACTBACKGROUNDEpigenetic age acceleration (an older methylation age compared to chronological age) correlates strongly with various age-related morbidities and mortality. Chronic systemic inflammation is thought to be a hallmark of ageing but the relationship between an increased epigenetic age and this likely key phenotype of ageing has not yet been extensively investigated.METHODSWe modelled the trajectories of the inflammatory biomarkers C-reactive protein (CRP; measured using both a high- and low-sensitivity assay), and interleukin-6 (IL-6) over the 8th decade in the Lothian Birth Cohort 1936. We additionally investigated the association between CRP and imputed leukocyte counts. Using linear mixed models we examined the cross-sectional and longitudinal association between the inflammatory biomarkers and two measures of epigenetic age acceleration, derived from the Horvath and Hannum epigenetic clocks.RESULTSLow-sensitivity CRP declined, high-sensitivity CRP did not change, and IL-6 increased over time. CRP levels inversely associated with total counts of CD8+T cells and CD4+T cells, and positively associated with senescent CD8+T cells, plasmablasts and granulocytes. Cross-sectionally, the Hannum, but not the Horvath, measure of age acceleration was positively associated with low-sensitivity CRP, high-sensitivity CRP, IL-6 and a restricted measure of CRP (≤10mg/L) likely reflecting levels relevant to chronic inflammation.CONCLUSIONSWe found a divergent relationship between inflammation and immune system parameters in older age. We additionally report the Hannum measure of epigenetic age acceleration associated with an elevated inflammatory profile cross-sectionally, but not longitudinally.
Glassy carbon, NIST Standard Reference Material (SRM 3600): hydrogen content, neutron vibrational density of states and heat capacity
Authors: Cappelletti Ronald L. , Udovic Terrence J. , Li Hui , Paul Rick L. 
Published: August 2018

Commercial glassy carbon plates being used as absolute intensity calibration standards in small-angle X-ray scattering applications (NIST SRM 3600) have been characterized in several recent publications. This contribution adds to the characterization by measuring the hydrogen content of a plate to be (4.8 ± 0.2) × 10−4 (mol H)/(mol C), and by measuring the vibrational spectrum by neutron inelastic scattering. The spectrum bears a strong resemblance to published measurements on graphite, allowing the identification of several spectral features. The measured spectrum is used to calculate the heat capacity of low-hydrogen-content glassy carbon for comparison with measurements reported here from 20 to 295 K.
Accelerating unstructured large eddy simulation solver with GPU
Authors: Liu Hongbin , Su Xinrong , Yuan Xin 
Published: August 2018

Purpose
Adopting large eddy simulation (LES) to simulate the complex flow in turbomachinery is appropriate to overcome the limitation of current Reynolds-Averaged Navier–Stokes modelling and it provides a deeper understanding of the complicated transitional and turbulent flow mechanism; however, the large computational cost limits its application in high Reynolds number flow. This study aims to develop a three-dimensional GPU-enabled parallel-unstructured solver to speed up the high-fidelity LES simulation.

Design/methodology/approach
Compared to the central processing units (CPUs), graphics processing units (GPUs) can provide higher computational speed. This work aims to develop a three-dimensional GPU-enabled parallel-unstructured solver to speed up the high-fidelity LES simulation. A set of low-dissipation schemes designed for unstructured mesh is implemented with compute unified device architecture programming model. Several key parameters affecting the performance of the GPU code are discussed and further speed-up can be obtained by analysing the underlying finite volume-based numerical scheme.

Findings
The results show that an acceleration ratio of approximately 84 (on a single GPU) for double precision algorithm can be achieved with this unstructured GPU code. The transitional flow inside a compressor is simulated and the computational efficiency has been improved greatly. The transition process is discussed and the role of K-H instability playing in the transition mechanism is verified.

Practical/implications
The speed-up gained from GPU-enabled solver reaches 84 compared to original code running on CPU and the vast speed-up enables the fast-turnaround high-fidelity LES simulation.

Originality/value
The GPU-enabled flow solver is implemented and optimized according to the feature of finite volume scheme. The solving time is reduced remarkably and the detail structures including vortices are captured.
Numerical investigation of the fluid lag during hydraulic fracturing
Authors: Chen Bin , Cen Song , Barron Andrew R. , Owen D.R.J. , Li Chenfeng 
Published: August 2018

Purpose
The purpose of this paper is to systematically investigate the fluid lag phenomena and its influence in the hydraulic fracturing process, including all stages of fluid-lag evolution, the transition between different stages and their coupling with dynamic fracture propagation under common conditions.

Design/methodology/approach
A plane 2D model is developed to simulate the complex evolution of fluid lag during the propagation of a hydraulic fracture driven by an impressible Newtonian fluid. Based on the finite element method, a fully implicit solution scheme is proposed to solve the strongly coupled rock deformation, fluid flow and fracture propagation. Using the proposed model, comprehensive parametric studies are performed to examine the evolution of fluid lag in various geological and operational conditions.

Findings
The numerical simulations predict that the lag ratio is around 5% or even lower at the beginning stage of hydraulic fracture under practical geological conditions. With the fracture propagation, the lag ratio keeps decreasing and can be ignored in the late stage of hydraulic fracturing for typical parameter combinations. On the numerical aspect, whether the fluid lag can be ignored depends not only on the lag ratio but also on the minimum mesh size used for fluid flow. In addition, an overall mixed-mode fracture propagation factor is proposed to describe the relationship between diverse parameters and fracture curvature.

Research limitations/implications
In this study, relatively simple physical models such as linear elasticity for solid, Newtonian model for fluid and linear elasticity fracture mechanics for fracture are used. The current model does not account for such effects like leak off, poroelasticity and softening of rock formations, which may also visibly affect the fluid lag depending on specific reservoir conditions.

Originality/value
This study helps to understand the effect of fluid lag during hydraulic fracturing processes and provides numerical experience in dealing with the fluid lag with finite element simulation.
The use and abuse of safety indicators in construction
Authors: Oswald David , Zhang Rita Peihua , Lingard Helen , Pirzadeh Payam , Le Tiendung 
Published: August 2018

Purpose
The purpose of this paper is to present a critical review of the use of safety performance indicators in the construction industry. The authors consider the strengths, limitations and managerial consequences associated with commonly used indicators.

Design/methodology/approach
The authors combine two separate data sets in this critical review. These include 32 semi-structured interviews with construction industry representatives involved in the collection and reporting of safety indicators, as well as a multi-level safety climate survey that was conducted at 12 construction sites across Australia.

Findings
The analysis provides new evidence that, in their current use, commonly used H&S indicators are subject to manipulation and misinterpretation. Their usefulness as tools to support safety management activities in construction projects and organisations needs to be understood in the context of their limitations. In particular, safety indicators do not reflect the full set of factors that affect workplace safety and there will always be disagreement about what should be counted and how.

Originality/value
As a result of the substantial shortcomings of safety indicators, great care needs to be taken when using them to determine or evaluate organisational safety policy and practices.
The trade integration and Pakistan’s export performance
Authors: Alam Shaista 
Published: August 2018

Purpose
The purpose of this study is to investigate the effect of trade integration on Pakistan’s export performance (value of exports, number of exporters and number of products per exporter) during 2003 to 2010.

Design/methodology/approach
Data from the World Bank Exporters Dynamics Database are analysed using fixed effect panel data techniques.

Findings
The results suggest that trade integration with South Asian Free Trade Area (SAFTA), China and Iran play remarkable role in improving export value by 73, 29 and 55 per cent, respectively. It is found that on average more than 140 and 339 exporters increase after integration with SAFTA and China, respectively, and during the study period, 1,605 and 606 exporters entered into SAFTA and Chinese market, respectively. Moreover, 182 and 146 additional exporters entered in Malaysian and Iranian export market after integration, which is 19 and 98 per cent, respectively, of initial year’s number of exporters. In addition, Malaysia and Mauritius show positive and considerable effect on diversification of product variety.

Originality/value
This is an original empirical research. The contributions of the paper are many fold: this paper is first to analyse the effect of Pakistan’s trade integration established during 2000s decade; pioneer contribution of this study is to use the number of exporters and number of products, as well as the value of exports to measure the export performance of Pakistan; and this study uses positive and negative discrepancies in export value data, number of HS6 products exported as a proxy of product diversification, share of industrial exports in total exports and share of textile exports in industrial exports.
Assessing health care quality in adolescent clinics, implications for quality improvement
Authors: Anaba Emmanuel Anongeba , Abuosi Aaron Asibi 
Published: August 2018

Purpose
Adolescents are more exposed to risky health behaviors. However, many adolescents do not seek health care due to the poor quality of care. The purpose of this paper is to assess health care quality in adolescent clinics in Tema, a suburb of Ghana.

Design/methodology/approach
Cross-sectional survey design was adopted to collect data from 365 adolescent respondents. Data were analyzed with the aid of Statistical Package for Social Science (version 20) using descriptive statistics and multiple linear regression.

Findings
The results demonstrate that adolescents perceived quality of care in adolescent clinics to be good. The significant predictors of adolescents’ overall perceptions of quality of care were provider competencies (β=0.311, p<0.01), adolescent’s health literacy (β=0.359, p<0.01), appropriate package of services (β=0.093, p<0.05), and equity and non-discrimination (β=0.162, p<0.01).

Research limitations/implications
The study was conducted in an urban setting. Therefore, the generalization of findings must be done with caution.

Originality/value
Adolescent health care quality in Ghana is below expectation. However, it has received little attention from researchers. This study provides empirical evidence for adolescent health care quality improvement in developing countries like Ghana.
When social media traumatizes teens
Authors: McHugh Bridget Christine , Wisniewski Pamela , Rosson Mary Beth , Carroll John M. 
Published: August 2018

Purpose
The purpose of this paper is to examine the extent to which negative online risk experiences (information breaches, explicit content exposure, cyberbullying and sexual solicitations) cause post-traumatic stress disorder (PTSD) symptoms in adolescents. The study also explores whether teens’ short-term coping responses serve to mitigate PTSD or, instead, act as a response to stress from online events.

Design/methodology/approach
The study utilized a web-based diary design over the course of two months. Data were analyzed using hierarchical linear modeling with repeated measures.

Findings
The study confirmed that explicit content exposure, cyberbullying and sexual solicitations (but not information breaches) evoke symptoms of PTSD. Analyses also indicated that teens engage in active and communicative coping after they experience post-traumatic stress, regardless of risk type or frequency.

Practical implications
The authors found that teens took active measures to cope with online risks soon after they felt threatened (within a week). Actively coping with stressful situations has been shown to enhance adolescent resilience and reduce long-term negative effects of risk exposure. If these early coping behaviors can be detected, social media platforms may be able to embed effective interventions to support healthy coping processes that can further protect teens against long-term harm from exposure to online risks.

Originality/value
This is the first study to examine situational PTSD symptoms related to four types of adolescent online risk exposure within the week exposure occurred. By applying two competing theoretical frameworks (the adolescent resilience framework and transactional theory of stress), the authors show empirical evidence that suggests short-term coping responses are likely a stress reaction to PTSD, not a protective factor against it.
Assessing timebanking use and coordination: implications for service exchange tools
Authors: Yuan Chien Wen , Hanrahan Benjamin V. , Carroll John M. 
Published: August 2018

PurposeTimebanking is a generalized, voluntary service exchange that promotes use of otherwise idle resources in a community and facilitates community building. Participants offer and request services through the mediation of the timebank software. In timebanking, giving help and accepting help are both contributions; contributions are recognized and quantified through exchange of time-based currency. The purpose of this paper is to explore how users perceive timebank offers and requests differently and how they influence actual use.Design/methodology/approachThis survey study, conducted in over 120 timebanks across the USA, examines users’ timebanking participation, adapting dimensions of Technology Acceptance Model (TAM).FindingsThe authors found that perceived ease of use in timebanking platforms was positively associated with positive attitudes toward both requests and offers, whereas perceived usefulness was negatively associated with positive attitudes toward requests and offers. The authors also found that having positive attitudes toward requests was important to elicit behavioral intention to make a request, but that positive attitudes toward offers did not affect behavioral intentions to make offers.Practical implicationsThe authors discussed these results and proposed design suggestions for future service exchange tools to address the issues the authors raised.Originality/valueThe study is among the first few studies that examine timebanking participation using large-scale survey data. The authors evaluate sociotechnical factors of timebanking participation through adapting dimensions of TAM.
Female students’ preparedness for a male-dominated workplace
Authors: Alves Sianne , English Jane 
Published: August 2018

Purpose
To provide relevant, appropriate education to the female student population, their perceptions as women and preparedness to work in male-dominated spaces, such as the construction workplace, is essential. The aim of this study, by the Professional Communication Studies and the HIV/AIDS Inclusivity and Change Unit, was to explore whether the students have been appropriately prepared.

Design/methodology/approach
A qualitative methodology comprising six semi-structured focus groups was conducted with student cohorts in 2016 and 2017. The focus groups were drawn from different courses in 2016 and 2017 and comprised a total of 17 female students between the ages of 20 and 23 years old. Themes were developed by using NVivo for “literal” (Mason, 1996, p. 56) coding prior to manually coding the data using an interpretive lens. Eight dominant themes emerged from the data, which are discussed in the findings.

Findings
Responses were that the students perceived that their gender is advantageous to their entering the profession, as there is legislative support but that the challenge remains that they need to prove their worth more than their male counterparts. The curriculum fails to prepare and/or sensitise students to respond to gender-based challenges, some of which they have already experienced during vacation work.

Research limitations/implications
The sample is drawn from one institution. Whilst the university has a diverse student body, it is not confirmed that the sample groups were reflective of the broad base of women employed in the construction field in South Africa.

Social implications
The findings were aligned with those from developed countries. Whilst some challenges specific to developing countries were cited, they were not considered to be insurmountable.

Originality/value
Gender research is an important topic for countries which, like South Africa, have legislated that employment of women in construction be increased but do not underscore gender in curriculum development of construction courses in universities.
Testing the productivity bias hypothesis in Middle East countries
Authors: Halicioglu Ferda , Ketenci Natalya 
Published: August 2018

Purpose
The purpose of this paper is to empirically test the validity of the productivity bias hypothesis (PBH) in 18 Middle East countries.

Design/methodology/approach
The paper employs autoregressive-distributed lag approach to cointegration approach and stability tests.

Findings
The empirical results suggest the existence of the PBH only in the case of Bahrain, Kuwait and Saudi Arabia.

Practical implications
Conclusions drawn from this research could be useful for the policy-makers of governments and practitioners in international trade organizations.

Originality/value
This study extends the existing literature by providing initial empirical time series evidence of the PBH for the entire Middle East countries.
The effect of the financial crisis on the dynamic relation between foreign exchange and stock returns
Authors: Ahmed Neveen 
Published: August 2018

PurposeThe purpose of this paper is to study the dynamic relationship between foreign exchange and stock returns. Specifically, the authors examine the impact of the 2008 financial crises on the relation between foreign exchange and stock returns in the MENA region.Design/methodology/approachThe authors examine the long-run relation between these two variables using VECM and the authors study the volatility behavior of these two variables using the Dynamic VECH–generalized autoregressive conditional heteroskedasticity (GARCH) model. The sample covers the MENA region over the period 2004–2015.FindingsThe results indicate a regime shift in three countries: Egypt, Tunisia and Morocco. In addition, the results assert asymmetric relation between stock returns and changes in exchange rates during pre-crisis and post-crisis periods. Modeling the volatility of the foreign exchange and stock return and their covariance using VECH–GARCH suggests that the persistence in volatility is more prominent in the crisis/post-crisis period as compared with the pre-crisis period. Finally, the authors also find more significant results for the persistence parameter in the covariance between stock return and foreign exchange in the crisis/post-crisis period as compared with the pre-crisis period.Originality/valueTo the best of the authors’ knowledge, the studies by Wong and Li (2010) and Caporaleet al.(2014) are the only two that have examined the interaction between stock prices and foreign exchange during the recent financial crisis of 2008. To the authors’ knowledge, none of the previous literature examined the impact of financial 2008 crisis on the relation between foreign exchange and stock prices in the MENA.