bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on Dynamic Characteristics of Residual Char of CFB Boiler Based on CPFD Method
Authors: Shen Xin , Jia Li , Wang Yanlin , Guo Baihe , Fan Haodong , Qiao Xiaolei , Zhang Man , Jin Yan
Published: November 2020

When the load of Circulating Fluidized Bed (CFB) boiler changes dynamically, the accumulation and consumption of residual char causes a large inertia and hysteresis in the boiler combustion system. Therefore, accurate estimation of the residual char in the boiler is of great significance to the control system and improve the combustion efficiency. Based on the Computational Particles Fluid Dynamics (CPFD) method, a numerical simulation of the variable load process of CFB boiler was carried out, and the dynamic changes of the residual char inventory were analyzed by combining the coal feed, ash discharge, and furnace calorific value. The results showed that after CFB boiler reached stable operation, the residual char fluctuated from 11,000 kg to 16,000 kg, accounting for about 3.7% of the total bed material, and the residual char was in a dynamic balance. During the load-up phase, the average residual char was 17,500 kg, and during the load-down phase, the average residual char was 15,000 kg. In the process of load dynamic change, reasonable residual char stock can ensure the boiler load from one steady state to another steady state rapid transition.
A Study of Cloth Seal Leakage Performance Based on Geometry and Pressure Load
Authors: Gorgun Erdem , Aksit Mahmut Faruk , Dogu Yahya
Published: November 2020

Metal cloth seals have been used increasingly in gas turbines due to their flexibility and superior leakage performance. Leakage performance of a metal cloth seal depends on operating conditions, slot and geometric dimensions. These parameters need to be investigated for the best leakage performance. In this study, pressure drop and critical geometric parameters of typical cloth seal form are investigated with an experimental setup. Slot depth, cloth width, sealing gap, shim thickness, surface roughness, pressure drop, offset and mismatch are selected parameters for the screening experiments. Sixteen experiments were conducted following a two-level Resolution IV fractional factorial experiment design for eight parameters. The results indicated that strong parameters for the leakage performance are pressure drop, cloth width, slot depth and offset. Leakage rate is increased with an increase in slot depth, gap, shim thickness, pressure drop and mismatch. During screening experiments, the experiment with minimum flow rate has 86% lower leakage rate than the experiment with maximum flow rate. For main experiments, a Box-Behnken experiment design is applied to analyze nonlinear effects of four strong parameters on the leakage rate. A closed-form equation is derived based on the data and presented in this study.
Prediction of Reformed Gas Composition for Diesel Engines with a Reformed EGR System Using an Artificial Neural Network
Authors: Park Jiwon , Cho Jungkeun , Choi Heewon , Park Jungsoo
Published: November 2020

Facing the reinforced emission regulations and moving toward a clean powertrain, hydrogen has become one of the alternative fuels for the internal combustion engine. In this study, the prediction methodology of hydrogen yield by on-board fuel reforming under a diesel engine is introduced. An engine dynamometer test was performed, resulting in reduced particulate matter (PM) and NOx emission with an on-board reformer. Based on test results, the reformed gas production rate from the on-board reformer was trained and predicted using an artificial neural network with a backpropagation process at various operating conditions. Additional test points were used to verify predicted results, and sensitivity analysis was performed to obtain dominant parameters. As a result, the temperature at the reformer outlet and oxygen concentration is the most dominant parameters to predict reformed gas owing to auto-thermal reforming driven by partial oxidation reforming process, dominantly.
Durability Assessment of Wooden Pellets in Relation with Vibrations Occurring in a Logistic Process of the Final Product
Authors: Kuranc Andrzej , Stoma Monika , Rydzak Leszek , Pilipiuk Monika
Published: November 2020

Vibrations occurring during road transport can vary in a wide spectrum and they can lead to losses in quality of transported materials. However, the vibrations are definitely different than the loads experienced by pellet samples in the tester used for durability tests according to the standard ISO 17831-1. pThe aim of the study was to evaluate the durability of wood biomass pellets available for sale in large-area stores, in terms of loads occurring in transport. The durability of the ellets was tested by subjecting them to vertical and horizontal vibrations similar to those occurring during local transport of this type of fuel for the needs of households. Durability tests were also carried out in accordance with ISO 17831-1. The results were analyzed statistically. Among other, it was found that the vibration time impact on the tested pellet durability was significantly lower in case of horizontal vibrations than in vertical. Moreover, pellets with a diameter of 8 mm showed lower durability than pellets with a diameter of 6 mm. Durability tests carried out in accordance with ISO 17831-1 showed lower pellet strength results compared to the test methods based on lateral and vertical vibrations.
A Methodology for the Calculation of Typical Gas Concentration Values and Sampling Intervals in the Power Transformers of a Distribution System Operator
Authors: Bustamante Sergio , Manana Mario , Arroyo Alberto , Martinez Raquel , Laso Alberto
Published: November 2020

Predictive maintenance strategies in power transformers aim to assess the risk through the calculation and monitoring of the health index of the power transformers. The parameter most used in predictive maintenance and to calculate the health index of power transformers is the dissolved gas analysis (DGA). The current tendency is the use of online DGA monitoring equipment while continuing to perform analyses in the laboratory. Although the DGA is well known, there is a lack of published experimental data beyond that in the guides. This study used the nearest-rank method for obtaining the typical gas concentration values and the typical rates of gas increase from a transformer population to establish the optimal sampling interval and alarm thresholds of the continuous monitoring devices for each power transformer. The percentiles calculated by the nearest-rank method were within the ranges of the percentiles obtained using the R software, so this simple method was validated for this study. The results obtained show that the calculated concentration limits are within the range of or very close to those proposed in IEEE C57.104-2019 and IEC 60599:2015. The sampling intervals calculated for each transformer were not correct in all cases since the trend of the historical DGA samples modified the severity of the calculated intervals.
Thermo-Mechanical Stress Comparison of a GaN and SiC MOSFET for Photovoltaic Applications
Authors: Van De Sande Wieland , Alavi Omid , Nivelle Philippe , D’Haen Jan , Daenen Michaël
Published: November 2020

Integrating photovoltaic applications within urban environments creates the need for more compact and efficient power electronics that can guarantee long lifetimes. The upcoming wide-bandgap semiconductor devices show great promise in providing the first two properties, but their packaging requires further testing in order to optimize their reliability. This paper demonstrates one iteration of the design for reliability methodology used in order to compare the generated thermo-mechanical stress in the die attach and the bond wires of a GaN and SiC MOSFET. An electro-thermal model of a photovoltaic string inverter is used in order to translate a cloudy and a clear one-hour mission profile from Arizona into a junction losses profile. Subsequently, the finite element method models of both devices are constructed through reverse engineering in order to analyze the plastic energy. The results show that the plastic energy in the die attach caused by a cloudy mission-profile is much higher than that caused by a clear mission-profile. The GaN MOSFET, in spite of its reduced losses, endures around 5 times more plastic energy dissipation density in its die attach than the SiC MOSFET while the reverse is true for the bond wires. Potential design adaptations for both devices have been suggested to initiate a new iteration in the design for reliability methodology, which will ultimately lead to a more reliable design.
The Challenges and Opportunities of Renewable Energy Source (RES) Penetration in Indonesia: Case Study of Java-Bali Power System
Authors: Tambunan Handrea Bernando , Hakam Dzikri Firmansyah , Prahastono Iswan , Pharmatrisanti Anita , Purnomoadi Andreas Putro , Aisyah Siti , Wicaksono Yonny , Sandy I Gede Ryan
Published: November 2020

Nowadays, the integration of renewable energy sources, especially grid-connected photovoltaic, into electrical power systems, is increasing dramatically. There are several stimulants especially in the Java-Bali power system, including huge solar potential, a national renewable energy (RE) target, regulation support for prosumers, photovoltaic technology development, and multi-year power system planning. However, significant annual photovoltaic penetration can lead to critical issues, including a drop of netload during the day, ramping capability, and minimal load operation for thermal power plants. This study analyses the duck curve phenomenon in the Java-Bali power system that considers high shares of the baseload power plant and specific scenarios in photovoltaic (PV) penetration and electricity demand growth. This study also analyses future netload, need for fast ramping rate capability, and oversupply issues in the Java-Bali power system. The results showed that the duck curve phenomenon appears with a significant netload drop in the middle of the day because of high power generation from grid-connected PV. Furthermore, the need for fast ramp rate capability is critical for a higher peak load combined with the lowest netload valley. Moreover, the significant load growth with high grid-connected PV penetration level caused unit commitment issues for thermal power plants as baseload operators.
Effect of Phase Change Material Storage on the Dynamic Performance of a Direct Vapor Generation Solar Organic Rankine Cycle System
Authors: Alvi Jahan Zeb , Feng Yongqiang , Wang Qian , Imran Muhammad , Khan Lehar Asip , Pei Gang
Published: November 2020

Solar energy is a potential source for a thermal power generation system. A direct vapor generation solar organic Rankine cycle system using phase change material storage was analyzed in the present study. The overall system consisted of an arrangement of evacuated flat plate collectors, a phase-change-material-based thermal storage tank, a turbine, a water-cooled condenser, and an organic fluid pump. The MATLAB programming environment was used to develop the thermodynamic model of the whole system. The thermal storage tank was modeled using the finite difference method and the results were validated against experimental work carried out in the past. The hourly weather data of Karachi, Pakistan, was used to carry out the dynamic simulation of the system on a weekly, monthly, and annual basis. The impact of phase change material storage on the enhancement of the overall system performance during the charging and discharging modes was also evaluated. The annual organic Rankine cycle efficiency, system efficiency, and net power output were observed to be 12.16%, 9.38%, and 26.8 kW, respectively. The spring and autumn seasons showed better performance of the phase change material storage system compared to the summer and winter seasons. The rise in working fluid temperature, the fall in phase change material temperature, and the amount of heat stored by the thermal storage were found to be at a maximum in September, while their values became a minimum in February.
One-Dimensional Heterogeneous Reaction Model of a Drop-Tube Carbonator Reactor for Thermochemical Energy Storage Applications
Authors: Karasavvas Evgenios , Scaltsoyiannes Athanasios , Antzaras Andy , Fotiadis Kyriakos , Panopoulos Kyriakos , Lemonidou Angeliki , Voutetakis Spyros , Papadopoulou Simira
Published: November 2020

Calcium looping systems constitute a promising candidate for thermochemical energy storage (TCES) applications, as evidenced by the constantly escalating scientific and industrial interest. However, the technologically feasible transition from the research scale towards industrial and highly competitive markets sets as a prerequisite the optimal design and operation of the process, especially corresponding reactors. The present study investigates for the first time the development of a detailed, one-dimensional mathematical model for the steady-state simulation of a novel drop-tube carbonator reactor as a core equipment unit in a concentrated solar power (CSP)-thermochemical energy storage integration plant. A validated kinetic mathematical model for a carbonation reaction (CaO(s) + CO2(g) → CaCO3(s)) focused on thermochemical energy storage conditions was developed and implemented for different material conditions. The fast gas–solid reaction kinetics conformed with the drop-tube reactor concept, as the latter is suitable for very fast reactions. Reaction kinetics were controlled by the reaction temperature. Varying state profiles were computed across the length of the reactor by using a mathematical model in which reactant conversions, the reaction rate, and the temperature and velocity of gas and solid phases provided crucial information on the carbonator’s performance, among other factors. Through process simulations, the model-based investigation approach revealed respective restrictions on a tailor-made reactor of 10 kWth, pointing out the necessity of detailed models as a provision for design and scale-up studies.
Systematic Review of Site-Selection Processes in Onshore and Offshore Wind Energy Research
Authors: Spyridonidou Sofia , Vagiona Dimitra G.
Published: November 2020

Wind energy has a leading role in achieving a low-carbon or completely carbon-free energy sector in the near future. Scientific research on the site-selection aspects of onshore and offshore wind farms is of great importance, contributing to sustainable, technically and economically viable, and socially acceptable wind energy projects. This systematic review provides direct analysis and assessment of existing site-selection procedures and addresses a gap in knowledge in the onshore and offshore wind energy research field, identifying trends in the thematic modules of site-selection issues. Important insights and useful trends are highlighted in: (1) site-selection methodologies; (2) the type, number, and exclusion limits of exclusion criteria; (3) the type, number, importance, priority, and suitability classes of assessment criteria; (4) studies’ geographic locations; (5) spatial planning scales; (6) wind resource analysis; (7) sensitivity analysis; (8) participatory planning approaches, groups, and contributions; (9) laws, regulations, and policies related to wind farm siting; (10) suitability index classifications (i.e., linguistic and numeric); and (11) micro-siting configuration of wind turbines. Identified insights and trends could motivate the conduction of updated site-selection analyses on onshore and offshore wind energy research, addressing the determined gaps and enhancing global siting implementations.
Sound Environments
Authors: Kang Jian
Published: November 2020

Sound environment is a vital part of our overall environment [...]
Reduced Lignin Decomposition and Enhanced Soil Organic Carbon Stability by Acid Rain: Evidence from 13C Isotope and 13C NMR Analyses
Authors: Wu Jianping , Deng Qi , Hui Dafeng , Xiong Xin , Zhang Huiling , Zhao Mengdi , Wang Xuan , Hu Minghui , Su Yongxian , Zhang Hongou , Chu Guowei , Zhang Deqiang
Published: November 2020

Due to the emissions of air pollutants, acid rain in southern China poses a great threat to terrestrial ecosystems. However, its influences on ecological processes such as litter decomposition and soil organic carbon (SOC) accumulation are still not clear. The aim of this study was to understand the potential mechanisms of carbon sequestration change in response to long-term acid rain in a subtropical forest. A field experiment with simulated acid rain (SAR) treatment was conducted in a monsoon evergreen broadleaf forest in southern China. Four levels of SAR treatment were implemented by irrigating the plots with water of different pH values (4.5 as a control, 4.0, 3.5, and 3.0). The results showed that the concentration of SOC and recalcitrant index for the SAR pH = 3.0 treatment were significantly higher compared to the control. Lignin fractions in litter residue layers were significantly increased, while soil microbial biomass carbon and soil ligninolytic enzyme activities were reduced under the SAR treatment. The concentration of SOC and recalcitrant index had positive relationships with the litter residue lignin fraction, but negative relationships with soil ligninolytic enzyme activity. These findings indicate that soil carbon accumulation could be enhanced with more stable lignin input under prolonged acid rain in forest ecosystems in southern China.
Combining Deforestation and Species Distribution Models to Improve Measures of Chimpanzee Conservation Impacts of REDD: A Case Study from Ntakata Mountains, Western Tanzania
Authors: Dickson Rebecca , Baker Marc , Bonnin Noémie , Shoch David , Rifkin Benjamin , Stewart Fiona A. , Piel Alex K.
Published: November 2020

Projects to reduce emissions from deforestation and degradation (REDD) are designed to reduce carbon emissions through avoided deforestation and degradation, and in many cases, to produce additional community and biodiversity conservation co-benefits. While these co-benefits can be significant, quantifying conservation impacts has been challenging, and most projects use simple species presence to demonstrate positive biodiversity impact. Some of the same tools applied in the quantification of climate mitigation benefits have relevance and potential application to estimating co-benefits for biodiversity conservation. In western Tanzania, most chimpanzees live outside of national park boundaries, and thus face threats from human activity, including competition for suitable habitat. Through a case study of the Ntakata Mountains REDD project in western Tanzania, we demonstrate a combined application of deforestation modelling with species distribution models to assess forest conservation benefits in terms of avoided carbon emissions and improved chimpanzee habitat. The application of such tools is a novel approach that we argue permits the better design of future REDD projects for biodiversity co-benefits. This approach also enables project developers to produce the more manageable, accurate and cost-effective monitoring, reporting and verification of project impacts that are critical to verification under carbon standards.
Genetic Spectrum of Syndromic and Non-Syndromic Hearing Loss in Pakistani Families
Authors: Doll Julia , Vona Barbara , Schnapp Linda , Rüschendorf Franz , Khan Imran , Khan Saadullah , Muhammad Noor , Alam Khan Sher , Nawaz Hamed , Khan Ajmal , Ahmad Naseer , Kolb Susanne M. , Kühlewein Laura , Labonne Jonathan D. J. , Layman Lawrence C. , Hofrichter Michaela A. H. , Röder Tabea , Dittrich Marcus , Müller Tobias , Graves Tyler D. , Kong Il-Keun , Nanda Indrajit , Kim Hyung-Goo , Haaf Thomas
Published: November 2020

The current molecular genetic diagnostic rates for hereditary hearing loss (HL) vary considerably according to the population background. Pakistan and other countries with high rates of consanguineous marriages have served as a unique resource for studying rare and novel forms of recessive HL. A combined exome sequencing, bioinformatics analysis, and gene mapping approach for 21 consanguineous Pakistani families revealed 13 pathogenic or likely pathogenic variants in the genes GJB2, MYO7A, FGF3, CDC14A, SLITRK6, CDH23, and MYO15A, with an overall resolve rate of 61.9%. GJB2 and MYO7A were the most frequently involved genes in this cohort. All the identified variants were either homozygous or compound heterozygous, with two of them not previously described in the literature (15.4%). Overall, seven missense variants (53.8%), three nonsense variants (23.1%), two frameshift variants (15.4%), and one splice-site variant (7.7%) were observed. Syndromic HL was identified in five (23.8%) of the 21 families studied. This study reflects the extreme genetic heterogeneity observed in HL and expands the spectrum of variants in deafness-associated genes.
Published Research on Burnout in Nursing in Spain in the Last Decade: Bibliometric Analysis
Authors: Barragán Martín Ana Belén , Molero Jurado María del Mar , Pérez-Fuentes María del Carmen , Simón Márquez María del Mar , Sisto Maria , Gázquez Linares José Jesús
Published: November 2020

Scientific production in the last decades has evidenced an increase in burnout syndrome in healthcare professionals. The objective of this bibliometric study was to analyze scientific productions on burnout in nurses in 2009–2019. A search was made on the Web of Science database on burnout in nursing. The variables evaluated were number of publications per year, productivity based on the journal and relationships between authors. Data were analyzed using Bibexcel software, and Pajek was used to visualize the co-authorship network map. A total of 1528 publications related to burnout in nurses were identified. The years with the most productivity were 2016 to 2017, when the publication rate increased noticeably over previous years. The Spanish journal with the most production on the subject was Atención Primaria. The co-authorship network analyzed illustrated collaboration patterns among the researchers. Scientific publications on the subject have increased in recent years due to problems in the healthcare system, which is in need of prevention and intervention programs for healthcare professionals.
High Visceral Fat Area Attenuated the Negative Association between High Body Mass Index and Sarcopenia in Community-Dwelling Older Chinese People
Authors: Li Cheng , Kang Bingxian , Zhang Ting , Gu Hongru , Man Qingqing , Song Pengkun , Liu Zhen , Chen Jingyi , Wang Xile , Xu Bin , Zhao Wenhua , Zhang Jian
Published: November 2020

The association between obesity and sarcopenia remains controversial. The present study was conducted to explore the associations among body mass index (BMI), visceral fat area (VFA), and sarcopenia in older people and analyze their potential mechanisms. This cross-sectional study included 861 community-dwelling older Chinese people from three regions of China. BMI, VFA, muscle mass, muscle strength, physical performance, body composition, and metabolic markers were measured. Muscle mass and muscle strength were positively correlated with BMI, but were negatively correlated with VFA. Simple overweight/obesity was negatively associated with sarcopenia (OR = 0.07, 95% CI = 0.03~0.18), and the OR value was lower than combined obesity (OR = 0.16, 95% CI = 0.09~0.28). Fat free mass and total body protein were positively associated with high BMI but negatively associated with high VFA. Furthermore, high VFA was adversely associated with some metabolic risk factors of sarcopenia. Combination of BMI and VFA increased diagnostic efficiency of low muscle mass and sarcopenia. In conclusion, high BMI was negatively associated with sarcopenia, while high VFA attenuated the negative association between high BMI and sarcopenia. The opposite association may partially be attributed to their different associations with body composition and metabolic risk factors of sarcopenia. Therefore, bedsides BMI, VFA and its interaction with BMI should be considered in sarcopenia prevention.
Standing Up from a Chair with an Asymmetrical Initial Foot Position Decreases Trunk and Masticatory Muscle Activities in Healthy Young Men
Authors: Bae Youngsook
Published: November 2020

This study aimed to identify the activation of lower extremity, trunk, and masticatory muscle and trunk kinematics of the initial foot position during the sit-to-stand (STS) movement. Sixteen young men participated in this cross-sectional pilot study and performed STS using both symmetrical and asymmetrical foot positions. Activation of the tibialis anterior (TA), gastrocnemius lateral head (GA), rectus femoris (RF), biceps femoris (BF), rectus abdominis, erector spinae (ES), sternocleidomastoid (SCM), upper trapezius (UT), temporalis (TE), and masseter muscles in the dominant side was determined. For trunk kinematics, head and trunk velocities, front-back (For-Back) and mediolateral (Med-Lat) weight translation rates, and trunk inclination were measured. GA, TA, BF, and RF activation significantly increased, whereas ES, SCM, UT, and TE activation significantly decreased when using the asymmetrical foot position. Head velocity, For-Back, Med-Lat, and trunk inclination were also significantly decreased. In conclusion, the asymmetrical foot position increases muscle activation in the lower extremities and decreases trunk inclination. In addition, ES, UT, and TE muscle activity decreases at the initial asymmetrical foot position.
Heterogeneous Trajectory Classes of Social Engagement and Sex Differences for Older Adults in China
Authors: Ye Linglong , Xiao Jian , Fang Ya
Published: November 2020

This study aimed to identify the heterogeneous trajectory classes of social engagement among older adults in China and examine sex differences to determine how sociodemographic characteristics and health status impact these trajectory classes. A sample of 8117 participants aged ≥65 years from the Chinese Longitudinal Healthy Longevity Survey was included. Growth mixture modeling was conducted to estimate the trajectory classes of social engagement. Logistic regression was adopted to analyze the associations between individual characteristics and trajectory classes. Three trajectory classes of social engagement were identified: the high-decline (35.3%), medium-decline (57.6%), and low-increase (7.1%). Men were less likely to be in the medium-decline and low-increase classes than women. Older men benefited from economic factors more than women. Education exhibited a stronger protective effect on the high-decline class for older women. High physical functioning might enable older adults with the lowest initial level of social engagement to make efforts to engage in social activities, which was stronger for older men than women. For both men and women, a proper cognitive state and positive emotions were in favor of social engagement. These findings are valuable for achieving sex equity in social engagement development for healthy and active aging.
Lack of Safe Drinking Water for Lake Chapala Basin Communities in Mexico Inhibits Progress toward Sustainable Development Goals 3 and 6
Authors: Smith Charlotte D. , Jackson Kaitlyn , Peters Hannah , Herrera Lima Susana
Published: November 2020

Background: Access to safe, affordable and accessible drinking water is a human right and foundational to the third and sixth World Health Organization’s Sustainable Development Goals (SDGs). Unsafe drinking water is a risk factor for chronic and enteric diseases. Both chronic kidney disease (CKD) and diarrheal disease are highly prevalent in the Lake Chapala basin, Jalisco, Mexico, suggesting disparities in factors leading to successful achievement of these two SDGs. Methods: This study aimed to assess progress towards SDG three and six in the Lake Chapala basin. Qualitative, quantitative, and geospatial data were collected between May and August of 2019 from three towns within the municipalities of Poncitlán and Chapala. Results: Ninety-nine households participated in this study. Water sampling analyses determined 81.18% of samples from water jugs (garrafones) and 70.05% of samples from tap water were contaminated with total coliform bacteria, often including E. coli. Additionally, 32% of garrafón samples and 61.9% of tap water samples had detectable levels of arsenic. Approximately 97.94% of respondents stated that they believe clean water is a human right, but 78.57% feel the Mexican government does not do enough to make this a reality. Conclusions: This mixed methods approach highlights water quality as a serious issue in communities around Lake Chapala, and demonstrates inadequate drinking water as a key hazard, potentially perpetuating the high disease burden of both CKD and enteric disease in the region.
Nonparametric Limits of Agreement in Method Comparison Studies: A Simulation Study on Extreme Quantile Estimation
Authors: Gerke Oke
Published: November 2020

Bland–Altman limits of agreement and the underlying plot are a well-established means in method comparison studies on quantitative outcomes. Normally distributed paired differences, a constant bias, and variance homogeneity across the measurement range are implicit assumptions to this end. Whenever these assumptions are not fully met and cannot be remedied by an appropriate transformation of the data or the application of a regression approach, the 2.5% and 97.5% quantiles of the differences have to be estimated nonparametrically. Earlier, a simple Sample Quantile (SQ) estimator (a weighted average of the observations closest to the target quantile), the Harrell–Davis estimator (HD), and estimators of the Sfakianakis–Verginis type (SV) outperformed 10 other quantile estimators in terms of mean coverage for the next observation in a simulation study, based on sample sizes between 30 and 150. Here, we investigate the variability of the coverage probability of these three and another three promising nonparametric quantile estimators with n=50(50)200,250(250)1000. The SQ estimator outperformed the HD and SV estimators for n=50 and was slightly better for n=100, whereas the SQ, HD, and SV estimators performed identically well for n≥150. The similarity of the boxplots for the SQ estimator across both distributions and sample sizes was striking.
Personal and Lifestyle Determinants of HIV Transmission Risk in Spanish University Students
Authors: Alcocer-Bruno Cristian , Ferrer-Cascales Rosario , Ruiz-Robledillo Nicolás , Sánchez-SanSegundo Miriam , Zaragoza-Martí Ana
Published: November 2020

The increase in human immunodeficiency virus (HIV) transmission cases poses a serious public health concern. Although several previous studies have been conducted with the aim of identifying the risk factors for HIV transmission, the number of cases has been increasing, especially in youth. The present study is aimed at the identification of personal and lifestyle determinants of HIV transmission risk in a sample of 335 Spanish university students selected by convenience sampling from a public university located in Alicante (Spain). Sociodemographic factors, lifestyles, and variables of HIV risk of transmission were evaluated. Group differences on risk of HIV transmission were evaluated between participants depending on their sociodemographic characteristics (age, sex, relationship status, employment status, economic status, and sexual orientation) and lifestyle (diet, physical exercise, smoking, alcohol consumption, and stress). Linear regression models were conducted in order to identify those personal and lifestyle variables related to HIV transmission risk. The obtained results indicate that, generally, being older, in a relationship, and employed were factors related to a high risk of HIV transmission. Regarding lifestyle, poor diet, lower intensity of physical exercise, higher alcohol intake, and smoking were fundamentally associated with a higher risk of HIV transmission, through lower use of condoms and higher frequency of risky sexual behaviors. Hence, participants who develop an unhealthy lifestyle exhibit twice the probability of being at a high risk of HIV transmission, especially regarding these previously indicated behaviors. The present study points out the relevance of sociodemographic characteristics and lifestyles of university students in their proneness to developing risky behaviors for HIV infection. Future studies should be developed with larger, randomized, and more representative samples, in order to obtain significant information for the development of effective preventive strategies oriented toward the increase in the adherence to healthy lifestyles and HIV prevention.
Acceptability and Barriers to Use of the ASMAN Provider-Facing Electronic Platform for Peripartum Care in Public Facilities in Madhya Pradesh and Rajasthan, India: A Qualitative Study Using the Technology Acceptance Model-3
Authors: Usmanova Gulnoza , Gresh Ashley , Cohen Megan A. , Kim Young-Mi , Srivastava Ashish , Joshi Chandra Shekhar , Bhatt Deepak Chandra , Haws Rachel , Wadhwa Rajni , Sridhar Pompy , Bahl Nupur , Gaikwad Pratibha , Anderson Jean
Published: November 2020

The evolving field of mobile health (mHealth) is revolutionizing collection, management, and quality of clinical data in health systems. Particularly in low- and middle-income countries (LMICs), mHealth approaches for clinical decision support and record-keeping offer numerous potential advantages over paper records and in-person training and supervision. We conducted a content analysis of qualitative in-depth interviews using the Technology Acceptance Model 3 (TAM-3) to explore perspectives of providers and health managers in Madhya Pradesh and Rajasthan, India who were using the ASMAN (Alliance for Saving Mothers and Newborns) platform, a package of mHealth technologies to support management during the peripartum period. Respondents uniformly found ASMAN easy to use and felt it improved quality of care, reduced referral rates, ensured timely referral when needed, and aided reporting requirements. The TAM-3 model captured many determinants of reported respondent use behavior, including shifting workflow and job performance. However, some barriers to ASMAN digital platform use were structural and reported more often in facilities where ASMAN use was less consistent; these affect long-term impact, sustainability, and scalability of ASMAN and similar mHealth interventions. The transitioning of the program to the government, ensuring availability of dedicated funds, human resource support, and training and integration with government health information systems will ensure the sustainability of ASMAN.
Does Upper Cervical Manual Therapy Provide Additional Benefit in Disability and Mobility over a Physiotherapy Primary Care Program for Chronic Cervicalgia? A Randomized Controlled Trial
Authors: González-Rueda Vanessa , Hidalgo-García César , Rodríguez-Sanz Jacobo , Bueno-Gracia Elena , Pérez-Bellmunt Albert , Rodríguez-Rubio Pere Ramón , López-de-Celis Carlos
Published: November 2020

Introduction: Neck pain is a condition with a high incidence in primary care. Patients with chronic neck pain often experience reduction in neck mobility. However, no study to date has investigated the effects of manual mobilization of the upper cervical spine in patients with chronic mechanical neck pain and restricted upper cervical rotation. Objective: To evaluate the effect of adding an upper cervical translatoric mobilization or an inhibitory suboccipital technique to a conventional physical therapy protocol in patients with chronic neck pain test on disability and cervical range of motion. Design: Randomized controlled trial. Methods: Seventy-eight patients with chronic neck pain and restricted upper cervical rotation were randomized in three groups: Upper cervical translatoric mobilization group, inhibitory suboccipital technique group, or control group. The neck disability index, active cervical mobility, and the flexion–rotation test were assessed at baseline (T0), after the treatment (T1), and at three-month follow-up (T2). Results: There were no statistically significant differences between groups in neck disability index. The upper cervical translatoric mobilization group showed a significant increase in the flexion–rotation test to the more restricted side at T1 (F = 5.992; p < 0.004) and T2 (F = 5.212; p < 0.007) compared to the control group. The inhibitory suboccipital technique group showed a significant increase in the flexion–rotation test to the less restricted side at T1 (F = 3.590; p < 0.027). All groups presented high percentages of negative flexion–rotation tests. (T1: 69.2% upper neck translator mobilization group; 38.5% suboccipital inhibition technique group, 19.2% control group; at T2: 80.8%; 46.2% and 26.9% respectively). No significant differences in the active cervical mobility were found between groups. Conclusion: Adding manual therapy to a conventional physical therapy protocol for the upper cervical spine increased the flexion–rotation test in the short- and mid-term in patients with chronic neck pain. No changes were found in the neck disability index and the global active cervical range of motion.
Usability Assessment of an Innovative Device in Infusion Therapy: A Mix-Method Approach Study
Authors: Parreira Pedro , Sousa Liliana B. , Marques Inês A. , Santos-Costa Paulo , Cortez Sara , Carneiro Filipa , Cruz Arménio , Salgueiro-Oliveira Anabela
Published: November 2020

Background: Flushing a venous access device is an important procedure to maintain their patency and prevent malfunctioning and complications. An innovative double-chamber syringe was developed, allowing for the assessment of catheter patency, drug delivery and final flush. This study aims to assess the usability of this new device, considering three development stages (concept, semi-functional prototype, functional prototype). Methods: An iterative methodology based on a mix-method design (qualitative and quantitative) enabled the assessment of the devices’ usability by their primary end-users. A usability questionnaire was developed and applied, along with focus groups and individual interviews to nurses. Results: The usability questionnaire integrated 42 items focused on four dimensions (usefulness; ease of use; ease of learning; satisfaction and intention to use). The initial psychometric findings indicate a good internal consistency and the conceptual relevance of the items. The scores seem to be sensitive to the usability evaluation of the medical devices in different stages of product development (with lower values on functional prototype evaluation), and related to nurses’ perceptions about functional and ergonomic characteristics. Conclusions: Quantitative and qualitative data provided a comprehensive overview of the double-chamber syringes’ usability from the nurses’ point of view, informing us of features that must be addressed.
Development of a Prediction Model to Identify Children at Risk of Future Developmental Delay at Age 4 in a Population-Based Setting
Authors: van Dokkum Nienke H. , Reijneveld Sijmen A. , Heymans Martijn W. , Bos Arend F. , de Kroon Marlou L. A.
Published: November 2020

Our aim was to develop a prediction model for infants from the general population, with easily obtainable predictors, that accurately predicts risk of future developmental delay at age 4 and then assess its performance. Longitudinal cohort data were used (N = 1983), including full-term and preterm children. Development at age 4 was assessed using the Ages and Stages Questionnaire. Candidate predictors included perinatal and parental factors as well as growth and developmental milestones during the first two years. We applied multiple logistic regression with backwards selection and internal validation, and we assessed calibration and discriminative performance (i.e., area under the curve (AUC)). The model was evaluated in terms of sensitivity and specificity at several cut-off values. The final model included sex, maternal educational level, pre-existing maternal obesity, several milestones (smiling, speaking 2–3 word sentences, standing) and weight for height z score at age 1. The fit was good, and the discriminative performance was high (AUC: 0.837). Sensitivity and specificity were 73% and 80% at a cut-off probability of 10%. Our model is promising for use as a prediction tool in community-based settings. It could aid to identify infants in early life (age 2) with increased risk of future developmental problems at age 4 that may benefit from early interventions.
Acceptability and Feasibility of a Nurse-Led, Community Health Worker Partnered Latent Tuberculosis Medication Adherence Model for Homeless Adults
Authors: Salem Benissa E. , Klansek Erin , Morisky Donald E. , Shin Sanghyuk S. , Yadav Kartik , Chang Alicia H. , Nyamathi Adeline M.
Published: November 2020

Homeless adults are at increased risk of latent tuberculosis infection (LTBI), which can lead to active tuberculosis (TB) disease. The purpose of this study was to assess acceptability and feasibility of a six-month, nurse-led, community health worker-partnered short-course treatment (3HP) LTBI adherence model for a high risk, LTBI positive, homeless population. Informed by our community advisory board (CAB) and community-based participatory research principles (CBPR), a qualitative study was undertaken and used focus group discussions to identify perspectives of homeless men and women who had undergone LTBI treatment (N = 11, Mage = 51.2, SD 8.60, range 35–60). Three themes formed, which were engaging and recruiting LTBI intervention participants, delivering an LTBI intervention, and retaining LTBI intervention participants. Within those themes, barriers (e.g., lack of LTBI treatment readiness, substance use, etc.), and facilitators (e.g., LTBI and TB health education, familiarity with homeless population, etc.) were discussed to facilitate program recruitment, program delivery and program retention. These findings provide a greater understanding of how to effectively utilize a nurse-led, Community Health Worker (CHW) intervention delivery method to not only improve 3HP LTBI medication adherence, but also decrease substance use, improve mental health, and decrease unstable housing among this vulnerable population at high risk for active tuberculosis.
Confronting Racism within the Canadian Healthcare System: Systemic Exclusion of First Nations from Quality and Consistent Care
Authors: Phillips-Beck Wanda , Eni Rachel , Lavoie Josée G. , Avery Kinew Kathi , Kyoon Achan Grace , Katz Alan
Published: November 2020

The study is on racism against First Nation peoples in the Canadian healthcare system. The study design incorporates principles of grounded theory, participant and Indigenous (decolonizing) research. Four questions are addressed: (1) What is the root cause of racism against First Nation peoples in the healthcare system? (2) What factors perpetuate racisms existence? (3) What are the impacts of racism on First Nation health? (4) What needs to be done to eradicate racism and to create an equitable healthcare system that sufficiently represents the needs, interests and values of First Nation peoples?
Long-Term Effect of Income Level on Mortality after Stroke: A Nationwide Cohort Study in South Korea
Authors: Jeong Seungmin , Cho Sung-il , Kong So Yeon
Published: November 2020

We investigated whether income level has long-term effects on mortality rate in stroke patients and whether this varies with time after the first stroke event, using the National Health Insurance Service National Sample Cohort data from 2002 to 2015 in South Korea. The study population was new-onset stroke patients ≥18 years of age. Patients were categorized into Category (1) insured employees and Category (2) insured self-employed/Medical Aid beneficiaries. Each category was divided into three and four income level groups, retrospectively. The study population comprised of 11,668 patients. Among the Category 1 patients (n = 7720), the low-income group’s post-stroke mortality was 1.15-fold higher than the high-income group. Among the Category 2 patients (n = 3948), the lower income groups had higher post-stroke mortality than the high-income group (middle-income, aOR (adjusted odds ratio) 1.29; low-income, aOR 1.70; Medical Aid beneficiaries, aOR 2.19). In this category, the lower income groups’ post-stroke mortality risks compared to the high-income group were highest at 13–36 months after the first stroke event(middle-income, aOR 1.52; low-income, aOR 2.31; Medical Aid beneficiaries, aOR 2.53). Medical Aid beneficiaries had a significantly higher post-stroke mortality risk than the high-income group at all time points.
Let’s Live Healthier: The Relationship between Suicidal Behavior and Physical Activity in an Age-, Gender-, and Body Mass Index-Matched Adults
Authors: Park Jeong-Hui , Seo Myong-Won , Jung Hyun Chul , Lee Jung-Min
Published: November 2020

The purpose of this study was to identify the association between physical activity (PA) and predictors of suicidal behaviors and to investigate whether the different PA measurements influence the association between PA and suicidal behaviors in South Korean adults. This study analyzed data from the National Health and Nutrition Examination Survey 2014–2015 data. The study selected participants who checked suicide-related questions as “Yes” (n = 99) and checked suicide-related questions as “No” (n = 99) in the questionnaire. The age, gender, and body mass index of participants between the two groups were matched. The moderate to vigorous PA (p = 0.000) and sedentary PA (p = 0.000), measured by accelerometers, were a significant risk factor for suicidal behaviors. Furthermore, the number of steps was a considerable difference between the two groups (healthy group: 61,495.76 steps; suicide group: 40,517.34 steps), and the accelerometer and questionnaire also showed significant differences. The study demonstrated that there were significant associations with physical activity and socioeconomic status and suicidal behaviors in anthropometry (i.e., age, gender, height, weight) matched groups. Additionally, this study highlights the importance of the assessment of PAs, and increasing PA levels could reduce the incidence of suicidal behaviors.
Structure, Intensity and Player Duels in Under-13 Football Training in Switzerland
Authors: Uebersax Jonas , Roth Ralf , Bächle Tobias , Faude Oliver
Published: November 2020

We evaluated the structure (i.e., the different training parts), contents (i.e., the various activities used), intensity and occurrence of contact situations and headers during training sessions in under-13 football in Switzerland. A total of 242 players from 20 different teams on average aged 11.4 (SD 0.7) years participated. The participants were filmed during a typical training session while they were equipped with a heart rate sensor. The sessions were systematically recorded to allow for detailed analyses. Furthermore, a preliminary and explorative analysis of the influence of the level of play on these results was conducted. The overall findings indicated that training included 33.4% playing forms, 29.5% training forms, 28.4% inactivity time and 8.7% athletics. The highest heart rates were achieved in the playing forms (166 min−1, 83% HRmax) compared to the other two activities (training forms 154 min−1, 77% HRmax; athletics 150 min−1, 75% HRmax). Each player had 12.8 duels and 0.6 headers per training. Overall, most duels were conducted from the anterior direction. Playing forms induce higher cardio-circulatory load as well as a better learning environment. Potentially dangerous situations like contact with other players or headers occurred in a single player on average every six min during a training session.