Path Model Research Articles

Learning about heart failure from the news on a college campus: The effects of health attitude, healthy lifestyle, and health efficacy

ABSTRACT Literature on how people learn from health news is limited. While heart-related diseases top the list of 10 leading causes of death and major health expenditures in the U.S. literature on how people learn about heart-related illness is scarce. As a result, this study aimed to examine how people learn about heart failure from a news article, drawing on Bandura’s social cognitive theory (SCT) as the theoretical framework. Health news learning, the dependent measure, was assessed by a one-group posttest only design on the comprehension and recall of information about heart failure from the news story. Health attitude, healthy lifestyle, and health efficacy were the independent measures. Three hundred and fifty-six students and staff from a college in the northeast of the United States participated in this study. It was found that whether people think their health is important (health attitude), healthy lifestyle choices, and health efficacy were significant predictors of health news learning. A path model was constructed, and health efficacy emerged as an important mediator of the path model. SCT was found to be a valuable conceptual framework in assessing health news learning. Limitations for the study were discussed.

Volitional processes in changing physical activity: A randomized controlled trial with individuals with knee osteoarthritis.

A health action process approach (HAPA)-based intervention was designed to support moderate-to-vigorous physical activity (MVPA) in individuals with osteoarthritis of the knee (OAK). In secondary analyses of the randomized controlled trial "preventing the impairment of primary osteoarthritis by high-impact long-term physical exercise regimen-psychological adherence program," we examined long-term effects of the intervention on HAPA determinants and MVPA, and explored the former as mediators of change. N = 241 individuals with OAK (63% women, aged 44-80 years) were randomly assigned to the 12-month intervention condition (IC) or active control condition (CC). Between 2016 and 2020, self-reported HAPA determinants (action and coping planning, maintenance and recovery self-efficacy, action control) and collaborative planning were assessed at 0, 6, 12, 18, and 24 months, accelerometer-assessed MVPA at 0, 12, and 24 months. Multilevel and manifest path models were fit. Compared to the CC, action planning was higher in the IC at 6, 12, and 24 months. Maintenance and recovery self-efficacy were stable in the IC but decreased in the CC. MVPA decreased in both conditions. More action planning in the IC at 12 months was related to higher MVPA at 24 months, but, as in all other models, the indirect effect was nonsignificant. The intervention partly stabilized or enhanced HAPA determinants but did not increase MVPA in a Western, highly-educated sample with OAK. Future work might use blended-care approaches enriched by mobile applications for continuous MVPA support. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The Effect of Occupancy and Environmental Physical Variables on Classrooms’ Natural Ventilation: A Path Modeling Approach

In this paper, we use a path model to study natural ventilation in classrooms and research the link between air change rate, occupancy, and both outdoor and indoor physical variables. In general, the path model is derived from the building physics and occupant behavioral considerations via structural equation modeling (SEM), and allows for the use of continuous observable and unobservable factors. The latter are often employed in behavioral and social sciences to represent personal and group attributes. The path model is validated with data gathered during two consecutive academic years from four classrooms of a Portuguese school. The results confirm indoor and outdoor air temperature as major drivers of classroom ventilation, with standardized total path coefficients of approximately 0.55. Solar energy, precipitation, and occupancy are also significant drivers of classroom ventilation, with standardized total path coefficients of 0.24, −0.18, and 0.17, respectively. These results contribute to our understanding of the relative importance of occupancy as well as to identifying the most relevant environmental determinants of natural classroom ventilation. In spite of the statistical significance of the path model as a whole and its detailed causal relationships (direct, indirect, and feedback), only 58% of classroom ventilation variance is explained by the selected input variables. Because naturally ventilated classrooms depend significantly on occupants’ interactions with the built environment, i.e., opening/closing windows and blinds, extending path modeling to include additional personal and context-related drivers of occupants’ behavior would allow for further insights into the complex multi-domain topic of natural classroom ventilation.

Examining the Impact of ict Use and Related Attitudes on Students’ Achievements in Science Using the pls-sem Model

Abstract Investigations were conducted into the relationships between science achievement and ict use in and out of the classroom, as well as the mediating effects of students’ interest in and perceptions of their ict proficiency. The primary focus of this study has been the association between ict and scientific achievement among Singaporean students as measured by the Programme for International Student Assessment (pisa) 2018. This study examined pisa 2018 data using partial least squares structural equation modeling (pls-sem) to evaluate the effect of ict use on students’ achievements in science. Complex cause-and-effect relationships in path models with latent variables can be estimated using the structural equation modeling method known as pls-sem. 6,676 15-year-old Singaporean students who participated in the 2018 Programme for International Student Assessment (pisa) were examined. Students’ interest in ict, their assessment of their ict competency, and their accomplishment in science were found to be correlated with how they used ict both inside and outside of the classroom. The findings also imply that the association between ict use and science accomplishment may be mediated by students’ perceived ict proficiency and interest. This research can contribute to advancing the theoretical knowledge of technology, learning, and the cultural environment, in addition to practical ict implementations in scientific classes that consider the variances in ict affects.

Early medical risks to language development in extremely preterm infants.

To study the mechanistic role of neonatal morbidities on language performance in extremely preterm (EP) infants. We conducted secondary analyses on EP infants born at a single tertiary care center, investigating whether neonatal morbidities mediated associations between gestational age and language performance at 18-26 months corrected age. Infants born at 25-26 weeks (n = 298) outperformed those born at 22-24 weeks (n = 177) in expressive communication, receptive communication, composite language, and cognition. Retinopathy of prematurity (ROP), grade 2/3 bronchopulmonary dysplasia (BPD), and cognition partially explained gestational age effects on expressive and receptive communication. In the final sequential path models, infants born 22-24 weeks gestation were more likely to be diagnosed with grade 2/3 BPD, which was linked to diminished cognitive skills, and reduced language skills. Families of EP infants born under 25 weeks or with ROP and/or grade 2/3 BPD should be counseled about higher language impairment risk and receive proactive intervention.

The Role of Guilt Feelings in the Development of the Burnout Process: The Influence on Psychosomatic Problems.

Burnout is a psychological consequence of prolonged work-related stress. Previous studies have concluded that guilt feelings could explain the development of the burnout process and its relationship with other health disorders. The aim of this study was to evaluate the mediating role of guilt feelings in the relationship between burnout and psychosomatic problems. The sample comprised 714 Brazilian teachers (82.10% women). Burnout was assessed using the Spanish Burnout Inventory (SBI). The hypotheses were evaluated together using a path model to test the mediating role of guilt feelings in the development of burnout and its relationship with psychosomatic problems. Two models were constructed: the hypothesized model (i.e., indolence → guilt → psychosomatic problems) vs. the alternative model (i.e., indolence → psychosomatic problems → guilt). According to the results, the hypothesized model obtained a satisfactory fit to the data, whereas the alternative model's fit was found to be inadequate. We concluded that the hypothesized model was a good representation of the relationship among burnout, guilt feelings and psychosomatic problems. We recommend taking into consideration feelings of guilt to improve the diagnosis of burnout.

Personality and interest in general practice: results from an online survey among medical students

BackgroundThe growing shortage of General Practitioners (GPs) is a Europe-wide challenge, particularly in rural areas. In Germany, the situation is worsened by an ageing workforce of GPs and insufficient training of new doctors. Many newly qualified physicians choose careers outside primary care or prefer to work part-time to balance work and family life. To address this problem, it is essential to understand the factors that influence medical students’ specialty choice, and then to take action to encourage them to specialise in General Practice (GP). In addition to medical school experiences, rural placements, or characteristics of the specialty, personality traits have been shown to influence students’ specialty decisions. A well-researched approach to assessing personality is the Five-Factor Model, which measures personality on the dimensions openness (to experience), conscientiousness, extraversion, agreeableness, and neuroticism. Using the findings about the links between students’ personalities and an increased interest in a career in General Practice may be an approach to raising the number of GPs.ObjectivesWe aimed to examine how students’ personality traits influence their interest in General Practice and their current intention to pursue General Practice as a specialty.MethodsIn March 2021, we started an ongoing online survey among medical students at the University of Würzburg and assessed cross-sectional data about the ‘Big Five’ personality traits and aspects of career choice. Until December 2022, we invited three cohorts of first-year beginners, and one cohort each of third-, fifth- and sixth-year students via email to participate in the survey. For statistical analysis, we performed linear regression and extended it into a path model to examine the relationship between students’ personality traits, their interest in General Practice, and whether they would currently choose General Practice for their future specialty. We controlled for possible confounding effects of age, gender, and current semester by using covariates.ResultsHigher levels of agreeableness and neuroticism predicted greater interest in GPs, whereas higher levels of conscientiousness and openness predicted less interest in GPs. The effects of extraversion were unclear. Age was a significant predictor of interest, with older age associated with greater interest in General Practice. Gender was not a significant predictor of interest in General Practice, and the results for semester were inconclusive. The interest in General Practice is a predictor of the intention to choose GP as a specialty. The personality dimensions show an indirect predictive effect on the intention to choose GP, mediated by interest in GP. In total, R² = 7.7% of the variance of the interest in GP was explained by the combination of personality dimensions and covariates.ConclusionOur study reveals that students’ personality traits predict their interest in General Practice and their intention to choose it as a specialty. Personality assessments can be integrated into counselling services to help students better understand their traits. Our findings highlight the great potential of considering personality in career counselling during medical education or even the extent of admission criteria to medical school by personality-related criteria.

Testing the Mediational Role of Classroom Interactions in the Dynamic Interplay Between Teacher Emotional Exhaustion and Children’s Disruptive Behavior

ABSTRACT Research Findings: Teacher emotional exhaustion and classroom-level disruptive child behaviors are prominent risk factors influencing teacher and child social-emotional and behavioral outcomes. Additionally, theoretical perspectives position links between teacher emotional exhaustion and children’s disruptive classroom behavior as influenced by other proximally occurring teacher-child interactive processes. The purpose of the study is twofold: 1) examine longitudinal bi-directional relationships between teachers’ emotional exhaustion and children’s disruptive classroom behaviors, and 2) examine teachers’ classroom interactions (i.e. emotional support, instructional support, and classroom organization) as mediators of this potentially longitudinal bi-directional relationship. A total of 756 preschool-aged children and 101 preschool teachers across 17 schools serving children from primarily low-income families within the southeastern United States were examined. Data were collected through a multiple-methods approach. Multi-level path models examined the bi-directional associations between teachers’ emotional exhaustion and classroom-level child disruptive behaviors and the mediating role of teacher-facilitated classroom interactions. No bi-directional or mediational links were found; however, teachers’ emotional exhaustion was linked to children’s disruptive classroom behavior, and classroom disruptive behaviors were linked with teachers’ emotional support and classroom organization. Practice or Policy: Facilitating support for teachers’ well-being is critical for school personnel to continue to promote children’s classroom behaviors and maintain effective classroom interactions.

Building pedestrian simulation and channel design simulation technology based on virtual reality technology

In recent years, virtual reality technology has been widely applied and researched in various fields. In digital architectural design and simulation, it has gradually become an important tool. For the evacuation of commercial buildings, virtual reality technology is introduced and a digital building evacuation simulation model based on panic emotions is proposed. Meanwhile, based on this model, the behavior and distribution of pedestrians are simulated, targeted evacuation design schemes are proposed, and the spatial evacuation congestion situation of each scheme is evaluated. These results confirm that in digital commercial building simulation design, the visibility loop rate of the strip path model is as high as 71.25%, which is 8.93% and 11.35% higher than that of the circular path and radiation path, respectively. Meanwhile, the reachability loop back rate of this model is as high as 76.39%. In addition, when the horizontal spacing is 2.5 m, the time for the group to complete evacuation is the shortest, only 180 seconds. And its evacuation rate reached a maximum of 0.4. When the horizontal spacing increases to 4.5 meters, the evacuation time and efficiency are close to the barrier free situation, and obstacles have little effect on reducing congestion. The adoption of the proposed method can help designers develop reasonable evacuation strategies more efficiently and safely, providing strong technical support for the field of architectural design.

Strategies for Regulating the Bioavailability and Mobility of Se and Cd in Cd-Contaminated Seleniferous Soils: Coupling the Bioavailable Se:Cd Molar Ratio with Soil Properties

The prevalent issue of cadmium (Cd) in naturally selenium (Se)-enriched soils has significantly impacted the safe utilization of Se-rich soils. Although Se antagonizes Cd and is affected by Se:Cd stoichiometry, the mechanism behind this interaction remains unclear. To reveal the relation between the soil bioavailable Se:Cd molar ratio (AMR-Se:Cd) and the transformation of Se and Cd fractions, as well as to identify the principal controlling factors, we conducted a study in Shanggao County, Yichun City, a naturally Se-rich area in Jiangxi Province, and quantitatively analyzed the distribution features of Se, Cd, and AMR-Se:Cd across different soil types and land use types. The results demonstrated that soil AMR-Se:Cd was statistically positively correlated with the bioavailable Se content (r = 0.331, p < 0.01) and had a negative correlation with the bioavailable Cd content (r = −0.402, p < 0.001). Cd was transformed from highly bioavailable fractions to less bioavailable fractions as the AMR-Se:Cd increased. A suitable AMR-Se:Cd was conducive to achieving a higher mobility of Se (mobility factor of 12.31%) and a lower mobility of Cd (mobility factor of 23.49%) simultaneously. Spearman correlation analysis and partial least squares path modeling revealed that soil type and land use type modulated the morphological transformation of soil Se and Cd by influencing changes in free Fe-Al oxides and soil organic matter content, which in turn altered the AMR-Se:Cd. Therefore, the findings of this study can offer guidance for regulating the appropriate AMR-Se:Cd in Se-rich soils through management practices to enhance the bioavailability and mobility of soil Se while diminishing the bioavailability and mobility of Cd.

Impact of global capabilities on performance in international logistics companies

PurposeIn order to make a difference in a globally competitive environment, companies should analyze their competitors, which is one of the factors around them, well, do research, observe the environment and know how to adapt. For this purpose, the research examines the effects of competitive intensity and marketing and sales capabilities, together with the global capabilities of logistics companies operating internationally (third-party logistics companies (3PL)), which are examined.Design/methodology/approachTo establish and test the model, a sample of 504 participants working at senior levels in internationally operating logistics companies (third-party logistics companies (3PL)) with their headquarters in Istanbul was taken and a scale consisting of a total of 32 statements was presented to them. Analyses were performed using Jamovi and SmartPLS 3.3.5. This program was used because, in addition to estimating path models with latent variables, it also calculated standard results evaluation criteria. First, the results of factor analysis are given. After these analyses were completed, the hypotheses were tested.FindingsThis research is supported by hypotheses as a result of the analysis that global capabilities are an important factor for logistics companies at the international level, and that the competitive intensity also affects the performance outputs and that marketing and sales capabilities also have an impact.Research limitations/implicationsSince data are collected from logistics companies operating globally, it is necessary to pay attention when the analysis results are compared with different sectors. Because the intensity of competition may vary depending on the sector and market in which companies operate. At the same time, the data were collected from authorized white-collar employees working at a senior level in logistics companies. Because, in terms of the level of being able to answer the questions about the variables examined in the research model, data were collected from high-level officials.Practical implicationsIt is getting harder and harder to compete on a global scale by going beyond national borders. The results of the analysis show how important the global capabilities of logistics companies are, especially the increasing importance of logistics activities for countries. For this reason, logistics companies operating on an international scale need to attach importance to the competitive intensity and develop their marketing and sales capabilities.Originality/valueThe research is original in that it examines the global capabilities of logistics companies in their international activities and the effects of competition intensity. In addition, it is important for companies in this sector to examine the effects of marketing and sales capabilities so that logistics companies can reach more customers in their international activities and be more effective in the market compared to their competitors.

Experiences of Acculturation Stress in First-Generation Immigrant Children: Examining the Relationship Among Acculturation Stress, Depression, and Family Dynamics

AbstractThroughout the years, immigration has been a significant movement in the USA and leads to the examination of acculturative stress. By employing the acculturation stress and vulnerability models, the present study aimed to examine the association among acculturation stress, self-esteem, depression, family cohesion, and familism in first-generation immigrant children. Longitudinal data from the Children of Immigrants Longitudinal Study (CILS) were used. The analytical sample (n = 5262) was predominantly female (51.1%) and between the ages of 12 and 18 (M = 14.23) years old. SPSS 27 and AMOS 27 were utilized to conduct a path analysis to examine the relationships among acculturation stress, self-esteem, depression, family cohesion, and familism. Our results showed good fit (χ2/df ratio = 11.49; CFI = 0.91; RMSEA = 0.05, CI [.04, .05]) for the full path model. Acculturation stress had a significant, negative association with depression (β = − 0.12, p < .001); a significant, negative association with self-esteem (β = − 0.12, p < .001); and a significant, positive association with family cohesion (β = 0.60, p < .01) and the familism index (β = 0.05, p < .05). Acculturation stress was found to be predictive of self-esteem, depression, and family cohesion for first-generation immigrant children between the ages of 12 and 18 years old. This study provides general implications for how mental health providers can understand the struggles and provide culturally competent therapeutic services for children and their families.

Biochar Influences Polyethylene Microplastic-Contaminated Soil Properties and Enzyme Activities

Microplastics (MPs) have emerged as a significant pollutant, threatening agricultural ecosystem sustainability and global food security. However, relatively few studies have investigated biochar remedial effects on plant growth and biochemical properties in soils contaminated with MPs. In polyethylene microplastic (PE-MP)-contaminated soil, we investigated corn stover biochar effects on soybean growth, soil nutrient content, enzyme activity, and microbial biomass and assessed its impact on soil microbial resource limitations. The addition of MPs inhibited soybean growth in various forms across four stages. Conversely, the addition of biochar to MPs improved soybean growth to some extent, where above-ground biomass increased by 5.82% after adding biochar to soils containing microplastics. In soil treated with MPs and biochar, nitrate nitrogen (N), available phosphorus (P), and available potassium (K) increased by 20.1, 27.4, and 57.2%, respectively, while available nitrogen significantly decreased to 128.3 mg kg−1 compared to the MP-only treatment. PE-MPs alone significantly reduced soil carbon (C), N, and P enzyme activities, as well as microbial biomass, with β-glucosidase, leucine aminopeptidase, and acid phosphatase activities decreasing by 29.9, 27.8, and 25.5%, respectively. Interestingly, biochar addition to MPs significantly alleviated these detrimental effects. Microbial biomass C, N, and P increased by up to 56.0, 22.5, and 96.6%, respectively, following biochar addition to soils containing MPs. Analysis of vector lengths, vector angles, and scatter plots indicated that the presence of MPs reduced soil N and P availability. Overall, while MPs inhibited soybean development, biochar addition alleviated this effect to some extent. Furthermore, partial least-squares path modeling revealed that MPs negatively affected soil chemical properties, microbial biomass, and enzyme activities, whereas biochar positively influenced soil enzyme activities.

Copula-based estimation of causal effects in multiple linear and path analysis models

Regression analysis is one of the most popularly used statistical technique which only measures the direct effect of independent variables on dependent variable. Path analysis looks for both direct and indirect effects of independent variables and may overcome several hurdles allied with regression models. It utilizes one or more structural regression equations in the model which are used to estimate the unknown parameters. The aim of this work is to study the path analysis models when the endogenous (dependent) variable and exogenous (independent) variables are linked through the elliptical copulas. Using well-organized numerical schemes, we investigate the performance of path models when direct and indirect effects are estimated applying classical ordinary least squares and copula-based regression approaches in different scenarios. Finally, three real data applications are also presented to demonstrate the performance of path analysis using copula approach.

Effects of social media engagement and romantic relationships on academic distraction with emotional attachment as a mediator

The current research attempts to unveil the moderating role of academic self-efficacy and the mediating role of emotional attachment between social media engagement, romantic relationships, and academic distraction. The path model analysis of the study indicates that academic distraction is positively related to social media engagement and romantic relationships as hypothesized in this study. Liking constitutes a significant mediating factor in both relations and is more so a heightener of the social media and romantic involvement distraction. Furthermore, the findings suggest that emotional attachment interacts with academic self-efficacy concerning academic distraction, with those students having greater self-efficacy reporting higher levels of distraction. These findings therefore point to the need for educational practices and student support systems, to attend to the role of emotional and relational factors particularly, emotional attachment to students’ academic focus. This way the dynamics will make educators and policymakers understand how to address the issues of social media and romantic relationships in academic environments well.

Accuracy and Precision of Earthquake Location Programs: Insights from a Synthetic Controlled Experiment

Abstract Earthquake location programs employ diverse approaches to address the challenges posed by incomplete knowledge and simplified representation of complex Earth structures. Assessing their reliability in location and uncertainty characterization remains challenging as benchmark datasets with known event locations are rare, and usually confined to particular sources, such as quarry blasts. This study evaluates eight earthquake location methods (GrowClust, HypoDD, Hypoinverse, HypoSVI, NonLinLoc, NonLinLoc_SSST, VELEST, and XCORLOC) through a controlled synthetic computational experiment on 1000 clustered earthquakes based on the setting of the 2019 Ridgecrest, California, earthquake sequence. We construct a travel-time dataset using the fast-marching method and a 3D velocity model extracted from the Community Velocity Model, supplemented with a von Karman perturbation to represent small-scale heterogeneity, and including elevation effects. Picking errors, phase availability, and outliers are introduced to mimic difficulties encountered in seismic network monitoring. We compare the location results from eight programs applied to the same travel-time dataset and 1D velocity structure against the ground-truth locations. For this aftershock sequence, our results reveal the superior accuracy and precision of differential time-based location methods compared to single-event location methods. The results validate the significance of compensating for deviations from assumed 1D velocity structure either by path or site correction modeling or by cancellation of unmodeled structure using differential arrival times. We also evaluate the uncertainty quantification of each program and find that most of the programs underestimate the errors.

Structural equation modelling of the critical barriers influencing the adoption of green building concepts and technologies in Ghana

Purpose In Ghana, the adoption and application of green building concepts and technologies have not been fully explored. The study aimed to look into the key barriers and how they affect this. Design/methodology/approach Purposive and snowball sampling techniques were used to select a total of 292 construction industry stakeholders in Ghana who provided information via a questionnaire survey used for the data collection. Exploratory factor analysis and Partial least squares structural equation modelling (PLS-SEM) were used for computing the data analyses. Findings According to the study findings, the top five most critical barriers to the uptake of green building concepts and technologies (GBCs and Ts) in Ghana are: lack of government incentives/supports for implementing green building technologies (GBTs), lack of knowledge and awareness of GBTs and their benefits, lack of GBTs databases and information, Lack of green building (GB) expertise/skilled labour and Higher costs of GBTs. Principal Component Factor Analysis was used to further analyse the data, which allowed for the reduction of the 27 (27) factors to just four (4) underlying critical barriers: (1) government and knowledge-associated barriers, (2) technical barriers, (3) cost and finance barriers and (4) stakeholders’ attitude barriers. PLS-SEM techniques were used to analyse this collection of barriers, and the results showed that stakeholders’ attitude-associated barriers and cost and finance-related barriers have a significant negative influence on the uptake of GBCs and Ts in Ghana. This study’s findings have provided empirical evidence of the critical barriers to the uptake of GBCs and Ts from all stakeholders. Stakeholders desirous of implementing GBCs and Ts would work against the negative influences on the uptake of GBCs and TS. Originality/value Although there has been an abundance of research to examine the critical barriers to GB, however, the uniqueness of this study is nested in modelling the influence of the barriers on the adoption of GBCs and Ts using the PLS-SEM path modelling.

Enhancing Employee Outcomes Through Common Good Human Resource Management: Exploring the Role of Meaningfulness and Thriving

ABSTRACTIn the evolving landscape of human resource management (HRM), common good HRM (CG‐HRM) practices are increasingly recognized for their potential to align organizational goals with societal sustainability. Despite their importance, how CG‐HRM influences employee outcomes remain underexplored. Drawing on Conversation of Resources (COR) theory, this research explores the impact of CG‐HRM practices, conceptualized as critical organizational‐level resources, on employees' perception of meaningfulness of work. This perception significantly affects employee thriving, which in turn fosters innovative behavior. Employing a multi‐wave, multisource survey design, we collected data from 45 firms in China, involving 82 executives and 206 employees, to test our conceptual model. The findings from a multilevel path model reveal that organizational CG‐HRM practices contribute to employees' perceived meaningfulness of work, which promotes employee thriving and subsequently innovative behavior at the organizational level, while meaningfulness also contributes to thriving and, thus, innovative behavior at the employee level. Our research enriches the COR theory and contributes to the HRM, thriving, and innovation literature, offering insights for future research and practical implications for organizations striving to align their goals with societal and environmental sustainability while nurturing a thriving workforce.

Model-free active noise control using second-order simultaneous perturbation stochastic approximation algorithm for periodic noise

Model-free active noise control (ANC) using simultaneous perturbation stochastic approximation (SPSA) algorithm has recently attracted interest of researchers since it avoids the problem of secondary path modeling (SPM). However, the existing SPSA-based ANC methods are all based on the first-order SPSA algorithm and the convergence rate of these methods are significantly lower than that of the Filtered-x least mean square (FxLMS) algorithm. In order to enhance the convergence performance, this paper introduces the second-order SPSA algorithm into the ANC system. During the implementation of the second-order SPSA algorithm, a novel method of matrix positive definite transformation based on eigenvalue decomposition (EVD) is proposed. Convergence performance and tracking performance of ANC using the second-order SPSA algorithm are compared with ANC using the FxLMS algorithm and the standard SPSA through simulation and experimental verification. Simulation and experimental verification results show that ANC using the second-order SPSA algorithm can not only achieve the convergence rate comparable to that of ANC using the FxLMS algorithm, but also track the secondary path change.

Brain metabolic resilience in Alzheimer's disease: A predictor of cognitive decline and conversion to dementia

BackgroundBrain atrophy measured by structural imaging has been used to quantify resilience against neurodegeneration in Alzheimer's disease. Considering glucose hypometabolism is another marker of neurodegeneration, we quantified metabolic resilience (MR) based on Fluorodeoxyglucose positron emission tomography (FDG PET) and investigated its clinical implications. MethodsWe quantified the MR and other resilience metrics, including brain resilience (BR) and cognitive resilience (CR), using partial least squares path modeling from the ADNI database. A linear mixed-effects model and a Cox proportional hazards model were used to identify the impact of each resilience on longitudinal cognitive function and conversion to dementia, respectively. ResultsA total of 848 participants were included in this study. All resilience metrics (CR, BR, and MR) were associated with slower cognitive decline. Results from the ANOVA test, AIC and BIC values showed that the additional inclusion of MR improved the performances of the linear mixed effect models. In survival analysis, all resilience variables were negatively associated with the risk of conversion to dementia. In line with the results of the linear mixed effects models, the additional inclusion of MR into the models with different resilience variables increased the C-index. ConclusionRelative preservation of brain glucose metabolism is a valuable predictor of future cognitive decline and conversion to dementia, adding value to existing resilience metrics. While the utility of FDG PET in clinical settings is limited by cost and accessibility, it might have potential usefulness as a prognostic marker, especially in a context of resilience.