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The characteristics of participatory institutions can be articulated in three main dimensions: input, process and output. The common assumption is that a dependency relationship exists, with process serving as a mediator between input and output. This paper puts the model to a rare empirical test drawing on a unique dataset of 70 Spanish advisory councils. Through a combination of exploratory factor and path analyses, we analyse the dimensionality of input, process and output and investigate the direct and indirect impact of inputs on process and outputs. Our analysis provides evidence that input factors have a direct impact on the output factor transparency, but their impact on effects on policy and participant satisfaction is mediated by the process factor deliberation. Further, the capacity of the public administration to steer the advisory council (wardship) mediates negatively the impact of input variables on transparency. The analysis provides a nuanced account of how different input and process design characteristics of participatory institutions have profound direct and indirect effects on their outputs.
Previous research highlighted the beneficial effects of volunteering, income and employment, and religiousness in older adults, but not the interrelationships between these variables and their effects on quality of life. In the present study, 399 community-dwelling retirement-aged New Zealanders completed the WHOQOL-BREF quality of life questionnaire and questions about their volunteering and employment activities. Path-analysis models tested the direct and indirect effects of these variables on quality of life. While employment was not a significant predictor, volunteering was positively associated with physical, psychological, and environment quality of life, and religious community membership predicted psychological and social quality of life, although effects were small. Volunteering did not mediate the relationship between religious community membership and quality of life. Volunteering and religious community membership thus provide independent QOL benefits, and future work may model their unique effects by including measures of feeling a sense of meaning and purpose as potential mediating variables.
This chapter expands on traditional parametric and nonparametric methods by introducing generalized linear models (GLMs) and generalized linear mixed models (GLMMs), which broaden statistical analysis in applied linguistics research. GLMMs, for example, enhance traditional methods by incorporating both fixed and random effects, allowing researchers to account for predictors and grouping factors like subjects or items. This makes GLMMs particularly useful for analyzing complex, hierarchical data in linguistics studies. The chapter introduces linear mixed models (LMMs) before diving into GLMMs, highlighting their advantages in handling complex linguistic data. Practical examples and step-by-step instructions for conducting GLM and GLMM analyses using SPSS are provided, ensuring hands-on experience. Additionally, the chapter briefly overviews advanced multivariate tests, such as factor analysis, path analysis, structural equation modeling (SEM), and introduces Bayesian statistics. While not explored in depth, these methods are presented to underscore their significance in applied linguistics research and encourage their use when appropriate.
No studies have investigated the effects of virtual reality (VR) on the persecutory idea of reference (IOR) or delusions of reference (DOR) in patients with psychosis. This study examined the efficacy and safety of VR therapy in stable outpatients with psychosis and explored relationships between primary outcomes and psychological factors using path analysis.
Methods
Seventy-eight patients were randomly assigned to either the VR-treatment (VR-T) or VR-control (VR-C) group. The VR-T group viewed three 360° 3D videos or four animated videos; the VR-C group viewed the same seven videos with muted voices or 11 360° 3D videos of natural scenes. Pre- and post-assessments were performed using the Psychotic Symptom Rating Scale-Delusions (PSYRATS-D) and Revised Green et al. Paranoid Thought Scale (R-GPTS) as a primary outcome measure. Several self-rating scales measuring schema, depression, brooding, negative evaluation, attribution bias, and self-esteem were administered. Safety was assessed after sessions 1 and 10, and path models were constructed.
Results
Between-group analysis showed a significant improvement in PSYRATS-D scores in the VR-T group compared with the VR-C group. Regarding self-rating scales, the between-group analysis revealed a significant group × time interaction only for the Social and Occupational Functioning Assessment Scale (SOFAS) score. The frequency of VR sickness was high, but its severity was mild. Fear of Negative Evaluation Scale and Beck Depression Inventory scores were found to have mediating roles.
Conclusions
VR therapy effectively reduced delusions in young, stable psychosis patients with mild and tolerable side effects. Future studies should develop diverse VR content for older populations.
A general approach to the analysis of covariance structures is considered, in which the variances and covariances or correlations of the observed variables are directly expressed in terms of the parameters of interest. The statistical problems of identification, estimation and testing of such covariance or correlation structures are discussed.
Several different types of covariance structures are considered as special cases of the general model. These include models for sets of congeneric tests, models for confirmatory and exploratory factor analysis, models for estimation of variance and covariance components, regression models with measurement errors, path analysis models, simplex and circumplex models. Many of the different types of covariance structures are illustrated by means of real data.
The new software package OpenMx 2.0 for structural equation and other statistical modeling is introduced and its features are described. OpenMx is evolving in a modular direction and now allows a mix-and-match computational approach that separates model expectations from fit functions and optimizers. Major backend architectural improvements include a move to swappable open-source optimizers such as the newly written CSOLNP. Entire new methodologies such as item factor analysis and state space modeling have been implemented. New model expectation functions including support for the expression of models in LISREL syntax and a simplified multigroup expectation function are available. Ease-of-use improvements include helper functions to standardize model parameters and compute their Jacobian-based standard errors, access to model components through standard R $ mechanisms, and improved tab completion from within the R Graphical User Interface.
Procedures are given for determining identified parameters, finding constraints on the covariances, and checking equivalence, in acyclic (recursive) linear path models with correlated error terms (disturbances), by inspection of the path equations, aided by simple recursions. This provides a useful and general alternative to the employment of directed acyclic graph theory for such purposes.
Despite the enduring popularity of path analysis, there has been limited research in the context of English Medium of Instruction (EMI) to illustrate established theories. Moreover, researchers have yet to incorporate statistical data to refine the theoretical models and better elucidate the causal relationships between various factors that potentially influence students’ academic achievement. To fill this gap, this study aims to develop and analyze a well-fitted model that could account for contingent links between variables that directly and indirectly affect EMI students’ academic achievement in science. Drawing on survey data from eight EMI secondary schools in Hong Kong, the current study identified interplayed roles of students’ English proficiency, language use in science classroom, self-perceived English difficulty in the science classroom, and self-concept on science learning on science achievement by using path analysis – one of the structural equation modeling (SEM) models, which is also illustrated in Chapter 5 of the book.
Periwinkle (Catharanthus roseus (L.) G. Don) is a vital summer season perennial semi-shrub and multipurpose drought-resilient flower crop of the tropical region of the Indian subcontinent. This industrially dominant crop is primarily used as border, bedding and pot culture in landscaping. There is a lack of information on the genetics of important traits and its correlation with quantitative characters like flower yield and understanding the co-segregation of these traits might be useful in crop improvement. Therefore, the present study was performed using 30 F2 segregating lines of Catharanthus developed from diallel crossing of six genetically dissimilar parents varied in many traits. Phenotyping of population was executed for 12 morphological traits. Results indicated that a significant positive association between days to flowering and plant height (0.753**), and leaf area and number of branches (0.463**) was recorded. Flowers per plant exhibit significantly positive correlation with all attributes except flower diameter (−005). The path coefficient analysis reported solely two traits, such as number of seeds per follicle (0.357) and corolla tube length (0.308) exerted positively significant direct effects on flower yield per plant. The scrutiny of principal components showed that the first three components demonstrated a cumulative variability of 70.1%. The dissipating of F2 plants in bi-plot is impenitent to our prior reports that six inbred lines were genetically diverse and quite different for the characters under study. The current research might be useful in breeding programmes for selection and hybridization of periwinkle in future.
While social determinants of health have been perennially linked to child survival in resource-limited countries, the precise and tested pathways to effect are not clearly understood. The objective of this study was therefore to identify the critical pathways as posited a priori in a model through which social factors (at maternal, household, and community levels) determine neonatal, infant, and under-five mortalities in Nigeria. Using a novel analytic approach (hierarchical path modelling for predicting accelerated failure time) to estimate (in)direct and total effects of social determinants of child survival, we analysed 30,960 live births (weighted data for representativeness), obtained from the 2016/2017 Nigeria Multiple Indicator Cluster Survey. There were three outcome variables: time until occurrence of neonatal, infant, and under-five mortalities. The independent variables were layered factors related to child, maternal, household and community. Geographical region, rurality of residence, infrastructural development, maternal education, contraceptive use, marital status, and maternal age at birth were found to operate more indirectly on neonatal, infant, and under-five survival. Child survival is due to direct effects of child’s sex (female), gestational type (singleton), birth spacing (children whose mothers delivered at least two years apart), and maternal age at delivery (20–34 years). According to the path coefficients, the indirect effects of geographical regions are the most influential determinants of child survival, accounting for 30% (neonatal), 37.1% (infant) and 39.9% (under-five) of the total effects. This study offers comprehensive set of factors, and linked pathways, at the maternal, household, and community levels that are associated with child survival in Nigeria. To accelerate progress towards Sustainable Development Goal targets for child survival and reduce geographical inequities, stakeholders should implement more impactful policies that promote maternal education, contraceptive use and improve living conditions of women (especially in rural areas of northern Nigeria). Future research should focus on identifying the most effective interventions for addressing these social determinants of child survival in Nigeria.
Soil moisture deficit is the major constraint for sesame crop production during its main rainfed and summer cultivation seasons. In summer cultivation, the crop frequently gets exposed to soil moisture deficit at various crop growth stages. Therefore, it is essential to identify the traits along with promising genotypes adapted to soil moisture deficit. A set of 35 sesame genotypes with checks was used to quantify the variation in morpho-physiological, yield, and quality traits under irrigated (WW) and deficit soil moisture stress (WS) conditions in the summer seasons of 2021 and 2022. The analysis of variance revealed the presence of high variability among the genotypes for various measured traits. The mean performance indicated that WS negatively affects the growth, development, yield and quality traits. Moreover, the correlation, path analysis and D2 analysis studies suggested that the traits, viz. leaf area (LA), total dry matter (TDM), canopy temperature (CT), number of branches per plant (NBP) and number of seeds per capsule (NSC) were significantly associated with seed yield under both the conditions. Quality traits like palmitic acid and oleic acid correlated positively with seed yield, particularly under WS. Furthermore, the genotypes with lower canopy temperatures were found to be better seed yielders under WS. In addition, mean performance and cluster analysis suggested that the genotypes: IC- 205776, JSCDT-112, JCSDT-26, IC-205610, and IC-204300, secured higher seed yield along with superior agronomical traits and net photosynthetic rate. These selected genotypes were most promising and could be used in future sesame crop improvement programmes.
In this chapter we present brief discussions of a few statistical topics not covered in earlier chapters. We first cover structural equation models, factor analysis, and path analysis. In future work fitting regression models in the social sciences, we frequently see reference to one or more of them. In the second section of the chapter, we address in summary form a few topics already discussed but which we believe require some additional attention. For instance, as part of our discussion of ordinary least squares regression, we covered in Chapter 8 the topic of regression diagnostics. But regression diagnostics is not an issue applicable only to OLS regression; so we present here a further discussion. Similarly, we expand with some additional commentary our earlier discussions of addressing issues of survey design (covered in Chapter 10) and multilevel models (covered in Chapter 16).
While cannabis use is a well-established risk factor for psychosis, little is known about any association between reasons for first using cannabis (RFUC) and later patterns of use and risk of psychosis.
Methods
We used data from 11 sites of the multicentre European Gene-Environment Interaction (EU-GEI) case–control study. 558 first-episode psychosis patients (FEPp) and 567 population controls who had used cannabis and reported their RFUC.
We ran logistic regressions to examine whether RFUC were associated with first-episode psychosis (FEP) case–control status. Path analysis then examined the relationship between RFUC, subsequent patterns of cannabis use, and case–control status.
Results
Controls (86.1%) and FEPp (75.63%) were most likely to report ‘because of friends’ as their most common RFUC. However, 20.1% of FEPp compared to 5.8% of controls reported: ‘to feel better’ as their RFUC (χ2 = 50.97; p < 0.001). RFUC ‘to feel better’ was associated with being a FEPp (OR 1.74; 95% CI 1.03–2.95) while RFUC ‘with friends’ was associated with being a control (OR 0.56; 95% CI 0.37–0.83). The path model indicated an association between RFUC ‘to feel better’ with heavy cannabis use and with FEPp-control status.
Conclusions
Both FEPp and controls usually started using cannabis with their friends, but more patients than controls had begun to use ‘to feel better’. People who reported their reason for first using cannabis to ‘feel better’ were more likely to progress to heavy use and develop a psychotic disorder than those reporting ‘because of friends’.
Culicoides biting midges (Diptera: Ceratopogonidae) are the main vectors of livestock diseases such as bluetongue (BT) which mainly affect sheep and cattle. In Spain, bluetongue virus (BTV) is transmitted by several Culicoides taxa, including Culicoides imicola, Obsoletus complex, Culicoides newsteadi and Culicoides pulicaris that vary in seasonality and distribution, affecting the distribution and dynamics of BT outbreaks. Path analysis is useful for separating direct and indirect, biotic and abiotic determinants of species' population performance and is ideal for understanding the sensitivity of adult Culicoides dynamics to multiple environmental drivers. Start, end of season and length of overwintering of adult Culicoides were analysed across 329 sites in Spain sampled from 2005 to 2010 during the National Entomosurveillance Program for BTV with path analysis, to determine the direct and indirect effects of land use, climate and host factor variables. Culicoides taxa had species-specific responses to environmental variables. While the seasonality of adult C. imicola was strongly affected by topography, temperature, cover of agro-forestry and sclerophyllous vegetation, rainfall, livestock density, photoperiod in autumn and the abundance of Culicoides females, Obsoletus complex species seasonality was affected by land-use variables such as cover of natural grassland and broad-leaved forest. Culicoides female abundance was the most explanatory variable for the seasonality of C. newsteadi, while C. pulicaris showed that temperature during winter and the photoperiod in November had a strong effect on the start of the season and the length of overwinter period of this species. These results indicate that the seasonal vector-free period (SVFP) in Spain will vary between competent vector taxa and geographic locations, dependent on the different responses of each taxa to environmental conditions.
This chapter summarizes the explanations developed in preceding chapters, fits them into a more comprehensive theoretical framework, and tests them using path analysis, which helps researchers understand causal sequences. Democratization is characterized by punctuated equilibrium. Distant historical factors such as geography and demographic characteristics, together with incrementally changing aspects of social and economic development, affect a country’s level of democracy, but only roughly. Institutions and organizations such as a healthy civil society, the rule of law, and institutionalized political parties, tend to reinforce one another and keep each country’s level of electoral democracy close to an equilibrium or set point. However, short-term economic performance, anti-system movements, and opposition campaigns can sometimes disturb the equilibrium, making significant upturns and downturns possible.
The assessment of environmental identity (EID) in terms of connectedness to nature, eco-friendly behaviour (EFB) and closeness to nature variables is the central focus of this study. The elaborated conceptual model recommends that closeness to nature, connectedness to nature and EFBs related to education, economy and recycling are potential predictors of EID. The sample consists of 518 college students studying in different teacher education programmes. Confirmatory factor analysis was used to evaluate the constructive validity of the scales for each of the measurement models. The theoretical path analysis model was created by considering existing literature. In the present study, the EFBs of the participants had a significant and moderate effect on their EID. Findings confirmed that environmental education behaviours and recycling behaviours had a positive and low effect on EFBs. The results showed that connectedness to nature and closeness to nature had a positive and medium effect on EFB. Promotion of EID sense in pre-service teachers will increase their students’ EID. Finally, advanced degree curricula in environmental protection and nature can be designed and implemented based on target group information.
This study aimed to evaluate the association between legume intake and blood pressure, as well as the mediating role of cardiometabolic risk factors in patients in secondary cardiovascular prevention. Socio-demographic, anthropometric, clinical and food intake data were collected from the baseline of the multicentre study Brazilian Cardioprotective Nutritional Program Trial – BALANCE (RCT: NCT01620398). The relationships between variables were explored through path analysis. In total, 2247 individuals with a median age of 63·0 (45–91) years, 58·8 % (n 1321) male and 96·5 % (n 2168) with diagnosis of hypertension were included. Negative associations were observed between histidine intake and systolic blood pressure (SBP) (standardised coefficient (SC) = −0·057; P = 0·012) and between legume intake and BMI (SC = −0·061; P = 0·006). BMI was positively associated with triglycerides–glucose (TyG) index (SC = 0·173; P < 0·001), SBP (SC = 0·144; P < 0·001) and diastolic blood pressure (DBP) (SC = 0·177; P < 0·001), and TyG index was positively associated with DBP (SC = 0·079; P = 0·001). A negative indirect effect was observed between the intake of legumes, SBP and DBP, mediated by BMI (SC = −0·009; P = 0·011; SC = −0·011; P = 0·010, respectively). In addition, an indirect negative effect was found between the intake of legumes and the DBP, mediated simultaneously by BMI and TyG index (SC = −0·001; P = 0·037). In conclusion, legume intake presented a negative indirect association with blood pressure, mediated by insulin resistance (TyG) and adiposity (BMI) in individuals of secondary care in cardiology.
Stouffer was one of the first of Ogburn’s graduate students, Duncan one of the last. Duncan took over most of Ogburn’s views on the requirements for sociological science but his main achievement was to go beyond Ogburn in progressively working out over the course of his career just what kind of science sociology should aim to be: that is, a population science. This idea first emerged in his collaboration with Philip Hauser in editing a large collection of papers, The Study of Population, and was then developed in his research on social stratification and mobility and, in particular, in relation to his methodological contributions, notably path analysis. Duncan saw the role of regression techniques in sociology as a population science not as a means of determining causation but of describing systematic population variability in regard to an outcome of interest. And subsequently, as his interests turned to the use of loglinear models in the analysis of contingency tables, including mobility tables, he again emphasised their descriptive importance in serving to bring out regularities emergent from individual action that were the properties of populations.
To examine the direct and indirect effects of age, APOE ϵ4 genotype, amyloid positivity, and volumetric reductions in AD-prone brain regions as it relates to semantic intrusion errors reflecting proactive semantic interference (PSI) and the failure to recover from proactive semantic interference (frPSI) on the Loewenstein-Acevedo Scales of Semantic Interference and Learning (LASSI-L), a cognitive stress test that has been consistently more predictive of preclinical and prodromal Alzheimer’s disease (AD) than traditional list-learning tests.
Design:
Cross-sectional study.
Setting:
1Florida Alzheimer’s Disease Research Center baseline study.
Participants:
Two-hundred and twelve participants with Mini-Mental State Examination (MMSE) score above 16 and a broad array of cognitive diagnoses ranging from cognitively normal (CN) to dementia, of whom 58% were female, mean age of 72.1 (SD 7.9).
Measures:
Participants underwent extensive clinical and neuropsychological evaluations, MR and amyloid Positron Emission Tomography/Computer/Computer Tomography (PET/CT) imaging, and analyses of APOE ϵ4 genotype. Confirmatory path analyses were conducted in the structural equation modeling framework that estimated multiple equations simultaneously while controlling for important covariates such as sex, education, language of evaluation, and global cognitive impairment.
Results:
Both amyloid positivity and decreased brain volumes in AD-prone regions were directly related to LASSI-L Cued B1 and Cued B2 intrusions (sensitive to PSI and frPSI effects) even after controlling for covariates. APOE ϵ4 status did not evidence direct effects on these LASSI-L cognitive markers, but rather exerted their effects on amyloid positivity, which in turn related to PSI and frPSI. Similarly, age did not have a direct relationship with LASSI-L scores, but exerted its effects indirectly through amyloid positivity and volumes of AD-prone brain regions.
Conclusions:
Our study provides insight into the relationships among age, APOE ϵ4, amyloid, and brain volumetric reductions as it relates to semantic intrusion errors. The investigation expands our understanding of the underpinnings of PSI and frPSI intrusions in a large cohort.
Dispersal is a key ecological process affecting community dynamics and the maintenance of populations. There is increasing awareness of the need to understand individual dispersal potential to better inform population-level dispersal, allowing more accurate models of the spread of invasive and beneficial insects, aiding crop and pest management strategies. Here, fine-scale movements of Poecilus cupreus, an important agricultural carabid predator, were recorded using a locomotion compensator and key movement characteristics were quantified. Net displacement increased more rapidly than predicted by a simple correlated random walk model with near ballistic behaviour observed. Individuals displayed a latent ability to head on a constant bearing for protracted time periods, despite no clear evidence of a population level global orientation bias. Intermittent bouts of movement and non-movement were observed, with both the frequency and duration of bouts of movement varying at the inter- and intra-individual level. Variation in movement behaviour was observed at both the inter- and intra- individual level. Analysis suggests that individuals have the potential to rapidly disperse over a wider area than predicted by simple movement models parametrised at the population level. This highlights the importance of considering the role of individual variation when analysing movement and attempting to predict dispersal distances.