Causal Modeling Analysis Research Articles

Effect of Anthropogenic Landscape Features on Population Genetic Differentiation of Przewalski's Gazelle: Main Role of Human Settlement

Anthropogenic landscapes influence evolutionary processes such as population genetic differentiation, however, not every type of landscape features exert the same effect on a species, hence it is necessary to estimate their relative effect for species management and conservation. Przewalski's gazelle (Procapra przewalskii), which inhabits a human-altered area on Qinghai-Tibet Plateau, is one of the most endangered antelope species in the world. Here, we report a landscape genetic study on Przewalski's gazelle. We used skin and fecal samples of 169 wild gazelles collected from nine populations and thirteen microsatellite markers to assess the genetic effect of anthropogenic landscape features on this species. For comparison, the genetic effect of geographical distance and topography were also evaluated. We found significant genetic differentiation, six genetic groups and restricted dispersal pattern in Przewalski's gazelle. Topography, human settlement and road appear to be responsible for observed genetic differentiation as they were significantly correlated with both genetic distance measures [FST/(1−FST) and F′ST/(1−F′ST)] in Mantel tests. IBD (isolation by distance) was also inferred as a significant factor in Mantel tests when genetic distance was measured as FST/(1−FST). However, using partial Mantel tests, AICc calculations, causal modeling and AMOVA analysis, we found that human settlement was the main factor shaping current genetic differentiation among those tested. Altogether, our results reveal the relative influence of geographical distance, topography and three anthropogenic landscape-type on population genetic differentiation of Przewalski's gazelle and provide useful information for conservation measures on this endangered species.

Why do blind listeners use visual cortex for understanding ultra-fast speech?

Individuals with vision impairment of a peripheral, e.g., retinal origin, may learn to understand spoken language at a rate of up to 22 syllables (syl) per second, exceeding by far the maximum performance level of sighted listeners (ca. 8 syl/s). To delineate the brain network subserving this skill, 14 blind individuals (different proficiency in understanding ultra-fast speech) and a sighted control group underwent functional magnetic resonance imaging. In addition to perisylvian cortex and left-hemisphere supplementary motor area (SMA), significant hemodynamic activation of right-hemisphere primary visual cortex (V1), left-hemisphere fusiform gyrus (FG), and bilateral pulvinar emerged during ultra-fast speech perception (16 syl/s) in trained blind people. Dynamic causal modeling analysis revealed skill-dependent intrinsic connections from Heschl’s gyrus (right > left) and pulvinar to V1, from V1 to perisylvian areas and SMA as well as from FG to Broca’s area. Conceivably, cooperation of right-hemisphere Heschl’s gyrus, V1, and left SMA enhances the temporal sequencing of syllable structure of ultra-fast utterances which, in turn, accelerates the segmentation of speech sounds at the level of perisylvian cortex and left-hemisphere FG. The pulvinar—an audiovisual relais station–might support the synchronization of V1 activity with central-auditory processing. [Work supported by the German Research Foundation (DFG; SFB 550/B1) and the Hertie Institute for Clinical Brain Research, Tuebingen.]

A dynamic causal modeling analysis of the effective connectivities underlying top-down letter processing

The present study employed dynamic causal modeling to investigate the effective functional connectivity between regions of the neural network involved in top-down letter processing. We used an illusory letter detection paradigm in which participants detected letters while viewing pure noise images. When participants detected letters, the response of the right middle occipital gyrus (MOG) in the visual cortex was enhanced by increased feed-backward connectivity from the left inferior frontal gyrus (IFG). In addition, illusory letter detection increased feed-forward connectivity from the right MOG to the left inferior parietal lobules. Originating in the left IFG, this top-down letter processing network may facilitate the detection of letters by activating letter processing areas within the visual cortex. This activation in turns may highlight the visual features of letters and send letter information to activate the associated phonological representations in the identified parietal region.

Personality and Social Psychology Factors Explaining Sexism

Previous research has almost exclusively examined sexism (negative attitudes toward women) from either a personality or a social-psychology perspective. In two studies (N = 379 and 182, respectively), we combine these perspectives and examine whether sexism is best explained by personality (Big-Five factors, social dominance orientation, and right-wing authoritarianism) or by social-psychological (group membership and group identification) variables – or by a combination of both approaches. Causal modeling and multiple regression analyses showed that, with the present set of variables, sexism was best explained by considering the combined influence of both personality- and social-psychology constructs. The findings imply that it is necessary to integrate various approaches to explain prejudice.

Functional and Effective Connectivity: A Review

Over the past 20 years, neuroimaging has become a predominant technique in systems neuroscience. One might envisage that over the next 20 years the neuroimaging of distributed processing and connectivity will play a major role in disclosing the brain's functional architecture and operational principles. The inception of this journal has been foreshadowed by an ever-increasing number of publications on functional connectivity, causal modeling, connectomics, and multivariate analyses of distributed patterns of brain responses. I accepted the invitation to write this review with great pleasure and hope to celebrate and critique the achievements to date, while addressing the challenges ahead.

Drivers of sales performance: a contemporary meta-analysis. Have salespeople become knowledge brokers?

It has been 25 years since the publication of a comprehensive review of the full spectrum of sales-performance drivers. This study takes stock of the contemporary field and synthesizes empirical evidence from the period 1982–2008. The authors revise the classification scheme for sales performance determinants devised by Walker et al. (1977) and estimate both the predictive validity of its sub-categories and the impact of a range of moderators on determinant-sales performance relationships. Based on multivariate causal model analysis, the results make two major observations: (1) Five sub-categories demonstrate significant relationships with sales performance: selling-related knowledge (β = .28), degree of adaptiveness (β = .27), role ambiguity (β = −.25), cognitive aptitude (β = .23) and work engagement (β = .23). (2) These sub-categories are moderated by measurement method, research context, and sales-type variables. The authors identify managerial implications of the results and offer suggestions for further research, including the conjecture that as the world is moving toward a knowledge-intensive economy, salespeople could be functioning as knowledge-brokers. The results seem to back this supposition and indicate how it might inspire future research in the field of personal selling.

Empirical model and analysis of mastery and performance‐approach goals: a developmental approach

This study used latent growth modelling (LGM) to explore the developmental course and longitudinal relationships between achievement goals (mastery and performance‐approach) and academic performance over a three‐year period (four time‐points of data collection). Three hundred and fifty‐two university students (152 women, 200 men) who first enrolled in 2006 took part in this study. Likert‐scale inventories were used to elicit relevant data from students. Academic performance was collated from students' course and final exam marks in two different undergraduate courses. LISREL 8.72 and SPSS 17 were used to test and evaluate the conceptual model proposed. Causal modelling analyses indicated the temporally displaced effects of mastery and performance‐approach goals on academic performance. The results indicated that individuals' mastery goals increased over time, whereas there was no increase in growth change with performance‐approach goals. Causal modelling also indicated: (1) performance‐approach goals → academic performance → mastery goals relationship and (2) mastery goals → academic performance → mastery goals relationship. Finally, the use of LGM provided a clearer perspective concerning the developmental trajectories of mastery goals over time.

Analysis of causal models of diet for patients with head and neck cancer receiving radiation therapy

Purpose This study seeks to establish causal models of diet which maintain the appetite of head and neck cancer patients receiving radiation therapy. Sample and methods We collected data from 208 patients at two radiation doses, 30/50 Gy, using a questionnaire on appetite and analyzed the items using structural equation modeling. Results In the causal model for 30 Gy, we established a path using the four intervening variables “ease of consuming foods in smooth forms,” “ease of consuming foods with a chewable texture and suitable temperature,” “ease of consuming lightly seasoned foods with a flavorful smell,” and “overall ease of consuming a given meal” from the temporal relationship between “dietary preferences” and “maintaining appetite while caring for the oral cavity.” In the causal model for 50 Gy, we established a path between “ease of consuming foods with a mild temperature and smell,” and “maintaining appetite while caring for the oral cavity” using the four intervening variables “ease of consuming foods that are easy to swallow,” “ease of consuming foods that dissolve well in the mouth,” “ease of consuming foods with a mild taste,” and “overall ease of consuming a given meal.” The goodness of fit indices for both models were above 0.85 for both the goodness of fit index (GFI) and adjusted GFI (AGFI), and less than 0.08 for root mean square error of approximation (RMSEA), indicating a satisfactory goodness of fit. Conclusions Food characteristics help to maintain patient appetite at cumulative radiation doses of 30/50 Gy.

Environmental dynamism, human resource flexibility, and firm performance: analysis of a multi-level causal model

While strategic HRM scholars have conceptualized HR flexibility as an important source of sustainable superior firm performance in dynamic environments, the process through which HR flexibility creates value for the firm has not been empirically investigated. Based on a study of 98 manufacturing and 103 service firms from a wide array of industries in India, this paper attempts to illuminate the black box of causal linkages between environmental dynamism, flexibility of human assets, and firm level human-, operational-, and financial-outcomes by developing and testing a multi-level causal model. Evidence indicates that HR flexibility mediates the influence of environmental dynamism on firm performance and that irrespective of the nature of the industry and the degree of environmental turbulence, superior firm performance ensues when HR flexibility as actually possessed by the firm matches the environmental demands for such flexibility as perceived by the firm managers. The results also support the notion of HR value chain that postulates that HR system has direct impact on firm-level HR outcomes which are most proximal, and its effects on increasingly more distal operational- and financial-outcomes are mediated by HR outcomes. The findings of the study suggest that HR practices as a system have both direct and indirect (mediated by behavioral flexibility) effects on firm-level HR outcomes. Existence of significant direct effects signifies that HR practices play an important role as a structural mechanism in achieving superior firm performance.

Analysis of Hypothetical Causal Model on the Academic Performance of Elementary Schoolers who Participate in Taekwondo Training

Analysis of Hypothetical Causal Model on the Academic Performance of Elementary Schoolers who Participate in Taekwondo Training

The differential effect of the teacher–student interpersonal relationship on student outcomes for students with different ethnic backgrounds

The differential effectiveness of schools and teachers receives a growing interest, but few studies focused on the relevance of student ethnicity for this effectiveness and only a small number of these studies investigated teaching in terms of the teacher-student interpersonal relationship. Furthermore, the methodology employed often restricted researchers to investigating direct effects between variables across large samples of students. This study uses causal modelling to investigate associations between student background characteristics, students' perceptions of the teacher-student interpersonal relationship, and student outcomes, across and within several population subgroups in Dutch secondary multi-ethnic classes. Multi-group structural equation modelling was used to investigate causal paths between variables in four ethnic groups: Dutch (N=387), Turkish first- and second-generation immigrant students (N=267), Moroccan first and second generation (N=364), and Surinamese second-generation students (N=101). Different structural paths were necessary to explain associations between variables in the different (sub) groups. Different amounts of variance in student attitudes could be explained by these variables. The teacher-student interpersonal relationship is more important for students with a non-Dutch background than for students with a Dutch background. Results suggest that the teacher-student relationship is more important for second generation than for first-generation immigrant students. Multi-group causal model analyses can provide a better, more differentiated picture of the associations between student background variables, teacher behaviour, and student outcomes than do more traditional types of analyses.

Physical heterogeneity increases biofilm resource use and its molecular diversity in stream mesocosms.

BackgroundEvidence increasingly shows that stream ecosystems greatly contribute to global carbon fluxes. This involves a tight coupling between biofilms, the dominant form of microbial life in streams, and dissolved organic carbon (DOC), a very significant pool of organic carbon on Earth. Yet, the interactions between microbial biodiversity and the molecular diversity of resource use are poorly understood.Methodology/Principal FindingsUsing six 40-m-long streamside flumes, we created a gradient of streambed landscapes with increasing spatial flow heterogeneity to assess how physical heterogeneity, inherent to streams, affects biofilm diversity and DOC use. We determined bacterial biodiversity in all six landscapes using 16S-rRNA fingerprinting and measured carbon uptake from glucose and DOC experimentally injected to all six flumes. The diversity of DOC molecules removed from the water was determined from ultrahigh-resolution Fourier Transform Ion Cyclotron Resonance mass spectrometry (FTICR-MS). Bacterial beta diversity, glucose and DOC uptake, and the molecular diversity of DOC use all increased with increasing flow heterogeneity. Causal modeling and path analyses of the experimental data revealed that the uptake of glucose was largely driven by physical processes related to flow heterogeneity, whereas biodiversity effects, such as complementarity, most likely contributed to the enhanced uptake of putatively recalcitrant DOC compounds in the streambeds with higher flow heterogeneity.Conclusions/SignificanceOur results suggest biophysical mechanisms, including hydrodynamics and microbial complementarity effects, through which physical heterogeneity induces changes of resource use and carbon fluxes in streams. These findings highlight the importance of fine-scale streambed heterogeneity for microbial biodiversity and ecosystem functioning in streams, where homogenization and loss of habitats increasingly reduce biodiversity.

"Splitting of the Mind" Revisited: Recent Neuroimaging Evidence for Functional Dysconnection in Schizophrenia and Its Relation to Symptoms

"Splitting of the Mind" Revisited: Recent Neuroimaging Evidence for Functional Dysconnection in Schizophrenia and Its Relation to Symptoms

Consumer Innovativeness for Fashion as a Second Order Construct: A Cross-Cultural Study

Abstract Setting and changing prices is difficult for marketing managers, especially for new products. Consumer price sensitivity (how consumers react to prices or to price changes) makes a difference in the likelihood consumers will buy (Ainslie and Rossi 1998). For many new products, the reactions of the earliest buyers or innovative consumers are critical to success (e.g., Munnukka 2005). But how important is the price of new products to innovators? The answer to this question is of theoretical interest and of practical importance to marketers, especially when marketing new fashions, where innovators play a crucial role in consumer acceptance. Existing research shows that innovators are relatively less sensitive to prices of new products than are later adopters; that is, they are more willing to pay higher prices (Goldsmith 1996, 1999). However, the evidence in favor of the negative relationship between innovativeness and price sensitivity is based largely on studies that conceptualize and measure inno...

Factors influencing the adoption of mobile service in China: An integration of TAM

This study based on the technology acceptance model(TAM) and theory of planned be haviour (TPB) presents an extended TAM that integrates trust related construct (‘perceived credibility’) and resource-related constructs (‘perceived cost’) into the TAM to analyzing adoption behavior of mobile service . The proposed model was empirically tested using data collected from a survey of mobile service consumers. The structural equation modeling technique was used to evaluate the causal model and confirmatory factor analysis was performed to examine the reliability and validity of the measurement model. Our findings indicated that all variables except perceived ease of use significantly affected users’ behavioral intent ion . The implication of this work to both researchers and practitioners is discussed.

Sadness enhances the experience of pain via neural activation in the anterior cingulate cortex and amygdala: An fMRI study

Pain is a multidimensional experience. Human pain perception can be modulated by subjective emotional responses. We examined this association within the context of a neuroimaging study, using functional MRI to examine neural responses to electrical pain-inducing stimuli in 15 healthy subjects (6 females; age range=20–30 years). Pain-inducing stimuli were presented during different emotional contexts, which were induced via the continuous presentation (5 s) of sad, happy, or neutral pictures of faces. We found that subjective pain ratings were higher in the sad emotional context than in the happy and neutral contexts, and that pain-related activation in the ACC was more pronounced in the sad context relative to the happy and neutral contexts. Psychophysiological interaction (PPI) and dynamic causal modeling (DCM) analyses demonstrated amygdala to ACC connections during the experience of pain in the sad context. These findings serve to highlight the neural mechanisms that may be relevant to understanding the broader relationship between somatic complaints and negative emotion.

Analysis of Hypothetical Causal Model on the Satisfaction with Life of Leisure Dance Participants

Analysis of Hypothetical Causal Model on the Satisfaction with Life of Leisure Dance Participants

Analysis of Hypothetical Causal Model on the Academic Performance of Elementary Schoolers who Participate in Taekwondo Training

Analysis of Hypothetical Causal Model on the Academic Performance of Elementary Schoolers who Participate in Taekwondo Training

Eyes Wide Shut: Amygdala Mediates Eyes-Closed Effect on Emotional Experience with Music

The perceived emotional value of stimuli and, as a consequence the subjective emotional experience with them, can be affected by context-dependent styles of processing. Therefore, the investigation of the neural correlates of emotional experience requires accounting for such a variable, a matter of an experimental challenge. Closing the eyes affects the style of attending to auditory stimuli by modifying the perceptual relationship with the environment without changing the stimulus itself. In the current study, we used fMRI to characterize the neural mediators of such modification on the experience of emotionality in music. We assumed that closed eyes position will reveal interplay between different levels of neural processing of emotions. More specifically, we focused on the amygdala as a central node of the limbic system and on its co-activation with the Locus Ceruleus (LC) and Ventral Prefrontal Cortex (VPFC); regions involved in processing of, respectively, ‘low’, visceral-, and ‘high’, cognitive-related, values of emotional stimuli. Fifteen healthy subjects listened to negative and neutral music excerpts with eyes closed or open. As expected, behavioral results showed that closing the eyes while listening to emotional music resulted in enhanced rating of emotionality, specifically of negative music. In correspondence, fMRI results showed greater activation in the amygdala when subjects listened to the emotional music with eyes closed relative to eyes open. More so, by using voxel-based correlation and a dynamic causal model analyses we demonstrated that increased amygdala activation to negative music with eyes closed led to increased activations in the LC and VPFC. This finding supports a system-based model of perceived emotionality in which the amygdala has a central role in mediating the effect of context-based processing style by recruiting neural operations involved in both visceral (i.e. ‘low’) and cognitive (i.e. ‘high’) related processes of emotions.

Dynamic causal modeling analysis indicates drug-related changes in the amygdala-centered emotional processing circuitry

Dynamic causal modeling analysis indicates drug-related changes in the amygdala-centered emotional processing circuitry