Threshold Effect in Crowdfunding: Evidence from Investment-Level Data

2021 ◽  
Vol 25 (4) ◽  
pp. 416-439
Author(s):  
Yang Xu ◽  
Wen Song ◽  
Gong-bing Bi ◽  
Qiang Zhou
Keyword(s):  
Threshold Effect ◽  
Level Data ◽  
Investment Level

scholarly journals Threshold-effect of income on periodontitis and interactions with race/ethnicity and education

2019 ◽  
Vol 22 ◽  
Author(s):  
Roger Keller Celeste ◽  
Sara Cioccari Oliveira ◽  
Roger Junges
Keyword(s):  
Multivariable Analysis ◽  
Threshold Effect ◽  
Or Education ◽  
Periodontal Health ◽  
Individual Level ◽  
Level Data ◽  
Severe Periodontitis ◽  
Race Ethnicity ◽  
Independent Effects ◽  
The Relationship

ABSTRACT: Objectives: The aims of this study were to explore the shape of the relationship of income and education with periodontal health, and to assess the interactions between them and race/ethnicity. Method: Individual level data from the Brazilian National Oral Health Survey in 2010 (Pesquisa Nacional de Saúde Bucal-SB Brasil 2010) were obtained for 9,779 subjects. Relations between per capita income and education with periodontal health were smoothed using Locally Weighted Scatter-plot Smoother (Lowess) technique. Multivariable logistic regression was used to assess independent effects of income, education, race/ethnicity adjusted for age, sex and time since last dental appointment. Results: Prevalence of adults with moderate to severe and severe periodontitis was 17.6 and 6.5%, respectively. The relationship between periodontal health and income was curvilinear, showing a threshold of no relationship for income levels higher than US$ 600/month. In multivariable analysis, after controlling for covariates, only income was significantly associated with periodontal health. There was no significant interaction of income with race or education, neither between race and education. Conclusion: The relation between periodontal health and income was curvilinear and indicated the presence of a threshold, supporting income transfer programs. Beyond the threshold, only education presented a negative linear relationship with moderate to severe periodontitis.

New Evidence on the Construct Validity of the ASI-3 and the Dimensional Conceptualization of Trait Anxiety Sensitivity From IRT Modeling

2017 ◽  
Vol 33 (3) ◽  
pp. 181-189 ◽  
Author(s):  
Christoph J. Kemper ◽  
Michael Hock
Keyword(s):  
Construct Validity ◽  
Anxiety Sensitivity ◽  
Latent Class ◽  
Dimensional Structure ◽  
Sensitivity Index ◽  
Response Scale ◽  
Established Risk Factor ◽  
Irt Models ◽  
Level Data ◽  
Extreme Response

Abstract. Anxiety Sensitivity (AS) denotes the tendency to fear anxiety-related sensations. Trait AS is an established risk factor for anxiety pathology. The Anxiety Sensitivity Index-3 (ASI-3) is a widely used measure of AS and its three most robust dimensions with well-established construct validity. At present, the dimensional conceptualization of AS, and thus, the construct validity of the ASI-3 is challenged. A latent class structure with two distinct and qualitatively different forms, an adaptive form (normative AS) and a maladaptive form (AS taxon, predisposing for anxiety pathology) was postulated. Item Response Theory (IRT) models were applied to item-level data of the ASI-3 in an attempt to replicate previous findings in a large nonclinical sample (N = 2,603) and to examine possible interpretations for the latent discontinuity observed. Two latent classes with a pattern of distinct responses to ASI-3 items were found. However, classes were indicative of participant’s differential use of the response scale (midpoint and extreme response style) rather than differing in AS content (adaptive and maladaptive AS forms). A dimensional structure of AS and the construct validity of the ASI-3 was supported.

Modeling Intraindividual Variability in Three-Level Multilevel Models

Methodology ◽  
2018 ◽  
Vol 14 (3) ◽  
pp. 95-108 ◽  
Author(s):  
Steffen Nestler ◽  
Katharina Geukes ◽  
Mitja D. Back
Keyword(s):  
Multilevel Model ◽  
Multilevel Models ◽  
Mixed Effects ◽  
Repeated Measurements ◽  
Scale Model ◽  
Suggested Approach ◽  
Psychological Study ◽  
Level Data ◽  
Ecological Momentary ◽  
Momentary Assessment

Abstract. The mixed-effects location scale model is an extension of a multilevel model for longitudinal data. It allows covariates to affect both the within-subject variance and the between-subject variance (i.e., the intercept variance) beyond their influence on the means. Typically, the model is applied to two-level data (e.g., the repeated measurements of persons), although researchers are often faced with three-level data (e.g., the repeated measurements of persons within specific situations). Here, we describe an extension of the two-level mixed-effects location scale model to such three-level data. Furthermore, we show how the suggested model can be estimated with Bayesian software, and we present the results of a small simulation study that was conducted to investigate the statistical properties of the suggested approach. Finally, we illustrate the approach by presenting an example from a psychological study that employed ecological momentary assessment.

Hyperstimulation of the immune system as a cause of autoimmune diseases

2020 ◽  
Vol 75 (3) ◽  
pp. 204-213
Author(s):  
Varvara A. Ryabkova ◽  
Leonid P. Churilov ◽  
Yehuda Shoenfeld
Keyword(s):  
Immune System ◽  
Autoimmune Diseases ◽  
Genetic Basis ◽  
Threshold Model ◽  
Subsequent Development ◽  
Threshold Effect ◽  
Successful Management ◽  
Polygenic Inheritance ◽  
Autoimmune Pathology ◽  
The Common

The pathogenesis of autoimmune diseases is very complex and multi-factorial. The concept of Mosaics of Autoimmunity was introduced to the scientific community 30 years ago by Y. Shoenfeld and D.A. Isenberg, and since then new tiles to the puzzle are continuously added. This concept specifies general pathological ideas about the multifactorial threshold model for polygenic inheritance with a threshold effect by the action of a number of external causal factors as applied to the field of autoimmunology. Among the external factors that can excessively stimulate the immune system, contributing to the development of autoimmune reactions, researchers are particularly interested in chemical substances, which are widely used in pharmacology and medicine. In this review we highlight the autoimmune dynamics i.e. a multistep pathogenesis of autoimmune diseases and the subsequent development of lymphoma in some cases. In this context several issues are addressed namely, genetic basis of autoimmunity; environmental immunostimulatory risk factors; gene/environmental interaction; pre-clinical autoimmunity with the presence of autoantibodies; and the mechanisms, underlying lymphomagenesis in autoimmune pathology. We believe that understanding the common model of the pathogenesis of autoimmune diseases is the first step to their successful management.

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