response models
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2022 ◽  
Vol 28 (1) ◽  
pp. 10-13
Hua Tian

ABSTRACT Introduction: The main purpose of aerobic exercise is to enhance cardiopulmonary endurance, so it is necessary to build cardiopulmonary endurance response models based on different frequencies of aerobic exercise. Objective: To study the cardiopulmonary endurance response of women to different frequencies of aerobic exercise. Methods: Twenty young female desk workers (female teachers and civil servants) who worked out at a fitness club were randomly divided into two groups. Cardiopulmonary function, both before and after 16 weeks of aerobic exercise at different exercise loads, was studied and analyzed. Results: After 16 weeks of aerobic exercise at different exercise loads, all the young women had significantly improved their vital capacity (VC), and their maximum oxygen uptake ability was improved to a certain extent. Compared with the 45-minute aerobic exercise group, the vital capacity (VC)of 90-minute aerobic exercise group was significantly increased (P>0.05). Conclusions: When performed at a consistent frequency level, aerobic exercise with a relatively high exercise load can better develop the body’s respiratory system function. This may be due to deep stimulation of the respiratory system from high-load aerobic exercise, and ultimately to the intensive exercising of lung function. Level of evidence II; Therapeutic studies - investigation of treatment results.

2021 ◽  
pp. 001316442110618
Brooke E. Magnus ◽  
Yang Liu

Questionnaires inquiring about psychopathology symptoms often produce data with excess zeros or the equivalent (e.g., none, never, and not at all). This type of zero inflation is especially common in nonclinical samples in which many people do not exhibit psychopathology, and if unaccounted for, can result in biased parameter estimates when fitting latent variable models. In the present research, we adopt a maximum likelihood approach in fitting multidimensional zero-inflated and hurdle graded response models to data from a psychological distress measure. These models include two latent variables: susceptibility, which relates to the probability of endorsing the symptom at all, and severity, which relates to the frequency of the symptom, given its presence. After estimating model parameters, we compute susceptibility and severity scale scores and include them as explanatory variables in modeling health-related criterion measures (e.g., suicide attempts, diagnosis of major depressive disorder). Results indicate that susceptibility and severity uniquely and differentially predict other health outcomes, which suggests that symptom presence and symptom severity are unique indicators of psychopathology and both may be clinically useful. Psychometric and clinical implications are discussed, including scale score reliability.

2021 ◽  
pp. 1-18
Gudeta W. Sileshi

Summary Optimisation of fertiliser use and site-specific nutrient management are increasingly becoming critical because of the growing need to balance agricultural productivity with the growing demand for food and environmental concerns. Trials to determine responses of crops to fertilisers have been widely conducted in sub-Saharan Africa (SSA) with increasing emphasis on the development of economically optimum rates (EORs). Computation of EORs depends on accurate estimation of both the optimum nutrient rate and the agronomic maximum yield response; however, estimation of nutrient-response parameters and EORs is beset by a number of problems. Therefore, the objectives of this paper were to (1) point out common problems in the development and use of nutrient dose-response models and (2) provide corrective measures to facilitate future trial design and data analysis. This review outlines the underlying assumptions, strengths and limitations of the various response functions in order to facilitate informed choices by practitioners. Using specific examples, it also shows that (1) the commonly used trial designs do not allow examination of interactions between two or more nutrients and (2) trial designs with ≤5 nutrient levels and wide spacing between the levels result in large uncertainty in dose-response parameters. The key recommendations emerging from the review are as follows: (1) factorial designs and response surface models should be used more widely to address interactions between nutrients; (2) a minimum of six carefully spaced nutrient levels should be used to correctly estimate dose-response parameters; and (3) when locating field trials, Reference Soil Groups and cropping history should be carefully considered to produce site-specific EORs.

2021 ◽  
Vol 9 ◽  
Mark Novak ◽  
Daniel B. Stouffer

The assessment of relative model performance using information criteria like AIC and BIC has become routine among functional-response studies, reflecting trends in the broader ecological literature. Such information criteria allow comparison across diverse models because they penalize each model's fit by its parametric complexity—in terms of their number of free parameters—which allows simpler models to outperform similarly fitting models of higher parametric complexity. However, criteria like AIC and BIC do not consider an additional form of model complexity, referred to as geometric complexity, which relates specifically to the mathematical form of the model. Models of equivalent parametric complexity can differ in their geometric complexity and thereby in their ability to flexibly fit data. Here we use the Fisher Information Approximation to compare, explain, and contextualize how geometric complexity varies across a large compilation of single-prey functional-response models—including prey-, ratio-, and predator-dependent formulations—reflecting varying apparent degrees and forms of non-linearity. Because a model's geometric complexity varies with the data's underlying experimental design, we also sought to determine which designs are best at leveling the playing field among functional-response models. Our analyses illustrate (1) the large differences in geometric complexity that exist among functional-response models, (2) there is no experimental design that can minimize these differences across all models, and (3) even the qualitative nature by which some models are more or less flexible than others is reversed by changes in experimental design. Failure to appreciate model flexibility in the empirical evaluation of functional-response models may therefore lead to biased inferences for predator–prey ecology, particularly at low experimental sample sizes where its impact is strongest. We conclude by discussing the statistical and epistemological challenges that model flexibility poses for the study of functional responses as it relates to the attainment of biological truth and predictive ability.

2021 ◽  
Vol 11 (12) ◽  
Lawrence Obidike ◽  
Ezekiel Madigoe

AbstractIn this study, a wastewater treatment program was developed and optimized for the treatment of sewage wastewater. Central composite face design (CCFD) and response surface methodology (RSM) were utilized to develop the experimental design and to establish the relationship between the independent variables (coagulant and flocculant dosage) and responses (turbidity and total dissolved solids removal). Statistical analysis showed that the developed response models were accurate. Optimal removal efficiencies of 93.3% and 23.2% for turbidity and TDS, respectively, were obtained under the optimal conditions for coagulant (120.9 ppm of U6750) and flocculant (125 ppm of Floc887) dosage. This showed that the developed treatment using the coagulant, U6750 and flocculant, Floc887 improved the physical characteristics of the wastewater.

2021 ◽  
Vol 22 (1) ◽  
Yiran Zhang ◽  
Kellie J. Archer

Abstract Background Acute myeloid leukemia (AML) is a heterogeneous cancer of the blood, though specific recurring cytogenetic abnormalities in AML are strongly associated with attaining complete response after induction chemotherapy, remission duration, and survival. Therefore recurring cytogenetic abnormalities have been used to segregate patients into favorable, intermediate, and adverse prognostic risk groups. However, it is unclear how expression of genes is associated with these prognostic risk groups. We postulate that expression of genes monotonically associated with these prognostic risk groups may yield important insights into leukemogenesis. Therefore, in this paper we propose penalized Bayesian ordinal response models to predict prognostic risk group using gene expression data. We consider a double exponential prior, a spike-and-slab normal prior, a spike-and-slab double exponential prior, and a regression-based approach with variable inclusion indicators for modeling our high-dimensional ordinal response, prognostic risk group, and identify genes through hypothesis tests using Bayes factor. Results Gene expression was ascertained using Affymetrix HG-U133Plus2.0 GeneChips for 97 favorable, 259 intermediate, and 97 adverse risk AML patients. When applying our penalized Bayesian ordinal response models, genes identified for model inclusion were consistent among the four different models. Additionally, the genes included in the models were biologically plausible, as most have been previously associated with either AML or other types of cancer. Conclusion These findings demonstrate that our proposed penalized Bayesian ordinal response models are useful for performing variable selection for high-dimensional genomic data and have the potential to identify genes relevantly associated with an ordinal phenotype.

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