scholarly journals Sources and routes from terrestrial exogenous pollutants affect phytoplankton biomass in reservoir bays

2021 ◽  
Author(s):  
R. Y. Hu
Keyword(s):  
Phytoplankton Biomass ◽  
Structural Equation ◽  
Storage Period ◽  
Equation Model ◽  
Total Effect ◽  
Total Contribution ◽  
Soil Release ◽  
Anthropogenic Discharge ◽  
Water Nutrients ◽  
Water Eutrophication

Abstract Reservoir bays, the boundary of terrestrial and water where water fluidity slows down and self-purification ability turn weak, hence they are especially sensitive to terrestrial exogenous pollutants, even resulting in eutrophication. According to N:P, water nutrients types can be divided into N limited, P limited and N + P limited classes. Phytoplankton biomass is represented by chlorophyll a, which is one of the sensitive indicators of water eutrophication. Comprehensively traced non-point pollution from terrestrial exogenous pollutants (fertilizer, soil release, anthropogenic discharge) to water nutrients that happen in reservoir bays is of great significance. This paper identified the dominant environmental variables and nutrients limited types of reservoir bays at storage and discharge periods, constructed partial least squares structural equation model (PLS-SEM) to explore the impacts of terrestrial exogenous pollutants. Results showed that in storage period water contamination mainly came from residential discharge and soil endogenous release, the total contribution rate reached 61%. In discharge period, with the increase of rainfall – runoff erosion, the explanatory ability of land use, topography and landscape pattern to water quality increased, up to 58%. The dominant nutrients limited types of reservoir bays were P limited (35%–47%) and N + P limited (35%–59%) at both stages, N limited situations less than 20% and generally appeared in storage period. Whatever the nutrients limited type was, phosphorus always had a higher effect on phytoplankton biomass. In N limited situation, nitrogen mainly from soil release (total effect = 0.6) and phosphorus from fertilizer (total effect = 0.22) and soil release (total effect = 0.17). In P limited situation, all three sources had almost high effects on nitrogen, phosphorus, and phytoplankton biomass. In N + P limited situation, the anthropogenic discharge was the main source of nutrients and the primary threaten factor for phytoplankton biomass. The approaches employed in this study could be generalized to the other basin and the results were significant to early warning and controlling water eutrophication.

scholarly journals Excessive application of chemical fertilizer and organophosphorus pesticides induced total phosphorus loss from planting causing surface water eutrophication

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Liyuan Liu ◽  
Xiangqun Zheng ◽  
Xiaocheng Wei ◽  
Zhang Kai ◽  
Yan Xu
Keyword(s):  
Surface Water ◽  
Total Phosphorus ◽  
Structural Equation ◽  
Organophosphorus Pesticides ◽  
Equation Model ◽  
Path Coefficient ◽  
Natural Conditions ◽  
Factors Affecting ◽  
Water Eutrophication ◽  
Anthropogenic Drivers

AbstractTotal phosphorus (TP) loss from planting was one of the resources causing agricultural non-point source pollution. It is significant to clarify the factors influencing TP loss, as well as explore the relationship between TP loss from planting and surface water eutrophication for making recommendations on the reduction of environmental pollution. In this study, the minimum and maximum of average TP loss was appeared in Qinghai and Shandong province with the TP loss of 7.7 × 102 t and 7.5 × 103 t from 2012 to 2014, respectively. The results of structural equation model (SEM) indicating that the effect of anthropogenic drivers on TP loss was more important than natural conditions due to the higher path coefficient of anthropogenic drivers (0.814) than that of natural conditions (0.130). For anthropogenic drivers, the path coefficients of usage of fertilizer and pesticides, which was often excessively applied in China, were 0.921 and 0.909, respectively causing they the two dominant factors affecting TP loss. Annual precipitation and relative humidity, which were belongs to natural conditions, increased TP loss by enhancing leaching and surface runoff. However, light duration could reduce TP loss by promoting crop growth and increasing TP absorption of crops, with a path coefficient of − 0.920. TP loss of each province in per unit area from planting was significantly correlated with TP concentration of its surface water (p < 0.05), suggesting that TP loss from planting was the main factor causing surface water eutrophication. This study targeted presented three proposals to reduce the TP loss from planting, including promotion of scientific fertilization technologies, restriction of organophosphorus pesticides, and popularization of water saving irrigation technologies. These findings as well as suggestions herein would provide direction for the reduction of TP loss from planting.

scholarly journals Exploring the Gender Gap in Young Adults' Attitudes about Animal Research

1996 ◽  
Vol 4 (1) ◽  
pp. 37-52 ◽  
Author(s):  
Linda K. Pifer
Keyword(s):  
Young Adults ◽  
Gender Gap ◽  
Scientific Literacy ◽  
Structural Equation ◽  
Science Achievement ◽  
Scientific Research ◽  
Equation Model ◽  
Animal Research ◽  
Total Effect ◽  
Feminist Attitudes

AbstractYoung adults' attitudes toward the use of animals in scientific research were examined by using data from the Longitudinal Study of American Youth (LSA Y). A structural equation model was estimated using LISREL8 to examine the development of these attitudes. Gender was found to have the greatest total effect on opposition to animal research, while feminist attitudes had the second greatest total effect. Feminist attitudes, 10th grade science achievement, adult scientific literacy, general attitudes toward science, partisan affiliation, anda numberof early home influences each explained part, but not all of the gender difference in attitudes about scientific research.

Application of Structural Equation Model for Exploring the influence of Environmental Factors on Phytoplankton in Bohai Bay

2011 ◽  
Vol 347-353 ◽  
pp. 1832-1835
Author(s):  
Xiao Fu Xu ◽  
Jian Hua Tao
Keyword(s):  
Structural Equation Model ◽  
Physical Environment ◽  
Phytoplankton Biomass ◽  
Structural Equation ◽  
Inorganic Nitrogen ◽  
Abiotic Factors ◽  
Equation Model ◽  
Bohai Bay ◽  
Dissolved Inorganic Nitrogen ◽  
Environment Temperature

In this paper, structural equation model (SEM) is used to explore the influence of coastal environment factors on phytoplankton in Bohai Bay. The SEM is a multivariate statistical method and by using it, a researcher can construct theoretical concepts, test their measurement reliability, hypothesize and evaluate of a network of relationships between variables. In our study, the hypothesized model considered the influence of the physical environment (temperature, salinity, and PH) and nitrogen (total dissolved inorganic nitrogen, total dissolved inorganic phosphate, and silicate) on total phytoplankton biomass. With the conclusions of this model, we find that nutrients have greater effect on phytoplankton biomass and there is a strong correlation between nutrients and physical environment. Additionally, salinity has greatest positive effect on phytoplankton, whereas total dissolved inorganic nitrogen has the greatest negative effect. Generally, the SEM gave plausible results and enabled the identification of the role of the abiotic factors on the phytoplankton.

scholarly journals BUDAYA ORGANISASI, INSENTIF, KEPUASAN KERJA, DAN KINERJA KARYAWAN PADA PT AVRIST ASSURANCE

2017 ◽  
Vol 19 (1) ◽  
pp. 74
Author(s):  
Iha Haryani Hatta ◽  
Widarto Rachbini
Keyword(s):  
Job Satisfaction ◽  
Organizational Culture ◽  
Structural Equation Model ◽  
Structural Equation ◽  
Employee Performance ◽  
Sampling Technique ◽  
Equation Model ◽  
Total Effect

Tujuan penelitian ini adalah untuk mengetahui pengaruh budaya organisasi dan insentif terhadap kepuasan kerja dan kinerja karyawan. Penelitian dilakukan di PT Avrist Assurance, dengan menggunakan 211 karyawan sebagai responden.Teknik pengambilan sampel dalam penelitian ini dilakukan secara acak sederhana. Analisis dilakukan dengan Structural Equation Model (SEM) menggunakan Lisrel 8.5. Hasil penelitian menemukan adanya pengaruh yang signifikan antarabudaya organisasi dan insentif terhadap kepuasan kerja dan kinerja karyawan, serta pengaruh yang signifikan antarakepuasan kerja terhadap kinerja karyawan. Pengaruh total budaya organisasi terhadap kepuasan kerja dan kinerja karyawan lebih dominan daripada pengaruh total insentif terhadap kepuasan kerja dankinerja karyawan.The purpose of this study was to determine the effect of organizational culture and incentive on job satisfaction and employees’ performance. The study was conducted in PT Avrist Assurance, using 211 employees as respondents. The sampling technique in this research is simple random. The analysis was performed with Structural Equation Model (SEM) using Lisrel 8.5. The study found that organizational culture and incentives significantly affect job satisfaction and employees’ performance. Moreover, job satisfaction significantly affect employees’ performance. The total effect of organizational culture on Job Satisfaction and employee performance is more dominant than the total effect of incentives on Job Satisfaction and employee performance.

Idiographic Dynamics of Positive Affect in GAD

2020 ◽  
Vol 36 (3) ◽  
pp. 500-509
Author(s):  
Hannah G. Bosley ◽  
Devon B. Sandel ◽  
Aaron J. Fisher
Keyword(s):  
Positive Affect ◽  
Structural Equation ◽  
Alternative Hypothesis ◽  
Equation Model ◽  
Aggregated Data ◽  
Regulatory Strategy ◽  
Constant State ◽  
Automatic Search ◽  
Time Lagged ◽  
Exploratory Procedure

Abstract. Generalized anxiety disorder (GAD) is associated with worry and emotion regulation difficulties. The contrast-avoidance model suggests that individuals with GAD use worry to regulate emotion: by worrying, they maintain a constant state of negative affect (NA), avoiding a feared sudden shift into NA. We tested an extension of this model to positive affect (PA). During a week-long ecological momentary assessment (EMA) period, 96 undergraduates with a GAD analog provided four daily measurements of worry, dampening (i.e., PA suppression), and PA. We hypothesized a time-lagged mediation relationship in which higher worry predicts later dampening, and dampening predicts subsequently lower PA. A lag-2 structural equation model was fit to the group-aggregated data and to each individual time-series to test this hypothesis. Although worry and PA were negatively correlated in 87 participants, our model was not supported at the nomothetic level. However, idiographically, our model was well-fit for about a third (38.5%) of participants. We then used automatic search as an idiographic exploratory procedure to detect other time-lagged relationships between these constructs. While 46 individuals exhibited some cross-lagged relationships, no clear pattern emerged across participants. An alternative hypothesis about the speed of the relationship between variables is discussed using contemporaneous correlations of worry, dampening, and PA. Findings suggest heterogeneity in the function of worry as a regulatory strategy, and the importance of temporal scale for detection of time-lagged effects.

Differential Item Functioning in Brief Instruments of Disordered Eating

2019 ◽  
Vol 35 (6) ◽  
pp. 823-833 ◽  
Author(s):  
Desiree Thielemann ◽  
Felicitas Richter ◽  
Bernd Strauss ◽  
Elmar Braehler ◽  
Uwe Altmann ◽  
...  
Keyword(s):  
Differential Item Functioning ◽  
Disordered Eating ◽  
Structural Equation ◽  
Young Female ◽  
Eating Attitudes ◽  
Equation Model ◽  
German Population ◽  
Test Fairness ◽  
Item Functioning ◽  
Multiple Indicator

Abstract. Most instruments for the assessment of disordered eating were developed and validated in young female samples. However, they are often used in heterogeneous general population samples. Therefore, brief instruments of disordered eating should assess the severity of disordered eating equally well between individuals with different gender, age, body mass index (BMI), and socioeconomic status (SES). Differential item functioning (DIF) of two brief instruments of disordered eating (SCOFF, Eating Attitudes Test [EAT-8]) was modeled in a representative sample of the German population ( N = 2,527) using a multigroup item response theory (IRT) and a multiple-indicator multiple-cause (MIMIC) structural equation model (SEM) approach. No DIF by age was found in both questionnaires. Three items of the EAT-8 showed DIF across gender, indicating that females are more likely to agree than males, given the same severity of disordered eating. One item of the EAT-8 revealed slight DIF by BMI. DIF with respect to the SCOFF seemed to be negligible. Both questionnaires are equally fair across people with different age and SES. The DIF by gender that we found with respect to the EAT-8 as screening instrument may be also reflected in the use of different cutoff values for men and women. In general, both brief instruments assessing disordered eating revealed their strengths and limitations concerning test fairness for different groups.

The Influence of Cognitive and Affective Reactions to Feedback on Subsequent Goals

2010 ◽  
Vol 15 (2) ◽  
pp. 121-131 ◽  
Author(s):  
Remus Ilies ◽  
Timothy A. Judge ◽  
David T. Wagner
Keyword(s):  
Performance Feedback ◽  
Business School ◽  
Structural Equation ◽  
Emotional Reactions ◽  
Equation Model ◽  
Proposed Model ◽  
And Performance ◽  
Dispositional Measure ◽  
The Relationship ◽  
Reactions To Feedback

This paper focuses on explaining how individuals set goals on multiple performance episodes, in the context of performance feedback comparing their performance on each episode with their respective goal. The proposed model was tested through a longitudinal study of 493 university students’ actual goals and performance on business school exams. Results of a structural equation model supported the proposed conceptual model in which self-efficacy and emotional reactions to feedback mediate the relationship between feedback and subsequent goals. In addition, as expected, participants’ standing on a dispositional measure of behavioral inhibition influenced the strength of their emotional reactions to negative feedback.

Forced Zero Cross-Loading Misspecifications in Measurement Component of Structural Equation Models

Methodology ◽  
2014 ◽  
Vol 10 (4) ◽  
pp. 138-152 ◽  
Author(s):  
Hsien-Yuan Hsu ◽  
Susan Troncoso Skidmore ◽  
Yan Li ◽  
Bruce Thompson
Keyword(s):  
Structural Equation ◽  
Structural Model ◽  
Structural Equation Models ◽  
Equation Model ◽  
Model Fit ◽  
Model Specification ◽  
Simulation Design ◽  
Measurement Models ◽  
Fit Statistics ◽  
Path Coefficients

The purpose of the present paper was to evaluate the effect of constraining near-zero parameter cross-loadings to zero in the measurement component of a structural equation model. A Monte Carlo 3 × 5 × 2 simulation design was conducted (i.e., sample sizes of 200, 600, and 1,000; parameter cross-loadings of 0.07, 0.10, 0.13, 0.16, and 0.19 misspecified to be zero; and parameter path coefficients in the structural model of either 0.50 or 0.70). Results indicated that factor pattern coefficients and factor covariances were overestimated in measurement models when near-zero parameter cross-loadings constrained to zero were higher than 0.13 in the population. Moreover, the path coefficients between factors were misestimated when the near-zero parameter cross-loadings constrained to zero were noteworthy. Our results add to the literature detailing the importance of testing individual model specification decisions, and not simply evaluating omnibus model fit statistics.

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