Design Equations for Bod Removal in Facultative Ponds

1987 ◽  
Vol 19 (12) ◽  
pp. 187-193 ◽  
Author(s):  
E. Joe Middlebrooks
Keyword(s):  
Environmental Protection Agency ◽  
Linear Models ◽  
Plug Flow ◽  
Empirical Models ◽  
The Us ◽  
Non Linear ◽  
The Usa ◽  
Using Data ◽  
Removal Model ◽  
Best Fit

Facultative pond performance data collected for the US Environmental Protection Agency (USEPA) at four locations throughout the USA and data collected by others were used to evaluate the most frequently used design equations and to develop non-linear design equations. Empirical models were evaluated as well as the classical plug flow and complete mix models. The first order plug flow model gave the best fit of all the rational models. The empirical non-linear models did not fit the data, nor did the other empirical models with the exception being the areal loading and removal model. Attempts to verify the models developed with the USEPA data using data collected by others were not successful with the exception of the areal loading and removal model.

scholarly journals HETEROGENEITY IN PROGRESSION OF COGNITIVE IMPAIRMENT AND VARIATIONS IN HEALTH EXPENDITURES AND HEALTH SERVICES USE

2019 ◽  
Vol 3 (Supplement_1) ◽  
pp. S126-S126
Author(s):  
Wassim Tarraf ◽  
Hector M González
Keyword(s):  
Nursing Home ◽  
Cognitive Impairment ◽  
Cognitive Aging ◽  
Linear Models ◽  
Health Issues ◽  
Health Services Use ◽  
The Us ◽  
Inpatient Hospitalizations ◽  
Baseline Probability ◽  
Using Data

Abstract Cognitive aging and disease (e.g. dementia) are leading public health issues as longevity increases and the US population ages. We fit generalized linear models using data from the longitudinal Health and Retirement Study (2008-2014) on (Unweighted N=1,884) participants 70-years and older who met criteria for cognitive impairment not dementia (CIND), based on Aging, Demographics, and Memory Study specification, at baseline (2008) to test how impairment reversion, stability, and transition to dementia over 8-years affect change in biennial hospitalizations, nursing-home use, and out-of-pocket expenditures (OOP). Over 8-years, 13% reverted to normal cognition, 20% remained as CIND, 21% transitioned to dementia, and 46% died. In these groups, average OOP spending at baseline was $2311 (SE=$225), $2722 (SE=$278), $2180 (SE=$228), and $3653 (SE=$322), respectively. Average OOP spending increased to $3,095, $4,720, and $11,548 by the 8th year for those that reverted, stayed stable, and transitioned, respectively. Average OOP spending at the wave preceding death was $11,600. We observed substantial increases in nursing home use that were particularly pronounced among those that transitioned to dementia (Baseline Probability=0.04 increasing to 0.37 over 8-years) or died (0.09 increasing to 0.35 over 6-years), and similar but less pronounced differences in patterns of inpatient hospitalizations. Estimates were only slightly modified through adjustments to sociodemographic characteristics and comorbid conditions. We discuss how healthcare policy and clinical interventions focusing on early identification of impairment can potentially lead to improved and more efficient healthcare if better understanding of heterogeneities in impairment and cognitive disease progression is achieved.

Competition and competitiveness in the US airline industry

2015 ◽  
Vol 25 (2) ◽  
pp. 134-155 ◽  
Author(s):  
T.J. Hannigan ◽  
Robert D. Hamilton III ◽  
Ram Mudambi
Keyword(s):  
Airline Industry ◽  
Negative Relationship ◽  
Operational Efficiency ◽  
Resource Heterogeneity ◽  
Content Type ◽  
Firm Strategies ◽  
The Us ◽  
The Usa ◽  
Using Data ◽  
Core Capabilities

Purpose – This study aims to employ a resource-based lens to explore the competitive implications of firm strategies under conditions of market commonality and shared resource pools. Design/methodology/approach – The firms’ core capabilities in these environments may focus on operational efficiency, as firms seek to compete under significant resource heterogeneity constraints. Findings – Using data from the USA airline industry from 1996-2011, we find that price has a positive relationship with firm performance, whereas quality has a negative relationship. Operational efficiency is a driver of both strategies. Research limitations/implications – The study uses US data. Extending the findings to the global setting may require recognizing other competitive dimensions. Originality/value – Firms that focus on non-core activities perform less well. The results offer insights into an industry that has interested strategy researchers for many years and may suggest an application to other industries with similar characteristics.

Considering online consumer reviews to predict movie box-office performance between the years 2009 and 2014 in the US

2018 ◽  
Vol 36 (6) ◽  
pp. 1010-1026 ◽  
Author(s):  
Ya-Han Hu ◽  
Wen-Ming Shiau ◽  
Sheng-Pao Shih ◽  
Cho-Ju Chen
Keyword(s):  
Support Vector ◽  
Related Factors ◽  
Content Type ◽  
Box Office ◽  
Performance Predictions ◽  
The Us ◽  
The Usa ◽  
Using Data ◽  
The One ◽  
Box Office Performance

Purpose The purpose of this paper is to combine basic movie information factors, external factors and review factors, to predict box-office performance and identify the most crucial factor of influence for box-office performance. Design/methodology/approach Five movie genres and first-week movie reviews found on IMDb were collected. The movie reviews were quantified using sentiment analysis tools SentiStrength and Stanford CoreNLP, in which quantified data were combined with basic movie information and external environment factors to predict movie box-office performance. A movie box-office performance prediction model was then developed using data mining (DM) technologies with M5 model trees (M5P), linear regression (LR) and support vector regression (SVR), after which movie box-office performance predictions were made. Findings The results of this paper showed that the inclusion of movie reviews generated more accurate prediction results. Concerning movie review-related factors, the one that exhibited the greatest effect on box-office performance was the number of movie reviews made, whereas movie review content only displayed an effect on box-office performance for specific movie genres. Research limitations/implications Because this paper collected movie data from the IMDb, the data were limited and primarily consisted of movies released in the USA; data pertaining to less popular movies or those released outside of the USA were, thus, insufficient. Practical implications This paper helps to verify whether the consideration of the features extracted from movie reviews can improve the performance of movie box-office. Originality/value Through various DM technologies, this paper shows that movie reviews enhanced the accuracy of box-office performance predictions and the content of movie reviews has an effect on box-office performance.

Paper 15. Some Aspects of Prediction and Simulation of Manoeuvres

1972 ◽  
Vol 14 (7) ◽  
pp. 108-114
Author(s):  
G. van Leeuwen
Keyword(s):  
Mathematical Models ◽  
Linear Models ◽  
Empirical Models ◽  
Model Tests ◽  
Full Scale ◽  
Non Linear ◽  
Free Running ◽  
Horizontal Oscillation ◽  
Prediction And Simulation

Prediction and simulation are dependent on the knowledge gained from mathematical models. The choice and the form of the model is determined by the specific application and the accuracy required. Model techniques, such as horizontal oscillation tests, provide the means of finding the coefficients of extensive non-linear models, though for other purposes, such as simulation, there is also a need for simpler, empirical models. To determine the coefficients of such models, free-running full-scale or model tests are necessary.

Revisiting the role of dissimilarity of host communities in driving dissimilarity of ectoparasite assemblages: non-linear vs linear approach

Parasitology ◽  
2017 ◽  
Vol 144 (10) ◽  
pp. 1365-1374 ◽  
Author(s):  
LUTHER VAN DER MESCHT ◽  
IRINA S. KHOKHLOVA ◽  
ELIZABETH M. WARBURTON ◽  
BORIS R. KRASNOV
Keyword(s):  
Linear Models ◽  
Species Turnover ◽  
Geographic Distance ◽  
Parasite Community ◽  
Model Fit ◽  
Linear Approach ◽  
Non Linear ◽  
Using Data ◽  
Better Than

SUMMARYWe revisited the role of dissimilarity of host assemblages in shaping dissimilarity of flea assemblages using a non-linear approach. Generalized dissimilarity models (GDMs) were applied using data from regional surveys of fleas parasitic on small mammals in four biogeographical realms. We compared (1) model fit, (2) the relative effects of host compositional and phylogenetic turnover and geographic distance on flea compositional and phylogenetic turnover, and (3) the rate of flea turnover along gradients of host turnover and geographic distance with those from earlier application of a linear approach. GDMs outperformed linear models in explaining variation in flea species turnover and host dissimilarity was the best predictor of flea dissimilarity, irrespective of scale. The shape of the relationships between flea compositional turnovers along host compositional turnover was similar in all realms, whereas turnover along geographic distance differed among realms. In contrast, the rate of flea phylogenetic turnover along gradients of host phylogenetic turnover differed among realms, whereas flea phylogenetic turnover did not depend on geographic distance in any realm. We demonstrated that a non-linear approach (a) explained spatial variation in parasite community composition better than and (b) revealed patterns that were obscured by earlier linear analyses.

Do higher financial returns lead to better environmental performance in North America’s forest products sector?

2008 ◽  
Vol 38 (9) ◽  
pp. 2515-2525 ◽  
Author(s):  
Jesse Yamaguchi ◽  
G. Cornelis van Kooten
Keyword(s):  
Environmental Protection Agency ◽  
Environmental Performance ◽  
Negative Relationship ◽  
Forest Products ◽  
Financial Economic ◽  
Kuznets Curve ◽  
Firm Level ◽  
Level Data ◽  
The Us ◽  
Using Data

This study examines the relation between corporate environmental performance and corporate financial (economic) performance in North America’s forest products industry to determine whether there is a firm-level environmental Kuznets curve (EKC). An unbalanced panel of firm-level observations is constructed using data from PricewaterhouseCoopers, the US Environmental Protection Agency, and Environment Canada. The analysis focuses on methanol and formaldehyde emissions because these are the only pollutants for which consistent firm-level data are available in forestry. We find strong evidence of a firm-level EKC. The evidence is considerably weaker if endogeneity related to the effect of past pollution on current pollution or endogeneity resulting from a possible circular relationship between rate of return and pollution is taken into account, although the available time horizon is too short to conclude that endogeneity is a problem. Even so, there remains evidence of a negative relationship between financial performance and environmental performance for formaldehyde.

scholarly journals SKEW AND IMPLIED LEVERAGE EFFECT: SMILE DYNAMICS REVISITED

2015 ◽  
Vol 18 (04) ◽  
pp. 1550022 ◽  
Author(s):  
VINCENT VARGAS ◽  
TUNG-LAM DAO ◽  
JEAN-PHILIPPE BOUCHAUD
Keyword(s):  
Linear Models ◽  
Garch Model ◽  
Leverage Effect ◽  
Option Markets ◽  
Empirical Results ◽  
Price Series ◽  
Non Linear ◽  
Asymmetric Garch ◽  
Linear Effects ◽  
Using Data

We revisit the "Smile Dynamics" problem, which consists in relating the implied leverage (i.e. the correlation of the at-the-money volatility with the returns of the underlying) and the skew of the option smile. The ratio between these two quantities, called "Skew-Stickiness Ratio" (SSR) by Bergomi (2009), saturates to the value 2 for linear models in the limit of small maturities, and converges to 1 for long maturities. We show that for more general, non-linear models (such as the asymmetric GARCH model), Bergomi's result must be modified, and can be larger than 2 for small maturities. The discrepancy comes from the fact that the volatility skew is, in general, different from the skewness of the underlying. We compare our theory with empirical results, using data both from option markets and from the underlying price series, for the S&P 500 and the DAX. We find, among other things, that although both the implied leverage and the skew appear to be too strong on option markets, their ratio is well explained by the theory. We observe that the SSR indeed becomes larger than 2 for small maturities, signalling the presence of non-linear effects.

scholarly journals Estimation of annual compound growth rates of guava (Psidium guajava L.) fruit in Haryana using Non linear model

2019 ◽  
Vol 11 (4) ◽  
pp. 778-784
Author(s):  
Pardeep Panghal ◽  
Manoj Kumar ◽  
Sarita Rani
Keyword(s):  
Growth Rate ◽  
Linear Model ◽  
Growth Rates ◽  
Logistic Model ◽  
Linear Models ◽  
Psidium Guajava ◽  
Annual Growth Rate ◽  
Guava Fruit ◽  
Non Linear ◽  
Best Fit

Computation of growth rates plays an important role in agricultural and economic research to study growth pattern of a various commodities. Many of the research workers used the parametric approach for computation of annual growth rate but not use the concept of non-linear model.  In this paper, an attempt has been made to study growth rates of guava for three districts (Hisar, and Kurukshetra) and Haryana state as a whole using different non-linear models. The time series data on annual area and production of guava (Psidium guajava L.) in different districts of Haryana from 1990-91 to 2015-16 were collected to fit non linear models. Growth rates were computed through best fitted non-linear models. It was found that Logistic model could be best fit for computation of growth rates of area for guava fruit in Hisar and Kurukshetra district and Haryana state as a whole whereas Gompertz model was best fit for Yamunanagar district based on high R2 and least MSE and RMSE values. It was also observed that monomolecular model was best fit for production of guava fruits in Hisar and Yamunanagar district whereas Logistic model was best fit for production of guava fruit in Kurukshetra and Haryana state as a whole because of high R2 and least MSE and RMSE values. R and excel software have been used for fitting the non linear model and computation of growth rates for area and production of guava fruit for the year 1990-91 to 2015-16. None has been used the non linear model growth model for computation of annual growth rate of guava fruit for area and production of Haryana state. But in this work non linear growth model has been used for computation of growth rate instead of parametric approaches.

scholarly journals Are African Stock Markets Inefficient or Adaptive? Empirical Literature

2020 ◽  
Author(s):  
Adefemi A. Obalade ◽  
Paul-Francois Muzindutsi
Keyword(s):  
Stock Returns ◽  
Stock Markets ◽  
Linear Models ◽  
Empirical Studies ◽  
Weak Form ◽  
Empirical Literature ◽  
Recent Theory ◽  
Non Linear ◽  
Best Fit ◽  
Weak Form Efficiency

This chapter reviews empirical studies on weak form of efficiency with the aim of establishing whether the African market is inefficient or adaptive. The reviewed studies are categorised based on their methodological approaches to compare the power of linear and non-linear models in testing for weak-form efficiency. The studies on calendar anomalies, an indication of weak-form inefficiency, are reviewed to assess whether these anomalies are adaptive as portrayed by the relatively recent theory of adaptive market hypothesis (AMH). The scope of reviewed studies is also extended to developed and emerging markets to gain a broad comparison of the findings. This review revealed that non-linear dependence has been revealed in stock returns suggesting that non-linear models are best fit to test for the stock market efficiency. Reviewed studies produced contradictory findings with some supporting and others rejecting weak-form efficiency. Thus, most studies support the AMH, which suggests that market efficiencies and anomalies are time changing. This chapter concludes that most of the existing studies on AMH have been carried out in markets other than Africa, and hence, further empirical studies on the evolving and changing nature of efficiency in African stock markets are recommended.

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