Predictive Models of Benthic Macroinvertebrate Density for Use in Instream Flow Studies and Regulated Flow Management

1981 ◽  
Vol 38 (11) ◽  
pp. 1363-1370 ◽  
Author(s):  
James A. Gore ◽  
Robert D. Judy Jr.
Keyword(s):  
Habitat Suitability ◽  
High Reliability ◽  
Cross Product ◽  
Physical Habitat ◽  
Exponential Polynomial ◽  
Flow Management ◽  
Stream Management ◽  
Product Term ◽  
Channel Hydraulics ◽  
Sport Fish

As an adjunct to the U.S. Fish and Wildlife Service incremental method for determining habitat suitability for sport fish species at various discharge levels, we propose a similar method for determining optimum conditions for stream macroinvertebrates that stresses predictions of density maxima and flow predictions for maintenance of suitable lotic habitat.The curve fitting equations of the computer simulation showed high reliability in predicting physical habitat tolerances of selected aquatic insects. An example using Nectopsyche lahontonensis is presented.The new predictive model, by exponential polynomial analysis, answers criticisms of earlier models which do not include the dependence of velocity and depth in stream channel hydraulics. The added cross-product term in the model altered the predicted peak responses (density) with random changes in depth and velocity. Although the new model improves the predictions, its effectiveness in stream management has yet to be tested.Key words: habitat suitability, macroinvertebrates, exponential polynomial analysis, flow management, Nectopsyche lahontonensis

scholarly journals Ultimate Bound of a 3D Chaotic System and Its Application in Chaos Synchronization

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Jiezhi Wang ◽  
Qing Zhang ◽  
Zengqiang Chen ◽  
Hang Li
Keyword(s):  
Chaotic System ◽  
Chaos Synchronization ◽  
Three Dimensional ◽  
Boundary Region ◽  
Cross Product ◽  
State Equation ◽  
Linear Coefficient ◽  
Analytical Expression ◽  
Product Term ◽  
Cross Product Term

Two ellipsoidal ultimate boundary regions of a special three-dimensional (3D) chaotic system are proposed. To this chaotic system, the linear coefficient of theith state variable in theith state equation has the same sign; it also has two one-order terms and one quadratic cross-product term in each equation. A numerical solution and an analytical expression of the ultimate bounds are received. To get the analytical expression of the ultimate boundary region, a new result of one maximum optimization question is proved. The corresponding ultimate boundary regions are demonstrated through numerical simulations. Utilizing the bounds obtained, a linear controller is proposed to achieve the complete chaos synchronization. Numerical simulation exhibits the feasibility of the designed scheme.

scholarly journals A Novel Three Dimension Autonomous Chaotic System with a Quadratic Exponential Nonlinear Term

2012 ◽  
Vol 2 (2) ◽  
pp. 209-215 ◽  
Author(s):  
F. Yu ◽  
C. Wang
Keyword(s):  
Chaotic System ◽  
Nonlinear Term ◽  
Cross Product ◽  
Three Dimension ◽  
Compound Structure ◽  
Compensation Circuit ◽  
Forming Mechanism ◽  
Product Term ◽  
Practical Engineering ◽  
Cross Product Term

A novel three dimension autonomous (3D) chaotic system with a quadratic exponential nonlinear term and a quadratic cross-product term is described in this paper. The basic dynamical properties of the new attractor are studied. The forming mechanism of its compound structure, obtained by merging together two simple attractors after performing one mirror operation, has been investigated by detailed numerical as well as theoretical analysis. Finally, the exponential operation circuit and its temperature-compensation circuit, which makes the new system more applicable from a practical engineering perspective, are investigated.

scholarly journals Empirical Validation of MesoHABSIM Models Developed with Different Habitat Suitability Criteria for Bullhead Cottus Gobio L. as an Indicator Species

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 726 ◽  
Author(s):  
Mikołaj Adamczyk ◽  
Piotr Parasiewicz ◽  
Paolo Vezza ◽  
Paweł Prus ◽  
Giovanni De Cesare
Keyword(s):  
Habitat Suitability ◽  
Model Comparison ◽  
Expert Knowledge ◽  
General Information ◽  
Model Verification ◽  
Physical Habitat ◽  
Riverine Ecosystems ◽  
Cottus Gobio ◽  
Species Specific ◽  
Water Management Planning

Application of instream habitat models such as the Mesohabitat Simulation Model (MesoHABSIM) is becoming increasingly popular. Such models can predict alteration to a river physical habitat caused by hydropower operation or river training. They are a tool for water management planning, especially in terms of requirements of the Water Framework Directive. Therefore, model verification studies, which investigate the accuracy and reliability of the results generated, are essential. An electrofishing survey was conducted in September 2014 on the Stura di Demonte River located in north-western Italy. One hundred and sixteen bullhead—Cottus gobio L.—were captured in 80 pre-exposed area electrofishing (PAE) grids. Observations of bullhead distribution in various habitats were used to validate MesoHABSIM model predictions created with inductive and deductive habitat suitability indices. The inductive statistical models used electrofishing data obtained from multiple mountainous streams, analyzed with logistic regression. The deductive approach was based on conditional habitat suitability criteria (CHSC) derived from expert knowledge and information gathered from the literature about species behaviour and habitat use. The results of model comparison and validation show that although the inductive models are more precise and reflect site- and species-specific characteristics, the CHSC model provides quite similar results. We propose to use inductive models for detailed planning of measures that could potentially impair riverine ecosystems at a local scale, since the CHSC model provides general information about habitat suitability and use of such models is advised in pre-development or generic scale studies. However, the CHSC model can be further calibrated with localized electrofishing data at a lower cost than development of an inductive model.

Dynamic conditional betas and equity returns

2020 ◽  
Vol 07 (04) ◽  
pp. 2050035
Author(s):  
Salvatore Joseph Terregrossa ◽  
Veysel Eraslan
Keyword(s):  
Cross Product ◽  
Equity Returns ◽  
Excess Return ◽  
Cross Sectional ◽  
New Approach ◽  
Product Term ◽  
Conditional Beta ◽  
Conditional Betas ◽  
Empirical Methodology ◽  
Cross Product Term

Our study makes use of a new approach to estimate time-varyingbetas with an application of the corrected Dynamic Conditional Correlation (cDCC) model. Our empirical methodology encompasses an examination of predictive relations between equity return and different specifications of dynamic conditional beta, using cross-sectional regression analysis at both the portfolio and firm levels. Our main finding is a significant, positive relation between equity excess return and an interactive cross product term of dynamic conditional beta and market excess return ([Formula: see text]); suggesting that equity return is largely determined by an interaction effect between dynamic beta and market return.

scholarly journals Does SLE widen or narrow race/ethnic disparities in the risk of five co-morbid conditions? Evidence from a community-based outpatient care system

Lupus ◽  
2019 ◽  
Vol 28 (14) ◽  
pp. 1619-1627 ◽  
Author(s):  
T Falasinnu ◽  
Y Chaichian ◽  
J Li ◽  
S Chung ◽  
B E Waitzfelder ◽  
...  
Keyword(s):  
Lupus Erythematosus ◽  
Minority Groups ◽  
Ethnic Disparities ◽  
Cross Product ◽  
Outpatient Setting ◽  
Secondary Complications ◽  
Community Based ◽  
Product Term ◽  
Racial Ethnic ◽  
Cross Product Term

Objective The heterogeneous spectrum of systemic lupus erythematosus (SLE) often presents with secondary complications such as cardiovascular disease (CVD), infections and neoplasms. Our study assessed whether the presence of SLE independently increases or reduces the disparities, accounting for the already higher risk of these outcomes among racial/ethnic minority groups without SLE. Methods We defined a cohort using electronic health records data (2005–2016) from a mixed-payer community-based outpatient setting in California serving patients of diverse racial/ethnic backgrounds. The eligible population included adult patients with SLE and matched non-SLE patients (≥18 years old). SLE was the primary exposure. The following outcomes were identified: pneumonia, other infections, CVD and neoplasms. For each racial/ethnic group, we calculated the proportion of incident co-morbidities by SLE exposure, followed by logistic regression for each outcome with SLE as the exposure. We evaluated interaction on the additive and multiplicative scales by calculating the relative excess risk due to interaction and estimating the cross-product term in each model. Results We identified 1036 SLE cases and 8875 controls. The incidence for all outcomes was higher among the SLE exposed. We found little difference in the odds of the outcomes associated with SLE across racial/ethnic groups, even after multivariable adjustment. This finding was consistent on the multiplicative and additive scales. Conclusion We demonstrated that SLE status does not independently confer substantial interaction or heterogeneity by race/ethnicity toward the risk of pneumonia, other infections, CVD or neoplasms. Further studies in larger datasets are necessary to validate this novel finding.

scholarly journals Application of the physical habitat simulation for fish species to assess environmental flows in an Atlantic Forest Stream in South-eastern Brazil

2015 ◽  
Vol 13 (4) ◽  
pp. 685-698 ◽  
Author(s):  
Marcus Rodrigues da Costa ◽  
Tailan Moretti Mattos ◽  
Victor Hugo Fernandes ◽  
Francisco Martínez-Capel ◽  
Rafael Muñoz-Mas ◽  
...  
Keyword(s):  
Atlantic Forest ◽  
Fish Species ◽  
Habitat Suitability ◽  
Environmental Flows ◽  
Southeastern Brazil ◽  
Microhabitat Use ◽  
Physical Habitat ◽  
Forest Stream ◽  
Habitat Simulation ◽  
Target Fish

ABSTRACT The physical habitat simulation sub-routine of the Instream Flow Incremental Methodology (IFIM) uses hydraulic modeling and suitability indices of target fish species to predict how differences in-stream flows affect the microhabitat occupation by fish species. This habitat modelling approach was adopted to assess the ecological effects of running flows on three neotropical fish species of different orders (Bryconamericus ornaticeps , Ancistrus multispinis and Geophagus brasiliensis ).The study encompassed two reaches of an Atlantic Forest stream in Southeastern Brazil where topographic and hydraulic (depth, velocity and type of substrate) characteristics were measured to implement one-dimensional hydraulic simulation. Sub aquatic observation of fish was performed to collect data on microhabitat use and these data were used to develop habitat suitability curves that were used in the habitat simulation to obtain the habitat suitability index (HSI) and weighted usable area (WUA) versus flow curves. Upon these curves minimum and optimum environmental flows for the target fish species were proposed. Bryconamericus ornaticeps and A. multispinis selected microhabitats around 0.6 m depth, whereas G. brasiliensis showed a wider suitable range (0.35-0.9 m). All the three species were mainly observed in microhabitat with low flow velocity (0.1 m/s). Bryconamericus ornaticeps selected more frequently coarse substrate (e.g. boulders) but it appeared also over sandy substrate, whereas A. multispinis and G. brasiliensis selected preferably boulders. The range of 0.65-0.85 m3/s was found as the optimum to meet the needs of the three fish species. Our results agree with the necessary objective information to perform grounded management actions in the frame of a management program aiming at ecosystem conservation. Thereby it can be considered a successful pilot study in environmental flow assessment in an Atlantic Forest stream of Brazil.

THE GENERATION AND ANALYSIS OF A NEW FOUR-DIMENSIONAL HYPERCHAOTIC SYSTEM

2007 ◽  
Vol 18 (06) ◽  
pp. 1013-1024 ◽  
Author(s):  
JIEZHI WANG ◽  
ZENGQIANG CHEN ◽  
ZHUZHI YUAN
Keyword(s):  
Lyapunov Exponent ◽  
Cross Product ◽  
Phase Portraits ◽  
Hyperchaotic System ◽  
Bifurcation Diagrams ◽  
Dynamic Behaviors ◽  
System Parameters ◽  
Product Term ◽  
Two Parameters ◽  
Cross Product Term

A new four-dimensional continuous autonomous hyperchaotic system is considered. It possesses two parameters, and each equation of it has one quadratic cross product term. Some basic properties of it are studied. The dynamic behaviors of it are analyzed by the Lyapunov exponent (LE) spectrum, bifurcation diagrams, phase portraits, and Poincaré sections. The system has larger hyperchaotic region. When it is hyperchaotic, the two positive LE are both large and they are both larger than 1 if the system parameters are taken appropriately.

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