A model approach to the population dynamics of the rotifer Brachionus rubens in two-stage chemostat culture

Oecologia ◽  
1985 ◽  
Vol 65 (2) ◽  
pp. 252-259 ◽  
Author(s):  
Karl Otto Rothhaupt
Keyword(s):  
Population Dynamics ◽  
Chemostat Culture ◽  
Two Stage ◽  
Brachionus Rubens ◽  
Model Approach

Modeling population dynamics and nonstationary processes of difficult-to-age fishery species with a hierarchical Bayesian two-stage model

2019 ◽  
Vol 76 (12) ◽  
pp. 2199-2214 ◽  
Author(s):  
Yan Li ◽  
Laura M. Lee ◽  
Jason Rock
Keyword(s):  
North Carolina ◽  
Population Dynamics ◽  
Natural Mortality ◽  
Hierarchical Bayesian ◽  
Stage Model ◽  
Survey Analysis ◽  
Two Stage ◽  
The North ◽  
Fishery Species

Modeling population dynamics and establishing a comprehensive population assessment for fishery species that are difficult to age have been challenging. Determination of age for such species is still an unresolved issue or is at best uncertain. Catch-survey analysis does not require full age information but can still provide a comprehensive population assessment. It was extended to incorporate multiple surveys and multiple sources of uncertainties within the statistical catch-at-age framework in the applications to crustaceans. Here, we further generalize and extend the multiple survey catch-survey analysis into a hierarchical Bayesian two-stage model by applying the hierarchical Bayesian approach. The hierarchical Bayesian approach can sufficiently incorporate uncertainty and expert opinions in parameter estimation. We developed a series of models with different assumptions for natural mortality and catchability, including nonstationary (i.e., time-varying) assumptions. We evaluated model robustness to these assumptions and compared population dynamics estimates and population status determination. We demonstrated the application of the hierarchical Bayesian two-stage model using the North Carolina blue crab (Callinectes sapidus) example. In this example, estimation of population size and fishing mortality and determination of population status were robust to the natural mortality and catchability assumptions. The North Carolina blue crab population is less likely to have nonstationary catchability or nonstationary natural mortality. Its natural mortality is more likely to vary by stage than by sex or over time.

Population dynamics of a two-stage species with recruitment

2012 ◽  
Vol 36 (6) ◽  
pp. 722-729 ◽  
Author(s):  
Lilia M. Ladino ◽  
Jose C. Valverde
Keyword(s):  
Population Dynamics ◽  
Two Stage

A two-stage mixed-effects model approach for gene-set analyses in candidate gene studies

2011 ◽  
Vol 31 (11-12) ◽  
pp. 1190-1202 ◽  
Author(s):  
Roula Tsonaka ◽  
Annette H. M. van der Helm-van Mil ◽  
Jeanine J. Houwing-Duistermaat
Keyword(s):  
Candidate Gene ◽  
Mixed Effects ◽  
Mixed Effects Model ◽  
Two Stage ◽  
Gene Set ◽  
Candidate Gene Studies ◽  
Model Approach

Population dynamics of the cactus Mammillaria gaumeri: an integral projection model approach

2012 ◽  
Vol 54 (2) ◽  
pp. 321-334 ◽  
Author(s):  
Merari Esther Ferrer-Cervantes ◽  
Martha Elena Méndez-González ◽  
Pedro-Francisco Quintana-Ascencio ◽  
Alfredo Dorantes ◽  
Gabriel Dzib ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Integral Projection Model ◽  
Projection Model ◽  
Integral Projection ◽  
Model Approach

scholarly journals SIMULASI PERUBAHAN SOSIO-EKONOMI SERTA STRATEGI RUMAHTANGGA NELAYAN SKALA KECIL DALAM MEMPERTAHANKAN EKONOMI DAN KETAHANAN PANGAN RUMAHTANGGA DI PEDESAAN PANTAI JAWA TIMUR

2017 ◽  
Vol 5 (2) ◽  
pp. 183
Author(s):  
Pudji Purwanti
Keyword(s):  
Food Security ◽  
Simulation Model ◽  
Least Squares ◽  
Small Scale ◽  
Operational Cost ◽  
Two Stage ◽  
Fuel Price ◽  
Simulation Results ◽  
Two Stage Least Squares ◽  
Model Approach

Penelitian bertujuan untuk menganalisa dampak perubahan parameter ekonomi seperti kenaikan BBM, kenaikan harga kebutuhan pokok, dan strategi rumahtangga dalam meningkatkan pendapatan melalui penambahan curahan kerja non perikanan. Penelitian ini menggunakan model simulasi dengan metode Two Stage Least Squares (2SLS) untuk menganalisa perubahan ekonomi dan ketahanan pangan rumah tangga nelayan di Kabupaten Pasuruan dan Trenggalek, Provinsi Jawa Timur. Hasil simulasi menunjukkan bahwa kenaikan sebesar 30 % untuk biaya operasional melaut dan harga bahan pokok pangan harus diimbangi dengan meningkatnya curahan kerja suami dan istri masing-masing 15%. Kenaikan tersebut juga menyebabkan penurunan ketahanan pangan rumah tangga nelayan. Hasil penelitian menyimpulkan rumahtanga nelayan skala kecil dapat mempertahankan ketahanan pangannya dengan memanfaatkan waktu kerja di rumah dan senggang istri nelayan sebagai waktu produktif berorientasi pasar. Tittle: Simulation of Socio-economic and Strategies of Small-scale Fisher’s Household for Rural Households Economic and Food Security in in East Java's Coasts.This research aims to analyze impact of economics changes parameter, such as increasing of fuel price, primary consumption and households strategies to increase their incomes by adding non-fishing work outflow. It uses a simulation model approach with Two Stage Least Squares (2SLS) method to analyze economics changes and food security of fishers households in Pasuruan and Trenggalek districts, East Java Province. Simulation results show that 30% increase in fishers operational cost and primary consumption price should be fulfilled by 15% increasing of work outflow from husband and wife in household. This increasing also leads to declining of fisherman households' food security. This research conclude that smallscale fishers household can keep their households food security by utilizing of theirs wife leisure timeproductivelyoriented to market.

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