Detecting Population Regulation of Winter Flounder from Noisy Data

Year-class size of marine fish is thought to be determined during the first year of life, with density-dependent mortality during the larval or juvenile stages. However, investigations of such dynamics are often limited by data availability. To test this paradigm for winter flounder (Pseudopleuronectes americanus) in Narragansett Bay, Rhode Island, the abundances of 29 year classes moving through seven life stages were analyzed with a novel extension of key-factor analysis. Evidence of density dependence was identified between the egg and July young-of-the-year stages and high process-error variance was detected throughout the life cycle, suggesting year-class size is not fully determined until age-2. However, the first summer appeared to be a critical life stage for winter flounder, during which high temperatures, hypoxia, and predator abundance contributed to increased mortality rates behind a long-term population decline. Due to its general data requirements, the key-factor analysis method developed here may be applied to other marine populations to identify the impacts of external stressors at particular life stages and the degree to which they are compensated by density-dependent processes.

The Construction, Description, and Analysis of Age-Specific Life-Tables

Methods for constructing a life-table and budget for a species are described, and the various methods for the analysis of stage-frequency data reviewed. Stage-frequency data comprise counts of the individuals in different development stages in samples taken from a population over a period of time. The analysis of stage-frequency data to estimate the durations of the stages, the numbers entering stages, and survival rates is described. Examples of survivorship curves are presented, and the calculation of population growth rate described. Analysis of life-table data and demographic methods, including key-factor analysis, are described.

Supply Chain Performance Influencer in Construction Domain: A Key Factor Analysis

In this study the improvement of supply chain process based on the supply chain management has been considered. In this regard, two vital factor of time and cost has been taken into account to optimize the process of product delivery. To harness the available methods, among the all options, the construction company’s integration has been elicited in order to improve the business process by concentrating best logistic and supply chain factors to improve the construction quality and standards. By ensuing the proposed methods, the importance of supply chain relationships in construction companies as well as efficiency of the flowed information in terms of relevant data to improve customer and supplier relation has been manifested. In the strategies, followed aforementioned trends, the best potential tools for improvement of constructed companies have been identified. At the end, implementing the mentioned strategies, the obtained results attested the quality performance and supply chain management expediency.