the main objective of the present study was qualitative assessment of golden gray mullet stocks by using indicators of overfishing in iranian waters of the caspian sea during a long period (1991-2011). three fisheries indicators in catch were: 1. percentage of mature fish, with 100% as target; 2. percent of specimens with optimum length, with 100% as target; and 3. percentage of mega-spawners, ...

Purpose – Open-access mega-journals (OAMJs) represent an increasingly important part of the scholarly communication landscape. OAMJs, such as PLOS ONE, are large scale, broad scope journals that operate an open access business model (normally based on article-processing charges), and which employ a novel form of peer review, focussing on scientific “soundness” and eschewing judgement of novelty...

Central Business Districts (CBDs) are an apparent structural type of large cities. Although the conceptual definition of CBDs is mostly functional, this urban structure type has characteristic physical features. The paper presents a conceptual framework to map these CBDs using physical parameters. We identify physical parameters from the published literature and statistically designate the CBD ...

With the trend toward greater urbanization and the rapid emergence of mega-cities continuing unabated, many policy makers ask themselves whether some cities are becoming too large, and whether policies should be aimed at stimulating the growth of intermediate-sized cities. In this chapter we use a simple model of a system of cities, together with some basic urban and aggregate data, to answer s...