The main objective of this research is to assess the existence （or lack） of media concentration in the Portuguese dailies newspaper sector, and to evaluate the extension to which this situation may be compromising f...The main objective of this research is to assess the existence （or lack） of media concentration in the Portuguese dailies newspaper sector, and to evaluate the extension to which this situation may be compromising fundamental society values： freedom of speech and right of access to information. Authors resorted to market indicators, namely total average circulation,number of copies per issue, business volume and advertising investments. These indicators are found to be complementary： some indicators evaluate group position in the readers＇ market, whereas other evaluates group position in the general market and the advertising market in particular. Based in this market information, we used quantitative models （HII, CR4 and Noan） to measure de concentration in the newspaper segment. Additionally we tried to demonstrate that to analyze the dailies newspaper concentration situation in Portugal a holist perspective of the media market is needed, using a country context to understand some local characteristics and market structure and political, economic, social and technological dynamics. Additionally, there are evidences that existing concentration indexes are not conclusive because of potential replacement effects in the Portuguese media sector.展开更多
Despite fluctuations in embryo size within a species,the spatial gene expression pattern and hence the embryonic structure can nonetheless maintain the correct proportion to the embryo size.This is known as the scalin...Despite fluctuations in embryo size within a species,the spatial gene expression pattern and hence the embryonic structure can nonetheless maintain the correct proportion to the embryo size.This is known as the scaling phenomenon.For morphogen-induced patterning of gene expression,the positional information encoded in the local morphogen concentrations is decoded by the downstream genetic network(the decoder).In this paper,we show that the requirement of scaling sets severe constraints on the geometric structure of such a local decoder,which in turn enables deduction of mutants’behavior and extraction of regulation information without going into any molecular details.We demonstrate that the Drosophila gap gene system achieves scaling in the way consistent with our theory—the decoder geometry required by scaling correctly accounts for the observed gap gene expression pattern in nearly all maternal morphogen mutants.Furthermore,the regulation logic and the coding/decoding strategy of the gap gene system can also be revealed from the decoder geometry.Our work provides a general theoretical framework for a large class of problems where scaling output is achieved by non-scaling inputs and a local decoder,as well as a unified understanding of scaling,mutants’behavior,and gene regulation for the Drosophila gap gene system.展开更多
文摘The main objective of this research is to assess the existence （or lack） of media concentration in the Portuguese dailies newspaper sector, and to evaluate the extension to which this situation may be compromising fundamental society values： freedom of speech and right of access to information. Authors resorted to market indicators, namely total average circulation,number of copies per issue, business volume and advertising investments. These indicators are found to be complementary： some indicators evaluate group position in the readers＇ market, whereas other evaluates group position in the general market and the advertising market in particular. Based in this market information, we used quantitative models （HII, CR4 and Noan） to measure de concentration in the newspaper segment. Additionally we tried to demonstrate that to analyze the dailies newspaper concentration situation in Portugal a holist perspective of the media market is needed, using a country context to understand some local characteristics and market structure and political, economic, social and technological dynamics. Additionally, there are evidences that existing concentration indexes are not conclusive because of potential replacement effects in the Portuguese media sector.
基金supported by the National Natural Science Foundation of China(12090053 and 32088101)。
文摘Despite fluctuations in embryo size within a species,the spatial gene expression pattern and hence the embryonic structure can nonetheless maintain the correct proportion to the embryo size.This is known as the scaling phenomenon.For morphogen-induced patterning of gene expression,the positional information encoded in the local morphogen concentrations is decoded by the downstream genetic network(the decoder).In this paper,we show that the requirement of scaling sets severe constraints on the geometric structure of such a local decoder,which in turn enables deduction of mutants’behavior and extraction of regulation information without going into any molecular details.We demonstrate that the Drosophila gap gene system achieves scaling in the way consistent with our theory—the decoder geometry required by scaling correctly accounts for the observed gap gene expression pattern in nearly all maternal morphogen mutants.Furthermore,the regulation logic and the coding/decoding strategy of the gap gene system can also be revealed from the decoder geometry.Our work provides a general theoretical framework for a large class of problems where scaling output is achieved by non-scaling inputs and a local decoder,as well as a unified understanding of scaling,mutants’behavior,and gene regulation for the Drosophila gap gene system.
