No abstract

In order to verify the carbon source and trophic position of the main species of fishes, of the Paraná River floodplain, we analysed the proportion of stable carbon (delta 13C) and nitrogen (delta 15N) isotopes in muscle of fishes sampled in the rainy season. We analyzed adult individuals of Loricariichthys platymetopon, Schizodon borellii, Leporinus lacustris, Auchenipterus osteomystax, Iheringichthys labrosus, Leporinus friderici, and Serrasalmus marginatus. These data were compared with the results obtained by the analyzing stomach contents. The primary producers found in the Baía River were the C3 plants (riparian vegetation, macrophytes, periphyton, and phytoplankton) and the C4 plants (macrophytes). The results of the contribution analysis revealed that the carbon used by the species was derived from C3 plants. According to the trophic position estimates (diet and delta 15N), the species primarily consumed Loricariichthys platymetopon, Schizodon borellii, Leporinus lacustris, and Leporinus friderici and, secondarily Auchenipterus osteomystax, Iheringichthys labrosus, and Serrasalmus marginatus. There was no significant difference between the two methods utilized.

We thank two anonymous reviewers and Shang-Ping Xie for very helpful comments on earlier versions of the manuscript.

Abstract-The domain name system (DNS) is a complex distributed database on which most Internet services rely on. As its monitoring is critical, it is necessary to continuously monitor DNS traffic for identifying anomalies, measuring performance, and generating usage statistics. This paper describes the design and implementation of a distributed realtime DNS monitoring system, that is able to monitor the authoritative name servers of the .it country code Top Level Domain (ccTLD). In addition to the production of usage records, it is able to understand trends, characterize economical relationships, and also track suspicious activities.

Abstract-The DNS is one of the core protocols on which the Internet is built upon. Hidden behind higher-level protocols such as email and web, it carries valuable information that can be exploited for understanding trends and preferences of the Internet community.In this paper we propose novel methodologies for modelling DNS traffic that allow Internet domains, DNS resolvers and their interactions to be represented effectively by means of graphs. DNS traffic collected at ".it" ccTLD DNS domain servers has been used to validate this work on a large scale. We found highly-skewed, fat-tailed domain and resolver degree frequencies, obeying power laws at least in their tails. These findings shed light on the the scale-free nature of the DNS ecosystem, where a few domains and a few resolvers are responsible for most of the DNS activity.