Predation is a strong dective force on invertebrate prey. Asellus aquaticus differs in pigmentation reed and submerged vegetation habitats in lakes. Light pigmented individuals al vegetation dominated by Chara sp. while dark pigmented individuals dominate in the Reeds. These differences have been hypothesized to result from background matching.

In this thesis I discuss and analyze different factors, and different circumstances, that influence identity negotiation among the north american indians. I do this mainly by using two models.The first one is Druckmans three dimensions of identity; negotiating identity, durability of identity and spread of identity. Depending on how the identity fits in these dimensions one can se if, or how, they influence the negotiability.My second model for analyzing is Reeds ?fasteing and unfastening identity?, using this model I have tried to understand during what circumstances the identity is negotiable. The identity is more or less negotiable depending on where the indians live, who they are living with and also on their inheritance.My results shows that the indian identity is changing and developing over time but the main characteristics still remains the same.

This study was made as a part of a feasibility study on a polishing wetland at Rimbo wastewater plant (wwp) in Norrtälje municipality. The wwp had to decrease the nitrogen discharge to reach the limit 15 mg tot-N/l. The nitrogen in the outlet was mainly in the form of nitrate, hence the wetland mainly ought to support denitrification. The proposed area for the wetland was situated right next to the wwp and was already in the municipalitys posession. One aim of this study was to examine what spieces of plants needed to achieve highest possible denitrification.

En säker informationskanal med hög överföringskvalitet krävs i dessa dagar när informationsöverföringen ökar för varje år som går. Det finns olika sätt att skapa detta. Antingen genom att se till att överföringsmediet är av mycket hög kvalitet eller att skapa en skyddsmekanism som gör att de överföringsfel som kan uppstå kan detekteras och även korrigeras om man önskar detta. Denna uppsats handlar om detta, att kunna detektera och korrigera fel. Denna gren inom matematiken kallas kodningsteori.Uppsatsen presenterar grunden för kodningsteorin, för att sedan presentera några vanligt förekommande kodningsalgoritmer, Hamming koder, BCH koder, Reed-Solomon.