Simultaneous quantification of depolymerization and mineralization rates by a novel 15N tracing model

The depolymerization of soil organic matter, such as proteins and (oligo-)peptides, into monomers (e.g. amino acids) is currently considered to be the rate-limiting step for nitrogen (N) availability in terrestrial ecosystems. The mineralization of free amino acids (FAAs), liberated by the depolymerization of peptides, is an important fraction of the total mineralization of organic N. Hence, the accurate assessment of peptide depolymerization and FAA mineralization rates is important in order to gain a better process-based understanding of the soil N cycle. In this paper, we present an extended numerical 15N tracing model Ntrace, which incorporates the FAA pool and related N processes in order to provide a more robust and simultaneous quantification of depolymerization and gross mineralization rates of FAAs and soil organic N. We discuss analytical and numerical approaches for two forest soils, suggest improvements of the experimental work for future studies, and conclude that (i) when about half of all depolymerized peptide N is directly mineralized, FAA mineralization can be as important a rate-limiting step for total gross N mineralization as peptide depolymerization rate; (ii) gross FAA mineralization and FAA immobilization rates can be used to develop FAA use efficiency (NUEFAA), which can reveal microbial N or carbon (C) limitation

Long-term and realistic global change manipulations had low impact on diversity of soil biota in temperate heathland

In a dry heathland ecosystem we manipulated temperature (warming), precipitation (drought) and atmospheric concentration of CO(2) in a full-factorial experiment in order to investigate changes in below-ground biodiversity as a result of future climate change. We investigated the responses in community diversity of nematodes, enchytraeids, collembolans and oribatid mites at two and eight years of manipulations. We used a structural equation modelling (SEM) approach analyzing the three manipulations, soil moisture and temperature, and seven soil biological and chemical variables. The analysis revealed a persistent and positive effect of elevated CO(2) on litter C:N ratio. After two years of treatment, the fungi to bacteria ratio was increased by warming, and the diversities within oribatid mites, collembolans and nematode groups were all affected by elevated CO(2) mediated through increased litter C:N ratio. After eight years of treatment, however, the CO(2)-increased litter C:N ratio did not influence the diversity in any of the four fauna groups. The number of significant correlations between treatments, food source quality, and soil biota diversities was reduced from six to three after two and eight years, respectively. These results suggest a remarkable resilience within the soil biota against global climate change treatments in the long term

The Nitrogen Cycle in Soil – Climate Impact and Methodological Challenges in Natural Ecosystems

Nitrogen (N) is a fundamental element for life, and limiting in many terrestrial ecosystems. In non-N-fertilized ecosystems, the N inputs can be low, and the nutrient availability for plants is determined by the internal cycling of N. The N availability might alter with different factors, such as climate change, forest management practices, and tree species. Soil N cycling is investigated using stable isotopes, where the activity in the soil can be monitored over time. The overall aim of this thesis is to increase the understanding of the N cycle in natural and semi-natural ecosystems and the environmental factors important for nutrient cycling. The results show that all sites investigated in this thesis had higher NH4+ turnover than NO3- turnover. The mineralization rates were highest in the site with the lowest C:N ratio, and the lowest mineralization rates and the highest C:N ratio in the spruce forests, which demonstrate the importance of organic matter quality on gross N transformation rates. The N cycle responses to combined climate treatments were generally lower than responses to single climate treatments. For some processes, we observed opposing responses for eCO2 as single and main treatment compared to the plots receiving the full treatment. This point to the importance of conducting multifactor climate change experiments, as many feedback controls are yet unknown. Gross nitrification was lowered with fertilization in a northern boreal forest, which is an interesting result in the light of the very low nitrous oxide (N2O) emissions from the investigated site, despite heavy annual fertilization of 50–70 kg ha-1. Moreover, the results from an experiment with soil of common origin and land history showed generally higher gross mineralization, immobilization and nitrification rates a beech stand compared to a spruce stand. The beech stand had also higher initial concentration of nitrate (NO3-) which indicates a more NO3- based N cycling. Finally, numerical modeling together with 15N tracing is an improvement for simultaneously determining free amino acid (FAA) mineralization, peptide depolymerization and gross N mineralization rates, compared to analytical solutions. This thesis confirms that N cycling in natural ecosystems is governed by the properties of the soil, vegetation and climate, but also that the experimental set-up strongly affects the outcome of the experiment. In turn, this affects the potential of doing reliable experiments, especially in ecosystems where the external inputs of N are very low. The thesis also highlights some methodological challenges that lie in the future of N cycling research

Regional Integration in Africa : Is the African Union facing legitimacy problems?

The African Union (AU) is the continent-wide project for economic and political integration in Africa. It takes inspiration from the European Union (EU), where two major problems could be discerned. Firstly, the European and the African context differ from each other, economically,socially and politically. Secondly, the EU itself has been criticized for legitimacy problems,including ineffective decision-making processes, not satisfying tasks for the European Parliament (EP), and low voter turnout in the elections to the EP. Thus, it is interesting to ask whether it ispossible to create a legitimate African Union with the objectives to unite and strengthen the African continent through political and economic actions, when it takes inspiration from a quasisupranational organization which operates in a different political setting, and whose legitimacy hasbeen highly questioned. The purpose of this paper was to examine and discuss whether the AU faces legitimacy problems,and if it does, what kind of legitimacy-problems? To specify the purpose, three questions were posed: What is the status of the process of making the Pan-African Parliament (PAP) a legislativeand popularly authorized organ? What are the AU's ambitions and means for building a common African identity? How is the AU financed, and what can be said about the economy's effect on the AU'scapacity to perform effectively? The conclusions show that the AU seems to be facing legitimacy problems. Firstly, a legislative organ is important in this kind of organization, and in order to be a legitimate legislative organ it is important to have the representatives elected by the people. The project of transforming the PAPinto a legislative organ has started, but to let the people elect their representatives to the PAP has notyet been provided for. Secondly, it seems like the AU have problems concerning funding. The basic means for funding the AU is through member-state contributions, and the AU suffers from outstanding payments, delayed payments, and some also argues that the member-state contributions are too small. This is a major obstacle for the union's development, since a weak economy willhinder the AU institutions' performance. The AU also stands before a huge task of creating a sharedAfrican identity – that is, creating the African demos. The ambitions for carrying out this project are expressed in different AU-documents, and the PAP have a great role in this project. Although, tostudy how this project is going was not a part of this paper's purpose and is left for further research

Kannibalism av varumärken inom multibrandföretag

Problem: Vårt problemområde rör sig kring att studera fenomenet kannibalism i syfte till att beskriva de skepnader fenomenet tar i vår fallstudie. Vidare diskuteras konsekvenser av kannibalism samt metoder för att eventuellt undvika kannibalism. Följande frågeställningar är ställda: 1. Hur uppstår fenomenet kannibalism i ett multibrandföretag? 2. Vilka är konsekvenserna av kannibalism? 3. Vad kan man göra för att undvika kannibalism? Syfte: Syftet med denna uppsats är att kartlägga fenomenet kannibalism för att förstå dess olika skepnader som kan framkallas av en multibrandingstrategi. Genom att studera när och hur kannibalism uppstår i ett multibrandföretag vill vi skapa en förståelse för konsekvenserna av kannibalism och redogöra för sätt att undvika kannibalism i de fall det är önskvärt. Metod: Vi har använt oss av en kvalitativ metod med utgångspunkt i en fallstudie när vi genomfört våra intervjuer. Det emiriska materialet är hämtat från ett multibrandföretag där vi utfört intervjuer med en varumärkesexpert samt 16 styck intervjuer med konsumenter. Slutsatser: Kannibalism är mer eller mindre situationsspecifikt. Unilever produktkategori bordsmargarin löper risk för kannibalism till följd av variationssökande beteende, gemensamma attribut, snarlik segmentering och lågt engagemang. Önskar företaget undvika överdriven kannibalism finns det sätt att gör detta på. Varumärkeslojalitet, känslomässigt beteende, vana, tvåproduktstrategin, varumärkesidentitet och unika attribut är exempel på tillstånd som kan lindra den oönskade formen av kannibalism

Hur uppfattas image i olika kulturer?

Sammanfattning Titel: Hur uppfattas image i olika kulturer? Problemformulering: Det första steget i vår problemundersökning är att studera vilken image BabyBjörn vill föra ut på de olika nationella marknaderna och vilka tankar som ligger bakom den eller de images man för ut. Därefter ställs följande frågeställning: Hur inverkar kultur på image och uppfattas imagen olika i den svenska respektive franska kulturen? Syfte: Syftet med denna uppsats är att studera hur ett företags image kan te sig på en internationell marknad samt att se hur köpbeteendet skiljer sig två länder emellan. Undersökningen strävar efter att förstå hur internationellt imageskapande kan utvecklas och hur image uppfattas av konsumenter från olika kulturer och om de olika kulturerna, till vilket företaget vänder sig, påverkar uppfattningen av företagets image. Metod: Vi har valt att använda oss av kvalitativa djupintervjuer. För att få in de primärdata som vi behövde genomförde vi tre expertintervjuer och fyra konsumentintervjuer i Frankrike. På samma vis har vi genomfört tre expertintervjuer och fyra konsumentintervjuer i Sverige. Slutkommentar: I denna undersökning tycker vi oss inte kunna urskilja markanta skillnader i kultur och inte heller i köpbeteende mellan de franska och de svenska respondenterna. Vi ser skillnader i kunskap om BabyBjörn och i anskaffning av information. Det har varit svårt att se hur kultur påverkar image men vi har försökt se hur skillnader i beteende, kunskap och motivation påverkar image. Vi ser att imageskapandet kan utvecklas, att kultur påverkar vårt köpbeteende, samt att köpbeteendet i viss mån skiljer sig åt mellan de franska och de svenska respondenterna