An injection technique, in which undisturbed soil cores are labelled with ³²P to study dissolution of phosphate fertilisers in the soil, was evaluated in field and glasshouse trials. When ³²P was injected between 0-150 mm depths of the undisturbed soil columns and fertilisers applied at the surface, the amounts of fertiliser P dissolved, as measured by the increases in the exchangeable P pools, were overestimated. Three possible reasons were suggested: (i) the interaction between surface-applied fertiliser, ³²P injected through the whole soil column, and the vertical decline in root density, (ii) the decline of specific activity in the exchangeable P pool due to losses of ³²P to nonexchangeable P pools and continuous addition of P from fertiliser dissolution, and (iii) non-uniform distribution of ³²P vis-a-vis ³¹P phosphate. The injection technique may be employed to assess the effectiveness of phosphate fertilisers by introducing a concept, the fertiliser equivalent (FE). The FE is a measure of the amounts of soil exchangeable P that the fertilisers are equivalent to in supplying P to plants, when applied at the specific location. Soluble single superphosphate (SSP) applied at the surface of undisturbed grassland soil cores (Tekapo fine sandy loam), was much more effective than surface-applied unground North Carolina phosphate rock (NCPR) and 30% acidulated NCPR with phosphoric acid (NCPAPR) within the 56 day period of plant growth. An isotopic dilution method, based on tracer kinetic theory, was developed to study the rates of dissolution (F in) and retention (F out) of phosphate fertilisers in the soil in growth chamber experiments. The estimation of F in and F out required labelling of the soils with carrier-free ³²P and determination of the corresponding values of the specific activities of the exchangeable P pools, SA₁ and SA₂, and the sizes of the exchangeable P pools, Q₁ and Q₂, at times t₁ and t₂. Most of the phosphate in the monocalcium phosphate (MCP) solution entered the exchangeable P pool immediately after addition to the soils (Tekapo fine sandy loam and Craigieburn silt loam), and there was little further phosphate input. With increasing periods of incubation, the phosphate was quickly transformed to less rapidly exchangeable forms. In the soils treated with ground North Carolina phosphate rock (<150 µm, NCPR) or partially acidulated (30%) NCPR with phosphoric acid (NCPAPR), the initial exchangeable P pools were not as large as those in the soils treated with MCP, but were maintained at relatively stable concentrations for extended periods, due to the continuous dissolution of PR materials and to lower rates of pretention. An increase in P-retention caused a slight rise in the rate of PR dissolution, but also a rise in the rate of P-retention by the soil. The rate of dissolution was higher at a lower application rate in relative terms, but smaller in absolute terms. The trends in the changes of plant-available P in the soils, measured by the water extractable P, Bray I P and Olsen P, correspond to those predicted by the F in and F out values. The average rates of dissolution between 1-50 and 50-111 days estimated by the F in, however, were higher than those estimated by extractions with 0.5 M NaOH followed by 1 M HCl, and with 0.5 M BaCl₂/TEA. This is partly because the Fin values reflect a plant growth effect on PR dissolution. The relative agronomic effectiveness of NCPR and NCPAPR with respect to MCP was higher after 50 and 111 days of incubation than after 1 day. The F in values were included in all the two-variable models constructed by stepwise regression to describe the relationship between plant P uptake and soil measurements. The amounts of variation in plant P uptake accounted for by the regression model was significantly improved by including F in in the model. This indicates the importance of fertiliser dissolution rates in affecting soil P supply, when phosphate fertilisers differing in solubility are applied.

Abstract Sharing is emerging as one of the megatrends influencing future business opportunities, and wireless communications is no exception to this development. Future mobile broadband networks will operate on different types of spectrum bands including shared spectrum, which calls for changes in the operation and management of the networks. The creation and capture of value by the different players in the mobile broadband ecosystem is expected to change due to regulation, technology, and business landscape related drivers that concern not only spectrum sharing, but also sharing of other resources such as infrastructure, technologies, or data. This thesis examines the key business and technology enablers needed to exploit spectrum sharing in mobile broadband networks, and presents the business model characteristics and strategic choices that spectrum sharing concepts support. Action research and integral scenarios methodologies were applied for strategic and business analysis utilizing the capacity and expertise of the policy, business and technology research communities. The thesis introduces a new approach to analyze the scalability of the spectrum sharing concepts and their business model elements utilizing sharing economy antecedent factors. The results indicate that all analyzed sharing concepts meet basic requirements to scale. The Licensed Shared Access (LSA) leverages existing assets and capabilities of the mobile network operator domain, the Citizens Broadband Radio Service (CBRS) extends the business model dynamics from connectivity to content, context and commerce, and the hybrid usage of Ultra High Frequency (UHF) band by Digital Terrestrial TV (DTT) and downlink Long Term Evolution (LTE) (HUHF) enables new collaborative opportunities between converging communication, Internet and media domains. The thesis validates the feasibility of spectrum sharing between mobile broadband networks and other types of incumbent spectrum users utilizing Finnish cognitive radio field trial environment (CORE), and expands the notion of spectrum sharing beyond the mobile broadband domain to be applied to other wireless systems including the media and broadcasting. The presented results can be used in developing the future mobile broadband systems enhanced with innovative spectrum sharing enabled business models to cope with the growing demand for capacity and new services by humans and machines. / Tiivistelmä Jakamistalous on yksi suurista tulevaisuuden liiketoimintamahdollisuuksiin vaikuttavista trendeistä, eikä langaton tietoliikenne ole tässä poikkeus. Tulevaisuuden laajakaistaiset matkapuhelinverkot tulevat hyödyntämään erityyppisiä radiotaajuuksia, kuten jaettuja taajuuskaistoja, mikä vaatii muutoksia verkkojen toimintoihin ja hallintaan. Eri toimijoiden arvonluonti- ja ansaintamahdollisuuksien odotetaan muuttuvan näissä liikkuvan laajakaistan ekosysteemeissä regulaation, teknologian ja liiketoimintaympäristön kehittyessä, ei vain taajuuksien jakamisessa, vaan myös kun kyseessä on muiden resurssien kuten infrastruktuurin, teknologioiden tai tiedon jakaminen. Väitöskirja tutkii teknologia- ja liiketoimintaedellytyksiä taajuusjakomenetelmille matkapuhelinverkoissa, sekä esittelee ja analysoi menetelmien mahdollistamia liiketoimintamalleja ja strategisia valintoja. Strategia- ja liiketoiminta-analyyseissä käytettiin toimintatutkimus- ja skenaariomenetelmiä poikkitieteellisissä tutkimusprojekteissa yhteistyössä reguloinnin, liiketoiminnan ja tekniikan tutkimusyhteisöjen kanssa. Tutkimus esittelee uuden lähestymistavan taajuusjakotekniikoiden liiketoimintamallien skaalautuvuuden analysointiin jakamistalouden määritelmiä hyödyntäen. Tulokset osoittavat, että kaikki tutkitut tekniikat täyttävät perusedellytykset skaalautuvuudelle; Licensed Shared Access (LSA) hyödyntäen matkapuhelinoperaattorin olemassa olevia resursseja ja kyvykkyyksiä, Citizens Broadband Radio Service (CBRS) laajentaen liiketoimintamalleja tietoliikenteestä sisältöön, kontekstiin ja kaupankäyntialustoihin, sekä digitaalitelevision ja langattoman LTE-tekniikan hybridikäyttö UHF-taajuuskaistalla (HUHF) mahdollistaen uusia liiketoimintamahdollisuuksia lähentyvien tietoliikenne-, Internet- ja mediaekosysteemien välillä. Väitöskirja tulokset vahvistivat taajuuden jakamisen soveltuvuuden liikkuvan laajakaistaverkon ja saman taajuusalueen eri teollisuudenalan haltijan välillä suomalaisessa CORE kenttätestausympäristössä, ja laajensivat taajuusjakotekniikan sovellettavuutta myös muihin langattomiin järjestelmiin sisältö- ja mediajakelussa. Esitettyjä tuloksia voidaan hyödyntää tulevaisuuden langattomien laajakaistaverkkojen kehitystyössä vastaamaan ihmisten ja koneiden kasvaviin tietoliikennepalveluiden ja -kapasiteetin tarpeisiin hyödyntäen tehokkaita taajuusjakotekniikoita ja niiden mahdollistamia innovatiivisia liiketoimintamalleja.

In Mitteleuropa werden zukünftig häufigere Trocken- und Hitzeperioden mit wirtschaftlichen Einbußen in der Waldwirtschaft erwartet. Die Douglasie (Pseudotsuga menziesii (Mirb.) Franco) wird als Alternative für die wirtschaftlich bedeutsame, jedoch trockenheitsempfindliche Fichte diskutiert (Picea abies (L.) H.Karst.). Zwei Unterarten, die Küsten- (FDC) und die Inlandsdouglasie (FDI), sind im ausgedehnten natürlichen Verbreitungsgebiet in Nordamerika beheimatet, welches ein großes Potenzial für die Auswahl produktiver und trockenresistenter Herkünfte bietet. Unser Ziel war, die Trockenreaktion verschiedener Douglasienherkünfte unter Verknüpfung morphologischer und physiologischer Parameter und die der Trockenheitsresistenz bzw. -empfindlichkeit zugrundeliegenden Mechanismen zu erforschen. Ein Herkunftsversuch in Südwestdeutschland ermöglichte die Untersuchung 50-jähriger Douglasien verschiedener Herkünfte entlang eines Höhengradienten. Unter kontrollierten Bedingungen simulierten wir die Effekte einer Hitzewelle auf Jungbäume zweier Provenienzen. Wir analysierten die Kohlenstoff- und Sauerstoff-Stabilisotopenzusammensetzung, den Gaswechsel der Blätter, Veränderungen im Stoffwechsel und das Baumwachstum. Unsere Ergebnisse zeigen bei FDC aus humiden Regionen hohe Wachstumseinbußen unter Trockenheit und moderat bis stark verringerte stomatäre Leitfähigkeit, unterstützt durch Photoprotektion. FDC aus Regionen mit starker Sommertrockenheit reagierten kaum mit Stomataschluss und Wachstumseinbußen auf Trockenheit, jedoch mit starker Osmoregulation und Monoterpen-Emissionen, welche zur Trockenresistenz beitragen könnten. FDI aus einer ariden Region zeigten hohe An, geringes Wachstum und stark antioxidative und photoprotektive Mechanismen. Die Herkünfte unterscheiden sich stark in ihrer Trockenreaktion und ihren Schutzmechanismen. Der Anbau trockenresistenter Herkünfte wird an Standorten von Vorteil sein, für die eine Häufung von ariden Sommerperioden vorhergesagt wird. / In Central Europe, more frequent periods of dry and hot weather are expected in the future with economic losses in the forestry sector. Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) is discussed as a timber species alternative to the economically important but drought-sensitive spruce (Picea abies (L.) H. Karst.). Two subspecies, the coastal (FDC) and the interior Douglas-fir (FDI), are native to an extensive natural range in North America, offering a great potential for the selection of productive and drought tolerant provenances. Our goal was to investigate the drought response of different Douglas-fir provenances on the morphological and physiological level, as well as the mechanisms underlying drought resistance or susceptibility. A provenance trial in southwestern Germany established in 1958 allowed the study of 50-year-old Douglas-fir trees of diverse provenances along a height gradient. Under controlled conditions, we simulated the effects of a heat wave on young trees of two provenances. We analyzed carbon and oxygen stable isotopic composition, leaf gas exchange, changes in metabolism and tree growth. FDC from humid regions responded to drought with strong growth decline and a medium to strong stomatal closure, supported by enhanced instantaneous photoprotection. FDC from regions with very dry summer conditions showed a small growth decline and anisohydric regulation of stomatal conductance under drought, supported by high levels of osmotic adjustment. High monoterpene emissions might contribute to the drought resistance. FDI from an arid region showed high assimilation rates, low growth potential and a high antioxidant, photoprotective, drought and heat protective potential. The provenances differ greatly in their dry reaction and their protective mechanisms. The cultivation of drought resistant crops will be beneficial at sites predicted to accumulate arid summer periods.