Natural Science in the Bothnian Sea During 1975-2008: A Review

The Baltic Sea is one of the most studied areas in the world. However, parts of its northernmost reach, the Bothnian Sea, seem to be under represented in the natural scientific literature compared to other parts of the Baltic. The Bothnian Sea represents a unique inland sea environment for the scientific community to study due to its shallowness and low salinity. The natural sciences research carried out on the Bothnian Sea has been reviewed between 1975 and 2008. This time period was chosen to continue on from an earlier review paper ending in 1974. Along with the number of papers published the goal was also to review the content of the papers, indentifying dominating themes to evaluate gaps in the current knowledge on the Bothnian Sea and provide recommendations for topics of future research focus. In a classification into specific research topics biodiversity was the leading research focus followed by chemical and physical oceanography, pollution and toxins, and fish biology and fisheries. The current good condition of the Bothnian Sea is highly valued with its historically less eutrophic and clearer waters when compared to the Baltic. However, today the Bothnian Sea is facing eutrophication resulting from nutrient-rich water transported by the many rivers draining into it from Sweden and Finland making it an area in need of protection and preservation. More human activity will also concentrate on the Bothnian Sea in the future. Therefore the use of the sea and its coastal areas must be planned carefully to minimize the harmful effects of this increasing human activity. To achieve this more information is needed for the basis of Integrated Coastal Zone Management (ICZM) and maritime spatial planning (MSP). For example, for the Bothnian Sea the information on the underwater nature which is essential for ICZM is so far missing to a large extent. Specific biological, chemical and physical oceanographic information is needed to combine with economic analyses and environmental policies regarding this region. More research of a multidisciplinary nature is required on the unique Bothnian Sea environment and this we feel is best achieved through a joint Finnish-Swedish research strategy.

Response of fine root respiration to variations in biotic and abiotic factors in a mixed Mediterranean forest affected by drought-induced secondary succession

Understanding the factors controlling fine root respiration (FRR) at different temporal scales will help to improve our knowledge about the spatial and temporal variability of soil respiration (SR) and to improve future predictions of CO2 effluxes to the atmosphere. Here we present a comparative study of how FRR respond to variability in soil temperature and moisture in two widely spread species, Scots pines (Pinus sylvestris L.) and Holm-oaks (HO; Quercus ilex L.). Those two species show contrasting water use strategies during the extreme summer-drought conditions that characterize the Mediterranean climate. The study was carried out on a mixed Mediterranean forest where Scots pines affected by drought induced die-back are slowly being replaced by the more drought resistant HO. FRR was measured in spring and early fall 2013 in excised roots freshly removed from the soil and collected under HO and under Scots pines at three different health stages: dead (D), defoliated (DP) and non-defoliated (NDP). Variations in soil temperature, soil water content and daily mean assimilation per tree were also recorded to evaluate FRR sensibility to abiotic and biotic environmental variations. Our results show that values of FRR were substantially lower under HO (1.26 ± 0.16 microgram CO2 /groot·min) than under living pines (1.89 ± 0.19 microgram CO2 /groot·min) which disagrees with the similar rates of soil respiration previously observed under both canopies and suggest that FRR contribution to total SR varies under different tree species. The similarity of FRR rates under HO and DP furthermore confirms other previous studies suggesting a recent Holm-oak root colonization of the gaps under dead trees. A linear mixed effect model approach indicated that seasonal variations in FRR were best explained by soil temperature (p<0.05) while soil moisture was not exerting any direct control over FRR, despite the low soil moisture values during the summer sampling. Plant assimilation rates were positively related to FRR explaining part of the observed variability (p<0.01). However the positive relations of FRR with plant assimilation occurred mainly during spring, when both soil moisture and plant assimilation rates were higher. Our results finally suggest that plants might be able to maintain relatively high rates of FRR during the sub-optimal abiotic and biotic summer conditions probably thanks to their capacity to re-mobilize carbon reserves and their capacity to passively move water from moister layers to upper layers with lower water potentials (where the FR were collected) by hydraulic lift.

Tutustumiskierros terrorismintutkimukseen

Kirjallisuusarvostelu

DFT study on low molecular weight α,α-ditert-butyl-4H-cyclopenta[2,1-b,3;4-b']dithiophene and α,α-ditert-butyl-4H-cyclopenta[2,1-b,3;4-b']dithiophene S-oxide bridged derivatives

The equilibrium geometries of α,α-ditert-butyl-4H-cyclopenta[2,1-b,3;4-b']dithiophene (DBDT) and α,α-ditert-butyl-4H-cyclopenta[2,1-b,3;4-b']dithiophene S-oxide (DBDTO) were studied at the DFT level of theory with a standard 6-311G* basis set. The molecular structures of the DBDT series were more planar than the corresponding DBDTO series, as revealed by dihedral angles. The UV-visible absorption calculated at TD-DFT/6-311G* showed two absorption peaks for all the molecules except C=S and C=O bridged molecules. In DBDTOs, C=S and C=O bridged molecules showed three and four absorption peaks, respectively. The DBDTOs had lower band gaps and longer wavelengths compared to the corresponding DBDTs.

Química entre a microcamada superficial oceânica e os aerossóis marinhos

The sea surface microlayer (SML), although poorly understood, is important in biogeochemical cycling and sea - air exchanges; it is a source or a sink for a range of pollutants. In this paper, an overview of sampling techniques and the role of SML in biogeochemical cycles and climate is presented. The chemical and biological nature of the ocean surface film and its interaction with atmospheric aerosols are discussed. Special attention is given to organic constituents, gel-like compounds, surfactants, halogenated compounds, and metals. Estimates of air - sea exchange fluxes-with focus on organic carbon, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls-are compiled. In addition, research gaps in the chemical composition of marine aerosols and their relationship with SML are described.

UTILIZAÇÃO DO COMPÓSITO NANOESTRUTURADO SIO2/TIO2NA FOTODEGRADAÇÃO DE CORANTES TÊXTEIS COM LUZ SOLAR NATURAL

SiO2/TiO2 nanostructured composites with three different ratios of Si:Ti were prepared using the sol-gel method. These materials were characterized using energy dispersive X-ray fluorescence, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, photoluminescence, Raman with Fourier transform infrared spectroscopy, and the specific surface area. The band gaps of materials were determined by diffuse reflectance spectra, and the values of 3.20 ± 0.01, 2.92 ± 0.02, and 2.85 ± 0.01 eV were obtained as a result of the proportional increases in the amount of Ti within the composite. The materials exhibit only the anatase (TiO2) crystalline phase and have crystalline domains ranging from 4 to 5 nm. The photodegradation process of methylene blue, royal blue GRL, and golden yellow GL dyes were studied with respect to their contact times, pH variations within the solution, and the variations in the dye concentration of the solution in response to only sunlight. The maximum amount of time for the mineralization of dyes was 90 min. The kinetics of the process follows an apparently first order model, in which the obtained rate constant values were 5.72 × 10-2 min-1 for methylene blue, 6.44 × 10-2min-1 for royal blue GRL, and 1.07 × 10-1min-1 for golden yellow.

Coopetitive advantage – How firms create and appropriate value by collaborating with their competitors

Collaboration between competing firms (coopetition) has emerged as an important issue forn business practice in many industries. Extant literature has examined coopetition on many levels of analysis, but lacks clarity in distinguishing it explicitly from cooperation between noncompeting organizations. Because of this, the performance implications of coopetition from the perspective of an individual firm are still ambiguous – some research suggests positive results whereas other studies suggest detrimental outcomes. The aim in this dissertation is to narrow these gaps by exploring how firms create and appropriate value through collaboration with their competitors. The dissertation is divided into two parts. The first part comprises an overview of the relevant literature, as well as the conclusions of the whole study, and the second part includes six research publications. Both qualitative and quantitative methodologies are utilized. The results suggest that coopetition embodies the distinctive logic of value creation and appropriation from the perspective of an individual firm, and thus differs in terms of performance implications from cooperation between non-competitors. The distinction comes from the fact that competitors have somewhat similar understanding, capabilities and interest related to certain markets, which is potentially both challenging and beneficial in terms of the individual firm’s competitiveness. It appears from the findings that there are distinctive firm-external and firm-specific factors affecting the success of a coopetition strategy. This study makes three main contributions. First, on the conceptual level it shows the distinction between coopetition and cooperation between non-rivals as a collaborative inter-organizational relationship. Secondly, it sets out a framework and propositions that enhance understanding of how value is created and appropriated in coopetition from the perspective of an individual firm. Thirdly, it offers empirical evidence of how coopetition affects firms’ innovation and market performance, and identifies the focal internal and external factors involved. In general terms, the thesis adds to our knowledge of how a firm can successfully utilize a coopetition strategy in its pursuit of improved performance.

Numerical modelling of small supersonic axial flow turbines

Supersonic axial turbine stages typically exhibit lower efficiencies than subsonic axial turbine stages. One reason for the lower efficiency is the occurrence of shock waves. With higher pressure ratios the flow inside the turbine becomes relatively easily supersonic if there is only one turbine stage. Supersonic axial turbines can be designed in smaller physical size compared to subsonic axial turbines of same power. This makes them good candidates for turbochargers in large diesel engines, where space can be a limiting factor. Also the production costs are lower for a supersonic axial turbine stage than for two subsonic stages. Since supersonic axial turbines are typically low reaction turbines, they also create lower axial forces to be compensated with bearings compared to high reaction turbines. The effect of changing the stator-rotor axial gap in a small high (rotational) speed supersonic axial flow turbine is studied in design and off-design conditions. Also the effect of using pulsatile mass flow at the supersonic stator inlet is studied. Five axial gaps (axial space between stator and rotor) are modeled using threedimensional computational fluid dynamics at the design and three axial gaps at the off-design conditions. Numerical reliability is studied in three independent studies. An additional measurement is made with the design turbine geometry at intermediate off-design conditions and is used to increase the reliability of the modelling. All numerical modelling is made with the Navier-Stokes solver Finflo employing Chien’s k ¡ ² turbulence model. The modelling of the turbine at the design and off-design conditions shows that the total-to-static efficiency of the turbine decreases when the axial gap is increased in both design and off-design conditions. The efficiency drops almost linearily at the off-design conditions, whereas the efficiency drop accelerates with increasing axial gap at the design conditions. The modelling of the turbine stator with pulsatile inlet flow reveals that the mass flow pulsation amplitude is decreased at the stator throat. The stator efficiency and pressure ratio have sinusoidal shapes as a function of time. A hysteresis-like behaviour is detected for stator efficiency and pressure ratio as a function of inlet mass flow, over one pulse period. This behaviour arises from the pulsatile inlet flow. It is important to have the smallest possible axial gap in the studied turbine type in order to maximize the efficiency. The results for the whole turbine can also be applied to some extent in similar turbines operating for example in space rocket engines. The use of a supersonic stator in a pulsatile inlet flow is shown to be possible.

Characterization of Citrus tristeza virus isolates from grapefruit (Citrus paradisi Macf.) accessions of Citrus Active Germplasm Bank

Citrus tristeza virus (CTV) isolates from 35 grapefruit accessions belonging to Citrus Active Germplasm Bank of the "Instituto Agronômico de Campinas" located at the "Centro APTA Citros Sylvio Moreira", Cordeirópolis, São Paulo state, Brazil, were characterized and evaluated through symptoms in the trees, biological indexing, immunological diagnosis with different monoclonal antibodies and SSCP analysis (single-strand conformation polymorphism) of the coat protein gene. Symptomatology indicated that, in general, the group of plants with smaller canopy volume and severe stem pitting differed significantly from the group that presented greater vegetative development and mild to moderate stem pitting. However, the isolates from most of the accessions induced mild reaction on Mexican lime. The serological evaluation through the DAS-ELISA using monoclonal antibodies did not reveal any association between virus titer in the plant tissue and symptoms. The reaction with different monoclonal antibodies and the distinct electrophoresis patterns obtained through SSCP showed that there is a high degree of diversity among the isolates that infect these grapefruit accessions. High complexity within the same isolate was also observed in the SSCP profiles. This finding indicates that the CTV isolates from these plants are a complex mixture of CTV haplotypes. Similar SSCP banding patterns were observed among some plants with strong stem pitting symptoms, and among some plants with weak or moderate stem pitting symptoms.

Magnetic and transport properties of LaMnO3+δ, La1-xCaxMnO3, La1-xCaxMn1-yFeyO3 and La1-xSrxMn1-yFeyO3

Interest to hole-doped mixed-valence manganite perovskites is connected to the ‘colossal’ magnetoresistance. This effect or huge drop of the resistivity, ρ, in external magnetic field, B, attains usually the maximum value near the ferromagnetic Curie temperature, TC. In this thesis are investigated conductivity mechanisms and magnetic properties of the manganite perovskite compounds LaMnO3+, La1-xCaxMnO3, La1-xCaxMn1-yFeyO3 and La1- xSrxMn1-yFeyO3. When the present work was started the key role of the phase separation and its influence on the properties of the colossal magnetoresistive materials were not clear. Our main results are based on temperature dependencies of the magnetoresistance and magnetothermopower, investigated in the temperature interval of 4.2 - 300 K in magnetic fields up to 10 T. The magnetization was studied in the same temperature range in weak (up to 0.1 T) magnetic fields. LaMnO3+δ is the parent compound for preparation of the hole-doped CMR materials. The dependences of such parameters as the Curie temperature, TC, the Coulomb gap, Δ, the rigid gap, γ, and the localization radius, a, on pressure, p, are observed in LaMnO3+δ. It has been established that the dependences above can be interpreted by increase of the electron bandwidth and decrease of the polaron potential well when p is increased. Generally, pressure stimulates delocalization of the electrons in LaMnO3+δ. Doping of LaMnO3 with Ca, leading to La1-xCaxMnO3, changes the Mn3+/Mn4+ ratio significantly and brings an additional disorder to the crystal lattice. Phase separation in a form of mixture of the ferromagnetic and the spin glass phases was observed and investigated in La1- xCaxMnO3 at x between 0 and 0.4. Influence of the replacement of Mn by Fe is studied in La0.7Ca0.3Mn1−yFeyO3 and La0.7Sr0.3Mn1−yFeyO3. Asymmetry of the soft Coulomb gap and of the rigid gap in the density of localized states, small shift of the centre of the gaps with respect to the Fermi level and cubic asymmetry of the density of states are obtained in La0.7Ca0.3Mn1−yFeyO3. Damping of TC with y is connected to breaking of the double-exchange interaction by doping with Fe, whereas the irreversibility and the critical behavior of the magnetic susceptibility are determined by the phase separation and the frustrated magnetic state of La0.7Sr0.3Mn1−yFeyO3.

Teaching mathematics and programming : new approaches with empirical evaluation

Programming and mathematics are core areas of computer science (CS) and consequently also important parts of CS education. Introductory instruction in these two topics is, however, not without problems. Studies show that CS students find programming difficult to learn and that teaching mathematical topics to CS novices is challenging. One reason for the latter is the disconnection between mathematics and programming found in many CS curricula, which results in students not seeing the relevance of the subject for their studies. In addition, reports indicate that students' mathematical capability and maturity levels are dropping. The challenges faced when teaching mathematics and programming at CS departments can also be traced back to gaps in students' prior education. In Finland the high school curriculum does not include CS as a subject; instead, focus is on learning to use the computer and its applications as tools. Similarly, many of the mathematics courses emphasize application of formulas, while logic, formalisms and proofs, which are important in CS, are avoided. Consequently, high school graduates are not well prepared for studies in CS. Motivated by these challenges, the goal of the present work is to describe new approaches to teaching mathematics and programming aimed at addressing these issues: Structured derivations is a logic-based approach to teaching mathematics, where formalisms and justifications are made explicit. The aim is to help students become better at communicating their reasoning using mathematical language and logical notation at the same time as they become more confident with formalisms. The Python programming language was originally designed with education in mind, and has a simple syntax compared to many other popular languages. The aim of using it in instruction is to address algorithms and their implementation in a way that allows focus to be put on learning algorithmic thinking and programming instead of on learning a complex syntax. Invariant based programming is a diagrammatic approach to developing programs that are correct by construction. The approach is based on elementary propositional and predicate logic, and makes explicit the underlying mathematical foundations of programming. The aim is also to show how mathematics in general, and logic in particular, can be used to create better programs.

Paineellisten rumpusuodinten kunnossapitostrategian kehittäminen ja implementointi

Tutkimuksen tavoitteena oli luoda UPM-Kymmene Oyj:n Kaukaan sellutehtaalle tuotannolliset näkökulmat huomioiva ja kunnossapitokustannukset optimoiva paineellisten rumpusuodinten kunnossapitostrategia. Paineelliset rumpusuotimet on sellutehtaan kuitulinjan keskeinen laiteryhmä, jonka vuosittaiset kunnossapitokustannukset ovat merkittävät. Tarkastelu työssä keskittyi paineellisen rumpusuotimen päätytiivistyksen kunnossapitostrategian kehittämiseen, koska päätytiivistys muodostaa laitteen vuosittaisista kustannuksista suurimman osan. Kunnossapitokustannusten optimointi suoritettiin strategisen johtamisen periaatteiden mukaisesti eri teknistaloudelliset näkökulmat huomioiden. Kunnossapidon toteutukselle määriteltiin tuotannon tavoitteet, jonka perusteella luotiin uusi kunnossapitostrategia. Työssä tehdyn tutkimuksen perusteella siirtymällä korjaavasta kunnossapidosta ehkäisevään kunnossapitoon, voidaan saavuttaa säästöjä kunnossapitokustannuksissa. Uuden strategian toteutumisen mahdollistamiseksi määriteltiin strategiset projektit, jotka käsittelivät muun muassa uusien tiivistemateriaalien käyttöönottoa, alajärjestelmien muutostöitä sekä toimintatapojen muutoksia. Strategian ja strategisten projektien toteutusta varten laadittiin kirjalliset dokumentit, joiden perusteella implementointi suoritetaan. Toimenpiteille määriteltiin vastuuhenkilöt ja toteutusajat, joiden mukaisesti eri organisaatiotasot toimivat. Strategia laadittiin seuraavalle kymmenelle vuodelle, mutta strategian toteutusta ja tuloksia on seurattava vuosittain. Muuttuvassa liiketoimintaympäristössä kunnossapidon optimitila ei ole staattinen, joten strategiaa on oltava valmis päivittämään. Aktiivisella ja suunnitelmallisella toiminnalla on mahdollista saavuttaa merkittäviä säästöjä tuotannon ja kunnossapidon näkökulmasta.

Usability of laser–arc hybrid welding processes in industrial applications

Metal industries producing thick sections have shown increasing interest in the laser–arc hybrid welding process because of its clear advantages compared with the individual processes of autogenous laser welding and arc welding. One major benefit of laser–arc hybrid welding is that joints with larger gaps can be welded with acceptable quality compared to autogenous laser welding. The laser-arc hybrid welding process has good potential to extend the field of applications of laser technology, and provide significant improvements in weld quality and process efficiency in manufacturing applications. The objective of this research is to present a parameter set-up for laser–arc hybrid welding processes, introduce a methodical comparison of the chosen parameters, and discuss how this technology may be adopted in industrial applications. The research describes the principles, means and applications of different types of laser–arc hybrid welding processes. Conducted experiment processing variables are presented and compared using an analytical model which can also be used for predictive simulations. The main argument in this thesis is that profound understanding of the advanced technology of laser-arc hybrid welding will help improve the productivity of welding in industrial applications. Based on a review of the current knowledge base, important areas for further research are also identified. This thesis consists of two parts. The first part introduces the research topic and discusses laser–arc hybrid welding by characterizing its mechanism and most important variables. The second part comprises four research papers elaborating on the performance of laser– arc hybrid welding in the joining of metals. The study uses quantitative and qualitative research methods which include in-depth, interpretive analyses of results from a number of research groups. In the interpretive analysis, the emphasis is placed on the relevance and usefulness of the investigative results drawn from other research publications. The results of this study contribute to research on laser–arc hybrid welding by increasing understanding of how old and new perspectives on laser–arc hybrid welding are evidenced in industry. The research methodology applied permits continued exploration of how laser–arc hybrid welding and various process factors influence the overall quality of the weld. Thestudy provides a good foundation for future research, creates improved awareness of the laser–arc hybrid welding process, and assists the metal industry to maximize welding productivity.

Evaluation of the throughfall and stemflow nutrient contents in mixed and pure plantations of Acacia mangium, Pseudosamenea guachapele and Eucalyptus grandis

The interception of the rainfall by the forest canopy has great relevance to the nutrient geochemistry cycle in low fertility tropical soils under native or cultivated forests. However, little is known about the modification of the rainfall water quality and hydrological balance after interception by the canopies of eucalyptus under pure and mixed plantations with leguminous species, in Brazil. Samples of rainfall (RF), throughfall (TF) and stemflow (SF) were collected and analyzed in pure plantations of mangium (nitrogen fixing tree -NFT), guachapele (NFT) and eucalyptus (non-nitrogen fixing tree -NNFT) and in a mixed stand of guachapele and eucalyptus in Seropédica, State of Rio de Janeiro, Brazil. Nine stemflow collectors (in selected trees) and nine pluviometers were randomly disposed under each stand and three pluviometers were used to measure the incident rainfall during 5.5 months. Mangium conveyed 33.4% of the total rainfall for its stem. An estimative based on corrections for the average annual precipitation (1213 mm) indicated that the rainfall's contribution to the nutrient input (kg ha-1) was about 8.42; 0.95; 19.04; 6.74; 4.72 and 8.71 kg ha-1 of N-NH4+, P, K+, Ca+2, Mg+2 and Na+, respectively. Throughfall provided the largest contributions compared to the stemflow nutrient input. The largest inputs of N-NH4+ (15.03 kg ha-1) and K+ (179.43 kg ha-1) were observed under the guachapele crown. Large amounts of Na+ denote a high influence of the sea. Mangium was the most adapted species to water competitiveness. Comparatively to pure stand of eucalyptus, the mixed plantation intensifies the N, Ca and Mg leaching by the canopy, while the inputs of K and P were lower under these plantations.

Tree structure and richness in an Atlantic Forest fragment: distance from anthropogenic and natural edges

Approximately 7.2% of the Atlantic rainforest remains in Brazil, with only 16% of this forest remaining in the State of Rio de Janeiro, all of it distributed in fragments. This forest fragmentation can produce biotic and abiotic differences between edges and the fragment interior. In this study, we compared the structure and richness of tree communities in three habitats - an anthropogenic edge (AE), a natural edge (NE) and the fragment interior (FI) - of a fragment of Atlantic forest in the State of Rio de Janeiro, Brazil (22°50'S and 42°28'W). One thousand and seventy-six trees with a diameter at breast height > 4.8 cm, belonging to 132 morphospecies and 39 families, were sampled in a total study area of 0.75 ha. NE had the greatest basal area and the trees in this habitat had the greatest diameter:height allometric coefficient, whereas AE had a lower richness and greater variation in the height of the first tree branch. Tree density, diameter, height and the proportion of standing dead trees did not differ among the habitats. There was marked heterogeneity among replicates within each habitat. These results indicate that the forest interior and the fragment edges (natural or anthropogenic) do not differ markedly considering the studied parameters. Other factors, such as the age from the edge, type of matrix and proximity of gaps, may play a more important role in plant community structure than the proximity from edges.