Browsing by Subject "spatial"

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  • Blyth, Pascale-L. (Science Direct, 2020)
    Energy Research Social Science 70 (2020), 101574
    Arguably the most powerful artifact of the 20th century, the private car brought profound spatial, social, and cultural changes, as well as wide-ranging mobility justice implications. Autonomous mobility technologies, with the power to supplant part or all of the action of the driver by collecting and processing large quantities of fine grained data, promise to shift power away from users to engineers and create new important spatial and social implications for mobility justice, of which little are known. This research draws from Foucauldian conceptualizations adapted for the study of geographies of power to investigate how autonomous mobility technology may diagram spatial rationalities and moralities into the built environment. To that effect, it draws from 30 interviews of intermediaries in Finland–a country actively pursuing a transition to automated and shared mobility as part of an ICT-driven innovation policy. Examining autonomous mobility through a Foucauldian lens helps highlight the complex power relations it affords–in terms of changes in social structure and infrastructure, and social justice. By shedding light on how technology may structure the built environment, the Foucauldian perspective shows itself to be a valuable tool for planning and policymaking, providing insight into how autonomous mobility (in)justice may be assembled.
  • Camarena‐Gómez, María Teresa; Ruiz‐González, Clara; Piiparinen, Jonna; Lipsewers, Tobias; Sobrino, Cristina; Logares, Ramiro; Spilling, Kristian (American Society of Limnology and Oceanography, 2021)
    Limnology and Oceanography 66: 1, 255-271
    In parts of the Baltic Sea, the phytoplankton spring bloom communities, commonly dominated by diatoms, are shifting toward the co-occurrence of diatoms and dinoflagellates. Although phytoplankton are known to shape the composition and function of associated bacterioplankton communities, the potential bacterial responses to such a decrease of diatoms are unknown. Here we explored the changes in bacterial communities and heterotrophic production during the spring bloom in four consecutive spring blooms across several sub-basins of the Baltic Sea and related them to changes in environmental variables and in phytoplankton community structure. The taxonomic structure of bacterioplankton assemblages was partially explained by salinity and temperature but also linked to the phytoplankton community. Higher carbon biomass of the diatoms Achnanthes taeniata, Skeletonema marinoi, Thalassiosira levanderi, and Chaetoceros spp. was associated with more diverse bacterial communities dominated by copiotrophic bacteria (Flavobacteriia, Gammaproteobacteria, and Betaproteobacteria) and higher bacterial production. During dinoflagellate dominance, bacterial production was low and bacterial communities were dominated by Alphaproteobacteria, mainly SAR11. Our results suggest that increases in dinoflagellate abundance during the spring bloom will largely affect the structuring and functioning of the associated bacterial communities. This could decrease pelagic remineralization of organic matter and possibly affect the bacterial grazers communities.
  • Bhattacharjee, Joy; Marttila, Hannu; Haghighi, Ali Torabi; Saarimaa, Miia; Tolvanen, Anne; Lepistö, Ahti; Futter, Martyn N.; Kløve, Bjørn (American Society of Civil Engineers, 2021)
    Journal of Irrigation and Drainage Engineering, 147(4), 04021006
    Spatiotemporal information on historical peatland drainage is needed to relate past land use to observed changes in catchment hydrology. Comprehensive knowledge of historical development of peatland management is largely unknown at the catchment scale. Aerial photos and light detection and ranging (LIDAR) data enlarge the possibilities for identifying past peatland drainage patterns. Here, our objectives are (1) to develop techniques for semiautomatically mapping the location of ditch networks in peat-dominated catchments using aerial photos and LIDAR data, and (2) to generate time series of drainage networks. Our approaches provide open-access techniques to systematically map ditches in peat-dominated catchments through time. We focused on the algorithm in such a way that we can identify the ditch networks from raw aerial images and LIDAR data based on the modification of multiple filters and number of threshold values. Such data are needed to relate spatiotemporal drainage patterns to observed changes in many northern rivers. We demonstrate our approach using data from the Simojoki River catchment (3,160  km2) in northern Finland. The catchment is dominated by forests and peatlands that were almost all drained after 1960. For two representative locations in cultivated peatland (downstream) and peatland forest (upstream) areas of the catchment; we found total ditch length density (km/km2), estimated from aerial images and LIDAR data based on our proposed algorithm, to have varied from 2% to 50% compared with the monitored ditch length available from the National Land survey of Finland (NLSF) in 2018. A different pattern of source variation in ditch network density was observed for whole-catchment estimates and for the available drained-peatland database from Natural Resources Institute Finland (LUKE). Despite such differences, no significant differences were found using the nonparametric Mann-Whitney U test with a 0.05 significance level based on the samples of pixel-identified ditches between (1) aerial images and NLSF vector files and (2) LIDAR data and NLSF vector files.
  • Liu, Xing (Svenska handelshögskolan, 2012)
    Economics and Society – 249
    The integration of European agriculture into the world economy has also accelerated price interaction between member states and the rest of the world during last decades. Consequently, the fluctuation in world market prices was more quickly transmitted to European member states, including Finland. Increasing price uncertainty and price volatility in agricultural products became more evident. The openness of regional agriculture such as EU and Finnish to the world is irreversible, and the international community needs timely and differentiated information on the situation in different places in order to respond appropriately. The theme of this dissertation concerns the properties of price linkage of agricultural commodities across space during the last decades. Such properties include hedging issues, price transmission and marketing margin in the agricultural commodity market. By understanding the issues, agricultural market participants, including farmers, processors, industries, consumers and policy makers can benefit from insights into these issues either in order to assess past actions and decisions or to derive guidelines for future action. In summary, this dissertation consists of 5 independent articles. Article 1 presents a case study on optimal hedging on Finnish wheat under both price and yield risks. The result shows that the forward contract might not be the best hedging tool for the farmers in Finland where the yield volatility per unit is bigger than price volatility. Article 2 presents an efficiency test of the CPO futures market in Malaysia for European participants using the cointegration technique. The results suggest that the futures market in Malaysia is not efficient for European participants, which indicates that they should be more cautious in using the hedging strategy in this futures market. Articles 3 focuses on the price transmission of the Finnish food market at vertical level, and Article 4 investigates horizontal price transmission of the Finnish meat market towards the European market in both symmetric and asymmetric ways. The result from Article 3 implies that the Finnish market is characterized by buyer power according to the measure of Lloyd et al. (2009). The result from Article 4 detects that the Finnish meat sector is integrated with EU benchmark countries symmetrically or asymmetrically. Moreover, the degree of integration and speed of adjustment of Finnish pork and beef towards the EU market are proved in different level. Article 5 presents an inventory model to investigate the relationship between price volatility and the inventory in the global wheat market. The results reveal that there is only a short-term significant relationship between price volatility and the inventory.
  • Alahuhta, Janne; Rosbakh, Sergey; Chepinoga, Victor; Heino, Jani (Springer Link, 2020)
    Aquatic Sciences 82 2 (2020)
    We investigated whether environmental filtering or dispersal-related factors mostly drive helophyte and hydrophyte species richness and community composition in 93 lakes situated in Baikal Siberia. Using partial linear regression and partial redundancy analysis, we studied (1) what are the relative roles of environmental variables, dispersal variables, spatial processes and region identity (i.e., river basins) in explaining variation in the species richness and species composition of helophytes and hydrophytes across 93 Siberian lakes, and (2) what are the differences in the most important explanatory variables driving community variation in helophytes versus hydrophytes? We found that, for both species richness and species composition, environmental variables clearly explained most variation for both plant groups, followed by region identity and dispersal-related variables. Spatial variables were significant only for the species composition of hydrophytes. Nutrient-salinity index, a proxy for habitat trophic-salinity status, was by far the most significant environmental determinant of helophytes and hydrophytes. Our results indicate that environmental factors explained the most variation in both species richness and species composition of helophytes and hydrophytes. Nevertheless, dispersal-related variables (i.e. spatial and dispersal) were also influential but less important than environmental factors. Furthermore, the dispersal-related variables were more important for hydrophytes than for helophytes. Most brackish permanent lakes were mostly located in the steppe biomes of southern Transbaikalia. This characteristic along with the oldest age, the largest distances to both river and settlements and the lowest temperatures in the study region distinguished them from freshwater, drained and more nutrient-rich floodplain lakes.
  • Nyman, Petra (Helsingfors universitet, 2005)
    According to some models of working memory, verbal and spatial material is processed in separate systems. However, there are task environments, such as multimedia, which typically contains both verbal and spatial material. An interesting question is how these two separate systems co-operate during the use of multimedia. In this experiment, recall of words and locations was studied. Twelve participants were presented with five different conditions, of which two were verbal, two were spatial and one was a combined task. The verbal tasks were serial recall of nine words. The words were either presented in the center of the screen or in different spatial locations. The spatial task was a computerized version of the Corsi Blocks Task, in which serial recall of nine spatial locations was required. The locations were marked with a string of the letter “X”, or with a word. In the combined task participants had to recall a series of nine words and their spatial locations in the correct order. The results showed that words were recalled equally well whether presented in the center of the screen, or in different spatial locations or whether recall of their spatial locations was required. On the contrary, recall of the spatial locations was impaired if verbal material had to be recalled simultaneously. These results imply that verbal and spatial materials are processed separately and the maintenance of spatial material is more sensitive to disruption than the maintenance of verbal material. The research method and the results can be applied when navigation in web-based environments is studied. In complex web-based environments, too heavy a load on the user’s working memory may cause spatial confusion, which leads to the problem of getting lost in the web-based environment.
  • Vanhatalo, Jarno; Foster, Scott D.; Hosack, Geoffrey R. (2021)
    The categorization of multidimensional data into clusters is a common task in statistics. Many applications of clustering, including the majority of tasks in ecology, use data that is inherently spatial and is often also temporal. However, spatiotemporal dependence is typically ignored when clustering multivariate data. We present a finite mixture model for spatial and spatiotemporal clustering that incorporates spatial and spatiotemporal autocorrelation by including appropriate Gaussian processes (GP) into a model for the mixing proportions. We also allow for flexible and semiparametric dependence on environmental covariates, once again using GPs. We propose to use Bayesian inference through three tiers of approximate methods: a Laplace approximation that allows efficient analysis of large datasets, and both partial and full Markov chain Monte Carlo (MCMC) approaches that improve accuracy at the cost of increased computational time. Comparison of the methods shows that the Laplace approximation is a useful alternative to the MCMC methods. A decadal analysis of 253 species of teleost fish from 854 samples collected along the biodiverse northwestern continental shelf of Australia between 1986 and 1997 shows the added clarity provided by accounting for spatial autocorrelation. For these data, the temporal dependence is comparatively small, which is an important finding given the changing human pressures over this time.