SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Ojala Antti) "

Sökning: WFRF:(Ojala Antti)

  • Resultat 1-10 av 21
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Alenius, Teija, et al. (författare)
  • The environment they lived in: anthropogenic changes in local and regional vegetation composition in eastern Fennoscandia during the Neolithic
  • 2020
  • Ingår i: Vegetation History and Archaeobotany. - : Springer Science and Business Media LLC. - 0939-6314 .- 1617-6278. ; 30, s. 489-506
  • Tidskriftsartikel (refereegranskat)abstract
    • Understanding about regional versus local changes in vegetation is critical in answering archaeological questions, in particular at a time when humans are assumed to have caused higher disturbances at local scales rather than regional scales; this is the case during the Neolithic. The aim of this paper is to assess the impact of Neolithic land use on regional and local vegetation dynamics, plant composition and disturbance processes (e.g. fire) in eastern Fennoscandia. We apply the Landscape Reconstruction Algorithm (LRA) to high-resolution pollen records from three lacustrine sediment cores that cover the Neolithic period. We calculate changes in vegetation composition and the rate of plant compositional change. Fire dynamics are estimated as an indicator of land use, although fire can result from both natural and anthropogenic disturbances. Our results show that during the Early Neolithic, changes were mainly driven by natural and climate-induced factors and vegetation composition and fire activity were similar at both regional and local scales. From ca. 4000 bc onwards, trends in vegetation and fire dynamics start to differ between regional and local scales. This is due to local land uses that are overshadowed at the regional scale by climate-induced factors. The use of the LOVE model in pollen analyses is therefore very useful to highlight local land uses that are not visible by using REVEALS.
  •  
2.
  • Giesecke, Thomas, et al. (författare)
  • The effect of past changes in inter-annual temperature variability on tree distribution limits
  • 2010
  • Ingår i: Journal of Biogeography. - : Wiley. - 1365-2699 .- 0305-0270. ; 37:7, s. 1394-1405
  • Tidskriftsartikel (refereegranskat)abstract
    • Aim The northern limits of temperate broadleaved species in Fennoscanndia are controlled by their requirements for summer warmth for successful regeneration and growth as well as by the detrimental effects of winter cold on plant tissue. However, occurrences of meteorological conditions with detrimental effects on individual species are rare events rather than a reflection of average conditions. We explore the effect of changes in inter-annual temperature variability on the abundances of the tree species Tilia cordata, Quercus robur and Ulmus glabra near their distribution limits using a process-based model of ecosystem dynamics. Location A site in central Sweden and a site in southern Finland were used as examples for the ecotone between boreal and temperate forests in Fennoscandia. The Finnish site was selected because of the availability of varve-thickness data. Methods The dynamic vegetation model LPJ-GUESS was run with four scenarios of inter-annual temperature forcing for the last 10,000 years. In one scenario the variability in the thickness of summer and winter varves from the annually laminated lake in Finland was used as a proxy for past inter-annual temperature variability. Two scenarios were devised to explore systematically the effect of stepwise changes in the variance and shape parameter of a probability distribution. All variability scenarios were run both with and without the long-term trend in Holocene temperature change predicted by an atmospheric general circulation model. Results Directional changes in inter-annual temperature variability have significant effects on simulated tree distribution limits through time. Variations in inter-annual temperature variability alone are shown to alter vegetation composition by magnitudes similar to the magnitude of changes driven by variation in mean temperatures. Main conclusions The varve data indicate that inter-annual climate variability has changed in the past. The model results show that past changes in species abundance can be explained by changes in the inter-annual variability of climate parameters as well as by mean climate. Because inter-annual climatic variability is predicted to change in the future, this component of climate change should be taken into account both when making projections of future plant distributions and when interpreting vegetation history.
  •  
3.
  • Helmens, Karin F., et al. (författare)
  • Warm summers and rich biotic communities during N-Hemisphere deglaciation
  • 2018
  • Ingår i: Global and Planetary Change. - : Elsevier BV. - 0921-8181 .- 1872-6364. ; 167, s. 61-73
  • Tidskriftsartikel (refereegranskat)abstract
    • Detailed studies on fossil remains of plants or animals in glacial lake sediments are rare. As a result, environmental conditions right at the moment of deglaciation of the large N-Hemisphere ice-sheets remain largely unknown. Here we study three deglacial phases of the Fennoscandian Ice Sheet as a unique, repeated element in a long sediment record preserved at Soldl in northern Finland. We summarize extensive multi-proxy data (diatoms, phytoliths, chironomids, pollen, spores, non-pollen palynomorphs, macrofossils, lithology, loss-on-ignition, C/N) obtained on glacial lake sediments dated to the early Holocene (ca. 10 kyr BP), early MIS 3 (ca. 50 kyr BP) and early MIS 5a (ca. 80 kyr BP). In contrast to the common view of an unproductive ice-marginal environment, our study reconstructs rich ecosystems both in the glacial lake and along the shores with forest on recently deglaciated land. Higher than present-day summer temperatures are reconstructed based on a large variety of aquatic taxa. Rich biota developed due to the insolation-induced postglacial warming and high nutrient levels, the latter resulting from erosion of fresh bedrock and sediment, leaching of surface soils, decay of plant material under shallow water conditions, and sudden decreases in lake volume. Aquatic communities responded quickly to deglaciation and warm summers and reflect boreal conditions, in contrast to the terrestrial ecosystem which responded with some delay probably due to time required for slow soil formation processes. Birch forest is reconstructed upon deglaciation of the large LGM ice-sheet and shrub tundra following the probably faster melting smaller MIS 4 and MIS 5b ice-sheets. Our study shows that glacial lake sediments can provide valuable palaeo-environmental data, that aquatic biota and terrestrial vegetation rapidly accommodated to new environmental conditions during deglaciation, and that glacial lake ecosystems, and the carbon stored in their sediments, should be included in earth system modeling.
  •  
4.
  • Johnson, Mark D., 1954, et al. (författare)
  • Unraveling Scandinavian geomorphology: the LiDAR revolution
  • 2015
  • Ingår i: GFF. - : Informa UK Limited. - 1103-5897 .- 2000-0863. ; 137:4, s. 245-251
  • Tidskriftsartikel (refereegranskat)abstract
    • In the observational sciences, technical advances are often followed by dramatic increases in scientific discoveries and improved theory. Leuwenhoek’s microscope and Galileo’s telescope gave us a “better look” at the microworld and the cosmos, which led to revolutions of past paradigms. In geomorphology and landscape analysis, similar advances have accompanied new maps and new mapping techniques. The first accurate globes, where the puzzle-piece fit of the southern continents was quickly noticed, were soon followed by the first mention of what would be continental drift. The first topographic maps were accompanied by similar shifts in thinking. For example, accurate topographic maps of the western US brought about the realization that even in arid regions, fluvial erosion can be the dominant landscaping force. Aerial photography provided a similar advance in observation, mapping and understanding. Satellite imagery of the Earth and other planets has dramatically revealed the geomorphic processes operating in inaccessible places, for example meteor impacts, volcanism and the importance of eolian and fluvial processes. Recent observations of Pluto and Mars attest to this fact. Satellite imagery also led to a revolution in glacial geomorphology by providing continent-wide images of features heretofore unnoticed, for example the palimpsest flow indicators of the Laurentide Ice Sheet (Boulton & Clark 1990). In the 90s, the production of digital elevation models (DEMs) and the development of geographic information system (GIS) tools allowed for new highly quantitative analysis of landscapes. The advent of LiDAR (Light Detection and Ranging) technology is poised to provide a similar rapid advance in observations and the potential for significant advances in geomorphic theory. We see that the ever increasing use of LiDAR technology is creating a similar leap forward in geomorphology, and this issuie celebrates that.
  •  
5.
  •  
6.
  •  
7.
  • Kreiser, Patrick, et al. (författare)
  • A Historical Investigation of the Strategic Process within Family Firms
  • 2006
  • Ingår i: Journal of Management History. - 1355-252X .- 1758-776X. ; 12:1, s. 100-114
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose of this paper: The primary purpose of this paper was to perform an in-depth analysis of the strategic process that occurs within family firms.Design/methodology/approach: This study analyzed the historical development of the growth strategies of five family firms in the United States, Finland, and Sweden.Findings: The results of this study suggest that family firms typically adopt conservative strategies in the early part of their life cycle. During their formative years, family firms often implement financially conservative strategies and place an emphasis on maintaining tight control of the strategic decision-making process within the family unit. However, the competitive pressures experienced by family firms over time often force these companies to embrace a more entrepreneurial posture during the latter stages of their life cycle.Research Implications: The stage in the company life cycle plays an important role in determining the strategic behavior of family firms. Future research aimed at replicating the results of this study may help shed further light on the strategic process that occurs within family firms.Practical Implications: Although the firms examined in this study were from various cultures, their strategic development over time was very similar. This tentatively suggests that the evolution of the strategic process that occurs within family firms may be generalizable across cultures.What is original/value of paper: Our findings indicate that there may be an important distinction between family firms and entrepreneurial organizations. That is, all family firms are not necessarily entrepreneurial, especially early on in their company life cycle.Paper Type: Research paperKey Words: Family Firms, Pulp and Paper Industry, Entrepreneurship, United States, Sweden, Finland
  •  
8.
  •  
9.
  • Lappalainen, Hanna K., et al. (författare)
  • Pan-Eurasian Experiment (PEEX) : towards a holistic understanding of the feedbacks and interactions in the land-atmosphere-ocean-society continuum in the northern Eurasian region
  • 2016
  • Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 16:22, s. 14421-14461
  • Tidskriftsartikel (refereegranskat)abstract
    • The northern Eurasian regions and Arctic Ocean will very likely undergo substantial changes during the next decades. The Arctic-boreal natural environments play a crucial role in the global climate via albedo change, carbon sources and sinks as well as atmospheric aerosol production from biogenic volatile organic compounds. Furthermore, it is expected that global trade activities, demographic movement, and use of natural resources will be increasing in the Arctic regions. There is a need for a novel research approach, which not only identifies and tackles the relevant multi-disciplinary research questions, but also is able to make a holistic system analysis of the expected feedbacks. In this paper, we introduce the research agenda of the Pan-Eurasian Experiment (PEEX), a multi-scale, multi-disciplinary and international program started in 2012 (https://www.atm.helsinki.fi/peex/). PEEX sets a research approach by which large-scale research topics are investigated from a system perspective and which aims to fill the key gaps in our understanding of the feedbacks and interactions between the land-atmosphereaquatic-society continuum in the northern Eurasian region. We introduce here the state of the art for the key topics in the PEEX research agenda and present the future prospects of the research, which we see relevant in this context.
  •  
10.
  • Löfgren, Kent, 1966-, et al. (författare)
  • Meeting the Challenges of Generational Change in the Teaching Profession : Towards a European Model for Intergenerational Teacher Collaboration
  • 2013
  • Ingår i: Educational Research eJournal. - : Educational Research e-Journal (EREJ). - 2254-0385. ; 2:2, s. 107-119
  • Tidskriftsartikel (refereegranskat)abstract
    • In a European-wide effort to improve the professional development of teachers, the 2AgePro project was conducted from November 2008 to October 2010. One of its goals was to develop and test different forms of intergenerational teacher collaboration among junior and senior teachers in primary and secondary schools. Another aim was to utilise the results from these pilots, which were conducted in the Czech Republic, Finland, Germany, the Netherlands, and Sweden, to create a model for intergenerational collaboration that could be used in any national or cultural setting. This article reports on the national pilots and proposes a European model for intergenerational collaboration for teachers.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-10 av 21
Typ av publikation
tidskriftsartikel (14)
konferensbidrag (4)
bokkapitel (3)
Typ av innehåll
refereegranskat (14)
övrigt vetenskapligt/konstnärligt (6)
populärvet., debatt m.m. (1)
Författare/redaktör
Ojala, Antti (5)
Alenius, Teija (2)
Giesecke, Thomas (2)
Melander, Anders (2)
Miller, Paul (2)
Peltola, Pasi (2)
visa fler...
Seppa, Heikki (2)
Luoto, Miska (1)
Shvidenko, Anatoly (1)
Hansson, Hans-Christ ... (1)
Muscheler, Raimund (1)
Fischer, Frank (1)
Joffe, Roberts (1)
Åström, Mats E., 196 ... (1)
Åström, Mats E. (1)
Alekseychik, Pavel (1)
Marquer, Laurent (1)
Molinari, Chiara (1)
Heikkilä, Maija (1)
Helmens, Karin F (1)
Sykes, Martin (1)
Kurten, Theo (1)
Laaksonen, Ari (1)
Petaja, Tuukka (1)
Sipila, Mikko (1)
Viisanen, Yrjo (1)
Kulmala, Markku (1)
Augustsson, Anna (1)
Chalov, Sergey (1)
Risberg, Jan (1)
Bauer, Tobias, Assoc ... (1)
Sandgren, Per (1)
Snowball, Ian (1)
Snowball, Ian, 1963- (1)
Mattila, Jussi (1)
Hogmalm, Johan, 1979 (1)
Andreae, Meinrat O. (1)
Kerminen, Veli-Matti (1)
de Leeuw, Gerrit (1)
Mikhailov, Eugene (1)
Kukkonen, Ilmo (1)
Juhola, Sirkku (1)
Saarinen, Timo (1)
Lihavainen, Heikki (1)
Sun, Junying (1)
Asmi, Eija (1)
Makshtas, Alexander (1)
Luoto, Tomi P. (1)
Tynkkynen, Veli-Pekk ... (1)
Johnson, Mark D., 19 ... (1)
visa färre...
Lärosäte
Jönköping University (7)
Lunds universitet (5)
Göteborgs universitet (2)
Uppsala universitet (2)
Luleå tekniska universitet (2)
Stockholms universitet (2)
visa fler...
Linnéuniversitetet (2)
Umeå universitet (1)
Sveriges Lantbruksuniversitet (1)
visa färre...
Språk
Engelska (21)
Forskningsämne (UKÄ/SCB)
Naturvetenskap (12)
Samhällsvetenskap (8)
Teknik (1)
Humaniora (1)

År

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy