Browsing by Issue Date

Sort by: Order: Results:

Now showing items 1-20 of 1937
  • Heinonen, Jussi S.; Kurz, Mark D. (ELSEVIER BV, 2015)
    The massive outpourings of Karoo and Ferrar continental flood basalts (CFBs) ~180 Ma ago mark the initial Jurassic rifting stages of the Gondwana supercontinent. The origin and sources of these eruptions have been debated for decades, largely due to difficulties in defining their parental melt and mantle source characteristics. Recent findings of Fe- and Mg-rich dikes (depleted ferropicrite suite) from Vestfjella, western Dronning Maud Land, Antarctica, have shed light on the composition of the deep sub-Gondwanan mantle: these magmas have been connected to upper mantle sources presently sampled by the Southwest Indian Ocean mid-ocean ridge basalts (SWIR MORBs) or to high 3He/4He plume-entrained non-chondritic primitive mantle sources formed early in Earth’s history. In an attempt to determine their He isotopic composition and relative contributions from magmatic, cosmogenic, and radiogenic He sources, we performed in-vacuo stepwise crushing and melting analyses of olivine mineral separates, some of which were abraded to remove the outer layer. The best estimate for the mantle isotopic composition is given by a sample with the highest amount of He released (> 50%) during the first crushing step of an abraded coarse fraction. It has a 3He/4He of 7.03 ± 0.23 (2σ) times the atmospheric ratio (Ra), which is indistinguishable from those measured from SWIR MORBs (6.3‒7.3 Ra; source 3He/4He ~6.4–7.6 Ra at 180 Ma) and notably lower than in the most primitive lavas from the North Atlantic Igneous Province (up to 50 Ra), considered to represent the epitome magmas from non-chondritic primitive mantle sources. Previously published trace element and isotopic (Sr, Nd, and Pb) compositions do not suggest a direct genetic link to any modern hotspot of Indian or southern Atlantic Oceans. Although influence of a mantle plume cannot be ruled out, the high magma temperatures and SWIR MORB-like geochemistry of the suite are best explained by supercontinent insulation of a precursory Indian Ocean upper mantle source. Such a model is also supported by the majority of the recent studies on the structure, geochronology, and petrology of the Karoo CFBs.
  • Heinonen, Jussi S.; Jennings, Eleanor S.; Riley, Teal R. (ELSEVIER BV, 2015)
    Calculating reliable temperatures of Mg-rich magmas is problematic because melt composition and KD(Fe-Mg)ol-liq, the key parameters of many traditional thermometers, are difficult to constrain precisely. The recently developed Al-in-olivine thermometer [Coogan, L.A., Saunders, A.D., Wilson, R.N., 2014. Aluminum-in-olivine thermometry of primitive basalts: Evidence of an anomalously hot mantle source for large igneous provinces. Chemical Geology 368, 1–10] circumvents these problems by relying on the temperature-dependent exchange of Al between olivine and spinel crystallising in equilibrium with each other. This thermometer is used to re-evaluate the crystallisation temperatures of the most Mg-rich magma type identified from the Karoo large igneous province (LIP), known as the Vestfjella depleted ferropicrite suite. Previous temperature estimates for the suite were based on olivine-melt equilibria and indicated anomalously high crystallisation temperatures in excess of 1600 °C. We also present crystallisation temperatures for another Antarctic Karoo magma type, Group 3 dykes from Ahlmannryggen, which are derived from a pyroxene-rich mantle source. Our high-precision analysis of Al in olivine-spinel pairs indicate crystallisation temperatures from 1391±42 °C to 1481±35 °C for the Vestfjella depleted ferropicrite suite (Fo88–92) and from 1253±64 °C to 1303±40 °C for the Group 3 dykes (Fo79–82). Although the maximum temperature estimates for the former are over 100 °C lower than the previously presented estimates, they are still ~200 °C higher than those calculated for mid-ocean ridge basalts using the same method. Although exact mantle potential temperatures are difficult to estimate, the presented results support elevated sub-Gondwanan upper mantle temperatures (generated by a mantle plume or internal mantle heating) during the generation of the Karoo LIP.
  • Tenkanen, Henrikki Toivo Olavi; Salonen, Maria; Lattu, Matti Petteri; Toivonen, Tuuli Kaarina (PERGAMON, 2015)
    Accessibility and transportation possibilities are key factors influencing societal conditions and land use patterns in rural areas. Thus, information on the spatial patterns of accessibility and transportation can be of paramount importance in understanding regional differences in development, human livelihood and land use patterns. Analysing spatio-temporal transportation patterns is particularly challenging in areas where everyday transportation is based on unscheduled public transportation and a naturally controlled seasonal transportation network, such as rivers. Here, our aim is to provide information on the seasonal dynamics of riverine transportation and its effects on accessibility patterns in Peruvian Amazonia. We analysed riverine transportation speeds using a low-cost GPS-based riverboat observation system. Spatio-temporal accessibility patterns were generalised from the GPS-observations that were classified according to seasons into the high water season, intermediate season and low water season. We show that navigation along the rivers has a clear seasonal and directional (upstream/downstream) variation, which varies with different types of rivers based on channel morphology. In addition, we conducted interviews with local people to study their perceptions of the seasonal changes in navigation and the accuracy of transportation schedules. As the travel distances in Peruvian Amazonia are generally long, seasonal and directional differences have clear impacts on the overall accessibility patterns in the area and on the livelihoods of riverine inhabitants. Furthermore, the lack of clearly scheduled transportation causes considerable uncertainty about transportation options for local communities. The baseline information of the seasonal and directional variation of riverine transportation and travel speeds provided by our work is usable in further accessibility and livelihood analyses for Peruvian Amazonia, but it may also be useful in other areas relying on riverine transportation.
  • Bourdais, Gildas; Burdiak, Pawel; Gauthier, Adrien Guy Bernard; Nitsch, Lisette; Salojärvi, Jarkko Tapani; Rayapuram, Channabasavangowda; Idänheimo, Niina Johanna; Hunter, Kerri Alyssa; Kimura, Sachie; Merilo, Ebe; Vaattovaara, Aleksia Fanni Maria; Oracz, Krystyna; Kaufholdt, David; Pallon, Andres; Anggoro, Damar Tri; Glow, Dawid; Lowe, Jennifer; Zhou, Ji; Mohammadi, Omid; Puukko, Tuomas; Albert, Andreas; Lang, Hans; Ernst, Dieter; Kollist, Hannes; Brosche, Mikael Johan; Durner, Jörg; Borst, Jan Willem; Collinge, David B.; Karpinski, Stanislaw; Lyngkjaer, Michael F.; Robatzek, Silke; Wrzaczek, Michael Alois; Kangasjärvi, Jaakko Sakari (PUBLIC LIBRARY OF SCIENCE, 2015)
    Cysteine-rich receptor-like kinases (CRKs) are transmembrane proteins characterized by the presence of two domains of unknown function 26 (DUF26) in their ectodomain. The CRKs form one of the largest groups of receptor-like protein kinases in plants, but their biological functions have so far remained largely uncharacterized. We conducted a large-scale phenotyping approach of a nearly complete crk T-DNA insertion line collection showing that CRKs control important aspects of plant development and stress adaptation in response to biotic and abiotic stimuli in a non-redundant fashion. In particular, the analysis of reactive oxygen species (ROS)-related stress responses, such as regulation of the stomatal aperture, suggests that CRKs participate in ROS/redox signalling and sensing. CRKs play general and fine-tuning roles in the regulation of stomatal closure induced by microbial and abiotic cues. Despite their great number and high similarity, large-scale phenotyping identified specific functions in diverse processes for many CRKs and indicated that CRK2 and CRK5 play predominant roles in growth regulation and stress adaptation, respectively. As a whole, the CRKs contribute to specificity in ROS signalling. Individual CRKs control distinct responses in an antagonistic fashion suggesting future potential for using CRKs in genetic approaches to improve plant performance and stress tolerance.
  • Hartl, C.; Schmidt, Alexander; Heinrichs, Jochen; Seyfullah, Leyla; Schäfer, N.; Gröhn, Carsten; Rikkinen, Jouko Kalevi; Kaasalainen, Ulla Susanna (Copernicus, 2015)
    The fossil record of lichens is scarce and many putative fossil lichens do not show an actual physiological relationship between mycobionts and photobionts or a typical habit, and are therefore disputed. Amber has preserved a huge variety of organisms in microscopic fidelity, and so the study of amber fossils is promising for elucidating the fossil history of lichens. However, so far it has not been tested as to how amber inclusions of lichens are preserved regarding their internal characters, ultrastructure, and chemofossils. Here, we apply light microscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and Raman spectroscopy to an amber-preserved Eocene lichen in order to gain information about the preservation of the fossil. The lichen thallus displays lifelike tissue preservation including the upper and lower cortex, medulla, photobiont layer, apothecia, and soredia. SEM analysis revealed globular photobiont cells in contact with the fungal hyphae, as well as impressions of possible former crystals of lichen compounds. EDX analysis permitted the differentiation between halite and pyrite crystals inside the lichen which were likely formed during the later diagenesis of the amber piece. Raman spectroscopy revealed the preservation of organic compounds and a difference between the composition of the cortex and the medulla of the fossil.
  • Kohonen, Jukka; Corander, Jukka (TAYLOR & FRANCIS INC., 2015)
    An exponential-time exact algorithm is provided for the task of clustering n items of data into k clusters. Instead of seeking one partition, posterior probabilities are computed for summary statistics: the number of clusters, and pairwise co-occurrence. The method is based on subset convolution, and yields the posterior distribution for the number of clusters in O(n 3^n) operations, or O(n^3 2^n) using fast subset convolution. Pairwise co-occurrence probabilities are then obtained in O(n^3 2^n) operations. This is considerably faster than exhaustive enumeration of all partitions.
  • Tahko, Tuomas E. (OXFORD UNIVERSITY PRESS, 2015)
    Recent work on Natural Kind Essentialism has taken a deflationary turn. The assumptions about the grounds of essentialist truths concerning natural kinds familiar from the Kripke-Putnam framework are now considered questionable. The source of the problem, however, has not been sufficiently explicated. The paper focuses on the Twin Earth scenario and it will be demonstrated that the essentialist principle at its core (which I call IDENT) – necessarily, a sample of a chemical substance, A, is of the same kind as another sample, B, if and only if A and B have the same microstructure – must be re-evaluated. The Twin Earth scenario also assumes the falsity of another essentialist principle (which I call INST): necessarily, there is a 1:1 correlation between (all of) the chemical properties of a chemical substance and the microstructure of that substance. This assumption will be questioned, and it will be argued that, in fact, the best strategy for defending IDENT is to establish INST. The prospects for Natural Kind Essentialism and microstructural essentialism regarding chemical substances will be assessed with reference to recent work in the philosophy of chemistry. Finally, a weakened form of INST will be presented.
  • Di Minin, Enrico; Toivonen, Tuuli (2015)
    Aichi target 11 of the Convention of Biological Diversity promotes the expansion of the global protected area network to cover 17 percent of all terrestrial land and ­10 percent of coastal and marine areas by 2020 (www.cbd.int/sp/targets). At the recent World Parks Congress, organized by the International Union for Conservation of Nature (IUCN) in Sydney, Australia, 12 innovative approaches were promoted as part of the “Promise of Sydney” to help transform decisionmaking, policy, capacity, and financing for protected areas in the next decade (http://io.aibs.org/syd). The first of such approaches includes a list of 20 important recommendations to help reach conservation goals. Many of these ­recommendations are provided for ­single countries to take action individually. In addition, the final recommendation advocates that a more ambitious target of protection (50 percent global protection) should be promoted to more adequately conserve biodiversity. Both points are problematic: recent research shows that facilitating international collaboration among countries is crucial to identifying and implementing a well-connected system of protected areas that can better represent threatened biodiversity, and setting unrealistic and politically challenging global protection targets is unneeded. This Viewpoint presents three main themes of the recommendations that would benefit from greater emphasis and the promotion of the importance of international collaborations.
  • Vismantic 
    Xiao, Ping; Linkola, Simo Matias (2015)
    This paper presents Vismantic, a semi-automatic system generating proposals of visual composition (visual ideas) in order to express specific meanings. It implements a process of developing visual solutions from ‘what to say’ to ‘how to say’, which requires both conceptual and visual creativity. In particular, Vismantic extends previous work on using conceptual knowledge to find diverse visual representations of abstract concepts, with the capacity of combining two images in three ways, including juxtaposition, replacement and fusion. In an informal evaluation consisting of five communication tasks, Vismantic demonstrated the potential of producing a number of expressive and diverse ideas, among which many are surprising. Our analysis of the generated images confirms that visual meaning making is a subtle interaction between all elements in a picture, for which Vismantic demands more visual semantic knowledge, higher image analysis and synthesis skills, and the ability of interpreting composed images, in order to deliver more ideas that make sense.
  • Kneifel, Stefan; von Lerber, Annakaisa; Tiira, Jussi; Moisseev, Dmitri; Kollias, Pavlos; Leinonen, Jussi (American Geophysical Union, 2015)
    Recently published studies of triple-frequency radar observations of snowfall have demonstrated that naturally occurring snowflakes exhibit scattering signatures that are in some cases consistent with spheroidal particle models and in others can only be explained by complex aggregates. Until recently, no in situ observations have been available to investigate links between microphysical snowfall properties and their scattering properties. In this study, we investigate for the first time relations between collocated ground-based triple-frequency observations with in situ measurements of snowfall at the ground. The three analyzed snowfall cases obtained during a recent field campaign in Finland cover light to moderate snowfall rates with transitions from heavily rimed snow to open-structured, low-density snowflakes. The observed triple-frequency signatures agree well with the previously published findings from airborne radar observations. A rich spatiotemporal structure of triple-frequency observations throughout the cloud is observed during the three cases, which often seems to be related to riming and aggregation zones within the cloud. The comparison of triple-frequency signatures from the lowest altitudes with the ground-based in situ measurements reveals that in the presence of large (>5 mm) snow aggregates, a bending away in the triple-frequency space from the curve of classical spheroid scattering models is always observed. Rimed particles appear along an almost horizontal line in the triple-frequency space, which was not observed before. Overall, the three case studies indicate a close connection of triple-frequency signatures and snow particle structure, bulk snowfall density, and characteristic size of the particle size distribution.
  • Kaasalainen, Ulla; Olsson, Sanna Elina; Rikkinen, Jouko Kalevi (Public Library of Science, 2015)
    The group I intron interrupting the tRNALeu UAA gene (trnL) is present in most cyanobacterial genomes as well as in the plastids of many eukaryotic algae and all green plants. In lichen symbiotic Nostoc, the P6b stem-loop of trnL intron always involves one of two different repeat motifs, either Class I or Class II, both with unresolved evolutionary histories. Here we attempt to resolve the complex evolution of the two different trnL P6b region types. Our analysis indicates that the Class II repeat motif most likely appeared first and that independent and unidirectional shifts to the Class I motif have since taken place repeatedly. In addition, we compare our results with those obtained with other genetic markers and find strong evidence of recombination in the 16S rRNA gene, a marker widely used in phylogenetic studies on Bacteria. The congruence of the different genetic markers is successfully evaluated with the recently published software Saguaro, which has not previously been utilized in comparable studies.
  • Ahonen, Pertti Pellervo (ResearchGate, 2015)
    The purpose of this article is an examination informed by neo-institutional political and related research on two foremost aspects of institutionalization, performance and legitimation. Political research published by scholars of the extended Baltic region by late May r 2013 comprises the study topic. The article considers political research in four selected subfields: general political science, international relations/world politics, public policy, and public administration/public management. The results indicate that Denmark and Norway are “great powers” in the region, with a strong presence in strongly legitimate publication arenas of political research. Looking further at the performance suggested by publications and citations to these, Sweden and Finland stand out no less than Denmark and Norway, and Estonia and Lithuania also receive visibility. Examining performance with the bibliometric “h” index suggests that “size matters”, which accentuates German achievements, although Norway, Denmark and Sweden continue to stand out despite their relatively small population size.
  • Tynkkynen, Veli-Pekka (Helsingin yliopisto, Aleksanteri-instituutti, 2015)
    Through its use of the Arctic, Russia tries to fortify the idea that it is a global Energy Superpower
  • Kaasalainen, Ulla; Heinrichs, Jochen; Krings, Michael; Myllys, Leena; Grabenhorst, Heinrich; Rikkinen, Jouko; Schmidt, Alexander R. (Public Library of Science, 2015)
    One of the most important issues in molecular dating studies concerns the incorporation of reliable fossil taxa into the phylogenies reconstructed from DNA sequence variation in extant taxa. Lichens are symbiotic associations between fungi and algae and/or cyanobacteria. Several lichen fossils have been used as minimum age constraints in recent studies concerning the diversification of the Ascomycota. Recent evolutionary studies of Lecanoromycetes, an almost exclusively lichen-forming class in the Ascomycota, have utilized the Eocene amber inclusion Alectoria succinic as a minimum age constraint. However, a re-investigation of the type material revealed that this inclusion in fact represents poorly preserved plant remains, most probably of a root. Consequently, this fossil cannot be used as evidence of the presence of the genus Alectoria (Parmeliaceae, Lecanorales) or any other lichens in the Paleogene. However, newly discovered inclusions from Paleogene Baltic and Bitterfeld amber verify that alectorioid morphologies in lichens were in existence by the Paleogene. The new fossils represent either a lineage within the alectorioid group or belong to the genus Oropogon.
  • Eranti, Veikko Oskari; Lonkila, Markku Kalle (FIRST MONDAY EDITORIAL GROUP, 2015)
    In this paper we study social aspects of using the Like button for purposes of impression management, identity construction, and maintenance of social ties online. On the theoretical level our investigation combines Goffman’s notion of face-work with concepts of social network analysis, shedding light on what we dub ‘nano-level’ interaction and sociality on social networking sites. Our data come from a 2013 classroom survey in which 26 Finnish university students were asked about their motives for and ways of using the Like button. Our results show that though the Like button was designed to allow users to express their positive evaluations of the contents of Facebook posts, comments, and pictures, it was in actual fact used for a wide variety of purposes, from dating efforts to conversation regulation and maintenance of social ties. Our results also reveal that the networked Facebook audience affects the users’ liking behavior, and that users reflect their liking based on previous likes.
  • Norrby, Catrin; Wide, Camilla; Lindström, Jan Krister; Nilsson, Jenny (ELSEVIER BV, 2015)
    This article investigates how interpersonal relationships are expressed in medical consultations. In particular, we focus on how modes of address are used in the two national varieties of Swedish: Sweden Swedish and Finland Swedish, with the aim to compare the pragmatic routines in the two varieties. Thus the study contributes to the field of variational pragmatics, where national varieties of pluricentric languages are recognised as important research objects. Address practices are analysed in two comparable corpora of video recordings from Sweden and Finland using both a quantitative and a qualitative CA-inspired method. There are several differences between the data sets: the Sweden-Swedish data are characterised by exclusive use of the informal T pronoun (du ‘you’) and an overall higher frequency of direct address compared to the Finland-Swedish data. In some medical consultations in the latter Finland-Swedish data the formal V pronoun (ni) is used. The qualitative analysis confirms these differences and the tendency is that the Sweden-Swedish medical consultations are more informal than the Finland-Swedish ones, which are characterised by more formality and maintenance of social distance between the interlocutors. The different pragmatic orientations at the micro level of communication can also be related to socio-cultural preferences at the macro level in society – the development towards greater informality and intimate language is more pronounced in Sweden than in Finland.
  • Salo, Johanna; Andersson, Aino Maria Alice; Mikkola, Raimo Olavi; Kredics, Laszlo; Viljanen, Martti; Salkinoja-Salonen, Mirja Sinikka (2015)
    Penicillium expansum was identified as a major contaminant in indoor air, settled dust and materials of several buildings connected to indoor air related health complaints. This fungus emitted large quantities of exudates when cultivated on laboratory media. The exudates proved toxic towards four different mammalian test cells up to 10000 fold dilution. Toxins identified by LC-MS/MS were communesins and chaetoglobosin. Air dispersal of the toxic exudates was investigated with an experimental set-up where natural convection was generated by temperature gradient. It was found that the exudate with the contained toxins became airborne transported from the warmer surface to the colder surface. The results thus demonstrate transportation of microbially produced toxic substances across the air space. The role of liquid emissions from indoor molds represents a novel mechanism for human exposure in mold contaminated buildings. In this paper we report that vapor condensed from the indoor air of building affected with molds Aspergillus versicolor, Aspergillus calidoustus and Penicillium expansum contained substances that were acutely toxic when exposed to mammalian cells in vitro. The results encourage further study of condensed indoor water vapor as a tool to assess the presence of airborne substances with possible adverse health effects.
  • Lönnqvist, Jan-Erik; Hennig-Schmidt, Heike; Walkowitz, Gari (Public Library of Science, 2015)
  • Siljander, Pia Riitta-Maria; Yáñez-Mó, Maria (Co-Action Publishing, 2015)
    In the past decade, extracellular vesicles (EVs) have been recognized as potent vehicles of intercellular communication, both in prokaryotes and eukaryotes. This is due to their capacity to transfer proteins, lipids and nucleic acids, thereby influencing various physiological and pathological functions of both recipient and parent cells.While intensive investigation has targeted the role of EVs in different pathological processes, for example, in cancer and autoimmune diseases, the EV-mediated maintenance of homeostasis and the regulation of physiological functions have remained less explored. Here, we provide a comprehensive overview of the current understanding of the physiological roles of EVs, which has been written by crowd-sourcing, drawing on the unique EV expertise of academia-based scientists, clinicians and industry based in 27 European countries, the United States and Australia. This review is intended to be of relevance to both researchers already working on EV biology and to newcomers who will encounter this universal cell biological system. Therefore, here we address the molecular contents and functions of EVs in various tissues and body fluids from cell systems to organs. We also review the physiological mechanisms of EVs in bacteria, lower eukaryotes and plants to highlight the functional uniformity of this emerging communication system.