Browsing by Subject "FIELD"

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  • Kassamakov, Ivan; Lecler, Sylvain; Nolvi, Anton; Leong-Hoi, Audrey; Montgomery, Paul; Haeggström, Edward (2017)
    We present quantitative three dimensional images of grooves on a writable Blu-ray Disc based on a single objective Mirau type interferometric microscope, enhanced with a microsphere which is considered as a photonic nanojet source. Along the optical axis the resolution of this microsphere assisted interferometry system is a few nanometers while the lateral resolution is around 112 nm. To understand the physical phenomena involved in this kind of imaging we have modelled the interaction between the photonic jet and the complex disc surface. Agreement between simulation and experimental results is demonstrated. We underline that although the ability of the microsphere to generate a photonic nanojet does not alone explain the resolution of the interferometer, the nanojet can be used to try to understand the imaging process. To partly explain the lateral super-resolution, the potential role of coherence is illustrated. The presented modality may have a large impact on many fields from bio-medicine to nanotechnology.
  • Kallio, Galina (2020)
    Questions of value are central to understanding alternative practices of food exchange. This study introduces a practice-based approach to value that challenges the dominant views, which capture value as either an input for or an outcome of practices of exchange (value as values, standards, or prices). Building on a longitudinal ethnographic study on food collectives, I show how value, rather than residing in something that people share, or in something that objects have, is an ideal target that continuously unfolds and evolves in action. I found that people organized their food collectives around pursuing three kinds of value-ideals, namely good food, good price and good community. These value-ideals became reproduced in food collectives through what I identified as valuing modes, by which people evaluated the goodness of food, prices and community. My analysis revealed that, while participating in food collectives in order to pursue their value-ideals, people were likely to have differing reasons for pursuing them and tended to attach different meanings to the same value-ideal. I argue that understanding how value as an ideal target is reproduced through assessing and assigning value (valuing modes) is essential in further explorations of the formation of value and in better understanding the dynamics of organizing alternative practices of food exchange.
  • Mammarella, I.; Werle, P.; Pihlatie, M.; Eugster, W.; Haapanala, S.; Kiese, R.; Markkanen, T.; Rannik, U.; Vesala, T. (2010)
  • Vardoulaki, E.; Andrade, E. F. Jimenez; Karim, A.; Novak, M.; Leslie, S. K.; Tisanic, K.; Smolcic, V.; Schinnerer, E.; Sargent, M. T.; Bondi, M.; Zamorani, G.; Magnelli, B.; Bertoldi, F.; Ruiz, N. Herrera; Mooley, K. P.; Delhaize, J.; Myers, S. T.; Marchesi, S.; Koekemoer, A. M.; Gozaliasl, G.; Finoguenov, A.; Middleberg, E.; Ciliegi, P. (2019)
    Context. Given the unprecedented depth achieved in current large radio surveys, we are starting to probe populations of radio sources that have not been studied in the past. However, identifying and categorising these objects, differing in size, shape and physical properties, is becoming a more difficult task. Aims. In this data paper we present and characterise the multi-component radio sources identified in the VLA-COSMOS Large Project at 3 GHz (0.75 arcsec resolution, 2.3 mu Jy beam(-1) rms), i.e. the radio sources which are composed of two or more radio blobs. Methods. The classification of objects into multi-components was done by visual inspection of 351 of the brightest and most extended blobs from a sample of 10,899 blobs identified by the automatic code BLOBCAT. For that purpose we used multi-wavelength information of the field, such as the 1.4 GHz VLA-COSMOS data and the Ultra Deep Survey with the VISTA telescope (UltraVISTA) stacked mosaic available for COSMOS. Results. We have identified 67 multi-component radio sources at 3 GHz: 58 sources with active galactic nucleus (AGN) powered radio emission and nine star-forming galaxies. We report eight new detections that were not observed by the VLA-COSMOS Large Project at 1.4 GHz, due to the slightly larger area coverage at 3 GHz. The increased spatial resolution of 0.75 arcsec has allowed us to resolve (and isolate) multiple emission peaks of 28 extended radio sources not identified in the 1.4 GHz VLA-COSMOS map. We report the multi-frequency flux densities (324 MHz, 325 MHz, 1.4 GHz & 3 GHz), star formation rates, and stellar masses of these objects. We find that multi-component objects at 3 GHz VLA-COSMOS inhabit mainly massive galaxies (>10(10.5)M(circle dot)). The majority of the multi-component AGN lie below the main sequence of star-forming galaxies (SFGs), in the green valley and the quiescent region. Furthermore, we provide detailed descriptions of the objects and find that amongst the AGN there are two head-tail, ten corelobe, nine wide-angle-tail (WAT), eight double-double or Z-/X-shaped, three bent-tail radio sources, and 26 symmetric sources, while amongst the SFGs we find the only star-forming ring seen in radio emission in COSMOS. Additionally, we report a large number (32 out of 58) of disturbed/bent multi-component AGN, 18 of which do not lie within X-ray groups in COSMOS (redshift range 0.08 Conclusion. The high angular resolution and sensitivity of the 3 GHz VLA-COSMOS data set give us the opportunity to identify peculiar radio structures and sub-structures of multi-component objects, and relate them to physical phenomena such as AGN or star-forming galaxies. This study illustrates the complexity of the mu Jy radio-source population; at the sensitivity and resolution of 3 GHz VLA-COSMOS, the radio structures of AGN and SFG both emitting radio continuum emission, become comparable in the absence of clear, symmetrical jets. Thus, disentangling the AGN and SFG contributions using solely radio observations can be misleading in a number of cases. This has implications for future surveys, such as those done by square kilometre array (SKA) and precursors, which will identify hundreds of thousands of multi-component objects.
  • Reichenau, Tim G.; Korres, Wolfgang; Schmidt, Marius; Graf, Alexander; Welp, Gerhard; Meyer, Nele; Stadler, Anja; Brogi, Cosimo; Schneider, Karl (2020)
    The development and validation of hydroecological land-surface models to simulate agricultural areas require extensive data on weather, soil properties, agricultural management, and vegetation states and fluxes. However, these comprehensive data are rarely available since measurement, quality control, documentation, and compilation of the different data types are costly in terms of time and money. Here, we present a comprehensive dataset, which was collected at four agricultural sites within the Rur catchment in western Germany in the framework of the Transregional Collaborative Research Centre 32 (TR32) "Patterns in Soil-Vegetation-Atmosphere Systems: Monitoring, Modeling and Data Assimilation". Vegetation-related data comprise fresh and dry biomass (green and brown, predominantly per organ), plant height, green and brown leaf area index, phenological development state, nitrogen and carbon content (overall > 17 000 entries), and masses of harvest residues and regrowth of vegetation after harvest or before planting of the main crop (> 250 entries). Vegetation data including LAI were collected in frequencies of 1 to 3 weeks in the years 2015 until 2017, mostly during overflights of the Sentinel 1 and Radarsat 2 satellites. In addition, fluxes of carbon, energy, and water (> 180 000 half-hourly records) measured using the eddy covariance technique are included. Three flux time series have simultaneous data from two different heights. Data on agricultural management include sowing and harvest dates as well as information on cultivation, fertilization, and agrochemicals (27 management periods). The dataset also includes gap-filled weather data (> 200 000 hourly records) and soil parameters (particle size distributions, carbon and nitrogen content; > 800 records). These data can also be useful for development and validation of remote-sensing products. The dataset is hosted at the TR32 database (, last access: 29 September 2020) and has the DOI (Reichenau et al., 2020).
  • Ruotsalainen, Juho; Hujanen, Jaana; Villi, Mikko (2019)
    As pioneers of new ideas and practices, many entrepreneurial journalists spearhead the change of journalism towards hybridity. By applying appraisal theory, this article examines a hybrid of objectivity and dialogue in daily news articles by five entrepreneurial journalism outlets – Axios, MustRead, National Observer, The Skimm and the Voice of San Diego. For comparative purposes, a dataset from three legacy media outlets was also analysed. The results show that the entrepreneurial journalism outlets employ journalistic dialogue in otherwise stylistically objective news texts notably more often than do legacy media outlets. Dialogic registers provide subtle, non-partisan assessments of events and issues and make the news more informal. Such a hybrid form of journalism serves the functions of sense-making, establishing an interpersonal connection between ‘private’ audiences and ‘public’ news, and connecting journalism with fields outside of its core. By doing so, the hybrid journalism of entrepreneurial journalists offers a distinctive vision of the futures of news journalism.
  • Baryshnikov, Glib; Valiev, Rashid R.; Nasibullin, Rinat T.; Sundholm, Dage; Kurten, Theo; Ågren, Hans (2020)
    The recently synthesized cyclo[18]carbon molecule has been characterized in a number of studies by calculating electronic, spectroscopic, and mechanical properties. However, cyclo[18] carbon is only one member of the class of cyclo[n]carbons-standalone carbon allotrope representatives. Many of the larger members of this class of molecules have not been thoroughly investigated. In this work, we calculate the magnetically induced current density of cyclo[n]carbons in order to elucidate how electron delocalization and aromatic properties change with the size of the molecular ring (n), where n is an even number between 6 and 100. We find that the Hiickel rules for aromaticity (4k + 2) and antiaromaticity (4k) become degenerate for large C-n rings (n > 50), which can be understood as a transition from a delocalized electronic structure to a nonaromatic structure with localized current density fluxes in the triple bonds. Actually, the calculations suggest that cyclo[n]carbons with n > 50 are nonaromatic cyclic polyalkynes. The influence of the amount of nonlocal exchange and the asymptotic behavior of the exchange-correlation potential of the employed density functionals on the strength of the magnetically induced ring current and the aromatic character of the large cyclo[n]carbons is also discussed.
  • Malkamäki, Aapo Erkki Matias; Sharma, Vivek (2019)
    Mitochondrial cytochrome c oxidase couples the reduction of oxygen to proton pumping. Despite an overall good understanding of its molecular mechanism, the role of cardiolipin in protein function is not understood. Here, we have studied the cardiolipin-protein interactions in a dynamic context by means of atomistic molecular dynamics simulations performed on the entire structure of monomeric and dimeric forms of the enzyme. Several microseconds of simulation data reveal that the crystallographic cardiolipin molecules that glue two monomers together bind weakly in hybrid and single-component lipid bilayers and dissociate rapidly. Atomistic simulations performed in the absence of tightly bound cardiolipin molecules strongly perturb the structural integrity of subunits III and Vila, thereby highlighting an indispensable nature of lipid-protein interactions in enzyme function such as proton uptake and oxygen channeling. Our results demonstrate the strength of molecular simulations in providing direct atomic description of lipid-protein processes that are difficult to achieve experimentally.
  • Pihajoki, Pauli; Mannerkoski, Matias; Johansson, Peter H. (2019)
    Interpolation of data represented in curvilinear coordinates and possibly having some non-trivial, typically Riemannian or semi-Riemannian geometry is a ubiquitous task in all of physics. In this work, we present a covariant generalization of the barycentric coordinates and the barycentric interpolation method for Riemannian and semi-Riemannian spaces of arbitrary dimension. We show that our new method preserves the linear accuracy property of barycentric interpolation in a coordinate-invariant sense. In addition, we show how the method can be used to interpolate constrained quantities so that the given constraint is automatically respected. We showcase the method with two astrophysics related examples situated in the curved Kerr space-time. The first problem is interpolating a locally constant vector field, in which case curvature effects are expected to be maximally important. The second example is a general relativistic magnetohydrodynamics simulation of a turbulent accretion flow around a black hole, wherein high intrinsic variability is expected to be at least as important as curvature effects.
  • Simpanen, Suvi; Dahl, Mari; Gerlach, Magdalena; Mikkonen, Anu; Malk, Vuokko; Mikola, Juha; Romantschuk, Martin (2016)
    The use of in situ techniques in soil remediation is still rare in Finland and most other European countries due to the uncertainty of the effectiveness of the techniques especially in cold regions and also due to their potential side effects on the environment. In this study, we compared the biostimulation, chemical oxidation, and natural attenuation treatments in natural conditions and pilot scale during a 16-month experiment. A real fuel spill accident was used as a model for experiment setup and soil contamination. We found that biostimulation significantly decreased the contaminant leachate into the water, including also the non-aqueous phase liquid (NAPL). The total NAPL leachate was 19 % lower in the biostimulation treatment that in the untreated soil and 34 % lower in the biostimulation than oxidation treatment. Soil bacterial growth and community changes were first observed due to the increased carbon content via oil amendment and later due to the enhanced nutrient content via biostimulation. Overall, the most effective treatment for fresh contaminated soil was biostimulation, which enhanced the biodegradation of easily available oil in the mobile phase and consequently reduced contaminant leakage through the soil. The chemical oxidation did not enhance soil cleanup and resulted in the mobilization of contaminants. Our results suggest that biostimulation can decrease or even prevent oil migration in recently contaminated areas and can thus be considered as a potentially safe in situ treatment also in groundwater areas.
  • Gädda, Akiko; Ott, Jennifer; Karadzhinova-Ferrer, Aneliya; Golovleva, Maria; Kalliokoski, Matti; Winkler, Alexander; Luukka, Panja; Härkönen, Jaakko (2019)
    The suitability of two low-temperature dielectric passivation layer processes for the fabrication of Cadmium Telluride (CdTe) X-ray detectors has been investigated. The CdTe crystals with a size of (10 10 1) mm were coated with sputtered aluminum nitride (AlN) or with aluminum oxide (AlO) grown by the atomic layer deposition (ALD) method. The metallization contacts of the detectors were made by titanium tungsten (TiW) and gold (Au) metal sputtering depositions. The pad detector structures were patterned with proximity-contactless photolithography techniques followed by lift-off patterning of the electrodes. The detector properties were characterized at room temperature by Transient Current Technique (TCT) measurements. The obtained results were compared and verified by numerical TCAD simulations of the detector response. Our results indicate that higher signal charge was collected from samples with AlO. Furthermore, no significant laser light induced signal decay by CdTe material polarization was observed within order of 30 min of continuous illumination.
  • Vainio, Annukka; Varho, Vilja; Tapio, Petri; Pulkka, Anna; Paloniemi, Riikka (2019)
    Achieving a sustainable energy transition is crucial for mitigating climate change. Citizens' acceptance of the transition is important for it to succeed. We explored citizens' images of the future energy forms and energy system in Finland, and the drivers of a sustainable energy transition. The data gathered with an online questionnaire targeting an adult population 17–75 years of age (N = 1012) were analysed with exploratory factor analysis and multiple linear regression. Four dimensions of future energy forms were identified: next-generation renewables, fossil energy, bioenergy, and established renewable vs. nuclear energy. Four dimensions of the future energy system were also identified: renewing the energy market, domestic power, small-scale producers, and consumer awareness. Five transition drivers were likewise identified: mainstreaming renewable energy, international actors, individual actions, changing values and economy, and emancipatory change. Mainstreaming renewable energy emerged as the key driver of transition, followed by individual actions. Generally, the sustainable energy transition was strongly supported by citizens' images, but different socio-economic groups preferred somewhat different images. Thus, the diversity of consumers' and citizens’ roles in the transition needs to be acknowledged and encouraged in legitimate national energy policies.
  • Kaps, Manfred; Grittner, Ulrike; Jungehuelsing, Gerhard; Tatlisumak, Turgut; Kessler, Christoph; Schmidt, Reinhold; Putaala, Jukka; Norrving, Bo; Rolfs, Arndt; Tanislav, Christian; Sifap1 Investigators (2014)
  • Dumitru, Adrian; Mäntysaari, Heikki; Paatelainen, Risto (2021)
    Color charge correlators provide fundamental information about the proton structure. In this Letter, we evaluate numerically two-point color charge correlations in a proton on the light cone including the next-to-leading order corrections due to emission or exchange of a perturbative gluon. The non-perturbative valence quark structure of the proton is modelled in a way consistent with high-x proton structure data. Our results show that the correlator exhibits startlingly non-trivial behavior at large momentum transfer or central impact parameters, and that the color charge correlation depends not only on the impact parameter but also on the relative transverse momentum of the two gluon probes and their relative angle. Furthermore, from the two-point color charge correlator, we compute the dipole scattering amplitude. Its azimuthal dependence differs significantly from a impact parameter dependent McLerran-Venugopalan model based on geometry. Our results also provide initial conditions for Balitsky-Kovchegov evolution of the dipole scattering amplitude. These initial conditions depend not only on the impact parameter and dipole size vectors, but also on their relative angle and on the light-cone momentum fraction x in the target. (C) 2021 The Author(s). Published by Elsevier B.V.
  • Akhavan-Tafti, M.; Palmroth, M.; Slavin, J. A.; Battarbee, M.; Ganse, U.; Grandin, M.; Le, G.; Gershman, D. J.; Eastwood, J. P.; Stawarz, J. E. (2020)
    The Vlasiator hybrid-Vlasov code was developed to investigate global magnetospheric dynamics at ion-kinetic scales. Here we focus on the role of magnetic reconnection in the formation and evolution of magnetic islands at the low-latitude magnetopause, under southward interplanetary magnetic field conditions. The simulation results indicate that (1) the magnetic reconnection ion kinetics, including the Earthward pointing Larmor electric field on the magnetospheric side of an X-point and anisotropic ion distributions, are well-captured by Vlasiator, thus enabling the study of reconnection-driven magnetic island evolution processes, (2) magnetic islands evolve due to continuous reconnection at adjacent X-points, "coalescence" which refers to the merging of neighboring islands to create a larger island, "erosion" during which an island loses magnetic flux due to reconnection, and "division" which involves the splitting of an island into smaller islands, and (3) continuous reconnection at adjacent X-points is the dominant source of magnetic flux and plasma to the outer layers of magnetic islands resulting in cross-sectional growth rates up to + 0.3 R-E(2)/min. The simulation results are compared to the Magnetospheric Multiscale (MMS) measurements of a chain of ion-scale flux transfer events (FTEs) sandwiched between two dominant X-lines. The MMS measurements similarly reveal (1) anisotropic ion populations and (2) normalized reconnection rate similar to 0.18, in agreement with theory and the Vlasiator predictions. Based on the simulation results and the MMS measurements, it is estimated that the observed ion-scale FTEs may grow Earth-sized within similar to 10 min, which is comparable to the average transport time for FTEs formed in the subsolar region to the high-latitude magnetopause. Future simulations shall revisit reconnection-driven island evolution processes with improved spatial resolutions.
  • Guryanov, Ivan; Korzhikov-Vlakh, Viktor; Bhattacharya, Madhushree; Biondi, Barbara; Masiero, Giulia; Formaggio, Fernando; Tennikova, Tatiana; Urtti, Arto (2021)
    The design of efficient vascular endothelial growth factor (VEGF) inhibitors is a high-priority research area aimed at the treatment of pathological angiogenesis. Among other compounds, v114* has been identified as a potent VEGF-binding peptide. In order to improve the affinity to VEGF, we built a conformational constrain in its structure. To this aim, C-alpha-tetrasubstituted amino acid Aib was introduced into the N-terminal tail, peptide loop, or C-terminal helix. NMR studies confirmed the stabilization of the helical conformation in proximity to the Aib residue. We found that the induction of the N-terminal helical structure or stabilization of the C-terminal helix can noticeably increase the peptide affinity to the VEGF. These peptides efficiently inhibited VEGF-stimulated cell proliferation as well. The insertion of the non-proteinogenic Aib residue significantly enhanced the stability of the peptides in the vitreous environment. Thus, these Aib-containing peptides are promising candidates for the design of VEGF inhibitors with improved properties.
  • Kwiatek, Grzegorz; Saarno, Tero; Ader, Thomas; Bluemle, Felix; Bohnhoff, Marco; Chendorain, Michael; Dresen, Georg; Heikkinen, Pekka; Kukkonen, Ilmo; Leary, Peter; Leonhardt, Maria; Malin, Peter; Martínez-Garzón, Patricia; Passmore, Kevin; Passmore, Paul; Valenzuela, Sergio; Wollin, Christopher (2019)
    We show that near–real-time seismic monitoring of fluid injection allowed control of induced earthquakes during the stimulation of a 6.1-km-deep geothermal well near Helsinki, Finland. A total of 18,160 m3 of fresh water was pumped into crystalline rocks over 49 days in June to July 2018. Seismic monitoring was performed with a 24-station borehole seismometer network. Using near–real-time information on induced-earthquake rates, locations, magnitudes, and evolution of seismic and hydraulic energy, pumping was either stopped or varied—in the latter case, between well-head pressures of 60 and 90 MPa and flow rates of 400 and 800 liters/min. This procedure avoided the nucleation of a project-stopping magnitude MW 2.0 induced earthquake, a limit set by local authorities. Our results suggest a possible physics-based approach to controlling stimulation-induced seismicity in geothermal projects.
  • Linker, Jon A.; Heinemann, Stephan G.; Temmer, Manuela; Owens, Mathew J.; Caplan, Ronald M.; Arge, Charles N.; Asvestari, Eleanna; Delouille, Veronique; Downs, Cooper; Hofmeister, Stefan J.; Jebaraj, Immanuel C.; Madjarska, Maria S.; Pinto, Rui F.; Pomoell, Jens; Samara, Evangelia; Scolini, Camilla; Vrsnak, Bojan (2021)
    Many scientists use coronal hole (CH) detections to infer open magnetic flux. Detection techniques differ in the areas that they assign as open, and may obtain different values for the open magnetic flux. We characterize the uncertainties of these methods, by applying six different detection methods to deduce the area and open flux of a near-disk center CH observed on 2010 September 19, and applying a single method to five different EUV filtergrams for this CH. Open flux was calculated using five different magnetic maps. The standard deviation (interpreted as the uncertainty) in the open flux estimate for this CH approximate to 26%. However, including the variability of different magnetic data sources, this uncertainty almost doubles to 45%. We use two of the methods to characterize the area and open flux for all CHs in this time period. We find that the open flux is greatly underestimated compared to values inferred from in situ measurements (by 2.2-4 times). We also test our detection techniques on simulated emission images from a thermodynamic MHD model of the solar corona. We find that the methods overestimate the area and open flux in the simulated CH, but the average error in the flux is only about 7%. The full-Sun detections on the simulated corona underestimate the model open flux, but by factors well below what is needed to account for the missing flux in the observations. Under-detection of open flux in coronal holes likely contributes to the recognized deficit in solar open flux, but is unlikely to resolve it.
  • Tiurev, Konstantin; Kuopanportti, Pekko; Möttönen, Mikko (2019)
    We theoretically demonstrate that a pair of Dirac monopoles with opposite synthetic charges can be created within a single spin-1 Bose-Einstein condensate by steering the spin degrees of freedom by external magnetic fields. Although the net synthetic magnetic charge of this configuration vanishes, both the monopole and the antimonopole are accompanied by vortex filaments carrying opposite angular momenta. Such a Dirac dipole can be realized experimentally by imprinting a spin texture with a nonlinear magnetic field generated by a pair of coils in a modified Helmholtz configuration. We also investigate the case where the initial state for the dipole-creation procedure is pierced by a quantized vortex line with a winding number kappa. It is shown that if kappa = -1, the resulting monopole and antimonopole lie along the core of a singly quantized vortex whose sign is reversed at the locations of the monopoles. For kappa = -2, the monopole and antimonopole are connected by a vortex line segment carrying two quanta of angular momentum, and hence the dipole as a whole is an isolated configuration. In addition, we simulate the long-time evolution of the dipoles in the magnetic field used to create them. For kappa = 0, each of the semi-infinite doubly quantized vortices splits into two singly quantized vortices, as in the case of a single Dirac monopole. For kappa = -1 and kappa = -2, the initial vortices deform into a vortex with a kink and a vortex ring, respectively.
  • Appelgren, Ester; Linden, Carl-Gustav (2020)
    The combined set of skills needed for producing data journalism (e.g., investigative journalism methods, programming, knowledge in statistics, data management, statistical reporting, and design) challenges the understanding of what competences a journalist needs and the boundaries for the tasks journalists perform. Scholars denote external actors with these types of knowledge as interlopers or actors at the periphery of journalism. In this study, we follow two Swedish digital native data journalism start-ups operating in the Nordics from when they were founded in 2012 to 2019. Although the start-ups have been successful in news journalism over the years and acted as drivers for change in Nordic news innovation, they also have a presence in sectors other than journalism. This qualitative case study, which is based on interviews over time with the start-up founders and a qualitative analysis of blog posts written by the employees at the two start-ups, tells a story of journalists working at the periphery of legacy media, at least temporarily forced to leave journalism behind yet successfully using journalistic thinking outside of journalistic contexts.