Articles

Recent Submissions

  • Schönach, Paula (Routledge, 2016)
  • Dmitriev, Vasily; Lupovka, Valery; Gritsevich, Maria (Elsevier Scientific Publ. Co, 2015)
    Recently, there has been a worldwide proliferation of instruments and networks dedicated to observing meteors, including airborne and future space-based monitoring systems. There has been a corresponding rapid rise in high quality data accumulating annually. In this paper, we present a method embodied in the open-source software program "Meteor Toolkit", which can effectively and accurately process these data in an automated mode and discover the pre-impact orbit and possibly the origin or parent body of a meteoroid or asteroid. The required input parameters are the topocentric pre-atmospheric velocity vector and the coordinates of the atmospheric entry point of the meteoroid, i.e. the beginning point of visual path of a meteor, in an Earth centered-Earth fixed coordinate system, the International Terrestrial Reference Frame (ITRF). Our method is based on strict coordinate transformation from the ITRF to an inertial reference frame and on numerical integration of the equations of motion for a perturbed two-body problem. Basic accelerations perturbing a meteoroid's orbit and their influence on the orbital elements are also studied and demonstrated. Our method is then compared with several published studies that utilized variations of a traditional analytical technique, the zenith attraction method, which corrects for the direction of the meteor's trajectory and its apparent velocity due to Earth's gravity. We then demonstrate the proposed technique on new observational data obtained from the Finnish Fireball Network (FFN) as well as on simulated data. In addition, we propose a method of analysis of error propagation, based on general rule of covariance transformation. (C) 2015 Published by Elsevier Ltd.
  • Holopainen, Mika Antero (Kirjastotieteen ja informatiikan yhdistys, 2016)
  • Kisdi, Eva; Geritz, Stefanus; Boldin, Barbara (Elsevier Scientific Publ. Co, 2013)
  • Havu, Katri Annikki (Addleton Academic Publishers, 2016)
  • Leppäranta, Matti; Lindgren, Elisa; Arvola, Lauri (Cambridge University Press, 2016)
    Thermodynamics of a seasonal supraglacial lake were examined based on field data from three summers. At maximum, the lake body consisted of an upper layer with thin ice on top, and a lower layer with slush, hard ice and sediment at the bottom. Sublimation from the upper ice surface averaged to 0.7 mm d(-1), and melting in the ice interior averaged to 9.1 mm d(-1) during summer. Albedo was on average 0.6 and light attenuation coefficient was similar to 1 m(-1). Averaged over December and January, and over 3 different years, we found that the net solar heating was 137 W m(-2), while the losses averaged to 62 W m(-2) for the longwave radiation, 16 Wm(-2) for the sensible heat flux, 24 W m(-2) for the latent heat flux and 3 W m(-2) for the bottom flux. The depth scale is determined by the light attenuation distance and thermal diffusion coefficient, and the net liquid water volume ranged from 0.5 to 1.0 m in different years. The potential winter growth is more than summer melting, and thus the lake freezes up completely in winter in the present climate.
  • Boldin, Barbara; Kisdi, Eva (Wiley-Blackwell, 2012)
  • Saarnio, Elisa Maria; Pekkinen, Minna Helena; Itkonen, Suvi Tuulikki; Kemi, Virpi Elina; Karp, Heini Johanna; Kärkkäinen, Merja Ulla Margareetta; Mäkitie, Outimaija Sinikka; Lamberg-Allardt, Christel Johanna Emilia (2016)
  • Boldin, Barbara; Kisdi, Eva (Springer, 2016)
    Evolutionary suicide is a riveting phenomenon in which adaptive evolution drives a viable population to extinction. Gyllenberg and Parvinen (Bull Math Biol 63(5):981-993, 2001) showed that, in a wide class of deterministic population models, a discontinuous transition to extinction is a necessary condition for evolutionary suicide. An implicit assumption of their proof is that the invasion fitness of a rare strategy is well-defined also in the extinction state of the population. Epidemic models with frequency-dependent incidence, which are often used to model the spread of sexually transmitted infections or the dynamics of infectious diseases within herds, violate this assumption. In these models, evolutionary suicide can occur through a non-catastrophic bifurcation whereby pathogen adaptation leads to a continuous decline of host (and consequently pathogen) population size to zero. Evolutionary suicide of pathogens with frequency-dependent transmission can occur in two ways, with pathogen strains evolving either higher or lower virulence.
  • Dahal, Karna; Niemelä, Jari Kalevi (MDPI, 2016)
    Carbon neutrality represents one climate strategy adopted by many cities, including the city of Helsinki and the Helsinki metropolitan area in Finland. This study examines initiatives adopted by the Helsinki metropolitan area aimed at reducing energy-related carbon emissions and achieving carbon neutrality through future actions. Various sectorial energy consumption rates per year and carbon emissions from various sectors within the city of Helsinki and the metropolitan area were extracted from an online database and re-calculated (in GWh, MWh/inhabitant and MtCO(2)e, KtCO(2)e/inhabitant). We employed a backcasting scenario method to explore the various carbon reduction measures in the Helsinki metropolitan area. About 96% of the emissions produced in the Helsinki metropolitan area are energy-based. District heating represents the primary source of emissions, followed by transportation and electricity consumption, respectively. We also found that accomplishing the carbon reduction strategies of the Helsinki metropolitan area by 2050 remains challenging. Technological advancement for clean and renewable energy sources, smart policies and raising awareness resulting in behavioral changes greatly affect carbon reduction actions. Thus, strong political commitments are also required to formulate and implement stringent climate actions
  • Maasalo, K.; Fontell, T.; Wessman, Jaana; Aronen, E. T. (BioMed Central Ltd, 2016)
    Background: Few studies have examined the associations between sleep, mood and behaviour in young children in the early stages of developing psychopathology. The purpose here was to examine the association of emotional problems, especially mood, with family and child characteristics, sleep and behavioural problems in 4-12 year-old children. Methods: The sample was population-based and included 1714 children. Parents filled in the Strengths and Difficulties Questionnaire and a background questionnaire on child and family characteristics. The associations between (a) emotional symptoms/mood and background variables, (b) emotional problems and conduct problems/hyperactivity and (c) mood and conduct problems/hyperactivity were examined with ordinal regression in univariate and multivariate models. Results: Of the background variables, child's sleeping problems had the most powerful association with emotional symptoms and mood. Abnormal emotional problems score and emotional symptoms were associated with abnormal conduct problems and hyperactivity scores. Of the emotional symptoms, low mood was the one associated most strongly with conduct problems and hyperactivity after controlling for all significant background variables and other emotional symptoms. Conclusions: We conclude that in young children sleep problems associate with low mood. Low mood associates with behavioural problems. When a child presents with low mood or behavioural problems, a comprehensive assessment of their psychiatric symptoms, as well as their sleep problems, is recommended.
  • Kristensen, Peter L.; Pedersen-Bjergaard, Ulrik; Due-Andersen, Rikke; Hoi-Hansen, Thomas; Grimmeshave, Lise; Lyssenko, Valeriya; Groop, Leif; Holst, Jens J.; Vaag, Allan A.; Thorsteinsson, Birger (BIOSCIENTIFICA LTD, 2016)
    Introduction: In healthy carriers of the T allele of the transcription factor 7-like 2 (TCF7L2), fasting plasma glucagon concentrations are lower compared with those with the C allele. We hypothesised that presence of the T allele is associated with a diminished glucagon response during hypoglycaemia and a higher frequency of severe hypoglycaemia (SH) in type 1 diabetes (T1DM). Material and methods: This is a post hoc study of an earlier prospective observational study of SH and four mechanistic studies of physiological responses to hypoglycaemia. 269 patients with T1DM were followed in a one-year observational study. A log-linear negative binomial model was applied with events of SH as dependent variable and TCF7L2 alleles as explanatory variable. In four experimental studies including 65 people, TCF7L2 genotyping was done and plasma glucagon concentration during experimental hypoglycaemia was determined. Results: Incidences of SH were TT 0.54, TC 0.98 and CC 1.01 episodes per patient-year with no significant difference between groups. During experimental hypoglycaemia, the TCF7L2 polymorphism did not influence glucagon secretion. Discussion: Patients with T1DM carrying the T allele of the TCF7L2 polymorphism do not exhibit diminished glucagon response during hypoglycaemia and are not at increased risk of severe hypoglycaemia compared with carriers of the C allele.
  • Lindberg, Nina; Oshukova, Svetlana; Miettunen, Jouko; Kaltiala-Heino, Riittakerttu (BioMed Central Ltd, 2016)
    Background: More research is needed to improve our understanding of the manifestation of psychopathic traits in violently offending girls. Our aim here was to assess psychopathic traits and psychopathy-related background variables in a Finnish nationwide consecutive sample of girls charged with violent crimes and referred to a pretrial forensic psychiatric examination. These girls were then compared to their male counterparts. Methods: The forensic psychiatric examination statements of 15-to 17-year-old juveniles who underwent a pretrial forensic psychiatric examination over a 31-year period (1980-2010) were reviewed. For each non-psychotic girl with a normal IQ (n = 25), an age-and offence type-matched male control was randomly selected. Offence and offender characteristics were collected from the forensic psychiatric examination reports, and a file-based assessment of psychopathic traits was performed using the Hare psychopathy checklist-youth version. Results: Approximately every third girl exhibited high traits of psychopathy, and no significant difference was observed between the genders. Focusing on the underlying factor and item scores, the girls scored significantly lower than boys on the Antisocial factor. Their interpersonal relationships were significantly more unstable and they significantly more often exhibited a history of child sexual abuse. During the index offence the girls were significantly less frequently intoxicated, and their victims were significantly more often family members or current or ex-intimates but significantly less often strangers. Conclusions: Although violently offending girls and boys do not differ on psychopathy total scores, significant gender differences exist on underlying factor and item scores as well as in background-and offence-related variables. Interventions should take into account these special features of violent girls.
  • Kilpinen, Lotta; Parmar, Amarjit; Greco, Dario; Korhonen, Matti; Lehenkari, Petri; Saavalainen, Paivi; Laitinen, Saara (Impact Journals LLC, 2016)
    Mesenchymal stromal cells (MSC) are currently used in many cell based therapies. Prior to use in therapy, extensive expansion is required. We used microarray profiling to investigate expansion induced miRNA and mRNA expression changes of bone marrow MSCs (BM-MSCs) derived from old and young donors. The expression levels of 36 miRNAs were altered in cells derived from the old and respectively 39 miRNAs were altered in cells derived from young donors. Of these, only 12 were differentially expressed in both young and old donor BM-MSCs, and their predicted target mRNAs, were mainly linked to cell proliferation and senescence. Further qPCR verification showed that the expression of miR-1915-3p, miR-1207, miR-3665, and miR-762 correlated with the expansion time at passage 8. Previously described BM-MSC-specific miRNA fingerprints were also detected but these remained unchanged during expansion. Interestingly, members of well-studied miR-17/92 cluster, involved in cell cycle regulation, aging and also development of immune system, were down regulated specifically in cells from old donors. The role of this cluster in MSC functionality is worth future studies since it links expansion, aging and immune system together.