Browsing by Subject "growth"

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  • Mäkelä, A.; Hari, P.; Kellomäki, Seppo (Suomen metsätieteellinen seura, 1981)
  • Attoui, Michel; Kangasluoma, Juha (2019)
    Tetraheptylammonium bromide (THABr), tetrabutylammonium bromide (TBABr) and tetraethylammonium bromide (TEABr) dissolved in methanol or water methanol mixtures (similar to 1 mM) produce via positive electrospray atomization and high resolution classification electrical classification standard clean ions (monomer and dier) which are singly charged. THABr is hydrophobic and insoluble in water, TBABr and TEABr are hygroscopic and water soluble (0.6 and 2.8 kg/L respectively). These ions are used to study the effect of hygroscopicity on the activation of aerosol particles in the sub 2 nm range via the detection efficiency measurement of a boosted ultrafine TSI condensation particle counter (3025A). Water solubility of particles seems to play a role in the activation and growth with butanol vapor in the CPC (condensation particle counter) independently of the size.
  • Makkonen, Olli (Suomen metsätieteellinen seura, 1967)
  • Väisänen, Eero; Kellomäki, Seppo; Hari, Pertti (Suomen metsätieteellinen seura, 1977)
  • Silventoinen, Karri; Pitkäniemi, Janne Mikael; Latvala, Antti; Kaprio, Jaakko; Yokoyama, Yoshie (2014)
    Length and weight in infancy are associated with neurodevelopment, but less is known about growth in other anthropometric measures. In this study we analyzed how the development in length, weight, head circumference, and chest circumference over infancy is associated with motor development in early childhood, using a twin study design. Information on physical development over infancy and the age at achievement of eight developmental milestones over early childhood was collected for 370 Japanese twin pairs. Linear mixed models were used to analyze how physical development is associated with motor development between individual twins, as well as within twin pairs, adjusting the results for shared maternal and postnatal environmental factors. Delayed motor development was associated with smaller body size over infancy, and we also found some suggestive evidence that it was associated with catch-up growth as well. When studying the associations within twin pairs discordant for motor development, similar associations were found. However, chest circumference showed the most robust association within discordant twin pairs. Smaller body size and rapid catch-up growth are associated with delayed motor development. When studying these associations within twin pairs and thus adjusting the results for gestational age as well as many other maternal and postnatal environmental factors, chest circumference showed the most robust association. Chest circumference, rarely used in developed countries, can offer additional information on prenatal conditions relevant for further motor development not achieved by more traditional anthropometric measures.
  • Kulha, Niko Aleksi; Pasanen, Leena; Holmström, Lasse; Grandpre, Louis de; Kuuluvainen, Timo Tapio; Aakala, Tuomas (2019)
    Identifying the scales of variation in forest structures and the underlying processes are fundamental for understanding forest dynamics. Here, we studied these scale-dependencies in forest structure in naturally dynamic boreal forests on two continents. We identified the spatial scales at which forest structures varied, and analyzed how the scales of variation and the underlying drivers differed among the regions and at particular scales. We studied three 2kmx2km landscapes in northeastern Finland and two in eastern Canada. We estimated canopy cover in contiguous 0.1-ha cells from aerial photographs and used scale-derivative analysis to identify characteristic scales of variation in the canopy cover data. We analyzed the patterns of variation at these scales using Bayesian scale space analysis. We identified structural variation at three spatial scales in each landscape. Among landscapes, the largest scale of variation showed the greatest variability (20.1-321.4ha), related to topography, soil variability, and long-term disturbance history. Superimposed on this large-scale variation, forest structure varied at similar scales (1.3-2.8ha) in all landscapes. This variation correlated with recent disturbances, soil variability, and topographic position. We also detected intense variation at the smallest scale analyzed (0.1ha, grain of our data), partly driven by recent disturbances. The distinct scales of variation indicated hierarchical structure in the landscapes studied. Except for the large-scale variation, these scales were remarkably similar among the landscapes. This suggests that boreal forests may display characteristic scales of variation that occur somewhat independent of the tree species characteristics or the disturbance regime.
  • Laakso, Kristina (Helsingin yliopisto, 2019)
    Clostridium botulinum is a Gram-positive, anaerobic, spore-forming bacterium that is found widely in nature. C. botulinum produces highly potent neurotoxin which causes paralysis. Yet, it is not known why the toxin is produced. C. botulinum poses a risk for the food industry, when spores germinate in food and start producing toxin. The aim of this study was to report how different carbohydrates and metabolites affect growth, toxin production and sporulation of C. botulinum. The hypothesis was that different substrates have different influence on the metabolism of C. botulinum. Earlier studies show which carbohydrates are utilized by C. botulinum but only few relate nutrient availability to toxin production. Glucose is the far most studied carbohydrate and it is known to support growth and toxin production. Growth in defined medium with added substrates was measured with Bioscreen. The method is based on measuring optical density of the cultures; optical density increases when the bacteria divide. Toxin levels were measured from 1 d and 5 d samples with a commercial ELISA (ELISA, enzyme-linked-immunosorbent-assay). The number of spores produced was measured after five days of growth. Vegetative cells were destroyed by heating (10 min, 80 °C) and MPN-method was conducted (MPN, most-probable number). With added glucose and glucose derivates (trehalose, maltotriose), growth and toxin production were induced most compared to control medium. High spore numbers were also measured. Higher concentrations of these substrates supported growth more than the lower concentrations. With higher concentrations of glucose and maltotriose the toxin levels were lower compared to low concentrations. With trehalose toxin levels were similar at high and low concentration. It can be concluded that the maximal growth density alone does not determine the toxin levels. N-acetylglucosamine (GlcNAc), which is found in bacterial cell walls, supported growth similar to glucose. GlcNAc supported also high sporulation and toxin production. Even though GlcNAc is a major component of chitin (e.g. the insect exoskeleton), chitin did not support toxin production or sporulation as efficiently as GlcNAc. The results indicate that C. botulinum might favor environments with fungi, dead bacteria or degraded chitin. By utilizing compounds from dead bacteria or insects, C. botulinum might have a role in circulating nutrients in anaerobic environment.
  • Pukkala, Timo; Kolström, Taneli (Suomen metsätieteellinen seura, 1987)
  • Hasygar, Kiran; Deniz, Onur; Liu, Ying; Gullmets, Josef; Hynynen, Riikka; Ruhanen, Hanna; Kokki, Krista; Kakela, Reijo; Hietakangas, Ville (2021)
    Energy storage and growth are coordinated in response to nutrient status of animals. How nutrient-regulated signaling pathways control these processes in vivo remains insufficiently understood. Here, we establish an atypical MAP kinase, ERK7, as an inhibitor of adiposity and growth in Drosophila. ERK7 mutant larvae display elevated triacylglycerol (TAG) stores and accelerated growth rate, while overexpressed ERK7 is sufficient to inhibit lipid storage and growth. ERK7 expression is elevated upon fasting and ERK7 mutant larvae display impaired survival during nutrient deprivation. ERK7 acts in the fat body, the insect counterpart of liver and adipose tissue, where it controls the subcellular localization of chromatin-binding protein PWP1, a growth-promoting downstream effector of mTOR. PWP1 maintains the expression of sugarbabe, encoding a lipogenic Gli-similar family transcription factor. Both PWP1 and Sugarbabe are necessary for the increased growth and adiposity phenotypes of ERK7 loss-of-function animals. In conclusion, ERK7 is an anti-anabolic kinase that inhibits lipid storage and growth while promoting survival on fasting conditions.
  • Greis, Ilppo; Kellomäki, Seppo (Suomen metsätieteellinen seura, 1981)
  • Dekoninck, Sophie; Hannezo, Edouard; Sifrim, Alejandro; Miroshnikova, Yekaterina A.; Aragona, Mariaceleste; Malfait, Milan; Gargouri, Souhir; de Neunheuser, Charlotte; Dubois, Christine; Voet, Thierry; Wickström, Sara A.; Simons, Benjamin D.; Blanpain, Cédric (2020)
    Summary During embryonic and postnatal development, organs and tissues grow steadily to achieve their final size at the end of puberty. However, little is known about the cellular dynamics that mediate postnatal growth. By combining in vivo clonal lineage tracing, proliferation kinetics, single-cell transcriptomics, and in vitro micro-pattern experiments, we resolved the cellular dynamics taking place during postnatal skin epidermis expansion. Our data revealed that harmonious growth is engineered by a single population of developmental progenitors presenting a fixed fate imbalance of self-renewing divisions with an ever-decreasing proliferation rate. Single-cell RNA sequencing revealed that epidermal developmental progenitors form a more uniform population compared with adult stem and progenitor cells. Finally, we found that the spatial pattern of cell division orientation is dictated locally by the underlying collagen fiber orientation. Our results uncover a simple design principle of organ growth where progenitors and differentiated cells expand in harmony with their surrounding tissues.
  • Teivaanmaki, T.; Cheung, Y. B.; Maleta, K.; Gandhi, M.; Ashorn, P. (2018)
    BackgroundDepressive conditions cause about 25 million disability adjusted life years in low-income countries annually. The incidence of depression rises after puberty, and the young age distribution in these countries may cause a high burden of adolescent depression. We aimed to assess the prevalence of reported depressive symptoms among rural adolescents in Malawi. Additionally, we assessed the association between birth weight, childhood growth, gender, and pubertal maturity and depressive symptoms. MethodsWe followed 767 children from the foetal period until 15-years-of-age. We used the Short Mood and Feelings Questionnaire (SMFQ) to examine reported depressive symptoms at 15years. The questionnaire was translated to local language and then back-translated until inaccuracies were not detected. Anthropometry was conducted at 1, 24, 120, and 180months of age. We performed regression models with imputed data to assess associations between the independent variables and depressive symptoms. As a sensitivity analysis, we ran the same regression models with participants with no missing data. ResultsA total of 523 participants were seen at 15years. The mean SMFQ score was 15 with 90% (95%CI 87-92%) of the participants scoring 11 points, the traditional cut-off for screening for depression. Birth weight, growth, gender, and pubertal maturity were not associated with the SMFQ score in the primary imputed analyses. In the sensitivity analysis, birth weight was associated with the SMFQ score in all models. ConclusionsThe prevalence of reported depressive symptoms was high among the studied population. It is uncertain how well the traditional cut-off of 11 points identifies children with clinically significant depressive symptoms in our sample. Our data do not support a hypothesis of an association between growth, gender, or pubertal maturity and depressive symptoms. Nevertheless, our results highlight the importance of the awareness of mental health problems in low-income countries.
  • Nylund, Markku; Nylund, Liisa; Kellomäki, Seppo; Haapanen, Antti (Suomen metsätieteellinen seura, 1979)
  • Seppälä, Kustaa (Suomen metsätieteellinen seura, 1972)
  • Rannikko, Heikki (Svenska handelshögskolan, 2012)
    Economics and Society – 240
    This study participates in several discussions on new technology-based firms, both from a population-level viewpoint and a firm-level viewpoint. The overall objective of this study is to examine how new technology-based firms grow. For the population level research this study provides new knowledge by analysing growth, and high growth, in the context of new technology-based firms. As a firm level phenomenon the present study provides new knowledge, both for the behavioural orientation literature and the resource dependence literature, by examining the possible causes and implications of entrepreneurial orientation and external resource mobilisation. The results of the descriptive empirical analysis picture the group of technology-based firms as a distinct sector of the economy. The emphasis on technology is shown through the finding that new technology-based firms’ managers value the distinction of technology over other business goals. Concerning growth patterns it is found that only a minority of new firms experience high annual growth, that growth is erratic and that it may take a long time for a new technology-based firm to achieve growth. The testing of the theoretical model suggests that entrepreneurial orientation is positively associated with growth performance and that the experienced growth performance is positively associated with entrepreneurial orientation. In conclusion, it seems that positive experiences in the past reinforce entrepreneurial orientation, which further strengthens the development of a firm. Concerning moderating factors it is found that technological distinctiveness modifies the relationship between entrepreneurial orientation and growth. The finding hints that entrepreneurship (risk-taking, boldness and pro-activeness) is more beneficial with strategies in which technological excellence and sophistication are not the top priority. In support of the resource dependence argument, it was found that financial resource mobilisation is positively associated with growth. The findings further give support for the view that embeddedness in a firm community of practice is associated with a higher level of resource mobilisation in a firm level. Concerning financial resource mobilisation, the results suggest that there is a positive association, both between identification with a community of practice and financial resource mobilization and between nature of co-operation in a community of practice and financial resource mobilisation. Towards operational resource mobilisation similar associations were not found. Overall, these results contribute to the innovation policy discussion by suggesting that hands-on innovation policy interventions may have firm-level effects, in addition to those of technological and business learning. The results suggest indirectly that supporting firms to create and maintain close ties with their exchange partners within a community of practice may lead to improved resource mobilisation e.g. through increased awareness of firm participants. This discovery contributes both to the research on innovation policy interventions and to the research on a more nuanced view of the resource dependence perspective.
  • Kellomäki, Seppo; Hari, Pertti (Suomen metsätieteellinen seura, 1980)
  • Kellomäki, Seppo; Hari, Pertti; Kanninen, Markku; Ilonen, Pirkko (Suomen metsätieteellinen seura, 1980)
  • Mäkelä, Annikki; Kellomäki, Seppo; Hari, Pertti (Suomen metsätieteellinen seura, 1980)