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Now showing items 828-847 of 2683
  • Mäntylä, Jorma Allan (Matemaattisten aineiden opettajien liitto MAOL ry, 2009)
    Tarkastelun kohteena on Galileo Galilein ja John Miltonin tapaaminen 1638 sekä Galilein inkvisitio-oikeudenkäynnin vaikutus John Miltonin käsitykseen sananvapaudesta. Artikkelia on täydennetty 2009.
  • Copenhagen, D.R.; Donner, K.; Reuter, T. (Blackwell, 1987)
    1. The performance of ganglion cells in detecting flashes of light near the absolute threshold was studied in an isolated eye-cup preparation of toad retina. Retinal ganglion cells, through which all visual information from the rods must flow to the brain, are in a key position for evaluating the still unproven hypothesis that the absolute light sensitivity is limited by rod noise (Barlow, 1956). 2. The dark-adapted threshold intensity for these cells, which were selected on the basis of their high sensitivity, averaged 0.029 Rh* flash-1 (range 0.008- 0.062), where Rh* signifies one photoisomerization per rod. On average, 46 photoisomerizations were needed per receptive field per flash to evoke a threshold response (range 16-84). 3. In the threshold region, frequency of responses versus mean flash intensity was determined. Threshold performance could be described by theoretical frequency of response curves, allowing intrinsic noise to be estimated in terms of an equivalent rate of photoisomerization-like (dark) events. In two completely characterized cells the rate of dark events corresponded to 0.03 and 0.06 Rh*DS-1, where Rh*D signifies one dark event per rod. 4. Threshold elevations produced by dim backgrounds were studied. The results of these experiments are consistent with a dark event rate equivalent to 0.046 Rh*DS-1, or 0.037 Rh*DS-1 after correcting for a probable decrease in summation time. 5. The rate of actual dark events (0.028 Rh*DS-1, 20 degrees C) measured in Bufo rods (Baylor, Lamb & Yau, 1980) is close to the equivalent rates determined here. Thus, for the ganglion cells signalling the dimmest lights, the dark events in rods appear to be the most significant intrinsic retinal noise source limiting detection.
  • Koivula, M.; Niemelä, J. (Blackwell, 2003)
    In order to study the ecological effects of logging combined with mechanical soil preparation, we sampled carabid beetles with pitfall trapping in nine spruce-dominated stands in central Finland in 1995–1998. Three of the stands were left intact as controls. Three 1600-m2 openings per stand were logged in the winter 1995–1996 into six stands. In three of these stands, light soil preparation was applied. Logging affected the species assemblages, but soil preparation per se had no clear effects. Open-habitat species increased in abundance in the openings one year after logging, but catches of generalist species in the different treatments did not differ from each other. A forest species, Calathus micropterus, was least abundant in the prepared openings. The amounts of logging residue, exposed mineral soil and aggregated humus, as well as the abundance of red wood ants, significantly explained variation in carabid assemblages.
  • Rizzo, A.F.; Korkeala, H.; Mononen, I. (American Society for Microbiology, 1987)
    Cellular fatty acids and monosaccharides in a group of 14 lactobacilli were analyzed by gas chromatography and the identity of the components was confirmed by gas chromatography-mass spectrometry. From the same bacterial sample, both monosaccharides and fatty acids were liberated by methanolysis, and in certain experiments, fatty acids alone were released by basic hydrolysis. The results indicate that basic hydrolysis gave more comprehensive information about the fatty acids, but the analysis of monosaccharides was found to be much more useful in distinguishing between different species of lactobacilli. The method described allowed differentiation of 11 of 14 Lactobacillus species, and even single colonies isolated from agar plates could be used for analysis without subculturing.
  • Ylä-Ajos, Maria; Tuominen, Satu; Hänninen, Laura; Ruusunen, Marita; Puolanne, Eero; Valros, Anna (TAYLOR & FRANCIS LTD., 2012)
    1. Investigations were made into the breast and leg muscle energy metabolism, and the quality of breast meat of turkeys after controlled atmosphere stunning or stun-killing (CAS) with various gas mixtures. In addition, the effect on meat quality of an increase in the chilling rate of turkey breast meat after hypercapnic or anoxic stun-killing was studied. 2. A total of 35 turkey toms within two replicate pens were individually stunned during consecutive weeks using one of 4 CAS methods. The stunning gases tested were high CO2 concentration (60% CO2 in air), high N2 concentration (98% N2, 2% O2), a mixture of 76% N2 and 24% CO2, and a biphasic method (first minute in mixture containing 40% CO2, 30% N2, and 30% O2; followed by two minutes in a mixture containing 60% CO2 in air). 3. The birds stunned with N2 displayed the highest initial reduction in muscle pH, but after 4 h post mortem there were no differences in pH values associated with the various CAS methods. 4. The CAS method alone had no statistically significant effect on the quality of turkey breast muscle when the chilling speed was rapid (0°C for 4 h, followed by storage at 4°C). When the chilling rate was slowed (20°C for4 h followed by storage at 4°C), a significant decrease in cooking loss and in Warner-Bratzler shear force was recorded for birds stun-killed with CO2. 5. This study shows that anoxic stun-killing with N2 had no adverse effects on meat quality despite the rapid post mortem pH decrease. The CAS with N2 allows rapid cooling of carcases without the risk of cold shortening, whereas with CO2-stun-killing of turkeys, the rate of chilling should be slower. Concerning meat quality, all the CAS methods tested were suitable for stunning turkeys.
  • Väliverronen, Esa (Viestinnän laitos, 2007)
    Tässä kirjassa tutkin sitä, millaisten tarinoiden, kuvien ja vertauskuvien kautta biotekniikasta ja geenitutkimuksen sovelluksista on kerrottu mediassa. Tärkeimpänä aineistoa ovat YLE:n ja MTV3: n geeniperimää ja biotekniikkaa käsittelevät tv-uutiset vuosilta 1985–2000. Nämä runsaat 200 uutisjuttuja antavat kiinnostavan läpileikkauksen aiheen käsittelystä ja muutoksista runsaan kymmenen vuoden aikana. Televisiouutisten lisäksi käytän aiheen taustoituksessa ja kahdessa tapausanalyysissa laajempaa media-aineistoa kuten sanoma- ja aikakauslehtiä ja tv-dokumentteja. Nämä tapaukset ovat paljon julkisuutta saaneet siirtogeeninen Huomen -lehmä sekä ihmisen geeniperimää kartoittanut Human Genome -projekti. Satunnaisemmin viittaan myös muutamiin elokuviin ja mainoksiin.
  • Enroth, Johannes (PUUTARHALIITTO., 2012)
  • Majumder, Mamun; Kumar, Ashwini; Heckman, Caroline; Kankainen, Matti; Pesonen, Sari; Jäger , Elke; Karbach , Julia; Joensuu, Timo; Kairemo, Kalevi; Partanen, Kaarina; Alanko, Tuomo; Hemminki, Akseli; Backman, Charlotta; Dienel, Kasper; von Euler, Mikael; Hakonen, Tiina; Juhila, Juuso; Ranki, Tuuli; Vassilev, Lotta; Vuolanto, Antti; Jaderberg, Magnus (BioMed Central Ltd, 2014)
  • Tiraboschi, Ettore; Guirado, Ramon; Greco, Dario; Auvinen, Petri; Fernando Maya-Vetencourt, Jose; Maffei, Lamberto; Castren, Eero (Hindawi Publishing Corporation, 2013)
  • Kiljunen, Saija; Pajunen, Maria I; Dilks, Kieran; Storf, Stefanie; Pohlschroder, Mechthild; Savilahti, Harri (BioMed Central Ltd, 2014)
    Abstract Background Archaea share fundamental properties with bacteria and eukaryotes. Yet, they also possess unique attributes, which largely remain poorly characterized. Haloferax volcanii is an aerobic, moderately halophilic archaeon that can be grown in defined media. It serves as an excellent archaeal model organism to study the molecular mechanisms of biological processes and cellular responses to changes in the environment. Studies on haloarchaea have been impeded by the lack of efficient genetic screens that would facilitate the identification of protein functions and respective metabolic pathways. Results Here, we devised an insertion mutagenesis strategy that combined Mu in vitro DNA transposition and homologous-recombination-based gene targeting in H. volcanii. We generated an insertion mutant library, in which the clones contained a single genomic insertion. From the library, we isolated pigmentation-defective and auxotrophic mutants, and the respective insertions pinpointed a number of genes previously known to be involved in carotenoid and amino acid biosynthesis pathways, thus validating the performance of the methodologies used. We also identified mutants that had a transposon insertion in a gene encoding a protein of unknown or putative function, demonstrating that novel roles for non-annotated genes could be assigned. Conclusions We have generated, for the first time, a random genomic insertion mutant library for a halophilic archaeon and used it for efficient gene discovery. The library will facilitate the identification of non-essential genes behind any specific biochemical pathway. It represents a significant step towards achieving a more complete understanding of the unique characteristics of halophilic archaea.
  • Shikano, Takahito; Laine, Veronika N.; Herczeg, Gabor; Vilkki, Johanna; Merilä, Juha (GENETICS SOC AM, 2013)
  • Csöndes, Izabella; Cseh, András; Taller, János; Poczai, Péter (SPRINGER NETHERLANDS, 2012)
  • Petersen, Jessica L.; Mickelson, James R.; Cothran, E. Gus; Andersson, Lisa S.; Axelsson, Jeanette; Bailey, Ernie; Bannasch, Danika; Binns, Matthew M.; Borges, Alexandre S.; Brama, Pieter; Machado, Artur da Camara; Distl, Ottmar; Felicetti, Michela; Fox-Clipsham, Laura; Graves, Kathryn T.; Guerin, Gerard; Haase, Bianca; Hasegawa, Telhisa; Hemmann, Karin; Hill, Emmeline W.; Leeb, Tosso; Lindgren, Gabriella; Lohi, Hannes; Lopes, Maria Susana; McGivney, Beatrice A.; Mikko, Sofia; Orr, Nicholas; Penedo, M. Cecilia T.; Piercy, Richard J.; Raekallio, Marja; Rieder, Stefan; Roed, Knut H.; Silvestrelli, Maurizio; Swinburne, June; Tozaki, Teruaki; Vaudin, Mark; Wade, Claire M.; McCue, Molly E. (Public Library of Science, 2013)
  • Narusyte, Jurgita; Ropponen, Annina; Silventoinen, Karri; Alexanderson, Kristina; Kaprio, Jaakko; Samuelsson, Asa; Svedberg, Pia (Public Library of Science, 2011)
  • Poczai, Peter; Matyas, Kinga Klara; Szabo, Istvan; Varga, Ildiko; Hyvönen, Jaakko; Cernak, Istvan; Gorji, Ahmad Mosapour; Decsi, Kincso; Taller, Janos (SPRINGER NEW YORK LLC, 2011)
  • Johnson, Nichola; Dudbridge, Frank; Orr, Nick; Gibson, Lorna; Jones, Michael E; Schoemaker, Minouk J; Folkerd, Elizabeth J; Haynes, Ben P; Hopper, John L; Southey, Melissa C; Dite, Gillian S; Apicella, Carmel; Schmidt, Marjanka K; Broeks, Annegien; Van’t Veer, Laura J; Atsma, Femke; Muir, Kenneth; Lophatananon, Artitaya; Fasching, Peter A; Beckmann, Matthias W; Ekici, Arif B; Renner, Stefan P; Sawyer, Elinor; Tomlinson, Ian; Kerin, Michael; Miller, Nicola; Burwinkel, Barbara; Marme, Frederik; Schneeweiss, Andreas; Sohn, Christof; Guénel, Pascal; Truong, Therese; Cordina, Emilie; Menegaux, Florence; Bojesen, Stig E; Nordestgaard, Børge G; Flyger, Henrik; Milne, Roger; Zamora, M P; Arias Perez, Jose I; Benitez, Javier; Bernstein, Leslie; Anton-Culver, Hoda; Ziogas, Argyrios; Clarke Dur, Christina; Brenner, Hermann; Müller, Heiko; Arndt, Volker; Dieffenbach, Aida K; Meindl, Alfons; Heil, Joerg; Bartram, Claus R; Schmutzler, Rita K; Brauch, Hiltrud; Justenhoven, Christina; Ko, Yon-Dschun; The GENICA (Gene Environment Interaction and Breast Cancer in Germany) Network; Nevanlinna, Heli; Muranen, Taru A; Aittomäki, Kristiina; Blomqvist, Carl; Matsuo, Keitaro; Dörk, Thilo; Bogdanova, Natalia V; Antonenkova, Natalia N; Lindblom, Annika; Mannermaa, Arto; Kataja, Vesa; Kosma, Veli-Matti; Hartikainen, Jaana M; Chenevix-Trench, Georgia; Beesley, Jonathan; kConFab Investigators; Australian Ovarian Cancer Study Group; Wu, Anna H; Van den Berg, David; Tseng, Chiu-Chen; Lambrechts, Diether; Smeets, Dominiek; Neven, Patrick; Wildiers, Hans; Chang-Claude, Jenny; Rudolph, Anja; Nickels, Stefan; Flesch-Janys, Dieter; Radice, Paolo; Peterlongo, Paolo; Bonanni, Bernardo; Pensotti, Valeria; Couch, Fergus J; Olson, Janet E; Wang, Xianshu; Fredericksen, Zachary; Pankratz, Vernon S; Giles, Graham G; Severi, Gianluca; Baglietto, Laura; Haiman, Chris; Simard, Jacques; Goldberg, Mark S; Labrèche, France; Dumont, Martine; Soucy, Penny; Teo, Soo; Yip, Cheng H; Phuah, Sze Y; Cornes, Belinda K; Kristensen, Vessela N; Grenaker Alnæs, Grethe; Børresen-Dale, Anne-Lise; Zheng, Wei; Winqvist, Robert; Pylkäs, Katri; Jukkola-Vuorinen, Arja; Grip, Mervi; Andrulis, Irene L; Knight, Julia A; Glendon, Gord; Mulligan, Anna M; Devillee, Peter; Figueroa, Jonine; Chanock, Stephen J; Lissowska, Jolanta; Sherman, Mark E; Hall, Per; Schoof, Nils; Hooning, Maartje; Hollestelle, Antoinette; Oldenburg, Rogier A; Tilanus-Linthorst, Madeleine; Liu, Jianjun; Cox, Angie; Brock, Ian W; Reed, Malcolm WR; Cross, Simon S; Blot, William; Signorello, Lisa B; Pharoah, Paul DP; Dunning, Alison M; Shah, Mitul; Kang, Daehee; Noh, Dong-Young; Park, Sue K; Choi, Ji-Yeob; Hartman, Mikael; Miao, Hui; Lim, Wei Y; Tang, Anthony; Hamann, Ute; Försti, Asta; Rüdiger, Thomas; Ulmer, Hans U; Jakubowska, Anna; Lubinski, Jan; Jaworska-Bieniek, Katarzyna; Durda, Katarzyna; Sangrajrang, Suleeporn; Gaborieau, Valerie; Brennan, Paul; McKay, James; Slager, Susan; Toland, Amanda E; Vachon, Celine; Yannoukakos, Drakoulis; Shen, Chen-Yang; Yu, Jyh-Cherng; Huang, Chiun-Sheng; Hou, Ming-Feng; González-Neira, Anna; Tessier, Daniel C; Vincent, Daniel; Bacot, Francois; Luccarini, Craig; Dennis, Joe; Michailidou, Kyriaki; Bolla, Manjeet K; Wang, Jean; Easton, Douglas F; García-Closas, Montserrat; Dowsett, Mitch; Ashworth, Alan; Swerdlow, Anthony J; Peto, Julian; dos Santos Silva, Isabel; Fletcher, Olivia (BioMed Central Ltd, 2014)
    Abstract Introduction We have previously shown that a tag single nucleotide polymorphism (rs10235235), which maps to the CYP3A locus (7q22.1), was associated with a reduction in premenopausal urinary estrone glucuronide levels and a modest reduction in risk of breast cancer in women age ≤50 years. Methods We further investigated the association of rs10235235 with breast cancer risk in a large case control study of 47,346 cases and 47,570 controls from 52 studies participating in the Breast Cancer Association Consortium. Genotyping of rs10235235 was conducted using a custom Illumina Infinium array. Stratified analyses were conducted to determine whether this association was modified by age at diagnosis, ethnicity, age at menarche or tumor characteristics. Results We confirmed the association of rs10235235 with breast cancer risk for women of European ancestry but found no evidence that this association differed with age at diagnosis. Heterozygote and homozygote odds ratios (ORs) were OR = 0.98 (95% CI 0.94, 1.01; P = 0.2) and OR = 0.80 (95% CI 0.69, 0.93; P = 0.004), respectively (P trend = 0.02). There was no evidence of effect modification by tumor characteristics. rs10235235 was, however, associated with age at menarche in controls (P trend = 0.005) but not cases (P trend = 0.97). Consequently the association between rs10235235 and breast cancer risk differed according to age at menarche (P het = 0.02); the rare allele of rs10235235 was associated with a reduction in breast cancer risk for women who had their menarche age ≥15 years (ORhet = 0.84, 95% CI 0.75, 0.94; ORhom = 0.81, 95% CI 0.51, 1.30; P trend = 0.002) but not for those who had their menarche age ≤11 years (ORhet = 1.06, 95% CI 0.95, 1.19, ORhom = 1.07, 95% CI 0.67, 1.72; P trend = 0.29). Conclusions To our knowledge rs10235235 is the first single nucleotide polymorphism to be associated with both breast cancer risk and age at menarche consistent with the well-documented association between later age at menarche and a reduction in breast cancer risk. These associations are likely mediated via an effect on circulating hormone levels.
  • Aivelo, Tuomas (2013)
    Genetiikan opetukseen kohdistuu laajaa huomiota, koska genetiikka on tieteenalana nopeasti muuttuva ja sen yhteiskunnalliset, kulttuuriset ja itsetuntemukseen liittyvät seuraamukset ovat yhä merkittävämpiä. Perinteistä Mendelin hernekokeisiin perustuvaa opetusta pidetään laajalti epäsopivana lähtökohtana opetukseen, vaikka se on maailmanlaajuisesti yleisin tapa opettaa genetiikkaa. Myös Suomessa perinteinen mendelistinen genetiikka on sekä oppikirjoissa että opetussuunnitelmissa tyypillisin tapa opettaa geenien toimintaa ja ominaisuuksien periytyvyyttä. Mendelististä lähestymistapaa on syytetty muun muassa geneettisen determinismin ja vanhanaikaisen geenimallin opettamisesta. Kritiikin mukaan opetus keskittyy epärealistiin perinnöllisyystehtäviin ja itse geenien toimintaa ja ilmiasun syntymistä käsitellään vähemmän. Lähdin tutkimaan suomalaisen genetiikan opetuksen tilannetta ja lukiolaisten oppimista selvittääkseni onko kritiikki perusteltua. Tutkin opiskelijoiden käsityksiä geenien toiminnasta osana biologian kansalliskilpailua tammikuussa 2013. Neljään monivalintakysymykseen vastasi 632 lukiolaista 73 lukiosta ja tutkin vastaukset kvantitatiivisella analyysillä. Samassa yhteydessä selvitin kilpailuun osallistuneiden opiskelijoiden opettajilta lukiossa käytössä olevaa kirjasarjan. Tutkin kaikkien käytettyjen kirjasarjojen lukion kakkoskurssin kirjan aineistolähtöisellä kvalitatiivisella analyysillä ja etsin sieltä kaikki esitellyt geenimallit. Luokittelin historialliset geenimallit Niklas Gericken luokittelun mukaan ja tutkin mallien sisäistä hybridisaatiota. Lisäksi etsin kirjoista geenin, dominanssin ja resessiivisyyden määritelmät, sekä kaikki väitteet ympäristön vaikutuksesta ilmiasuun. Opiskelijoilta paljastui useita virhekäsityksiä: he eivät osanneet tehdä eroa perimän ja ilmiasun välillä ja käsitys geenien toiminnasta oli puutteellinen. Erityisen korostunut oli näkemys, että perimä ja ympäristö aiheuttavat kumpikin oman osansa ilmiasusta, mutta nämä eivät vuorovaikuta keskenään. Tilanne oli kuitenkin parempi kuin oppikirjoja tutkiessa voisi odottaa. Oppikirjoissa esiteltiin useita erilaisia historiallisia malleja geenien toiminnasta, mutta modernia, nykytietämyksen mukaista mallia ei esitelty lainkaan. Geenimalleista ei puhuttu eksplisiittisesti mallina, eikä eri geenin määritelmiä selvennetty. Ympäristön vaikutus ilmiasuun tuotiin erittäin harvoin oppikirjoissa esille. Tein lisäksi ehdotuksia oppimateriaalien, opetussuunnitelmien ja opetuksen sisältöön ja kuvailen mahdollisia tulevia tutkimusaiheita.
  • Voigt, H.-R. (Västnyländska Kultursamfundet, 1997)