27 research outputs found

    Identification and genetic inheritance of a new source of broad-spectrum extreme resistance to turnip mosaic virus (TuMV) in Brassica rapa

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    Brassica rapa line K185 was identified with broad-spectrum extreme resistance to turnip mosaic virus (TuMV). The resistance was effective against TuMV isolates UK 1, CZE 1, GBR 6, POL 1 and CDN 1 (representing major pathotypes 1, 3 and 4 and major resistance-breaking isolates) following mechanical inoculation. F1 plants from a cross between K185 and the rapid-cycling B. rapa ssp. trilocularis line R-o-18 (uniformly susceptible to all the above TuMV isolates), were resistant following challenge with TuMV isolates CDN 1 and GBR 6, indicating the involvement of dominant gene(s). F2 plants derived from a single F1, CDN 1- and GBR 6-resistant plant segregated for resistance to TuMV isolate GBR 6. The segregation ratio of resistant to susceptible plants was consistent with at least two loci controlling resistance and with both loci having dominant alleles for resistance. Other sources of broad-spectrum resistance to TuMV have been shown to involve the recessive allele retr01. The broad-spectrum resistance in K185 clearly involves different alleles to retr01 and provides the opportunity to introgress an alternative form of TuMV resistance into commercial B. rapa lines and thereby reduce the selection pressure for retr01 resistance breaking

    Genetic differentiation in an endangered and strongly philopatric, migrant shorebird

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    Background Populations living in fragmented habitats may suffer from loss of genetic variation and reduced between-patch dispersal, which are processes that can result in genetic differentiation. This occurs frequently in species with reduced mobility, whereas genetic differentiation is less common among mobile species such as migratory birds. The high dispersal capacity in the latter species usually allows for gene flow even in fragmented landscapes. However, strongly philopatric behaviour can reinforce relative isolation and the degree of genetic differentiation. The Southern Dunlin (Calidris alpina schinzii) is a philopatric, long-distance migratory shorebird and shows reduced dispersal between isolated breeding patches. The endangered population of the Southern Dunlin breeding at the Baltic Sea has suffered from habitat deterioration and fragmentation of coastal meadows. We sampled DNA across the entire population and used 12 polymorphic microsatellite loci to examine whether the environmental changes have resulted in genetic structuring and loss of variation. Results We found a pattern of isolation-by-distance across the whole Baltic population and genetic differentiation between local populations, even within the southern Baltic. Observed heterozygosity was lower than expected throughout the range and internal relatedness values were positive indicating inbreeding. Conclusions Our results provide long-term, empirical evidence for the theoretically expected links between habitat fragmentation, population subdivision, and gene flow. They also demonstrate a rare case of genetic differentiation between populations of a long-distance migratory species. The Baltic Southern Dunlin differs from many related shorebird species that show near panmixia, reflecting its philopatric life history and the reduced connectivity of its breeding patches. The results have important implications as they suggest that reduced connectivity of breeding habitats can threaten even long-distance migrants if they show strong philopatry during breeding. The Baltic Southern Dunlin warrants urgent conservation efforts that increase functional connectivity and gene flow between breeding areas.Peer reviewe

    Genetic differentiation in an endangered and strongly philopatric, migrant shorebird

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    Populations living in fragmented habitats may suffer from loss of genetic variation and reduced between-patch dispersal, which are processes that can result in genetic differentiation. This occurs frequently in species with reduced mobility, whereas genetic differentiation is less common among mobile species such as migratory birds. The high dispersal capacity in the latter species usually allows for gene flow even in fragmented landscapes. However, strongly philopatric behaviour can reinforce relative isolation and the degree of genetic differentiation. The Southern Dunlin (Calidris alpina schinzii) is a philopatric, long-distance migratory shorebird and shows reduced dispersal between isolated breeding patches. The endangered population of the Southern Dunlin breeding at the Baltic Sea has suffered from habitat deterioration and fragmentation of coastal meadows. We sampled DNA across the entire population and used 12 polymorphic microsatellite loci to examine whether the environmental changes have resulted in genetic structuring and loss of variation. </p

    Liikeasiakkaiden mobiililisäarvopalveluiden tarjonnan kilpailuympäristö

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    Tämä diplomityö esittelee ja analysoi kilpailuympäristöä tarjottaessa mobiililisäarvopalveluita yrityksille. Kilpailuympäristö käsitellään erillisenä osana koko liiketoimintaympäristöä. Ensimmäiseksi työ esittelee liiketoimintaan ja sen mahdollistavaan teknologiaan liittyvät peruskäsitteet. Käsitteet jotka erityisesti liittyvät kilpailuympäristöön käydään läpi, kuten myös itse liiketoimintaan liittyvät perustekijät, kuten liiketoimintamallit ja liikevaihdon lähteet. Teknologiaa esitellään lähinnä käsitteellisellä tasolla ja itse liiketoiminnan näkökulmasta: erillisiä tekniikoita ei kuvata yksityiskohtaisesti. Toiseksi työssä kuvataan itse mobiililisäarvopalvelut, sekä ulkoinen ympäristö, jossa yksittäinen palveluntarjoaja toimii. Palvelut on kategorisoitu, sekä niihin liittyvät liiketoiminnan kannalta tärkeät seikat on esitelty. Ulkoisen ympäristön osalta käsitellään mahdollisia pelureita, jotka saattavat lähteä palveluntarjontaan, sekä partnerointikuvioita ja itse asiakkaita. Tämän jälkeen on työn kaksi tärkeintä osaa: asiantuntijahaastattelut ja kilpailuanalyysi. Asiantuntijahaastatteluita käytettiin laajentamaan näkemystä ja saamaan viimeisimmät mielipiteet koskien kilpailullista liiketoimintaympäristöä. Kilpailuanalyysi on tehty käyttäen Michael E. Porterin kehittämää viiden voiman mallia

    Rejektijauhimen terien vaurioitumisen tutkiminen

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    Insinöörityö tehtiin UPM, Kajaanin tehtaalle. Työssä tutkittiin rejektijauhinta, joka sijaitsee tehtaan SC-hiomossa. SC-hiomossa valmistetaan massaa PK2:n tarpeisiin, joka valmistaa massasta aikakausilehtipaperia. Jauhimella jauhetaan rejektiä, jonka jauhatus parantaa paperin ominaisuuksia. Insinöörityön tarkoituksena oli selvittää, mistä rejektijauhimen terien väliin ajautunut irtometalli oli peräisin ja miten irtometallin joutuminen jauhinten terien väliin pystyttäisiin estämään tulevaisuudessa. Työssä analysoitiin terämateriaalin ja irtometallin koostumuksia ja tehtiin sen pohjalta parannusehdotuksia ongelman ratkaisemiseksi. Työ sisältää muutamia ratkaisuvaihtoehtoja ongelmaan ja antaa selkeän kuvan, siitä mitä asian korjaamiseksi tulee tehdä. Työssä selvisi, että irtometalli on todennäköisesti peräisin jauhimen roottoripuolen keskuslevyn siivekkeistä. Keskuslevyn siivekkeiden päihin suunniteltiin kartiomaiset reiät kavitaatioilmiön estämiseksi. Kavitaatioilmiötä aiheuttaa paineen vaihtelu.This Bachelor´s thesis was made for UPM, the Kajaani mill. The machine which was examined is a reject refiner and it is located in the SC groudwood plant. In addition, the thesis studied what could be done to prevent the foreign material from getting into the refiner. The first priority was to study how the foreign material had gone to the refiner. To find out the origin of the foreign material, the damaged refiner segments were sent to Rautaruukki Oyj in Raahe. The results revealed that the foreign material was made from the same material than the refiner segments. Most likely the foreign material was from the central plate wings. The thesis also studied the cavitation of the refiner´s segments. The problem of cavitation was solved by making holes into the central plate wings. The exhalation of the pressure relief causes cavitation

    Dynamics, genetic structure and viability of a small and declining Temminck's stint (<em>Calidris temminckii</em>) population

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    Abstract Globally, populations of several wader species are in decline. However, for most populations, information on abundance, its changes and the causes of declines is insufficient for designing successful management strategies to recover threatened populations. In this thesis I studied the status and population trends, nesting success, genetic structure and viability of a small, declining and threatened Temminck's stint population in the Bothnian Bay in the northern Baltic Sea. Historical population data, recent population counts in the early 1990s and in 1999–2002 and the demographic data showed that the decline is continuing, paralleled by declines in nesting success, recruitment and adult survival. Decline in nesting success was caused by a coincident increase in nest predation. Depredation was the main cause of nest losses. The common gull (Larus canus) and the ruddy turnstone (Arenaria interpres) were found to be the most important nest predators. I tested if an increase in nest concealment and consequent decrease in visibility lowers the efficiency of the early-departure antipredator behaviour of the species. An expected positive correlation emerged between visibility and flushing distance in the presence of alarm-giving birds, but not without them. This indicates that Temminck's stint exploits signals from other birds as early warning of an approaching predator. More nests were lost to predation on narrow than on wide shores. The nest predation rate was not related to habitat (natural vs. man-made) nor to differences in microhabitat characteristics associated with concealment. Overall variability of the mitochondrial control region was low in the one northeast Siberian and the three Fennoscandian populations studied. The occurrence of two maternal lineages in all Fennoscandian populations points to mixing of two previously isolated populations. The overall microsatellite genetic structuring (6 loci) in Fennoscandia was low. The pairwise comparison revealed a low but significant degree of differentiation between the Bothnian Bay and the two other Fennoscandian populations. However, no clear indication of genetic effects of small population size in the Bothnian Bay was detected. Matrix and Pradel-λ projection models, based on a ten year (1994–2003) capture-recapture data set, predicted a steep future decrease and a high risk of extinction within 50 years. Without immigration the decline would lead to extinction within 20 years. Population growth was the most sensitive to changes in adult survival, the rate of which declined during the study. Factors affecting adult survival most likely operate primarily during the non-breeding season in locations specific to the study population that are virtually unknown. Management efforts in the Bothnian Bay should, in addition to improving hatching success, first of all guarantee availability of wide, low-sward coastal breeding habitats for potential immigrants and recruits
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