229 research outputs found
Avian MHC: variation and selection in the wild
No full textIn vertebrates the Major Histocompatibility Complex (MHC) plays a central role in the specific immune defence against various pathogens. Compared with other coding genes the MHC genes exhibit an extremely high level of polymorphism that is maintained by balancing selection. The importance in the immune defence and the polymorphism make these genes interesting to study from an ecological and evolutionary perspective in populations subject to natural selection. In my thesis I have studied MHC in a population of wild songbirds, great reed warblers Acrocephalus arundinaceus. Firstly, I characterized parts of the MHC class I and II genes and I focused especially on transcribed genes since these are likely to be under selection. Then I developed a PCR-based screening method for investigating the MHC class I polymorphism in our study population. In the great reed warbler genome there was a large number of MHC class I and II genes and there was also evidence of balancing selection in these genes. There was a surprisingly high level of variation in the MHC genes in the great reed warblers within the study population considering the limited variation that have been detected using neutral markers. Secondly, I searched for evidence of selection on the MHC genes and for associations between life-history data and MHC genes. I found evidence that there is selection on the MHC class I alleles in great reed warblers. Avian malaria could be one such selective force since great reed warblers that had a large number of MHC alleles (heterozygous individuals) survived an infection with avian malaria (GRW2) more often than individuals with fewer MHC alleles. Hence, a large number of MHC alleles seem critical for survival. However, we did not find that MHC-compatibility is involved in female mate choice in the great reed warblers, as has been found in humans and mice, despite the fact that more MHC heterozygous great reed warbler siblings do survive more often. Finally, associations between certain MHC alleles, or a large number of MHC alleles, and resistance to specific diseases have so far been found in a handful of species. Most of these associations involve humans or are experiments that have been done under controlled conditions. To me it is compelling that the selection pressure from pathogens on MHC genes can be visualised also under natural conditions in wild populations, as e.g. the great reed warblers
Avian MHC: variation and selection in the wild
No full textPopular Abstract in Swedish Trastsångarnas MHC gener i klarspråk Inuti kroppen ser vi väldigt lika ut allihop; men om mina njurar skulle sluta att fungera är det inte alls säkert att just du kan donera en njure till mig. Detta beror på att våra transplantations-gener eller s.k. MHC- (Major Histocompatibility Complex) gener är olika, och vid en transplantation måste många av donatorns och mottagarens MHC-gener vara identiska. En gen är ett arvsanlag som finns i vår arvsmassa. Varje gen finns i två upplagor (en från mamma och en från pappa) och dessa kallas alleler (figur 1). Informationen i generna översätts och därför blir du t.e.x. lik din mamma, du har ju fått hälften av dina gener från henne. MHC-genernas uppgift är givetvis inte att tala om ifall vi kan donera njurar till varandra eller inte, utan det är en sidoeffekt av att de har en mycket viktig roll i vårt immunförsvar. MHC-generna finns hos alla ryggradsdjur och ser i stora drag lika ut hos alla arter. Det speciella med MHC-generna är att det finns extremt många olika alleler för de här generna. MHC-generna bildar MHC-molekyler som hjälper kroppens immunförsvar att känna igen vad som är kroppens egna celler och vad som är virus och bakterier. När MHC-molekylen hittar små protein-bitar som inte är kroppsegna aktiveras kroppens immunförsvar och oskadliggör viruset / bakterien. En MHC-molekyl kan hitta ett begränsat antal varianter av protein-bitar och därför är det ofta fördelaktigt att ha många olika MHC-molekyler i kroppen (se figur 1 i den engelska sammanfattningen). Jag har studerat MHC-generna i en liten brun sångfågel som heter trastsångare. Den häckar i vassområden i Mellansverige och övervintrar i Västafrika. Det speciella med trastsångarna, som vi studerar i sjön Kvismaren i Närke, är att deras häckningsekologi har följts under 20 års tid. Därför har vi en enorm kunskapsbank om trastsångarnas släktskap, öden och äventyr vid den här sjön. Trastsångarna visade sig ha många MHC-gener, minst åtta stycken, vilket kan jämföras med tamhöns (den fågelart där MHC-generna är mest välstuderade) som har två stycken. I mitt doktorandprojekt utvecklade jag en molekylärgenetisk metod för att kunna studera MHC-generna hos trastsångare. Jag ville ta reda på ifall trastsångare med många MHC-alleler, eller speciella MHC-alleler, överlevde bättre än andra. Dessutom undrade jag hur olika trastsångarnas MHC-alleler är. Den molekylära metoden som jag har använt för att studera MHC-generna fångar upp 2-12 MHC-alleler ifrån varje individ. Individer med få MHC-alleler (2 stycken) har mindre variation i sina MHC-gener jämfört med individer men många MHC-alleler (12 stycken). Hos trastsångarna i Kvismaren har nästan alla individer olika kombinationer av MHC-alleler, vi hittade 234 unika kombinationer av MHC-alleler i 248 individer. Ytterligare ett starkt bevis för att MHC-generna är variabla hos småfåglar fick jag när vi studerade MHC-variationen hos Seyshellsångaren, en liten släkting till trastsångaren där alla individer är nära besläktade med varandra. Det fanns naturligtvis total sätt färre MHC-alleler hos Seyshellsångaren jämfört med trastsångaren, men variationen mellan MHC-allelerna var lika stor hos båda arterna; d.v.s. en Seyshellsångare med två MHC-alleler bör kunna skydda sig lika bra mot olika sjukdomar som en trastsångare med två MHC-alleler. Jag nämnde tidigare att det kan vara fördelaktigt att ha många olika MHC-molekyler i kroppen eftersom det gör att man kan skydda sig mot fler sjukdomar. I en tidigare trastsångarstudie har man studerat hur par av trastsångarsyskon överlever sin första vinter och funnit att syskonet med störst variation i sina gener överlever oftare. När vi undersökte om den genetiska variationen i MHC-generna hade betydelse för överlevnad så pekade resultatet i samma riktning, d.v.s. syskonet med mest flest MHC-alleler överlevde oftare. Om man som mamma vill ge sina barn en stor genetisk variation i MHC-generna så ska man välja en pappa som har annorlunda MHC-alleler än vad man själv har. Man har faktiskt visat att precis så här kan det gå till hos människor och möss, mammor väljer att få barn med pappor som har annorlunda MHC-alleler än vad de själva har. Frekvensen av spontana aborter minskar om mamman och pappan har olika MHC-alleler och troligtvis används luktsinnet när mamman väljer ut sin partner. Jag undersökte om även trastsångarhonorna valde ut sina partners baserat på MHC-alleler, men det gjorde de inte. Trastsångarhonor tycker att välsjungande äldre hanar som är bosatta i vassruggar av hög status är mest attraktiva! Många sjukdomar i naturen kommer och går, vissa år är de vanliga och andra ovanliga. Olika arter av fågelmalaria, som drabbar trastsångare, varierar exempelvis över tiden. Många trastsångare blir smittade av fågelmalaria i Afrika och en stor andel dör där under sin första vinter. De häckande trastsångare som vi studerar i Kvismaren är de som har överlevt vintervistelsen i Afrika. Även vilka MHC-alleler som är vanliga varierar över tiden bland fåglarna i Kvismaren. Eftersom både vilka arter av fågelmalaria och vilka MHC-alleler som är vanligast varierade mellan år så undersökte vi om de samvarierade. Vi hittade ett samband mellan en speciell MHC-allel och en art av fågelmalaria och vi tolkade sambandet som att den speciella MHC-allelen var en ”överlevar-allel”. Vi fann dessutom ett samband mellan antalet MHC-alleler och ovannämnda art av fågelmalaria, d.v.s. det var större sannolikhet att man överlevde en infektion med fågelmalaria om man hade många MHC-alleler. Nyligen läste jag en översiktsartikel som handlade om 15 års studier av MHC i icke-modellorganismer (d.v.s. alla organismer utom mus och människa). Trots att MHC är svårt och komplext att studera så var slutklämmen i artikeln att MHC är det bästa systemet som finns tillgängligt för att studera samband mellan krafter i naturen (exempelvis sjukdomar) och gener. Man har funnit samband mellan sjukdomsresistens och MHC-gener hos människor, får, fiskar och kyckling; och med den här studien även hos trastsångare (fågelmalaria). Därmed finns det ett samband mellan MHC-gener och sjukdomsresistens rapporterat även från en vild fågel-population.In vertebrates the Major Histocompatibility Complex (MHC) plays a central role in the specific immune defence against various pathogens. Compared with other coding genes the MHC genes exhibit an extremely high level of polymorphism that is maintained by balancing selection. The importance in the immune defence and the polymorphism make these genes interesting to study from an ecological and evolutionary perspective in populations subject to natural selection. In my thesis I have studied MHC in a population of wild songbirds, great reed warblers Acrocephalus arundinaceus. Firstly, I characterized parts of the MHC class I and II genes and I focused especially on transcribed genes since these are likely to be under selection. Then I developed a PCR-based screening method for investigating the MHC class I polymorphism in our study population. In the great reed warbler genome there was a large number of MHC class I and II genes and there was also evidence of balancing selection in these genes. There was a surprisingly high level of variation in the MHC genes in the great reed warblers within the study population considering the limited variation that have been detected using neutral markers. Secondly, I searched for evidence of selection on the MHC genes and for associations between life-history data and MHC genes. I found evidence that there is selection on the MHC class I alleles in great reed warblers. Avian malaria could be one such selective force since great reed warblers that had a large number of MHC alleles (heterozygous individuals) survived an infection with avian malaria (GRW2) more often than individuals with fewer MHC alleles. Hence, a large number of MHC alleles seem critical for survival. However, we did not find that MHC-compatibility is involved in female mate choice in the great reed warblers, as has been found in humans and mice, despite the fact that more MHC heterozygous great reed warbler siblings do survive more often. Finally, associations between certain MHC alleles, or a large number of MHC alleles, and resistance to specific diseases have so far been found in a handful of species. Most of these associations involve humans or are experiments that have been done under controlled conditions. To me it is compelling that the selection pressure from pathogens on MHC genes can be visualised also under natural conditions in wild populations, as e.g. the great reed warblers
Passerine MHC: genetic variation and disease resistance in the wild
No full textThe passerine major histocompatibility complex (MHC) class I and IIB genes are different from those of the avian model species the chicken because passerines have (1) a larger number of MHC genes, (2) MHC genes with longer introns, and (3) MHC genes that are pseudo-genes. Most passerine MHC genes are transcribed (coding), extremely variable and subject to balancing selection. The high genetic diversity of the MHC genes of passerines is most likely maintained by selection from a large number of different pathogens. Association between MHC alleles and resistance to avian malaria infections have been reported in House Sparrows and Great Reed Warblers. Passerines are infected by a large number of different avian malaria infections. Therefore passerines and avian malaria is a study system that is well-suited to investigations of balancing selection and associations between MHC genes and disease resistance
Ecoimmunology perspective of host-parasite interactions in Limosa limosa across its migratory flyway
No full textTese de doutoramento em Biociências, na especialidade de Ecologia, apresentada ao Departamento de Ciências da Vida da Faculdade de Ciências e Tecnologia da Universidade de CoimbraFor long-distance migrant birds, ecological changes along the flyway and strenuous work, can unbalance immune investments and thereby increasing the vulnerability to disease and reducing survival. Despite an essential self-maintenance component, immunity comes with costs as well as benefits. At an ecological context (i.e. limited energy), trade-offs are generated between immunity and other competing physiological components, leading to variations on immune response across time (annual-cycle) and space (different environments). Moreover, immune responses also vary between species and are optimized according to specific situations of an individual´s life, to maximize survival and fitness.
Many ecoimmunology studies are focused on understanding the general patterns of immune responses in free-living birds, and what mechanisms mediate the changes in disease susceptibility, which in turn may affect population dynamics and survival. Information regarding these immunologic trade-offs remain largely unknown, and thus becoming of paramount importance when contextualized with climate change effects over migration ecology and the distribution of animal diseases.
The work comprised in this thesis addressed the general question of how differences in environmental pathogen pressure shape the innate and adaptive immunity of a free-living bird species. The long-distance migrant Black-tailed godwit (Limosa limosa; hereafter godwit), was used as a study model, since the two subspecies, nominate (Limosa limosa limosa) and Icelandic (L. l. islandica), vary on migratory strategy and habitat-use, which consequently differ in pathogen pressure. Below, I summarize the main contributions of my work for the ecoimmunology research area.
On chapter I, I tested whether the strength of immune response is indeed correlated with the environmental pathogen risk that differ with the migratory strategies and habitat use of godwit´s. The work focused innate baseline immunity parameters and I showed that it changes during the annual cycle of godwits in response to seasonal demands, availability of resources and physiological trade-offs. The investments in immune defence and the strategies deployed also varied in response to risk of getting infected. Trade-offs between innate immunity and other physiological components were more apparent during energetically demanding periods, such as the breeding season. For e.g. the Icelandic godwits downregulated innate responses when occupying parasite-poor breeding areas. Moreover, data indicates that immune adjustments and strategies are rather unique for each species. Nonetheless, migration seems to affect several bird species the same way, leading to an overall immunosuppression of the innate immune response and possibly to a higher vulnerability to disease.
On chapter II, the MHC-I gene of the Icelandic godwit is characterized based on Sanger and ultradeep Illumina MiSeq sequencing. Characterization mostly focused the α2 domain (exon 3) of this gene, which is known to be highly polymorphic and for coding the proteins that recognize pathogens. I found 47 new alleles of MHC-I exon 3 and of a putatively classical nature (functional). Individuals had between one to four loci, with at least three being expressed. The gene organization was quite similar to their closest relative, the Red knots (Calidris canutus), but comparing to other Charadriiformes species, the alleles had a lower polymorphism and few sites subjected to positive selection. This pattern most likely reflects the lower pathogenic pressure that individuals experience along their migratory flyway.
On chapter III, the role of pathogens as drivers of the diversifying selection of MHC genes is analysed. By using Illumina MiSeq sequencing we compared two godwit subspecies in terms of MHC-I exon 3 diversity and polymorphism. Both nominate and Icelandic godwits overlapped in terms of number of alleles (and loci) per individual, but nominate birds had significantly higher number of alleles and polymorphism. A population size effect could partly explain the differences seen between subspecies at the MHC-I diversity, but the number of positively selected sites for the nominate godwit was twice as high as those found for the Icelandic godwits. Positive selection differences suggest a stronger balancing selection for the nominate godwit and thus an adaptation to pathogen-rich habitats.
Chapter IV is focus on sexual signals and whether they truly advertise the quality of mates and their capacity to fight-off pathogens. I tested whether investment on innate immunity could be reflected by the sexual characters of godwits. Results indicate that some plumage features of male and female godwits were linked to soluble parameters of innate immunity and were not cost-free. Moreover, the signal was honest for males but not for females, a difference that may be related to sex-specific energetic demands and roles undertaken in breeding. Results suggest that females select males that are better at combining moult and migration and more able to fight infections.
Chapter V tackles a more pratical issue faced by researchers that work with free-living birds, and with no immediate access to laboratory facilities. Immunological assays have become a widespread tool for an integrate approach of immune variation, but it was unknown whether post-sampling repeated freeze-thawing (FT) cycles could affect the final outcome of the assays. An experimental approach testing post-sampling handling and methodological issues was implemented, and overall results showed that plasma (and serum) samples remain stable after repeated FT cycles, and thus the indices of immune function are mostly unaffected. Moreover, small methodological deviations of the assay´s protocols, caused no substantial variations on the final results.Para aves migradoras de longa distância, as mudanças ecológicas ao longo da migração, aliadas ao esforço físico, podem desequilibrar os investimentos em imunidade, levando a uma maior a vulnerabilidade à doença e reduzindo a capacidade de sobrevivência. Apesar de a imunidade ser um componente fisiológico de auto-preservação, esta implica custos bem como benefícios. Num contexto ecológico (ex. energia limitada), são gerados trade-offs entre a imunidade e outros componentes fisiológicos, dando origem a variações da resposta imune ao longo do tempo (ciclo anual) e do espaço (diferentes habitats). Para além disso, as respostas imunitárias também variam entre espécies e são optimizadas em função de situações específicas da vida de um indivíduo para maximizar a sobrevivência e o fitness.
Muitos estudos em ecoimunologia focam-se na compreensão dos padrões globais de respostas imunes em aves selvagens e nos mecanismos que alteram a susceptibilidade à doença, o que consequentemente poderá afectar a sobrevivência e a dinâmica populacional. Infelizmente a informação relativa a estes trade-offs imunológicos permanece maioritariamente desconhecida, tratando-se portanto de conhecimento essencial quando contextualizado com os efeitos das alterações climáticas sobre a ecologia das migrações e distribuição de doenças animais.
O trabalho englobado nesta tese procurou responder como é que as diferenças na pressão parasítica ambiental afectam a imunidade inata e adaptativa de aves selvagens. O migrador de longa distância Maçarico-de-bico-direito (Limosa limosa; Maçarico), foi usado como modelo de estudo, uma vez que duas das suas subespécies, nominal (Limosa limosa limosa) e islandesa (L. l. Islandica), variam na estratégia migratória e uso de habitat, que consequentemente difere na pressão parasítica. De seguida, resumo as principais contribuições do meu trabalho para a área da ecoimunologia.
No capítulo I, usando uma ave límicola como modelo, testei se a capacidade da resposta imune está de facto correlacionada com o risco de contrair doenças, uma vez que o risco difere com as estratégias de migração e habitat. O trabalho focou parâmetros de imunidade inata e demonstrei que esta não é de natureza estanque, mas que varia ao longo do ciclo anual dos Maçaricos em resposta à estação do ano, disponibilidade de recursos e trade-offs fisiológicos. Os investimentos na imunidade e estratégias aplicadas também variaram em resposta ao risco de infecção. Os trade-offs entre a imunidade e outros componentes fisiológicos, tornaram-se mais evidentes durante períodos energeticamente exigentes, como a reprodução. Por exemplo, neste período a subespécie islandesa suprimiu alguns componentes da imunidade inata, quando ocupava áreas onde o risco de infecção é baixo. Os resultados também indicam que os ajustes e estratégias imunitárias são únicas para cada espécie. Contudo a migração parece afectar as variadas espécies de aves da mesma maneira, dando origem a uma imunosupressão geral da resposta inata e possivelmente a uma maior vulnerabilidade à doença.
No capítulo II, o gene MHC-I da subespécie islandesa de Maçarico foi caracterizado com o auxílio da sequenciação de Sanger e Illumina MiSeq. A caracterização focou quase exclusivamente o domínio α2 (exão 3) deste gene, que é conhecido pelo seu polimorfismo e por codificar parte das glicoproteínas que reconhecem agentes patogénicos. Neste trabalho descobri 47 novos alelos do gene MHC-I, todos eles de natureza provavelmente clássica (ou funcional). Os Maçaricos islandeses têm entre um e quatro loci, com pelo menos três a ser expressos. A organização do gene MHC-I é bastante semelhante à do seu parente mais próximo, a Seixoeira (Calidris canutus), mas comparado com outras espécies de Charadriiformes, os alelos tinham um polimorfismo menor e poucos locais sujeitos a selecção positiva. Este padrão parece ser um reflexo de os indivíduos experienciarem a uma menor pressão patogénica ao longo da sua rota de migração.
No capítulo III, aprofundámos o papel da pressão patogénica como origem da diversificação dos genes MHC. Com o auxílio da sequenciação Illumina MiSeq, comparámos as duas subespécies de Maçarico relativamente à diversidade e ao polimorfismo do exão 3 do gene MHC-I. Ambas as subespécies sobrepuseram-se no que toca ao número de alelos (e loci) por indivíduo, mas a subespécie nominal, tinha significativamente mais alelos e tendencialmente um maior polimorfismo. Diferentes tamanhos populacionais poderão explicar parcialmente as diferenças encontradas entre subespécies ao nível da diversidade genética, no entanto, o número de locais sujeitos a selecção positiva encontrados para a subespécie nominal, foi duas vezes superior ao encontrado para a subespécie islandesa. As diferenças no que toca à selecção positiva, sugerem que a selecção natural é mais forte para a subespécie nominal e portanto uma adaptação a habitats ricos em parasitas.
O capítulo IV centra-se nos sinais sexuais e avalia se eles realmente reflectem a qualidade dos parceiros e a sua capacidade em combater doenças. Para isso testei se o investimento na imunidade inata poderia ser reflectido pelos carácteres sexuais secundários da plumagem dos Maçaricos. Os resultados indicam que algumas características da plumagem dos machos e fêmeas estão ligadas a componentes solúveis de imunidade inata e que os investimentos na plumagem são custosos. Para além disso, o sinal foi honesto para os machos, mas não para as fêmeas, uma diferença que poderá estar relacionada com constrangimentos energéticos específicos para cada sexo, e pelos papéis desempenhados durante a reprodução. Em resumo, os dados indicam que as fêmeas seleccionam não só os machos que são melhores a combinar a muda da plumagem e a migração, mas também os mais competentes no combate às infecções.
O Capítulo V aborda uma questão mais prática enfrentada por investigadores que trabalham com aves selvagens e sem acesso fácil ou imediato ao laboratório. Os ensaios imunológicos tornaram-se uma ferramenta generalizada para uma abordagem integrada da imunidade, mas desconhecia-se até à data se os ciclos repetidos de congelamento-descongelamento (CD) pós-amostragem poderiam afectar o resultado final dos ensaios imunológicos. Neste trabalho foi implementada uma abordagem experimental para o tratamento pós amostragem, bem como outras questões metodológicas, e os resultados indicaram que as amostras de plasma (ou soro) permanecem estáveis após ciclos repetidos de CD e que portanto, os componentes imunológicos permanecem inalterados. Mostrámos também que pequenas alterações metodológicas nos protocolos destes ensaios não causaram variações substanciais nos resultados finais.GHTM, IHMT, UNL – Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de LisboaThe Ruffords Foundatio
Explaining prevalence, diversity, and host specificity in a community of avian haemosporidian parasites
No full textData from manuscript "Explaining prevalence, diversity, and host specificity in a community of avian haemosporidian parasites" by Vincenzo A. Ellis, Xi Huang, Helena Westerdahl, Jane Jönsson, Dennis Hasselquist, Júlio M. Neto, Jan-Åke Nilsson, Johan Nilsson, Arne Hegemann, Olof Hellgren, Staffan BenschTHIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV
Perspektiv på fastigheter
No full textFastigheter upplevs inte som den hetaste av branscher. Trots det ibland svala intresset är fastighetsbranschen ändå en viktig faktor i samhället: vi ska alla ha någonstans att bo och stora värden finns placerade i tomter och byggnader. Det är också ett internationellt etablerat forskningsfält. Det finns alltså all anledning att branschen får den uppmärksamhet den förtjänar. Det är utgångspunkten för denna antologi skriven av forskare vid Enheten för fastighetsvetenskap vid Urbana studier. Fastighetsvetenskap är ett tvärvetenskapligt ämne: ekonomi, juridik, teknik, liksom beteende- och samhällsvetenskap finns representerade. I denna antologi vill vi lyfta fram ämnets bredd utifrån fyra teman. En marknad i förändring speglar såväl politiska som ekonomiska drivkrafter, medan Ökat fokus på miljö visar hur miljöaspekter blir alltmer centrala för fastighetsmarknadens utveckling. Temat Företagen fokuserar på företagen utifrån strategiska perspektiv såväl som genusperspektiv. Internationell utblick får avsluta som en påminnelse om att mycket av det som sker på den svenska marknaden är en del av en global ekonomi
Skärgårdskapell i Norden: En kortfattad översikt med några reflexioner
No full textArchipelago chapels of the North. A brief survey with some reflections By Christer Westerdahl
During the High and Late Middle Ages it seems that quite a number of maritime chapels were built and used in the archipelagoes of the North. The period is roughly the middle of the 14th to the middle of the 16th century, with varying factors of Lent enforcement and of the ensuing state of the international fish markets. These datings have, however, seldom been proved at the individual sites. Neither has a comparative perspective been used very often within this immense area. Most chapels are directly attached to harbours, presumably either for fishing or for shipping, some for both. The main emphasis is with some cases at the coasts of Agder, South Norway, but the scope is all- Nordic. Some of these harbours continue to be used during a long time. Their chapels may be used, reused, moved or rebuilt into Lutheran times. During the 17th and 18th centuries were built an even larger number of fishing chapels, especially on the Swedish northern side the Baltic, in the middle parts of the Bothnian Sea. These chapels have a background in long-range fishing by burghers of Gävle and other towns in the Baltic, north of Stockholm and towns situated at lake Mälaren west of Stockholm. The archipelagoes of Finland have a number of chapels which seem to have a combined background in seafaring and fishing. Some sites have been supposed to be intentionally connected to islands mentioned in the earliest Baltic sea itinerary sequence c. AD 1300. Within the borders of medieval Denmark there are few of this island type of chapel, mainly since the definition of a Scandinavian archipelago does not apply here. The whole area has got a number of separate burial sites for drowned sailors. Some of these probably had a chapel as well. The author tries to sketch types of indications of unknown chapel sites, such as place names, oral tradition as well as the position of these sites in a context of a non-Christian ritual landscape, with foundation myths associated with virgins and other female beings, of local and regional power and of service for fishermen and sailors, questions on the causes for the erection of chapels, problems in identification of remains and the probable dating in an all-Nordic perspective
Improving the reliability of genotyping of multigene families in non-model organisms
No full textA recommendation – based on reviews by Thomas Bigot, Helena Westerdahl and Sebastian Ernesto Ramos-Onsins – of the article: Gillingham, M. A. F., Montero, B. K., Wihelm, K., Grudzus, K., Sommer, S. and Santos P. S. C. (2020) A novel workflow to improve multi-locus genotyping of wildlife species: an experimental set-up with a known model system. bioRxiv 638288, ver. 3 peer-reviewed and recommended by Peer Community In Evolutionary Biology. doi: 10.1101/638288. doi: 10.1101/63828
Explaining prevalence, diversity, and host specificity in a community of avian haemosporidian parasites
No full textData from manuscript "Explaining prevalence, diversity, and host specificity in a community of avian haemosporidian parasites" by Vincenzo A. Ellis, Xi Huang, Helena Westerdahl, Jane Jönsson, Dennis Hasselquist, Júlio M. Neto, Jan-Åke Nilsson, Johan Nilsson, Arne Hegemann, Olof Hellgren, Staffan BenschTHIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV
Perspektiv på fastigheter
No full textFastigheter upplevs inte som den hetaste av branscher. Trots det ibland svala intresset är fastighetsbranschen ändå en viktig faktor i samhället: vi ska alla ha någonstans att bo och stora värden finns placerade i tomter och byggnader. Det är också ett internationellt etablerat forskningsfält. Det finns alltså all anledning att branschen får den uppmärksamhet den förtjänar. Det är utgångspunkten för denna antologi skriven av forskare vid Enheten för fastighetsvetenskap vid Urbana studier. Fastighetsvetenskap är ett tvärvetenskapligt ämne: ekonomi, juridik, teknik, liksom beteende- och samhällsvetenskap finns representerade. I denna antologi vill vi lyfta fram ämnets bredd utifrån fyra teman. En marknad i förändring speglar såväl politiska som ekonomiska drivkrafter, medan Ökat fokus på miljö visar hur miljöaspekter blir alltmer centrala för fastighetsmarknadens utveckling. Temat Företagen fokuserar på företagen utifrån strategiska perspektiv såväl som genusperspektiv. Internationell utblick får avsluta som en påminnelse om att mycket av det som sker på den svenska marknaden är en del av en global ekonomi
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