Malgré le succès incontestable du Modèle Standard de la physique des particules, il est vraisemblable qu'il ne soit qu'une partie de la théorie complète de physique des particules -- comme c'est le cas des hypothèses de théories unifiées -- et ainsi de nombreux efforts ont été dédiés au développement de théorie de Nouvelle Physique. La Supersymmétrie est l'une des extensions les plus populaires puisque qu'elle permet non seulement de résoudre le problème de Naturalité mais présente aussi une candidat viable de matière sombre. Ce dernier point a été particulièrement mis en avant avec les récentes mesures expérimentales qui ont permis d'affiner significativement notre connaissance des propriétés de cette matière sombre. En particulier, la détermination de la densité relique de matière sombre dans l'univers est à présent réalisée avec une précision de l'ordre du pourcent. Dans le cadre du Modèle Standard Supersymmétrique Minimal (le MSSM), cette contrainte permet ainsi de tester la structure à une boucle de la théorie. Cependant c'est aussi un modèle présentant un très grand nombre de paramètres, comparé au Modèle Standard, et le calcul complet des observables à une boucle reste trop long pour être effectué sur l'ensemble de l'espace des paramètres. Dans cette thèse, je me suis ainsi intéressé à la possibilité de reproduire ces corrections à la boucle par un ensemble de couplages effectifs. L'approche effective présentant l'avantage de garder la simplicité d'un calcul effectué à l'arbre tout en conservant une trace des effets caractéristiques de boucles comme le non-découplage de certaines particules lourdes. Le LHC (Large Hadron Collider), dont les opérations ont démarrées juste après le début de ma thèse, soit à l'automne 2009, a fourni des données complémentaires aux observables de matière sombre. En effet le secteur du Higgs du MSSM est très peu flexible, ce qui a pour effet d'introduire ce que l'on appelle le problème du ``fine-tuning'', c'est à dire la nécessité d'avoir des valeurs très précises pour les paramètres. Afin d'y remédier, de nombreux modèles ont été créés au delà du MSSM, comme le NMSSM (en anglais Next-to-MSSM). Dans le but de suivre une approche plus générale, j'ai décidé au cours de cette thèse d'utiliser à nouveau l'approche effective, mais dans un but différent : alors que les couplages effectifs utilisés dans le cas de la matière sombre sont choisi pour reproduire le plus fidèlement possible les corrections à la boucle des particules du MSSM, les opérateurs effectifs que nous ajoutons au secteur du Higgs sont les effets à basse énergie (c'est à dire l'énergie de production du Higgs) d'une nouvelle physique à haute énergie. Bien que dédiées à deux buts différents, ces deux implémentations d'une même technique montrent bien ses différents atouts. Dans un des cas (celui du Higgs) les opérateurs effectifs permettent de paramétrer l'effet d'une physique ultraviolette inconnue, alors que dans l'autre cas cette physique ultraviolette se réduit au simple MSSM. / Despite the numerous successes of the Standard Model of particle physics, it is believed that the complete picture of particle physics could be larger, as a unified theory for instance, and thus many efforts have been devoted to the development of theories of new physics. Supersymmetry is one of the most popular extensions since in addition to a solution of the naturalness issue, it provides a viable dark matter candidate. This last sector being all the more important now that recent experimental measurements have significantly increased our knowledge about dark matter properties, in particular the experimental determination of the relic density has reached the accuracy of a few percent. When applied to the Minimal Supersymmetric Standard Model (the MSSM, which is the simplest supersymmetric extension of the Standard Model), this constraint will thus shed light on the one-loop structure of the model. The MSSM is however much more liberal with unconstrained parameters than the Standard Model is, and the full one-loop computation of the relic density tends to be too long to be carried out throughout this large parameter space. In this thesis I have thus explored the opportunity of accounting for those loop corrections through a set of effective couplings. This effective approach has the advantage of keeping the simplicity of a tree-level computation but encoding at the same time genuine loop features such as the non-decoupling of heavy particles. Complementary to those constraints are the observables related to the LHC, which started taking data shortly after the beginning of my PhD in fall 2009. The Higgs sector of the MSSM is tightly constrained and this results in a certain fine-tuning of the model, which led to the creation of many models beyond the MSSM (such as the Next-to-Minimal Supersymmetric Standard Model). Arguing for a more general approach, I have decided in this thesis to use again the effective approach but with a different aim : while the effective couplings in the case of dark matter are determined to account for the MSSM loop corrections, the effective operators we add to the Higgs sector of the MSSM are the remnants of the integration of a heavy extra spectrum. This effective approach, called the BMSSM (for Beyond the MSSM) is known to account for many different realisations of non-minimal supersymmetry, and we have used it as a framework to recast the results of the Higgs analyses carried out by ATLAS and CMS collaborations. This study has led to the caracterisation of the rich phenomenology of the Higgs sector in the BMSSM, with in particular the possibility for a signal quite different from Standard Model or MSSM expectations. Though based on distinct aims, the two implementations of the effective approach show the different advantages of an effective field theory. In the first case the effective operators are parametrising the effect of an unknown UV completion, whereas in the second we assume this UV completion to be the MSSM.

Submitted by Alexandre Pinho dos Santos Souza null (alexandre.pinho510@gmail.com) on 2016-10-20T18:04:06Z No. of bitstreams: 1 Thesis_Final_Cut.pdf: 1024756 bytes, checksum: 359153fd460f589a2a0359f05ca87b3d (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-10-26T18:50:11Z (GMT) No. of bitstreams: 1 souza_aps_dr_ilha.pdf: 1024756 bytes, checksum: 359153fd460f589a2a0359f05ca87b3d (MD5) / Made available in DSpace on 2016-10-26T18:50:11Z (GMT). No. of bitstreams: 1 souza_aps_dr_ilha.pdf: 1024756 bytes, checksum: 359153fd460f589a2a0359f05ca87b3d (MD5) Previous issue date: 2016-08-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Dentro da cosmologia, o modelo ΛCDM é considerado, pela comunidade científica, como aquele que melhor descreve o universo. Todavia, tal modelo sofre de alguns males que ainda precisam ser sanados. Entre eles se destacam o problema da constante cosmológica e o problema da coincidência cósmica. Atribui-se, neste modelo, a expansão acelerada do universo a um ente de origem desconhecida, chamado de energia escura. Parte da solução destes problemas está intimamente ligado em saber a natureza da energia escura. Por outro lado, devido a propriedades intrínsecas do espinor ELKO, faz-se possível atribuir ao mesmo o papel de energia escura. Deste modo, constrói-se aplicações cosmológicas do ELKO que possibilitem a resolução completa ou parcial dos problemas mencionados. Estas aplicações consistem basicamente na análise do sistemas de equações de Friedmann oriundas da anexação do Lagrangeano do ELKO na ação de Einstein-Hilbert. Dentro desse sistema se insere a mão o possível decaimento do ELKO em outros elementos que constituem o universo. Com este se alivia o problema da coincidência cósmica, enquanto que se confirma que o ELKO pode figurar como energia escura por meio dos resultados do sistema geral. Ao fim do trabalho se observa uma outra aplicação do ELKO, desta vez no cenário cosmológico de Einstein-Cartan. Neste se mostra que o modelo cosmológico que contém o ELKO como energia escura, e na presença de termo de torção, é análogo ao modelo cosmológico Λ(t). / In cosmology the ΛCDM model is the most accepted way to describe the universe. However, this model suffers some problems that have to be solved. Namely there are two of them which are attached in this thesis. They are the cosmic coincidence and the cosmological constant problem. Due this model it is possible to relate the universe’s accelerated expansion to dark energy. Part of solving these problems pass through knowing the origin of dark energy. It is known that the spinor ELKO has some fundamental properties that able scientists to connect them to dark universe elements, e.g. dark energy. So, some applications of ELKO in cosmology have been made in order to explore this possibility and to solve those fundamental problems. These application are based on analyzing ELKO in dynamical systems formed by Friedmann’s equations, where these equations comes from putting ELKO’s Lagranian in the Einstein-Hilbert action. In this system it is inserted a term of decaying. With such term it is possible to alleviate cosmic coincidence problem. On the other hand it is also possible to justify ELKO as dark energy as wished at the beginning. Last but not least, another application of ELKO in cosmology has been investigated. For such case is was shown that, with some considerations and approximations, ELKO in cosmology allied with Einstein-Cartan formalism can mimic Λ(t) cosmology results.

Orientador: Álvaro de Souza Dutra / Coorientador: Álvaro de Souza Dutra / Banca: Elias Leite Mendonça / Banca: Denis Dalmazi / Banca: Roldão da Rocha Júnior / Banca: José Abdala Helayë-Neto / Resumo: Dentro da cosmologia, o modelo ΛCDM é considerado, pela comunidade científica, como aquele que melhor descreve o universo. Todavia, tal modelo sofre de alguns males que ainda precisam ser sanados. Entre eles se destacam o problema da constante cosmológica e o problema da coincidência cósmica. Atribui-se, neste modelo, a expansão acelerada do universo a um ente de origem desconhecida, chamado de energia escura. Parte da solução destes problemas está intimamente ligado em saber a natureza da energia escura. Por outro lado, devido a propriedades intrínsecas do espinor ELKO, faz-se possível atribuir ao mesmo o papel de energia escura. Deste modo, constrói-se aplicações cosmológicas do ELKO que possibilitem a resolução completa ou parcial dos problemas mencionados. Estas aplicações consistem basicamente na análise do sistemas de equações de Friedmann oriundas da anexação do Lagrangeano do ELKO na ação de Einstein-Hilbert. Dentro desse sistema se insere a mão o possível decaimento do ELKO em outros elementos que constituem o universo. Com este se alivia o problema da coincidência cósmica, enquanto que se confirma que o ELKO pode figurar como energia escura por meio dos resultados do sistema geral. Ao fim do trabalho se observa uma outra aplicação do ELKO, desta vez no cenário cosmológico de Einstein-Cartan. Neste se mostra que o modelo cosmológico que contém o ELKO como energia escura, e na presença de termo de torção, é análogo ao modelo cosmológico Λ(t) / Abstract: In cosmology the ΛCDM model is the most accepted way to describe the universe. However, this model suffers some problems that have to be solved. Namely there are two of them which are attached in this thesis. They are the cosmic coincidence and the cosmological constant problem. Due this model it is possible to relate the universe's accelerated expansion to dark energy. Part of solving these problems pass through knowing the origin of dark energy. It is known that the spinor ELKO has some fundamental properties that able scientists to connect them to dark universe elements, e.g. dark energy. So, some applications of ELKO in cosmology have been made in order to explore this possibility and to solve those fundamental problems. These application are based on analyzing ELKO in dynamical systems formed by Friedmann's equations, where these equations comes from putting ELKO's Lagranian in the Einstein-Hilbert action. In this system it is inserted a term of decaying. With such term it is possible to alleviate cosmic coincidence problem. On the other hand it is also possible to justify ELKO as dark energy as wished at the beginning. Last but not least, another application of ELKO in cosmology has been investigated. For such case is was shown that, with some considerations and approximations, ELKO in cosmology allied with Einstein-Cartan formalism can mimic Λ(t) cosmology results / Doutor

Orientador: José Geraldo Pereira / Banca: Ruben Aldrovandi / Banca: Rogério Rosenfeld / Banca: Oliver Fabio Piatella / Banca: José Wadih Maluf / Resumo: Observações realizadas nas últimas três décadas confirmaram que o universo se encontra em um estado de expansão acelerada. Essa aceleração é atribuída à presença da chamada energia escura, cuja origem permanece desconhecida. A maneira mais simples de se modelar a energia escura consiste em introduzir uma constante cosmológica positiva nas equações de Einstein, cuja solução no vácuo é então dada pelo espaço de de Sitter. Isso, por sua vez, indica que a cinemática subjacente ao espaço-tempo deve ser aproximadamente governada pelo grupo de de Sitter SO(1,4), e não pelo grupo de Poincaré ISO(1,3). Nesta tese, adotamos tal argumento como base para a conjectura de que o grupo que governa a cinemática local é o grupo de de Sitter, com o desvio em relação ao grupo de Poincaré dependendo ponto-a-ponto do valor de um termo cosmológico variável. Com o propósito de desenvolver tal formalismo, estudamos a geometria de Cartan na qual o espaço modelo de Klein é, em cada ponto, um espaço de de Sitter com o conjunto de pseudo-raios definindo uma função não-constante do espaço-tempo. Encontramos que o tensor de torção nessa geometria adquire uma contribuição que não está presente no caso de uma constante cosmológica. Fazendo uso da teoria das realizações não-lineares, estendemos a classe de simetrias do grupo de Lorentz SO(1,3) para o grupo de de Sitter. Em seguida, verificamos que a estrutura da gravitação teleparalela--- uma teoria gravitacional equivalente à relatividade geral--- é uma geometria de Riemann-Cartan não linear. Inspirados nesse resultado, construímos uma generalização da gravitação teleparalela sobre uma geometria de de Sitter--Cartan com um termo cosmológico dado por uma função do espaço-tempo, a qual é consistente com uma cinemática localmente governada pelo grupo de de Sitter. A função cosmológica possui sua própria dinâmica e emerge na... / Abstract: Observations during the last three decades have confirmed that the universe momentarily expands at an accelerated rate, which is assumed to be driven by dark energy whose origin remains unknown. The minimal manner of modelling dark energy is to include a positive cosmological constant in Einstein's equations, whose solution in vacuum is de Sitter space. This indicates that the large-scale kinematics of spacetime is approximated by the de Sitter group SO(1,4) rather than the Poincaré group ISO(1,3). In this thesis we take this consideration to heart and conjecture that the group governing the local kinematics of physics is the de Sitter group, so that the amount to which it is a deformation of the Poincaré group depends pointwise on the value of a nonconstant cosmological function. With the objective of constructing such a framework we study the Cartan geometry in which the model Klein space is at each point a de Sitter space for which the combined set of pseudoradii forms a nonconstant function on spacetime. We find that the torsion receives a contribution that is not present for a cosmological constant. Invoking the theory of nonlinear realizations we extend the class of symmetries from the Lorentz group SO(1,3) to the enclosing de Sitter group. Subsequently, we find that the geometric structure of teleparallel gravity--- a description for the gravitational interaction physically equivalent to general relativity--- is a nonlinear Riemann--Cartan geometry.This finally inspires us to build on top of a de Sitter--Cartan geometry with a cosmological function a generalization of teleparallel gravity that is consistent with a kinematics locally regulated by the de Sitter group. The cosmological function is given its own dynamics and naturally emerges nonminimally coupled to the gravitational field in a manner akin to teleparallel dark energy models or scalar-tensor theories in general relativity. New in... / Doutor

Nesta tese, estudamos cosmologias com criação de matéria como alternativa ao modelo $\\Lambda$CDM. Generalizamos a equação de Boltzmann relativística com um termo de produção de partículas fenomenológico, de tal forma que a equação resultante seja capaz de reobter os resultados da termodinâmica de não-equilíbrio das equações de balanço e evolução de temperatura. Após obter o termo correto para a equação generalizada de Boltzmann, investigamos como o formalismo proposto altera a equação de evolução de relíquias cósmicas na presença de criação gravitacional de partículas. / In this thesis, we study matter creation cosmologies as an alternative to the $\\Lambda$CDM model. We generalize the relativistic Boltzmann equation with a phenomenological particle production term, in such a way that the resulting equation will be able to reproduce the non-equilibrium thermodynamics results of the balance equations and temperature evolution law. After obtaining the correct term to the generalized Boltzmann equation, we investigate how the proposed formalism changes the cosmic relic evolution equation in the presence of gravitational particle creation.

Culturas de células primárias diferem de acordo com as condições ambientais nas quais se encontra o doador. Recentemente demonstramos que o ciclo claro/escuro impõe um programa molecular hereditário em cultura celular. Com o intuito de investigar os mecanismos moleculares da memória celular, no presente trabalho isolamos células progenitoras CD133+ de explante de músculo cremaster e investigamos se a expressão de microRNAs (miRNAs), resulta em fenótipos diferentes de acordo com o ciclo claro/escuro. O sequenciamento global de miRNAs utilizando a plataforma SOLiD 4 e analisado pelos programas EdgeR, TargetScan e Metacore resultou na identificação de 541 miRNAs maduros, os quais apresentam dois perfis de expressão distintos de acordo com a hora de obtenção das culturas. miR-1249 e miR-129-2-3p são mais expressos em células obtidas durante o dia e favorecem a manutenção da pluri/multipotência celular. Já células obtidas à noite expressam maior conteúdo dos miR-182, miR-96-5p, miR-223-3p, miR-146a-3p e miR-146a-5p resultando na inibição da resposta inflamatória e no favorecimento da maturação celular quando comparadas às células obtidas de dia. A análise funcional da inibição da resposta inflamatória em células obtidas à noite foi confirmada por PCR array que revelou na menor expressão de genes relacionados à via de sinalização TLR/NF-κB, incluindo Traf6, um alvo do miR-146a. Além disso, a translocação nuclear de NF-κB é reduzida à noite e é inversamente proporcional ao nível de melatonina plasmática. Demonstramos ainda que a melatonina in vitro favorece o estado de pluripotência celular por aumentar a expressão de CD133, miR-1249 e miR-129-2-3p. No entanto, esse efeito depende do contexto celular visto que a expressão de receptores de melatonina também varia de acordo com a hora de obtenção da cultura. Em conjunto, nossos dados sugerem que o ciclo claro/escuro interfere no perfil de expressão de miRNAs e impõe uma variação no fenótipo de células progenitoras CD133+ / The phenotype of primary cells in culture varies according to the donor environmental condition. We have recently shown that the light/dark cycle impose a molecular program that is hereditable in culture. In order to evaluate the molecular mechanisms of cellular memory, here we isolated CD133+ progenitor cells from cremaster muscle explants and investigated whether the expression of microRNAs (miRNAs), could result in different phenotypes according the phase of ligh/dark cycle when cells were obtained. The global miRNA sequencing using SOLiD4 Platform, and analyzed by EdgeR, TargetScan and MetaCore, revealed the expression of a total of 541 mature miRNAs, and two distinct miRNAs signatures according to the hour when cells were obtained. miR-1249 and miR-129-2-3p are more expressed during daytime and favor the maintenance of cellular pluri/multipotency. Nighttime cells express higher amounts of miR-182, miR96-5p, miR-223-3p, miR-146a-3p and miR-146a-5p that inhibit the inflammatory response and favor the cellular maturation when compared to daytime cells. The functional analysis of the inflammatory response inhibition during nighttime was confirmed by PCR array and revealed lower expression level of genes related to TLR/NF-κB pathway, including Traf6, a putative target mRNA of miR-146a. Additionally, the nuclear translocation of NF-κB is reduced in nighttime cells and it is inversely correlated to the nocturnal the plasma level of melatonin. We also showed that melatonin in vitro favors the cellular pluri/multipotency, increasing CD133, miR-1249 and miR-129-2-3p expression. However, this effect depends on cellular context, as the expression of melatonin receptors also shows a daily variation. Altogether, our data suggest that the light/dark cycle interferes on miRNAs expression profile and imposes a rhythmic phenotype variation in CD133+ cells

Transparens på den finansiella marknaden finns för att marknadsaktörer ska ha möjlighet att se vilka finansiella instrument det handlas med, i vilken volym och till vilket pris. Transparensen bidrar till mer tillgänglig information och en effektivare marknad, där priset på instrumentet speglar dess faktiska värde. I den här uppsatsen behandlas EU-direktivet MiFID II och förordningen MiFIR. Syftet med MiFID II och MiFIR är att komplettera den tidigare transparensregleringen och dessutom verka för en enhetlig reglering på den europeiska finansiella marknaden. De flesta artiklarna angående transparens finns i MiFIR, vilka reglerar krav på transparens, men också undantag från transparens. Ett stort problem som finns på dagens finansiella marknad är att många transaktioner inte är föremål för transparens, utan görs i så kallade Dark Pools eller utanför handelsplatser. När handel sker i Dark Pools eller utanför en handelsplats är det svårt för marknadsaktörer att få tillgång till information om vilka och i vilken omfattning det handlas med instrumenten. Fördelen för de aktörer som handlar i Dark Pools och utanför en handelsplats är att de inte behöver exponera sina transaktioner och därmed inte heller dela med sig av eventuellt informationsövertag. Handel i Dark Pools och utanför handelsplatser är dessutom oftast billigare än handel på exempelvis börsen. Huvudsyftet med MiFID II och MiFIR är att, genom att begränsa handeln som sker i Dark Pools och utanför handelsplatser, öka transparensen på den finansiella marknaden. Trots detta visar lagstiftaren vikten av att väga andra intressen, som kan missgynnas av transparens, genom att införa flera olika undantag från transparenskraven. MiFID II och MiFIR träder i kraft först den 3 januari 2018, vilket gör det svårt att förutse regelverkets framtida följder. Det är först efter införandet av regelverket som vi kommer att se hur marknadsaktörerna reagerar på kraven och möjligheterna till undantagen. För att i uppsatsen kunna analysera en potentiell reaktion på den svenska finansiella marknaden, beaktas den svenska inställningen till tidigare transparensreglering. Vidare vägs fördelar med transparenskraven mot nackdelar och undantagens omfattning och utformning analyseras. Slutsatsen är att transparensreglerna kommer att öka transparensen på marknaden, i den mån att transparensen inte äventyrar den effektiva prisbildningen.

Personality neuroscience offers a new theory of the biological basis of personality traits. It involves the use of neuroscientific methodologies to study individual differences in behavior, motivation, emotion, and cognition. Personality psychology has contributed much in identifying the important dimensions of personality, but relatively little to understanding the biological sources of those dimensions. In recent years, personality psychology has become the foundation for the study of personality disorders, and by extension, neuroscience. First, I provide a theoretical foundation for the neuroscience of normal and abnormal personality traits. Second, I conduct two empirical studies on deviant personality traits captured by the Dark Triad (i.e., Machiavellianism, narcissism, and psychopathy) and relate them to universal human values. Study I shows that darker personalities endorse values that are self-enhancing, and that justify self-serving behavior. Study II investigates the relationship between the aforementioned constructs and empathy based on the idea that empathy is an important moderating factor of dark traits. In the discussion, suggestions for future studies in neuroscience are presented, as well as some limitations relating to the constructs.

We determine the mass scale of Planck galaxy clusters using gravitational lensing mass measurements from the Cluster Lensing And Supernova survey with Hubble (CLASH). We have compared the lensing masses to the Planck Sunyaev-Zeldovich (SZ) mass proxy for 21 clusters in common, employing a Bayesian analysis to simultaneously fit an idealized CLASH selection function and the distribution between the measured observables and true cluster mass. We used a tiered analysis strategy to explicitly demonstrate the importance of priors on weak lensing mass accuracy. In the case of an assumed constant bias, b(SZ), between true cluster mass, M-500, and the Planck mass proxy, M-PL, our analysis constrains 1 - b(SZ) = 0.73 +/- 0.10 when moderate priors on weak lensing accuracy are used, including a zero-mean Gaussian with standard deviation of 8% to account for possible bias in lensing mass estimations. Our analysis explicitly accounts for possible selection bias effects in this calibration sourced by the CLASH selection function. Our constraint on the cluster mass scale is consistent with recent results from the Weighing the Giants program and the Canadian Cluster Comparison Project. It is also consistent, at 1.34 sigma, with the value needed to reconcile the Planck SZ cluster counts with Planck's base Lambda CDM model fit to the primary cosmic microwave background anisotropies.

Abstract Mycorrhizal symbiosis is generally advantageous for plants in nutrient-poor soils. Arcto-alpine areas are relatively nutrient-poor, but abundantly inhabited by non-mycorrhizal species. Possibly, mycorrhizal symbiosis is not favoured due to the harsh climatic conditions and the short growing season, which constrain the photosynthetic gain and growth of the arcto-alpine plants. This hypothesis was theoretically evaluated by assuming that optimal mycorrhizal colonization maximizes the net carbon gain of the host plant. In addition, the prevalence of arbuscular mycorrhizal (AM) and dark-septate endophytic (DSE) fungi along an altitudinal gradient was studied in the field, and their effects on the plant performance were tested in the laboratory. In the model, the photosynthetic nutrient use efficiency (PNUE) had a key role in determining whether mycorrhizal strategy would be optimal for the plant net carbon gain. The model generated several colonization patterns depending on possible changes in PNUE and soil nutrient concentrations along altitudinal gradients. Field studies indicated that species-level colonizations do not yield a consistent pattern along the altitude except for fine endophyte, which increased along an altitudinal gradient. In a high-alpine field site root fungal colonizations were rare. Seasonal shifts in colonizations in low-alpine conditions were not found. DSE fungi were common root-associates in the field. In the laboratory, AM had a positive impact on the performance of Gnaphalium norvegicum at 15°C, but not at 8°C. DSE-inoculation did not colonize the roots, but it had a positive impact on seedling performance, which may be due to the saprophytic activity of the fungus in the substrate. Additionally, mycorrhizal inoculum was found to decrease the performance of a non-mycorrhizal plant in a competition experiment. Species-level mycorrhizal colonization patterns may differ from community-level pattern along altitudinal gradients and the relative abundance of different fungal symbionts may change along with the altitude. The performance of mycorrhizal plants in high-alpine conditions may be decreased due to several factors e.g. low temperature constraints on plant and fungal physiology and allocation, soil disturbances and low availability of inoculum. Climatic constraints for plant photosynthesis may thus affect the mycorrhizal colonization patterns in arcto-alpine conditions, but are not necessarily the primary cause for lower performance of mycorrhizal plants at higher altitudes.