On the possibility of braneworld quintessential inflation

We examine the possibility of achieving quintessential inflation, where the same field serves as both inflaton and quintessence, in the context of a five-dimensional braneworld. Braneworld cosmology provides an appropriate environment as it permits inflation with much steeper potentials than the conventional scenario, which is favourable to a late-time quintessence. We explore a wide space of models, together with contemporary observational data, to determine in which contexts such a picture is possible. We find that such a scenario, although attractive, is in fact impossible to achieve for the potentials studied due to the restrictiveness of current data.Comment: 11 pages RevTex file with 13 figure

Ultraviolet complete inflation: looking at inflation from fundamental physics

To completely describe the inflationary era in the early universe is an extremely ambitious task. The main reason is that its dynamics are highly sensitive to ultraviolet physics, making the knowledge of inflation dependent on our ignorance of what is happening at these energy scales. This is not necessarily a weakness of inflation as a paradigm; it is ultimately its most interesting characteristic. Accepting this lack of control on the details of inflationary dynamics brings observational cosmology and the search for an ultraviolet complete theory of gravity together. In this thesis, this duality is explored with the aim of making steps towards an efficient way of studying inflation and its predictions and signatures. This challenge is twofold; first, since fundamental theories are far from being able to explicitly determine the early universe physics, the construction of approximate toy models is unavoidable. For this reason, I identify the key issues for the building of a realistic inflation model, in particular the delicate flatness of the inflaton potential, the strong possibility of multifield dynamics and the necessity of a viable reheating, and in the light of these analyze how best to approximate an ultraviolet complete inflation. For this analysis, two different classes of case studies are presented: inflation in the brane picture and in a holography inspired scenario. On the other hand, since any toy model of an ultraviolet complete inflation necessarily presents a high level of complexity, the computation of predictions for observables is not trivial. For this purpose, I develop numerical tools that manage to compute these parameters efficiently and with a high level of accuracy for a broad range of inflation classes with more than one active field. For each case study, I determine the impact of the inclusion of microphysics contributions in the resulting observational signatures and confront them with data

Multifield consequences for D-brane inflation

We analyse the multifield behaviour in D-brane inflation when contributions from the bulk are taken into account. For this purpose, we study a large number of realisations of the potential; we find the nature of the inflationary trajectory to be very consistent despite the complex construction. Inflation is always canonical and occurs in the vicinity of an inflection point. Extending the transport method to non-slow-roll and to calculate the running, we obtain distributions for observables. The spectral index is typically blue and the running positive, putting the model under moderate pressure from WMAP7 constraints. The local f_NL and tensor-to-scalar ratio are typically unobservably small, though we find approximately 0.5% of realisations to give observably large local f_NL. Approximating the potential as sum-separable, we are able to give fully analytic explanations for the trends in observed behaviour. Finally we find the model suffers from the persistence of isocurvature perturbations, which can be expected to cause further evolution of adiabatic perturbations after inflation. We argue this is a typical problem for models of multifield inflation involving inflection points and renders models of this type technically unpredictive without a description of reheating

Assessment instruments used in acute stroke considering the International Classification of Functioning, Disability, and Health (ICF) as reference: a scoping review

The instruments that assess individuals with acute stroke are restricted to body function/structure and activity domains. Thus, understanding the measures used will enhance a rigorous assessment, monitoring neurological deficits. Analyzing the instruments used in the evaluation of acute stroke disability, considering the ICF as a reference. Review of the psychometric properties of the most used instruments. The methodology was carried out according to the recommendations of Joana Briggs Institute. We used the PubMed, Pedro and Web of Science databases in March 2022 and randomized controlled trials, non-randomized controlled trials, cohort study, case-control study, and cross-sectional analytic study. It was focused on the concept of assessment tools in an adult population with acute stroke. 94 of the 223 studies met the inclusion criteria. From these, 125 assessment measures were extracted, the most used measures were National Institute Health Stroke Scale, Barthel Index, Functional Independence Measure, Modified Rankin Scale, Mini-Mental State Examination and Fugl-Meyer Assessment. These tools were performance-based measures and were found to be valid and reliable. It was clarified that the assessment in acute stroke becomes pertinent, however most of the tools did not clarify the assessor. The most used measures were valid and reliable

Cosmology at the boundary of de Sitter using the dS/QFT correspondence

Using the dS/QFT correspondence in the context of inflation allows for the study of interesting, otherwise inaccessible physics. In particular, by studying inflation via its dual field theory at the boundary of the de Sitter space, it may be possible to study a regime of strongly coupled gravity at early times. The purpose of this work is to completely express cosmological observables in terms of the free parameters of a dual field theory and to compare them with CMB data. In this way, constraints on the observational parameters constrains the validity of the strongly coupled inflation picture by imposing limits on the parameters of the field theory. The fit with data defines a limit for the consistency and validity of the approach taken and shows that, within this limit, the model is almost unconstrained, but quite predictive, producing power spectra of density perturbations extremely near scale invariance

Chaotic inflation with kinetic alignment of axion fields

N-flation is a radiatively stable scenario for chaotic inflation in which the displacements of N≫1 axions with decay constants f1≤…≤fN<MP lead to a super-Planckian effective displacement equal to the Pythagorean sum fPy of the fi. We show that mixing in the axion kinetic term generically leads to the phenomenon of kinetic alignment, allowing for effective displacements as large as N−−√fN≥fPy, even if f1,…,fN−1 are arbitrarily small. At the level of kinematics, the necessary alignment occurs with very high probability, because of eigenvector delocalization. We present conditions under which inflation can take place along an aligned direction. Our construction sharply reduces the challenge of realizing N-flation in string theory

Transport equations for the inflationary spectral index

We present a simple and efficient method to compute the superhorizon evolution of the spectral index in multifield inflationary models, using transport equation techniques. We illustrate the evolution of n(s) with time for various interesting potentials

Haptoglobina e TNF-α, dois biomarcadores genéticos e circulantes associados às respostas de fase aguda na psoríase

Tese de mestrado. Biologia (Biologia Molecular e Genética). Universidade de Lisboa, Faculdade de Ciências, 2013A psoríase é uma doença que afecta cerca de 2% da população. É uma patologia imunitária e inflamatória que se manifesta através de placas eritmatosas. Nestas placas podemos encontrar infiltrados inflamatórios de células de diferentes tipos, como células dendríticas, macrófagos e células T. Pensa-se que o desencadear da psoríase possa estar relacionado com o TNF-α (Tumor Necrosis Factor α) e a haptoglobina, dois factores polimórficos envolvidos no processo de inflamação. O TNF-α é uma citocina proeminente nas reacções inflamatórias e a haptoglobina uma proteina de fase aguda tem um papel regulador nas mesmas. Assim sendo, este estudo visa a determinação dos polimorfismos destes dois genes, bem como a concentração extracelular da proteína do TNF-α entre duas populações, em uma população de doentes psoriásicos e em uma população de controlo. Através da análise dos resultados obtidos verificou-se que o genótipo GG para a posição -308 do promotor para o gene do TNF-α tem uma maior prevalência em doentes psoriásicos que em controlos. Para o polimorfismo da haptoglobina verificou-se também uma maior prevalência do genótipo Hp2-1 em doentes psoriásicos relativamente a indivíduos controlo. Ainda relativamente ao TNF-α verificou-se que a concentração sérica desta citocina é mais elevada para os doentes que para os controlos. Foi também verificado que uma maior concentração desta proteína está associada ao genótipo GG, comparativamente aos controlos. Resultado idêntico foi obtido para o genótipo Hp2-1 da haptoglobina. O PASI (Psoriasis Area Severity Index) foi também um dos parâmetros analisados, sendo que não se encontrou qualquer associação com os polimorfismos em estudo. No entanto foi possível verificar uma correlação inversa da concentração sérica de TNF-α com o valor do PASI. No futuro, seria proveitoso aumentar o número de indivíduos de ambas as populações e obter os dados clínicos dos pacientes.Psoriasis is a disease that affects 2% of the population. It is an immune and inflammatory pathology that manifests itself through erythematous plaques. In these plaques we can find inflammatory infiltrates of different cell types, like dendritic cells, macrophages and T cells. The aim of this work is to study TNF-α and haptoglobin, two important molecules in the inflammatory process, and that could be related with the onset or maintenance of the disease. TNF-α is a prominent cytokine and haptoglobin has a regulatory role in inflammatory reactions. TNF-α was analysed both at the gene and protein concentration level, whereas haptoglobin was only analysed at the gene level. The result analysis demonstrates that genotype GG for the -308 position in the promoter of the TNF-α (Tumor Necrosis Factor α) gene has a higher prevalence in psoriatic patients than controls, the same being found for the Hp2-1 haptoglobin genotype. The TNF-α concentration was observed to be increased in psoriatic patients, and also in the genotypes GG (TNF-α) and Hp2-1 (haptoglobin). Finally, it was found that the severity of the disease was not related to a specific genotype neither for TNF-α or haptoglobin genes. Although it was found that a relation exists between PASI (Psoriasis Area Severity Index) and the TNF-α concentration, a decrease in the TNF-α concentration appears to be associated with an increased severity of the disease. In the future, it would be better to increase the sample size for both control and patient groups and also to obtain the patient’s clinical data