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

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

The long-term effects of in-work benefits in a life-cycle model for policy evaluation

This paper presents a life-cycle model of woman's labour supply, human capital formation and savings for the evaluation of welfare-to-work and tax policies. Women's decisions are formalised in a dynamic and uncertain environment. The model includes a detailed characterisation of the tax system and of the dynamics of family formation while explicitly considering the determinants of employment and education decisions: (i ) contemporaneous incentives to work, (ii ) future consequences for employment through human capital accumulation and (iii) anticipatory effects on the value of employment and education. The choice of parameters follows a careful calibration procedure, based of a large sample of data moments from the British population during the nineties using BHPS data. Many important features established in the empirical literature are reproduced in the simulation exercises, including the employment effects of the WFTC reform in the UK. The model is used to gain further insight into the responses to two recent policy changes, the October 1999 WFTC and the April 2003 WTC/CTC reforms. We find small but non-negligible anticipation effects on employment and education.

Tuning the metamagnetism of an antiferromagnetic metal

We describe a `disordered local moment' (DLM) first-principles electronic structure theory which demonstrates that tricritical metamagnetism can arise in an antiferromagnetic metal due to the dependence of local moment interactions on the magnetisation state. Itinerant electrons can therefore play a defining role in metamagnetism in the absence of large magnetic anisotropy. Our model is used to accurately predict the temperature dependence of the metamagnetic critical fields in CoMnSi-based alloys, explaining the sensitivity of metamagnetism to Mn-Mn separations and compositional variations found previously. We thus provide a finite-temperature framework for modelling and predicting new metamagnets of interest in applications such as magnetic cooling

Computing observables in curved multifield models of inflation — a guide (with code) to the transport method

We describe how to apply the transport method to compute inflationary observables in a broad range of multiple-field models. The method is efficient and encompasses scenarios with curved field-space metrics, violations of slow-roll conditions and turns of the trajectory in field space. It can be used for an arbitrary mass spectrum, including massive modes and models with quasi-single-field dynamics. In this note we focus on practical issues. It is accompanied by a Mathematica code which can be used to explore suitable models, or as a basis for further development

Seven lessons from manyfield inflation in random potentials

We study inflation in models with many interacting fields subject to randomly generated scalar potentials. We use methods from non-equilibrium random matrix theory to construct the potentials and an adaption of the ‘transport method’ to evolve the two-point correlators during inflation. This construction allows, for the first time, for an explicit study of models with up to 100 interacting fields supporting a period of ‘approximately saddle-point’ inflation. We determine the statistical predictions for observables by generating over 30,000 models with 2–100 fields supporting at least 60 efolds of inflation. These studies lead us to seven lessons: i) Manyfield inflation is not single-field inflation, ii) The larger the number of fields, the simpler and sharper the predictions, iii) Planck compatibility is not rare, but future experiments may rule out this class of models, iv) The smoother the potentials, the sharper the predictions, v) Hyperparameters can transition from stiff to sloppy, vi) Despite tachyons, isocurvature can decay, vii) Eigenvalue repulsion drives the predictions. We conclude that many of the ‘generic predictions’ of single-field inflation can be emergent features of complex inflation models

Efeito do treinamento intervalado de saltos verticais contínuos sobre a aptidão anaeróbia e variáveis determinantes do desempenho de endurance: um ensaio randomizado

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Desportos, Programa de Pós-Graduação em Educação Física, Florianópolis, 2015.No intuito de desenvolver um treinamento intervalado de sprints com um novo modo de exercício, a presente tese propôs a aplicação intermitente do teste de saltos verticais contínuos com 30s de duração (CJ30). O objetivo principal do estudo foi analisar o efeito desse treinamento (JIT), aplicado durante quatro semanas, sobre o desempenho do salto vertical com contramovimento (CMJ), a força explosiva, a aptidão anaeróbia, as variáveis determinantes do desempenho de endurance e as variáveis biomecânicas e fisiológicas da corrida em velocidade submáxima. O objetivo secundário foi verificar a relação da rigidez (vertical, KV e perna, KL) e coordenação intrassegmentos (CRP), medidas em velocidade submáxima, com a economia de corrida (EC). Vinte e dois (12 mulheres e 10 homens) corredores (as) recreacionais foram divididos randomicamente nos grupos experimental (GE) e controle (GC) por meio de sorteio. Todos os participantes realizaram treinamento contínuo em esteira, três vezes por semana, com intensidade de 70% do pico de velocidade (PV) identificado durante teste incremental. No treinamento do GE foram incluídas duas sessões do JIT por semana. Uma sessão do JIT foi composta de quatro a seis séries de CJ30 com cinco minutos de intervalo. Para análise estatística foi utilizada a ANOVA modelo misto com p = 0,05 e o Effect Size (ES). Na avaliação do CMJ houve efeito moderado do treinamento apenas no GE: 4,7% (ES = 0,99) para altura do salto vertical (H), 3,7% (ES = 0,82) para potência pico (PP) e 3,5% (ES = 0,83) para potência média (PM). A taxa de desenvolvimento de torque (TDT) do quadríceps aumentou 29,5% (ES = 1,02) no GE. Na avaliação do CJ30, considerando-se apenas os primeiros saltos (20%; ? 5 saltos), houve um aumento moderado no GE de 7,4% (ES = 0,87) para H e 5,6% (ES = 0,73) para PP; e moderado/alto de 11,7% (ES = 1,2) para a profundidade de agachamento (?Y). Considerando-se todos os saltos realizados no CJ30 também houve aumento de moderado a alto no GE de 10,1% (ES = 1,04) para H, 9,5% (ES = 1,1) para PP e 8,8% (ES = 1,1) para ?Y. Foi verificado aumento de moderado a alto no GE de 2,7% (ES = 1,11) para PV, 9,1% (ES = 1,28) para o VO2pico e 9,7% (ES = 1,23) para o limiar de lactato (vOBLA). No teste de EC a 9 km.h-1 verificou-se que a maioria das variáveis biomecânicas sofreram efeito do treinamento, tanto para o GE quanto para o GC, mas o consumo de oxigênio (VO2) e custo energético (CE) não sofreram efeito do treinamento. Destaca-se o aumento da rigidez vertical e da perna (8,1%), diminuição do tempo de voo (3,28%) e maior estado coordenativo do acoplamento coxa-perna (CRP; 3,4%). Verificou-se também correlação positiva do VO2 e CE como CRP coxa-perna (r ? 0,5). Por fim, pode-se concluir que a inclusão do JIT no treinamento de contínuo de endurance teve efeito significativo sobre o desempenho do CMJ (H), potência muscular (PP e PM), força explosiva (representada pela TDT), potência (H e PP dos primeiros saltos do CJ30) e capacidade (H e PP do CJ30) anaeróbia e potência (PV e VO2pico) e capacidade (vOBLA) aeróbia. Além disso, pode-se concluir que o estado coordenativo mais estável do acoplamento coxa-perna está ligado a menores valores de VO2 e CE e que KV e KL não têm relação significativa com a EC.Abstract : In order to develop a sprint interval training with a new exercise regimen, this thesis proposed the intermittent application of the continuous vertical jump test with 30s of duration (CJ30). The main objective of the study was to analyze the effect of this training (JIT), applied for four weeks, on countermovement jump (CMJ) performance, explosive strength, anaerobic fitness, determinants of endurance performance and biomechanical and physiological variables in submaximal running velocity. The secondary objective was to verify the relationship of the stiffness (vertical, KV and leg, KL) and intralimb coordination (CRP) measurements with the running economy (RE). Twenty-two (12 women and 10 men) recreational runners were randomized into experimental (EG) and control (CG) group by tossing a coin. All participants trained on a treadmill, three times a week, with an intensity of 70% of the peak treadmill velocity (PV) measured in a progressive maximal exercise test. In the EG training were included two sessions of JIT per week. The JIT session was composed of four to six CJ30 bouts with five-minute intervals. Statistical analysis was performed using ANOVA mixed model with p = 0.05 and the effect size (ES). In the CMJ evaluation, there was moderate training effect only in GE: 4.7% (SE = 0.99) for vertical jump height (H), 3.7% (ES = 0.82) for peak power (PP) and 3.5% (ES = 0.83) for mean power (MP). The rate of torque development (RTD) of the quadriceps increased 29.5% (ES = 1.02) on EG. In evaluating the CJ30, considering only the first jumps (20%; ? five jumps), there was a moderate increase in GE of 7.4% (ES = 0.87) for H and 5.6% (ES = 0.73) for PP; and moderate-high increase of 11.7% (ES = 1.2) for the squat depth (?Y). Considering all jumps performed in CJ30, there was an increase from moderate to high in EG of 10.1% (ES = 1.04) for H, 9.5% (ES = 1.1) for PP and 8.8 % (ES = 1.1) for ?Y. Moderate to high increase was observed in GE of 2.7% (ES = 1.11) for PV, 9.1% (ES = 1.28) for VO2peak and 9.7% (ES = 1.23) for the lactate threshold (vOBLA). In the RE test at 9 km.h-1 it was found training effect for the most of the biomechanical variables in both GE and GC, but no effect was found for the oxygen consumption (VO2) and energy cost (EC). It is highlighted the increase in vertical andleg stiffness (8.1%), decrease in flight time (3.28%) and a higher coordinative state of thigh-leg coupling (CRP; 3.4%). There was also positive correlation between VO2 and EC with the thigh-leg CRP (r ? 0.5). Finally, it can be concluded that the inclusion of the JIT in the continuous endurance training had a significant effect on CMJ performance (H), muscle power (PP and PM), explosive strength (RTD), anaerobic power (H and PP of the first 6s of CJ30) and capacity (H and PP of CJ30) and aerobic power (PV and VO2peak) and capacity (vOBLA). Moreover, it may be concluded that more stable coordinative state of thigh-leg coupling is associated to lower VO2 and EC values and that stiffness had no significant relationship with RE

Os Black Stars Chegam Ao Mercado: O Jogador Ganês Na Geopolítica Das Relações Internacionais Entre Inglaterra E Gana No Pós Colonialismo (1996-2014)

This Master's Thesis Aims To Analyze The Trajectory Of Ghanaian Athletes Inserted In English Football Between 1996 And 2014, Under The British Press Sighr. In This Way, It Is Sought To Reflect On The Neocolonial Discourse Through Sport, Especially In What Concerns The Constructions Of The Hierarchizations Of The Players From The Old African Colonies, In View Of The English Sport Context And The Geopolitical Perspective Of Contemporary England In Their Relations With The African Areas Of The Former Colonial Empire.Esta Dissertação De Mestrado Visa Analisar A Trajetória De Atletas Ganeses Inseridos No Futebol Inglês Entre 1996 E 2014, Sob O Olhar Da Imprensa Britânica. Procura-Se, Deste Modo, Refletir Sobre O Discurso Neocolonial Por Meio Do Esporte, Especialmente No Que Concerne As Construções Das Hierarquizações Dos Jogadores Provenientes Das Antigas Colônias Africanas, Tendo Em Vista O Contexto Esportivo Inglês E A Perspectiva Geopolítica Da Inglaterra Contemporânea Nas Suas Relações Com As Áreas Africanas Do Antigo Império Colonial.Dados abertos - Sucupira - Teses e dissertações (2018