Weinberg power counting and the quark determinant at small chemical potential

We construct an effective action for QCD by expanding the quark determinant in powers of the chemical potential at finite temperature in the case of massless quarks. To cut the infinite series we adopt the Weinberg power counting criteria. We compute the minimal effective action (~p^4), expanding in the external momentum, which implies the use of the hard thermal loop approximation. Our main result is a gauge invariant expression for the phase theta of the functional determinant in QCD, and recovers dimensional reduction in the high-temperature limit. We compute, analytically, in the range of p << 2 pi T, including perturbative and nonperturbative contributions, the latter treated within the mean field approximation. Implications for lattice simulations are briefly discussed.Comment: 5 pages, 2 figures. v2: title changed, expanded discussion and added example (calculation of at high temperature). Published in PR

Uniform semiclassical approximation in quantum statistical mechanics

We present a simple method to deal with caustics in the semiclassical approximation to the partition function of a one-dimensional quantum system. The procedure, which makes use of complex trajectories, is applied to the quartic double-well potential.Comment: 5 pages, 1 figure, Latex. Contribution to the Proceedings of the XXI Brazilian National Meeting on Particles and Fields (Sao Lourenco, October 23-27, 2000

Model-based design of experiments in the presence of structural model uncertainty: an extended information matrix approach

The identification of a parametric model, once a suitable model structure is proposed, requires the estimation of its non-measurable parameters. Model-based design of experiment (MBDoE) methods have been proposed in the literature for maximising the collection of information whenever there is a limited amount of resources available for conducting the experiments. Conventional MBDoE methods do not take into account the structural uncertainty on the model equations and this may lead to a substantial miscalculation of the information in the experimental design stage. In this work, an extended formulation of the Fisher information matrix is proposed as a metric of information accounting for model misspecification. The properties of the extended Fisher information matrix are presented and discussed with the support of two simulated case studies

Micobiota do solo de uma área de duna na restinga da Marambaia, Rio de Janeiro, RJ.

Este trabalho avaliou a micobiota do solo de uma duna nos terços inferior, médio e superior de encosta, localizada na Restinga da Marambaia, RJ. A área de estudo com aproximadamente 500 m2 está dividida em três terços, com a vegetação variando de arbustiva a arbórea. Foi delimitada uma gleba de dimensões de 50 x 50 m, onde foram abertas cinco minitrincheiras até a profundidade de 10 cm para coleta, sendo coletadas três amostras compostas formadas a partir da reunião de cinco amostras simples para análise do solo e caracterização da micobiota. A fertilidade do solo indicou que o terço inferior apresentou maiores teores de alumínio e menores de nutrientes. As unidades formadoras de colônias de fungos variaram de 4,6 x 103 a 9 x 104 ufc.g-1. Quarenta e nove fungos, num total de 85 isolados, pertencentes a 13 gêneros e 32 espécies foram identificados. Os gêneros mais frequentes foram Penicillium, Aspergillus e Trichoderma. A maior riqueza ocorreu no terço médio, porém uma espécie (Trichoderma pseudokoningi) foi comum entre as áreas. Este trabalho sugere que a Restinga da Marambaia apresenta grande diversidade fúngica

Effects from inhomogeneities in the chiral transition

We consider an approximation procedure to evaluate the finite-temperature one-loop fermionic density in the presence of a chiral background field which systematically incorporates effects from inhomogeneities in the chiral field through a derivative expansion. We apply the method to the case of a simple low-energy effective chiral model which is commonly used in the study of the chiral phase transition, the linear sigma-model coupled to quarks. The modifications in the effective potential and their consequences for the bubble nucleation process are discussed.Comment: 11 pages, 5 figures. v2: appendix and references added, published versio

The relationship between social capital and inflammatory biomarkers in early adulthood: A longitudinal study

Higher levels of social capital (SC) are associated with better health status. However, there is little evidence of the impact of SC on biological health outcomes in the early ages. To identify the association between SC in adolescence and inflammation levels in early adulthood. Prospective study using data from 2435 participants from the Epidemiological Health Investigation of Teenagers in Porto cohort. SC was assessed at age 17 through a self-administered questionnaire, and high-sensitivity C-reactive protein (hs-CRP) and leucocytes were measured in a fasting blood sample at 17 and 21 years-old. A principal components analysis was performed to identify the domains of SC. Simple linear regressions were performed to assess the association between SC components and inflammatory status at 17 and 21 years old. Pathway analysis was performed to assess the direct, indirect, and total effects of SC on hs-CRP and leucocyte levels. We did not find a significant total effect between SC at 17 years-old and hs-CRP at 21 years-old. However, the Trust/Reciprocity dimension showed a significant direct effect between SC and hs-CRP levels at 21 (β = −0.065, 95% CI: −0.129; −0.001), as well as a significant total effect (β = −0.075, 95% CI: −0.139; −0.011). Regarding leucocyte levels, total SC at 17 years-old was associated with leucocytes levels at 21 (β = −0.115, 95% CI: −0.205; −0.024). Significant direct (β = −0.104, 95% CI: −0.194; −0.014) and total effect (β = −0.107, 95% CI: −0.199; −0.015) of Trust/Reciprocity on leucocyte levels were observed. Adolescents with higher SC have a low inflammatory level in early adulthood, especially those with greater levels of trust/reciprocity. © 2024 The Authors. Stress and Health published by John Wiley & Sons Ltd.The authors like to thank the EPITeen (Epidemiological Health Investigation of Teenagers in Porto) team at the University of Porto (ISPUP), as well as all EPITeen participants who voluntarily shared their experiences and life paths with the team. This work was supported by Unidade de Investigação em Epidemiologia-Instituto de Saúde Pública da Universidade do Porto (EPIUnit) (UIDB/04750/2020) and Laboratório para a Investigação Integrativa e Translacional (ITR), Porto, Portugal (LA/P/0064/2020) and the Fundação para a Ciência e a Tecnologia Investigator contract CEECIND/01516/2017 (to SF)

The interaction between the renin-angiotensin system and peroxisome proliferator activated receptors: A hypothesis including the participation of mitochondria in aging

The objective of improving health is intimately associated with preventing and delaying age-related diseases. Nutritional and pharmacological approaches aimed at retarding aging are uncovering mechanisms, whose definitive roles in cell and tissue physiology need to be defined. In this article we hypothesize that peroxisome proliferator activated receptor (PPAR)-modulation is a pivotal process that underlies the association between mitochondria and the renin-angiotensin system (RAS) in aging. This hypothesis is based on several lines of evidence suggesting that: a) mitochondrial function and oxidant production are active participants in the aging process; b) PPARs, by regulating mitochondrial function and uncoupling proteins (UCP), seem to play a major role in the age-retarding effects of caloric restriction; c) RAS inhibition delays the deleterious effects of aging and also upregulates PPARs; and d) a number of physiological and molecular events that occur in experimental caloric restriction, and experimental and clinical RAS inhibition, involve changes in mitochondrial functions.Fil: de Cavanagh, E. M. V.. Universidad de Buenos Aires; ArgentinaFil: Piotrkowski, Barbara. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: Fraga, César Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; Argentin