On Migdal's theorem and the pseudogap

We study a model of quasiparticles on a two-dimensional square lattice coupled to Gaussian distributed dynamical molecular fields. The model describes quasiparticles coupled to spin or charge fluctuations, and is solved by a Monte Carlo sampling of the molecular field distributions. When the molecular field correlations are sufficiently weak, the corrections to the self-consistent Eliashberg theory do not bring about qualitative changes in the quasiparticle spectrum. But for a range of model parameters near the magnetic boundary, we find that Migdal's theorem does not apply and the quasiparticle spectrum is qualitatively different from its mean-field approximation, in that a pseudogap opens in the quasiparticle spectrum. An important feature of the magnetic pseudogap found in the present calculations is that it is strongly anisotropic. It vanishes anlong the diagonal of the Brillouin zone and is large near the zone boundary. In the case of ferromagnetic fluctuations, we also find a range of model parameters with qualitative changes in the quasiparticle spectral function not captured by the one-loop approximation, in that the quasiparticle peak splits into two. We provide intuitive arguments to explain the physical origin of the breakdown of Midgal's theoremComment: revised versio

Different circulating biomarkers in women and men with paroxysmal atrial fibrillation: results from the AF-RISK and RACE V studies

Aims The clinical risk profile of atrial fibrillation (AF) patients is different in men and women. Our aim was to identify sex differences in blood biomarkers in patients with paroxysmal AF. Methods and results Sex differences in 92 blood biomarkers were measured in 364 patients included in our discovery cohort, the identification of a risk profile to guide atrial fibrillation therapy (AF-RISK) study, assessed by multivariable logistic regression and enrichment pathway analysis. Findings were subsequently confirmed in 213 patients included in our validation cohort, the Reappraisal of Atrial Fibrillation: Interaction between HyperCoagulability, Electrical remodelling, and Vascular Destabilisation in the Progression of AF (RACE V) study. In the discovery cohort, mean age was 59 +/- 12 years, 41% were women. CHA(2)DS(2)-VASc-score was 1.6 +/- 1.4. A total of 46% had hypertension, 10% diabetes, and 50% had heart failure, predominantly with preserved ejection fraction (47%). In women, activated leucocyte cell adhesion molecule (ALCAM) and fatty acid binding protein-4 (FABP-4) were higher. In men, matrix metalloproteinase-3 (MMP-3), C-C motif chemokine-16 (CCL-16), and myoglobin were higher. In the validation cohort, four out of five biomarkers could be confirmed: levels of ALCAM (P = 1.73 x 10(-4)) and FABP-4 (P = 2.46 x 10(-7)) and adhesion biological pathways [false discovery rate (FDR) = 1.23 x 10(-8)] were higher in women. In men, levels of MMP-3 (P = 4.31 x 10(-8)) and myoglobin (P = 2.10 x 10(-4)) and markers for extracellular matrix degradation biological pathways (FDR = 3.59 x 10(-9)) were higher. Conclusion In women with paroxysmal AF, inflammatory biomarkers were more often higher, while in men with paroxysmal AF, biomarkers for vascular remodelling were higher. Our data support the clinical notion that pathophysiological mechanisms in women and men with AF may differ

Different circulating biomarkers in women and men with paroxysmal atrial fibrillation: results from the AF-RISK and RACE V studies

Aims The clinical risk profile of atrial fibrillation (AF) patients is different in men and women. Our aim was to identify sex differences in blood biomarkers in patients with paroxysmal AF. Methods and results Sex differences in 92 blood biomarkers were measured in 364 patients included in our discovery cohort, the identification of a risk profile to guide atrial fibrillation therapy (AF-RISK) study, assessed by multivariable logistic regression and enrichment pathway analysis. Findings were subsequently confirmed in 213 patients included in our validation cohort, the Reappraisal of Atrial Fibrillation: Interaction between HyperCoagulability, Electrical remodelling, and Vascular Destabilisation in the Progression of AF (RACE V) study. In the discovery cohort, mean age was 59 +/- 12 years, 41% were women. CHA(2)DS(2)-VASc-score was 1.6 +/- 1.4. A total of 46% had hypertension, 10% diabetes, and 50% had heart failure, predominantly with preserved ejection fraction (47%). In women, activated leucocyte cell adhesion molecule (ALCAM) and fatty acid binding protein-4 (FABP-4) were higher. In men, matrix metalloproteinase-3 (MMP-3), C-C motif chemokine-16 (CCL-16), and myoglobin were higher. In the validation cohort, four out of five biomarkers could be confirmed: levels of ALCAM (P = 1.73 x 10(-4)) and FABP-4 (P = 2.46 x 10(-7)) and adhesion biological pathways [false discovery rate (FDR) = 1.23 x 10(-8)] were higher in women. In men, levels of MMP-3 (P = 4.31 x 10(-8)) and myoglobin (P = 2.10 x 10(-4)) and markers for extracellular matrix degradation biological pathways (FDR = 3.59 x 10(-9)) were higher. Conclusion In women with paroxysmal AF, inflammatory biomarkers were more often higher, while in men with paroxysmal AF, biomarkers for vascular remodelling were higher. Our data support the clinical notion that pathophysiological mechanisms in women and men with AF may differ.Nephrolog

Time of onset of atrial fibrillation and atrial fibrillation progression data from the RACE V study

Aims Atrial fibrillation (AF) progression is associated with adverse outcome, but the role of the circadian or diurnal pattern of AF onset remains unclear. We aim to assess the association between the time of onset of AF episodes with the clinical phenotype and AF progression in patients with self-terminating AF. Methods and results The Reappraisal of AF: Interaction Between Hypercoagulability, Electrical Remodelling, and Vascular Destabilization in the Progression of AF study included patients with self-terminating AF who underwent extensive phenotyping at baseline and continuous rhythm monitoring with an implantable loop recorder (ILR). In this subanalysis, ILR data were used to assess the development of AF progression and the diurnal pattern of AF onset: predominant (>80%) nocturnal AF, predominant daytime AF, or mixed AF without a predominant diurnal AF pattern. The median follow-up was 2.2 (1.6-2.8) years. The median age was 66 (59-71) years, and 117 (42%) were women. Predominant nocturnal (n = 40) and daytime (n = 43) AF onset patients had less comorbidities compared to that of mixed (n = 195) AF patients (median 2 vs. 2 vs. 3, respectively, P = 0.012). Diabetes was more common in the mixed group (12% vs. 5% vs. 0%, respectively, P = 0.031), whilst obesity was more frequent in the nocturnal group (38% vs. 12% vs. 27%, respectively, P = 0.028). Progression rates in the nocturnal vs. daytime vs. mixed groups were 5% vs. 5% vs. 24%, respectively (P = 0.013 nocturnal vs. mixed and P = 0.008 daytime vs. mixed group, respectively). Conclusion In self-terminating AF, patients with either predominant nocturnal or daytime onset of AF episodes had less associated comorbidities and less AF progression compared to that of patients with mixed onset of AF

Morcegos cavernícolas da região do Distrito Federal, centro-oeste do Brasil (Mammalia, Chiroptera) Cave bats from the Distrito Federal area in Mid-Western Brazil (Mammalia, Chiroptera)

<abstract language="eng">Between 1989 and 1995, twenty caves in the Distrito Federal area in mid-western Brazil were assessed for bat species richness, frequency, spatial distribution, behavior, reproduction and inter-specific cohabitation. The general state of conservation of the caves was also assessed. Of the 20 caves studied, 12 were less than 100 m long, five between 100 m and 300 m, and three were longerthan 300 m. Twenty-two species of six different families were observed: 16 species belonged to Phyllostomidae, two to Vespertilionidae and Mormoopidae and one to Furipteridae and Emballonuridae. In this study, 17 species were characterized as Distrito Federal cave dwellers. The most prevalent were Desmodus rotundus, Glossophaga soricina and Carollia perspicillata. The least prevalent were Lonchorhina aurita, Pteronotus gymnonotus and Phylloderma stenops. Since some Anoura caudifer, Platyrrhinus lineatus, Myotis nigricans, Micronycteris minuta, and Eptesicus brasiliensis individuals were captured only while going into the caves early in the night, they were not considered cave dwellers. Even though, they probably use the caves as a daytime roosting place. Surprisingly, Lonchophylla dekeyseri, considered to be the only endemic bat species in the Cerrado ecosystem, was observed in three of the surveyed caves. Further biological studies are necessary to determine the biology of L. dekeyseri and the necessity of its conservation. The bat colonies observed were usually of a small size. Few colonies of D. rotundus and Anoura geoffroyi contained more than 300 individuals of both sexes. Only a inale group of L. aurita was observed in the Distrito Federal area. Twelve of the surveyed caves were hard to access and therefore well protected. Four of the caves received some public visitation, two were located near limestone mines, one was located near an urban area. and one had both public visitation and deforestation near its entrance. In this latter cave, no bats were observed after november 1994, probably due to the urbanization process. Special attention should be given to eight of the surveyed caves in any plan made for the conservation of cave bats in the Distrito Federal area. These caves host a high bat diversity (six or more species) and also shelter two rare and one endemic bat species

Clinical utility of the 4S-AF scheme in predicting progression of atrial fibrillation: data from the RACE V study

Aims The recent 4S-AF (scheme proposed by the 2020 ESC AF guidelines to address stroke risk, symptom severity, severity of AF burden and substrate of AF to provide a structured phenotyping of AF patients in clinical practice to guide therapy and assess prognosis) scheme has been proposed as a structured scheme to characterize patients with atrial fibrillation (AF). We aimed to assess whether the 4S-AF scheme predicts AF progression in patients with self-terminating AF. Methods and results We analysed 341 patients with self-terminating AF included in the well-phenotyped Reappraisal of Atrial Fibrillation: Interaction between HyperCoagulability, Electrical remodelling, and Vascular Destabilization in the Progression of AF (RACE V) study. Patients had continuous monitoring with implantable loop recorders or pacemakers. AF progression was defined as progression to persistent or permanent AF or progression of self-terminating AF with >3% burden increase. Progression of AF was observed in 42 patients (12.3%, 5.9% per year). Patients were given a score based on the components of the 4S-AF scheme. Mean age was 65 [interquartile range (IQR) 58-71] years, 149 (44%) were women, 103 (49%) had heart failure, 276 (81%) had hypertension, and 38 (11%) had coronary artery disease. Median CHA(2)DS(2)-VASc (the CHA(2)DS(2)-VASc score assesses thromboembolic risk. C, congestive heart failure/left ventricular dysfunction; H, hypertension; A(2), age >= 75 years; D, diabetes mellitus; S-2, stroke/transient ischaemic attack/systemic embolism; V, vascular disease; A, age 65-74 years; Sc, sex category (female sex)) score was 2 (IQR 2-3), and median follow-up was 2.1 (1.5-2.6) years. The average score of the 4S-AF scheme was 4.6 +/- 1.4. The score points from the 4S-AF scheme did not predict the risk of AF progression [odds ratio (OR) 1.1 95% CI 0.88-1.41, C-statistic 0.53]. However, excluding the symptoms domain, resulting in the 3S-AF (4S-AF scheme without the domain symptom severity, only including stroke risk, severity of AF burden and substrate of AF) scheme, predicted the risk of progression (OR 1.59 95% CI 1.15-2.27, C-statistic 0.62) even after adjusting for sex and age. Conclusions In self-terminating AF patients, the 4S-AF scheme does not predict AF progression. The 3S-AF scheme, excluding the symptom domain, may be a more appropriate score to predict AF progression