Fermions from photons: Bosonization of QED in 2+1 dimensions

We perform the complete bosonization of 2+1 dimensional QED with one fermionic flavor in the Hamiltonian formalism. The Fermi operators are explicitly constructed in terms of the vector potential and the electric field. We carefully specify the regularization procedure involved in the definition of these operators, and calculate the fermionic bilinears and the energy - momentum tensor. The algebra of bilinears exhibits the Schwinger terms which also appear in perturbation theory. The bosonic Hamiltonian is a local, polynomial functional of $A_i$ and $E_i$, and we check explicitly the Lorentz invariance of the resulting bosonic theory. Our construction is conceptually very similar to Mandelstam's construction in 1+1 dimensions, and is dissimilar from the recent bosonization attempts in 2+1 dimensions, which hinge crucially on the presence of a Chern - Simons term.Comment: 30 pages, LA - UR - 93 - 200

A Candidate for Exact Continuum Dual Theory for Scalar QED3_3

We discuss a possible exact equivalence of the Abelian Higgs model and a scalar theory of a magnetic vortex field in 2+1 dimensions. The vortex model has a current - current interaction and can be viewed as a strong coupling limit of a massive vector theory. The fixed point structure of the theory is discussed and mapped into fixed points of the Higgs model.Comment: 17 pages, 1 figure available on request, LA-UR-93-83

Vortex condensation in a model of random ϕ4\phi^{4}-graphs

We consider a soluble model of large $\phi^{4}$-graphs randomly embedded in one compactified dimension; namely the large-order behaviour of finite-temperature perturbation theory for the partition function of the anharmonic oscillator. We solve the model using semi-classical methods and demonstrate the existence of a critical temperature at which the system undergoes a second-order phase transition from $D=1$ to $D=0$ behaviour. Non-trivial windings of the closed loops in a graph around the compactified time direction are interpreted as vortices. The critical point has a natural interpretation as the temperature at which these vortices condense and disorder the system. We show that the vortex density increases rapidly in the critical region indicating the breakdown of the dilute vortex gas approximation at this point. We discuss the relation of this phenomenon to the Berezinskii-Kosterlitz-Thouless transition in the $D=1$ matrix model formulated on a circle.Comment: 12 pages, LaTeX, (5 figures not included

Coronary artery fistulas morphology in coronary computed tomography angiography

Background: The aim of the study was to evaluate coronary artery fistulas (CAFs) in coronary computed tomography angiography (coronary CTA) and verify whether there is correlation between the fistula’s morphology and other cardiac functional findings and clinical data.Materials and methods: A group of 14,308 patients who were diagnosed in coronary CTA was retrospectively analysed. Achieved data were related to referrals.Results: Coronary artery fistula frequency was 0.43% in the examined population. The assessment of coronary artery disease was the most frequent indication for the examination. In 2 out of 3 cases the diagnosis of CAFs was incidental. Fistulas to cardiac chambers were significantly shorter than those to other vascular structures (19.9 vs. 61.8 mm, respectively, p = 0.001). Pulmonary trunk was most often the drainage site. Fistulas with singular supply and drainage constituted the majority. The new morphologic classification of CAFs was introduced with linear, spiral, aneurysmal, grid-like and mixed types. Most numerous was the spiral type group. Patients with aneurysmal fistulas had a tendency for wider diameter of aorta and pulmonary trunk. Smallest left ventricle fraction was observed in gridlike fistulas (48.0%, comparing to 59.2% for all patients with fistulas, p = 0.001). Concomitant abnormalities were found in 13.1% of CAFs patients.Conclusions: Computed tomography angiography has proven to be a useful tool in CAFs detection and morphological assessment. Proposed classification may simplify the predictions whether fistula has a significant influence on cardiac function; however, further studies are needed

Neurovascular unit dysfunction with blood-brain barrier hyperpermeability contributes to major depressive disorder: a review of clinical and experimental evidence

About one-third of people with major depressive disorder (MDD) fail at least two antidepressant drug trials at 1 year. Together with clinical and experimental evidence indicating that the pathophysiology of MDD is multifactorial, this observation underscores the importance of elucidating mechanisms beyond monoaminergic dysregulation that can contribute to the genesis and persistence of MDD. Oxidative stress and neuroinflammation are mechanistically linked to the presence of neurovascular dysfunction with blood-brain barrier (BBB) hyperpermeability in selected neurological disorders, such as stroke, epilepsy, multiple sclerosis, traumatic brain injury, and Alzheimer’s disease. In contrast to other major psychiatric disorders, MDD is frequently comorbid with such neurological disorders and constitutes an independent risk factor for morbidity and mortality in disorders characterized by vascular endothelial dysfunction (cardiovascular disease and diabetes mellitus). Oxidative stress and neuroinflammation are implicated in the neurobiology of MDD. More recent evidence links neurovascular dysfunction with BBB hyperpermeability to MDD without neurological comorbidity. We review this emerging literature and present a theoretical integration between these abnormalities to those involving oxidative stress and neuroinflammation in MDD. We discuss our hypothesis that alterations in endothelial nitric oxide levels and endothelial nitric oxide synthase uncoupling are central mechanistic links in this regard. Understanding the contribution of neurovascular dysfunction with BBB hyperpermeability to the pathophysiology of MDD may help to identify novel therapeutic and preventative approaches