Spontaneous formation of domain wall lattices in two spatial dimensions

We show that the process of spontaneous symmetry breaking can trap a field theoretic system in a highly non-trivial state containing a lattice of domain walls. In one large compact space dimension, a lattice is inevitably formed. In two dimensions, the probability of lattice formation depends on the ratio of sizes L_x, L_y of the spatial dimensions. We find that a lattice can form even if R=L_y/L_x is of order unity. We numerically determine the number of walls in the lattice as a function of L_x and L_y.Comment: 6 pages, 6 figures. Background material added and minor corrections included. Final version to be published in Phys. Rev.

Predicting the critical density of topological defects in O(N) scalar field theories

O(N) symmetric $\lambda \phi^4$ field theories describe many critical phenomena in the laboratory and in the early Universe. Given N and $D\leq 3$, the dimension of space, these models exhibit topological defect classical solutions that in some cases fully determine their critical behavior. For N=2, D=3 it has been observed that the defect density is seemingly a universal quantity at T_c. We prove this conjecture and show how to predict its value based on the universal critical exponents of the field theory. Analogously, for general N and D we predict the universal critical densities of domain walls and monopoles, for which no detailed thermodynamic study exists. This procedure can also be inverted, producing an algorithm for generating typical defect networks at criticality, in contrast to the canonical procedure, which applies only in the unphysical limit of infinite temperature.Comment: 4 pages, 3 figures, uses RevTex, typos in Eq.(11) and (14) correcte

Ulcerative colitis: let's talk about extent

Ulcerative colitis (UC) is a chronic inflammatory disease in which clinical course varies substantially between patients. The extent of the disease is usually pointed out as one of the factors responsible for this variation. With this study, we pretended to evaluate the differences in natural history and pharmacological therapy prescription between left-sided and extended UC

Tromboendarterectomia Pulmonar em Portugal: Experiência Inicial

Introduction: Surgical treatment for chronic thromboembolic pulmonary hypertension (CTEPH) is challenging. Most Portuguese patients with CTEPH have been referred to foreign institutions for treatment, with significant social and economic costs. To meet this emerging need, the cardiothoracic surgery department of Hospital de Santa Marta, Lisbon, has developed a dedicated program for pulmonary thromboendarterectomy (PTE). We hereby present the results for the first 19 patients treated. Methods: We conducted a retrospective analysis of all 19 patients who underwent PTE at Hospital de Santa Marta between 2008 and April 2019. Results: Since 2008, a total of 19 patients have undergone PTE in our department. The procedure was performed with good outcomes in both survival and functional recovery. At the very beginning of the series two patients died perioperatively, before all the team underwent formal training at the Royal Papworth Hospital, UK, with no early deaths since. Postoperative complications were similar to other published series. During 11 years of follow-up, there were three late deaths, all in patients with residual pulmonary arterial hypertension. At the latest follow-up (October 2019), all surviving patients showed significant functional recovery, all in NYHA class I or II, with only one patient on vasodilator therapy with sildenafil (the first in the series, operated in 2008). Conclusions: PTE is a demanding procedure, in which outcomes are related to volume and accumulated experience, however it can be performed safely and with reproducible results by a properly prepared dedicated team with a well-controlled learning curve. More patients and multidisciplinary experience will be needed to further improve and streamline results.info:eu-repo/semantics/publishedVersio

Methods of isolation and identification of pathogenic and potential pathogenic bacteria from skins and tannery effluents

Currently there is no standard protocol available within the leather industry to isolate and identify pathogenic bacteria from hides, skins or tannery effluent. This study was therefore carried out to identify simple but effective methods for isolation and identification of bacterial pathogens from the effluent and skins during leather processing. Identification methods based on both phenotypic and genotypic characteristics were investigated. Bacillus cereus and Pseudomonas aeruginosa were used as indicator bacteria to evaluate the isolation and identification methods. Decontaminated calfskins were inoculated with a pure culture of the above mentioned bacterial species followed by a pre-tanning and chromium tanning processes. Effluent samples were collected and skins were swabbed at the end of each processing stage. Bacterial identification was carried out based on the phenotypic characteristics; such as colony appearance on selective solid media, cell morphology following a standard Gram-staining and spore staining techniques, and biochemical reactions, e.g., the ability of a bacterial species to ferment particular sugars and ability to produce certain enzymes. Additionally, an identification system based on bacterial phenotypic characteristics, known as Biolog® system was applied. A pulsed-filed gel electrophoresis (PFGE) method for bacterial DNA fingerprinting was also evaluated and used for the identification of the inoculated bacteria. The methods described in the study were found to be effective for the identification of pathogenic bacteria from skins and effluent

Health monitoring of civil engineering infrastructures with optical fiber sensors

Structural health monitoring is a fundamental tool to guaranty the civil infrastructure lifetime. In this paper, the monitoring of an adobe structure with optical fiber sensors is reported. Static and dynamic measurements were made during a destructive test on a full-scale wall, with an optical fiber accelerometer and a network of thirteen multiplexed displacement sensors. The measured values shown a decrease of 47.8 % in the first natural frequency value, between the initial situation (structure undamaged) and after the cyclic test (structure damaged). The results show very good agreement (maximum relative error in terms of structural frequency of 2.08 %) between the results obtained using electronic sensing technology and the optical sensing technology

Brucella endocarditis of the aortic valve

Brucella endocarditis was diagnosed in two patients with acute renal failure. Both patients had major aortic insufficiency, congestive cardiac failure and clinical and laboratory signs of an active infection, although adequate antibacterial therapy had already been introduced. Replacement of the aortic valve, together with the aortic root in one of the cases, were carried out as emergency procedures, followed by antibacterial treatment with rifampicin, doxycycline and co-trimoxazole. Both patients left the hospital cured and are well 2.5 and 2 years after the surgery, respectively

Uma Aplicação do Teorema dos Resíduos

O movimento rotativo de um rotor numa região confinada determina o escoamento do fluído envolvente e o desenvolvimento de forças de interacção fluído-estrutura, cujo conhecimento é essencial na previsão do comportamento dinâmico deste sistema. A determinação explícita das forças referidas a partir das equações de Navier-Stokes conduz à necessidade de resolução de integrais definidos do tipo [equação]. A aplicação de uma forma particular do teorema dos resíduos da análise complexa constitui a solução natural do problema anterior, concretizada recorrendo ao auxílio de um manipulador simbólico para fazer face à extensão das manipulações algébricas necessárias