2,571 research outputs found
Field theory of scaling lattice models. The Potts antiferromagnet
In contrast to what happens for ferromagnets, the lattice structure
participates in a crucial way to determine existence and type of critical
behaviour in antiferromagnetic systems. It is an interesting question to
investigate how the memory of the lattice survives in the field theory
describing a scaling antiferromagnet. We discuss this issue for the square
lattice three-state Potts model, whose scaling limit as T->0 is argued to be
described exactly by the sine-Gordon field theory at a specific value of the
coupling. The solution of the scaling ferromagnetic case is recalled for
comparison. The field theory describing the crossover from antiferromagnetic to
ferromagnetic behaviour is also introduced.Comment: 11 pages, to appear in the proceedings of the NATO Advanced Research
Workshop on Statistical Field Theories, Como 18-23 June 200
Direct and Inverse Variational Problems on Time Scales: A Survey
We deal with direct and inverse problems of the calculus of variations on
arbitrary time scales. Firstly, using the Euler-Lagrange equation and the
strengthened Legendre condition, we give a general form for a variational
functional to attain a local minimum at a given point of the vector space.
Furthermore, we provide a necessary condition for a dynamic
integro-differential equation to be an Euler-Lagrange equation (Helmholtz's
problem of the calculus of variations on time scales). New and interesting
results for the discrete and quantum settings are obtained as particular cases.
Finally, we consider very general problems of the calculus of variations given
by the composition of a certain scalar function with delta and nabla integrals
of a vector valued field.Comment: This is a preprint of a paper whose final and definite form will be
published in the Springer Volume 'Modeling, Dynamics, Optimization and
Bioeconomics II', Edited by A. A. Pinto and D. Zilberman (Eds.), Springer
Proceedings in Mathematics & Statistics. Submitted 03/Sept/2014; Accepted,
after a revision, 19/Jan/201
Lúpus Erythematosus
O Lúpus Eritematoso Sistémico (LES) é uma doença multissistémica, auto-imune, caracterizada por inflamação vascular e do tecido conjuntivo, com anticorpos antinucleares. As manifestações clÃnicas são variáveis, com uma história natural progressiva e imprevisÃvel.
Apresentamos o caso de uma adolescente, com antecedentes de artrite dos joelhos, febre
e astenia de etiologia não esclarecida, com um ano de evolução. Internada na Unidade de
Cuidados Intensivos Pediátricos por pneumonia bilateral a Streptococcus pneumoniae complicada com derrame pleural, anasarca e hematúria macroscópica. Iniciou
antibioticoterapia, com evolução favorável, após o que se verifica agravamento clÃnico,
com reaparecimento do derrame pleural, lesões vesiculares disseminadas sugestivas de
etiologia herpética, hipertensão arterial sintomática e convulsão tónico-clónica generalizada.
Da investigação, destaca-se estudo imunológico compatÃvel com LES em actividade,
poliserosite, proteinúria nefrótica, nefrite lúpica classe IV e anemia grave
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Arrendamento privado em Portugal: uma leitura a partir da regulação das rendas
Este artigo contribui para o debate do papel do Estado na regulação do sector de arrendamento privado em Portugal num momento em que é implementado um Novo Regime de Arrendamento Urbano. A informação estatÃstica disponÃvel, nomeadamente sobre a duração dos contratos e os valores das rendas, alerta para uma tendência de precarização dos contratos de arrendamento entre 2001 e 2011 e para o declÃnio da oferta de arrendamento a preços acessÃveis. Este artigo enfatiza a importância de medidas de apoio ao mercado de arrendamento privado, focadas simultaneamente no lado da oferta e da procura, que estimulem a oferta de habitação a preços acessÃveis
Coexisting primary Sjögren’s syndrome and sarcoidosis: coincidence, mutually exclusive conditions or syndrome?
Herein, we describe a 44-year-old female diagnosed with histologically proven coexistence of primary Sjögren's syndrome and sarcoidosis with pulmonary and muscular involvement. The differential diagnosis may be difficult, but this is not an exceptional case, which highlights the need to critically revise the consideration of sarcoidosis as an exclusion for primary Sjögren's syndrome, as established in current classification criteria
Polypharmacy, potentially serious clinically relevant drug-drug interactions, and inappropriate medicines in elderly people with type 2 diabetes and their impact on quality of life
The aim of the study is to investigate the patterns of polypharmacy, clinical-relevant drug-drug interactions (DDIs), and potentially inappropriate medicines (PIMs), and whether polypharmacy, potential serious clinically-relevant DDIs, or PIMs can be associated with low quality of life (QoL) index scores of older adults with type 2 diabetes (T2D). A cross-sectional study was conducted using data of 670 elderly T2D sub-cohort from a nationwide pharmacy-based intensive monitoring study of inception cohort of T2D in Portugal. 72.09% were found on polypharmacy (≥5 medicines). Participants on polypharmacy were mostly females (P = .0115); more obese (P = .0131); have more comorbid conditions (P < .0001); more diabetes complications (P < .0001); and use more of glucose lowering drugs (P = .0326); insulin (P < .0001); chronic medicines (P < .0001); and have higher diabetes duration (P = .0088) than those without polypharmacy. 10.59% of the participants were found to have potential serious clinically relevant DDIs. The most frequent drug-combinations were angiotensin-converting enzyme (ACE) inhibitors with angiotensin-receptor blockers (ARBs), aspirin with Selective serotonin reuptake inhibitors (SSRIs), and clopidogrel with calcium channel blockers. PIMs are found in 36.11% of the participants. The most common PIMs were benzodiazepines, long-acting sulfonylureas, and iron overdose. The adjusted multivariate models show that Polypharmacy, PIMs, and potential serious clinically relevant DDIs were associated with lower QoL index scores (OR 1.80 95% CI 1.15-2.82), (OR 1.57 95% CI 1.07-2.28), and (OR 1.34 95% CI 0.73-2.48) respectively. The study shows that polypharmacy, potential serious clinical-relevant DDIs, and PIMs may correlate with risk of reduced health related QoL outcome of older adults with T2D.publishersversionpublishe
Towards general cooperative game playing
Attempts to develop generic approaches to game playing have been around for several years in the field of Artificial Intelligence. However, games that involve explicit cooperation among otherwise competitive players cooperative negotiation games have not been addressed by current approaches. Yet, such games provide a much richer set of features, related with social aspects of interactions, which make them appealing for envisioning real-world applications. This work proposes a generic agent architecture Alpha to tackle cooperative negotiation games, combining elements such as search strategies, negotiation, opponent modeling and trust management. The architecture is then validated in the context of two different games that fall in this category Diplomacy and Werewolves. Alpha agents are tested in several scenarios, against other state-of-the-art agents. Besides highlighting the promising performance of the agents, the role of each architectural component in each game is assessed. (c) Springer International Publishing AG, part of Springer Nature 2018
Diagnostic Accuracy of Bone Turnover Markers and Bone Histology in Patients With CKD Treated by Dialysis
BACKGROUND:
The management of chronic kidney disease-mineral and bone disorder requires the assessment of bone turnover, which most often is based on parathyroid hormone (PTH) concentration, the utility of which remains controversial.
STUDY DESIGN:
Cross-sectional retrospective diagnostic test study.
SETTING & PARTICIPANTS:
492 dialysis patients from Brazil, Portugal, Turkey, and Venezuela with prior bone biopsy and stored (-20 °C) serum.
INDEX TESTS:
Samples were analyzed for PTH (intact [iPTH] and whole PTH), bone-specific alkaline phosphatase (bALP), and amino-terminal propeptide of type 1 procollagen (P1NP).
REFERENCE TEST:
Bone histomorphometric assessment of turnover (bone formation rate/bone surface [BFR/BS]) and receiver operating characteristic curves for discriminating diagnostic ability.
RESULTS:
The biomarkers iPTH and bALP or combinations thereof allowed discrimination of low from nonlow and high from nonhigh BFR/BS, with an area under the receiver operating characteristic curve > 0.70 but 323.0 pg/mL. The best cutoff for bALP to discriminate low from nonlow BFR/BS was <33.1 U/L, and for high from nonhigh BFR/BS, 42.1U/L. Using the KDIGO practice guideline PTH values of greater than 2 but less than 9 times the upper limit of normal, sensitivity and specificity of iPTH level to discriminate low from nonlow turnover bone disease were 65.7% and 65.3%, and to discriminate high from nonhigh were 37.0% and 85.8%, respectively.
LIMITATIONS:
Cross-sectional design without consideration of therapy. Potential limited generalizability with samples from 4 countries.
CONCLUSIONS:
The serum biomarkers iPTH, whole PTH, and bALP were able to discriminate low from nonlow BFR/BS, whereas iPTH and bALP were able to discriminate high from nonhigh BFR/BS. Prospective studies are required to determine whether evaluating trends in biomarker concentrations could guide therapeutic decisions.info:eu-repo/semantics/publishedVersio
Non drowsy obstructive sleep apnea as a potential cause of resistant hypertension: a case report
<p>Abstract</p> <p>Background</p> <p>Obstructive sleep apnea (OSA) and arterial hypertension (AH) are common and underrecognized medical disorders. OSA is a potential risk factor for the development of AH and/or may act as a factor complicating AH management. The symptoms of excessive daytime sleepiness (EDS) are considered essential for the initiation of continuous positive airway pressure (CPAP) therapy, which is a first line treatment of OSA. The medical literature and practice is controversial about the treatment of people with asymptomatic OSA. Thus, OSA patients without EDS may be left at increased cardiovascular risk.</p> <p>Case presentation</p> <p>The report presents a case of 42year old Asian woman with symptoms of heart failure and angina like chest pain upon admission. She didnt experience symptoms of EDS, and the Epworth Sleepiness Scale was seven points. Snoring was reported on direct questioning. The patient had prior medical history of three unsuccessful pregnancies complicated by gestational AH and preeclampsia with C-section during the last pregnancy. The admission blood pressure (BP) was 200/120mm Hg. The patients treatment regimen consisted of five hypotensive medications including diuretic. However, a target BP wasnt achieved in about one and half month. The patient was offered to undergo a polysomnography (PSG) study, which she rejected. One month after discharge the PSG study was done, and this showed an apnea-hypopnea index (AHI) of 46 events per hour. CPAP therapy was initiated with a pressure of 11H<sub>2</sub>0cm. After 2months of compliant CPAP use, adherence to pharmacologic regimen and lifestyle modifications the patients BP decreased to 134/82mm Hg.</p> <p>Conclusions</p> <p>OSA and AH are common and often underdiagnosed medical disorders independently imposing excessive cardiovascular risk on a diseased subject. When two conditions coexist the cardiovascular risk is likely much greater. This case highlights a possible clinical phenotype of OSA without EDS and its association with resistant AH. Most importantly a good hypotensive response to medical treatment in tandem with CPAP therapy was achieved in this patient. Thus, it is reasonable to include OSA in the differential list of resistant AH, even if EDS is not clinically obvious.</p
Joint use of data and modeling in coastal wave transformation
In the framework of a research project entitled "BRISA-BReaking waves and Induced SAnd transport", a methodology was devised to characterize the waves joining together in-situ measurements and numerical wave propagation models. With this goal in mind, a number of in-situ measurements were made, for selected positions in front of Praia de Faro (South Portugal), during four days (25th to 28th March, 2009) by using different types of equipments (e.g., resistive wave gauges, pressure sensors, currentmeters and a new prototype pore pressure sensor using optical fibre). Wave records were obtained simultaneously offshore (at a water depth of 11.7 m below mean sea level, MSL) and at the surf and swash zones. The data processing and analysis were made by applying classical time domain techniques. Numerical simulations of the wave propagation between offshore and inshore for the measurement period were performed with two numerical models, a 1D model based on linear theory and a nonlinear Boussinesq-type model, COULWAVE, both forced by the measured offshore wave conditions of 27th March 2009. Comparisons between numerical results and field data for the pressure sensors placed in the surf and swash zones were made and discussed. This approach enables to evaluate the performance of those models to simulate those specific conditions, but also to validate the models by gaining confidence on their use in other conditions.Science and Technology Foundation of the Ministry of Science, Technology and Higher Education, Portugal [SFRH/BPD/20508/2004]info:eu-repo/semantics/publishedVersio
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