Distributed Linear Precoding and User Selection in Coordinated Multicell Systems

In this manuscript we tackle the problem of semidistributed user selection with distributed linear precoding for sum rate maximization in multiuser multicell systems. A set of adjacent base stations (BS) form a cluster in order to perform coordinated transmission to cell-edge users, and coordination is carried out through a central processing unit (CU). However, the message exchange between BSs and the CU is limited to scheduling control signaling and no user data or channel state information (CSI) exchange is allowed. In the considered multicell coordinated approach, each BS has its own set of cell-edge users and transmits only to one intended user while interference to non-intended users at other BSs is suppressed by signal steering (precoding). We use two distributed linear precoding schemes, Distributed Zero Forcing (DZF) and Distributed Virtual Signalto-Interference-plus-Noise Ratio (DVSINR). Considering multiple users per cell and the backhaul limitations, the BSs rely on local CSI to solve the user selection problem. First we investigate how the signal-to-noise-ratio (SNR) regime and the number of antennas at the BSs impact the effective channel gain (the magnitude of the channels after precoding) and its relationship with multiuser diversity. Considering that user selection must be based on the type of implemented precoding, we develop metrics of compatibility (estimations of the effective channel gains) that can be computed from local CSI at each BS and reported to the CU for scheduling decisions. Based on such metrics, we design user selection algorithms that can find a set of users that potentially maximizes the sum rate. Numerical results show the effectiveness of the proposed metrics and algorithms for different configurations of users and antennas at the base stations.

Local Fractional Variational Iteration Method for Local Fractional Poisson Equations in Two Independent Variables

The local fractional Poisson equations in two independent variables that appear in mathematical physics involving the local fractional derivatives are investigated in this paper. The approximate solutions with the nondifferentiable functions are obtained by using the local fractional variational iteration method.

The Prognostic Impact of Renal Failure in Patients with ST-Segment Elevation Acute Myocardial Infarction

INTRODUCTION: Renal insufficiency (RI) is associated with higher morbidity and mortality in patients (P) with coronary artery disease and in P submitted to angioplasty. In ST-segment elevation acute myocardial infarction (STEAMI), this impact has not been well demonstrated. AIM: To evaluate the impact of RI in P with STEAMI. METHODS: We evaluated 160 P admitted with STEAMI, mean age of 62+/-14 years, 76% male. We determined creatinine levels on admission. RI was defined as a level >1.5 mg/dl. Analysis of clinical, electrocardiographic and laboratory variables was performed, in relation to the endpoint defined as the occurrence of death at 30-day follow-up. RESULTS: There were 16 deaths (10%) at 30-day follow-up. P with RI (n=21) were older (68+/-11 vs 61+/-14 years, p<0.001), more often had diabetes (57 vs 24 %, p=0.004) and presented more often with Killip class > or =2 (57 vs 12%, p<0.001). The use of statins (62 vs 83%, p=0.05) and beta-blockers (24 vs 65%, p<0.001) was lower in P with RI. Mortality was higher in RI P (62 vs 2%, p<0.001). The univariate predictors of death were age > or =75 years, diabetes, Killip class > or =2 on admission, RI, non-use of statins and beta-blockers and use of diuretics. In multivariate analysis, independent predictors of death at 30 days were RI (HR 29.6, 95% CI 6.3-139.9, p<0.001) and non-use of beta-blockers (HR 0.13, 95% CI 0.02-1.01, p=0.01). CONCLUSION: In P admitted for STEAMI, the presence of RI was an independent predictor of death at 30 days whereas the usage of beta-blockers was protective.

Analysis of World Economic Variables Using Multidimensional Scaling

Waves of globalization reflect the historical technical progress and modern economic growth. The dynamics of this process are here approached using the multidimensional scaling (MDS) methodology to analyze the evolution of GDP per capita, international trade openness, life expectancy, and education tertiary enrollment in 14 countries. MDS provides the appropriate theoretical concepts and the exact mathematical tools to describe the joint evolution of these indicators of economic growth, globalization, welfare and human development of the world economy from 1977 up to 2012. The polarization dance of countries enlightens the convergence paths, potential warfare and present-day rivalries in the global geopolitical scene.

Impacto da Obesidade nos Resultados após Angioplastia Primária em Doentes com Enfarte Agudo do Miocárdio com Elevação do Segmento ST

INTRODUCTION: Obesity is an important risk factor for the development of diabetes, hypertension, coronary disease, left ventricular dysfunction, stroke and cardiac arrhythmias. Paradoxically, previous studies in patients undergoing elective coronary angioplasty showed a reduction in hospital and long-term mortality in obese patients. The relation with body mass index (BMI) has been less studied in the context of primary angioplasty. OBJECTIVES: To evaluate the impact of obesity on the results of ST-segment elevation acute myocardial infarction treated by primary angioplasty. METHODS: This was a study of 464 consecutive patients with ST-segment elevation acute myocardial infarction undergoing primary angioplasty, 78% male, mean age 61 +/- 13 years. We assessed in-hospital, 30-day and one-year mortality according to BMI. Patients were divided into three groups according to BMI: normal--18-24.9 kg/m2 (n = 171); overweight--25-29.9 kg/m2 (n = 204); and obese-- > 30 kg/m2 (n = 89). RESULTS: Obese patients were younger (ANOVA, p < 0.001) and more frequently male (p = 0.014), with more hypertension (p = 0.001) and dyslipidemia (p = 0.006). There were no differences in the prevalence of diabetes, previous cardiac history, heart failure on admission, anterior location, multivessel disease, peak total CK or medication prescribed, except that obese patients received more beta-blockers (p = 0.049). In-hospital mortality was 9.9% for patients with normal BMI, 3.4% for overweight patients and 6.7% for obese patients (p = 0.038). Mortality at 30 days was 11 4.4% and 7.8% (p = 0.032) and at one year 12.9%, 4.9% and 9% (p = 0.023), respectively. On univariate analysis, overweight was the only BMI category with a protective effect; however, after multivariate logistic regression analysis, adjusted for confounding variables, none of the BMI categories could independently predict outcome. CONCLUSIONS: Overweight patients had a better prognosis after primary angioplasty for ST-segment elevation acute myocardial infarction compared with other BMI categories, but this was dependent on other potentially confounding variables.

Variáveis Ecocardiográficas Predizentes de Terapêuticas Apropriadas de Taquidisritmias Ventriculares em Doentes Submetidos a Terapêutica de Ressincronização Cardíaca Combinada

INTRODUCTION: The significant risk of sudden arrhythmic death in patients with congestive heart failure and electromechanical ventricular dyssynchrony has led to increased use of combined cardiac resynchronization therapy defibrillator (CRT-D) devices. OBJECTIVES: To evaluate the echocardiographic variables in patients undergoing CRT-D that predict the occurrence of appropriate therapies (AT) for ventricular tachyarrhythmia. METHODS: We analyzed 38 consecutive patients (mean age 60 +/- 12 years, 63% male) with echocardiographic evaluation before and 6 months after CRT-D implantation. Patients with AT were identified in a mean follow-up of 471 +/- 323 days. A standard echocardiographic study was performed including tissue Doppler imaging (TDI). Responders were defined as patients with improvement in NYHA class of < or = 1 in the first six months, and reverse remodeling as a decrease in left ventricular end-systolic volume of < or = 15% and/or an increase in left ventricular ejection fraction of > 25%. RESULTS: The responder rate was 74%, and the reverse remodeling rate was 55%. AT occurred in 21% of patients, who presented with greater left ventricular end-diastolic internal diameter (LVEDD) before implantation (86 +/- 8 vs. 76 +/- 11 mm, p = 0.03) and at 6 months (81 +/- 8 vs. 72 +/- 14 mm, p = 0.08), and increased left ventricular end-systolic internal diameter (66 +/- 14 vs. 56 +/- 14 mm, p = 0.03) and lower ejection fraction (24 +/- 6 vs. 34 +/- 14%, p = 0.08) at 6 months. In the group with AT, the responder rate was lower (38 vs. 83%, p = 0.03), without significant differences in reverse remodeling (38% for the AT group vs. 60%, p = 0.426) or in the other variables. By univariate analysis, predictors of AT were LVEDD before implantation and E' after implantation. Age, gender, ischemic etiology, use of antiarrhythmic drugs, reverse remodeling and the other echocardiographic parameters did not predict AT. In multivariate logistic regression analysis, both LVEDD before implantation (OR 1.24, 95% CI 1.04-1.48, p = 0.019) and postimplantation E' (OR 0.27, 95% CI 0.09-0.76, p = 0.014) remained as independent predictors of AT. CONCLUSIONS: In patients undergoing CRT-D, episodes of ventricular tachyarrhythmia occur with high incidence, independently of echocardiographic response, with LVEDD before implantation and E' after implantation as the only independent predictors of AT in the medium-term. These results highlight the importance of combined devices with defibrillation capability.

Resultados da Angioplastia Primária num Centro de Referência. Evolução Intra-Hospitalar

INTRODUCTION: Primary angioplasty is accepted as the preferred treatment for acute myocardial infarction in the first 12 hours. However, outcomes depend to a large extent on the volume of activity and experience of the center. Continuous monitoring of methods and results obtained is therefore crucial to quality control. OBJECTIVE: To describe the demographic, clinical and angiographic characteristics as well as in-hospital outcomes of patients undergoing primary PCI in a high-volume Portuguese center. We also aimed to identify variables associated with in-hospital mortality in this population. METHODS: This was a retrospective registry of consecutive primary PCIs performed at Santa Marta Hospital between January 2001 and August 2007. Demographic, clinical, and angiographic characteristics and in-hospital outcomes were analyzed. Independent predictors of in-hospital mortality were identified by multivariate logistic regression analysis. RESULTS: A total of 1157 patients were identified, mean age 61+/-12 years, 76% male. Mean pain-to-balloon time was 7.6 hours and primary angiographic success was 88%. Overall in-hospital mortality was 6.9%, or 5.5% if patients presenting in cardiogenic shock were excluded from the analysis. Previous history of heart failure, cardiogenic shock on admission, invasive ventilatory support, major hemorrhage, and age over 75 years were found to be associated with increased risk of in-hospital death. Conclusions: In this center primary PCI is effective and safe. Angiographic success rates and in-hospital mortality and morbidity are similar to other international registries. Patients at increased risk for adverse outcome can be identified by simple clinical characteristics such as advanced age, cardiogenic shock on admission, mechanical ventilation and major hemorrhage during hospitalization.

Thermographic and visible spectrum camera calibration for marine robotic target detection

Oceans - San Diego, 2013

Calibration Method for Underwater Visual Ground-Truth System

This work presents an automatic calibration method for a vision based external underwater ground-truth positioning system. These systems are a relevant tool in benchmarking and assessing the quality of research in underwater robotics applications. A stereo vision system can in suitable environments such as test tanks or in clear water conditions provide accurate position with low cost and flexible operation. In this work we present a two step extrinsic camera parameter calibration procedure in order to reduce the setup time and provide accurate results. The proposed method uses a planar homography decomposition in order to determine the relative camera poses and the determination of vanishing points of detected lines in the image to obtain the global pose of the stereo rig in the reference frame. This method was applied to our external vision based ground-truth at the INESC TEC/Robotics test tank. Results are presented in comparison with an precise calibration performed using points obtained from an accurate 3D LIDAR modelling of the environment.

Structured Light System Calibration for Perception in Underwater Tanks

The process of visually exploring underwater environments is still a complex problem. Underwater vision systems require complementary means of sensor information to help overcome water disturbances. This work proposes the development of calibration methods for a structured light based system consisting on a camera and a laser with a line beam. Two different calibration procedures that require only two images from different viewpoints were developed and tested in dry and underwater environments. Results obtained show, an accurate calibration for the camera/projector pair with errors close to 1 mm even in the presence of a small stereos baseline.

Seroepidemiology and occupational and environmental variables for leptospirosis, brucellosis and toxoplasmosis in slaughterhouse workers in the Paraná State, Brazil

Leptospirosis, brucellosis and toxoplasmosis are widely-distributed zoonosis, being the man an accidental participant of their epidemiological chains. The aim of this paper was to make a seroepidemiological report and identify occupational and environmental variables related to these illnesses in 150 workers in a slaughterhouse in the Northern region of Paraná. For the diagnosis of leptospirosis a microscopical seroagglutination test was applied; for brucellosis, the tamponated acidified antigen test and the 2-mercaptoetanol tests were used, and for toxoplasmosis the indirect immunofluorescence reaction test. For each employee an epidemiological survey was filled, which investigated occupational and environmental variables which could be associated with these infections. Positive results for leptospirosis were found in 4.00% of the samples, for brucellosis in 0.66% of samples and toxoplasmosis in 70.00%. From the three diseases researched, only the results for leptospirosis suggest occupational infection.

Controlo inteligente de um Sistema de Levitação Magnética

A levitação magnética tem sido um tema bastante investigado sobretudo devido à sua utilização em sistemas ferroviários de transportes. É o método ideal quando existe a necessidade em aplicações de restringir do contacto físico, ou a conveniência, em termos energéticos, de eliminar o atrito. O princípio de funcionamento é simples, um eletroíman cria uma força sobre um objeto ferromagnético que contraria a gravidade. Contudo um sistema de levitação por atração é instável e não linear, o que significa a necessidade de implementar um controlador para satisfazer as características de estabilidade desejadas. Ao longo deste projeto serão descritos os procedimentos teóricos e práticos que foram tomados na criação de um sistema de levitação eletromagnética. Desde a conceção física do sistema, como escolha do sensor, condicionamento de sinal ou construção do eletroíman, até aos procedimentos matemáticos que permitiram a modelação do sistema e criação de controladores. Os controladores clássicos, como o PID ou em avanço de fase, foram projetados através da técnica do Lugar Geométrico de Raízes. No projeto do controlador difuso, pelo contrário não se fez uso da modelação do sistema ou de qualquer relação matemática entre as variáveis. A utilização desta técnica de controlo destacou-se pela usa simplicidade e rapidez de implementação, fornecendo um bom desempenho ao sistema. Na parte final do relatório os resultados obtidos pelos diferentes métodos de controlo são analisados e apresentadas as respetivas conclusões. Estes resultados revelam que para este sistema, relativamente aos outros métodos, o controlador difuso apresenta o melhor desempenho tanto ao nível da resposta transitória, como em regime permanente.

Predictive factors of mortality in burn patients

Burn mortality statistics may be misleading unless they account properly for the many factors that can influence outcome. Such estimates are useful for patients and others making medical and financial decisions concerning their care. This study aimed to define the clinical, microbiological and laboratorial predictors of mortality with a view to focus on better burn care. Data were collected using independent variables, which were analyzed sequentially and cumulatively, employing univariate statistics and a pooled, cross-sectional, multivariate logistic regression to establish which variables better predict the probability of mortality. Survivors and non-survivors among burn patients were compared to define the predictive factors of mortality. Mortality rate was 5.0%. Higher age, larger burn area, presence of fungi in the wound, shorter length of stay and the presence of multi-resistant bacteria in the wound significantly predicted increased mortality. The authors conclude that those patients who are most apt to die are those with age > 50 years, with limited skin donor sites and those with multi-resistant bacteria and fungi in the wound.

Adhesive selection for single lap bonded joints: Experimentation and advanced techniques for strength prediction

The integrity of multi-component structures is usually determined by their unions. Adhesive-bonding is often used over traditional methods because of the reduction of stress concentrations, reduced weight penalty, and easy manufacturing. Commercial adhesives range from strong and brittle (e.g., Araldite® AV138) to less strong and ductile (e.g., Araldite® 2015). A new family of polyurethane adhesives combines high strength and ductility (e.g., Sikaforce® 7888). In this work, the performance of the three above-mentioned adhesives was tested in single lap joints with varying values of overlap length (LO). The experimental work carried out is accompanied by a detailed numerical analysis by finite elements, either based on cohesive zone models (CZM) or the extended finite element method (XFEM). This procedure enabled detailing the performance of these predictive techniques applied to bonded joints. Moreover, it was possible to evaluate which family of adhesives is more suited for each joint geometry. CZM revealed to be highly accurate, except for largely ductile adhesives, although this could be circumvented with a different cohesive law. XFEM is not the most suited technique for mixed-mode damage growth, but a rough prediction was achieved.